The Contract for College

Rising college costs, combined with major policy changes in financial aid, have made college less affordable for today's generation of young people. The Contract for College would unify the existing three strands of federal financial aid--grants, loans and work-study--into a coherent, guaranteed financial aid package for students

Exploration and Statistical Modeling of Profit

For any company involved in sales, maximization of profit is the driving force that guides all decision-making. Many factors can influence how profitable a company can be, including external factors like changes in inflation or consumer demand or internal factors like pricing and product cost. Understanding specific trends in one\u27s own internal data, a company can readily identify problem areas or potential growth opportunities to help increase profitability. In this discussion, we use an extensive data set to examine how a company might analyze their own data to identify potential changes the company might investigate to drive better performance. Based upon general trends in the data, we recommend potential actions the company could take. Additionally, we examine how a company can utilize predictive modeling to help them adapt their decision-making process as the trends identified from the initial analysis of the data evolve over time

Applications of Chemical Methodology in Environmental Science, Systems Biology, and Interdisciplinary Chemical Education

Chapter Two Abstract The environmental impacts of hydraulic fracturing, particularly those of surface spills in aquatic ecosystems, are not fully understood. The goals of this study were to: (1) understand the effect of previous exposure to hydraulic fracturing fluids on aquatic microbial community structure and (2) examine the impacts exposure has on biodegradation potential of the biocide glutaraldehyde. Microcosms were constructed from hydraulic fracturing-impacted and non-hydraulic fracturing-impacted stream water within the Marcellus shale region in Pennsylvania. Microcosms were amended with glutaraldehyde and incubated aerobically for 56 days. Microbial community adaptation to glutaraldehyde was monitored using 16S rRNA gene amplicon sequencing and quantification by qPCR. Abiotic and biotic glutaraldehyde degradation was measured using ultra performance liquid chromatography—mass spectrometry and total organic carbon. It was found that non-hydraulic fracturing-impacted microcosms biodegraded glutaraldehyde faster than the hydraulic fracturing-impacted microcosms, showing a decrease in degradation potential after exposure to hydraulic fracturing activity. Hydraulic fracturing impacted microcosms showed higher richness after glutaraldehyde exposure compared to non-impacted streams, indicating an increased tolerance to glutaraldehyde in hydraulic fracturing impacted streams. Beta diversity and differential abundance analysis of sequence count data showed different bacterial enrichment for hydraulic fracturing-impacted and non-hydraulic fracturing-impacted microcosms after glutaraldehyde addition. These findings demonstrated a lasting effect on microbial community structure and glutaraldehyde degradation potential in streams impacted by hydraulic fracturing operations. Chapter Three Abstract Adaptive thermogenesis has re-emerged as an important component of energy expenditure. N-acyl amino acids (N-AAAs) can contribute to adaptive thermogenesis by uncoupling mitochondrial respiration. Hypothesizing that lipolysis promotes the formation of N-AAAs, the connection was studied in an avian model (chickens) because lipolysis is readily induced by acute (~ 4 hr) food withdrawal. An avian model also allowed evaluation of N-AAA production in the absence of brown adipose tissue, which was reported to contribute the enzyme (peptidase M20 domain containing 1 (PM20D1)) that catalyzes their synthesis. Serum samples were collected from 21 d broiler chicks that were fed ad libitum, fasted for 4, 8, or 12 h, or fasted for 12 h and then re-fed for 2 h (n=10/group). Samples were profiled for levels of 27 N-AAA species using a novel UPLC-HRMS method. In short, a single Ultra-Performance Liquid Chromatography—High Resolution Mass Spectrometry (UPLC-HRMS) method was developed and validated with 27 N-acyl amino acid standards and 20 bile acid standards. (Given their shared relevance for obesity research and their similar physio-chemical properties, a single analytical method for the simultaneous detection of these metabolites is desirable). Reversed-phase chromatography and Orbitrap mass spectrometry were used in tandem to detect the 47 metabolites in a 20.5-minute method. The standards were detected with a high degree of mass accuracy (less than 2 ppm for all N-AAAs and less than 7 ppm for all bile acids). In addition, protocols for the extraction of these metabolites from biological media were tested. Fasting progressively increased the serum pool of N-AAAs (p=1.8-06), in parallel with increased non-esterified fatty acid (NEFA) levels (p=0.0003). Refeeding for 2 h rapidly restored the N-AAA pool to fed levels (p=0.99; fed vs. 12 h fast-refed). Percent abundance of some species (e.g., oleoyl-l-valine; p=2.8-04) increased with fasting while others (e.g., stearoyl-l-leucine; p=1.9-05) declined, suggesting molecule-specific regulation of N-AAA synthesis. Expression of PM20D1 in adipose tissue (subcutaneous and abdominal) and in liver was not affected by fasting. Effect of diet on N-AAA expression was also evaluated using the same boiler chick model. Four unique diets, containing a supplement of flaxseed, canola, fish, or animal (lard) oil were administered to chicks, which were then sacrificed for analysis of N-AAA in tissue. The fatty acid composition of each diet was 42 directly reflected in the tail composition of each N-AAA profile. This suggests that substrate availability may be a prominent means of N-AAA regulation. Chapter Four Abstract ZorO (Z-protein often repeated) is a small protein expressed by pathogenic enterohemorrhagic Escherichia coli (EHEC E. coli) which was recently discovered through bioinformatic searches. While its biological role is still being elucidated, it has been demonstrated to exhibit toxic effects on the cell when overproduced. This puzzling genetic ability for what, at first glance, appears to be self-destruction may be nuanced way for wild strains of bacteria to adapt to host environments or survive stress. This likely entails a much more minimal expression of ZorO, initiating subtle cell behavior that is less apocalyptic. In order to investigate the localization and function of endogenously expressed ZorO, the protein was be synthesized for biophysical experimentation using solid-phase peptide synthesis. In addition, several analogs of ZorO were synthesized to further enable an investigation of structure-activity relationship. These analogs include versions of ZorO with single amino acid mutations, as well as variants with “tags” for detection, purification, or capturing transient interactions. In the latter case, an unnatural replacement of the amino acid methionine (photo-methionine) was synthesized for incorporation into a synthetic peptide analog. This synthesis work required exploration of literature and reaction optimization, ultimately leading to a novel synthesis of photomethionine. Much of the synthetic groundwork for studying ZorO has now been laid, and efforts are underway to develop analytical methods for detecting ZorO in cell extracts—a daunting task considering the complex protein composition of the cell and the wide concentration ranges spanned by endogenously-expressed polypeptides

