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Observations of a regular pulse burst (RPB) at the end of a K‐event are analyzed utilizing a simple geometric model and particle swarm optimization (PSO) to estimate the currents and propagation speeds of successive pulses of the RPB. The results show that the current of successive pulses is strongly overlapped and, for typical speeds of continuously propagating K‐events, are unphysically large (88 kA), exceeding the currents of most strokes to ground. By default, the unphysical nature of the result, coupled with very high frequency interferometer observations of an RPB in Florida, shows that the propagation speed of the pulses is significantly faster than expected, namely ∼0.6–1.8 × 108 m/s. This reduces the inferred current from 88 kA down to 6–18 kA, typical of intracloud events. The fast propagation speed of the stepping is explained by successive pulses retracing much of the path of the preceding pulses due to the successive pulses being strongly overlapped. Plain Language Summary: Regular pulse bursts (RBP) are a spectacular phenomenon in lightning studies, in which rapidly propagating, conductive channels called K‐events transition from a smoothly and continually lengthening channel to an intermittent but regularly‐spaced stepping process, with each step producing a highly‐impulsive current and electric field change, or "sferic." Here we introduce a new approach for analyzing sferic observations that models the K‐event as a series of successive segments, with the parameters of the current and extent of each pulse being determined by searching the multi‐dimensional parameter space that best fits the corresponding pulse waveforms. This was done using a process called PSO, and indicated that the RBP pulses were caused by a succession of overlapping fast breakdown events, but having unphysically strong currents. For the distant measurements of the study, the sferic amplitudes can determine only the product of current and propagation speed of the pulses, causing their current and speed values to be ambiguous. However, for the currents to have reasonable values, we are able to conclude that the speeds needed to be faster than assumed maximum value of 1.5 × 107 m/s value in the analysis. This contention is supported by observations of similar RPBs being studied by the authors. Key Points: A new, innovative method is developed for estimating the currents and extents of fast electric field change pulsesThe method is applied to the study of a regular pulse burst, showing that it consisted of a succession of fast overlapping eventsThe speed of the pulses is inferred to be significantly higher than that of continuously‐developing K‐leader [ABSTRACT FROM AUTHOR]

Purpose: To determine what socioeconomic factors affect follow-up in a glaucoma screening program. Patients and Methods: This was a retrospective cohort study of six health fairs in South Florida from October 2012 to March 2013 among socially and economically disadvantaged populations. Visual acuity (VA), intraocular pressure (IOP), cup-to-disc ratio (CDR), and visual field testing were obtained to identify glaucoma suspects. Glaucoma suspects were defined as having intraocular pressure ≥ 24 mm Hg, cup-to-disc ratio of ≥ 0.6 in either eye, or glaucomatous defects on visual field testing. In July 2015, telephone surveys were administered to assess follow up and socioeconomic factors. Results: Seventy-two out of 144 (50%) glaucoma suspects responded to the survey and were included in the analysis. Of the 72 respondents, average age was 52.8 years old and 65% were female. The most common race was African American (69%) and ethnicity was Haitian (51%). Glaucoma suspects who followed up were significantly more likely to have health insurance compared to those who did not follow up (74% vs 43%, p = 0.014). No significant difference in follow-up based on age (p = 0.125), education (p = 0.151), gender (p = 0.48), or ethnicity (p = 0.707) was identified. Of the 30 respondents, who did not follow up, the most common reasons were "no insurance" (57%, 17/30) and "not worried" (33%, 10/30). Conclusion: Insurance was the main socioeconomic factor in determining whether glaucoma suspects followed up after community health screenings. Streamlining social services could increase clinical access of glaucoma suspects. [ABSTRACT FROM AUTHOR]

