Method for distinctive estimation of stored acidity forms in acid mine wastes.

PubMed

Li, Jun; Kawashima, Nobuyuki; Fan, Rong; Schumann, Russell C; Gerson, Andrea R; Smart, Roger St C

2014-10-07

Jarosites and schwertmannite can be formed in the unsaturated oxidation zone of sulfide-containing mine waste rock and tailings together with ferrihydrite and goethite. They are also widely found in process wastes from electrometallurgical smelting and metal bioleaching and within drained coastal lowland soils (acid-sulfate soils). These secondary minerals can temporarily store acidity and metals or remove and immobilize contaminants through adsorption, coprecipitation, or structural incorporation, but release both acidity and toxic metals at pH above about 4. Therefore, they have significant relevance to environmental mineralogy through their role in controlling pollutant concentrations and dynamics in contaminated aqueous environments. Most importantly, they have widely different acid release rates at different pHs and strongly affect drainage water acidity dynamics. A procedure for estimation of the amounts of these different forms of nonsulfide stored acidity in mining wastes is required in order to predict acid release rates at any pH. A four-step extraction procedure to quantify jarosite and schwertmannite separately with various soluble sulfate salts has been developed and validated. Corrections to acid potentials and estimation of acid release rates can be reliably based on this method.

Toward a consistent model for strain accrual and release for the New Madrid Seismic Zone, central United States

USGS Publications Warehouse

Hough, S.E.; Page, M.

2011-01-01

At the heart of the conundrum of seismogenesis in the New Madrid Seismic Zone is the apparently substantial discrepancy between low strain rate and high recent seismic moment release. In this study we revisit the magnitudes of the four principal 1811–1812 earthquakes using intensity values determined from individual assessments from four experts. Using these values and the grid search method of Bakun and Wentworth (1997), we estimate magnitudes around 7.0 for all four events, values that are significantly lower than previously published magnitude estimates based on macroseismic intensities. We further show that the strain rate predicted from postglacial rebound is sufficient to produce a sequence with the moment release of one Mmax6.8 every 500 years, a rate that is much lower than previous estimates of late Holocene moment release. However, Mw6.8 is at the low end of the uncertainty range inferred from analysis of intensities for the largest 1811–1812 event. We show that Mw6.8 is also a reasonable value for the largest main shock given a plausible rupture scenario. One can also construct a range of consistent models that permit a somewhat higher Mmax, with a longer average recurrence rate. It is thus possible to reconcile predicted strain and seismic moment release rates with alternative models: one in which 1811–1812 sequences occur every 500 years, with the largest events being Mmax∼6.8, or one in which sequences occur, on average, less frequently, with Mmax of ∼7.0. Both models predict that the late Holocene rate of activity will continue for the next few to 10 thousand years.

Many Vulnerable or a Few Resilient Specimens? Finding the Optimal for Reintroduction/Restocking Programs

PubMed Central

Gil, María del Mar; Palmer, Miquel; Grau, Amalia; Balle, Salvador

2015-01-01

Most reintroduction and restocking programs consist of releasing captive-raised juveniles. The usefulness of these programs has been questioned, and therefore, quality control is advisable. However, evaluating restocking effectiveness is challenging because mortality estimation is required. Most methods for estimating mortality are based on tag recovery. In the case of fish, juveniles are tagged before release, and fishermen typically recover tags when fish are captured. The statistical models currently available for analyzing these data assume either constant mortality rates, fixed tag non-reporting rates, or both. Here, instead, we proposed a method that considers the mortality rate variability as a function of age/size of the released juveniles. Furthermore, the proposed method can disentangle natural from fishing mortality, analyzing the temporal distribution of the captures reported by fishermen from multiple release events. This method is demonstrated with a restocking program of a top-predator marine fish, the meagre (Argyrosomus regius), in the Balearic Islands. The estimated natural mortality just after release was very high for young fish (m 0 = 0.126 day-1 for fish 180 days old), but it was close to zero for large/old fish. These large/old fish were more resilient to wild conditions, although a long time was needed to achieve a relevant reduction in natural mortality. Conversely, these large/old fish were more vulnerable to fishing, creating a trade-off in survival. The release age that maximizes the number of survivors after, for example, one year at liberty was estimated to be 1,173 days. However, the production cost of relatively old fish is high, and only a few fish can be produced and released within a realistic budget. Therefore, in the case of the meagre, increasing the number of released fish will have no or scarce effects on restocking success. Conversely, it is advisable implement measures to reduce the high natural mortality of young juveniles and/or the length of time needed to improve fish resilience. PMID:26394242

The release rate of environmental DNA from juvenile and adult fish.

PubMed

Maruyama, Atsushi; Nakamura, Keisuke; Yamanaka, Hiroki; Kondoh, Michio; Minamoto, Toshifumi

2014-01-01

The environmental DNA (eDNA) technique is expected to become a powerful, non-invasive tool for estimating the distribution and biomass of organisms. This technique was recently shown to be applicable to aquatic vertebrates by collecting extraorganismal DNA floating in the water or absorbed onto suspended particles. However, basic information on eDNA release rate is lacking, despite it being essential for practical applications. In this series of experiments with bluegill sunfish (Lepomis macrochirus), we examined the effect of fish developmental stage on eDNA release rate. eDNA concentration reached equilibrium 3 days after the individual fish were introduced into the separate containers, enabling calculation of the eDNA release rate (copies h-1) from individual fish on the assumption that the number of eDNA released from the fish per unit time equals total degradation in the container (copies h-1). The eDNA release rate was 3-4 times higher in the adult (body weight: 30-75 g) than in the juvenile group (0.5-2.0 g). Such positive relationship between fish size and eDNA release rate support the possibility of biomass rather than density estimation using eDNA techniques. However, the eDNA release rate per fish body weight (copies h-1 g-1) was slightly higher in the juvenile than the adult group, which is likely because of the ontogenetic reduction in metabolic activity. Therefore, quantitative eDNA data should be carefully interpreted to avoid overestimating biomass when the population is dominated by juveniles, because the age structure of the focal population is often variable and unseen in the field. eDNA degradation rates (copies l-1 h-1), calculated by curve fitting of time-dependent changes in eDNA concentrations after fish removal, were 5.1-15.9% per hour (half-life: 6.3 h). This suggests that quantitative eDNA data should be corrected using a degradation curve attained in the target field.

Predicting Quarantine Failure Rates

PubMed Central

2004-01-01

Preemptive quarantine through contact-tracing effectively controls emerging infectious diseases. Occasionally this quarantine fails, however, and infected persons are released. The probability of quarantine failure is typically estimated from disease-specific data. Here a simple, exact estimate of the failure rate is derived that does not depend on disease-specific parameters. This estimate is universally applicable to all infectious diseases. PMID:15109418

Active adaptive management for reintroduction of an animal population

USGS Publications Warehouse

Runge, Michael C.

2013-01-01

Captive animals are frequently reintroduced to the wild in the face of uncertainty, but that uncertainty can often be reduced over the course of the reintroduction effort, providing the opportunity for adaptive management. One common uncertainty in reintroductions is the short-term survival rate of released adults (a release cost), an important factor because it can affect whether releasing adults or juveniles is better. Information about this rate can improve the success of the reintroduction program, but does the expected gain offset the costs of obtaining the information? I explored this question for reintroduction of the griffon vulture (Gyps fulvus) by framing the management question as a belief Markov decision process, characterizing uncertainty about release cost with 2 information state variables, and finding the solution using stochastic dynamic programming. For a reintroduction program of fixed length (e.g., 5 years of releases), the optimal policy in the final release year resembles the deterministic solution: release either all adults or all juveniles depending on whether the point estimate for the survival rate in question is above or below a specific threshold. But the optimal policy in the earlier release years 1) includes release of a mixture of juveniles and adults under some circumstances, and 2) recommends release of adults even when the point estimate of survival is much less than the deterministic threshold. These results show that in an iterated decision setting, the optimal decision in early years can be quite different from that in later years because of the value of learning. 

Detailed source term estimation of atmospheric release during the Fukushima Dai-ichi nuclear power plant accident by coupling atmospheric and oceanic dispersion models

NASA Astrophysics Data System (ADS)

Katata, Genki; Chino, Masamichi; Terada, Hiroaki; Kobayashi, Takuya; Ota, Masakazu; Nagai, Haruyasu; Kajino, Mizuo

2014-05-01

Temporal variations of release amounts of radionuclides during the Fukushima Dai-ichi Nuclear Power Plant (FNPP1) accident and their dispersion process are essential to evaluate the environmental impacts and resultant radiological doses to the public. Here, we estimated a detailed time trend of atmospheric releases during the accident by combining environmental monitoring data and coupling atmospheric and oceanic dispersion simulations by WSPEEDI-II (Worldwide version of System for Prediction of Environmental Emergency Dose Information) and SEA-GEARN developed by the authors. New schemes for wet, dry, and fog depositions of radioactive iodine gas (I2 and CH3I) and other particles (I-131, Te-132, Cs-137, and Cs-134) were incorporated into WSPEEDI-II. The deposition calculated by WSPEEDI-II was used as input data of ocean dispersion calculations by SEA-GEARN. The reverse estimation method based on the simulation by both models assuming unit release rate (1 Bq h-1) was adopted to estimate the source term at the FNPP1 using air dose rate, and air sea surface concentrations. The results suggested that the major release of radionuclides from the FNPP1 occurred in the following periods during March 2011: afternoon on the 12th when the venting and hydrogen explosion occurred at Unit 1, morning on the 13th after the venting event at Unit 3, midnight on the 14th when several openings of SRV (steam relief valve) were conducted at Unit 2, morning and night on the 15th, and morning on the 16th. The modified WSPEEDI-II using the newly estimated source term well reproduced local and regional patterns of air dose rate and surface deposition of I-131 and Cs-137 obtained by airborne observations. Our dispersion simulations also revealed that the highest radioactive contamination areas around FNPP1 were created from 15th to 16th March by complicated interactions among rainfall (wet deposition), plume movements, and phase properties (gas or particle) of I-131 and release rates associated with reactor pressure variations in Units 2 and 3.

Survival of captive-reared Hispaniolan Parrots released in Parque Nacional del Este, Dominican Republic

USGS Publications Warehouse

Collazo, J.A.; White, T.H.; Vilella, F.J.; Guerrero, S.A.

2003-01-01

We report first-year survival rates of 49 captive-reared Hispaniolan Parrots (Amazona ventralis) released in Parque Nacional del Este, Dominican Republic. Our goal was to learn about factors affecting postrelease survival. Specifically, we tested if survival was related to movements and whether modifying prerelease protocols influenced survival rates. We also estimated survival in the aftermath of Hurricane Georges (22 September 1998). Twenty-four parrots, fitted with radio-transmitters, were released between 14 September and 12 December 1997. Twenty-five more were released between 29 June and 16 September 1998. First-year survival rates were 30% in 1997 and 29% in 1998. Survival probability was related to bird mobility. In contrast to birds released in 1997, none of the 25 parrots released in 1998 suffered early postrelease mortality (i.e., 3-5 days after release). Two adjustments to prerelease protocols (increased exercise and reduced blood sampling) made in 1998 may have contributed to differences in mobility and survival between years. The reduction of early postrelease mortality in 1998 was encouraging, as was the prospect for higher first-year survival (e.g., 30% to 65%). Only one death was attributed to the immediate impact of the hurricane. Loss of foraging resources was likely a major contributor to ensuing mortality. Birds increased their mobility, presumably in search of food. Survival rates dropped 23% in only eight weeks posthurricane. This study underscores the value of standardized prerelease protocols, and of estimating survival and testing for factors that might influence it. Inferences from such tests will provide the best basis to make adjustments to a release program.

Spatially resolved heat release rate measurements in turbulent premixed flames

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayoola, B.O.; Kaminski, C.F.; Balachandran, R.

Heat release rate is a fundamental property of great importance for the theoretical and experimental elucidation of unsteady flame behaviors such as combustion noise, combustion instabilities, and pulsed combustion. Investigations of such thermoacoustic interactions require a reliable indicator of heat release rate capable of resolving spatial structures in turbulent flames. Traditionally, heat release rate has been estimated via OH or CH radical chemiluminescence; however, chemiluminescence suffers from being a line-of-sight technique with limited capability for resolving small-scale structures. In this paper, we report spatially resolved two-dimensional measurements of a quantity closely related to heat release rate. The diagnostic technique usesmore » simultaneous OH and CH{sub 2}O planar laser-induced fluorescence (PLIF), and the pixel-by-pixel product of the OH and CH{sub 2}O PLIF signals has previously been shown to correlate well with local heat release rates. Results from this diagnostic technique, which we refer to as heat release rate imaging (HR imaging), are compared with traditional OH chemiluminescence measurements in several flames. Studies were performed in lean premixed ethylene flames stabilized between opposed jets and with a bluff body. Correlations between bulk strain rates and local heat release rates were obtained and the effects of curvature on heat release rate were investigated. The results show that the heat release rate tends to increase with increasing negative curvature for the flames investigated for which Lewis numbers are greater than unity. This correlation becomes more pronounced as the flame gets closer to global extinction.« less

Improved estimates of environmental copper release rates from antifouling products.

PubMed

Finnie, Alistair A

2006-01-01

The US Navy Dome method for measuring copper release rates from antifouling paint in-service on ships' hulls can be considered to be the most reliable indicator of environmental release rates. In this paper, the relationship between the apparent copper release rate and the environmental release rate is established for a number of antifouling coating types using data from a variety of available laboratory, field and calculation methods. Apart from a modified Dome method using panels, all laboratory, field and calculation methods significantly overestimate the environmental release rate of copper from antifouling coatings. The difference is greatest for self-polishing copolymer antifoulings (SPCs) and smallest for certain erodible/ablative antifoulings, where the ASTM/ISO standard and the CEPE calculation method are seen to typically overestimate environmental release rates by factors of about 10 and 4, respectively. Where ASTM/ISO or CEPE copper release rate data are used for environmental risk assessment or regulatory purposes, it is proposed that the release rate values should be divided by a correction factor to enable more reliable generic environmental risk assessments to be made. Using a conservative approach based on a realistic worst case and accounting for experimental uncertainty in the data that are currently available, proposed default correction factors for use with all paint types are 5.4 for the ASTM/ISO method and 2.9 for the CEPE calculation method. Further work is required to expand this data-set and refine the correction factors through correlation of laboratory measured and calculated copper release rates with the direct in situ environmental release rate for different antifouling paints under a range of environmental conditions.

Using parentage analysis to estimate rates of straying and homing in Chinook salmon (Oncorhynchus tshawytscha).

PubMed

Ford, Michael J; Murdoch, Andrew; Hughes, Michael

2015-03-01

We used parentage analysis based on microsatellite genotypes to measure rates of homing and straying of Chinook salmon (Oncorhynchus tshawytscha) among five major spawning tributaries within the Wenatchee River, Washington. On the basis of analysis of 2248 natural-origin and 11594 hatchery-origin fish, we estimated that the rate of homing to natal tributaries by natural-origin fish ranged from 0% to 99% depending on the tributary. Hatchery-origin fish released in one of the five tributaries homed to that tributary at a far lower rate than the natural-origin fish (71% compared to 96%). For hatchery-released fish, stray rates based on parentage analysis were consistent with rates estimated using physical tag recoveries. Stray rates among major spawning tributaries were generally higher than stray rates of tagged fish to areas outside of the Wenatchee River watershed. Within the Wenatchee watershed, rates of straying by natural-origin fish were significantly affected by spawning tributary and by parental origin: progeny of naturally spawning hatchery-produced fish strayed at significantly higher rates than progeny whose parents were themselves of natural origin. Notably, none of the 170 offspring that were products of mating by two natural-origin fish strayed from their natal tributary. Indirect estimates of gene flow based on FST statistics were correlated with but higher than the estimates from the parentage data. Tributary-specific estimates of effective population size were also correlated with the number of spawners in each tributary. Published [2015]. This article is a U.S. Government work and is in the public domain in the USA.

Estimation of peacock bass (Cichla spp.) mortality rate during catch-release fishing employing different post-capture procedures.

PubMed

Barroco, L S A; Freitas, C E C; Lima, Á C

2018-05-01

The effect of catch-and-release fishing on the survival of peacock bass (Cichla spp.) was evaluated by comparing two types of artificial bait (jig and shallow-diver plugs) and two types of post-catch confinement. Two experiments were conducted during the periods January-February and October-November 2012 in the Unini River, a right-bank tributary of the Negro River. In total, 191 peacock bass were captured. Both groups of fish were subjected to experimental confinement (collective and individual) for three days. Additionally, 11 fish were tagged with radio transmitters for telemetry monitoring. Mortality rate was estimated as the percentage of dead individuals for each type of bait and confinement. For peacock bass caught with jig baits, mortality was zero. The corresponding figure for shallow-diver bait was 1.66% for fish in collective containment, 18.18% for fish monitored by telemetry and 0% for individuals confined individually. Our results show low post-release mortality rates for peacock bass. Furthermore, neither the type of confinement nor the type of bait had a statistically significant influence on mortality rates. While future studies could include other factors in the analysis, our results show that catch-and-release fishing results in low mortality rates.

An empirical model for dissolution profile and its application to floating dosage forms.

PubMed

Weiss, Michael; Kriangkrai, Worawut; Sungthongjeen, Srisagul

2014-06-02

A sum of two inverse Gaussian functions is proposed as a highly flexible empirical model for fitting of in vitro dissolution profiles. The model was applied to quantitatively describe theophylline release from effervescent multi-layer coated floating tablets containing different amounts of the anti-tacking agents talc or glyceryl monostearate. Model parameters were estimated by nonlinear regression (mixed-effects modeling). The estimated parameters were used to determine the mean dissolution time, as well as to reconstruct the time course of release rate for each formulation, whereby the fractional release rate can serve as a diagnostic tool for classification of dissolution processes. The approach allows quantification of dissolution behavior and could provide additional insights into the underlying processes. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparison of the Kinetic Rate Law Parameters for the Dissolution of Natural and Synthetic Autunite in the Presence of Aqueous Bicarbonate Ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.

2013-08-02

Bicarbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, bicarbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous bicarbonate concentration to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate (0.0005-0.003 M) under the pH range of 6-11 and a temperature range of 5-60oC. Consistentmore » with the results of previous investigation, the rate of uranium release exhibited minimal dependency on temperature; but were strongly dependent on pH. Increasing aqueous bicarbonate concentrations afforded comparable increases in the rate of release of uranium. Most notably under low pH conditions the aqueous bicarbonate resulted in up to 370 fold increases in the rate of uranium release in relative to the rate of uranium release in the absence of bicarbonate. However, the effect of aqueous bicarbonate on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release.« less

The association of the original OSHA chemical hazard communication standard with reductions in acute work injuries/illnesses in private industry and the industrial releases of chemical carcinogens.

PubMed

Oleinick, Arthur

2014-02-01

OSHA predicted the original chemical Hazard Communication Standard (HCS) would cumulatively reduce the lost workday acute injury/illness rate for exposure events by 20% over 20 years and reduce exposure to chemical carcinogens. JoinPoint trend software identified changes in the rate of change of BLS rates for days away from work for acute injuries/illnesses during 1992-2009 for manufacturing and nonmanufacturing industries for both chemical, noxious or allergenic injury exposure events and All other exposure events. The annual percent change in the rates was used to adjust observed numbers of cases to estimate their association with the standard. A case-control study of EPA's Toxic Release Inventory 1988-2009 data compared carcinogen and non-carcinogens' releases. The study estimates that the HCS was associated with a reduction in the number of acute injuries/illnesses due to chemical injury exposure events over the background rate in the range 107,569-459,395 (Hudson method/modified BIC model) depending on whether the HCS is treated as a marginal or sole factor in the decrease. Carcinogen releases have declined at a substantially faster rate than control non-carcinogens. The previous HCS standard was associated with significant reductions in chemical event acute injuries/illnesses and chemical carcinogen exposures. © 2013 Wiley Periodicals, Inc.

In vivo release of levonorgestrel from Sino-implant (II) — an innovative comparison of explant data.

PubMed

Callahan, Rebecca L; Taylor, Douglas; Jenkins, David W; Owen, Derek H; Cheng, Linan; Cancel, Aida M; Dorflinger, Laneta J; Steiner, Markus J

2015-10-01

Measuring the amount of progestin remaining in contraceptive implants used for different lengths of time provides useful information on in vivo release kinetics including change over time. We compared estimated in vivo levonorgestrel (LNG) release rates derived from Sino-implant (II) explants with similar data from removed Jadelle. We measured LNG remaining in 44 sets of Sino-implant (II) used for up to 7 years and removed in four Chinese clinics. Results were compared with published data for Jadelle explants used for up to 36 months. We estimated and compared monthly and daily LNG release rates for the two products using prediction models for drug release. We also estimated the dissolution profile similarity factor, f2, for LNG release. Both Sino-implant (II) and Jadelle release approximately 30% of total LNG load after 3 years. Results of fitting the data to a biologically plausible modified Higuchi prediction model indicate comparable release through 3 years. An estimated similarity factor of 80.6 (90% confidence interval: 70.8-85.7) indicates similarity in the dissolution profiles of the two implants. LNG release in vivo measured through explant analysis suggest that Sino-implant (II) and Jadelle may perform similarly through 3 years of use and could remain highly effective beyond this time point. These results align with published data for Jadelle and Sino-implant (II) showing high effectiveness for 5 years. Ongoing clinical studies comparing the products over 5 years present an opportunity to verify this supportive measure of clinical effectiveness. This innovative approach provides evidence that Sino-implant (II) may perform clinically similarly to Jadelle over 3 years and remain a highly effective contraceptive beyond this time point. Data from explant analyses show promise for investigating the equivalence of elusion profiles of contraceptive implants. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Quantifying the flow rate of the Deepwater Horizon Macondo Well oil spill

NASA Astrophysics Data System (ADS)

Camilli, R.; Bowen, A.; Yoerger, D. R.; Whitcomb, L. L.; Techet, A. H.; Reddy, C. M.; Sylva, S.; Seewald, J.; di Iorio, D.; Whoi Flow Rate Measurement Group

2010-12-01

The Deepwater Horizon blowout in the Mississippi Canyon block 252 of the Gulf of Mexico created the largest recorded offshore oil spill. The well outflow’s multiple leak sources, turbulent multiphase flow, tendency for hydrate formation, and extreme source depth of 1500 m below the sea surface complicated the quantitative estimation of oil and gas leakage rates. We present methods and results from a U.S. Coast Guard sponsored flow assessment study of the Deepwater Horizon’s damaged blow out preventer and riser. This study utilized a remotely operated vehicle equipped with in-situ acoustic sensors (a Doppler sonar and an imaging multibeam sonar) and isobaric gas-tight fluid samplers to measure directly outflow from the damaged well. Findings from this study indicate oil release rates and total release volume estimates that corroborate estimates made by the federal government’s Flow Rate Technical Group using non-acoustic techniques. The acoustic survey methods reported here provides a means for estimating fluid flow rates in subsurface environments, and are potentially useful for a diverse range of oceanographic applications. Photograph of the Discoverer Enterprise burning natural gas collected from the Macondo well blowout preventer during flow measurement operations. Copyright Wood Hole Oceanographic Institution.

Recharge of the early atmosphere of Mars by impact-induced release of CO2

NASA Technical Reports Server (NTRS)

Carr, Michael H.

1989-01-01

The question as to whether high impact rates early in the history of Mars could have aided in maintaining a relatively thick CO2 atmosphere is discussed. Such impacts could have released CO2 into the atmosphere by burial, by shock-induced release during impact events, and by the addition of carbon to Mars from the impacting bolides. On the assumption that cratering rates on Mars were comparable to those of the moon's Nectarial period, burial rates are a result of 'impact gardening' at the end of heavy bombardment are estimated to have ranged from 20 to 45 m/million years; at these rates, 0.1-0.2 bar of CO2 would have been released every 10 million years as a result of burial to depths at which carbonate dissociation temperatures are encountered.

Radioactive release during nuclear accidents in Chernobyl and Fukushima

NASA Astrophysics Data System (ADS)

Nur Ain Sulaiman, Siti; Mohamed, Faizal; Rahim, Ahmad Nabil Ab

2018-01-01

Nuclear accidents that occurred in Chernobyl and Fukushima have initiated many research interests to understand the cause and mechanism of radioactive release within reactor compound and to the environment. Common types of radionuclide release are the fission products from the irradiated fuel rod itself. In case of nuclear accident, the focus of monitoring will be mostly on the release of noble gases, I-131 and Cs-137. As these are the only accidents have been rated within International Nuclear Events Scale (INES) Level 7, the radioactive release to the environment was one of the critical insights to be monitored. It was estimated that the release of radioactive material to the atmosphere due to Fukushima accident was approximately 10% of the Chernobyl accident. By referring to the previous reports using computational code systems to model the release rate, the release activity of I-131 and Cs-137 in Chernobyl was significantly higher compare to Fukushima. The simulation code also showed that Chernobyl had higher release rate of both radionuclides on the day of accident. Other factors affecting the radioactive release for Fukushima and Chernobyl accidents such as the current reactor technology and safety measures are also compared for discussion.

Abundance of adult horseshoe crabs (Limulus polylphemus) in Delaware Bay estimated from a bay-wide mark-recapture study

USGS Publications Warehouse

Smith, D.R.; Millard, M.J.; Eyler, S.

2006-01-01

Estimates of the abundance of American horseshoe crabs (Limulus polyphemus) are important to determine egg production and to manage populations for the energetic needs of shorebirds that feed on horseshoe crab eggs. In 2003, over 17,500 horseshoe crabs were tagged and released throughout Delaware Bay, and recaptured crabs came from spawning surveys that were conducted during peak spawning. We used two release cohorts to test for a temporary effect of tagging on spawning behavior and we adjusted the number of releases according to relocation rates from a telemetry study. The abundance estimate was 20 million horseshoe crabs (90% confidence interval: 13-28 million), of which 6.25 million (90% CI: 4.0-8.8 million) were females. The combined harvest rate for Delaware, New Jersey, Virginia, and Maryland in 2003 was 4% (90% CI: 3-6%) of the abundance estimate. Over-wintering of adults in Delaware Bay could explain, in part, differences in estimates from ocean-trawl surveys. Based on fecundity of 88,000 eggs per female, egg production was 5.5??1011 (90% CI: 3.5??1011, 7.7??1011), but egg availability for shorebirds also depended on overlap between horseshoe crab and shorebird migrations, density-dependent bioturbation, and wave-mediated vertical transport.

Assimilation of concentration measurements for retrieving multiple point releases in atmosphere: A least-squares approach to inverse modelling

NASA Astrophysics Data System (ADS)

Singh, Sarvesh Kumar; Rani, Raj

2015-10-01

The study addresses the identification of multiple point sources, emitting the same tracer, from their limited set of merged concentration measurements. The identification, here, refers to the estimation of locations and strengths of a known number of simultaneous point releases. The source-receptor relationship is described in the framework of adjoint modelling by using an analytical Gaussian dispersion model. A least-squares minimization framework, free from an initialization of the release parameters (locations and strengths), is presented to estimate the release parameters. This utilizes the distributed source information observable from the given monitoring design and number of measurements. The technique leads to an exact retrieval of the true release parameters when measurements are noise free and exactly described by the dispersion model. The inversion algorithm is evaluated using the real data from multiple (two, three and four) releases conducted during Fusion Field Trials in September 2007 at Dugway Proving Ground, Utah. The release locations are retrieved, on average, within 25-45 m of the true sources with the distance from retrieved to true source ranging from 0 to 130 m. The release strengths are also estimated within a factor of three to the true release rates. The average deviations in retrieval of source locations are observed relatively large in two release trials in comparison to three and four release trials.

Tryptophan availability modulates serotonin release from rat hypothalamic slices

NASA Technical Reports Server (NTRS)

Schaechter, Judith D.; Wurtman, Richard J.

1989-01-01

The relationship between the tryptophan availability and serononin release from rat hypothalamus was investigated using a new in vitro technique for estimating rates at which endogenous serotonin is released spontaneously or upon electrical depolarization from hypothalamic slices superfused with a solution containing various amounts of tryptophan. It was found that the spontaneous, as well as electrically induced, release of serotonin from the brain slices exhibited a dose-dependent relationship with the tryptophan concentration of the superfusion medium.

Models to describe the thermal development rates of Cycloneda sanguinea L. (Coleoptera: Coccinelidae).

PubMed

Pachú, Jéssica Ks; Malaquias, José B; Godoy, Wesley Ac; de S Ramalho, Francisco; Almeida, Bruna R; Rossi, Fabrício

2018-04-01

Precise estimates of the lower (T min ) and higher (T max ) thermal thresholds as well as the temperature range that provides optimum performance (T opt ) enable to obtain the desired number of individuals in conservation systems, rearing and release of natural enemies. In this study, the relationship between the development rates of Cycloneda sanguinea L. (Coleoptera: Coccinelidae) and temperature was described using non-linear models developed by Analytis, Brière, Lactin, Lamb, Logan and Sharpe & DeMichele. There were differences between the models, considering the estimates of the parameters T min , T max , and T opt . All of the tested models were able to describe non-linear responses involving the development rates of C. sanguinea at constant temperatures. Lactin and Lamb gave the highest z weight for egg, while Analytis, Sharpe & DeMichele and Brière gave the highest values for larvae and pupae. The more realistic T opt estimated by the models varied from 29° to 31°C for egg, 27-28 °C for larvae and 28-29 °C for pupae. The Logan, Lactin and Analytis models estimated the T max for egg, larvae and pupae to be approximately 34 °C, while the T min estimated by the Analytis model was 16 °C for larvae and pupae. The information generated by our research will contribute towards improving the rearing and release of C. sanguinea in biological control programs, accurately controlling the rate of development in laboratory conditions or even scheduling the most favourable this species' release. Copyright © 2018 Elsevier Ltd. All rights reserved.

Measuring the Acoustic Release of a Chemotherapeutic Agent from Folate-Targeted Polymeric Micelles.

PubMed

Abusara, Ayah; Abdel-Hafez, Mamoun; Husseini, Ghaleb

2018-08-01

In this paper, we compare the use of Bayesian filters for the estimation of release and re-encapsulation rates of a chemotherapeutic agent (namely Doxorubicin) from nanocarriers in an acoustically activated drug release system. The study is implemented using an advanced kinetic model that takes into account cavitation events causing the antineoplastic agent's release from polymeric micelles upon exposure to ultrasound. This model is an improvement over the previous representations of acoustic release that used simple zero-, first- and second-order release and re-encapsulation kinetics to study acoustically triggered drug release from polymeric micelles. The new model incorporates drug release and micellar reassembly events caused by cavitation allowing for the controlled release of chemotherapeutics specially and temporally. Different Bayesian estimators are tested for this purpose including Kalman filters (KF), Extended Kalman filters (EKF), Particle filters (PF), and multi-model KF and EKF. Simulated and experimental results are used to verify the performance of the above-mentioned estimators. The proposed methods demonstrate the utility and high-accuracy of using estimation methods in modeling this drug delivery technique. The results show that, in both cases (linear and non-linear dynamics), the modeling errors are expensive but can be minimized using a multi-model approach. In addition, particle filters are more flexible filters that perform reasonably well compared to the other two filters. The study improved the accuracy of the kinetic models used to capture acoustically activated drug release from polymeric micelles, which may in turn help in designing hardware and software capable of precisely controlling the delivered amount of chemotherapeutics to cancerous tissue.

Reduction of calcium inactivation of sarcoplasmic reticulum calcium release by fura-2 in voltage-clamped cut twitch fibers from frog muscle

PubMed Central

1993-01-01

Cut fibers from Rana temporaria and Rana pipiens (striation spacing, 3.9-4.2 microns) were mounted in a double Vaseline-gap chamber and studied at 14 degrees C. The Ca indicator purpurate-3,3' diacetic acid (PDAA) was introduced into the end pools and allowed to diffuse into the optical recording site. When the concentration at the site exceeded 2 mM, step depolarizations to 10 mV were applied and the [Ca] transient measured with PDAA was used to estimate Ca release from the sarcoplasmic reticulum (SR) (Baylor, S. M., W. K. Chandler, and M. W. Marshall. 1983. Journal of Physiology. 344:625-666). With depolarization, the rate of SR Ca release increased to an early peak and then rapidly decreased several-fold to a quasi-steady level. The total amount of Ca released from the SR at the time of peak rate of release appeared to be independent of SR Ca content, consistent with the idea that a single activated channel might pass, on average, a fixed number of ions, independent of the magnitude of the single channel flux. A possible explanation of this property is given in terms of locally induced Ca inactivation of Ca release. The solution in the end pools was then changed to one with PDAA plus fura-2. SR Ca release was estimated from the [Ca] transient, as before, and from the delta [Cafura-2] signal. On average, 2-3 mM fura-2 increased the quasi-steady level of the rate of SR Ca release by factors of 6.6 and 3.8, respectively, in three fibers from Rana temporaria and three fibers from Rana pipiens. The peak rate of release was increased in five of the six fibers but to a lesser extent than the quasi-steady level. In all fibers, the amplitude of the free [Ca] transient was markedly reduced. These increases in the rate of SR Ca release are consistent with the idea that Ca inactivation of Ca release develops during a step depolarization to 10 mV and that 2-3 mM fura-2 is able to reduce this inactivation by complexing Ca and thereby reducing free [Ca]. Once the concentration of fura-2 becomes sufficiently large, a further increase reduces the rate of SR Ca release. On average, 5-6 mM fura-2 increased the quasi-steady rate of release, compared with 0 mM fura-2, by 6.5 and 2.9, respectively, in four fibers from Rana temporaria and three from Rana pipiens.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8228914

Mixing Efficiency in the Ocean.

PubMed

Gregg, M C; D'Asaro, E A; Riley, J J; Kunze, E

2018-01-03

Mixing efficiency is the ratio of the net change in potential energy to the energy expended in producing the mixing. Parameterizations of efficiency and of related mixing coefficients are needed to estimate diapycnal diffusivity from measurements of the turbulent dissipation rate. Comparing diffusivities from microstructure profiling with those inferred from the thickening rate of four simultaneous tracer releases has verified, within observational accuracy, 0.2 as the mixing coefficient over a 30-fold range of diapycnal diffusivities. Although some mixing coefficients can be estimated from pycnocline measurements, at present mixing efficiency must be obtained from channel flows, laboratory experiments, and numerical simulations. Reviewing the different approaches demonstrates that estimates and parameterizations for mixing efficiency and coefficients are not converging beyond the at-sea comparisons with tracer releases, leading to recommendations for a community approach to address this important issue.

Mixing Efficiency in the Ocean

NASA Astrophysics Data System (ADS)

Gregg, M. C.; D'Asaro, E. A.; Riley, J. J.; Kunze, E.

2018-01-01

Mixing efficiency is the ratio of the net change in potential energy to the energy expended in producing the mixing. Parameterizations of efficiency and of related mixing coefficients are needed to estimate diapycnal diffusivity from measurements of the turbulent dissipation rate. Comparing diffusivities from microstructure profiling with those inferred from the thickening rate of four simultaneous tracer releases has verified, within observational accuracy, 0.2 as the mixing coefficient over a 30-fold range of diapycnal diffusivities. Although some mixing coefficients can be estimated from pycnocline measurements, at present mixing efficiency must be obtained from channel flows, laboratory experiments, and numerical simulations. Reviewing the different approaches demonstrates that estimates and parameterizations for mixing efficiency and coefficients are not converging beyond the at-sea comparisons with tracer releases, leading to recommendations for a community approach to address this important issue.

Strain Rate Dependency of Fracture Toughness, Energy Release Rate and Geomechanical Attributes of Select Indian Shales

NASA Astrophysics Data System (ADS)

Mahanta, B.; Vishal, V.; Singh, T. N.; Ranjith, P.

2016-12-01

In addition to modern improved technology, it requires detailed understanding of rock fractures for the purpose of enhanced energy extraction through hydraulic fracturing of gas shales and geothermal energy systems. The understanding of rock fracture behavior, patterns and properties such as fracture toughness; energy release rate; strength and deformation attributes during fracturing hold significance. Environmental factors like temperature, pressure, humidity, water vapor and experimental condition such as strain rate influence the estimation of these properties. In this study, the effects of strain rates on fracture toughness, energy release rate as well as geomechanical properties like uniaxial compressive strength, Young's modulus, failure strain, tensile strength, and brittleness index of gas shales were investigated. In addition to the rock-mechanical parameters, the fracture toughness and the energy release rates were measured for three different modes viz. mode I, mixed mode (I-II) and mode II. Petrographic and X-ray diffraction (XRD) analyses were performed to identify the mineral composition of the shale samples. Scanning electron microscope (SEM) analyses were conducted to have an insight about the strain rate effects on micro-structure of the rock. The results suggest that the fracture toughness; the energy release rate as well as other geomechanical properties are a function of strain rates. At high strain rates, the strength and stiffness of shale increases which in turn increases the fracture toughness and the energy release rate of shale that may be due to stress redistribution during grain fracturing. The fracture toughness and the strain energy release rates for all the modes (I/I-II/II) are comparable at lower strain rates, but they vary considerably at higher strain rates. In all the cases, mode I and mode II fracturing requires minimum and maximum applied energy, respectively. Mode I energy release rate is maximum, compared to the other modes.

Snake River Sockeye Salmon Captive Broodstock Program; Research Element, 2003 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willard, Catherine; Plaster, Kurtis; Castillo, Jason

2005-01-01

On November 20, 1991, the National Oceanic Atmospheric Administration listed Snake River sockeye salmon Oncorhynchus nerka as endangered under the Endangered Species Act of 1973. In 1991, the Shoshone-Bannock Tribes (SBT) and Idaho Department of Fish and Game (IDFG) initiated the Snake River Sockeye Salmon Captive Broodstock Program to conserve and rebuild populations in Idaho. Restoration efforts are focused on Redfish, Pettit, and Alturas lakes within the Sawtooth Valley. The first release of hatchery-produced adults occurred in 1993. The first release of juvenile sockeye salmon from the captive broodstock program occurred in 1994. In 1999, the first anadromous adult returnsmore » from the captive broodstock program were recorded when six jacks and one jill were captured at the IDFG Sawtooth Fish Hatchery. In 2003, progeny from the captive broodstock program were released using three strategies: eyed-eggs were planted in Pettit and Alturas lakes in November and December, age-0 presmolts were released to Alturas, Pettit, and Redfish lakes in October, and hatchery-produced adult sockeye salmon were released to Redfish Lake for volitional spawning in September. Oncorhynchus nerka population monitoring was conducted on Redfish, Alturas, and Pettit lakes using a midwater trawl in September 2003. Age-0 through age-4 O. nerka were captured in Redfish Lake, and population abundance was estimated at 81,727 fish. Age-0 through age-3 O. nerka were captured in Alturas Lake, and population abundance was estimated at 46,234 fish. Age-0 through age-3 O. nerka were captured in Pettit Lake, and population abundance was estimated at 11,961 fish. Angler surveys were conducted from May 25 through August 7, 2003 on Redfish Lake to estimate kokanee harvest. On Redfish Lake, we interviewed 179 anglers and estimated that 424 kokanee were harvested. The calculated kokanee catch rate was 0.09 fish/hour. The juvenile out-migrant trap on Redfish Lake Creek was operated from April 15 to May 29, 2003. We estimated that 4,637 wild/natural and 12,226 hatchery-produced sockeye salmon smolts out-migrated from Redfish Lake in 2003. The hatchery-produced component included an estimated 5,352 out-migrants produced from a summer direct-release made to Redfish Lake in 2002 and 6,874 out-migrants produced from a fall direct-release made in 2002. The juvenile out-migrant traps on Alturas Lake Creek and Pettit Lake Creek were operated by the SBT from April 23 to June 5, 2003 and April 25 to June 4, 2003, respectively. The SBT enumerated 28 wild/natural and 13,329 hatchery-produced sockeye salmon smolts that outmigrated from Pettit Lake and estimated 286 wild/natural and 553 hatchery-produced sockeye salmon smolts out-migrated from Alturas Lake in 2003. The hatchery-produced component of sockeye salmon out-migrants originated from presmolt releases made directly to Pettit and Alturas lakes in 2002. Median travel times for passive integrated transponder (PIT) tagged smolts from the Redfish Lake Creek trap site to Lower Granite Dam were estimated for wild/natural smolts and hatchery-produced smolts. Median travel times for smolts originating from the Redfish Lake Creek trap were 10.6 d for wild/natural smolts, 6.2 d for summer direct-released smolts, and 7.1 d for fall direct-released smolts. Median travel times for PIT-tagged smolts from the Pettit Lake Creek trap site to Lower Granite Dam were estimated for hatchery-produced smolts. Median travel times for smolts originating from the Pettit Lake Creek trap were 14.1 d for fall direct released smolts and 13.6 d for fall direct released smolts. Cumulative unique PIT tag interrogations from Sawtooth Valley juvenile out-migrant traps to mainstem Snake and Columbia river dams were utilized to estimate detection rates for out-migrating sockeye salmon smolts. Detection rate comparisons were made between smolts originating from Redfish, Alturas, and Pettit lakes and the various release strategies. Pettit Lake fall direct released smolts recorded the highest detection rate of 37.14%. In 2003, 312 hatchery-produced adult sockeye salmon were released to Redfish Lake for natural spawning. We observed 42 areas of excavation in the lake from spawning events. Suspected redds were approximately 3 m x 3 m in size and were constructed by multiple pairs of adults. We monitored bull trout spawning in Fishhook Creek, a tributary to Redfish Lake, and in Alpine Creek, a tributary to Alturas Lake. This represented the sixth consecutive year that the index reaches have been surveyed on these two streams. Adult counts (40 adults) and redd counts (17 redds) in Fishhook Creek were similar to counts conducted since monitoring began in 1998. Bull trout numbers (27 adults) and the number of redds observed (14 redds) have gradually increased in Alpine Creek compared to counts from initial monitoring.« less

Determination of water use in Rockford and Kankakee areas, Illinois

USGS Publications Warehouse

LaTour, John K.

1991-01-01

Amounts of water withdrawn, delivered, consumed, released, returned, and lost or gained during conveyance were determined for six communities--Rockford, Loves Park, North Park, Kankakee, Bourbonnais, and Bradley--served by the public-water systems in the Rockford and the Kankakee areas of Illinois. Water-use categories studied were commercial, industrial, domestic, and municipal uses; public supply; and sewage treatment. The availability and accuracy of water-use data are described, and water-use coefficients and methods of estimating water use are provided to improve the collection and the analysis of water-use information. Water-use data were obtained from all the water utilities and from 30 major water users in the Rockford and the Kankakee areas. Data were available for water withdrawals by water suppliers; deliveries by water suppliers to water users; returns by sewage-treatment plants and water users; releases by water users to sewers; and sewer-conveyance losses. Accuracy of the water-use data was determined from discharge measurements or reliability tests of water meters, or was estimated according to the completeness of the data. Accuracy of withdrawal and sewage-treatment-return data for the Rockford area and of withdrawal, delivery, industrial release, and sewage-treatment-return data for the Kankakee area was considered to be at least 90 percent. Where water-use data were inadequate or unavailable, various methods were used to estimate consumptive uses; releases; returns by commercial, domestic, and municipal users; and conveyance losses and gains. The methods focused on water budgeting to assure that water uses balanced. Consumptive uses were estimated by use of the consumption-budget method, the types-of-use method, consumptive-use ratios, the winter base-rate method, and the maximum lawn-watering method. The winter base-rate method provided the best domestic consumptive-use estimates, whose ratios (consumptive use from the winter base-rate method divided by deliveries and self-supply withdrawals), by community, ranged from 0.03 to 0.136 and averaged 0.068. The consumption-budget and types-of-use methods, as well as consumptive-use ratios, were used to estimate consumptive use for commercial, industrial, and municipal categories. Water budgeting was generally used to estimate releases, and conveyance losses and gains. Estimates of nonconsumptive uses by cooling systems, boilers, and lawn watering; data of deliveries to septic-system owners; and (or) water budgeting were used to estimate commercial, domestic, industrial, and municipal returns. Proportions of water use were similar in the Rockford and the Kankakee areas. Of the public-supply withdrawals in each area, about one-half was delivered for commercial and industrial uses; about one-third for domestic use; and about one-sixth for municipal use and public-supply conveyance losses.Consumptive use by all water users in the Rockford and the Kankakee areas was 13 +/- 1 percent, releases were 78 +/- 2 percent, and returns were 9 +/- 2 percent of deliveries and self-supply withdrawals. Total returns were greater than total withdrawals in the two areas because-of sewer-conveyance gains, which amounted to about 34 percent of the sewage-treatment returns for each area. Delivery rates (deliveries divided by the number of users [establishments or households]) and domestic per capita use were similar for all six communities. At a 95-percent confidence level, domestic delivery rates for each community range from 0.067 to 0.075 million gallons per household per year. Commercial delivery rates range from 0.277 to 0.535 million gallons per establishment per year. Delivery rates for all categories combined range from 0.100 to 0.192 million gallons per user per year. Domestic per capita use, which ranged from 67.2 to 71.0 gallons per day, averaged 69.2 +/- 1.1 gallons per day.

Statistical atmospheric inversion of local gas emissions by coupling the tracer release technique and local-scale transport modelling: a test case with controlled methane emissions

NASA Astrophysics Data System (ADS)

Ars, Sébastien; Broquet, Grégoire; Yver Kwok, Camille; Roustan, Yelva; Wu, Lin; Arzoumanian, Emmanuel; Bousquet, Philippe

2017-12-01

This study presents a new concept for estimating the pollutant emission rates of a site and its main facilities using a series of atmospheric measurements across the pollutant plumes. This concept combines the tracer release method, local-scale atmospheric transport modelling and a statistical atmospheric inversion approach. The conversion between the controlled emission and the measured atmospheric concentrations of the released tracer across the plume places valuable constraints on the atmospheric transport. This is used to optimise the configuration of the transport model parameters and the model uncertainty statistics in the inversion system. The emission rates of all sources are then inverted to optimise the match between the concentrations simulated with the transport model and the pollutants' measured atmospheric concentrations, accounting for the transport model uncertainty. In principle, by using atmospheric transport modelling, this concept does not strongly rely on the good colocation between the tracer and pollutant sources and can be used to monitor multiple sources within a single site, unlike the classical tracer release technique. The statistical inversion framework and the use of the tracer data for the configuration of the transport and inversion modelling systems should ensure that the transport modelling errors are correctly handled in the source estimation. The potential of this new concept is evaluated with a relatively simple practical implementation based on a Gaussian plume model and a series of inversions of controlled methane point sources using acetylene as a tracer gas. The experimental conditions are chosen so that they are suitable for the use of a Gaussian plume model to simulate the atmospheric transport. In these experiments, different configurations of methane and acetylene point source locations are tested to assess the efficiency of the method in comparison to the classic tracer release technique in coping with the distances between the different methane and acetylene sources. The results from these controlled experiments demonstrate that, when the targeted and tracer gases are not well collocated, this new approach provides a better estimate of the emission rates than the tracer release technique. As an example, the relative error between the estimated and actual emission rates is reduced from 32 % with the tracer release technique to 16 % with the combined approach in the case of a tracer located 60 m upwind of a single methane source. Further studies and more complex implementations with more advanced transport models and more advanced optimisations of their configuration will be required to generalise the applicability of the approach and strengthen its robustness.

Quantification of Kinetic Rate Law Parameters of Uranium Release from Sodium Autunite as a Function of Aqueous Bicarbonate Concentrations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.

2013-09-05

ABSTRACT: Hydrogen carbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, hydrogen carbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous hydrogen carbonate solutions to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate solutions (0.0005-0.003 M) under the pH range of 6-11 and temperaturesmore » of 5-60oC. Consistent with the results of previous investigation, the rate of uranium release from sodium autunite exhibited minimal dependency on temperature; but were strongly dependent on pH and increasing concentrations of bicarbonate solutions. Most notably at pH 7, the rate of uranium release exhibited 370 fold increases relative to the rate of uranium release in the absence of bicarbonate. However, the effect of increasing concentrations of bicarbonate solutions on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release. Results indicate the activation energies were unaffected by temperature and bicarbonate concentration variations, but were strongly dependent on pH conditions. As pH increased from 6 to 11, activation energy values were observed to decrease from 29.94 kJ mol-1 to 13.07 kJ mol-1. The calculated activation energies suggest a surface controlled dissolution mechanism.« less

Simulation and analysis of chemical release in the ionosphere

NASA Astrophysics Data System (ADS)

Gao, Jing-Fan; Guo, Li-Xin; Xu, Zheng-Wen; Zhao, Hai-Sheng; Feng, Jie

2018-05-01

Ionospheric inhomogeneous plasma produced by single point chemical release has simple space-time structure, and cannot impact radio wave frequencies higher than Very High Frequency (VHF) band. In order to produce more complicated ionospheric plasma perturbation structure and trigger instabilities phenomena, multiple-point chemical release scheme is presented in this paper. The effects of chemical release on low latitude ionospheric plasma are estimated by linear instability growth rate theory that high growth rate represents high irregularities, ionospheric scintillation occurrence probability and high scintillation intension in scintillation duration. The amplitude scintillations and the phase scintillations of 150 MHz, 400 MHz, and 1000 MHz are calculated based on the theory of multiple phase screen (MPS), when they propagate through the disturbed area.

Estimating methane gas production in peat soils of the Florida Everglades using hydrogeophysical methods

NASA Astrophysics Data System (ADS)

Wright, William; Comas, Xavier

2016-04-01

The spatial and temporal variability in production and release of greenhouse gases (such as methane) in peat soils remains uncertain, particularly for low-latitude peatlands like the Everglades. Ground penetrating radar (GPR) is a hydrogeophysical tool that has been successfully used in the last decade to noninvasively investigate carbon dynamics in peat soils; however, application in subtropical systems is almost non-existent. This study is based on four field sites in the Florida Everglades, where changes in gas content within the soil are monitored using time-lapse GPR measurements and gas releases are monitored using gas traps. A weekly methane gas production rate is estimated using a mass balance approach, considering gas content estimated from GPR, gas release from gas traps and incorporating rates of diffusion, and methanotrophic consumption from previous studies. Resulting production rates range between 0.02 and 0.47 g CH4 m-2 d-1, falling within the range reported in literature. This study shows the potential of combining GPR with gas traps to monitor gas dynamics in peat soils of the Everglades and estimate methane gas production. We also show the enhanced ability of certain peat soils to store gas when compared to others, suggesting that physical properties control biogenic gas storage in the Everglades peat soils. Better understanding biogenic methane gas dynamics in peat soils has implications regarding the role of wetlands in the global carbon cycle, particularly under a climate change scenario.

Nanodust released in interplanetary collisions

NASA Astrophysics Data System (ADS)

Lai, H. R.; Russell, C. T.

2018-07-01

The lifecycle of near-Earth objects (NEOs) involves a collisional cascade that produces ever smaller debris ending with nanoscale particles which are removed from the solar system by radiation pressure and electromagnetic effects. It has been proposed that the nanodust clouds released in collisions perturb the background interplanetary magnetic field and create the interplanetary field enhancements (IFEs). Assuming that this IFE formation scenario is actually operating, we calculate the interplanetary collision rate, estimate the total debris mass carried by nanodust, and compare the collision rate with the IFE rate. We find that to release the same amount of nanodust, the collision rate is comparable to the observed IFE rate. Besides quantitatively testing the association between the collisions evolving large objects and giant solar wind structures, such a study can be extended to ranges of smaller scales and to investigate the source of moderate and small solar wind perturbations.

An extended model of vesicle fusion at the plasma membrane to estimate protein lateral diffusion from TIRF microscopy images.

PubMed

Basset, Antoine; Bouthemy, Patrick; Boulanger, Jérôme; Waharte, François; Salamero, Jean; Kervrann, Charles

2017-07-24

Characterizing membrane dynamics is a key issue to understand cell exchanges with the extra-cellular medium. Total internal reflection fluorescence microscopy (TIRFM) is well suited to focus on the late steps of exocytosis at the plasma membrane. However, it is still a challenging task to quantify (lateral) diffusion and estimate local dynamics of proteins. A new model was introduced to represent the behavior of cargo transmembrane proteins during the vesicle fusion to the plasma membrane at the end of the exocytosis process. Two biophysical parameters, the diffusion coefficient and the release rate parameter, are automatically estimated from TIRFM image sequences, to account for both the lateral diffusion of molecules at the membrane and the continuous release of the proteins from the vesicle to the plasma membrane. Quantitative evaluation on 300 realistic computer-generated image sequences demonstrated the efficiency and accuracy of the method. The application of our method on 16 real TIRFM image sequences additionally revealed differences in the dynamic behavior of Transferrin Receptor (TfR) and Langerin proteins. An automated method has been designed to simultaneously estimate the diffusion coefficient and the release rate for each individual vesicle fusion event at the plasma membrane in TIRFM image sequences. It can be exploited for further deciphering cell membrane dynamics.

Migration protocol to estimate metal exposure from mouthing copper and tin alloy objects

PubMed Central

2014-01-01

Background Low blood lead levels previously thought to pose no health risks may have an adverse impact on the cognitive development of children. This concern has given rise to new regulatory restrictions upon lead metal containing products intended for child use. However few reliable experimental testing methods to estimate exposure levels from these materials are available. Methods The present work describes a migration test using a mimetic saliva fluid to estimate the chronic exposure of children to metals such as lead while mouthing metallic objects. The surrogate saliva medium was composed of: 150 mM NaCl, 0.16% porcine Mucin and 5 mM buffer MOPS, adjusted to pH 7.2. Alloys samples, in the form of polished metallic disc of known surface area, were subjected to an eight hours test. Results Two whitemetal alloys Sn/Pb/Sb/Cu and three brass alloys Cu/Zn/Pb were tested using the saliva migration protocol. In the case of the whitemetal alloys, first order release kinetics resulting in the release of 0.03 and 0.51 μg lead/cm2 after 8 hours of tests were observed, for lead contents of 0.05-0.07% and 5.5%, respectively. Brasses exhibited linear incremental release rates of 0.043, 0.175 and 0.243 μg lead/cm2h for lead contents of 0.1-0.2%, 1.7-2.2% and 3.1-3.5%, respectively. The linear regression analysis of lead release rates relative to Pb content in brasses yielded a slope of 0.08 μg lead/cm2h%Pb (r2 = 0.92). Lead release rates were used to estimate the mean daily mouthing exposure of a child to lead, according to age-specific estimates of mouthing time behavior. Calculated daily intakes were used as oral inputs for the IEUBK toxicokinetic model, predicting only marginal changes in blood lead levels (0.2 μg lead/dL or less) for children aged 0.5 to 1 years old exposed to either class of alloy. Conclusions The results of this study as a whole support the use of migration data of metal ions, rather than total metal content, to estimate health risk from exposure to metals and metal alloys substances in children. PMID:25113236

Research, monitoring, and evaluation of emerging issues and measures to recover the Snake River Fall Chinook Salmon ESU, 1/1/2016 - 12/31/2016

USGS Publications Warehouse

Connor, William P.; Mullins, Frank L.; Tiffan, Kenneth F.; Plumb, John M.; Perry, Russell W.; Erhardt, John M.; Hemingway, Rulon J.; Bickford, Brad; Rhodes, Tobyn N.

2017-01-01

The portion of the Snake River fall Chinook Salmon Oncorhynchus tshawytscha ESU that spawns upstream of Lower Granite Dam transitioned from low to high abundance during 1992–2016 in association with U.S. Endangered Species Act recovery efforts and other federally mandated actions. This annual report focuses on (1) numeric and habitat use responses by natural- and hatchery-origin spawners, (2) phenotypic and numeric responses by natural-origin juveniles, and (3) predator responses in the Snake River upper and lower reaches as abundance of adult and juvenile fall Chinook Salmon increased. Spawners have located and used most of the available spawning habitat and that habitat is gradually approaching redd capacity. Timing of spawning and fry emergence has been relatively stable; whereas the timing of parr dispersal from riverine rearing habitat into Lower Granite Reservoir has become earlier as apparent abundance of juveniles has increased. Growth rate (g/d) and dispersal size of parr also declined as apparent abundance of juveniles increased. Passage timing of smolts from the two Snake River reaches has become earlier and downstream movement rate faster as estimated abundance of fall Chinook Salmon smolts in Lower Granite Reservoir has increased. In 2016, we described estimated the consumption rate and loss of subyearlings by Smallmouth Bass before, during, and after four hatchery releases. Before releases, Smallmouth Bass consumption rates of subyearling was low (0–0.36 fish/bass/d), but the day after the releases consumption rates reached as high as 1.6 fish/bass/d. Bass consumption in the upper portion of Hells Canyon was high for about 1–2 d before returning to pre-release levels, but in the lower river consumption rates were reduced but took longer to return to pre-release levels. We estimated that most of the subyearlings consumed by bass were of hatchery origin. Smallmouth Bass predation on subyearlings is intense following a hatchery release, but the predation pressure is relatively short-lived as subyearlings quickly disperse downstream. This information will allow us to better estimate subyearling loss to predation from our past efforts at time intervals less than 2 weeks. These findings coupled with stock-recruitment analyses presented in this report provide evidence for density-dependence in the Snake River reaches and in Lower Granite Reservoir that was influenced by the expansion of the recovery program. The long-term goal is to use the information covered here in a comprehensive modeling effort to conduct action effectiveness and uncertainty research and to inform Fish Population, Hydrosystem, Harvest, Hatchery, and Predation and Invasive Species Management RM&E.

Effect of blood flow on near-the-wall mass transport of drugs and other bioactive agents: a simple formula to estimate boundary layer concentrations.

PubMed

Rugonyi, Sandra

2008-04-01

Transport of bioactive agents through the blood is essential for cardiovascular regulatory processes and drug delivery. Bioactive agents and other solutes infused into the blood through the wall of a blood vessel or released into the blood from an area in the vessel wall spread downstream of the infusion/release region and form a thin boundary layer in which solute concentration is higher than in the rest of the blood. Bioactive agents distributed along the vessel wall affect endothelial cells and regulate biological processes, such as thrombus formation, atherogenesis, and vascular remodeling. To calculate the concentration of solutes in the boundary layer, researchers have generally used numerical simulations. However, to investigate the effect of blood flow, infusion rate, and vessel geometry on the concentration of different solutes, many simulations are needed, leading to a time-consuming effort. In this paper, a relatively simple formula to quantify concentrations in a tube downstream of an infusion/release region is presented. Given known blood-flow rates, tube radius, solute diffusivity, and the length of the infusion region, this formula can be used to quickly estimate solute concentrations when infusion rates are known or to estimate infusion rates when solute concentrations at a point downstream of the infusion region are known. The developed formula is based on boundary layer theory and physical principles. The formula is an approximate solution of the advection-diffusion equations in the boundary layer region when solute concentration is small (dilute solution), infusion rate is modeled as a mass flux, and there is no transport of solute through the wall or chemical reactions downstream of the infusion region. Wall concentrations calculated using the formula developed in this paper were compared to the results from finite element models. Agreement between the results was within 10%. The developed formula could be used in experimental procedures to evaluate drug efficacy, in the design of drug-eluting stents, and to calculate rates of release of bioactive substances at active surfaces using downstream concentration measurements. In addition to being simple and fast to use, the formula gives accurate quantifications of concentrations and infusion rates under steady-state and oscillatory flow conditions, and therefore can be used to estimate boundary layer concentrations under physiological conditions.

Recharge of the early atmosphere of Mars by impact-induced release of CO2

USGS Publications Warehouse

Carr, Michael H.

1989-01-01

Channels on the Martian surface suggest that Mars had an early, relatively thick atmosphere. If the atmosphere was thick enough for water to be stable at the surface, CO2 in the atmosphere would have been fixed as carbonates on a relatively short time scale, previously estimated to be 1 bar every 107 years. This loss must have been offset by some replenishment mechanism to account for the numerous valley networks in the oldest surviving terrains. Impacts could have released CO2 into the atmosphere by burial, by shock-induced release during impact events, and by addition of carbon to Mars from the impacting bolides. Depending on the relationship between the transient cavity diameter and the diameter of the resulting crater, burial rates as a result of impact gardening at the end of heavy bombardment are estimated to range from 20 to 45 m/106 years, on the assumption that cratering rates in Mars were similar to those of the Nectarian Period on the Moon. At these rates 0.1-0.2 bar of CO2 could have been released every 107 years as a result of burial to depths where dissociation temperatures of carbonates were reached. Modeling of large impacts suggests that an additional 0.01 to 0.02 bar of CO2 could have been released every 107 years during the actual impacts. In the unlikely event that all the impacting material was composed of carbonaceous chondrites, a further 0.3 bar of CO2 could have been added to the atmosphere every 107 years by oxidation of meteoritic carbon. Even when supplemented by the volcanically induced release of CO2, these release rates are barely sufficient to sustain an early atmosphere if water were continuously present at the surface. The results suggest that water may have been only intermittently present on the surface early in the planet's history.

Decomposition and nutrient release from fresh and dried pine roots under two fertilizer regimes

Treesearch

Kim H. Ludovici; Lance W. Kress

2006-01-01

Root decomposition and nutrient release are typically estimated from dried root tissues; however, it is unlikely that roots dehydrate prior to decomposing. Soil fertility and root diameter may also affect the rate of decomposition. This study monitored mass loss and nutrient concentrations of dried and fresh roots of two size classes (

Quantification of methane fluxes from industrial sites using a combination of a tracer release method and a Gaussian model

NASA Astrophysics Data System (ADS)

Ars, S.; Broquet, G.; Yver-Kwok, C.; Wu, L.; Bousquet, P.; Roustan, Y.

2015-12-01

Greenhouse gas (GHG) concentrations keep on increasing in the atmosphere since industrial revolution. Methane (CH4) is the second most important anthropogenic GHG after carbon dioxide (CO2). Its sources and sinks are nowadays well identified however their relative contributions remain uncertain. The industries and the waste treatment emit an important part of the anthropogenic methane that is difficult to quantify because the sources are fugitive and discontinuous. A better estimation of methane emissions could help industries to adapt their mitigation's politic and encourage them to install methane recovery systems in order to reduce their emissions while saving money. Different methods exist to quantify methane emissions. Among them is the tracer release method consisting in releasing a tracer gas near the methane source at a well-known rate and measuring both their concentrations in the emission plume. The methane rate is calculated using the ratio of methane and tracer concentrations and the emission rate of the tracer. A good estimation of the methane emissions requires a good differentiation between the methane actually emitted by the site and the methane from the background concentration level, but also a good knowledge of the sources distribution over the site. For this purpose, a Gaussian plume model is used in addition to the tracer release method to assess the emission rates calculated. In a first step, the data obtained for the tracer during a field campaign are used to tune the model. Different model's parameterizations have been tested to find the best representation of the atmospheric dispersion conditions. Once these parameters are set, methane emissions are estimated thanks to the methane concentrations measured and a Bayesian inversion. This enables to adjust the position and the emission rate of the different methane sources of the site and remove the methane background concentration.

A GIS approach to conducting biogeochemical research in wetlands

NASA Technical Reports Server (NTRS)

Brannon, David P.; Irish, Gary J.

1985-01-01

A project was initiated to develop an environmental data base to address spatial aspects of both biogeochemical cycling and resource management in wetlands. Specific goals are to make regional methane flux estimates and site specific water level predictions based on man controlled water releases within a wetland study area. The project will contribute to the understanding of the Earth's biosphere through its examination of the spatial variability of methane emissions. Although wetlands are thought to be one of the primary sources for release of methane to the atmosphere, little is known about the spatial variability of methane flux. Only through a spatial analysis of methane flux rates and the environmental factors which influence such rates can reliable regional and global methane emissions be calculated. Data will be correlated and studied from Landsat 4 instruments, from a ground survey of water level recorders, precipitation recorders, evaporation pans, and supplemental gauges, and from flood gate water release; and regional methane flux estimates will be made.

Quantitative estimation of Nipah virus replication kinetics in vitro

PubMed Central

Chang, Li-Yen; Ali, AR Mohd; Hassan, Sharifah Syed; AbuBakar, Sazaly

2006-01-01

Background Nipah virus is a zoonotic virus isolated from an outbreak in Malaysia in 1998. The virus causes infections in humans, pigs, and several other domestic animals. It has also been isolated from fruit bats. The pathogenesis of Nipah virus infection is still not well described. In the present study, Nipah virus replication kinetics were estimated from infection of African green monkey kidney cells (Vero) using the one-step SYBR® Green I-based quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) assay. Results The qRT-PCR had a dynamic range of at least seven orders of magnitude and can detect Nipah virus from as low as one PFU/μL. Following initiation of infection, it was estimated that Nipah virus RNA doubles at every ~40 minutes and attained peak intracellular virus RNA level of ~8.4 log PFU/μL at about 32 hours post-infection (PI). Significant extracellular Nipah virus RNA release occurred only after 8 hours PI and the level peaked at ~7.9 log PFU/μL at 64 hours PI. The estimated rate of Nipah virus RNA released into the cell culture medium was ~0.07 log PFU/μL per hour and less than 10% of the released Nipah virus RNA was infectious. Conclusion The SYBR® Green I-based qRT-PCR assay enabled quantitative assessment of Nipah virus RNA synthesis in Vero cells. A low rate of Nipah virus extracellular RNA release and low infectious virus yield together with extensive syncytial formation during the infection support a cell-to-cell spread mechanism for Nipah virus infection. PMID:16784519

Analysis of dam-passage survival of yearling and subyearling Chinook salmon and juvenile steelhead at The Dalles Dam, Oregon, 2010

USGS Publications Warehouse

Beeman, John W.; Kock, Tobias J.; Perry, Russell W.; Smith, Steven G.

