322 research outputs found
Construction Law: 1991/1992 Survey of Florida Law
There were several appellate decisions concerning construction law from mid - 1991 through mid 1992
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Multiple long-term, experimentally-evolved populations of Escherichia coli acquire dependence upon citrate as an iron chelator for optimal growth on glucose
Background: Specialization for ecological niches is a balance of evolutionary adaptation and its accompanying tradeoffs. Here we focus on the Lenski Long-Term Evolution Experiment, which has maintained cultures of Escherichia coli in the same defined seasonal environment for 50,000 generations. Over this time, much adaptation and specialization to the environment has occurred. The presence of citrate in the growth media selected one lineage to gain the novel ability to utilize citrate as a carbon source after 31,000 generations. Here we test whether other strains have specialized to rely on citrate after 50,000 generations. Results: We show that in addition to the citrate-catabolizing strain, three other lineages evolving in parallel have acquired a dependence on citrate for optimal growth on glucose. None of these strains were stimulated indirectly by the sodium present in disodium citrate, nor exhibited even partial utilization of citrate as a carbon source. Instead, all three of these citrate-stimulated populations appear to rely on it as a chelator of iron. Conclusions: The strains we examine here have evolved specialization to their environment through apparent loss of function. Our results are most consistent with the accumulation of mutations in iron transport genes that were obviated by abundant citrate. The results present another example where a subtle decision in the design of an evolution experiment led to unexpected evolutionary outcomes.Organismic and Evolutionary Biolog
The Case for Rage in Transitional Justice: Lessons from the Anti-Racist Struggle
Transitional justice theorizing has the tendency to smuggle in an over-reliance on dualities: one’s resentment can give rise to either vengeance or forgiveness, but not both; one can either be fueled by anger or by the hope of progress, but not both; and so on. This dualistic way of thinking replicates the kinds of false dichotomies that hamstring other societal movements, among them the struggle against racism. Drawing on Myisha Cherry’s case for so-called ‘Lordean rage’ within the context of the anti-racist movement, I make the case that transitional justice in general would be well-served by centering the transformative power of emotion (even and especially when that emotion defies oversimplified and strict categorization)
The Ability of Flux Balance Analysis to Predict Evolution of Central Metabolism Scales with the Initial Distance to the Optimum
The most powerful genome-scale framework to model metabolism, flux balance analysis (FBA), is an evolutionary optimality model. It hypothesizes selection upon a proposed optimality criterion in order to predict the set of internal fluxes that would maximize fitness. Here we present a direct test of the optimality assumption underlying FBA by comparing the central metabolic fluxes predicted by multiple criteria to changes measurable by a 13C-labeling method for experimentally-evolved strains. We considered datasets for three Escherichia coli evolution experiments that varied in their length, consistency of environment, and initial optimality. For ten populations that were evolved for 50,000 generations in glucose minimal medium, we observed modest changes in relative fluxes that led to small, but significant decreases in optimality and increased the distance to the predicted optimal flux distribution. In contrast, seven populations evolved on the poor substrate lactate for 900 generations collectively became more optimal and had flux distributions that moved toward predictions. For three pairs of central metabolic knockouts evolved on glucose for 600–800 generations, there was a balance between cases where optimality and flux patterns moved toward or away from FBA predictions. Despite this variation in predictability of changes in central metabolism, two generalities emerged. First, improved growth largely derived from evolved increases in the rate of substrate use. Second, FBA predictions bore out well for the two experiments initiated with ancestors with relatively sub-optimal yield, whereas those begun already quite optimal tended to move somewhat away from predictions. These findings suggest that the tradeoff between rate and yield is surprisingly modest. The observed positive correlation between rate and yield when adaptation initiated further from the optimum resulted in the ability of FBA to use stoichiometric constraints to predict the evolution of metabolism despite selection for rate
Personality and functional vision in older adults with age-related macular degeneration
Introduction: The purpose of the study was to determine whether personality traits influence self-reported functional vision in patients with age-related macular degeneration (AMD). Methods: This is a prospective cross-sectional analysis of baseline data from the Low Vision Depression Prevention Trial. Participants (N = 182) over age 65 with bilateral AMD, visual acuity worse than 20/70 in the better-seeing eye, and subthreshold depression were recruited from the Wills Eye Hospital retina practice. Assessments included visual acuity, contrast sensitivity, National Eye Institute Visual Function Questionnaire-25 plus Supplement (NEI VFQ-25) near and distance subscales, depression, and personality testing. Structural equation models were used to investigate the relationship of the NEI VFQ near activities and distance activities with the various demographic, clinical, and psychological predictors. Results: In the single-predictor model for near functional vision, visual acuity at logMAR ≤ 1 (estimate = -0.33 [95% confidence interval {CI} -0.46, -0.20]; p ≤ 0.001), neuroticism (estimate = -0.05 [95% CI -0.08, -0.01]; p = 0.01), and education (estimate = -0.08 [95% CI 0.01, 0.15]; p = 0.03) were statistically significant predictors. In the single-predictor model for distance functional vision, only visual acuity at logMAR ≤ 1 (estimate = -0.49 [95% CI -0.69, -0.29]; p ≤ 0.001) and neuroticism (estimate = -0.09 [95% CI -0.15, 0.02]; p = 0.008) were statistically significant predictors. Discussion: Self-reported functional vision depends on the severity of vision loss as well as the personality trait of neuroticism. Implications for practitioners: Assessment of personality traits, particularly neuroticism, may increase the precision of rating scales of functional vision and suggest new rehabilitative interventions to improve the functional vision and quality of life of patients with AMD © 2014 AFB, All Rights Reserved
GM1 ganglioside in Parkinson\u27s disease: Pilot study of effects on dopamine transporter binding.
OBJECTIVE: GM1 ganglioside has been suggested as a treatment for Parkinson\u27s disease (PD), potentially having symptomatic and disease modifying effects. The current pilot imaging study was performed to examine effects of GM1 on dopamine transporter binding, as a surrogate measure of disease progression, studied longitudinally.
METHODS: Positron emission tomography (PET) imaging data were obtained from a subset of subjects enrolled in a delayed start clinical trial of GM1 in PD [1]: 15 Early-start (ES) subjects, 14 Delayed-start (DS) subjects, and 11 Comparison (standard-of-care) subjects. Treatment subjects were studied over a 2.5 year period while Comparison subjects were studied over 2 years. Dynamic PET scans were performed over 90 min following injection of [(11)C]methylphenidate. Regional values of binding potential (BPND) were analyzed for several striatal volumes of interest.
RESULTS: Clinical results for this subset of subjects were similar to those previously reported for the larger study group. ES subjects showed early symptomatic improvement and slow symptom progression over the study period. DS and Comparison subjects were initially on the same symptom progression trajectory but diverged once DS subjects received GM1 treatment. Imaging results showed significant slowing of BPND loss in several striatal regions in GM1-treated subjects and in some cases, an increased BPND in some striatal regions was detected after GM1 use.
INTERPRETATION: Results of this pilot imaging study provide additional data to suggest a potential disease modifying effect of GM1 on PD. These results need to be confirmed in a larger number of subjects
Surgical Apgar Score (SAS) Predicts Perioperative Morbidity and Length of Stay in Patients Undergoing Esophagectomy at a High-Volume Center
Background:
Esophagectomy is a procedure that carries considerable morbidity. Many studies have evaluated factors to predict patients at risk and improve clinical outcomes. The aim of this study was to determine whether the SAS predicts complications, length of stay, and anastomotic leak for patients undergoing esophagectomy at a high-volume institution.https://jdc.jefferson.edu/surgeryposters/1002/thumbnail.jp
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