Extraneous Voices: Orphaned and Adopted Texts in the Protagoras

The Protagoras features the first known venture into detailed textual interpretation in the Western intellectual tradition. Yet if Socrates is to be taken at his wordat the close of his hermeneutic contest with Protagoras, this venture is to be regarded as a playful demonstration of the worthlessness of texts for aiding in the pursuit of knowledge. This essay is an attempt to view Socrates’ puzzling remarks on this point within their dramatic and historical contexts. I argue that, far from having us lay our inherited texts aside, we can find in the Protagoras a reorientation to the linked activities of reading and dialogue, where we need not be forced to choose between merely using our own unaided voices and relying upon the voices of others in the project of philosophic education

Analysis of best corrected visual acuity following corneal refractive surgery comparing low and standard predicted postoperative keratometry

BACKGROUND: It is a commonly held view in the ophthalmologic community that eyes with sufficiently low calculated postoperative corneal keratometry, less than 35 diopters, should not undergo corrective refractive laser surgery (CRLS) due to the increased risk of best corrected visual acuity (BCVA) loss. Typical CRLS include Laser In-Situ Keratomileusis (LASIK), Photorefractive Keratectomy (PRK), and Laser-Assisted Sub-Epithelial Keratectomy (LASEK). Evidence for this claim in currently available literature is sparse and inconsistent. PURPOSE: To further elucidate the relationship between calculated “flat” postoperative corneal keratometry and loss of BCVA. Additionally, to investigate the role of procedure type (LASIK, ASA, or LASEK) and degree of calculated postoperative corneal flatness on visual outcomes following CRLS. METHODS: 222 eyes (111 candidates and 111 controls) were retrospectively analyzed and matched based on calculated postoperative keratometry compared to control subgroups with calculated postoperative keratometries ≥38 D and further stratified into subgroups 1b (K=38-38.99 D), 2b (K=39-39.99 D), 3b (K=40-40.9 9D), and 4b (K≥41 D). All of the eyes had undergone LASIK, PRK, or LASEK between December 2008 and November 2016 at Boston Eye Group/Boston Laser in Brookline, MA. RESULTS: Statistical analyses showed no significant differences between candidates and controls in preoperative BCVA (p=0.650) and postoperative BCVA (p=0.081). Subgroup matching showed no significant differences in the amount of tissue ablated in 1a & 1b (p=0.946), 2a & 2b (p=0.694), 3a & 3b (p=0.989), and 4a & 4b (p=0.986). There was also no significant change between preoperative and postoperative BCVA in subgroups 1a (p=0.367), 2a (p=0.297), 3a (p=0.576), 4a (p=0.669), 1b (p=0.458), 2b (p=0.227), 3b (p=0.071), or 4b (p=0.703). 3 of 111 (2.70%) candidate eyes and 1 (0.90%) control eye lost 1+ lines of BCVA following surgery. There was no statistical difference in 1+ lines of BCVA lost between these groups (p=0.313). Similarly, the type of CRLS undergone did not affect the rate of BCVA line loss (p=0.793). CONCLUSION: Our evidence suggests that in a matched comparison of flat and normal mathematically predicted postoperative keratometries, there was no increase in BCVA lost due to flat keratometry

Generating functions for plateaus in Motzkin paths

A plateau in a Motzkin path is a sequence of three steps: an up step, a horizontal step, then a down step. We find three different forms for the bivariate generating function for plateaus in Motzkin paths, then generalize to longer plateaus. We conclude by describing a further generalization: a continued fraction form from which one can easily derive new multivariate generating functions for various kinds of path statistics. Several examples of generating functions are given using this technique

Site occupancy analysis of the sagebrush lizard (Sceloporus graciosus) in the disappearing desert-scrub of the Columbia Basin

