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Meshcheryakov, Yuri, Alexandre Divakov, Natali Zhigacheva, and Boris Barakhtin. "Multiscale Deformation and Dynamic Recrystallization in Shock Deformed Aluminum Alloy." Materials Science Forum 794-796 (June 2014): 815–20. http://dx.doi.org/10.4028/www.scientific.net/msf.794-796.815.
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Two regimes, equilibrium and non-equilibrium interaction of shock wave and inner structure of solid are studied. The theoretical analysis of the regimes is carried out by using the concept of the meso-macro momentum exchange. As a test material for the experiments, D16 Al alloy is taken, firstly because of its initial heterogeneity in equilibrium regime of dynamic straining and, secondly, due to increasing heterogeneity in non-equilibrium regime. Shock tests of D16 Al alloy within impact velocity range of 85÷450m/sevidence that maximum dynamic strength is realized under conditions: (i) equilibrium regime of meso-macro momentum exchange, (ii) velocity defect equals to mean velocity variation. In non-equilibrium regime, the shock-induced dynamic recrystallization occurs, which is investigated with the metallography and X-ray analysis.
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Konovalov, Pavel, Daria Mangileva, Arsenii Dokuchaev, Olga Solovyova, and Alexander V. Panfilov. "Rotational Activity around an Obstacle in 2D Cardiac Tissue in Presence of Cellular Heterogeneity." Mathematics 9, no. 23 (November 30, 2021): 3090. http://dx.doi.org/10.3390/math9233090.
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Waves of electrical excitation rotating around an obstacle is one of the important mechanisms of dangerous cardiac arrhythmias occurring in the heart damaged by a post-infarction scar. Such a scar is also surrounded by the region of heterogeneity called a gray zone. In this paper, we perform the first comprehensive numerical study of various regimes of wave rotation around an obstacle surrounded by a gray zone. We use the TP06 cellular ionic model for human cardiomyocytes and study how the period and the pattern of wave rotation depend on the radius of a circular obstacle and the width of a circular gray zone. Our main conclusions are the following. The wave rotation regimes can be subdivided into three main classes: (1) functional rotation, (2) scar rotation and the newly found (3) gray zone rotation regimes. In the scar rotation regime, the wave rotates around the obstacle, while in the gray zone regime, the wave rotates around the gray zone. As a result, the period of rotation is determined by the perimeter of the scar, or gray zone perimeter correspondingly. The transition from the scar to the gray rotation regimes can be determined from the minimal period principle, formulated in this paper. We have also observed additional regimes associated with two types of dynamical instabilities which may affect or not affect the period of rotation. The results of this study can help to identify the factors determining the period of arrhythmias in post-infarction patients.
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Duflot, R., K. Eyvindson, and M. Mönkkönen. "Management diversification increases habitat availability for multiple biodiversity indicator species in production forests." Landscape Ecology 37, no. 2 (November 29, 2021): 443–59. http://dx.doi.org/10.1007/s10980-021-01375-8.
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Abstract Context Forest biodiversity is closely linked to habitat heterogeneity, while forestry actions often cause habitat homogenization. Alternative approaches to even-aged management were developed to restore habitat heterogeneity at the stand level, but how their application could promote habitat diversity at landscape scale remains uncertain. Objectives We tested the potential benefit of diversifying management regimes to increase landscape-level heterogeneity. We hypothesize that different styles of forest management would create a diverse mosaic of forest habitats that would in turn benefit species with various habitat requirements. Methods Forest stands were simulated under business-as-usual management, set-aside (no management) and 12 alternative management regimes. We created virtual landscapes following diversification scenarios to (i) compare the individual performance of management regimes (no diversification), and (ii) test for the management diversification hypothesis at different levels of set-aside. For each virtual landscape, we evaluated habitat availability of six biodiversity indicator species, multispecies habitat availability, and economic values of production. Results Each indicator species responded differently to management regimes, with no single regime being optimal for all species at the same time. Management diversification led to a 30% gain in multispecies habitat availability, relative to business-as-usual management. By selecting a subset of five alternative management regimes with high potential for biodiversity, gains can reach 50%. Conclusions Various alternative management regimes offer diverse habitats for different biodiversity indicator species. Management diversification can yield large gains in multispecies habitat availability with no or low economic cost, providing a potential cost-effective biodiversity tool if the management regimes are thoughtfully selected.
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Boulanger, Yan, Sylvie Gauthier, and Philip J. Burton. "A refinement of models projecting future Canadian fire regimes using homogeneous fire regime zones." Canadian Journal of Forest Research 44, no. 4 (April 2014): 365–76. http://dx.doi.org/10.1139/cjfr-2013-0372.
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Broad-scale fire regime modelling is frequently based on large ecological and (or) administrative units. However, these units may not capture spatial heterogeneity in fire regimes and may thus lead to spatially inaccurate estimates of future fire activity. In this study, we defined homogeneous fire regime (HFR) zones for Canada based on annual area burned (AAB) and fire occurrence (FireOcc), and we used them to model future (2011–2040, 2041–2070, and 2071–2100) fire activity using multivariate adaptive regression splines (MARS). We identified a total of 16 HFR zones explaining 47.7% of the heterogeneity in AAB and FireOcc for the 1959–1999 period. MARS models based on HFR zones projected a 3.7-fold increase in AAB and a 3.0-fold increase in FireOcc by 2100 when compared with 1961–1990, with great interzone heterogeneity. The greatest increases would occur in zones located in central and northwestern Canada. Much of the increase in AAB would result from a sharp increase in fire activity during July and August. Ecozone- and HFR-based models projected relatively similar nationwide FireOcc and AAB. However, very high spatial discrepancies were noted between zonations over extensive areas. The proposed HFR zonation should help providing more spatially accurate estimates of future ecological patterns largely driven by fire in the boreal forest such as biodiversity patterns, energy flows, and carbon storage than those obtained from large-scale multipurpose classification units.
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Neri, Franco M., Francisco J. Pérez-Reche, Sergei N. Taraskin, and Christopher A. Gilligan. "Heterogeneity in susceptible–infected–removed (SIR) epidemics on lattices." Journal of The Royal Society Interface 8, no. 55 (July 14, 2010): 201–9. http://dx.doi.org/10.1098/rsif.2010.0325.
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The percolation paradigm is widely used in spatially explicit epidemic models where disease spreads between neighbouring hosts. It has been successful in identifying epidemic thresholds for invasion, separating non-invasive regimes, where the disease never invades the system, from invasive regimes where the probability of invasion is positive. However, its power is mainly limited to homogeneous systems. When heterogeneity (environmental stochasticity) is introduced, the value of the epidemic threshold is, in general, not predictable without numerical simulations. Here, we analyse the role of heterogeneity in a stochastic susceptible–infected–removed epidemic model on a two-dimensional lattice. In the homogeneous case, equivalent to bond percolation, the probability of invasion is controlled by a single parameter, the transmissibility of the pathogen between neighbouring hosts. In the heterogeneous model, the transmissibility becomes a random variable drawn from a probability distribution. We investigate how heterogeneity in transmissibility influences the value of the invasion threshold, and find that the resilience of the system to invasion can be suitably described by two control parameters, the mean and variance of the transmissibility. We analyse a two-dimensional phase diagram, where the threshold is represented by a phase boundary separating an invasive regime in the high-mean, low-variance region from a non-invasive regime in the low-mean, high-variance region of the parameter space. We thus show that the percolation paradigm can be extended to the heterogeneous case. Our results have practical implications for the analysis of disease control strategies in realistic heterogeneous epidemic systems.
