Latitudinal Direction Research Articles

Разнообразие широколиственных и сосново-широколиственных лесов на восточной границе их распространения

Разнообразие широколиственных и сосново-широколиственных лесов на восточной границе их распространения

Analysis of hyperboloid cooling tower projection on 2D shape

This paper undertakes the problem of mapping a hyperboloid cooling tower on a single plane. Measurements performed by ground-based laser scanning technology quickly deliver substantial amounts of geometric data of the tower’s outer wall. The essence of the article is projection of the rotational hyperboloid on a plane. The shape of the hyperboloid cooling tower is not directly expandable to a single plane. Mapping a hyperboloid shape on a plane is, therefore, associated with distortions. This paper presents a comparison between cylindrical and conic projection of a hyperboloid cooling tower. The most popular method of mapping hyperboloid is cylindrical projection. The cylinder’s side surface is easily developed on the drawing sheet. For the hyperboloid cooling tower, the biggest distortions occur in the latitudinal direction and reach the highest values at the top and bottom edges. The equation (13) describe distortion for the cylindrical projection. The equation (18) describe distortion for the conical projection. This paper presents results obtained from the performed measurement. The analysis found that cone mapping produces less distortion than cylindrical projection for the hyperboloid cooling tower. We think, that in conical projection, the shape of a hyperboloid cooling tower and theoretical conic shape have better corresponding together than in cylindrical projection.

СУЧАСНИЙ СТАН ТА ПЕРСПЕКТИВИ РОЗВИТКУ ТРАНСПОРТНОЇ ІНФРАСТРУКТУРИ В УКРАЇНІ

The article considers modern condition and development perspectives of transport at whole and the transport infrastructure of Ukraine. The basis of the country transport complex makes up its infrastructure, it joins manufacturing, users, suppliers and partners. Developed infrastructure affects not only effective and timely delivery of the products, but provides for decreased transport expenses. The beneficial geographical position of Ukraine, crossing the main transit ways between Europe and Asia, presence of active Black Sea ports, developed network of railroads, car roads and pipelines throughout the latitudinal and meridian directions create all predispositions for the transport branch development. The studies of the Ukrainian transport infrastructure and transport condition during last years evidence about non-stable dynamics, which is mainly related to economical and geopolitical crisis in the country as well as the COVID 19 consequences. Analysis of the freight transport by transport kinds shows increased volumes of car transport with decreased railway transport. The rise of the car transport share is connected to its advantages: mobility, possibility of delivery exactly to the destination, high speed of delivery, flexibility of the route choice, wide range of the shipment as well as provision of logistic services by cars. Exacerbation in the East has considerably decreased number of contracts between Ukrainian shipping companies and international partners related to the international transportation. First of all, the situation provides for decreased transportation volumes on the territory of Ukraine. The level of transport services to economic system and population of Ukraine is significantly lower than that one in the developed countries of the world. According to the car road characteristics, Ukraine has long been behind not only the countries of Western Europe, but many post-Soviet countries. A necessary condition of the effective development and managing crisis in the transport branch, particularly that caused by the COVID 19 pandemics, is development and modernizing transport infrastructure of Ukraine according to the modern technological requirements. This will provide for uniform development of all regions of Ukraine, improved population life quality, development of trade and tourism as well as creation of new economic opportunities by attracting foreign investment.

Instantaneous angular velocity of quantum evolution

We introduce a metric in a geometric way for measuring the distance between two quantum states and derive the instantaneous angular velocity of a quantum state's dynamical evolution, which has two components: $\mathrm{\ensuremath{\Delta}}{E}_{t}/\ensuremath{\hbar}$ in the longitudinal direction and ${\overline{E}}_{t}/\ensuremath{\hbar}$ in the latitudinal direction. By applying the instantaneous angular velocities in the dynamical evolution governed by a time-independent Hamiltonian, the fastest way for a pure state to evolve to a target state is discussed. As a consequence, we generalize the Mandelstam-Tamm and Margolus-Levitin bounds without using the Heisenberg uncertainty relation and point out the conditions for saturating the two bounds. The fastest dynamical evolution of a quantum system with a particular time-dependent Hamiltonian is also briefly discussed. The quantum features in the dynamical evolution are revealed through phase change and lifetime of the initial state.

