Short-term methane emissions from 2 dairy farms in California estimated by different measurement techniques and US Environmental Protection Agency inventory methodology: A case study.

Reported estimates of CH4 emissions from ruminants and manure management are up to 2 times higher in atmospheric top-down calculations than in bottom-up (BU) inventories. We explored this discrepancy by estimating CH4 emissions of 2 dairy facilities in California with US Environmental Protection Agency (US EPA) methodology, which is used for BU inventories, and 3 independent measurement techniques: (1) open-path measurements with inverse dispersion modeling (hereafter open-path), (2) vehicle measurements with tracer flux ratio method, and (3) aircraft measurements with the closed-path method. All 3 techniques were used to estimate whole-facility CH4 emissions during 3 to 6 d per farm in the summer of 2016. In addition, open-path was used to estimate whole-facility CH4 emissions over 13 to 14 d per farm in the winter of 2017. Our objectives were to (1) compare whole-facility CH4 measurements utilizing the different measurement techniques, (2) compare whole-facility CH4 measurements to US EPA inventory methodology estimates, and (3) compare CH4 emissions between 2 dairies. Whole-facility CH4 estimates were similar among measurement techniques. No seasonality was detected for CH4 emissions from animal housing, but CH4 emissions from liquid manure storage were 3 to 6 times greater during the summer than during the winter measurement periods. The findings confirm previous studies showing that whole-facility CH4 emissions need to be measured throughout the year to estimate and evaluate annual inventories. Open-path measurements for liquid manure storage emissions were similar to monthly US EPA estimates during the summer, but not during the winter measurement periods. However, the numerical difference was relatively small considering yearly emission estimates. Manure CH4 emissions contributed 69 to 79% and 26 to 47% of whole-facility CH4 emissions during the summer and winter measurement periods, respectively. Methane yields from animal housing were similar between farms (on average 20.9 g of CH4/kg of dry matter intake), but CH4 emissions normalized by volatile solids (VS) loading from liquid manure storage (g of CH4 per day/kg of VS produced by all cattle per day) at 1 dairy were 1.7 and 3.5 times greater than at the other during the summer (234 vs. 137 g of CH4/kg of VS) and winter measurement periods (78 vs. 22 g of CH4/kg of VS), respectively. We attributed much of this difference to the proportion of manure stored in liquid (anaerobic) form, and suggest that manure management practices that reduce the amount of manure solids stored in liquid form could significantly reduce dairy CH4 emissions.

New Approaches to Measuring Sticky Molecules: Improvement of Instrumental Response Times Using Active Passivation.

A novel method has been developed to improve sampling system response times for nominally "sticky" molecules such as HNO3 and NH3. The method reported here makes use of active, continuous passivation, where the instrument interfaces are continuously exposed to 0.01-1 ppm of fluorinated acidic or basic surfactants. To reduce HNO3 response times, perfluoroheptanoic acid and perfluorobutanesulfonic acid vapors are evaluated as passivation species. 1H,1H-perfluorooctylamine is used to improve NH3 response times. The resulting time responses using the perfluoroalkanoic acids are on the order of 0.4-0.7 s for a 75% quantitative recovery of HNO3, and 1-5 s for 90% recovery. Similar response time improvements are seen in detection of NH3 using perfluorooctylamine (<1 s for a 75% recovery, ∼ 2 s for 90% recovery). This generally applicable methodology significantly improves the capability of eddy covariance flux and real-time plume-based measurements of highly polar molecules that have historically been hampered by slow response times due to adsorption on sampling system surfaces. The utility of this approach is demonstrated by field measurements of HNO3 eddy covariance fluxes in a central U.S. prairie.

Vehicle emissions of radical precursors and related species observed in the 2009 SHARP campaign.

UNLABELLED: The 2009 Study of Houston Atmospheric Radical Precursors (SHARP) field campaign had several components that yielded information on the primary vehicular emissions of formaldehyde (HCHO) and nitrous acid (HONO), in addition to many other species. Analysis of HONO measurements at the Moody Tower site in Houston, TX, yielded emission ratios of HONO to the vehicle exhaust tracer species NOx and CO of 14 pptv/ppbv and 2.3 pptv/ppbv, somewhat smaller than recently published results from the Galleria site, although evidence is presented that the Moody Tower values should be upper limits to the true ratios of directly emitted HONO, and are consistent with ratios used in current standard emissions models. Several other Moody Tower emission ratios are presented, in particular a value for HCHO/CO of 2.4 pptv/ppbv. Considering only estimates of random errors, this would be significantly lower than a previous value, though the small sample size and possible systematic differences should be taken into account. Emission factors for CO, NOx, and HCHO, as well as various volatile organic compounds (VOCs), were derived from mobile laboratory measurements both in the Washburn Tunnel and in on-road exhaust plume observations. These two sets of results and others reported in the literature all agree well, and are substantially larger than the CO, NOx, and HCHO emission factors derived from the emission ratios reported from the Galleria site. IMPLICATIONS: Emission factors for the species measured in the various components of the 2009 SHARP campaign in Houston, TX, including HCHO, HONO, CO, CO2, nitrogen oxides, and VOCs, are needed to support regional air quality monitoring. Components of the SHARP campaign measured these species in several different ways, each with their own potential for systematic errors and differences in vehicle fleets sampled. Comparisons between data sets suggest that differences in sampling place and time may result in quite different emission factors, while also showing that different vehicle mixes can yield surprisingly similar emission factors.