Designing and Evaluating the Quality and Cost-effectiveness of Saturated Sediment Permeameters

Many simulations require accurate measurements of saturated hydraulic conductivity, a sediment property that governs the speed at which water flows through sediments relative to head differences. The goal of our project is to design and build an inexpensive permeameter capable of producing accurate hydraulic conductivity values. We tested four permeameters; a standard research grade constant-head permeameter, a falling-head permeameter modeled off of an in situ stream method, a constant-head permeameter made out of 4” PVC pipe, and a similar constant-head permeameter made out of 2” PVC pipe. Our custom-built constant-head permeameters both utilized a U-shaped design, two tubes which form a manometer, and multiple output overflows. Despite significant differences in design, method, and cost, we found that all four of the permeameters yielded relatively consistent mean hydraulic conductivities with low standard deviations (0.004-0.019). We also compared the attributes: price, weight, and number of parts. Our conclusion is that because the average K-value and standard deviation of each design is within reason, the best choice depends on the practitioner’s situation and intention.Faculty Sponsor: Susa H. Stonedah

Designing and Evaluating the Quality and Cost-effectiveness of Saturated Sediment Permeameters

Many simulations require accurate measurements of saturated hydraulic conductivity, a sediment property that governs the speed at which water flows through sediments relative to head differences. The goal of our project is to design and build an inexpensive permeameter capable of producing accurate hydraulic conductivity values. We tested four permeameters; a standard research grade constant-head permeameter, a falling-head permeameter modeled off of an in situ stream method, a constant-head permeameter made out of 4” PVC pipe, and a similar constant-head permeameter made out of 2” PVC pipe. Our custom-built constant-head permeameters both utilized a U-shaped design, two tubes which form a manometer, and multiple output overflows. Despite significant differences in design, method, and cost, we found that all four of the permeameters yielded relatively consistent mean hydraulic conductivities with low standard deviations (0.004-0.019). We also compared the attributes: price, weight, and number of parts. Our conclusion is that because the average K-value and standard deviation of each design is within reason, the best choice depends on the practitioner’s situation and intention