URBAN PLANNING TRANSFORMATION OF FUNCTIONAL PLANNING STRUCTURE OF SUBURBAN ZONES AND BELTS OF MEGAPOLIS. FOREIGN EXPERIENCE

The article considers the features of the functional planning structure transformation of North American megalopolises in the context of the construction of inland railways. The subject of inquiry is the territories of the sett lement system formation in North America from the beginning of colonial invasions, where the interests of Great Britain, France and Spain intersected to the current stage of megacities. There is investigated the infl uence of railway transport on the development of megacities in North America. The subject of research is the Canadian Pacifi c Railroad and the US Transcontinental Railroad, which contributed to the countries urbanization and industrialization. The prerequisites for the transformation of suburban areas were the intensity of labor, cultural, household and industrial links between the center and the periphery in the meridional and latitudinal directions, formation of new kind of scientifi c and industrial complexes, multi-nodes, its infl uence on the functional planning structure of suburban areas and outskirts of megacities. The article introduces the concept of “multi-node”. Multi-nodes are multifunctional urban development complexes with transport infrastructure and engineering facilities which form a complex of terminals for goods transshipment and passengers transferring from one kind of transport to another, as well as public spaces integrated into the urban environment, scientifi c and innovative enterprises with full autonomy and communication that provides the megalopolis with energy resources. Multi-node complexes are located closely to each other and form an integral group, most often around the near-airport territories. This group may not have clear planning boundaries in the form of streets, driveways, fences, and so on. The purpose of the research is to study the sequence of the functional and planning structure formation of the city in dynamics. At the initial stage, from the linear structure of the city along the railway to a more complex ray system, and in the future - the formation of the ring type planning structures, that provide switching of traffi c fl ows on all azimuths directions. It is planning to be constructed a theoretical model of interaction between subcentres and multi-nodes in the suburban zones of intracontinental megacities.

Statistical Properties of Electron Curtain Precipitation Estimated With AeroCube-6.

Curtain precipitation is a recently discovered stationary, persistent, and latitudinally narrow electron precipitation phenomenon in low Earth orbit. Curtains are observed over consecutive passes of the dual AeroCube‐6 CubeSats while their in‐track lag varied from a fraction of a second to 65 s, with dosimeters that are sensitive to ‐keV electrons. This study uses the AeroCube‐6 mission to quantify the statistical properties of 1,634 curtains observed over 3 years. We found that many curtains are narrower than 10 km in the latitudinal direction with 90% narrower than 20 km. We examined the geographic, magnetic local time, and geomagnetic dependence of curtains. We found that curtains are observed in the late‐morning and premidnight magnetic local times, with a higher occurrence rate at premidnight, and curtains are observed more often during times of enhanced Auroral Electrojet. We found a few curtains in the bounce loss cone region above the North Atlantic, whose electrons were continuously scattered for at least 6 s. Such observations suggest that continuous curtain precipitation may be a significant loss of ‐keV electrons from the magnetosphere into the atmosphere. We hypothesize that the curtains observed in the bounce loss cone were accelerated by parallel electric fields, and we show that this mechanism is consistent with the observations.

Estimating seasonal water budgets in global lakes by using multi-source remote sensing measurements

The seasonal change in lake water storage (LWSsc) reflect periodic fluctuations of the basin-scale water balance. However, the role of LWSsc in regulating the water budget at the global scale has not yet been investigated based on straight-forward observations. Quantifying LWSsc is necessary, especially under the context of global change. Available in-situ measurements of lake water levels and volumes are still scarce. Therefore, the Global Surface Water datasets of Joint Research Centre and multi-source satellite altimetry datasets through mathematical statistics methods are used in this study to address this issue. We estimate the LWSsc of 463 lakes and reservoirs worldwide with areas greater than 10 km2, which represent nearly 64% of the total global lake area and 93% of the total lake volume capacity. Results show that the global seasonal water storage variation of these examined water bodies is 1390.91 ± 78.91 km3, comprising 869.44 ± 67.35 km3 from lakes and 521.46 ± 41.11 km3 from reservoirs. The relatively large estimates of LWSsc are concentrated in North American and African basins. Among the watersheds, the seasonal fluctuations of lakes in the North American Lawrence basin make up the most substantial magnitude of 10.76% of the global LWSsc. The latitudinal direction zonality of LWSsc is relatively significant. The LWSsc is concentrated between 30° N and 60° N in the northern hemisphere and between the equator and 30° S in the southern hemisphere. Considering the geographic similarity and climatological zonality, the global LWSsc estimates are also extrapolated to other lakes without direct satellite altimetry observations on the basis of the average rate of the examined lakes distributed in the same Köppen − Geiger Climate Classification zones. The LWSsc is calculated with a consequence of 488.23 ± 14.72 km3 for these extrapolated lakes, indicating an estimate of 1357.67 ± 68.94 km3 for the LWSsc of the global natural lakes (>10 km2). This initial estimation of LWSsc at a global scale will greatly help the improvement of our understanding of the seasonal behavior of lakes and reservoirs in regulating global and regional water cycles and the contribution of terrestrial water storage to sea level rise.