Atmospheric measurements of the physical evolution of aircraft exhaust plumes.

Drawing from a series of field measurement activities including the Alternative Aviation Fuels Experiments (AAFEX1 and AAFEX2), we present experimental measurements of particle number, size, and composition-resolved mass that describe the physical and chemical evolution of aircraft exhaust plumes on the time scale of 5 s to 2-3 min. As the plume ages, the particle number emission index initially increases by a factor of 10-50, due to gas-to-particle formation of a nucleation/growth mode, and then begins to fall with increased aging. Increasing the fuel sulfur content causes the initial increase to occur more rapidly. The contribution of the nucleation/growth mode to the overall particle number density is most pronounced at idle power and decreases with increasing engine power. Increasing fuel sulfur content, but not fuel aromatic content causes the nucleation/growth mode to dominate the particle number emissions at higher powers than for a fuel with "normal" sulfur and aromatic content. Particle size measurements indicate that the observed particle number emissions trends are due to continuing gas-to-particle conversion and coagulation growth of the nucleation/growth mode particles, processes which simultaneously increase particle mass and reduce particle number density. Measurements of nucleation/growth mode mass are consistent with the interpretation of particle number and size data and suggest that engine exit plane measurements may underestimate the total particle mass by as much as a factor of between 5 and 10.

Adaptation of a proton transfer reaction mass spectrometer instrument to employ NO+ as reagent ion for the detection of 1,3-butadiene in the ambient atmosphere.

A proton transfer reaction mass spectrometer (PTR-MS) instrument was adapted to employ NO+ as a chemical reagent ion without any hardware changes by switching the reagent ion source gas from water vapor to dry air. Ionization of dry air within the hollow cathode ion source generates a very intense source of NO+ with only a minor impurity of NO2+. The intensities of the primary NO+ reagent ion and the unwanted impurity NO2+ are controllable and dependent on the operational conditions of the hollow cathode ion source. Ion source tuning parameters are described, which maintain an intense source of NO+ while keeping the impurity NO2+ signal to less than 2% of the total reagent ion intensity. This method is applied to the detection of 1,3-butadiene. NO+ reacts efficiently with 1,3-butadiene via a charge exchange reaction to produce only the molecular ion, which is detected at m/z 54. Detection sensitivities of the order of 45 pptv for a 1-s measurement of 1,3-butadiene are demonstrated. We present the first real-time on-line sub parts per billion measurement of 1,3-butadiene in the ambient atmosphere. The only likely interference is from 1,2-butadiene. Concurrent measurements of benzene are provided and suggest that the vehicular emissions are the predominant source of 1,3-butadiene in a suburban Boston area monitoring location.

Using observations and source specific model tracers to characterize pollutant transport during FRAPPÉ and DISCOVER-AQ.

Transport is a key parameter in air quality research and plays a dominant role in the Colorado Northern Front Range Metropolitan Area (NFRMA), where terrain induced flows and recirculation patterns can lead to vigorous mixing of different emission sources. To assess different transport processes and their connection to air quality in the NFRMA during the FRAPPÉ and DISCOVER-AQ campaigns in summer 2014, we use the Weather Research and Forecasting Model with inert tracers. Overall, the model represents well the measured winds and the inert tracers are in good agreement with observations of comparable trace gas concentrations. The model tracers support the analysis of surface wind and ozone measurements and allow for the analysis of transport patterns and interactions of emissions. A main focus of this study is on characterizing pollution transport from the NFRMA to the mountains by mountain-valley flows and the potential for recirculating pollution back into the NFRMA. One such event on 12 August 2014 was well captured by the aircraft and is studied in more detail. The model represents the flow conditions and demonstrates that during upslope events, frequently there is a separation of air masses that are heavily influenced by oil and gas emissions to the North and dominated by urban emissions to the South. This case study provides evidence that NFRMA pollution not only can impact the nearby Foothills and mountain areas to the East of the Continental Divide, but that pollution can "spill over" into the valleys to the West of the Continental Divide.

