Optical Characterization of Antimony-Based, Types-I and II, Multiple Quantum-Well Semiconductor Structures for Mid-Infrared Laser Applications

This experiment characterizes antimony-based, multiple quantum-well, types-I and -II, semiconductor samples designed for laser applications. The samples emit light in the 3-5-micron range to exploit an atmospheric transmission window, making them ideal for infrared (IR)-seeking missile countermeasures. Photoluminescence (PL) spectra were collected and yielded bandgap (E(sub g)) dependence-on-temperature relationships. The type-I sample was found to follow the Varshni equation, while the type-II samples showed a rise with temperature in a portion of the curve that should be linear according to the Varshni equation. The type-II samples followed the Varshni equation well at higher temperature. The PL study indicated that the type-I sample had better efficiency than the type-II samples, and that there is some change in efficiency with the waveguide nature of the sample. Carrier temperatures (T(sub c)) were derived from the PL study; all the samples for which Tc was derived operated in the optical phonon regime. The PL data were compared to the FEMB computer model and some correlation between the two in recombination energy was seen. A time-resolved photoluminescence (TRPL) experiment was conducted using the frequency upconversion technique. The experiment clearly found the upconverted signal, but there was a systematic error that prevented any further analysis of the data

The use of altrenogest to control reproductive function in beef cattle

There has been great controversy involving progesterone (P4) levels during early pregnancy in cattle. The objectives of these experiments were to determine the effect of an early low dose administration of P4 or altrenogest (ALT) on pregnancy rates in repeat breeder (RPB) females, if an increase in pregnancy rates could result from a direct effect of P4 on the embryo and if ALT could support pregnancy in the absence of a functional CL. Firstly, ALT was evaluated for use as a progestin in cattle by synchronizing estrus in beef heifers. There were no differences in the number of females displaying behavioral estrus or in pregnancy rates when synchronized with ALT or MGA. A second experiment was designed to determine the effect of P4 or ALT supplementation during days 3 to 5 on pregnancy rate in RPB cattle. It was determined that 15 mg of P4 or ALT during days 3 to 5 increased pregnancy rates compared with nontreated breeding periods. A third experiment was designed to determine if P4 exerted a direct effect on the embryo. In vitro produced (IVP) embryos were cultured in the absence of a co-culture system. At day 3, post-insemination, embryos were cultured in the presence of P4 and evaluated on days 6 to 9. On day 7 post-insemination, there were significantly more grade 1 blastocysts from the P4 group compared with other treatment groups. Also, embryo developmental rates were increased when cultured in the presence of P4 and more of these embryos developed to the hatched blastocyst stage compared with other treatment groups. After a direct effect of P4 on developing IVP bovine embryos existed, it was determined that these embryos did not possess P4 receptors. Finally, it was demonstrated that ALT could support pregnancy in the absence of a functional CL. These experiments demonstrated that ALT could serve as a progestin in cattle and when administered in low doses during early pregnancy could improve pregnancy rates in RPB cows. These results are likely due to a direct effect of P4 on the embryo; however, this mechanism is by means other than binding the PR

A community of learners in an elementary school recorder collegium

Thesis (D.M.A.)--Boston UniversityThe purpose of this study was to explore how students learned in an elementary school Collegium that consisted of SATB recorders. Using Rogoffs Theory of Community of Learners, an examination ofthe experiences of the students, the researcher, parents, classroom teachers, and the principal ofthe school occurred during one academic semester of instruction. The primary question that guided this study was: How did the students, instructor, teachers, and parents work together as a Community of Learners? The research questions for this study included: 1) What were the background conditions that led the students to audition for and take an active role in the Collegium ensemble?; How do the students engage with members ofthe community?; 3) How do the students engage in shared endeavors? Data collection included individual interviews, focus group interviews, journals, observations, and artifacts. Data was coded during the analysis process and revealed the following themes: Foundations ofthe Community uncovered influences from family members, as well as early pre-Collegium experiences; Entry points into the Collegium explored the initial interest by the participants, as they voiced their intentions to be a part ofthe ensemble and spoke oftheir attitudes regarding practice and learning processes; Experiences in the Collegium demonstrated perspectives on rehearsing together, self-preparedness, work attitudes, listening and concentration issues, group awareness, interdependence, learning together, and various issues ofmanaging the ensemble work with other academic commitments. Findings from this study indicated that close interactive behavior developed among the participants within the constructed environment, influenced by several factors, including foundational and educational backgrounds, exposure to the recorders, and an encouragement of a collaborative Community of Learners approach. The study concludes with a consideration ofthe author's role in the community, implications, and need for further study. Implications for the profession include establishing a learning environment that promotes collaborative learning, providing opportunities for students to engage with each other, and using the surrounding community of parents and teachers to assist with teaching students, which can lead to an improvement in the level of performance skills in an ensemble

The Materiality of Early Literacy Curriculum: A Network Case Study of one Kindergarten Classroom in New York City

