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Topic Review
Changing Food Consumption Patterns and Land Requirements
The food consumed and the household size determine the land requirement for food. Continued population growth without improved living standards and adequate food production output per hectare will further exacerbate food insecurity and land shortage in Nigeria.
  • 729
  • 19 Jan 2022
Topic Review
Chemical, Biological, Radiological, and Nuclear Agents
Combating chemical, biological, radiological, and nuclear (CBRN) threats with novel solutions reduces disasters and accident risks and, at the same time, aids sustainability.
  • 520
  • 16 Feb 2023
Topic Review
Chemtrail Conspiracy Theory
The chemtrail conspiracy theory posits the erroneous belief that long-lasting condensation trails are "chemtrails" consisting of chemical or biological agents left in the sky by high-flying aircraft, sprayed for nefarious purposes undisclosed to the general public. Believers in this conspiracy theory say that while normal contrails dissipate relatively quickly, contrails that linger must contain additional substances. Those who subscribe to the theory speculate that the purpose of the chemical release may be solar radiation management, weather modification, psychological manipulation, human population control, biological or chemical warfare, or testing of biological or chemical agents on a population, and that the trails are causing respiratory illnesses and other health problems. The claim has been dismissed by the scientific community. There is no evidence that purported chemtrails differ from normal water-based contrails routinely left by high-flying aircraft under certain atmospheric conditions. Although proponents have tried to prove that chemical spraying occurs, their analyses have been flawed or based on misconceptions. Because of the persistence of the conspiracy theory and questions about government involvement, scientists and government agencies around the world have repeatedly explained that the supposed chemtrails are in fact normal contrails. The term chemtrail is a portmanteau of the words chemical and trail, just as contrail is a portmanteau of condensation and trail.
  • 20.8K
  • 31 Oct 2022
Topic Review
Chubut Province
Chubut (Spanish: Provincia del Chubut, IPA: [tʃuˈβut]; Welsh: Talaith Chubut) is a province in southern Argentina , situated between the 42nd parallel south (the border with Río Negro Province), the 46th parallel south (bordering Santa Cruz Province), the Andes range to the west, and the Atlantic ocean to the east. The province's name derives from the Tehuelche word chupat, meaning "transparent," their description of the Chubut River. The largest city is Comodoro Rivadavia in the south of the province; it has 180,000 inhabitants. The administrative capital is Rawson (40,000). Other important cities are Puerto Madryn, Trelew, Esquel and Sarmiento. Gaiman is a cultural and demographic centre of the region known as "Y Wladfa" in which Welsh-Argentines are concentrated. Of the 25,000 Welsh speakers in Argentina, 5,000 live in the Chubut region, particularly in the early Welsh settlements of Gaiman, Trelew and Trevelin.
  • 886
  • 15 Nov 2022
Topic Review
Ciolo (Apulia)
Ciolo is a narrow coastal inlet and a site of historical and environmental interest, which is located in Apulia, Italy. The location is also known as a geological site and for the presence of numerous sea caves, the largest one being the Grotta del Ciolo. Since October 2006 the Ciolo's area has become part of the Regional Park "Costa Otranto - Santa Maria di Leuca e Bosco di Tricase", created by the Apulia region to protect the eastern coast of Salento, specifically the architectural assets as well as important animal and plant species. The name Ciolo comes from the noun in salentino dialect "ciole", which refers to crows or magpies, which are widespread in this region.
