Three essays on poverty, income shocks, and decision-making: Evidence from Malawi and Zambia

This dissertation contributes to the literature on decision-making under poverty by empirically examining the relationship between income poverty and the decisions that households make due to shocks. This dissertation is composed of three essays attempting to identify ways policy can be used to influence the trajectory of poverty for generations to come. Each chapter focuses on gaining a deeper understanding of the decision-making processes of households and individuals living in poverty. In the first essay, I identify the indirect impact of the Malawi Social Cash Transfer Program on youths’ present bias, by examining the intergenerational transmission of such bias within the household from caregivers to youth. The second essay is focused on negative income shocks and marriage outcomes for youth in rural Malawi. The paper utilizes survey data from a cohort of unmarried youth and follows them over three years as they transition into and out of relationships, identifying the influence negative shocks have on these outcomes. In the final essay, I show the impacts of the Malawi Social Cash Transfer Program and the Zambia Child Grant Program on stress and affect, and, subsequently, whether these psychological indicators affect savings and intertemporal choices.Doctor of Philosoph

A case study of the impact of a reformed science curriculum on student attitudes and learning in a secondary physics classroom

This case study examined the impact of the application of an inquiry-based concept related physics curriculum on student attitudes and learning in a secondary physics classroom in southern New Jersey. Students who had previously used a traditional physics curriculum were presented with a 10 week inquiry-based concept related physics curriculum on electricity and magnetism. The study utilized observations, a pre/post attitudinal survey, interviews of students and teachers about their perceptions of the inquiry-based curriculum, and artifact analysis of student work. The results showed a positive change in students‘ attitude in four of the eight categories designated in the CLASS survey. The observations, interviews and artifact analysis revealed that students were more engaged in learning physics through their discoveries in relating physics concepts to real world applications, a growing personal interest in the value and relevance of science learning and a disconnect between the students‘ and teacher‘s perceptions about what is important in learning physics. The study recommends that the rigidity of a traditional physics curriculum with its emphasis on covering many topics and the mathematical language of physics should give way to more inquiry-based concept related curriculum that incorporates exploration, hands-on inquiry activities, and real world connections. The research supports that better efforts be made to familiarize current and future secondary physics educators with the body of research that establishes the benefits of inquiry-based concept related curriculum on physics students.Ph.D., Educational Leadership Development and Learning Technologies -- Drexel University, 201

In vitro synthesis of uniform poly(dG)–poly(dC) by Klenow exo(−) fragment of polymerase I

In this paper, we describe a production procedure of the one-to-one double helical complex of poly(dG)–poly(dC), characterized by a well-defined length (up to 10 kb) and narrow size distribution of molecules. Direct evidence of strands slippage during poly(dG)–poly(dC) synthesis by Klenow exo(−) fragment of polymerase I is obtained by fluorescence resonance energy transfer (FRET). We show that the polymer extension results in an increase in the separation distance between fluorescent dyes attached to 5′ ends of the strands in time and, as a result, losing communication between the dyes via FRET. Analysis of the products of the early steps of the synthesis by high-performance liquid chromatography and mass spectroscopy suggest that only one nucleotide is added to each of the strand composing poly(dG)–poly(dC) in the elementary step of the polymer extension. We show that proper pairing of a base at the 3′ end of the primer strand with a base in sequence of the template strand is required for initiation of the synthesis. If the 3′ end nucleotide in either poly(dG) or poly(dC) strand is substituted for A, the polymer does not grow. Introduction of the T-nucleotide into the complementary strand to permit pairing with A-nucleotide results in the restoration of the synthesis. The data reported here correspond with a slippage model of replication, which includes the formation of loops on the 3′ ends of both strands composing poly(dG)–poly(dC) and their migration over long-molecular distances (μm) to 5′ ends of the strands

Synthesis of novel poly(dG)-poly(dG)-poly(dC) triplex structure by Klenow exo− fragment of DNA polymerase I

The extension of the G-strand of long (700 bp) poly(dG)-poly(dC) by the Klenow exo− fragment of DNA polymerase I yields a complete triplex structure of the H-DNA type. High-performance liquid chromatography analysis demonstrates that the length of the G-strand is doubled during the polymerase synthesis. Fluorescence resonance energy transfer analysis shows that the 5′ ends of the G- and the C-strands, labeled with fluorescein and TAMRA, respectively, are positioned close to each other in the product of the synthesis. Atomic force microscopy morphology imaging shows that the synthesized structures lack single-stranded fragments and have approximately the same length as the parent 700 bp poly(dG)-poly(dC). CD spectrum of the polymer has a large negative peak at 278 nm, which is characteristic of the poly(dG)-poly(dG)-poly(dC) triplex. The polymer is resistant to DNase and interacts much more weakly with ethidium bromide as compared with the double-stranded DN

Synthesis of novel poly(dG)–poly(dG)–poly(dC) triplex structure by Klenow exo(−) fragment of DNA polymerase I

The extension of the G-strand of long (700 bp) poly(dG)–poly(dC) by the Klenow exo(−) fragment of DNA polymerase I yields a complete triplex structure of the H-DNA type. High-performance liquid chromatography analysis demonstrates that the length of the G-strand is doubled during the polymerase synthesis. Fluorescence resonance energy transfer analysis shows that the 5′ ends of the G- and the C-strands, labeled with fluorescein and TAMRA, respectively, are positioned close to each other in the product of the synthesis. Atomic force microscopy morphology imaging shows that the synthesized structures lack single-stranded fragments and have approximately the same length as the parent 700 bp poly(dG)–poly(dC). CD spectrum of the polymer has a large negative peak at 278 nm, which is characteristic of the poly(dG)–poly(dG)–poly(dC) triplex. The polymer is resistant to DNase and interacts much more weakly with ethidium bromide as compared with the double-stranded DNA

Differentially Disrupted Spinal Cord and Muscle Energy Metabolism in Spinal and Bulbar Muscular Atrophy

Prior studies showed that polyglutamine-expanded androgen receptor (AR) is aberrantly acetylated and that deacetylation of the mutant AR by overexpression of nicotinamide adenine dinucleotide-dependent (NAD+-dependent) sirtuin 1 is protective in cell models of spinal and bulbar muscular atrophy (SBMA). Based on these observations and reduced NAD+ in muscles of SBMA mouse models, we tested the therapeutic potential of NAD+ restoration in vivo by treating postsymptomatic transgenic SBMA mice with the NAD+ precursor nicotinamide riboside (NR). NR supplementation failed to alter disease progression and had no effect on increasing NAD+ or ATP content in muscle, despite producing a modest increase of NAD+ in the spinal cords of SBMA mice. Metabolomic and proteomic profiles of SBMA quadriceps muscles indicated alterations in several important energy-related pathways that use NAD+, in addition to the NAD+ salvage pathway, which is critical for NAD+ regeneration for use in cellular energy production. We also observed decreased mRNA levels of nicotinamide riboside kinase 2 (Nmrk2), which encodes a key kinase responsible for NR phosphorylation, allowing its use by the NAD+ salvage pathway. Together, these data suggest a model in which NAD+ levels are significantly decreased in muscles of an SBMA mouse model and intransigent to NR supplementation because of decreased levels of Nmrk2