Spatial Distribution Of Activity Research Articles

Remote sensing of deep convection within a tropical‐like cyclone over the Mediterranean Sea

The Mediterranean basin occasionally hosts tropical‐like cyclones named “Medicanes”. Medicanes may have intensity comparable to hurricanes in terms of wind speeds along with an axisymmetric cloud structure. Although these events can be particularly violent, very few studies so far have investigated the distribution and temporal evolution of deep convection within these cyclones. In this study, the characteristics and lifetime of deep convection and lightning activity surrounding the core of the longest‐lasting and probably the most intense Medicane ever recorded in terms of wind speed (Rolf, November 2011) are presented by all available means of microwave and infrared satellite retrievals and a lightning detection system. Results showed that deep convective clouds penetrated the lowest stratosphere and were wrapped around the cyclone centre during the intensification period. Lightning activity was mostly active about a day before the maximum strength of the cyclone studied and it was not temporarily correlated with the most intense deep convection activity. Overall, this study reveals that spatial and temporal distribution of deep convection and lightning activity around the centre of Rolf show more similarities with Tropical Cyclones than intense Mediterranean cyclones.

PATHOMORPHOSIS OF FOCAL EPILEPSY AND ITS NEUROPHYSIOLOGICAL CORRELATES

The specific EEG patterns in patients with epilepsy enable the objective assessment of changes in the brain function and, in conjunction with clinical data, determine the efficacy of treatment. Characteristics of the EEG spectral power have additional diagnostic values as they reflect the severity and spatial distribution of epileptiform activity. The standard EEG analysis combined with further mathematical processing helps reveal the neurophysiological markers of resistance to anti-epileptic drugs. The aim is to identify the neurophysiological correlates of drug-resistance. Materials and methods . We examined 160 patients with epilepsy: 80 with drug-resistant epilepsy (DRE) and 80 with controlled epilepsy (CE). The subjects underwent a number of neurophysiological studies (EEG, EEG-video monitoring) including the spectral power analysis. Results . We established a correlation between the paroxysmal activity localization and drug-resistance. The secondary bilateral synchronization syndrome of different degrees of severity was found in the DRE group 1.91 times more often than in the CE group; this syndrome is seen as an unfavorable factor aggravating the course of epilepsy in the DRE patients. Using the spectral analysis we also found that patients with DRE differed from those with CE by the types of paroxysmal activity in the frontal-occipital areas. There, the involvement of diencephalic and mesencephalic structures in the paroxysms were similar in the DRE group, while only diencephalic structures played a significant role in the paroxysmal activity in CE patients. Conclusion . Neurophysiological factors correlating with resistance to antiepileptic drugs in patients with epilepsy were identified. The results can be used for the timely diagnosis of pathomorphism of epilepsy and the choice of therapy.

Variability and geologic associations of volcanic activity on Io in 2001–2016

Since the end of the Galileo epoch, ground-based observations have been crucial for the continued monitoring and characterization of volcanic activity on Jupiter’s moon, Io. We compile and analyze observations from the Keck and Gemini North telescopes between 2001 and 2016, including new and published observations from 2003, 2004, 2005, 2007, 2008, 2009, 2011, 2012, 2013, and 2016. A total of 88 distinct hot spot sites were detected over the 15-year period, 82 of which were detected multiple times, and 24 of which were not detected by Galileo at thermal infrared wavelengths (1–5 µm). A variety of analytical methods are utilized to investigate the detections of active volcanism as a surface expression of interior heating. Geologic associations of hot spots, including patera type, lava flow type, and proximity to mountainous regions, are made using the USGS-published global geologic map of Io (Williams, 2011). We also provide a summary of outburst-scale events, along with the slightly less bright but more frequent, mini-outbursts described by de Kleer and de Pater (2016a).We investigate the spatial distribution of volcanic activity on Io using nearest neighbor, mean pairwise spacing, and mean latitude statistics with various classification schemes. The analysis confirms previous findings in that the heat dissipation appears to be primarily concentrated in the asthenosphere resulting in a high time-averaged surface heat flux at low latitudes. Our observations show significant spatial deviations do exist from the asthenosphere heat dissipation model while also suggesting a deeper source of magma ascent to be present as well, supporting conclusions from previous analyses of primarily spacecraft data (Veeder et al., 2012; Hamilton, 2013; Davies et al., 2015). From a temporal perspective, there are signs of significant variations in the distribution of global heat flux, as volcanoes undetected, and probably dormant, during the Galileo encounters subsequently erupted and remained active during our observations. We also use the on 3.8-µm radiant intensity timelines of individual hot spots, along with the distribution of extensive lava fields in relation to detected activity, as a means to investigate possible connections between hot spots and short timescale, spatio-temporal variations in the global heat flux distribution. We conclude that while the global heat flux distribution remains relatively constant over decadal timescales, there is evidence that significant deviations do occur potentially as a result of mountain forming processes or triggering mechanisms between eruptions.