The shrub-steppe landscape of the Columbia Basin has been the target of agricultural and urban development, and the resulting fragmentation and degradation has led to the disappearance of unique arid mesohabitats. In central Washington, the sandy lowland habitats resembling desert-scrub, which under natural conditions are characterized by a shrub-and-sand mosaic, have become increasingly degraded by humans directly (e.g., flooding, agriculture) or indirectly (e.g. cheatgrass introduction). These habitats have unique community assemblages with species adapted to the sandy substrates and unobstructed matrix between shrubs. While much conservation literature focuses on the loss of shrubsteppe habitat, there has been little research on the effects of loss, fragmentation, and degradation of sandy desert-scrub in the Columbia Basin on small reptile inhabitants. The sagebrush lizard (Sceloporus graciosus), an obligate resident of these sandy habitats, serves as a potential model organism to document the effects of desert-scrub loss and degradation. Compared to historical sightings prior to 1980, scant observations of S. graciosus within the last decade may be a sign that this species might be disappearing from its Washington range. In this study, I aim to assess whether the sagebrush lizard is still present in much of its original range in Washington, and to determine which aspects of their habitat correlates with population density. Sandy desert-scrub habitats that are historically known to have or were capable of having sagebrush lizards in Washington and Oregon were chosen as field sites during the summer and early autumn of 2016. Landcover statistics, such as shrub cover and grass cover, and habitat characteristics including wildfire history were determined for use as potential correlates for the rate of sagebrush lizards encountered in each site. Landcover was quantified via supervised classification using aerial photographs, and model accuracy was verified by comparing transect samples from the field. Multidimensional scaling and analyses of similarity were performed to determine which sites formed groups that were dissimilar to others, and similarity percentages were used to quantify the degree to which each habitat factor contributed to site dissimilarity. In only 6 out of the 16 sites were sagebrush lizards detected during standard search surveys. In Washington, of the 7 surveyed sites with sagebrush lizard sightings within the past 30 years, only 2 (29%) had detectable individuals. There were no differences between sites where sagebrush lizards were present and absent unless sites within 100 m of a crop field were classified separately, whereupon all five of these sites then fell within one out of two groups with 60% similarity. Percent grass cover was the strongest factor contributing to group differences, with less grass and more open sand found in sagebrush lizard-present sites. Also, sagebrush lizard-absent sites had histories of wildfire. The need to separately classify otherwise suitable habitat near agriculture (and did not have sagebrush lizards) indicates additional negative influences affecting this species presence, since not incorporating this sole variable masks any differences among sites. In general, I infer that wildfire, cheatgrass invasion, and landscape development all have reduced suitable habitat for sagebrush lizards and likely explains their absence in their historic range. Given that the remaining pristine sandy desert-scrub habitats are now fragmented and few in number in the state of Washington, I infer from my results that there is very real cause for concern for the viability of this species in the state. If the challenge this species is facing is representative of other arid endemics, then the widespread changes to the shrub-steppe and desert-scrub landscapes in the Western USA provide many research opportunities in conservation ecology

Dendritic cell nediated inhibition of lentiviral infection

Lentiviral entry to quiescent lymphocytes represents a 'time bomb' waiting for cellular activation to spread infection. In order to undergo immune activation T cells interact with dendritic cells presenting peptide:MHC complexes 'sampling' them to look for agonist peptides and receiving survival signals from self peptides. This makes the dendritic cell:T cell interaction an ideal checkpoint to contain lentiviral infection of quiescent lypmhocytes

Analog processing of signals from a CZT strip detector with orthogonal coplanar anodes

We present the requirements, design, and performance of an analog circuit for processing the non-collecting anode strip signals from a cadmium zinc telluride (CZT) strip detector with orthogonal coplanar anodes. Detector signal simulations and measurements with a prototype are used to define the range of signal characteristics as a function of location of the gamma interaction in the detector. The signals from the non- collecting anode strip electrodes are used to define two of the three spatial coordinates including the depth of interaction, the z dimension. Analog signal processing options are discussed. A circuit to process the signals from the non- collecting anode strips and extract from them the depth of interaction is described. The circuit employs a time-over- threshold (TOT) measurement. The performance of the detector prototype with a preliminary version of this circuit is presented, and future development work is outlined

Interleukins 7 and 15 Maintain Human T Cell Proliferative Capacity through STAT5 Signaling

T lymphocytes require signals from self-peptides and cytokines, most notably interleukins 7 and 15 (IL-7, IL-15), for survival. While mouse T cells die rapidly if IL-7 or IL-15 is withdrawn, human T cells can survive prolonged withdrawal of IL-7 and IL-15. Here we show that IL-7 and IL-15 are required to maintain human T cell proliferative capacity through the STAT5 signaling pathway. T cells from humanized mice proliferate better if stimulated in the presence of human IL-7 or IL-15 or if T cells are exposed to human IL-7 or IL-15 in mice. Freshly isolated T cells from human peripheral blood lose proliferative capacity if cultured for 24 hours in the absence of IL-7 or IL-15. We further show that phosphorylation of STAT5 correlates with proliferation and inhibition of STAT5 reduces proliferation. These results reveal a novel role of IL-7 and IL-15 in maintaining human T cell function, provide an explanation for T cell dysfunction in humanized mice, and have significant implications for in vitro studies with human T cells