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Dell’Erba, Salvatore, Emanuele Baldacci i Tigran Poghosyan. "Spatial spillovers in emerging market spreads". Empirical Economics 45, nr 2 (26.10.2012): 735–56. http://dx.doi.org/10.1007/s00181-012-0644-7.
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Dell'Erba, Salvatore, Emanuele Baldacci i Tigran Poghosyan. "Spatial Spillovers in Emerging Market Spreads". IMF Working Papers 11, nr 221 (2011): 1. http://dx.doi.org/10.5089/9781463904234.001.
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Suksamran, Jeerawan, Yongwimon Lenbury i Sanoe Koonprasert. "Traveling Wave Solutions of a Four Dimensional Reaction-Diffusion Model for Porcine Reproductive and Respiratory Syndrome with Time Dependent Infection Rate". Computation 9, nr 3 (9.03.2021): 30. http://dx.doi.org/10.3390/computation9030030.
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Porcine reproductive and respiratory syndrome virus (PRRSV) causes reproductive failure in sows and respiratory disease in piglets and growing pigs. The disease rapidly spreads in swine populations, making it a serious problem causing great financial losses to the swine industry. However, past mathematical models used to describe the spread of the disease have not yielded sufficient understanding of its spatial transmission. This work has been designed to investigate a mathematical model for the spread of PRRSV considering both time and spatial dimensions as well as the observed decline in infectiousness as time progresses. Moreover, our model incorporates into the dynamics the assumption that some members of the infected population may recover from the disease and become immune. Analytical solutions are derived by using the modified extended hyperbolic tangent method with the introduction of traveling wave coordinate. We also carry out a stability and phase analysis in order to obtain a clearer understanding of how PRRSV spreads spatially through time.
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Foglia, Matteo, Alessandra Ortolano, Elisa Di Febo i Eliana Angelini. "Bad or good neighbours: a spatial financial contagion study". Studies in Economics and Finance 37, nr 4 (14.09.2020): 753–76. http://dx.doi.org/10.1108/sef-03-2020-0082.
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Purpose The purpose of this paper is to study the evolution of financial contagion between Eurozone banks, observing the credit default swaps (CDSs) market during the period 2009–2017. Design/methodology/approach The authors use a dynamic spatial Durbin model that enables to explore the direct and indirect effects over the short and long run and the transmission channels of the contagion. Findings The results show how contagion emerges through physical and financial market links between banks. This finding implies that a bank can fail because people expect other related financial institutions to fail as well (self-fulfilling crisis). The study provides statistically significant evidence of the presence of credit risk spillovers in CDS markets. The findings show that equity market dynamics of “neighbouring” banks are important factors in risk transmission. Originality/value The research provides a new contribution to the analysis of EZ banking risk contagion, studying CDS spread determinants both under a temporal and spatial dimension. Considering the cross-dependence of credit spreads, the study allowed to verify the non-linearity between the probability of default of a debtor and the observed credit spreads (credit spread puzzle). The authors provide information on the transmission mechanism of contagion and, on the effects among the largest banks. In fact, through the study of short- and long-term impacts, direct and indirect, the paper classify banks of systemic importance according to their effect on the financial system.
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Todorova, Zornitsa. "Network Risk in the European Sovereign CDS Market". Review of Finance and Banking 12, nr 2 (31.12.2020): 137–54. http://dx.doi.org/10.24818/rfb.20.12.02.03.
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This paper applies novel tools from spatial econometrics to measure, quantifyand predict sovereign CDS spreads. Network risk is modelled by making each sovereignísCDS spread a function of the CDS spreads of its ìneighborsî in the Önancial network. Themain Öndings of the paper are: (1) the network model improves forecasting accuracy by 15% to 20%; (2) exogenous Önancial shocks propagate in the network of sovereigns and 40 %to 50% of the total e§ect is due to indirect (network) e§ects. These Öndings suggest analternative explanation to the well-known credit spread puzzle. To rationalize the Öndingsthe paper develops a simple structural network model of sovereign credit risk with Önancialcross-holdings and multiple equilibria.
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Kim, Taehyong, Kang Li, Aidong Zhang, Surajit Sen i Murali Ramanathan. "A Computational Model of Mitigating Disease Spread in Spatial Networks". International Journal of Artificial Life Research 2, nr 2 (kwiecień 2011): 77–94. http://dx.doi.org/10.4018/jalr.2011040104.
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This study examines the problem of disease spreading and containment in spatial networks, where the computational model is capable of detecting disease progression to initiate processes mitigating infection spreads. This paper focuses on disease spread from a central point in a 1 x 1 unit square spatial network, and makes the model respond by trying to selectively decimate the network and thereby contain disease spread. Attention is directed on the kinematics of disease spreading with respect to how damage is controlled by the model. In addition, the authors analyze both the sensitivity of disease progression on various parameter settings and the correlation of parameters of the model. As the result, this study suggests that the radius of containment process is the most critical parameter and its best values with the computational model would be a great help to reduce damages from disease spread of a future pandemic. The study can be applied to controlling other virus spread problems in spatial networks such as disease spread in a geographical network and virus spread in a brain cell network.
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Nguyen, Thi-Quynh. "A Review of Applications of Spatial Statistics in the Study of COVID-19 Pandemic in Vietnam". International Journal of Science and Healthcare Research 8, nr 3 (19.07.2023): 31–36. http://dx.doi.org/10.52403/ijshr.20230306.
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The spread of the 2019 novel coronavirus disease (COVID-19) in Wuhan city, China, caused by the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), spreads rapidly across the world and has negatively affected almost all countries. The Covid-19 pandemic has engulfed the world with a rapid, unexpected, and far-reaching global crisis. In the study of COVID-19 pandemic, spatial statistics have played an important role in many aspects, especially in the study of the clustering of COVID-19 pandemic. This paper summarises 24 scientific papers on applications of spatial statistics including the local Moran’s I and Getis-Ord’s statistics on studies of the COVID-19 pandemic in Vietnam. The findings of this study provide insight into not only how to apply spatial clustring in spatial statistics to analyze the clustering of the COVID-19 pandemic, but also preventing the COVID-19 spread across the world. Keywords: Applications, Spatial statistics, spatial clustering, local Moran’s I and Getis-Ord’s G statistics, the COVID-19 pandemic.
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Cornblath, Eli J., Howard L. Li, Lakshmi Changolkar, Bin Zhang, Hannah J. Brown, Ronald J. Gathagan, Modupe F. Olufemi i in. "Computational modeling of tau pathology spread reveals patterns of regional vulnerability and the impact of a genetic risk factor". Science Advances 7, nr 24 (czerwiec 2021): eabg6677. http://dx.doi.org/10.1126/sciadv.abg6677.
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Neuropathological staging studies have suggested that tau pathology spreads through the brain in Alzheimer’s disease (AD) and other tauopathies, but it is unclear how neuroanatomical connections, spatial proximity, and regional vulnerability contribute. In this study, we seed tau pathology in the brains of nontransgenic mice with AD tau and quantify pathology development over 9 months in 134 brain regions. Network modeling of pathology progression shows that diffusion through the connectome is the best predictor of tau pathology patterns. Further, deviations from pure neuroanatomical spread are used to estimate regional vulnerability to tau pathology and identify related gene expression patterns. Last, we show that pathology spread is altered in mice harboring a mutation in leucine-rich repeat kinase 2. While tau pathology spread is still constrained by anatomical connectivity in these mice, it spreads preferentially in a retrograde direction. This study provides a framework for understanding neuropathological progression in tauopathies.
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Peromaa, T.-L., i P. I. Laurinen. "An Illusory Contour Induces Texture Segmentation". Perception 26, nr 1_suppl (sierpień 1997): 310. http://dx.doi.org/10.1068/v970086.
