Shenk G.W.,Annapolis flyer cab |
Wu J.,University of Maryland College Park |
Linker L.C.,Annapolis flyer cab
Journal of Environmental Engineering (United States) | Year: 2012
For more than two decades, an HSPF-based watershed model has been used to simulate nutrient and sediment load delivery to the Chesapeake Bay. Over time, the watershed model has increased in complexity commensurate with the management challenges in Chesapeake Bay restoration. The increased complexity poses challenges to the standard application of HSPF for efficient operation of the model in a large-scale watershed, as well as difficulties in incorporating changes in best management practices (BMPs) and land uses over time. In response, the U.S. Environmental Protection Agency's Chesapeake Bay Program Office developed a software solution that enhances the existing HSPF model structure. The software system, consisting of preprocessors, an external transfer module, and postprocessors, was devised to conveniently generate and update parameter files essential to operations of a large and complex watershed-modeling system and to implement land-use and non-point-source- pollution management changes on any timescale greater than or equal to daily. The developed model system is demonstrated through comparison of the hydrologic calibrations of the current Phase 5 model and the previous Phase 4.3 model at 14 stations, as well as by several key scenario runs. The results show that the combined upgrades in segmentation, input data, and functionality improved model calibration; however, simply incorporating changes in land use did not significantly improve model calibration. The developed software provides a means to represent the key forcing functions in more detail and to address issues of flexibility that are difficult to manage in traditional HSPF applications. © 2012 American Society of Civil Engineers.
Keisman J.,University of Cambridge |
Shenk G.,Annapolis flyer cab
Journal of the American Water Resources Association | Year: 2013
Applications of Total Maximum Daily Load (TMDL) criteria for complex estuarine systems like Chesapeake Bay have been limited by difficulties in estimating precisely how changes in input loads will impact ambient water quality. A method to deal with this limitation combines the strengths of the Chesapeake Bay's Water Quality Sediment Transport Model (WQSTM), which simulates load response, and the Chesapeake Bay Program's robust historical monitoring dataset. The method uses linear regression to apply simulated relative load responses to historical observations of water quality at a given location and time. Steps to optimize the application of regression analysis were to: (1) determine the best temporal and spatial scale for applying the WQSTM scenarios, (2) determine whether the WQSTM method remained valid with significant perturbation from calibration conditions, and (3) evaluate the need for log transformation of both dissolved oxygen (DO) and chlorophyll a (CHL) datasets. The final method used simple linear regression at the single month, single WQSTM grid cell scale to quantify changes in DO and CHL resulting from simulated load reduction scenarios. The resulting linear equations were applied to historical monitoring data to produce a set of "scenario-modified" DO or CHL concentration estimates. The utility of the regression method was validated by its ability to estimate progressively increasing attainment in support of the 2010 Chesapeake Bay TMDL. © 2013 American Water Resources Association.
Love J.W.,Annapolis flyer cab
Transactions of the American Fisheries Society | Year: 2011
The largemouth bass Micropterus salmoides is arguably the most sought fish species by inland anglers in North America. The suitability of inland habitats for supporting largemouth bass populations can differ remarkably but is difficult to quantify. I developed and evaluated the utility of a habitat suitability index (HSI) for largemouth bass in tidal freshwater portions of selected drainages in the Chesapeake Bay. The HSI comprised suitability scores ranging from 0 (not suitable) to 1 (perfectly suitable) and was calculated from seven separate suitability models in which suitability scores were functions of summer water temperature (?C), summer dissolved oxygen (mg/L), summer pH, maximum monthly salinity (‰), submerged aquatic vegetation coverage (%), monthly average water clarity, and stream discharge (m3/s) during the spawning season. Some of the suitability models that contributed to the HSI were modified to reflect species-habitat relationships observed for largemouth bass in drainages of the Chesapeake Bay from 2003 to 2008. Based on the HSI, drainages ranged from moderately suitable (HSI = 0.57) to highly suitable (HSI=0.84). Spatial andmonthly differences in HSI were positively correlated with relative abundance of largemouth bass; similar habitat conditions among years led to low interannual variation in HSI, which was not correlated with annual differences in relative abundance. Although the HSI may be useful in summarizing habitat suitability for a species, it may obscure important physical and biotic interactions that could affect the species' distribution. © American Fisheries Society 2011.