The structure of Adonis wolgensis Stev. coenopopulation in the conditions of Northern Kazakhstan

The article presents the study results made on the Adonis wolgensis coenopopulation in Northern Kazakhstan (2018–2019). The materials have been gathered in the course of field research taking into account the literary data. The age structure of the coenopopulations is provided on the basis of detailed route studies. There have been studied eight coenopopulations located in Akmola, Pavlodar, and Kostanay regions. A. wolgensis is a short-stem herbaceous polycarpic of Northern Kazakhstan. A. wolgensis coenopopulations are found in three main habitats: steppe, meadow-steppe, and forest communities. The study of A. wolgensis coenopopulations in the latitudinal direction from Ekibastuz in the east to the Kostanay region in the west has revealed a high recovery index in steppe ecotopes. In other coenopopulations it is less than one. It is especially low in forest habitats. Most coenopopulations have a normal character according to the spectrum of age conditions, and they are maturing. This fact proves no negative impact of environmental and anthropogenic factors on the structure of coenopopulations and ensures their recovery and preservation.

Aspects of the summer circulation in the eastern Ligurian Sea

Water exchanges between the Tyrrhenian Sea and the Liguro-Provençal basin occur through the Corsica Channel, a narrow passage between Corsica and the Elba Island, near the Italian coast. It has long been known that the Channel hosts a robust Tyrrhenian outflow in winter, which penetrates far into the Ligurian Sea, reaching the site where deep-water formation takes place. The summer circulation in the area, and, more generally, in the eastern part of the Ligurian Sea, is less well known. Several experimental and modelling works in the last decade have pointed out the presence of an anticyclone in the Channel area, sometimes referred to as Ligurian anticyclone, which could modulate the exchanges between the two basins in summer, and could strongly affect the dispersion properties in the south-eastern Ligurian Sea, with implications on the local, delicate marine environment. In this work, we focus on this structure, and on the role it plays in the local circulation, seeking information from long datasets of satellite observations (sea level, sea surface temperature and turbidity) that are now available. We find that the Ligurian anticyclone is a recurrent feature of the local circulation in summer. Its core is located between Cap Corse (the peninsula at the northern end of Corsica) and the Elba Island, but the anticyclone may extend till the Italian coast, and it may sometimes be more elongated in the latitudinal direction, and/or more displaced towards north. In some years, a companion anticyclonic vortex is found more to the north, in the north-eastern portion of the Ligurian Sea, but the robustness of this structure is unclear. Analysis of the ERA5 winds indicates that the Ligurian anticyclone is likely driven by an area of negative wind stress curl usually present near Cap Corse in summer, even though contributions from the surrounding circulation cannot be a priori excluded.

Climate Comfort Evaluation of National 5A TouristAttractions in the Mainland of China Based on Universal Thermal Climate Index

Based on the daily climate data from 839 meteorological stations covering the 2014–2017 period in the mainland of China, the Universal Thermal Climate Indices (UTCI) were calculated and the UTCI of 247 national 5A tourist attractions in the mainland of China are obtained with ordinary kriging interpolation method. Then, a spatial analysis of all the attractions was carried out based on UTCI. The results showed that the mainland of China’s annual average UTCI is generally distributed as strip-belts along a latitudinal direction and the climate comfort level gradually decreases from south to north. Significant regional differences in climate comfort results are obtained between the southeast coastal areas and the northwest inland. It was found that the number of attractions with the best climate comfort level is relatively high in spring and autumn while it is less in summer and winter. Considering the climate comfort levels, the attractions are grouped into five categories of “comfortable during spring and autumn,” “comfortable during winter,” “comfortable during spring, autumn, and winter,” “comfortable during spring, summer, and autumn,” and “uncomfortable during the four seasons” to carry out the study for determining the most convenient period of the year in terms of climate comfort.