Overview of surface measurements and spatial characterization of submicrometer particulate matter during the DISCOVER-AQ 2013 campaign in Houston, TX.

The sources of submicrometer particulate matter (PM1) remain poorly characterized in the industrialized city of Houston, TX. A mobile sampling approach was used to characterize PM1 composition and concentration across Houston based on high-time-resolution measurements of nonrefractory PM1 and trace gases during the DISCOVER-AQ Texas 2013 campaign. Two pollution zones with marked differences in PM1 levels, character, and dynamics were established based on cluster analysis of organic aerosol mass loadings sampled at 16 sites. The highest PM1 mass concentrations (average 11.6 ± 5.7 µg/m3) were observed to the northwest of Houston (zone 1), dominated by secondary organic aerosol (SOA) mass likely driven by nighttime biogenic organonitrate formation. Zone 2, an industrial/urban area south/east of Houston, exhibited lower concentrations of PM1 (average 4.4 ± 3.3 µg/m3), significant organic aerosol (OA) aging, and evidence of primary sulfate emissions. Diurnal patterns and backward-trajectory analyses enable the classification of airmass clusters characterized by distinct PM sources: biogenic SOA, photochemical aged SOA, and primary sulfate emissions from the Houston Ship Channel. Principal component analysis (PCA) indicates that secondary biogenic organonitrates primarily related with monoterpenes are predominant in zone 1 (accounting for 34% of the variability in the data set). The relevance of photochemical processes and industrial and traffic emission sources in zone 2 also is highlighted by PCA, which identifies three factors related with these processes/sources (~50% of the aerosol/trace gas concentration variability). PCA reveals a relatively minor contribution of isoprene to SOA formation in zone 1 and the absence of isoprene-derived aerosol in zone 2. The relevance of industrial amine emissions and the likely contribution of chloride-displaced sea salt aerosol to the observed variability in pollution levels in zone 2 also are captured by PCA. IMPLICATIONS: This article describes an urban-scale mobile study to characterize spatial variations in submicrometer particulate matter (PM1) in greater Houston. The data set indicates substantial spatial variations in PM1 sources/chemistry and elucidates the importance of photochemistry and nighttime oxidant chemistry in producing secondary PM1. These results emphasize the potential benefits of effective control strategies throughout the region, not only to reduce primary emissions of PM1 from automobiles and industry but also to reduce the emissions of important secondary PM1 precursors, including sulfur oxides, nitrogen oxides, ammonia, and volatile organic compounds. Such efforts also could aid in efforts to reduce mixing ratios of ozone.

Tetralogy of Fallot: selective staged management.

One hundred twenty-four patients with tetralogy of Fallot have undergone either primary total repair (61), shunt and later repair (30), or an initial shunt (33). The mean ratio of pulmonary anulus to descending thoracic aorta increased from 0.80 +/- 0.25 before the shunt to 1.22 +/- 0.26 before the repair (p less than 0.0001). The mean ratio in the primary repair group was 1.23 +/- 0.25. A transannular patch was necessary in only six of 91 patients (6.6%). Postrepair right ventricular/left ventricular pressure ratio averaged 0.50 +/- 0.11 in the shunt plus repair group and 0.43 +/- 0.12 in the primary repair group. Only four patients had a right ventricular/left ventricular pressure ratio less than 0.65. A significant inverse linear relationship existed between this ratio and the pulmonary anulus size measured at operation and normalized for the patient's height (p less than 0.01). Postoperative complications occurred in 21% of patients after a shunt and 20% of patients after open heart repair. The early mortality was 0.8% (1/124). An initial shunt in patients with a small pulmonary anulus can result in an increased anulus size and better hemodynamic result with frequent avoidance of a transannular patch. Staged repair may result in improved overall mortality rates.

Intermediate-term results in pediatric aortic valve replacement.

BACKGROUND: Aortic valve replacement (AVR) in children is now more commonly performed with human tissue valves. METHODS: The results of 100 consecutive pediatric AVRs (50 mechanical, 50 human) were reviewed. RESULTS: There were five perioperative deaths in the mechanical group and one in the human group (p = 0.2). Late complications in the mechanical group included 4 late deaths, 2 cases of endocarditis, 3 thromboembolic complications, and 10 reoperations on the aortic valve. In the human group, there were no late deaths, 2 reoperations for allograft aortic valve deterioration (both in Marfan's patients), and 1 reoperation for allograft pulmonary valve stenosis. Four-year actuarial survival was 83% in the mechanical group and 98% in the human group (p = 0.02). Four-year actuarial survival free of all valve-related complications was 61% in the mechanical group and 88% in the human group (p = 0.008). CONCLUSIONS: Human valves in children requiring AVR provide superior intermediate-term survival and freedom from valve-related complications compared to mechanical valves. Marfan's syndrome may represent a rare remaining contraindication for human AVR in children.