Industry location and wages: The role of market size and accessibility in trading networks

We analyze the effects of local market size and accessibility on the spatial distribution of economic activity and wages in general equilibrium trade models with many asymmetric countries and costly trade for all goods. In models with a homogeneous sector, local market size is generally more strongly correlated with a country's industry share, whereas accessibility better explains a country's wage. We analytically show that result in a simplified case and then confirm it using simulations with random trading networks. In models with only differentiated sectors, both local market size and accessibility are highly correlated with wages. The impact of local market size on industry location is more robust than the impact of local market size on wages in economic geography models.

Geography, human capital and urbanization: A regional analysis

Using subnationally representative data for 679 regions from 64 low- and middle-income countries, we document that geography, especially trade-related features, explains a substantial share of within-country variation in the level of human capital. We further show that a large part of the explanatory power can be attributed to the close interrelation between urbanization and concentration of human capital. These results bring together studies that identify human capital as an important determinant of regional development and the literature on economic geography that emphasizes geography’s role in shaping the spatial distribution of urbanization and economic activity.

Ukrainian segment of the ENTLN (LIGHTNING FINDING SYSTEM)

The Ukrainian segment of the Earth Networks lightning finding system created in 2016 is dis-cussed in the paper. It consists of 12 sensors located in different parts of Ukraine which allow identifying both types of lightning: "cloud-to-ground discharge (CG)" and "cloud-to-cloud dis-charge (CC)". The stated number of sensors covers the entire territory of Ukraine and allows the determination of CG with a probability of 95 % with the spatial accuracy of lightning detection constituting about 200 meters. Taking into account the necessity to preserve the equipment, an agreement was reached with the Ukrainian Hydrometeorological Centre on installation of light-ning finding sensors within the territory of meteorological stations. Significant advantage of this lightning finding system is that it allows recording of electromagnetic lightning signals within the range from 1 Hz to 12 MHz. Due to this, the spatial position of CG and CC can be determined more accurately by analyzing the spectrum of electromagnetic signal within the specified range. To localize a lightning discharge using the ENTLN network the method of lightning finding based on the principle of "time of signal arrival (ToA)" is applied. The primary data obtained from the lightning finding sensors are analyzed in the internal system of centralized processing and can be used further by a consumer in two ways: either directly, or serve as output data for series of prod-ucts resulted from processing using mathematical, statistical and geographic information systems. In order to process obtained data the UHMI developed a modular system that allows unification of the means of primary and secondary processing of output data and enabling all necessary channels for transmission of generated data using a wide range of protocols. To visualize the lightning data a subsystem based on the open GeoServer for preprocessing of the geodata and client tools using the mapping data of OpenStreetMap are used. As an example of one of possibilities these lightning data provide, the analysis of the spatial and temporal distribution of lightning activity over the ter-ritory of Ukraine from June 10 to September 30, 2016 has been done and the results showed that these data could be a new, qualitative source of data for climatological studies. In addition, real-time data acquisition allows creation of a series of products for a wide range of consumers inter-ested in a short-term forecasting.