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It is known that neurons in V1 can signal a contour between two out-of-phase gratings [Grosof et al, 1993 Nature (London)365 550 – 552]. We demonstrate that this type of illusory contour can segregate areas of surfaces without any luminance, contrast, or textural difference between the areas. We have studied the conditions under which the illusory contour induces texture segmentation. The target was a circular contrast-inverted area (diameter 0.22 – 8.3 deg) in the centre of an isotropic narrow-band noise texture (centre spatial frequency 0.4 – 7 cycles deg−1). Generally, segmentation was effortless in low-spatial-frequency textures but gradually disappeared with increasing spatial frequency although the contour remained visible. In a staircase experiment, the highest spatial frequency allowing segmentation was measured for each target size. The task was to tell whether the stimulus contained an object or just a contour. A negative power function relates the target diameter and the highest spatial frequency allowing segmentation. The visibility of the contour was independent of the target size. The illusory contour ‘captures’ the texture inside. However, the process is spatially limited. In a separate experiment, the subject used a cursor to point out how far from the contour the capture spreads. A negative relationship between the spatial spread and the spatial frequency of the texture was found. These findings are consistent with the idea that low-level mechanisms signalling illusory contours are involved in perceptual scene segmentation.
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Moses, Melanie E., Steven Hofmeyr, Judy L. Cannon, Akil Andrews, Rebekah Gridley, Monica Hinga, Kirtus Leyba i in. "Spatially distributed infection increases viral load in a computational model of SARS-CoV-2 lung infection". PLOS Computational Biology 17, nr 12 (23.12.2021): e1009735. http://dx.doi.org/10.1371/journal.pcbi.1009735.
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A key question in SARS-CoV-2 infection is why viral loads and patient outcomes vary dramatically across individuals. Because spatial-temporal dynamics of viral spread and immune response are challenging to study in vivo, we developed Spatial Immune Model of Coronavirus (SIMCoV), a scalable computational model that simulates hundreds of millions of lung cells, including respiratory epithelial cells and T cells. SIMCoV replicates viral growth dynamics observed in patients and shows how spatially dispersed infections can lead to increased viral loads. The model also shows how the timing and strength of the T cell response can affect viral persistence, oscillations, and control. By incorporating spatial interactions, SIMCoV provides a parsimonious explanation for the dramatically different viral load trajectories among patients by varying only the number of initial sites of infection and the magnitude and timing of the T cell immune response. When the branching airway structure of the lung is explicitly represented, we find that virus spreads faster than in a 2D layer of epithelial cells, but much more slowly than in an undifferentiated 3D grid or in a well-mixed differential equation model. These results illustrate how realistic, spatially explicit computational models can improve understanding of within-host dynamics of SARS-CoV-2 infection.
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Endo, Tamio, Kiyoshi Nakakuki, Katsumi Kuno i Koichi Sugiyama. "Spatial Distributions of Damage Introduced into GaP by Collimated MeV-Electron Beams–Lateral Spreads of Damage Compared with Electron Spreads". Japanese Journal of Applied Physics 26, Part 1, No. 4 (20.04.1987): 618–22. http://dx.doi.org/10.1143/jjap.26.618.
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Akanni, Lateef Olawale. "Climatic Variations and Spatial Price Differentials of Perishable Foods in Nigeria". Econometric Research in Finance 5, nr 1 (1.06.2020): 1–15. http://dx.doi.org/10.2478/erfin-2020-0001.
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AbstractIn this study, we attempt to examine the factors that explain the spatial price differentials of selected perishable food crops across Nigerian markets. Based on monthly market prices of onions and tomatoes across different States, we examine the implications of climatic variations, cost of transportation and differences in economic sizes on the price spread of these items. The empirical findings from the dynamic heterogeneous panel regressions show that these factors have significant long-run impacts on the difference in food prices across markets. The results highlight climatic differences and transportation costs are important factors in regional price spreads for agricultural commodities and hence the need for specific policies to reduce the prices variability. Policies geared towards improving agriculture value-chain could o er pathways towards mitigating food loss and waste associated with changing climate and transfer costs, and thereby reduction in prices.
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Tanaka, Hidenori, Howard A. Stone i David R. Nelson. "Spatial gene drives and pushed genetic waves". Proceedings of the National Academy of Sciences 114, nr 32 (25.07.2017): 8452–57. http://dx.doi.org/10.1073/pnas.1705868114.
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Gene drives have the potential to rapidly replace a harmful wild-type allele with a gene drive allele engineered to have desired functionalities. However, an accidental or premature release of a gene drive construct to the natural environment could damage an ecosystem irreversibly. Thus, it is important to understand the spatiotemporal consequences of the super-Mendelian population genetics before potential applications. Here, we use a reaction–diffusion model for sexually reproducing diploid organisms to study how a locally introduced gene drive allele spreads to replace the wild-type allele, although it possesses a selective disadvantages> 0. Using methods developed by Barton and collaborators, we show that socially responsible gene drives require 0.5 <s< 0.697, a rather narrow range. In this “pushed wave” regime, the spatial spreading of gene drives will be initiated only when the initial frequency distribution is above a threshold profile called “critical propagule,” which acts as a safeguard against accidental release. We also study how the spatial spread of the pushed wave can be stopped by making gene drives uniquely vulnerable (“sensitizing drive”) in a way that is harmless for a wild-type allele. Finally, we show that appropriately sensitized drives in two dimensions can be stopped, even by imperfect barriers perforated by a series of gaps.
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Braubach, Oliver. "Spatial transcriptomics with single cell resolution". Journal of Immunology 204, nr 1_Supplement (1.05.2020): 159.32. http://dx.doi.org/10.4049/jimmunol.204.supp.159.32.
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Abstract CO-Detection by indEXing (CODEX®) is ultra-high plex immunohistochemistry that relies on a DNA-based tagging approach, whereby antibodies are labeled with specific oligonucleotide tags (barcodes), and dye-oligonucleotides (reporters) are iteratively hybridized and dehybridized across multiple cycles. CODEX® can detect dozens of antigens simultaneously, in situ and at single cell resolution. Single-cell RNA sequencing, on the other hand, provides information about hundreds to thousands of mRNA transcripts, but without spatial context. The purpose of our study was to enrich spatially resolved CODEX® data with gene expression data obtained from CITE-seq experiments performed on the same tissues. CITE-Seq concurrently measures single-cell antigen and gene expression data, and it is possible to combine these results with CODEX® data by means of Spatially-resolved Transcriptomics via Epitope Anchoring1. We are testing this approach in intact tissues and cell spreads in order to expand the depth our spatial analysis platform. The combination of CODEX® and single cell gene expression data provides an all-in-one solution for deeply multiplexed spatial analyses of protein and gene expression with single cell resolution.
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Shelstad, Dixon, Lloyd Queen, David French i Daniel Fitzpatrick. "Describing the Spread of Oak Wilt Using a Geographic Information System". Arboriculture & Urban Forestry 17, nr 7 (1.07.1991): 192–99. http://dx.doi.org/10.48044/jauf.1991.047.
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The oak wilt fungus (C. fagacearum) spreads both through root grafts to adjacent trees and via insects over longer distances. Effective control of the disease requires a better understanding of the spatial and temporal components of both types of spread. Towards that end, color infrared aerial photography covering a ten-year interval of time was interpreted and then analyzed using a GIS for purposes of describing spread rates and areas affected. The GIS allowed rapid and thorough assessment of both overland and local disease spread. New infection centers were found to occur at greater distances than previously reported, and these new centers accounted in total for the most significant component of increase in total area affected by the fungus.
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Polo, Sara M. T. "How Terrorism Spreads: Emulation and the Diffusion of Ethnic and Ethnoreligious Terrorism". Journal of Conflict Resolution 64, nr 10 (10.06.2020): 1916–42. http://dx.doi.org/10.1177/0022002720930811.
