Spatial Distribution Of Activity Research Articles

Urban magnetism through the lens of geo-tagged photography

There is an increasing trend of people leaving digital traces through social media. This reality opens new horizons for urban studies. With this kind of data, researchers and urban planners can detect many aspects of how people live in cities and can also suggest how to transform cities into more efficient and smarter places to live in. In particular, their digital trails can be used to investigate tastes of individuals, and what attracts them to live in a particular city or to spend their vacation there. In this paper we propose an unconventional way to study how people experience the city, using information from geotagged photographs that people take at different locations. We compare the spatial behavior of residents and tourists in 10 most photographed cities all around the world. The study was conducted on both a global and local level. On the global scale we analyze the 10 most photographed cities and measure how attractive each city is for people visiting it from other cities within the same country or from abroad. For the purpose of our analysis we construct the users’ mobility network and measure the strength of the links between each pair of cities as a level of attraction of people living in one city (i.e., origin) to the other city (i.e., destination). On the local level we study the spatial distribution of user activity and identify the photographed hotspots inside each city. The proposed methodology and the results of our study are a low cost mean to characterize touristic activity within a certain location and can help cities strengthening their touristic potential.

On the spatial economic impact of global warming

We propose a dynamic spatial theory to analyze the geographic impact of climate change. Agricultural and manufacturing firms locate on a hemisphere. Trade is costly, firms innovate, and technology diffuses over space. Emissions from energy used in production contribute to the atmospheric stock of carbon, which increases temperature. Warming differs across latitudes and its effect on productivity varies across sectors. We calibrate the model to analyze how climate change affects the spatial distribution of economic activity, trade, migration, growth, and welfare. We assess quantitatively the impact of migration and trade restrictions, energy taxes, and innovation subsidies.

Experimental muscle pain induces a shift of the spatial distribution of upper trapezius muscle activity during a repetitive task

Background. Myalgia frequently affects the upper trapezius muscle, and patients typically complain of dull pain and stiffness. Evidence suggests a correlation between repetitive movements, awkward posture, and the development of neck-shoulder muscle pain. However the mechanisms underlying these associations remain unclear. Purpose. To investigate the effect of experimentally induced upper trapezius muscle pain on the distribution of upper trapezius muscle activity during a repetitive task. It was hypothesized that pain would change the distribution of muscle activity resulting in activation of upper trapezius muscle regions which would not normally be active during the task. Methods. Ten healthy male (age: 26.2 ± 3.1 years) volunteers participated. Subjects lifted a 1 kg box between shelves positioned at hip and shoulder height with a cycle time of 3 s for 50 cycles. The task was repeated: 1. baseline, 2. following injection of 0.4 ml isotonic saline (0.9%) into the right upper trapezius muscle, 3. following injection of 0.4 ml hypertonic saline (5.8%) into the right upper trapezius muscle and 4. 15 mins after the last injection. Pain intensity ratings were obtained immediately following the injection and every 30 s until pain was no longer reported. Surface electromyography (EMG) was recorded from the upper trapezius muscle using a grid of 64 electrodes and 4 uniaxial accelerometers were mounted on the box to obtain the start and end points of the cyclic movement. The EMG root mean square (RMS) was computed for each location of the electrode grid to form a map of the EMG amplitude distribution.The following EMG variables were extracted from the RMS maps: mean RMS, entropy, and y- (cranial-caudal) and x-axis (medio-lateral) coordinates of the centroid of the RMS map. The EMG variables were then averaged across the 50 cycles for each epoch of the cycle. Results. Peak pain intensity was greater following the injection of hypertonic (4.7 ± 1.9/10) compared to isotonic saline (0.8 ± 1.1, P 0.05). Conclusions. The results indicate that nociceptive stimulation of the upper trapezius during a repetitive task changes the distribution of upper trapezius muscle activity and its amplitude. Implications. The described alterations of muscle activity may have an important role in the perpetuation of pain during repetitive activity.

