371 research outputs found

    A Dirty Dilemma: Determinants of Electronic Waste Importation

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    During the 1970s-1980s waste, specifically toxic waste from manufacturing, became a globally traded commodity. By the late 1980s, waste trade became a global political and environmental topic because many believed that developed countries were ‘dumping’ hazardous material on less developed nations despite knowing that less developed countries often lack adequate infrastructure to dispose of waste in an environmentally responsible manner, prompting international regulatory responses. This study focuses on the fastest growing category of traded toxic waste – electronic waste. In 2014, approximately 41.8 million tons of electronic waste was generated globally. During this same period 1.6 million tons were traded in the global economy. Electronic waste is particularly intriguing because of its mix of toxic dangers and high value opportunities. Unlike other hazardous waste, electronic waste is composed of toxic materials such as lead, mercury, cadmium and brominated retardants that can adversely affect human health and the environment and valuable recyclables such as iron, copper, gold, silver, and rare earth metals. Scholars debate whether the domestic political structure, international environmental agreements or economic factor is the primary determinant that induce states to import hazardous waste. The aim of this study is to provide insight to this puzzling question. The study creates a Waste Trade Framework that is a compilation of political, economic and environmental determinants. The framework is then tested using partial least squares-structural equation modeling. The study finds that when developed and developing countries are evaluated jointly, the economic factor has the largest impact on electronic waste import volume. When developed and developing countries are modeled independently, electronic waste import volume in both country types is most influenced by the political economic factor (the interaction of politics and the economy)

    Study of Bryophytic Flora in the Ramsar Wetland of Merja Zerga (North-west of Morocco)

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    The research undertaken in the IBA and Ramsar wetland of Merja Zerga at Moulay Bousselham were interested only in the higher plants. Our study tends then to contribute to enrich the knowledge about the bryophytic flora of this area by filling the gaps in this field. Thus, we carried out a systematic sampling with a stop and a harvest in each encountered bryophyte population. This prospection enabled us to find 26 species of bryophytes including 22 species of mosses belonging to 15 genera and 9 families, and 4 species of liverworts belonging to 3 genera and 3 families. The relative low specificity of this wetland can be explained by the influence of sea spray and the strong anthropic disturbance. A comparison with previous studies allowed us to conclude that 11 species were observed for the first time in the area

    Biotransformation of ß-estradiol isolated from Sonchus eruca

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    The biotransformation of ß-estradiol (1,3,5-estratriene-3,17,ß-diols) by Bacillus subtillus resulted in four metabolites which were (1) 3,5-estratriene-3-ol–17–one, (2) 1,3,5-estratriene-3,16,17-triol, (3) 1,3,5,7- estratetra-ene-3-ol-17-one and (4) 1,3,5,6, estratetra-ene-3-ol-17-one. The structures were elucidated on the basis of spectroscopic techniques. Compound 3 showed good inhibitory activity against lipoxygenase enzyme.Key words: Microbial transformation, ß-estradiol (1,3,5-estratriene-3,17,ß-diols), Bacillus subtillus, Aspergillus niger, lipoxygenase

    Study of the bryological flora at the archaeological site of Chellah, Morocco

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    The Chellah archaeological site in Rabat, listed as a cultural asset since 2012 on UNESCO's World Heritage List, is subject to significant biodeterioration. The aim of this study is to identify the bryophytes that have an important impact on the destruction of the substrate. For this purpose, three prospectionswere carried out in autumn 2014, spring 2015 and winter 2016. The systematic sampling carried out allowed us to identify 20 species of bryophytes belonging to 10 botanical families, of which 4are dominant with 13 species equivalent to 65% of the total. The four families are Pottiaceae, Brachyceciaceae, Funariaceae and Bryaceae; they belong to the class of Muscinae. The liverworts are represented by only 6 species, representing 30% of the total population. Among the 20 species inventoried, 3 are newly observed in the region of Rabat: Entosthodon pulchellus (H. Philib.) Brugués; Dydimodon Fallax Hedw. and Trichostomum crispulum Bruch. When bryophytes settle on substrates, a preliminary soilis initiated to the detriment of the quality of materials and their durability

    Gastrointestinal symptoms in patients with isolated oligodontia and a Wnt gene mutation

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    OBJECTIVE: Since Wnt signaling plays an important role in both tooth agenesis and altered intestine homeostasis, the aim was to compare gastrointestinal symptoms in patients with isolated oligodontia caused by a Wnt pathway gene mutation and controls. METHODS: A case-control study was designed to compare self-reported gastrointestinal symptoms among patients with isolated oligodontia, caused by a Wnt signaling gene mutation, and fully dentate controls. The Gastrointestinal Symptom Rating Scale (GSRS) was used to assess gastrointestinal symptoms. Prevalence and severity of gastrointestinal symptoms among patients and age- and gender-matched controls was evaluated. RESULTS: Twenty patients with isolated oligodontia and a pathogenic variant in the wnt pathway genes WNT10A, LRP6 or PAX9 participated. The prevalence of gastrointestinal symptoms was higher in the oligodontia patients compared to their controls (Χ2 (1) = 87.33, p = .008). Mean GSRS total scores (p = .011) and domain scores for 'abdominal pain' (p = .022), 'reflux' (p = .003) and constipation (p = .030) were higher for these oligodontia patients compared to their controls. CONCLUSION: Gastrointestinal symptoms are more prevalent and more severe in patients with isolated oligodontia and a deficiency in a Wnt pathway related gene, when compared to controls without tooth agenesis
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