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Previous research on the causes of domestic terrorism has tended to focus on domestic determinants. Although this approach can be helpful to understand many causes of terrorism, it implicitly disregards how the tactical choices made by similar nonstate actors elsewhere influence a group’s decision to resort to terrorist tactics. This study argues that the adoption of terrorism among ethnic and ethnoreligious groups results from a process of conditional emulation. Groups are more likely to emulate the terrorist choice of others with whom they are connected by shared political grievances and spatial networks. The theory is tested on a new and original group-level data set of ethnic and ethnoreligious terrorism (1970 to 2009) using geospatial analysis and spatial econometric models. The results provide strong support for the hypothesized mechanism leading to the diffusion of terrorism and suggest that emulation—more than domestic and contextual factors—substantially influences dissidents’ tactic choice.
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Eder, Armin, i Sebastian Keiler. "CDS Spreads and Contagion Amongst Systemically Important Financial Institutions - A Spatial Econometric Approach". International Journal of Finance & Economics 20, nr 4 (16.08.2015): 291–309. http://dx.doi.org/10.1002/ijfe.1516.
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Gardner, Allison M., Natalie C. Pawlikowski, Sarah A. Hamer, Graham J. Hickling, James R. Miller, Anna M. Schotthoefer, Jean I. Tsao i Brian F. Allan. "Landscape features predict the current and forecast the future geographic spread of Lyme disease". Proceedings of the Royal Society B: Biological Sciences 287, nr 1941 (23.12.2020): 20202278. http://dx.doi.org/10.1098/rspb.2020.2278.
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Lyme disease, the most prevalent vector-borne disease in North America, is increasing in incidence and geographic distribution as the tick vector, Ixodes scapularis , spreads to new regions. We re-construct the spatial-temporal invasion of the tick and human disease in the Midwestern US, a major focus of Lyme disease transmission, from 1967 to 2018, to analyse the influence of spatial factors on the geographic spread. A regression model indicates that three spatial factors—proximity to a previously invaded county, forest cover and adjacency to a river—collectively predict tick occurrence. Validation of the predictive capability of this model correctly predicts counties invaded or uninvaded with 90.6% and 98.5% accuracy, respectively. Reported incidence increases in counties after the first report of the tick; based on this modelled relationship, we identify 31 counties where we suspect I. scapularis already occurs yet remains undetected. Finally, we apply the model to forecast tick establishment by 2021 and predict 42 additional counties where I. scapularis will probably be detected based upon historical drivers of geographic spread. Our findings leverage resources dedicated to tick and human disease reporting and provide the opportunity to take proactive steps (e.g. educational efforts) to prevent and limit transmission in areas of future geographic spread.
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Eggers, J., T. Grava, M. A. Herrada i G. Pitton. "Spatial structure of shock formation". Journal of Fluid Mechanics 820 (5.05.2017): 208–31. http://dx.doi.org/10.1017/jfm.2017.205.
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The formation of a singularity in a compressible gas, as described by the Euler equation, is characterized by the steepening and eventual overturning of a wave. Using self-similar variables in two space dimensions and a power series expansion based on powers of $|t_{0}-t|^{1/2}$, $t_{0}$ being the singularity time, we show that the spatial structure of this process, which starts at a point, is equivalent to the formation of a caustic, i.e. to a cusp catastrophe. The lines along which the profile has infinite slope correspond to the caustic lines, from which we construct the position of the shock. By solving the similarity equation, we obtain a complete local description of wave steepening and of the spreading of the shock from a point. The shock spreads in the transversal direction as $|t_{0}-t|^{1/2}$ and in the direction of propagation as $|t_{0}-t|^{3/2}$, as also found in a one-dimensional model problem.
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Rohman, Hendra. "Spatial Patterns of Pulmonary Tuberculosis Analysing Rainfall Patterns in Visual Formation". International Journal of Public Health Science (IJPHS) 7, nr 1 (1.03.2018): 13. http://dx.doi.org/10.11591/ijphs.v7i1.11376.
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Management sustainability related tuberculosis patient treatment was limited. Tuberculosis analysis was still in the form of data aggregation. This is cross sectional survey using geographical information system, analyzed by descriptive methods, the sample included 162 pulmonary tuberrculosis patient in 2014. The variables were pulmonary tuberrculosis patients and isohyet data. Mycrobacterium tuberculosis will be survive and multiply during rainy season. Rainfall data was an increasing pattern from first quarter to fourth quarter in 2014, however data in 2011, 2012 and 2013, which each quarter was largely experiencing sustained increase and decline. Pulmonary tuberrculosis patients were most prevalent in 2014. It was increase in the rainy season. The most high rainfall intensity (> 2400 mm) in east of Lendah and western of Kokap areas, while the lowest intensity (< 1500 mm) in east of Nanggulan, in the south of Panjatan and Galur areas. It was mostly located in areas with high rainfall intensity (2200 - 2400 mm) which spreads and stretches in Sentolo, Wates, and Panjatan areas. Pulmonary tuberrculosis occurred over the rainy season. Spatial pattern distribution of pulmonary tuberrculosis patients in high rainfall intensity spreads and stretches from east to west areas. Active case monitoring program should be performed by tuberculosis program that concerned in areas of high rainfall intensity.
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Andina, Fathiyyah Nur, Anita Ratnasari Rakhmatulloh i Diah Intan Kusumo Dewi. "Impact of Land Use and Transport Interaction on Transmition of COVID-19 in Jakarta". astonjadro 11, nr 3 (21.09.2022): 545. http://dx.doi.org/10.32832/astonjadro.v11i3.7169.
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Land use and transportation are well known to interact and influence one another. The COVID-19 pandemic is the global health crisis. The world faces difficulties managing disasters while making efforts to slowing the spread of COVID-19. The COVID-19 pandemic spreads quickly through physical contact, making it easy to spread in public places. The purpose of this study to determine the effects of land use and transportation interactions on COVID-19 transmission. The quantitative descriptive analysis and spatial statistical methods in Geographic Information Systems (GIS) have been used in this study. Descriptive analysis to describe data related to land use characteristics in the research area. Spatial Statistical Method in GIS to analyze data from both structured and spatial observations. Cross-checking the land use from Google Street View around the bus stop within a 400 meter radius with the existing land use directly yielded the observations. The findings revealed that the type of land use demonstrated an intensity of activity that had a high potential for spreading COVID-19 because at the bus stop with land use around the trading center, shopping centers, and office buildings that have a high activity intensity, it appears that they have a high positive number of COVID-19
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Brefczynski-Lewis, Julie A., Ritobrato Datta, James W. Lewis i Edgar A. DeYoe. "The Topography of Visuospatial Attention as Revealed by a Novel Visual Field Mapping Technique". Journal of Cognitive Neuroscience 21, nr 7 (lipiec 2009): 1447–60. http://dx.doi.org/10.1162/jocn.2009.21005.
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Previously, we and others have shown that attention can enhance visual processing in a spatially specific manner that is retinotopically mapped in the occipital cortex. However, it is difficult to appreciate the functional significance of the spatial pattern of cortical activation just by examining the brain maps. In this study, we visualize the neural representation of the “spotlight” of attention using a back-projection of attention-related brain activation onto a diagram of the visual field. In the two main experiments, we examine the topography of attentional activation in the occipital and parietal cortices. In retinotopic areas, attentional enhancement is strongest at the locations of the attended target, but also spreads to nearby locations and even weakly to restricted locations in the opposite visual field. The dispersion of attentional effects around an attended site increases with the eccentricity of the target in a manner that roughly corresponds to a constant area of spread within the cortex. When averaged across multiple observers, these patterns appear consistent with a gradient model of spatial attention. However, individual observers exhibit complex variations that are unique but reproducible. Overall, these results suggest that the topography of visual attention for each individual is composed of a common theme plus a personal variation that may reflect their own unique “attentional style.”
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Simpson, C. C., J. J. Sharples i J. P. Evans. "Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere-fire numerical model". Natural Hazards and Earth System Sciences Discussions 2, nr 5 (16.05.2014): 3499–531. http://dx.doi.org/10.5194/nhessd-2-3499-2014.
