31,533 research outputs found
An Online Decision-Theoretic Pipeline for Responder Dispatch
The problem of dispatching emergency responders to service traffic accidents,
fire, distress calls and crimes plagues urban areas across the globe. While
such problems have been extensively looked at, most approaches are offline.
Such methodologies fail to capture the dynamically changing environments under
which critical emergency response occurs, and therefore, fail to be implemented
in practice. Any holistic approach towards creating a pipeline for effective
emergency response must also look at other challenges that it subsumes -
predicting when and where incidents happen and understanding the changing
environmental dynamics. We describe a system that collectively deals with all
these problems in an online manner, meaning that the models get updated with
streaming data sources. We highlight why such an approach is crucial to the
effectiveness of emergency response, and present an algorithmic framework that
can compute promising actions for a given decision-theoretic model for
responder dispatch. We argue that carefully crafted heuristic measures can
balance the trade-off between computational time and the quality of solutions
achieved and highlight why such an approach is more scalable and tractable than
traditional approaches. We also present an online mechanism for incident
prediction, as well as an approach based on recurrent neural networks for
learning and predicting environmental features that affect responder dispatch.
We compare our methodology with prior state-of-the-art and existing dispatch
strategies in the field, which show that our approach results in a reduction in
response time with a drastic reduction in computational time.Comment: Appeared in ICCPS 201
Increased systemic inflammation is associated with cardiac and vascular dysfunction over the first 12 weeks of antiretroviral therapy among undernourished, HIV-infected adults in Southern Africa.
This is an open-access article distributed
under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the
original author and source are credited.INTRODUCTION: Persistent systemic inflammation is associated with mortality among undernourished, HIV-infected adults starting antiretroviral therapy (ART) in sub-Saharan Africa, but the etiology of these deaths is not well understood. We hypothesized that greater systemic inflammation is accompanied by cardiovascular dysfunction over the first 12 weeks of ART. METHODS: In a prospective cohort of 33 undernourished (body mass index <18.5 kg/m2) Zambian adults starting ART, we measured C-reactive protein (CRP), tumor necrosis factor-α receptor 1 (TNF-α R1), and soluble CD163 and CD14 at baseline and 12 weeks. An EndoPAT device measured the reactive hyperemia index (LnRHI; a measure of endothelial responsiveness), peripheral augmentation index (AI; a measure of arterial stiffness), and heart rate variability (HRV; a general marker of autonomic tone and cardiovascular health) at the same time points. We assessed paired changes in inflammation and cardiovascular parameters, and relationships independent of time point (adjusted for age, sex, and CD4+ T-cell count) using linear mixed models. RESULTS: Serum CRP decreased (median change -3.5 mg/l, p=0.02), as did TNF-α R1 (-0.31 ng/ml, p<0.01), over the first 12 weeks of ART. A reduction in TNF-α R1 over 12 weeks was associated with an increase in LnRHI (p=0.03), and a similar inverse relationship was observed for CRP and LnRHI (p=0.07). AI increased in the cohort as a whole over 12 weeks, and a reduction in sCD163 was associated with a rise in the AI score (p=0.04). In the pooled analysis of baseline and 12 week data, high CRP was associated with lower HRV parameters (RMSSD, p=0.01; triangular index, p<0.01), and higher TNF- α R1 accompanied lower HRV (RMSSD, p=0.07; triangular index, p=0.06). CONCLUSIONS: Persistent inflammation was associated with impaired cardiovascular health over the first 12 weeks of HIV treatment among undernourished adults in Africa, suggesting cardiac events may contribute to high mortality in this population.This work was supported by the Vanderbilt
Meharry Center for AIDS Research (NIH grant number P30 AI54999); the NIH
Fogarty International Center, Office of the Director, National Institutes of Health,
National Heart, Blood, and Lung Institute, and National Institute of Mental Health,
through the Vanderbilt-Emory-Cornell-Duke Consortium for Global Health Fellows
(grant number R25 TW009337); the National Center for Advancing Translational
Sciences (CTSA award number UL1TR000445) and the European and Developing
Countries Clinical Trials Partnership (grant IP.2009.33011.004)
Shed urinary ALCAM is an independent prognostic biomarker of three-year overall survival after cystectomy in patients with bladder cancer.