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Arce M., Daniel G. "The Evolution of Heterogeneity in Biodiversity and Environmental Regimes." Journal of Conflict Resolution 44, no. 6 (December 2000): 753–72. http://dx.doi.org/10.1177/0022002700044006003.
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Marcoux, Hélène M., Sarah E. Gergel, and Lori D. Daniels. "Mixed-severity fire regimes: How well are they represented by existing fire-regime classification systems?" Canadian Journal of Forest Research 43, no. 7 (July 2013): 658–68. http://dx.doi.org/10.1139/cjfr-2012-0449.
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Maps depicting historic fire regimes provide critical baselines for sustainable forest management and wildfire risk assessments. However, given our poor understanding of mixed-severity fire regimes, we asked if there may be considerable errors in fire-regime classification systems used to create landscape-level maps. We used dendrochronological field data (fire scars and tree establishment dates) from 20 randomly selected sites in southern British Columbia to evaluate two classification systems (Natural Disturbance Type (NDT) and Historical Natural Fire Regime (HNFR)) used by managers to map fire regimes. We found evidence of mixed-severity fires at 55% of sites. Each classification system made considerable and contrasting errors predicting mixed-severity regimes (relative to field data), and the discrepancies varied with elevation. The NDT system underrepresented low-to-moderate-severity fires at lower elevations, whereas the HNFR system overpredicted their occurrence at higher elevations. Errors are attributed to underlying assumptions about disturbances in the two classification systems, as well as limitations of the research methods used to estimate fire frequency in mixed-severity regimes (i.e., methods more relevant to high- versus low-severity regimes). Ecological heterogeneity created by mixed-severity regimes potentially influences decisions related to conservation, silviculture, wildfire, and fuel mitigation. Thus, understanding underlying assumptions and errors in mapping fire regimes is critical.
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Roos, Williamson, and Bowman. "Is Anthropogenic Pyrodiversity Invisible in Paleofire Records?" Fire 2, no. 3 (July 18, 2019): 42. http://dx.doi.org/10.3390/fire2030042.
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Paleofire studies frequently discount the impact of human activities in past fire regimes. Globally, we know that a common pattern of anthropogenic burning regimes is to burn many small patches at high frequency, thereby generating landscape heterogeneity. Is this type of anthropogenic pyrodiversity necessarily obscured in paleofire records because of fundamental limitations of those records? We evaluate this with a cellular automata model designed to replicate different fire regimes with identical fire rotations but different fire frequencies and patchiness. Our results indicate that high frequency patch burning can be identified in tree-ring records at relatively modest sampling intensities. However, standard methods that filter out fires represented by few trees systematically biases the records against patch burning. In simulated fire regime shifts, fading records, sample size, and the contrast between the shifted fire regimes all interact to make statistical identification of regime shifts challenging without other information. Recent studies indicate that integration of information from history, archaeology, or anthropology and paleofire data generate the most reliable inferences of anthropogenic patch burning and fire regime changes associated with cultural changes.
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Miller, Carol, and Dean L. Urban. "Interactions between forest heterogeneity and surface fire regimes in the southern Sierra Nevada." Canadian Journal of Forest Research 29, no. 2 (February 1, 1999): 202–12. http://dx.doi.org/10.1139/x98-188.
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Fire is a major agent of spatial pattern formation in forests, as it creates a mosaic of burned and unburned patches. While most research has focused on landscape-level patterns created by crown fires, millions of hectares of forests in North America are subject to surface fire regimes. A spatially explicit forest gap model developed for the Sierra Nevada was used to evaluate the influence of surface fire regimes on the heterogeneity of forest structure and composition within forest stands. Forest pattern was evaluated for a wide range of topographic positions in Sequoia National Park, California, to determine if repeated surface fires amplify existing spatial patterns. The spatial heterogeneity of some forest characteristics increased under a simulated fire regime relative to scenarios without fire. Although a distinct and regular fire-generated spatial pattern was not detected with an analysis of spatial autocorrelation, simulated surface fires did alter the spatial heterogeneity within a forest stand, primarily by degrading a regular structure that is imposed by competition for light in the absence of fire. The interaction between surface fires and forest pattern may be qualitatively different from that which occurs in forests subject to crown fires. As such, what has been learned about forests dominated by crown fires may not apply to forests subject to surface fire regimes.
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Gapontsev, V. L., Valerie M. Koloskov, and M. G. Gapontseva. "Generalization of Fisher Model for Periodically Non-Uniform Grain Boundary." Defect and Diffusion Forum 277 (April 2008): 213–20. http://dx.doi.org/10.4028/www.scientific.net/ddf.277.213.
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The problem of grain boundary diffusion for a case of boundary grain with periodic heterogeneity diffusion properties is considered. Dependence of Laplace transform images of impurity concentration on various diffusion conductivity places is built. The dimensionless parameters, forming the system of grain boundary diffusion regimes are determined. The space (ln x,lnt,1/T) is divided into areas in which the ratio ln ln ~ ln ln ( / ) ln eff o C r x−k t− Q RT − A is maintained, when the parameters of diffusion regime are constant. The values of parameters , , , eff o r k Q A fully specify the diffusion regimes. On this base the new concept for the definition of grain boundary diffusion regimes is carried out and the method for construction of simplified tracer concentration profile is proposed.
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Malard, Florian, Alain Mangin, Urs Uehlinger, and J. V. Ward. "Thermal heterogeneity in the hyporheic zone of a glacial floodplain." Canadian Journal of Fisheries and Aquatic Sciences 58, no. 7 (July 1, 2001): 1319–35. http://dx.doi.org/10.1139/f01-079.
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We examined the thermal regime of surface and hyporheic waters at three kryal sites and four krenal streams within the channel network of a glacial floodplain. Temperature was continuously measured for 1 year in the surface stream and at sediment depths of 30 and 80 cm. The vertical pattern of water temperature was strongly influenced by the direction and intensity of surface water groundwater exchanges. At sites characterized by strong downwelling of surface waters, the thermal regimes of surface and hyporheic waters were virtually identical. In contrast, inputs of groundwater substantially increased mean summer temperatures in the hyporheic zone of the main kryal channel, decreased summer temperatures in the hyporheic zone of krenal streams, and elevated hyporheic temperatures of all stream types during winter. Groundwater from different sources had dramatically different effects on the seasonal regime of temperature in the hyporheic zone. Inflow of shallow alluvial groundwater had minimal effects on seasonal patterns of hyporheic temperature, whereas upwelling from deep alluvial and hillslope aquifers resulted in significant time lags and differences in seasonal amplitudes between surface and hyporheic temperatures. The unexpectedly high thermal heterogeneity of hyporheic waters presumably sustains biodiversity and stimulates ecosystem processes in this glacial floodplain.
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Poghosyan, Tigran, and Subal C. Kumbhakar. "Heterogeneity of technological regimes and banking efficiency in former socialist economies." Journal of Productivity Analysis 33, no. 1 (October 10, 2009): 19–31. http://dx.doi.org/10.1007/s11123-009-0157-3.
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Seguin, Charles, and David Rigby. "National Crimes: A New National Data Set of Lynchings in the United States, 1883 to 1941." Socius: Sociological Research for a Dynamic World 5 (January 2019): 237802311984178. http://dx.doi.org/10.1177/2378023119841780.
