Water quality trading: credit stacking and ancillary benefits

Ecosystems can provide many services. Wetlands, for example, can help mitigate water pollution from point sources as well as non-point sources, serve as habitat for wildlife, sequester carbon and serve as a place for recreation. Studies have found that these services can have substantial value to society. The sale of ecosystem credits has been found to be a possible way to finance construction investments in wetlands and easements to farmers to take their land out of production. At the same time, selling one ecosystem service credit may not always be enough to justify the investment. Traditionally market participants have only been allowed to sell a single credit from one piece of land, but recently there have been discussions about the possibility of selling more than one credit from a piece of land because it potentially could lead to more efficient ecosystem service provision. Selling multiple credits is sometimes referred to as credit stacking. This paper is an empirical study of the potential for credit stacking applied to the services provided by wetlands in the Upper Mississippi River Basin, specifically nitrogen, phosphorus and wildlife credits. In the setting of our study where costs are discrete rather than continuous we found that wetlands are a cost-effective way to reduce the nitrogen loads from wastewater treatment plants and that stacking nitrogen, phosphorus and wildlife credits may improve social welfare while leading to a higher level of ecosystem services. However, for credit stacking to be welfare improving we found that there needs to be a substantial demand for the credit that covers the majority of the investment in wetlands, while the credit aggregator has a choice between what ecosystem projects to undertake. If the credit that covers the majority of investment is sold first and is the sole basis of the investment decision and the objective is to improve welfare, a sequential implementation of ecosystem credits is not recommended; it would not lead to an increase in the total amount of ecosystem services provided though it would increase profit for the credit producer.

Design and development of distributed feedback transistor lasers

The transistor laser is a unique three-port device that operates simultaneously as a transistor and a laser. With quantum wells incorporated in the base regions of heterojunction bipolar transistors, the transistor laser possesses advantageous characteristics of fast base spontaneous carrier lifetime, high differential optical gain, and electrical-optical characteristics for direct “read-out” of its optical properties. These devices have demonstrated many useful features such as high-speed optical transmission without the limitations of resonance, non-linear mixing, frequency multiplication, negative resistance, and photon-assisted switching. To date, all of these devices operate as multi-mode lasers without any type of wavelength selection or stabilizing mechanisms. Stable single-mode distributed feedback diode laser sources are important in many applications including spectroscopy, as pump sources for amplifiers and solid-state lasers, for use in coherent communication systems, and now as TLs potentially for integrated optoelectronics. The subject of this work is to expand the future applications of the transistor laser by demonstrating the theoretical background, process development and device design necessary to achieve singlelongitudinal- mode operation in a three-port transistor laser. A third-order distributed feedback surface grating is fabricated in the top emitter AlGaAs confining layers using soft photocurable nanoimprint lithography. The device produces continuous wave laser operation with a peak wavelength of 959.75 nm and threshold current of 13 mA operating at -70 °C. For devices with cleaved ends a side-mode suppression ratio greater than 25 dB has been achieved.

Quichua-Spanish language contact in Salcedo, Ecuador: revisiting media lengua syncretic language practices