Proteins involved in tumor cell migration can potentially serve as markers of invasive disease. Activated Leukocyte Cell Adhesion Molecule (ALCAM) promotes adhesion, while shedding of its extracellular domain is associated with migration. We hypothesized that shed ALCAM in biofluids could be predictive of progressive disease. ALCAM expression in tumor (n = 198) and shedding in biofluids (n = 120) were measured in two separate VUMC bladder cancer cystectomy cohorts by immunofluorescence and enzyme-linked immunosorbent assay, respectively. The primary outcome measure was accuracy of predicting 3-year overall survival (OS) with shed ALCAM compared to standard clinical indicators alone, assessed by multivariable Cox regression and concordance-indices. Validation was performed by internal bootstrap, a cohort from a second institution (n = 64), and treatment of missing data with multiple-imputation. While ALCAM mRNA expression was unchanged, histological detection of ALCAM decreased with increasing stage (P = 0.004). Importantly, urine ALCAM was elevated 17.0-fold (P < 0.0001) above non-cancer controls, correlated positively with tumor stage (P = 0.018), was an independent predictor of OS after adjusting for age, tumor stage, lymph-node status, and hematuria (HR, 1.46; 95% CI, 1.03-2.06; P = 0.002), and improved prediction of OS by 3.3% (concordance-index, 78.5% vs. 75.2%). Urine ALCAM remained an independent predictor of OS after accounting for treatment with Bacillus Calmette-Guerin, carcinoma in situ, lymph-node dissection, lymphovascular invasion, urine creatinine, and adjuvant chemotherapy (HR, 1.10; 95% CI, 1.02-1.19; P = 0.011). In conclusion, shed ALCAM may be a novel prognostic biomarker in bladder cancer, although prospective validation studies are warranted. These findings demonstrate that markers reporting on cell motility can act as prognostic indicators
The Mississippian fin de siècle in the middle Cumberland region of Tennessee
Bayesian chronological modeling is used to investigate the chronology for a large-scale human depopulation event during the Mississippian period (AD 1000–1600) known as the Vacant Quarter phenomenon. The Middle Cumberland region (MCR) of Tennessee is within the Vacant Quarter area, and six villages from the final phase of Mississippian activity in the MCR have been subjected to radiocarbon dating. Complete radiocarbon datasets from these sites are presented within an interpretative Bayesian statistical framework. The results provide a unique history of each settlement and demonstrate that Mississippian occupations at each site likely terminated in the mid- to late fifteenth and possibly early sixteenth centuries AD, which is 50 to 100 years later than the most recent estimate for the timing of the Vacant Quarter. Mississippian abandonment in the MCR was relatively quick, likely occurring over less than a century. The exact reasons for abandonment are not entirely clear but appear to be linked to climate change. A radiocarbon simulation experiment indicates that future robust radiocarbon dating with well-selected samples could greatly improve the chronological precision for this late Mississippian activity. More broadly, this example demonstrates that model building with radiocarbon simulations can be used to address regional-scale chronological issues within the American Southeast and beyond
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Optimization of Window Positions for Wind-Driven Natural Ventilation Performance
This paper optimizes opening positions on building facades to maximize the natural ventilation’s potential for ventilation and cooling purposes. The paper demonstrates how to apply computational fluid dynamics (CFD) simulation results to architectural design processes, and how the CFD-driven decisions impact ventilation and cooling: (1) background: A CFD helps predict the natural ventilation’s potential, the integration of CFD results into design decision-making has not been actively practiced; (2) methods: Pressure data on building facades were obtained from CFD simulations and mapped into the 3D modeling environment, which were then used to identify optimal positions of two openings of a zone. The effect of the selected opening positions was validated with building energy simulations; (3) results: The cross-comparison study of different window positions based on different geographical locations quantified the impact on natural ventilation effectiveness; and (4) conclusions: The optimized window positions were shown to be effective, and some optimal solutions contradicted the typical cross-ventilation strategy
Measuring the Effects of a Land Value Tax on Land Development
The objective of this research is to evaluate a land value tax as a potential policy tool to moderate sprawling development in Nashville, TN, the nation’s most sprawling metropolitan community with a population of one million or more. To achieve this objective, the hypothesis is empirically tested that a land value tax encourages more development closer to preexisting development than farther from preexisting development. Specifically, the marginal effects of a land value tax on the probability of land development is hypothesized to be greater in areas around preexisting development than in areas more distant from preexisting development. The findings show that the marginal effects of a land value tax on the probability of developing parcels that neighbored previously developed parcels was greater than the probability of developing parcels that did not neighbor previously developed parcels. This finding suggests that land value taxation could be used to design compact development strategies that address sprawling development.Land value tax, Land development model, Urban sprawl, Land Economics/Use, Community/Rural/Urban Development,
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