Muhlenberg College is a private liberal arts college located in Allentown, Pennsylvania, United States. Founded in 1848, Muhlenberg is affiliated with the Evangelical Lutheran Church in America and is named for Henry Melchior Muhlenberg, the German patriarch of the Lutheran Church in America. Wikipedia.
Clark A.B.,Muhlenberg College
Journal of High Energy Physics | Year: 2014
This paper shows that the positive-energy and non-renormalization theorems of traditional supersymmetry survive the addition of Lorentz violating interactions. The Lorentz-violating coupling constants in theories using the construction of Berger and Kostelecky must obey certain constraints in order to preserve the positive energy theorem. Seiberg's holomorphic arguments are used to prove that the superpotential remains non-renormalized (perturbatively) in the presence of Lorentz-violating interactions of the Berger-Kostelecky type. We briefly comment on Lorentz-violating theories of the type constructed by Nibbelink and Pospelov to note that holomorphy arguments offer elegant proofs of many non-renormalization results, some known by other arguments, some new. © 2014 The Author(s).
Colabroy K.L.,Muhlenberg College
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2016
The metabolic pathways for the production of lincomycin, hormaomycin and the antitumor pyrrolo [1,4] benzodiazepines share a vinyl substituted pyrroline carboxylic acid (3-vinyl-2,3-pyrroline-5-carboxylic acid, VPCA) as a common intermediate. Biosynthesis of this vinyl substituted pyrroline carboxylic acid intermediate requires a short, three-enzyme pathway containing two metalloenzymes: a heme-dependent l-tyrosine hydroxylase and a non-heme Fe2+ dependent l-DOPA dioxygenase. The l-tyrosine hydroxylase is an unprecedented type of peroxidase that specifically monohydroxylates tyrosine, while the l-DOPA extradiol cleaving enzyme is a single-domain vicinal-oxygen-chelate (VOC) dioxygenase. The dioxygenase product subsequently undergoes an, as yet uncharacterized, C-C bond cleavage reaction. This mini-pathway demonstrates the use of metal-dependent chemistry typically associated with natural product degradation in order to build a compact, functionalized building block for larger, bioactive molecules. © 2016 Elsevier B.V.
Kelsey J.W.,Muhlenberg College |
White J.C.,U.S. Department of Soil and Water
Environmental Toxicology and Chemistry | Year: 2013
The use of engineered nanomaterials has increased dramatically in recent years, but an understanding of nanomaterial fate and effects in the environment is lacking. In particular, the interaction of nanomaterials with coexisting organic contaminants and the subsequent implications for sensitive biota is almost completely unknown. Here, the effect of C60 fullerenes on the accumulation of weathered dichlorodiphenyldichloroethylene (p,p′-DDE; DDT metabolite) by Cucurbita pepo (pumpkin) and Eisenia fetida (earthworm) was determined under single and multispecies conditions. The plants, in the presence or absence of earthworms, were grown in soil containing weathered DDE (200ng/g) and 0 or 1,670mg/kgC60 fullerenes. Plants and earthworms were added either simultaneously or sequentially (earthworms after plants). Neither DDE nor C60 had an impact on survival or biomass of plants and earthworms, although fullerenes significantly decreased (29.6-39.0%) the relative root mass. Under single or multispecies conditions, C60 had little impact on DDE bioaccumulation by either species. The DDE concentrations in non-fullerene-exposed shoots, roots, and earthworms were 181, 7,400, and 8,230ng/g, respectively. On fullerene exposure, the DDE content was nonsignificantly lower at 163, 7280, and 7540ng/g, respectively. In the presence of the earthworms, C60 significantly decreased the shoot DDE content (28.6%), but no impact on root concentrations was observed. Root DDE content was unaffected by the presence of fullerenes and decreased by 21.6 to 37.5% during coexposure with earthworms. Earthworm DDE content was decreased by plant presence. Earthworms added to soils after plant harvest accumulated more DDE but were unaffected by the C60 exposure. Additional work is necessary, but these findings suggest that fullerenes may have minimal impact on the bioaccumulation of weathered cocontaminants in soil. © 2013 SETAC.
Esacove A.W.,Muhlenberg College
Sociology of Health and Illness | Year: 2013
The expanding reliance on the health sciences to address social problems is well documented, as are the effects of the social construction of public (health) problems on 'target' populations, intervention design and broader social systems. Less attention has been given in the literature to the cultural meanings that configure public health efforts themselves. This study demonstrates how the cultural understandings of sex and sexuality that inform US human immunodeficiency virus (HIV) prevention policy in sub-Saharan Africa shape policy recommendations. Based on an analysis of 119 US policy documents, a relatively stable and highly gendered narrative of sexual risk was found across the Clinton and (G.W.) Bush administrations. This narrative locates HIV risk in (what is constructed to be) the inevitable clash between women's sexuality and men's sexuality, and delineates HIV risk by the form of relationship in which sex occurs. The two narratives diverge at this point, offering different definitions of 'bad' sex and 'good' sex. This divergence helps to explain the different prevention foci of the administrations - condoms during the Clinton era and abstinence-outside-of-marriage during the Bush administration. In both cases, the sexual risk narrative points to individual targeted prevention strategies, even as the policy identifies structural factors as driving global HIV epidemics. © 2012 The Author. Sociology of Health & Illness © 2012 Foundation for the Sociology of Health & Illness/Blackwell Publishing Ltd.
Kussmaul C.,Muhlenberg College
SIGCSE'12 - Proceedings of the 43rd ACM Technical Symposium on Computer Science Education | Year: 2012
This paper describes an ongoing project to develop activities for computer science (CS) using process oriented guided inquiry learning (POGIL). First, it reviews relevant background on effective learning and POGIL, compares POGIL to other forms of active learning, and describes the potential of POGIL for CS. Second, it describes a sample POGIL activity, including the structure and contents, student and facilitator actions during the activity, and how activities are designed. Third, it summarizes current progress and plans for a NSF TUES project to development POGIL materials for CS. Finally, it discusses student feedback and future directions. © 2012 ACM.