Solution of the linear and nonlinear advection–diffusion problems on a sphere

AbstractVarious linear advection–diffusion problems and nonlinear diffusion problems on a sphere are considered and solved using the direct, implicit and unconditionally stable finite‐volume method of second‐order approximation in space and time. In the absence of external forcing and dissipation, the method preserves the total mass of the substance and the norm of the solution. The component wise operator splitting allows us to develop the direct (noniterative) and fast numerical algorithm. The split problems in the longitudinal direction are solved using the Sherman‐Morrison formula and Thomas algorithm. The direct solution of the split problems in the latitudinal direction requires the use of the bordering method for a block matrix, and the preliminary determination of the solution at the poles. The resulting systems with tridiagonal matrices are solved by the Thomas algorithm. The numerical experiments demonstrate that the method correctly describes the local advection–diffusion processes on the sphere, in particular, through the poles, and accurately simulate blow‐up regimes (unlimited growing solutions) of nonlinear combustion, the propagation of nonlinear temperature and spiral waves, and solutions to Gray‐Scott reaction–diffusion model.

Trajectory Tracking of Nonlinear Unmanned Rotorcraft Based on Polytopic Modeling and State Feedback Control

Trajectory tracking is extremely difficult for rotorcrafts based on the nonlinear model and taking into account all the parameters of the system and especially considering the effects of flapping and the main rotor and its control tail in all directions. This paper describes the tracking route, based on nonlinear model and velocity control and feedback mode and Polytopic linear parameter varying (LPV) modeling with the help of solving linear matrix inequalities (LMI) equations for different conditions and complex maneuvers for an unmanned rotorcraft that has been examined in all directions including, longitudinal, altitudinal, latitudinal directions. Based on the different operating points of the system and the different flight conditions, first a Polytopic modeling of the system is performed, and then the control signal is generated based on the state feedback and solution of the linear matrix inequalities (LMI) equations. The final control signal consists of feedback of changes of the state variables around the nominal trajectory under the designed feedback gains, in addition to the nominal control signal for the desired trajectory. In calculating the nominal control signal for the optimum trajectory, the Polytopic system model is used instead of the nonlinear system model. Therefore, the final control signal does not require a dynamic system model and all control calculations are performed using a Polytopic system model and have high computational speed. System simulation shows the capabilities of the proposed control system in different operating conditions.

Quantifying horizontal length scales for surface wind variability in the tropical Pacific based on reanalyses

The characteristic spatial sampling length scales (for example, in the longitudinal direction) to adequately resolve the variability associated with a quantity to be observed, depends on the typical length scales of its variability. For example, if temporal variations in the longitudinal direction are correlated over thousands of Kilometers then an observing network with a similar spatial density may be enough to sample the variability with adequate fidelity. Given the importance of surface wind stress in the equatorial tropical Pacific in determining sub-surface oceanic variability, particularly in relation to the evolution of El Nino—Southern Oscillation (ENSO), in this analysis the horizontal length scales of surface wind stress variability based on two reanalysis products—the Climate Forecast System Reanalysis and the ERA-Interim—are documented. The analysis is of relevance to the future evolution of the Tropical Pacific Observing System. As the current design of the Tropical Atmosphere Ocean [that has a wider (narrower) separation in the longitudinal (latitudinal) direction] was originally envisioned following estimates of the length scales of wind variability based on the observational record from tropical Pacific Islands (Harrison and Luther in J Clim 3:251–271, 1990), we find a similar characteristics for length scales for the surface wind variability based on reanalyses datasets. Further, the inferences based on two reanalysis products have a large degree of similarity, and thereby, give us some confidence in the reanalysis products for the purposes of analyzing the length scales of surface wind stress variability, and further, providing some basic information about the requirements for a sustained observing system in the tropical Pacific to monitor and to predict ENSO.