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Abstract. Fire channelling is a form of dynamic fire behaviour, during which a wildland fire spreads rapidly across a steep lee-facing slope in a direction transverse to the background winds, and is often accompanied by a downwind extension of the active flaming region and extreme pyro-convection. Recent work using the WRF-Fire coupled atmosphere-fire model has demonstrated that fire channelling can be characterised as vorticity-driven lateral fire spread (VDLS). In this study, 16 simulations are conducted using WRF-Fire to examine the sensitivity of resolving VDLS to spatial resolution and atmosphere-fire coupling within the WRF-Fire model framework. The horizontal grid spacing is varied between 25 and 90 m, and the two-way atmosphere-fire coupling is either enabled or disabled. At high spatial resolution, the atmosphere-fire coupling increases the peak uphill and lateral spread rate by a factor of up to 2.7 and 9.5. The enhancement of the uphill and lateral spread rate diminishes at coarser spatial resolution, and VDLS is not modelled for a horizontal grid spacing of 90 m. The laterally spreading fire fronts become the dominant contributors of the extreme pyro-convection. The resolved fire-induced vortices responsible for driving the lateral spread in the coupled simulations have non-zero vorticity along each unit vector direction, and develop due to an interaction between the background winds and vertical return circulations generated at the flank of the fire front as part of the pyro-convective updraft. The results presented in this study demonstrate that both high spatial resolution and two-way atmosphere-fire coupling are required to reproduce VDLS within the current WRF-Fire model framework.
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Alvarez-Zuzek, Lucila G., Casey M. Zipfel i Shweta Bansal. "Spatial clustering in vaccination hesitancy: The role of social influence and social selection". PLOS Computational Biology 18, nr 10 (13.10.2022): e1010437. http://dx.doi.org/10.1371/journal.pcbi.1010437.
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The phenomenon of vaccine hesitancy behavior has gained ground over the last three decades, jeopardizing the maintenance of herd immunity. This behavior tends to cluster spatially, creating pockets of unprotected sub-populations that can be hotspots for outbreak emergence. What remains less understood are the social mechanisms that can give rise to spatial clustering in vaccination behavior, particularly at the landscape scale. We focus on the presence of spatial clustering, and aim to mechanistically understand how different social processes can give rise to this phenomenon. In particular, we propose two hypotheses to explain the presence of spatial clustering: (i) social selection, in which vaccine-hesitant individuals share socio-demographic traits, and clustering of these traits generates spatial clustering in vaccine hesitancy; and (ii) social influence, in which hesitant behavior is contagious and spreads through neighboring societies, leading to hesitant clusters. Adopting a theoretical spatial network approach, we explore the role of these two processes in generating patterns of spatial clustering in vaccination behaviors under a range of spatial structures. We find that both processes are independently capable of generating spatial clustering, and the more spatially structured the social dynamics in a society are, the higher spatial clustering in vaccine-hesitant behavior it realizes. Together, we demonstrate that these processes result in unique spatial configurations of hesitant clusters, and we validate our models of both processes with fine-grain empirical data on vaccine hesitancy, social determinants, and social connectivity in the US. Finally, we propose, and evaluate the effectiveness of two novel intervention strategies to diminish hesitant behavior. Our generative modeling approach informed by unique empirical data provides insights on the role of complex social processes in driving spatial heterogeneity in vaccine hesitancy.
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Simpson, C. C., J. J. Sharples i J. P. Evans. "Resolving vorticity-driven lateral fire spread using the WRF-Fire coupled atmosphere–fire numerical model". Natural Hazards and Earth System Sciences 14, nr 9 (5.09.2014): 2359–71. http://dx.doi.org/10.5194/nhess-14-2359-2014.
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Abstract. Vorticity-driven lateral fire spread (VLS) is a form of dynamic fire behaviour, during which a wildland fire spreads rapidly across a steep leeward slope in a direction approximately transverse to the background winds. VLS is often accompanied by a downwind extension of the active flaming region and intense pyro-convection. In this study, the WRF-Fire (WRF stands for Weather Research and Forecasting) coupled atmosphere–fire model is used to examine the sensitivity of resolving VLS to both the horizontal and vertical grid spacing, and the fire-to-atmosphere coupling from within the model framework. The atmospheric horizontal and vertical grid spacing are varied between 25 and 90 m, and the fire-to-atmosphere coupling is either enabled or disabled. At high spatial resolutions, the inclusion of fire-to-atmosphere coupling increases the upslope and lateral rate of spread by factors of up to 2.7 and 9.5, respectively. This increase in the upslope and lateral rate of spread diminishes at coarser spatial resolutions, and VLS is not modelled for a horizontal and vertical grid spacing of 90 m. The lateral fire spread is driven by fire whirls formed due to an interaction between the background winds and the vertical circulation generated at the flank of the fire front as part of the pyro-convective updraft. The laterally advancing fire fronts become the dominant contributors to the extreme pyro-convection. The results presented in this study demonstrate that both high spatial resolution and two-way atmosphere–fire coupling are required to model VLS with WRF-Fire.
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Helbing, Dirk, Attila Szolnoki, Matjaž Perc i György Szabó. "Punish, but not too hard: how costly punishment spreads in the spatial public goods game". New Journal of Physics 12, nr 8 (3.08.2010): 083005. http://dx.doi.org/10.1088/1367-2630/12/8/083005.
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Ishitani, Tohru, i Kaoru Ohya. "Comparison in spatial spreads of secondary electron information between scanning ion and scanning electron microscopy". Scanning 25, nr 4 (6.12.2006): 201–9. http://dx.doi.org/10.1002/sca.4950250407.
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Peet, Eric R., i Richard Peet. "COVID-19: disease of global capitalism excursions into spatial epidemiology". Human Geography 13, nr 3 (7.10.2020): 318–21. http://dx.doi.org/10.1177/1942778620962028.
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COVID-19 is not deadly in terms of its mortality rate—3.1% in the US. And almost as many people die because of wrong medication or hospital errors. It is deadly in terms of the ease and rapidity with which it spreads—through droplets of spit. And when economies and societies were local and regional in scale, spit did not travel far. But with globalization, especially under finance capitalism, spit travels far, as its carriers move freely—from Wuhan to wherever in a week. COVID-19 is a disease of globalization. It needs to be countered by instantaneous intervention by the WHO and by National Health Services.
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Rekah, Yael, D. Shtienberg i J. Katan. "Spatial Distribution and Temporal Development of Fusarium Crown and Root Rot of Tomato and Pathogen Dissemination in Field Soil". Phytopathology® 89, nr 9 (wrzesień 1999): 831–39. http://dx.doi.org/10.1094/phyto.1999.89.9.831.
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The spatial distribution and temporal development of tomato crown and root rot, caused by Fusarium oxysporum f. sp. radicis-lycopersici, were studied in naturally infested fields in 1996 and 1997. Disease progression fit a logistic model better than a monomolecular one. Geostatistical analyses and semivariogram calculations revealed that the disease spreads from infected plants to a distance of 1.1 to 4.4 m during the growing season. By using a chlorate-resistant nitrate nonutilizing (nit) mutant of F. oxysporum f. sp. radicis-lycopersici as a “tagged” inoculum, the pathogen was found to spread from one plant to the next via infection of the roots. The pathogen spread to up to four plants (2.0 m) on either side of the inoculated focus plant. Root colonization by the nit mutant showed a decreasing gradient from the site of inoculation to both sides of the inoculated plant. Simulation experiments in the greenhouse further established that this soilborne pathogen can spread from root to root during the growing season. These findings suggest a polycyclic nature of F. oxysporum f. sp. radicis-lycopersici, a deviation from the monocyclic nature of many nonzoosporic soilborne pathogens.
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Obuekwe, Ifeyinwa Sarah, Umar Saleh Anka, Sodiq Opeyemi Ibrahim i Usman Ahmad Adam. "Quantifying The Significance of Distance to Temporal Dynamics of Covid-19 Cases in Nigeria Using a Geographic Information System". Geosfera Indonesia 6, nr 1 (25.04.2021): 40. http://dx.doi.org/10.19184/geosi.v6i1.21405.