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Historians are increasingly studying lynching outside of the American Southeast, but sociologists have been slow to follow. We introduce a new public data set that extends existing data on lynching victims to cover the contiguous United States from 1883 to 1941. These data confirm that lynching was a heterogeneous practice across the United States. We differentiate between three different regimes over this period: a Wild West regime, characterized mostly by the lynching of whites in areas with weak state penetration; a slavery regime, found in former slave states, characterized mostly by the lynching of blacks; and a third minor regime, characterized by the lynching of Mexican nationals mostly along the Texas-Mexico border. We also note great variability at the county level in the extent of lynching. By contrast, we find very little state-level variability in lynching once local and regional regimes are considered. We discuss the implications of local and regional heterogeneity for quantitative lynching research using these data.
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Joubert-Van der Merwe, Lize, and James S. Pryke. "Is cattle grazing more important than landscape heterogeneity for grasshoppers in Afromontane grassland?" Journal of Orthoptera Research 27, no. 1 (June 12, 2018): 13–21. http://dx.doi.org/10.3897/jor.27.15027.
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Overgrazing is a major driver of habitat degradation, especially in southern Africa. Although grasshoppers are adapted to and benefit from natural disturbances, such as grazing by indigenous game and burning, we do not know how they respond to heavy cattle grazing, and how this response interacts with different fire regimes. We also do not know whether grasshoppers respond principally to these disturbances, to changes in the vegetation layer, or to larger landscape attributes (e.g. elevation). We addressed these questions in the topographically heterogeneous Central Midlands of KwaZulu-Natal Province, South Africa. We compared grasshopper assemblages among sites differing in grazing intensity (light, moderate and heavy), fire regime, rocky outcrops and vegetation structure, and attributes of landscape heterogeneity. The local environment (rocky outcrops, bare ground cover, grass height and total vegetation cover) was more important than landscape attributes for all measures of diversity. Grasshopper species richness was best explained by grazing intensity, with the specific response determined by fire regime. Greatest species richness was consistently recorded in heavily-grazed grassland. Thus, we found no evidence in support of the Intermediate Disturbance Hypothesis. Grasshopper assemblage composition of areas with light grazing was different from those with heavy grazing, but areas with light grazing were similar to those with moderate grazing under all fire regimes. Different suites of grasshopper species were adapted to changes in the local environment, with greatest diversity (Shannon H’) associated with elevated levels of bare ground and sparse vegetation cover. The greatest proportion of rare, endemic and sensitive grasshoppers (incl. Lentula minuta, Machaeridia conspersa and Qachasia fastigiata) was associated with a greater proportion of vegetation cover. The sensitivity of grasshopper assemblages to fire-grazing interactions, and the habitat requirements of different suites of species necessitates consideration of different types (fire and grazing) as well as levels of disturbances when adjusting management practices. We recommend that conservation of rare, endemic and sensitive grasshoppers should be prioritized, as these are most vulnerable to local extirpation.
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Green, Christopher, and Jonathan Ennis-King. "Steady Flux Regime During Convective Mixing in Three-Dimensional Heterogeneous Porous Media." Fluids 3, no. 3 (August 14, 2018): 58. http://dx.doi.org/10.3390/fluids3030058.
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Density-driven convective mixing in porous media can be influenced by the spatial heterogeneity of the medium. Previous studies using two-dimensional models have shown that while the initial flow regimes are sensitive to local permeability variation, the later steady flux regime (where the dissolution flux is relatively constant) can be approximated with an equivalent anisotropic porous media, suggesting that it is the average properties of the porous media that affect this regime. This work extends the previous results for two-dimensional porous media to consider convection in three-dimensional porous media. Through the use of massively parallel numerical simulations, we verify that the steady dissolution rate in the models of heterogeneity considered also scales as k v k h in three dimensions, where k v and k h are the vertical and horizontal permeabilities, respectively, providing further evidence that convective mixing in heterogeneous models can be approximated with equivalent anisotropic models.
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Kang, Zhixin. "An investigation on impacts of structural changes in stocks’ past returns on financial analysts’ earnings forecasting rationality." Journal of Capital Markets Studies 3, no. 2 (November 11, 2019): 188–202. http://dx.doi.org/10.1108/jcms-06-2019-0033.
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Purpose The purpose of this paper is to test whether financial analysts’ rationality in making stocks’ earnings forecasts is homogenous or not across different information regimes in stocks’ past returns. Design/methodology/approach By treating stocks’ past returns as the information variable in this study, the authors employ a threshold regression model to capture and test threshold effects of stocks’ past returns on financial analysts’ rationality in making earnings forecasts in different information regimes. Findings The results show that three significant structural breaks and four respective information regimes are identified in stocks’ past returns in the threshold regression model. Across the four different information regimes, financial analysts react to stocks’ past returns quite differently when making one-quarter ahead earnings forecasts. Furthermore, the authors find that financial analysts are only rational in a certain information regime of stocks’ past returns depending on a certain return-window such as one-quarter, two-quarter or four-quarter time period. Originality/value This study is different from those in the existing literature by arguing that there could exist heterogeneity in financial analysts’ rationality in making earnings forecasts when using stocks’ past returns information. The finding that financial analysts react to stocks’ past returns differently in the different information regimes of past returns adds value to the research on financial analysts’ rationality.
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Baker, William L. "Effect of scale and spatial heterogeneity on fire-interval distributions." Canadian Journal of Forest Research 19, no. 6 (June 1, 1989): 700–706. http://dx.doi.org/10.1139/x89-109.
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The distribution of forest-fire intervals has been characterized by fitting statistical distributions, such as that of Weibull. The parameters of fitted distributions can then be used to compare fire regimes. Fire-interval distributions for the 187-year presettlement fire history record in the Boundary Waters Canoe Area, Minnesota, were analyzed using reconstructed "fire-year" maps. Distributions were determined for sampling units at five spatial scales, from about 25 000 to 400 000 ha. Fire-interval distributions varied from positively to negatively skewed, but for most units the Weibull distribution fit significantly. The distributions varied spatially, and cluster analysis suggested that three fire regions, each containing a relatively homogeneous fire regime, could be identified. The sources of this spatial variation are unknown. There was less variation between scales within a fire region than between fire regions. This contrasts with a previous finding, using the same fire-history data, that scale substantially affects observed landscape age-class distribution. This disparity arises because landscape age-class distributions may fluctuate even if fire-interval distributions do not fluctuate. Reconstruction of fire-interval distributions requires historical data; landscape age-class distributions at an instant in time are insufficient.
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Niu, Ben J. "Equilibria and Location Choice in Corporate Tax Regimes." Public Finance Review 47, no. 2 (September 13, 2017): 433–58. http://dx.doi.org/10.1177/1091142117729434.
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This article considers the impact of preferential, base-specific taxation on equilibrium revenues. While policy makers have argued that it generates a prisoner’s dilemma result, there is mixed support in the academic literature. Using a more plausible model with asymmetric base elasticities and heterogeneity of both firms and countries, I find that preferential taxation can generate greater revenues if countries exhibit sufficient productivity and/or population asymmetry. It is also less distortionary except in cases where moving costs are fully deductible. Allowing for noncorrelated, cross-country profits is the key factor as it generates base expansion effects.
