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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.
31

Overcoming marginality on the margins: mapping, logging, and coca in the Amazon borderlands

Salisbury, David Seward 28 August 2008 (has links)
The ecologically and culturally rich Amazonian border zones are increasingly targeted for development and the exploitation of natural resources, even as these zones often double as existing or proposed sites for the conservation of biodiversity and protection of indigenous lands. Governmental and Non-Governmental Organizations alike project their goals from central offices onto borderland landscapes assumed to be empty of local people but full of valuable resources, biodiversity or development potential. Simultaneously, loggers, miners, drug traffickers, and others operate illegally or quasi-legally within these border zones and, in the absence of a strong governmental presence, cultivate the borderland's reputation as a violent hinterland. Within this complex borderland reality, the local people (indigenous and non-indigenous), largely invisible to authorities, struggle to survive with subsistence strategies while either negotiating with illegal interlopers to supplement their income or resisting them for their very survival. The resulting landscape is a tangle of overlapping and competing concessions, conservation units, and indigenous territories whose contestation and resulting confusion advances the agenda of illegal extractivists and drug traffickers. This study highlights the continued importance of fieldwork in geography. Here, field-based research provides insight into the poorly understood borderlands of Peru and Brazil. Research used a combination of participatory methods, Geographic Information Systems, ethnography, document research, and remote sensing to analyze mapping, logging, and coca cultivation within four borderland watersheds. These data were combined with regional data on coca eradication, resource concessions, conservation units, and indigenous territories from both Brazil and Peru. Field-based results demonstrate these borderlands to be highly contested and poorly mapped with an exploitative and poorly managed timber industry and a dynamic front of coca cultivation contributing to social disruption and environmental degradation. More fieldwork is needed to generate the geographic information necessary for sustainable development and conservation planning and to help local people defend their territory from illegal operators and the imposition of state resource concessions. Ecological Economic Zoning is recommended as a participatory policy framework to improve geographic information and long term planning. / text
32

Home gardens, cultivated plant diversity, and exchange of planting material in the Pacaya-Samiria National Reserve area, northeastern Peruvian Amazon

Lerch, Natalie Corinna. January 1999 (has links)
Traditional peoples are often described as "stewards of agricultural diversity", yet little research has been conducted on the determinants of agrodiversity. This thesis focuses on agrodiversity and how peasant farmers build and maintain cultivated plant diversity in home gardens found in three distinct traditional communities along the Maranon river in the Peruvian Amazon---an upland mixed agricultural village, a lowland agricultural village, and a lowland fishing village. Data were gathered through household surveys (n = 192) and in-depth interviews (n = 112). Substantial variation in cultivated plant diversity was found among and within villages. Residents with the highest home garden agrodiversity tend to be among the wealthier households, and are more likely to have both established their own garden, and tended it for longer periods. Complex planting material exchange networks underlie the establishment and maintenance of home garden agrodiversity. The results underscore the importance of studying local variations in agricultural diversity, and exchange networks that bring agricultural planting stock to peasant farmers.
33

Who manages home garden agrobiodiversity? : patterns of species distribution, planting material flow and knowledge transmission along the Corrientes River of the Peruvian Amazon

Perrault-Archambault, Mathilde January 2005 (has links)
Agrobiodiversity constitutes an essential resource for traditional rural populations. Home gardens are "hotspots" of agrobiodiversity and important loci of in situ conservation efforts. This study seeks to understand the factors affecting gardeners' choices and to assess the accessibility of planting material in rural communities of the Peruvian Amazon. Household surveys and garden inventories conducted in 15 villages of the Corrientes river (n = 300), and case studies in three of these villages (n = 89), allowed to describe the local and regional patterns of garden agrobiodiversity and the structure of planting material exchange networks. Analyses reveal a strong link between species diversity and both household cultural and socioeconomic characteristics, and village ethnicity and size. Planting material flows primarily through matrilineal bonds, from advice-givers to advice-seekers, from old to young and from rich to poor. Farmers with exceptional species diversity, propensity to give and/or expertise are identified and their role in the conservation of cultivated plants is assessed. Expertise is not found to be as closely related to high species diversity as expected, but knowledge and planting stock dissemination go hand-in-hand.
34

Home gardens, cultivated plant diversity, and exchange of planting material in the Pacaya-Samiria National Reserve area, northeastern Peruvian Amazon

Lerch, Natalie Corinna. January 1999 (has links)
No description available.
35

Who manages home garden agrobiodiversity? : patterns of species distribution, planting material flow and knowledge transmission along the Corrientes River of the Peruvian Amazon

Perrault-Archambault, Mathilde January 2005 (has links)
No description available.
36

Carbon and nitrogen cycling in the Peruvian Andean Amazon

Townsend-Small, Amy, 1976- 12 August 2011 (has links)
Not available / text
37

Climatic impact of Amazon deforestation: A study of underlying mechanism through simple modeling.