Prevalence and impacts of ants colonizing active bird nests in Illinois

Arthropod communities are often dependent on the availability of ephemeral microhabitats. Many organisms, including birds, mammals and social insects, build nests which create unique and suitable microhabitats for a variety of other animals. These constructed environments can protect their residents from predation and from harmful abiotic conditions. In turn, the communities of arthropods that colonize animal made habitats may positively or negatively influence the nest owner. Bird nests, for example, are known to harbor arthropods communities that include both harmful (e.g. ectoparasitic fly larvae) and possibly beneficial species. I quantified the arthropod communities of nests of ten species of birds in Illinois along a land-use gradient. I found workers of eight species of ants in nests, and for three of these species (Tapinoma sessile, Temnothorax curvispinosus, and Crematogaster cerasi) there was evidence that at least part of their colonies inhabited the nest. Tapioma sessile was the most common species and maintained the largest colonies in nest material. I found that the percentage of forest cover surrounding bird nests best predicted the presence of T. sessile colonies, with colonies being negatively associated with forest cover. In addition to ants, members of 19 other arthropod orders were found living in the nests. There was little evidence that ant presence influenced the abundance or prevalence of other arthropods within nests with one exception. Brown Thrasher nests with T. sessile colonies had fewer fly larvae and pupae than nests without ants. Fledging success did not differ between nests with and without T. sessile colonies for any bird species. Polydomy and a high degree of nomadism are characteristics which likely predispose ant species like T. sessile to colonizing active bird nests. The association between these ant species and bird nests likely is a facultative commensalism benefiting ants that is widespread in North America, and warrants further investigation

Graduate Recital: Caleb Gibson, Saxophone; Lu Witzig, Piano; Ryan Baur, Saxophone; Baryl Brandt, Marimba; April 19, 2022

Kemp Recital Hall April 19, 2022 Tuesday Evening 8:00 p.m

The HST Key Project on the Extragalactic Distance Scale XXV. A Recalibration of Cepheid Distances to Type Ia Supernovae and the Value of the Hubble Constant

Cepheid-based distances to seven Type Ia supernovae (SNe)-host galaxies have been derived using the standard HST Key Project on the Extragalactic Distance Scale pipeline. For the first time, this allows for a transparent comparison of data accumulated as part of three different HST projects, the Key Project, the Sandage et al. Type Ia SNe program, and the Tanvir et al. Leo I Group study. Re-analyzing the Tanvir et al. galaxy and six Sandage et al. galaxies we find a mean (weighted) offset in true distance moduli of 0.12+/-0.07 mag -- i.e., 6% in linear distance -- in the sense of reducing the distance scale, or increasing H0. Adopting the reddening-corrected Hubble relations of Suntzeff et al. (1999), tied to a zero point based upon SNe~1990N, 1981B, 1998bu, 1989B, 1972E and 1960F and the photometric calibration of Hill et al. (1998), leads to a Hubble constant of H0=68+/-2(random)+/-5(systematic) km/s/Mpc. Adopting the Kennicutt et al. (1998) Cepheid period-luminosity-metallicity dependency decreases the inferred H0 by 4%. The H0 result from Type Ia SNe is now in good agreement, to within their respective uncertainties, with that from the Tully-Fisher and surface brightness fluctuation relations.Comment: Accepted for publication in The Astrophysical Journal. 62 pages, LaTeX, 9 Postscript figures. Also available at http://casa.colorado.edu/~bgibson/publications.htm

Allophycocyanin A is a carbon dioxide receptor in the cyanobacterial phycobilisome

Light harvesting is fundamental for production of ATP and reducing equivalents for CO2 fixation during photosynthesis. However, electronic energy transfer (EET) through a photosystem can harm the photosynthetic apparatus when not balanced with CO2. Here, we show that CO2 binding to the light-harvesting complex modulates EET in photosynthetic cyanobacteria. More specifically, CO2 binding to the allophycocyanin alpha subunit of the light-harvesting complex regulates EET and its fluorescence quantum yield in the cyanobacterium Synechocystis sp. PCC 6803. CO2 binding decreases the inter-chromophore distance in the allophycocyanin trimer. The result is enhanced EET in vitro and in live cells. Our work identifies a direct target for CO2 in the cyanobacterial light-harvesting apparatus and provides insights into photosynthesis regulation