AP STEM Course-taking and College STEM Major Selection: An Examination of the Relationship and How It Differs by Gender and Race/Ethnicity

The United States must expand the STEM pipeline in order to meet the growing demand of the STEM workforce and maintain our nation’s prosperity and competitiveness in the global economy. The urgency of this need has been proclaimed by policymakers, business leaders, politicians, and educators. Despite the growing demand for STEM professionals, women and minorities are an underutilized source of intellectual capital that can and should be tapped into to meet the demand. Doing so creates equity across genders and racial/ethnic groups as well as fosters inclusion of more diverse perspectives to enhance STEM innovations. Efforts to expand the number and diversity of those in STEM fields need to start early on in students’ academic careers. The purpose of this study was to examine the relationship between Advanced Placement (AP) STEM course-taking in high school and selection of college STEM major and to determine whether the relationship differs across racial/ethnic groups and male and female students. This study was designed to help educators and policymakers shape college preparation programs and policies as well as to counsel students during their course selection process in high school. A two-level logistic regression model with fixed effects was utilized to determine the relationship between AP STEM course-taking and STEM major selection, controlling for all relevant student-level and school-level variables. Missing data was accounted for through multiple imputations. Sensitivity testing was also conducted to examine whether exposure to AP STEM courses versus number of AP STEM courses matters in the model explaining STEM major selection. Lastly, the analysis also included a series of interaction effects tests, examining the variation of gender and racial/ethnic differences in STEM major selection as a function of AP STEM course-taking. The sample for this study is taken from the High School Longitudinal Study of 2009 and includes students who were high school freshmen in fall 2009. Data was collected on these students during fall of their freshman year of high school in 2009, during the spring of 11th grade in 2012, and in the spring of 2016, three years after the majority graduated from high school. Findings indicate that gender, STEM course credits, AP STEM course exposure, math self-efficacy, science self-efficacy, aspiring to a graduate degree or higher, and math SAT score are all significant predictors of STEM major selection. Additionally, the results of the interaction effects test using logistic regression show that the relationship between AP STEM course-taking and STEM major selection varies significantly by gender. More specifically, exposure to AP STEM courses increases the odds of female students selecting a STEM major more significantly than for male students

AP STEM Course-taking and College STEM Major Selection: An Examination of the Relationship and How It Differs by Gender and Race/Ethnicity

The United States must expand the STEM pipeline in order to meet the growing demand of the STEM workforce and maintain our nation’s prosperity and competitiveness in the global economy. The urgency of this need has been proclaimed by policymakers, business leaders, politicians, and educators. Despite the growing demand for STEM professionals, women and minorities are an underutilized source of intellectual capital that can and should be tapped into to meet the demand. Doing so creates equity across genders and racial/ethnic groups as well as fosters inclusion of more diverse perspectives to enhance STEM innovations. Efforts to expand the number and diversity of those in STEM fields need to start early on in students’ academic careers. The purpose of this study was to examine the relationship between Advanced Placement (AP) STEM course-taking in high school and selection of college STEM major and to determine whether the relationship differs across racial/ethnic groups and male and female students. This study was designed to help educators and policymakers shape college preparation programs and policies as well as to counsel students during their course selection process in high school. A two-level logistic regression model with fixed effects was utilized to determine the relationship between AP STEM course-taking and STEM major selection, controlling for all relevant student-level and school-level variables. Missing data was accounted for through multiple imputations. Sensitivity testing was also conducted to examine whether exposure to AP STEM courses versus number of AP STEM courses matters in the model explaining STEM major selection. Lastly, the analysis also included a series of interaction effects tests, examining the variation of gender and racial/ethnic differences in STEM major selection as a function of AP STEM course-taking. The sample for this study is taken from the High School Longitudinal Study of 2009 and includes students who were high school freshmen in fall 2009. Data was collected on these students during fall of their freshman year of high school in 2009, during the spring of 11th grade in 2012, and in the spring of 2016, three years after the majority graduated from high school. Findings indicate that gender, STEM course credits, AP STEM course exposure, math self-efficacy, science self-efficacy, aspiring to a graduate degree or higher, and math SAT score are all significant predictors of STEM major selection. Additionally, the results of the interaction effects test using logistic regression show that the relationship between AP STEM course-taking and STEM major selection varies significantly by gender. More specifically, exposure to AP STEM courses increases the odds of female students selecting a STEM major more significantly than for male students

