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Topic Review
Snowmelt Models
The snowmelt model is a hydrological model that simulates the processes of snow accumulation, melt, and confluence. Since the snowmelt process involves the complex energy transfer and water transfer processes between the atmosphere and snow, between different snow layers, and between snow layers and soil, it is more complicated than the formation process of rainfall runoff. If there is a rainfall event on snow, it is very difficult to simulate the runoff generation process due to the mixture of rain and snow. Snowmelt simulation is the basis for the simulation of snowmelt flood formation processes, and it plays a crucial role in accurately modelling snowmelt floods.
  • 1.1K
  • 29 Oct 2021
Topic Review
Multispectral Image
Multispectral imaging captures image data within specific wavelength ranges across the electromagnetic spectrum. The wavelengths may be separated by filters or detected with the use of instruments that are sensitive to particular wavelengths, including light from frequencies beyond the visible light range, i.e. infrared and ultra-violet. Spectral imaging can allow extraction of additional information the human eye fails to capture with its visible receptors for red, green and blue. It was originally developed for military target identification and reconnaissance. Early space-based imaging platforms incorporated multispectral imaging technology to map details of the Earth related to coastal boundaries, vegetation, and landforms. Multispectral imaging has also found use in document and painting analysis. Multispectral imaging measures light in a small number (typically 3 to 15) of spectral bands. Hyperspectral imaging is a special case of spectral imaging where often hundreds of contiguous spectral bands are available.
  • 1.1K
  • 21 Oct 2022
Topic Review
Dryland Food Security in Ethiopia
Global drylands are expanding due to climate change, threatening global food security (FS), especially in Africa. Eastern Africa has 328 million hectares of drylands, 6% of which is covered by crops; most crops are rained on, and irrigated land accounts for only 5 million hectares (22%). In Ethiopia, 75% of the landmass is categorized as dryland, the majority of which experiences high risks of land degradation, natural hazards, and water and food shortages.
  • 1.1K
  • 28 Jun 2021
Topic Review
Mechanisms and Impact of Biofilms
Biofilms comprising aggregates of microorganisms or multicellular communities have been a major issue as they cause resistance against antimicrobial agents and biofouling. To date, numerous biofilm-forming microorganisms have been identified, which have been shown to result in major effects including biofouling and biofilm-related infections. Quorum sensing (which describes the cell communication within biofilms) plays a vital role in the regulation of biofilm formation and its virulence. As such, elucidating the various mechanisms responsible for biofilm resistance (including quorum sensing) will assist in developing strategies to inhibit and control the formation of biofilms in nature. Employing biological control measures (such as the use of bioactive compounds) in targeting biofilms is of great interest since they naturally possess antimicrobial activity among other favorable attributes and can also possibly act as potent antibiofilm agents.
  • 1.1K
  • 13 Oct 2021
Topic Review
Sand Dam Technology
Sand dam technology filters and protects water from contamination and evaporation with low to no maintenance cost. Sand dams improve the socio-economy of the community and help to cope with drought and climate change. However, success depends on the site selection, design, and construction. The ideal site for a sand dam is at a transition between mountains and plains, with no bend, intermediate slope, and impermeable riverbed in a catchment with a slope greater than 2°. The spillway dimensioning considers the flow velocity, sediment properties, and storage target, and the construction is in multi-stages. Recently, the failure of several sand dams because of incorrect siting, evaporation loss, and one-stage construction were reported. Revision of practitioners’ manuals by considering catchment scale hydrological and hydrogeological characteristics, spillway height, and sediment transport are recommended. Research shows that protected wells have better water quality than open wells and scoop holes. Therefore, the community should avoid open defecation, pit latrines, tethering of animals, and applying pesticides near the sand dam. 
  • 1.1K
  • 01 Jul 2021
Topic Review
Biopollution
Biopollution describes the biological pollution caused by the introduction of non-indigenous species into biogeographic regions where they were not present before. It is considered one of the main threats to environmental health, and it is a factor of disturbance that can be consistently viewed as a pollution agent, albeit of a different nature if compared with physical and chemical factors. Ecosystem deterioration may be induced by the development of massive alien population outbreaks following introduction events. Biopollution assessment procedures have been proposed, adopting criteria already used for xenochemical compounds. Also prevention and mitigation measures to reduce biopollution impact have been developed in a similar way as for chemical pollution.
  • 1.1K
  • 12 May 2021
Topic Review
Sources of Arsenic in the Aquatic Environment
Arsenic is an element that is distributed globally and is abundant in the Earth’s crust (20th most abundant element) and seawater (14th most abundant element). It is classified as a metalloid and exhibits both metallic and non-metallic properties. The high solubility and mobility of arsenic in aquatic environments affects its global cycling. Furthermore, the biological processes in the aquatic environment are discussed, especially the possible microbe-mediated reactions of arsenic in sediments. In addition, various environmental factors, such as redox conditions, pH, and salinity, which influence the transformation of arsenic species.
  • 1.1K
  • 04 Jan 2023
Topic Review
Toward a Feminist Agroecology
Agroecology is gaining ground as a movement, science, and set of practices designed to advance a food systems transformation which subverts the patterns of farmer exploitation currently entrenched in dominant agricultural models. A feminist agroecology focuses on redressing unequal gender relations as well as other intersecting relations of marginalization such as race, class, caste, and ethnic identity. 
  • 1.1K
  • 20 Oct 2021
Topic Review
Climate Change and Ecosystems
Climate change has adversely affected both terrestrial and marine ecosystems, and is expected to further affect many ecosystems, including tundra, mangroves, coral reefs, and caves. Increasing global temperature, more frequent occurrence of extreme weather, and rising sea level are among some of the effects of climate change that will have the most significant impact. Some of the possible consequences of these effects include species decline and extinction, behavior change within ecosystems, increased prevalence of invasive species, a shift from forests being carbon sinks to carbon sources, ocean acidification, disruption of the water cycle, and increased occurrence of natural disasters, among others.
  • 1.1K
  • 04 Nov 2022
Topic Review
Genetic Improvement of Wheat for Drought Tolerance
Wheat production and productivity are challenged by recurrent droughts associated with climate change globally. Drought and heat stress resilient cultivars can alleviate yield loss in marginal production agro-ecologies. The ability of some crop genotypes to thrive and yield in drought conditions is attributable to the inherent genetic variation and environmental adaptation, presenting opportunities to develop drought-tolerant varieties. Understanding the underlying genetic, physiological, biochemical, and environmental mechanisms and their interactions is key critical opportunity for drought tolerance improvement.
  • 1.1K
  • 30 May 2022
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