Intra-operative characterisation of subthalamic oscillations in Parkinson’s disease

ObjectiveThis study aims to use the activities recorded directly from the deep brain stimulation (DBS) electrode to address the focality and distinct nature of the local field potential (LFP) activities of different frequency. MethodsPre-operative and intra-operative magnetic resonance imaging (MRI) were acquired from patients with Parkinson’s disease (PD) who underwent DBS in the subthalamic nucleus and intra-operative LFP recording at rest and during cued movements. Images were reconstructed and 3-D visualized using Lead-DBS® toolbox to determine the coordinates of contact. The resting spectral power and movement-related power modulation of LFP oscillations were estimated. ResultsBoth subthalamic LFP activity recorded at rest and its modulation by movement had focal maxima in the alpha, beta and gamma bands. The spatial distribution of alpha band activity and its modulation was significantly different to that in the beta band. Moreover, there were significant differences in the scale and timing of movement related modulation across the frequency bands. ConclusionSubthalamic LFP activities within specific frequency bands can be distinguished by spatial topography and pattern of movement related modulation. SignificanceAssessment of the frequency, focality and pattern of movement related modulation of subthalamic LFPs reveals a heterogeneity of neural population activity in this region. This could potentially be leveraged to finesse intra-operative targeting and post-operative contact selection.

Shaking Up the Equilibrium: Natural Disasters, Economic Activity, and Immigration

This paper examines the long-run effects on the spatial distribution of economic activity caused by historical shocks. Using variation in the potential damage intensity of the 1906 San Francisco Earthquake across cities in the American West, we show that more severely affected cities experienced lower population growth relative to less affected cities after the earthquake. This negative effect persisted until the late 20th century. The earthquake diverted migrants to less affected areas in the region, which, together with reinforcing dynamic agglomeration effects from scale economies, left a long-lasting mark on the location of economic activity in the American West.

Mapping of polycrystalline films of biological fluids utilizing the Jones-matrix formalism

Utilizing a polarized light approach, we reconstruct the spatial distribution of birefringence and optical activity in polycrystalline films of biological fluids. The Jones-matrix formalism is used for an accessible quantitative description of these types of optical anisotropy. We demonstrate that differentiation of polycrystalline films of biological fluids can be performed based on a statistical analysis of the distribution of rotation angles and phase shifts associated with the optical activity and birefringence, respectively. Finally, practical operational characteristics, such as sensitivity, specificity and accuracy of the Jones-matrix reconstruction of optical anisotropy, were identified with special emphasis on biomedical application, specifically for differentiation of bile films taken from healthy donors and from patients with cholelithiasis.

Vascularity and VEGF/VEGFR2 Signaling in the Dentine-Pulp Complex of Immature and Mature Permanent Teeth.

Objective:To examine the microvessel density (MVD) and spatial distribution of endothelial cells and angiogenic activity in immature and mature permanent teeth using immunohistochemistry.Methods:Healthy third molars with immature and mature root development were formalin-fixed, decalcified in 10% ethylenediaminetetraacetic acid, and processed for routine immunohistochemistry with endothelial cell markers anti-CD34 and anti-CD146 and angiogenic markers anti-vascular endothelial growth factor (VEGF) and anti-VEGF receptor-2 (VEGFR2). Staining was visualized with diaminobenzidine and examined using light microscopy. The distribution of markers was analyzed qualitatively and quantitatively in the coronal, middle, and apical regions of the dentine–pulp complex.Results:There were spatial differences in protein expression for immature and mature teeth. The pulps of immature teeth were more vascular, had a greater number of CD34+ and CD146+ cells, and a significantly higher MVD in the coronal region than those of mature teeth (P=0.03). The apical papilla contained few blood vessels. VEGF/VEGFR2 activity was significantly greater for immature teeth (P=0.001). VEGF was expressed throughout the pulp–dentine complex, but there was significantly more growth factor coronally (immature P=0.04 and mature P=0.02). VEGFR2 was expressed less than VEGF but was seen on the endothelial cells and single cells unrelated to a vessel lumen.Conclusion:The spatial distribution of vascular and angiogenic (VEGF/VEGFR2) markers indicates the potential for altered healing responses in the pulps of immature and mature teeth. Immature teeth have a greater MVD and VEGF/VEGFR2 expression than mature teeth, and the increased expression of these markers in the coronal region of both tooth types is important for pulp healing.