Zeng, Ning. January 1994 (has links)
An intermediate level model for tropical climatology including atmosphere-land-ocean interaction is developed. The model contains basically linearized steady state primitive equations with simplified thermodynamics. A simple hydrological cycle is also included. Special attention has been paid to land surface processes in attempting to study climate change caused by Amazon deforestation. In comparison with previous simple modeling work on tropical climatology or anomaly, the present model is more sophisticated in the sense that it predicts all the important meteorological variables with little input, while being computationally simple. The modeled tropical climatology appears to be realistic. The model generally better simulates the ENSO anomaly compared to many previous simple model simulations. We provide analysis of model results and discuss model deficiencies and possible improvements of the model. The climatic impact of Amazon deforestation is studied in the context of this model. Model results show a much weakened Atlantic Walker/Hadley circulation as a result of the existence of a strong positive feedback loop in the atmospheric circulation system and the hydrological cycle. The regional climate is very sensitive to albedo change and sensitive to evapotranspiration change. The pure dynamical effect of surface roughness on convergence is small, but the surface flow anomaly displays intriguing features. Analysis of the thermodynamic equation reveals the balance among convective heating, adiabatic cooling and radiation largely determines the deforestation response. The model provides a plausible mechanism for the common results of many GCM simulations. Studies of the consequences of hypothetical continuous deforestation suggest that the replacement of forest by desert may be able to sustain a desert-like climate. When a simple mixed layer ocean model is coupled with the atmospheric model, the results suggest a 1 °C decrease in SST gradient across the equatorial Atlantic ocean in response to Amazon deforestation. The magnitude of the decrease depends on the coupling strength.
38

As the forest falls : the changing use, ecology and value of non-timber forest resources for Caboclo communities in eastern Amazonia

Shanley, Patricia January 2000 (has links)
No description available.
39

Kindle: Changing the Publishing Industry

Ngo, Toan 01 May 2013 (has links)
Amazon.com, Inc. (AMZN), headquartered in Seattle, Washington, is the world’s largest online retailer (Jopson, 1). The company’s website launched in the United States in 1994 by Jeffrey Bezos as an online bookstore, later diversified to offer a broad line of products in multiple warehouses across the US. With successful expansion, Amazon.com is now available worldwide in Canada, the United Kingdom, Germany, France, Italy, Spain, Japan, Brazil and China (SECdatabase, 50). The company directly sells or acts as a third – party to deliver the products to customers. As of the first quarter in 2011, Amazon has approximately 137 million active customers worldwide (Szkutak, 1). In 2007, CEO Jeff Bezos lead Amazon in a new direction by introducing the eReaderKindle, offering a new platform for digital books and other e-print media. The Kindle allows users to read, shop for, download and browse eBooks, newspaper, magazines, blogs and websites using Wi-Fi. The 3G Kindle uses Sprint’s 3G cellular services to allow immediate customer purchase and download from the Amazon Kindle store, with no connectivity charges. The base model e-ink Kindle features a 6” screen, while the Kindle DX has a 10” screen and the newly introduced Kindle Fire has 7” multi-touch colored screen. The Kindle is designed for people who favor a small, compact electronic device to carry in their pockets or bags. The purpose of this paper is to detail the development, technology, opportunities as well as challenges associated with Amazon Kindle in relate to the publishing industry. The paper also discusses whether the 6” eReader device will change reading habits and its impact on hardcopy publishing businesses worldwide.
40

Molekulargenetische und zytogenetische Untersuchungen zur paternalen Introgression beim gynogenetischen Amazonenkärpfling, Poecilia formosa / Molecular and cytogenetic analysis of paternal introgression in the gynogenetic Amazon molly, Poecilia formosa