Ticks and tick-borne pathogens in South Bohemia (Czech Republic) – Spatial variability in Ixodes ricinus abundance, Borrelia burgdorferi and tick-borne encephalitis virus prevalence

Spatial distribution of Ixodes ricinus tick host-seeking activity, as well as prevalence of Borrelia burgdorferi sensu lato and tick-borne encephalitis virus (TBEV) were studied in the TBE endemic area of South Bohemia (Czech Republic). High variability in tick abundance detected in a network of 30 study sites was most closely associated with characteristics of vegetation cover. Of 11,182 tested tick samples, 12% carried DNA of spirochete from B. burgdorferi s.l. complex. B. afzelii and B. garinii prevailed among spirochete species. The presence of B. spielmanii in the region was confirmed. The median number of borrelial genome copies in positive samples reached 6.6×103 by real-time PCR. The total prevalence of TBEV in pooled samples reached 0.32% (20,057 samples tested), at least one TBEV positive tick was present in 21 out of 30 sampling sites.

Offshore Service Vessel activity forecast and regulatory modeling in the U.S. Gulf of Mexico, 2012–2017

Offshore support vessels (OSVs) have important economic and environmental impacts on coastal communities in the Gulf Coast region and these impacts depend on the quantity and spatial distribution of vessel activity, which in turn depends on the type and geographic distribution of exploration and development. In this paper, port activity is quantified according to offshore activity expected to arise from current and new lease sales categorized according to water depth, planning area, and vessel class. Between 53,000 and 119,000 trips per year are expected to be required to support exploration, development and production in the Gulf of Mexico from 2012 to 2017, and approximately half of all trips are expected to emanate from Port Fourchon, Louisiana, with the next largest port, Cameron, Louisiana, contributing an additional 14% of activity. During the 2012–2017 period, the majority of trips are expected to support shallow water production operations.

Spatial Distribution of HTO Activity in Unsaturated Soil Depth in the Vicinity of Long-term Release Source

Charles Murphy reported about correlation between HTO activity distribution in unsaturated soil layer and atmospheric long-term releases of HTO in the vicinity of Savannah River Site. Tritium Working Group of BIOMASS Programme performed a model-model intercomparison study of HTO transport from atmosphere to unsaturated soil and evaluated HTO activity distribution in the unsaturated soil layer in the vicinity of permanent atmospheric sources. Tritium Working Group has also reported about such a correlation, however the conclusion was that experimental data sets are needed to confirm this conclusion and also to validate appropriate computer models.

A downscaling technique to simulate changes in western North Pacific tropical cyclone activity between two types of El Niño events

Changes in tropical cyclone (TC) activity over the western North Pacific (WNP) basin between the Modoki and canonical El Nino years have been simulated and examined in this study based on a downscaling technique. The downscaling technique is used for generating synthetic TCs based on TC formation, TC track, and TC intensity models. Results suggest that the downscaling technique can well simulate the spatial distribution of TC activity during the two types of El Nino years and their differences. It is found that the observed changes in TC tracks during the two types of El Nino years are mainly due to the combined effects of changes in TC formation locations and large-scale steering flows. Further examinations have shown that changes in large-scale steering flows play a more important role than changes in TC formation locations. These results are in accordance with the cyclonic circulation anomaly found during the Modoki El Nino years compared to that during the canonical El Nino years. Numerical simulations further suggest that changes in TC tracks between the two types of El Nino years appear to be the most important factor affecting the TC intensity change. Compared to that during the Modoki El Nino years, TC formation is enhanced in the south quadrant of the WNP basin and more TCs take a northwestward track during the canonical El Nino years, leading to a longer TC lifespan and greater TC intensity.

Globalization, Economic Restructuring and Competitiveness in the Metropolitan Area of Leon, Guanajuato, Mexico

