Colleagues, Classmates, and Friends: Graduate versus Undergraduate Tutor Identities and Professionalization

This study provides a new framework for thinking about the value of writing center work by illuminating how tutors define and negotiate their various and emergent identities as students and as professionals. We build on conversations about tutor identity to argue that tutors’ multiple roles affect the dynamics of the writing center as a whole. From interviews with graduate and undergraduate tutors about professionalization and the writing center, we reveal that the tutors’ level of resistance to or acceptance of writing center work impacts the extent to which they see themselves as burgeoning professionals within that space and, concomitantly, affects the sense of community in the writing center. At our site of study, undergraduate tutors who self-selected into writing center employment generally had much more positive associations with their writing center experiences than their graduate student counterparts, who were often compelled to work in the center as part of their assistantships. We argue then that while writing centers can be valuable in building the professional identities of both undergraduate and graduate tutors, the ways in which these different populations affect our centers is significant. As such, writing center professionals at all levels should work to acknowledge different identities and foster community among tutors who come to us with multiple backgrounds, purposes, and agendas.University Writing Cente

Microwave diode amplifiers with low intermodulation distortion

Distortions can be greatly reduced in narrow-band applications by using the second harmonic. The ac behavior of simplified diode amplifier has negative resistance depending on slope of equivalent I-V curve

Enhancing stem cell engraftment and function following corneal stem cell transplantation

Transplantation of limbal epithelial stem cells (LESCs) can be an effective treatment for patients with Limbal Stem Cell Deficiency (LSCD), a condition where loss or damage of corneal stem cells results in painful inflammation and blindness. However, failure rates of both auto- and allografted cultured LESCs are high despite systemic immune suppression, for which the reasons are unclear. This project aimed to investigate variables important for successful engraftment, including graft stem cell composition, the graft bed inflammatory microenvironment, and the role of the immune system in corneal epithelial graft rejection. We developed a mouse model of LSCD induced by chemical injury, able to accurately recapitulate features of the LSCD phenotype seen in human patients including corneal haze, epithelial defects, and neovascularisation accompanied by significant cellular infiltration into the cornea. We also demonstrated successful regeneration of the LSCD injury by transplanting sheets of corneal epithelium containing LESCs, while tracking engraftment and growth kinetics during wound healing. Transplant of allogeneic donor derived epithelial grafts demonstrated characteristic signs of graft rejection including significant cellular infiltration into the cornea and expression of inflammatory cytokines and chemokines. Adoptive transfer of fluorescently labelled purified allogeneic immune cell subsets, including CD4+ and CD8+ T cells, to immunodeficient transplant recipients demonstrated their effect on stable epithelial grafts in vivo. This project also aimed to develop strategies for the isolation and enrichment of LESC from primary human corneas. Several methods of tissue digestion and LESC isolation were compared, and the inflammatory chemokine and cytokine profile of primary human corneal epithelial and stromal cells was investigated in vitro

Determination of the number of atoms trapped in an optical cavity

The number of atoms trapped within the mode of an optical cavity is determined in real time by monitoring the transmission of a weak probe beam. Continuous observation of atom number is accomplished in the strong coupling regime of cavity quantum electrodynamics and functions in concert with a cooling scheme for radial atomic motion. The probe transmission exhibits sudden steps from one plateau to the next in response to the time evolution of the intracavity atom number, from Ngreater than or equal to 3 to N=2-->1-->0 atoms, with some trapping events lasting over 1 s