  • 1.0K
  • 14 Nov 2022
Topic Review
Classical Plant Breeding
Classical plant breeding uses deliberate interbreeding (crossing) of closely or distantly related species to produce new crops with desirable properties. Plants are crossed to introduce traits/genes from a particular variety into a new genetic background. For example, a mildew resistant pea may be crossed with a high-yielding but susceptible pea, the goal of the cross being to introduce mildew resistance without losing the high-yield characteristics. Progeny from the cross would then be crossed with the high-yielding parent to ensure that the progeny were most like the high-yielding parent, (backcrossing), the progeny from that cross would be tested for yield and mildew resistance and high-yielding resistant plants would be further developed. Plants may also be crossed with themselves to produce inbred varieties for breeding. Germplasm resources from genebanks have invaluable for classical breeding. Classical breeding relies heavily on the naturally occuring plant life-cycle and homologous recombination to generate genetic diversity and to eliminate undesirable traits. It may also makes use of a variety of artificial laboratory procedures to overcome obstacles to introduction of useful traits from wild species that do not usually exchange genes with the domesticated line. These approaches include in vitro techniques such as protoplast fusion, embryo rescue or mutagenisis (see below) to generate genetic alterations and produce transgenic plants that would not exist in nature. Traits that breeders' have tried to incorporate into crop plants in the last 100 years include: Intraspecific hybridization within a plant species was demonstrated by Charles Darwin and Gregor Mendel, and was further developed by geneticists and plant breeders. In the early 20th century, plant breeders realized that Mendel's findings on the non-random nature of inheritance could be applied to seedling populations produced through deliberate pollinations to predict the frequencies of different types. In 1908, George Harrison Shull described heterosis, also known as hybrid vigor. Heterosis describes the tendency of the progeny of a specific cross to outperform both parents. The detection of the usefulness of heterosis for plant breeding has lead to the development of inbred lines that reveal a heterotic yield advantage when they are crossed. Maize was the first species where heterosis was widely used to produce hybrids. Heterosis made breeders aware of the broad practical value of many genes carried in plant chromosomes even when the identity and trait specified by the paticular genes is unknown - that is that diverse plant Germplasm is generally valuable to the breeder. By the 1920s, statistical methods were developed to analyze gene action and distinguish heritable variation from variation caused by environment. In 1933, another important breeding technique, cytoplasmic male sterility (CMS), developed in maize, was described by Marcus Morton Rhoades. CMS is a maternally inherited trait that makes the plant produce sterile pollen, enabling the production of hybrids and removing the need for detasseling maize plants. The scientific use of Transgenic plants in farming gained impetus in the 1930s when a transgenic wheat variety named Hope bred by E. S. McFadden with a transgene originating in a wild grass saved American wheat growers from devastating stem rust outbreaks. These early breeding techniques resulted in large yield increase in the United States in the early 20th century. Similar yield increases were not produced elsewhere until after World War II, the Green Revolution increased crop production in the developing world in the 1960s. Success stories like Hope and hybrid-vigor made it clear that genetic divesity present in wild-species was of great potential value to plant breeders, and eventially lead to the establisment of Germplasm collections consisting of seed-banks devoted to preservation of potentially useful uncharacterised traits for posterity. Following World War II a number of techniques were developed that allowed plant breeders to hybridize distantly related species, and artificially induce genetic diversity. When distantly related species are crossed, plant breeders make use of a number of plant tissue culture techniques to produce progeny from other wise fruitless mating. Interspecific and intergeneric hybrids are produced from a cross of related species or genera that do not normally sexually reproduce with each other. These crosses are referred to as Wide crosses. The cereal triticale is a wheat and rye hybrid. The first generation created from the cross was sterile, so the cell division inhibitor colchicine was used to double the number of chromosomes in the cell. Cells with an uneven number of chromosomes are sterile. Failure to produce a hybrid may be due to pre- or post-fertilization incompatibility. If fertilization is possible between two species or genera, the hybrid embryo may abort before maturation. If this does occur the embryo resulting from an interspecific or intergeneric cross can sometimes be rescued and cultured to produce a whole plant. Such a method is referred to as Embryo Rescue. This technique has been used to produce new rice for Africa, an interspecific cross of Asian rice (Oryza sativa) and African rice (Oryza glaberrima). Hybrids may also be produced by a technique called protoplast fusion. In this case protoplasts are fused, usually in an electric field. Viable recombinants can be regenerated in culture. Chemical mutagens like EMS and DMSO, radiation and transposons are used to generate mutants with desirable traits to be bred with other cultivars. Classical plant breeders also generate genetic diversity within a species by exploiting a process called somaclonal variation, which occurs in plants produced from tissue culture, particularly plants derived from callus. Induced polyploidy, and the addition or removal of chromosomes using a technique called chromosome engineering also found uses. When a desirable trait has been bred into a species, a number of crosses to the favoured parent are made to make the new plant as similar as the parent as possible. Returning to the example of the mildew resistant pea being crossed with a high-yielding but susceptible pea, to make the mildew resistant progeny of the cross most like the high-yielding parent, the progeny will be crossed back to that parent for several generations (See backcrossing ). This process removes most of the genetic contribution of the mildew resistant parent. Classical breeding is therefore a cyclical process. It should be noted that with classical breeding techniques, the breeder does not know exactly what genes have been introduced to the new cultivars. Some scientists therefore argue that plants produced by classical breeding methods should undergo the same safety testing regime as genetically modified plants. There have been instances where plants bred using classical techniques have been unsuitable for human consumption, for example the poison solanine was accidentally re-introduced into varieties of potato through plant breeding.