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Akbar, Ruzbeh, Daniel J. Short Gianotti, Kaighin A. McColl, Erfan Haghighi, Guido D. Salvucci, and Dara Entekhabi. "Estimation of Landscape Soil Water Losses from Satellite Observations of Soil Moisture." Journal of Hydrometeorology 19, no. 5 (May 1, 2018): 871–89. http://dx.doi.org/10.1175/jhm-d-17-0200.1.
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Abstract This study presents an observation-driven technique to delineate the dominant boundaries and temporal shifts between different hydrologic regimes over the contiguous United States (CONUS). The energy- and water-limited evapotranspiration regimes as well as percolation to the subsurface are hydrologic processes that dominate the loss of stored water in the soil following precipitation events. Surface soil moisture estimates from the NASA Soil Moisture Active Passive (SMAP) mission, over three consecutive summer seasons, are used to estimate the soil water loss function. Based on analysis of the rates of soil moisture dry-downs, the loss function is the conditional expectation of negative increments in the soil moisture series conditioned on soil moisture itself. An unsupervised classification scheme (with cross validation) is then implemented to categorize regions according to their dominant hydrological regimes based on their estimated loss functions. An east–west divide in hydrologic regimes over CONUS is observed with large parts of the western United States exhibiting a strong water-limited evapotranspiration regime during most of the times. The U.S. Midwest and Great Plains show transitional behavior with both water- and energy-limited regimes present. Year-to-year shifts in hydrologic regimes are also observed along with regional anomalies due to moderate drought conditions or above-average precipitation. The approach is based on remotely sensed surface soil moisture (approximately top 5 cm) at a resolution of tens of kilometers in the presence of soil texture and land cover heterogeneity. The classification therefore only applies to landscape-scale effective conditions and does not directly account for deeper soil water storage.
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Copeland, Brian R., and M. Scott Taylor. "Trade, Tragedy, and the Commons." American Economic Review 99, no. 3 (May 1, 2009): 725–49. http://dx.doi.org/10.1257/aer.99.3.725.
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We develop a theory of resource management where the degree to which countries escape the tragedy of the commons, and hence the de facto property rights regime, is endogenously determined. Three forces determine success or failure in resource management: the regulator's enforcement power, the extent of harvesting capacity, and the ability of the resource to generate competitive returns without being extinguished. The model can explain heterogeneity across countries and resources in the effectiveness of resource management, and it predicts that changes in prices, population, and technology can cause transitions to better or worse management regimes. (JEL P14, Q21, Q22, Q23, Q32)
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Okasinski, John S., Ilya A. Shkrob, Andrew Chuang, Marco-Tulio Fonseca Rodrigues, Abhi Raj, Dennis W. Dees, and Daniel P. Abraham. "In situ X-ray spatial profiling reveals uneven compression of electrode assemblies and steep lateral gradients in lithium-ion coin cells." Physical Chemistry Chemical Physics 22, no. 38 (2020): 21977–87. http://dx.doi.org/10.1039/d0cp04436a.
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In situ X-ray diffraction profilometry reveals radially nonuniform compression of the electrode assembly leading to large lateral heterogeneity of lithium intercalation and plating in the standard Li-ion coin cells in fast charge regimes.
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Brook, Barry W., and Peter J. Whitehead. "Sustainable harvest regimes for magpie geese (Anseranas semipalmata) under spatial and temporal heterogeneity." Wildlife Research 32, no. 5 (2005): 459. http://dx.doi.org/10.1071/wr02104.
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We developed a population model of magpie geese in the Northern Territory that considered spatial and temporal variation and related sources of uncertainty, building on previous analyses of the plausible rates of increase for this species. The model was used to explore realistic limits to recreational and indigenous harvest and to examine productive, yet risk-averse, management regimes for long-term sustainability. Harvest strategies based on a proportional off-take provided similar yields to a fixed quota system, but resulted in a reduced risk of substantial population decline. Moreover, higher harvests could be supported in model systems that incorporated dispersal phenomena consistent with patterns suggested by the observed distributional and abundance patterns. However, irrespective of harvest strategy and spatial structure, off-take at the levels implied in previously published analyses are clearly unsustainable. These results illustrate the desirability of matching the design of management systems to the heterogeneity of population processes. Management regimes that fail to take account of spatial and temporal heterogeneity could damage the interests of important stakeholder groups and potentially imperil the future viability of the species. However, the costs of disaggregated management systems may be substantial and benefits of investment in them need to be clearly demonstrated. Gaining better appreciation of spatial variation in harvests should be given high priority.
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Yocom-Kent, Larissa L., Peter Z. Fulé, Windy A. Bunn, and Eric G. Gdula. "Historical high-severity fire patches in mixed-conifer forests." Canadian Journal of Forest Research 45, no. 11 (November 2015): 1587–96. http://dx.doi.org/10.1139/cjfr-2015-0128.
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Two ends of the fire regime spectrum are a frequent low-intensity fire regime and an infrequent high-intensity fire regime, but intermediate fire regimes combine high- and low-severity fire over space and time. We used fire-scar and tree-age data to reconstruct fire regime attributes of mixed-conifer and aspen forests in the North Rim area of Grand Canyon National Park, with a goal of estimating patch sizes of historical high-severity fire and comparing them with modern patch sizes. We used three methods based on (i) aspen groves, (ii) even-aged stands, and (iii) inverse distance weighting, to estimate occurrence and patch sizes of historical high-severity fire. Evidence of high-severity fire was common in the 1800s, and high-severity fire years were associated with drought. High-severity fire patch sizes likely ranged from 10−1 to 102 ha. However, the forest is quite young, and we cannot rule out a historical large high-severity fire that could have reinitiated much of the 1400 ha study area. Fire scars, which are indicative of low-severity fire, were also common. Historical fire was likely heterogeneous across the landscape. Maintaining heterogeneity of fire severity, size, and frequency would promote heterogeneity of forest structure and composition and resilience to future disturbances.
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Ivanov, A. I., Zh A. Ivanova, and V. I. Dubovitskaya. "The influence of landscape conditions on the properties of soil cover of arable land on a gentle slope lake-glacial plains." Rossiiskaia selskokhoziaistvennaia nauka, no. 2 (April 9, 2019): 39–43. http://dx.doi.org/10.31857/s2500-26272019239-43.
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In order to lay the landscape experience, the soil cover of the agro-landscape on the gentle slope of the lake-glacial plain was studied and the factors and parameters of spatial differentiation of some physical, physico-chemical and agrochemical properties were established. The different degree of differentiation of individual properties associated with the characteristics of soil-ing rocks, geochemical regimes and the nature of anthropogenic impact is established. Significant heterogeneity in the power of eluvial horizons, the degree of development of the gley process, the structural state, the content of organic matter, nitrogen and moderate- granulometric composition, physico chemical properties and nutritional regime. The main factor of variation of soil properties in the agricultural landscape is heterogeneity of soil-forming rocks, estimated in terms of physical, chemical and agrochemical properties in 19-59 %. Natural and anthropogenic soil formation process reduced the average coefficient of variation of these properties within the arable layer by 2.6 times (from 36% to 14 %). The factor of increasing the heterogeneity of a number of agrochemical properties by 1.3-1.9 times in the tranzitno-eluvial facies was planar erosion, in the eluvial facies by 3 times uneven application of organic fertilizers.