Lamatsch, Dunja January 2001 (has links) (PDF)
Die Frage nach der Entstehung und Beibehaltung von sexueller Reproduktion nimmt in der Biologie eine zentrale Stellung ein. Dazu werden seit langem die Vor- und Nachteile asexueller Fortpflanzung diskutiert, da man sich von einer vergleichenden Betrachtungsweise wichtige Aufschlüsse erwartet. Dem kurzfristigen Vorteil der schnelleren Vermehrung stehen langfristige Nachteile entgegen: Aufgrund fehlender genetischer Rekombinationsprozesse können sich schädliche Mutationen im Laufe der Generationen anhäufen ("Muller’s ratchet"), und schnelle Anpassung an eine veränderte Umwelt oder neue Abwehrstrategien gegen Parasiten werden erschwert. Der Amazonenkärpfling, Poecilia formosa, stellt einen Organismus dar, dessen Fortpflanzung in Folge eines interspezifischen Hybridisierungsereignisses vom üblichen bisexuellen Muster abweicht: Es treten normalerweise nur Weibchen auf, die sich gynogenetisch vermehren. Hierbei werden die unreduzierten diploiden Eizellen durch Spermien sympatrisch vorkommender sexueller Wirtsmännchen nahe verwandter Arten (P. latipinna oder P. mexicana) stimuliert, um eine parthenogenetische Entwicklung der Embryonen zu initiieren. Es findet keine Karyogamie statt, so daß die Nachkommen in der Regel untereinander und mit ihren Müttern genetisch identisch (klonal) sind. Molekularbiologische Untersuchungen ergaben jedoch, daß P. formosa wesentlich älter ist, als dies auf der Basis von "Muller’s ratchet" zu erwarten war. Eine mögliche Erklärung dafür wäre, daß in seltenen Fällen väterliches Erbmaterial an die Nachkommen weitergegeben werden kann (paternale Introgression). Sowohl in natürlichen Lebensräumen als auch unter Laborbedingungen konnten nur zwei Formen paternaler Introgression identifiziert werden: Kommt es aufgrund von Karyogamie zu einer tatsächlichen Befruchtung der diploiden Oozyte durch das haploide Spermium entstehen triploide Individuen. In anderen Fällen verbleiben nach der Aktivierung durch das artfremde Spermium nur geringe DNA-Mengen in der Oozyte, die in den Kern aufgenommen werden und im Karyotyp als überzählige Chromosomen, sog. Mikrochromosomen, zu identifizieren sind. Die beiden Formen paternaler Introgression können jedoch auch kombiniert vorliegen. In diesen Fällen entwickelten sich die Individuen überraschenderweise zu phänotypischen Männchen. Die vorliegenden Ergebnisse über paternale Introgression können zur Aufklärung der Frage beitragen, warum P. formosa und andere asexuelle Organismen offenbar länger überlebten, als vorhergesagt. Im Gegensatz zu den bisherigen Annahmen könnte es sich bei spermienabhängiger Parthenogenese nicht etwa nur um eine unvollkommene Parthenogenese handeln, sondern um einen gut angepaßten Fortpflanzungsmodus, der die Vorteile von asexueller mit denen sexueller Fortpflanzung kombiniert. / One of the greatest challenges in evolutionary biology is explaining the widespread occurrence of sexual reproduction and the associated process of genetic recombination. Comparing the advantages and disadvantages of sexual and asexual reproduction is expected to give major insights to that "queen of questions". Whereas asexual females have the short term advantage of producing twice as many daughters as sexual females, they are also expected to suffer from long-term constraints: Due to the absence of genetic recombination, asexuals are prone to accumulate deleterious mutations (Muller´s ratchet), and adaptation to changing environments or the escape from parasite load will be aggravated. The Amazon molly, P. formosa, resembles an organism which shows an alternative reproductive mode to the ubiquitous bisexual reproduction. Being an all-female species due to interspecific hybridization, it reproduces gynogenetically: Unreduced diploid eggs are only activated by sperm of males of closely related sympatric species. Without karyogamy the oocytes develop parthenogenetically leading to genetically identical (clonal) offspring. Molecular phylogenetic data suggest that P. formosa might have survived longer than predicted by Muller´s ratchet. To explain this paradox, two phenomena which have been observed in natural populations as well as in laboratory broods are taken into consideration: Triploidy and occurrence of microchromosomes as a consequence of paternal introgression. Triploidy results from the successful insemination of the unreduced diploid eggs with haploid host sperm and subsequent karyogamy, whereas microchromosomes are small supernumerary chromosomes that seem to be the left over of the enzymatic machinery which normally clears the egg from the sperm nucleus after activation has occurred. Both forms of paternal introgression may also occur in combination. Surprisingly, these individuals developed spontaneously into males. The results on paternal introgression obtained here can contribute to answer the question why P. formosa as well as other unisexual vertebrates survived longer than predicted. Contradictory to common knowledge, gynogenesis might not be an imperfect parthenogenesis but a well adapted reproductive mode combining the advantages of asexual and sexual reproduction.

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