D-2-hydroxyglutaric aciduria: hypotonia, cortical blindness, seizures, cardiomyopathy, and cylindrical spirals in skeletal muscle.

An infant girl was demonstrated to have D-2-hydroxyglutaric aciduria, the fifth case described and the first with muscle biopsy of this rare organic aciduria that differs clinically and genetically from the more common L-2-hydroxyglutaric aciduria. Her clinical features included mildly dysmorphic facies, developmental delay, generalized hypotonia, myoclonic seizures, cortical blindness, and dilated cardiomyopathy requiring treatment. Muscle biopsy demonstrated only excessive glycogen histochemically, but ultrastructural examination revealed subsarcolemmal cylindrical spirals and normal mitochondria. Because of the metabolism of D-2-hydroxyglutaric aciduria, we regard valproic acid as contraindicated in the treatment of epilepsy in this disease.

Pediatric critical care nurses' knowledge of cardiac dysrhythmias.

OBJECTIVE: To describe pediatric critical care nurses' knowledge of dysrhythmias in critically ill pediatric patients and relate this knowledge level to certain demographic variables (education, nursing experience, certification, supplemental training, area of employment and geographic region of residence). DESIGN: A descriptive survey. SETTING: American Association of Critical-Care Nurses' 19 geographic regions of the United States. PARTICIPANTS: Of 1000 questionnaires mailed to pediatric critical care nurses who were members of the American Association of Critical-Care Nurses in 1991, 356 responses were received (a response rate of 36%). INTERVENTION: A criterion-referenced, self-administered test regarding pediatric dysrhythmias and a demographic sheet randomly mailed to 1000 pediatric critical care nurses. Test results were analyzed and compared with demographic variables. RESULTS: The mean total test score was 66%. Significantly higher total test scores and selected subtest scores were demonstrated in relationship to the following variables: increased age; certification in pediatric advanced life support, advanced cardiac life support or adult critical care; increased years of adult critical care experience; advanced dysrhythmia courses and dysrhythmia self-study; and perceived knowledge level above that of the advanced beginner. CONCLUSIONS: Pediatric critical care nurses' overall knowledge of dysrhythmias was low. Knowledge strengths included recognition of basic and life-threatening dysrhythmias and calculation of basic ECG measurements. Knowledge deficits included importance of sinus bradycardia in the neonate, appropriate intervention for life-threatening dysrhythmias and calculation of an irregular heart rate. These deficits should be considered when planning continuing education programs for pediatric critical care nurses.

Short-term variation in near-highway air pollutant gradients on a winter morning.

Quantification of exposure to traffic-related air pollutants near highways is hampered by incomplete knowledge of the scales of temporal variation of pollutant gradients. The goal of this study was to characterize short-term temporal variation of vehicular pollutant gradients within 200-400 m of a major highway (>150 000 vehicles/d). Monitoring was done near Interstate 93 in Somerville (Massachusetts) from 06:00 to 11:00 on 16 January 2008 using a mobile monitoring platform equipped with instruments that measured ultrafine and fine particles (6-1000 nm, particle number concentration (PNC)); particle-phase (>30 nm) [Formula: see text], [Formula: see text], and organic compounds; volatile organic compounds (VOCs); and CO(2), NO, NO(2), and O(3). We observed rapid changes in pollutant gradients due to variations in highway traffic flow rate, wind speed, and surface boundary layer height. Before sunrise and peak traffic flow rates, downwind concentrations of particles, CO(2), NO, and NO(2) were highest within 100-250 m of the highway. After sunrise pollutant levels declined sharply (e.g., PNC and NO were more than halved) and the gradients became less pronounced as wind speed increased and the surface boundary layer rose allowing mixing with cleaner air aloft. The levels of aromatic VOCs and [Formula: see text], [Formula: see text] and organic aerosols were generally low throughout the morning, and their spatial and temporal variations were less pronounced compared to PNC and NO. O(3) levels increased throughout the morning due to mixing with O(3)-enriched air aloft and were generally lowest near the highway reflecting reaction with NO. There was little if any evolution in the size distribution of 6-225 nm particles with distance from the highway. These results suggest that to improve the accuracy of exposure estimates to near-highway pollutants, short-term (e.g., hourly) temporal variations in pollutant gradients must be measured to reflect changes in traffic patterns and local meteorology.

