Topic Review
Urban Ecosystem Models
Urban ecosystem services provide many benefits for human beings. Given the dramatic increase of urbanization, maintaining sustainability of cities relies heavily on ecosystem services, and it is crucial for quantifying, managing, and optimizing urban ecosystem services to promote social and ecological sustainable development. 
  • 800
  • 22 Apr 2022
Topic Review
Urban Built and Mixed Spaces
Natural areas are now broadly recognised as important resources to restore the cognitive and emotional resources of urban dwellers, but everyday urban environments are rarely studied for their salutogenic properties. This review collects emerging evidence of instances in which built and mixed urban environments were found to be more restorative than natural ones for the urban population. Generally, historical, recreational and panoramic places have been found to have the most restorative potential of all mixed and built urban environments. This particularly applies to teenagers and older people who value social interactions for their well-being. Vegetation and natural elements were still found to play an important role in the assessment of this restorative potential.
  • 803
  • 27 Oct 2020
Topic Review
Uranium Mineralization of Fossil Wood
Sandstone-hosted uranium deposits commonly contain abundant organic matter, including fossil logs. The precipitation of uranium minerals is often related to reducing environments associated with these organic materials. Below the water table, uranium is likely to be precipitated as uraninite (UO2), but in drier zones a variety of uranium minerals may be found. These minerals may occur as replacements for cellular tissue, or as surface crusts or fracture fillings.
  • 1.8K
  • 28 Oct 2020
Topic Review
Upwelling in Marginal Seas
Upwelling refers to the upward movement of deep nutrient-rich and low-temperature waters to the surface, resulting in colder surface or near-surface waters with low dissolved oxygen, high density, and high salinity. Upwelling is economically and ecologically significant in the coastal marine system, making it high-priority research. Although representing <1% of the total surface area of the ocean, upwelling regions provide approximately 8% of the global marine primary production and more than 20% of the world’s capture fisheries. With an increase in offshore transport, strong upwelling usually transports phytoplankton and zooplankton towards the convergence offshore frontal system rapidly, relative to a weaker upwelling that limits the nutrient enrichment in the photic zone. Apart from boosting primary productivity and fishery production, upwelling is also crucial for the atmosphere-ocean carbon dioxide exchange and carbon recycling processes.
  • 403
  • 04 Aug 2023
Topic Review
Upper Mantle (Earth)
The upper mantle of the Earth begins just beneath the crust about 35 km (22 mi) and ends at the top of the lower mantle at 670 km (420 mi). Temperatures range from approximately 200 °C (392 °F) at the upper boundary with the crust to approximately 900 °C (1,650 °F) at the boundary with the lower mantle. Upper mantle material which has come up onto the surface is made up of about 55% olivine, 35% pyroxene and 5 to 10% of calcium oxide and aluminum oxide minerals such as plagioclase, spinel or garnet, depending upon depth.
  • 5.4K
  • 29 Sep 2022
Topic Review
Unmanned Aerial Vehicles in Forest Health Monitoring
Unmanned aerial vehicles (UAVs) are platforms that have been increasingly used over the last decade to collect data for forest insect pest and disease (FIPD) monitoring. These machines provide flexibility, cost efficiency, and a high temporal and spatial resolution of remotely sensed data. 
  • 544
  • 28 Jul 2022
Topic Review
Unmanned Aerial Vehicles Implementations in Urban Planning
The rapid growth of urban populations and the need for sustainable urban planning and development has made Unmanned Aerial Vehicles (UAVs) a valuable tool for data collection, mapping, and monitoring.
  • 496
  • 12 Jun 2023
Topic Review
Unmanned Aerial Vehicle Remote Sensing
Unmanned aerial vehicle (UAV) remote sensing has been widely used in agriculture, forestry, mining, and other industries. UAVs can be flexibly equipped with various sensors, such as optical, infrared, and LIDAR, and become an essential remote sensing observation platform. Based on UAV remote sensing, researchers can obtain many high-resolution images, with each pixel being a centimeter or millimeter. 
  • 514
  • 30 Jun 2023
Topic Review
Unmanned Aerial Systems in Hydrogeology
In less than two decades, UASs (unmanned aerial systems) have revolutionized the field of hydrology, bridging the gap between traditional satellite observations and ground-based measurements and allowing the limitations of manned aircraft to be overcome. With unparalleled spatial and temporal resolutions and product-tailoring possibilities, UAS are contributing to the acquisition of large volumes of data on water bodies, submerged parameters and their interactions in different hydrological contexts and in inaccessible or hazardous locations. 
  • 961
  • 29 Apr 2021
Topic Review
Unmanned Aerial Robots’ Applications in Agriculture
The most common role of drones in agriculture is to assess and monitor crops. For this, remote sensing is carried out, but this task is not enough when agricultural applications become more widespread. For this, autonomous mobile robots such as drones and other UAVs with technologically different features are designed for various agricultural purposes.
  • 844
  • 26 Jan 2022
  • Page
  • of
  • 270
Video Production Service