2011-01-01

We performed a series of analyses of mark-recapture data from a study at The Dalles Dam during 2010 to determine if model assumptions for estimation of juvenile salmonid dam-passage survival were met and if results were similar to those using the University of Washington's newly developed ATLAS software. The study was conducted by the Pacific Northwest National Laboratory and used acoustic telemetry of yearling Chinook salmon, juvenile steelhead, and subyearling Chinook salmon released at three sites according to the new virtual/paired-release statistical model. This was the first field application of the new model, and the results were used to measure compliance with minimum survival standards set forth in a recent Biological Opinion. Our analyses indicated that most model assumptions were met. The fish groups mixed in time and space, and no euthanized tagged fish were detected. Estimates of reach-specific survival were similar in fish tagged by each of the six taggers during the spring, but not in the summer. Tagger effort was unevenly allocated temporally during tagging of subyearling Chinook salmon in the summer; the difference in survival estimates among taggers was more likely a result of a temporal trend in actual survival than of tagger effects. The reach-specific survival of fish released at the three sites was not equal in the reaches they had in common for juvenile steelhead or subyearling Chinook salmon, violating one model assumption. This violation did not affect the estimate of dam-passage survival, because data from the common reaches were not used in its calculation. Contrary to expectation, precision of survival estimates was not improved by using the most parsimonious model of recapture probabilities instead of the fully parameterized model. Adjusting survival estimates for differences in fish travel times and tag lives increased the dam-passage survival estimate for yearling Chinook salmon by 0.0001 and for juvenile steelhead by 0.0004. The estimate was unchanged for subyearling Chinook salmon. The tag-life-adjusted dam-passage survival estimates from our analyses were 0.9641 (standard error [SE] 0.0096) for yearling Chinook salmon, 0.9534 (SE 0.0097) for juvenile steelhead, and 0.9404 (SE 0.0091) for subyearling Chinook salmon. These were within 0.0001 of estimates made by the University of Washington using the ATLAS software. Contrary to the intent of the virtual/paired-release model to adjust estimates of the paired-release model downward in order to account for differential handling mortality rates between release groups, random variation in survival estimates may result in an upward adjustment of survival relative to estimates from the paired-release model. Further investigation of this property of the virtual/paired-release model likely would prove beneficial. In addition, we suggest that differential selective pressures near release sites of the two control groups could bias estimates of dam-passage survival from the virtual/paired-release model.

Dispersal of Engineered Male Aedes aegypti Mosquitoes.

PubMed

Winskill, Peter; Carvalho, Danilo O; Capurro, Margareth L; Alphey, Luke; Donnelly, Christl A; McKemey, Andrew R

2015-11-01

Aedes aegypti, the principal vector of dengue fever, have been genetically engineered for use in a sterile insect control programme. To improve our understanding of the dispersal ecology of mosquitoes and to inform appropriate release strategies of 'genetically sterile' male Aedes aegypti detailed knowledge of the dispersal ability of the released insects is needed. The dispersal ability of released 'genetically sterile' male Aedes aegypti at a field site in Brazil has been estimated. Dispersal kernels embedded within a generalized linear model framework were used to analyse data collected from three large scale mark release recapture studies. The methodology has been applied to previously published dispersal data to compare the dispersal ability of 'genetically sterile' male Aedes aegypti in contrasting environments. We parameterised dispersal kernels and estimated the mean distance travelled for insects in Brazil: 52.8 m (95% CI: 49.9 m, 56.8 m) and Malaysia: 58.0 m (95% CI: 51.1 m, 71.0 m). Our results provide specific, detailed estimates of the dispersal characteristics of released 'genetically sterile' male Aedes aegypti in the field. The comparative analysis indicates that despite differing environments and recapture rates, key features of the insects' dispersal kernels are conserved across the two studies. The results can be used to inform both risk assessments and release programmes using 'genetically sterile' male Aedes aegypti.

Roles of survival and dispersal in reintroduction success of Griffon vulture (Gyps fulvus).

PubMed

Le Gouar, Pascaline; Robert, Alexandre; Choisy, Jean-Pierre; Henriquet, Sylvain; Lecuyer, Philippe; Tessier, Christian; Sarrazin, François

2008-06-01

The success of reintroduction programs greatly depends on the amount of mortality and dispersal of the released individuals. Although local environmental pressures are likely to play an important role in these processes, they have rarely been investigated because of the lack of spatial replicates of reintroduction. In the present study, we analyzed a 25-year data set encompassing 272 individuals released in five reintroduction programs of Griffon Vultures (Gyps fulvus) in France to examine the respective roles of survival and dispersal in program successes and failures. We use recent developments in multi-strata capture-recapture models to take into account tag loss in survival estimates and to consider and estimate dispersal among release areas. We also examined the effects of sex, age, time, area, and release status on survival, and we tested whether dispersal patterns among release areas were consistent with habitat selection theories. Results indicated that the survival of released adults was reduced during the first year after release, with no difference between sexes. Taking into account local observations only, we found that early survival rates varied across sites. However when we distinguished dispersal from mortality, early survival rates became equal across release sites. It thus appears that among reintroduction programs difference in failure and success was due to differential dispersal among release sites. We revealed asymmetrical patterns of dispersal due to conspecific attraction: dispersers selected the closest and the largest population. We showed that mortality can be homogeneous from one program to another while, on the contrary, dispersal is highly dependent on the matrix of established populations. Dispersal behavior is thus of major interest for metapopulation restoration and should be taken into account in planning reintroduction designs.

Observation of the Kaiser Effect Using Noble Gas Release Signals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Stephen J.

The Kaiser effect was defined in the early 1950s (Kaiser 1953) and was extensively reviewed and evaluated by Lavrov (2002) with a view toward understanding stress estimations. The Kaiser effect is a stress memory phenomenon which has most often been demonstrated in rock using acoustic emissions. During cyclic loading–unloading–reloading, the acoustic emissions are near zero until the load exceeds the level of the previous load cycle. Here, we sought to explore the Kaiser effect in rock using real-time noble gas release. Laboratory studies using real-time mass spectrometry measurements during deformation have quantified, to a degree, the types of gases releasedmore » (Bauer et al. 2016a, b), their release rates and amounts during deformation, estimates of permeability created from pore structure modifications during deformation (Gardner et al. 2017) and the impact of mineral plasticity upon gas release. We found that noble gases contained in brittle crystalline rock are readily released during deformation.« less

Observation of the Kaiser Effect Using Noble Gas Release Signals

DOE PAGES

Bauer, Stephen J.

2017-10-24

The Kaiser effect was defined in the early 1950s (Kaiser 1953) and was extensively reviewed and evaluated by Lavrov (2002) with a view toward understanding stress estimations. The Kaiser effect is a stress memory phenomenon which has most often been demonstrated in rock using acoustic emissions. During cyclic loading–unloading–reloading, the acoustic emissions are near zero until the load exceeds the level of the previous load cycle. Here, we sought to explore the Kaiser effect in rock using real-time noble gas release. Laboratory studies using real-time mass spectrometry measurements during deformation have quantified, to a degree, the types of gases releasedmore » (Bauer et al. 2016a, b), their release rates and amounts during deformation, estimates of permeability created from pore structure modifications during deformation (Gardner et al. 2017) and the impact of mineral plasticity upon gas release. We found that noble gases contained in brittle crystalline rock are readily released during deformation.« less

Bayesian estimation of a source term of radiation release with approximately known nuclide ratios

NASA Astrophysics Data System (ADS)

Tichý, Ondřej; Šmídl, Václav; Hofman, Radek

2016-04-01

We are concerned with estimation of a source term in case of an accidental release from a known location, e.g. a power plant. Usually, the source term of an accidental release of radiation comprises of a mixture of nuclide. The gamma dose rate measurements do not provide a direct information on the source term composition. However, physical properties of respective nuclide (deposition properties, decay half-life) can be used when uncertain information on nuclide ratios is available, e.g. from known reactor inventory. The proposed method is based on linear inverse model where the observation vector y arise as a linear combination y = Mx of a source-receptor-sensitivity (SRS) matrix M and the source term x. The task is to estimate the unknown source term x. The problem is ill-conditioned and further regularization is needed to obtain a reasonable solution. In this contribution, we assume that nuclide ratios of the release is known with some degree of uncertainty. This knowledge is used to form the prior covariance matrix of the source term x. Due to uncertainty in the ratios the diagonal elements of the covariance matrix are considered to be unknown. Positivity of the source term estimate is guaranteed by using multivariate truncated Gaussian distribution. Following Bayesian approach, we estimate all parameters of the model from the data so that y, M, and known ratios are the only inputs of the method. Since the inference of the model is intractable, we follow the Variational Bayes method yielding an iterative algorithm for estimation of all model parameters. Performance of the method is studied on simulated 6 hour power plant release where 3 nuclide are released and 2 nuclide ratios are approximately known. The comparison with method with unknown nuclide ratios will be given to prove the usefulness of the proposed approach. This research is supported by EEA/Norwegian Financial Mechanism under project MSMT-28477/2014 Source-Term Determination of Radionuclide Releases by Inverse Atmospheric Dispersion Modelling (STRADI).

A Tunable, Biodegradable, Thin-Film Polymer Device as a Long-Acting Implant Delivering Tenofovir Alafenamide Fumarate for HIV Pre-exposure Prophylaxis

PubMed Central

Schlesinger, Erica; Johengen, Daniel; Luecke, Ellen; Rothrock, Ginger; McGowan, Ian; van der Straten, Ariane; Desai, Tejal

2016-01-01

Purpose The effectiveness of Tenofovir based HIV pre-exposure prophylaxis (PrEP) is proven, but hinges on correct and consistent use. User compliance and therapeutic effectiveness can be improved by long acting drug delivery systems. Here we describe a thin-film polymer device (TFPD) as a biodegradable subcutaneous implant for PrEP. Methods A thin-film polycaprolactone (PCL) membrane controls drug release from a reservoir. To achieve membrane controlled release, TAF requires a formulation excipient such as PEG300 to increase the dissolution rate and reservoir solubility. Short-term In vitro release studies are used to develop an empirical design model, which is applied to the production of in vitro prototype devices demonstrating up to 90-days of linear release and TAF chemical stability. Results The size and shape of the TFPD are tunable, achieving release rates ranging from 0.5–4.4 mg/day in devices no larger than a contraceptive implant. Based on published data for oral TAF, subcutaneous constant-rate release for HIV PrEP is estimated at < 2.8mg/day. Prototype devices demonstrated linear release at 1.2mg/day for up to 90 days and at 2.2mg/day for up to 60 days. Conclusions We present a biodegradable TFPD for subcutaneous delivery of TAF for HIV PrEP. The size, shape and release rate of the device are tunable over a > 8-fold range. PMID:26975357

Potential third-party radiation exposure from patients undergoing therapy with 131I for thyroid cancer or metastases.

PubMed

D'Alessio, Daniela; Giliberti, Claudia; Benassi, Marcello; Strigari, Lidia

2015-03-01

The purpose of this work is to evaluate the potential third-party radiation exposure from patients undergoing therapy with 131I for ablation of residual thyroid tumor or metastases, based in part on serial measurements of exposure rates. Exposure rate measurements were performed at 1 m and 5 cm from the surface of each treated patient until patient release. Dose estimates based on measured exposure rates were compared with those based on analytic point-source (PSM) and line-source (LSM) models. Effective doses D(∞) to travelers, co-workers and sleeping partners were estimated by using the standard gamma factor (Γ) and the physical half-life or the values derived from measured data. Seven hundred ten patients were studied until the exposure at 1 m was below the constraints of 0.010 mSv. The 131I activities administered ranged from 1.85 to 11.0 GBq (median: 3.7 GBq), according to the therapeutic requirements. Based on the PSM and an experimental Γ, the mean/maximum estimated D(∞) to sleeping partners, partners, travelers, and co-workers were 2.60/20.65, 0.32/2.53, 0.96/7.59, and 0.57/4.50 mSv, respectively. Using the LSM and an experimental Γ, the D(∞) values were 2.41/19.15, 0.32/2.50, 0.83/6.62, and 0.57/4.42 mSv, respectively, while they were almost double using the theoretical Γ. The results presented, based on measured data in a large cohort of 131I-treated thyroid cancer patients, will allow more accurate estimation of potential third-party D(∞) following patient release and thus may be used to better inform physicians and hospital staff on recommendations for patient release and post-release precautions following radioiodine therapies.

Application of the Approximate Bayesian Computation methods in the stochastic estimation of atmospheric contamination parameters for mobile sources

NASA Astrophysics Data System (ADS)

Kopka, Piotr; Wawrzynczak, Anna; Borysiewicz, Mieczyslaw

2016-11-01

In this paper the Bayesian methodology, known as Approximate Bayesian Computation (ABC), is applied to the problem of the atmospheric contamination source identification. The algorithm input data are on-line arriving concentrations of the released substance registered by the distributed sensors network. This paper presents the Sequential ABC algorithm in detail and tests its efficiency in estimation of probabilistic distributions of atmospheric release parameters of a mobile contamination source. The developed algorithms are tested using the data from Over-Land Atmospheric Diffusion (OLAD) field tracer experiment. The paper demonstrates estimation of seven parameters characterizing the contamination source, i.e.: contamination source starting position (x,y), the direction of the motion of the source (d), its velocity (v), release rate (q), start time of release (ts) and its duration (td). The online-arriving new concentrations dynamically update the probability distributions of search parameters. The atmospheric dispersion Second-order Closure Integrated PUFF (SCIPUFF) Model is used as the forward model to predict the concentrations at the sensors locations.

LIGHT NONAQUEOUS-PHASE LIQUID HYDROCARBON WEATHERING AT SOME JP-4 FUEL RELEASE SITES

EPA Science Inventory

A fuel weathering study was conducted for database entries to estimate natural light, nonaqueousphase
liquid weathering and source-term reduction rates for use in natural attenuation models. A range of BTEX
weathering rates from mobile LNAPL plumes at eight field sites with...

Evaluation of stream flow effects on smolt survival in the Yakima River basin, Washington

USGS Publications Warehouse

Courter,; Garrison,; Kock, Tobias J.; Perry, Russell W.

2012-01-01

Yearling Chinook smolt survival and travel time estimates from 2012 suggest that migration rates and survival rates in the Roza Reach may be associated with stream flow, water temperature, release timing (i.e. migratory disposition), and fish size, but the extent to which each variable influenced survival is yet to be determined. The lowest survival rate (61%) and longest travel time (median 2.26 days) was observed in Release Group 1, which had the smallest size distribution and experienced the lowest flows, lowest temperatures, and earliest release date among the three groups. Release Groups 2 and 3 survived at 96% and 98% respectively and traveled through the Roza Reach in less than eight hours. The primary focus of years two and three of this study will be to collect data that minimizes the effect of confounding explanatory variables, so that flow effects on emigration survival can be quantified independent of these other influential factors.

Maximum earthquake magnitudes in the Aegean area constrained by tectonic moment release rates

NASA Astrophysics Data System (ADS)

Ch. Koravos, G.; Main, I. G.; Tsapanos, T. M.; Musson, R. M. W.

2003-01-01

Seismic moment release is usually dominated by the largest but rarest events, making the estimation of seismic hazard inherently uncertain. This uncertainty can be reduced by combining long-term tectonic deformation rates with short-term recurrence rates. Here we adopt this strategy to estimate recurrence rates and maximum magnitudes for tectonic zones in the Aegean area. We first form a merged catalogue for historical and instrumentally recorded earthquakes in the Aegean, based on a recently published catalogue for Greece and surrounding areas covering the time period 550BC-2000AD, at varying degrees of completeness. The historical data are recalibrated to allow for changes in damping in seismic instruments around 1911. We divide the area up into zones that correspond to recent determinations of deformation rate from satellite data. In all zones we find that the Gutenberg-Richter (GR) law holds at low magnitudes. We use Akaike's information criterion to determine the best-fitting distribution at high magnitudes, and classify the resulting frequency-magnitude distributions of the zones as critical (GR law), subcritical (gamma density distribution) or supercritical (`characteristic' earthquake model) where appropriate. We determine the ratio η of seismic to tectonic moment release rate. Low values of η (<0.5) corresponding to relatively aseismic deformation, are associated with higher b values (>1.0). The seismic and tectonic moment release rates are then combined to constrain recurrence rates and maximum credible magnitudes (in the range 6.7-7.6 mW where the results are well constrained) based on extrapolating the short-term seismic data. With current earthquake data, many of the tectonic zones show a characteristic distribution that leads to an elevated probability of magnitudes around 7, but a reduced probability of larger magnitudes above this value when compared with the GR trend. A modification of the generalized gamma distribution is suggested to account for this, based on a finite statistical second moment for the seismic moment distribution.

Behavioral aspects of Lutzomyia longipalpis (Diptera: Psychodidae) in urban area endemic for visceral leishmaniasis.

PubMed

De Oliveira, E F; Silva, E A; Casaril, A E; Fernandes, C E S; Paranhos Filho, A C; Gamarra, R M; Ribeiro, A A; Brazil, R P; Oliveira, A G

2013-03-01

The study of some of the behavioral aspects of the main vector of Leishmania infantum chagasi Cunha & Chagas in the Americas, Lutzomyia longipalpis (Lutz & Neiva), such as dispersion, population size, and vector survival rates, is important for the elucidation of the mechanisms of visceral leishmaniasis transmission. These parameters were studied by means of capture-mark-release-recapture experiments in an urban area of Campo Grande municipality, an endemic area of visceral leishmaniasis, situated in Mato Grosso do Sul state, Brazil. Six capture-mark-release-recapture experiments were undertaken between November 2009 and November 2010 and once in January 2012 with a view to assessing the population size and survival rate of Lu. longipalpis. The insects were released in a peridomicile surrounded by 13 residences. The recaptures were undertaken with automatic light traps for four consecutive weeks after release in the surrounding area. In total, 3,354 sand flies were captured, marked, and released. The overall recapture rate during the capture-mark-release-recapture experiments was 4.23%, of which 92.45% were recaptured at the release site, indicating limited dispersal. The greatest distance recorded from the release site was 165 m for males and 241 m for females. The male daily survival rate, calculated on the basis of regressions from the numbers of marked recaptured insects during the 15 successive days after release was 0.897. The estimated male population size measured by the Lincoln Index was 10,947.127. Though Lu. longipalpis presented a limited dispersion the physical barriers typical of urban environments did not prevent the sand flies from flying long distances.

Transit losses and traveltimes for water-supply releases Marion Lake during drought conditions, Cottonwood River, east-central Kansas

USGS Publications Warehouse

Jordan, P.R.; Hart, R.J.

1985-01-01

A streamflow routing model was used to calculate the transit losses and traveltimes. Channel and aquifer characteristics, and the model control parameters, were estimated from available data and then verified to the extent possible by comparing model simulated streamflow to observed streamflow at streamflow gaging stations. Transit losses and traveltimes for varying reservoir release rates and durations then were simulated for two different antecedent streamflow (drought) conditions. For the severe-drought antecedent-streamflow condition, it was assumed that only the downstream water use requirement would be released from the reservoir. For a less severe drought (LSD) antecedent streamflow condition, it was assumed than any releases from Marion Lake for water supply use downstream, would be in addition to a nominal dry weather release of 5 cu ft/sec. Water supply release rates of 10 and 25 cu ft/sec for the severe drought condition and 5, 10, and 25 cu ft/sec for the less severe drought condition were simulated for periods of 28 and 183 days commencing on July 1. Transit losses for the severe drought condition for all reservoir release rates and durations ranged from 12% to 78% of the maximum downstream flow rate and from 27% to 91% of the total volume of reservoir storage released. For the LSD condition, transit losses ranged from 7% to 29% of the maximum downstream flow rate and from 10% to 48% of the total volume of release. The 183-day releases had larger total transit losses, but losses on a percentage basis were less than the losses for the 28-day release period for both antecedent streamflow conditions. Traveltimes to full response (80% of the maximum downstream flow rate), however, showed considerable variation. For the release of 5 cu ft/sec during LSD conditions, base flow exceeded 80% of the maximum flow rate near the confluence; the traveltime to full response was undefined for those simulations. For the releases of 10 and 25 cu ft/sec during the same drought condition, traveltimes to full response ranged from 4.4 to 6.5 days. For releases of 10 and 25 cu ft/sec during severe drought conditions, traveltimes to full response near the confluence with the Neosho River ranged from 8.3 to 93 days. (Lantz-PTT)

Endangered Right Whales Enhance Primary Productivity in the Bay of Fundy

PubMed Central

Roman, Joe; Nevins, John; Altabet, Mark; Koopman, Heather; McCarthy, James

2016-01-01

Marine mammals have recently been documented as important facilitators of rapid and efficient nutrient recycling in coastal and offshore waters. Whales enhance phytoplankton nutrition by releasing fecal plumes near the surface after feeding and by migrating from highly productive, high-latitude feeding areas to low-latitude nutrient-poor calving areas. In this study, we measured NH4+ and PO43- release rates from the feces of North Atlantic right whales (Eubalaena glacialis), a highly endangered baleen whale. Samples for this species were primarily collected by locating aggregations of whales in surface-active groups (SAGs), which typically consist of a central female surrounded by males competing for sexual activity. When freshly collected feces were incubated in seawater, high initial rates of N release were generally observed, which decreased to near zero within 24 hours of sampling, a pattern that is consistent with the active role of gut microflora on fecal particles. We estimate that at least 10% of particulate N in whale feces becomes available as NH4+ within 24 hours of defecation. Phosphorous was also abundant in fecal samples: initial release rates of PO43- were higher than for NH4+, yielding low N/P nutrient ratios over the course of our experiments. The rate of PO43- release was thus more than sufficient to preclude the possibility that nitrogenous nutrients supplied by whales would lead to phytoplankton production limited by P availability. Phytoplankton growth experiments indicated that NH4+ released from whale feces enhance productivity, as would be expected, with no evidence that fecal metabolites suppress growth. Although North Atlantic right whales are currently rare (approximately 450 individuals), they once numbered about 14,000 and likely played a substantial role in recycling nutrients in areas where they gathered to feed and mate. Even though the NH4+ released from fresh whale fecal material is a small fraction of total whale fecal nitrogen, and recognizing the fact that the additional nitrogen released in whale urine would be difficult to measure in a field study, the results of this study support the idea that the distinctive isotopic signature of the released NH4+ could be used to provide a conservative estimate of the contribution of the whale pump to primary productivity in coastal regions where whales congregate. PMID:27331902

Endangered Right Whales Enhance Primary Productivity in the Bay of Fundy.

PubMed

Roman, Joe; Nevins, John; Altabet, Mark; Koopman, Heather; McCarthy, James

2016-01-01

Marine mammals have recently been documented as important facilitators of rapid and efficient nutrient recycling in coastal and offshore waters. Whales enhance phytoplankton nutrition by releasing fecal plumes near the surface after feeding and by migrating from highly productive, high-latitude feeding areas to low-latitude nutrient-poor calving areas. In this study, we measured NH4+ and PO43- release rates from the feces of North Atlantic right whales (Eubalaena glacialis), a highly endangered baleen whale. Samples for this species were primarily collected by locating aggregations of whales in surface-active groups (SAGs), which typically consist of a central female surrounded by males competing for sexual activity. When freshly collected feces were incubated in seawater, high initial rates of N release were generally observed, which decreased to near zero within 24 hours of sampling, a pattern that is consistent with the active role of gut microflora on fecal particles. We estimate that at least 10% of particulate N in whale feces becomes available as NH4+ within 24 hours of defecation. Phosphorous was also abundant in fecal samples: initial release rates of PO43- were higher than for NH4+, yielding low N/P nutrient ratios over the course of our experiments. The rate of PO43- release was thus more than sufficient to preclude the possibility that nitrogenous nutrients supplied by whales would lead to phytoplankton production limited by P availability. Phytoplankton growth experiments indicated that NH4+ released from whale feces enhance productivity, as would be expected, with no evidence that fecal metabolites suppress growth. Although North Atlantic right whales are currently rare (approximately 450 individuals), they once numbered about 14,000 and likely played a substantial role in recycling nutrients in areas where they gathered to feed and mate. Even though the NH4+ released from fresh whale fecal material is a small fraction of total whale fecal nitrogen, and recognizing the fact that the additional nitrogen released in whale urine would be difficult to measure in a field study, the results of this study support the idea that the distinctive isotopic signature of the released NH4+ could be used to provide a conservative estimate of the contribution of the whale pump to primary productivity in coastal regions where whales congregate.

Using strain rates to forecast seismic hazards

USGS Publications Warehouse

Evans, Eileen

2017-01-01

One essential component in forecasting seismic hazards is observing the gradual accumulation of tectonic strain accumulation along faults before this strain is suddenly released as earthquakes. Typically, seismic hazard models are based on geologic estimates of slip rates along faults and historical records of seismic activity, neither of which records actively accumulating strain. But this strain can be estimated by geodesy: the precise measurement of tiny position changes of Earth’s surface, obtained from GPS, interferometric synthetic aperture radar (InSAR), or a variety of other instruments.

Measurement of greenhouse gas emissions from agricultural sites using open-path optical remote sensing method.

PubMed

Ro, Kyoung S; Johnson, Melvin H; Varma, Ravi M; Hashmonay, Ram A; Hunt, Patrick

2009-08-01

Improved characterization of distributed emission sources of greenhouse gases such as methane from concentrated animal feeding operations require more accurate methods. One promising method is recently used by the USEPA. It employs a vertical radial plume mapping (VRPM) algorithm using optical remote sensing techniques. We evaluated this method to estimate emission rates from simulated distributed methane sources. A scanning open-path tunable diode laser was used to collect path-integrated concentrations (PICs) along different optical paths on a vertical plane downwind of controlled methane releases. Each cycle consists of 3 ground-level PICs and 2 above ground PICs. Three- to 10-cycle moving averages were used to reconstruct mass equivalent concentration plum maps on the vertical plane. The VRPM algorithm estimated emission rates of methane along with meteorological and PIC data collected concomitantly under different atmospheric stability conditions. The derived emission rates compared well with actual released rates irrespective of atmospheric stability conditions. The maximum error was 22 percent when 3-cycle moving average PICs were used; however, it decreased to 11% when 10-cycle moving average PICs were used. Our validation results suggest that this new VRPM method may be used for improved estimations of greenhouse gas emission from a variety of agricultural sources.

Refining Field Measurements of Methane Flux Rates from Abandoned Oil and Gas Wells

NASA Astrophysics Data System (ADS)

Lagron, C. S.; Kang, M.; Riqueros, N. S.; Jackson, R. B.

2015-12-01

Recent studies in Pennsylvania demonstrate the potential for significant methane emissions from abandoned oil and gas wells. A subset of tested wells was high emitting, with methane flux rates up to seven orders of magnitude greater than natural fluxes (up to 105 mg CH4/hour, or about 2.5LPM). These wells contribute disproportionately to the total methane emissions from abandoned oil and gas wells. The principles guiding the chamber design have been developed for lower flux rates, typically found in natural environments, and chamber design modifications may reduce uncertainty in flux rates associated with high-emitting wells. Kang et al. estimate errors of a factor of two in measured values based on previous studies. We conduct controlled releases of methane to refine error estimates and improve chamber design with a focus on high-emitters. Controlled releases of methane are conducted at 0.05 LPM, 0.50 LPM, 1.0 LPM, 2.0 LPM, 3.0 LPM, and 5.0 LPM, and at two chamber dimensions typically used in field measurements studies of abandoned wells. As most sources of error tabulated by Kang et al. tend to bias the results toward underreporting of methane emissions, a flux-targeted chamber design modification can reduce error margins and/or provide grounds for a potential upward revision of emission estimates.

In situ lifetimes and kinetics of a reductive whey barrier and an oxidative ORC barrier in the subsurface.

PubMed

Barcelona, M J; Xie, G

2001-08-15

Permeable reactive barriers (PRB) are being used to engineer favorable field conditions for in-situ remediation efforts. Two redox adjustment barriers were installed to facilitate a 10-month research effort on the fate and transport of MTBE (methyl tert-butyl ether) at a site called the Michigan Integrated Remediation Technology Laboratory (MIRTL). Thirty kilograms of whey were injected as a slurry into an unconfined aquifer to establish an upgradient reductive zone to reduce O2 concentration in the vicinity of a contaminant injection source. To minimize the impact of contaminant release, 363 kg of oxygen release compound (ORC) were placed in the aquifer as a downgradient oxidative barrier. Dissolved oxygen and other chemical species were monitored in the field to evaluate the effectiveness of this technology. A transient one-dimensional advective-dispersive-reaction (ADR) model was proposed to simulate the dissolved oxygen transport. The equations were solved with commonly encountered PRB initial and constant/variable boundary conditions. No similar previous solution was found in the literature. The in-situ lifetimes, based on variable source loading, were estimated to be 1,661 and 514 days for the whey barrier and ORC barrier, respectively. Estimates based on either maximum O2 consumption/production or measured O2 curves were found to under- or overestimate the lifetime of the barriers. The pseudo-first-order rate constant of whey depletion was estimated to be 0.303/d with a dissolution rate of 0.04/d. The oxygen release rate constant in the ORC barrier was estimated to be 0.03/d. This paper provides a means to design and predict the performance of reactive redox barriers, especially when only limited field data are available.

Estimation of point source fugitive emission rates from a single sensor time series: a conditionally-sampled Gaussian plume reconstruction

EPA Science Inventory

This paper presents a technique for determining the trace gas emission rate from a point source. The technique was tested using data from controlled methane release experiments and from measurement downwind of a natural gas production facility in Wyoming. Concentration measuremen...

Inverse modelling for real-time estimation of radiological consequences in the early stage of an accidental radioactivity release.

PubMed

Pecha, Petr; Šmídl, Václav

2016-11-01

A stepwise sequential assimilation algorithm is proposed based on an optimisation approach for recursive parameter estimation and tracking of radioactive plume propagation in the early stage of a radiation accident. Predictions of the radiological situation in each time step of the plume propagation are driven by an existing short-term meteorological forecast and the assimilation procedure manipulates the model parameters to match the observations incoming concurrently from the terrain. Mathematically, the task is a typical ill-posed inverse problem of estimating the parameters of the release. The proposed method is designated as a stepwise re-estimation of the source term release dynamics and an improvement of several input model parameters. It results in a more precise determination of the adversely affected areas in the terrain. The nonlinear least-squares regression methodology is applied for estimation of the unknowns. The fast and adequately accurate segmented Gaussian plume model (SGPM) is used in the first stage of direct (forward) modelling. The subsequent inverse procedure infers (re-estimates) the values of important model parameters from the actual observations. Accuracy and sensitivity of the proposed method for real-time forecasting of the accident propagation is studied. First, a twin experiment generating noiseless simulated "artificial" observations is studied to verify the minimisation algorithm. Second, the impact of the measurement noise on the re-estimated source release rate is examined. In addition, the presented method can be used as a proposal for more advanced statistical techniques using, e.g., importance sampling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tagging methods for estimating population size and mortality rates of inland striped bass populations

USGS Publications Warehouse

Hightower, Joseph E.; Pollock, Kenneth H.

2013-01-01

Striped bass Morone saxatilis in inland reservoirs play an important role ecologically and in supporting recreational fishing. To manage these populations, biologists need information about abundance and mortality. Abundance estimates can be used to assess the effectiveness of stocking programs that maintain most reservoir striped bass populations. Mortality estimates can indicate the relative impact of fishing versus natural mortality and the need for harvest regulation. The purpose of this chapter is to evaluate tagging studies as a way of obtaining information about abundance and mortality. These approaches can be grouped into three broad categories: tag recapture, tag return, and telemetry. Tag-recapture methods are typically used to estimate population size and other demographic parameters but are often difficult to apply in large systems. A fishing tournament can be an effective way of generating tagging or recapture effort in large systems, compared to using research sampling only. Tag-return methods that rely on angler harvest and catch and release can be used to estimate fishing (F) and natural (M) mortality rates and are a practical approach in large reservoirs. The key to success in tag-return studies is to build in auxiliary studies to estimate short-term tagging mortality, short- and longterm tag loss, reporting rate, and mortality associated with catch and release. F and M can also be estimated using telemetry tags. Advantages of this approach are that angler nonreporting does not bias estimates and fish with transmitters provide useful ecological data. Cost can be a disadvantage of telemetry studies; thus, combining telemetry tags with conventional tag returns in an integrated analysis is often the optimal approach. In summary, tagging methods can be a powerful tool for assessing the effectiveness of inland striped bass stocking programs and the relative impact of fishing versus natural mortality

High dissolved organic carbon release by benthic cyanobacterial mats in a Caribbean reef ecosystem

NASA Astrophysics Data System (ADS)

Brocke, Hannah J.; Wenzhoefer, Frank; de Beer, Dirk; Mueller, Benjamin; van Duyl, Fleur C.; Nugues, Maggy M.

2015-03-01

Benthic cyanobacterial mats (BCMs) are increasing in abundance on coral reefs worldwide. However, their impacts on biogeochemical cycling in the surrounding water and sediment are virtually unknown. By measuring chemical fluxes in benthic chambers placed over sediment covered by BCMs and sediment with BCMs removed on coral reefs in Curaçao, Southern Caribbean, we found that sediment covered by BCMs released 1.4 and 3.5 mmol C m-2 h-1 of dissolved organic carbon (DOC) during day and night, respectively. Conversely, sediment with BCMs removed took up DOC, with day and night uptake rates of 0.9 and 0.6 mmol C m-2 h-1. DOC release by BCMs was higher than reported rates for benthic algae (turf and macroalgae) and was estimated to represent 79% of the total DOC released over a 24 h diel cycle at our study site. The high nocturnal release of DOC by BCMs is most likely the result of anaerobic metabolism and degradation processes, as shown by high respiration rates at the mat surface during nighttime. We conclude that BCMs are significant sources of DOC. Their increased abundance on coral reefs will lead to increased DOC release into the water column, which is likely to have negative implications for reef health.

High dissolved organic carbon release by benthic cyanobacterial mats in a Caribbean reef ecosystem.

PubMed

Brocke, Hannah J; Wenzhoefer, Frank; de Beer, Dirk; Mueller, Benjamin; van Duyl, Fleur C; Nugues, Maggy M

2015-03-09

Benthic cyanobacterial mats (BCMs) are increasing in abundance on coral reefs worldwide. However, their impacts on biogeochemical cycling in the surrounding water and sediment are virtually unknown. By measuring chemical fluxes in benthic chambers placed over sediment covered by BCMs and sediment with BCMs removed on coral reefs in Curaçao, Southern Caribbean, we found that sediment covered by BCMs released 1.4 and 3.5 mmol C m(-2) h(-1) of dissolved organic carbon (DOC) during day and night, respectively. Conversely, sediment with BCMs removed took up DOC, with day and night uptake rates of 0.9 and 0.6 mmol C m(-2) h(-1). DOC release by BCMs was higher than reported rates for benthic algae (turf and macroalgae) and was estimated to represent 79% of the total DOC released over a 24 h diel cycle at our study site. The high nocturnal release of DOC by BCMs is most likely the result of anaerobic metabolism and degradation processes, as shown by high respiration rates at the mat surface during nighttime. We conclude that BCMs are significant sources of DOC. Their increased abundance on coral reefs will lead to increased DOC release into the water column, which is likely to have negative implications for reef health.

Estimating accidental pollutant releases in the built environment from turbulent concentration signals

NASA Astrophysics Data System (ADS)

Ben Salem, N.; Salizzoni, P.; Soulhac, L.

2017-01-01

We present an inverse atmospheric model to estimate the mass flow rate of an impulsive source of pollutant, whose position is known, from concentration signals registered at receptors placed downwind of the source. The originality of this study is twofold. Firstly, the inversion is performed using high-frequency fluctuating, i.e. turbulent, concentration signals. Secondly, the inverse algorithm is applied to a dispersion process within a dense urban canopy, at the district scale, and a street network model, SIRANERISK, is adopted. The model, which is tested against wind tunnel experiments, simulates the dispersion of short-duration releases of pollutant in different typologies of idealised urban geometries. Results allow us to discuss the reliability of the inverse model as an operational tool for crisis management and the risk assessments related to the accidental release of toxic and flammable substances.

Toxic exposure in America: estimating fetal and infant health outcomes from 14 years of TRI reporting.

PubMed

Agarwal, Nikhil; Banternghansa, Chanont; Bui, Linda T M

2010-07-01

We examine the effect of exposure to a set of toxic pollutants that are tracked by the Toxic Release Inventory (TRI) from manufacturing facilities on county-level infant and fetal mortality rates in the United States between 1989 and 2002. Unlike previous studies, we control for toxic pollution from both mobile sources and non-TRI reporting facilities. We find significant adverse effects of toxic air pollution concentrations on infant mortality rates. Within toxic air pollutants we find that releases of carcinogens are particularly problematic for infant health outcomes. We estimate that the average county-level decreases in various categories of TRI concentrations saved in excess of 13,800 infant lives from 1989 to 2002. Using the low end of the range for the value of a statistical life that is typically used by the EPA of $1.8M, the savings in lives would be valued at approximately $25B.

A Novel Method for Characterizing Fatigue Delamination Growth Under Mode I Using the Double Cantilever Beam Specimen

NASA Technical Reports Server (NTRS)

Carvalho, Nelson; Murri, G.

2014-01-01

A novel method is proposed to obtain Mode I delamination growth rate from a Double Cantilever Beam (DCB) specimen. In the proposed method, Unidirectional (UD) DCB specimens are tested in fatigue at different initial maximum energy release rates levels. The growth rate data obtained in the first increments of crack growth at each maximum energy release rate level are used to generate a Paris Law equation, which characterizes delamination growth rate without fiber-bridging, and can also be used to determine a delamination onset curve. The remaining delamination growth rate data from each test are used to determine a modified Paris law, which characterizes the delamination growth rate in a DCB specimen, explicitly accounting for fiber-bridging. The proposed expression captures well the scatter in experimental data obtained using the DCB specimens, suggesting its adequacy. The Paris Law characterizing delamination growth rate without fiber-bridging predicts higher delamination growth rates for the same maximum energy release rate applied, leading to a conservative estimate for delamination growth. This is particularly relevant, since in generic ply interfaces, fiber-bridging is less predominant than in UD DCB specimens. Failing to account for fiber-bridging in UD DCB specimens may underestimate the delamination growth rate, yielding non-conservative predictions.

NESHAP Area-Specific Dose-Release Factors for Potential Onsite Member-of-the-Public Locations at SRS using CAP88-PC Version 4.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trimor, P.

The Environmental Protection Agency (EPA) requires the use of the computer model CAP88-PC to estimate the total effective doses (TED) for demonstrating compliance with 40 CFR 61, Subpart H (EPA 2006), the National Emission Standards for Hazardous Air Pollutants (NESHAP) regulations. As such, CAP88 Version 4.0 was used to calculate the receptor dose due to routine atmospheric releases at the Savannah River Site (SRS). For estimation, NESHAP dose-release factors (DRFs) have been supplied to Environmental Compliance and Area Closure Projects (EC&ACP) for many years. DRFs represent the dose to a maximum receptor exposed to 1 Ci of a specified radionuclidemore » being released into the atmosphere. They are periodically updated to include changes in the CAP88 version, input parameter values, site meteorology, and location of the maximally exposed individual (MEI). In this report, the DRFs were calculated for potential radionuclide atmospheric releases from 13 SRS release points. The three potential onsite MEI locations to be evaluated are B-Area, Three Rivers Landfill (TRL), and Savannah River Ecology Lab Conference Center (SRELCC) with TRL’s onsite workers considered as members-of-the-public, and the potential future constructions of dormitories at SRELCC and Barracks at B-Area. Each MEI location was evaluated at a specified compass sector with different area to receptor distances and was conducted for both ground-level and elevated release points. The analysis makes use of area-specific meteorological data (Viner 2014). The resulting DRFs are compared to the 2014 NESHAP offsite MEI DRFs for three operational areas; A-Area, H-Area, and COS for a release rate of 1 Ci of tritium oxide at 0 ft. elevation. CAP88 was executed again using the 2016 NESHAP MEI release rates for 0 and 61 m stack heights to determine the radionuclide dose at TRL from the center-of-site (COS).« less

Evaluating release alternatives for a long-lived bird species under uncertainty about long-term demographic rates

USGS Publications Warehouse

Moore, Clinton T.; Converse, Sarah J.; Folk, Martin J.; Runge, Michael C.; Nesbitt, Stephen A.

2012-01-01

The release of animals to reestablish an extirpated population is a decision problem that is often attended by considerable uncertainty about the probability of success. Annual releases of captive-reared juvenile Whooping Cranes (Grus americana) were begun in 1993 in central Florida, USA, to establish a breeding, non-migratory population. Over a 12-year period, 286 birds were released, but by 2004, the introduced flock had produced only four wild-fledged birds. Consequently, releases were halted over managers' concerns about the performance of the released flock and uncertainty about the efficacy of further releases. We used data on marked, released birds to develop predictive models for addressing whether releases should be resumed, and if so, under what schedule. To examine the outcome of different release scenarios, we simulated the survival and productivity of individual female birds under a baseline model that recognized age and breeding-class structure and which incorporated empirically estimated stochastic elements. As data on wild-fledged birds from captive-reared parents were sparse, a key uncertainty that confronts release decision-making is whether captive-reared birds and their offspring share the same vital rates. Therefore, we used data on the only population of wild Whooping Cranes in existence to construct two alternatives to the baseline model. The probability of population persistence was highly sensitive to the choice of these three models. Under the baseline model, extirpation of the population was nearly certain under any scenario of resumed releases. In contrast, the model based on estimates from wild birds projected a high probability of persistence under any release scenario, including cessation of releases. Therefore, belief in either of these models suggests that further releases are an ineffective use of resources. In the third model, which simulated a population Allee effect, population persistence was sensitive to the release decision: high persistence probability was achieved only through the release of more birds, whereas extirpation was highly probable with cessation of releases. Despite substantial investment of time and effort in the release program, evidence collected to date does not favor one model over another; therefore, any decision about further releases must be made under considerable biological uncertainty. However, given an assignment of credibility weight to each model, a best, informed decision about releases can be made under uncertainty. Furthermore, if managers can periodically revisit the release decision and collect monitoring data to further inform the models, then managers have a basis for confronting uncertainty and adaptively managing releases through time.

Carbon fiber plume sampling for large scale fire tests at Dugway Proving Ground. [fiber release during aircraft fires

NASA Technical Reports Server (NTRS)

Chovit, A. R.; Lieberman, P.; Freeman, D. E.; Beggs, W. C.; Millavec, W. A.

1980-01-01

Carbon fiber sampling instruments were developed: passive collectors made of sticky bridal veil mesh, and active instruments using a light emitting diode (LED) source. These instruments measured the number or number rate of carbon fibers released from carbon/graphite composite material when the material was burned in a 10.7 m (35 ft) dia JP-4 pool fire for approximately 20 minutes. The instruments were placed in an array suspended from a 305 m by 305 m (1000 ft by 1000 ft) Jacob's Ladder net held vertically aloft by balloons and oriented crosswind approximately 140 meters downwind of the pool fire. Three tests were conducted during which released carbon fiber data were acquired. These data were reduced and analyzed to obtain the characteristics of the released fibers including their spatial and size distributions and estimates of the number and total mass of fibers released. The results of the data analyses showed that 2.5 to 3.5 x 10 to the 8th power single carbon fibers were released during the 20 minute burn of 30 to 50 kg mass of initial, unburned carbon fiber material. The mass released as single carbon fibers was estimated to be between 0.1 and 0.2% of the initial, unburned fiber mass.

Estimation of in-vivo neurotransmitter release by brain microdialysis: the issue of validity.

PubMed

Di Chiara, G.; Tanda, G.; Carboni, E.

1996-11-01

Although microdialysis is commonly understood as a method of sampling low molecular weight compounds in the extracellular compartment of tissues, this definition appears insufficient to specifically describe brain microdialysis of neurotransmitters. In fact, transmitter overflow from the brain into dialysates is critically dependent upon the composition of the perfusing Ringer. Therefore, the dialysing Ringer not only recovers the transmitter from the extracellular brain fluid but is a main determinant of its in-vivo release. Two types of brain microdialysis are distinguished: quantitative micro-dialysis and conventional microdialysis. Quantitative microdialysis provides an estimate of neurotransmitter concentrations in the extracellular fluid in contact with the probe. However, this information might poorly reflect the kinetics of neurotransmitter release in vivo. Conventional microdialysis involves perfusion at a constant rate with a transmitter-free Ringer, resulting in the formation of a steep neurotransmitter concentration gradient extending from the Ringer into the extracellular fluid. This artificial gradient might be critical for the ability of conventional microdialysis to detect and resolve phasic changes in neurotransmitter release taking place in the implanted area. On the basis of these characteristics, conventional microdialysis of neurotransmitters can be conceptualized as a model of the in-vivo release of neurotransmitters in the brain. As such, the criteria of face-validity, construct-validity and predictive-validity should be applied to select the most appropriate experimental conditions for estimating neurotransmitter release in specific brain areas in relation to behaviour.

Detailed source term estimation of the atmospheric release for the Fukushima Daiichi Nuclear Power Station accident by coupling simulations of an atmospheric dispersion model with an improved deposition scheme and oceanic dispersion model

NASA Astrophysics Data System (ADS)

Katata, G.; Chino, M.; Kobayashi, T.; Terada, H.; Ota, M.; Nagai, H.; Kajino, M.; Draxler, R.; Hort, M. C.; Malo, A.; Torii, T.; Sanada, Y.

2015-01-01

Temporal variations in the amount of radionuclides released into the atmosphere during the Fukushima Daiichi Nuclear Power Station (FNPS1) accident and their atmospheric and marine dispersion are essential to evaluate the environmental impacts and resultant radiological doses to the public. In this paper, we estimate the detailed atmospheric releases during the accident using a reverse estimation method which calculates the release rates of radionuclides by comparing measurements of air concentration of a radionuclide or its dose rate in the environment with the ones calculated by atmospheric and oceanic transport, dispersion and deposition models. The atmospheric and oceanic models used are WSPEEDI-II (Worldwide version of System for Prediction of Environmental Emergency Dose Information) and SEA-GEARN-FDM (Finite difference oceanic dispersion model), both developed by the authors. A sophisticated deposition scheme, which deals with dry and fog-water depositions, cloud condensation nuclei (CCN) activation, and subsequent wet scavenging due to mixed-phase cloud microphysics (in-cloud scavenging) for radioactive iodine gas (I2 and CH3I) and other particles (CsI, Cs, and Te), was incorporated into WSPEEDI-II to improve the surface deposition calculations. The results revealed that the major releases of radionuclides due to the FNPS1 accident occurred in the following periods during March 2011: the afternoon of 12 March due to the wet venting and hydrogen explosion at Unit 1, midnight of 14 March when the SRV (safety relief valve) was opened three times at Unit 2, the morning and night of 15 March, and the morning of 16 March. According to the simulation results, the highest radioactive contamination areas around FNPS1 were created from 15 to 16 March by complicated interactions among rainfall, plume movements, and the temporal variation of release rates. The simulation by WSPEEDI-II using the new source term reproduced the local and regional patterns of cumulative surface deposition of total 131I and 137Cs and air dose rate obtained by airborne surveys. The new source term was also tested using three atmospheric dispersion models (Modèle Lagrangien de Dispersion de Particules d'ordre zéro: MLDP0, Hybrid Single Particle Lagrangian Integrated Trajectory Model: HYSPLIT, and Met Office's Numerical Atmospheric-dispersion Modelling Environment: NAME) for regional and global calculations, and the calculated results showed good agreement with observed air concentration and surface deposition of 137Cs in eastern Japan.

Design and Analysis of Salmonid Tagging Studies in the Columbia Basin, Volume XIII; Appraisal of System-Wide Survival Estimation of Snake River Yearling Chinook Salmon Released in 1997 and 1988, Using PIT-Tags Recovered from Caspian Tern and Double-Crested Cormorant Breeding Colonies on Rice Island, 1997-1998 Technical Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skalski, John R.; Perez-Comas, Jose A.

2000-05-01

PIT-tags recovered from tern and cormorant breeding colonies at Rice Island and observations from the interrogation systems at John Day and Bonneville Dams were incorporated into survival analyses. Whether the estimates for the upper reaches of the system, between Lower Granite and McNary Dams were as expected (with weighted averages S{sub LGR-LGS} = 0.996, S{sub LGS-LMN} = 0.837, and S{sub LMN-McN} = 0.941), those for the lower reaches, between John Day and Bonneville Dams, appeared positively biased with survival estimates typically greater than 1. Their weighted averages were S{sub McN-JDA} = 0.707 and S{sub JDA-BON} = 1.792 for 1997 releases.more » For the 1998 releases, they were S{sub McN-JDA} = 0.795 and S{sub JDA-BON} = 1.312. If the estimates for the lower reaches were biased, the estimates for the whole project would also be biased (S{sub LGR-BON} = 0.819). We determined that bias could have arisen if the terns and cormorants of Rice Island fished for salmon yearlings in waters of the BON-Rice reach at low rates (M{sub BON-Rice} {le} 0.2), and the rates of tag-deposition and tag-detection were low (R{sub D} x R{sub R} {le} 0.4). Moreover, unknown levels of uncensored post-detection mortality and scavenging of previously dead salmon yearlings may have also added to the bias.« less

An adaptive Bayesian inference algorithm to estimate the parameters of a hazardous atmospheric release

NASA Astrophysics Data System (ADS)

Rajaona, Harizo; Septier, François; Armand, Patrick; Delignon, Yves; Olry, Christophe; Albergel, Armand; Moussafir, Jacques

2015-12-01

In the eventuality of an accidental or intentional atmospheric release, the reconstruction of the source term using measurements from a set of sensors is an important and challenging inverse problem. A rapid and accurate estimation of the source allows faster and more efficient action for first-response teams, in addition to providing better damage assessment. This paper presents a Bayesian probabilistic approach to estimate the location and the temporal emission profile of a pointwise source. The release rate is evaluated analytically by using a Gaussian assumption on its prior distribution, and is enhanced with a positivity constraint to improve the estimation. The source location is obtained by the means of an advanced iterative Monte-Carlo technique called Adaptive Multiple Importance Sampling (AMIS), which uses a recycling process at each iteration to accelerate its convergence. The proposed methodology is tested using synthetic and real concentration data in the framework of the Fusion Field Trials 2007 (FFT-07) experiment. The quality of the obtained results is comparable to those coming from the Markov Chain Monte Carlo (MCMC) algorithm, a popular Bayesian method used for source estimation. Moreover, the adaptive processing of the AMIS provides a better sampling efficiency by reusing all the generated samples.

A missing element of the deep carbon cycle: CO2 degassing estimates from rift length analysis during Pangea fragmentation

NASA Astrophysics Data System (ADS)

Brune, S.; Williams, S.; Müller, D.

2016-12-01

The deep carbon cycle connects CO2 within the atmosphere and oceans to the vast CO2 reservoir in Earth's mantle: subducted lithosphere carries CO2 into the mantle, while extensional plate boundaries and arc volcanoes release it back to Earth's surface. The length of plate boundaries thereby exerts first-order control on global CO2 fluxes on geological time scales. Here we provide a worldwide census of extensional plate boundary length from the Triassic to present day, in one million year time intervals, using a novel analysis technique (Brune et al. 2016, Nature, doi:10.1038/nature18319). The most extensive rift phase during the fragmentation of Pangea occurred in the Cretaceous with extension along the South Atlantic (9700 km) and North Atlantic rifts (9100 km), within East Gondwana (8500 km), and the failed African rift systems (4900 km). The combined extent of these and several smaller rifts amounts to more than 30.000 km of simultaneously active continental rifting. It is well-accepted that volcanoes at plate boundaries release large amounts of CO2 from the Earth's interior. Recent work, however, revealed the importance of deep-cutting faults and diffuse degassing on CO2 emissions in the East African rift (Lee et al. 2016, Nature Geoscience, doi: 10.1038/ngeo2622). Upscaling these measured CO2 fluxes to all concurrently active global rift zones, we compute first-order estimates of total rift-related CO2 degassing rates for the last 240 Myr. Our results show that rift-related CO2 release rates may have reached 600 Mt/yr in the Early Cretaceous, while Cenozoic rates rarely exceeded 200 Mt/yr. By comparison, present-day estimates of CO2 release at mid-ocean ridges range between 53 and 97 Mt/yr. We suggest that rift-related degassing during supercontinental breakup played a major role in maintaining high atmospheric CO2 concentrations through Mesozoic times, which exceeded Quaternary values by 400%.

Comparison of three nonlinear models to describe long-term tag shedding by lake trout

USGS Publications Warehouse

Fabrizio, Mary C.; Swanson, Bruce L.; Schram, Stephen T.; Hoff, Michael H.

1996-01-01

We estimated long-term tag-shedding rates for lake trout Salvelinus namaycush using two existing models and a model we developed to account for the observed permanence of some tags. Because tag design changed over the course of the study, we examined tag-shedding rates for three types of numbered anchor tags (Floy tags FD-67, FD-67C, and FD-68BC) and an unprinted anchor tag (FD-67F). Lake trout from the Gull Island Shoal region, Lake Superior, were double-tagged, and subsequent recaptures were monitored in annual surveys conducted from 1974 to 1992. We modeled tag-shedding rates, using time at liberty and probabilities of tag shedding estimated from fish released in 1974 and 1978–1983 and later recaptured. Long-term shedding of numbered anchor tags in lake trout was best described by a nonlinear model with two parameters: an instantaneous tag-shedding rate and a constant representing the proportion of tags that were never shed. Although our estimates of annual shedding rates varied with tag type (0.300 for FD-67, 0.441 for FD-67C, and 0.656 for FD-68BC), differences were not significant. About 36% of tags remained permanently affixed to the fish. Of the numbered tags that were shed (about 64%), two mechanisms contributed to tag loss: disintegration and dislodgment. Tags from about 11% of recaptured fish had disintegrated, but most tags were dislodged. Unprinted tags were shed at a significant but low rate immediately after release, but the long-term, annual shedding rate of these tags was only 0.013. Compared with unprinted tags, numbered tags dislodged at higher annual rates; we hypothesized that this was due to the greater frictional drag associated with the larger cross-sectional area of numbered tags.

Motor vehicle traffic crash fatality counts and estimates of people injured for 2007

DOT National Transportation Integrated Search

2009-02-13

This presentation supersedes the presentation released in September 2008. : The data and statements relating to fatality rates are updated based on the : latest available exposure data from the Federal Highway Administration. : Some edits were made t...

Estimating global nitrous oxide emissions by lichens and bryophytes with a process-based productivity model

NASA Astrophysics Data System (ADS)

Porada, Philipp; Pöschl, Ulrich; Kleidon, Axel; Beer, Christian; Weber, Bettina

2017-03-01

Nitrous oxide is a strong greenhouse gas and atmospheric ozone-depleting agent which is largely emitted by soils. Recently, lichens and bryophytes have also been shown to release significant amounts of nitrous oxide. This finding relies on ecosystem-scale estimates of net primary productivity of lichens and bryophytes, which are converted to nitrous oxide emissions by empirical relationships between productivity and respiration, as well as between respiration and nitrous oxide release. Here we obtain an alternative estimate of nitrous oxide emissions which is based on a global process-based non-vascular vegetation model of lichens and bryophytes. The model quantifies photosynthesis and respiration of lichens and bryophytes directly as a function of environmental conditions, such as light and temperature. Nitrous oxide emissions are then derived from simulated respiration assuming a fixed relationship between the two fluxes. This approach yields a global estimate of 0.27 (0.19-0.35) (Tg N2O) year-1 released by lichens and bryophytes. This is lower than previous estimates but corresponds to about 50 % of the atmospheric deposition of nitrous oxide into the oceans or 25 % of the atmospheric deposition on land. Uncertainty in our simulated estimate results from large variation in emission rates due to both physiological differences between species and spatial heterogeneity of climatic conditions. To constrain our predictions, combined online gas exchange measurements of respiration and nitrous oxide emissions may be helpful.

Predicting behavior and size of crown fires in the northern Rocky Mountains

Treesearch

Richard C. Rothermel

1991-01-01

Describes methods for approximating behavior and size of a wind-driven crown fire in mountainous terrain. Covers estimation of average rate of spread, energy release from tree crowns and surface fuel, fireline intensity, flame length, and unit area power of the fire and ambient wind. Plume-dominated fires, which may produce unexpectedly fast spread rates even with low...

Sediment transport and evaluation of sediment surrogate ratings in the Kootenai River near Bonners Ferry, Idaho, Water Years 2011–14

USGS Publications Warehouse

Wood, Molly S.; Fosness, Ryan L.; Etheridge, Alexandra B.

2015-12-14

Acoustic surrogate ratings were developed between backscatter data collected using acoustic Doppler velocity meters (ADVMs) and results of suspended-sediment samples. Ratings were successfully fit to various sediment size classes (total, fines, and sands) using ADVMs of different frequencies (1.5 and 3 megahertz). Surrogate ratings also were developed using variations of streamflow and seasonal explanatory variables. The streamflow surrogate ratings produced average annual sediment load estimates that were 8–32 percent higher, depending on site and sediment type, than estimates produced using the acoustic surrogate ratings. The streamflow surrogate ratings tended to overestimate suspended-sediment concentrations and loads during periods of elevated releases from Libby Dam as well as on the falling limb of the streamflow hydrograph. Estimates from the acoustic surrogate ratings more closely matched suspended-sediment sample results than did estimates from the streamflow surrogate ratings during these periods as well as for rating validation samples collected in water year 2014. Acoustic surrogate technologies are an effective means to obtain continuous, accurate estimates of suspended-sediment concentrations and loads for general monitoring and sediment-transport modeling. In the Kootenai River, continued operation of the acoustic surrogate sites and use of the acoustic surrogate ratings to calculate continuous suspended-sediment concentrations and loads will allow for tracking changes in sediment transport over time.

Evaluation of Water Year 2011 Glen Canyon Dam Flow Release Scenarios on Downstream Sand Storage along the Colorado River in Arizona

USGS Publications Warehouse

Wright, Scott A.; Grams, Paul E.

2010-01-01

This report describes numerical modeling simulations of sand transport and sand budgets for reaches of the Colorado River below Glen Canyon Dam. Two hypothetical Water Year 2011 annual release volumes were each evaluated with six hypothetical operational scenarios. The six operational scenarios include the current operation, scenarios with modifications to the monthly distribution of releases, and scenarios with modifications to daily flow fluctuations. Uncertainties in model predictions were evaluated by conducting simulations with error estimates for tributary inputs and mainstem transport rates. The modeling results illustrate the dependence of sand transport rates and sand budgets on the annual release volumes as well as the within year operating rules. The six operational scenarios were ranked with respect to the predicted annual sand budgets for Marble Canyon and eastern Grand Canyon reaches. While the actual WY 2011 annual release volume and levels of tributary inputs are unknown, the hypothetical conditions simulated and reported herein provide reasonable comparisons between the operational scenarios, in a relative sense, that may be used by decision makers within the Glen Canyon Dam Adaptive Management Program.

Field and laboratory investigations of inactivation of viruses (PRD1 and MS2) attached to iron oxide-coated quartz san

USGS Publications Warehouse

Ryan, Joseph N.; Harvey, Ronald W.; Metge, David W.; Elimelech, Menachem; Navigato, Theresa; Pieper, Ann P.

2002-01-01

Field and laboratory experiments were conducted to investigate inactivation of viruses attached to mineral surfaces. In a natural gradient transport field experiment, bacteriophage PRD1, radiolabeled with 32P, was injected into a ferric oxyhydroxide-coated sand aquifer with bromide and linear alkylbenzene sulfonates. In a zone of the aquifer contaminated by secondary sewage infiltration, small fractions of infective and 32P-labeled PRD1 broke through with the bromide tracer, followed by the slow release of 84% of the 32P activity and only 0.011% of the infective PRD1. In the laboratory experiments, the inactivation of PRD1, labeled with 35S (protein capsid), and MS2, dual radiolabeled with 35S (protein capsid) and 32P (nucleic acid), was monitored in the presence of groundwater and sediment from the contaminated zone of the field site. Release of infective viruses decreased at a much faster rate than release of the radiolabels, indicating that attached viruses were undergoing surface inactivation. Disparities between 32P and35S release suggest that the inactivated viruses were released in a disintegrated state. Comparison of estimated solution and surface inactivation rates indicates solution inactivation is ∼3 times as fast as surface inactivation. The actual rate of surface inactivation may be substantially underestimated owing to slow release of inactivated viruses.

Radiological Impact of Tritium from Gaseous Effluent Releases at Cook Nuclear Power Plant

NASA Astrophysics Data System (ADS)

Young, Joshua Allan

The purpose of this study was to investigate the washout of tritiated water by snow and rain from gaseous effluent releases at Donald C. Cook Nuclear Power Plant. Primary concepts studied were determination of washout coefficients for rainfall and snowfall; correlations between rainfall and snow fall tritium concentrations with tritium concentrations in the spent fuel pool, reactor cooling systems, and tritium release rates; and calculations of received doses from the process of recapture. The dose calculations are under the assumption of a maximally exposed individual to get the most conservative estimate of the effect that washout of tritiated water has on individuals around the plant site. This study is in addition to previous work that has been conducted at Cook Nuclear Power Plant for several years. The calculated washout coefficients were typically within the range of 1x10-7s -1 to 1x10-5s-1. A strong correlation between tritium concentration within the spent fuel pool and the tritium release rates was determined.

Effects of Iron Gate Dam discharge and other factors on the survival and migration of juvenile coho salmon in the lower Klamath River, northern California, 2006-09

USGS Publications Warehouse

Beeman, John; Juhnke, Steven; Stutzer, Greg; Wright, Katrina

2012-01-01

Current management of the Klamath River includes prescribed minimum discharges intended partly to increase survival of juvenile coho salmon during their seaward migration in the spring. To determine if fish survival was related to river discharge, we estimated apparent survival and migration rates of yearling coho salmon in the Klamath River downstream of Iron Gate Dam. The primary goals were to determine if discharge at Iron Gate Dam affected coho salmon survival and if results from hatchery fish could be used as a surrogate for the limited supply of wild fish. Fish from hatchery and wild origins that had been surgically implanted with radio transmitters were released into the Klamath River slightly downstream of Iron Gate Dam at river kilometer 309. Tagged fish were used to estimate apparent survival between, and passage rates at, a series of detection sites as far downstream as river kilometer 33. Conclusions were based primarily on data from hatchery fish, because wild fish were only available in 2 of the 4 years of study. Based on an information-theoretic approach, apparent survival of hatchery and wild fish was similar, despite differences in passage rates and timing, and was lowest in the 54 kilometer (km) reach between release and the Scott River. Models representing the hypothesis that a short-term tagging- or handling-related mortality occurred following release were moderately supported by data from wild fish and weakly supported by data from hatchery fish. Estimates of apparent survival of hatchery fish through the 276 km study area ranged from 0.412 (standard error [SE] 0.048) to 0.648 (SE 0.070), depending on the year, and represented an average of 0.790 per 100 km traveled. Estimates of apparent survival of wild fish through the study area were 0.645 (SE 0.058) in 2006 and 0.630 (SE 0.059) in 2009 and were nearly identical to the results from hatchery fish released on the same dates. The data and models examined supported positive effects of water temperature, river discharge, and fish weight as factors affecting apparent survival in the Klamath River upstream of the confluence with the Shasta River, but few of the variables examined were supported as factors affecting survival farther downstream. The effect of water temperature on apparent survival upstream of the Shasta River was greater than Iron Gate Dam discharge, which was greater than fish weight. The estimated effect on apparent survival between release and the Shasta River with each 1degree Celsius increase in water temperature was 1.4 times the effect of a 100 cubic feet per second increase in Iron Gate Dam discharge and 2.5 times the effect of a 1 gram increase in fish weight, and the effects of discharge and weight diminished at higher water temperatures up to the 17.91 degrees Celsius maximum present in the data examined. The rate of passage at the detection site near the confluence with the Shasta River was primarily affected by date of release, and water temperature was the only factor supported at the site near the confluence with the Scott River. Passage rates at sites downstream of the Scott River were affected by several of the variables examined, but the estimated effects were small and often imprecise. Results from this study indicate that discharge at Iron Gate Dam has a positive effect on apparent survival of yearling coho salmon in the Klamath River upstream of the Shasta River, but the effects are smaller than those of water temperature and are mediated by it. The results also support the use of hatchery fish as surrogates for wild fish in studies of apparent survival, but the available evidence suggests that study fish should be released well upstream of the area of interest, due to short-term differences in survival and migration behavior of hatchery and wild fish after release.