This dissertation draws on data from a six-month study of the materiality of one Kindergarten classroom undergoing curriculum reform in an urban public elementary school. Informed by a network case study approach, whereby case study methods are uncased through an Actor Network Theory lens, I question what it means to say literacy curriculum is enacted, or reformed, by acknowledging the multiplicity of actors entangled within curriculum, both human and non-human, local and distant, invited and uninvited. Furthermore, I propose ways of uncasing studies of literacy curriculum, revealing how no site—a school, a classroom, or an instructional block—is a fixed case but rather is constructed through networks of mobility streaming from many places. Through ecological surveys, images, fieldnotes, recordings and document archives, I trace the materialities of one Kindergarten classroom outward to reveal multiple dynamic networks—shifting school zones, neighborhoods, and curricular trends—that mobilize various bodies and materials into one seemingly stable public-school classroom. Networked within one morning meeting, for instance, were rotting pumpkins, pocket charts and cheese sandwiches doing the work of environmental nonprofits, DOE officials, and cafeteria staff, all entangled with the teacher and students in solving the problem of food waste at lunch. However, I also confront ethical choices made in tracing literacy curriculum as material “network effects.” Set in the nation’s most segregated school system, I address how curriculum is not only affected by networks of circulating materials, but also networks circulating students’ bodies into unequal school spaces, leading to neighborhood gentrification and changing school funding and enrollment. I conclude with what responsibilities exist for researchers advocating for a material focus to address systemic issues of injustice in schools

Identifying Domain Adjacent Instances for Semantic Parsers

When the semantics of a sentence are not representable in a semantic parser's output schema, parsing will inevitably fail. Detection of these instances is commonly treated as an out-of-domain classification problem. However, there is also a more subtle scenario in which the test data is drawn from the same domain. In addition to formalizing this problem of domain-adjacency, we present a comparison of various baselines that could be used to solve it. We also propose a new simple sentence representation that emphasizes words which are unexpected. This approach improves the performance of a downstream semantic parser run on in-domain and domain-adjacent instances.Comment: EMNLP 2018 Camera Read

SOME ASPECTS OF PAYMENT BY NEGOTIABLE INSTRUMENT: A COMPARATIVE STUDY

The scenes are laid in London, New York, Berlin, and Paris. The plot begins with a debtor\u27s giving his creditor a negotiable instrument in payment of the debt. Complications are introduced when the creditor fails to perfect his rights on the instrument, and yet, naturally enough, wishes to collect his debt. Initially both debtor and creditor are satisfied when the negotiable instrument is given in payment. If it is a time instrument, the debtor has obtained an extension of credit. The creditor, on the other hand, has placed his claim in liquid form; he may realize upon it by discounting the instrument. The Anglo-American, German, and French legal systems, in their own way, attempt to safeguard both the interests of the debtor and the creditor

Cypria petenensis, a new name for the Ostracod Cypria pelagica Brehm 1932

Recently during the preparation of a comprehensive account of the lake plankton (Hutchinson, in press) a rather unfortunate case of homonymy was discovered in the genus Cypria

Purification of Bacillus subtilis aspartate transcarbamylase expressed in Escherichia coli (TB2/pLS2000)

Thesis (B.S.) in Biochemistry--University of Illinois at Urbana-Champaign, 1990.Includes bibliographical references (leaf 36)Microfiche of typescript. [Urbana, Ill.]: Photographic Services, University of Illinois, U of I Library, [1990]. 2 microfiches (43 frames): negative.s 1990 ilu n

New developments in probing and targeting protein acylation in malaria, leishmaniasis and African sleeping sickness

Infections by protozoan parasites, such as Plasmodium falciparum or Leishmania donovani, have a significant health, social and economic impact and threaten billions of people living in tropical and sub-tropical regions of developing countries worldwide. The increasing range of parasite strains resistant to frontline therapeutics makes the identification of novel drug targets and the development of corresponding inhibitors vital. Post-translational modifications (PTMs) are important modulators of biology and inhibition of protein lipidation has emerged as a promising therapeutic strategy for treatment of parasitic diseases. In this review we summarize the latest insights into protein lipidation in protozoan parasites. We discuss how recent chemical proteomic approaches have delivered the first global overviews of protein lipidation in these organisms, contributing to our understanding of the role of this PTM in critical metabolic and cellular functions. Additionally, we highlight the development of new small molecule inhibitors to target parasite acyl transferases

Parametric and Mechanistic Studies of Biomass Conversion to High-Purity Hydrogen with Integrated Carbon Fixation

