Environmental Migrants: Considerations for the U.S. Government

Climate change threatens to force population displacement on a scale never seen before. Unfortunately, many governments, international organizations, and institutions are currently ill-prepared and unequipped to respond to this challenge. To buffer the United States from these potentially seismic shifts, it is advisable that the plight of environmental migrants receive serious consideration and advanced planning

Manipulation of Ga2O3 Nanocrystals for the Design of Functional Phosphors

Transparent conducting oxides are of great interest in semiconductor research and industry. Their ability to carry electricity while remaining transparent allows them to be used for different applications including photovoltaics, lighting, and photocatalysis. Among transparent conducting oxides, Ga2O3 has the widest band gap and is characterized by a strong broad-band blue-green afterglow emission, making it attractive for various lighting applications. The main motivation of this thesis is to use these unique properties of Ga2O3 to design new phosphors with targeted optical properties. The research described in this thesis specifically focuses on generating white light by non-radiative energy transfer between Ga2O3 nanocrystals, as energy donors, and orange-red emitting semiconductor quantum dots, as energy acceptors, and using dopant-induced trap states to extend afterglow emission. Solution phase conjugation of colloidal nanocrystals allows for short-range energy transfer processes to occur with high probability, which is valuable for sensing and lighting. The first part of this thesis demonstrates the conjugation and electronic coupling of Ga2O3 nanocrystals with CdSe/CdS core/shell quantum dots. The introduction of a bifunctional organic ligand to the suspension mixture of these nanocrystals allows for their conjugation. The resulting Förster resonance energy transfer leads to quenching of Ga2O3 emission and an increase in the emission of CdSe/CdS quantum dots. As the ratio of CdSe/CdS quantum dots to Ga2O3 nanocrystals increases, so does the quenching of Ga2O3 emission and the CdSe/CdS photoluminescence intensity. The increase in quenching of Ga2O3 emission was successfully modelled assuming a Poisson distribution of CdSe/CdS quantum dots bound to Ga2O3 nanocrystals. Owing to the good emission colour complementarity of these materials, white light was observed for optimal nanoconjugate composition. Next, we demonstrated that the same phenomenon can be achieved without the organic linker by a careful deposition of the colloidal mixture on the glass substrate to remove the empty space between nanocrystals. This approach enables a surface-mediated Förster resonance energy transfer that allows for a design of all-inorganic white light emitting phosphors. The resulting films were highly luminescent and were tuned to give CIE coordinates of 0.31, 0.28. Gallium oxide also has a long luminescence lifetime, compared to other nanoparticles with similar emission strengths, enabled by its donor-acceptor pair recombination. This phenomenon makes Ga2O3 nanocrystals a prime candidate for attempting to design persistent afterglow nanophosphors through doping nanocrystals with selected trivalent rare earth metals. These rare earth elements provide a mechanism for trapping excited free carriers because relaxation within these dopant ions is Laporte forbidden. As a result of doping Ga2O3 with Dy3+, the emission of Ga2O3 nanocrystals becomes significantly longer at room temperature. More interestingly, the temperature-dependent emission of Ga2O3 nanocrystals doped with Dy3+ for doping levels between 3 and 13 % increased between 50 K and 200 K, where typical semiconducting nanocrystals show strong quenching. We attribute this anomalous behavior to the carriers trapped in Dy3+ excited states, that are thermally reactivated and subsequently relax to Ga2O3 native traps states. This assignment was validated by a kinetic Monte Carlo simulation, which was in good agreement with experimental results. As the importance of luminescence materials, particularly persistent phosphors, increases it is imperative that undergraduate students in chemistry and materials science become familiar with their properties and fabrication. A new laboratory exercise encompassing the combustion synthesis, processing, and characterization of SrAl2O4:(Eu2+, Dy3+) has been adopted by NE 320L course in the Nanotechnology Engineering program at the University of Waterloo. In this laboratory, students produced crude strontium aluminate containing Eu3+ which was subsequently annealed under hydrogen gas, resulting in the red europium emission. This emission becomes green upon reduction of Eu3+ to Eu2+. Students performed XRD showing a dramatic increase in crystallinity after annealing, while their SEM measurements did not show a significant change in morphology. Mechanoluminescence was observed using a ballistic setup and found to show a linear dependence on the projectile velocity. In this thesis I demonstrated the extrinsic (external functionalization) and intrinsic (doping) manipulation of the electronic structure of gallium oxide nanocrystals. The obtained results allow for technological application of the resulting materials (e.g., to generate white light and extend afterglow emission), and provide a framework to enrich upper-year undergraduate curriculum in materials science and nanotechnology

