Designing a Central Resource for Environmental Management in Costa Rica

In order to mitigate climate change, Costa Rica set a national goal to become carbon neutral by 2021. To help achieve this goal, organizations within Costa Rica could become carbon neutral through the use of environmental management systems to improve their sustainability and environmental product declarations to communicate the environmental impacts of products. Using information obtained through research and interviews with large organizations, our project created a central location of information in the form of a website that contains relevant standards, resources, and guidelines to help small and medium-sized organizations move towards carbon neutrality

Ensuring the Safe Production of Natural Gas

Growing demand for natural gas in the U.S. has led to an increase in hydraulic fracturing in the Marcellus Shale region of PA. The goal of this project was to recommend best practices to the U.S. Department of Energy for hydraulic fracturing. First, industry practices for well drilling, cementing, and casing were analyzed. A System-Theoretic Process Analysis was used to identify weaknesses that could lead to loss of wellbore integrity; and a blowout preventer system was designed to mitigate this hazard. Second, contaminants in hydraulic fracturing fluids were identified and a mobile onsite wastewater treatment system using reverse osmosis was designed to remove fracturing chemicals, radium, and solids. Lastly, recommendations were made to improve the safety of natural gas recovery

Retrotransposons Are the Major Contributors to the Expansion of the Drosophila ananassae Muller F Element

The discordance between genome size and the complexity of eukaryotes can partly be attributed to differences in repeat density. The Muller F element (∼5.2 Mb) is the smallest chromosome in Drosophila melanogaster, but it is substantially larger (>18.7 Mb) in D. ananassae. To identify the major contributors to the expansion of the F element and to assess their impact, we improved the genome sequence and annotated the genes in a 1.4-Mb region of the D. ananassae F element, and a 1.7-Mb region from the D element for comparison. We find that transposons (particularly LTR and LINE retrotransposons) are major contributors to this expansion (78.6%), while Wolbachia sequences integrated into the D. ananassae genome are minor contributors (0.02%). Both D. melanogaster and D. ananassae F-element genes exhibit distinct characteristics compared to D-element genes (e.g., larger coding spans, larger introns, more coding exons, and lower codon bias), but these differences are exaggerated in D. ananassae. Compared to D. melanogaster, the codon bias observed in D. ananassae F-element genes can primarily be attributed to mutational biases instead of selection. The 5′ ends of F-element genes in both species are enriched in dimethylation of lysine 4 on histone 3 (H3K4me2), while the coding spans are enriched in H3K9me2. Despite differences in repeat density and gene characteristics, D. ananassae F-element genes show a similar range of expression levels compared to genes in euchromatic domains. This study improves our understanding of how transposons can affect genome size and how genes can function within highly repetitive domains