Purpose: We examined individual-level and neighborhood-level predictors of mortality in CRC patients diagnosed in Florida to identify high-risk groups for targeted interventions. Methods: Demographic and clinical data from the Florida Cancer Data System registry (2007–2011) were linked with Agency for Health Care Administration and US Census data (n = 47,872). Cox hazard regression models were fitted with candidate predictors of CRC survival and stratified by age group (18–49, 50–64, 65+). Results: Stratified by age group, higher mortality risk per comorbidity was found among youngest (21%), followed by middle (19%), and then oldest (14%) age groups. The two younger age groups had higher mortality risk with proximal compared to those with distal cancer. Compared with private insurance, those in the middle age group were at higher death risk if not insured (HR = 1.35), or received healthcare through Medicare (HR = 1.44), Medicaid (HR = 1.53), or the Veteran’s Administration (HR = 1.26). Only Medicaid in the youngest (52% higher risk) and those not insured in the oldest group (24% lower risk) were significantly different from their privately insured counterparts. Among 18–49 and 50–64 age groups there was a higher mortality risk among the lowest SES (1.17- and 1.23-fold higher in the middle age and 1.12- and 1.17-fold higher in the older age group, respectively) compared to highest SES. Married patients were significantly better off than divorced/separated (HR = 1.22), single (HR = 1.29), or widowed (HR = 1.19) patients. Conclusion: Factors associated with increased risk for mortality among individuals with CRC included being older, uninsured, unmarried, more comorbidities, living in lower SES neighborhoods, and diagnosed at later disease stage. Higher risk among younger patients was attributed to proximal cancer site, Medicaid, and distant disease; however, lower SES and being unmarried were not risk factors in this age group. Targeted interventions to improve survivorship and greater social support while considering age classification may assist these high-risk groups. [ABSTRACT FROM AUTHOR]

Background: The Loewenstein-Acevedo Scales for Semantic Interference and Learning (LASSI-L) is an increasingly utilized cognitive stress test designed to identify early cognitive changes associated with incipient neurodegenerative disease., Objective: To examine previously derived cut-points for cognitively unimpaired older adults that were suggestive of performance impairment on multiple subscales of the LASSI-L. These cut-points were applied to a new sample of older adults who were cognitive healthy controls (HC: n = 26) and those on the Alzheimer's disease (AD) continuum from early stage mild cognitive impairment (EMCI: n = 28), late stage MCI (LMCI: n = 18) to mild AD (AD: n = 27)., Methods: All participants were administered the LASSI-L. All cognitively impaired participants were PET amyloid positive which likely reflects underlying AD neuropathology, while cognitively normal counterparts were deemed to have amyloid negative scans., Results: There was a monotonic relationship between the number of deficits on LASSI-L subscales and independent classification of study groups with greater severity of cognitive impairment. Importantly, taken together, impairment on maximum learning ability and measures of proactive semantic interference (both reflected by cued recall and intrusion errors) correctly classified 74.1% of EMCI, 94.4% of LMCI, and 96.3% of AD. Only 7.7% of HC were incorrectly classified as having impairments., Conclusion: A modest number of LASSI-L subscales taking approximately 8 minutes to administer, had excellent discriminative ability using established cut-offs among individuals with presumptive stages of AD. This has potential implications for both clinical practice and clinical research settings targeting AD during early prodromal stages.

Objectives: We explored the mediational relationships among smoking, dental visits, and oral health in a longitudinal study., Methods: We selected a sample of adult residents of rural communities of North Central Florida and followed them for 3 years (final N = 1170). We examined the impact of smoking on oral health across time and conducted mediation analysis to quantify the effect of dental visits on the relationship between smoking and poor oral health., Results: Our results showed that oral health declined across time for smokers but not for nonsmokers. The mediation analysis found that 18.3% of the difference in followup oral health between smokers and non-smokers was explained by smokers not having any dental visits in the last year., Conclusions: Our findings suggest that, given the low success rate of quitting smoking, promoting dental visits can help limit the negative effects of smoking on oral health. Future community prevention studies could encourage dental visits among smokers and provide educational materials that aim to increase knowledge of oral self-care.