Social and territorial spaces around the world are undergoing economic restructuring due to globalization process that has led to the removal of restrictions on capital mobility and the factors of production, and therefore, flows of capital, goods, technology, and especially the expansion of markets. This transnational reorganization of production and market globalization have led to the relocation of economic activity and spatial agglomerations. The relocation of production activities has generated local spaces acquire great importance, precisely because of the mobility and networking in the space of the different capitals: production, financial, human, and goods and information. Certainly globalization changes the spatial distribution of economic activity and accentuates socioeconomic differences among localities and regions, since they exhibit different rates of economic growth and social progress, because these spaces are not inserted in the same way, not to the same degree, in the new globalized economy. In this paper, the economic restructuring that has experienced the metropolitan area is analyzed in Metropolitan Area of LeA³n (MAL), Guanajuato, Mexico, in the last decade as a result of globalization especially productive restructuring and relocation of production activities by both TNCs and nationals enterprises. The MAL has become an area of attracting foreign direct investment, ie a 'growth pole', where the location of industrial activities is encouraged, and providing new investments, and the opportunity to exploit economies of scale reducing costs due to expansion and to merge with another companies. As a result has developed an economy called agglomeration geographic concentration of automakers and auto parts mainly in Silao, one of the municipalities that are part of the area. This agglomeration economy, has led to intense processes of competition between regions to attract investment, processes in which the State of Guanajuato has participated strongly and particularly MAL. The purpose of this paper is to examine the processes of economic restructuring of the area, and how has been developed the spatial and economic agglomeration, its impact on local economic growth, and competition generated between municipalities and other regions of the State of Guanajuato.

Studying developmental variation with Geometric Morphometric Image Analysis (GMIA).

The ways in which embryo development can vary across individuals of a population determine how genetic variation translates into adult phenotypic variation. The study of developmental variation has been hampered by the lack of quantitative methods for the joint analysis of embryo shape and the spatial distribution of cellular activity within the developing embryo geometry. By drawing from the strength of geometric morphometrics and pixel/voxel-based image analysis, we present a new approach for the biometric analysis of two-dimensional and three-dimensional embryonic images. Well-differentiated structures are described in terms of their shape, whereas structures with diffuse boundaries, such as emerging cell condensations or molecular gradients, are described as spatial patterns of intensities. We applied this approach to microscopic images of the tail fins of larval and juvenile rainbow trout. Inter-individual variation of shape and cell density was found highly spatially structured across the tail fin and temporally dynamic throughout the investigated period.

Spatial distribution and environmental determinants of denitrification enzyme activity in reed-dominated raised fields

Denitrification is an important process of nitrogen removal in lake ecosystems. However, the importance of denitrification across the entire soil-depth gradients including subsurface layers remains poorly understood. This study aims to determine the spatial pattern of soil denitrification enzyme activity (DEA) and its environmental determinants across the entire soil depth gradients in the raised fields in Baiyang Lake, North China. In two different zones of the raised fields (i.e., water boundary vs. main body of the raised fields), the soil samples from −1.0 m to 1.1 m depth were collected, and the DEA and following environmental determinants were quantified: soil moisture, pH, total nitrogen (TN), ammonia nitrogen (NH4+-N), nitrate nitrogen (NO3−-N), total organic carbon (TOC), and rhizome biomass of Phragmites australis. The results showed that the soil DEA and environmental factors had a striking zonal distribution across the entire soil depth gradients. The soil DEA reached two peak values in the upper and middle soil layers, indicating that denitrification are important in both topsoil and subsurface of the raised fields. The correlation analysis showed that the DEA is negatively correlated with the soil depth (p < 0.05). However, this phenomenon did not occur in the distance to the water edge, except in the upper layers (from 0.2 m to 0.7 m) of the boundary zone of the raised fields. In the main body of the raised fields, the DEA level remained high; however, it showed no significant relationship with the distance to the water edge. The linear regression analysis showed significant positive correlation of the DEA with the soil TN, NO3−-N, NH4+-N, and TOC; whereas it showed negative correlation with soil pH. No significant correlations with soil moisture and temperature were observed. A positive correlation was also found between the DEA and rhizome biomass of P. australis.

Does Medieval Trade Still Matter? Historical Trade Centers, Agglomeration and Contemporary Economic Performance

This study establishes a link between medieval trade, agglomeration and contemporary regional development in ten European countries. It documents a statistically and economically significant positive relationship between prominent involvement in medieval trade and regional economic development today. The analysis indicates that a long-lasting effect of medieval trade on contemporary regional development is indeed transmitted via its effect on agglomeration and industry concentration. Further empirical analyses show that medieval trade positively influenced city development both during the medieval period and in the long run; they also reveal a robust connection between medieval city growth and contemporary regional agglomeration and industry concentration. This research thus highlights the long-run importance of medieval trade in shaping the development of cities as well as the contemporary spatial distribution of economic activity throughout Europe. The path-dependent regional development processes caused by medieval commercial activities help explain the observed persistent regional development differences across the European countries considered.

