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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Life cycles and secondary production of Ephemeroptera, Plecoptera, and Trichoptera (Insecta) under an extreme continental climate (River Kharaa, Mongolia)

Avlyush, Saulyegul 27 February 2014 (has links) (PDF)
Since the 1990s water quality monitoring projects using aquatic insects or macroinvertebrates as bioindication in Mongolia has mostly occurred in rivers drainage to the Arctic Ocean. They have been conducted to identify different anthropogentic stressors and impacts upon these running water ecosystems. However, there are still knowledge gaps and uncertainties concerning the research of these macroinvertebrates, in particular, a life cycle study of representative species are one such section of information missing. The specific aim for the study was to determine their life cycles and secondary production of selected species in the Kharaa River Basin, Mongolia, where these animals are exposed to harsh environment conditions. The main challenges for the research project were selecting the most suitable methods for use in the field sampling campaigns as well as establishing biomonitoring criteria for the target species under the extreme harsh climatic conditions. The research also sorts to address the pre-existing taxonomical identification problems. Consequently, a multi-habitat quantitative sampling method, and emergence traps type ‘Model week’ were selected. Five specific traits were chosen as selection criteria from the literature, where the life cycles of numerous species were investigated under comparable conditions to this study. Based on those five distinct criteria, a total of 18 species from EPT group (Ephemeroptera, Plecoptera, and Trichoptera) were selected for deeper analysis. This thesis provided the first quantitative results on the life cycle, production, growth rate and emergence of aquatic insects from Mongolia, to allow comparisons with studies in other regions using the same methods. However, it still needs more quantitative research of population dynamics for a wider range of species including fecundity, accurate development rates, mortality losses (e.g., due to predation), and food availability across environmental gradients of hydraulic conditions and substrate types. In conclusion, last not least it is essential to obtain knowledge especially about life cycle strategies of macroinvertebrates to identify the indicator-properties of single species and to predict re-colonisation potential of disturbed habitats and to evaluate the efficiency of management measures.
2

Life cycles and secondary production of Ephemeroptera, Plecoptera, and Trichoptera (Insecta) under an extreme continental climate (River Kharaa, Mongolia)

Avlyush, Saulyegul 12 December 2013 (has links)
Since the 1990s water quality monitoring projects using aquatic insects or macroinvertebrates as bioindication in Mongolia has mostly occurred in rivers drainage to the Arctic Ocean. They have been conducted to identify different anthropogentic stressors and impacts upon these running water ecosystems. However, there are still knowledge gaps and uncertainties concerning the research of these macroinvertebrates, in particular, a life cycle study of representative species are one such section of information missing. The specific aim for the study was to determine their life cycles and secondary production of selected species in the Kharaa River Basin, Mongolia, where these animals are exposed to harsh environment conditions. The main challenges for the research project were selecting the most suitable methods for use in the field sampling campaigns as well as establishing biomonitoring criteria for the target species under the extreme harsh climatic conditions. The research also sorts to address the pre-existing taxonomical identification problems. Consequently, a multi-habitat quantitative sampling method, and emergence traps type ‘Model week’ were selected. Five specific traits were chosen as selection criteria from the literature, where the life cycles of numerous species were investigated under comparable conditions to this study. Based on those five distinct criteria, a total of 18 species from EPT group (Ephemeroptera, Plecoptera, and Trichoptera) were selected for deeper analysis. This thesis provided the first quantitative results on the life cycle, production, growth rate and emergence of aquatic insects from Mongolia, to allow comparisons with studies in other regions using the same methods. However, it still needs more quantitative research of population dynamics for a wider range of species including fecundity, accurate development rates, mortality losses (e.g., due to predation), and food availability across environmental gradients of hydraulic conditions and substrate types. In conclusion, last not least it is essential to obtain knowledge especially about life cycle strategies of macroinvertebrates to identify the indicator-properties of single species and to predict re-colonisation potential of disturbed habitats and to evaluate the efficiency of management measures.
3

Kan återvinning ersätta naturresursutvinning? : Fallstudie av aktörers syn inom koppar- och pappersbranschen / Does Recycling Displace the Extraction of Natural Resources? : Case Study of Actors' Perspective within the Copper and Paper Industry

Åkerfeldt, Klara January 2023 (has links)
Det tolfte målet i FN:s Agenda 2030 handlar om hållbar konsumtion och produktion, som bland annat innefattar mål om en hållbar användning av naturresurser. En strategi som blivit allt mer populär för att effektivisera användandet av naturresurser är återvinning. Den främsta miljöfördelen med återvinning vilar på ett antagande om att det faktiskt ersätter behovet av att ta ut nya resurser från naturen. Syftet med detta kandidatexamensarbete är att ge en ökad kunskap om hur olika aktörer inom koppar- och pappersbranschen ser på återvinning och dess möjligheter att ersätta naturresursutvinning. För att undersöka detta har intervjuer hållits med både företag och myndigheter som verkar i eller har kunskap om respektive branscher. Resultatet visar på, enligt de tillfrågade, att en ersättning i dagsläget inte är möjlig. Vad detta beror på verkar dock skilja sig åt mellan de två olika fallen. Resultatet visar att aktörerna inom kopparbranschen menar att efterfrågan på koppar ökar mer än den koppar som finns tillgänglig för återvinning till följd av elektrifieringen. För papper är det dock en annan faktor som styr möjligheten för ersättning enligt de tillfrågade. Enligt de tillfrågade aktörerna krävs en viss inblandning av färskfiber kontinuerligt eftersom styrkan hos pappersfibrerna försämras vid varje återvinningsprocess. Aktörerna nämner att det finns förbättringsåtgärder, dessa syftar dock mer åt att förbättra återvinningen generellt och kanske inte nödvändigtvis bidrar till att öka ersättningen. / Responsible consumption and production is one of the Sustainable Development Goals formulated by the UN in 2015. One of the targets concerns sustainable management and use of natural resources. One strategy that has gained more popularity throughout the years to handle this question is recycling. The prime environmental benefit is based on the assumption that recycling displaces the need to extract natural resources. The purpose of this study is to provide increased knowledge of the actors' perspective on the potential of recycling to displace natural resource extraction in the copper and paper industry. Interviews have been done with both companies and authorities. The results show that a complete displacement is not possible. However, the causes of this seem to differ between the two cases. The respondents of the copper industry mention that the increased demand of the metal which will occur as a consequence of the electrification process makes it difficult for a displacement. For paper, on the other hand, the quality loss the fibers suffer from at every recycling process requires continuous supply of raw fiber. However, the results also show a range of improvements that can be implemented to improve recycling in general, if those as well increase the displacement is not necessarily certain.

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