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Kidando, Emmanuel, Ren Moses, Thobias Sando, and Eren Erman Ozguven. "An application of Bayesian multilevel model to evaluate variations in stochastic and dynamic transition of traffic conditions." Journal of Modern Transportation 27, no. 4 (October 19, 2019): 235–49. http://dx.doi.org/10.1007/s40534-019-00199-2.
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Abstract This study seeks to investigate the variations associated with lane lateral locations and days of the week in the stochastic and dynamic transition of traffic regimes (DTTR). In the proposed analysis, hierarchical regression models fitted using Bayesian frameworks were used to calibrate the transition probabilities that describe the DTTR. Datasets of two sites on a freeway facility located in Jacksonville, Florida, were selected for the analysis. The traffic speed thresholds to define traffic regimes were estimated using the Gaussian mixture model (GMM). The GMM revealed that two and three regimes were adequate mixture components for estimating the traffic speed distributions for Site 1 and 2 datasets, respectively. The results of hierarchical regression models show that there is considerable evidence that there are heterogeneity characteristics in the DTTR associated with lateral lane locations. In particular, the hierarchical regressions reveal that the breakdown process is more affected by the variations compared to other evaluated transition processes with the estimated intra-class correlation (ICC) of about 73%. The transition from congestion on-set/dissolution (COD) to the congested regime is estimated with the highest ICC of 49.4% in the three-regime model, and the lowest ICC of 1% was observed on the transition from the congested to COD regime. On the other hand, different days of the week are not found to contribute to the variations (the highest ICC was 1.44%) on the DTTR. These findings can be used in developing effective congestion countermeasures, particularly in the application of intelligent transportation systems, such as dynamic lane-management strategies.
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Gong, Sanqiang, Xuejie Jin, Lijuan Ren, Yehui Tan, and Xiaomin Xia. "Unraveling Heterogeneity of Coral Microbiome Assemblages in Tropical and Subtropical Corals in the South China Sea." Microorganisms 8, no. 4 (April 21, 2020): 604. http://dx.doi.org/10.3390/microorganisms8040604.
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Understanding the coral microbiome is critical for predicting the fidelity of coral symbiosis with growing surface seawater temperature (SST). However, how the coral microbiome will respond to increasing SST is still understudied. Here, we compared the coral microbiome assemblages among 73 samples across six typical South China Sea coral species in two thermal regimes. The results revealed that the composition of microbiome varied across both coral species and thermal regimes, except for Porites lutea. The tropical coral microbiome displayed stronger heterogeneity and had a more un-compacted ecological network than subtropical coral microbiome. The coral microbiome was more strongly determined by environmental factors than host specificity. γ- (32%) and α-proteobacteria (19%), Bacteroidetes (14%), Firmicutes (14%), Actinobacteria (6%) and Cyanobacteria (2%) dominated the coral microbiome. Additionally, bacteria inferred to play potential roles in host nutrients metabolism, several keystone bacteria detected in human and plant rhizospheric microbiome were retrieved in explored corals. This study not only disentangles how different host taxa and microbiome interact and how such an interaction is affected by thermal regimes, but also identifies previously unrecognized keystone bacteria in corals, and also infers the community structure of coral microbiome will be changed from a compacted to an un-compacted network under elevated SST.
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Allen, Iris, Sophan Chhin, and Jianwei Zhang. "Fire and Forest Management in Montane Forests of the Northwestern States and California, USA." Fire 2, no. 2 (April 3, 2019): 17. http://dx.doi.org/10.3390/fire2020017.
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We reviewed forest management in the mountainous regions of several northwestern states and California in the United States and how it has impacted current issues facing these forests. We focused on the large-scale activities like fire suppression and logging which resulted in landscape level changes. We divided the region into two main forests types; wet, like the forests in the Pacific Northwest, and dry, like the forests in the Sierra Nevada and Cascade ranges. In the wet forests, the history of intensive logging shaped the current forest structure, while fire suppression played a more major role in the dry forests. Next, we looked at how historical management has influenced new forest management challenges, like catastrophic fires, decreased heterogeneity, and climate change. We then synthesized what current management actions are performed to address these issues, like thinning to reduce fuels or improve structural heterogeneity, and restoration after large-scale disturbances. Lastly, we touch on some major policies that have influenced changes in management. We note a trend towards ecosystem management that considers a forest’s historical disturbance regime. With expected climate induced changes in fire frequency, it is suggested that fuel treatments be implemented in dry forests to ensure an understory fire regime is restored in these forest systems. With respect to wet forests in this region, it is suggested that there is still a place for stand-replacing fire regimes. However, these forests will require structural changes incorporating heterogeneity to improve their resiliency and health.
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Kirkpatrick, J. B. "Collateral benefit: unconscious conservation of threatened plant species." Australian Journal of Botany 55, no. 3 (2007): 221. http://dx.doi.org/10.1071/bt06104.
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In Europe, the conservation of rare or threatened plant species (ROTS) largely involves the manipulation of anthropogenic disturbance regimes rather than the mitigation of human-induced threatening processes, as has been the case in Australia. In Tasmania, there are many ROTS, especially those of the depleted and stock-grazed grasslands and grassy woodlands, which survive because, unconscious of the needs of ROTS, people have disturbed land in ways that suit their life-cycle requirements. Such species are found in quarries, in borrow pits, in scrapes, on roadsides, on track edges, on old roads, under introduced trees, in heavily grazed native pastures, in regenerating clearfell coupes and on mown ground. They are disturbance-dependent species, usually with poor competitive abilities. Many cannot survive stock-grazing. Unconscious conservation of these species needs to become conscious, in the European manner. Spatial heterogeneity in disturbance regimes is important for maintaining this set of species, whereas temporal heterogeneity is likely to lead to their doom.
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Miller, Carol, and Dean L. Urban. "Erratum: Interactions between forest heterogeneity and surface fire regimes in the southern Sierra Nevada." Canadian Journal of Forest Research 29, no. 5 (May 1, 1999): 646. http://dx.doi.org/10.1139/x98-188e.
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Chiao, L. Y., and Q. Liu. "Dependence of sandpile avalanche frequency–size distribution on coverage extent and compactness of embedded toppling threshold heterogeneity: implications for the variation of Gutenberg–Richter <i>b</i> value." Nonlinear Processes in Geophysics 21, no. 6 (December 5, 2014): 1185–93. http://dx.doi.org/10.5194/npg-21-1185-2014.
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Abstract. The effects of the spatiotemporal evolution of failure threshold heterogeneity on the dynamics of fault criticality, and thus on regional seismogenesis, have attracted strong interest in the field of regional seismotectonics. The heterogeneity might be a manifestation of the macroscopic distribution and multiscale strength variation of asperities, the distinct regional stress level, and (microscopically) heterogeneous fault surface roughness or friction regimes. In this study, rather than attempting to mimic the complex microscale slipping physics on a fault surface, sandpile cellular automata were implemented with a straightforward toppling rule. The objective is to examine the influence of distinct configurations of the embedded heterogeneous toppling threshold field on the global system avalanche event statistics. The examination results revealed that increasing the coverage extent and decreasing the compactness of the heterogeneous failure threshold, rather than the magnitude, range of contrast, diversity, or the geometric configuration of the threshold heterogeneity, leads to a systematic increase in the scaling exponent of the avalanche event power law statistics, implying the importance of mutual interaction among toppling sites with distinct thresholds. For tectonic provinces with differing stress regimes evolving spatio temporally, it is postulated that the distinct extent and compactness of the heterogeneous failure threshold are critical factors that manifest in the reported dynamic variations of seismicity scaling.