Throat aurora observed by DMSP/SSUSI in a global view

Throat aurora was defined based on the ground observations near local noon and has been suggested to be the ground signature of an indentation on the subsolar magnetopause. A global view of the auroral oval with throat aurora will be critical for inferring global processes at the magnetopause, but it has never been achieved. Using imaging spectrograph observations from Defense Meteorological Satellite Program satellites, for the first time, here we show typical throat auroras in a global view and reveal some important observational facts as follows. (1) The throat auroras can be as long as ~8 degrees in latitudinal direction, which is hardly to be fully seen in the ground-based camera. (2) The plasma flows and field aligned currents associated with throat aurora show consistences with previous radar observations, which have been suggested to be the observational evidence of magnetopause reconnection. (3) Most importantly, we confirmed that the electron and ion precipitations associated with throat aurora are always spatially separated, i.e., electrons in the east and ions in the west. The observational results not only establish a new picture of the aurora oval near local noon, but also provide important support to a conceptual model of throat aurora.

Rapid analysis of a doxycycline hydrochloride solution by metallic mesh device-based reflection terahertz spectroscopy.

Terahertz (THz) spectroscopy has the advantages of non-ionization and spectroscopic fingerprint, which can be used for biological and chemical compound analysis. However, because of the strong absorption of water in the THz region, it is still a challenge for THz waves to realize aqueous solution detection. In this study, taking a doxycycline hydrochloride (DCH) aqueous solution as the target, we proposed a THz metallic mesh device (MMD) based reflection platform for the first time for sensing. The angle characteristics of the THz MMD was investigated through numerical simulations and experimental measurements to get an optimized configuration for the platform. When the projection of THz electric field polarization onto the MMD plane gets parallel to latitudinal direction of the MMD apertures, a strong resonant surface mode can be achieved, and our proposed platform can be successfully used to detect the DCH solution with a concentration as low as 1 mg L-1. The sensing mechanism of our platform was also explored by analyzing the influences of the immersion depth into the MMD holes and the extinction coefficient of droplets on the reflection spectra. Our work presents a rapid, low-cost, and practical platform for antibiotic solution sensing using THz radiation, which opens new avenues for the microanalysis of chemicals or biomolecules in strongly absorptive solutions in the THz region.

Frequency analysis of a graphene platelet–reinforced imperfect cylindrical panel covered with piezoelectric sensor and actuator

The main point of the current study is that the frequency analysis of a graphene platelets–reinforced composite (GPLRC) imperfect panel covered with piezoelectric sensor and actuator (PISA) based on the 3D elasticity theory is investigated. Rule of mixture is employed to obtain varying mass density and Poisson’s ratio, while module of elasticity is computed by modified Halpin-Tsai model. The governing equations are obtained using the 3D elasticity theory. By using Fourier series expansion along the longitudinal and latitudinal directions for the stress and displacement fields, a closed form solution is derived. The novelty of the current study is the consideration of the GPLRC panel and PISA, as well as imperfection are implemented on the proposed model using theory of 3D elasticity. Due to perfect bonding between piezoelectric layers and core the compatibility conditions are derived. Finally, influences of PISA thickness, graphene platelet (GPL) distribution pattern, porosity, span angle of panel, number of layers and GPL weight function on the dynamic stability of the GPLRC smart imperfect panel are presented. Another important consequence is that the sandwich panels with lower span angle have better natural frequency. In other words, to obtain desirable frequency response using structures which their shape is similar to GPLRC plate is more recommended than those resemble to GPLRC cylindrical shell.

Spreading to north: naturalisation of Ficus carica (Moraceae) in Hungary

Between the years 2015–2018, 147 stands of Ficus carica L. was found out of cultivation in Baranya county. In 2008 presence of fig wasp (Blastophaga psenes L.) and caprificus individuals that are necessary for pollination, then for producing fertile seeds were detected in Pécs at first time. For germination tests fig seeds were collected from several different stands in Pécs and successful reproduction of the species was confirmed under in vitro conditions. According to former and recent observations (i.e. subspontaneous seedlings and/or successful in vitro germination of common fig seeds in 2010 and 2014) fig wasp may have occurred in Budapest and Máriagyűd too, at least in the last ten years. These results confirm that F. carica is an old ‘new’ casual or may be a naturalised neophyte element of the Hungarian flora. According to the new records the northernmost escaped individuals of F. carica was found at 47.475° N in the Carpathian Basin, 116.5 km N of the closest Slovenian stand in the latitudinal direction.