Spatial patterns of enzyme activities in the rhizosphere: Effects of root hairs and root radius

The importance of root hairs and root radius for exudation and nutrient acquisition by plants is known mainly from nutrient solution studies. The in situ effects of root hairs and root radius on the spatial distribution of enzyme activity in the rhizosphere of various plants are unknown. Four plants with contrasting root morphology (maize, wheat, lentil and lupine) were chosen to test the effects of root hairs and root radius on the spatial distribution of β-glucosidase, cellobiohydrolase, leucine aminopeptidase and acid phosphatase. We combined zymography with enzyme kinetics to evaluate the effects of root hairs on the rhizosphere extent and on substrate turnover. The extent of enzyme activity in the rhizosphere of four plants ranged from 0.55 to 2 mm. The extent of β-glucosidase was 1.5 times broader (1.2 mm versus 0.8 mm) and the substrate turnover was 2-fold faster around wheat root regions with hairs than hairless locations. The rhizosphere extent relative to root radius and the enzyme activity per root surface area were plant and enzyme specific: the rhizosphere extent was 1.5–2 times broader and the enzyme activity was 2–8-fold higher in wheat (with thin roots and long root hairs) compared to maize, lentil and lupine. The rhizosphere extent of acid phosphatase (1.1–2.0 mm) was 1.5–2-fold broader than that of other enzymes (0.5–1.0 mm). For the first time, we showed that the rhizosphere extent relative to root radius was 20–100% broader and enzyme activity per surface area was 4–7-fold higher around thin roots (wheat) than around thick roots (maize). Moreover, the rhizosphere extent relative to root radius was 10–30% broader and enzyme activity per root area was 2–7 times higher around roots with long and dense hairs (lupine) than around roots with short and sparse hairs (lentil). We conclude that root hairs and root radius shape the rhizosphere: root hairs contributed mainly to the rhizosphere extent, while root radius more strongly affected the enzyme activity per root surface area.

International isolation and regional inequality: Evidence from sanctions on North Korea

This paper examines how the spatial distribution of economic activity evolved within North Korea during a period of economic sanctions. Countries have used economic sanctions to isolate North Korea from the benefits of international trade and finance. China, however, has not imposed the sanctions, and consequentially has offset the trade restrictions imposed by other countries. I hypothesize three channels by which North Korea could have responded in this context: regional favoritism by the ruling elites, reallocation of commerce that reflects the trade diversion to China, and import substitution. Using nighttime lights from North Korea, I find that the capital city, trade hubs near China, and manufacturing cities become relatively brighter when sanctions increase. However, production shifts away from capital-intensive goods, potentially deterring industrial development. The results imply that despite the intention to target the ruling elites, sanctions may increase regional inequality at a cost to the already marginalized hinterlands.

Making the most of data-poor fisheries: Low cost mapping of small island fisheries to inform policy

Data scarcity in small-scale fisheries hinders the effective management of marine resources. This is particularly true within small island developing states that often have limited capacity for monitoring activities that could inform policy decisions. This study estimates the spatial distribution of fishing activity in the data-poor nearshore reef fisheries of Barbados using low cost interview surveys of fishers combined with a geospatial platform. With data from over 150 fishers in the island's major reef fisheries, the estimated total annual yield ranged from 272.6 to 409.0mt, with seine fishing accounting for 65% of landings. This estimate is substantially higher than the recorded landings in official databases. Fishing activity is concentrated on the sheltered and heavily populated West Coast of the island. Reef fishing effort decreases markedly during the months associated with the offshore pelagic fishery season, as many fishers switch fisheries during this time and rough sea conditions restrict access to the nearshore windward reefs. The high levels of fishing intensity and low yields per unit of reef area appear to validate anecdotal evidence that the nearshore reefs of Barbados are heavily overexploited. The qualitative nature of interview data and other data gaps hinder the precise estimation of fishing effort and yield, where relative values are likely to be more accurate than absolute values. Nonetheless, the spatially and temporally explicit data generated here demonstrates how simple cost-effective methods can be used to fill important information gaps for marine resource management and spatial planning.