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The coronavirus disease 2019 (COVID-19) is caused by a new strain of coronavirus that spreads primarily by close contact. Although Nigeria adopted lockdown measures, no defined strategies were used in setting the distance threshold for these lockdowns. Hence, understanding the drivers of COVID-19 is pivotal to an informed decision for containment measures in the absence of vaccines. Spatial and temporal analyses are crucial drivers to apprehending the pattern of diseases over space and time. Thus, this study aimed to quantify the significance of distance to the temporal dynamics of COVID-19 cases in Nigeria using the Geographic Information System. Incremental spatial autocorrelation was used to analyze datasets of each month in ArcGIS. March, April, May, and June exhibited patterns with no significant peaks, while July and August exhibited patterns with two statistically significant peaks. The first and second peaks of July were 301,338.39 and 365,947.83 meters, respectively, while August was 301,338.39 and 336,128.09 meters, respectively. Therefore, a significant difference in the clustering of COVID-19 over distances between July and August was established. This indicated that progression in the spread of the virus increased the virus's spatial coverage while the distance of risk of exposure decreased. This study's findings could be utilized to establish maximum movement restriction areas to contain the spread of COVID-19.
Keywords: Distance; Incremental spatial autocorrelation; Covid-19; Disease; Nigeria
Copyright (c) 2021 Geosfera Indonesia and Department of Geography Education, University of Jember
This work is licensed under a Creative Commons Attribution-Share A like 4.0 International License
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Robin, Cécile, Marie-Laure Desprez-Loustau i Claude Delatour. "Spatial and temporal enlargement of trunk cankers of Phytophthoracinnamomi in red oak". Canadian Journal of Forest Research 22, nr 3 (1.03.1992): 362–66. http://dx.doi.org/10.1139/x92-047.
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Phytophthoracinnamomi Rands is the agent of ink disease on northern red oak (Quercusrubra L.). Cortical cankers on the trunk are the visible symptoms. The fungus causes necrosis of the cambium and phloem, and the tree reacts by forming xylem callus curls. These features can be dated aposteriori on cross sections. The aim of this study was to describe the spatial and temporal development of cankers on cross-sectioned infected oaks. For each lesion, dates of cambium necrosis and formation of callus were recorded at different heights. The following parameters were measured for each lesion: age, height, rate of development, and length and duration of necrosis and canker. Two hundred sixty-three lesions, on 14 trees, were studied. Trees did not exhibit cankers before 9 years of age. All visible trunk cankers could be related to a collar lesion. Phytophthoracinnamomi spreads upwards and can persist for several years, being active seasonally. In this study cambium necrosis occurred preferentially during the first flush. Twenty-nine percent of the lesions were healed over at the collar after 1 year. The collar was less susceptible than the trunk. The other lesions spread rapidly in the cambium of the trunk, which was very vulnerable. They then progressively healed. Therefore, the canker progress curve was bell shaped.
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Ziółkowski, Cezary, i Jan Marcin Kelner. "The Influence Of Propagation Environment On The Accuracy Of Emission Source Bearing". Metrology and Measurement Systems 22, nr 4 (1.12.2015): 591–600. http://dx.doi.org/10.1515/mms-2015-0042.
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Abstract This paper focuses on the radio direction finding (DF) in multipath environments. Based on the measurement results presented in the open literature, the authors analyse the influence of environment transmission properties on the spread of the signal reception angle. Parameters that define these properties are rms delay and angle spreads. For these parameters, the mutual relationship is determined. This relationship is the basis for assessment of the required number of bearings that minimize the influence of the environment on the accuracy of DF procedure. In the presented analysis, the statistical properties of the signal reception angle are approximated by the normal distribution. The number of bearings versus the rms delay spread is presented as the main objective of this paper. In addition, a methodology of the bearings’ spatial averaging that provides better estimation of the reception angle is shown.
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Balassy, Zsombor, Anne-Marie Lauzon i Lennart Hilbert. "Spreading of perturbations in myosin group kinetics along actin filaments". Proceedings of the National Academy of Sciences 116, nr 35 (12.08.2019): 17336–44. http://dx.doi.org/10.1073/pnas.1904164116.
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Global changes in the state of spatially distributed systems can often be traced back to perturbations that arise locally. Whether such local perturbations grow into global changes depends on the system geometry and the spatial spreading of these perturbations. Here, we investigate how different spreading behaviors of local perturbations determine their global impact in 1-dimensional systems of different size. Specifically, we assessed sliding arrest events in in vitro motility assays where myosins propel actin, and simulated the underlying mechanochemistry of myosins that bind along the actin filament. We observed spontaneous sliding arrest events that occurred more frequently for shorter actin filaments. This observation could be explained by spontaneous local arrest of myosin kinetics that stabilizes once it spreads throughout an entire actin filament. When we introduced intermediate concentrations of the actin cross-linker filamin, longer actin was arrested more frequently. This observation was reproduced by simulations where filamin binding induces persistent local arrest of myosin kinetics, which subsequently spreads throughout the actin filament. A spin chain model with nearest-neighbor coupling reproduced key features of our experiments and simulations, thus extending to other linear systems with nearest-neighbor coupling the following conclusions: 1) perturbations that are persistent only once they spread throughout the system are more effective in smaller systems, and 2) perturbations that are persistent upon their establishment are more effective in larger systems. Beyond these general conclusions, our work also provides a theoretical model of collective myosin kinetics with a finite range of mechanical coupling along the actin filament.
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Alov, Ivan N., i Alexander N. Pilyasov. "The spread of the COVID-19 infection in Russia’s Baltic macro-region: internal differences". Baltic Region 15, nr 1 (2023): 96–119. http://dx.doi.org/10.5922/2079-8555-2023-1-6.
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This article explores the spread of the Covid-19 infection in Russia’s Baltic macro-region. The monthly excess mortality rate in the Baltic region is analysed along with regional and municipal Covid-19 response acts to identify regional features affecting the spread of the disease. The spatial characteristics of Russia’s Baltic regions, germane to the propagation of Covid-19, were distinguished by examining selected social and economic statistical indicators. Based on the space of places/space of flows dichotomy, Russia’s Baltic regions can be divided into three spaces: 1) St. Petersburg, the Leningrad and Kaliningrad regions (dominated by spaces of flows; highly permeable space); 2) the Republic of Karelia and the Murmansk region (the key factors are rotational employment and the introduction of the virus from without); 3) the Novgorod and Pskov regions (lowly permeable spaces of places; the central role of local foci of the disease). The principal risk factor for the space of flows is the rapid spread of Covid-19 along transport arteries, whilst, within the space of places, the coronavirus spreads through spatial diffusion from isolated foci along short radii. In the former case, local authorities counteracted spatial diffusion by restricting movement in the local labour market; in the latter, by limiting travel between the centre and the periphery. The traditional ideas about positive (openness, centrality) and negative (closedness, peripherality) characteristics of space are reversed in the context of the pandemic: periphery gains the benefit of natural protection from the pandemic, whilst centres become acutely vulnerable.
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Gu, Xinyue, i Siyan Lin. "Comparing the Spatial Distribution of Popular Destinations in the Era of Mobile Internet: Case Studies of 9 Cities in the Pearl River Delta". Communications in Humanities Research 4, nr 1 (17.05.2023): 578–90. http://dx.doi.org/10.54254/2753-7064/4/20220881.
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In the era of mobile Internet, the development of the influencer economy has given rise to emerging consumer spaces and popular destinations, which are new hot topics for urban public space research. Based on TikTok popular destinations check-in data and using statistical analysis, kernel density analysis, and optimized hotspot method, this study quantitatively measures different spatial distributions of popular destinations in the Pearl River Delta and nine cities within it and explores the relationship between spatial structure and built environment and the causes. The results show that the spatial distribution of popular destinations shows an obvious dual structure, and the spatial hotness spreads and decreases from the central cities (Guangzhou and Shenzhen) to the peripheral cities. Meanwhile, the spatial distribution characteristics of popular destinations within different cities have obvious heterogeneity, and the heterogeneity of developed cities is weaker than that of less developed cities.
