Folklore for a New Generation: Charles Chesnutt\u27s Updated Trickster Figure

Amidst a surge of plantation fiction writing during the era of American Realism, Charles Chesnutt was arguably one of the most controversial yet prolific authors to address the recent advent of slavery. The Conjure Woman was a publication of seven frame narratives that employed the traditional style of a former slave telling tales of “the old days,” and though Chesnutt\u27s work may have mirrored such authors as Thomas Nelson Page, the tales broke from tradition with surprisingly stark accounts that are clearly based on Chesnutt\u27s own conversations with former slaves. Much like another contemporary, Joel Chandler Harris, Chesnutt looks backward to the trickster figure of African lore and applies its tactics to his narrator, Julius McAdoo, to deliver a comical yet austere discussion of the ills of slavery. In The Conjure Woman, Chesnutt addresses the issues of forced separation of families, slave abuse, dark superstition and the ever-present peril of competition among slaves for limited resources. Furthermore, Chesnutt\u27s use of the trickster figure from Old World lore works to not only symbolize the clash between old and new ideologies, but serves to offer an in-road to brokering peace between white Americans and the newly emancipated slaves. This discussion addresses Chesnutt\u27s updated trickster figure: its similarities to the Old World trickster, its distinguishing qualities that modernized the figure and the role that it plays in The Conjure Woman

Calibration Modeling Methodology to Optimize Performance for Low Range Applications

Calibration is a vital process in characterizing the performance of an instrument in an application environment and seeks to obtain acceptable accuracy over the entire design range. Often, project requirements specify a maximum total measurement uncertainty, expressed as a percent of full-scale. However in some applications, we seek to obtain enhanced performance at the low range, therefore expressing the accuracy as a percent of reading should be considered as a modeling strategy. For example, it is common to desire to use a force balance in multiple facilities or regimes, often well below its designed full-scale capacity. This paper presents a general statistical methodology for optimizing calibration mathematical models based on a percent of reading accuracy requirement, which has broad application in all types of transducer applications where low range performance is required. A case study illustrates the proposed methodology for the Mars Entry Atmospheric Data System that employs seven strain-gage based pressure transducers mounted on the heatshield of the Mars Science Laboratory mission

Responses of bullfrog tadpoles to hypoxia and predators

Low dissolved oxygen concentrations present numerous challenges for non-air-breathing aquatic organisms. Amphibian larvae and their predators can respond to oxygen levels by altering their behavior and physiology, but the ecological consequences of these responses are generally unknown. We conducted two laboratory experiments to study the effects of dissolved oxygen on respiratory behavior and susceptibility to predation of larval bullfrogs ( Rana catesbeiana ). In the first, we exposed small, lungless tadpoles to a predatory salamander larva ( Ambystoma tigrinum ) under high and low oxygen conditions. More tadpoles were consumed in high oxygen tanks than in low ones, presumably because salamanders remained near the surface in the low oxygen tanks while most tadpoles rested on the bottom. Tadpole activity depended on both oxygen and predator presence: swimming decreased after addition of salamanders under high oxygen, but increased under low oxygen. In the second experiment, we examined the effect of predator chemical cues on the air-breathing rate of large tadpoles with well-developed lungs under low oxygen conditions. In the presence of chemical cues produced by dragonfly larvae consuming bullfrog tadpoles, air-breathing and swimming were significantly reduced relative to controls. These experiments demonstrate the potential impact of dissolved oxygen on predator-prey interactions, and suggest that outcomes depend on the respiratory ecology of both predator and prey.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42283/1/442-125-2-301_s004420000451.pd

Early outcomes from a randomized, controlled trial of supervised exercise, angioplasty, and combined therapy in intermittent claudication