Estimating Global “Blue Carbon” Emissions from Conversion and Degradation of Vegetated Coastal Ecosystems

PubMed Central

Murray, Brian C.; Crooks, Stephen; Jenkins, W. Aaron; Sifleet, Samantha; Craft, Christopher; Fourqurean, James W.; Kauffman, J. Boone; Marbà, Núria; Megonigal, Patrick; Pidgeon, Emily; Herr, Dorothee; Gordon, David; Baldera, Alexis

2012-01-01

Recent attention has focused on the high rates of annual carbon sequestration in vegetated coastal ecosystems—marshes, mangroves, and seagrasses—that may be lost with habitat destruction (‘conversion’). Relatively unappreciated, however, is that conversion of these coastal ecosystems also impacts very large pools of previously-sequestered carbon. Residing mostly in sediments, this ‘blue carbon’ can be released to the atmosphere when these ecosystems are converted or degraded. Here we provide the first global estimates of this impact and evaluate its economic implications. Combining the best available data on global area, land-use conversion rates, and near-surface carbon stocks in each of the three ecosystems, using an uncertainty-propagation approach, we estimate that 0.15–1.02 Pg (billion tons) of carbon dioxide are being released annually, several times higher than previous estimates that account only for lost sequestration. These emissions are equivalent to 3–19% of those from deforestation globally, and result in economic damages of $US 6–42 billion annually. The largest sources of uncertainty in these estimates stems from limited certitude in global area and rates of land-use conversion, but research is also needed on the fates of ecosystem carbon upon conversion. Currently, carbon emissions from the conversion of vegetated coastal ecosystems are not included in emissions accounting or carbon market protocols, but this analysis suggests they may be disproportionally important to both. Although the relevant science supporting these initial estimates will need to be refined in coming years, it is clear that policies encouraging the sustainable management of coastal ecosystems could significantly reduce carbon emissions from the land-use sector, in addition to sustaining the well-recognized ecosystem services of coastal habitats. PMID:22962585

Estimating global "blue carbon" emissions from conversion and degradation of vegetated coastal ecosystems.

PubMed

Pendleton, Linwood; Donato, Daniel C; Murray, Brian C; Crooks, Stephen; Jenkins, W Aaron; Sifleet, Samantha; Craft, Christopher; Fourqurean, James W; Kauffman, J Boone; Marbà, Núria; Megonigal, Patrick; Pidgeon, Emily; Herr, Dorothee; Gordon, David; Baldera, Alexis

2012-01-01

Recent attention has focused on the high rates of annual carbon sequestration in vegetated coastal ecosystems--marshes, mangroves, and seagrasses--that may be lost with habitat destruction ('conversion'). Relatively unappreciated, however, is that conversion of these coastal ecosystems also impacts very large pools of previously-sequestered carbon. Residing mostly in sediments, this 'blue carbon' can be released to the atmosphere when these ecosystems are converted or degraded. Here we provide the first global estimates of this impact and evaluate its economic implications. Combining the best available data on global area, land-use conversion rates, and near-surface carbon stocks in each of the three ecosystems, using an uncertainty-propagation approach, we estimate that 0.15-1.02 Pg (billion tons) of carbon dioxide are being released annually, several times higher than previous estimates that account only for lost sequestration. These emissions are equivalent to 3-19% of those from deforestation globally, and result in economic damages of $US 6-42 billion annually. The largest sources of uncertainty in these estimates stems from limited certitude in global area and rates of land-use conversion, but research is also needed on the fates of ecosystem carbon upon conversion. Currently, carbon emissions from the conversion of vegetated coastal ecosystems are not included in emissions accounting or carbon market protocols, but this analysis suggests they may be disproportionally important to both. Although the relevant science supporting these initial estimates will need to be refined in coming years, it is clear that policies encouraging the sustainable management of coastal ecosystems could significantly reduce carbon emissions from the land-use sector, in addition to sustaining the well-recognized ecosystem services of coastal habitats.

Concentration-effect relationship of levodopa in patients with Parkinson's disease after oral administration of an immediate release and a controlled release formulation.

PubMed Central

Harder, S; Baas, H; Bergemann, N; Demisch, L; Rietbrock, S

1995-01-01

1. The relationship between plasma concentration of levodopa and motor-response was investigated in 12 patients with Parkinson's disease who showed marked response fluctuations, after a single oral dose of an immediate release (IR) formulation (100 mg levodopa/25 mg genserazide) and a controlled release (CR) formulation (300 mg levodopa/75 mg benserazide), using a double-blind, randomized, cross-over design. 2. The sum score of the Columbia University Rating Scale (CURS sigma) was used for pharmacodynamic assessment. A sigmoidal Emax-model was fitted to the data using a semiparametric pharmacokinetic/dynamic approach. 3. The dose-corrected AUC of levodopa after the IR-formulation was 27.5 (+/- 9.1 s.d.) ng ml-1 h per mg and 23.2 (+/- 4.6 s.d.) ng ml-1 h per mg after the CR-formulation. Cmax was 1714 (+/- 1027 s.d.) ng ml-1 after the IR-formulation and 1494 (+/- 383 s.d.) ng ml-1 after the CR-formulation. 4. With both preparations, the maximal response to levodopa (Emax) was a decrease in the CURS sigma rating of about 27 scores. Estimates of the EC50 of levodopa were 495 (+/- 144 s.d.) ng ml-1 (IR) and 1024 (+/- 502 s.d.) ng ml-1 (CR), respectively (95%-CI: 1.51-2.66, point estimator 1.95). The mean duration of the motor response was 1.9 (+/- 0.5 s.d.) h (IR) and 2.8 (+/- 0.7 s.d.) h (CR), respectively (95%-CI: 1.12-2.04, point estimator 1.53).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7756097

The hydrology of northern peatlands as affected by biogenic gas: Current developments and research needs

USGS Publications Warehouse

Rosenberry, D.O.; Glaser, P.H.; Siegel, D.I.

2006-01-01

Recent research indicates that accumulation and release of biogenic gas from northern peatlands may substantially affect future climate. Sudden release of free-phase gas bubbles into the atmosphere may preclude the conversion of methane to carbon dioxide in the uppermost oxic layer of the peat, resulting in greater contribution of methane to the atmosphere than is currently estimated. The hydrology of these peatlands also affects and is affected by this process, especially when gas is released suddenly and episodically. Indirect hydrological evidence indicates that ebullitive gas releases are relatively frequent in some peatlands and time-averaged rates may be significantly greater than diffusive releases. Estimates of free-phase gas contained in peat have ranged from 0 to nearly 20% of the peat volume. Abrupt changes in the volume of gas may alter hydraulic gradients and movement of water and solutes in peat, which in turn could alter composition and fluxes of the gas. Peat surfaces also move vertically and horizontally in response to accumulation and release of free-phase gas. Future research should address the distribution, temporal variability, and relative significance of ebullition in peatlands and the consequent hydrological responses to these gas-emission events. Copyright ?? 2006 John Wiley & Sons, Ltd.

Epidemiology of Infectious Disease–Related Death After Release from Prison, Washington State, United States, and Queensland, Australia: A Cohort Study

PubMed Central

Blatchford, Patrick J.; Forsyth, Simon J.; Stern, Marc F.; Kinner, Stuart A.

2016-01-01

Objectives People in prison may be at high risk for infectious diseases and have an elevated risk of death immediately after release compared with later; their risk of death is elevated for at least a decade after release. We compared rates, characteristics, and prison-related risk factors for infectious disease–related mortality among people released from prisons in Queensland, Australia, and Washington State, United States, regions with analogous available data. Methods We analyzed data from retrospective cohort studies of people released from prison in Queensland (1997–2007, n=37,180) and Washington State (1999–2009, n=76,208) and linked identifiers from each cohort to its respective national death index. We estimated infectious disease–related mortality rates (deaths per person-years in community) and examined associations using Cox proportional hazard models. Results The most frequent infectious disease–related underlying cause of death after release from prison was pneumonia (43%, 23/54 deaths) in the Australian cohort and viral hepatitis (40%, 69/171 deaths) in the U.S. cohort. The infectious disease–related mortality rate was significantly higher in the U.S. cohort than in the Australian cohort (51.2 vs. 26.5 deaths per 100,000 person-years; incidence rate ratio = 1.93, 95% confidence interval 1.42, 2.62). In both cohorts, increasing age was strongly associated with mortality from infectious diseases. Conclusion Differences in the epidemiology of infectious disease–related mortality among people released from prison may reflect differences in patterns of community health service delivery in each region. These findings highlight the importance of preventing and treating hepatitis C and other infectious diseases during the transition from prison to the community. PMID:27453602

Epidemiology of Infectious Disease-Related Death After Release from Prison, Washington State, United States, and Queensland, Australia: A Cohort Study.

PubMed

Binswanger, Ingrid A; Blatchford, Patrick J; Forsyth, Simon J; Stern, Marc F; Kinner, Stuart A

2016-01-01

People in prison may be at high risk for infectious diseases and have an elevated risk of death immediately after release compared with later; their risk of death is elevated for at least a decade after release. We compared rates, characteristics, and prison-related risk factors for infectious disease-related mortality among people released from prisons in Queensland, Australia, and Washington State, United States, regions with analogous available data. We analyzed data from retrospective cohort studies of people released from prison in Queensland (1997-2007, n=37,180) and Washington State (1999-2009, n=76,208) and linked identifiers from each cohort to its respective national death index. We estimated infectious disease-related mortality rates (deaths per person-years in community) and examined associations using Cox proportional hazard models. The most frequent infectious disease-related underlying cause of death after release from prison was pneumonia (43%, 23/54 deaths) in the Australian cohort and viral hepatitis (40%, 69/171 deaths) in the U.S. cohort. The infectious disease-related mortality rate was significantly higher in the U.S. cohort than in the Australian cohort (51.2 vs. 26.5 deaths per 100,000 person-years; incidence rate ratio = 1.93, 95% confidence interval 1.42, 2.62). In both cohorts, increasing age was strongly associated with mortality from infectious diseases. Differences in the epidemiology of infectious disease-related mortality among people released from prison may reflect differences in patterns of community health service delivery in each region. These findings highlight the importance of preventing and treating hepatitis C and other infectious diseases during the transition from prison to the community.

Oxygen toxicity in the perfused rat liver and lung under hyperbaric conditions.

PubMed Central

Nishiki, K; Jamieson, D; Oshino, N; Chance, B

1976-01-01

1. In the lung and liver of tocopherol-deficient rats, the activities of glutathione peroxidase and glucose 6-phosphate dehydrogenase were increased substantially, suggesting an important role for both enzymes in protecting the organ against the deleterious effects of lipid peroxides. 2. Facilitation of the glutathione peroxidase reaction by infusing t-butyl hydroperoxide caused the oxidation of nicotinamide nucleotides and glutathione, resulting in a concomitant increase in the rate of release of oxidized glutathione into the perfusate. Thus the rate of production of lipid peroxide and H2O2 in the perfused organ could be compared by simultaneous measurement of the rate of glutathione release and the turnover number of the catalase reaction. 3. On hyperbaric oxygenation at 4 X 10(5)Pa, H2O2 production, estimated from the turnover of the catalase reaction, was increased slightly in the liver, and glutathione release was increased slightly, in both lung and liver. 4. Tocopherol deficiency caused a marked increase in lipid-peroxide formation as indicated by a corresponding increase in glutathione release under hyperbaric oxygenation, with a further enhancement when the tocopherol-deficient rats were also starved. 5. The study demonstrates that the primary response to hyperbaric oxygenation is an elevation of the rate of lipid peroxidation rather than of the rate of formation of H2O2 or superoxide. PMID:12754

Effect of composition in the development of carbamazepine hot-melt extruded solid dispersions by application of mixture experimental design.

PubMed

Djuris, Jelena; Ioannis, Nikolakakis; Ibric, Svetlana; Djuric, Zorica; Kachrimanis, Kyriakos

2014-02-01

This study investigates the application of hot-melt extrusion for the formulation of carbamazepine (CBZ) solid dispersions, using polyethyleneglycol-polyvinyl caprolactam-polyvinyl acetate grafted copolymer (Soluplus, BASF, Germany) and polyoxyethylene-polyoxypropylene block copolymer (Poloxamer 407). In agreement with the current Quality by Design principle, formulations of solid dispersions were prepared according to a D-optimal mixture experimental design, and the influence of formulation composition on the properties of the dispersions (CBZ heat of fusion and release rate) was estimated. Prepared solid dispersions were characterized using differential scanning calorimetry, attenuated total reflectance infrared spectroscopy and hot stage microscopy, as well as by determination of the dissolution rate of CBZ from the hot-melt extrudates. Solid dispersions of CBZ can be successfully prepared using the novel copolymer Soluplus. Inclusion of Poloxamer 407 as a plasticizer facilitated the processing and decreased the hardness of hot-melt extrudates. Regardless of their composition, all hot-melt extrudates displayed an improvement in the release rate compared to the pure CBZ, with formulations having the ratio of CBZ : Poloxamer 407 = 1 : 1 showing the highest increase in CBZ release rate. Interactions between the mixture components (CBZ and polymers), or quadratic effects of the components, play a significant role in overall influence on the CBZ release rate. © 2013 Royal Pharmaceutical Society.

Tobacco imagery in Bollywood films: 2006–2008

PubMed Central

Nazar, Gaurang P; Gupta, Vinay K; Millett, Christopher; Arora, Monika

2013-01-01

Objective To estimate exposure to tobacco imagery in youth-rated Bollywood films, and examine the results in light of recent developments in India's film rating system. Methods Content coding of 44 top grossing Bollywood films (including 38 youth-rated films) released during 2006–2008 was undertaken to estimate tobacco occurrences and impressions. Results Out of the 38 youth-rated (U and U/A) films coded, 50% contained tobacco imagery. Mean tobacco occurrences were 1.9, 2.9 and 13.7 per U, U/A and adult (A) rated films, respectively. Top grossing youth-rated films delivered 1.91 billion tobacco impressions to Indian cinema audiences. Conclusions Half the youth-rated Bollywood films contain tobacco imagery resulting in large population level exposure in India, relative to other countries. Measures to reduce youth exposure to tobacco imagery through films, such as restricting access through the rating system, will complement other tobacco control measures. PMID:27326073

Snake River Sockeye Salmon Captive Broodstock Program Research Elements : 2007 Annual Project Progess Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, Mike; Plaster, Kurtis; Redfield, Laura

2008-12-17

On November 20, 1991, the National Oceanic Atmospheric Administration listed Snake River sockeye salmon Oncorhynchus nerka as endangered under the Endangered Species Act of 1973. In 1991, the Shoshone-Bannock Tribes (SBT) and Idaho Department of Fish and Game (IDFG) initiated the Snake River Sockeye Salmon Captive Broodstock Program to conserve and rebuild populations in Idaho. Restoration efforts are focused on Redfish, Pettit, and Alturas lakes within the Sawtooth Valley. The first release of hatchery-produced adults occurred in 1993. The first release of juvenile sockeye salmon from the captive broodstock program occurred in 1994. In 1999, the first anadromous adult returnsmore » from the captive broodstock program were recorded when six jacks and one jill were captured at the IDFG Sawtooth Fish Hatchery. In 2007, progeny from the captive broodstock program were released using four strategies: (1) eyed-eggs were planted in Pettit Lake in November; (2) age-0 presmolts were released to Alturas, Pettit, and Redfish lakes in October; (3) age-1 smolts were released into Redfish Lake Creek and the upper Salmon River in May; and (4) hatchery-produced adult sockeye salmon were released to Redfish Lake for volitional spawning in September. Oncorhynchus nerka population monitoring was conducted on Redfish, Alturas, and Pettit lakes using a midwater trawl in September 2007. Population abundances were estimated at 73,702 fish for Redfish Lake, 124,073 fish for Alturas Lake, and 14,746 fish for Pettit Lake. Angler surveys were conducted from May 26 through August 7, 2007 on Redfish Lake to estimate kokanee harvest. On Redfish Lake, we interviewed 102 anglers and estimated that 56 kokanee were harvested. The calculated kokanee catch rate was 0.03 fish/hour for each kokanee kept. The juvenile out-migrant trap on Redfish Lake Creek was operated from April 14 to June 13, 2007. We estimated that 5,280 natural origin and 14,256 hatchery origin sockeye salmon smolts out-migrated from Redfish Lake in 2007. The hatchery origin component originated from a 2006 fall presmolt direct-release. The juvenile out-migrant traps on Alturas Lake Creek and Pettit Lake Creek were operated by the SBT from April 19 to May 23, 2007 and April 18 to May 29, 2007, respectively. The SBT estimated 1,749 natural origin and 4,695 hatchery origin sockeye salmon smolts out-migrated from Pettit Lake and estimated 8,994 natural origin and 6,897 hatchery origin sockeye salmon smolts out-migrated from Alturas Lake in 2007. The hatchery origin component of sockeye salmon out-migrants originated from fall presmolt direct-releases made to Pettit and Alturas lakes in 2006. In 2007, the Stanley Basin Sockeye Technical Oversight Committee (SBSTOC) chose to have all Snake River sockeye salmon juveniles (tagged and untagged) transported due to potential enhanced survival. Therefore, mainstem survival evaluations were only conducted to Lower Granite Dam. Unique PIT tag interrogations from Sawtooth Valley juvenile out-migrant traps to Lower Granite Dam were utilized to estimate survival rates for out-migrating sockeye salmon smolts. Survival rate comparisons were made between smolts originating from Redfish, Alturas, and Pettit lakes and the various release strategies. Alturas Lake hatchery origin smolts tagged at the out-migrant trap recorded the highest survival rate of 78.0%. In 2007, 494 hatchery origin adult sockeye salmon were released to Redfish Lake for natural spawning. We observed 195 areas of excavation in the lake from spawning events. This was the highest number of redds observed in Redfish Lake since the program was initiated. Suspected redds were approximately 3 m x 3 m in size and were constructed by multiple pairs of adults. To monitor the predator population found within the lakes, we monitored bull trout spawning in Fishhook Creek, a tributary to Redfish Lake; and in Alpine Creek, a tributary to Alturas Lake. This represented the tenth consecutive year that the index reaches have been surveyed on these two streams. Adult counts (41 adults) and redd counts (22 redds) in Fishhook Creek increased compared to counts conducted since monitoring began in 1998. Beginning in 2007, we also surveyed an additional trend site in Fishhook Creek resulting in observing 43 adult bull trout and 30 additional redds. Bull trout numbers (13 adults) and the number of redds observed (18 redds) have gradually increased in Alpine Creek compared to counts from initial monitoring.« less

[The release of biologically active compounds from peat peloids].

PubMed

Babaskin, D V

2011-01-01

This work had the objective to study kinetics of the release of flavonoides from peat peloid compositions containing extracts of medicinal herbs in model systems.The key parameters of the process are defined. The rate of liberation of flavonoides is shown to depend on their initial concentration in the compositions being used. The influence of the flavonoide composition of the tested extracts and dimethylsulfoxide on the release of biologically active compounds contained in the starting material in the model environment is estimated. The possibility of the layer-by-layer deposition of the compositions and peat peloids in order to increase the efficacy of flavonoide release from the starting composition and to ensure more rational utilization of the extracts of medicinal plants is demonstrated.

Strain Anomalies during an Earthquake Sequence in the South Iceland Seismic Zone

NASA Astrophysics Data System (ADS)

Arnadottir, T.; Haines, A. J.; Geirsson, H.; Hreinsdottir, S.

2017-12-01

The South Iceland Seismic Zone (SISZ) accommodates E-W translation due to oblique spreading between the North American/Hreppar microplate and Eurasian plate, in South Iceland. Strain is released in the SISZ during earthquake sequences that last days to years, at average intervals of 80-100 years. The SISZ is currently in the midst of an earthquake sequence that started with two M6.5 earthquakes in June 2000, and continued with two M6 earthquakes in May 2008. Estimates of geometric strain accumulation, and seismic strain release in these events indicate that they released at most only half of the strain accumulated since the last earthquake cycle in 1896-1912. Annual GPS campaigns and continuous measurements during 2001-2015 were used to calculate station velocities and strain rates from a new method using the vertical derivatives of horizontal stress (VDoHS). This new method allows higher resolution of strain rates than other (older) approaches, as the strain rates are estimated by integrating VDoHS rates obtained by inversion rather than differentiating interpolated GPS velocities. Estimating the strain rates for eight 1-2 year intervals indicates temporal and spatial variation of strain rates in the SISZ. In addition to earthquake faulting, the strain rates in the SISZ are influenced by anthropogenic signals due to geothermal exploitation, and magma movements in neighboring volcanoes - Hekla and Eyjafjallajökull. Subtle signals of post-seismic strain rate changes are seen following the June 2000 M6.5 main shocks, but interestingly, much larger strain rate variations are observed after the two May 2008 M6 main shocks. A prominent strain anomaly is evident in the epicentral area prior to the May 2008 earthquake sequence. The strain signal persists over at least 4 years in the epicentral area, leading up to the M6 main shocks. The strain is primarily extension in ESE-WNW direction (sub-parallel to the direction of plate spreading), but overall shear across the N-S faults that subsequently ruptured, increases with time. The pre-2008 strain anomaly and large post-2008 strain variations are enigmatic, but may signify crustal fluids and/or differences in rheology and crustal thickness between the 2000 and 2008 epicentral areas.

Resolving the Origin of Rabbit Hemorrhagic Disease Virus: Insights from an Investigation of the Viral Stocks Released in Australia

PubMed Central

Eden, John-Sebastian; Read, Andrew J.; Duckworth, Janine A.; Strive, Tanja

2015-01-01

To resolve the evolutionary history of rabbit hemorrhagic disease virus (RHDV), we performed a genomic analysis of the viral stocks imported and released as a biocontrol measure in Australia, as well as a global phylogenetic analysis. Importantly, conflicts were identified between the sequences determined here and those previously published that may have affected evolutionary rate estimates. By removing likely erroneous sequences, we show that RHDV emerged only shortly before its initial description in China. PMID:26378178

Effect of drug lipophilicity on in vitro release rate from oil vehicles using nicotinic acid esters as model prodrug derivatives.

PubMed

Weng Larsen, S; Engelbrecht Thomsen, A E; Rinvar, E; Friis, G J; Larsen, C

2001-03-23

The rate constants for transfer of a homologous series of nicotinic acid esters from oil vehicles to aqueous buffer phases were determined using a rotating dialysis cell. The chemical stability of butyl nicotinate has been investigated at 60 degrees C over pH range 0.5--10. Maximum stability occurs at pH 4--5 and an inflection point was seen around the pK(a). For the nicotinic acid esters, a linear correlation was established between the first-order rate constant related to attainment of equilibrium, k(obs) and the apparent partition coefficient, P(app): log k(obs)=-0.83log P(app)+0.26 (k(obs) in h(-1), n=9). For hexyl nicotinate with a true partition coefficient of 4 it was possible to determine k(obs) by decreasing pH in the aqueous release medium to 2.05. Thus, under the latter experimental conditions estimation of the relative release rates for the esters were performed. The ratio between the specific rate constant k(ow), related to the transport from oil vehicle to aqueous phase, for ethyl and hexyl nicotinate was 139. The hydrophobic substituent constant for a methylene group, pi(CH(2)), was determined for nicotinic acid esters in different oil/buffer partitioning systems to 0.54--0.58. Addition of hydroxypropyl-beta-cyclodextrin to the aqueous release medium did not enhance the transport rate of the esters from the oil phase.

Ecological impacts of the Deepwater Horizon oil spill: implications for immunotoxicity

EPA Science Inventory

Summary of major Federal and multi-stake holder research efforts in response to the DWH spill, including laboratory oil dispersant testing, estimation of oil release rates and oil fate calculations, subsea monitoring, and post-spill assessments. Impacts from shoreline oiling, wil...

Combining tracer flux ratio methodology with low-flying aircraft measurements to estimate dairy farm CH4 emissions

NASA Astrophysics Data System (ADS)

Daube, C.; Conley, S.; Faloona, I. C.; Yacovitch, T. I.; Roscioli, J. R.; Morris, M.; Curry, J.; Arndt, C.; Herndon, S. C.

2017-12-01

Livestock activity, enteric fermentation of feed and anaerobic digestion of waste, contributes significantly to the methane budget of the United States (EPA, 2016). Studies question the reported magnitude of these methane sources (Miller et. al., 2013), calling for more detailed research of agricultural animals (Hristov, 2014). Tracer flux ratio is an attractive experimental method to bring to this problem because it does not rely on estimates of atmospheric dispersion. Collection of data occurred during one week at two dairy farms in central California (June, 2016). Each farm varied in size, layout, head count, and general operation. The tracer flux ratio method involves releasing ethane on-site with a known flow rate to serve as a tracer gas. Downwind mixed enhancements in ethane (from the tracer) and methane (from the dairy) were measured, and their ratio used to infer the unknown methane emission rate from the farm. An instrumented van drove transects downwind of each farm on public roads while tracer gases were released on-site, employing the tracer flux ratio methodology to assess simultaneous methane and tracer gas plumes. Flying circles around each farm, a small instrumented aircraft made measurements to perform a mass balance evaluation of methane gas. In the course of these two different methane quantification techniques, we were able to validate yet a third method: tracer flux ratio measured via aircraft. Ground-based tracer release rates were applied to the aircraft-observed methane-to-ethane ratios, yielding whole-site methane emission rates. Never before has the tracer flux ratio method been executed with aircraft measurements. Estimates from this new application closely resemble results from the standard ground-based technique to within their respective uncertainties. Incorporating this new dimension to the tracer flux ratio methodology provides additional context for local plume dynamics and validation of both ground and flight-based data.

A primary estimate of global PCDD/F release based on the quantity and quality of national economic and social activities.

PubMed

Wang, Bin; Fiedler, Heidelore; Huang, Jun; Deng, Shubo; Wang, Yujue; Yu, Gang

2016-05-01

The correlations between polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) releases and factors relevant to human social-economic activities (HSEAs) were analyzed. The multiple linear regression model was successfully developed to estimate the total global PCDD/F release. The PCDD/F releases significantly correlated with population, area, GDP and GNI, suggesting that "quantity" of HSEAs have significantly contributed to the PCDD/F releases. On another aspect, advanced technologies are usually adopted in developed countries/regions, and hence reduce the PCDD/F release. The significant correlation between PCDD/F release and CO2 emission implies the potential of simultaneous reduction of CO2 emission and PCDD/F release. The total global PCDD/F release from 196 countries/regions was estimated to be 100.4 kg-TEQ yr(-1). The estimated annual PCDD/F release per unit area ranged from 0.007 to 28 mg-TEQ km(-2). Asia is estimated to have the highest PCDD/F release of 47.1 kg-TEQ yr(-1), almost half of the total world release. Oceania is estimated to have the smallest total release but the largest per-capita release. For the developed areas, such as Europe and North America, the PCDD/F release per unit GDP is lower, while for Africa, it is much higher. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modified ensemble Kalman filter for nuclear accident atmospheric dispersion: prediction improved and source estimated.

PubMed

Zhang, X L; Su, G F; Yuan, H Y; Chen, J G; Huang, Q Y

2014-09-15

Atmospheric dispersion models play an important role in nuclear power plant accident management. A reliable estimation of radioactive material distribution in short range (about 50 km) is in urgent need for population sheltering and evacuation planning. However, the meteorological data and the source term which greatly influence the accuracy of the atmospheric dispersion models are usually poorly known at the early phase of the emergency. In this study, a modified ensemble Kalman filter data assimilation method in conjunction with a Lagrangian puff-model is proposed to simultaneously improve the model prediction and reconstruct the source terms for short range atmospheric dispersion using the off-site environmental monitoring data. Four main uncertainty parameters are considered: source release rate, plume rise height, wind speed and wind direction. Twin experiments show that the method effectively improves the predicted concentration distribution, and the temporal profiles of source release rate and plume rise height are also successfully reconstructed. Moreover, the time lag in the response of ensemble Kalman filter is shortened. The method proposed here can be a useful tool not only in the nuclear power plant accident emergency management but also in other similar situation where hazardous material is released into the atmosphere. Copyright © 2014 Elsevier B.V. All rights reserved.

A Monte Carlo program to calculate the exposure rate from airborne radioactive gases inside a nuclear reactor containment building.

PubMed

Sherbini, S; Tamasanis, D; Sykes, J; Porter, S W

1986-12-01

A program was developed to calculate the exposure rate resulting from airborne gases inside a reactor containment building. The calculations were performed at the location of a wall-mounted area radiation monitor. The program uses Monte Carlo techniques and accounts for both the direct and scattered components of the radiation field at the detector. The scattered component was found to contribute about 30% of the total exposure rate at 50 keV and dropped to about 7% at 2000 keV. The results of the calculations were normalized to unit activity per unit volume of air in the containment. This allows the exposure rate readings of the area monitor to be used to estimate the airborne activity in containment in the early phases of an accident. Such estimates, coupled with containment leak rates, provide a method to obtain a release rate for use in offsite dose projection calculations.

Slip rates and spatially variable creep on faults of the northern San Andreas system inferred through Bayesian inversion of Global Positioning System data

USGS Publications Warehouse

Murray, Jessica R.; Minson, Sarah E.; Svarc, Jerry L.

2014-01-01

Fault creep, depending on its rate and spatial extent, is thought to reduce earthquake hazard by releasing tectonic strain aseismically. We use Bayesian inversion and a newly expanded GPS data set to infer the deep slip rates below assigned locking depths on the San Andreas, Maacama, and Bartlett Springs Faults of Northern California and, for the latter two, the spatially variable interseismic creep rate above the locking depth. We estimate deep slip rates of 21.5 ± 0.5, 13.1 ± 0.8, and 7.5 ± 0.7 mm/yr below 16 km, 9 km, and 13 km on the San Andreas, Maacama, and Bartlett Springs Faults, respectively. We infer that on average the Bartlett Springs fault creeps from the Earth's surface to 13 km depth, and below 5 km the creep rate approaches the deep slip rate. This implies that microseismicity may extend below the locking depth; however, we cannot rule out the presence of locked patches in the seismogenic zone that could generate moderate earthquakes. Our estimated Maacama creep rate, while comparable to the inferred deep slip rate at the Earth's surface, decreases with depth, implying a slip deficit exists. The Maacama deep slip rate estimate, 13.1 mm/yr, exceeds long-term geologic slip rate estimates, perhaps due to distributed off-fault strain or the presence of multiple active fault strands. While our creep rate estimates are relatively insensitive to choice of model locking depth, insufficient independent information regarding locking depths is a source of epistemic uncertainty that impacts deep slip rate estimates.

OrganoRelease - A framework for modeling the release of organic chemicals from the use and post-use of consumer products.

PubMed

Tao, Mengya; Li, Dingsheng; Song, Runsheng; Suh, Sangwon; Keller, Arturo A

2018-03-01

Chemicals in consumer products have become the focus of recent regulatory developments including California's Safer Consumer Products Act. However, quantifying the amount of chemicals released during the use and post-use phases of consumer products is challenging, limiting the ability to understand their impacts. Here we present a comprehensive framework, OrganoRelease, for estimating the release of organic chemicals from the use and post-use of consumer products given limited information. First, a novel Chemical Functional Use Classifier estimates functional uses based on chemical structure. Second, the quantity of chemicals entering different product streams is estimated based on market share data of the chemical functional uses. Third, chemical releases are estimated based on either chemical product categories or functional uses by using the Specific Environmental Release Categories and EU Technological Guidance Documents. OrganoRelease connects 19 unique functional uses and 14 product categories across 4 data sources and provides multiple pathways for chemical release estimation. Available user information can be incorporated in the framework at various stages. The Chemical Functional Use Classifier achieved an average accuracy above 84% for nine functional uses, which enables the OrganoRelease to provide release estimates for the chemical, mostly using only the molecular structure. The results can be can be used as input for methods estimating environmental fate and exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Risk Associated with the Release of Wolbachia-Infected Aedes aegypti Mosquitoes into the Environment in an Effort to Control Dengue.

PubMed

Murray, Justine V; Jansen, Cassie C; De Barro, Paul

2016-01-01

In an effort to eliminate dengue, a successful technology was developed with the stable introduction of the obligate intracellular bacteria Wolbachia pipientis into the mosquito Aedes aegypti to reduce its ability to transmit dengue fever due to life shortening and inhibition of viral replication effects. An analysis of risk was required before considering release of the modified mosquito into the environment. Expert knowledge and a risk assessment framework were used to identify risk associated with the release of the modified mosquito. Individual and group expert elicitation was performed to identify potential hazards. A Bayesian network (BN) was developed to capture the relationship between hazards and the likelihood of events occurring. Risk was calculated from the expert likelihood estimates populating the BN and the consequence estimates elicited from experts. The risk model for "Don't Achieve Release" provided an estimated 46% likelihood that the release would not occur by a nominated time but generated an overall risk rating of very low. The ability to obtain compliance had the greatest influence on the likelihood of release occurring. The risk model for "Cause More Harm" provided a 12.5% likelihood that more harm would result from the release, but the overall risk was considered negligible. The efficacy of mosquito management had the most influence, with the perception that the threat of dengue fever had been eliminated, resulting in less household mosquito control, and was scored as the highest ranked individual hazard (albeit low risk). The risk analysis was designed to incorporate the interacting complexity of hazards that may affect the release of the technology into the environment. The risk analysis was a small, but important, implementation phase in the success of this innovative research introducing a new technology to combat dengue transmission in the environment.

Controlled release of tocopherols from polymer blend films

NASA Astrophysics Data System (ADS)

Obinata, Noe

Controlled release packaging has great potential to increase storage stability of foods by releasing active compounds into foods continuously over time. However, a major limitation in development of this technology is the inability to control the release and provide rates useful for long term storage of foods. Better understanding of the factors affecting active compound release is needed to overcome this limitation. The objective of this research was to investigate the relationship between polymer composition, polymer processing method, polymer morphology, and release properties of active compounds, and to provide proof of principle that compound release is controlled by film morphology. A natural antioxidant, tocopherol was used as a model active compound because it is natural, effective, heat stable, and soluble in most packaging polymers. Polymer blend films were produced from combination of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE), polypropylene (PP), or polystyrene (PS) with 3000 ppm mixed tocopherols using conventional blending method and innovative blending method, smart blending with a novel mixer using chaotic advection. Film morphologies were visualized with scanning electron microscopy (SEM). Release of tocopherols into 95% ethanol as a food simulant was measured by UV/Visible spectrophotometry or HPLC, and diffusivity of tocopherols in the polymers was estimated from this data. Polymer composition (blend proportions) and processing methods have major effects on film morphology. Four different types of morphologies, dispersed, co-continuous, fiber, and multilayer structures were developed by either conventional extrusion or smart blending. With smart blending of fixed polymer compositions, different morphologies were progressively developed with fixed polymer composition as the number of rod rotations increased, providing a way to separate effects of polymer composition and morphology. The different morphologies obtained using conventional and smart blending greatly affected tocopherol release. Strong correlation was observed between morphology and release rate: multilayer, slow release; co-continuous and fiber, moderate; disperse: fast release. Results indicate that morphology can be manipulated by polymer composition and processing method, and release rates of tocopherols are varied with polymer morphology. Manipulating polymer compositions and film morphologies may provide a means to control the release of tocopherols from food contact films.

Calcium release and its voltage dependence in frog cut muscle fibers equilibrated with 20 mM EGTA

PubMed Central

1995-01-01

Sarcoplasmic reticulum (SR) Ca release was studied at 13-16 degrees C in cut fibers (sarcomere length, 3.4-3.9 microns) mounted in a double Vaseline-gap chamber. The amplitude and duration of the action- potential stimulated free [Ca] transient were reduced by equilibration with end-pool solutions that contained 20 mM EGTA with 1.76 mM Ca and 0.63 mM phenol red, a maneuver that appeared to markedly reduce the amount of Ca complexed by troponin. A theoretical analysis shows that, under these conditions, the increase in myoplasmic free [Ca] is expected to be restricted to within a few hundred nanometers of the SR Ca release sites and to have a time course that essentially matches that of release. Furthermore, almost all of the Ca that is released from the SR is expected to be rapidly bound by EGTA and exchanged for protons with a 1:2 stoichiometry. Consequently, the time course of SR Ca release can be estimated by scaling the delta pH signal measured with phenol red by -beta/2. The value of beta, the buffering power of myoplasm, was determined in fibers equilibrated with a combination of EGTA, phenol red, and fura-2; its mean value was 22 mM/pH unit. The Ca content of the SR (expressed as myoplasmic concentration) was estimated from the total amount of Ca released by either a train of action potentials or a depleting voltage step; its mean value was 2,685 microM in the action-potential experiments and 2,544 microM in the voltage- clamp experiments. An action potential released, on average, 0.14 of the SR Ca content with a peak rate of release of approximately 5%/ms. A second action potential, elicited 20 ms later, released only 0.6 times as much Ca (expressed as a fraction of the SR content), probably because Ca inactivation of Ca release was produced by the first action potential. During a depolarizing voltage step to 60 mV, the rate of Ca release rapidly increased to a peak value of approximately 3%/ms and then decreased to a quasi-steady level that was only 0.6 times as large; this decrease was also probably due to Ca inactivation of Ca release. SR Ca release was studied with small step depolarizations that open no more than one SR Ca channel in 7,000 and increase the value of spatially averaged myoplasmic free [Ca] by only 0.2 nM. PMID:8537818

DNA release from lipoplexes by anionic lipids: correlation with lipid mesomorphism, interfacial curvature, and membrane fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tarahovsky, Yury S.; Koynova, Rumiana; MacDonald, Robert C.

2010-01-18

DNA release from lipoplexes is an essential step during lipofection and is probably a result of charge neutralization by cellular anionic lipids. As a model system to test this possibility, fluorescence resonance energy transfer between DNA and lipid covalently labeled with Cy3 and BODIPY, respectively, was used to monitor the release of DNA from lipid surfaces induced by anionic liposomes. The separation of DNA from lipid measured this way was considerably slower and less complete than that estimated with noncovalently labeled DNA, and depends on the lipid composition of both lipoplexes and anionic liposomes. This result was confirmed by centrifugalmore » separation of released DNA and lipid. X-ray diffraction revealed a clear correlation of the DNA release capacity of the anionic lipids with the interfacial curvature of the mesomorphic structures developed when the anionic and cationic liposomes were mixed. DNA release also correlated with the rate of fusion of anionic liposomes with lipoplexes. It is concluded that the tendency to fuse and the phase preference of the mixed lipid membranes are key factors for the rate and extent of DNA release. The approach presented emphasizes the importance of the lipid composition of both lipoplexes and target membranes and suggests optimal transfection may be obtained by tailoring lipoplex composition to the lipid composition of target cells.« less

Factors influencing release of phosphorus from sediments in a high productive polymictic lake system.

PubMed

Solim, S U; Wanganeo, A

2009-01-01

Phosphorus (P) release rates from bottom sediments are high (20.6 mg/m(2)/day) in Dal Lake (India), a polymictic hyper-eutrophic lake. These gross release rates occur over a period of 72 days during summer only. Likewise, a net internal load of 11.3 tons was obtained from mass balance estimates. Significant proportion i.e. approximately 80% of 287.3 tons/yr of nitrate nitrogen (NO(3)-N) load is either eliminated by denitrification or gets entrapped for a short period in high macrophyte biomass of 3.2 kg/m(2) f.w., which eventually get decomposed and nitrogen (N) is released back. These processes result in low lake water NO(3)-N concentrations which potentially influence sediment phosphorus (P) release. Especially, nitrate nitrogen (NO(3)-N) <500 microg/L in the lake waters were associated with high P concentrations. Phosphorus was also observed to increase significantly in relation to temperature and pH, and it seems likely that release of phosphorus and ammonical nitrogen (NH(4)-N) depend on decomposition of rich reserves of organic matter (893 tons d.w. in superficial 10-cm bottom sediment layer). Lake P concentrations were significantly predicted by a multivariate regression model developed for the lake. This study describes significance of various lake water variables in relation to P-release from bottom sediments.

Atmospheric emission characterization of Marcellus shale natural gas development sites.

PubMed

Goetz, J Douglas; Floerchinger, Cody; Fortner, Edward C; Wormhoudt, Joda; Massoli, Paola; Knighton, W Berk; Herndon, Scott C; Kolb, Charles E; Knipping, Eladio; Shaw, Stephanie L; DeCarlo, Peter F

2015-06-02

Limited direct measurements of criteria pollutants emissions and precursors, as well as natural gas constituents, from Marcellus shale gas development activities contribute to uncertainty about their atmospheric impact. Real-time measurements were made with the Aerodyne Research Inc. Mobile Laboratory to characterize emission rates of atmospheric pollutants. Sites investigated include production well pads, a well pad with a drill rig, a well completion, and compressor stations. Tracer release ratio methods were used to estimate emission rates. A first-order correction factor was developed to account for errors introduced by fenceline tracer release. In contrast to observations from other shale plays, elevated volatile organic compounds, other than CH4 and C2H6, were generally not observed at the investigated sites. Elevated submicrometer particle mass concentrations were also generally not observed. Emission rates from compressor stations ranged from 0.006 to 0.162 tons per day (tpd) for NOx, 0.029 to 0.426 tpd for CO, and 67.9 to 371 tpd for CO2. CH4 and C2H6 emission rates from compressor stations ranged from 0.411 to 4.936 tpd and 0.023 to 0.062 tpd, respectively. Although limited in sample size, this study provides emission rate estimates for some processes in a newly developed natural gas resource and contributes valuable comparisons to other shale gas studies.

Photometric redshifts for Hyper Suprime-Cam Subaru Strategic Program Data Release 1

NASA Astrophysics Data System (ADS)

Tanaka, Masayuki; Coupon, Jean; Hsieh, Bau-Ching; Mineo, Sogo; Nishizawa, Atsushi J.; Speagle, Joshua; Furusawa, Hisanori; Miyazaki, Satoshi; Murayama, Hitoshi

2018-01-01

Photometric redshifts are a key component of many science objectives in the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). In this paper, we describe and compare the codes used to compute photometric redshifts for HSC-SSP, how we calibrate them, and the typical accuracy we achieve with the HSC five-band photometry (grizy). We introduce a new point estimator based on an improved loss function and demonstrate that it works better than other commonly used estimators. We find that our photo-z's are most accurate at 0.2 ≲ zphot ≲ 1.5, where we can straddle the 4000 Å break. We achieve σ[Δzphot/(1 + zphot)] ˜ 0.05 and an outlier rate of about 15% for galaxies down to i = 25 within this redshift range. If we limit ourselves to a brighter sample of i < 24, we achieve σ ˜ 0.04 and ˜8% outliers. Our photo-z's should thus enable many science cases for HSC-SSP. We also characterize the accuracy of our redshift probability distribution function (PDF) and discover that some codes over-/underestimate the redshift uncertainties, which has implications for N(z) reconstruction. Our photo-z products for the entire area in Public Data Release 1 are publicly available, and both our catalog products (such as point estimates) and full PDFs can be retrieved from the data release site, "https://hsc-release.mtk.nao.ac.jp/".

40 CFR 721.91 - Computation of estimated surface water concentrations: Instructions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... shall be computed for each site using the stream flow rate appropriate for the site according to... computing the equation, the number of kilograms released, and receiving stream flow. (a) Number of kilograms... chemical changes and/or changes in location, temperature, pressure, physical state, or similar...

40 CFR 721.91 - Computation of estimated surface water concentrations: Instructions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... shall be computed for each site using the stream flow rate appropriate for the site according to... computing the equation, the number of kilograms released, and receiving stream flow. (a) Number of kilograms... diagram which describes each manufacturing, processing, or use operation involving the substance. The...

40 CFR 721.91 - Computation of estimated surface water concentrations: Instructions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... shall be computed for each site using the stream flow rate appropriate for the site according to... computing the equation, the number of kilograms released, and receiving stream flow. (a) Number of kilograms... diagram which describes each manufacturing, processing, or use operation involving the substance. The...

Particulate matter in pack ice of the Beaufort Gyre

USGS Publications Warehouse

Reimnitz, E.; Barnes, P.W.; Weber, W.S.

1993-01-01

Fine sediment occurred in very small patches of turbid ice, as thin spotty surface layers, in mud pellets or in old snowdrifts. The latter were widespread south of 74??N, containing an estimated 22 tonnes of silt and clay km-2. Average particle concentration in sea ice (40 mg1-1) was much higher than in sea water (0.8 mg 1 -1) or in new snow. Assuming one-third of the load is released each year, the estimated deposition rate would equal the measured Holocene rate (~2cm 1000 year-1). Therefore, modern sea-ice rafting represents a substantial fraction of the total Arctic Ocean sediment budget. -from Authors

Introducing a decomposition rate modifier in the Rothamsted Carbon Model to predict soil organic carbon stocks in saline soils.

PubMed

Setia, Raj; Smith, Pete; Marschner, Petra; Baldock, Jeff; Chittleborough, David; Smith, Jo

2011-08-01

Soil organic carbon (SOC) models such as the Rothamsted Carbon Model (RothC) have been used to estimate SOC dynamics in soils over different time scales but, until recently, their ability to accurately predict SOC stocks/carbon dioxide (CO(2)) emissions from salt-affected soils has not been assessed. Given the large extent of salt-affected soils (19% of the 20.8 billion ha of arable land on Earth), this may lead to miss-estimation of CO(2) release. Using soils from two salt-affected regions (one in Punjab, India and one in South Australia), an incubation study was carried out measuring CO(2) release over 120 days. The soils varied both in salinity (measured as electrical conductivity (EC) and calculated as osmotic potential using EC and water content) and sodicity (measured as sodium adsorption ratio, SAR). For soils from both regions, the osmotic potential had a significant positive relationship with CO(2)-C release, but no significant relationship was found between SAR and CO(2)-C release. The monthly cumulative CO(2)-C was simulated using RothC. RothC was modified to take into account reductions in plant inputs due to salinity. A subset of non-salt-affected soils was used to derive an equation for a "lab-effect" modifier to account for changes in decomposition under lab conditions and this modifier was significantly related with pH. Using a subset of salt-affected soils, a decomposition rate modifier (as a function of osmotic potential) was developed to match measured and modelled CO(2)-C release after correcting for the lab effect. Using this decomposition rate modifier, we found an agreement (R(2) = 0.92) between modelled and independently measured data for a set of soils from the incubation experiment. RothC, modified by including reduced plant inputs due to salinity and the salinity decomposition rate modifier, was used to predict SOC stocks of soils in a field in South Australia. The predictions clearly showed that SOC stocks are reduced in saline soils. Therefore both the decomposition rate modifier and plant input modifier should be taken into account when accounting for SOC turnover in saline soils. Since modeling has previously not accounted for the impact of salinity, our results suggest that previous predictions may have overestimated SOC stocks.

A new approach to Ozone Depletion Potential (ODP) estimation

NASA Astrophysics Data System (ADS)

Portmann, R. W.; Daniel, J. S.; Yu, P.

2017-12-01

The Ozone Depletion Potential (ODP) is given by the time integrated global ozone loss of an ozone depleting substance (ODS) relative to a reference ODS (usually CFC-11). The ODP is used by the Montreal Protocol (and subsequent amendments) to inform policy decisions on the production of ODSs. Since the early 1990s, ODPs have usually been estimated using an approximate formulism that utilizes the lifetime and the fractional release factor of the ODS. This has the advantage that it can utilize measured concentrations of the ODSs to estimate their fractional release factors. However, there is a strong correlation between stratospheric lifetimes and fractional release factors of ODSs and that this can introduce uncertainties into ODP calculations when the terms are estimated independently. Instead, we show that the ODP is proportional to the average global ozone loss per equivalent chlorine molecule released in the stratosphere by the ODS loss process (which we call the Γ factor) and, importantly, this ratio varies only over a relatively small range ( 0.3-1.5) for ODPs with stratospheric lifetimes of 20 to more than 1,000 years. The Γ factor varies smoothly with stratospheric lifetime for ODSs with loss processes dominated by photolysis and is larger for long-lived species, while stratospheric OH loss processes produce relatively small Γs that are nearly independent of stratospheric lifetime. The fractional release approach does not accurately capture these relationships. We propose a new formulation that takes advantage of this smooth variation by parameterizing the Γ factor using ozone changes computed using the chemical climate model CESM-WACCM and the NOCAR two-dimensional model. We show that while the absolute Γ's vary between WACCM and NOCAR models, much of the difference is removed for the Γ/ΓCFC-11 ratio that is used in the ODP formula. This parameterized method simplifies the computation of ODPs while providing enhanced accuracy compared to the fractional release method and it can be used to estimate many ODPs given information on chemical reaction rates and photolysis processes.

Missed diagnoses of acute myocardial infarction in the emergency department: variation by patient and facility characteristics.

PubMed

Moy, Ernest; Barrett, Marguerite; Coffey, Rosanna; Hines, Anika L; Newman-Toker, David E

2015-02-01

An estimated 1.2 million people in the US have an acute myocardial infarction (AMI) each year. An estimated 7% of AMI hospitalizations result in death. Most patients experiencing acute coronary symptoms, such as unstable angina, visit an emergency department (ED). Some patients hospitalized with AMI after a treat-and-release ED visit likely represent missed opportunities for correct diagnosis and treatment. The purpose of the present study is to estimate the frequency of missed AMI or its precursors in the ED by examining use of EDs prior to hospitalization for AMI. We estimated the rate of probable missed diagnoses in EDs in the week before hospitalization for AMI and examined associated factors. We used Healthcare Cost and Utilization Project State Inpatient Databases and State Emergency Department Databases for 2007 to evaluate missed diagnoses in 111,973 admitted patients aged 18 years and older. We identified missed diagnoses in the ED for 993 of 112,000 patients (0.9% of all AMI admissions). These patients had visited an ED with chest pain or cardiac conditions, were released, and were subsequently admitted for AMI within 7 days. Higher odds of having missed diagnoses were associated with being younger and of Black race. Hospital teaching status, availability of cardiac catheterization, high ED admission rates, high inpatient occupancy rates, and urban location were associated with lower odds of missed diagnoses. Administrative data provide robust information that may help EDs identify populations at risk of experiencing a missed diagnosis, address disparities, and reduce diagnostic errors.

Estimation of Release of Nickel and Chromium by Indian Made Orthodontic Appliance in Saliva

PubMed Central

Parashar, Sandeep; Gupta, Ankur; Hegde, Chatura; Anand, Neelima

2015-01-01

Introduction With increasing use of Indian made orthodontic materials, need was felt to know nickel and chromium release from these material. Materials and Methods This study was conducted on simulated appliances consisting of brackets (022″Roth, Modern orthodontics, Ludhiana, India), from second premolar to central incisor, buccal tube and 0.019×0.025- inch SS arch wires secured with SS ligatures. Immersion was done in artificial saliva. Samples were analysed to using Atomic Absorption Photospectrometer (GVC ScientificEquipment Pvt. Ltd Australia) at AES Laboratories (P) Ltd., Noida India on 1st, 7th, 14th and 28th day. Results SPSS (ver 17, Inc., Chicago, Illinois, USA) was used toperform the statistical analysis. Descriptive statistics i.e. median and 25 and75 percentiles were used. Peak nickel release was on 7th day and subsequently declined over 14th and 28th day. The peak level of chromium concentration was on 14th day, which declined thereafter. Conclusion Average daily release of nickel and chromium over a period of one month was 97.368 μg/day and 47.664 μg/day respectively. The estimated release rates were approximately 32% and 16% of the reported average daily dietary. PMID:26501018

Fraction of organic carbon predicts labile desorption rates of chlorinated organic pollutants in laboratory-spiked geosorbents.

PubMed

Ginsbach, Jake W; Killops, Kato L; Olsen, Robert M; Peterson, Brittney; Dunnivant, Frank M

2010-05-01

The resuspension of large volumes of sediments that are contaminated with chlorinated pollutants continues to threaten environmental quality and human health. Whereas kinetic models are more accurate for estimating the environmental impact of these events, their widespread use is substantially hampered by the need for costly, time-consuming, site-specific kinetics experiments. The present study investigated the development of a predictive model for desorption rates from easily measurable sorbent and pollutant properties by examining the relationship between the fraction of organic carbon (fOC) and labile release rates. Duplicate desorption measurements were performed on 46 unique combinations of pollutants and sorbents with fOC values ranging from 0.001 to 0.150. Labile desorption rate constants indicate that release rates predominantly depend upon the fOC in the geosorbent. Previous theoretical models, such as the macro-mesopore and organic matter (MOM) diffusion model, have predicted such a relationship but could not accurately predict the experimental rate constants collected in the present study. An empirical model was successfully developed to correlate the labile desorption rate constant (krap) to the fraction of organic material where log(krap)=0.291-0.785 . log(fOC). These results provide the first experimental evidence that kinetic pollution releases during resuspension events are governed by the fOC content in natural geosorbents. Copyright (c) 2010 SETAC.

Estimation of recurrence interval of large earthquakes on the central Longmen Shan fault zone based on seismic moment accumulation/release model.

PubMed

Ren, Junjie; Zhang, Shimin

2013-01-01

Recurrence interval of large earthquake on an active fault zone is an important parameter in assessing seismic hazard. The 2008 Wenchuan earthquake (Mw 7.9) occurred on the central Longmen Shan fault zone and ruptured the Yingxiu-Beichuan fault (YBF) and the Guanxian-Jiangyou fault (GJF). However, there is a considerable discrepancy among recurrence intervals of large earthquake in preseismic and postseismic estimates based on slip rate and paleoseismologic results. Post-seismic trenches showed that the central Longmen Shan fault zone probably undertakes an event similar to the 2008 quake, suggesting a characteristic earthquake model. In this paper, we use the published seismogenic model of the 2008 earthquake based on Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data and construct a characteristic seismic moment accumulation/release model to estimate recurrence interval of large earthquakes on the central Longmen Shan fault zone. Our results show that the seismogenic zone accommodates a moment rate of (2.7 ± 0.3) × 10¹⁷ N m/yr, and a recurrence interval of 3900 ± 400 yrs is necessary for accumulation of strain energy equivalent to the 2008 earthquake. This study provides a preferred interval estimation of large earthquakes for seismic hazard analysis in the Longmen Shan region.

Estimation of Recurrence Interval of Large Earthquakes on the Central Longmen Shan Fault Zone Based on Seismic Moment Accumulation/Release Model

PubMed Central

Zhang, Shimin

2013-01-01

Recurrence interval of large earthquake on an active fault zone is an important parameter in assessing seismic hazard. The 2008 Wenchuan earthquake (Mw 7.9) occurred on the central Longmen Shan fault zone and ruptured the Yingxiu-Beichuan fault (YBF) and the Guanxian-Jiangyou fault (GJF). However, there is a considerable discrepancy among recurrence intervals of large earthquake in preseismic and postseismic estimates based on slip rate and paleoseismologic results. Post-seismic trenches showed that the central Longmen Shan fault zone probably undertakes an event similar to the 2008 quake, suggesting a characteristic earthquake model. In this paper, we use the published seismogenic model of the 2008 earthquake based on Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data and construct a characteristic seismic moment accumulation/release model to estimate recurrence interval of large earthquakes on the central Longmen Shan fault zone. Our results show that the seismogenic zone accommodates a moment rate of (2.7 ± 0.3) × 1017 N m/yr, and a recurrence interval of 3900 ± 400 yrs is necessary for accumulation of strain energy equivalent to the 2008 earthquake. This study provides a preferred interval estimation of large earthquakes for seismic hazard analysis in the Longmen Shan region. PMID:23878524

Illuminating pathways of forest nutrient provision: relative release from soil mineral and organic pools

NASA Astrophysics Data System (ADS)

Hauser, E.; Billings, S. A.

2017-12-01

Depletion of geogenic nutrients during soil weathering can prompt vegetation to rely on other sources, such as organic matter (OM) decay, to meet growth requirements. Weathered soils also tend to permit deep rooting, a phenomenon sometimes attributed to vegetation foraging for geogenic nutrients. This study examines the extent to which OM recycling provides nutrients to vegetation growing in soils with diverse weathering states. We thus address the fundamental problem of how forest vegetation obtains sufficient nutrition to support productivity despite wide variation in soils' nutrient contents. We hypothesized that vegetation growing on highly weathered soils relies on nutrients released from OM decay to a greater extent than vegetation growing on less weathered, more nutrient-rich substrates. For four mineralogically diverse Critical Zone Observatories (CZO) and Critical Zone Exploratory Network sites, we calculated weathering indices and approximated vegetation nutrient demand and nutrient release from OM decay. We also measured nutrient release rates from OM decay at each site. We then assessed the relationship between degree of soil weathering and the estimated fraction of nutrient demand satisfied by OM derived nutrients. Results are consistent with our hypothesis. The chemical index of alteration (CIA), a weathering index that increases in value with mineral depletion, varies predictably from 90 at the highly weathered Calhoun CZO to 60 at the Catalina CZO, where soils are more recently developed. Estimates of rates of K release from OM decay increase with CIA values. The highest release rate is 2.4 gK m-2 y-1 at Calhoun, accounting for 30% of annual vegetation K uptake; at Catalina, less than 0.5 gm-2 y-1 K is released, meeting 14% of vegetation demand. CIA also co-varies with rooting depth across sites: the deepest roots at the Calhoun sites are growing in soils with the highest CIA values, while the deepest roots at Catalina sites are growing in soils with much lower CIA values. Thus, provision of plant-available nutrients from OM decay appears greater at more weathered sites, and dominant nutrient sources accessed by deep roots (OM- vs. rock-derived) may vary predictably with soil weathering stage. On-going incubations will permit us to assess these relationships for multiple geogenic nutrients.

Inverse modelling of radionuclide release rates using gamma dose rate observations

NASA Astrophysics Data System (ADS)

Hamburger, Thomas; Evangeliou, Nikolaos; Stohl, Andreas; von Haustein, Christoph; Thummerer, Severin; Wallner, Christian

2015-04-01

Severe accidents in nuclear power plants such as the historical accident in Chernobyl 1986 or the more recent disaster in the Fukushima Dai-ichi nuclear power plant in 2011 have drastic impacts on the population and environment. Observations and dispersion modelling of the released radionuclides help to assess the regional impact of such nuclear accidents. Modelling the increase of regional radionuclide activity concentrations, which results from nuclear accidents, underlies a multiplicity of uncertainties. One of the most significant uncertainties is the estimation of the source term. That is, the time dependent quantification of the released spectrum of radionuclides during the course of the nuclear accident. The quantification of the source term may either remain uncertain (e.g. Chernobyl, Devell et al., 1995) or rely on estimates given by the operators of the nuclear power plant. Precise measurements are mostly missing due to practical limitations during the accident. The release rates of radionuclides at the accident site can be estimated using inverse modelling (Davoine and Bocquet, 2007). The accuracy of the method depends amongst others on the availability, reliability and the resolution in time and space of the used observations. Radionuclide activity concentrations are observed on a relatively sparse grid and the temporal resolution of available data may be low within the order of hours or a day. Gamma dose rates, on the other hand, are observed routinely on a much denser grid and higher temporal resolution and provide therefore a wider basis for inverse modelling (Saunier et al., 2013). We present a new inversion approach, which combines an atmospheric dispersion model and observations of radionuclide activity concentrations and gamma dose rates to obtain the source term of radionuclides. We use the Lagrangian particle dispersion model FLEXPART (Stohl et al., 1998; Stohl et al., 2005) to model the atmospheric transport of the released radionuclides. The inversion method uses a Bayesian formulation considering uncertainties for the a priori source term and the observations (Eckhardt et al., 2008, Stohl et al., 2012). The a priori information on the source term is a first guess. The gamma dose rate observations are used to improve the first guess and to retrieve a reliable source term. The details of this method will be presented at the conference. This work is funded by the Bundesamt für Strahlenschutz BfS, Forschungsvorhaben 3612S60026. References Davoine, X. and Bocquet, M., Atmos. Chem. Phys., 7, 1549-1564, 2007. Devell, L., et al., OCDE/GD(96)12, 1995. Eckhardt, S., et al., Atmos. Chem. Phys., 8, 3881-3897, 2008. Saunier, O., et al., Atmos. Chem. Phys., 13, 11403-11421, 2013. Stohl, A., et al., Atmos. Environ., 32, 4245-4264, 1998. Stohl, A., et al., Atmos. Chem. Phys., 5, 2461-2474, 2005. Stohl, A., et al., Atmos. Chem. Phys., 12, 2313-2343, 2012.

Gas Supersaturation May Reduce the Survival of Yearling Chinook Salmon in the Lower Columbia River and Ocean Plume

NASA Technical Reports Server (NTRS)

Brosnan, Ian; Welch, David; Scott, Melinda Jacobs

2015-01-01

Unusually high flows in the Columbia River in 2011 raised total dissolved gas (TDG) levels in the river above the 120 percent legal limit imposed to prevent harmful impacts to aquatic organisms. This provided a unique opportunity to evaluate the effect on smolt survival. In-river (IR) migrating juvenile yearling Chinook released at Bonneville Dam with acoustic tags during periods when TDG exceeded 120 percent received estimated maximum exposures of 134 TDG. Subsequent daily survival rates in the lower river and plume were reduced by 0.06 per day (SE equals 0.01) and 0.15 per day (SE equals 0.05) relative to IR migrant fish released when TDG was less than 120 percent. Transported smolts (T) released 10-13 kilometers below Bonneville Dam had lower maximum exposure levels (126 percent) and experienced no difference in daily survival rates relative to unexposed smolts. River temperature levels and trends in turbidity and disease prevalence between releases of high and low exposure smolts were not consistent with the observed effects on survival rates. We conclude that smolts may suffer from chronic effects of elevated TDG exposure while migrating through the Columbia River and plume. Consideration should be given to measuring these survival losses in an explicit experimental framework that isolates possible confounding factors.

Source term estimates of radioxenon released from the BaTek medical isotope production facility using external measured air concentrations.

PubMed

Eslinger, Paul W; Cameron, Ian M; Dumais, Johannes Robert; Imardjoko, Yudi; Marsoem, Pujadi; McIntyre, Justin I; Miley, Harry S; Stoehlker, Ulrich; Widodo, Susilo; Woods, Vincent T

2015-10-01

BATAN Teknologi (BaTek) operates an isotope production facility in Serpong, Indonesia that supplies (99m)Tc for use in medical procedures. Atmospheric releases of (133)Xe in the production process at BaTek are known to influence the measurements taken at the closest stations of the radionuclide network of the International Monitoring System (IMS). The purpose of the IMS is to detect evidence of nuclear explosions, including atmospheric releases of radionuclides. The major xenon isotopes released from BaTek are also produced in a nuclear explosion, but the isotopic ratios are different. Knowledge of the magnitude of releases from the isotope production facility helps inform analysts trying to decide if a specific measurement result could have originated from a nuclear explosion. A stack monitor deployed at BaTek in 2013 measured releases to the atmosphere for several isotopes. The facility operates on a weekly cycle, and the stack data for June 15-21, 2013 show a release of 1.84 × 10(13) Bq of (133)Xe. Concentrations of (133)Xe in the air are available at the same time from a xenon sampler located 14 km from BaTek. An optimization process using atmospheric transport modeling and the sampler air concentrations produced a release estimate of 1.88 × 10(13) Bq. The same optimization process yielded a release estimate of 1.70 × 10(13) Bq for a different week in 2012. The stack release value and the two optimized estimates are all within 10% of each other. Unpublished production data and the release estimate from June 2013 yield a rough annual release estimate of 8 × 10(14) Bq of (133)Xe in 2014. These multiple lines of evidence cross-validate the stack release estimates and the release estimates based on atmospheric samplers. Copyright © 2015 Elsevier Ltd. All rights reserved.

RCRA/UST, superfund, and EPCRA hotline training module. Introduction to toxics release inventory: Estimating releases (EPCRA section 313; 40 CFR part 372). Updated as of November 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-03-01

The module provides an overview of general techniques that owners and operators of reporting facilities may use to estimate their toxic chemical releases. It exlains the basic release estimation techniques used to determine the chemical quantities reported on the Form R and uses those techniques, along with fundamental chemical or physical principles and properties, to estimate releases of listed toxic chemicals. It converts units of mass, volume, and time. It states the rules governing significant figures and rounding techniques, and references general and industry-specific estimation documents.