Muscle Pain Induces a Shift of the Spatial Distribution of Upper Trapezius Muscle Activity During a Repetitive Task: A Mechanism for Perpetuation of Pain With Repetitive Activity?

An association exists between repetitive movements and the development or perpetuation of neck-shoulder muscle pain. The mechanisms underlying this association remain unclear. This observational study investigated the effect of upper trapezius muscle pain on the distribution of upper trapezius activity during repetitive lifting. It was hypothesized that nociception would change the distribution of activity resulting in activation of muscle regions which would not normally be active during the task. Healthy men repeatedly lifted a box with a cycle time of 3 seconds for 50 cycles, at baseline, following injection of isotonic and hypertonic saline into the upper trapezius muscle and 15 minutes after the last injection. High-density surface electromyography (EMG) was recorded from the upper trapezius using a grid of 64 electrodes. The EMG amplitude was computed for each location to form a map of the EMG amplitude distribution. During the painful condition, the overall EMG amplitude was lower compared with all other conditions (P<0.05) and in addition, the center of upper trapezius activity was shifted toward the caudal region of the muscle (P<0.01), a region not normally active during the task. The described alterations of muscle activity likely play an important role in the perpetuation of pain during repetitive activity. Novel mapping of the spatial distribution of upper trapezius muscle activity showed that nociception induced a redistribution of activity during repetitive lifting. This knowledge provides new insights into the mechanisms underlying the perpetuation of pain with repetitive activity.

Spatial heterogeneity in white-tailed deer activity increases seed dispersal of shade-intolerant plants near forest edges in fragmented forests

Seed dispersal structures plant populations and communities but may be affected by forest fragmentation. Recent work demonstrates that white-tailed deer (Odocoileus virginianus Zimmerman) can be important seed dispersers in North American forests, potentially moving seeds over long distances. However, little is known about the role of deer as seed dispersal agents in landscapes characterized by small, isolated forest patches. The objectives of this study were to (a) determine how habitat structure influenced the spatial distribution of deer activity, and (b) describe which plant species and traits were dispersed by deer in a highly fragmented, agricultural matrix. I collected deer fecal pellet groups from 10 forest patches in plots that ranged from 10 to 100 m from forest edge. Pellet groups were cold-stratified and planted in a greenhouse to quantify seeds dispersed by deer. The number of pellet groups collected was highest near forest edges but was not influenced by patch size or isolation; 258 seedlings from 15 species emerged from collected pellets, with three species contributing 80% of seedlings. Most seedlings emerging from deer pellets were herbaceous, nonnative plants with a foliage-as-fruit dispersal mode. Plants with these traits typically perform well in high-light habitats, such as forest edges, where deer are most active. These results suggest that while seed dispersal by deer is common in highly fragmented forest patches, it is most likely to benefit shade-intolerant herbaceous species, maintaining populations of those plants along forest edges.

Identificación de Tareas Isométricas y Dinámicas del Miembro Superior Basada en EMG de Alta Densidad

Identification of tasks and estimation of volitional movement based on electromyography (EMG) constitute a known problem that involves different areas in the field of expert systems and particularly pattern recognition, with many possible applications in assistive and rehabilitation devices. The obtained information can be very useful to control exoskeletons or robots used in active rehabilitation processes. The emerging technology of high-density electromyography (HD-EMG) opens up new possibilities to extract neural information, and it has already been reported that the spatial distribution of HD-EMG intensity maps is a valuable feature in the identification of isometric tasks.This study explores the use of the spatial distribution of myoelectric activity and carries out a task identification during dynamic exercises at different velocities which are much closer to the ones commonly used during therapy. To this end, HD-EMG signals were recorded in a group of healthy subjects while performing a set of isometric and dynamic upper limb tasks. The results show that spatial distribution is a very useful feature in the identification not only of isometric contractions but also of dynamic contractions, so it can be very useful to improve the control of rehabilitation devices, making it more natural and permitting to adapt better to the user.

