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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

The socio-economic contributions of large-scale plantation forests: perceptions of adjacent rural communities in the Northern Province of Sierra Leone

Kainyande, Aruna, Auch, Eckhard F., Okoni-Williams, Arnold D. 31 May 2024 (has links)
The rapid demand for wood products globally has put pressure on natural forests. Therefore, global efforts are now being directed toward establishing plantation forests to fill the wood supply gap while reducing the pressure on natural forests. This study conceptualized the socio-economic contribution of large-scale plantation forests to adjacent rural communities in the Northern Province of Sierra Leone based on the local perceptions of 125 households interviewed during data collection. To complement the household survey data, two forest-plantation experts were interviewed. The study found that local communities mainly benefit from plantation forestry through employment, improved road conditions, and water well constructions. However, the delivery of these benefits differed among the communities depending on the spatial distance from the plantation forestry central office. Benefits related to improvements in road conditions were perceived higher in the more far away communities. The trend is similar for the perception of benefits from plantation forestry activities: the farthest community with limited opportunities for alternative livelihood options appreciated the plantation forestry benefits highly and as fairly distributed. The results further revealed that perceived benefits from the plantation forestry industry, specifically employment and income, were rather unevenly distributed because the elites were able to capture more benefits than the others. These people were also identified to be influential in the distribution of benefits from the plantation industry. It is suggested that the plantation industry makes a conscious effort to extend the delivery of benefits to more community members regardless of their landholding, social status, or education level to ensure equal access to employment and land lease income, as well as CSR benefits.
2

Two-dimensional conjugated metal–organic frameworks (2D c-MOFs): chemistry and function for MOFtronics

Wang, Mingchao, Dong, Renhao, Feng, Xinliang 17 May 2024 (has links)
The 21st century has seen a reinvention of how modern electronics impact our daily lives; silicon-electronics and organic electronics are currently at the core of modern electronics. Recent advances have demonstrated that conductive metal–organic frameworks (MOFs), as another unique class of electronic materials, are emerging to provide additional possibility for multifunctional electronic devices that brings us “MOFtronics”. Typically, two-dimensional conjugated MOFs (2D c-MOFs) are a novel class of layer-stacked MOFs with in-plane extended π-conjugation that exhibit unique properties such as intrinsic porosity, crystallinity, stability, and electrical conductivity as well as tailorable band gaps. Benefiting from their unique features and high conductivity, 2D c-MOFs have displayed great potential for multiple high-performance (opto)electronic, magnetic, and energy devices. In this review article, we introduce the chemical and synthetic methodologies of 2D c-MOFs, intrinsic influences on their electronic structures and charge transport properties, as well as multifunctional applications of this class of materials for MOFtronics and potential power sources for MOFtronics. We highlight the benefits and limitations of thus-far developed 2D c-MOFs from synthesis to function and offer our perspectives in regard to the challenges to be addressed.
3

Correction: Two-dimensional conjugated metal–organic frameworks (2D c-MOFs): chemistry and function for MOFtronics

Wang, Mingchao, Dong, Renhao, Feng, Xinliang 17 May 2024 (has links)
Correction for ‘Two-dimensional conjugated metal–organic frameworks (2D c-MOFs): chemistry and function for MOFtronics’ by Mingchao Wang et al., Chem. Soc. Rev., 2021, 50, 2764–2793, DOI: 10.1039/D0CS01160F.
4

Performance Effects of Multinationality

Ral-Trebacz, Arkadiusz 20 February 2017 (has links) (PDF)
The performance effects of multinationality have been subject to extensive study over the last four decades. To date, the findings of empirical studies have not been able to demonstrate a consistent picture as far as the relationship between multinationality (M) and performance (P) is concerned; nor have they established a general link. This dissertation suggests that the M-P relation might be contingent upon certain contextual considerations. In particular, this doctoral thesis examines the performance effects of multinationality depending on a) scope of international expansion (regional vs. global); b) the role of firm-specific assets (FSAs) and c) home region effects.
5

Performance Effects of Multinationality: The Role of Firm-specific Advantages, Intra- and Inter-regional Expansion, and Home-region Effects

Ral-Trebacz, Arkadiusz 06 February 2017 (has links)
The performance effects of multinationality have been subject to extensive study over the last four decades. To date, the findings of empirical studies have not been able to demonstrate a consistent picture as far as the relationship between multinationality (M) and performance (P) is concerned; nor have they established a general link. This dissertation suggests that the M-P relation might be contingent upon certain contextual considerations. In particular, this doctoral thesis examines the performance effects of multinationality depending on a) scope of international expansion (regional vs. global); b) the role of firm-specific assets (FSAs) and c) home region effects.
6

Reproductive behaviour of the European Common Frog (Rana temporaria)