Analysis of health education sections of health systems plans.

Health Systems Agencies are required by federal guidelines to plan for and provide educational opportunities for residents of their health service areas. A study was conducted of 9 health education components of health systems plans developed by HSAs in Region III. The health education plans were analyzed and scored using the "Health Education Plan Scorecard" developed by Sullivan and adapted by the present authors. Specifically this modified scorecard consists of eight dimensions of the health education planning process: Involvement, Principles and Practice of Health Education, Defining Problems, Setting Goals and Objectives, Recommending Actions, Obtaining Resources, Planning for Implementation, and Planning for Evaluation. Ratings were generally higher on the first five dimensions of the scorecard. The last three dimensions produced lower scores. The overall average score was 41 points out of a possible 100. Thus indicating the general overall low scores received by the plans. The paper includes 18 recommendations to HSAs for improving the quality of health education plans. A key recommendation is that the Health Education Plan Scorecard should be used as a guide and check list during the plan development process.

Genetic relationship between Sarcina ureae and members of the genus Bacillus.

Deoxyribonucleic acid-ribonucleic acid (DNA-RNA) and DNA-DNA hybridization studies were performed to determine the degree of genetic relatedness between Sarcina ureae and several members of the genus Bacillus. DNA-RNA hybridization showed a high degree of homology between S. ureae RNA and DNA from Bacillus species having a similar guanine plus cytosine content. The DNA from other genera of the family Micrococcaceae showed less homology with S. ureae RNA than did that of the Bacillus species tested; however, this homology was not found between the DNA of S. ureae and DNA from these Bacillus species or DNA from the other Micrococcaceae tested. Transformation with Bacillus DNA, infection with representatives from several major classes of Bacillus phages, and electrophoretic analysis of proteins in crude extracts of these strains were also attempted as a further test of the genetic relationship between the genera. These experiments did not support the belief that the two groups are closely related genetically.

Comparison of human tissues and mechanical prostheses for aortic valve replacement in children.

BACKGROUND: Aortic valve replacement in children is problematic because of complications of mechanical valves and uncertain outcomes associated with human valves. The results of pediatric aortic valve replacements over 5 years were reviewed. METHODS AND RESULTS: Mechanical valves were used exclusively during the first part of this series (n = 26). Thereafter, 25 consecutive aortic valve replacements were performed with autografts (n = 19) or allografts (n = 6). Allografts were used for Marfan's syndrome patients or those with unusable pulmonary valves. Among autograft/allograft recipients, 16 patients underwent 27 prior operations. In the mechanical group, 18 patients underwent 19 previous operations. Three patients in each group underwent a previous mechanical aortic valve replacement. Operative complications included two mild strokes and one pacemaker in the autograft/allograft group and three deaths and two pacemakers in the mechanical group. One autograft recipient required reoperation for pulmonary allograft stenosis. In the mechanical group, late complications included six cases of nonstructural degeneration and two cases of endocarditis, with three reoperations. Reoperation-free survival was 96% at 2 years in the autograft/allograft group and 80% at 2 years and 75% at 3 years in the mechanical group. Event-free survival was 96% at 2 years in the autograft/allograft group compared with 67% at 2 years and 49% at 3 years in the mechanical group (P < .05). CONCLUSIONS: The frequency of reoperations for mechanical aortic valve replacement has been surprisingly high. Aortic valve replacement in children with only autografts or allografts achieves good early results.

Pharmacokinetics and suggested oral dosing regimen of cisapride: a study in healthy cats.

The disposition of cisapride in seven healthy cats was determined following administration of either a single oral (2 mg/kg body weight) or intravenous (i.v.) (1 mg/kg body weight) dose. Cats were studied using a random crossover design. After administration of the oral capsule, maximum plasma drug concentration (Cmax) +/- standard deviation (SD) was 73.32 +/- 16.59 ng/ml, and bioavailability +/- SD was 29.0 +/- 22.6%. Following i.v. administration, extrapolated peak cisapride concentration (C0) +/- SD was 421.30 +/- 155.37 ng/ml, and clearance +/- SD was 15 +/- 0.67 ml/kg per minute. Elimination half-life (T1/2) was similar for both routes of administration (T1/2(oral) +/- SD was 5.27 +/- 3.16 hr, T1/2(i.v.) +/- SD was 5.19 +/- 3.77 hr). Adverse effects were not observed. Based on these results, a dose of 1 mg/kg body weight per os (PO) every eight hours or 1.5 mg/kg body weight every 12 hours is expected to result in plasma drug concentrations within the therapeutic ranges established for humans.