Mapping inshore fisheries: Comparing observed and perceived distributions of pot fishing activity in Northumberland

Marine spatial planning (MSP) is increasingly promoted as part of an ecosystem-based approach to marine resource management. Impacts of MSP may be particularly great in inshore fisheries, yet despite their vulnerability, assessing potential impacts of spatial measures on inshore fisheries is limited by data scarcity, and the comparability of patterns of fishing activity produced by different data sources is poorly understood. This study contributes to the debate around information needs for MSP by describing the distribution of lobster potting activity at four ports in Northumberland, UK, using two sources of spatial data: observed fishing vessel sightings by patrol vessels and perceived fishing activity elicited through interviews with local fishers. The comparability of the distributions of potting activity mapped by the two datasets was explored using Mantel tests and overlap of fishing hotspots identified. Fishing activity at all ports tended towards an aggregated or patchy distribution, with hotspots located in inshore areas in close proximity to vessels׳ home ports. The two datasets were correlated at each port, though the strength of correlation varied among ports, being greater in ports with more highly aggregated fishing activity. Results suggest that vessel sightings are likely to better represent variable intensity of fishing activity, while interview data may more accurately capture the absolute extent of grounds important to fishers. This study highlights some of the merits and limitations of two available data sources currently used to inform fisheries management and marine conservation planning, and outlines an approach to assessing the consistency of datasets in describing the spatial distribution of activity. Given the limitations of individual datasets, we recommend triangulation of available data to inform MSP, alongside qualitative data on fishers׳ behaviour.

Power spectral aspects of the default mode network in schizophrenia: an MEG study.

BackgroundSymptoms of schizophrenia are related to deficits in self-monitoring function, which may be a consequence of irregularity in aspects of the default mode network (DMN). Schizophrenia can also be characterized by a functional abnormality of the brain activity that is reflected in the resting state. Oscillatory analysis provides an important understanding of resting brain activity. However, conventional methods using electroencephalography are restricted because of low spatial resolution, despite their excellent temporal resolution.The aim of this study was to investigate resting brain oscillation and the default mode network based on a source space in various frequency bands such as theta, alpha, beta, and gamma using magnetoencephalography. In addition, we investigated whether these resting and DMN activities could distinguish schizophrenia patients from normal controls. To do this, the power spectral density of each frequency band at rest was imaged and compared on a spatially normalized brain template in 20 patients and 20 controls.ResultsThe spatial distribution of DMN activity in the alpha band was similar to that found in previous fMRI studies. The posterior cingulate cortex (PCC) and lateral inferior parietal cortex were activated at rest, while the medial prefrontal cortex (MPFC) was deactivated at rest rather than during the task. Although the MPFC and PCC regions exhibited contrasting activation patterns, these two regions were significantly coherent at rest. The DMN and resting activities of the PCC were increased in schizophrenia patients, predominantly in the theta and alpha bands.ConclusionsBy using MEG to identify the DMN regions, predominantly in the alpha band, we found that both resting and DMN activities were augmented in the posterior cingulate in schizophrenia patients. Furthermore, schizophrenia patients exhibited decreased coherence between the PCC and MPFC in the gamma band at rest.

Changes in the spatial distribution of spawning activity by north-east Atlantic mackerel in warming seas: 1977–2010

Migratory species with a broad geographic range, such as north-east Atlantic mackerel, may be amongst the fauna most able to respond to warming seas, typically with a poleward shift in range. Habitat heterogeneity could, however, produce more complex patterns than a simple polewards translation in distribution. We tested for changes in the central location and spatial spread of mackerel spawning over a 33-year period. Spatial statistics [centre of gravity (CoG) of egg production, spatial variance, and degree of anisotropy] were used to summarise interannual changes in the spawning locations of the western spawning stock of north-east Atlantic mackerel (NEA-WSC) using data from the ICES triennial egg survey. A northwards shift in CoG of egg production estimates was observed, related to both an expansion in the distribution in survey effort and warming waters of the north-east Atlantic. Sea surface temperature (SST) had a significant positive association with the observed northward movement of NEA-WSC mackerel, equivalent to a displacement of 37.7 km °C−1 (based on spring mean SST for the region). The spatial distribution of spawning around the CoG also changed significantly with SST, with a less elongated spatial spread in warm years. An increase in the proportion of spawning over the Porcupine Bank demonstrated how habitat interacts with positional shifts to affect how north-east Atlantic mackerel are distributed around the centre of their spawning range.