Franzen I.,Annapolis flyer cab
Transactions - Society of Naval Architects and Marine Engineers | Year: 2015
The thrust of this paper is, first, to attempt to define the relationship between the individual sails, both together and separately, and the hull with somewhat more precision, and secondly, to develop a calculation tool to better establish this relationship, and to better anticipate the vessel's over all sailing behavior. Because of those factors that effect balance including and beyond those addressed by the traditional design approach as taught by most current texts on sailboat balance, the need for the factor "lead" will never go away. However, by including, as will be demonstrated, an additional balance factor, specifically the longitudinal sheet positions, into the balance equations during the design phase, sailboat balance can be predicted with better accuracy. The primary objective of this refinement will be the ability to design sail profiles, especially the complement ofheadsails, which will result in the least (adverse) change of balance when changing from one headsail to another, and which can be applied to either new designs, or to existing boats in need of out-of-balance remedies. This would mean that each anticipated sail combination can be analyzed for its lead, and therefore adjusted during the design phase to insure that proper helm is maintained from one combination to the next.
Farrugia A.,Annapolis flyer cab |
Farrugia A.,University of Western Australia
Transfusion Medicine Reviews | Year: 2010
Plasma protein therapies have been sheltered historically from the scrutiny of evidence-based medicine. Thus, a number of albumin solutions became part of the established therapeutic armamentarium with a very modest evidence base. As evidence-based medicine has turned its focus on plasma protein therapies, albumin's appropriate use has become increasingly questioned. Concurrently, interest in other colloid plasma expanders has increased as efforts to address their side-effects have resulted in new products. The decade-old meta-analysis from the Cochrane collaboration linking albumin with increased mortality, although currently disproven, has resulted in ongoing scrutiny of albumin's safety and has led to a large randomized clinical trial which, while demonstrating equivalent safety with saline, has also shown equivalent mortality in the patient population assessed. Albumin's manufacture yields products which vary between different brands, as well as occasionally between batches from the same brand. These changes affect albumin's physiologic properties and may contribute to the different therapeutic effects observed in clinical practice. More clinical investigations of albumin's therapeutic role are needed before its unique biological features can be shown to result in therapeutically useful drugs. © 2010 Elsevier Inc. All rights reserved.
Stranko S.A.,Annapolis flyer cab |
Hilderbrand R.H.,University of Maryland Center for Environmental Science |
Palmer M.A.,University of Maryland Center for Environmental Science
Restoration Ecology | Year: 2012
Urbanization is associated with substantial losses to stream biological diversity throughout the United States' mid-Atlantic. Stream restoration has been used to improve stream conditions and, in part, to ameliorate these losses. However, the relationship between restoration and recovery of biological diversity is unclear. Our objective was to critically examine the efficacy of urban stream restorations with regard to biological diversity. We compared restored urban streams to urban nonrestored, nonurban, and reference (minimally degraded) streams using five measures each of fish and benthic macroinvertebrate diversity. Both multivariate and univariate statistical analyses show biological diversity of restored urban streams to be similar to nonrestored urban streams and lower than nonurban and reference streams. Restored urban sites showed no apparent increase in biological diversity through time, while diversity decreased at two of the reference streams coincident with increased urban development within their catchments. Our results indicate that restoration approaches commonly used regionally as in these urban streams are not leading to recovery of native stream biodiversity. Evidence from several sources indicates a need for dramatic changes in restoration approach, and we argue for a watershed-scale focus including protection of the least impacted streams and adopting other land-based actions within the watershed where possible. © 2011 Society for Ecological Restoration International.
