Airborne sulfur trace species intercomparison campaign: Sulfur dioxide, dimethylsulfide, hydrogen sulfide, carbon disulfide, and carbonyl sulfide

Results from an airborne intercomparison of techniques to measure tropospheric levels of sulfur trace gases are presented. The intercomparison was part of the NASA Global Tropospheric Experiment (GTE) and was conducted during the summer of 1989. The intercomparisons were conducted on the Wallops Electra aircraft during flights from Wallops Island, Virginia, and Natal, Brazil. Sulfur measurements intercompared included sulfur dioxide (SO2), dimethylsulfide (DMS), hydrogen sulfide (H2S), carbon disulfide (CS2), and carbonyl sulfide (OCS). Measurement techniques ranged from filter collection systems with post-flight analyses to mass spectrometer and gas chromatograph systems employing various methods for measuring and identifying the sulfur gases during flight. Sampling schedules for the techniques ranged from integrated collections over periods as long as 50 minutes to one- to three-minute samples every ten or fifteen minutes. Several of the techniques provided measurements of more than one sulfur gas. Instruments employing different detection principles were involved in each of the sulfur intercomparisons. Also included in the intercomparison measurement scenario were a host of supporting measurements (i.e., ozone, nitrogen oxides, carbon monoxide, total sulfur, aerosols, etc.) for purposes of: (1) interpreting results (i.e., correlation of any noted instrument disagreement with the chemical composition of the measurement environment); and (2) providing supporting chemical data to meet CITE-3 science objectives of studying ozone/sulfur photochemistry, diurnal cycles, etc. The results of the intercomparison study are briefly discussed

ESTIMATED COSTS AND RETURNS FOR CATFISH FARMS WITH RECIRCULATING PONDS ALONG THE UPPER TEXAS COAST

Cost, returns, and economies of scale for small, medium and large catfish farms with recirculating ponds are presented for the upper Texas coast. Internal rates of return are 0.150, 0.183 and 0.219, respectively. Total investment is higher than farms with static ponds but investment per unit production capacity is 7 percent to 16 percent lower. Average total cost per pound is between $0.565 and$0.541, (11 percent –20 percent lower than farms using current technology). These results have implications for regional comparative advantage of catfish production as well as incentive for adoption of new technology in conventional ponds.Aquaculture, Catfish, Economics, Off-flavor, Livestock Production/Industries,

Assessment of upper tropospheric HOx sources over the tropical Pacific based on NASA GTE/PEM data: Net effect on HOx and other photochemical parameters

Data for the tropical upper troposphere (8-12 km, 20° N-20° S) collected during NASA's Pacific Exploratory Missions have been used to carry out a detailed examination of the photochemical processes controlling HOx (OH+HO2). Of particular significance is the availability of measurements of nonmethane hydrocarbons, oxygenated hydrocarbons (i.e., acetone, methanol, and ethanol) and peroxides (i.e., H2O2 and CH3OOH). These observations have provided constraints on model calculations permitting an assessment of the potential impact of these species on the levels of HOx, CH3O2, CH2O, as well as ozone budget parameters. Sensitivity calculations using a time-dependent photochemical box model show that when constrained by measured values of the above oxygenated species, model estimated HOx levels are elevated relative to unconstrained calculations. The impact of constraining these species was found to increase with altitude, reflecting the systematic roll-off in water vapor mixing ratios with altitude. At 11-12 km, overall increases in HOx approached a factor of 2 with somewhat larger increases being found for gross and net photochemical production of ozone. While significant, the impact on HOx due to peroxides appears to be less than previously estimated. In particular, observations of elevated H2O2 levels may be more influenced by local photochemistry than by convective transport. Issues related to the uncertainty in high-altitude water vapor levels and the possibility of other contributing sources of HOx are discussed. Finally, it is noted that the uncertainties in gas kinetic rate coefficients at the low temperatures of the upper troposphere and as well as OH sensor calibrations should be areas of continued investigation. Copyright 1999 by the American Geophysical Union