Combined statistical analysis of landslide release and propagation

NASA Astrophysics Data System (ADS)

Mergili, Martin; Rohmaneo, Mohammad; Chu, Hone-Jay

2016-04-01

Statistical methods - often coupled with stochastic concepts - are commonly employed to relate areas affected by landslides with environmental layers, and to estimate spatial landslide probabilities by applying these relationships. However, such methods only concern the release of landslides, disregarding their motion. Conceptual models for mass flow routing are used for estimating landslide travel distances and possible impact areas. Automated approaches combining release and impact probabilities are rare. The present work attempts to fill this gap by a fully automated procedure combining statistical and stochastic elements, building on the open source GRASS GIS software: (1) The landslide inventory is subset into release and deposition zones. (2) We employ a traditional statistical approach to estimate the spatial release probability of landslides. (3) We back-calculate the probability distribution of the angle of reach of the observed landslides, employing the software tool r.randomwalk. One set of random walks is routed downslope from each pixel defined as release area. Each random walk stops when leaving the observed impact area of the landslide. (4) The cumulative probability function (cdf) derived in (3) is used as input to route a set of random walks downslope from each pixel in the study area through the DEM, assigning the probability gained from the cdf to each pixel along the path (impact probability). The impact probability of a pixel is defined as the average impact probability of all sets of random walks impacting a pixel. Further, the average release probabilities of the release pixels of all sets of random walks impacting a given pixel are stored along with the area of the possible release zone. (5) We compute the zonal release probability by increasing the release probability according to the size of the release zone - the larger the zone, the larger the probability that a landslide will originate from at least one pixel within this zone. We quantify this relationship by a set of empirical curves. (6) Finally, we multiply the zonal release probability with the impact probability in order to estimate the combined impact probability for each pixel. We demonstrate the model with a 167 km² study area in Taiwan, using an inventory of landslides triggered by the typhoon Morakot. Analyzing the model results leads us to a set of key conclusions: (i) The average composite impact probability over the entire study area corresponds well to the density of observed landside pixels. Therefore we conclude that the method is valid in general, even though the concept of the zonal release probability bears some conceptual issues that have to be kept in mind. (ii) The parameters used as predictors cannot fully explain the observed distribution of landslides. The size of the release zone influences the composite impact probability to a larger degree than the pixel-based release probability. (iii) The prediction rate increases considerably when excluding the largest, deep-seated, landslides from the analysis. We conclude that such landslides are mainly related to geological features hardly reflected in the predictor layers used.

Using generalized linear models to estimate selectivity from short-term recoveries of tagged red drum Sciaenops ocellatus: Effects of gear, fate, and regulation period

USGS Publications Warehouse

Bacheler, N.M.; Hightower, J.E.; Burdick, S.M.; Paramore, L.M.; Buckel, J.A.; Pollock, K.H.

2010-01-01

Estimating the selectivity patterns of various fishing gears is a critical component of fisheries stock assessment due to the difficulty in obtaining representative samples from most gears. We used short-term recoveries (n = 3587) of tagged red drum Sciaenops ocellatus to directly estimate age- and length-based selectivity patterns using generalized linear models. The most parsimonious models were selected using AIC, and standard deviations were estimated using simulations. Selectivity of red drum was dependent upon the regulation period in which the fish was caught, the gear used to catch the fish (i.e., hook-and-line, gill nets, pound nets), and the fate of the fish upon recovery (i.e., harvested or released); models including all first-order interactions between main effects outperformed models without interactions. Selectivity of harvested fish was generally dome-shaped and shifted toward larger, older fish in response to regulation changes. Selectivity of caught-and-released red drum was highest on the youngest and smallest fish in the early and middle regulation periods, but increased on larger, legal-sized fish in the late regulation period. These results suggest that catch-and-release mortality has consistently been high for small, young red drum, but has recently become more common in larger, older fish. This method of estimating selectivity from short-term tag recoveries is valuable because it is simpler than full tag-return models, and may be more robust because yearly fishing and natural mortality rates do not need to be modeled and estimated. ?? 2009 Elsevier B.V.

Using generalized linear models to estimate selectivity from short-term recoveries of tagged red drum Sciaenops ocellatus: Effects of gear, fate, and regulation period

USGS Publications Warehouse

Burdick, Summer M.; Hightower, Joseph E.; Bacheler, Nathan M.; Paramore, Lee M.; Buckel, Jeffrey A.; Pollock, Kenneth H.

2010-01-01

Estimating the selectivity patterns of various fishing gears is a critical component of fisheries stock assessment due to the difficulty in obtaining representative samples from most gears. We used short-term recoveries (n = 3587) of tagged red drum Sciaenops ocellatus to directly estimate age- and length-based selectivity patterns using generalized linear models. The most parsimonious models were selected using AIC, and standard deviations were estimated using simulations. Selectivity of red drum was dependent upon the regulation period in which the fish was caught, the gear used to catch the fish (i.e., hook-and-line, gill nets, pound nets), and the fate of the fish upon recovery (i.e., harvested or released); models including all first-order interactions between main effects outperformed models without interactions. Selectivity of harvested fish was generally dome-shaped and shifted toward larger, older fish in response to regulation changes. Selectivity of caught-and-released red drum was highest on the youngest and smallest fish in the early and middle regulation periods, but increased on larger, legal-sized fish in the late regulation period. These results suggest that catch-and-release mortality has consistently been high for small, young red drum, but has recently become more common in larger, older fish. This method of estimating selectivity from short-term tag recoveries is valuable because it is simpler than full tag-return models, and may be more robust because yearly fishing and natural mortality rates do not need to be modeled and estimated.

77 FR 15187 - Released Rates of Motor Common Carriers of Household Goods

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-14

... available cargo-liability options \\2\\ on the written estimate form--the first form that a moving company...-goods freight forwarders. Finally, the Board established April 2, 2011, as the effective date for moving companies to comply with the changes outlined in the two decisions. These Board decisions are available on...

Incidence of Posttransplantation Diabetes Mellitus in De Novo Kidney Transplant Recipients Receiving Prolonged-Release Tacrolimus-Based Immunosuppression With 2 Different Corticosteroid Minimization Strategies: ADVANCE, A Randomized Controlled Trial.

PubMed

Mourad, Georges; Glyda, Maciej; Albano, Laetitia; Viklický, Ondrej; Merville, Pierre; Tydén, Gunnar; Mourad, Michel; Lõhmus, Aleksander; Witzke, Oliver; Christiaans, Maarten H L; Brown, Malcolm W; Undre, Nasrullah; Kazeem, Gbenga; Kuypers, Dirk R J

2017-08-01

ADVANCE (NCT01304836) was a phase 4, multicenter, prospectively randomized, open-label, 24-week study comparing the incidence of posttransplantation diabetes mellitus (PTDM) with 2 prolonged-release tacrolimus corticosteroid minimization regimens. All patients received prolonged-release tacrolimus, basiliximab, mycophenolate mofetil and 1 bolus of intraoperative corticosteroids (0-1000 mg) as per center policy. Patients in arm 1 received tapered corticosteroids, stopped after day 10, whereas patients in arm 2 received no steroids after the intraoperative bolus. The primary efficacy variable was the diagnosis of PTDM as per American Diabetes Association criteria (2010) at any point up to 24 weeks postkidney transplantation. Secondary efficacy variables included incidence of composite efficacy failure (graft loss, biopsy-proven acute rejection or severe graft dysfunction: estimated glomerular filtration rate (Modification of Diet in Renal Disease-4) <30 mL/min per 1.73 m), acute rejection and graft and patient survival. The full-analysis set included 1081 patients (arm 1: n = 528, arm 2: n = 553). Baseline characteristics and mean tacrolimus trough levels were comparable between arms. Week 24 Kaplan-Meier estimates of PTDM were similar for arm 1 versus arm 2 (17.4% vs 16.6%; P = 0.579). Incidence of composite efficacy failure, graft and patient survival, and mean estimated glomerular filtration rate were also comparable between arms. Biopsy-proven acute rejection and acute rejection were significantly higher in arm 2 versus arm 1 (13.6% vs 8.7%, P = 0.006 and 25.9% vs 18.2%, P = 0.001, respectively). Tolerability profiles were comparable between arms. A prolonged-release tacrolimus, basiliximab, and mycophenolate mofetil immunosuppressive regimen is efficacious, with a low incidence of PTDM and a manageable tolerability profile over 24 weeks of treatment. A lower incidence of biopsy-proven acute rejection was seen in patients receiving corticosteroids tapered over 10 days plus an intraoperative corticosteroid bolus versus those receiving an intraoperative bolus only.

Potential for Water Savings by Defoliation of Saltcedar (Tamarix spp.) by Saltcedar Beetles (Diorhabda carinulata) in the Upper Colorado River Basin

NASA Astrophysics Data System (ADS)

Nagler, P. L.; Nguyen, U.; Bateman, H. L.; Jarchow, C.; van Riper, C., III; Waugh, W.; Glenn, E.

2016-12-01

Northern saltcedar beetles (Diorhabda carinata) have spread widely in riparian zones on the Colorado Plateau since their initial release in 2002. One goal of the releases was to reduce water consumption by saltcedar in order to conserve water through reduction of evapotranspiration (ET). The beetle moved south on the Virgin River and reached Big Bend State Park in Nevada in 2014, an expansion rate of 60 km/year. This is important because the beetle's photoperiod requirement for diapause was expected to prevent them from moving south of 37°N latitude, where endangered southwest willow flycatcher habitat occurs. In addition to focusing on the rate of dispersal of the beetles, we used remote sensing estimates of ET at 13 sites on the Colorado, San Juan, Virgin and Dolores rivers and their tributaries to estimate riparian zone ET before and after beetle releases. We estimate that water savings from 2007-2015 was 31.5 million m3/yr (25,547 acre-ft/yr), amounting to 0.258 % of annual river flow from the Upper Colorado River Basin to the Lower Basin. Reasons for the relatively low potential water savings are: 1) baseline ET before beetle release was modest (0.472 m/yr); 2) reduction in ET was low (0.061 m/yr) because saltcedar stands tended to recover after defoliation; 3) riparian ET even in the absence of beetles was only 1.8 % of river flows, calculated as the before beetle average annual ET (472 mm/yr) times the total area of saltcedar (51,588 ha) divided by the combined total average annual flows (1964-2015) from the upper to lower catchment areas of the Colorado River Basin at the USGS gages (12,215 million m3/yr or 9.90 million acre-ft). Further research is suggested to concentrate on the ecological impacts (both positive and negative) of beetles on riparian zones and on identifying management options to maximize riparian health.

Review of flow rate estimates of the Deepwater Horizon oil spill.

PubMed

McNutt, Marcia K; Camilli, Rich; Crone, Timothy J; Guthrie, George D; Hsieh, Paul A; Ryerson, Thomas B; Savas, Omer; Shaffer, Frank

2012-12-11

The unprecedented nature of the Deepwater Horizon oil spill required the application of research methods to estimate the rate at which oil was escaping from the well in the deep sea, its disposition after it entered the ocean, and total reservoir depletion. Here, we review what advances were made in scientific understanding of quantification of flow rates during deep sea oil well blowouts. We assess the degree to which a consensus was reached on the flow rate of the well by comparing in situ observations of the leaking well with a time-dependent flow rate model derived from pressure readings taken after the Macondo well was shut in for the well integrity test. Model simulations also proved valuable for predicting the effect of partial deployment of the blowout preventer rams on flow rate. Taken together, the scientific analyses support flow rates in the range of ∼50,000-70,000 barrels/d, perhaps modestly decreasing over the duration of the oil spill, for a total release of ∼5.0 million barrels of oil, not accounting for BP's collection effort. By quantifying the amount of oil at different locations (wellhead, ocean surface, and atmosphere), we conclude that just over 2 million barrels of oil (after accounting for containment) and all of the released methane remained in the deep sea. By better understanding the fate of the hydrocarbons, the total discharge can be partitioned into separate components that pose threats to deep sea vs. coastal ecosystems, allowing responders in future events to scale their actions accordingly.

Review of flow rate estimates of the Deepwater Horizon oil spill

USGS Publications Warehouse

McNutt, Marcia K.; Camilli, Rich; Crone, Timothy J.; Guthrie, George D.; Hsieh, Paul A.; Ryerson, Thomas B.; Savas, Omer; Shaffer, Frank

2012-01-01

The unprecedented nature of the Deepwater Horizon oil spill required the application of research methods to estimate the rate at which oil was escaping from the well in the deep sea, its disposition after it entered the ocean, and total reservoir depletion. Here, we review what advances were made in scientific understanding of quantification of flow rates during deep sea oil well blowouts. We assess the degree to which a consensus was reached on the flow rate of the well by comparing in situ observations of the leaking well with a time-dependent flow rate model derived from pressure readings taken after the Macondo well was shut in for the well integrity test. Model simulations also proved valuable for predicting the effect of partial deployment of the blowout preventer rams on flow rate. Taken together, the scientific analyses support flow rates in the range of ~50,000–70,000 barrels/d, perhaps modestly decreasing over the duration of the oil spill, for a total release of ~5.0 million barrels of oil, not accounting for BP's collection effort. By quantifying the amount of oil at different locations (wellhead, ocean surface, and atmosphere), we conclude that just over 2 million barrels of oil (after accounting for containment) and all of the released methane remained in the deep sea. By better understanding the fate of the hydrocarbons, the total discharge can be partitioned into separate components that pose threats to deep sea vs. coastal ecosystems, allowing responders in future events to scale their actions accordingly.

Review of flow rate estimates of the Deepwater Horizon oil spill

PubMed Central

McNutt, Marcia K.; Camilli, Rich; Crone, Timothy J.; Guthrie, George D.; Hsieh, Paul A.; Ryerson, Thomas B.; Savas, Omer; Shaffer, Frank

2012-01-01

The unprecedented nature of the Deepwater Horizon oil spill required the application of research methods to estimate the rate at which oil was escaping from the well in the deep sea, its disposition after it entered the ocean, and total reservoir depletion. Here, we review what advances were made in scientific understanding of quantification of flow rates during deep sea oil well blowouts. We assess the degree to which a consensus was reached on the flow rate of the well by comparing in situ observations of the leaking well with a time-dependent flow rate model derived from pressure readings taken after the Macondo well was shut in for the well integrity test. Model simulations also proved valuable for predicting the effect of partial deployment of the blowout preventer rams on flow rate. Taken together, the scientific analyses support flow rates in the range of ∼50,000–70,000 barrels/d, perhaps modestly decreasing over the duration of the oil spill, for a total release of ∼5.0 million barrels of oil, not accounting for BP's collection effort. By quantifying the amount of oil at different locations (wellhead, ocean surface, and atmosphere), we conclude that just over 2 million barrels of oil (after accounting for containment) and all of the released methane remained in the deep sea. By better understanding the fate of the hydrocarbons, the total discharge can be partitioned into separate components that pose threats to deep sea vs. coastal ecosystems, allowing responders in future events to scale their actions accordingly. PMID:22187459

Quantitative measurement of protein digestion in simulated gastric fluid.

PubMed

Herman, Rod A; Korjagin, Valerie A; Schafer, Barry W

2005-04-01

The digestibility of novel proteins in simulated gastric fluid is considered to be an indicator of reduced risk of allergenic potential in food, and estimates of digestibility for transgenic proteins expressed in crops are required for making a human-health risk assessment by regulatory authorities. The estimation of first-order rate constants for digestion under conditions of low substrate concentration was explored for two protein substrates (azocoll and DQ-ovalbumin). Data conformed to first-order kinetics, and half-lives were relatively insensitive to significant variations in both substrate and pepsin concentration when high purity pepsin preparations were used. Estimation of digestion efficiency using densitometric measurements of relative protein concentration based on SDS-PAGE corroborated digestion estimates based on measurements of dye or fluorescence release from the labeled substrates. The suitability of first-order rate constants for estimating the efficiency of the pepsin digestion of novel proteins is discussed. Results further support a kinetic approach as appropriate for comparing the digestibility of proteins in simulated gastric fluid.

Survival estimation and the effects of dependency among animals

USGS Publications Warehouse

Schmutz, Joel A.; Ward, David H.; Sedinger, James S.; Rexstad, Eric A.

1995-01-01

Survival models assume that fates of individuals are independent, yet the robustness of this assumption has been poorly quantified. We examine how empirically derived estimates of the variance of survival rates are affected by dependency in survival probability among individuals. We used Monte Carlo simulations to generate known amounts of dependency among pairs of individuals and analyzed these data with Kaplan-Meier and Cormack-Jolly-Seber models. Dependency significantly increased these empirical variances as compared to theoretically derived estimates of variance from the same populations. Using resighting data from 168 pairs of black brant, we used a resampling procedure and program RELEASE to estimate empirical and mean theoretical variances. We estimated that the relationship between paired individuals caused the empirical variance of the survival rate to be 155% larger than the empirical variance for unpaired individuals. Monte Carlo simulations and use of this resampling strategy can provide investigators with information on how robust their data are to this common assumption of independent survival probabilities.

Drug-related death following release from prison: a brief review of the literature with recommendations for practice.

PubMed

Leach, D; Oliver, P

2011-12-01

Mortality from drug-related death is a significant contributor to the loss of life of young people in the UK. Despite attention, the high death rate from this cause continues to persist. One of the most frequently cited factors involved in drug-related death (DRD) is release from prison. This review aims to examine the published literature with a view to quantifying the risk associated with recent prison release and identifying risk factors and prevention strategies. Most deaths following release from prison are caused by overdose, usually from opioid use. The risk of death is greatest within the first week of release but, when compared with the general population, continues to be elevated for several weeks. Relative risk estimates suggest that those released from prison are up to 40 times more likely to die than similar individuals from the general population. Other than gender and an association with poor mental health, there is little in the way of robust risk factors for post-release death that could be identified from the literature. In-prison pharmacological maintenance treatment with methadone and buprenorphine has been shown to reduce the rate of heroin use, in the period immediately following release, in a small number of randomised controlled trials. It is widely recognised that continuity of care, of any form, is critical in avoiding DRDs. For problem drug users, packages of education, including information on the associated risks, treatments, and recognition of DRD after release from prison, are seen as a basic minimum requirement of the prison services. However, special protocols may be required for those drug-using prisoners who have a possibility of being released at short notice.

Long‐term creep rates on the Hayward Fault: evidence for controls on the size and frequency of large earthquakes

USGS Publications Warehouse

Lienkaemper, James J.; McFarland, Forrest S.; Simpson, Robert W.; Bilham, Roger; Ponce, David A.; Boatwright, John; Caskey, S. John

2012-01-01

The Hayward fault (HF) in California exhibits large (Mw 6.5–7.1) earthquakes with short recurrence times (161±65 yr), probably kept short by a 26%–78% aseismic release rate (including postseismic). Its interseismic release rate varies locally over time, as we infer from many decades of surface creep data. Earliest estimates of creep rate, primarily from infrequent surveys of offset cultural features, revealed distinct spatial variation in rates along the fault, but no detectable temporal variation. Since the 1989 Mw 6.9 Loma Prieta earthquake (LPE), monitoring on 32 alinement arrays and 5 creepmeters has greatly improved the spatial and temporal resolution of creep rate. We now identify significant temporal variations, mostly associated with local and regional earthquakes. The largest rate change was a 6‐yr cessation of creep along a 5‐km length near the south end of the HF, attributed to a regional stress drop from the LPE, ending in 1996 with a 2‐cm creep event. North of there near Union City starting in 1991, rates apparently increased by 25% above pre‐LPE levels on a 16‐km‐long reach of the fault. Near Oakland in 2007 an Mw 4.2 earthquake initiated a 1–2 cm creep event extending 10–15 km along the fault. Using new better‐constrained long‐term creep rates, we updated earlier estimates of depth to locking along the HF. The locking depths outline a single, ∼50‐km‐long locked or retarded patch with the potential for an Mw∼6.8 event equaling the 1868 HF earthquake. We propose that this inferred patch regulates the size and frequency of large earthquakes on HF.

On the possible long-term fate of oil released in the deepwater horizon incident: estimated by ensembles of dye release simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maltrud, Mathew E.; Peacock, Synte L.; Visbeck, Martin

2010-08-01

We have conducted an ensemble of 20 simulations using a high-resolution global ocean model in which dye was continuously injected at the site of the Deepwater Horizon drilling rig for two months. We then extended these simulations for another four months to track the dispersal of the dye in the model. We have also performed five simulations in which dye was continuously injected at the site of the spill for four months and then run out to one year from the initial spill date. The experiments can elucidate the time and space scales of dispersal of polluted waters and alsomore » give a quantitative estimate of dilution rate, ignoring any sink terms such as chemical or biological degradation.« less

Extended release dosage form of glipizide: development and validation of a level A in vitro-in vivo correlation.

PubMed

Ghosh, Animesh; Bhaumik, Uttam Kumar; Bose, Anirbandeep; Mandal, Uttam; Gowda, Veeran; Chatterjee, Bappaditya; Chakrabarty, Uday Sankar; Pal, Tapan Kumar

2008-10-01

Defining a quantitative and reliable relationship between in vitro drug release and in vivo absorption is highly desired for rational development, optimization, and evaluation of controlled-release dosage forms and manufacturing process. During the development of once daily extended-release (ER) tablet of glipizide, a predictive in vitro drug release method was designed and statistically evaluated using three formulations with varying release rates. In order to establish internally and externally validated level A in vitro-in vivo correlation (IVIVC), a total of three different ER formulations of glipizide were used to evaluate a linear IVIVC model based on the in vitro test method. For internal validation, a single-dose four-way cross over study (n=6) was performed using fast-, moderate-, and slow-releasing ER formulations and an immediate-release (IR) of glipizide as reference. In vitro release rate data were obtained for each formulation using the United States Pharmacopeia (USP) apparatus II, paddle stirrer at 50 and 100 rev. min(-1) in 0.1 M hydrochloric acid (HCl) and pH 6.8 phosphate buffer. The f(2) metric (similarity factor) was used to analyze the dissolution data. The formulations were compared using area under the plasma concentration-time curve, AUC(0-infinity), time to reach peak plasma concentration, T(max), and peak plasma concentration, C(max), while correlation was determined between in vitro release and in vivo absorption. A linear correlation model was developed using percent absorbed data versus percent dissolved from the three formulations. Predicted glipizide concentrations were obtained by convolution of the in vivo absorption rates. Prediction errors were estimated for C(max) and AUC(0-infinity) to determine the validity of the correlation. Apparatus II, pH 6.8 at 100 rev. min(-1) was found to be the most discriminating dissolution method. Linear regression analysis of the mean percentage of dose absorbed versus the mean percentage of in vitro release resulted in a significant correlation (r(2)>or=0.9) for the three formulations.

Dynamic Model for the Stocks and Release Flows of Engineered Nanomaterials.

PubMed

Song, Runsheng; Qin, Yuwei; Suh, Sangwon; Keller, Arturo A

2017-11-07

Most existing life-cycle release models for engineered nanomaterials (ENM) are static, ignoring the dynamics of stock and flows of ENMs. Our model, nanoRelease, estimates the annual releases of ENMs from manufacturing, use, and disposal of a product explicitly taking stock and flow dynamics into account. Given the variabilities in key parameters (e.g., service life of products and annual release rate during use) nanoRelease is designed as a stochastic model. We apply nanoRelease to three ENMs (TiO 2 , SiO 2 and FeO x ) used in paints and coatings through seven product applications, including construction and building, household and furniture, and automotive for the period from 2000 to 2020 using production volume and market projection information. We also consider model uncertainties using Monte Carlo simulation. Compared with 2016, the total annual releases of ENMs in 2020 will increase by 34-40%, and the stock will increase by 28-34%. The fraction of the end-of-life release among total release flows will increase from 11% in 2002 to 43% in 2020. As compared to static models, our dynamic model predicts about an order of magnitude lower values for the amount of ENM released from this sector in the near-term while stock continues to build up in the system.

Behavior patterns and fates of adult steelhead, Chinook salmon, and coho salmon released into the upper Cowlitz River Basin, 2005–09 and 2012, Washington

USGS Publications Warehouse

Kock, Tobias J.; Ekstrom, Brian K.; Liedtke, Theresa L.; Serl, John D.; Kohn, Mike

2016-08-26

A multiyear radiotelemetry evaluation was conducted to monitor adult steelhead (Oncorhynchus mykiss), Chinook salmon (O. tshawytscha), and coho salmon (O. kisutch) behavior and movement patterns in the upper Cowlitz River Basin. Volitional passage to this area was eliminated by dam construction in the mid-1960s, and a reintroduction program began in the mid-1990s. Fish are transported around the dams using a trap-and-haul program, and adult release sites are located in Lake Scanewa, the uppermost reservoir in the system, and in the Cowlitz and Cispus Rivers. Our goal was to estimate the proportion of tagged fish that fell back downstream of Cowlitz Falls Dam before the spawning period and to determine the proportion that were present in the Cowlitz and Cispus Rivers during the spawning period. Fallback is important because Cowlitz Falls Dam does not have upstream fish passage, so fish that pass the dam are unable to move back upstream and spawn. A total of 2,051 steelhead and salmon were tagged for the study, which was conducted during 2005–09 and 2012, and 173 (8.4 percent) of these regurgitated their transmitter prior to, or shortly after release. Once these fish were removed from the dataset, the final number of fish that was monitored totaled 1,878 fish, including 647 steelhead, 770 Chinook salmon, and 461 coho salmon.Hatchery-origin (HOR) and natural-origin (NOR) steelhead, Chinook salmon, and coho salmon behaved differently following release into Lake Scanewa. Detection records showed that the percentage of HOR fish that moved upstream and entered the Cowlitz River or Cispus River after release was relatively low (steelhead = 38 percent; Chinook salmon = 67 percent; coho salmon = 41 percent) compared to NOR fish (steelhead = 84 percent; Chinook salmon = 82 percent; coho salmon = 76 percent). The elapsed time from release to river entry was significantly lower for NOR fish than for HOR fish for all three species. Tagged fish entered the Cowlitz River in greater proportions than the Cispus River, regardless of origin. We found that 23–47 percent of the HOR fish entered the Cowlitz River and 12–38 percent entered the Cispus River. Similarly, 67–70 percent of the NOR fish entered the Cowlitz River and 38–66 percent entered the Cispus River. These behavioral differences translated into similar differences in fates during the spawning periods as higher percentages of tagged fish were assigned Cowlitz River fates than Cispus River fates.Fallback rates were affected by fish origin and release site. Overall, 12 percent of steelhead, 19 percent of Chinook salmon, and 8 percent of coho salmon fell back downstream of Cowlitz Falls Dam prior to spawning. Fallback rates were lower for fish that were released in the Cowlitz River or the Cispus River than for reservoir-released fish, but statistical comparisons were not robust because of small sample sizes at the river release sites. Fallback rates for fish released at the river release sites were 10 percent lower for steelhead, 4 percent lower for Chinook salmon, and 9 percent lower for coho salmon than for reservoir-released fish. However, fallback rates also were different between HOR and NOR fish. Fallback rates were significantly higher for HOR reservoir-released fish than for NOR reservoir-released fish.This study provided data that were insightful for understanding behavior and movement patterns in the upper Cowlitz River Basin and yielded estimates of fallback rates and fish fates that may be useful for fishery managers in the years to come. Studies from other systems have shown that factors such as prespawn mortality and fallback have resulted in substantial losses to spawning populations where trap-and-haul programs are being used as a restoration tool. Future research in the upper Cowlitz River Basin may use additional telemetry studies, genetic analyses, and spawning ground surveys to provide answers for new questions and to continue to monitor the progress of the reintroduction effort.

Sensitivity of the global submarine hydrate inventory to scenarios of future climate change

NASA Astrophysics Data System (ADS)

Hunter, S. J.; Goldobin, D. S.; Haywood, A. M.; Ridgwell, A.; Rees, J. G.

2013-04-01

The global submarine inventory of methane hydrate is thought to be considerable. The stability of marine hydrates is sensitive to changes in temperature and pressure and once destabilised, hydrates release methane into sediments and ocean and potentially into the atmosphere, creating a positive feedback with climate change. Here we present results from a multi-model study investigating how the methane hydrate inventory dynamically responds to different scenarios of future climate and sea level change. The results indicate that a warming-induced reduction is dominant even when assuming rather extreme rates of sea level rise (up to 20 mm yr-1) under moderate warming scenarios (RCP 4.5). Over the next century modelled hydrate dissociation is focussed in the top ˜100m of Arctic and Subarctic sediments beneath <500m water depth. Predicted dissociation rates are particularly sensitive to the modelled vertical hydrate distribution within sediments. Under the worst case business-as-usual scenario (RCP 8.5), upper estimates of resulting global sea-floor methane fluxes could exceed estimates of natural global fluxes by 2100 (>30-50TgCH4yr-1), although subsequent oxidation in the water column could reduce peak atmospheric release rates to 0.75-1.4 Tg CH4 yr-1.

Characterization of Mode 1 and Mode 2 delamination growth and thresholds in graphite/peek composites

NASA Technical Reports Server (NTRS)

Martin, Roderick H.; Murri, Gretchen B.

1988-01-01

Composite materials often fail by delamination. The onset and growth of delamination in AS4/PEEK, a tough thermoplastic matrix composite, was characterized for mode 1 and mode 2 loadings, using the Double Cantilever Beam (DCB) and the End Notched Flexure (ENF) test specimens. Delamination growth per fatigue cycle, da/dN, was related to strain energy release rate, G, by means of a power law. However, the exponents of these power laws were too large for them to be adequately used as a life prediction tool. A small error in the estimated applied loads could lead to large errors in the delamination growth rates. Hence strain energy release rate thresholds, G sub th, below which no delamination would occur were also measured. Mode 1 and 2 threshold G values for no delamination growth were found by monitoring the number of cycles to delamination onset in the DCB and ENF specimens. The maximum applied G for which no delamination growth had occurred until at least 1,000,000 cycles was considered the threshold strain energy release rate. Comments are given on how testing effects, facial interference or delamination front damage, may invalidate the experimental determination of the constants in the expression.

Characterization of Mode I and Mode II delamination growth and thresholds in AS4/PEEK composites

NASA Technical Reports Server (NTRS)

Martin, Roderick H.; Murri, Gretchen Bostaph

1990-01-01

Composite materials often fail by delamination. The onset and growth of delamination in AS4/PEEK, a tough thermoplastic matrix composite, was characterized for mode 1 and mode 2 loadings, using the Double Cantilever Beam (DCB) and the End Notched Flexure (ENF) test specimens. Delamination growth per fatigue cycle, da/dN, was related to strain energy release rate, G, by means of a power law. However, the exponents of these power laws were too large for them to be adequately used as a life prediction tool. A small error in the estimated applied loads could lead to large errors in the delamination growth rates. Hence strain energy release rate thresholds, G sub th, below which no delamination would occur were also measured. Mode 1 and 2 threshold G values for no delamination growth were found by monitoring the number of cycles to delamination onset in the DCB and ENF specimens. The maximum applied G for which no delamination growth had occurred until at least 1,000,000 cycles was considered the threshold strain energy release rate. Comments are given on how testing effects, facial interference or delamination front damage, may invalidate the experimental determination of the constants in the expression.

Survival Estimates for the Passage of Juvenile Chinook Salmon through Snake River Dams and Reservoirs, 1993 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iwamoto, Robert N.; Sandford, Benjamin P.; McIntyre, Kenneth W.

1994-04-01

A pilot study was conducted to estimate survival of hatchery-reared yearling chinook salmon through dams and reservoirs on the Snake River. The goals of the study were to: (1) field test and evaluate the Single-Release, Modified-Single-Release, and Paired-Release Models for the estimation of survival probabilities through sections of a river and hydroelectric projects; (2) identify operational and logistical constraints to the execution of these models; and (3) determine the usefulness of the models in providing estimates of survival probabilities. Field testing indicated that the numbers of hatchery-reared yearling chinook salmon needed for accurate survival estimates could be collected at differentmore » areas with available gear and methods. For the primary evaluation, seven replicates of 830 to 1,442 hatchery-reared yearling chinook salmon were purse-seined from Lower Granite Reservoir, PIT tagged, and released near Nisqually John boat landing (River Kilometer 726). Secondary releases of PIT-tagged smolts were made at Lower Granite Dam to estimate survival of fish passing through turbines and after detection in the bypass system. Similar secondary releases were made at Little Goose Dam, but with additional releases through the spillway. Based on the success of the 1993 pilot study, the authors believe that the Single-Release and Paired-Release Models will provide accurate estimates of juvenile salmonid passage survival for individual river sections, reservoirs, and hydroelectric projects in the Columbia and Snake Rivers.« less

Measurement of cesium diffusion coefficients in graphite IG-110

NASA Astrophysics Data System (ADS)

Carter, L. M.; Brockman, J. D.; Loyalka, S. K.; Robertson, J. D.

2015-05-01

An understanding of the transport of fission products in High Temperature Gas-Cooled Reactors (HTGRs) is needed for operational safety as well as source term estimations. We have measured diffusion coefficients of Cs in IG-110 by using the release method, wherein we infused small graphite spheres with Cs and measured the release rates using ICP-MS. Diffusion behavior was investigated in the temperature range of 1100-1300 K. We have obtained: DCs = (1.0 ×10-7m2 /s) exp(-1.1/×105J /mol RT) and, compared our results with those available in the literature.

Potential for Water Salvage by Release of the Biocontrol Beetle, Diorhabda carinulata, on Tamarisk (Tamarix ramosissima) Dominated Western U.S. Rivers

NASA Astrophysics Data System (ADS)

Murray, R. S.; Nagler, P. L.; van Riper, C.; Bean, D.; Glenn, E. P.

2009-12-01

The biocontrol beetle, Diorhabda carinulata, has been widely released in the upper basin of the Colorado River to control Tamarisk in the western U.S. A primary motivation for beetle release is to salvage water that would otherwise be lost to transpiration by Tamarisk. We summarize preliminary findings of our assessment of tamarisk, beetle and avian phenology and tamarisk water usage. We used the Enhanced Vegetation Index (EVI) from the MODIS sensors on the Terra satellite to evaluate the prospects for water salvage at 15 riparian release sites in Utah, Colorado, Nevada and Wyoming. EVI was combined with meteorological data to estimate evapotranspiration (ET) at the release sites and in adjacent sites to which the beetle might have spread. ET was estimated at 16-day intervals from 2000 to 2008, encompassing pre-release and post-release periods at each site. Baseline ET rates tended to be low, from 2-6 mm d-1 in summer (less than half of potential ET). At 4 of 15 sites, ET rates estimated by MODIS EVI decreased markedly one to two years after release. At other sites, however, no decrease in ET was detected, and ET tended to recover to pre-release levels at affected sites. Ground observations confirmed that beetles were active at all sites following release, defoliating stands of Tamarisk over areas as large as 200 ha. Along approximately 300 km of the Dolores and Colorado Rivers, ground based monitoring of tamarisk defoliation and refoliation was done using hand held GPS units and GIS software. Monitoring here began at the time beetles entered the system in 2004. Selected sites (15 ha) were also monitored for beetle presence and life stage as well as tamarisk condition. Additional ground data collected at four sites on the Dolores River includes vegetation structure, composition and phenology as well as bird monitoring and productivity. The four sites are dominated by saltcedar, with components of willow and cottonwood. For the last 3 years, monthly monitoring of 100 trees at each site were observed for percent flower and leaf, coupled with ratios of green-to-brown needle observations, done from spring green-up to senescence. Bird census data were collected at 100 m radius circular plot stations (n=20) and birds were captured in mist-nets, in which the type and number of birds were reported as birds per net hour. At each location, the results support our past 3 years of findings for the ET seasonally and annually time-series curves as the beetle came into the area and defoliated saltcedar. This study supports phenological observations showing that beetle damage is spotty and localized at most sites, and reduction in ET is confined mainly to July when beetles are actively feeding. However, beetles are still spreading and the eventual fate of Tamarisk stands remains to be determined.

Estimating the time for dissolution of spent fuel exposed to unlimited water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leider, H.R.; Nguyen, S.N.; Stout, R.B.

1991-12-01

The release of radionuclides from spent fuel cannot be precisely predicted at this point because a satisfactory dissolution model based on specific chemical processes is not yet available. However, preliminary results on the dissolution rate of UO{sub 2} and spent fuel as a function of temperature and water composition have recently been reported. This information, together with data on fragment size distribution of spent fuel, are used to estimate the dissolution response of spent fuel in excess flowing water within the framework of a simple model. In this model, the reaction/dissolution front advances linearly with time and geometry is preserved.more » This also estimates the dissolution rate of the bulk of the fission products and higher actinides, which are uniformly distributed in the UO{sub 2} matrix and are presumed to dissolve congruently. We have used a fuel fragment distribution actually observed to calculate the time for total dissolution of spent fuel. A worst-case estimate was also made using the initial (maximum) rate of dissolution to predict the total dissolution time. The time for total dissolution of centimeter size particles is estimated to be 5.5 {times} 10{sup 4} years at 25{degrees}C.« less

Abuse and Diversion of Immediate Release Opioid Analgesics as Compared to Extended Release Formulations in the United States

PubMed Central

Iwanicki, Janetta L.; Severtson, S. Geoff; McDaniel, Heather; Rosenblum, Andrew; Fong, Chunki; Cicero, Theodore J.; Ellis, Matthew S.; Kurtz, Steven P.; Buttram, Mance E.; Dart, Richard C.

2016-01-01

Background Therapeutic use and abuse of prescription opioids in the United States increased substantially between 1990 and 2010. The Centers for Disease Control estimated deaths related to pharmaceutical opioids reached nearly 19,000 in 2014. Of prescription opioids sold, 10% are extended release (ER) and 90% immediate release (IR). However, most regulations and interventions have focused on decreasing ER abuse. Our objective was to compare rates of abuse and diversion of ER and IR opioid analgesics over time using multiple surveillance programs. Methods Rates of abuse and diversion of ER and IR opioid formulations were compared using data from four surveillance programs in the Researched Abuse, Diversion and Addiction Related Surveillance (RADARS®) System. Data were evaluated from 2009 through 2015, and Poisson regression used to compare IR and ER opioid cases over time. Results From 2009 to 2015, IR opioids were prescribed at a rate 12 to 16 times higher than ER. In the Poison Center Program, population-adjusted rates of Intentional Abuse for IR were 4.6 fold higher than ER opioids (p<0.001). In the Drug Diversion Program, population-adjusted rates of diversion were 6.1 fold higher for IR than ER opioids (p<0.001). In the Opioid Treatment Program, population-adjusted rates of endorsements for abuse were 1.6 fold higher for IR opioids than ER (p = 0.002). In the Survey of Key Informants' Patients Program, population-adjusted rates of endorsements for abuse were 1.5 fold higher for IR opioids than ER (p<0.001). Conclusions Between 2009 and 2015, IR opioids were prescribed at a much higher rate than ER opioids. Results from four surveillance programs show population-adjusted rates of prescription opioid abuse were markedly higher for IR than ER medications. For the greatest public health benefit, future interventions to decrease prescription opioid abuse should focus on both IR and ER formulations. PMID:27936038

Abuse and Diversion of Immediate Release Opioid Analgesics as Compared to Extended Release Formulations in the United States.

PubMed

Iwanicki, Janetta L; Severtson, S Geoff; McDaniel, Heather; Rosenblum, Andrew; Fong, Chunki; Cicero, Theodore J; Ellis, Matthew S; Kurtz, Steven P; Buttram, Mance E; Dart, Richard C

2016-01-01

Therapeutic use and abuse of prescription opioids in the United States increased substantially between 1990 and 2010. The Centers for Disease Control estimated deaths related to pharmaceutical opioids reached nearly 19,000 in 2014. Of prescription opioids sold, 10% are extended release (ER) and 90% immediate release (IR). However, most regulations and interventions have focused on decreasing ER abuse. Our objective was to compare rates of abuse and diversion of ER and IR opioid analgesics over time using multiple surveillance programs. Rates of abuse and diversion of ER and IR opioid formulations were compared using data from four surveillance programs in the Researched Abuse, Diversion and Addiction Related Surveillance (RADARS®) System. Data were evaluated from 2009 through 2015, and Poisson regression used to compare IR and ER opioid cases over time. From 2009 to 2015, IR opioids were prescribed at a rate 12 to 16 times higher than ER. In the Poison Center Program, population-adjusted rates of Intentional Abuse for IR were 4.6 fold higher than ER opioids (p<0.001). In the Drug Diversion Program, population-adjusted rates of diversion were 6.1 fold higher for IR than ER opioids (p<0.001). In the Opioid Treatment Program, population-adjusted rates of endorsements for abuse were 1.6 fold higher for IR opioids than ER (p = 0.002). In the Survey of Key Informants' Patients Program, population-adjusted rates of endorsements for abuse were 1.5 fold higher for IR opioids than ER (p<0.001). Between 2009 and 2015, IR opioids were prescribed at a much higher rate than ER opioids. Results from four surveillance programs show population-adjusted rates of prescription opioid abuse were markedly higher for IR than ER medications. For the greatest public health benefit, future interventions to decrease prescription opioid abuse should focus on both IR and ER formulations.

Intravenous nitroglycerin for controlled cord traction in the management of retained placenta.

PubMed

Visalyaputra, Shusee; Prechapanich, Japarath; Suwanvichai, Sukanya; Yimyam, Suwimol; Permpolprasert, Ladda; Suksopee, Pattipa

2011-02-01

To determine the effect of 200 μg of intravenous nitroglycerin in the release of retained placenta by controlled cord traction. In this randomized controlled study, 40 women with a placenta retained for 30 minutes received intravenously 200 μg of nitroglycerin or a normal saline solution before umbilical cord traction was initiated. The rates of successful removal of the retained placenta in the study (n=20) and control (n=20) groups were compared, as were blood pressure, pulse rate, blood loss, and adverse effects. The placenta was released in only 15% and 20% of the participants in the study and control group, respectively. The remainder of the participants required general anesthesia and manual removal of the retained placenta regardless of group assignation. Blood pressure fell in significantly more women in the study group, but there were no differences in estimated blood loss or minor adverse effects. Intravenously administered nitroglycerin did not facilitate the release of retained placenta by umbilical cord traction. However, cord traction may be performed longer than 30 minutes to attempt releasing the placenta before operative manual removal is initiated. Copyright © 2010 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Emigration of Natural and Hatchery Chinook Salmon and Steelhead Smolts from the Imnaha River, Oregon, Progress Report 2000-2002.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cleary, Peter; Kucera, Paul; Blenden, Michael

This report summarizes the emigration studies of the Nez Perce Tribe in the Imnaha River subbasin during the 2001 and 2002 migration years. A migration year for the Imnaha River is defined here as beginning July 31 of the previous year and ending July 30 the following year. The conclusion of the studies at the end of migration year 2002 marked the 11th year of the Nez Perce Tribe's Lower Snake River Emigration Studies. The Nez Perce Tribe has participated in the Fish Passage Center's Smolt Monitoring Program for nine of the 11 years. These studies collect and tag juvenilemore » chinook salmon and steelhead at two locations in the fall, rkm 74 and rkm 7, and at rkm 7 during the spring. Data from captured and tagged fish provide an evaluation of hatchery production and releases strategies, post release survival of hatchery chinook salmon, abundance of natural chinook salmon, and downstream survival and arrival timing of natural and hatchery chinook salmon and steelhead. The hydrologic conditions that migrating fish encountered in 2001 were characterized as a drought and conditions in 2002 were characterized as below average. Hatchery chinook salmon had a mean fork length that was 34 mm greater in 2001 and 35 mm greater in 2002 than the mean fork length of natural chinook smolts. Hatchery steelhead smolt mean fork lengths were 39 mm greater than natural steelhead smolts in 2001 and 44 mm greater than natural steelhead smolt fork lengths in 2002. A significant difference (p < 0.05) between hatchery and natural chinook salmon and steelhead fork lengths has been documented by these emigration studies from 1997 to 2002. Hatchery chinook salmon were volitionally released in 2001 and 2002 and the 90% arrivals for 2001 and 2002 at the lower rkm 7 trap were within the range of past observations of 22 to 38 days observed in 1999 and 2000. We estimated that 93.9% of the 123,014 hatchery chinook salmon released in 2001 survived to the lower trap and 90.2% of the 303,769 hatchery chinook salmon released in 2002 survived to the lower trap. Post release survival estimates for hatchery chinook salmon were within the range of past estimates; 88.4% in 1998 to 100.9% in 1994. An estimated 7,646 to 23,249 (95% C.I.) natural chinook salmon smolts migrated past the lower Imnaha River trap from April 4 to April 22. An additional 6,767 to 14,706 (95% C.I.) natural chinook salmon smolts migrated past the lower Imnaha River trap from April 23 to May 14, 2002. Natural chinook salmon captured and tagged at the upper rkm 74 trap survived to Lower Granite Dam (LGR) at a rate of 28.8% during migration year 2001 and 21.9% during migration year 2002. The survival estimate for fall tagged natural chinook salmon from the lower trap to LGR was 41.9% in 2001 and 33.3% in 2002. Differences between survival from release to LGR for fall tagged natural chinook salmon from the lower trap have been 5.9% to 16.9% higher than for fall tagged natural chinook salmon from the upper trap from 1994 to 2002. Spring PIT tag release groups of natural chinook salmon, hatchery chinook salmon, and hatchery steelhead produced estimates of survival from the trap to LGR within the range of past estimates since 1993. Estimated survival from release to LGR for 2001 and 2002 were as follows: 83.7% and 86.9% for natural chinook salmon, 80.3% and 77.3% for hatchery chinook salmon, 82.7% and 81.8% for natural steelhead, and 82.0% and 83.0% for hatchery steelhead. Estimates of survival for spring tagged fish from the trap to Lower Monumental Dam (LMO) during the drought of 2001 were the lowest estimates of survival from 1998 to 2002 for natural chinook salmon, and from1997 to 2002 for natural and hatchery steelhead. Estimates of migration year 2001 survival from the trap to LMO were as follows: 65.6% - natural chinook salmon, 68.9% - hatchery chinook salmon, 49.7% natural steelhead, and 42.9% - hatchery steelhead. Estimates of migration year 2002 survival from the trap to LMO were as follows: 76.8% - natural chinook salmon, 68.1% - hatchery chinook salmon, 69.9% natural steelhead, and 78.0% - hatchery steelhead. A smolt-to-adult return rate (SAR) index from LGR to LGR was calculated for migrating pre-smolt and smolt natural chinook salmon, that were PIT tagged in the fall and spring at the lower trap, for brood years 1996 to 1998 (migration years 1998 to 2000). The SARs are representative of in-river Imnaha natural chinook salmon. The LGR to LGR SAR index for presmolt chinook salmon is as follows: 3.08% (BY 1996), 2.41% (BY 1997), and 2.98% (BY 1998). Smolt-to-adult return rate index for spring tagged smolts was lower: 1.75% (BY 1996), 2.24% (BY 1997) and 2.94% (BY 1998). Fall tagged natural chinook salmon from the upper and lower trap and spring tagged natural chinook salmon from the lower trap all had significantly different (p < 0.05) median and cumulative arrival timing at LGR during migration year 2001.« less

TA [2] Continuous, regional methane emissions estimates in northern Pennsylvania gas fields using atmospheric inversions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lauvaux, Thomas

Natural Gas (NG) production activities in the northeastern Marcellus shale have significantly increased in the last decade, possibly releasing large amounts of methane (CH 4) into the atmosphere from the operations at the productions sites and during the processing and transmission steps of the natural gas chain. Based on an intensive aircraft survey, leakage rates from the NG production were quantified in May 2015 and found to be in the order of 0.5% of the total production, higher than reported by the Environmental Protection Agency (EPA) but below the usually observed leakage rates over the shale gases in the US.more » Thanks to the high production rates on average at each well, leakage rates normalized by production appeared to be low in the northeastern Marcellus shale. This result confirms that natural gas production using unconventional techniques in this region is emitting relatively less CH 4 into the atmosphere than other shale reservoirs. The low emissions rate can be explained in part by the high productivity of wells drilled across the northeastern Marcellus region. We demonstrated here that atmospheric monitoring techniques can provide an independent quantification of NG leakage rates using aircraft measurements. The CH 4 analyzers were successfully calibrated at four sites across the region, measuring continuously the atmospheric CH 4 mixing ratios and isotopic 13Ch 4. Our preliminary findings confirm the low leakage rates from tower data collected over September 2015 to November 2016 compared to the aircraft mass-balance estimates in may 2015. However, several episodes revealing large releases of natural gas over several weeks showed that temporal variations in the emissions of CH 4 may increase the actual leakage rate over longer time periods.« less

Survival of hatchery Gulf sturgeon (Acipenser oxyrinchus desotoi Mitchill, 1815) in the Suwannee River, Florida: a 19-year evaluation

USGS Publications Warehouse

Sulak, Kenneth J.; Randall, Michael T.; Clugston, James P.

2014-01-01

An experimental release of 1192 hatchery-reared, individually PIT tagged, 220 days old (296–337 mm TL) Gulf sturgeon, Acipenser oxyrinchus desotoi, was undertaken in 1992 in the Suwannee River, Florida. The original objectives of the 1992 release experiment were to: (1) evaluate survival rate of cultured Gulf sturgeon in the wild vs survival rate of their wild 1992 cohort counterparts, (2) determine the differential effect of release site within the river upon long-term survival, and (3) evaluate comparative growth rates of recaptured hatchery vs captured wild 1992 cohort Gulf sturgeon. The present investigation addressed those original objectives, plus an additional fourth objective: (4) evaluation of hatchery fish recapture rate change over the 19-year experiment. The primary objective was to determine efficacy of potential conservation aquaculture for this species in terms of long-term survival in the wild. Follow-up 1993–2011 gill net sampling in freshwater reaches (rkm 4–237) and the estuarine river mouth (rkm −6 to 4) yielded recaptures representing 13.0% of the total released. Mean annual hatchery fish mortality (including emigration) rate estimated for the 19-year period (1993–2011) was more than twice that for same cohort wild fish. Mark-recapture survival probability (phi) for hatchery fish, 1993–2011, was substantially lower (0.733) than for their wild counterparts (0.888). Mean annual hatchery fish recapture rate, as a percentage of all 1992 cohort fish recaptures, declined significantly after age-7, coinciding with age of onset of migration into the open Gulf of Mexico. Hypothesized causal factors may be differentially lower fitness in the marine habitat or permanent outmigration due to natal river imprinting failure. Hatchery fish recapture rates varied significantly for fish from the ten release sites, being highest near the river mouth, and lowest for the furthest upriver sites in the Suwannee River and its Santa Fe River tributary. Hatchery fish also displayed a significantly lower growth rate than their wild counterparts through age 3000 days. Cumulative hatchery fish mortality of 99.87% over 19 years predicts <3 individuals would have survived through 2011. From the results of the 1992 release experiment, hatchery supplementation as a Gulf sturgeon conservation measure does not appear to be an effective option.

ESTIMATION OF EFFECTIVE DOSE FROM EXTERNAL EXPOSURE DUE TO SHORT-LIVED NUCLIDES IN THE PREFECTURES SURROUNDING FUKUSHIMA.

PubMed

Miyatake, Hirokazu; Yoshizawa, Nobuaki; Suzuki, Gen

2018-05-11

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in a release of radionuclides into the environment. Since the accident, measurements of radiation in the environment such as air dose rate and deposition density of radionuclides have been performed by various organizations and universities. In particular, Japan Atomic Energy Agency (JAEA) has been performing observations of air dose rate using a car-borne survey system continuously over widespread areas. Based on the data measured by JAEA, we estimated effective dose from external exposure in the prefectures surrounding Fukushima. Since car-borne survey started a few months after the accident, the main contribution to measured data comes from 137Cs and 134Cs whose half-lives are relatively long. Using air dose rate of 137Cs and 134Cs and the ratio of deposition density of short-lived nuclides to that of 137Cs and 134Cs, we also estimated contributions to the effective dose from other short-lived nuclides.

Rapid dissolution of propofol emulsions under sink conditions.

PubMed

Damitz, Robert; Chauhan, Anuj

2015-03-15

Pain accompanying intravenous injections of propofol is a major problem in anesthesia. Pain is ascribed to the interaction of propofol with the local vasculature and could be impacted by rapid dissolution of the emulsion formulation to release the drug. In this paper, we measure the dissolution of propofol emulsions including the commercial formulation Diprivan(®). We image the turbidity of blood protein sink solutions after emulsions are injected. The images are digitized, and the drug release times are estimated from the pixel intensity data for a range of starting emulsion droplet size. Drug release times are compared to a mechanistic model. After injection, pixel intensity or turbidity decreases due to reductions in emulsion droplet size. Drug release times can still be measured even if the emulsion does not completely dissolve such as with Diprivan(®). Both pure propofol emulsions and Diprivan(®) release drug very rapidly (under five seconds). Reducing emulsion droplet size significantly increases the drug release rate. Drug release times observed are slightly longer than the model prediction likely due to imperfect mixing. Drug release from emulsions occurs very rapidly after injection. This could be a contributing factor to pain on injection of propofol emulsions. Copyright © 2015. Published by Elsevier B.V.

Prediction of error rates in dose-imprinted memories on board CRRES by two different methods. [Combined Release and Radiation Effects Satellite

NASA Technical Reports Server (NTRS)

Brucker, G. J.; Stassinopoulos, E. G.

1991-01-01

An analysis of the expected space radiation effects on the single event upset (SEU) properties of CMOS/bulk memories onboard the Combined Release and Radiation Effects Satellite (CRRES) is presented. Dose-imprint data from ground test irradiations of identical devices are applied to the predictions of cosmic-ray-induced space upset rates in the memories onboard the spacecraft. The calculations take into account the effect of total dose on the SEU sensitivity of the devices as the dose accumulates in orbit. Estimates of error rates, which involved an arbitrary selection of a single pair of threshold linear energy transfer (LET) and asymptotic cross-section values, were compared to the results of an integration over the cross-section curves versus LET. The integration gave lower upset rates than the use of the selected values of the SEU parameters. Since the integration approach is more accurate and eliminates the need for an arbitrary definition of threshold LET and asymptotic cross section, it is recommended for all error rate predictions where experimental sigma-versus-LET curves are available.

University Eligibility: Are Locally Reported Figures Comparable to the Commission's Estimates? Factsheet 06-03

ERIC Educational Resources Information Center

California Postsecondary Education Commission, 2006

2006-01-01

The Commission periodically releases university eligibility rates for California high school graduates. These figures, which are based on a review of transcripts collected from schools, show the percentage of high school graduates who meet the admission requirements of the University of California (UC) and the California State University (CSU).…

Sediment transport primer: estimating bed-material transport in gravel-bed rivers

Treesearch

Peter Wilcock; John Pitlick; Yantao Cui

2009-01-01

This primer accompanies the release of BAGS, software developed to calculate sediment transport rate in gravel-bed rivers. BAGS and other programs facilitate calculation and can reduce some errors, but cannot ensure that calculations are accurate or relevant. This primer was written to help the software user define relevant and tractable problems, select appropriate...

Some Environmental Consequences of a Release of Ethanol to Ground Water

EPA Science Inventory

Estimates on the concentration of ethanol in ground water as a result of a spill of gasoline containing 10% to 15% ethanol vary from approximately 4,000 mg/L to 15,000 mg/L. Published data on the rate of ethanol biodegradation vary from 2 mg/L per day to greater than 500 mg/L ...

Insights into accelerated liposomal release of topotecan in plasma monitored by a non-invasive fluorescence spectroscopic method

PubMed Central

Fugit, Kyle D.; Jyoti, Amar; Upreti, Meenakshi; Anderson, Bradley D.

2014-01-01

A non-invasive fluorescence method was developed to monitor liposomal release kinetics of the anticancer agent topotecan (TPT) in physiological fluids and subsequently used to explore the cause of accelerated release in plasma. Analyses of fluorescence excitation spectra confirmed that unencapsulated TPT exhibits a red shift in its spectrum as pH is increased. This property was used to monitor TPT release from actively loaded liposomal formulations having a low intravesicular pH. Mathematical release models were developed to extract reliable rate constants for TPT release in aqueous solutions monitored by fluorescence and release kinetics obtained by HPLC. Using the fluorescence method, accelerated TPT release was observed in plasma as previously reported in the literature. Simulations to estimate the intravesicular pH were conducted to demonstrate that accelerated release correlated with alterations in the low intravesicular pH. This was attributed to the presence of ammonia in plasma samples rather than proteins and other plasma components generally believed to alter release kinetics in physiological samples. These findings shed light on the critical role that ammonia may play in contributing to the preclinical/clinical variability and performance seen with actively-loaded liposomal formulations of TPT and other weakly-basic anticancer agents. PMID:25456833

River fluxes to the sea from the ocean's 10Be/9Be ratio

NASA Astrophysics Data System (ADS)

von Blanckenburg, F.; Bouchez, J.

2013-12-01

The ratio of the meteoric cosmogenic radionuclide 10Be to the stable isotope 9Be is proposed here to be a flux proxy of terrigenous input into the oceans. The ocean's dissolved 10Be/9Be is set by (1) the flux of meteoric 10Be produced in the atmosphere; (2) the denudational flux of the rivers discharging into a given ocean basin; (3) the fraction of 9Be that is released from primary minerals during weathering (meaning the 9Be transported by rivers in either the dissolved form or adsorbed onto sedimentary particles and incorporated into secondary oxides); and (4) the fraction of riverine 10Be and 9Be actually released into seawater. Using published 10Be/9Be data of rivers for which independent denudation rate estimates exist we first find that the global average fraction of 9Be released during weathering into river waters and their particulate load is 20% and does not depend on denudation rate. We then evaluate this quantitative denudation rate proxy by using published dissolved seawater Be isotope data and a compilation of global river loads (15Gt/yr). We find that the measured global average oceanic dissolved 10Be/9Be ratio of about 0.9E-7 is satisfied by the mass balance if only 6.5% of the dissolved and reactive riverine Be is eventually released to the open ocean by boundary exchange. Except for the South Atlantic and the South Pacific, in which the 10Be/9Be ratio is dominated by Be advected through ocean circulation, good agreement results between 10Be/9Be ratios predicted by denudation rates and measured ocean 10Be/9Be ratios when we establish this mass balance for individual ocean basins. As the seawater 10Be/9Be ratio is faithfully recorded in marine chemical precipitates the 10Be/9Be ratio extracted from authigenic sediments can now serve to estimate relative changes in terrigenous input into the oceans back through time on a global and on a basin scale.

Re-analysis of a banding study to test the effects of an experimental increase in bag limits of mourning doves

USGS Publications Warehouse

Otis, D.L.; White, Gary C.

2002-01-01

In 1966-1971, eastern US states with hunting seasons on mourning doves (Zenaida macroura) participated in a study designed to estimate the effects of bag limit increases on population survival rates. More than 400 000 adult and juvenile birds were banded and released during this period, and subsequent harvest and return of bands, together with total harvest estimates from mail and telephone surveys of hunters, provided the database for analysis. The original analysis used an ANOVA framework, and resulted in inferences of no effect of bag limit increase on population parameters (Hayne 1975). We used a logistic regression analysis to infer that the bag limit increase did not cause a biologically significant increase in harvest rate and thus the experiment could not provide any insight into the relationship between harvest and annual survival rates. Harvest rate estimates of breeding populations from geographical subregions were used as covariates in a Program MARK analysis and revealed an association between annual survival and harvest rates, although this relationship is potentially confounded by a latitudinal gradient in survival rates of dove populations. We discuss methodological problems encountered in the analysis of these data, and provide recommendations for future studies of the relationship between harvest and annual survival rates of mourning dove populations.

Inverse modelling of radionuclide release rates using gamma dose rate observations

NASA Astrophysics Data System (ADS)

Hamburger, Thomas; Stohl, Andreas; von Haustein, Christoph; Thummerer, Severin; Wallner, Christian

2014-05-01

Severe accidents in nuclear power plants such as the historical accident in Chernobyl 1986 or the more recent disaster in the Fukushima Dai-ichi nuclear power plant in 2011 have drastic impacts on the population and environment. The hazardous consequences reach out on a national and continental scale. Environmental measurements and methods to model the transport and dispersion of the released radionuclides serve as a platform to assess the regional impact of nuclear accidents - both, for research purposes and, more important, to determine the immediate threat to the population. However, the assessments of the regional radionuclide activity concentrations and the individual exposure to radiation dose underlie several uncertainties. For example, the accurate model representation of wet and dry deposition. One of the most significant uncertainty, however, results from the estimation of the source term. That is, the time dependent quantification of the released spectrum of radionuclides during the course of the nuclear accident. The quantification of the source terms of severe nuclear accidents may either remain uncertain (e.g. Chernobyl, Devell et al., 1995) or rely on rather rough estimates of released key radionuclides given by the operators. Precise measurements are mostly missing due to practical limitations during the accident. Inverse modelling can be used to realise a feasible estimation of the source term (Davoine and Bocquet, 2007). Existing point measurements of radionuclide activity concentrations are therefore combined with atmospheric transport models. The release rates of radionuclides at the accident site are then obtained by improving the agreement between the modelled and observed concentrations (Stohl et al., 2012). The accuracy of the method and hence of the resulting source term depends amongst others on the availability, reliability and the resolution in time and space of the observations. Radionuclide activity concentrations are observed on a relatively sparse grid and the temporal resolution of available data may be low within the order of hours or a day. Gamma dose rates on the other hand are observed routinely on a much denser grid and higher temporal resolution. Gamma dose rate measurements contain no explicit information on the observed spectrum of radionuclides and have to be interpreted carefully. Nevertheless, they provide valuable information for the inverse evaluation of the source term due to their availability (Saunier et al., 2013). We present a new inversion approach combining an atmospheric dispersion model and observations of radionuclide activity concentrations and gamma dose rates to obtain the source term of radionuclides. We use the Lagrangian particle dispersion model FLEXPART (Stohl et al., 1998; Stohl et al., 2005) to model the atmospheric transport of the released radionuclides. The gamma dose rates are calculated from the modelled activity concentrations. The inversion method uses a Bayesian formulation considering uncertainties for the a priori source term and the observations (Eckhardt et al., 2008). The a priori information on the source term is a first guess. The gamma dose rate observations will be used with inverse modelling to improve this first guess and to retrieve a reliable source term. The details of this method will be presented at the conference. This work is funded by the Bundesamt für Strahlenschutz BfS, Forschungsvorhaben 3612S60026. References Davoine, X. and Bocquet, M., Atmos. Chem. Phys., 7, 1549-1564, 2007. Devell, L., et al., OCDE/GD(96)12, 1995. Eckhardt, S., et al., Atmos. Chem. Phys., 8, 3881-3897, 2008. Saunier, O., et al., Atmos. Chem. Phys., 13, 11403-11421, 2013. Stohl, A., et al., Atmos. Environ., 32, 4245-4264, 1998. Stohl, A., et al., Atmos. Chem. Phys., 5, 2461-2474, 2005. Stohl, A., et al., Atmos. Chem. Phys., 12, 2313-2343, 2012.

Tire-wear particles as a source of zinc to the environment

USGS Publications Warehouse

Councell, T.B.; Duckenfield, K.U.; Landa, E.R.; Callender, E.

2004-01-01

Tire-tread material has a zinc (Zn) content of about 1 wt %. The quantity of tread material lost to road surfaces by abrasion has not been well characterized. Two approaches were used to assess the magnitude of this nonpoint source of Zn in the U.S. for the period 1936-1999. In the first approach, tread-wear rates from the automotive engineering literature were used in conjunction with vehicle distance-driven data from the U.S. Department of Transportation to determine Zn releases. A second approach calculated this source term from the volume of tread lost during lifetime tire wear. These analyses showed that the quantity of Zn released by tire wear in the mid-1990s was of the same magnitude as that released from waste incineration. For 1999, the quantity of Zn released by tire wear in the U.S. is estimated to be 10 000-11 000 metric tons. A specific case study focused on Zn sources and sinks in an urban-suburban watershed (Lake Anne) in the Washington, DC, metropolitan area for a time period of the late 1990s. The atmospheric flux of total Zn (wet deposition) to the watershed was 2 ??g/cm2/yr. The flux of Zn to the watershed estimated from tire wear was 42 ??g/cm2/yr. The measured accumulation rate of total Zn in age-dated sediment cores from Lake Anne was 27 ??g/cm2/yr. These data suggest that tire-wear Zn inputs to urban-suburban watersheds can be significantly greater than atmospheric inputs, although the watershed appears to retain appreciable quantities of vehicular Zn inputs.

Gradient anaysis of biomass in Costa Rica and a first estimate of total emissions of greenhouse gases from biomass burning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helmer, E.H.; Brown, S.

One important component of sustainable development for a nation is the degree to which it can balance greenhouse gas (GHG) exchange with the atmosphere. Scientists at NHEERL-WED recently estimated the release of such GHGs from the conversion of a range of forest types in Costa Rica between 1940-1983. They also evaluated the influence of environmental gradients that affect the rates and patterns of deforestation and the carbon pools of the forest cleared on GHG emissions.

Survival of female northern pintails wintering in southwestern Louisiana

USGS Publications Warehouse

Cox, R.R.; Afton, A.D.; Pace, R. M.

1998-01-01

The North American breeding population of northern pintails (Anas acuta) has reached previously unprecedented low numbers 4 times since 1983. Because pintails show high fidelity to wintering areas, regional survival estimates and identification of factors influencing survival are needed to guide management of wintering pintails. We used raidiotelemetry to estimate survival rates of female pintails wintering in southwestern Lousiaina. We tested for variation in survival and hunting mortality rates in realtiaon to age (immature or adult), winter (1990-91, 1991-92, 1992-93), time period (prehunting season, first hunting season, time between split hunting seasons, second hunting season, posthunting season), body condition (body mass when released, adjusted for body size), and region (southwestern Louisiana or elsewhere on the Texas-Louisiana Gulf Coast or Mississippi Alluvial Valley).

Tracing oxidative weathering from the Andes to the lowland Amazon Basin using dissoved rhenium

NASA Astrophysics Data System (ADS)

Dellinger, M.; Hilton, R. G.; West, A. J.; Torres, M.; Burton, K. W.; Clark, K. E.; Baronas, J. J.