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Wu, Tao, Xiaofeng Zhang, Yiwen Li, Zhenghong Deng i Yijie Huang. "On Spatial Smoothing for DOA Estimation of 2D Coherently Distributed Sources with Double Parallel Linear Arrays". Electronics 8, nr 3 (23.03.2019): 354. http://dx.doi.org/10.3390/electronics8030354.
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Considering coherently-distributed (CD) sources are correlated with each other, a two-dimensional (2D) coherent CD source model is proposed according to the characteristics of an underwater acoustic channel. Under the assumption of small angular spreads, rotational invariance relationships within and between subarrays of double parallel linear arrays are derived. As the covariance matrix of spatial smoothing obtained from receive vectors expressed by rotational invariance relationships is proven to be full rank, decoherence of the 2D coherent CD source is proposed by spatial smoothing of the double parallel linear arrays. A propagator method base on spatial smoothing (SS-PM) and estimation of signal parameters via rotational invariance techniques (ESPRIT) base on spatial smoothing (SS-ESPRIT) method established by covariance matrix of spatial smoothing are proposed. The proposed methods do not require peak-searching, angles matching and information of deterministic angular signal distribution function. Simulations are conducted to verify the effectiveness of the proposed methods.
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Kempiak, Stephan J., Shu-Chin Yip, Jonathan M. Backer i Jeffrey E. Segall. "Local signaling by the EGF receptor". Journal of Cell Biology 162, nr 5 (1.09.2003): 781–88. http://dx.doi.org/10.1083/jcb.200303144.
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Differing spatial scales of signaling cascades are critical for cell orientation during chemotactic responses. We used biotin EGF bound to streptavidin-coupled magnetic beads to locally stimulate cells overexpressing the EGF receptor. We have found that EGF-induced actin polymerization remains localized even under conditions of receptor overexpression. Conversely, EGF-induced ERK activation spreads throughout the cell body after EGF bead stimulation. The localized actin polymerization is independent of PI3-kinase and rho protein activity and requires Arp2/3 complex and cofilin function. Thus, we find differing spatial scales of signaling from the EGF receptor, supporting models of chemotaxis that integrate short- and long-range signaling.
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Souza, Misael Possidonio de, i Milton José Porsani. "Filtering of cross spreads using multichannel singular spectrum analysis and instantaneous frequency methods". Brazilian Journal of Geophysics 39, nr 4 (2.12.2021): 645. http://dx.doi.org/10.22564/rbgf.v39i4.2118.
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ABSTRACT. The orthogonal geometry of 3D seismic data acquisition generates cross-spreads, which are small subsets of multidimensional data. These subsets present unique properties, where ground roll and linear noises become geometrically easy to detect, and multidimensional filters play an essential role in seismic processing. In the present paper, we show the application of combined time-domain Recursive and Iterative Multichannel Singular Spectrum Analysis and average instantaneous frequency methods for random and coherent noise attenuation and enhancement of the reflections in the cross spread. The methodology starts decomposing the cross spread into a set of components, by the recursive-iterative Singular Spectrum Analysis method. The average instantaneous frequency method identifies the low-frequency areas associated with the ground roll to attenuate by muting and stacking each 3D component, where the instantaneous frequency values match the ground roll bandwidth; then the 3D volume filtering is performed by Multichannel Singular Spectrum Analysis, after NMO correction, enhancing the reflections and increasing the lateral coherence in filtered pre-stack seismic data. Numerical experiments using an example of a cross-spread from 3D land seismic data have shown excellent results of the extension of our methodology for random noise and ground roll attenuation in the cross-spread domain.Keywords: time-series analysis; seismic noise; image processing; Fourier analysis; spatial analysis; cross-spreads; interface waves. Filtragem sísmica de cross-spreads através da aplicação dos métodos análise espectral singular multicanal e frequência instantâneaRESUMO. A geometria ortogonal da aquisição de dados sísmicos 3D gera cross-spreads ou lancos cruzados, que são pequenos subconjuntos de dados multidimensional, os quais apresentam propriedades únicas, nos quais ruídos lineares e ground roll tornam-se geometricamente fáceis de serem detectados por filtros multidimensionais. Neste artigo apresentamos uma abordagem de filtragem no domínio do tempo que combina as aplicações do método Análise Espectral Singular e do método de obtenção da frequência média instantânea, que possibilita a atenuação do ground roll e o aumento da coerência lateral das reflexões. A metodologia se inicia com a decomposição dos dados em componentes, através do método Análise Espectral Singular recursiva e iterativa. Essa etapa e seguida da aplicação do método de frequência média instantânea, que permite identificar as áreas de baixa frequência associadas ao ground roll. Assim, efetuamos o silenciamento das amplitudes das componentes, nas áreas em que a frequência média instantânea corresponde a frequência do ground roll. Ao final, fazemos a correção de NMO e aplicamos o método Análise Espectral Singular Recursivo e Iterativo multicanal, que favorece o aumento da coerência lateral das reflexões no dado pré-empilhado. Experimentos numéricos usando um cross-spread de dados sísmicos 3D terrestres mostraram excelentes resultados.Palavras-chave: geofísica aplicada; processamento digital de sinais; processamento de dados sísmicos; métodos sísmicos.
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Thi-Quynh Nguyen, Thi-Thuy Ngo i Thi-Binh Than. "Spatial clustering analysis of COVID-19 using LISA: A case study of the 2022 winter Day in Hanoi, Vietnam". World Journal of Biology Pharmacy and Health Sciences 15, nr 2 (30.08.2023): 187–94. http://dx.doi.org/10.30574/wjbphs.2023.15.2.0361.
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Background:A novel coronavirus disease outbreak in 2019 (COVID-19) caused by he emergence of severe acute respiratory syndrome coronavirus 2 (SARS CoV 2) in China quickly spreads throughout the world. This study aimed to analyze the spatial clustering of COVID-19. Methods:The global and local Moran's I statistic (LISA) was used to investigate the spatial clusters of COVID-19 including spatial clusters (high-high and low-low) and spatial outliers (low-high and high-low). Results: A case study of COVID-19 locally transmitted cases reported in a 2022 winter day in Hanoi city has indicated that high-high spatial clusters were totally concentrated in 6 urban districts in the Hanoi metropolitan including such as districts of Dong Da, Gia Lam, Thanh Tri, Hai Ba Trung, Cau Giay, and Long Bien. Whereas, low-low spatial clusters were mainly in sub-urban districts such as Ba Vi, Thach That, Phuc Tho, and Son Tay town (0 cases) in the northwest and Ung Hoa district in the south of Hanoi. Conclusions:The study results indicated the effectiveness of LISA in analysis of spatial clustering of COVID-19. Findings in this study make great contributions to the fight of the COVID-19 pandemic.
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Vermeer, Gijs J. O. "Factors affecting spatial resolution". GEOPHYSICS 64, nr 3 (maj 1999): 942–53. http://dx.doi.org/10.1190/1.1444602.