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Chazette, Patrick, Alexandre Baron, and Cyrille Flamant. "Mesoscale spatio-temporal variability of airborne lidar-derived aerosol properties in the Barbados region during EUREC<sup>4</sup>A." Atmospheric Chemistry and Physics 22, no. 2 (January 25, 2022): 1271–92. http://dx.doi.org/10.5194/acp-22-1271-2022.
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Abstract. From 23 January to 13 February 2020, 20 ATR-42 scientific flights were conducted in the framework of the EUREC4A field campaign over the tropical Atlantic, off the coast of Barbados (13∘30′ N, −58∘30′ W). By means of a sideway-pointing lidar, these flights allowed us to retrieve the optical properties of the aerosols found in the sub-cloud layer and below the trade wind inversion. Two distinct periods with significant aerosol contents were identified in relationship with the so-called trade wind and tropical regimes, respectively. For these two regimes, mixings of two air mass types encompassing dust and carbonaceous aerosols have been highlighted. Both were mainly from West Africa with similar optical contributions and linked to dust uptake above Sahara and biomass burning between Guinea-Bissau and Côte d'Ivoire. In the tropical transport regime, the wind within the planetary boundary layer is stronger and favours a contribution of marine aerosols (sulfate and sea salt aerosol components) in shallower aerosol layers than for the trade wind transport regime. The latter is responsible for advecting dust–biomass-burning-aerosol mixtures in the deeper, well-mixed layer, in part due to the complex interactions of the easterly flow from West Africa with mid-latitude dynamics. The aerosol vertical structures appear to be well reproduced using atmospheric composition reanalyses from CAMS when comparing with lidar-derived vertical profiles. The competition between the two types of transport regimes leads to strong heterogeneity in the optical properties of the horizontal aerosol field. Our study highlights the transport regime under which a significant mixture of dust and biomass burning aerosols from West Africa can be observed over the Caribbean and Barbados in particular, namely the trade wind regime.
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Tewary, Vivek. "Combined effects of homogenization and singular perturbations: A bloch wave approach." Networks & Heterogeneous Media 16, no. 3 (2021): 427. http://dx.doi.org/10.3934/nhm.2021012.
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<p style='text-indent:20px;'>In this work, we study Bloch wave homogenization of periodically heterogeneous media with fourth order singular perturbations. We recover different homogenization regimes depending on the relative strength of the singular perturbation and length scale of the periodic heterogeneity. The homogenized tensor is obtained in terms of the first Bloch eigenvalue. The higher Bloch modes do not contribute to the homogenization limit. The main difficulty is the presence of two parameters which requires us to obtain uniform bounds on the Bloch spectral data in various regimes of the parameter.</p>
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Mysin, I. E., and A. V. Chizhov. "The Role of Geterogeneity in Synchronization of Spiking Neural Networks." Mathematical Biology and Bioinformatics 13, no. 2 (December 11, 2018): 490–506. http://dx.doi.org/10.17537/2018.13.490.
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The diversity and heterogeneity of neurons and synapses is an important factor in the functioning of the brain. In our work, we investigated the role of heterogeneity of neural populations in the occurrence of synchronous modes in a network connected by exciting links in the presence of an external exciting input. Using Monte-Carlo modeling and the semi-analytical modeling the distribution of the refractory density of neuron integrators and Hodgkin – Huxley neurons, we showed that there is a range of parameters for the stimulating current and the strength of connections in the population where the effects of neuronal heterogeneity on the threshold or on the stimulating current are opposite. For large values of synaptic weights and subthreshold values of the exciting current, heterogeneity contributes to the emergence of a synchronous mode in the neural network, while at the same time reducing the coupling strength and increasing the exciting current. The heterogeneity reduces the tendency of the neural network to synchronize. The results obtained make it possible to reconcile the known data on the effects of heterogeneity in the regulation of the synchronous regimes arising in the neural ensembles of the brain.
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Nygren, Lennart, Sue White, and Ingunn T. Ellingsen. "Investigating Welfare Regime Typologies: Paradoxes, Pitfalls and Potentialities in Comparative Social Work Research." Social Policy and Society 17, no. 4 (June 13, 2018): 665–77. http://dx.doi.org/10.1017/s1474746418000167.
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The article reviews the relevance and methodological utility of welfare regime typologies for the study of professional sense-making in social work with families. Focus groups were carried out with social workers in European and Latin American countries representing four different policy regimes. A case vignette was used to elicit social workers’ descriptions of how welfare policy may influence how they understand their work task and the notion of family. The research team identified methodological challenges of general relevance in similar policy-practice studies. There were paradoxes in terms of homogeneity on the regime level vs. heterogeneity within and between national services. Pitfalls appeared in the selection of regime-typical cases, language/cultural barriers, and in deciding organisational level. The article shows that welfare typologies have potentialities in that they may provide a helpful analytical basis for theoretical and practical reasoning in which syntheses between policy and practice can be explored, discussed and challenged.
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Chapman, Susan A., Joanne Spetz, Jessica Lin, Krista Chan, and Laura A. Schmidt. "Capturing Heterogeneity in Medical Marijuana Policies: A Taxonomy of Regulatory Regimes Across the United States." Substance Use & Misuse 51, no. 9 (May 18, 2016): 1174–84. http://dx.doi.org/10.3109/10826084.2016.1160932.
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Tang, Q., W. Kurtz, O. S. Schilling, P. Brunner, H. Vereecken, and H. J. Hendricks Franssen. "The influence of riverbed heterogeneity patterns on river-aquifer exchange fluxes under different connection regimes." Journal of Hydrology 554 (November 2017): 383–96. http://dx.doi.org/10.1016/j.jhydrol.2017.09.031.
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Tahvonen, Olli, Janne Rämö, and Mikko Mönkkönen. "Economics of mixed-species forestry with ecosystem services." Canadian Journal of Forest Research 49, no. 10 (October 2019): 1219–32. http://dx.doi.org/10.1139/cjfr-2018-0514.
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The Faustmann–Hartman setup is widely established for specifying the economics of forest values besides timber, but it is criticized as restrictive for capturing diversity values. We show that extending the model to cover diversity attributes, i.e., mixed species and internal heterogeneity within species, is not enough to overcome these restrictions. Additionally, it is necessary to extend forest harvesting regimes to cover thinning, continuous cover forestry, and the management of commercially useless trees. Restrictions in the Faustmann–Hartman setup are first shown analytically with optimized thinning but without tree size structures. The empirical significance of these findings is shown by a model that includes four tree species, tree size structures, an extended set of forest management activities, a detailed description of harvesting costs, and a measure for stand diversity as a key factor behind ecosystem services. We show how an optimal harvesting regime, net revenues, wood output, and stand diversity depend on model flexibility, economic parameters, and the valuation of ecosystem services. In a setup allowing flexible management regimes, the costs of reaching a specified level of ecosystem services are negligible compared with those of the Faustmann–Hartman specification.
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Lawes, Michael J., Brett P. Murphy, Alaric Fisher, John C. Z. Woinarski, Andrew C. Edwards, and Jeremy Russell-Smith. "Small mammals decline with increasing fire extent in northern Australia: evidence from long-term monitoring in Kakadu National Park." International Journal of Wildland Fire 24, no. 5 (2015): 712. http://dx.doi.org/10.1071/wf14163.