BACKGROUND: To compare angioplasty (PTA), supervised exercise (SEP) and PTA + SEP in the treatment of intermittent claudication (IC) due to femoropopliteal disease. METHODS: Over a 6-year period, 178 patients (108 men; median age, 70 years) with femoropopliteal lesions suitable for angioplasty were randomized to PTA, SEP, or PTA + SEP. Patients were assessed prior to and at 1 and 3 months post treatment. ISCVS outcome criteria (ankle pressures, treadmill walking distances) and quality of life (QoL) questionnaires (SF-36 and VascuQoL) were analyzed. RESULTS: All groups were well matched at baseline. Twenty-one patients withdrew. Results are as follows: Intragroup analysis: All groups demonstrated significant clinical and QoL improvements (Friedman test, p 0.05). CONCLUSION: SEP should be the primary treatment for the patients with claudication and PTA should be supplemented by an SEP

Peak wall stress measurement in elective and acute abdominal aortic aneurysms

BackgroundAbdominal aortic aneurysm (AAA) rupture occurs when wall stress exceeds wall strength. Engineering principles suggest that aneurysm diameter is only one aspect of its geometry that influences wall stress. Finite element analysis considers the complete geometry and determines wall stresses throughout the structure. This article investigates the interoperator and intraoperator reliability of finite element analysis in the calculation of peak wall stress (PWS) in AAA and examines the variation in PWS in elective and acute AAAs.MethodFull ethics and institutional approval was obtained. The study recruited 70 patients (30 acute, 40 elective) with an infrarenal AAA. Computed tomography (CT) images were obtained of the AAA from the renal vessels to the aortic bifurcation. Manual edge extraction, three-dimensional reconstruction, and blinded finite element analysis were performed to ascertain location and value of PWS. Ten CT data sets were analyzed by four different operators to ascertain interoperator reliability and by one operator twice to ascertain intraoperator reliability. An intraclass correlation coefficient was obtained. The Mann-Whitney U test and independent samples t test compared groups for statistical significance.ResultsThe intraclass correlation coefficient was 0.71 for interoperator reliability and 0.84 for intraoperator reliability. There was no statistically significant difference in the mean (SD) maximal AAA diameter between elective (6.47 [1.30] cm) and acute (7.08 [1.39] cm) patients (P = .073). The difference in PWS between elective (0.67 [0.30] MPa) and acute (1.11 [0.51] MPa) patients (P = .008) was statistically significant, however.ConclusionInteroperator and intraoperator reliability in the derivation of PWS is acceptable. PWS, but not maximal diameter, was significantly higher in acute AAAs than in elective AAAs

Regulation of polarised growth in fungi

Polarised growth in fungi occurs through the delivery of secretory vesicles along tracks formed by cytoskeletal elements to specific sites on the cell surface where they dock with a multiprotein structure called the exocyst before fusing with the plasmamembrane. The budding yeast, Saccharomyces cerevisiae has provided a useful model to investigate the mechanisms involved and their control. Cortical markers, provided by bud site selection pathways during budding, the septin ring during cytokinesis or the stimulation of the pheromone response receptors during mating, act through upstream signalling pathways to localise Cdc24, the GEF for the rho family GTPase, Cdc42. Cdc42 in its GTP-bound activates a multiprotein protein complex called the polarisome which nucleates actin cables along which the secretory vesicles are transported to the cell surface. Hyphae can elongate at a rate orders of magnitude faster than the extension of a yeast bud, so understanding hyphal growth will require substantial modification of the yeast paradigm. The rapid rate of hyphal growth is driven by a structure called the Spitzenkörper, located just behind the growing tip and which is rich in secretory vesicles. It is thought that secretory vesicles are delivered to the apical region where they accumulate in the Spitzenkörper. The Spitzenkörper then acts as vesicle supply centre in which vesicles exit the Spitzenkörper in all directions, but because of its proximity, the tip receives a greater concentration of vesicles per unit area than subapical regions. There are no obvious equivalents to the bud site selection pathway to provide a spatial landmark for polarised growth in hyphae. However, an emerging model is the way that the site of polarised growth in the fission yeast, Schizosaccharomyces pombe, is marked by delivery of the kelch repeat protein, Tea1, along microtubules. The relationship of the Spitzenkörper to the polarisome and the mechanisms that promote its formation are key questions that form the focus of current research