The purpose of the current thesis is to develop a better understanding of the interaction between Spanish and Quichua in the Salcedo region and provide more information for the processes that might have given rise to Media Lengua, a ‘mixed’ language comprised of a Quichua grammar and Spanish lexicon. Muysken attributes the formation of Media Lengua to relexification, ruling out any influence from other bilingual phenomena. I argue that the only characteristic that distinguishes Media Lengua from other language contact varieties in central Ecuador is the quantity of the overall Spanish borrowings and not the type of processes that might have been employed by Quichua speakers during the genesis of Media Lengua. The results from the Salcedo data that I have collected show how processes such as adlexification, code-mixing, and structural convergence produce Media Lengua-type sentences, evidence that supports an alternative analysis to Muysken’s relexification hypothesis. Overall, this dissertation is developed around four main objectives: (1) to describe the variation of Spanish loanwords within a bilingual community in Salcedo; (2) to analyze some of the prominent and recent structural changes in Quichua and Spanish; (3) to determine whether Spanish loanword use can be explained by the relationship consultants have with particular social categories; and (4) to analyze the consultants’ language ideologies toward syncretic uses of Spanish and Quichua. Overall, 58% of the content words, 39% of the basic vocabulary, and 50% of the subject pronouns in the Salcedo corpus were derived from Spanish. When compared to Muysken’s description of highlander Quichua in the 1970’s, Spanish loanwords have more than doubled in each category. The overall level of Spanish loanwords in Salcedo Quichua has grown to a level between highlander Quichua in the 1970’s and Media Lengua. Similar to Spanish’s lexical influence in Media Lengua, the increase of Spanish borrowings in today’s rural Quichua can be seen in non-basic and basic vocabularies as well as the subject pronoun system. Significantly, most of the growth has occurred through forms of adlexification i.e., doublets, well-established borrowings, and cultural borrowings, suggesting that ‘ordinary’ lexical borrowing is also capable of producing Media Lengua-type sentences. I approach the second objective by investigating two separate phenomena related to structural convergence. The first examines the complex verbal constructions that have developed in Quichua through Spanish loan translations while the second describes the type of Quichua particles that are attached to Spanish lexemes while speaking Spanish. The calquing of the complex verbal constructions from Spanish were employed when speaking standard Quichua. Since this standard form is typically used by language purists, I argue that their use of calques is a strategy of exploiting the full range of expression from Spanish without incorporating any of the Spanish lexemes which would give the appearance of ‘contamination’. The use of Quichua particles in local varieties of Spanish is a defining characteristic of Quichuacized Spanish, spoken most frequently by women and young children in the community. Although the use of Quichua particles was probably not the main catalyst engendering Media Lengua, I argue that its contribution as a source language to other ‘mixed’ varieties, such as Media Lengua, needs to be accounted for in descriptions of BML genesis. Contrary to Muysken’s representation of relatively ‘unmixed’ Spanish and Quichua as the two source languages of Media Lengua, I propose that local varieties of Spanish might have already been ‘mixed’ to a large degree before Media Lengua was created. The third objective attempts to draw a relationship between particular social variables and the use of Spanish loanwords. Whisker Boxplots and ANOVAs were used to determine which social group, if any, have been introducing new Spanish borrowings into the bilingual communities in Salcedo. Specifically, I controlled for age, education, native language, urban migration, and gender. The results indicate that none of the groups in each of the five social variables indicate higher or lower loanword use. The implication of these results are twofold: (a) when lexical borrowing occurs, it is immediately adopted as the community-wide norm and spoken by members from different backgrounds and generations, or (b) this level of Spanish borrowing (58%) is not a recent phenomenon. The fourth and final objective draws on my ethnographic research that addresses the attitudes of syncretic language use. I observed that Quichuacized Spanish and Hispanicized Quichua are highly stigmatized varieties spoken by the country’s most marginalized populations and families, yet within the community, syncretic ways of speaking are in fact the norm. It was shown that there exists a range of different linguistic definitions for ‘Chaupi Lengua’ and other syncretic language practices as well as many contrasting connotations, most of which were negative. One theme that emerged from the interviews was that speaking syncretic varieties of Quichua weakened the consultant’s claim to an indigenous identity. The linguistic and social data presented in this dissertation supports an alternative view to Muysken’s relexification hypothesis, one that has the advantage of operating with well-precedented linguistic processes and which is actually observable in the present-day Salcedo area. The results from the study on lexical borrowing are significant because they demonstrate how a dynamic bilingual speech community has gradually diversified their Quichua lexicon under intense pressure to shift toward Spanish. They also show that Hispanicized Quichua (Quichua with heavy lexical borrowing) clearly arose from adlexification and prolonged lexical borrowing, and is one of at least six identifiable speech styles found in Salcedo. These results challenge particular interpretations of language contact outcomes, such as, ones that depict sources languages as discrete and ‘unmixed.’ The bilingual continuum presented in this thesis shows on the one hand, the range of speech styles that are accessible to different speakers, and on the other hand, the overlapping, syncretic features that are shared among the different registers and language varieties. It was observed that syncretic speech styles in Salcedo are employed by different consultants in varied interactional contexts, and in turn, produce different evaluations by other fellow community members. In the current dissertation, I challenge the claim that relexification and Media Lengua-type sentences develop in isolation and without the influence of other bilingual phenomena. Based on Muysken's Media Lengua example sentences and the speech styles from the Salcedo corpus, I argue that Media Lengua may have arisen as an institutionalized variant of the highly mixed "middle ground" within the range of the Salcedo bilingual continuum discussed above. Such syncretic forms of Spanish and Quichua strongly resemble Media Lengua sentences in Muysken’s research, and therefore demonstrate how its development could have occurred through several different language contact processes and not only through relexification.