Measurements of pernitric acid at the South Pole during ISCAT 2000

The first measurements of pernitric acid at the South Pole were performed during the second Investigation of Sulfur Chemistry in the Antarctic Troposphere (ISCAT 2000). Observed HO2NO2 concentrations averaged 25 pptv. Simple steady-state calculations constrained by measurements show that the lifetime of pernitric acid was largely controlled by dry deposition, with thermal decomposition becoming increasingly important at warmer temperatures. We determined that the pernitric acid equilibrium constant is less uncertain than indicated in the literature. One consequence of pernitric acid deposition to the snow surface is that it is an important sink for both NOx and HOx. Another is that the photochemistry of HO2NO2 in the Antarctic snowpack may be a NOx source in addition to nitrate photolysis. This might be one of the important differences in snow photochemistry between the South Pole and warmer polar sites

Mapping the contribution of Allied Health Professions to the wider public health workforce : a rapid review of evidence-based interventions

Objectives: The objective was to identify a selection of the best examples of the public health contributions by Allied Health Professionals (AHPs) in order to encourage a wider awareness and participation from that workforce to public health practice. Study design: A mapping exercise was used to identify evidence-based interventions that could lead to health improvements across a population. Methods: A rapid review was undertaken to identify evidence, followed by a survey of Allied Health Profession (AHP) practitioners and an expert panel consensus method to select the examples of AHP public health interventions. Results: Nine evidence-based interventions are identified and selected as examples of current AHP good practice. These examples represent a contribution to public health and include screening interventions, secondary prevention and risk management. Conclusions: This study contributes to a strategy for AHPs in public health by appraising the effectiveness and impact of some exemplar AHP practices that contribute to health improvement. There is a need for AHPs to measure the impact of their interventions and to demonstrate evidence of outcomes at population level. Keywords: allied health professions; Applied Health Professionals; evidence-based practice; health improvement; public health; rapid revie

Actin and dynamin2 dynamics and interplay during clathrin-mediated endocytosis.

Clathrin-mediated endocytosis (CME) involves the recruitment of numerous proteins to sites on the plasma membrane with prescribed timing to mediate specific stages of the process. However, how choreographed recruitment and function of specific proteins during CME is achieved remains unclear. Using genome editing to express fluorescent fusion proteins at native levels and live-cell imaging with single-molecule sensitivity, we explored dynamin2 stoichiometry, dynamics, and functional interdependency with actin. Our quantitative analyses revealed heterogeneity in the timing of the early phase of CME, with transient recruitment of 2-4 molecules of dynamin2. In contrast, considerable regularity characterized the final 20 s of CME, during which ∼26 molecules of dynamin2, sufficient to make one ring around the vesicle neck, were typically recruited. Actin assembly generally preceded dynamin2 recruitment during the late phases of CME, and promoted dynamin recruitment. Collectively, our results demonstrate precise temporal and quantitative regulation of the dynamin2 recruitment influenced by actin polymerization

Early respiratory viral infections in infants with cystic fibrosis

This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Background Viral infections contribute to morbidity in cystic fibrosis (CF), but the impact of respiratory viruses on the development of airway disease is poorly understood. Methods Infants with CF identified by newborn screening were enrolled prior to 4 months of age to participate in a prospective observational study at 4 centers. Clinical data were collected at clinic visits and weekly phone calls. Multiplex PCR assays were performed on nasopharyngeal swabs to detect respiratory viruses during routine visits and when symptomatic. Participants underwent bronchoscopy with bronchoalveolar lavage (BAL) and a subset underwent pulmonary function testing. We present findings through 8.5 months of life. Results Seventy infants were enrolled, mean age 3.1 ± 0.8 months. Rhinovirus was the most prevalent virus (66%), followed by parainfluenza (19%), and coronavirus (16%). Participants had a median of 1.5 viral positive swabs (range 0–10). Past viral infection was associated with elevated neutrophil concentrations and bacterial isolates in BAL fluid, including recovery of classic CF bacterial pathogens. When antibiotics were prescribed for respiratory-related indications, viruses were identified in 52% of those instances. Conclusions Early viral infections were associated with greater neutrophilic inflammation and bacterial pathogens. Early viral infections appear to contribute to initiation of lower airway inflammation in infants with CF. Antibiotics were commonly prescribed in the setting of a viral infection. Future investigations examining longitudinal relationships between viral infections, airway microbiome, and antibiotic use will allow us to elucidate the interplay between these factors in young children with CF

