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There is a polarised debate amongst Neotropical archaeologists and ecologists over the extent of Pre-Columbian (pre-AD 1492) anthropogenic environmental impacts in Amazonia. While some maintain the old paradigm of pre-Columbian Amazonia as a “pristine wilderness”, which was sparsely populated by humans, others point to the discovery of an increasing number of archaeological sites across the Amazon basin as evidence for large, complex societies, supported by intensive agriculture and management of forest and aquatic resources. Under this model, pre- Columbian people had profound impacts on biogeochemical cycles through largescale deforestation and biomass burning, and left an indelible legacy on Amazonian ecosystems by altering edaphics, geomorphology, hydrology, and the distribution of plant taxa. However, so far this debate has continued amongst a paucity of palaeoecological data, meaning that we have little evidence to indicate the scale of impact, and often no palaeoenvironmental context in which to place these societies. Other aspects of pre-Columbian cultures, such as their chronology, land use practices and subsistence strategies, are also poorly understood. In this thesis, palaeoecological methods are applied to improve our understanding of the scale, nature, and legacy of land use associated with pre- Columbian geometric earthwork cultures in north-east Bolivia. The methodology employs analysis of fossil pollen and macroscopic charcoal from lake core sediments. In total 110 pollen and 628 charcoal samples were analysed from four lakes: Laguna Isireri (14°49’18”S, 65°40’57”W), Laguna Orícore (13°20’44”S, 63°31’31”W), Laguna Granja (13°15’44”S, 63°42’37”W) and Laguna La Luna (13°21’20”S, 63°35’2”W). Chronologies were built for these cores from 12 AMS 14C dates. Results are presented in four chapters (thesis chapters 2-5), in the form of academic papers. Chapter 2 describes a new laboratory technique co-developed with Whitney et al., which improves the recovery of cultigen pollen grains from sediments from large, Neotropical lake basins. This technique was applied in the laboratory preparations of sediments analysed for Chapters 3-5. Chapter 3 employs palaeoecological reconstructions from differently sized lakes (L. Granja and L. Orícore) in the same earthwork region, to obtain both a regional- and a local-scale history of environmental change/human impact around the archaeological site. Key findings of this paper are: 1) earthworks were built in an originally open savannah landscape, which existed under drier-than-present climatic conditions in the mid-to-late-Holocene; 2) forest expanded into this region from ~ 2000 (cal yrs) BP and was supressed locally around the settlement to maintain an open landscape; therefore, 3) earthwork construction across southern Amazonia, may not have required extensive deforestation, and pre-Columbian impacts on biogeochemical cycling may have been much less than some authors have suggested. Chapter 4 looks more closely at the local scale record provided by L. Granja. These data are integrated with phytolith data analysed by co-author J. Watling and existing archaeological data, to discuss the chronology of settlement on the site, the agricultural/land use strategies employed by its inhabitants, and the spatial scale and distribution of impacts locally around the site. Key findings are that: 1) first occupation of the site is much earlier than previously dated from archaeological contexts, beginning ~2500 BP; 2) maize was the staple crop grown on site; 3) land use involved more extensive and intensive burning of the landscape than compared to modern slash-and-burn agriculture; 4) site decline occurred ~ 500 BP, and may have been related to the Columbian Encounter of AD1492; 5) the close integration of local scale palaeoecological records with archaeology, is highly useful in discerning aspects of chronology and spatial variability of land use. Chapter 5 presents a 6000 year record of palaeoenvironmental change and land use on a pre-Columbian forest island site. Key findings are that: 1) As in Chapter 3, inhabitants exploited an originally open landscape and practiced forest suppression to maintain that open landscape; 2) the earliest recorded evidence for maize agriculture in the region is found at 2100 BP; 3) the economically useful species Theobroma cacao, which is abundant on the site today, is not detectable in the pollen record; 4) clear-cutting was not practiced on the site and previous population estimates, based on labour for deforestation, must be reconsidered. The work in this thesis reveals a new model of human-environment interactions, demonstrating that pre-Columbian earthwork cultures in southern Amazonia occupied and adapted to a region of dynamic, climatically controlled forest-savannah transition during the mid-to-late-Holocene. Obtaining a palaeoenvironmental context for archaeological landscapes, is shown to be a vital pre-requisite to inferring past environmental impacts. Furthermore, we demonstrate the valuable contribution that palaeoecology can make to a better understanding of the chronology and land use practices of pre-Columbian cultures.

This paper documents the differences in pricing strategies between online and offline (brick-and-mortar) channels. We collect price data for identical products from leading online grocery retailers in the United States and complement it with offline data for the same products from scanner data. Our findings reveal a consistent pattern: online retailers exhibit higher price dispersion than their offline counterparts. More specifically, online grocers employ price algorithms that amplify price discrimination in three key dimensions: (1) over time (through frequent price changes), (2) across locations (by charging varying prices based on delivery zipcodes), and (3) across sellers (by setting dispersed prices for identical products across rival retailers).