On the new economic geography of a multicone world

AbstractWe build a new economic geography model incorporating differences in productivity among sectors and countries, thus allowing for comparative advantage. We study the role that market size, absolute advantage, and comparative advantage have on the trade patterns and the long‐run spatial distribution of economic activity in a world with multicones of specialization. We briefly mention the possibility of long‐term fluctuations in the spatial distribution of industry by relying on a discrete‐time framework.

Modeling agglomeration and dispersion in space: The role of labor migration, capital mobility and vertical linkages

AbstractIn this paper we investigate the role played by capital mobility, labor migration and input–output linkages in shaping the spatial distribution of economic activity in a spatial computable general equilibrium framework. We identify European Union core and periphery regions based on an accessibility index and simulate the impact of a homogeneous transport shock. Our results suggest that agglomeration patterns are magnified by labor and capital mobility, the latter exerting a stronger influence than the former. Results are more nuanced for vertical linkages, which are associated with more agglomeration in terms of GDP, but more dispersion in terms of number of firms and labor demand. These results shed additional light on location mechanisms in applied general equilibrium applications of the new economic geography (NEG) theory and complement the theoretical NEG literature based on analytically solvable models.

THE GLOBAL DISTRIBUTION OF ECONOMIC ACTIVITY: NATURE, HISTORY, AND THE ROLE OF TRADE.

We explore the role of natural characteristics in determining the worldwide spatial distribution of economic activity, as proxied by lights at night, observed across 240,000 grid cells. A parsimonious set of 24 physical geography attributes explains 47% of worldwide variation and 35% of within-country variation in lights. We divide geographic characteristics into two groups, those primarily important for agriculture and those primarily important for trade, and confront a puzzle. In examining within-country variation in lights, among countries that developed early, agricultural variables incrementally explain over 6 times as much variation in lights as do trade variables, while among late developing countries the ratio is only about 1.5, even though the latter group is far more dependent on agriculture. Correspondingly, the marginal effects of agricultural variables as a group on lights are larger in absolute value, and those for trade smaller, for early developers than for late developers. We show that this apparent puzzle is explained by persistence and the differential timing of technological shocks in the two sets of countries. For early developers, structural transformation due to rising agricultural productivity began when transport costs were still high, so cities were localized in agricultural regions. When transport costs fell, these agglomerations persisted. In late-developing countries, transport costs fell before structural transformation. To exploit urban scale economies, manufacturing agglomerated in relatively few, often coastal, locations. Consistent with this explanation, countries that developed earlier are more spatially equal in their distribution of education and economic activity than late developers.

On the seasonal variability and the spatial distribution of lightning activity over the broader Greek area and their connection to atmospheric circulation

The spatio-temporal regime of lightning strokes over the broader Greek area is studied using 15-day ZEUS cloud-to-ground lightning data for a 10-year period (2005–14). The multivariate statistical method Factor Analysis (S-mode and T-mode) is applied on the mean intra-annual variation of lightning in order to reveal: i) the main modes of intra-annual variation of lighting activity that correspond to specific sub-regions of the Greek area and ii) the main characteristic patterns of strokes prevailing during specific periods of the year (“seasons”). According to the results there are three main modes of intra-annual variation: a) the continental one with maximum lightning activity in early summer, b) the Ionian Sea one with maximum in early autumn and c) the Aegean Sea one with maxima in middle autumn and late May. Also, according to the patterns of strokes, three main “seasons” are found: a) the summer one (early May–middle August) with highest lightning activity over the continental regions of the country due to the atmospheric instability associated with the intense land heating and the persistence of cool upper air masses, b) the winter one (middle December–middle February) with the maximum of lightning activity over the sea where instability is high due to the frequent prevalence of cold air masses over the warm sea-surface and the associated passages of Mediterranean depressions and c) the autumn one (early September–middle October) with maximum over northwestern Greece associated with the early cold season low pressure systems, the warm sea body of Ionian Sea and the essential role of topography.