Site-saturation studies of β-lactamase: Production and characterization of mutant β-lactamases with all possible amino acid substitutions at residue 71

A mutagenic technique that "saturates" a particular site in a protein with all possible amino acid substitutions was used to study the role of residue 71 in β-lactamase (EC 3.5.2.6). Threonine is conserved at residue 71 in all class A β-lactamases and is adjacent to the active site Ser-70. All 19 mutants of the enzyme were characterized by the penam and cephem antibiotic resistance they provided to Escherichia coli LS1 cells. Surprisingly, cells producing any of 14 of the mutant β-lactamases displayed appreciable resistance to ampicillin; only cells with mutants having Tyr, Trp, Asp, Lys, or Arg at residue 71 had no observable resistance to ampicillin. However, the mutants are less stable to cellular proteases than wild-type enzyme is. These results suggest that Thr-71 is not essential for binding or catalysis but is important for stability of the β-lactamase protein. An apparent change in specificity indicates that residue 71 influences the region of the protein that accommodates the side chain attached to the β-lactam ring of the substrate

Federal Grant Applications: What You Need to Know Before You Start Writing

Sometimes disaster relief arrives as a US Department of Agriculture (USDA) grant, and there may be more grants resulting from the COVID-19 pandemic. While obtaining a grant is appealing, many producers overlook grant application details causing many grant proposals to be rejected immediately, before they are read or considered. The checklist provided by this brief will help producers prepare grant applications and avoid common pitfalls

Liquid rocket engine flight certification

The following subject areas are covered: current rocket engine certification process; certification issues; engine characteristics; engine design and mission requirements; structural design criteria; structural design factors of safety; component/subsystem testing; system level development tests; certification/qualification tests; observations; and proposed actions/programs

Market-Based Instruments for the Optimal Control of Invasive Insect Species: B. Tabaci in Arizona

Invasive insect species represent perhaps one of the most significant potential sources of economic risk to U.S. agricultural production. Private control of invasive insect species is likely to be insufficient due to negative externality and weaker-link public good problems. In this study, we compare a system of Pigouvian taxes with tradable permits for invasive species control. While the emissions control literature shows that taxes are preferred to permits under cost uncertainty, invasive-species control involves correlated cost and benefit uncertainty. Hence, we expect a quantity-based system to be preferred. Monte Carlo simulations of optimal steady-state outcomes confirm our expectations.externalities, invasive species, optimal control, permits, spatial-temporal model, taxes, Crop Production/Industries, Resource /Energy Economics and Policy,

Market-Based Instruments for the Optimal Control of Invasive Insect Species: B. Tabaci in Arizona

Invasive insect species represent perhaps one of the most significant potential sources of economic risk to U.S. agricultural production. Private control of invasive insect species is likely to be insufficient due to negative externality and weaker-link public good problems. In this study, we compare a system of Pigouvian taxes with tradable permits for invasive species control. While the emissions control literature shows that taxes are preferred to permits under cost uncertainty, invasive species control involves correlated cost and benefit uncertainty, so we expect a quantity-based system to be preferred. Monte Carlo simulations of optimal steady-state outcomes confirm our expectations.externalities, invasive species, optimal control, permits, spatial-temporal model, taxes., Environmental Economics and Policy, Public Economics, Risk and Uncertainty, H23, L51, Q28, Q57.,

Exploring Critical Events in an Inaugural Arts-Based Research Class through Ethnographic Mapping and Poetry-Enriched Narrative Sketches

Arts-based research (ABR) employs the arts to explore the “experiences of researchers and the people they involve in their studies” (McNiff, 2008, p. 29). Acknowledgement of ABRs’ potential for enhancing social science inquiry has gained momentum along with the development of new ABR methods courses. However, there is a lack of published studies that investigate what goes on in ABR classes (Cahnmann-Taylor & Siegesmund, 2008; Leavy, 2015; Personal communication, The Qualitative Report 2018 Conference). In this inquiry we (Janet, course designer and instructor, and Steve, student and class assistant), employed ethnographic techniques to explore unexpected critical events that occurred in our inaugural ABR class. We wanted to discover why these problematic situations happened. We also hoped to learn how we might have anticipated and resolved these events before they became challenging. Similar to a bricolage process in which researchers cobble different modes of inquiry together, we interfaced ethnographic mapping with poetry-enriched narrative sketches to record and make sense of the data. We discovered some critical events resulted from circumstances outside of the classroom and other incidents were exacerbated because we did not attend to problems when they first developed

Exploring Perceptions of Key Events in a Qualitative Research Class: Applying Some Principles of Collaborative Analytic Inquiry in Practice

Little research portrays collaborative analytic inquiry in practice. Drawing on our dual lenses, we, a professor and a doctoral student in an advanced qualitative methods course, applied principles of collaborative analytic inquiry to construct new understandings about key events that occurred during an advanced qualitative research class. Using asynchronous e-mail communication, we shared, affirmed, and questioned each other’s and our own storied recollections of moments of joy and learning intertwined with some challenging issues. To begin our inquiry, we planned and negotiated our responsibilities, voiced our concerns and questions pertinent to the project, and avowed our willingness to risk emotional vulnerability and discomfort as we confronted our truths. We also studied the extant literature to learn about analytic inquiry since our work, followed some tenets of this research method. We conducted our work in three phases. In the third phase of our study we documented what we believed were significant, problematic issues in the course and responded to each other’s and our own assumptions. Our reflections helped us establish the value of collaborative analytic inquiry to create space for self-study. In the process of our work we came to recognize that the broad themes in our research, although not generalizable, might occur in any teaching context