The advent of cloud computing has decreased the cost of enterprise level system design and implementation, while at the same time increasing the need for a sound and secure strategy for security. The use of encryption algorithms continues to be the main line of defense in performing secure data transmissions, the use of a Cloud Computing environment offers both advantages and disadvantages in the encryption process. Though the new series of encryption algorithms are quite robust, they require a “key” to make their use unique for an individual session, thus if the key is compromised then the underlying encryption algorithm can be broken. In a classically designed system, the entire cryptographic key is contained on one node within the network, if this node is compromised even though robustly protected the the entire network would be at risk. The flip side to the potential breaking in dilemma outlined above is perhaps an even scarier option, one in which the node on which the key is kept is corrupted either through malicious intent, unintended mishap, or simple system failure. This scenario opens up the possibility that the key is unrecoverable, in which case the data that has been encrypted with the cryptographic key may be rendered unrecoverable as well. In this paper I looked at how a distributed key system, broken up over varying numbers of multiple nodal instances, and distributed across the Amazon Web Services (AWS) Cloud reacted and performed their intended task of authenticating a web service.

The family Polycentropodidae occurs worldwide, and is represented in the Americas by Cernotina Ross 1938, Cyrnellus Banks 1913, Nyctiophylax Brauer 1865, Polycentropus Banks 1907 and Polyplectropus Ulmer 1905. Cernotina and Cyrnellus are exclusive to the New World, reaching their highest diversity in the Neotropics, with 75 and 12 described species respectively. Despite this diversity, none of the two have had revisionary work done, and the taxonomic information is scattered in many different papers by many authors across the 20th and early 21st Century. In Chapter 1, I ran the first phylogenetic analyses on the diverse genus Cernotina, using morphological characters of the male adult, especially the genitalia. To analyze the character matrix, I used Maximum Parsimony and Bayesian inference. In Maximum Parsimony, I used equally-weighted analyses with two different search strategies, one simple run and another with multiple rounds saving suboptimal trees to filter for a better set of most parsimonious trees, and an implied-weights analysis, using a posteriori character weigthing to achieve better resolution. In the Bayesian inference, I used Mk model + lognormal distribution, commonly used in morphological data. The results suggest the monophyly of Cernotina, adds phylogenetic evidence for synonymization of Ce. perpendicularis with Ce. lanceolata, and Ce. hastilis with Ce. nigridentata, and group certain species with morphological and geographic congruence, such as Ce. acalyptra + Ce. cystophora + Ce. encrypta, and Ce. lutea + Ce. cadeti, respectively. However, the overall resolution of the simple maximum-parsimony and the Bayesian trees were very low. In addition, the branch support for most nodes is also very low. This result might be due to the nature of the genitalic characters of Cernotina, being extremely variable on all its components, making the task of finding character congruence difficult. With additional data such as DNA sequence and geometric morphometrics, such issues could be alleviated. In Chapter 2, I revised the genus Cernotina at species-level. I discussed the complex homology of the morphological characters of the male genitalia, especially concerning the intermediate appendage and its relation to the Xth tergum and the preanal appendage, produced illustrations and comparative diagnoses for each species in the genus, and taxonomic descriptions for 64 species. In addition, I described 16 new species. I also proposed 2 synonymies considering the phylogenetic data from Chapter 1: Ce. lanceolata as junior synonym of Ce. perpendicularis, and Ce. nigridentata as junior synonym of Ce. hastilis. In Chapter 3, I revised the genus Cyrnellus at species-level. I also discussed the homology of the morphological characters of the much simpler male genitalia of the genus, produced a key to species of Cyrnellus, provided illustrations, and full taxonomic descriptions for 11 species. In addition, I reinstated the validity of Cy. minimus based on the morphology of the inferior appendage in ventral view. I also synonymized 2 species based on morphological similarity and high variability among specimens: Cy. keskes as junior synonym of Cy. minimus, and Cy. kozepes as junior synonym of Cy. ulmeri.

In the middle of the eighteenth century the Portuguese crown, under the influence of the Marquis of Pombal, sought to reform the political administration of its vast set of imperial holdings. As part of these reforms, in 1751 Pombal sent his brother, Francisco Xavier de Mendonça Furtado, to the Portuguese Amazon to serve as governor of the state of Grão Pará and Maranhão. This study explores Furtado’s tenure as governor of the Amazon from his perspective, in an attempt to understand how and why he arrived at a set of policies known as the “Directorate,” which overhauled the region’s mission system and attempted to more effectively assimilate native Amazonians into Portuguese colonial society. Chapter One combines a look at Furtado’s initial years as governor with short digressions into the relevant historical background of the region. The analysis in this chapter focuses on Furtado’s influence on his brother, the Marquis of Pombal, as well as the early attempts at reform he pursues out of a growing sense of frustration with the Jesuit missionaries in the region. Chapter Two focuses on a long trip Furtado took upriver to a settlement called Mariuá, in order to negotiate the boundary demarcation with Spain. Over the course of two years away from his home in Belém at the mouth of the Amazon, Furtado’s opinion of the Indians evolves, influencing the implementation of the Directorate policy upon his return. The paper concludes with a brief discussion of the legacies of Furtado and the Directorate.