  • 1.9K
  • 14 Oct 2022
Topic Review
Climate Change Adaptation in Greenland
Climate change adaptation is a pressing issue in Greenland. The term climate change describes long-term changes to the climate system. Since the 1950s a stark rise in global temperatures has been observed. As climate change, whether natural or anthropogenic, impacts the livelihoods of people across the globe, responses i.e. ways to prepare and adjust under changing vulnerabilities become important. Such responses are commonly discussed under the term adaptation, "the process of adjustment to actual or expected climate and its effects", as defined by the IPCC. Geographically Greenland is situated between the Arctic and the Atlantic Ocean, with one third of the island being north of the Arctic Circle. Since the middle of the 20th century, the Arctic has been warming at about twice the global rate. Rising temperatures put increasing pressure on certain plant and tree species and contribute to Greenland's melting ice sheet. This affects and changes the livelihood of the Greenlandic population, particularly the Inuit people, which make up to 80 percent of the total population. Besides the decline of fish stocks, the country's landscape is changing: the melting ice reveals minerals, oil and gas. This has attracted interest from local and foreign investors for potential resource extraction. As new industries are accompanied by new job opportunities and potential wealth, lifestyles are changing. Greenland is in transition, in terms of biophysical as well as cultural and social conditions.
  • 2.6K
  • 20 Nov 2022
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
Climate Change, Security and the Nexus Concept
The nexus concept has been emerging since the Bonn 2011 Conference, “The Water Energy and Food Security Nexus—Solutions for the Green Economy”, with significant involvement from the UN and other international organisations. It has been defined as a “set of context-specific critical interlinkages between two or more natural resources used in delivery chains towards systems of provision”. From a policy perspective, it looks at delivery chains of resources, such as water and energy, in a polycentric manner, i.e., as independent providers based on ecosystem services with interlinkages across delivery stages, but without a presumed hierarchy among those dimensions. Thus, water, energy and food are seen as interrelated and of equal priority for the SDGs, considering the specific conditions of their provision and the strategic interests of relevant actors.
  • 803
  • 15 Oct 2021
Topic Review
Coastal Assessment and MAM of Sea Level Rise
Sea level rise (SLR) is one of the most pressing challenges of climate change and has drawn noticeable research interest. Factors induced by global climate change, such as temperature increase, have resulted in both direct and indirect changes in sea levels at different spatial scales. Various climatic and non-climatic events contribute to sea level changes, posing risks to coastal and low-lying areas. Nevertheless, changes in sea level are not uniformly distributed globally due to several regional factors such as wave actions, storm surge frequencies, and tectonic land movement. The high exposure to those factors increases the vulnerability of subjected areas to SLR impacts. The impacts of events induced by climate change and SLR are reflected in biophysical, socioeconomic, and environmental aspects. Different indicator-based and model-based approaches are used to assess coastal areas’ vulnerabilities, response to impacts, and implementation of adaptation and mitigation measures. Various studies have been conducted to project future SLR impacts and evaluate implemented protection and adaptation approaches, aiding policymakers in planning effective adaptation and mitigation measures to reduce damage.
  • 218
  • 07 Mar 2024
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