2016-12-01

Over long timescales (>105 yrs), the abundance of carbon dioxide (CO2) in the atmosphere is determined by the balance of the major carbon sources and sinks. Among the major carbon sources, the oxidation of organic carbon contained within sedimentary rocks ("petrogenic" carbon, or OCpetro) is thought to result in CO2 emission of similar magnitude to that released by volcanism. Rhenium (Re) has been proposed as a proxy for tracing OCpetro oxidation. Here we investigate the source, behavior and flux of dissolved and particulate rhenium (Re) in the Madre de Dios watershed (a major Andean tributary of the Amazon River) and the lowlands, aiming to characterize the behavior of Re in river water and quantify the flux of CO2 released by OCpetro oxidation. Measured Re concentrations in Andean rivers range from 0.07 to 1.55 ppt. In the Andes, Re concentration do not change significantly with water discharge, whereas in the lowlands, Re concentration decrease at high water discharge. Mass balance calculation show that more than 70% of the dissolved Re is sourced from the oxidation of OCpetro the Andes-floodplain system. We calculate dissolved Re flux over a hydrological year to estimate the rates of oxidative weathering, and the associated CO2 release from OCpetro. Rates are high in the Andean headwaters, consistent with estimates from other mountain rivers with similar rates of physical erosion. We find evidence that a significant amount of additional oxidation (Re flux) happens during floodplain transport. These results have important implications for improving our understanding of the source and processes controlling Re in rivers, and allowing us to quantify long-term OCpetro cycling in large river basins.

Lake Roosevelt Fisheries Evaluation Program : Lake Whatcom Kokanee Salmon (Oncorhynchus nerka kennerlyi) : Investigations in Lake Roosevelt Annual Report 1999-2000.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McLellan, Holly J.; Scholz, Allan T.; McLellan, Jason G.

2001-07-01

Lake Whatcom stock kokanee have been planted in Lake Roosevelt since 1988 with the primary goal of establishing a self-sustaining fishery. Returns of hatchery kokanee to egg collection facilities and recruitment to the creel have been minimal. Therefore, four experiments were conducted to determine the most appropriate release strategy that would increase kokanee returns. The first experiment compared morpholine and non-morpholine imprinted kokanee return rates, the second experiment compared early and middle run Whatcom kokanee, the third experiment compared early and late release dates, and the fourth experiment compared three net pen release strategies: Sherman Creek hatchery vs. Sherman Creekmore » net pens, Colville River net pens vs. Sherman Creek net pens, and upper vs. lower reservoir net pen releases. Each experiment was tested in three ways: (1) returns to Sherman Creek, (2) returns to other tributaries throughout the reservoir, and (3) returns to the creel. Chi-square analysis of hatchery and tributary returns indicated no significant difference between morpholine imprinted and non-imprinted fish, early run fish outperformed middle run fish, early release date outperformed late release fish, and the hatchery outperformed all net pen releases. Hatchery kokanee harvest was estimated at 3,323 fish, which was 33% of the total harvest. Return rates (1998 = 0.52%) of Whatcom kokanee were low indicating an overall low performance that could be caused by high entrainment, predation, and precocity. A kokanee stock native to the upper Columbia, as opposed to the coastal Whatcom stock, may perform better in Lake Roosevelt.« less

Substance use disorders, psychiatric disorders, and mortality after release from prison: a nationwide longitudinal cohort study

PubMed Central

Chang, Zheng; Lichtenstein, Paul; Larsson, Henrik; Fazel, Seena

2015-01-01

Summary Background High mortality rates have been reported in people released from prison compared with the general population. However, few studies have investigated potential risk factors associated with these high rates, especially psychiatric determinants. We aimed to investigate the association between psychiatric disorders and mortality in people released from prison in Sweden. Methods We studied all people who were imprisoned since Jan 1, 2000, and released before Dec 31, 2009, in Sweden for risks of all-cause and external-cause (accidents, suicide, homicide) mortality after prison release. We obtained data for substance use disorders and other psychiatric disorders, and criminological and sociodemographic factors from population-based registers. We calculated hazard ratios (HRs) by Cox regression, and then used them to calculate population attributable fractions for post-release mortality. To control for potential familial confounding, we compared individuals in the study with siblings who were also released from prison, but without psychiatric disorders. We tested whether any independent risk factors improved the prediction of mortality beyond age, sex, and criminal history. Findings We identified 47 326 individuals who were imprisoned. During a median follow-up time of 5·1 years (IQR 2·6–7·5), we recorded 2874 (6%) deaths after release from prison. The overall all-cause mortality rate was 1205 deaths per 100 000 person-years. Substance use disorders significantly increased the rate of all-cause mortality (alcohol use: adjusted HR 1·62, 95% CI 1·48–1·77; drug use: 1·67, 1·53–1·83), and the association was independent of sociodemographic, criminological, and familial factors. We identified no strong evidence that other psychiatric disorders increased mortality after we controlled for potential confounders. In people released from prison, 925 (34%) of all-cause deaths in men and 85 (50%) in women were potentially attributable to substance use disorders. Substance use disorders were also an independent determinant of external-cause mortality, with population attributable fraction estimates at 42% in men and 70% in women. Substance use disorders significantly improved the prediction of external-cause mortality, in addition to sociodemographic and criminological factors. Interpretation Interventions to address substance use disorders could substantially decrease the burden of excess mortality in people released from prison, but might need to be provided beyond the immediate period after release. Funding Wellcome Trust, Swedish Research Council, and the Swedish Research Council for Health, Working Life and Welfare. PMID:26360286

Simulation of the hydrodynamic conditions of the eye to better reproduce the drug release from hydrogel contact lenses: experiments and modeling.

PubMed

Pimenta, A F R; Valente, A; Pereira, J M C; Pereira, J C F; Filipe, H P; Mata, J L G; Colaço, R; Saramago, B; Serro, A P

2016-12-01

Currently, most in vitro drug release studies for ophthalmic applications are carried out in static sink conditions. Although this procedure is simple and useful to make comparative studies, it does not describe adequately the drug release kinetics in the eye, considering the small tear volume and flow rates found in vivo. In this work, a microfluidic cell was designed and used to mimic the continuous, volumetric flow rate of tear fluid and its low volume. The suitable operation of the cell, in terms of uniformity and symmetry of flux, was proved using a numerical model based in the Navier-Stokes and continuity equations. The release profile of a model system (a hydroxyethyl methacrylate-based hydrogel (HEMA/PVP) for soft contact lenses (SCLs) loaded with diclofenac) obtained with the microfluidic cell was compared with that obtained in static conditions, showing that the kinetics of release in dynamic conditions is slower. The application of the numerical model demonstrated that the designed cell can be used to simulate the drug release in the whole range of the human eye tear film volume and allowed to estimate the drug concentration in the volume of liquid in direct contact with the hydrogel. The knowledge of this concentration, which is significantly different from that measured in the experimental tests during the first hours of release, is critical to predict the toxicity of the drug release system and its in vivo efficacy. In conclusion, the use of the microfluidic cell in conjunction with the numerical model shall be a valuable tool to design and optimize new therapeutic drug-loaded SCLs.

THE ENVIRONMENTAL CONSEQUENCES OF A RELEASE OF ETHANOL TO GROUND WATER-POSTER PRESENTATION

EPA Science Inventory

Estimates on the concentration of ethanol in ground water as a result of a spill of gasoline containing 10% to 15% ethanol vary from approximately 4,000 mg/L to 15,000 mg/L. Published data on the rate of ethanol biodegradation vary from 2.6 mg/L per day to greater than 500 mg/...

Mobile sensing of point-source fugitive methane emissions using Bayesian inference: the determination of the likelihood function

NASA Astrophysics Data System (ADS)

Zhou, X.; Albertson, J. D.

2016-12-01

Natural gas is considered as a bridge fuel towards clean energy due to its potential lower greenhouse gas emission comparing with other fossil fuels. Despite numerous efforts, an efficient and cost-effective approach to monitor fugitive methane emissions along the natural gas production-supply chain has not been developed yet. Recently, mobile methane measurement has been introduced which applies a Bayesian approach to probabilistically infer methane emission rates and update estimates recursively when new measurements become available. However, the likelihood function, especially the error term which determines the shape of the estimate uncertainty, is not rigorously defined and evaluated with field data. To address this issue, we performed a series of near-source (< 30 m) controlled methane release experiments using a specialized vehicle mounted with fast response methane analyzers and a GPS unit. Methane concentrations were measured at two different heights along mobile traversals downwind of the sources, and concurrent wind and temperature data are recorded by nearby 3-D sonic anemometers. With known methane release rates, the measurements were used to determine the functional form and the parameterization of the likelihood function in the Bayesian inference scheme under different meteorological conditions.

Bounding the moment deficit rate on crustal faults using geodetic data: Methods

DOE PAGES

Maurer, Jeremy; Segall, Paul; Bradley, Andrew Michael

2017-08-19

Here, the geodetically derived interseismic moment deficit rate (MDR) provides a first-order constraint on earthquake potential and can play an important role in seismic hazard assessment, but quantifying uncertainty in MDR is a challenging problem that has not been fully addressed. We establish criteria for reliable MDR estimators, evaluate existing methods for determining the probability density of MDR, and propose and evaluate new methods. Geodetic measurements moderately far from the fault provide tighter constraints on MDR than those nearby. Previously used methods can fail catastrophically under predictable circumstances. The bootstrap method works well with strong data constraints on MDR, butmore » can be strongly biased when network geometry is poor. We propose two new methods: the Constrained Optimization Bounding Estimator (COBE) assumes uniform priors on slip rate (from geologic information) and MDR, and can be shown through synthetic tests to be a useful, albeit conservative estimator; the Constrained Optimization Bounding Linear Estimator (COBLE) is the corresponding linear estimator with Gaussian priors rather than point-wise bounds on slip rates. COBE matches COBLE with strong data constraints on MDR. We compare results from COBE and COBLE to previously published results for the interseismic MDR at Parkfield, on the San Andreas Fault, and find similar results; thus, the apparent discrepancy between MDR and the total moment release (seismic and afterslip) in the 2004 Parkfield earthquake remains.« less

Bounding the moment deficit rate on crustal faults using geodetic data: Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maurer, Jeremy; Segall, Paul; Bradley, Andrew Michael

Here, the geodetically derived interseismic moment deficit rate (MDR) provides a first-order constraint on earthquake potential and can play an important role in seismic hazard assessment, but quantifying uncertainty in MDR is a challenging problem that has not been fully addressed. We establish criteria for reliable MDR estimators, evaluate existing methods for determining the probability density of MDR, and propose and evaluate new methods. Geodetic measurements moderately far from the fault provide tighter constraints on MDR than those nearby. Previously used methods can fail catastrophically under predictable circumstances. The bootstrap method works well with strong data constraints on MDR, butmore » can be strongly biased when network geometry is poor. We propose two new methods: the Constrained Optimization Bounding Estimator (COBE) assumes uniform priors on slip rate (from geologic information) and MDR, and can be shown through synthetic tests to be a useful, albeit conservative estimator; the Constrained Optimization Bounding Linear Estimator (COBLE) is the corresponding linear estimator with Gaussian priors rather than point-wise bounds on slip rates. COBE matches COBLE with strong data constraints on MDR. We compare results from COBE and COBLE to previously published results for the interseismic MDR at Parkfield, on the San Andreas Fault, and find similar results; thus, the apparent discrepancy between MDR and the total moment release (seismic and afterslip) in the 2004 Parkfield earthquake remains.« less

Refinement and evaluation of the Massachusetts firm-yield estimator model version 2.0

USGS Publications Warehouse

Levin, Sara B.; Archfield, Stacey A.; Massey, Andrew J.

2011-01-01

The firm yield is the maximum average daily withdrawal that can be extracted from a reservoir without risk of failure during an extended drought period. Previously developed procedures for determining the firm yield of a reservoir were refined and applied to 38 reservoir systems in Massachusetts, including 25 single- and multiple-reservoir systems that were examined during previous studies and 13 additional reservoir systems. Changes to the firm-yield model include refinements to the simulation methods and input data, as well as the addition of several scenario-testing capabilities. The simulation procedure was adapted to run at a daily time step over a 44-year simulation period, and daily streamflow and meteorological data were compiled for all the reservoirs for input to the model. Another change to the model-simulation methods is the adjustment of the scaling factor used in estimating groundwater contributions to the reservoir. The scaling factor is used to convert the daily groundwater-flow rate into a volume by multiplying the rate by the length of reservoir shoreline that is hydrologically connected to the aquifer. Previous firm-yield analyses used a constant scaling factor that was estimated from the reservoir surface area at full pool. The use of a constant scaling factor caused groundwater flows during periods when the reservoir stage was very low to be overestimated. The constant groundwater scaling factor used in previous analyses was replaced with a variable scaling factor that is based on daily reservoir stage. This change reduced instability in the groundwater-flow algorithms and produced more realistic groundwater-flow contributions during periods of low storage. Uncertainty in the firm-yield model arises from many sources, including errors in input data. The sensitivity of the model to uncertainty in streamflow input data and uncertainty in the stage-storage relation was examined. A series of Monte Carlo simulations were performed on 22 reservoirs to assess the sensitivity of firm-yield estimates to errors in daily-streamflow input data. Results of the Monte Carlo simulations indicate that underestimation in the lowest stream inflows can cause firm yields to be underestimated by an average of 1 to 10 percent. Errors in the stage-storage relation can arise when the point density of bathymetric survey measurements is too low. Existing bathymetric surfaces were resampled using hypothetical transects of varying patterns and point densities in order to quantify the uncertainty in stage-storage relations. Reservoir-volume calculations and resulting firm yields were accurate to within 5 percent when point densities were greater than 20 points per acre of reservoir surface. Methods for incorporating summer water-demand-reduction scenarios into the firm-yield model were developed as well as the ability to relax the no-fail reliability criterion. Although the original firm-yield model allowed monthly reservoir releases to be specified, there have been no previous studies examining the feasibility of controlled releases for downstream flows from Massachusetts reservoirs. Two controlled-release scenarios were tested—with and without a summer water-demand-reduction scenario—for a scenario with a no-fail criterion and a scenario that allows for a 1-percent failure rate over the entire simulation period. Based on these scenarios, about one-third of the reservoir systems were able to support the flow-release scenarios at their 2000–2004 usage rates. Reservoirs with higher storage ratios (reservoir storage capacity to mean annual streamflow) and lower demand ratios (mean annual water demand to annual firm yield) were capable of higher downstream release rates. For the purposes of this research, all reservoir systems were assumed to have structures which enable controlled releases, although this assumption may not be true for many of the reservoirs studied.

Satellite-observed latent heat release in a tropical cyclone

NASA Technical Reports Server (NTRS)

Adler, R. F.; Rodgers, E. B.

1976-01-01

Earlier observational estimates of storm latent heat release (LHR) have been made using a moisture budget approach. The present paper summarizes results for the tropical cyclone Nora, using the electrically scanning microwave radiometer (ESMR) on Nimbus 5, on the basis of the theoretical brightness temperature/rainfall rate relationship for an assumed freezing level of 5 km. The LHR of the storm as a function of time for a circular area of radius 4 deg latitude positioned on the circulation center is discussed along with the calculated mean rain rate as a function of distance from the storm center. The contribution of the various magnitudes of rain rates to the total LHR of the storm is examined. It is concluded that the Nimbus 5 ESMR data can be used to determine the LHR characteristics of tropical cyclones and are potentially useful in the monitoring of such storms. The calculations for Typhoon Nora indicate that the LHR for the storm increases as the storm intensifies from a tropical disturbance to a typhoon.

Estimation of Effective Dose from External Exposure in The Six Prefectures adjacent to Fukushima Prefecture

NASA Astrophysics Data System (ADS)

Miyatake, Hirokazu; Yoshizawa, Nobuaki; Hirakawa, Sachiko; Murakami, Kana; Takizawa, Mari; Kawai, Masaki; Sato, Osamu; Takagi, Shunji; Suzuki, Gen

2017-09-01

The Fukushima Daiichi Nuclear Power Plant accident caused a release of radionuclides. Radionuclides were deposited on the ground not only in Fukushima prefecture but also in nearby prefectures. Since the accident, measurement of radiation in environment such as air dose rate and deposition density of radionuclides has been performed by many organizations and universities. In particular, Japan Atomic Energy Agency (JAEA) has been performing observations of air dose rate using a car-borne survey system continuously and over wide areas. In our study, using the data measured by JAEA, we estimated effective dose from external exposure in the six prefectures adjacent to Fukushima prefecture. Since car-borne survey was started a few months later after the accident, measured air dose rate in this method is mainly contributed by 137Cs and 134Cs whose half-lives are relatively long. Therefore, based on air dose rate of 137Cs and 134Cs and the ratio of deposition density of short-half-life nuclides to that of 137Cs and 134Cs, we also estimated effective dose contributed from not only 137Cs and 134Cs but also other short-half-life nuclides. We compared the effective dose estimated by the method above with that of UNSCEAR and measured data using personal dosimeters in some areas.

Rhenium Concentration Variations in the Non-flood Period of the Yangtze River Water and Estimation of the Oxidation Rate of Organic Carbon

NASA Astrophysics Data System (ADS)

Xu, P.; Chen, Y.; Li, S.; Wang, K.

2017-12-01

In geological history, the uplift of the Tibet plateau has accelerated the silicate weathering and organic carbon burial at the same time, which made great influence on the global carbon cycle by increasing the carbon sink. Because of the vital connection between tectonic uplift and carbon cycle, more and more attention was casted on rivers originating from orogens. The Yangtze River, as an important large river in the world, is one of them. However, although silicate weathering has been studied thoroughly, researches on organic carbon cycle are much less, and oxidation of fossil organic carbon remained poorly constrained. In this study, we try to use rhenium(Re) as a proxy to estimate the oxidation rate of fossil organic carbon and thus proceed our understanding towards the carbon cycle, the silicate weathering. This is because Re has a close relationship with organic carbon in the sediments and will be released into hydrological network in the mountain river catchments by being oxidized and exist as soluble ReO4-, so that we can use Re concentration in river water to estimate the oxidation rate of organic carbon. We collected water samples from the Yangtze River fortnightly at Banqiao Ferry and the sampling date cover the non-flood period. In this way, we are able to have a rough estimate of the amount of carbon dioxide that released to the atmosphere by the oxidation of organic carbon, using the data of non-flood period we got. We found that Re concentration in Yangtze River ranges approximately from 45 to 85 pmol/L. The rate of organic carbon weathering is estimated using the expression, ΦCO2,fossil=[Re]×runoff×[OC/Re]rock, and according to researches on the black shale of Yangtze River, the value 2.86×106 is chosen as the ratio OC(organic carbon) to Re in the black shale. The result is a really high flux, up to 152×109mol/y, just a little less than of the CO2 consumption rates from silicate weathering which is 191×109mol/y and about 166×109mol/y in non-flood period. Our result indicates that in the Yangtze Basin, oxidation of fossil organic carbon can very likely offset the carbon dioxide that removed by silicate weathering.

Urban Pollutant Transport and Infiltration into Buildings Using Perfluorocarbon Tracers.

PubMed

Matthews, James C; Bacak, Asan; Khan, M Anwar H; Wright, Matthew D; Priestley, Michael; Martin, Damien; Percival, Carl J; Shallcross, Dudley E

2017-02-21

People spend the majority of their time indoors and therefore the quality of indoor air is worthy of investigation; indoor air quality is affected by indoor sources of pollutants and from pollutants entering buildings from outdoors. In this study, unique perfluorocarbon tracers were released in five experiments at a 100 m and ~2 km distance from a large university building in Manchester, UK and tracer was also released inside the building to measure the amount of outdoor material penetrating into buildings and the flow of material within the building itself. Air samples of the tracer were taken in several rooms within the building, and a CO₂ tracer was used within the building to estimate air-exchange rates. Air-exchange rates were found to vary between 0.57 and 10.90 per hour. Indoor perfluorocarbon tracer concentrations were paired to outdoor tracer concentrations, and in-out ratios were found to vary between 0.01 and 3.6. The largest room with the lowest air-exchange rate exhibited elevated tracer concentrations for over 60 min after the release had finished, but generally had the lowest concentrations, the room with the highest ventilation rates had the highest concentration over 30 min, but the peak decayed more rapidly. Tracer concentrations indoors compared to outdoors imply that pollutants remain within buildings after they have cleared outside, which must be considered when evaluating human exposure to outdoor pollutants.

Urban Pollutant Transport and Infiltration into Buildings Using Perfluorocarbon Tracers

PubMed Central

Matthews, James C.; Bacak, Asan; Khan, M. Anwar H.; Wright, Matthew D.; Priestley, Michael; Martin, Damien; Percival, Carl J.; Shallcross, Dudley E.

2017-01-01

People spend the majority of their time indoors and therefore the quality of indoor air is worthy of investigation; indoor air quality is affected by indoor sources of pollutants and from pollutants entering buildings from outdoors. In this study, unique perfluorocarbon tracers were released in five experiments at a 100 m and ~2 km distance from a large university building in Manchester, UK and tracer was also released inside the building to measure the amount of outdoor material penetrating into buildings and the flow of material within the building itself. Air samples of the tracer were taken in several rooms within the building, and a CO2 tracer was used within the building to estimate air-exchange rates. Air-exchange rates were found to vary between 0.57 and 10.90 per hour. Indoor perfluorocarbon tracer concentrations were paired to outdoor tracer concentrations, and in-out ratios were found to vary between 0.01 and 3.6. The largest room with the lowest air-exchange rate exhibited elevated tracer concentrations for over 60 min after the release had finished, but generally had the lowest concentrations, the room with the highest ventilation rates had the highest concentration over 30 min, but the peak decayed more rapidly. Tracer concentrations indoors compared to outdoors imply that pollutants remain within buildings after they have cleared outside, which must be considered when evaluating human exposure to outdoor pollutants. PMID:28230812

Inhibitory Effects of Semiochemicals on the Attraction of an Ambrosia Beetle Euwallacea nr. fornicatus to Quercivorol.

PubMed

Byers, John A; Maoz, Yonatan; Wakarchuk, David; Fefer, Daniela; Levi Zada, Anat

2018-04-17

The Euwallacea fornicatus (Eichhoff) species complex includes the polyphagous shot hole borer (PSHB), an ambrosia beetle infesting avocado limbs, Persea americana Mill. Synthetic quercivorol, a monoterpene alcohol, is known to attract females (males are flightless) over a range of release rates spanning three orders of magnitude. The upper release dose was extended 10-fold using sticky traps baited with quercivorol released at 1× (0.126 mg/day), 10×, and 108× relative rates to obtain a dose-response curve fitting a kinetic formation function. Naturally infested limbs of living avocado trees were wrapped with netting to exclude the possibility of catching emerging beetles on the encircling sticky traps. The results indicate PSHB are significantly attracted to infested limbs. Ethanol released over a 64-fold range (lowest rate of 7.5 mg/day) was moderately inhibitory of PSHB attraction to 1× quercivorol. β-caryophyllene and eucalyptol did not appear to affect attraction at the rates tested. A field test of potential inhibitors of 1× quercivorol was done using ~1 mg/day releases of monoterpene ketones: (-)-(S)-verbenone, (+)-(R)-verbenone, 3-methyl-2-cyclo-hexen-1-one (MCH or seudenone), piperitone, (+)-(S)-carvone, and racemic cryptone. Only piperitone and the two enantiomers of verbenone were strongly inhibitory. A blend of piperitone and verbenone tested together at different distances (0, 0.5, 1, 2, and 4 m) from a 1× quercivorol baited sticky trap became increasingly ineffective in inhibiting the attractant as separation distance increased. Due to the relatively short-range repellency (<1 m), the inhibitors would need to be released from several places on each tree to effectively repel PSHB from avocado trees. Effective attraction radii, EAR, and circular EARc are estimated for the quercivorol baits released at 1×, 10× and 108× rates. Push-pull simulations of moving beetles were performed in 1 ha plots with 2, 4, or 16 traps of 10× EARc and 400 trees (0, 1, or 3 inhibitors per tree) of which ten had an infested limb (EARc = 0.5 m). The simulations indicate that push-pull methods would be more effective in reducing PSHB mating than simply using mass-trapping alone.

Estimating the timing of quantal releases during end-plate currents at the frog neuromuscular junction.

PubMed Central

Van der Kloot, W

1988-01-01

1. Following motor nerve stimulation there is a period of greatly enhanced quantal release, called the early release period or ERP (Barrett & Stevens, 1972b). Until now, measurements of the probability of quantal releases at different points in the ERP have come from experiments in which quantal output was greatly reduced, so that the time of release of individual quanta could be detected or so that the latency to the release of the first quantum could be measured. 2. A method has been developed to estimate the timing of quantal release during the ERP that can be used at much higher levels of quantal output. The assumption is made that each quantal release generates an end-plate current (EPC) that rises instantaneously and then decays exponentially. The peak amplitude of the quantal currents and the time constant for their decay are measured from miniature end-plate currents (MEPCs). Then a number of EPCs are averaged, and the times of release of the individual quanta during the ERP estimated by a simple mathematical method for deconvolution derived by Cohen, Van der Kloot & Attwell (1981). 3. The deconvolution method was tested using data from preparations in high-Mg2+ low-Ca2+ solution. One test was to reconstitute the averaged EPCs from the estimated times of quantal release and the quantal currents, by using Fourier convolution. The reconstructions fit well to the originals. 4. Reconstructions were also made from averaged MEPCs which do not rise instantaneously and the estimated times of quantal release.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2466987

Monitoring and Evaluation of Smolt Migration in the Columbia Basin : Volume XVI : Survival and Transportation Effects for Migrating Snake River Hatchery Chinook Salmon and Steelhead: Historical Estimates from 1996-2003.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buchanan, Rebecca A.; Skalski, John R.

2007-12-07

In 2005, the University of Washington developed a new statistical model to analyze the combined juvenile and adult detection histories of PIT-tagged salmon migrating through the Federal Columbia River Power System (FCRPS). This model, implemented by software Program ROSTER (River-Ocean Survival and Transportation Effects Routine), has been used to estimate survival and transportation effects on large temporal and spatial scales for PIT-tagged hatchery spring and summer Chinook salmon and steelhead released in the Snake River Basin from 1996 to 2003. Those results are reported here. Annual estimates of the smolt-to-adult return ratio (SAR), juvenile inriver survival from Lower Granite tomore » Bonneville, the ocean return probability from Bonneville to Bonneville, and adult upriver survival from Bonneville to Lower Granite are reported. Annual estimates of transport-inriver (T/I) ratios and differential post-Bonneville mortality (D) are reported on both a systemwide basis, incorporating all transport dams analyzed, and a dam-specific basis. Transportation effects are estimated only for dams where at least 5,000 tagged smolts were transported from a given upstream release group. Because few tagged hatchery steelhead were transported in these years, no transportation effects are estimated for steelhead. Performance measures include age-1-ocean adult returns for steelhead, but not for Chinook salmon. Annual estimates of SAR from Lower Granite back to Lower Granite averaged 0.71% with a standard error (SE) of 0.18% for spring Chinook salmon from the Snake River Basin for tagged groups released from 1996 through 2003, omitting age-1-ocean (jack) returns. For summer Chinook salmon from the Snake River Basin, the estimates of annual SAR averaged 1.15% (SE=0.31%). Only for the release years 1999 and 2000 did the Chinook SAR approach the target value of 2%, identified by the NPCC as the minimum SAR necessary for recovery. Annual estimates of SAR for hatchery steelhead from the Snake River Basin averaged 0.45% (SE=0.11%), including age-1-ocean returns, for release years 1996 through 2003. For release years when the ocean return probability from Bonneville back to Bonneville could be estimated (i.e., 1999 through 2003), it was estimated that on average approximately 86% of the total integrated mortality for nontransported, tagged hatchery spring and summer Chinook, and 74% for steelhead, occurred during the ocean life stage (i.e., from Bonneville to Bonneville). This suggests that additional monitoring and research efforts should include the ocean and estuary environment. Annual estimates of the systemwide T/I are weighted averages of the dam-specific T/I ratios for each transport dam (with {ge} 5,000 tagged fish transported), weighted by the probabilities of being transported at each dam. The systemwide T/I compares the observed SAR under the existing transportation system with the expected SAR if the transportation system had not been operated. Estimates of 1.0 indicate that the systemwide transportation program has no effect on SAR, while estimates > 1.0 indicate that the transportation program increases SAR. Excluding the 2001 release group, the geometric mean of the systemwide T/I estimates for hatchery spring Chinook salmon from the Snake River Basin was 1.15 (SE=0.03) for release years 1997 through 2003. The geometric mean of the systemwide T/I estimates for hatchery summer Chinook salmon from the Snake River Basin was 1.28 (SE=0.13) for release years 1997 through 2000 and 2003. Estimates were much higher for the 2001 release groups. These estimates reflect transportation from Lower Granite and/or Little Goose for most release years, depending on the number of tagged smolts actually transported at each dam during each release year. Differential post-Bonneville mortality (D) is the ratio of post-Bonneville survival to Lower Granite Dam of transported fish to that of nontransported ('inriver') fish. Excluding the 2001 release year, the geometric mean of the D estimates for hatchery spring Chinook salmon from the Snake River Basin was 1.00 (SE=0.09) for release years 1997 through 2003. For hatchery summer Chinook salmon from the Snake River Basin, the geometric mean of the D estimates was 1.32 (SE=0.27) for release years 1997 through 2000 and 2003. These estimates reflect transportation from Lower Granite and/or Little Goose, depending on the number of tagged smolts actually transported at each dam during each release year. Approximately half the point estimates of D for both spring and summer Chinook salmon were 1.0 or greater, indicating that for those release groups, transported fish did not have lower ocean and adult survival than nontransported fish. For those years with estimates of D < 1.0, the systemwide T/I estimates were always {ge} 1.0, indicating that despite lower ocean and adult survival of transported fish, transportation did not lower SAR overall.« less

Release of juvenile water on Mars - Estimated amounts and timing associated with volcanism

NASA Technical Reports Server (NTRS)

Greeley, Ronald

1987-01-01

The amount of water released on Mars in association with volcanism is estimated to equal a layer 46 meters deep over the entire planet. Most of this water was released in the first 2 billion years of Martian history. The estimate is based on mapping the volcanic materials and by inferring the volatile content of the lavas. Water from other sources, such as plutonic activity and cometary contributions, is not included in the estimate.

Incidence of Posttransplantation Diabetes Mellitus in De Novo Kidney Transplant Recipients Receiving Prolonged-Release Tacrolimus-Based Immunosuppression With 2 Different Corticosteroid Minimization Strategies: ADVANCE, A Randomized Controlled Trial

PubMed Central

Mourad, Georges; Glyda, Maciej; Albano, Laetitia; Viklický, Ondrej; Merville, Pierre; Tydén, Gunnar; Mourad, Michel; Lõhmus, Aleksander; Witzke, Oliver; Christiaans, Maarten H. L.; Brown, Malcolm W.; Undre, Nasrullah; Kazeem, Gbenga; Kuypers, Dirk R. J.

2017-01-01

Background ADVANCE (NCT01304836) was a phase 4, multicenter, prospectively randomized, open-label, 24-week study comparing the incidence of posttransplantation diabetes mellitus (PTDM) with 2 prolonged-release tacrolimus corticosteroid minimization regimens. Methods All patients received prolonged-release tacrolimus, basiliximab, mycophenolate mofetil and 1 bolus of intraoperative corticosteroids (0-1000 mg) as per center policy. Patients in arm 1 received tapered corticosteroids, stopped after day 10, whereas patients in arm 2 received no steroids after the intraoperative bolus. The primary efficacy variable was the diagnosis of PTDM as per American Diabetes Association criteria (2010) at any point up to 24 weeks postkidney transplantation. Secondary efficacy variables included incidence of composite efficacy failure (graft loss, biopsy-proven acute rejection or severe graft dysfunction: estimated glomerular filtration rate (Modification of Diet in Renal Disease-4) <30 mL/min per 1.73 m2), acute rejection and graft and patient survival. Results The full-analysis set included 1081 patients (arm 1: n = 528, arm 2: n = 553). Baseline characteristics and mean tacrolimus trough levels were comparable between arms. Week 24 Kaplan–Meier estimates of PTDM were similar for arm 1 versus arm 2 (17.4% vs 16.6%; P = 0.579). Incidence of composite efficacy failure, graft and patient survival, and mean estimated glomerular filtration rate were also comparable between arms. Biopsy-proven acute rejection and acute rejection were significantly higher in arm 2 versus arm 1 (13.6% vs 8.7%, P = 0.006 and 25.9% vs 18.2%, P = 0.001, respectively). Tolerability profiles were comparable between arms. Conclusions A prolonged-release tacrolimus, basiliximab, and mycophenolate mofetil immunosuppressive regimen is efficacious, with a low incidence of PTDM and a manageable tolerability profile over 24 weeks of treatment. A lower incidence of biopsy-proven acute rejection was seen in patients receiving corticosteroids tapered over 10 days plus an intraoperative corticosteroid bolus versus those receiving an intraoperative bolus only. PMID:27547871

Enhanced oxidative weathering in glaciated mountain catchments: A stabilising feedback on atmospheric carbon dioxide?

NASA Astrophysics Data System (ADS)

Horan, K.; Hilton, R. G.; Burton, K. W.; Selby, D. S.; Ottley, C. J.

2015-12-01

Mountain belts act as sources of carbon dioxide (CO2) to the atmosphere if physical erosion and exhumation expose rock-derived organic carbon ('petrogenic' organic carbon, OCpetro) to chemical weathering. Estimates suggest 15x1021g of carbon is stored in rocks globally as OCpetro, ~25,000 times the amount of carbon in the pre-industrial atmosphere. Alongside volcanic and metamorphic degassing, OCpetro weathering is thought to be the main source of CO2 to the atmosphere over geological timescales. Erosion in mountain river catchments has been shown to enhance oxidative weathering and CO2 release. However, we still lack studies which quantify this process. In addition, it is not clear how glaciation may impact OCpetro oxidation. In analogy with silicate weathering, large amounts of fine sediment in glacial catchments may enhance oxidative weathering. Here we quantify oxidative weathering in nine catchments draining OCpetro bearing rocks in the western Southern Alps, New Zealand. Using rhenium (Re) as a tracer of oxidative weathering, we develop techniques to precisely measure Re concentration at sub-ppt levels in river waters. Using [Re]water/[Re]rock as a weathering tracer, we estimate that the weathering efficiency in glacial catchments is >4 times that of non-glacial catchments. Combining this with the OCpetro content of rocks and dissolved Re flux, we estimate the CO2 release by OCpetro oxidation. The analysis suggests that non-glacial catchments in the western Southern Alps release similar amounts of CO2 as catchments in Taiwan where erosion rates are comparable. In this mountain belt, the CO2 release does not negate CO2 drawdown by silicate weathering and by riverine transfer of organic matter. Based on our results, we propose that mountain glaciation may greatly enhance OCpetro oxidation rates. Depending on the global fluxes involved, this provides a feedback to damp low atmospheric CO2 levels and global cooling. During glacial periods (low CO2, low global temperatures), increased CO2 emissions by OCpetro oxidation in mountain belts may act to counter global cooling.

The volcanic explosivity index /VEI/ - An estimate of explosive magnitude for historical volcanism

NASA Technical Reports Server (NTRS)

Newhall, C. G.; Self, S.

1982-01-01

A composite estimate of the magnitude of past explosive eruptions, referred to as the Volcanic Explosivity Index (VEI), is proposed as a semiquantitative compromise between poor data and the need in various disciplines to evaluate the record of past volcanism. The VEI is assigned to more than 8000 historic and prehistoric eruptions. It is shown that the VEI can help detect incompleteness and reporting biases and can help in selecting subsets of the historical record suitable for each study. The VEI is a composite estimate of Walkers (1980) magnitude and/or intensity and/or destructiveness and/or (less frequently) dispersive power, violence, and energy release rate, depending on the data that are available.

White paper updating conclusions of 1998 ILAW performance assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

MANN, F.M.

The purpose of this document is to provide a comparison of the estimated immobilized low-activity waste (LAW) disposal system performance against established performance objectives using the beat estimates for parameters and models to describe the system. The principal advances in knowledge since the last performance assessment (known as the 1998 ILAW PA [Mann 1998a]) have been in site specific information and data on the waste form performance for BNFL, Inc. relevant glass formulations. The white paper also estimates the maximum release rates for technetium and other key radionuclides and chemicals from the waste form. Finally, this white paper provides limitedmore » information on the impact of changes in waste form loading.« less

Estimation of radionuclide (137Cs) emission rates from a nuclear power plant accident using the Lagrangian Particle Dispersion Model (LPDM).

PubMed

Park, Soon-Ung; Lee, In-Hye; Ju, Jae-Won; Joo, Seung Jin

2016-10-01

A methodology for the estimation of the emission rate of 137 Cs by the Lagrangian Particle Dispersion Model (LPDM) with the use of monitored 137 Cs concentrations around a nuclear power plant has been developed. This method has been employed with the MM5 meteorological model in the 600 km × 600 km model domain with the horizontal grid scale of 3 km × 3 km centered at the Fukushima nuclear power plant to estimate 137 Cs emission rate for the accidental period from 00 UTC 12 March to 00 UTC 6 April 2011. The Lagrangian Particles are released continuously with the rate of one particle per minute at the first level modelled, about 15 m above the power plant site. The presently developed method was able to simulate quite reasonably the estimated 137 Cs emission rate compared with other studies, suggesting the potential usefulness of the present method for the estimation of the emission rate from the accidental power plant without detailed inventories of reactors and fuel assemblies and spent fuels. The advantage of this method is not so complicated but can be applied only based on one-time forward LPDM simulation with monitored concentrations around the power plant, in contrast to other inverse models. It was also found that continuously monitored radionuclides concentrations from possibly many sites located in all directions around the power plant are required to get accurate continuous emission rates from the accident power plant. The current methodology can also be used to verify the previous version of radionuclides emissions used among other modeling groups for the cases of intermittent or discontinuous samplings. Copyright © 2016. Published by Elsevier Ltd.

High Gravity (g) Combustion

DTIC Science & Technology

2006-02-01

UNICORN (Unsteady Ignition and Combustion with Reactions) code10. Flame propagation in a tube that is 50-mm wide and 1000-mm long (similar to that...turbine engine manufacturers, estimating the primary zone space heating rate. Both combustion systems, from Company A and Company B, required a much...MBTU/atm-hr-ft3) Te m pe ra tu re R is e (K ) dP/P = 2% dP/P = 2.5% dP/P = 3% dP/P = 3.5% dP/P = 4% Company A Company B Figure 13: Heat Release Rate

Sexual Violence Inside Prisons: Rates of Victimization

PubMed Central

Blitz, Cynthia L.; Shi, Jing; Bachman, Ronet; Siegel, Jane A.

2006-01-01

People in prison are exposed to and experience sexual violence inside prisons, further exposing them to communicable diseases and trauma. The consequences of sexual violence follow the individual into the community upon release. This paper estimates the prevalence of sexual victimization within a state prison system. A total of 6,964 men and 564 women participated in a survey administered using audio-CASI. Weighted estimates of prevalence were constructed by gender and facility size. Rates of sexual victimization varied significantly by gender, age, perpetrator, question wording, and facility. Rates of inmate-on-inmate sexual victimization in the previous 6 months were highest for female inmates (212 per 1,000), more than four times higher than male rates (43 per 1,000). Abusive sexual conduct was more likely between inmates and between staff and inmates than nonconsensual sexual acts. Sexual violence inside prison is an urgent public health issue needing targeted interventions to prevent and ameliorate its health and social consequences, which spatially concentrate in poor inner-city areas where these individuals ultimately return. PMID:16937087

Methane emissions and contaminant degradation rates at sites affected by accidental releases of denatured fuel-grade ethanol

NASA Astrophysics Data System (ADS)

Sihota, Natasha J.; Mayer, K. Ulrich; Toso, Mark A.; Atwater, Joel F.

2013-08-01

The recent increase in the use of denatured fuel-grade ethanol (DFE) has enhanced the probability of its environmental release. Due to the highly labile nature of ethanol (EtOH), it is expected to rapidly biodegrade, increasing the potential for inducing methanogenic conditions in the subsurface. As environmental releases of DFE can be expected to occur at the ground surface or in the vadose zone (e.g., due to surficial spills from rail lines or tanker trucks and leaking underground storage tanks), the potential for methane (CH4) generation at DFE spill sites requires evaluation. An assessment is needed because high CH4 generation rates may lead to CH4 fluxes towards the ground surface, which is of particular concern if spills are located close to human habitation—related to concerns of soil vapor intrusion (SVI). This work demonstrates, for the first time, the measurement of surficial gas release rates at large volume DFE spill sites. Two study sites, near Cambria and Balaton, in MN are investigated. Total carbon emissions at the ground surface (summing carbon dioxide (CO2) and CH4 emissions) are used to quantify depth-integrated DFE degradation rates. Results from both sites demonstrate that substantial CO2 and CH4 emissions do occur—even years after a spill. However, large total carbon fluxes, and CH4 emissions in particular, were restricted to a localized area within the DFE source zone. At the Balaton site, estimates of total DFE carbon losses in the source zone ranged between 5 and 174 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 9 μmol m- 2 s- 1. At the Cambria site estimates of total DFE carbon losses in the source zone ranged between 8 and 500 μmol m- 2 s- 1, and CH4 effluxes ranged between non-detect and 393 μmol m- 2 s- 1. Substantial CH4 accumulation, coupled with oxygen (O2) depletion, measured in samples collected from custom-designed gas collection chambers at the Cambria site suggests that the development of explosion or asphyxiation hazards is possible in confined spaces above a rapidly degrading DFE release. However, the results also indicate that the development of such hazards is locally constrained, will require a high degree of soil moisture, close proximity to the source zone, a good connection between the soil and the confined space, and poorly aerated conditions.

Methane emissions and contaminant degradation rates at sites affected by accidental releases of denatured fuel-grade ethanol.

PubMed

Sihota, Natasha J; Mayer, K Ulrich; Toso, Mark A; Atwater, Joel F

2013-08-01

The recent increase in the use of denatured fuel-grade ethanol (DFE) has enhanced the probability of its environmental release. Due to the highly labile nature of ethanol (EtOH), it is expected to rapidly biodegrade, increasing the potential for inducing methanogenic conditions in the subsurface. As environmental releases of DFE can be expected to occur at the ground surface or in the vadose zone (e.g., due to surficial spills from rail lines or tanker trucks and leaking underground storage tanks), the potential for methane (CH4) generation at DFE spill sites requires evaluation. An assessment is needed because high CH4 generation rates may lead to CH4 fluxes towards the ground surface, which is of particular concern if spills are located close to human habitation-related to concerns of soil vapor intrusion (SVI). This work demonstrates, for the first time, the measurement of surficial gas release rates at large volume DFE spill sites. Two study sites, near Cambria and Balaton, in MN are investigated. Total carbon emissions at the ground surface (summing carbon dioxide (CO2) and CH4 emissions) are used to quantify depth-integrated DFE degradation rates. Results from both sites demonstrate that substantial CO2 and CH4 emissions do occur-even years after a spill. However, large total carbon fluxes, and CH4 emissions in particular, were restricted to a localized area within the DFE source zone. At the Balaton site, estimates of total DFE carbon losses in the source zone ranged between 5 and 174 μmol m(-2) s(-1), and CH4 effluxes ranged between non-detect and 9 μmol m(-2) s(-1). At the Cambria site estimates of total DFE carbon losses in the source zone ranged between 8 and 500 μmol m(-2) s(-1), and CH4 effluxes ranged between non-detect and 393 μmol m(-2) s(-1). Substantial CH4 accumulation, coupled with oxygen (O2) depletion, measured in samples collected from custom-designed gas collection chambers at the Cambria site suggests that the development of explosion or asphyxiation hazards is possible in confined spaces above a rapidly degrading DFE release. However, the results also indicate that the development of such hazards is locally constrained, will require a high degree of soil moisture, close proximity to the source zone, a good connection between the soil and the confined space, and poorly aerated conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

Survival Estimates for the Passage of Juvenile Salmonids through Snake River Dams and Reservoirs, 1994 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muir, William D.

1995-02-01

In 1994, the National Marine Fisheries Service and the University of Washington completed the second year of a multi-year study to estimate survival of juvenile salmonids (Oncorhynchus spp.) passing through the dams and reservoirs of the Snake River. Actively migrating smolts were collected at selected locations above, at, and below Lower Granite Dam, tagged with passive integrated transponder (PIT) tags, and released to continue their downstream migration. Survival estimates were calculated using the Single-Release, Modified Single-Release, and Paired-Release Models.

Field evaluation of effect of temperature on release of Disparlure from a pheromone-baited trapping system used to monitor gypsy moth (Lepidoptera: Lymantriidae)

Treesearch

Patrick C. Tobin; Aijun Zhang; Ksenia Onufrieva; Donna Leonard

2011-01-01

Traps baited with disparlure, the synthetic form of the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), sex pheromone are used to detect newly founded populations and estimate population density across the United States. The lures used in trapping devices are exposed to field conditions with varying climates, which can affect the rate...

Estimating foundation water vapor release using a simple moisture balance and AIM-2 : case study of a contemporary wood-frame house

Treesearch

C. R. Boardman; Samuel V. Glass; Charles G. Carll

2010-01-01

Proper management of indoor humidity in buildings is an essential aspect of durability. Following dissipation of moisture from construction materials, humidity levels during normal operation are generally assumed to primarily depend on the building volume, the number of building occupants and their behavior, the air exchange rate, and the water vapor content of outdoor...

A feasibility analysis of the employment of satellite imagery to monitor and inspect surface mining operations in western Kentucky, volume 1

NASA Technical Reports Server (NTRS)

Fish, B. R. (Principal Investigator)

1977-01-01

The author has identified the following significant results. Surface mining violation estimates were scaled by scores assigned by ten inspectors from western Kentucky to each violation. A sensitivity analysis was made by varying the violation costs; costs were varied by using three different average durations. These durations were: (1) best estimated duration; (2) longest possible duration as restricted by the one year permit renewal and bond release regulations, and (3) shortest possible duration when inspections were made. If a social cost cannot be reduced, then the value of the social cost is irrelevant. Indications from the increased inspection rate of 1975 were that the total amount of fines collected per year remains constant independent of the increased detection rate.

Dipicolinic Acid Release and the Germination of Alicyclobacillus acidoterrestris Spores under Nutrient Germinants.

PubMed

Porębska, Izabela; Sokołowska, Barbara; Woźniak, Łukasz

2017-03-30

The presence of Alicyclobacillus, a thermoacidophilic and spore-forming bacterium, in acidic fruit juices poses a serious problem for the processing industry. A typical sign of spoilage in contaminated juices is a characteristic phenolic off-flavour associated with the production of guaiacol. Spores are formed in response to starvation and in a natural environment re-access the nutrients, e.g.: L-alanine and AGFK - a mixture of asparagine, glucose, fructose and potassium, triggers germination. The aim of this study was to estimate the impact of L-alanine and AGFK on the germination of the spores of two Alicyclobacillus acidoterrestris strains and to evaluate the relationship of the germination rate with dipicolinic acid (DPA) release. The spores were suspended in apple juice or in buffers at pH 4 and pH 7, followed by the addition of L-alanine and AGFK. Suspensions were or were not subjected, to a temperature of 80°C/10 min and incubated for various periods of time at 45°C. Optical density (OD660) was used to estimate the number of germinated spores. The amount of DPA released was determined using HPLC. The results indicate that the degree of germination of A. acidoterrestris spores depended on the strain and time of incubation and the nutritious compounds used. The data obtained show that the amount of DPA released correlated to the number of A. acidoterrestris spores germinated.

Fire Ant Decapitating Fly Cooperative Release Programs (1994–2008): Two Pseudacteon Species, P. tricuspis and P. curvatus, Rapidly Expand Across Imported Fire Ant Populations in the Southeastern United States

PubMed Central

Callcott, Anne-Marie A.; Porter, Sanford D.; Weeks, Ronald D.; “Fudd” Graham, L. C.; Johnson, Seth J.; Gilbert, Lawrence E.

2011-01-01

Natural enemies of the imported fire ants, Solenopsis invicta Buren S. richteri Forel (Hymenoptera: Formicidae), and their hybrid, include a suite of more than 20 fire ant decapitating phorid flies from South America in the genus Pseudacteon. Over the past 12 years, many researchers and associates have cooperated in introducing several species as classical or self-sustaining biological control agents in the United States. As a result, two species of flies, Pseudacteon tricuspis Borgmeier and P. curvatus Borgmeier (Diptera: Phoridae), are well established across large areas of the southeastern United States. Whereas many researchers have published local and state information about the establishment and spread of these flies, here distribution data from both published and unpublished sources has been compiled for the entire United States with the goal of presenting confirmed and probable distributions as of the fall of 2008. Documented rates of expansion were also used to predict the distribution of these flies three years later in the fall of 2011. In the fall of 2008, eleven years after the first successful release, we estimate that P. tricuspis covered about 50% of the fire ant quarantined area and that it will occur in almost 65% of the quarantine area by 2011. Complete coverage of the fire ant quarantined area will be delayed or limited by this species' slow rate of spread and frequent failure to establish in more northerly portions of the fire ant range and also, perhaps, by its preference for red imported fire ants (S. invicta). Eight years after the first successful release of P. curvatus, two biotypes of this species (one biotype occurring predominantly in the black and hybrid imported fire ants and the other occurring in red imported fire ants) covered almost 60% of the fire ant quarantined area. We estimate these two biotypes will cover almost 90% of the quarantine area by 2011 and 100% by 2012 or 2013. Strategic selection of several distributional gaps for future releases will accelerate complete coverage of quarantine areas. However, some gaps may be best used for the release of additional species of decapitating flies because establishment rates may be higher in areas without competing species. PMID:21526930

Release kinetics of papaverine hydrochloride from tablets with different excipients.

PubMed

Kasperek, Regina; Polski, Andrzej; Zimmer, Łukasz; Poleszak, Ewa

2014-01-01

The influence of excipients on the disintegration times of tablets and the release of papaverine hydrochloride (PAP) from tablets were studied. Ten different formulations of tablets with PAP were prepared by direct powder compression. Different binders, disintegrants, fillers, and lubricants were used as excipients. The release of PAP was carried out in the paddle apparatus using 0.1 N HCl as a dissolution medium. The results of the disintegration times of tablets showed that six formulations can be classified as fast dissolving tablets (FDT). FDT formulations contained Avicel PH 101, Avicel PH 102, mannitol, (3-lactose, PVP K 10, gelatinized starch (CPharmGel), Prosolv Easy Tab, Prosolv SMCC 90, magnesium stearate, and the addition of disintegrants such as AcDiSol and Kollidon CL. Drug release kinetics were estimated by the zero- and first-order, Higuchi release rate, and Korsmeyer-Peppas models. Two formulations of the tablets containing PVP (K10) (10%), CPharmGel (10% and 25%), and Prosolv Easy Tab (44% and 60%) without the addition of a disintegrant were well-fitted to the kinetics models such as the Higuchi and zero-order, which are suitable for controlled- or sustained-release.

Release Kinetics of Papaverine Hydrochloride from Tablets with Different Excipients

PubMed Central

Kasperek, Regina; Polski, Andrzej; Zimmer, Łukasz; Poleszak, Ewa

2014-01-01

Abstract The influence of excipients on the disintegration times of tablets and the release of papaverine hydrochloride (PAP) from tablets were studied. Ten different formulations of tablets with PAP were prepared by direct powder compression. Different binders, disintegrants, fillers, and lubricants were used as excipients. The release of PAP was carried out in the paddle apparatus using 0.1 N HCl as a dissolution medium. The results of the disintegration times of tablets showed that six formulations can be classified as fast dissolving tablets (FDT). FDT formulations contained Avicel PH 101, Avicel PH 102, mannitol, (3-lactose, PVP K 10, gelatinized starch (CPharmGel), Prosolv Easy Tab, Prosolv SMCC 90, magnesium stearate, and the addition of disintegrants such as AcDiSol and Kollidon CL. Drug release kinetics were estimated by the zero- and first-order, Higuchi release rate, and Korsmeyer-Peppas models. Two formulations of the tablets containing PVP (K10) (10%), CPharmGel (10% and 25%), and Prosolv Easy Tab (44% and 60%) without the addition of a disintegrant were well-fitted to the kinetics models such as the Higuchi and zero-order, which are suitable for controlled- or sustained-release. PMID:25853076

Survival of captive-reared Puerto Rican Parrots released in the Caribbean National Forest

USGS Publications Warehouse

White, T.H.; Collazo, J.A.; Vilella, F.J.

2005-01-01

We report first-year survival for 34 captive-reared Puerto Rican Parrots (Amazona vittata) released in the Caribbean National Forest, Puerto Rico between 2000 and 2002. The purpose of the releases were to increase population size and the potential number of breeding individuals of the sole extant wild population, and to refine release protocols for eventual reintroduction of a second wild population elsewhere on the island. After extensive prerelease training, we released 10 parrots in 2000, 16 parrots in 2001, and eight parrots in 2002 ranging in age from 1-4 years old. All birds were equipped with radio-transmitters to monitor survival. The overall first-year survival estimate for the 34 parrots was 41% (CI = 22%-61%). Only one parrot died within the first week postrelease, with most (94%) surviving for at least eight weeks after release. Most (54%) documented mortalities were due to raptor predation, which claimed 21% of all released parrots. A captive-reared bird (male, age one), released in 2001, paired with a wild female and fledged two young in 2004. We also calculated survival based on 0% and 50% of observed predation losses and found hypothetical survival rates of 72% and 54%, respectively. Rigorous prerelease training and acclimation was believed to have improved initial postrelease parrot survival, and releasing mixed age-class groups suggests the potential for shortening the time to recruitment. ?? The Cooper Ornithological Society 2005.

Life Cycle Assessment and Release Studies for 15 Nanosilver-Enabled Consumer Products: Investigating Hotspots and Patterns of Contribution.

PubMed

Pourzahedi, Leila; Vance, Marina; Eckelman, Matthew J

2017-06-20

Increasing use of silver nanoparticles (AgNPs) in consumer products as antimicrobial agents has prompted extensive research toward the evaluation of their potential release to the environment and subsequent ecotoxicity to aquatic organisms. It has also been shown that AgNPs can pose significant burdens to the environment from life cycle emissions associated with their production, but these impacts must be considered in the context of actual products that contain nanosilver. Here, a cradle-to-gate life cycle assessment for the production of 15 different AgNP-enabled consumer products was performed, coupled with release studies of those same products, thus providing a consistent analytical platform for investigation of potential nanosilver impacts across a range of product types and concentrations. Environmental burdens were assessed over multiple impact categories defined by the United States Environmental Protection Agency's Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI 2.1) method. Depending on the product composition and silver loading, the contribution of AgNP synthesis to the overall impacts was seen to vary over a wide range from 1% to 99%. Release studies found that solid polymeric samples lost more silver during wash compared to fibrous materials. Estimates of direct ecotoxicity impacts of AgNP releases from those products with the highest leaching rates resulted in lower impact levels compared to cradle-to-gate ecotoxicity from production for those products. Considering both cradle-to-gate production impacts and nanoparticle release studies, in conjunction with estimates of life cycle environmental and health benefits of nanoparticle incorporation, can inform sustainable nanoenabled product design.

The impact of health plan report cards on managed care enrollment.

PubMed

Scanlo, Dennis P; Chernew, Michael; Mclaughlin, Catherine; Solon, Gary

2002-01-01

How does the release of health plan performance ratings influence employee health plan choice? A natural experiment at General Motors (GM) Corporation provides valuable evidence on this question. During the 1997 open enrollment period, GM disseminated a health plan report card for the first time. By comparing 1996 and 1997 enrollment patterns, our analysis estimates the impact of the report card information while accounting for fixed, unobserved plan traits. Results indicate that employees are less likely to enroll in plans requiring relatively high out-of-pocket contributions. Results with respect to report card ratings suggest that individuals avoid health plans with many below average ratings.

Impact of Release Rates on the Effectiveness of Augmentative Biological Control Agents

PubMed Central

Crowder, David W.

2007-01-01

To access the effect of augmentative biological control agents, 31 articles were reviewed that investigated the impact of release rates of 35 augmentative biological control agents on the control of 42 arthropod pests. In 64% of the cases, the release rate of the biological control agent did not significantly affect the density or mortality of the pest insect. Results where similar when parasitoidsor predators were utilized as the natural enemy. Within any order of natural enemy, there were more cases where release rates did not affect augmentative biological control than cases where release rates were significant. There were more cases in which release rates did not affect augmentative biological control when pests were from the orders Hemiptera, Acari, or Diptera, but not with pests from the order Lepidoptera. In most cases, there was an optimal release rate that produced effective control of a pest species. This was especially true when predators were used as a biological control agent. Increasing the release rate above the optimal rate did not improve control of the pest and thus would be economically detrimental. Lower release rates were of ten optimal when biological control was used in conjunction with insecticides. In many cases, the timing and method of biological control applications were more significant factors impacting the effectiveness of biological control than the release rate. Additional factors that may limit the relative impact of release rates include natural enemy fecundity, establishment rates, prey availability, dispersal, and cannibalism. PMID:20307240

Effects of cryopreservation on chimeric antigen receptor T cell functions.

PubMed

Xu, Hao; Cao, Wenyue; Huang, Liang; Xiao, Min; Cao, Yang; Zhao, Lei; Wang, Na; Zhou, Jianfeng

2018-06-14

Chimeric antigen receptor T (CART) cell therapy has emerged as a potentially curative "drug" for cancer treatment. Cryopreservation of CART cells is necessary for their clinical application. Systematic studies on the effects of cryopreservation on the antitumor function of CART cells are lacking. Therefore, we compared the phenotypes and functions of CART cells that were cryopreserved during ex vivo expansion with those of freshly isolated populations. T cells expressing an anti-B-cell-maturation-antigen (BCMA) chimeric antigen receptor (CAR) were expanded in vitro for 10 days and then cryopreserved. After one month, the cells were resuscitated, and their transduction rates, apoptosis rates and cell subsets were examined via flow cytometry. The results indicated no significant changes in transduction rates or cell subsets, and the survival rate of the resuscitated cells was approximately 90% Furthermore, similar tumoricidal effects and degranulation functions of the resuscitated cells compared with normally cultured cells were verified by calcein release and CD107a assays. A NOD/SCID mouse model was used to estimate the differences in the in vivo antitumor effects of the cryopreserved and normally cultured T cells, but no significant differences were observed. Following co-culture with several target cell types, the cytokines released by the cryopreserved and normally cultured T cells were measured via enzyme-linked immunosorbent assays (ELISAs). The results revealed that the release of interleukin-2 (IL-2), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) was significantly decreased. These data demonstrated that with the exception of a decrease in cytokine release, the cryopreserved CART cells retained their antitumor functions. Copyright © 2018. Published by Elsevier Inc.

Measurements of Methane Emissions and Volatile Organic Compounds from Shale Gas Operations in the Marcellus Shale

NASA Astrophysics Data System (ADS)

Omara, M.; Subramanian, R.; Sullivan, M.; Robinson, A. L.; Presto, A. A.

2014-12-01

The Marcellus Shale is the most expansive shale gas reserve in play in the United States, representing an estimated 17 to 29 % of the total domestic shale gas reserves. The rapid and extensive development of this shale gas reserve in the past decade has stimulated significant interest and debate over the climate and environmental impacts associated with fugitive releases of methane and other pollutants, including volatile organic compounds. However, the nature and magnitude of these pollutant emissions remain poorly characterized. This study utilizes the tracer release technique to characterize total fugitive methane release rates from natural gas facilities in southwestern Pennsylvania and West Virginia that are at different stages of development, including well completion flowbacks and active production. Real-time downwind concentrations of methane and two tracer gases (acetylene and nitrous oxide) released onsite at known flow rates were measured using a quantum cascade tunable infrared laser differential absorption spectrometer (QC-TILDAS, Aerodyne, Billerica, MA) and a cavity ring down spectrometer (Model G2203, Picarro, Santa Clara, CA). Evacuated Silonite canisters were used to sample ambient air during downwind transects of methane and tracer plumes to assess volatile organic compounds (VOCs). A gas chromatograph with a flame ionization detector was used to quantify VOCs following the EPA Method TO-14A. A preliminary assessment of fugitive emissions from actively producing sites indicated that methane leak rates ranged from approximately 1.8 to 6.2 SCFM, possibly reflecting differences in facility age and installed emissions control technology. A detailed comparison of methane leak rates and VOCs emissions with recent published literature for other US shale gas plays will also be discussed.

Constraints on the frequency-magnitude relation and maximum magnitudes in the UK from observed seismicity and glacio-isostatic recovery rates

NASA Astrophysics Data System (ADS)

Main, Ian; Irving, Duncan; Musson, Roger; Reading, Anya

1999-05-01

Earthquake populations have recently been shown to have many similarities with critical-point phenomena, with fractal scaling of source sizes (energy or seismic moment) corresponding to the observed Gutenberg-Richter (G-R) frequency-magnitude law holding at low magnitudes. At high magnitudes, the form of the distribution depends on the seismic moment release rate Msolar and the maximum magnitude m_max . The G-R law requires a sharp truncation at an absolute maximum magnitude for finite Msolar. In contrast, the gamma distribution has an exponential tail which allows a soft or `credible' maximum to be determined by negligible contribution to the total seismic moment release. Here we apply both distributions to seismic hazard in the mainland UK and its immediate continental shelf, constrained by a mixture of instrumental, historical and neotectonic data. Tectonic moment release rates for the seismogenic part of the lithosphere are calculated from a flexural-plate model for glacio-isostatic recovery, constrained by vertical deformation rates from tide-gauge and geomorphological data. Earthquake focal mechanisms in the UK show near-vertical strike-slip faulting, with implied directions of maximum compressive stress approximately in the NNW-SSE direction, consistent with the tectonic model. Maximum magnitudes are found to be in the range 6.3-7.5 for the G-R law, or 7.0-8.2 m_L for the gamma distribution, which compare with a maximum observed in the time period of interest of 6.1 m_L . The upper bounds are conservative estimates, based on 100 per cent seismic release of the observed vertical neotectonic deformation. Glacio-isostatic recovery is predominantly an elastic rather than a seismic process, so the true value of m_max is likely to be nearer the lower end of the quoted range.

River fluxes to the sea from the oceanʼs 10Be/9Be ratio

NASA Astrophysics Data System (ADS)

von Blanckenburg, Friedhelm; Bouchez, Julien

2014-02-01

The ratio of the meteoric cosmogenic radionuclide 10Be to the stable isotope 9Be is proposed here to be a flux proxy of terrigenous input into the oceans. The ocean's dissolved 10Be/9Be is set by (1) the flux of meteoric 10Be produced in the atmosphere; (2) the denudational flux of the rivers discharging into a given ocean basin; (3) the fraction of 9Be that is released from primary minerals during weathering (meaning the 9Be transported by rivers in either the dissolved form or adsorbed onto sedimentary particles and incorporated into secondary oxides); and (4) the fraction of riverine 10Be and 9Be actually released into seawater. Using published 10Be/9Be data of rivers for which independent denudation rate estimates exist we first find that the global average fraction of 9Be released during weathering into river waters and their particulate load is 20% and does not depend on denudation rate. We then evaluate this quantitative proxy for terrigenous inputs by using published dissolved seawater Be isotope data and a compilation of global river loads. We find that the measured global average oceanic dissolved 10Be/9Be ratio of about 0.9×10-7 is satisfied by the mass balance if only about 6% of the dissolved and adsorbed riverine Be is eventually released to the open ocean after escaping the coastal zone. When we establish this mass balance for individual ocean basins good agreement results between 10Be/9Be ratios predicted from known river basin denudation rates and measured ocean 10Be/9Be ratios. Only in the South Atlantic and the South Pacific the 10Be/9Be ratio is dominated by advected Be and in these basins the ratio is a proxy for ocean circulation. As the seawater 10Be/9Be ratio is faithfully recorded in marine chemical precipitates the 10Be/9Be ratio extracted from authigenic sediments can now serve to estimate relative changes in terrigenous input into the oceans back through time on a global and on an ocean basin scale.

Mountain respiration: Rates and patterns of fossil organic carbon oxidation revealed using the trace element rhenium

NASA Astrophysics Data System (ADS)

Hilton, R. G.; Gaillardet, J.; Calmels, D.; Birck, J.