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The theory of spatial resolution has been well‐established in various papers dealing with inversion and prestack migration. Nevertheless, there is a continuing flow of papers being published on spatial resolution, in particular in relation to spatial sampling. This paper continues the discussion, and deals with various factors affecting spatial resolution. The theoretical best‐possible resolution can be predicted using Beylkin’s formula. This formula gives answers on the effect on resolution of frequency, aperture, offset, and acquisition geometry. In this paper, these factors are investigated using a single diffractor in a constant‐velocity medium. Some simple resolution formulas are derived for 2-D zero‐offset data. These formulas are similar to formulas derived elsewhere in a more heuristic way, and which are in common use in the industry. The formulas are extended to 2-D common‐offset data. The width of the spatial wavelet resulting from migration of the diffraction event is compared with the resolution predicted from Beylkin’s formula for various 3-D single‐fold data sets. The measured widths confirm the theoretical prediction that zero‐offset data produce the best possible resolution and 3-D shots the worst, with common‐offset gathers and cross‐spreads scoring intermediate. The effects of sampling and fold cannot be derived directly from Beylkin’s formula; these effects are analyzed by looking at the migration noise rather than at the width of the spatial wavelet. Random coarse sampling may produce somewhat less migration noise than regular coarse sampling, though it cannot be as good as regular dense sampling. The bin‐fractionation technique (which achieves finer midpoint sampling without changing the station spacings) does not achieve higher resolution than conventional sampling. Generally speaking, increasing fold does not improve the theoretically best possible resolution. However, as noise always has a detrimental effect on the resolvability of events, fold—by reducing noise—will improve resolution in practice. This also applies to migration noise as a product of coarse sampling.
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Lima, Fernando T., Nathan C. Brown i José P. Duarte. "Understanding the Impact of Walkability, Population Density, and Population Size on COVID-19 Spread: A Pilot Study of the Early Contagion in the United States". Entropy 23, nr 11 (14.11.2021): 1512. http://dx.doi.org/10.3390/e23111512.
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The novel coronavirus disease 2019 (COVID-19) pandemic is an unprecedented global event that has been challenging governments, health systems, and communities worldwide. Available data from the first months indicated varying patterns of the spread of COVID-19 within American cities, when the spread was faster in high-density and walkable cities such as New York than in low-density and car-oriented cities such as Los Angeles. Subsequent containment efforts, underlying population characteristics, variants, and other factors likely affected the spread significantly. However, this work investigates the hypothesis that urban configuration and associated spatial use patterns directly impact how the disease spreads and infects a population. It follows work that has shown how the spatial configuration of urban spaces impacts the social behavior of people moving through those spaces. It addresses the first 60 days of contagion (before containment measures were widely adopted and had time to affect spread) in 93 urban counties in the United States, considering population size, population density, walkability, here evaluated through walkscore, an indicator that measures the density of amenities, and, therefore, opportunities for population mixing, and the number of confirmed cases and deaths. Our findings indicate correlations between walkability, population density, and COVID-19 spreading patterns but no clear correlation between population size and the number of cases or deaths per 100 k habitants. Although virus spread beyond these initial cases may provide additional data for analysis, this study is an initial step in understanding the relationship between COVID-19 and urban configuration.
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Kumar, Chetti Praveen. "Sustainable Agriculture in India - Natural Farming Spreads Roots in Andhra Pradesh". Shanlax International Journal of Arts, Science and Humanities 10, nr 2 (1.10.2022): 16–21. http://dx.doi.org/10.34293/sijash.v10i2.5159.
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Indian agriculture sector is the most vulnerable due to climate change challenges like uncertain rainfall and water stress and coupled with week economic status of the farmers. The Indian agriculture sector facing three different challenges, such that high cost of production, low production and productivity and degradation of natural resources with affected agroecological system. Now it evident that serious concerns raised about the future problems related to country with the present approach. Natural farming can produce nutritious food without harming the environment or the health of the soil. The Andhra Pradesh state was specifically chosen for the study since it has more than 750000 farmers that practice natural farming there. The secondary data have been used which is drown from the RySS and Indiastat and also related reposts, and the study referred various previous studies and research articles from the existing literature. The study investigates the spatial distribution analysis by using ArcGIS. And the study analyzed the yield and net returns of the natural and non-natural farming in the study area. Natural farmers will gain more from lower cultivation costs, higher crop yields, higher earnings, better, healthier, more nutrient-rich food, environmental preservation, and reduced soil erosion. In addition, ecological farming requires less capital, which lowers debt loads.
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Fu, Chunyu, Peiji Shi, Tao Feng i Weiping Zhang. "Spatio-temporal difference analysis of land use efficiency in Lanxi Urban Agglomeration based on SBM-Undesirable model". E3S Web of Conferences 194 (2020): 05062. http://dx.doi.org/10.1051/e3sconf/202019405062.
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Based on the connotation of green development, SBM-Undesirable model was used to measure the land use efficiency of Lanxi Urban Agglomeration in 2006, 2010, 2014 and 2018, and Theil Index and Spatial Autocorrelation Methods were used to reveal the spatial difference characteristics. The results show that: (1) From 2006 to 2018, the county land use efficiency of Lanxi Urban Agglomeration increased steadily, and the regional differences first expanded and then narrowed. (2) The land use efficiency of counties in Lanxi Urban Agglomeration presents a spatial difference law of “high in the middle-low in the periphery, high in the west and low in the east, and differentiated between the north and the south”, while the two provinces present a decreasing law of “west-east”. (3) The spatial agglomeration characteristics of land use efficiency in Lanxi Urban Agglomeration are remarkable. Locally, the high-high agglomeration is typical in the central region, while the low-low agglomeration spreads from southeast to southwest.
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Pinem, Mbina. "Analisis Pertumbuhan Dan Persebaran Penduduk Provinsi Sumatera Utara Berdasarkan Hasil Sensus Penduduk Tahun 2010". JUPIIS: JURNAL PENDIDIKAN ILMU-ILMU SOSIAL 6, nr 1 (30.06.2014): 1. http://dx.doi.org/10.24114/jupiis.v6i1.1469.
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This research porposes to understand growth and spread of population in Province of North Sumatra. The method used here is decriptive analysis of secondary data with the spatial approach. Whereas the object of research are the number of population, the population growth, and spread of population of North Sumatra Province based on 2010 census of Indonesian pupulation. The outcome of research represents that the population growth of Province of North Sumatra from 2000 to 2010 average of 1,22 percent per year. Then, the highest population growth found in Regency of Middle Tapanuli (2,46 percent), followed by Regency of Karo (2,17 percent), and South Tapanuli Regency (2,12 percent). Meanwhile the lowest population growth found in Siantar Town (-029 percent) and followed by Toba Samosir Regency (0,38 percent) and Simalungun Regency (-0,46 percent). As the spread of pupulation in the North Sumatra Province is not prevalent, as the settlements spreads nearly 62,87 percent on the east coast region, whereas only 3,05 percent on the west coast, and the rest 4,85 percent on the Nias Islands.
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Sukarna, S., Wahidah Sanusi i Hafilah Hardiono. "Analisis Moran’s I, Geary’s C, dan Getis-Ord G pada Penerapan Jumlah Penderita Kusta di Kabupaten Gowa". Journal of Mathematics, Computations, and Statistics 2, nr 2 (12.05.2020): 151. http://dx.doi.org/10.35580/jmathcos.v2i2.12577.