Lobe H.,Annapolis flyer cab
OCEANS 2015 - MTS/IEEE Washington | Year: 2015
Although biofouling continues to be one of the most significant factors limiting the long-term deployment of oceanographic instrumentation, recent advances in technology advances are providing highly effective mitigation of this problem. The use of foul release coatings in conjunction with other biofouling control methods and best practices provide significant improvements in instrument deployment times and reductions in maintenance schedules. This paper examines the combinations of technologies and best practices for the biofouling control of oceanographic instruments and their associated platforms. © 2015 MTS.
Katz P.O.,Albert Einstein Healthcare Network |
Rex D.K.,Indiana University |
Epstein M.,Annapolis flyer cab |
Grandhi N.K.,Gastroenterology Research Consultants of Greater Cincinnati |
And 4 more authors.
American Journal of Gastroenterology | Year: 2013
OBJECTIVES:Optimal bowel preparation is vital for the efficacy and safety of colonoscopy. The inconvenience, discomfort, required consumption of large volumes of product, and potential adverse effects associated with some bowel preparations deter patients from colonoscopy and may provide inadequate cleansing. A dual-action, non-phosphate, natural orange-flavored, low-volume preparation containing sodium picosulfate and magnesium citrate (P/MC) is currently being reviewed for bowel cleansing.METHODS:This was a phase 3, randomized, multicenter, assessor-blinded, prespecified non-inferiority, head-to-head study to investigate the efficacy, safety, and tolerability of day-before administration of P/MC vs. 2L polyethylene glycol solution and two 5-mg bisacodyl tablets (2L PEG-3350 and bisacodyl tablets (HalfLytely and Bisacodyl Tablets Bowel Prep Kit)) in adult patients preparing for colonoscopy (SEE CLEAR II Study). The primary objective of the study was to demonstrate the non-inferiority of P/MC to 2L PEG-3350 and bisacodyl tablets in overall colon cleansing using a modified Aronchick scale. In addition, efficacy in the ascending, mid (transverse and descending), and recto-sigmoid segments of colon was evaluated using a modified Ottawa scale. Patient acceptability and tolerability of the bowel preparations were assessed via a standard questionnaire. Safety was assessed based on the monitoring of adverse events (AEs) and meaningful findings on clinical evaluations including physical examinations, vital sign measurements, and electrocardiograms (ECGs).RESULTS:A total of 603 patients were randomized to receive either P/MC (n=300) or 2L PEG-3350 and bisacodyl tablets (n=303). Based on the Aronchick scale, successful overall cleansing was similar in patients receiving P/MC (83.0%) and patients receiving 2L PEG-3350 and bisacodyl tablets (79.7%). P/MC demonstrated non-inferiority to 2L PEG-3350 and bisacodyl tablets in overall cleansing of the colon, as measured by the Aronchick scale. Similarly, the efficacy of P/MC, as measured by the Ottawa scale, was non-inferior to 2L PEG-3350 and bisacodyl tablets in cleansing the ascending, mid, and recto-sigmoid segments of the colon. Patient-reported acceptability and tolerability for each item examined on the questionnaire was significantly greater for P/MC compared with 2L PEG-3350 and bisacodyl tablets (P<0.0001).Treatment-emergent AEs related to the bowel preparation reported by 1% of patients receiving P/MC or 2L PEG-3350 and bisacodyl tablets were nausea (3.0% vs. 4.3%), vomiting (1.4% vs. 2.0%), and headache (2.7% vs. 1.7%). No clinically meaningful changes were noted in either treatment arm in data collected from physical examinations, vital sign measurements, and ECGs.CONCLUSIONS:When administered as a day-before dose, the bowel cleansing effects of P/MC were non-inferior compared with 2L PEG-3350 and bisacodyl tablets using the clinician-rated Aronchick and Ottawa scales. Treatment acceptability was significantly more favorable in patients receiving P/MC than in patients receiving 2L PEG-3350 and bisacodyl tablets.