2013-12-01

Fossil organic carbon (OCfossil) from sedimentary rocks can contribute to the carbon stock within the deepest part of soil. OCfossil constitutes a vast stock of carbon that was sequestered from the atmosphere in the geological past, containing ~15x106 PgC, which is approximately 25,000 times the carbon content of the pre-industrial atmosphere. Oxidation of OCfossil during chemical weathering at Earth's surface is thought to be a major source of carbon dioxide (CO2) to the atmosphere. It has been proposed that OCfossil oxidation occurs when fresh sedimentary rocks are exposed to oxygenated water, with the rate of CO2 release controlled by the supply of OCfossil to react. As such, mountain belts where high rates of physical erosion provide an abundant supply of OCfossil to the soil critical zone should be locations where this CO2 source is most potent. However, the rates of OCfossil oxidation during weathering remain poorly constrained. Here we use the trace element rhenium (Re) to shed new light on the rates and patterns of OCfossil oxidation across the landscape. Re is known to be associated with organic matter in rocks and following oxidation forms a soluble anion which contributes to the dissolved load of rivers. Rivers can offer an integrated signal of chemical reactions occurring across the landscape, and so by quantifying the dissolved Re flux we are able to estimate the corresponding release of CO2 by OCfossil weathering. Using a set of mountain river catchments in Taiwan, where water and sediment fluxes are well quantified, we estimate that the rates of CO2 output by this process are significant, and encroach on values expected for net biome productivity. We find that OCfossil oxidation rates are strongly linked to physical erosion rate at the catchment-scale. This suggests that changes in the rates of surface processes may alter this CO2 output from deep soils. On longer timescales, our findings suggest that the total CO2 output by OCfossil weathering in Taiwan does not negate estimates of CO2 sequestration by erosion and sedimentary burial of recent organic matter. Our findings suggest that mountain building in the tropic can result in a net sink of organic carbon during erosion and weathering which acts to sequester atmospheric CO2.

Bioreactor validation and biocompatibility of Ag/poly(N-vinyl-2-pyrrolidone) hydrogel nanocomposites.

PubMed

Jovanović, Zeljka; Radosavljević, Aleksandra; Kačarević-Popović, Zorica; Stojkovska, Jasmina; Perić-Grujić, Aleksandra; Ristić, Mirjana; Matić, Ivana Z; Juranić, Zorica D; Obradovic, Bojana; Mišković-Stanković, Vesna

2013-05-01

Silver/poly(N-vinyl-2-pyrrolidone) (Ag/PVP) nanocomposites containing Ag nanoparticles at different concentrations were synthesized using γ-irradiation. Cytotoxicity of the obtained nanocomposites was determined by MTT assay in monolayer cultures of normal human immunocompetent peripheral blood mononuclear cells (PBMC) that were either non-stimulated or stimulated to proliferate by mitogen phytohemagglutinin (PHA), as well as in human cervix adenocarcinoma cell (HeLa) cultures. Silver release kinetics and mechanical properties of nanocomposites were investigated under bioreactor conditions in the simulated body fluid (SBF) at 37°C. The release of silver was monitored under static conditions, and in two types of bioreactors: perfusion bioreactors and a bioreactor with dynamic compression coupled with SBF perfusion simulating in vivo conditions in articular cartilage. Ag/PVP nanocomposites exhibited slight cytotoxic effects against PBMC at the estimated concentration of 0.4 μmol dm(-3), with negligible variations observed amongst different cell cultures investigated. Studies of the silver release kinetics indicated internal diffusion as the rate limiting step, determined by statistically comparable results obtained at all investigated conditions. However, silver release rate was slightly higher in the bioreactor with dynamic compression coupled with SBF perfusion as compared to the other two systems indicating the influence of dynamic compression. Modelling of silver release kinetics revealed potentials for optimization of Ag/PVP nanocomposites for particular applications as wound dressings or soft tissue implants. Copyright © 2013 Elsevier B.V. All rights reserved.

Development and in vitro/in vivo Evaluation of a Silastic Intravaginal Ring for Mifepristone Delivery.

PubMed

Duan, X; Ning, M

2015-01-01

Preparation and in vitro/in vivo evaluation of mifepristone intravaginal ring formulations were investigated. In the present study, it is reported that a mifepristone intravaginal ring of reservoir design comprising of a mifepristone silicone elastomer core enclosed in a silicone layer. During the preparation of intravaginal ring solid dispersion method was employed which improved the release rate of drug from the intravaginal ring. In vitro release studies performed under sink conditions and the released drug amounts were estimated using UV spectrometry at 310 nm. In addition, the in vivo release profile of in-house devices was evaluated in female New Zealand white rabbits. The rabbit plasma samples were processed and analyzed using a validated HPLC-MS method. Norgestrel was used as internal standard, and plasma samples contained mifepristone and internal standard were deproteinized, and then subjected to HPLC-MS analysis under condition of electrospray ionization in the selected ion monitoring mode. The drug release from intravaginal ring made in house was constant for 21 days in rabbits, which suggested the mifepristone intravaginal ring release system would be useful in clinical practice in the future. The result indicated the in vitro/in vivo correlation is perfect, which explained in vitro release analysis method developed was feasible.

The biomechanics of javelin throwing: a review.

PubMed

Bartlett, R M; Best, R J

1988-01-01

In this paper, the scientific literature and that on the sports sciences relevant to javelin throwing is critically reviewed. This is particularly timely because of the change in the specification of the javelin for the men's event, which was introduced by the IAAF in 1986. A full discussion of the aerodynamics of the javelin is presented with due consideration of the change in pitching moment characteristics that the rules change had brought about. The uses and limitations of current computer programs for simulating javelin flight, in order to estimate optimal release parameters, are profiled. Consideration is also given to the effects of wind velocity, air density, javelin weight and the flutter and spin of the javelin on its flight. The review further considers the optimization of release parameters, drawing upon computer simulations and field-based data. The effects of release speed, release height, release angle, release angle of attack and release pitch rate are assessed. The javelin throwing technique is discussed in relation to cinematographically derived data, including an evaluation of experimental procedures. The importance to successful performance of the grip, the run-up and transition phases, the cross over and delivery strides are each reviewed. Finally, some prognoses as to the direction of future research into this complex throwing skill are offered.

Monitoring and Predicting the Long Distance Transport of Fusarium graminearum, Causal Agent of Fusarium Head Blight in Wheat and Barley

NASA Astrophysics Data System (ADS)

Prussin, Aaron Justin, II

Fusarium head blight (FHB), caused by Fusarium graminearum , is a serious disease of wheat and barley that has caused several billion dollars in crop losses over the last decade in the United States. Spores of F. graminearum are released from corn and small grain residues left-over from the previous growing season and are transported long distances in the atmosphere before being deposited. Current risk assessment tools consider environmental conditions favorable for disease development, but do not include spore transport. Long distance transport models have been proposed for a number of plant pathogens, but many of these models have not been experimentally validated. In order to predict the atmospheric transport of F. graminearum, the potential source strength ( Qpot) of inoculum must be known. We conducted a series of laboratory and field experiments to estimate Qpot from a field-scale source of inoculum of F. graminearum. Perithecia were generated on artificial (carrot agar) and natural (corn stalk) substrates. Artificial substrate (carrot agar) produced 15+/-0.4 perithecia cm-2, and natural substrate (corn stalk) produced 44+/-2 perithecia cm-2. Individual perithecia were excised from both substrate types and allowed to release ascospores every 24 hours. Perithecia generated from artificial (carrot agar) and natural (corn stalk) substrates released a mean of 104+/-5 and 276+/-16 ascospores, respectively. A volumetric spore trap was placed inside a 3,716 m2 clonal source of inoculum in 2011 and 2012. Results indicated that ascospores were released under field conditions predominantly (>90%) during the night (1900 to 0700 hours). Estimates of Qpot for our field-scale sources of inoculum were approximately 4 billion ascospores per 3,716 m 2. Release-recapture studies were conducted from a clonal field-scale source of F. graminearum in 2011 and 2012. Microsatellites were used to identify the released clone of F. graminearum at distances up to 1 km from the source. Dispersal kernels for field observations were compared to results predicted by a Gaussian dispersal-based spore transport model. In 2011 and 2012, dispersal kernel shape coefficients were similar for both results observed in the field and predicted by the model, with both being dictated by a power law function, indicating that turbulence was the dominant transport factor on the scale we studied (˜ 1 km). Model predictions had a stronger correlation with the number of spores being released when using a time varying q0 emission rate (r= 0.92 in 2011 and r= 0.84 in 2012) than an identical daily pattern q0 emission rate (r= 0.35 in 2011 and r= 0.32 in 2012). The actual numbers of spores deposited were 3 and 2000 times lower than predicted if Qpot were equal to the actual number of spores released in 2011 and 2012, respectively. Future work should address estimating the actual number of spore released from an inoculated field during any given season, to improve prediction accuracy of the model. This work should assist in improving current risk assessment tools for FHB and contribute to the development of early warning systems for the spread of F. graminearum.

Spent fuel radionuclide source-term model for assessing spent fuel performance in geological disposal. Part I: Assessment of the instant release fraction

NASA Astrophysics Data System (ADS)

Johnson, Lawrence; Ferry, Cécile; Poinssot, Christophe; Lovera, Patrick

2005-11-01

A source-term model for the short-term release of radionuclides from spent nuclear fuel (SNF) has been developed. It provides quantitative estimates of the fraction of various radionuclides that are expected to be released rapidly (the instant release fraction, or IRF) when water contacts the UO 2 or MOX fuel after container breaching in a geological repository. The estimates are based on correlation of leaching data for radionuclides with fuel burnup and fission gas release. Extrapolation of the data to higher fuel burnup values is based on examination of data on fuel restructuring, such as rim development, and on fission gas release data, which permits bounding IRF values to be estimated assuming that radionuclide releases will be less than fission gas release. The consideration of long-term solid-state changes influencing the IRF prior to canister breaching is addressed by evaluating alpha self-irradiation enhanced diffusion, which may gradually increase the accumulation of fission products at grain boundaries.

Wastewater treatment plant effluents as source of cosmetic polyethylene microbeads to freshwater.

PubMed

Kalčíková, G; Alič, B; Skalar, T; Bundschuh, M; Gotvajn, A Žgajnar

2017-12-01

Microplastics in the environment are either a product of the fractionation of larger plastic items or a consequence of the release of microbeads, which are ingredients of cosmetics, through wastewater treatment plant (WWTP) effluents. The aim of this study was to estimate the amount of microbeads that may be released by the latter pathways to surface waters using Ljubljana, Slovenia as a case study. For this purpose, microbeads contained in cosmetics were in a first step characterized for their physical properties and particle size distribution. Subsequently, daily emission of microbeads from consumers to the sewerage system, their fate in biological WWTPs and finally their release into surface waters were estimated for Ljubljana. Most of the particles found in cosmetic products were <100 μm. After application, microbeads are released into sewerage system at an average rate of 15.2 mg per person per day. Experiments using a lab-scale sequencing batch biological WWTP confirmed that on average 52% of microbeads are captured in activated sludge. Particle size analyses of the influent and effluent confirmed that smaller particles (up to 60-70 μm) are captured within activated sludge while bigger particles were detected in the effluent. Applying these data to the situation in Ljubljana indicates that about 112,500,000 particles may daily be released into the receiving river, resulting in a microbeads concentration of 21 particles/m 3 . Since polyethylene particles cannot be degraded and thus likely accumulate, the data raise concerns about potential effects in aquatic ecosystems in future. Copyright © 2017 Elsevier Ltd. All rights reserved.

As assessment of power system vulnerability to release of carbon fibers during commercial aviation accidents

NASA Technical Reports Server (NTRS)

Larocque, G. R.

1980-01-01

The vulnerability of a power distribution system in Bedford and Lexington, Massachusetts to power outages as a result of exposure to carbon fibers released in a commercial aviation accident in 1993 was examined. Possible crash scenarios at Logan Airport based on current operational data and estimated carbon fiber usage levels were used to predict exposure levels and occurrence probabilities. The analysis predicts a mean time between carbon fiber induced power outages of 2300 years with an expected annual consequence of 0.7 persons losing power. In comparison to historical outage data for the system, this represents a 0.007% increase in outage rate and 0.07% increase in consequence.

A novel method for estimating methane emissions from underground coal mines: The Yanma coal mine, China

NASA Astrophysics Data System (ADS)

Ji, Zhong-Min; Chen, Zhi-Jian; Pan, Jie-Nan; Niu, Qing-He

2017-12-01

As the world's largest coal producer and consumer, China accounts for a relatively high proportion of methane emissions from coal mines. Several estimation methods had been established for the coal mine methane (CMM) emission. However, with large regional differences, various reservoir formation types of coalbed methane (CBM) and due to the complicated geological conditions in China, these methods may be deficient or unsuitable for all the mining areas (e.g. Jiaozuo mining area). By combing the CMM emission characteristics and considering the actual situation of methane emissions from underground coal mine, we found that the methane pre-drainage is a crucial reason creating inaccurate evaluating results for most estimation methods. What makes it so essential is the extensive pre-drainage quantity and its irrelevance with annual coal production. Accordingly, the methane releases were divided into two categories: methane pre-drainage and methane release during mining. On this basis, a pioneering method for estimating CMM emissions was proposed. Taking the Yanma coal mine in the Jiaozuo mining area as a study case, the evaluation method of the pre-drainage methane quantity was established after the correlation analysis between the pre-drainage rate and time. Thereafter, the mining activity influence factor (MAIF) was first introduced to reflect the methane release from the coal and rock seams around where affected by mining activity, and the buried depth was adopted as the predictor of the estimation for future methane emissions. It was verified in the six coal mines of Jiaozuo coalfield (2011) that the new estimation method has the minimum errors of 12.11%, 9.23%, 5.77%, -5.20%, -8.75% and 4.92% respectively comparing with other methods. This paper gives a further insight and proposes a more accurate evaluation method for the CMM emissions, especially for the coal seams with low permeability and strong tectonic deformation in methane outburst coal mines.

First experiences with methods to measure ammonia emissions from naturally ventilated cattle buildings in the U.K.

NASA Astrophysics Data System (ADS)

Demmers, T. G. M.; Burgess, L. R.; Short, J. L.; Phillips, V. R.; Clark, J. A.; Wathes, C. M.

A method has been developed to measure the emission rate of ammonia from naturally ventilated U.K. livestock buildings. The method is based on measurements of ammonia concentration and estimates of the ventilation rate of the building by continuous release of carbon monoxide tracer within the building. The tracer concentration is measured at nine positions in openings around the perimeter of the building, as well as around a ring sampling line. Two criteria were evaluated to decide whether, at any given time, a given opening in the building acted as an air inlet or as an air outlet. Carbon monoxide concentration difference across an opening was found to be a better criterion than the temperature difference across the opening. Ammonia concentrations were measured continuously at the sampling points using a chemiluminescence analyser. The method was applied to a straw-bedded beef unit and to a slurry-based dairy unit. Both buildings were of space-boarded construction. Ventilation rates estimated by the ring line sample were consistently higher than by the perimeter samples. During calm weather, the ventilation estimates by both samples were similar (10-20 air changes h -1). However, during windy conditions (>5 m s -1) the ventilation rate was overestimated by the ring line sample (average 100 air changes h -1) compared to the perimeter samples (average 50 air changes h -1). The difference was caused by incomplete mixing of the tracer within the building. The ventilation rate estimated from the perimeter samples was used for the calculation of the emission rate. Preliminary estimates of the ammonia emission factor were 6.0 kg NH 3 (500 kg live-weight) -1 (190 d) -1 for the slurry-based dairy unit and 3.7 for the straw-bedded beef unit.

ANEMOS: A computer code to estimate air concentrations and ground deposition rates for atmospheric nuclides emitted from multiple operating sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, C.W.; Sjoreen, A.L.; Begovich, C.L.

This code estimates concentrations in air and ground deposition rates for Atmospheric Nuclides Emitted from Multiple Operating Sources. ANEMOS is one component of an integrated Computerized Radiological Risk Investigation System (CRRIS) developed for the US Environmental Protection Agency (EPA) for use in performing radiological assessments and in developing radiation standards. The concentrations and deposition rates calculated by ANEMOS are used in subsequent portions of the CRRIS for estimating doses and risks to man. The calculations made in ANEMOS are based on the use of a straight-line Gaussian plume atmospheric dispersion model with both dry and wet deposition parameter options. Themore » code will accommodate a ground-level or elevated point and area source or windblown source. Adjustments may be made during the calculations for surface roughness, building wake effects, terrain height, wind speed at the height of release, the variation in plume rise as a function of downwind distance, and the in-growth and decay of daughter products in the plume as it travels downwind. ANEMOS can also accommodate multiple particle sizes and clearance classes, and it may be used to calculate the dose from a finite plume of gamma-ray-emitting radionuclides passing overhead. The output of this code is presented for 16 sectors of a circular grid. ANEMOS can calculate both the sector-average concentrations and deposition rates at a given set of downwind distances in each sector and the average of these quantities over an area within each sector bounded by two successive downwind distances. ANEMOS is designed to be used primarily for continuous, long-term radionuclide releases. This report describes the models used in the code, their computer implementation, the uncertainty associated with their use, and the use of ANEMOS in conjunction with other codes in the CRRIS. A listing of the code is included in Appendix C.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spriggs, G D

In a previous paper, the composite exposure rate conversion factor (ECF) for nuclear fallout was calculated using a simple theoretical photon-transport model. The theoretical model was used to fill in the gaps in the FGR-12 table generated by ORNL. The FGR-12 table contains the individual conversion factors for approximate 1000 radionuclides. However, in order to calculate the exposure rate during the first 30 minutes following a nuclear detonation, the conversion factors for approximately 2000 radionuclides are needed. From a human-effects standpoint, it is also necessary to have the dose rate conversion factors (DCFs) for all 2000 radionuclides. The DCFs aremore » used to predict the whole-body dose rates that would occur if a human were standing in a radiation field of known exposure rate. As calculated by ORNL, the whole-body dose rate (rem/hr) is approximately 70% of the exposure rate (R/hr) at one meter above the surface. Hence, the individual DCFs could be estimated by multiplying the individual ECFs by 0.7. Although this is a handy rule-of-thumb, a more consistent (and perhaps, more accurate) method of estimating the individual DCFs for the missing radionuclides in the FGR-12 table is to use the linear relationship between DCF and total gamma energy released per decay. This relationship is shown in Figure 1. The DCFs for individual organs in the body can also be estimated from the estimated whole-body DCF. Using the DCFs given FGR-12, the ratio of the organ-specific DCFs to the whole-body DCF were plotted as a function of the whole-body DCF. From these plots, the asymptotic ratios were obtained (see Table 1). Using these asymptotic ratios, the organ-specific DCFs can be estimated using the estimated whole-body DCF for each of the missing radionuclides in the FGR-12 table. Although this procedure for estimating the organ-specific DCFs may over-estimate the value for some low gamma-energy emitters, having a finite value for the organ-specific DCFs in the table is probably better than having no value at all. A summary of the complete ECF and DCF values are given in Table 2.« less

Possible effects of volcanic eruptions on stratospheric minor constituent chemistry

NASA Technical Reports Server (NTRS)

Stolarski, R. S.; Butler, D. M.

1979-01-01

Although stratosphere penetrating volcanic eruptions have been infrequent during the last half century, periods have existed in the last several hundred years when such eruptions were significantly more frequent. Several mechanisms exist for these injections to affect stratospheric minor constituent chemistry, both on the long-term average and for short-term perturbations. These mechanisms are reviewed and, because of the sensitivity of current models of stratospheric ozone to chlorine perturbations, quantitative estimates are made of chlorine injection rates. It is found that, if chlorine makes up as much as 0.5 to 1% of the gases released and if the total gases released are about the same magnitude as the fine ash, then a major stratosphere penetrating eruption could deplete the ozone column by several percent. The estimate for the Agung eruption of 1963 is just under 1% an amount not excluded by the ozone record but complicated by the peak in atmospheric nuclear explosions at about the same time.

Estimates of Radioxenon Released from Southern Hemisphere Medical isotope Production Facilities Using Measured Air Concentrations and Atmospheric Transport Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eslinger, Paul W.; Friese, Judah I.; Lowrey, Justin D.

2014-09-01

Abstract The International Monitoring System (IMS) of the Comprehensive-Nuclear-Test-Ban-Treaty monitors the atmosphere for radioactive xenon leaking from underground nuclear explosions. Emissions from medical isotope production represent a challenging background signal when determining whether measured radioxenon in the atmosphere is associated with a nuclear explosion prohibited by the treaty. The Australian Nuclear Science and Technology Organisation (ANSTO) operates a reactor and medical isotope production facility in Lucas Heights, Australia. This study uses two years of release data from the ANSTO medical isotope production facility and Xe-133 data from three IMS sampling locations to estimate the annual releases of Xe-133 from medicalmore » isotope production facilities in Argentina, South Africa, and Indonesia. Atmospheric dilution factors derived from a global atmospheric transport model were used in an optimization scheme to estimate annual release values by facility. The annual releases of about 6.8×1014 Bq from the ANSTO medical isotope production facility are in good agreement with the sampled concentrations at these three IMS sampling locations. Annual release estimates for the facility in South Africa vary from 1.2×1016 to 2.5×1016 Bq and estimates for the facility in Indonesia vary from 6.1×1013 to 3.6×1014 Bq. Although some releases from the facility in Argentina may reach these IMS sampling locations, the solution to the objective function is insensitive to the magnitude of those releases.« less

An algal carbon budget for pelagic-benthic coupling in Lake Michigan

USGS Publications Warehouse

Fitzgerald, S.A.; Gardner, W.S.

1993-01-01

Assimilation and respiration rates of Diporeia sp., an abundant benthic amphipod, and of sediment microheterotrophs were measured in a microcosm study. Release of radioisotope in the form of dissolved organic compounds was much lower than that incorporated and respired for both Diporeia and sediment bacteria. Of the 61 mmol C m-2 of algal C estimated to be deposited during the spring bloom. -from Authors

Vital Signs: Health Burden and Medical Costs of Nonfatal Injuries to Motor Vehicle Occupants — United States, 2012

PubMed Central

Bergen, Gwen; Peterson, Cora; Ederer, David; Florence, Curtis; Haileyesus, Tadesse; Kresnow, Marcie-jo; Xu, Likang

2014-01-01

Background Motor vehicle crashes are a leading cause of death and injury in the United States. The purpose of this study was to describe the current health burden and medical and work loss costs of nonfatal crash injuries among vehicle occupants in the United States. Methods CDC analyzed data on emergency department (ED) visits resulting from nonfatal crash injuries among vehicle occupants in 2012 using the National Electronic Injury Surveillance System – All Injury Program (NEISS-AIP) and the Healthcare Cost and Utilization Project National Inpatient Sample (HCUP-NIS). The number and rate of all ED visits for the treatment of crash injuries that resulted in the patient being released and the number and rate of hospitalizations for the treatment of crash injuries were estimated, as were the associated number of hospital days and lifetime medical and work loss costs. Results In 2012, an estimated 2,519,471 ED visits resulted from nonfatal crash injuries, with an estimated lifetime medical cost of $18.4 billion (2012 U.S. dollars). Approximately 7.5% of these visits resulted in hospitalizations that required an estimated 1,057,465 hospital days in 2012. Conclusions Nonfatal crash injuries occur frequently and result in substantial costs to individuals, employers, and society. For each motor vehicle crash death in 2012, eight persons were hospitalized, and 100 were treated and released from the ED. Implications for Public Health Public health practices and laws, such as primary seat belt laws, child passenger restraint laws, ignition interlocks to prevent alcohol impaired driving, sobriety checkpoints, and graduated driver licensing systems have demonstrated effectiveness for reducing motor vehicle crashes and injuries. They might also substantially reduce associated ED visits, hospitalizations, and medical costs. PMID:25299606

Characterizing the early life history of an imperiled freshwater mussel (Ptychobranchus jonesi) with host-fish determination and fecundity estimation

USGS Publications Warehouse

Mcleod, John; Jelks, Howard L.; Pursifull, Sandra; Johnson, Nathan A.

2017-01-01

Conservation of imperiled species is frequently challenged by insufficient knowledge of life history and environmental factors that affect various life stages. The larvae (glochidia) of most freshwater mussels in the family Unionidae are obligate ectoparasites of fishes. We described the early life history of the federally endangered Southern Kidneyshell Ptychobranchus jonesi and compared methods for estimating fecundity and conducting host trials on this conglutinate-producing mussel species. Glochidial inoculation baths and direct feeding of conglutinates to Percina nigrofasciata, Etheostoma edwini, and Etheostoma fusiforme resulted in successful metamorphosis to the juvenile life stage. Ptychobranchus jonesi glochidia did not metamorphose on 25 other species of fishes tested representing 11 families. Three juveniles were recovered from Gambusia holbrooki resulting in a metamorphosis rate <1%. We characterize P. jonesi as a host-fish specialist that fractionally releases conglutinates from late January to early June. Intact P. jonesi conglutinates resemble simuliid fly larvae attached to an egg-like structure, but most conglutinates were released as segments representing separate egg or larva mimics. Viability of glochidia encased within a conglutinate was >90% for ≥5 d. Feeding conglutinates directly to fishes allowed us to estimate seminatural infestation rates and calculate average numbers of juveniles produced per conglutinate, unlike the traditional approach of infesting fish hosts in an inoculation bath. Regressions based on the physical dimensions of each conglutinate or conglutinate segment were the most practical method used to estimate fecundity. Species distribution information, early life-history description, and methods developed for determining fecundity and conducting host trials may assist in the conservation of P. jonesi during recovery options that include captive propagation, augmentation, and reestablishment.

Fire carbon emissions over maritime southeast Asia in 2015 largest since 1997.

PubMed

Huijnen, V; Wooster, M J; Kaiser, J W; Gaveau, D L A; Flemming, J; Parrington, M; Inness, A; Murdiyarso, D; Main, B; van Weele, M

2016-05-31

In September and October 2015 widespread forest and peatland fires burned over large parts of maritime southeast Asia, most notably Indonesia, releasing large amounts of terrestrially-stored carbon into the atmosphere, primarily in the form of CO2, CO and CH4. With a mean emission rate of 11.3 Tg CO2 per day during Sept-Oct 2015, emissions from these fires exceeded the fossil fuel CO2 release rate of the European Union (EU28) (8.9 Tg CO2 per day). Although seasonal fires are a frequent occurrence in the human modified landscapes found in Indonesia, the extent of the 2015 fires was greatly inflated by an extended drought period associated with a strong El Niño. We estimate carbon emissions from the 2015 fires to be the largest seen in maritime southeast Asia since those associated with the record breaking El Niño of 1997. Compared to that event, a much better constrained regional total carbon emission estimate can be made for the 2015 fires through the use of present-day satellite observations of the fire's radiative power output and atmospheric CO concentrations, processed using the modelling and assimilation framework of the Copernicus Atmosphere Monitoring Service (CAMS) and combined with unique in situ smoke measurements made on Kalimantan.

Predation by northern pikeminnow on juvenile salmonids in The Dalles Dam tailrace: field, laboratory, and habitat modeling studies (FY2000)

USGS Publications Warehouse

Petersen, James H.; Barfoot, Craig A.; Sheer, Mindi B.

2001-01-01

Predation by resident fish is known to be a substantial cause of juvenile salmonid mortality, especially in dam tailraces and outfall locations. Conditions in The Dalles Dam tailrace are unique compared to other projects on the Columbia or Snake rivers, having a complex basin with a series of downriver islands where predators are known to reside. In May-June of 1999, northern pikeminnow and smallmouth bass were sampled in the tailrace of The Dalles Dam during periods immediately following the release of PIT-tagged juvenile salmonids for survival studies. Over twice as many smallmouth bass (N = 101) were collected as northern pikeminnow (N = 40), but none of the predators had PIT tags within their gut. A laboratory study was conducted to estimate the time required for PIT tags in juvenile salmonids to be evacuated from the gut of northern pikeminnow after consuming a tagged preyfish. Evacuation rate was sensitive to temperature, with median evacuation time being 21 h at 18 oC and 30 h at 14 oC. These results suggest that field studies to estimate predator population sizes, feeding rates, or predation on specific release groups would require considerably more effort than we allocated during 1999.

Fire carbon emissions over maritime southeast Asia in 2015 largest since 1997

NASA Astrophysics Data System (ADS)

Huijnen, V.; Wooster, M. J.; Kaiser, J. W.; Gaveau, D. L. A.; Flemming, J.; Parrington, M.; Inness, A.; Murdiyarso, D.; Main, B.; van Weele, M.

2016-05-01

In September and October 2015 widespread forest and peatland fires burned over large parts of maritime southeast Asia, most notably Indonesia, releasing large amounts of terrestrially-stored carbon into the atmosphere, primarily in the form of CO2, CO and CH4. With a mean emission rate of 11.3 Tg CO2 per day during Sept-Oct 2015, emissions from these fires exceeded the fossil fuel CO2 release rate of the European Union (EU28) (8.9 Tg CO2 per day). Although seasonal fires are a frequent occurrence in the human modified landscapes found in Indonesia, the extent of the 2015 fires was greatly inflated by an extended drought period associated with a strong El Niño. We estimate carbon emissions from the 2015 fires to be the largest seen in maritime southeast Asia since those associated with the record breaking El Niño of 1997. Compared to that event, a much better constrained regional total carbon emission estimate can be made for the 2015 fires through the use of present-day satellite observations of the fire’s radiative power output and atmospheric CO concentrations, processed using the modelling and assimilation framework of the Copernicus Atmosphere Monitoring Service (CAMS) and combined with unique in situ smoke measurements made on Kalimantan.

Fire carbon emissions over maritime southeast Asia in 2015 largest since 1997

PubMed Central

Huijnen, V.; Wooster, M. J.; Kaiser, J. W.; Gaveau, D. L. A.; Flemming, J.; Parrington, M.; Inness, A.; Murdiyarso, D.; Main, B.; van Weele, M.

2016-01-01

In September and October 2015 widespread forest and peatland fires burned over large parts of maritime southeast Asia, most notably Indonesia, releasing large amounts of terrestrially-stored carbon into the atmosphere, primarily in the form of CO2, CO and CH4. With a mean emission rate of 11.3 Tg CO2 per day during Sept-Oct 2015, emissions from these fires exceeded the fossil fuel CO2 release rate of the European Union (EU28) (8.9 Tg CO2 per day). Although seasonal fires are a frequent occurrence in the human modified landscapes found in Indonesia, the extent of the 2015 fires was greatly inflated by an extended drought period associated with a strong El Niño. We estimate carbon emissions from the 2015 fires to be the largest seen in maritime southeast Asia since those associated with the record breaking El Niño of 1997. Compared to that event, a much better constrained regional total carbon emission estimate can be made for the 2015 fires through the use of present-day satellite observations of the fire’s radiative power output and atmospheric CO concentrations, processed using the modelling and assimilation framework of the Copernicus Atmosphere Monitoring Service (CAMS) and combined with unique in situ smoke measurements made on Kalimantan. PMID:27241616

Criminal recidivism in sexual homicide perpetrators.

PubMed

Hill, Andreas; Habermann, Niels; Klusmann, Dietrich; Berner, Wolfgang; Briken, Peer

2008-02-01

Forensic psychiatric reports on 166 sexual homicide perpetrators in Germany were retrospectively analyzed for criminal risk factors. Follow-up information about release and reconvictions from federal criminal records was available for 139 offenders; 90 (64.7%) had been released. The estimated recidivism rate (Kaplan-Meier analyses) for 20 years at risk was 23.1% for sexual and 18.3% for nonsexual violent reoffences. Three men (3.3%) were reconvicted for attempted or completed homicide. Only young age at the time of sexual homicide resulted in higher sexual recidivism, whereas increased nonsexual violent recidivism was related to previous sexual and nonsexual delinquency, psychopathic symptoms, and higher scores in risk assessment instruments. Increased recidivism with any violent reoffence was associated with age-related factors: young age at first sexual offence, at homicide, and at release and duration of detention. The impacts of the results for risk assessment, relapse prevention, and supervision are discussed.

Fire danger rating over Mediterranean Europe based on fire radiative power derived from Meteosat

NASA Astrophysics Data System (ADS)

Pinto, Miguel M.; DaCamara, Carlos C.; Trigo, Isabel F.; Trigo, Ricardo M.; Feridun Turkman, K.

2018-02-01

We present a procedure that allows the operational generation of daily forecasts of fire danger over Mediterranean Europe. The procedure combines historical information about radiative energy released by fire events with daily meteorological forecasts, as provided by the Satellite Application Facility for Land Surface Analysis (LSA SAF) and the European Centre for Medium-Range Weather Forecasts (ECMWF). Fire danger is estimated based on daily probabilities of exceedance of daily energy released by fires occurring at the pixel level. Daily probability considers meteorological factors by means of the Canadian Fire Weather Index (FWI) and is estimated using a daily model based on a generalized Pareto distribution. Five classes of fire danger are then associated with daily probability estimated by the daily model. The model is calibrated using 13 years of data (2004-2016) and validated against the period of January-September 2017. Results obtained show that about 72 % of events releasing daily energy above 10 000 GJ belong to the extreme class of fire danger, a considerably high fraction that is more than 1.5 times the values obtained when using the currently operational Fire Danger Forecast module of the European Forest Fire Information System (EFFIS) or the Fire Risk Map (FRM) product disseminated by the LSA SAF. Besides assisting in wildfire management, the procedure is expected to help in decision making on prescribed burning within the framework of agricultural and forest management practices.

How to estimate green house gas (GHG) emissions from an excavator by using CAT's performance chart

NASA Astrophysics Data System (ADS)

Hajji, Apif M.; Lewis, Michael P.

2017-09-01

Construction equipment activities are a major part of many infrastructure projects. This type of equipment typically releases large quantities of green house gas (GHG) emissions. GHG emissions may come from fuel consumption. Furthermore, equipment productivity affects the fuel consumption. Thus, an estimating tool based on the construction equipment productivity rate is able to accurately assess the GHG emissions resulted from the equipment activities. This paper proposes a methodology to estimate the environmental impact for a common construction activity. This paper delivers sensitivity analysis and a case study for an excavator based on trench excavation activity. The methodology delivered in this study can be applied to a stand-alone model, or a module that is integrated with other emissions estimators. The GHG emissions are highly correlated to diesel fuel use, which is approximately 10.15 kilograms (kg) of CO2 per gallon of diesel fuel. The results showed that the productivity rate model as the result from multiple regression analysis can be used as the basis for estimating GHG emissions, and also as the framework for developing emissions footprint and understanding the environmental impact from construction equipment activities introduction.

Source Term Estimation of Radioxenon Released from the Fukushima Dai-ichi Nuclear Reactors Using Measured Air Concentrations and Atmospheric Transport Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eslinger, Paul W.; Biegalski, S.; Bowyer, Ted W.

2014-01-01

Systems designed to monitor airborne radionuclides released from underground nuclear explosions detected radioactive fallout from the Fukushima Daiichi nuclear accident in March 2011. Atmospheric transport modeling (ATM) of plumes of noble gases and particulates were performed soon after the accident to determine plausible detection locations of any radioactive releases to the atmosphere. We combine sampling data from multiple International Modeling System (IMS) locations in a new way to estimate the magnitude and time sequence of the releases. Dilution factors from the modeled plume at five different detection locations were combined with 57 atmospheric concentration measurements of 133-Xe taken from Marchmore » 18 to March 23 to estimate the source term. This approach estimates that 59% of the 1.24×1019 Bq of 133-Xe present in the reactors at the time of the earthquake was released to the atmosphere over a three day period. Source term estimates from combinations of detection sites have lower spread than estimates based on measurements at single detection sites. Sensitivity cases based on data from four or more detection locations bound the source term between 35% and 255% of available xenon inventory.« less

Simultaneous use of mark-recapture and radiotelemetry to estimate survival, movement, and capture rates

USGS Publications Warehouse

Powell, L.A.; Conroy, M.J.; Hines, J.E.; Nichols, J.D.; Krementz, D.G.

2000-01-01

Biologists often estimate separate survival and movement rates from radio-telemetry and mark-recapture data from the same study population. We describe a method for combining these data types in a single model to obtain joint, potentially less biased estimates of survival and movement that use all available data. We furnish an example using wood thrushes (Hylocichla mustelina) captured at the Piedmont National Wildlife Refuge in central Georgia in 1996. The model structure allows estimation of survival and capture probabilities, as well as estimation of movements away from and into the study area. In addition, the model structure provides many possibilities for hypothesis testing. Using the combined model structure, we estimated that wood thrush weekly survival was 0.989 ? 0.007 ( ?SE). Survival rates of banded and radio-marked individuals were not different (alpha hat [S_radioed, ~ S_banded]=log [S hat _radioed/ S hat _banded]=0.0239 ? 0.0435). Fidelity rates (weekly probability of remaining in a stratum) did not differ between geographic strata (psi hat=0.911 ? 0.020; alpha hat [psi11, psi22]=0.0161 ? 0.047), and recapture rates ( = 0.097 ? 0.016) banded and radio-marked individuals were not different (alpha hat [p_radioed, p_banded]=0.145 ? 0.655). Combining these data types in a common model resulted in more precise estimates of movement and recapture rates than separate estimation, but ability to detect stratum or mark-specific differences in parameters was week. We conducted simulation trials to investigate the effects of varying study designs on parameter accuracy and statistical power to detect important differences. Parameter accuracy was high (relative bias [RBIAS] <2 %) and confidence interval coverage close to nominal, except for survival estimates of banded birds for the 'off study area' stratum, which were negatively biased (RBIAS -7 to -15%) when sample sizes were small (5-10 banded or radioed animals 'released' per time interval). To provide adequate data for useful inference from this model, study designs should seek a minimum of 25 animals of each marking type observed (marked or observed via telemetry) in each time period and geographic stratum.

Role of voltage-sensitive receptors in nicotinic transmission.

PubMed Central

Lester, H A; Koblin, D D; Sheridan, R E

1978-01-01

This paper compares the conductance induced by bath-applied acetyl-choline (ACh) and by the same transmitter released from nerve terminals at Electrophorus electroplaques. For the former case, dose-response relations are characterized by the maximal agonist-induced conductance, rgamma (130 mmho/cm2), and by the concentration which induces half this conductance; this concentration is termed Kapp and equals 50 micron at -85 mV. For the latter case, neurally evoked postsynaptic currents (PSCs) are characterized by the peak conductance during strongly facilitated release, gPSC, and by the rate constant for decay, alpha. Since gPSC roughly equals rgamma, it is concluded that the PSC activates nearly all available receptor channels. These and other data agree with recent estimates that during the growth phase of the quantal response, (a) the ACh concentration is at least several hundred micromolar; and (b) most nearby channels are activated. However both alpha and Kapp increase during depolarization, at a rate of about e-fold per 86 mV. These observations on voltage sensitivity suggest that a suprathreshold synaptic event is rapidly terminated because the action potential abruptly releases ACh molecules from receptors. PMID:630039

Petroleum Source Rock Maturation Data Constrain Predictions of Natural Hydrocarbon Seepage into the Atmosphere

NASA Astrophysics Data System (ADS)

Mansfield, M. L.

2013-12-01

Natural seepage of methane from the lithosphere to the atmosphere occurs in regions with large natural gas deposits. According to some authors, it accounts for roughly 5% of the global methane budget. I explore a new approach to estimate methane fluxes based on the maturation of kerogen, which is the hydrocarbon polymer present in petroleum source rocks, and whose pyrolysis leads to the formation of oil and natural gas. The temporal change in the atomic H/C ratio of kerogen lets us estimate the total carbon mass released by it in the form of oil and natural gas. Then the time interval of active kerogen pyrolysis lets us estimate the average annual formation rate of oil and natural gas in any given petroleum system. Obviously, this is an upper bound to the average annual rate at which natural gas seeps into the atmosphere. After adjusting for bio-oxidation of natural gas, I conclude that the average annual seepage rate in the Uinta Basin of eastern Utah is not greater than (3100 × 900) tonne/y. This is (0.5 × 0.15)% of the total flux of methane into the atmosphere over the Basin, as measured during aircraft flights. I speculate about the difference between the regional 0.5% and the global 5% estimates.

Constraining estimates of methane emissions from Arctic permafrost regions with CARVE

NASA Astrophysics Data System (ADS)

Chang, R. Y.; Karion, A.; Sweeney, C.; Henderson, J.; Mountain, M.; Eluszkiewicz, J.; Luus, K. A.; Lin, J. C.; Dinardo, S.; Miller, C. E.; Wofsy, S. C.

2013-12-01

Permafrost in the Arctic contains large carbon pools that are currently non-labile, but can be released to the atmosphere as polar regions warm. In order to predict future climate scenarios, we need to understand the emissions of these greenhouse gases under varying environmental conditions. This study presents in-situ measurements of methane made on board an aircraft during the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE), which sampled over the permafrost regions of Alaska. Using measurements from May to September 2012, seasonal emission rate estimates of methane from tundra are constrained using the Stochastic Time-Inverted Lagrangian Transport model, a Lagrangian particle dispersion model driven by custom polar-WRF fields. Preliminary results suggest that methane emission rates have not greatly increased since the Arctic Boundary Layer Experiment conducted in southwest Alaska in 1988.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ploskey, Gene R.; Faber, Derrek M.; Weiland, Mark A.

The purpose of this study was to estimate the survival for yearling Chinook salmon and steelhead smolts during spring 2010 in a portion of the Columbia River that includes Bonneville Dam. The study estimated smolt survival from a virtual release at Bonneville Dam to a survival array 81 km downstream of Bonneville Dam. We also estimated median forebay residence time, median tailrace egress time, and spill passage efficiency (SPE), as required in the Columbia Basin Fish Accords. A single release design was used to estimate survival from Bonneville Dam to a primary array located 81 km downstream of Bonneville. Themore » approach did not include a reference tailrace release. Releases of acoustic-tagged smolts above John Day Dam to Hood River contributed to the formation of virtual releases at a Bonneville Dam forebay entrance array and at the face of the dam. A total of 3,880 yearling Chinook salmon and 3,885 steelhead smolts were tagged and released in the investigation. The Juvenile Salmon Acoustic Telemetry System (JSATS) tag model number ATS-156dB, weighing 0.438 g in air, was used in this investigation.« less

Pandemic influenza-implications for critical care resources in Australia and New Zealand.

PubMed

Anderson, Therese A; Hart, Graeme K; Kainer, Marion A

2003-09-01

To quantify resource requirements (additional beds and ventilator capacity), for critical care services in the event of pandemic influenza. Cross-sectional survey about existing and potential critical care resources. Participants comprised 156 of the 176 Australasian (Australia and New Zealand) critical care units on the database of the Australian and New Zealand Intensive Care Society (ANZICS) Research Centre for Critical Care Resources. The Meltzer, Cox and Fukuda model was adapted to map a range of influenza attack rate estimates for hospitalisation and episodes likely to require intensive care and to predict critical care admission rates and bed day requirements. Estimations of ventilation rates were based on those for community-acquired pneumonia. The estimated extra number of persons requiring hospitalisation ranged from 8,455 (10% attack rate) to 150,087 (45% attack rate). The estimated number of additional admissions to critical care units ranged from 423 (5% admission rate, 10% attack rate) to 37,522 (25% admission rate, 45% attack rate). The potential number of required intensive care bed days ranged from 846 bed days (2 day length of stay, 10% attack rate) to 375,220 bed days (10 day length of stay, 45% attack rate). The number of persons likely to require mechanical ventilation ranged from 106 (25% of projected critical care admissions, 10% attack rate) to 28,142 (75% of projected critical care admissions, 45% attack rate). An additional 1,195 emergency ventilator beds were identified in public sector and 248 in private sector hospitals. Cancellation of elective surgery could release a potential 76,402 intensive care bed days (per annum), but in the event of pandemic influenza, 31,150 bed days could be required over an 8- to 12-week period. Australasian critical care services would be overwhelmed in the event of pandemic influenza. More work is required in relation to modelling, contingency plans, and resource allocation.

CrossWater - Modelling micropollutant loads from different sources in the Rhine basin

NASA Astrophysics Data System (ADS)

Moser, Andreas; Bader, Hans-Peter; Fenicia, Fabrizio; Scheidegger, Ruth; Stamm, Christian

2015-04-01

The contamination of fresh surface waters with micropollutants originating from various sources is a growing environmental issue. The challenges for an effective political regulation are numerous, particularly for international water basins. One prerequisite for effective management is the knowledge of water quality across different parts of a basin. In this study within the Rhine basin, the spatial patterns of micropollutant loads and concentrations from different use classes are investigated with a mass flow analysis and compared to the established territorial jurisdictions on micropollutants and water quality. The source area of micropollutants depends on the specific use of a compound. The focus of this study is on i) herbicides from agricultural landuse, ii) biocides from material protection on buildings and iii) human pharmaceuticals from households. The total mass of micropollutants available for release to the stream network is estimated based on statistical application and consumption data. Based on GIS data of agricultural landuse, vector data of buildings, wastewater treatment plant (WWTP) locations, respectively, the available mass of micropollutants is spatially distributed to the catchment areas. The actual release of micropollutants to the stream network is calculated with empirical loss rates related to river discharge for agricultural herbicides and to precipitation for biocides. For the pharmaceuticals the release is coupled to the metabolism rates and elimination rates in WWTP. For a first approximation national sales are downscaled to the catchment level to specify the available mass for selected model compounds (agricultural herbicides: Isoproturon, biocides: Carbendazim, human pharmaceuticals: Carbamazepine and Diclofenac). The available mass of herbicides and biocides is multiplied with empirical loss rates independent from discharge or precipitation to calculate the loads. The release of the pharmaceuticals was calculated by multiplying average consumption numbers with the person equivalent of the WWTP and the elimination rates. The comparison of pollutant loads to 7-day composite samples of all compounds at 15 locations along the Rhine yield plausible results.

Organically bound tritium (OBT) for various plants in the vicinity of a continuous atmospheric tritium release.

PubMed

Vichot, L; Boyer, C; Boissieux, T; Losset, Y; Pierrat, D

2008-10-01

In order to quantify tritium impact on the environmental, we studied vegetation continuously exposed to a tritiated atmosphere. We chose lichens as bio-indicators, trees for determination of past tritium releases of the Valduc Centre, and lettuce as edible vegetables for dose calculation regarding neighbourhood. The Pasquill and Doury models from the literature were tested to estimate tritium concentration in the air around vegetable for distance from the release point less than 500 m. The results in tree rings show that organically bound tritium (OBT) concentration was strongly correlated with tritium releases. Using the GASCON model, the modelled variation of OBT concentration with distance was correlated with the measurements. Although lichens are recognized as bio-indicators, our experiments show that they were not convenient for environmental surveys because their age is not definitive. Thus, tritium integration time cannot be precisely determined. Furthermore, their biological metabolism is not well known and tritium concentration appears to be largely dependent on species. An average conversion rate of HTO to OBT was determined for lettuce of about 0.20-0.24% h(-1). Nevertheless, even if it is equivalent to values already published in the literature for other vegetation, we have shown that this conversion rate, established by weekly samples, varies by a factor of 10 during the different stages of lettuce development, and that its variation is linked to the biomass derivative.

Release of chemical permeation enhancers from drug-in-adhesive transdermal patches.

PubMed

Qvist, Michael H; Hoeck, Ulla; Kreilgaard, Bo; Madsen, Flemming; Frokjaer, Sven

2002-01-14

There is only limited knowledge of how chemical permeation enhancers release from transdermal drug delivery systems of the drug-in-adhesive type. In this study, the release of eight commonly known enhancers from eight types of polymer adhesives was evaluated using Franz diffusion cells. It was shown that all the enhancers released completely from the adhesives and followed a square root of time kinetic (Higuchi law). Using a statistical analysis it was shown that the release rate was more dependent on the type of enhancer than on the type of polymers. The mean release rates were in the range from 2.2 to 11.1%/ radical t for the slowest and fastest releasing enhancers, which correspond to a 50% release within 500 and 20 min, respectively. Furthermore, the release rates were inversely proportional to the cube root of the molal volumes of the enhancers and to their logarithmic partition coefficients between the polymer adhesive and the receptor fluid. It was found that the observed release rates were probably due to a high diffusion coefficient of the enhancers rather than due to an inhomogeneous embedment of the enhancers in the adhesives. The type of adhesive showed minor influence on the release rate, especially among the acrylic polymers no difference was seen. However, compared to the acrylic adhesives, the polyisobutylene adhesive showed slower release rates, while the silicone adhesive showed slightly faster release rates.

Pilot randomised controlled trial of the ENGAGER collaborative care intervention for prisoners with common mental health problems, near to and after release.

PubMed

Lennox, Charlotte; Kirkpatrick, Tim; Taylor, Rod S; Todd, Roxanne; Greenwood, Clare; Haddad, Mark; Stevenson, Caroline; Stewart, Amy; Shenton, Deborah; Carroll, Lauren; Brand, Sarah L; Quinn, Cath; Anderson, Rob; Maguire, Mike; Harris, Tirril; Shaw, Jennifer; Byng, Richard

2018-01-01

Rates of common mental health problems are much higher in prison populations, but access to primary care mental health support falls short of community equivalence. Discontinuity of care on release is the norm and is further complicated by substance use and a range of social problems, e.g. homelessness. To address these problems, we worked with criminal justice, third sector social inclusion services, health services and people with lived experiences (peer researchers), to develop a complex collaborative care intervention aimed at supporting men with common mental health problems near to and following release from prison. This paper describes an external pilot trial to test the feasibility of a full randomised controlled trial. Eligible individuals with 4 to 16 weeks left to serve were screened to assess for common mental health problems. Participants were then randomised at a ratio of 2:1 allocation to ENGAGER plus standard care (intervention) or standard care alone (treatment as usual). Participants were followed up at 1 and 3 months' post release. Success criteria for this pilot trial were to meet the recruitment target sample size of 60 participants, to follow up at least 50% of participants at 3 months' post release from prison, and to deliver the ENGAGER intervention. Estimates of recruitment and retention rates and 95% confidence intervals (CIs) are reported. Descriptive analyses included summaries (percentages or means) for participant demographics, and baseline characteristics are reported. Recruitment target was met with 60 participants randomised in 9 months. The average retention rates were 73% at 1 month [95% CI 61 to 83] and 47% at 3 months follow-up [95% CI 35 to 59]. Ninety percent of participants allocated to the intervention successfully engaged with a practitioner before release and 70% engaged following release. This pilot confirms the feasibility of conducting a randomised trial for prison leavers with common mental health problems. Based on this pilot study and some minor changes to the trial design and intervention, a full two-centre randomised trial assessing the clinical and cost-effectiveness of the ENGAGER intervention is currently underway.

Release of Oxidized Bromine Species From Diatoms: Implication for the Polar Troposphere and Oceanic Polyhalomethane Production

NASA Astrophysics Data System (ADS)

Manley, S. L.; Hill, V. L.

2006-12-01

Marine and ice diatoms are known producers of polybromomethanes. These trace gases produced from ice algae have been implicated as a source of photochemically active bromine involved in polar surface ozone depletion events. A more dominant source of reactive bromine, however, has been attributed to the reaction on ice particles and in sea spray aerosols of atmospherically derived HOBr with bromide and chloride to produce the dihalogens Br2 and BrCl. We have measured the release of oxidized bromine species (Brox = HOBr, Br2, Br3-1) from polar and temperate diatoms. The highest rates were measured from Porosira glaciales (CCMP 651). Release rates are range from 0.84 to 180 fmoles bromine/hour/cell depending on the species or an approximate maximum of 950 nmoles bromine/mg chl a/hr (P. glaciales). The flux from the diatoms is 0.1 to 7.5 nmoles bromine/cm2 diatom surface/hr. This release occurs from an extracellular bromoperoxidase when a suitable organic substrate is absent. At 0.84 mM bromide (average seawater concentration), the optimal pH for Brox release is 6.5, which is the putative pH of the apoplastic space, and the optimal H2O2 concentration is 250 nM. Based on these results, it is estimated that the amount of bromine released from ice algae as Brox is 10 to 200 times greater than the release of bromine as bromoform from ice algae. The Brox so produced could participate in the abiotic formation of dihalogens in sea ice. Also, Brox released from diatoms may react with specific components of DOC, if present, to indirectly produce polybromomethanes both in sea ice and seawater. The amount of polyhalomethanes produced is not only dependent on the algal species present but also on the composition of DOC.

Measuring Wildfires From Aircraft And Satellites

NASA Technical Reports Server (NTRS)

Brass, J. A.; Arvesen, J. C.; Ambrosia, V. G.; Riggan, P. J.; Meyers, J. S.

1991-01-01

Aircraft and satellite systems yield wide-area views, providing total coverage of affected areas. System developed for use aboard aircraft includes digital scanner that records data in 12 channels. Transmits data to ground station for immediate use in fighting fires. Enables researchers to estimate gaseous and particulate emissions from fires. Provides information on temperatures of flame fronts and soils, intensities and rate of spread of fires, characteristics of fuels and smoke plumes, energy-release rates, and concentrations and movements of trace gases. Data relates to heating and cooling of soils, loss of nutrients, and effects on atmospheric, terrestrial, and aquatic systems.

Effects of solubilizing surfactants and loading of antiviral, antimicrobial, and antifungal drugs on their release rates from ethylene vinyl acetate copolymer

PubMed Central

Tallury, Padmavathy; Randall, Marcus K; Thaw, Khin L; Preisser, John S.; Kalachandra, Sid

2013-01-01

Objectives This study investigates the effects of surfactants and drug loading on the drug release rate from ethylene vinyl acetate (EVA) copolymer. The release rate of nystatin from EVA was studied with addition of non-ionic surfactants Tween 60 and Cremophor RH 40. In addition, the effect of increasing drug load on the release rates of nystatin, chlorhexidine diacetate and acyclovir is also presented. Method Polymer casting solutions were prepared by stirring EVA copolymer and nystatin (2.5 wt %) in dichloromethane. Nystatin and surfactants were added in ratios of (1:1), (1:2) and (1:3). Drug loading was studied with 2.5, 5.0, 7.5, and 10.0% wt. proportions of nystatin, chlorhexidine diacetate and acyclovir incorporated into a separate polymer. Three drug loaded polymer square films (3cm × 3cm × 0.08 cm) were cut from dry films to follow the kinetics of drug release at 37°C. 10 ml of either distilled water or PBS was used as the extracting medium that was replaced daily. PBS was used for nystatin release with addition of surfactants and water was used for the study on drug loading and surfactant release. The rate of drug release was measured by UV-spectrophotometer. The amount of surfactant released was determined by HPLC. Results The release of nystatin was low in PBS and its release rate increased with the addition of surfactants. Also, increasing surfactant concentrations resulted in increased drug release rates. The release rates of chlorhexidine diacetate (p<0.0001), acyclovir (p<0.0003) and nystatin (p<0.0017) linearly increased with increasing drug loads. The amount of surfactants released was above the CMC. Significance This study demonstrates that the three therapeutic agents show a sustained rate of drug release from EVA copolymer over extended periods of time. Nystatin release in PBS is low owing to its poor solubility. Its release rate is enhanced by addition of surfactants and increasing the drug load as well. PMID:17049593

Spall response of single-crystal copper

NASA Astrophysics Data System (ADS)

Turley, W. D.; Fensin, S. J.; Hixson, R. S.; Jones, D. R.; La Lone, B. M.; Stevens, G. D.; Thomas, S. A.; Veeser, L. R.

2018-02-01

We performed a series of systematic spall experiments on single-crystal copper in an effort to determine and isolate the effects of crystal orientation, peak stress, and unloading strain rate on the tensile spall strength. Strain rates ranging from 0.62 to 2.2 × 106 s-1 and peak shock stresses in the 5-14 GPa range, with one additional experiment near 50 GPa, were explored as part of this work. Gun-driven impactors, called flyer plates, generated flat top shocks followed by spall. This work highlights the effect of crystal anisotropy on the spall strength by showing that the spall strength decreases in the following order: [100], [110], and [111]. Over the range of stresses and strain rates explored, the spall strength of [100] copper depends strongly on both the strain rate and shock stress. Except at the very highest shock stress, the results for the [100] orientation show linear relationships between the spall strength and both the applied compressive stress and the strain rate. In addition, hydrodynamic computer code simulations of the spall experiments were performed to calculate the relationship between the strain rate near the spall plane in the target and the rate of free surface velocity release during the pullback. As expected, strain rates at the spall plane are much higher than the strain rates estimated from the free surface velocity release rate. We have begun soft recovery experiments and molecular dynamics calculations to understand the unusual recompression observed in the spall signature for [100] crystals.

Assessment of the abuse of tapentadol immediate release: the first 24 months.

PubMed

Dart, Richard C; Cicero, Theodore J; Surratt, Hilary L; Rosenblum, Andrew; Bartelson, Becki Bucher; Adams, Edgar H

2012-01-01

Prescription opioid analgesics play an important role in the management of moderate to severe pain. An unintended consequence of prescribing opioid analgesics is the abuse and diversion of these medications. The authors estimated abuse and diversion rates for tapentadol immediate release (IR) compared with oxycodone, hydrocodone, and tramadol during the first 24 months of tapentadol IR availability. The Researched Abuse, Diversion and Addiction-Related Surveillance (RADARS®) System measures rates of prescription opioid abuse and diversion throughout the United States. Quarterly data from the Poison Center, Drug Diversion, Opioid Treatment, and Survey of Key Informants' Patients (SKIP) programs were plotted to visually compare the rates of tapentadol IR abuse and diversion with those of other opioid analgesics from July 2009 through June 2011 using both cases per 100,000 population and per 1,000 unique recipients of dispensed drug (URDD) as denominators. Trends in abuse and diversion rates over time were determined using a linear regression model of rate versus time. During the 24 months following its introduction, tapentadol IR had very low population-based rates of abuse and diversion that were similar to rates for tramadol and lower than rates for oxycodone and hydrocodone. Rates of tapentadol IR abuse and diversion based on URDD were variable by program due to changes in market share and had not stabilized as of June 2011. Rates of tapentadol IR abuse and diversion have been low during the first 24 months after its launch. Continued monitoring of trends in these data is warranted.

Ion release from dental casting alloys as assessed by a continuous flow system: Nutritional and toxicological implications.

PubMed

López-Alías, José F; Martinez-Gomis, Jordi; Anglada, Josep M; Peraire, Maria

2006-09-01

The aims of this study were to quantify the metallic ions released by various dental alloys subjected to a continuous flow of saliva and to estimate the nutritional and toxicological implications of such a release. Four pieces of three nickel-based, one noble, one high-noble and two copper-aluminum alloys were cast and then immersed in a continuous flow of artificial saliva for 15 days. To simulate three meals a day, casts were subjected to thrice-daily episodes, lasting 30 min each and consisting of pH decreases and salinity increases. After 15 days, the metallic ions in the artificial saliva were analyzed. Data were expressed as averaged release rate: microg/cm2/day of ion released for each alloy. The highest value of 95% Cl of each ion was adapted to a hypothetical worst scenario of a subject with 100 cm2 of exposed metal surface. The results were compared with the tolerable upper daily intake level of each ion. The copper-aluminum alloys released copper, aluminum, nickel, manganese and iron. The nickel-based alloys essentially released nickel and chromium, while the beryllium-containing alloy released beryllium and significantly more nickel. The noble and high-noble alloys were very resistant to corrosion. The amount of ions released remained far below the upper tolerable intake level, with the exception of nickel, released by beryllium-containing nickel-based alloy, whose levels approach 50% of this threshold. The daily amount of ions released seems to be far below the tolerable upper intake levels for each ion.

Benefits from antidepressants: synthesis of 6-week patient-level outcomes from double-blind placebo-controlled randomized trials of fluoxetine and venlafaxine.

PubMed

Gibbons, Robert D; Hur, Kwan; Brown, C Hendricks; Davis, John M; Mann, J John

2012-06-01

Some meta-analyses suggest that efficacy of antidepressants for major depression is overstated and limited to severe depression. To determine the short-term efficacy of antidepressants for treating major depressive disorder in youth, adult, and geriatric populations. Reanalysis of all intent-to-treat person-level longitudinal data during the first 6 weeks of treatment of major depressive disorder from 12 adult, 4 geriatric, and 4 youth randomized controlled trials of fluoxetine hydrochloride and 21 adult trials of venlafaxine hydrochloride. All sponsor-conducted randomized controlled trials of fluoxetine and venlafaxine. Children's Depression Rating Scale-Revised scores (youth population), Hamilton Depression Rating Scale scores (adult and geriatric populations), and estimated response and remission rates at 6 weeks were analyzed for 2635 adults, 960 geriatric patients, and 708 youths receiving fluoxetine and for 2421 adults receiving immediate-release venlafaxine and 2461 adults receiving extended-release venlafaxine. Patients in all age and drug groups had significantly greater improvement relative to control patients receiving placebo. The differential rate of improvement was largest for adults receiving fluoxetine (34.6% greater than those receiving placebo). Youths had the largest treated vs control difference in response rates (24.1%) and remission rates (30.1%), with adult differences generally in the 15.6% (remission) to 21.4% (response) range. Geriatric patients had the smallest drug-placebo differences, an 18.5% greater rate of improvement, 9.9% for response and 6.5% for remission. Immediate-release venlafaxine produced larger effects than extended-release venlafaxine. Baseline severity could not be shown to affect symptom reduction. To our knowledge, this is the first research synthesis in this area to use complete longitudinal person-level data from a large set of published and unpublished studies. The results do not support previous findings that antidepressants show little benefit except for severe depression. The antidepressants fluoxetine and venlafaxine are efficacious for major depressive disorder in all age groups, although more so in youths and adults compared with geriatric patients. Baseline severity was not significantly related to degree of treatment advantage over placebo.

Measurement of IL-13–Induced iNOS-Derived Gas Phase Nitric Oxide in Human Bronchial Epithelial Cells

PubMed Central

Suresh, Vinod; Mih, Justin D.; George, Steven C.

2007-01-01

Exhaled nitric oxide (NO) is altered in numerous diseases including asthma, and is thought broadly to be a noninvasive marker of inflammation. However, the precise source of exhaled NO has yet to be identified, and the interpretation is further hampered by significant inter-subject variation. Using fully differentiated normal human bronchial epithelial (NHBE) cells, we sought to determine (1) the rate of NO release (flux, pl·s−1.cm−2) into the gas; (2) the effect of IL-13, a prominent mediator of allergic inflammation, on NO release; and (3) inter-subject/donor variability in NO release. NHBE cells from three different donors were cultured at an air–liquid interface and stimulated with different concentrations of IL-13 (0, 1, and 10 ng/ml) for 48 h. Gas phase NO concentrations in the headspace over the cells were measured using a chemiluminescence analyzer. The basal NO flux from the three donors (0.05 ± 0.03) is similar in magnitude to that estimated from exhaled NO concentrations, and was significantly increased by IL-13 in a donor-specific fashion. The increase in NO release was strongly correlated with inducible nitric oxide synthase (iNOS) gene and protein expression. There was a trend toward enhanced production of nitrate relative to nitrite as an end product of NO metabolism in IL-13–stimulated cells. NO release from airway epithelial cells can be directly measured. The rate of release in response to IL-13 is strongly dependent on the individual donor, but is primarily due to the expression of iNOS. PMID:17347445

Development of a level A in vitro-in vivo correlation for extended release dosage forms of quetiapine fumarate.

PubMed

Gonçalves de Lima, L; Rossi de Campos, D

2016-05-01

Quetiapine is an atypical antipsychotic recommended as first-line treatment for acute bipolar depression. The extended-release quetiapine formulation is intended to be administered as an once-daily dosing. The development of an in vitro-in vivo correlation (IVIVC) and the use of in vitro data to predict in vivo bioavailability parameters has been of great interest for the rational development and evaluation process for extended release dosage forms. The aim of this study was to develop an IVIVC for quetiapine extended release formulation. In vitro dissolution rate data were obtained using USP apparatus 2 at 50 rpm, in 3 bio-relevant dissolution media with different pH values (1.2, 4.5 and 6.8). The drug release profiles of the 2 extended release dosage forms were compared using the similarity factor (f 2). The relative bioavailability of quetiapine was evaluated by a single-dose, randomized-sequence, open-label, 2 period cross over study with 16 healthy volunteers. A linear level A IVIVC model was established using percentage of absorbed and dissolved data obtained at pH 1.2. The developed IVIVC model was employed to predict quetiapine concentration-time profiles, as well as the bioequivalence parameters for test formulation. Percent prediction errors were estimated for Cmax and AUC to evaluate the validity of the correlation. The values did not exceed 15%, proving the predictability of the correlation model. In conclusion, the established level A IVIVC model proved to be an excellent tool for predicting the rate and extent of quetiapine absorption as characterized by Cmax and AUC for test formulation. © Georg Thieme Verlag KG Stuttgart · New York.

In situ release rates of Cu and Zn from commercial antifouling paints at different salinities.

PubMed

Lagerström, Maria; Lindgren, J Fredrik; Holmqvist, Albin; Dahlström, Mia; Ytreberg, Erik

2018-02-01

Antifouling paints are environmentally risk assessed based on their biocidal release rates to the water phase. In situ release rates of copper (Cu) and zinc (Zn) were derived for five commercial paints in two recreational marinas with different salinities (5 and 14 PSU) using an X-Ray Fluorescence spectrometer (XRF). Salinity was found to significantly affect the Cu release, with twice the amount of Cu released at the higher salinity, while its influence on the Zn release was paint-specific. Site-specific release rates for water bodies with salinity gradients, e.g. the Baltic Sea, are therefore necessary for more realistic risk assessments of antifouling paints. Furthermore, the in situ release rates were up to 8 times higher than those generated using standardized laboratory or calculation methods. The environmental risk assessment repeated with the field release rates concludes that it is questionable whether the studied products should be allowed on the Swedish market. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Swelling, erosion and drug release characteristics of salbutamol sulfate from hydroxypropyl methylcellulose-based matrix tablets.