Christian mission in Northern Black Sea region and its geopolitical significance

The spread of Christianity in the Northern Black Sea Region was a continuation of the vector of cultural expansion into this region, outlined in Antiquity and opposing the region’s stable geopolitical ties in the latitudinal direction, with the steppe world of the nomads of Eurasia. The stages of this process were: the Great Greek colonization on Pontus Euxinus; the spread of Pax Romana to the territory of Crimea; the Christianization of the region and the strengthening of Byzantium in the Northern Black Sea Region through an alliance with the Khazaria and the creation of the Klimata-Cherson thema; finally, the emergence of Italian trading posts and the emergence of Genoese Gazaria. The success of the Christian mission of Byzantium would not have been possible without the oncoming movement from the north, which determined the reception of the Byzantine civilization by Rus’-Russia and predefined the geopolitical contours of the modern world. In the opposite direction there was an advance to the south of Rus’ and the formation of the path “from the Varangians to the Greeks”, sea voyages of the Rus’ princes to Constantinople, the capture of Korsun’Cherson by Vladimir the Saint and the baptism of Rus’, the inclusion of Russia in the system of the Byzantine church administration. At the new historical stage, after the fall of Byzantium, the role of the Christian Orthodox empire passed to Russia, and the processes of intercivilizational interaction in the region changed their vector. But even in the new conditions, the meridional dimension remains incomparably more important than the latitudinal dimension: a fact that determines the future geopolitical perspective.

Тяжелые металлы в почвах геохимически сопряженных ландшафтов Красноуральского промышленного узла

The results of a study of the gross content of heavy metals in soils in the area of operation of the Svyatogor copper smelter located in the Sverdlovsk region are presented. In the course of the research, sections were laid at different distances and directions from the emission source. The gross concentration of Zn, Cd, Pb, and Cu was measured in the selected soil samples. According to the results of the analysis, a ranking was carried out with the calculations of the total pollution coefficient, lateral and radial differentiation of heavy metals, and the technogenicity index. In order to confirm the routes of the arrival of heavy metals with airport emissions, the maximum single surface concentration in atmospheric air was calculated with the calculation of the distance at which this concentration reaches its maximum value. In the calculation of the total pollution coefficient, it follows that areas located in the immediate vicinity of the emission source have an extremely dangerous category of soil pollution. Also, in these areas, the proportion of technogenic involvement of the element is more than 90%. The obtained values of the coefficient of radial differentiation of heavy metals in the meridional and latitudinal directions, indicates the presence of a number of physical and chemical geochemical geochemical barriers. The migration of heavy metals between conjugated systems is confirmed by the lateral differentiation coefficients. In the course of the work, the main sources of heavy metals entering the soil were identified, such aero-industrial emissions of the plant and aeolian transfer from technogenic disturbed lands. Among the identified patterns of distribution of heavy metals, the main ones are the presence of a high degree of relations of disturbed lands with autonomous natural areas and periodic changes in the direction and power of aero-technogenic flows of the plant.

Features of the formation of the St. Petersburg agglomeration by the beginning of the XX century

The study of the Russian historical St. Petersburg agglomeration at all stages from its foundation (from 1703) until the final imperial stage (1917) required the use of complex functional, urban-planning and landscape, socio-economic, environmental, transport and communication analysis on the basis of data from archives, historical cartography and iconography. The main results were the conclusions that during the XVIII - early XX centuries, there was a crystallization of a huge agglomeration around the city of St. Petersburg, which included three belts: “external”, “middle”, “nearby”, which spatially extended from Yaroslavl (in Central Russia) to Riga (in the Baltic). The paper discusses the features of the formation of the “nearby belt” of agglomeration in the initial (1703 - January 1725) and in the final (1901-1916) development periods. The study revealed a significant role of special types of objects in these processes - estates of the aristocratic society and “garden cities” that provided a belt (around St. Petersburg and the largest settlements and complexes), linear (along radial and ring highways), and nodal (around individual large settlements) construction, spreading in the latitudinal direction from Narva and Ivangorod to the mouth of the Syas river, and in the meridian direction - from Vyborg to the city of Luga. Within the boundaries of this agglomeration zone, four sub-agglomerations had begun to emerge since the 1710s and have fully formed by the 1910s. The materials of the paper can be useful both for historians of urban planning and for modern urbanists.