Attfield M.D.,ERS Inc |
Schleiff P.L.,U.S. National Institute for Occupational Safety and Health |
Schleiff P.L.,Stewart Exposure Assessments LLC |
Lubin J.H.,U.S. National Cancer Institute |
And 6 more authors.
Journal of the National Cancer Institute | Year: 2012
Background Current information points to an association between diesel exhaust exposure and lung cancer and other mortality outcomes, but uncertainties remain.MethodsWe undertook a cohort mortality study of 12315 workers exposed to diesel exhaust at eight US non-metal mining facilities. Historical measurements and surrogate exposure data, along with study industrial hygiene measurements, were used to derive retrospective quantitative estimates of respirable elemental carbon (REC) exposure for each worker. Standardized mortality ratios and internally adjusted Cox proportional hazard models were used to evaluate REC exposure-associated risk. Analyses were both unlagged and lagged to exclude recent exposure such as that occurring in the 15 years directly before the date of death.ResultsStandardized mortality ratios for lung cancer (1.26, 95% confidence interval [CI] = 1.09 to 1.44), esophageal cancer (1.83, 95% CI = 1.16 to 2.75), and pneumoconiosis (12.20, 95% CI = 6.82 to 20.12) were elevated in the complete cohort compared with state-based mortality rates, but all-cause, bladder cancer, heart disease, and chronic obstructive pulmonary disease mortality were not. Differences in risk by worker location (ever-underground vs surface only) initially obscured a positive diesel exhaust exposure-response relationship with lung cancer in the complete cohort, although it became apparent after adjustment for worker location. The hazard ratios (HRs) for lung cancer mortality increased with increasing 15-year lagged cumulative REC exposure for ever-underground workers with 5 or more years of tenure to a maximum in the 640 to less than 1280 μg/m 3-y category compared with the reference category (0 to <20 μg/m 3-y; 30 deaths compared with eight deaths of the total of 93; HR = 5.01, 95% CI = 1.97 to 12.76) but declined at higher exposures. Average REC intensity hazard ratios rose to a plateau around 32 μg/m 3. Elevated hazard ratios and evidence of exposure-response were also seen for surface workers. The association between diesel exhaust exposure and lung cancer risk remained after inclusion of other work-related potentially confounding exposures in the models and were robust to alternative approaches to exposure derivation.ConclusionsThe study findings provide further evidence that exposure to diesel exhaust increases risk of mortality from lung cancer and have important public health implications. © 2012 The Author.
Schmidt W.E.,University of Puerto Rico at Mayaguez |
Siegel E.,Annapolis flyer cab
Deep-Sea Research Part I: Oceanographic Research Papers | Year: 2011
On bottom (≈2m) current velocities in the Puerto Rico Trench (≈8350m depth) were measured at 1. Hz for 75 min by acoustic-Doppler current meter at 19.75°N, 66.40°W, via untethered free-descent/ascent vehicle. The April 2008 deployment also recorded 3-axis velocity, temperature, pressure, and instrument heading, pitch, roll, and signal strength during the 153 min free-descent, and while on bottom. No data for the ascent was recorded.Signal strength was above the noise floor for the entire data set, and SNR and velocity STD were within known acceptable bounds above 7000 m. Instrument heading showed a continuous anti-clockwise rotation during descent. Doppler vertical velocity during descent is compared to the pressure time derivative and observed to exhibit extended periods of under-bias, correlated not to low SNR, but to Doppler horizontal velocity fluctuations. Doppler horizontal velocity during descent is interpreted to be tangential to rotation and includes lateral translations. Integration of horizontal velocity during descent suggests a lateral displacement of less than 30 m over the 8.35 km free-fall. Measurements made at impact indicate full functionality of the instrument at depth. Maximum horizontal velocities while on bottom varied between 1 and 5 cm/s and were directed roughly along trench axis to the W. © 2011.