PubMed

Chaibva, Faith A; Khamanga, Sandile M M; Walker, Roderick B

2010-12-01

Hydrophilic matrix formulations are important and simple technologies that are used to manufacture sustained release dosage forms. Hydroxypropyl methylcellulose-based matrix tablets, with and without additives, were manufactured to investigate the rate of hydration, rate of erosion, and rate and mechanism of drug release. Scanning electron microscopy was used to assess changes in the microstructure of the tablets during drug release testing and whether these changes could be related to the rate of drug release from the formulations. The results revealed that the rate of hydration and erosion was dependent on the polymer combination(s) used, which in turn affected the rate and mechanism of drug release from these formulations. It was also apparent that changes in the microstructure of matrix tablets could be related to the different rates of drug release that were observed from the test formulations. The use of scanning electron microscopy provides useful information to further understand drug release mechanisms from matrix tablets.

Source term estimation of radioxenon released from the Fukushima Dai-ichi nuclear reactors using measured air concentrations and atmospheric transport modeling.

PubMed

Eslinger, P W; Biegalski, S R; Bowyer, T W; Cooper, M W; Haas, D A; Hayes, J C; Hoffman, I; Korpach, E; Yi, J; Miley, H S; Rishel, J P; Ungar, K; White, B; Woods, V T

2014-01-01

Systems designed to monitor airborne radionuclides released from underground nuclear explosions detected radioactive fallout across the northern hemisphere resulting from the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011. Sampling data from multiple International Modeling System locations are combined with atmospheric transport modeling to estimate the magnitude and time sequence of releases of (133)Xe. Modeled dilution factors at five different detection locations were combined with 57 atmospheric concentration measurements of (133)Xe taken from March 18 to March 23 to estimate the source term. This analysis suggests that 92% of the 1.24 × 10(19) Bq of (133)Xe present in the three operating reactors at the time of the earthquake was released to the atmosphere over a 3 d period. An uncertainty analysis bounds the release estimates to 54-129% of available (133)Xe inventory. Copyright © 2013 Elsevier Ltd. All rights reserved.

Potential Application of Silica Mineral from Dieng Mountain in Agriculture Sector to Control the Release Rate of Fertilizer Elements

NASA Astrophysics Data System (ADS)

Solihin; Mursito, Anggoro Tri; Dida, Eki N.; Erlangga, Bagus D.; Widodo

2017-07-01

Silica mineral, which comes along with geothermal fluid in Dieng, is a product of erosion, decomposition and dissolution of silicon oxide based mineral, which is followed by precipitation to form silica mineral. This silica cell structure is non crystalline, and it contains 85,60 % silicon oxide, 6.49 volatile elements, and also other oxide elements. Among the direct potential application of this silica is as raw material in slow release fertilizer. Silica in compacted slow release fertilizer is able control the release rate of fertilizer elements. Two type of slow release fertilizer has been made by using silica as the matrix in these slow release fertilizer. The first type is the mixing of ordinary solid fertilizer with Dieng silica, whereas the second one is the mixing of disposal leach water with Dieng silica. The release test shows that both of these modified fertilizers have slow release fertilizer characteristic. The release rate of fertilizer elements (magnesium, potassium, ammonium, and phosphate) can be significantly reduced. The addition of kaolin in the first type of slow release fertilizer makes the release rate of fertilizer elements can be more slowed down. Meanwhile in the second type of slow release fertilizer, the release rate is determined by ratio of silica/hydrogel. The lowest release rate is achieved by sample that has highest ratio of silica/hydrogel.

Environmental Releases for Calendar Year 2001

DOE Office of Scientific and Technical Information (OSTI.GOV)

DYEKMAN, D L

2002-08-01

This report fulfills the annual reporting requirements of US Department of Energy (DOE) Order 5400.1, General Environmental Protection Program. The report contains tabular data summaries on air emissions and liquid effluents released to the environment as well as nonroutine releases during calendar year (CY) 2001. These releases, bearing radioactive and hazardous substances, were from Bechtel Hanford, Inc. (BHI), CH2M HILL Hanford Group, Inc. (CHG), and Fluor Hanford (FH) managed facilities and activities. These data were obtained from direct sampling and analysis and from estimates based upon approved release factors. This report further serves as a supplemental resource to the Hanfordmore » Site Environmental Report (HSER PNNL-13910), published by the Pacific Northwest National Laboratory. HSER includes a yearly accounting of the impacts on the surrounding populace and environment from major activities at the Hanford Site. HSER also summarizes the regulatory compliance status of the Hanford Site. Tables ES-1 through ES-5 display comprehensive data summaries of CY2001 air emission and liquid effluent releases. The data displayed in these tables compiles the following: Radionuclide air emissions; Nonradioactive air emissions; Radionuclides in liquid effluents discharged to ground; Total volumes and flow rates of radioactive liquid effluents discharged to ground; and Radionuclides discharged to the Columbia River.« less

Rates of CO2 Mineralization in Geological Carbon Storage.

PubMed

Zhang, Shuo; DePaolo, Donald J

2017-09-19

Geologic carbon storage (GCS) involves capture and purification of CO 2 at industrial emission sources, compression into a supercritical state, and subsequent injection into geologic formations. This process reverses the flow of carbon to the atmosphere with the intention of returning the carbon to long-term geologic storage. Models suggest that most of the injected CO 2 will be "trapped" in the subsurface by physical means, but the most risk-free and permanent form of carbon storage is as carbonate minerals (Ca,Mg,Fe)CO 3 . The transformation of CO 2 to carbonate minerals requires supply of the necessary divalent cations by dissolution of silicate minerals. Available data suggest that rates of transformation are highly uncertain and difficult to predict by standard approaches. Here we show that the chemical kinetic observations and experimental results, when they can be reduced to a single cation-release time scale that describes the fractional rate at which cations are released to solution by mineral dissolution, show sufficiently systematic behavior as a function of pH, fluid flow rate, and time that the rates of mineralization can be estimated with reasonable certainty. The rate of mineralization depends on both the abundance (determined by the reservoir rock mineralogy) and the rate at which cations are released from silicate minerals by dissolution into pore fluid that has been acidified with dissolved CO 2 . Laboratory-measured rates and field observations give values spanning 8 to 10 orders of magnitude, but when they are evaluated in the context of a reservoir-scale reactive transport simulation, this range becomes much smaller. The reservoir scale simulations provide limits on the applicable conditions under which silicate mineral dissolution and subsequent carbonate mineral precipitation are likely to occur (pH 4.5 to 6, fluid flow velocity less than 5 m/year, and 50-100 years or more after the start of injection). These constraints lead to estimates of 200 to 2000 years for conversion of 60-90% of injected CO 2 when the reservoir rock has a sufficient volume fraction of divalent cation-bearing silicate minerals and confirms that when reservoir rock mineralogy is not favorable the fraction of CO 2 converted to carbonate minerals is minimal over 10 4 years. A sufficient amount of reactive minerals is typically about 20% by volume. Our approach may allow for rapid evaluation of mineralization potential of subsurface storage reservoirs and illustrates how reservoir scale modeling can be integrated with other observations to address key issues relating to engineering of geologic systems.

The Effects of Hypothermia on Fibrinogen Metabolism and Coagulation Function in Swine

DTIC Science & Technology

2007-01-01

blanket with circulating water at 48C. Fibrinogen synthesis and breakdown were quantified using a 6-hour stable isotope infusion with subsequent gas...tion and sufficient fibrinogen in the circulation . The effects of hypothermia on the coagulation process have been estimated 0026-0495/$ – see front...and released to circulation in 1 hour. Fibrinogen breakdown rate is the total loss of fibrinogen (expressed as milligram per kilogram of body weight

Release of engineered nanomaterials from personal care products throughout their life cycle

NASA Astrophysics Data System (ADS)

Keller, Arturo A.; Vosti, William; Wang, Hongtao; Lazareva, Anastasiya

2014-07-01

The impetus for this study was to provide release estimates that can serve to improve predictions of engineered nanomaterial (ENM) exposure for risk assessment. We determined the likely release of ENMs from personal care products (PCPs) through a consumer survey on use and disposal habits, and research on the types and quantities of ENMs in PCPs. Our estimates show that in the US zinc oxide (ZnO), with 1,800-2,100 mt yr-1, and titanium dioxide (TiO2), with 870-1,000 mt yr-1, represent 94 % of ENMs released into the environment or landfills from the use of PCPs. Around 36-43 % of ENMs from PCPs were estimated to end up in landfills, 24-36 % released to soils, 0.7-0.8 % to air, and 28-32 % to water bodies. ENMs in sunscreen represent around 81-82 % of total release, from ZnO and TiO2 as UV blockers, followed by facial moisturizer (7.5 %), foundation (5.7 %), and hair coloring products (3.1 %). Daily care products such as body wash, shampoo, and conditioner had by far the highest per capita and total use, but contributed little to the ENM release estimates as these products generally contain little or no ENMs. However, if ENMs are incorporated into these daily care products, this may substantially increase ENM release.

A TWO-WAY ROAD: RATES OF HIV INFECTION AND BEHAVIORAL RISK FACTORS AMONG DEPORTED MEXICAN LABOR MIGRANTS

PubMed Central

Rangel, M. Gudelia; Martinez-Donate, Ana P.; Hovell, Melbourne; Sipan, Carol L.; Zellner, Jennifer A.; Gonzalez-Fagoaga, Eduardo; Kelley, Norma J.; Asadi-Gonzalez, Ahmed; Amuedo-Dorantes, Catalina; Magis-Rodriguez, Carlos

2012-01-01

A large number of Mexican migrants are deported to Mexico and released in the North Mexican border region every year. Despite their volume and high vulnerability, little is known about the level of HIV infection and related risk behaviors among this hard-to-reach population. We conducted a cross-sectional, probability survey with deported Mexican migrants in Tijuana, Mexico (N=693) and estimated levels of HIV infection and behavioral risk factors among this migrant flow. The sample and population estimated rates of HIV for deported males were 1.23% and 0.80%, respectively. No positive cases were found among the female sample. We found high lifetime rates of reported sexually transmitted infections (22.3%) and last 12-months rates of unprotected sex (63.0%), sex with multiple sexual partners (18.1%), casual partners (25.7%), and sex workers (8.6%), compared to U.S. and Mexico adults. HIV prevention, testing, and treatment programs for this large, vulnerable, and transnational population need to be implemented in both the U.S. and Mexico. PMID:22562390

Are movies with tobacco, alcohol, drugs, sex, and violence rated for youth?: A comparison of rating systems in Argentina, Brazil, Mexico, and the United States

PubMed Central

Thrasher, James F.; Sargent, James D.; Vargas, Rosa; Braun, Sandra; Barrientos-Gutierrez, Tonatiuh; Sevigny, Eric L.; Billings, Deborah L.; Arillo-Santillán, Edna; Navarro, Ashley; Hardin, James

2014-01-01

Background This study aimed to determine between-country differences and changes over time in the portrayal of youth risk behaviors in films rated for youth in Argentina, Brazil, Mexico and the United States. Methods Content and ratings were analyzed for 362 films that were popular across all four countries from 2002–2009. Country-specific ratings were classified as either youth or adult, and Generalized Estimating Equations were used to determine between-country differences in the presence of tobacco, alcohol, drugs, sexual content, and violence in youth-rated films. Within-country differences in this content over time were also assessed, comparing films released from 2002–2005 with those released from 2006–2009. Results In the US, films rated for youth were less likely to contain all five risk behaviors than in youth-rated films in Argentina, Brazil, and, when the “15 and older” rating was considered a youth rating, in Mexico. All three Latin American countries “downrated” films that received an adult rating in the US. Nevertheless, tobacco and drug use in youth-rated films declined over time in all countries, whereas moderate to extreme alcohol use and violence involving children or youth increased in all countries. Conclusions Tobacco and drug use have declined in popular US films, but these behaviors are still prevalent in films rated for youth across the Americas. The apparent success of advocacy efforts to reduce tobacco and other drugs in films suggests that similar efforts be directed to reduce alcohol portrayals. PMID:24316001

Demon voltammetry and analysis software: Analysis of cocaine-induced alterations in dopamine signaling using multiple kinetic measures

PubMed Central

Yorgason, Jordan T.; España, Rodrigo A.; Jones, Sara R.

2011-01-01

The fast sampling rates of fast scan cyclic voltammetry make it a favorable method for measuring changes in brain monoamine release and uptake kinetics in slice, anesthetized, and freely moving preparations. The most common analysis technique for evaluating changes in dopamine signaling uses well-established Michaelis-Menten kinetic methods that can accurately model dopamine release and uptake parameters across multiple experimental conditions. Nevertheless, over the years, many researchers have turned to other measures to estimate changes in dopamine release and uptake, yet to our knowledge no systematic comparison amongst these measures has been conducted. To address this lack of uniformity in kinetic analyses, we have created the Demon Voltammetry and Analysis software suite, which is freely available to academic and non-profit institutions. Here we present an explanation of the Demon Acquisition and Analysis features, and demonstrate its utility for acquiring voltammetric data under in vitro, in vivo anesthetized, and freely moving conditions. Additionally, the software was used to compare the sensitivity of multiple kinetic measures of release and uptake to cocaine-induced changes in electrically evoked dopamine efflux in nucleus accumbens core slices. Specifically, we examined and compared tau, full width at half height, half-life, T20, T80, slope, peak height, calibrated peak dopamine concentration, and area under the curve to the well-characterized Michaelis-Menten parameters, dopamine per pulse, maximal uptake rate, and apparent affinity. Based on observed results we recommend tau for measuring dopamine uptake and calibrated peak dopamine concentration for measuring dopamine release. PMID:21392532

Kinetics of Brominated Flame Retardant (BFR) Releases from Granules of Waste Plastics.

PubMed

Sun, Bingbing; Hu, Yuanan; Cheng, Hefa; Tao, Shu

2016-12-20

Plastic components of e-waste contain high levels of brominated flame retardants (BFRs), whose releases cause environmental and human health concerns. This study characterized the release kinetics of polybrominated diphenyl ethers (PBDEs) from millimeter-sized granules processed from the plastic exteriors of two scrap computer displays at environmentally relevant temperatures. The release rate of a substitute of PBDEs, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), from the waste plastics, was reported for the first time. Deca-BDE was the most abundant PBDE congeners in both materials (87-89%), while BTBPE was also present at relatively high contents. The release kinetics of BFRs could be modeled as one-dimensional diffusion, while the temperature dependence of diffusion coefficients was well described by the Arrhenius equation. The diffusion coefficients of BFRs (at 30 °C) in the plastic matrices were estimated to be in the range of 10 -27.16 to 10 -19.96 m 2 ·s -1 , with apparent activation energies between 88.4 and 154.2 kJ·mol -1 . The half-lives of BFR releases (i.e., 50% depletion) from the plastic granules ranged from thousands to tens of billions of years at ambient temperatures. These findings suggest that BFRs are released very slowly from the matrices of waste plastics through molecular diffusion, while their emissions can be significantly enhanced with wear-and-tear and pulverization.

Mechanics of slip and fracture along small faults and simple strike-slip fault zones in granitic rock

NASA Astrophysics Data System (ADS)

Martel, Stephen J.; Pollard, David D.

1989-07-01

We exploit quasi-static fracture mechanics models for slip along pre-existing faults to account for the fracture structure observed along small exhumed faults and small segmented fault zones in the Mount Abbot quadrangle of California and to estimate stress drop and shear fracture energy from geological field measurements. Along small strike-slip faults, cracks that splay from the faults are common only near fault ends. In contrast, many cracks splay from the boundary faults at the edges of a simple fault zone. Except near segment ends, the cracks preferentially splay into a zone. We infer that shear displacement discontinuities (slip patches) along a small fault propagated to near the fault ends and caused fracturing there. Based on elastic stress analyses, we suggest that slip on one boundary fault triggered slip on the adjacent boundary fault, and that the subsequent interaction of the slip patches preferentially led to the generation of fractures that splayed into the zones away from segment ends and out of the zones near segment ends. We estimate the average stress drops for slip events along the fault zones as ˜1 MPa and the shear fracture energy release rate during slip as 5 × 102 - 2 × 104 J/m2. This estimate is similar to those obtained from shear fracture of laboratory samples, but orders of magnitude less than those for large fault zones. These results suggest that the shear fracture energy release rate increases as the structural complexity of fault zones increases.

Fission-gas release from uranium nitride at high fission rate density

NASA Technical Reports Server (NTRS)

Weinstein, M. B.; Kirchgessner, T. A.; Tambling, T. N.

1973-01-01

A sweep gas facility has been used to measure the release rates of radioactive fission gases from small UN specimens irradiated to 8-percent burnup at high fission-rate densities. The measured release rates have been correlated with an equation whose terms correspond to direct recoil release, fission-enhanced diffusion, and atomic diffusion (a function of temperature). Release rates were found to increase linearly with burnups between 1.5 and 8 percent. Pore migration was observed after operation at 1550 K to over 6 percent burnup.

Differential predation by northern squawfish Ptychocheilus oregonensis on live and dead juvenile salmonids in the Bonneville Dam tailrace (Columbia River)

USGS Publications Warehouse

Petersen, James H.; Gadomski, Dena M.; Poe, Thomas P.

1994-01-01

Juvenile salmonids (Oncorhynchus spp.) that have been killed or injured during dam passage may be highly vulnerable or preferred prey of predators that aggregate below dams. Salmonid loss due to predation will be overestimated using gut content analysis if some prey were dead or moribund when consumed. To examine this issue, field experiments were conducted in the Bonneville Dam tailrace (Columbia River) to compare rates of capture of live and dead juvenile salmonids by northern squawfish (Ptychocheilus oregonensis). Known numbers of coded-wire-tagged live and dead chinook salmon (O. tshawytscha) were released into the tailrace on six nights. Northern squawfish were collected after each release and their gut contents were examined for tags. When 50% of salmon released were dead, northern squawfish consumed 62% dead salmon. When 10% of salmon released were dead, comparable with dam passage mortality, 22% of the tags found in northern squawfish digestive tracts were from dead salmon. These results indicate that predator feeding behavior and prey condition are important considerations when estimating the impact of predation on a prey population.

Release of metal ions from fixed orthodontic appliance: an in vitro study in continuous flow system.

PubMed

Mikulewicz, Marcin; Chojnacka, Katarzyna; Wołowiec, Paulina

2014-01-01

To evaluate the release of metal ions from fixed orthodontic appliances. A new system for in vitro testing of dental materials was constructed and consisted of a thermostatic glass reactor that enabled immersion of the studied material. Experimental conditions reflected the human oral cavity, with a temperature of 37°C and a saliva flow rate of 0.5mL/min. The simulated fixed orthodontic appliance made of stainless steel was evaluated. Sampling was performed at several time points during the 28-day study, and the metal ion concentration was determined by inductively coupled plasma optical emission spectrometry. The total mass of released metal ions from the appliance during 4 weeks of the experiment was as follows nickel 18.7 μg, chromium 5.47 μg, copper 31.3 μg. The estimated doses of nickel, chromium, and copper determined by extrapolation of experimental data released during the treatment period were far below the toxic dose to humans. This shows that orthodontic treatment might not be a significant source of exposure to these metal ions.

Estimates of global, regional, and national annual CO{sub 2} emissions from fossil-fuel burning, hydraulic cement production, and gas flaring: 1950--1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boden, T.A.; Marland, G.; Andres, R.J.

1995-12-01

This document describes the compilation, content, and format of the most comprehensive C0{sub 2}-emissions database currently available. The database includes global, regional, and national annual estimates of C0{sub 2} emissions resulting from fossil-fuel burning, cement manufacturing, and gas flaring in oil fields for 1950--92 as well as the energy production, consumption, and trade data used for these estimates. The methods of Marland and Rotty (1983) are used to calculate these emission estimates. For the first time, the methods and data used to calculate CO, emissions from gas flaring are presented. This C0{sub 2}-emissions database is useful for carbon-cycle research, providesmore » estimates of the rate at which fossil-fuel combustion has released C0{sub 2} to the atmosphere, and offers baseline estimates for those countries compiling 1990 C0{sub 2}-emissions inventories.« less

Linking behavior, physiology, and survival of Atlantic Salmon smolts during estuary migration

USGS Publications Warehouse

Stich, Daniel S.; Zydlewski, Gayle B.; Kocik, John F.; Zydlewski, Joseph D.

2015-01-01

Decreased marine survival is identified as a component driver of continued declines of Atlantic Salmon Salmo salar. However, estimates of marine mortality often incorporate loss incurred during estuary migration that may be mechanistically distinct from factors affecting marine mortality. We examined movements and survival of 941 smolts (141 wild and 800 hatchery-reared fish) released in freshwater during passage through the Penobscot River estuary, Maine, from 2005 to 2013. We related trends in estuary arrival date, movement rate, and survival to fish characteristics, migratory history, and environmental conditions in the estuary. Fish that experienced the warmest thermal history arrived in the estuary 8 d earlier than those experiencing the coolest thermal history during development. Estuary arrival date was 10 d later for fish experiencing high flow than for fish experiencing low flow. Fish released furthest upstream arrived in the estuary 3 d later than those stocked further downstream but moved 0.5 km/h faster through the estuary. Temporally, movement rate and survival in the estuary both peaked in mid-May. Spatially, movement rate and survival both decreased from freshwater to the ocean. Wild smolts arrived in the estuary later than hatchery fish, but we observed no change in movement rate or survival attributable to rearing history. Fish with the highest gill Na+, K+-ATPase activity incurred 25% lower mortality through the estuary than fish with the lowest gill Na+, K+-ATPase activity. Smolt survival decreased (by up to 40%) with the increasing number of dams passed (ranging from two to nine) during freshwater migration. These results underscore the importance of physiological preparedness on performance and the delayed, indirect effects of dams on survival of Atlantic Salmon smolts during estuary migration, ultimately affecting marine survival estimates.

Groundbased investigation of comet 67p/churyumov- gerasimenko, target of the spacecraft Mission Rosetta

NASA Astrophysics Data System (ADS)

de Almeida, A. A.; Trevisan Sanzovo, D.; Sanzovo, G. C.; Boczko, R.; Miguel Torres, R.

In this work, we make a comparative study of Comet 67P/Churyumov-Gerasimenko, target of Mission Rosetta, with Comets 1P/Halley and Hyakutake(C/1996 B2). Water and gas) release rates are derived from visual magnitudes (mv), determined mostly by amateur astronomers, and listed in several issues of International Comet Quarterly(ICQ). We make a systematic and uniform analysis of continuum fluxes obtained at visual wavelengths and, using the framework of photometric theory of Newburn & Spinrad (1985, 1989), we estimate dust release rates, qd (in g/s), effective particle sizes, a (in micron), and dust-to-gas mass ratios, for this important sample of comets. We also determine the color excess of the dust particles, CE, relative to the Sun at wavelength ranges 477.0-524.0 nm in the 1996 return of Comet 67P/Churyumov-Gerasimenko, and 365.0-484.5 nm for Comets 1P/Halley and C/1996 B2.

A smoothed stochastic earthquake rate model considering seismicity and fault moment release for Europe

NASA Astrophysics Data System (ADS)

Hiemer, S.; Woessner, J.; Basili, R.; Danciu, L.; Giardini, D.; Wiemer, S.

2014-08-01

We present a time-independent gridded earthquake rate forecast for the European region including Turkey. The spatial component of our model is based on kernel density estimation techniques, which we applied to both past earthquake locations and fault moment release on mapped crustal faults and subduction zone interfaces with assigned slip rates. Our forecast relies on the assumption that the locations of past seismicity is a good guide to future seismicity, and that future large-magnitude events occur more likely in the vicinity of known faults. We show that the optimal weighted sum of the corresponding two spatial densities depends on the magnitude range considered. The kernel bandwidths and density weighting function are optimized using retrospective likelihood-based forecast experiments. We computed earthquake activity rates (a- and b-value) of the truncated Gutenberg-Richter distribution separately for crustal and subduction seismicity based on a maximum likelihood approach that considers the spatial and temporal completeness history of the catalogue. The final annual rate of our forecast is purely driven by the maximum likelihood fit of activity rates to the catalogue data, whereas its spatial component incorporates contributions from both earthquake and fault moment-rate densities. Our model constitutes one branch of the earthquake source model logic tree of the 2013 European seismic hazard model released by the EU-FP7 project `Seismic HAzard haRmonization in Europe' (SHARE) and contributes to the assessment of epistemic uncertainties in earthquake activity rates. We performed retrospective and pseudo-prospective likelihood consistency tests to underline the reliability of our model and SHARE's area source model (ASM) using the testing algorithms applied in the collaboratory for the study of earthquake predictability (CSEP). We comparatively tested our model's forecasting skill against the ASM and find a statistically significant better performance for testing periods of 10-20 yr. The testing results suggest that our model is a viable candidate model to serve for long-term forecasting on timescales of years to decades for the European region.

Do fungi need to be included within environmental radiation protection assessment models?

PubMed

Guillén, J; Baeza, A; Beresford, N A; Wood, M D

2017-09-01

Fungi are used as biomonitors of forest ecosystems, having comparatively high uptakes of anthropogenic and naturally occurring radionuclides. However, whilst they are known to accumulate radionuclides they are not typically considered in radiological assessment tools for environmental (non-human biota) assessment. In this paper the total dose rate to fungi is estimated using the ERICA Tool, assuming different fruiting body geometries, a single ellipsoid and more complex geometries considering the different components of the fruit body and their differing radionuclide contents based upon measurement data. Anthropogenic and naturally occurring radionuclide concentrations from the Mediterranean ecosystem (Spain) were used in this assessment. The total estimated weighted dose rate was in the range 0.31-3.4 μGy/h (5 th -95 th percentile), similar to natural exposure rates reported for other wild groups. The total estimated dose was dominated by internal exposure, especially from 226 Ra and 210 Po. Differences in dose rate between complex geometries and a simple ellipsoid model were negligible. Therefore, the simple ellipsoid model is recommended to assess dose rates to fungal fruiting bodies. Fungal mycelium was also modelled assuming a long filament. Using these geometries, assessments for fungal fruiting bodies and mycelium under different scenarios (post-accident, planned release and existing exposure) were conducted, each being based on available monitoring data. The estimated total dose rate in each case was below the ERICA screening benchmark dose, except for the example post-accident existing exposure scenario (the Chernobyl Exclusion Zone) for which a dose rate in excess of 35 μGy/h was estimated for the fruiting body. Estimated mycelium dose rate in this post-accident existing exposure scenario was close to the 400 μGy/h benchmark for plants, although fungi are generally considered to be less radiosensitive than plants. Further research on appropriate mycelium geometries and their radionuclide content is required. Based on the assessments presented in this paper, there is no need to recommend that fungi should be added to the existing assessment tools and frameworks; if required some tools allow a geometry representing fungi to be created and used within a dose assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Monitoring of Juvenile Yearling Chinook Salmon and Steelhead Survival and Passage at Bonneville Dam, Spring 2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ploskey, Gene R.; Faber, Derrek M.; Weiland, Mark A.

2011-02-01

The purpose of this study was to estimate the survival for yearling Chinook salmon and steelhead smolts during spring 2010 in a portion of the Columbia River that includes Bonneville Dam. The study estimated smolt survival from a virtual release at Bonneville Dam to a survival array 81 km downstream of Bonneville Dam. We also estimated median forebay residence time, median tailrace egress time, and spill passage efficiency (SPE), as required in the Columbia Basin Fish Accords. A single release design was used to estimate survival from Bonneville Dam to a primary array located 81 km downstream of Bonneville. Themore » approach did not include a reference tailrace release. Releases of acoustic-tagged smolts above John Day Dam to Hood River contributed to the formation of virtual releases at a Bonneville Dam forebay entrance array and at the face of the dam. A total of 3,880 yearling Chinook salmon and 3,885 steelhead smolts were tagged and released in the investigation. The Juvenile Salmon Acoustic Telemetry System (JSATS) tag model number ATS-156dB, weighing 0.438 g in air, was used in this investigation.« less

Monitoring and Evaluation of Yearling Fall Chinook Salmon (Oncorhynchus tshawytscha) Released from Acclimation Facilities Upstream of Lower Granite Dam; 2003 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rocklage, Stephen J.

The Nez Perce Tribe, in cooperation with the U.S. Fish and Wildlife Service and Washington Department of Fish and Wildlife, conducted monitoring and evaluation studies on Lyons Ferry Hatchery reared yearling fall Chinook salmon Oncorhynchus tshawytscha that were acclimated and released at three Fall Chinook Acclimation Project (FCAP) sites upstream of Lower Granite Dam in 2003. This was the eighth year of a long-term project to supplement natural spawning populations of Snake River stock fall Chinook salmon upstream of Lower Granite Dam. The 437,633 yearlings released from the Fall Chinook Acclimation Project facilities were short of the 450,000 fish quota.more » We use Passive Integrated Transponder (PIT) tag technology to monitor the primary performance measures of survival to mainstem dams and migration timing. We also monitor size, condition and tag/mark retention at release. We released 7,492 PIT tagged yearlings from Pittsburg Landing, 7,494 from Big Canyon and 2,497 from Captain John Rapids. Fish health sampling indicated that, overall, bacterial kidney disease levels at the acclimation facilities could be considered medium with 37-83% of the fish sampled rating medium to very high. Mean fork lengths (95% confidence interval) of the PIT tagged groups ranged from 153.7 mm (153.2-154.2 mm) at Captain John Rapids to 164.2 mm (163.9-164.5 mm) at Pittsburg Landing. Mean condition factors ranged from 1.06 at Lyons Ferry Hatchery to 1.22 at Captain John Rapids. Estimated survival (95% confidence interval) of PIT tagged yearlings from release to Lower Granite Dam ranged from 83.1% (80.7-85.5%) for Big Canyon to 91.7% (87.7-95.7%) for Captain John Rapids. Estimated survival from release to McNary Dam ranged from 59.9% (54.6-65.2%) for Big Canyon to 69.4% (60.5-78.4%) for Captain John Rapids. Median migration rates to Lower Granite Dam, based on all observations of PIT tagged yearlings from the FCAP facilities, ranged from 5.8 river kilometers per day (rkm/d) for Captain John Rapids to 16.2 rkm/d for Pittsburg Landing. Median migration rates to McNary Dam ranged from 11.7 rkm/d for Captain John Rapids to 17.6 rkm/d for Pittsburg Landing. Median travel times from the FCAP facilities were about 8-15 days to Lower Granite Dam and 22-27 days to McNary Dam. Median arrival dates at Lower Granite Dam, based on all observations of PIT tagged yearling groups from the FCAP facilities, ranged from April 23-25. Median arrival dates at McNary Dam for Pittsburg Landing, Big Canyon and Captain John Rapids groups ranged from May 4-10.« less

Estimating Biases for Regional Methane Fluxes using Co-emitted Tracers

NASA Astrophysics Data System (ADS)

Bambha, R.; Safta, C.; Michelsen, H. A.; Cui, X.; Jeong, S.; Fischer, M. L.

2017-12-01

Methane is a powerful greenhouse gas, and the development and improvement of emissions models rely on understanding the flux of methane released from anthropogenic sources relative to releases from other sources. Increasing production of shale oil and gas in the mid-latitudes and associated fugitive emissions are suspected to be a dominant contributor to the global methane increase. Landfills, sewage treatment, and other sources may be dominant sources in some parts of the U.S. Large discrepancies between emissions models present a great challenge to reconciling atmospheric measurements with inventory-based estimates for various emissions sectors. Current approaches for measuring regional emissions yield highly uncertain estimates because of the sparsity of measurement sites and the presence of multiple simultaneous sources. Satellites can provide wide spatial coverage at the expense of much lower measurement precision compared to ground-based instruments. Methods for effective assimilation of data from a variety of sources are critically needed to perform regional GHG attribution with existing measurements and to determine how to structure future measurement systems including satellites. We present a hierarchical Bayesian framework to estimate surface methane fluxes based on atmospheric concentration measurements and a Lagrangian transport model (Weather Research and Forecasting and Stochastic Time-Inverted Lagrangian Transport). Structural errors in the transport model are estimated with the help of co-emitted traces species with well defined decay rates. We conduct the analyses at regional scales that are based on similar geographical and meteorological conditions. For regions where data are informative, we further refine flux estimates by emissions sector and infer spatially and temporally varying biases parameterized as spectral random field representations.

Does Prison Crowding Predict Higher Rates of Substance Use Related Parole Violations? A Recurrent Events Multi-Level Survival Analysis.

PubMed

Ruderman, Michael A; Wilson, Deirdra F; Reid, Savanna

2015-01-01

This administrative data-linkage cohort study examines the association between prison crowding and the rate of post-release parole violations in a random sample of prisoners released with parole conditions in California, for an observation period of two years (January 2003 through December 2004). Crowding overextends prison resources needed to adequately protect inmates and provide drug rehabilitation services. Violence and lack of access to treatment are known risk factors for drug use and substance use disorders. These and other psychosocial effects of crowding may lead to higher rates of recidivism in California parolees. Rates of parole violation for parolees exposed to high and medium levels of prison crowding were compared to parolees with low prison crowding exposure. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using a Cox model for recurrent events. Our dataset included 13070 parolees in California, combining individual level parolee data with aggregate level crowding data for multilevel analysis. Comparing parolees exposed to high crowding with those exposed to low crowding, the effect sizes from greatest to least were absconding violations (HR 3.56 95% CI: 3.05-4.17), drug violations (HR 2.44 95% CI: 2.00-2.98), non-violent violations (HR 2.14 95% CI: 1.73-2.64), violent and serious violations (HR 1.88 95% CI: 1.45-2.43), and technical violations (HR 1.86 95% CI: 1.37-2.53). Prison crowding predicted higher rates of parole violations after release from prison. The effect was magnitude-dependent and particularly strong for drug charges. Further research into whether adverse prison experiences, such as crowding, are associated with recidivism and drug use in particular may be warranted.

Does Prison Crowding Predict Higher Rates of Substance Use Related Parole Violations? A Recurrent Events Multi-Level Survival Analysis

PubMed Central

Ruderman, Michael A.; Wilson, Deirdra F.; Reid, Savanna

2015-01-01

Objective This administrative data-linkage cohort study examines the association between prison crowding and the rate of post-release parole violations in a random sample of prisoners released with parole conditions in California, for an observation period of two years (January 2003 through December 2004). Background Crowding overextends prison resources needed to adequately protect inmates and provide drug rehabilitation services. Violence and lack of access to treatment are known risk factors for drug use and substance use disorders. These and other psychosocial effects of crowding may lead to higher rates of recidivism in California parolees. Methods Rates of parole violation for parolees exposed to high and medium levels of prison crowding were compared to parolees with low prison crowding exposure. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using a Cox model for recurrent events. Our dataset included 13070 parolees in California, combining individual level parolee data with aggregate level crowding data for multilevel analysis. Results Comparing parolees exposed to high crowding with those exposed to low crowding, the effect sizes from greatest to least were absconding violations (HR 3.56 95% CI: 3.05–4.17), drug violations (HR 2.44 95% CI: 2.00–2.98), non-violent violations (HR 2.14 95% CI: 1.73–2.64), violent and serious violations (HR 1.88 95% CI: 1.45–2.43), and technical violations (HR 1.86 95% CI: 1.37–2.53). Conclusions Prison crowding predicted higher rates of parole violations after release from prison. The effect was magnitude-dependent and particularly strong for drug charges. Further research into whether adverse prison experiences, such as crowding, are associated with recidivism and drug use in particular may be warranted. PMID:26492490

Physicochemical Characteristics and Slow Release Performances of Chlorpyrifos Encapsulated by Poly(butyl acrylate-co-styrene) with the Cross-Linker Ethylene Glycol Dimethacrylate.

PubMed

Wang, Yu; Gao, Zideng; Shen, Feng; Li, Yang; Zhang, Sainan; Ren, Xueqin; Hu, Shuwen

2015-06-03

Chlorpyrifos' application and delivery to the target substrate needs to be controlled to improve its use. Herein, poly(butyl acrylate-co-styrene) (poly(BA/St)) and poly(BA/St/ethylene glycol dimethacrylate (EGDMA)) microcapsules loaded with chlorpyrifos as a slow release formulation were prepared by emulsion polymerization. The effects of structural characteristics on the chlorpyrifos microcapsule particle size, entrapment rate (ER), pesticide loading (PL), and release behaviors in ethyl alcohol were investigated. Fourier transform infrared and thermogravimetric analysis confirmed the successful entrapment of chlorpyrifos. The ER and PL varied with the BA/St monomer ratio, chlorpyrifos/monomer core-to-shell ratio, and EGDMA cross-linker content with consequence that suitable PL was estimated to be smaller than 3.09% and the highest ER was observed as 96.74%. The microcapsule particle size (88.36-101.8 nm) remained mostly constant. The extent of sustainable release decreased with increasing content of BA, St, or chlorpyrifos in the oil phase. Specifically, an adequate degree of cross-linking with EGMDA (0.5-2.5%) increased the extent of sustainable release considerably. However, higher levels of cross-linking with EGDMA (5-10%) reduced the extent of sustainable release. Chlorpyrifos release from specific microcapsules (monomer ratio 1:2 with 0.5% EGDMA or 5 g chlopyrifos) tended to be a diffusion-controlled process, while for others, the kinetics probably indicated the initial rupture release.

Phaethon Near Earth

NASA Astrophysics Data System (ADS)

Jewitt, David

2017-08-01

Planet-crossing asteroid (3200) Phaethon, source of the Geminid meteoroid stream, will pass close to Earth in December 2017. Observations with HST are proposed to image debris ejected from this object at 1 AU heliocentric distance, to estimate the ejection velocities as the Earth passes through the orbit plane, and to estimate the dust production rate for comparison with the rates needed to sustain the Geminid stream in steady-state. These measurements will help determine the mechanism behind the ejection of the Geminids, a long-standing puzzle. While the release of micron-sized particles (probably by thermal fracture) has been recorded at Phaethon's perihelion (0.14 AU), mass loss has never been detected otherwise, raising the puzzle of the ejection mechanism and duration. The close approach (0.07 AU) on December 17 gives a once-in-a-lifetime opportunity to observe Phaethon at high sensitivity with a resolution of a few kilometers.

Accidental Turbulent Discharge Rate Estimation from Videos

NASA Astrophysics Data System (ADS)

Ibarra, Eric; Shaffer, Franklin; Savaş, Ömer

2015-11-01

A technique to estimate the volumetric discharge rate in accidental oil releases using high speed video streams is described. The essence of the method is similar to PIV processing, however the cross correlation is carried out on the visible features of the efflux, which are usually turbulent, opaque and immiscible. The key step in the process is to perform a pixelwise time filtering on the video stream, in which the parameters are commensurate with the scales of the large eddies. The velocity field extracted from the shell of visible features is then used to construct an approximate velocity profile within the discharge. The technique has been tested on laboratory experiments using both water and oil jets at Re ~105 . The technique is accurate to 20%, which is sufficient for initial responders to deploy adequate resources for containment. The software package requires minimal user input and is intended for deployment on an ROV in the field. Supported by DOI via NETL.

Metal release from stainless steel particles in vitro-influence of particle size.

PubMed

Midander, K; Pan, J; Wallinder, I Odnevall; Leygraf, C

2007-01-01

Human inhalation of airborne metallic particles is important for health risk assessment. To study interactions between metallic particles and the human body, metal release measurements of stainless steel powder particles were performed in two synthetic biological media simulating lung-like environments. Particle size and media strongly influence the metal release process. The release rate of Fe is enhanced compared with Cr and Ni. In artificial lysosomal fluid (ALF, pH 4.5), the accumulated amounts of released metal per particle loading increase drastically with decreasing particle size. The release rate of Fe per unit surface area increases with decreasing particle size. Compared with massive sheet metal, fine powder particles (<4 microm) show similar release rates of Cr and Ni, but a higher release rate of Fe. Release rates in Gamble's solution (pH 7.4), for all powders investigated, are significantly lower compared to ALF. No clear trend is seen related to particle size in Gamble's solution.

Effect of enhanced nitrogen input on release of nutrients and nutrient availability in stands of tall fern Athyrium distentifolium

NASA Astrophysics Data System (ADS)

Tå¯Ma, Ivan; Holuib, Petr; Záhora, Jaroslav; Fiala, Karel

2010-05-01

Improved light conditions, after destruction of tree canopy, soil acidification and increased nitrogen availability, support intensive spreading of acidophilous perennial grasses and stands of tall fern (Athyrium distentifolium) on deforested sites in the Moravian-Silesian Beskydy Mts. (the Czech Republic). The aim of the study was to determine how higher inputs of nitrogen affect the release of nutrients during decomposition processes of fern litter. The experimental site was chosen on a southwest-facing slope of the Kněhyně Mt. (49o31´ N, 18o 32´E, 1170 m a.s.l.) in the Moravian-Silesin Beskydy Mts. in the Czech Republic. The area is characterized by an annual mean air temperature of 5.6 oC and annual precipitation of 1110 mm. A large fern stand was divided in four blocks (5x3 m) and on two of them higher doses of nitrogen were applied (50 kgN/ha in five doses in the course of the growing season). Similarly, mesh-bags with fresh natural litter of fern were used to determine rate of litter decomposition during one year. Samples were inserted in both nitrogen treated and untreated fern stands in autumn 2006 and 2007 collected in autumn 2007 and 2008. On the basis of litter amount estimated at the start and at the end of exposure and of actual content of minerals in original and exposed litter, the release and/or accumulation of minerals during decomposition were calculated. The availability (more or less in the case of ammonia-nitrogen) and movement of percolated nitrogen (mainly in the case of nitrate-nitrogen) was estimated in situ by the trapping of mineral N into the ion exchange resin (IER) inserted into special cover. The decomposition rate of native A. distentifolium litter was approximately the same (29-30 %) at both nitrogen availability, however the element release from decomposed litter was higher for N, P and Ca in both years and for K and Mg in the first year as well. However, decomposition rate of cellulose was two times greater in fern stands than in adjacent spruce stands without ferns. The values are expressed as the captured mineral nitrogen into ion exchange resins exposed in situ. The availability of soil ammonia- as well as nitrate- nitrogen in control stockings, and after the addition of different sources (raw silk and cellulose) were, in general, not very different below fern plants and in the bare soils. It can be concluded, that the microbial competition for available nitrogen is very high after the addition of cellulose, which consequently restrict the rate of mineral nitrogen trapped into the ion exchange resin. In contrary higher amounts of captured mineral nitrogen were estimated after the addition of raw silk. This study was supported by GP AS CR (IAA 600050616) and the Research plan No. MSM6215648905, Ministry of Education, CR.

Impact-based earthquake alerts with the U.S. Geological Survey's PAGER system: what's next?

USGS Publications Warehouse

Wald, D.J.; Jaiswal, K.S.; Marano, K.D.; Garcia, D.; So, E.; Hearne, M.

2012-01-01

In September 2010, the USGS began publicly releasing earthquake alerts for significant earthquakes around the globe based on estimates of potential casualties and economic losses with its Prompt Assessment of Global Earthquakes for Response (PAGER) system. These estimates significantly enhanced the utility of the USGS PAGER system which had been, since 2006, providing estimated population exposures to specific shaking intensities. Quantifying earthquake impacts and communicating estimated losses (and their uncertainties) to the public, the media, humanitarian, and response communities required a new protocol—necessitating the development of an Earthquake Impact Scale—described herein and now deployed with the PAGER system. After two years of PAGER-based impact alerting, we now review operations, hazard calculations, loss models, alerting protocols, and our success rate for recent (2010-2011) events. This review prompts analyses of the strengths, limitations, opportunities, and pressures, allowing clearer definition of future research and development priorities for the PAGER system.

Monitoring and Evaluation of Smolt Migration in the Columbia Basin : Volume XVIII: Survival and Transportation Effects of Migrating Snake River Wild Chinook Salmon and Steelhead: Historical Estimates From 1996-2004 and Comparison to Hatchery Results. Draft.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buchanan, Rebecca A.; Skalski, John R.; Broms, Kristin

The combined juvenile and adult detection histories of PIT-tagged wild salmonids migrating through the Federal Columbia River Power System (FCRPS) were analyzed using the ROSTER (River-Ocean Survival and Transportation Effects Routine) statistical release-recapture model. This model, implemented by software Program ROSTER, was used to estimate survival on large temporal and spatial scales for PIT-tagged wild spring and summer Chinook salmon and steelhead released in the Snake River Basin upstream of Lower Granite Dam from 1996 to 2004. In addition, annual results from wild salmonids were compared with results from hatchery salmonids, which were presented in a previous report in thismore » series (Buchanan, R. A., Skalski, J. R., Lady, J. L., Westhagen, P., Griswold, J., and Smith, S. 2007, 'Survival and Transportation Effects for Migrating Snake River Hatchery Chinook Salmon and Steelhead: Historical Estimates from 1996-2003', Technical report, Bonneville Power Administration, Project 1991-051-00). These results are reported here. Annual estimates of the smolt-to-adult return ratio (SAR), juvenile inriver survival from Lower Granite to Bonneville, the ocean return probability from Bonneville to Bonneville, and adult upriver survival from Bonneville to Lower Granite are reported. Annual estimates of transport-inriver (T/I) ratios and differential post-Bonneville mortality (D) are reported on a dam-specific basis for release years with sufficient numbers of wild PIT-tagged smolts transported. Transportation effects are estimated only for dams where at least 1,000 tagged wild smolts were transported from a given upstream release group. Because few wild Chinook salmon and steelhead tagged upstream of Lower Granite Dam were transported before the 2003 release year, T/I and D were estimated only for the 2003 and 2004 release years. Performance measures include age-1-ocean adult returns for steelhead, but not for Chinook salmon. Spring and summer Chinook salmon release groups were pooled across the entire Snake River Basin upstream of Lower Granite Dam for this report. Annual estimates of SAR from Lower Granite back to Lower Granite averaged 0.92% with an estimated standard error (dSE) of 0.25% for wild spring and summer Chinook salmon for tagged groups released from 1996 through 2004, omitting age-1-ocean (jack) returns. Only for the 1999 and 2000 release years did the wild Chinook SAR approach the target value of 2%, identified by the NPCC as the minimum SAR necessary for recovery. Annual estimates of SAR for wild steelhead from the Snake River Basin averaged 0.63% (dSE = 0.15%), including age-1-ocean returns, for release years 1996 through 2004. For release years when the ocean return probability from Bonneville back to Bonneville could be estimated (i.e., 1999 through 2004), it was estimated that on average approximately 83% of the total integrated mortality for nontransported, tagged wild spring and summer Chinook, and 78% for steelhead (omitting the 2001 release year), occurred during the ocean life stage (i.e., from Bonneville to Bonneville). This suggests that additional monitoring and research efforts should include the ocean and estuary environment. Annual estimates of the dam-specific T/I for Lower Granite Dam were available for the 2003 and 2004 release years for both wild Chinook salmon and wild steelhead. The estimated T/I for Lower Granite was significantly > 1.0 for Chinook in 2004 (P < 0.0001) and for steelhead in both 2003 (P < 0.0001) and 2004 (P < 0.0001), indicating that for these release years, wild fish transported at Lower Granite returned there in higher proportions than fish that were returned to the river at Lower Granite, or that passed Lower Granite without detection as juveniles. Annual estimates of the dam-specific T/I for Little Goose Dam were available for wild Chinook salmon for both 2003 and 2004. The estimated T/I for Little Goose was significantly > 1.0 for wild Chinook in 2004 (P = 0.0024), but not in 2003 (P = 0.1554). Differential post-Bonneville mortality (D) is the ratio of post-Bonneville survival to Lower Granite Dam of transported fish to that of nontransported ('inriver') fish. Estimates of D were available for transportation from Lower Granite and Little Goose dams in 2003 and 2004 for wild Chinook, and from Lower Granite Dam in 2003 and 2004 for wild steelhead. Point estimates ranged from 0.74 (dSE = 0.29) for transportation of wild Chinook salmon from Lower Granite Dam in 2003 to 1.91 (dSE = 0.61) for transportation of wild steelhead from Lower Granite Dam in 2003. Small transport groups resulted in high uncertainty on the point estimates, and only for 2003 steelhead transported from Lower Granite Dam did transported fish have significantly greater post-Bonneville survival than nontransported fish (P = 0.0213).« less

Qualitative Release Assessment to Estimate the Likelihood of Henipavirus Entering the United Kingdom

PubMed Central

Snary, Emma L.; Ramnial, Vick; Breed, Andrew C.; Stephenson, Ben; Field, Hume E.; Fooks, Anthony R.

2012-01-01

The genus Henipavirus includes Hendra virus (HeV) and Nipah virus (NiV), for which fruit bats (particularly those of the genus Pteropus) are considered to be the wildlife reservoir. The recognition of henipaviruses occurring across a wider geographic and host range suggests the possibility of the virus entering the United Kingdom (UK). To estimate the likelihood of henipaviruses entering the UK, a qualitative release assessment was undertaken. To facilitate the release assessment, the world was divided into four zones according to location of outbreaks of henipaviruses, isolation of henipaviruses, proximity to other countries where incidents of henipaviruses have occurred and the distribution of Pteropus spp. fruit bats. From this release assessment, the key findings are that the importation of fruit from Zone 1 and 2 and bat bushmeat from Zone 1 each have a Low annual probability of release of henipaviruses into the UK. Similarly, the importation of bat meat from Zone 2, horses and companion animals from Zone 1 and people travelling from Zone 1 and entering the UK was estimated to pose a Very Low probability of release. The annual probability of release for all other release routes was assessed to be Negligible. It is recommended that the release assessment be periodically re-assessed to reflect changes in knowledge and circumstances over time. PMID:22328916

Spline-Based Parameter Estimation Techniques for Two-Dimensional Convection and Diffusion Equations.

DTIC Science & Technology

1986-07-01

brassicae ) were related at a point adjacent to and downwind from a cabbage ( brassica ) crop (9]. Although Wright [161 had rejected anemotaxis as a...tunnel experiments by Coaker and Smith [71 indicated that female E. brassicae do fly upwind in the presence of brassica odor. To resolve this issue Hawkes...sought to calculate dispersal rates of E. Brassicae released from a point exposed to brassica odor. When recapture data suggested random dispersal

Poverty and Education Report: Students Are Not to Blame--Understanding the Structural Causes of Family Poverty. BCTF Research Report. Section XII. 2009-EI-01

ERIC Educational Resources Information Center

White, Margaret

2009-01-01

In 2006, there were an estimated 181,000 low-income children in the province, with British Columbia (BC) reporting the highest before-tax child poverty rate (21.9%) in Canada (15.8%) for the fifth year in a row. This was the news in the "2008 Child Poverty Report Card" recently released by the First Call: BC Child and Youth Advocacy…

Estimating release of carbon from 1990 and 1991 forest fires in Alaska

NASA Technical Reports Server (NTRS)

Kaisischke, Eric S.; French, Nancy H. F.; Bourgeau-Chavez, Laura L.; Christensen, N. L., Jr.

1995-01-01

An improved method to estimate the amounts of carbon released during fires in the boreal forest zone of Alaska in 1990 and 1991 is described. This method divides the state into 64 distinct physiographic regions and estimates areal extent of five different land covers: two forest types, peat land, tundra, and nonvegetated. The areal extent of each cover type was estimated from a review of topographic maps of each region and observations on the distribution of foreat types within the state. Using previous observations and theoretical models for the two forest types found in interior Alaska, models of biomass accumulation as a function of stand age were developed. Stand age distributions for each region were determined using a statistical distribution based on fire frequency, which was from available long-term historical records. Estimates of the degree of biomass combusted were based on recent field observations as well as research reported in the literature. The location and areal extent of fires in this region for 1990 and 1991 were based on both field observations and analysis of satellite (advanced very high resolution radiometer (AVHRR)) data sets. Estimates of average carbon release for the two study years ranged between 2.54 and 3.00 kg/sq m, which are 2.2 to 2.6 times greater than estimates used in other studies of carbon release through biomass burning in boreal forests. Total average annual carbon release for the two years ranged between 0.012 and 0.018 Pg C/yr, with the lower value resulting from the AVHRR estimates of fire location and area.

Estimation of effectiveness of three methods of feral cat population control by use of a simulation model.

PubMed

McCarthy, Robert J; Levine, Stephen H; Reed, J Michael

2013-08-15

To predict effectiveness of 3 interventional methods of population control for feral cat colonies. Population model. Estimates of vital data for feral cats. Data were gathered from the literature regarding the demography and mating behavior of feral cats. An individual-based stochastic simulation model was developed to evaluate the effectiveness of trap-neuter-release (TNR), lethal control, and trap-vasectomy-hysterectomy-release (TVHR) in decreasing the size of feral cat populations. TVHR outperformed both TNR and lethal control at all annual capture probabilities between 10% and 90%. Unless > 57% of cats were captured and neutered annually by TNR or removed by lethal control, there was minimal effect on population size. In contrast, with an annual capture rate of ≥ 35%, TVHR caused population size to decrease. An annual capture rate of 57% eliminated the modeled population in 4,000 days by use of TVHR, whereas > 82% was required for both TNR and lethal control. When the effect of fraction of adult cats neutered on kitten and young juvenile survival rate was included in the analysis, TNR performed progressively worse and could be counterproductive, such that population size increased, compared with no intervention at all. TVHR should be preferred over TNR for management of feral cats if decrease in population size is the goal. This model allowed for many factors related to the trapping program and cats to be varied and should be useful for determining the financial and person-effort commitments required to have a desired effect on a given feral cat population.

Local survival of Dunlin wintering in California

USGS Publications Warehouse

Warnock, N.; Page, G.W.; Sandercock, B.K.

1997-01-01

We estimated local annual survival of 1,051 individually color-banded Dunlin (Calidris alpina) at Bolinas Lagoon, California from 1979 to 1992. Resighting rates for birds banded as adults varied significantly among years, and resighting rates for first-year birds varied by sex and year. No significant differences in local survival rates were found between males and females in any age classes. First-year birds had lower local survival rates than adults. We suspect that raptor predation accounted for much of this difference and other variation in survival rates. Adult Dunlin had lower local survival rates in the year of capture than in subsequent years. Variation in resighting of some groups of individuals including transient Dunlin may account for some differences. However, capture and release of Dunlin may induce short-term behavioral changes that increase the risk of depredation by avian predators within the first few days after capture.

Development of an osmotic pump system for controlled delivery of diclofenac sodium.

PubMed

Emara, L H; Taha, N F; Badr, R M; Mursi, N M

2012-10-01

Based on an elementary osmotic pump, controlled release systems of diclofenac sodium (DS) were designed to deliver the drug in a zero-order release pattern. Osmotic pump tablets containing 100 mg DS were prepared and coated with either semipermeable (SPM) or microporous (PM) membranes. The tablet coats were composed of hydrophobic triacetin (TA) or hydrophilic polyethylene glycol 400 (PEG 400) incorporated in cellulose acetate (CA) solution, for SPM and PM, respectively. Variable tablet core compositions such as swelling polymers (PEO and HPMC) and osmotic agents (lactose, NaCl, and KCl) were studied. An optimized, sensitive and well controlled in vitro release design, based on the flow-through cell (FTC), was utilized to discriminate between preparations. The results revealed that the presence of PEG 400 in the coating membrane accelerated the drug release rate, while TA suppressed the release rate of DS. In the case of SPM, the amount of DS released was inversely proportional to the membrane thickness, where 5% (w/w) weight gain gave a higher DS release rate than 10% (w/w). Results of different tablet core compositions revealed that the release rate of DS decreased as PEO molecular weight increased. HPMC K15M showed the lowest DS release rate. The presence of lactose, KCl, or NaCl pronouncedly affected DS release rate depending on polymer type in the core. Scanning electron microscopy (SEM) confirmed formation of pores in the membrane that accounts for faster DS release rate. These results revealed that DS could be formulated as an osmotic pump system with a prolonged, zero-order release pattern.

Metal release rate from AISI 316L stainless steel and pure Fe, Cr and Ni into a synthetic biological medium--a comparison.

PubMed

Herting, G; Wallinder, I Odnevall; Leygraf, C

2008-09-01

Metal release rates from stainless steel grade 316L were investigated in artificial lysosomal fluid (ALF), simulating a human inflammatory cell response. The main focus was placed on release rates of main alloying elements using graphite furnace atomic absorption spectroscopy, and changes in surface oxide composition by means of X-ray photoelectron spectroscopy. To emphasise that alloys and pure metals possess totally different intrinsic properties, comparative studies were performed on the pure alloying constituents: iron, nickel and chromium. Significant differences in release rates were observed due to the presence of a passive surface film on stainless steel. Iron and nickel were released at rates more than 300 times lower from the 316L alloy compared with the pure metals whereas the release rate of chromium was similar. Iron was preferentially released compared with nickel and chromium. Immersion in ALF resulted in the gradual enrichment of chromium in the surface film, a small increase of nickel, and the reduction of oxidized iron with decreasing release rates of alloy constituents as a result. As expected, released metals from stainless steel grade 316L were neither in proportion to the bulk alloy composition nor to the surface film composition.

Kerogen maturation data in the Uinta Basin, Utah, USA, constrain predictions of natural hydrocarbon seepage into the atmosphere

NASA Astrophysics Data System (ADS)

Mansfield, Marc L.

2014-03-01

Natural seepage of methane from the lithosphere to the atmosphere occurs in regions with large natural gas deposits. According to some authors, it accounts for roughly 5% of the global methane budget. I explore a new approach to estimate methane fluxes based on the maturation of kerogen, which is the hydrocarbon polymer present in petroleum source rocks and whose decomposition leads to the formation of oil and natural gas. The temporal change in the atomic H/C ratio of kerogen lets us estimate the total carbon mass released by it in the form of oil and natural gas. Then the time interval of active kerogen decomposition lets us estimate the average annual formation rate of oil and natural gas in any given petroleum system, which I demonstrate here using the Uinta Basin of eastern Utah as an example. Obviously, this is an upper bound to the average annual rate at which natural gas seeps into the atmosphere. After adjusting for biooxidation of natural gas, I conclude that the average annual seepage rate in the Uinta Basin is not greater than (3100 ± 900) tonne yr-1. This is (0.5 ± 0.15)% of the total flux of methane into the atmosphere over the Basin, as measured during aircraft flights. I speculate about the difference between the regional 0.5% and the global 5% estimates.

Nitrogen release from rock and soil under simulated field conditions

USGS Publications Warehouse

Holloway, J.M.; Dahlgren, R.A.; Casey, W.H.

2001-01-01

A laboratory study was performed to simulate field weathering and nitrogen release from bedrock in a setting where geologic nitrogen has been suspected to be a large local source of nitrate. Two rock types containing nitrogen, slate (1370 mg N kg-1) and greenstone (480 mg N kg-1), were used along with saprolite and BC horizon sand from soils derived from these rock types. The fresh rock and weathered material were used in batch reactors that were leached every 30 days over 6 months to simulate a single wet season. Nitrogen was released from rock and soil materials at rates between 10-20 and 10-19 mo1 N cm-2 s-1. Results from the laboratory dissolution experiments were compared to in situ soil solutions and available mineral nitrogen pools from the BC horizon of both soils. Concentrations of mineral nitrogen (NO3- + NH4+) in soil solutions reached the highest levels at the beginning of the rainy season and progressively decreased with increased leaching. This seasonal pattern was repeated for the available mineral nitrogen pool that was extracted using a KCl solution. Estimates based on these laboratory release rates bracket stream water NO3-N fluxes and changes in the available mineral nitrogen pool over the active leaching period. These results confirm that geologic nitrogen, when present, may be a large and reactive pool that may contribute as a non-point source of nitrate contamination to surface and ground waters. ?? 2001 Elsevier Science B.V. All rights reserved.

Statistical inference for template aging

NASA Astrophysics Data System (ADS)

Schuckers, Michael E.

2006-04-01

A change in classification error rates for a biometric device is often referred to as template aging. Here we offer two methods for determining whether the effect of time is statistically significant. The first of these is the use of a generalized linear model to determine if these error rates change linearly over time. This approach generalizes previous work assessing the impact of covariates using generalized linear models. The second approach uses of likelihood ratio tests methodology. The focus here is on statistical methods for estimation not the underlying cause of the change in error rates over time. These methodologies are applied to data from the National Institutes of Standards and Technology Biometric Score Set Release 1. The results of these applications are discussed.

Burrows of the semi-terrestrial crab Ucides cordatus enhance CO2 release in a North Brazilian mangrove forest.

PubMed

Pülmanns, Nathalie; Diele, Karen; Mehlig, Ulf; Nordhaus, Inga

2014-01-01

Ucides cordatus is an abundant mangrove crab in Brazil constructing burrows of up to 2 m depth. Sediment around burrows may oxidize during low tides. This increase in sediment-air contact area may enhance carbon degradation processes. We hypothesized that 1) the sediment CO2 efflux rate is greater with burrows than without and 2) the reduction potential in radial profiles in the sediment surrounding the burrows decreases gradually, until approximating non-bioturbated conditions. Sampling was conducted during the North Brazilian wet season at neap tides. CO2 efflux rates of inhabited burrows and plain sediment were measured with a CO2/H2O gas analyzer connected to a respiration chamber. Sediment redox potential, pH and temperature were measured in the sediment surrounding the burrows at horizontal distances of 2, 5, 8 and 15 cm at four sediment depths (1, 10, 30 and 50 cm) and rH values were calculated. Sediment cores (50 cm length) were taken to measure the same parameters for plain sediment. CO2 efflux rates of plain sediment and individual crab burrows with entrance diameters of 7 cm were 0.7-1.3 µmol m(-2) s(-1) and 0.2-0.4 µmol burrows(-1) s(-1), respectively. CO2 released from a Rhizophora mangle dominated forest with an average of 1.7 U. cordatus burrows(-1) m(-2) yielded 1.0-1.7 µmol m(-2) s(-1), depending on the month and burrow entrance diameter. Laboratory experiments revealed that 20-60% of the CO2 released by burrows originated from crab respiration. Temporal changes in the reduction potential in the sediment surrounding the burrows did not influence the CO2 release from burrows. More oxidized conditions of plain sediment over time may explain the increase in CO2 release until the end of the wet season. CO2 released by U. cordatus and their burrows may be a significant pathway of CO2 export from mangrove sediments and should be considered in mangrove carbon budget estimates.

Burrows of the Semi-Terrestrial Crab Ucides cordatus Enhance CO2 Release in a North Brazilian Mangrove Forest

PubMed Central

Pülmanns, Nathalie; Diele, Karen; Mehlig, Ulf; Nordhaus, Inga

2014-01-01

Ucides cordatus is an abundant mangrove crab in Brazil constructing burrows of up to 2 m depth. Sediment around burrows may oxidize during low tides. This increase in sediment-air contact area may enhance carbon degradation processes. We hypothesized that 1) the sediment CO2 efflux rate is greater with burrows than without and 2) the reduction potential in radial profiles in the sediment surrounding the burrows decreases gradually, until approximating non-bioturbated conditions. Sampling was conducted during the North Brazilian wet season at neap tides. CO2 efflux rates of inhabited burrows and plain sediment were measured with a CO2/H2O gas analyzer connected to a respiration chamber. Sediment redox potential, pH and temperature were measured in the sediment surrounding the burrows at horizontal distances of 2, 5, 8 and 15 cm at four sediment depths (1, 10, 30 and 50 cm) and rH values were calculated. Sediment cores (50 cm length) were taken to measure the same parameters for plain sediment. CO2 efflux rates of plain sediment and individual crab burrows with entrance diameters of 7 cm were 0.7–1.3 µmol m−2 s−1 and 0.2–0.4 µmol burrows−1 s−1, respectively. CO2 released from a Rhizophora mangle dominated forest with an average of 1.7 U. cordatus burrows−1 m−2 yielded 1.0–1.7 µmol m−2 s−1, depending on the month and burrow entrance diameter. Laboratory experiments revealed that 20–60% of the CO2 released by burrows originated from crab respiration. Temporal changes in the reduction potential in the sediment surrounding the burrows did not influence the CO2 release from burrows. More oxidized conditions of plain sediment over time may explain the increase in CO2 release until the end of the wet season. CO2 released by U. cordatus and their burrows may be a significant pathway of CO2 export from mangrove sediments and should be considered in mangrove carbon budget estimates. PMID:25313661

Nanostructured lipid carriers: effect of solid phase fraction and distribution on the release of encapsulated materials.

PubMed

Dan, Nily

2014-11-25

Emulsions, solid lipid nanoparticles (SLN), and nanostructured lipid carriers (NLC) containing a mix of liquid and solid domains are of interest as encapsulation vehicles for hydrophobic compounds. Studies of the release rate from these particles yield contradictory results: Some find that increasing the fraction of solid phase increases the rate of release and others the opposite. In this paper we study the release of encapsulated materials from lipid-based nanoparticles using Monte Carlo simulations. We find that, quite surprisingly, the release rate is largely insensitive to the size of solid domains or the fraction of solid phase. However, the distribution of the domains significantly affects the rate of release: Solid domains located at the interface with the surrounding solution inhibit transport, while nanoparticles where the solid domains are concentrated in the center enhance it. The latter can lead to release rates in NLCs that are faster than in the equivalent emulsions. We conclude that controlling the release rate from NLCs requires the ability to determine the location and distribution of the solid phase, which may be achieved through choice of the surfactants stabilizing the particles, incorporation of nucleation sites, and/or the cooling rates and temperatures.