Food of the Pacific cod Gadus macrocephalus Tilesius near Kodiak Island, Alaska

Thesis (M.S.) University of Alaska Fairbanks, 1977The Pacific cod, Gadus macroaephalus, from the Kodiak Alaska continental shelf, feeds predominantly on demersal fishes and crustaceans. The most frequently occurring food groups in Pacific cod stomachs in order of decreasing frequency of occurrence are fishes, crabs, shrimps and amphipods. The snow crab, Chionoecetes bairdi, is the most frequently occurring food species. Frequency occurrence of food items in cod stomachs is enumerated within each of three cod size groups - 33 to 52 cm, 53 to 72 cm, and 73 to 92 cm. Fishes and cephalopods increase in frequency occurrence with increasing cod size. Amphipods and polychaetes are more frequently found in smaller fish. In general, the incidence of euphausiids and mysids decrease with increasing cod size. Crabs, shrimps, pelecypods and gastropods increase in frequency occurrence from the small (33 to 52 cm) to the medium size fish (53 to 72 cm) and again decline in importance among larger cod (73 to 92 cm)

In vitro integration of ribosomal RNA synthesis, ribosome assembly, and translation

Purely in vitro ribosome synthesis could provide a critical step towards unraveling the systems biology of ribosome biogenesis, constructing minimal cells from defined components, and engineering ribosomes with new functions. Here, as an initial step towards this goal, we report a method for constructing Escherichia coli ribosomes in crude S150 E. coli extracts. While conventional methods for E. coli ribosome reconstitution are non-physiological, our approach attempts to mimic chemical conditions in the cytoplasm, thus permitting several biological processes to occur simultaneously. Specifically, our integrated synthesis, assembly, and translation (iSAT) technology enables one-step co-activation of rRNA transcription, assembly of transcribed rRNA with native ribosomal proteins into functional ribosomes, and synthesis of active protein by these ribosomes in the same compartment. We show that iSAT makes possible the in vitro construction of modified ribosomes by introducing a 23S rRNA mutation that mediates resistance against clindamycin. We anticipate that iSAT will aid studies of ribosome assembly and open new avenues for making ribosomes with altered properties

Mollusks in the Northeastern Chukchi Sea

Infaunal and epifaunal mollusks of the northeastern Chukchi Sea were sampled and 139 molluscan taxa were identified. The pattern of spatial distribution of molluscan species was determined by cluster analysis, which resulted in six infaunal and five epifaunal station groups. Species characterizing various faunal groups are defined. Stepwise multiple discriminant analysis was applied to correlate benthic biological associations with environmental variables. Delineation of infaunal groups was mainly due to percentage of sand and bottom salinity, while epifaunal groups were separated by percent gravel and bottom temperature. An increase in abundance and biomass of infaunal mollusks occurred adjacent to and north and northwest of an identified bottom front between the Bering Shelf and Resident Chukchi Water and Alaska Coastal Water. Epifaunal molluscan abundance and biomass were highest near the coast. Mollusks, especially smaller species and the juvenile stages of larger species, represent a food resource for bottom-feeding predators in the study area.Key words: Chukchi Sea, mollusk, benthic, infauna, epifauna, bottom front, bottom-feeding predators, cluster analysis, discriminant analysisOn a fait un échantillonnage des mollusques de l'endofaune et de l'épifaune du nord-est de la mer des Tchouktches et on a identifié 139 taxons de mollusques. On a déterminé le schéma de répartition géographique des espèces de mollusques au moyen d'une analyse typologique, qui a donné six groupes de stations dans l'endofaune et cinq dans l'épifaune. On définit des espèces caractéristiques des divers groupes fauniques. On a appliqué une analyse discriminante multiple séquentielle pour corréler les associations biologiques du benthos aux variables de l'environnement. La délimitation des groupes de l'endofaune était due en grande partie au taux de sable et de salinité au fond, tandis que les groupes de l'épifaune étaient répartis en fonction du taux de gravier et de température au fond. Une augmentation dans la quantité et la biomasse des mollusques de l'endofaune apparaissait près du nord et du nord-ouest d'un front de fond compris entre le plateau continental, les eaux non brassées de la mer des Tchouktches et les eaux côtières de l'Alaska. C'est près de la côte qu'on retrouvait l'abondance et la biomasse maximales des mollusques de l'épifaune. Les mollusques, surtout ceux des petites espèces et ceux des grandes espèces qui étaient au stade juvénile, représentaient une source alimentaire pour les prédateurs benthiques vivant dans la zone d'étude.Mots clés : mer des Tchouktches, mollusque, benthique, enfofaune, épifaune, front au fond, prédateurs benthiques, analyse typologique, analyse discriminant

An integrated cell-free metabolic platform for protein production and synthetic biology

Cell-free systems offer a unique platform for expanding the capabilities of natural biological systems for useful purposes, i.e. synthetic biology. They reduce complexity, remove structural barriers, and do not require the maintenance of cell viability. Cell-free systems, however, have been limited by their inability to co-activate multiple biochemical networks in a single integrated platform. Here, we report the assessment of biochemical reactions in an Escherichia coli cell-free platform designed to activate natural metabolism, the Cytomim system. We reveal that central catabolism, oxidative phosphorylation, and protein synthesis can be co-activated in a single reaction system. Never before have these complex systems been shown to be simultaneously activated without living cells. The Cytomim system therefore promises to provide the metabolic foundation for diverse ab initio cell-free synthetic biology projects. In addition, we describe an improved Cytomim system with enhanced protein synthesis yields (up to 1200 mg/l in 2 h) and lower costs to facilitate production of protein therapeutics and biochemicals that are difficult to make in vivo because of their toxicity, complexity, or unusual cofactor requirements