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Analisis spasial merupakan salah satu metode yang sering digunakan dalam melihat pola penyebaran penyakit menular. Penyakit Kusta atau lepra merupakan penyakit menular kronis yang disebabkan oleh bakteri Mycrobacterium Leprae yang penyebarannya melalui droplet. Penelitian ini bertujuan untuk mengetahui pola spasial pada Kusta dengan menggunakan metode Quadrat Analysis, untuk mengetahui ada atau tidaknya autokorelasi spasial antar daerah dengan menggunakan Moran’s I, Geary’s C, Getis-Ord G, dan pemetaan penyebaran penyakit Kusta di Kabupaten Gowa. Pada penelitian ini diperoleh bahwa pola spasial penyebaran penyakit Kusta pada Tahun 2016 dan 2017 di Kabupaten Gowa bersifat mengelompok (clustered). Pada Tahun 2016 terdapat autokorelasi spasial dengan pengujian Moran’s I dan Geary’s C, sedangkan pengujian Getis-Ord G tidak terdapat autokorelasi spasial antar daerah. Pada Tahun 2017 tidak terdapat autokorelasi spasial antar daerah dengan menggunakan ke tiga pengujian tersebut. Pada Tahun 2016 daerah yang rawan adalah Barombong, daerah yang harus berhati-hati dengan daerah sekitarnya adalah Bontonompo dan daerah yang termasuk kategori aman adalah Tompobulu. Sedangkan pada tahun 2017 daerah yang rawan terhadap penyakit Kusta adalah Bajeng dan Manuju.Kata kunci : Moran’s I, Geary’s C, Getis-Ord G, Moran Scatterplot, Kusta Spatial analysis is one of the methods that is often used to observe spreading pattern of infectious diseases. Leprosy is a chronic infectious disease caused by bacterium Mycrobacterium Leprae which spreads through droplets. This study aims to determine the spatial pattern of leprosy using the Quadrat Analysis method, to determine whether there is spatial autocorrelation between regions using Moran's I, Geary’s C, Getis-Ord G, and mapping the spread of leprosy in Gowa Regency. In this study it was found that the spatial patterns of the spread of leprosy in 2016 and 2017 in Gowa Regency was clustered. In 2016 there were spatial autocorrelations with the tests of Moran's I and Geary's C, while the testing of Getis-Ord G did not have spatial autocorrelation between regions. In 2017 there is no spatial autocorrelation between regions using the three tests. In 2016 the vulnerable areas was Barombong, the area that had to be careful with the surrounding areas was Bontonompo and the area included in the safe category was Tompobulu. Whereas in 2017 areas prone to leprosy were Bajeng and Manuju.Keywords : Moran's I, Geary's C, Getis-Ord G, Moran Scatterplot, Leprosy
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Kasai, Tetsuko. "Attention-spreading Based on Hierarchical Spatial Representations for Connected Objects". Journal of Cognitive Neuroscience 22, nr 1 (styczeń 2010): 12–22. http://dx.doi.org/10.1162/jocn.2008.21158.
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Attention selects objects or groups as the most fundamental unit, and this may be achieved through a process in which attention automatically spreads throughout their entire region. Previously, we found that a lateralized potential relative to an attended hemifield at occipito-temporal electrode sites reflects attention-spreading in response to connected bilateral stimuli [Kasai, T., & Kondo, M. Electrophysiological correlates of attention-spreading in visual grouping. NeuroReport, 18, 93–98, 2007]. The present study examined the nature of object representations by manipulating the extent of grouping through connectedness, while controlling the symmetrical structure of bilateral stimuli. The electrophysiological results of two experiments consistently indicated that attention was guided twice in association with perceptual grouping in the early phase (N1, 150–200 msec poststimulus) and with the unity of an object in the later phase (N2pc, 310/330–390 msec). This suggests that there are two processes in object-based spatial selection, and these are discussed with regard to their cognitive mechanisms and object representations.
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Li, Roger W., Truyet T. Tran, Ashley P. Craven, Tsz-Wing Leung, Sandy W. Chat i Dennis M. Levi. "Sharpening coarse-to-fine stereo vision by perceptual learning: asymmetric transfer across the spatial frequency spectrum". Royal Society Open Science 3, nr 1 (styczeń 2016): 150523. http://dx.doi.org/10.1098/rsos.150523.
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Neurons in the early visual cortex are finely tuned to different low-level visual features, forming a multi-channel system analysing the visual image formed on the retina in a parallel manner. However, little is known about the potential ‘cross-talk’ among these channels. Here, we systematically investigated whether stereoacuity, over a large range of target spatial frequencies, can be enhanced by perceptual learning. Using narrow-band visual stimuli, we found that practice with coarse (low spatial frequency) targets substantially improves performance, and that the improvement spreads from coarse to fine (high spatial frequency) three-dimensional perception, generalizing broadly across untrained spatial frequencies and orientations. Notably, we observed an asymmetric transfer of learning across the spatial frequency spectrum. The bandwidth of transfer was broader when training was at a high spatial frequency than at a low spatial frequency. Stereoacuity training is most beneficial when trained with fine targets. This broad transfer of stereoacuity learning contrasts with the highly specific learning reported for other basic visual functions. We also revealed strategies to boost learning outcomes ‘beyond-the-plateau’. Our investigations contribute to understanding the functional properties of the network subserving stereovision. The ability to generalize may provide a key principle for restoring impaired binocular vision in clinical situations.
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LI, XIAODONG, i WILLIAM MAGILL. "CRITICAL DENSITY IN A FIRE SPREAD MODEL UNDER ENVIRONMENTAL INFLUENCE". International Journal of Computational Intelligence and Applications 03, nr 02 (czerwiec 2003): 145–55. http://dx.doi.org/10.1142/s1469026803000896.
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Small changes in spatial pattern on a landscape can sometimes produce dramatic ecological responses. Such transition ranges are associated with critical environmental conditions such as tree density. As the landscape becomes dissected into smaller patches of trees, landscape connectivity may suddenly become disrupted, which may have important consequences for the behaviours of forest fire, i.e. how it spreads. Landscape connectivity depends not only on the tree density but also many other environmental conditions such as land height, flammability, and wind conditions. To determine how the critical densities are affected by the changes in these conditions, we developed a fire spread simulation model using a multi-agent (i.e. bottom-up) approach. This model simulates an artificial environment where bush is randomly generated and fire can be ignited and then spread across the environment according to some "interaction rules". The emergent fire spread behaviours at the landscape level are determined by such micro-level "interaction rules". This model takes into account some major environmental factors that influence fire growth. By varying these variables under controlled conditions, this research aims to show how varied environmental conditions affect the critical density, and hence influence the spread and growth of fire.
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LEVI, REGEV, EYTAN RUPPIN, YOSSI MATIAS i JAMES A. REGGIA. "FREQUENCY-SPATIAL TRANSFORMATION: A PROPOSAL FOR PARSIMONIOUS INTRA-CORTICAL COMMUNICATION". International Journal of Neural Systems 07, nr 05 (listopad 1996): 591–98. http://dx.doi.org/10.1142/s0129065796000579.
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This work examines a neural network model of a cortical module, where neurons are organized on a 2-dimensional sheet and are connected with higher probability to their spatial neighbors. Motivated by recent findings that cortical neurons have a resonant peak in their impedance magnitude function, we present a frequency-spatial transformation scheme that is schematically described as follows: An external input signal, applied to a small input subset of the neurons, spreads along the network. Due to a stochastic component in the dynamics of the neurons, the frequency of the spreading signal decreases as it propagates through the network. Depending on the input signal frequency, different neural assemblies will hence fire at their specific resonance frequency. We show analytically that the resulting frequency-spatial transformation is well-formed; an injective, fixed, mapping is obtained. Extensive numerical simulations demonstrate that a homogeneous, well-formed transformation may also be obtained in neural networks with cortical-like “Mexican-hat” connectivity. We hypothesize that a frequency-spatial transformation may serve as a basis for parsimonious cortical communication.
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Fung, Christine W., Jia Guo, Hongjun Fu, Helen Y. Figueroa, Elisa E. Konofagou i Karen E. Duff. "Atrophy associated with tau pathology precedes overt cell death in a mouse model of progressive tauopathy". Science Advances 6, nr 42 (październik 2020): eabc8098. http://dx.doi.org/10.1126/sciadv.abc8098.
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Tau pathology in Alzheimer’s disease (AD) first develops in the entorhinal cortex (EC), then spreads to the hippocampus, followed by the neocortex. Overall, tau pathology correlates well with neurodegeneration and cell loss, but the spatial and temporal association between tau pathology and overt volume loss (atrophy) associated with structural changes or cell loss is unclear. Using in vivo magnetic resonance imaging (MRI) with tensor-based morphometry (TBM), we mapped the spatiotemporal pattern of structural changes in a mouse model of AD-like progressive tauopathy. A novel, coregistered in vivo MRI atlas was then applied to identify regions in the medial temporal lobe that had a significant volume reduction. Our study shows that in a mouse model of tauopathy spread, the propagation of tau pathology from the EC to the hippocampus is associated with TBM-related atrophy, but atrophy in the dentate gyrus and subiculum precedes overt cell loss.