Dittrich, Carolin 26 June 2020 (has links)
In meiner Dissertation untersuche ich das Paarungs- und Fortpflanzungsverhalten des Europäischen Grasfrosches (Rana temporaria) in einem evolutionären Kontext. Mein Ziel ist es zu verstehen, welche Mechanismen zur Bildung von Paaren führen, ob die Partnerwahl die Paarungsmuster erklärt, die wir beobachten können, und ob es evolutive Vorteile gibt, die sich aus der Paarung mit einem bestimmten Partner ergeben. Die Suche nach und die Konkurrenz um Paarungspartner führt zur Entwicklung verschiedener Paarungssysteme, Strategien und Taktiken, um den Reproduktionserfolg während der gesamten Lebensdauer zu erhöhen. Das Paarungsverhalten wird durch natürliche und sexuelle Selektion beeinflusst, wobei beide in unterschiedliche Richtungen wirken können. Für die meisten Individuen ist das Überleben unerlässlich, um sich so oft wie möglich zu reproduzieren, und dadurch die reproduktive Gesamtfitness zu erhöhen. Andererseits könnte ein auffälliges Verhalten bei der Fortpflanzung das Prädationsrisiko erhöhen. Der Akt der Paarung selbst kann bereits mit Risiken verbunden sein, welche sich auf die Überlebensraten auswirken können. Durch sexuelle Selektion könnten bestimmte sekundäre Geschlechtsmerkmale begünstigt werden, entweder aufgrund von Vorteilen im Wettbewerb innerhalb eines Geschlechts (intrasexuell), oder aufgrund spezifischer Präferenzen zwischen den Geschlechtern (intersexuelle Selektion). Damit sich die Partnerwahl entwickeln kann, muss der gewählte Paarungspartner Vorteile aufweisen, von denen der wählende Partner profitiert, denn die Wahl ist mit energetischen Kosten und zeitlichem Aufwand verbunden. Als Frühlaicher muss der Europäische Grasfrosch mit einem eingeschränktem Paarungszeitraum umgehen. Die Männchen konkurrieren um den Zugang zu Weibchen und es wird angenommen, dass sich Weibchen während der Paarung und Reproduktion passiv verhalten, da der hohe "Männchen-Überschuss" keine Wahl zulassen würde. Aus evolutionärer Sicht sollten Weibchen jedoch das wählerische Geschlecht sein und entscheiden mit wem sie sich paaren, da sie mehr Energie in die Eierproduktion investieren. / In my thesis, I examine the mating and reproductive behaviour of the European Common Frog (Rana temporaria) in an evolutionary context. I aim to understand which mechanisms lead to the formation of pairs, if mate choice shapes the patterns of mating that we can observe and if there are benefits derived from pairing with a specific mate. The search and competition for mating partners lead to the evolution of various mating systems, strategies and tactics to increase lifetime reproductive success. The mating behaviour is influenced by natural and sexual selection, whereby both could act in different directions. For most individuals, survival is essential in order to reproduce as often as possible to increase lifetime reproductive fitness. On the other hand, reproduction could increase predation risk due to conspicuous behaviour and risks associated with mating itself. Sexual selection could favour specific secondary sexual traits, either due to advantages in intrasexual competition, or by specific preferences of the choosy sex (intersexual selection). For mate choice to evolve, there need to be benefits associated with the chosen mating partner, because choosiness involves costs in terms of energy and time constraints during mating. As an explosive breeder, the European Common Frog has to deal with time constraints during the short breeding season. The males are competing for the access to females and it is assumed that females are passive during breeding due to a high male-biased operational sex ratio. However, from an evolutionary perspective females should be the choosy sex and should decide with whom to mate, as they invest more energy into the production of eggs.
7

Economic and environmental effects of Integrated Pest Management program: A case study of Hau Giang province (Mekong Delta)

Nguyen, Trung Dung 16 January 2019 (has links)
Since many years, the agro-technical programs such as '3 reduction 3 increase', '1 must 5 reduction' and System of Rice Intensification (SRI) have been carried out with definite results. Recently, IPM program (integrated pest management) – a more comprehensive measure (using all possible techniques and methods to keep the pest populations below a level causing economic injury) – has been firstly piloted on a large scale in the Mekong Delta. This paper presents the main results of piloting IPM program in 2,610 hectares during 2014-2017 in Hau Giang province. As results, farmers have better economic benefit in production; the quality of rice has been gradually improved and can overcome the technical barriers of advanced countries in rice trade such as US, EU and Japan. In addition, the environmental and ecological consequences can be avoided due to overuse of fertilizer and pesticide. Field ecosystems will be gradually restored. / Từ nhiều năm nay những chương trình kỹ thuật nông nghiệp như '3 giảm 3 tăng', '1 phải 5 giảm' và hệ thống canh tác lúa cải tiến (SRI) đã được áp dụng và đã có những kết quả nhất định. Còn chương trình quản lý dịch hại tổng hợp IPM - một biện pháp tổng hợp và tích cực hơn (sử dụng tất cả các kỹ thuật và biện pháp thích hợp có thể được, nhằm duy trì mật độ của các loài gây hại dưới mức gây ra những thiệt hại kinh tế) – được thực nghiệm đầu tiên trên diện rộng ở Đồng bằng sông Cửu Long. Bài báo này trình bày những kết quả chính trong thử nghiệm ở 2.610 ha lúa trong thời gian 2014-2017 ở ở tỉnh Hậu giang. Kết quả là quản lý dịch hại ở ngưỡng cho phép, người nông dân có lợi hơn về kinh tế trong sản xuất, chất lượng gạo từng bước được cải thiện và có khả năng vượt qua các hàng rào kỹ thuật trong thương mại lúa gạo của các nước tiên tiến như USA, châu Âu, Nhật Bản. Ngoài ra tránh được hệ quả về môi trường sinh thái do sử dụng quá mức phân bón hóa học và ô nhiễm do thuốc bảo vệ thực vật và hệ sinh thái đồng ruộng dần được phục hồi.

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