Evaluation of Antibiotic Properties of Diarylhydrazones, Diaryl Schiff-bases and Their Precursors

Parallel with the advancements in medical techniques and treatments, the microorganisms that we are constantly battling against are also evolving. Bacterial evolution is leading to an increasing number of antibiotic resistant strains of bacteria. As the bacteria evolve, the antibiotics that are currently in use to combat bacterial diseases are becoming ineffective. FDA approval of new antibacterial agents decreased drastically over the past decade. Thus the design and synthesis of new classes of antibacterial agents, possibly with structures unrelated to the current antibiotics, as the next generation antibacterial agents is highly desirable. In the current work the antimicrobial effect of an extended library of about 80 diarylhydrazones, related diaryl Schiff-bases and their precursor compounds, aryl-carbonyl compounds and phenylhydrazines have been evaluated against Escherichia coli, Micrococcus luteus and Staphylococcus aureus strains of bacteria. All compounds have been properly purified by recrystallization or column chromatography. The products were characterized by mass spectrometry and 1H, 13C and, when applicable, 19F NMR spectroscopy. While the diarylhydrazones and diaryl Schiff-bases were chosen due to their general biological activity, the carbonyl compounds and phenylhydrazines, that are their precursor compounds, were screened as possible metabolic products. Independent hydrolysis and mass spectrometric studies were also carried out under the generic assay conditions in order to determine the stability of the screened diarylhydrazones and Schiff-bases. The compounds have been tested in standard cytotoxicity assays using Escherichia coli, Micrococcus luteus and Staphylococcus aureus strains. It was observed that the diarylhydrazones showed considerable activity against all three bacterial strains, while the diaryl Schiff-bases exhibited moderate to weak activity. The precursor compounds appeared to be inactive against the bacteria. The stability studies also indicated that the hydrazones as well as the Schiff-bases remained stable under the assay conditions

A Bayesian Approach to the Detection Problem in Gravitational Wave Astronomy

The analysis of data from gravitational wave detectors can be divided into three phases: search, characterization, and evaluation. The evaluation of the detection - determining whether a candidate event is astrophysical in origin or some artifact created by instrument noise - is a crucial step in the analysis. The on-going analyses of data from ground based detectors employ a frequentist approach to the detection problem. A detection statistic is chosen, for which background levels and detection efficiencies are estimated from Monte Carlo studies. This approach frames the detection problem in terms of an infinite collection of trials, with the actual measurement corresponding to some realization of this hypothetical set. Here we explore an alternative, Bayesian approach to the detection problem, that considers prior information and the actual data in hand. Our particular focus is on the computational techniques used to implement the Bayesian analysis. We find that the Parallel Tempered Markov Chain Monte Carlo (PTMCMC) algorithm is able to address all three phases of the anaylsis in a coherent framework. The signals are found by locating the posterior modes, the model parameters are characterized by mapping out the joint posterior distribution, and finally, the model evidence is computed by thermodynamic integration. As a demonstration, we consider the detection problem of selecting between models describing the data as instrument noise, or instrument noise plus the signal from a single compact galactic binary. The evidence ratios, or Bayes factors, computed by the PTMCMC algorithm are found to be in close agreement with those computed using a Reversible Jump Markov Chain Monte Carlo algorithm.Comment: 19 pages, 12 figures, revised to address referee's comment