Application of space-time scan statistics to describe geographic and temporal clustering of visible drug activity.

Knowledge of the geographic and temporal clustering of drug activity can inform where health and social services are needed and can provide insight on the potential impact of local policies on drug activity. This ecologic study assessed the spatial and temporal distribution of drug activity in Baltimore, Maryland, prior to and following the implementation of a large urban redevelopment project in East Baltimore, which began in 2003. Drug activity was measured by narcotic calls for service at the neighborhood level. A space-time scan statistic approach was used to identify statistically significant clusters of narcotic calls for service across space and time, using a discrete Poisson model. After adjusting for economic deprivation and housing vacancy, clusters of narcotic calls for service were identified among neighborhoods located in Southeast, Northeast, Northwest, and West Baltimore from 2001 to 2010. Clusters of narcotic calls for service were identified among neighborhoods located in East Baltimore from 2001 to 2003, indicating a decrease in narcotic calls thereafter. A large proportion of clusters occurred among neighborhoods located in North and Northeast Baltimore after 2003, which indicated a potential spike during this time frame. These findings suggest potential displacement of drug activity coinciding with the initiation of urban redevelopment in East Baltimore. Space-time scan statistics should be used in future research to describe the potential implications of local policies on drug activity.

The spatial distribution of economic activity in Melbourne, 1971–2006

This paper reports an empirical analysis of the distribution of employment by industry in Melbourne and how this changes over time. Depending on the nature of the industry being considered, two main patterns of spatial behavior are found, population-related dispersion and centralization. A methodology for estimating the benefits of centralization is developed and applied. Centralization benefits are highest for business services and other high-level services, supporting the view that the benefits of concentrating in the central business district are related to knowledge creation and exchange. Other forces, such as competitive pressure, land prices, and colocation with other industries, play only a minor role in determining the spatial distribution of industries, at least at the spatial levels used here. The implications of these findings are discussed.

Unravelling the relationship between Raman enhancement and photocatalytic activity on single anisotropic Au microplates.

Anisotropic noble-metal structures are attracting increasing attention because of interesting size- and shape-dependent properties and have emerging applications in the fields of optics and catalysis. However, it remains a significant challenge to overcome chemical contributions and acquire molecular insight into the relationship between Raman enhancement and photocatalytic activity. This study gives visualized experimental evidence of the anisotropic spatial distribution of Raman signals and photocatalytic activity at the level of single nanometer-thin Au microtriangles and microhexagons. Theoretical simulations indicate an anisotropic spatial distribution and sharpness-dependent strength of the electric-field enhancement. Analysis by using statistical surface-enhanced Raman scattering (SERS) supports this view, that is, Raman enhancement is on the order of corner>edge>face for a single microplate, but SERS measurements at different depths of focus also imply a concentration-dependent feature of SERS signals, especially at the corners and edges. Similarly, the SERS signals of product molecules in plasmonic photocatalysis also exhibit asymmetrical strengths at different corners of the same microplate. However, by examining the variations in the relative intensities of the SERS peaks, the difference in the photocatalytic activities at the corners, edges, and faces has been successfully calculated and is highly consistent with electric-field simulations, thus indicating that an increased number of molecules adsorbed at specific sites does not necessarily lead to a higher conversion ratio in noble-metal photocatalysis. Our strategy weakens the assumed impact of plasmonic local heating and, to a certain extent, excludes the influence of concentration effects and chemical contributions in noble-metal photocatalysis, thus clearly profiling plasmon-related characteristics. This study also promises a new research direction to understand the enhancement mechanism of SERS-active structures.