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Small mammal (<2 kg) numbers have declined dramatically in northern Australia in recent decades. Fire regimes, characterised by frequent, extensive, late-season wildfires, are implicated in this decline. Here, we compare the effect of fire extent, in conjunction with fire frequency, season and spatial heterogeneity (patchiness) of the burnt area, on mammal declines in Kakadu National Park over a recent decadal period. Fire extent – an index incorporating fire size and fire frequency – was the best predictor of mammal declines, and was superior to the proportion of the surrounding area burnt and fire patchiness. Point-based fire frequency, a commonly used index for characterising fire effects, was a weak predictor of declines. Small-scale burns affected small mammals least of all. Crucially, the most important aspects of fire regimes that are associated with declines are spatial ones; extensive fires (at scales larger than the home ranges of small mammals) are the most detrimental, indicating that small mammals may not easily escape the effects of large and less patchy fires. Notwithstanding considerable management effort, the current fire regime in this large conservation reserve is detrimental to the native mammal fauna, and more targeted management is required to reduce fire size.
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Stich, Michael, Christian Punckt, Carsten Beta, and Harm Hinrich Rotermund. "Control of spatiotemporal chaos in catalytic CO oxidation by laser-induced pacemakers." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 366, no. 1864 (August 2, 2007): 419–26. http://dx.doi.org/10.1098/rsta.2007.2099.
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Control of spatiotemporal chaos is achieved in the catalytic oxidation of CO on Pt(110) by localized modification of the kinetic properties of the surface chemical reaction. In the experiment, a small temperature heterogeneity is created on the surface by a focused laser beam. This heterogeneity constitutes a pacemaker and starts to emit target waves. These waves slowly entrain the medium and suppress the spatiotemporal chaos that is present in the absence of control. We compare this experimental result with a numerical study of the Krischer–Eiswirth–Ertl model for CO oxidation on Pt(110). We confirm the experimental findings and identify regimes where complete and partial controls are possible.
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Tiemann, Guido. "The Nationalization of political parties and party systems in post-communist Eastern Europe." Communist and Post-Communist Studies 45, no. 1-2 (March 2012): 77–89. http://dx.doi.org/10.1016/j.postcomstud.2012.02.009.
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Party system nationalization is a crucial aspect of political competition. The territories of Eastern Europe have often been characterized by outstanding levels of territorial heterogeneity. However, during and after World War II ethnic cleansing and forced migration resulted in more homogeneous nation states, and these trends were significantly reinforced by bureaucratic, centralized communist rule. I present a systematic empirical assessment of party and party system homogeneity or heterogeneity in post-communist Eastern Europe and will discuss some major macrosociological and institutional factors determining the degree of party and party system nationalization such as the political consequences of social diversity and political cleavages, legacies of the communist regimes, electoral systems, and federalism.
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Sessoms, David A., Irmgard Bischofberger, Luca Cipelletti, and Véronique Trappe. "Multiple dynamic regimes in concentrated microgel systems." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 367, no. 1909 (December 28, 2009): 5013–32. http://dx.doi.org/10.1098/rsta.2009.0178.
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We investigate dynamical heterogeneities in the collective relaxation of a concentrated microgel system, for which the packing fraction can be conveniently varied by changing the temperature. The packing fraction-dependent mechanical properties are characterized by a fluid–solid transition, where the system properties switch from a viscous to an elastic low-frequency behaviour. Approaching this transition from below, we find that the range ξ of spatial correlations in the dynamics increases. Beyond this transition, ξ reaches a maximum, extending over the entire observable system size of approximately 5 mm. Increasing the packing fraction even further leads to a second transition, which is characterized by the development of large zones of lower and higher dynamical activity that are well separated from each other; the range of correlation decreases at this point. This striking non-monotonic dependence of ξ on volume fraction is reminiscent of the behaviour recently observed at the jamming/rigidity transition in granular systems. We identify this second transition as the transition to ‘squeezed’ states, where the constituents of the system start to exert direct contact forces on each other, such that the dynamics becomes increasingly determined by imbalanced stresses. Evidence of this transition is also found in the frequency dependence of the storage and loss moduli, which become increasingly coupled as direct friction between the particles starts to contribute to the dissipative losses within the system. To our knowledge, our data provide the first observation of a qualitative change in dynamical heterogeneity as the dynamics switches from purely thermally driven to stress driven.
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Weaver, Christopher P. "Coupling between Large-Scale Atmospheric Processes and Mesoscale Land–Atmosphere Interactions in the U.S. Southern Great Plains during Summer. Part I: Case Studies." Journal of Hydrometeorology 5, no. 6 (December 1, 2004): 1223–46. http://dx.doi.org/10.1175/jhm-396.1.
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Abstract This paper is Part I of a two-part study that uses high-resolution Regional Atmospheric Modeling System (RAMS) simulations to investigate mesoscale land–atmosphere interactions in the summertime U.S. Southern Great Plains. The focus is on the atmospheric dynamics associated with mesoscale heterogeneity in the underlying surface fluxes: how shifts in meteorological regimes modulate these diurnal, mesoscale processes, and their overall impact at larger scales and over multiple diurnal cycles. Part I examines individual case study time periods drawn from the simulations that illustrate general points about the key land–atmosphere interactions. The main findings are as follows: The mesoscale processes are embedded within a synoptic-scale organization that controls the background meteorological regime at a given location. During the clear, dry days in the simulated months, heterogeneity in the surface fluxes forces strong, lower-tropospheric, mesoscale circulations that exhibit a characteristic dynamical life cycle over diurnal time scales. In general, the background large-scale flow does not affect the overall intensity of these coherent roll structures, though strong large-scale subsidence can sometimes dampen them. In addition, depending on the thermodynamic profile, the strong vertical motions associated with these circulations are sufficient to trigger shallow or even deep convection, with associated clouds and precipitation. Furthermore, surface heterogeneity sufficient to force such circulations can arise even without heterogeneity in preexisting land cover characteristics such as vegetation, for example, solely as a result of spatial variability in rainfall and other atmospheric processes. In Part II the mesoscale land–atmosphere interactions in these case study periods are placed in the larger context of the full, monthlong simulations.
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Platov, S. I., V. A. Nekit, and N. N. Ogarkov. "Improving the Controlled Cooling after Wire Rod Rolling in the Finishing Block of Stands." Materials Science Forum 870 (September 2016): 620–24. http://dx.doi.org/10.4028/www.scientific.net/msf.870.620.
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The thermal regime of rolling in the finishing block of stands and the cooling path after rolling largely determines the mechanical properties of the wire rod. One of the main challenges that must be addressed in the cooling design phase is reduction of temperature non-uniformity over the cross section of a wire rod. The use of adjustable cooling allows getting closer in finishing rolling mill to the regimes of the controlled rolling, thermo mechanical processing and two-phase rolling, which greatly extend the capabilities of the mill in the obtaining of high consumer properties of products. The paper presents the theory and experimental analysis of controlled cooling after rolling in the finishing rolling mill, with the aim to rise temperature heterogeneity over the cross section of the wire rod.
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Marotta, Veronica, Yue Wu, Kaifu Zhang, and Alessandro Acquisti. "The Welfare Impact of Targeted Advertising Technologies." Information Systems Research 33, no. 1 (March 2022): 131–51. http://dx.doi.org/10.1287/isre.2021.1024.