Due to the increasingly detrimental impacts of the global fossil fuel-driven energy economy, technological solutions that can mitigate the deleterious emissions from fossil fuel conversion or that can lessen societal dependence on fossil fuels are urgently required. The conversion of biomass, a renewable energy feedstock, into energy and fuels that are fungible with those derived from fossil fuels would help supplant some of the global fossil fuel consumption with sustainable energy generation. However, one of the main disadvantages of biomass as an energy feedstock when compared to fossil fuels is its low energy density. The majority of thermochemical biomass conversion technologies therefore focus on converting a low energy density feedstock in biomass to a higher energy density end product. Due to the operating parameters involved in these processes, they are typically accomplished on larger and more centralized scales by skilled operators. Few technologies exist that utilize biomass in a sustainable manner under a distributed energy framework, which would allow energy consumers to use locally available resources and waste material to generate energy. The alkaline thermal treatment of biomass has recently been proposed as a novel method for producing high purity H₂ with suppressed COₓ formation under moderate reaction conditions (i.e., 573 K and ambient pressure). Essentially, biomass, which in this study were the model compounds of glucose and cellulose, is reacted with an alkali metal hydroxide, such as NaOH, in such a molar proportion that all of the carbon and oxygen embodied in the reactants is fixed as an alkali metal carbonate, while all of the elemental hydrogen is released as pure H₂ gas. Thus, fuel cell ready H₂ can be produced from biomass in a single reactor. This technology has great potential for sustainable bioenergy production since it can handle a wide range of feedstocks including biomass and biogenic wastes with high water content. In addition to having the potential to be a distributed energy generation technology, the alkaline thermal treatment of biomass could help meet increasing industrial demand for H₂ in a more sustainable manner, as 96% of current H₂ generation is derived from fossil fuels. The alkaline thermal treatment technology is also relatively unexplored; thus, the effects of parameters such as feedstock type, reaction temperature, heating rate, NaOH:Biomass ratio, method of reactant mixing, flow of steam, and concentration of steam flow, on the gaseous and solid products formed are not fully understood. This study was undertaken to quantify the effects of these non-catalytic variables on the alkaline thermal treatment reaction and to elucidate potential reaction pathways in order to better evaluate the potential of the alkaline thermal treatment technology as a viable biomass conversion technology. In the study of the alkaline thermal treatment of glucose, NaOH did play an important role in suppressing COₓ formation while facilitating H₂ production and promoting CH₄ formation. The non-catalytic alkaline thermal treatment of glucose in the absence of steam flow resulted in a maximum H₂ conversion of about 27% at 523 K with a stoichiometric mixture of NaOH and glucose. The solids analysis confirmed the presence of Na₂CO₃ in the solid product, indicating the inherent carbon management potential of the alkaline thermal treatment process. The addition of steam flow increased conversion to H₂ from 25% to 33%, while decreasing total CH₄ formation 5 fold. After the investigation of the alkaline thermal treatment applied to glucose, cellulose was studied as a feedstock because it is the predominant component of lignocellulosic biomass, the target feedstock source for second generation biofuels. Like in the glucose study, it was found that H₂ and hydrocarbon formation occurred with the addition of NaOH to cellulose under thermal treatment, while the further addition of steam enhanced H₂ production and suppressed hydrocarbon formation. Both the enhancement of H₂ conversion and the suppression of hydrocarbon formation with the addition of steam flow was found to be more significant for cellulose than it was for glucose, with in the cellulose case H₂ conversion doubling from 25% to 48%, and CH₄ formation falling 35 times from the no steam flow case. Also like the glucose study, much of the carbon and oxygen present in the reactants were converted to Na₂CO₃. With the knowledge gained about the effects various reaction parameters had on the alkaline thermal treatment reaction, a study of the reaction pathways of the alkaline thermal treatment of cellulose reaction was undertaken. Compounds formed at intermediate temperatures were identified, tested for gaseous production when reacted with NaOH, and the gas product formation rate trends of these reactions were compared with those trends observed from the alkaline thermal treatment of cellulose reaction. The intermediates identified included sodium carboxylate salts, namely sodium formate, sodium glycolate, and sodium acetate, among others. The reactions of these compounds with NaOH were found to yield H₂ and CH₄, with the gaseous formation rate trends being similar to trends observed for the alkaline thermal treatment reaction for cellulose in certain temperature regions. Particular focus was placed on sodium glycolate, which was an intermediate found in high concentration and that reacted with NaOH to produce both H₂ and CH₄. The formation of Na₂CO₃ at intermediate temperatures was also studied, and the comparison of Na₂CO₃ conversion to H₂ conversion at intermediate temperatures revealed that H₂ and Na₂CO₃ formation do not always occur at the 2:1 H₂:Na₂CO₃ molar ratio implied by the proposed stoichiometry of the alkaline thermal treatment reaction for cellulose. The aforementioned studies were conducted both in the presence and absence of steam flow to study its influence on the reaction. Finally H₂ formation kinetic studies were performed on the alkaline thermal treatment of cellulose system as well as the H₂-producing sodium carboxylate salt reaction systems. Sodium formate and sodium oxalate were found to have better selectivity toward H₂ formation and their reactions were more kinetically favored than sodium glycolate with NaOH. A comparison of the isothermal H₂ kinetics between the cellulose and sodium glycolate systems at higher temperatures, however, revealed that H₂ conversion in the alkaline thermal treatment of cellulose appeared to be limited by the rate of conversion of sodium glycolate. From the results of these studies, recommendations are made for future research directions aimed at improving the alkaline thermal treatment of cellulose reaction