Biology by Design: From Top to Bottom and Back

Synthetic biology is a nascent technical discipline that seeks to enable the design and construction of novel biological systems to meet pressing societal needs. However, engineering biology still requires much trial and error because we lack effective approaches for connecting basic “parts” into higher-order networks that behave as predicted. Developing strategies for improving the performance and sophistication of our designs is informed by two overarching perspectives: “bottom-up” and “top-down” considerations. Using this framework, we describe a conceptual model for developing novel biological systems that function and interact with existing biological components in a predictable fashion. We discuss this model in the context of three topical areas: biochemical transformations, cellular devices and therapeutics, and approaches that expand the chemistry of life. Ten years after the construction of synthetic biology's first devices, the drive to look beyond what does exist to what can exist is ushering in an era of biology by design

An integrated cell-free metabolic platform for protein production and synthetic biology

Cell-free systems offer a unique platform for expanding the capabilities of natural biological systems for useful purposes, i.e. synthetic biology. They reduce complexity, remove structural barriers, and do not require the maintenance of cell viability. Cell-free systems, however, have been limited by their inability to co-activate multiple biochemical networks in a single integrated platform. Here, we report the assessment of biochemical reactions in an Escherichia coli cell-free platform designed to activate natural metabolism, the Cytomim system. We reveal that central catabolism, oxidative phosphorylation, and protein synthesis can be co-activated in a single reaction system. Never before have these complex systems been shown to be simultaneously activated without living cells. The Cytomim system therefore promises to provide the metabolic foundation for diverse ab initio cell-free synthetic biology projects. In addition, we describe an improved Cytomim system with enhanced protein synthesis yields (up to 1200 mg/l in 2 h) and lower costs to facilitate production of protein therapeutics and biochemicals that are difficult to make in vivo because of their toxicity, complexity, or unusual cofactor requirements

The genome-scale metabolic model iIN800 of Saccharomyces cerevisiae and its validation: a scaffold to query lipid metabolism

Background: Up to now, there have been three published versions of a yeast genome-scale metabolic model: iFF708, iND750 and iLL672. All three models, however, lack a detailed description of lipid metabolism and thus are unable to be used as integrated scaffolds for gaining insights into lipid metabolism from multilevel omic measurement technologies (e.g. genome-wide mRNA levels). To overcome this limitation, we reconstructed a new version of the Saccharomyces cerevisiae genome-scale model, ilN800 that includes a more rigorous and detailed descrition of lipid metabolism. Results: The reconstructed metabolic model comprises 1446 reactions and 1013 metabolites. Beyond incorporating new reactions involved in lipid metabolism, we also present new biomass equations that improve the predictive power of flux balance analysis simulations. Predictions of both growth capability and large scale in silico single gene deletions by ilN800 were consistent with experimental data. In addition, 13C-labeling experiments validated the new biomass equations and calculated intracellular fluxes. To demonstrate the applicability of ilN800, we show that the model can be used as a scaffold to reveal the regulatory importance of lipid metabolism precursors and intermediates that would have been missed in previous models from transcriptome datasets. Conclusions: Performing integrated analyses using ilN800 as a network scaffold is shown to be a valuable tool for elucidating the behavior of complex metabolic networks, particularly for identifying regulatory targets in lipid metabolism that can be used for industrial applications or for understanding lipid disease states

Self-assembly of temperature-responsive protein–polymer bioconjugates

We report a simple temperature-responsive bioconjugate system comprising superfolder green fluorescent protein (sfGFP) decorated with poly[(oligo ethylene glycol) methyl ether methacrylate] (PEGMA) polymers. We used amber suppression to site-specifically incorporate the non-canonical azide-functional amino acid p-azidophenylalanine (pAzF) into sfGFP at different positions. The azide moiety on modified sfGFP was then coupled using copper-catalyzed “click” chemistry with the alkyne terminus of a PEGMA synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. The protein in the resulting bioconjugate was found to remain functionally active (i.e., fluorescent) after conjugation. Turbidity measurements revealed that the point of attachment of the polymer onto the protein scaffold has an impact on the thermoresponsive behavior of the resultant bioconjugate. Furthermore, small-angle X-ray scattering analysis showed the wrapping of the polymer around the protein in a temperature-dependent fashion. Our work demonstrates that standard genetic manipulation combined with an expanded genetic code provides an easy way to construct functional hybrid biomaterials where the location of the conjugation site on the protein plays an important role in determining material properties. We anticipate that our approach could be generalized for the synthesis of complex functional materials with precisely defined domain orientation, connectivity, and composition