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We analyze the welfare implications of consumer data sharing, and restrictions to that sharing, in the context of online targeted advertising. Targeting technologies offer firms the ability to reach desired audiences through intermediary platforms. The platforms run auctions in real time to display ads on internet sites, leveraging consumers’ personal information collected online to personalize the ads. The online advertising industry posits that targeted advertising benefits advertising firms (that is, merchants who want to target ads to the desired consumers), consumers who see ads for preferred products, and the intermediary platforms that match consumers with firms. However, the claims that targeted advertising benefits all players involved have not been fully vetted in the literature. We develop an analytical model to analyze the economic and welfare implications of targeting technologies for those three players under alternative consumer information regimes. The regimes differ in the type and amount of consumer data available to the intermediary and to the advertising firms, and reflect the presence or absence of technological or regulatory restrictions to personal information flows. We find evidence of incentive misalignment among the players, as the intermediary prefers to share only a subset of consumer information with firms, whereas advertising firms prefer having complete information about the consumers. As such, a strategic intermediary with the ability to control which information is shared during the auction can have an incentive to use only the information that maximizes its payoff, overlooking the interests of both advertising firms and consumers. The information regimes that maximize consumer welfare vastly differ depending on consumers’ heterogeneity along two dimensions: a horizontal dimension, capturing consumer’s heterogeneity in product preferences; and a vertical dimension, capturing consumers’ heterogeneity in purchase power. Consumers prefer none of their personal information to be used for targeting only in limited circumstances. Otherwise, consumers are either indifferent or prefer only specific types of information to be used for targeting.
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Vaughan, Gareth L., Luke G. Bennetts, and Vernon A. Squire. "The decay of flexural-gravity waves in long sea ice transects." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 465, no. 2109 (June 24, 2009): 2785–812. http://dx.doi.org/10.1098/rspa.2009.0187.
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Flexural oscillations of floating sea ice sheets induced by ocean waves travelling at the boundary between the ice and the water below can propagate great distances. But, by virtue of scattering, changes of ice thickness and other properties encountered during the journey affect their passage, notwithstanding attenuation arising from several other naturally occurring agencies. We describe here a two-dimensional model that can simulate wave scattering by long (approx. 50 km) stretches of inelastic sea ice, the goal being to replicate heterogeneity accurately while also assimilating supplementary processes that lead to energy loss in sea ice at scales that are amenable to experimental validation. In work concerned with scattering from solitary or juxtaposed stylized features in the sea ice canopy, reflection and transmission coefficients are commonly used to quantify scattering, but on this occasion, we use the attenuation coefficient as we consider that it provides a more helpful description when dealing with long sequences of adjoining scatterers. Results show that scattering and viscosity both induce exponential decay and we observe three distinct regimes: (i) low period, where scattering dominates, (ii) high period, where viscosity dominates, and (iii) a transition regime. Each regime’s period range depends on the sea ice properties including viscosity, which must be included for the correct identification of decay rate.
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Xie, Fagen, Zhilin Qu, Alan Garfinkel, and James N. Weiss. "Electrophysiological heterogeneity and stability of reentry in simulated cardiac tissue." American Journal of Physiology-Heart and Circulatory Physiology 280, no. 2 (February 1, 2001): H535—H545. http://dx.doi.org/10.1152/ajpheart.2001.280.2.h535.
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Generation of wave break is a characteristic feature of cardiac fibrillation. In this study, we investigated how dynamic factors and fixed electrophysiological heterogeneity interact to promote wave break in simulated two-dimensional cardiac tissue, by using the Luo-Rudy (LR1) ventricular action potential model. The degree of dynamic instability of the action potential model was controlled by varying the maximal amplitude of the slow inward Ca2+ current to produce spiral waves in homogeneous tissue that were either nearly stable, meandering, hypermeandering, or in breakup regimes. Fixed electrophysiological heterogeneity was modeled by randomly varying action potential duration over different spatial scales to create dispersion of refractoriness. We found that the degree of dispersion of refractoriness required to induce wave break decreased markedly as dynamic instability of the cardiac model increased. These findings suggest that reducing the dynamic instability of cardiac cells by interventions, such as decreasing the steepness of action potential duration restitution, may still have merit as an antifibrillatory strategy.
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Danilov, S. V., I. A. Mustaeva, and M. A. Golovnin. "Influence of Hot Rolling Technological Regimes on 6061 Aluminium Alloy Sheet Texture." Solid State Phenomena 265 (September 2017): 999–1004. http://dx.doi.org/10.4028/www.scientific.net/ssp.265.999.
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The effect of the hot rolling speed on the textural and structural state of 6061aluminum alloy sheet was investigated. The final deformation temperature allows avoiding the development of recrystallization processes due the decrease of rolling speed. The heterogeneity of the texture state is provided for by the differences in stress conditions for semifinished rolled plate. The deformation texture of the central layer of the hot-rolled sheet corresponds to the stable orientations of the rolling texture of the fcc material. The deformation texture of the surface area generally corresponds to the shear texture of the material with fcc lattice. The recrystallization texture is more scattered, however its component composition is the same as for the deformation texture, but the main orientations can either be maintained of varied.
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Andersen, Lars Pynt, Frank Lindberg, and Jacob Ostberg. "Unpacking Nordic branding: the value regimes of Nordicness." Journal of Place Management and Development 14, no. 3 (February 22, 2021): 362–78. http://dx.doi.org/10.1108/jpmd-12-2019-0113.
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Purpose This paper aims to develop place branding theory toward the accommodation of a multifaceted understanding of value and value negotiation by Nordic branding actors by way of answering the following question: How is Nordicness appropriated by Nordic branding actors and what value regimes are drawn on in the process? Design/methodology/approach Using field data from a selection of branding actors and sectors in Norway, Sweden and Denmark, a qualitative analysis of Nordic branding performances is used to unpack the negotiations of valuation of worth. Findings The analysis identified three principle orders of worth behind Nordicness (civic, green and inspired) that are negotiated through compromises between orders of industry and domestic and by contesting the orders of fame and market. The findings indicate how Nordicness is performed as principle worths and tensions and how these are rendered meaningful as propositions of “value as difference” as they are performed in practice by brand actors. Originality/value Several studies focus on how place branding “adds value;” however, few studies have been aimed at unpacking how a “value universe” is negotiated as a more complex understanding of worth or “value.” This study thus opens up for branding heterogeneity, which signifies awareness of competing notions and orders of worth among small- and medium-sized enterprises and other central stakeholders; this could further inspire interdisciplinary, value-based research into the potential contingencies of (product) branding and place branding in other contexts and regions.
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du Lac, Melchior, Andrew H. Scarpelli, Andrew K. D. Younger, Declan G. Bates, and Joshua N. Leonard. "Predicting the Dynamics and Heterogeneity of Genomic DNA Content within Bacterial Populations across Variable Growth Regimes." ACS Synthetic Biology 6, no. 7 (October 7, 2016): 1131–39. http://dx.doi.org/10.1021/acssynbio.5b00217.
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Ö Stefánsson, M., R. D. FitzGerald, and T. F. Cross. "Growth, feed utilization and growth heterogeneity in juvenile turbot Scophthalmus maximus (Rafinesque) under different photoperiod regimes." Aquaculture Research 33, no. 3 (March 2002): 177–87. http://dx.doi.org/10.1046/j.1365-2109.2002.00651.x.
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