Object-Centered Shifts of Receptive Field Positions in Monkey Primary Visual Cortex

Stimuli that project the same retinal visual angle can appear to occupy very different proportions of the visual field if they are perceived to be at different distances [1-8]. Previous research shows that perceived angular size alters the spatial distribution of activity in early retinotopic visual cortex [7, 9-11]. For example, a sphere superimposed on the far end of a corridor scene appears to occupy a larger visual angle and activates a larger region of primary visual cortex (V1) compared with the same sphere superimposed on the near end of the corridor [7]. These previous results, however, were obtained from human subjects using psychophysics and fMRI, a fact that fundamentally limits our understanding of the underlying neuronal mechanisms. Here, we present an animal model that allows for a finer examination of size perception at the level of single neurons. We first show that macaque monkeys perceive a size-distance illusion similarly to humans. Then, using extracellular recordings, we test the specific hypothesis [12] that neurons in V1 shift the position of their receptive fields (RFs) in response to complex monocular depth cues. Consistent with this hypothesis, we found that when ring-shaped stimuli appeared at the back of the corridor, RFs of V1 neurons shifted toward the center of the rings. When the same stimuli appeared at the front of the corridor, RFs shifted outward. Thus, our results show for the first time that V1 RFs can shift, potentially serving as the neural basis for the perception of angular size.

222Rn activity in groundwater of the St. Lawrence Lowlands, Quebec, eastern Canada: relation with local geology and health hazard

One hundred ninety-eight groundwater wells were sampled to measure the 222Rn activity in the region between Montreal and Quebec City, eastern Canada. The aim of this study was to relate the spatial distribution of 222Rn activity to the geology and the hydrogeology of the study area and to estimate the potential health risks associated with 222Rn in the most populated area of the Province of Quebec. Most of the groundwater samples show low 222Rn activities with a median value of 8.6Bq/L. Ninety percent of samples show 222Rn activity lower than 100Bq/L, the exposure limit in groundwater recommended by the World Health Organization. A few higher 222Rn activities (up to 310Bq/L) have been measured in wells from the Appalachian Mountains and from the magmatic intrusion of Mont-Saint-Hilaire, known for its high level of indoor radon. The spatial distribution of 222Rn activity seems to be related mainly to lithology differences between U-richer metasediments of the Appalachian Mountains and magmatic intrusions and the carbonaceous silty shales of the St. Lawrence Platform. Radon is slightly enriched in sodium-chlorine waters that evolved at contact with clay-rich formations. 226Ra, the parent element of 222Rn could be easily adsorbed on clays, creating a favorable environment for the production and release of 222Rn into groundwater. The contribution of groundwater radon to indoor radon or by ingestion is minimal except for specific areas near Mont-Saint-Hilaire or in the Appalachian Mountains where this contribution could reach 45% of the total radioactive annual dose.

Challenges in using ¹⁸F-fluorodeoxyglucose-PET-CT to define a biological radiotherapy boost volume in locally advanced pancreatic cancer.

BackgroundThe best method of identifying regions within pancreatic tumours that might benefit from an increased radiotherapy dose is not known. We investigated the utility of pre-treatment FDG-PET in predicting the spatial distribution of residual metabolic activity following chemoradiotherapy (CRT) in locally advanced pancreatic cancer (LAPC).Methods17 patients had FDG-PET/CT scans at baseline and six weeks post-CRT. Tumour segmentation was performed at 40% and 50% of SUVmax at baseline and 60%, 70%, 80% and 90% post-CRT. FDG-PET scans were non-rigidly registered to the radiotherapy planning CT using the CT component of the FDG-PET/CT. Percentage overlap of the post-CRT volumes with the pre-CRT volumes with one another and the gross tumour volume (GTV) was calculated.ResultsSUVmax decreased during CRT (median pre- 8.0 and post- 3.6, p < 0.0001). For spatial correlation analysis, 9 pairs of scans were included (Four were excluded following complete metabolic response, one patient had a non-FDG avid tumour, one had no post-CRT imaging, one had diffuse FDG uptake that could not be separated from normal tissues and one had an elevated blood glucose). The Pre40% and 50% of SUVmax volumes covered a mean of 50.8% and 30.3% of the GTV respectively. The mean% overlap of the 90%, 80%, 70%, 60% of SUVmax post-CRT with the Pre40% and Pre50% volumes were 83.3%, 84.0%, 83.7%, 77.9% and 77.8%, 69.9%, 74.5%, 64.8% respectively.ConclusionsRegions of residual metabolic activity following CRT can be predicted from the baseline FDG-PET and could aid definition of a biological target volume for non-uniform dose prescriptions.