Lake Titicaca: Legend, Myth and Science

Lake Titicaca and the vast region surrounding this deep body of water contain mysteries that we are just beginning to unravel. The area surrounding the world’s highest navigable lake was home to some of the greatest civilizations in the ancient world. These civilizations were created by the ancestors of the Aymara and Quechua peoples who continue to live and work in Peru and Bolivia along the shores of this ancient body of water. This lavishly illustrated book provides a state-of-the-art description and explanation of the great cultures that inhabited this land from the first migrants ten millennia ago to the people who thrive here today. We will also discover the world of myth and legend that has grown up around this mysterious place, including the lost continent of Mu, the land of Paititi, El Dorado and the many mystic ruins of Titicaca. We then explore the results of a century of scientific research that provide an even more fabulous tale than the legends and myths combined. This book is an indispensable guide for any visitor who has an interest in archaeology, history and culture. It is likewise an excellent introduction for the interested reader who yearns to know more about this fascinating place.Series: World Heritage and Monument

Gospel Encounter With Subaltern India

This work examines the role of religio-cultural resources in enabling the transformation of a broken community and people. In the context of nineteenth and twentieth century British India, an oppressed community in India set out to explore the possibility of challenging and re-defining their own destiny. This oppressed section of Indians who lived in the margins of Indian caste defined society were considered socially and ritually polluting people and were subservient to various socio-economic and religio-cultural biases. The daily life routine of this oppressed community, called the Sambavars (Pariahs) of the Malayalam speaking princely State of Travancore in South India, involved a despair and inferiority instilling encounter against hegemonic and fearful social and religio-cultural forces. However, in the churning socio-political period of twentieth century British India, a group of Malayalee Sambavars driven by their own critical consciousness took the initiative of approaching and inviting Lutheran Church—Missouri Synod missionaries working among their Tamil speaking kinsmen in Nagercoil on the southern tip of India. The ensuing chain of events ultimately culminated in the formation of the India Evangelical Lutheran Church in the state of Kerala, along the southwestern coast of India. By looking into the mission phase of the India Evangelical Lutheran Church (called Missiouri Evangelical Lutheran India Mission [MELIM] at that time) through the lens of gospel-culture interaction, this dissertation attempts to unveil the mission story from the perspective of the oppressed people who initiated and formed the majority converts in the mission. This dissertation argues that the MELIM period saw an interesting cross-cultural interaction between the American Lutheran missionaries and the native converts. In the midst of enthusiasm, mis-understandings, disillusionment and suffering on both sides; the gospel was preached and the Lutheran Church established in the Malayalam lands. More importantly, this gospel-culture engagement triggered a latent native Lutheran theological reflection that resourcefully spoke to the concerns of native believers, providing them with hope and strength for a meaningful present and a blessed future

Evolutionary vs. Sociocultural Perspectives on Human Mate Selection: The Role of Women\u27s Academic Achievement on Their Need for Financial Stability

Recent research suggests that the sociocultural perspective has become more prominent than the previously accepted evolutionary perspective of human mate selection (Wood, 1999; Tooby & Cosmides, 1992). Today\u27s women have higher educational attainment and overall higher achievement levels than in the past (Blank & Bansal, 2011; Osava, 2010). The purpose of the current study is to determine if college women exhibit more of a sociocultural or evolutionary approach to their mate selection preferences. Approximately 109 female undergraduates completed the Relationship Preferences Questionnaire, on which they rated 10 attributes of a potential mate on a 6-point scale. Participants\u27 ACT scores and cumulative grade point averages provided measures of aptitude and achievement, respectively. Results of targeted variables showed no significant results associated with academic achievement levels. However compared to past findings, these results support a sociocultural theory of mate selection in women

Local Entities as Mechanisms for Global Climate Governance

This paper considers the role of local government entities as actors in global climate governance regimes. The authors review traditional state-based climate governance efforts and existing attempts to engage municipal and local actors through transnational municipal networks (TMNs). Arguing for the importance of TMNs to effective and time-sensitive climate action, the authors then show how and why TMNs are crucial to future efforts to address climate mitigation as part of multi-level, holistic plans for global climate governance