The mid-Cretaceous super plume, carbon dioxide, and global warming

NASA Technical Reports Server (NTRS)

Caldeira, Ken; Rampino, Michael R.

1991-01-01

Carbon-dioxide releases associated with a mid-Cretaceous super plume and the emplacement of the Ontong-Java Plateau have been suggested as a principal cause of the mid-Cretaceous global warming. A carbonate-silicate cycle model is developed to quantify the possible climatic effects of these CO2 releases, utilizing four different formulations for the rate of silicate-rock weathering as a function of atmospheric CO2. CO2 emissions resulting from super-plume tectonics could have produced atmospheric CO2 levels from 3.7 to 14.7 times the modern preindustrial value of 285 ppm. Based on the temperature sensitivity to CO2 increases used in the weathering-rate formulations, this would cause a global warming of from 2.8 to 7.7 C over today's glogal mean temperature. Altered continental positions and higher sea level may have been contributed about 4.8 C to mid-Cretaceous warming. Thus, the combined effects of paleogeographic changes and super-plume related CO2 emissions could be in the range of 7.6 to 12.5 C, within the 6 to 14 C range previously estimated for mid-Cretaceous warming. CO2 releases from oceanic plateaus alone are unlikely to have been directly responsible for more than 20 percent of the mid-Cretaceous increase in atmospheric CO2.

Monitoring and Evaluation of Yearling Fall Chinook Salmon (Oncorhynchus tshawytscha) Released from Acclimation Facilities Upstream of Lower Granite Dam; 1999 Annual Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rocklage, Stephen J.; Kellar, Dale S.

2005-07-01

The Nez Perce Tribe, in cooperation with the U.S. Fish and Wildlife Service and Washington Department of Fish and Wildlife, conducted monitoring and evaluation studies on Lyons Ferry Hatchery reared yearling fall Chinook salmon Oncorhynchus tshawytscha that were acclimated and released at three Fall Chinook Acclimation Project (FCAP) sites upstream of Lower Granite Dam along with yearlings released on-station from Lyons Ferry Hatchery in 1999. This was the fourth year of a long-term project to supplement natural spawning populations of Snake River stock fall Chinook salmon upstream of Lower Granite Dam. The 453,117 yearlings released from the Fall Chinook Acclimationmore » Project facilities not only slightly exceeded the 450,000 fish quota, but a second release of 76,386 yearlings (hereafter called Surplus) were acclimated at the Big Canyon facility and released about two weeks after the primary releases. We use Passive Integrated Transponder (PIT) tag technology to monitor the primary performance measures of survival to mainstem dams and migration timing. We also monitor size, condition and tag/mark retention at release. We released 9,941 PIT tagged yearlings from Pittsburg Landing, 9,583 from Big Canyon, 2,511 Big Canyon Surplus and 2,494 from Captain John Rapids. The Washington Department of Fish and Wildlife released 983 PIT tagged yearlings from Lyons Ferry Hatchery. Fish health sampling indicated that, overall, bacterial kidney disease levels could be considered relatively low and did not appear to increase after transport to the acclimation facilities. Compared to prior years, Quantitative Health Assessment Indices were relatively low at Pittsburg Landing and Lyons Ferry Hatchery and relatively high at Big Canyon and Captain John Rapids. Mean fork lengths (95% confidence interval) of the release groups ranged from 147.4 mm (146.7-148.1 mm) at Captain John Rapids to 163.7 mm (163.3-164.1 mm) at Pittsburg Landing. Mean condition factors ranged from 1.04 at Pittsburg Landing to 1.23 at Captain John Rapids. Estimated survival (95% confidence interval) of PIT tagged yearlings from release to Lower Granite Dam ranged from 87.8% (82.1-93.4%) for Big Canyon Surplus to 94.1% (90.1-98.1%) for Captain John Rapids. Estimated survival from release to McNary Dam ranged from 58.7% (49.3-68.1%) for Big Canyon Surplus to 71.3% (60.1-82.5%) for Captain John Rapids. Median migration rates to Lower Granite Dam, based on all observations of PIT tagged yearlings from the FCAP facilities, ranged from 9.3 river kilometers per day (rkm/d) for Captain John Rapids to 18.7 rkm/d for Pittsburg Landing. Median migration rates to McNary Dam ranged from 9.0 rkm/d for Lyons Ferry Hatchery to 17.3 rkm/d for Pittsburg Landing. Median travel times from the FCAP facilities were about 7-10 days to Lower Granite Dam and 21-23 days to McNary Dam. Median arrival dates at Lower Granite Dam, based on all observations of PIT tagged yearling groups from the FCAP facilities, were all from April 23-25. The median arrival date for Big Canyon Surplus was May 4. Median arrival dates at McNary Dam for Pittsburg Landing, Big Canyon and Captain John Rapids groups were all from May 7-8. Median arrival dates at McNary Dam were May 17 for Big Canyon Surplus and April 26 for Lyons Ferry Hatchery.« less

Energy budget and propagation of faults via shearing and opening using work optimization

NASA Astrophysics Data System (ADS)

Madden, Elizabeth H.; Cooke, Michele L.; McBeck, Jessica

2017-08-01

We present numerical models of faults propagating by work optimization in a homogeneous medium. These simulations allow quantification and comparison of the energy budgets of fault growth by shear versus tensile failure. The energy consumed by growth of a fault, Wgrow, propagating by in-line shearing is 76% of the total energy associated with that growth, while 24% is spent on frictional work during propagation. Wgrow for a fault propagating into intact rock by tensile failure, at an angle to the parent fault, consumes 60% of the work budget, while only 6% is consumed by frictional work associated with propagation. Following the conservation of energy, this leaves 34% of the energy budget available for other activities and suggests that out-of-plane propagation of faults in Earth's crust may release energy for other processes, such as permanent damage zone formation or rupture acceleration. Comparison of these estimates of Wgrow with estimates of the critical energy release rate and earthquake fracture energy at several scales underscores their theoretical similarities and their dependence on stress drop.

Topical cyclone rainfall characteristics as determined from a satellite passive microwave radiometer

NASA Technical Reports Server (NTRS)

Rodgers, E. B.; Adler, R. F.

1979-01-01

Data from the Nimbus-5 Electrically Scanning Microwave Radiometer (ESMR-5) were used to calculate latent heat release and other rainfall parameters for over 70 satellite observations of 21 tropical cyclones in the tropical North Pacific Ocean. The results indicate that the ESMR-5 measurements can be useful in determining the rainfall characteristics of these storms and appear to be potentially useful in monitoring as well as predicting their intensity. The ESMR-5 derived total tropical cyclone rainfall estimates agree favorably with previous estimates for both the disturbance and typhoon stages. The mean typhoon rainfall rate (1.9 mm h(-1)) is approximately twice that of disturbances (1.1 mm h(-1)).

Natural gas fugitive emissions rates constrained by global atmospheric methane and ethane.

PubMed

Schwietzke, Stefan; Griffin, W Michael; Matthews, H Scott; Bruhwiler, Lori M P

2014-07-15

The amount of methane emissions released by the natural gas (NG) industry is a critical and uncertain value for various industry and policy decisions, such as for determining the climate implications of using NG over coal. Previous studies have estimated fugitive emissions rates (FER)--the fraction of produced NG (mainly methane and ethane) escaped to the atmosphere--between 1 and 9%. Most of these studies rely on few and outdated measurements, and some may represent only temporal/regional NG industry snapshots. This study estimates NG industry representative FER using global atmospheric methane and ethane measurements over three decades, and literature ranges of (i) tracer gas atmospheric lifetimes, (ii) non-NG source estimates, and (iii) fossil fuel fugitive gas hydrocarbon compositions. The modeling suggests an upper bound global average FER of 5% during 2006-2011, and a most likely FER of 2-4% since 2000, trending downward. These results do not account for highly uncertain natural hydrocarbon seepage, which could lower the FER. Further emissions reductions by the NG industry may be needed to ensure climate benefits over coal during the next few decades.

Economic assessment of wild bird mortality induced by the use of lead gunshot in European wetlands.

PubMed

Andreotti, Alessandro; Guberti, Vittorio; Nardelli, Riccardo; Pirrello, Simone; Serra, Lorenzo; Volponi, Stefano; Green, Rhys E

2018-01-01

In European wetlands, at least 40 bird species are exposed to the risk of lead poisoning caused by ingestion of spent lead gunshot. Adopting a methodology developed in North America, we estimated that about 700,000 individuals of 16 waterbird species die annually in the European Union (EU) (6.1% of the wintering population) and one million in whole Europe (7.0%) due to acute effects of lead poisoning. Furthermore, threefold more birds suffer sub-lethal effects. We assessed the economic loss due to this lead-induced mortality of these 16 species by calculating the costs of replacing lethally poisoned wild birds by releasing captive-bred ones. We assessed the cost of buying captive-bred waterbirds for release from market surveys and calculated how many captive-bred birds would have to be released to compensate for the loss, taking into account the high mortality rate of captive birds (72.7%) in the months following release into the wild. Following this approach, the annual cost of waterbird mortality induced by lead shot ingestion is estimated at 105 million euros per year in the EU countries and 142 million euros in the whole of Europe. An alternative method, based upon lost opportunities for hunting caused by deaths due to lead poisoning, gave similar results of 129 million euros per year in the EU countries and 185 million euros per year in the whole of Europe. For several reasons these figures should be regarded as conservative. Inclusion of deaths of species for which there were insufficient data and delayed deaths caused indirectly by lead poisoning and effects on reproduction would probably increase the estimated losses substantially. Nevertheless, our results suggest that the benefits of a restriction on the use of lead gunshot over wetlands could exceed the cost of adapting to non-lead ammunition. Copyright © 2017 Elsevier B.V. All rights reserved.

Dispersal of Male Aedes aegypti in a Coastal Village in Southern Mexico

PubMed Central

Valerio, Laura; Facchinelli, Luca; Ramsey, Janine M.; Scott, Thomas W.

2012-01-01

Most Aedes aegypti dispersal studies have focused on females because of their central role in dengue virus transmission. Only a few mark-release-recapture (MRR) studies provided insights into male Ae. aegypti dispersal. To fill this knowledge gap, we conducted five male Ae. aegypti MRR experiments in a coastal village in southern Mexico. Small and large male cohorts were marked with fluorescent dusts, released outside buildings, and recaptures were carried out by using backpack aspirators. Recapture rates ranged between 0.35% and 6.55% and median distance traveled was 12–166 meters. A statistically significant difference in median distance traveled with large males dispersing farther than small ones was detected only in one experiment (MRR5: U = 3.5, P < 0.01). Male dispersal data will be useful for constructing and estimating parameter values and validating models that will be used to plan the most effective release strategies for genetically modified male Ae. aegypti. PMID:22492152

QUANTIFICATION OF FUGITIVE REACTIVE ALKENE EMISSIONS FROM PETROCHEMICAL PLANTS WITH PERFLUOROCARBON TRACERS.

DOE Office of Scientific and Technical Information (OSTI.GOV)

SENUM,G.I.; DIETZ,R.N.

2004-06-30

Recent studies demonstrate the impact of fugitive emissions of reactive alkenes on the atmospheric chemistry of the Houston Texas metropolitan area (1). Petrochemical plants located in and around the Houston area emit atmospheric alkenes, such as ethene, propene and 1,3-butadiene. The magnitude of emissions is a major uncertainty in assessing their effects. Even though the petrochemical industry reports that fugitive emissions of alkenes have been reduced to less than 0.1% of daily production, recent measurement data, obtained during the TexAQS 2000 experiment indicates that emissions are perhaps a factor of ten larger than estimated values. Industry figures for fugitive emissionsmore » are based on adding up estimated emission factors for every component in the plant to give a total estimated emission from the entire facility. The dramatic difference between estimated and measured rates indicates either that calculating emission fluxes by summing estimates for individual components is seriously flawed, possibly due to individual components leaking well beyond their estimated tolerances, that not all sources of emissions for a facility are being considered in emissions estimates, or that there are known sources of emissions that are not being reported. This experiment was designed to confirm estimates of reactive alkene emissions derived from analysis of the TexAQS 2000 data by releasing perfluorocarbon tracers (PFTs) at a known flux from a petrochemical plant and sampling both the perfluorocarbon tracer and reactive alkenes downwind using the Piper-Aztec research aircraft operated by Baylor University. PFTs have been extensively used to determine leaks in pipelines, air infiltration in buildings, and to characterize the transport and dispersion of air parcels in the atmosphere. Over 20 years of development by the Tracer Technology Center (TTC) has produced a range of analysis instruments, field samplers and PFT release equipment that have been successfully deployed in a large variety of experiments. PFTs are inert, nontoxic, noncombustible and nonreactive. Up to seven unique PFTs can be simultaneously released, sampled and analyzed and the technology is well suited for determining emission fluxes from large petrochemical facilities. The PFT experiment described here was designed to quantitate alkene emissions from a single petrochemical facility, but such experiments could be applied to other industrial sources or groups of sources in the Houston area.« less

Annual survival and recruitment in a Ruby-throated Hummingbird population, excluding the effect of transient individuals

USGS Publications Warehouse

Hilton, B.; Miller, M.W.

2003-01-01

We estimated annual apparent survival, recruitment, and rate of population growth of breeding Ruby-throated Hummingbirds (Archilochus colubris), while controlling for transients, by using 18 years of capture-mark-recapture data collected during 1984-2001 at Hilton Pond Center for Piedmont Natural History near York, South Carolina. Resident males had lower apparent survival (0.30 +/- 0.05 SE) than females (0.43 +/- 0.04). Estimates of apparent survival did not differ by age. Point estimates suggested that newly banded males were less likely than females to be residents, but standard errors of these estimates overlapped (males: 0.60 +/- 0.14 SE; females: 0.67 +/- 0.09). Estimated female recruitment was 0.60 +/- 0.06 SE, meaning that 60% of adult females present in any given year had entered the population during the previous year. Our estimate for rate of change indicated the population of female hummingbirds was stable during the study period (1.04 +/- 0.04 SE). We suggest an annual goal of greater than or equal to 64 adult females and greater than or equal to 64 immature females released per banding area to enable rigorous future tests for effects of covariates on population dynamics. Development of a broader cooperating network of hummingbird banders in eastern North America could allow tests for regional or metapopulation dynamics in this species.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jablonská, Jana, E-mail: jana.jablonska@vsb.cz; Kozubková, Milada, E-mail: milada.kozubkova@vsb.cz

Cavitation today is a very important problem that is solved by means of experimental and mathematical methods. The article deals with the generation of cavitation in convergent divergent nozzle of rectangular cross section. Measurement of pressure, flow rate, temperature, amount of dissolved air in the liquid and visualization of cavitation area using high-speed camera was performed for different flow rates. The measurement results were generalized by dimensionless analysis, which allows easy detection of cavitation in the nozzle. For numerical simulation the multiphase mathematical model of cavitation consisting of water and vapor was created. During verification the disagreement with the measurementsmore » for higher flow rates was proved, therefore the model was extended to multiphase mathematical model (water, vapor and air), due to release of dissolved air. For the mathematical modeling the multiphase turbulence RNG k-ε model for low Reynolds number flow with vapor and air cavitation was used. Subsequently the sizes of the cavitation area were verified. In article the inlet pressure and loss coefficient depending on the amount of air added to the mathematical model are evaluated. On the basis of the approach it may be create a methodology to estimate the amount of released air added at the inlet to the modeled area.« less

The effect of rearing methods on survival of reintroduced black-footed ferrets

USGS Publications Warehouse

Biggins, D.E.; Godbey, J.L.; Hanebury, L.R.; Luce, B.; Marinari, P.E.; Matchett, M.R.; Vargas, A.

1998-01-01

We estimated minimum survival rates for 282 young-of-year, captive-reared, black-footed ferrets (Mustela nigripes) reintroduced into prairie dog (Cynomys spp.) colonies in Wyoming, Montana, and South Dakota. We used night surveys with spotlights to locate ferrets about 1 month and 9 months postrelease. We modeled minimum survival rates using gender, year, site, and 4 rearing methods. Minimum survival rates were highest (30% for 1 month, 20% for 9 months) for ferrets reared from early ages in outdoor pens with simulated prairie dog habitat; survival was lowest for cage-reared ferrets released without pen experience (11% for 1 month, 2% for 9 months). Rearing method and year influenced 1-month survival in a comparison of 3 levels of pen experience (pen rearing as defined above, transfer of kits from zoos to pen facilities at age 60-90 days, transfer at age >90 days) during releases in 1994-95 in Montana. Higher survival was associated with intensive management of coyotes (Canis latrans) in 1995. Survival was not different (P > 0.05) between sites or sexes, regardless of model. We recommend routine use of outdoor pens for prerelease conditioning of black-footed ferret kits.

The effects of MgADP on cross-bridge kinetics: a laser flash photolysis study of guinea-pig smooth muscle.

PubMed Central

Nishiye, E; Somlyo, A V; Török, K; Somlyo, A P

1993-01-01

1. The effects of MgADP on cross-bridge kinetics were investigated using laser flash photolysis of caged ATP (P3-1(2-nitrophenyl) ethyladenosine 5'-triphosphate), in guinea-pig portal vein smooth muscle permeabilized with Staphylococcus aureus alpha-toxin. Isometric tension and in-phase stiffness transitions from rigor state were monitored upon photolysis of caged ATP. The estimated concentration of ATP released from caged ATP by high-pressure liquid chromatography (HPLC) was 1.3 mM. 2. The time course of relaxation initiated by photolysis of caged ATP in the absence of Ca2+ was well fitted during the initial 200 ms by two exponential functions with time constants of, respectively, tau 1 = 34 ms and tau 2 = 1.2 s and relative amplitudes of 0.14 and 0.86. Multiple exponential functions were needed to fit longer intervals; the half-time of the overall relaxation was 0.8 s. The second order rate constant for cross-bridge detachment by ATP, estimated from the rate of initial relaxation, was 0.4-2.3 x 10(4) M-1 s-1. 3. MgADP dose dependently reduced both the relative amplitude of the first component and the rate constant of the second component of relaxation. Conversely, treatment of muscles with apyrase, to deplete endogenous ADP, increased the relative amplitude of the first component. In the presence of MgADP, in-phase stiffness decreased during force maintenance, suggesting that the force per cross-bridge increased. The apparent dissociation constant (Kd) of MgADP for the cross-bridge binding site, estimated from its concentration-dependent effect on the relative amplitude of the first component, was 1.3 microM. This affinity is much higher than the previously reported values (50-300 microM for smooth muscle; 18-400 microM for skeletal muscle; 7-10 microM for cardiac muscle). It is possible that the high affinity reflects the properties of a state generated during the co-operative reattachment cycle, rather than that of the rigor bridge. 4. The rate constant of MgADP release from cross-bridges, estimated from its concentration-dependent effect on the rate constant of the second (tau 2) component, was 0.35-7.7 s-1. To the extent that reattachment of cross-bridges could slow relaxation even during the initial 200 ms, this rate constant may be an underestimate. 5. Inorganic phosphate (Pi, 30 mM) did not affect the rate of relaxation during the initial approximately 50 ms, but accelerated the slower phase of relaxation, consistent with a cyclic cross-bridge model in which Pi increases the proportion of cross-bridges in detached ('weakly bound') states.(ABSTRACT TRUNCATED AT 400 WORDS) Images Fig. 1 PMID:8487195

Are movies with tobacco, alcohol, drugs, sex, and violence rated for youth? A comparison of rating systems in Argentina, Brazil, Mexico, and the United States.

PubMed

Thrasher, James F; Sargent, James D; Vargas, Rosa; Braun, Sandra; Barrientos-Gutierrez, Tonatiuh; Sevigny, Eric L; Billings, Deborah L; Arillo-Santillán, Edna; Navarro, Ashley; Hardin, James

2014-03-01

This study aimed to determine between-country differences and changes over time in the portrayal of youth risk behaviors in films rated for youth in Argentina, Brazil, Mexico and the United States. Content and ratings were analyzed for 362 films that were popular across all four countries from 2002 to 2009. Country-specific ratings were classified as either youth or adult, and Generalized Estimating Equations were used to determine between-country differences in the presence of tobacco, alcohol, drugs, sexual content, and violence in youth-rated films. Within-country differences in this content over time were also assessed, comparing films released from 2002 to 2005 with those released from 2006 to 2009. In the US, films rated for youth were less likely to contain all five risk behaviors than in youth-rated films in Argentina, Brazil, and, when the "15 and older" rating was considered a youth rating, in Mexico. All three Latin American countries "downrated" films that received an adult rating in the US. Nevertheless, tobacco and drug use in youth-rated films declined over time in all countries, whereas moderate to extreme alcohol use and violence involving children or youth increased in all countries. Tobacco and drug use have declined in popular US films, but these behaviors are still prevalent in films rated for youth across the Americas. The apparent success of advocacy efforts to reduce tobacco and other drugs in films suggests that similar efforts be directed to reduce alcohol portrayals. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Compliance Monitoring of Juvenile Yearling Chinook Salmon and Steelhead Survival and Passage at The Dalles Dam, Spring 2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlson, Thomas J.; Skalski, John R.

2010-10-01

The purpose of this compliance study was to estimate dam passage survival of yearling Chinook salmon and steelhead smolts at The Dalles Dam during spring 2010. Under the 2008 Federal Columbia River Power System (FCRPS) Biological Opinion (BiOp), dam passage survival should be greater than or equal to 0.96 and estimated with a standard error (SE) less than or equal 0.015. The study also estimated smolt passage survival from the forebay boat-restricted zone (BRZ) to the tailrace BRZ at The Dalles Dam, as well as the forebay residence time, tailrace egress, and spill passage efficiency (SPE), as required in themore » Columbia Basin Fish Accords. A virtual/paired-release design was used to estimate dam passage survival at The Dalles Dam. The approach included releases of acoustic-tagged smolts above John Day Dam that contributed to the formation of a virtual release at the face of The Dalles Dam. A survival estimate from this release was adjusted by a paired release below The Dalles Dam. A total of 4,298 yearling Chinook salmon and 4,309 steelhead smolts were tagged and released in the investigation. The Juvenile Salmon Acoustic Telemetry System (JSATS) tag model number ATS-156dB, weighing 0.438 g in air, was used in this investigation. The dam passage survival results are summarized as follows: Yearling Chinook Salmon 0.9641 (SE = 0.0096) and Steelhead 0.9535 (SE = 0.0097).« less

The output per stimulus of acetylcholine from cerebral cortical slices in the presence or absence of cholinesterase inhibition

PubMed Central

Bourdois, P.S.; Mitchell, J.F.; Somogyi, G.T.; Szerb, J.C.

1974-01-01

1 The release of endogenous acetylcholine (ACh) from cerebral cortical slices stimulated at 0.25, 1, 4, 16 and 64 Hz was measured in the presence either of physostigmine or of physostigmine and atropine. 2 Atropine potentiated the evoked release of endogenous ACh especially at low frequencies resulting in an output per stimulus which sharply declined with increasing frequency of stimulation, while in the absence of atropine the output of ACh per stimulus was low and fairly constant. 3 The evoked release of [3H]-ACh per stimulus following the incubation of the slices with [3H]-choline, as estimated by means of rate constants of the evoked release of total radioactivity, showed a frequency dependence similar to endogenous ACh when the two were tested under identical conditions. 4 In the absence of an anticholinesterase the evoked release of [3H]-ACh per stimulus was dependent on frequency of stimulation in a similar way to that in the presence of physostigmine and atropine. 5 Results suggest that under physiological conditions, i.e. in the absence of an anti-cholinesterase, the release of ACh per stimulus decreases with increasing frequency of stimulation and that this decrease is due to a lag in the mobilization of stored ACh rather than in the synthesis of new ACh. PMID:4455327

Influence of mastication rate on dynamic flavour release analysed by combined model mouth/proton transfer reaction-mass spectrometry

NASA Astrophysics Data System (ADS)

van Ruth, Saskia M.; Buhr, Katja

2004-12-01

The influence of mastication rate on the dynamic release of seven volatile flavour compounds from sunflower oil was evaluated by combined model mouth/proton transfer reaction-mass spectrometry (PTR-MS). Air/oil partition coefficients were measured by static headspace gas chromatography. The dynamic release of the seven volatile flavour compounds from sunflower oil was significantly affected by the compounds' hydrophobicity and the mastication rate employed in the model mouth. The more hydrophobic compounds were released at a higher rate than their hydrophilic counterparts. Increase in mastication rate increased the maximum concentration measured by 36% on average, and the time to reach this maximum by 35% on average. Mastication affected particularly the release of the hydrophilic compounds. The maximum concentration of the compounds correlated significantly with the compounds' air/oil partition coefficients. The initial release rates over the first 15 s were affected by the type of compound, but not by the mastication rate. During the course of release, the proportions of the hydrophilic compounds to the overall flavour mixture in air decreased. The contribution of the hydrophobic compounds increased. Higher mastication rates, however, increased the proportions of the hydrophilic compounds and decreased those of the hydrophobic compounds.

Heat release rate of wood-plastic composites

Treesearch

N. M. Stark; R. H. White; C. M. Clemons

1997-01-01

Wood-plastic composites are becoming more important as a material that fulfills recycling needs. In this study, fire performance tests were conducted on several compositions of wood and plastic materials using the Ohio State University rate of heat release apparatus. Test results included five-minute average heat release rate in kW/m2 (HRR avg) and maximum heat release...

Demographics of an experimentally released population of elk in Great Smoky Mountains National Park

USGS Publications Warehouse

Murrow, Jennifer L.; Clark, Joseph D.; Delozier, E. Kim

2009-01-01

We assessed the potential for reestablishing elk (Cervus elaphus) in Great Smoky Mountains National Park (GSMNP), USA, by estimating vital rates of experimentally released animals from 2001 to 2006. Annual survival rates for calves ranged from 0.333 to 1.0 and averaged 0.592. Annual survival for subadult and adult elk (i.e., ≥1 yr of age) ranged from 0.690 to 0.933, depending on age and sex. We used those and other vital rates to model projected population growth and viability using a stochastic individual-based model. The annual growth rate (λ) of the modeled population over a 25-year period averaged 0.996 and declined from 1.059 the first year to 0.990 at year 25. The modeled population failed to attain a positive 25-year mean growth rate in 46.0% of the projections. Poor calf recruitment was an important determinant of low population growth. Predation by black bears (Ursus americanus) was the dominant calf mortality factor. Most of the variance of growth projections was due to demographic variation resulting from the small population size (n  =  61). Management actions such as predator control may help increase calf recruitment, but our projections suggest that the GSMNP elk population may be at risk for some time because of high demographic variation.

Regional climatic effects of atmospheric SO2 on Mars

NASA Technical Reports Server (NTRS)

Postawko, S. E.; Fanale, F. P.

1992-01-01

The conditions under which the valley networks on Mars may have formed remains controversial. The magnitude of an atmospheric greenhouse effect by an early massive CO2 atmosphere has recently been questioned by Kasting. Recent calculations indicate that if solar luminosity were less than about 86 percent of its current value, formation of CO2 clouds in the Martian atmosphere would depress the atmospheric lapse rate and reduce the magnitude of surface warming. In light of recent revisions of magma generation on Mars during each Martian epoch, and the suggestions by Wanke et al. that the role of liquid SO2 should be more carefully explored, we have recalculated the potential greenhouse warming by atmospheric SO2 on Mars, with an emphasis on more localized effects. In the vicinity of an active eruption, the concentration of atmospheric SO2 will be higher than if it is assumed that the erupted SO2 is instantaneously globally distributed. The local steady-state concentration of SO2 is a function of the rate at which it is released, its atmospheric lifetime, and the rate at which local winds act to disperse the SO2. We have made estimates of eruption rates, length of eruption, and dispersion rates of volcanically released SO2, for a variety of atmospheric conditions and atmospheric lifetimes of SO2 to explore the maximum regional climatic effect of SO2.

Noble Gas Release Signal as a Precursor to Fracture

NASA Astrophysics Data System (ADS)

Bauer, S. J.; Lee, H.; Gardner, W. P.

2017-12-01

We present empirical results of rock strain, microfracturing, acoustic emissions, and noble gas release from laboratory triaxial experiments for a granite, basalt, shale and bedded rock salt. Noble gases are released and measured real-time during deformation using mass spectrometry. The gas release represents a precursive signal to macrofracture. Gas release is associated with increased acoustic emissions indicating that microfracturing is required to release gas and create pathways for the gas to be sensed. The gas released depends on initial gas content, pore structure and its evolution during deformation, the deformation amount, matrix permeability, deformation style and the stress/strain history. Gases are released from inter and intracrystalline sites; release rate increases as strain and microfracturing increases. The gas composition depends on lithology, geologic history and age, fluids present, and radioisotope concentrations that affect radiogenic noble gas isotope (e.g. 4He,40Ar) production. Noble gas emission and its relationship to crustal processes such as seismicity and volcanism, tectonic velocities, qualitative estimates of deep permeability, age dating of groundwater, and a signature of nuclear weapon detonation. Our result show that mechanical deformation of crustal materials is an important process controlling gas release from rocks and minerals, and should be considered in techniques which utilize gas release and/or accumulation. We propose using noble gas release to signal rock deformation in boreholes, mines and waste repositories. We postulate each rock exhibits a gas release signature which is microstructure, stress, strain, and/or permanent deformation dependent. Calibration of such relationships, for example relating gas release per rock unit volume to strain may be used to quantify rock deformation and develop predictive models.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525. SAND2017-7823A

Latent Heating Structures Derived from TRMM

NASA Technical Reports Server (NTRS)

Tao, W.-K.; Smith, E. A.; Adler, R.; Hou, A.; Kakar, R.; Krishnamurti, T.; Kummerow, C.; Lang, S.; Olson, W.; Satoh, S.

2004-01-01

Rainfall is the fundamental variable within the Earth's hydrological cycle because it is both the main forcing term leading to variations in continental and oceanic surface water budgets. The vertical distribution of latent heat release, which is accompanied with rain, modulates large-scale meridional and zonal circulations within the tropics as well as modifying the energetic efficiency of mid-latitude weather systems. Latent heat release itself is a consequence of phase changes between the vapor, liquid, and frozen states of water.This paper focuses on the retrieval of latent heat release from satellite measurements generated by the Tropical Rainfall Measuring Mission 0. The TRMM observatory, whose development was a joint US-Japan space endeavor, was launched in November 1997. TRMM measurements provide an accurate account of rainfall over the global tropics, information which can be .used to estimate the four-dimensional structure of latent heating across the entire tropical and sub-tropical regions. Various algorithm methodologies for estimating latent heating based on rain rate measurements from TRMM observations are described. The strengths and weaknesses of these algorithms, as well as the latent heating products generated by these algorithms, are also discussed along with validation analyses of the products. The investigation paper provides an overview of how TRMM-derived latent heating information is currently being used in conjunction with global weather and climate models, and concludes with remarks designed to stimulate further research on latent heating retrieval

The effect of the molecular orientation on the release of antimicrobial substances from uniaxially drawn polymer matrixes.

PubMed

Iconomopoulou, S M; Voyiatzis, G A

2005-03-21

A new method of controlled release of low molecular weight biocides incorporated in polymer matrixes is described. The molecular orientation of uniaxially drawn biocide doped polymer films is suggested as a significant parameter for controlled release monitoring. Triclosan, a well-established widespread antibacterial agent, has been incorporated into high density polyethylene (HDPE) films that have been subsequently uniaxially drawn at different draw ratios. The molecular orientation developed was estimated utilizing polarized mu-Raman spectra. Biocide incorporated polymer films, drawn at different draw ratios, have been immersed in ethanol-water solutions (EtOH) and in physiological saline. The release of Triclosan out of the polymer matrix was probed with UV-Vis absorption spectroscopy for a period of time up to 15 months. In all cases, although the film surface of the drawn samples exposed to the liquid solution was higher than the undrawn one, the relevant release rate from the drawn specimens was lower than the non-stretched samples depending on the molecular orientation developed during the drawing process. A note is made of the fact that no significant molecular orientation relaxation of the polyethylene films has been observed even after such a long time of immersion of the drawn films in the liquid solutions.

Estimating air chemical emissions from research activities using stack measurement data.

PubMed

Ballinger, Marcel Y; Duchsherer, Cheryl J; Woodruff, Rodger K; Larson, Timothy V

2013-03-01

Current methods of estimating air emissions from research and development (R&D) activities use a wide range of release fractions or emission factors with bases ranging from empirical to semi-empirical. Although considered conservative, the uncertainties and confidence levels of the existing methods have not been reported. Chemical emissions were estimated from sampling data taken from four research facilities over 10 years. The approach was to use a Monte Carlo technique to create distributions of annual emission estimates for target compounds detected in source test samples. Distributions were created for each year and building sampled for compounds with sufficient detection frequency to qualify for the analysis. The results using the Monte Carlo technique without applying a filter to remove negative emission values showed almost all distributions spanning zero, and 40% of the distributions having a negative mean. This indicates that emissions are so low as to be indistinguishable from building background. Application of a filter to allow only positive values in the distribution provided a more realistic value for emissions and increased the distribution mean by an average of 16%. Release fractions were calculated by dividing the emission estimates by a building chemical inventory quantity. Two variations were used for this quantity: chemical usage, and chemical usage plus one-half standing inventory. Filters were applied so that only release fraction values from zero to one were included in the resulting distributions. Release fractions had a wide range among chemicals and among data sets for different buildings and/or years for a given chemical. Regressions of release fractions to molecular weight and vapor pressure showed weak correlations. Similarly, regressions of mean emissions to chemical usage, chemical inventory, molecular weight, and vapor pressure also gave weak correlations. These results highlight the difficulties in estimating emissions from R&D facilities using chemical inventory data. Air emissions from research operations are difficult to estimate because of the changing nature of research processes and the small quantity and wide variety of chemicals used. Analysis of stack measurements taken over multiple facilities and a 10-year period using a Monte Carlo technique provided a method to quantify the low emissions and to estimate release fractions based on chemical inventories. The variation in release fractions did not correlate well with factors investigated, confirming the complexities in estimating R&D emissions.

Contribution by Macroalgal Mats to Primary Production of a Shallow Embayment Under High and Low Nitrogen-loading Rates

NASA Astrophysics Data System (ADS)

Peckol, P.; Rivers, J. S.

1996-09-01

The limits on primary production in areas undergoing eutrophication may be set by indirect effects of nitrogen loading, i.e. decreasing irradiances, associated with proliferating opportunistic algae. Using in situphoton flux density (PFD) availability estimates within unattached algal mats and photosynthetic parameters determined from photosynthesis vs.irradiance (P vs.I) curves generated for the dominant components of mat assemblages, Cladophora vagabundaand Gracilaria tikvahiae, seasonal net mat production rate for estuaries (Waquoit Bay, Massachusetts, U.S.A.) receiving high (Childs River) and low (Sage Lot Pond) N-loading rates were determined. Although abundance of C. vagabundawas 2× greater than G. tikvahiae, the former species contributed only about 50% of total mat productivity, due largely to rapid light attenuation within the dense algal mat. While mat production was low and similar at both sides during winter (≈0·35 g C m -2 day -1), for other seasons, the net mat daytime productivity at Childs River, the N-loaded site, was 2·5× higher than rates determined for Sage Lot Pond. Although annual net daytime production at Childs River (1094 g C m -2 year -1) was comparable to estimates for other algal mat assemblages in eutrophic systems, primary production of the Waquoit Bay system was found to become self-limiting as available PFD controls maximum productivity. In photosynthetically inactive portions of the algal mat, carbon release was estimated from tissue-loss measurements at 0·14 g C m -2 day -1for C. vagabundaand 0·05 g C m -2 day -1for G. tikvahiae. Annual in situC release of 73 g C m -2is ≈20% of annual net mat production (fixed carbon not respired by algae) in this embayment. Although both estuaries showed net autotrophy year round (Pg:R>1), the high metabolic cost of a large, inactive mat resulted in lower Pg:R ratios at Childs Rivers than at Sage Lot Pond, particularly during the summer period of peak production. Thus, it is predicted that the Waquoit Bay system will experience an overall decline in Pg:R ratios and consequent increase in anoxic events as eutrophication continues.

Burning rate of solid wood measured in a heat release rate calorimeter

Treesearch

H. C. Tran; R. H. White

1992-01-01

Burning rate is a key factor in modeling fire growth and fire endurance of wood structures. This study investigated the burning rate of selected wood materials as determined by heat release, mass loss and charring rates. Thick samples of redwood, southern pine, red oak and basswood were tested in a heat release rate calorimeter. Results on ignitability and average beat...

Combined Experimental and Computational Approach to Predict the Glass-Water Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, Eric M.; Bacon, Diana H.

2011-10-01

The use of mineral and glass dissolution rates measured in laboratory experiments to predict the weathering of primary minerals and volcanic and nuclear waste glasses in field studies requires the construction of rate models that accurately describe the weathering process over geologic timescales. Additionally, the need to model the long-term behavior of nuclear waste glass for the purpose of estimating radionuclide release rates requires that rate models be validated with long-term experiments. Several long-term test methods have been developed to accelerate the glass-water reaction [drip test, vapor hydration test, product consistency test B, and pressurized unsaturated flow (PUF)], thereby reducingmore » the duration required to evaluate long-term performance. Currently, the PUF test is the only method that mimics the unsaturated hydraulic properties expected in a subsurface disposal facility and simultaneously monitors the glass-water reaction. PUF tests are being conducted to accelerate the weathering of glass and validate the model parameters being used to predict long-term glass behavior. A one-dimensional reactive chemical transport simulation of glass dissolution and secondary phase formation during a 1.5-year-long PUF experiment was conducted with the Subsurface Transport Over Reactive Multiphases (STORM) code. Results show that parameterization of the computer model by combining direct bench scale laboratory measurements and thermodynamic data provides an integrated approach to predicting glass behavior over the length of the experiment. Over the 1.5-year-long test duration, the rate decreased from 0.2 to 0.01 g/(m2 day) based on B release for low-activity waste glass LAWA44. The observed decrease is approximately two orders of magnitude higher than the decrease observed under static conditions with the SON68 glass (estimated to be a decrease by four orders of magnitude) and suggests that the gel-layer properties are less protective under these dynamic conditions.« less

Combined Experimental and Computational Approach to Predict the Glass-Water Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, Eric M; Bacon, Diana

2011-01-01

The use of mineral and glass dissolution rates measured in laboratory experiments to predict the weathering of primary minerals and volcanic and nuclear waste glasses in field studies requires the construction of rate models that accurately describe the weathering process over geologic time-scales. Additionally, the need to model the long-term behavior of nuclear waste glass for the purpose of estimating radionuclide release rates requires that rate models are validated with long-term experiments. Several long-term test methods have been developed to accelerate the glass-water reaction [drip test, vapor hydration test, product consistency test-B, and pressurized unsaturated flow (PUF)], thereby reducing themore » duration required to evaluate long-term performance. Currently, the PUF test is the only method that mimics the unsaturated hydraulic properties expected in a subsurface disposal facility and simultaneously monitors the glass-water reaction. PUF tests are being conducted to accelerate the weathering of glass and validate the model parameters being used to predict long-term glass behavior. A one-dimensional reactive chemical transport simulation of glass dissolution and secondary phase formation during a 1.5-year long PUF experiment was conducted with the subsurface transport over reactive multi-phases code. Results show that parameterization of the computer model by combining direct bench-scale laboratory measurements and thermodynamic data provides an integrated approach to predicting glass behavior over the length of the experiment. Over the 1.5-year long test duration, the rate decreased from 0.2 to 0.01 g/(m2 d) base on B release. The observed decrease is approximately two orders of magnitude higher than the decrease observed under static conditions with the SON68 glass (estimated to be a decrease by 4 orders of magnitude) and suggest the gel-layer properties are less protective under these dynamic conditions.« less

Equations for estimating stand establishment, release, and thinning costs in the Lake States.

Treesearch

Jeffrey T. Olson; Allen L. Lundgren; Dietmar Rose

1978-01-01

Equations for estimating project costs for certain silvicultural treatments in the Lake States have been developed from project records of public forests. Treatments include machine site preparation, hand planting, aerial spraying, prescribed burning, manual release, and thinning.

Carbon decomposition process of the residual biomass in the paddy soil of a single-crop rice field

NASA Astrophysics Data System (ADS)

Okada, K.; Iwata, T.

2014-12-01

In cultivated fields, residual organic matter is plowed into soil after harvest and decaying in fallow season. Greenhouse gases such as CO2 and CH4 is generated by the decomposition of the substantial organic matter and released into the atmosphere. In some fields, open burning is carried out by tradition, when carbon in residual matter is released into atmosphere as CO2. However, burning effect on carbon budget between crop lands and atmosphere is not entirely considered yet. In this study, coarse organic matter (COM) in paddy soil of a single-crop rice field was sampled on regular intervals between January, 2011 and August, 2014 The amount of carbon release from residual matter was estimated by analyzing of the variations in carbon content of COM. Effects of soil temperature (Ts) and soil water content (SWC) at the paddy field on the rate of carbon decomposition was investigated. Though decreasing rate of COM was much smaller in winter season, it is accelerated at the warming season between April and June every year. Decomposition was resisted for next rice cultivated season despite of highest soil temperature. In addition, the observational field was divided into two areas, and three time open burning experiments were conducted in November, 2011, 2012, and 2013. In each year, three sampling surveys, or plants before harvest and residuals before and after the burning experiment, were done. From these surveys, it is suggested that about 48±2% of carbon contents of above-ground plant was yield out as grain by harvest, and about 27±2% of carbon emitted as CO2 by burning. Carbon content of residuals plowed into soil after the harvest was estimated 293±1 and 220±36gC/m2 in no-burned and burned area, respectively, based on three-years average. It is estimated that 70 and 60% of the first input amount of COM was decomposed after a year in no-burned and burned area, respectively.

Near-source mobile methane emission estimates using EPA Method33a and a novel probabilistic approach as a basis for leak quantification in urban areas

NASA Astrophysics Data System (ADS)

Albertson, J. D.

2015-12-01

Methane emissions from underground pipeline leaks remain an ongoing issue in the development of accurate methane emission inventories for the natural gas supply chain. Application of mobile methods during routine street surveys would help address this issue, but there are large uncertainties in current approaches. In this paper, we describe results from a series of near-source (< 30 m) controlled methane releases where an instrumented van was used to measure methane concentrations during both fixed location sampling and during mobile traverses immediately downwind of the source. The measurements were used to evaluate the application of EPA Method 33A for estimating methane emissions downwind of a source and also to test the application of a new probabilistic approach for estimating emission rates from mobile traverse data.

Hard choices in assessing survival past dams — a comparison of single- and paired-release strategies

USGS Publications Warehouse

Zydlewski, Joseph D.; Stich, Daniel S.; Sigourney, Douglas B.

2017-01-01

Mark–recapture models are widely used to estimate survival of salmon smolts migrating past dams. Paired releases have been used to improve estimate accuracy by removing components of mortality not attributable to the dam. This method is accompanied by reduced precision because (i) sample size is reduced relative to a single, large release; and (ii) variance calculations inflate error. We modeled an idealized system with a single dam to assess trade-offs between accuracy and precision and compared methods using root mean squared error (RMSE). Simulations were run under predefined conditions (dam mortality, background mortality, detection probability, and sample size) to determine scenarios when the paired release was preferable to a single release. We demonstrate that a paired-release design provides a theoretical advantage over a single-release design only at large sample sizes and high probabilities of detection. At release numbers typical of many survival studies, paired release can result in overestimation of dam survival. Failures to meet model assumptions of a paired release may result in further overestimation of dam-related survival. Under most conditions, a single-release strategy was preferable.

The relationship between functional sciatic nerve block duration and the rate of release of lidocaine from a controlled-release matrix.

PubMed

Gerner, Peter; Wang, Chi-Fei; Lee, Byung-Sang; Suzuki, Suzuko; Degirolami, Umberto; Gandhi, Ankur; Knaack, David; Strichartz, Gary

2010-07-01

Nerve blocks of long duration are often desirable in perioperative and postoperative situations. The relationship between the duration of such blocks and the rate at which a local anesthetic is released is important to know for developing a localized drug delivery system that will optimize block duration. Lidocaine concentration was varied in 1 series of formulations (OSB-L) containing a constant amount of release rate modifier. In another series (OST-R), the release rate modifier was varied while the lidocaine content was held constant. Release kinetics were measured in vitro and correlated to the in vivo duration of antinociceptive and motor block effects when the formulation was implanted next to the rat sciatic nerve. In parallel studies, rats receiving different formulations of slow-release lidocaine were fixed by intracardiac perfusion with 4% paraformaldehyde and nerve-muscle tissue taken for histopathological analysis. In this study, we have demonstrated that the most important variable for effecting functional nerve block, i.e., the blockade of impulses in the relevant fibers of the sciatic nerve, is the rate of lidocaine release at that time. For the OSB-L formulations (lidocaine concentrations of 1.875%, 3.75%, 7.5%, and 15% at a constant release rate modifier of 5%), the average in vitro release rates at 50% recovery of motor block and nociceptive block were 0.91 +/- 0.28 and 1.75 +/- 0.61 mg/h, respectively. For the OST-R formulations (16% lidocaine with release rate modifier concentrations of 1.875%, 3.75%, 7.5%, and 15%), the average in vitro release rates at 50% recovery of motor block and nociceptive block were 2.33 +/- 1.39 and 4.34 +/- 1.09 mg/h, respectively. The OSB-L formulations showed a dose-dependent increase in block duration proportional to an increase in initial lidocaine concentration, whereas the OST-R formulations showed a nonmonotonic relationship between release rate modifier concentration and block duration. The histopathological studies at 24 hours, 3, 5, or 7 days, and 4 weeks after the implantation revealed inflammatory reactions with degrees correlated with lidocaine content, but limited to the connective tissue and muscle immediately surrounding the implanted material. Despite these observed inflammatory reactions, nociceptive and motor block function returned to normal, preimplantation values in all animals. Increasing initial lidocaine content proportionately increased the duration of functional sciatic nerve block. However, decreasing the release rate per se does not give a proportional increase in block duration. Instead, there seems to be an optimal, intermediate release rate for achieving the maximum duration of block.

Fission-gas-release rates from irradiated uranium nitride specimens

NASA Technical Reports Server (NTRS)

Weinstein, M. B.; Kirchgessner, T. A.; Tambling, T. N.

1973-01-01

Fission-gas-release rates from two 93 percent dense UN specimens were measured using a sweep gas facility. Specimen burnup rates averaged .0045 and .0032 percent/hr, and the specimen temperatures ranged from 425 to 1323 K and from 552 to 1502 K, respectively. Burnups up to 7.8 percent were achieved. Fission-gas-release rates first decreased then increased with burnup. Extensive interconnected intergranular porosity formed in the specimen operated at over 1500 K. Release rate variation with both burnup and temperature agreed with previous irradiation test results.

Individualized optimal release angles in discus throwing.

PubMed

Leigh, Steve; Liu, Hui; Hubbard, Mont; Yu, Bing

2010-02-10

The purpose of this study was to determine individualized optimal release angles for elite discus throwers. Three-dimensional coordinate data were obtained for at least 10 competitive trials for each subject. Regression relationships between release speed and release angle, and between aerodynamic distance and release angle were determined for each subject. These relationships were linear with subject-specific characteristics. The subject-specific relationships between release speed and release angle may be due to subjects' technical and physical characteristics. The subject-specific relationships between aerodynamic distance and release angle may be due to interactions between the release angle, the angle of attack, and the aerodynamic distance. Optimal release angles were estimated for each subject using the regression relationships and equations of projectile motion. The estimated optimal release angle was different for different subjects, and ranged from 35 degrees to 44 degrees . The results of this study demonstrate that the optimal release angle for discus throwing is thrower-specific. The release angles used by elite discus throwers in competition are not necessarily optimal for all discus throwers, or even themselves. The results of this study provide significant information for understanding the biomechanics of discus throwing techniques. Copyright 2009 Elsevier Ltd. All rights reserved.

[Economic impact of overactive bladder symptoms in Japan].

PubMed

Inoue, Sachie; Kobayashi, Makoto; Sugaya, Kimio

2008-11-01

Overactive bladder (OAB) is characterized by involuntary contractions of the detrusor muscles of the bladder. The primary symptoms of OAB include urinary urgency and frequency, with or without urge incontinence. Despite the growing awareness of OAB as a chronic medical condition, little is known about the disease's economic burden. Therefore, in the present study, the costs associated with the management of OAB symptoms in Japan were estimated, and the potential cost saving by increasing the rate of physician visits in OAB population was analyzed. To estimate the costs of OAB symptoms in Japan, we collected a variety of epidemiologic and economic literatures about OAB or urinary incontinence published by June, 2007. Three types of costs were considered in this estimation: 1. OAB treatment cost (pharmacological treatment cost, diagnostic cost and cost for physician visits), 2. direct cost (OAB-related cost [urinary tract infections, skin infections and fractures] and incontinence care cost [costs of pads, diapers and cleaning]), and 3. indirect cost (work loss due to absence from work and decrease in productivity). The analysis was conducted on community dwelling Japanese persons aged > or = 40 years, and assumed that OAB patients visited a hospital or a clinic once every four weeks. For the estimation of pharmacological treatment cost, four anticholinergic drugs (immediate-release oxybutynin (Pollakisu), propiverine (BUP-4), extended-release tolterodine (Detrusitol) and solifenacin (Vesicare)) were referred. Potential cost saving was estimated on the assumption that the hospital visit rate would increase from the current 22.7% to 35% and 50%, respectively. The number of persons with OAB symptoms and OAB patients was estimated at 8.6 million (4.6 million men, 4.0 million women) and 2.0 million (1.7 million men, 0.3 million women), respectively. The annual cost for OAB was estimated to be 956.2 billion yen (112,000 yen per one person with OAB symptoms). This cost included 180.9 billion yen (19%) for OAB treatment cost (including medication of 159.1 billion yen), 62 billion yen (6%) for OAB-related cost, 28.7 billion yen (3%) for incontinence care cost and 684.6 billion yen (72%) for work loss. Therefore, the cost for work loss accounted for the majority of OAB cost. The potential annual cost saving was estimated at 92.7 billion yen and 205.8 billion yen for the assumed hospital visit rate of 35% and 50%, respectively, and 88,000 yen per newly visiting OAB patient. It was revealed that the economic impact imposed by OAB was enormous. It might be possible to reduce the cost for OAB by appropriate treatment for OAB population.

Comparison of catch and lake trout bycatch in commercial trap nets and gill nets targeting lake whitefish in northern Lake Huron

USGS Publications Warehouse

Johnson, James E.; Ebener, Mark P.; Gebhardt, Kenneth; Bergstedt, Roger

2004-01-01

We compared seasonal lake whitefish catch rates, lake trout bycatch, and gearinduced lake trout mortality between commercial trap nets and gill nets in north-central Lake Huron. Onboard monitors recorded catches from 260 gill net and 96 trap net lifts from October 1998 through December 1999. Catch rates for lake whitefish were highest in fall for both gear types, reflecting proximity of spawning sites to the study area. Lake whitefish catch rates were also relatively high in spring but low in both gear types in summer. Lake trout were the principal bycatch species in both gears. The lake trout bycatch was lowest in both gear types in fall, highest in gill nets in spring, and highest in trap nets in summer. The ratio of lake trout to legal whitefish (the target species) was highest in summer and lowest in fall in both gear types. The high lake trout ratio in summer was due principally to low catch rates of lake whitefish. All but 3 of 186 live lake trout removed from trap net pots survived for at least two days of observation in laboratory tanks. Therefore, we estimated that post-release survival of trap netted lake trout that had not been entangled in the mesh was 98.4%. In addition, we accounted for stress-induced mortality for lake trout that were live at capture but entangled in the mesh of either gear type. Resulting estimates of lake trout survival were higher in trap nets (87.8%) than in gill nets (39.6%). The number of lake trout killed per lift was highest during summer in trap nets and during spring in gill nets. In trap nets, 85% of dead lake trout were observed to be entangled in the mesh of the pot or tunnels. Survival rates of lake trout in gill nets were higher in our study than reported by others, probably because our nets were hand lifted in a small boat. Our trap net-induced mortality estimates on lake trout were higher than those reported by others because we adjusted our estimates to account for post-release mortality caused by handling and injury. Studies such as ours should prove useful to managers developing harvest allocation options that are consistent with the need to protect nontarget populations. For example, applying our seasonal lake trout-whitefish catch ratios to a hypothetical small-boat gill net fishery, the lake trout bycatch from harvest of 100,000 kg of whitefish would equal the estimated lake trout production available for harvest in the study area for year 2002. The two trap net fisheries may have incidentally killed half this number of lake trout annually from 1995-99. Bycatch estimates are also important inputs to catch-at-age decision models used in developing rehabilitation and harvest strategies for target and bycatch species.

Analysis of Radionuclide Releases from the Fukushima Dai-ichi Nuclear Power Plant Accident Part II

NASA Astrophysics Data System (ADS)

Achim, Pascal; Monfort, Marguerite; Le Petit, Gilbert; Gross, Philippe; Douysset, Guilhem; Taffary, Thomas; Blanchard, Xavier; Moulin, Christophe

2014-03-01

The present part of the publication (Part II) deals with long range dispersion of radionuclides emitted into the atmosphere during the Fukushima Dai-ichi accident that occurred after the March 11, 2011 tsunami. The first part (Part I) is dedicated to the accident features relying on radionuclide detections performed by monitoring stations of the Comprehensive Nuclear Test Ban Treaty Organization network. In this study, the emissions of the three fission products Cs-137, I-131 and Xe-133 are investigated. Regarding Xe-133, the total release is estimated to be of the order of 6 × 1018 Bq emitted during the explosions of units 1, 2 and 3. The total source term estimated gives a fraction of core inventory of about 8 × 1018 Bq at the time of reactors shutdown. This result suggests that at least 80 % of the core inventory has been released into the atmosphere and indicates a broad meltdown of reactor cores. Total atmospheric releases of Cs-137 and I-131 aerosols are estimated to be 1016 and 1017 Bq, respectively. By neglecting gas/particulate conversion phenomena, the total release of I-131 (gas + aerosol) could be estimated to be 4 × 1017 Bq. Atmospheric transport simulations suggest that the main air emissions have occurred during the events of March 14, 2011 (UTC) and that no major release occurred after March 23. The radioactivity emitted into the atmosphere could represent 10 % of the Chernobyl accident releases for I-131 and Cs-137.

Effect of mean diameter and polydispersity of PLG microspheres on drug release: experiment and theory.

PubMed

Berchane, N S; Carson, K H; Rice-Ficht, A C; Andrews, M J

2007-06-07

The need to tailor release rate profiles from polymeric microspheres is a significant problem. Microsphere size, which has a significant effect on drug release rate, can potentially be varied to design a controlled drug delivery system with desired release profile. In this work the effects of microspheres mean diameter, polydispersity, and polymer degradation on drug release rate from poly(lactide-co-glycolide) (PLG) microspheres are described. Piroxicam containing PLG microspheres were fabricated at 20% loading, and at three different impeller speeds. A portion of the microspheres was then sieved giving five different size distributions. In vitro release kinetics were determined for each preparation. Based on these experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the microsphere size was increased. The mathematical model gave a good fit to the experimental release data. For highly polydisperse populations (polydispersity parameter b<3), incorporating the microsphere size distribution into the mathematical model gave a better fit to the experimental results than using the representative mean diameter. The validated mathematical model can be used to predict small-molecule drug release from PLG microsphere populations.

Effect of Quaternary Ammonium Carboxymethylchitosan on Release Rate In-vitro of Aspirin Sustained-release Matrix Tablets

PubMed Central

Meng, Lingbin; Teng, Zhongqiu; Zheng, Nannan; Meng, Weiwei; Dai, Rongji; Deng, Yulin

2013-01-01

The aim of this study was to develop a derivative of chitosan as pharmaceutical excipient used in sustained-release matrix tablets of poorly soluble drugs. A water-soluble quaternary ammonium carboxymethylchitosan was synthesized by a two-step reaction with carboxymethylchitosan (CMCTS), decylalkyl dimethyl ammonium and epichlorohydrin. The elemental analysis showed that the target product with 10.27% of the maximum grafting degree was obtained. To assess the preliminary safety of this biopolymer, cell toxicity assay was employed. In order to further investigate quaternary ammonium carboxymethylchitosan application as pharmaceutical excipient, aspirin was chosen as model drug. The effect of quaternary ammonium CMCTS on aspirin release rate from sustained-release matrix tablets was examined by in-vitro dissolution experiments. The results showed that this biopolymer had a great potential in increasing the dissolution of poorly soluble drug. With the addition of CMCTS-CEDA, the final cumulative release rate of drug rose up to 90%. After 12 h, at the grade of 10, 20 and 50 cps, the drug release rate increased from 58.1 to 90.7%, from 64.1 to 93.9%, from 69.3 to 96.1%, respectively. At the same time, aspirin release rate from sustainedrelease model was found to be related to the amount of quaternary ammonium CMCTS employed. With the increase of CMCTS-CEDA content, the accumulated release rate increased from 69.1% to 86.7%. The mechanism of aspirin release from sustained-release matrix tablets was also preliminary studied to be Fick diffusion. These data demonstrated that the chitosan derivative has positive effect on drug release from sustained-release matrix tablets. PMID:24250627

Plutonium release from the 903 pad at Rocky Flats.

PubMed

Mongan, T R; Ripple, S R; Winges, K D

1996-10-01

The Colorado Department of Public Health and Environment (CDH) sponsored a study to reconstruct contaminant doses to the public from operations at the Rocky Flats nuclear weapons plant. This analysis of the accidental release of plutonium from the area known as the 903 Pad is part of the CDH study. In the 1950's and 1960's, 55-gallon drums of waste oil contaminated with plutonium, and uranium were stored outdoors at the 903 Pad. The drums corroded, leaking contaminated oil onto soil subsequently carried off-site by the wind. The plutonium release is estimated using environmental data from the 1960's and 1970's and an atmospheric transport model for fugitive dust. The best estimate of total plutonium release to areas beyond plant-owned property is about 0.26 TBq (7 Ci). Off-site airborne concentrations and deposition of plutonium are estimated for dose calculation purposes. The best estimate of the highest predicted off-site effective dose is approximately 72 microSv (7.2 mrem).

Large, Moderate or Small? The Challenge of Measuring Mass Eruption Rates in Volcanic Eruptions

NASA Astrophysics Data System (ADS)

Gudmundsson, M. T.; Dürig, T.; Hognadottir, T.; Hoskuldsson, A.; Bjornsson, H.; Barsotti, S.; Petersen, G. N.; Thordarson, T.; Pedersen, G. B.; Riishuus, M. S.

2015-12-01

The potential impact of a volcanic eruption is highly dependent on its eruption rate. In explosive eruptions ash may pose an aviation hazard that can extend several thousand kilometers away from the volcano. Models of ash dispersion depend on estimates of the volcanic source, but such estimates are prone to high error margins. Recent explosive eruptions, including the 2010 eruption of Eyjafjallajökull in Iceland, have provided a wealth of data that can help in narrowing these error margins. Within the EU-funded FUTUREVOLC project, a multi-parameter system is currently under development, based on an array of ground and satellite-based sensors and models to estimate mass eruption rates in explosive eruptions in near-real time. Effusive eruptions are usually considered less of a hazard as lava flows travel slower than eruption clouds and affect smaller areas. However, major effusive eruptions can release large amounts of SO2 into the atmosphere, causing regional pollution. In very large effusive eruptions, hemispheric cooling and continent-scale pollution can occur, as happened in the Laki eruption in 1783 AD. The Bárdarbunga-Holuhraun eruption in 2014-15 was the largest effusive event in Iceland since Laki and at times caused high concentrations of SO2. As a result civil protection authorities had to issue warnings to the public. Harmful gas concentrations repeatedly persisted for many hours at a time in towns and villages at distances out to 100-150 km from the vents. As gas fluxes scale with lava fluxes, monitoring of eruption rates is therefore of major importance to constrain not only lava but also volcanic gas emissions. This requires repeated measurements of lava area and thickness. However, most mapping methods are problematic once lava flows become very large. Satellite data on thermal emissions from eruptions have been used with success to estimate eruption rate. SAR satellite data holds potential in delivering lava volume and eruption rate estimates, although availability and repeat times of radar platforms is still low compared to e.g. the thermal satellites. In the 2014-15 eruption, lava volume was estimated repeatedly from an aircraft-based system that combines radar altimeter with an on-board DGPS, yielding a several estimates of lava volume and time-averaged mass eruption rate.

Comparative Survival Rate Study (CSS) of Hatchery PIT-tagged Chinook; Oregon Department of Fish and Wildlife, Annual Report 2002-2003.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jonasson, Brian

2004-02-01

We PIT-tagged juvenile spring chinook salmon reared at Lookingglass Hatchery in October 2002 as part of the Comparative Survival Rate Study (CSS) for migratory year (MY) 2003. We tagged 20,950 Imnaha stock spring chinook salmon, and after mortality and tag loss, we allowed the remaining 20,904 fish to leave the acclimation pond at our Imnaha River satellite facility beginning 1 April 2003 to begin their seaward migration. The fish remaining in the pond were forced out on 15 April 2003. We tagged 20,820 Catherine Creek stock captive and conventional brood progeny spring chinook salmon, and after mortality and tag loss,more » we allowed the remaining 20,628 fish to leave the acclimation ponds at our Catherine Creek satellite facility beginning during two acclimation periods. The volitional release for the early acclimation group began 12 March 2003, and all remaining fish were forced out of the ponds on 23 March 2003. The volitional release for the late acclimation group began 31 March 2003, and all remaining fish were forced out of the ponds on 14 April 2003. We estimated survival rates, from release to Lower Granite Dam in MY 2003, for three stocks of hatchery spring chinook salmon tagged at Lookingglass Hatchery to determine their relative migration performance. Survival rates for the Imnaha River, Lostine River, and Catherine Creek stocks were 0.714, 0.557, and 0.350, respectively. We PIT-tagged 20,944 BY 2002 Imnaha River stock and 20,980 BY 2002 Catherine Creek stock captive and conventional brood progeny in October and November 2003 as part of the CSS for MY 2004. From tagging to January 28, 2004, the rates of mortality and tag loss for Imnaha River stock were 0.16% and 0.04%, respectively. Catherine Creek stock, during the same period, had rates of mortality and tag loss of 0.19% and 0.06%, respectively.« less

Accurate evaporation rates of pure and doped water clusters in vacuum: A statistico-dynamical approach

NASA Astrophysics Data System (ADS)

Calvo, F.; Douady, J.; Spiegelman, F.

2010-01-01

Unimolecular evaporation of selected pure (H2O)n and heterogeneous (H2O)n-1X+ water clusters containing a single hydronium or ammonium impurity is investigated in the framework of phase space theory (PST) in its orbiting transition state version. Using the many-body polarizable Kozack-Jordan potential and its extensions for X+=H3O+ and NH4+, the thermal evaporation of clusters containing 21 and 50 molecules is simulated at several total energies. Numerous molecular dynamics (MD) trajectories at high internal energies provide estimates of the decay rate constant, as well as the kinetic energy and angular momentum released upon dissociation. Additional Monte Carlo simulations are carried out to determine the anharmonic densities of vibrational states, which combined with suitable forms for the rotational densities of states provide expressions for the energy-resolved differential rates. Successful comparison between the MD results and the independent predictions of PST for the distributions of kinetic energy and angular momentum released shows that the latter statistical approach is quantitative. Using MD data as a reference, the absolute evaporation rates are calculated from PST over broad energy and temperature ranges. Based on these results, the presence of an ionic impurity is generally found to decrease the rate, however the effect is much more significant in the 21-molecule clusters. Our calculations also suggest that due to backbendings in the microcanonical densities of states the variations of the evaporation rates may not be strictly increasing with energy or temperature.

Hindered disulfide bonds to regulate release rate of model drug from mesoporous silica.

PubMed

Nadrah, Peter; Maver, Uroš; Jemec, Anita; Tišler, Tatjana; Bele, Marjan; Dražić, Goran; Benčina, Mojca; Pintar, Albin; Planinšek, Odon; Gaberšček, Miran

2013-05-01

With the advancement of drug delivery systems based on mesoporous silica nanoparticles (MSNs), a simple and efficient method regulating the drug release kinetics is needed. We developed redox-responsive release systems with three levels of hindrance around the disulfide bond. A model drug (rhodamine B dye) was loaded into MSNs' mesoporous voids. The pore opening was capped with β-cyclodextrin in order to prevent leakage of drug. Indeed, in absence of a reducing agent the systems exhibited little leakage, while the addition of dithiothreitol cleaved the disulfide bonds and enabled the release of cargo. The release rate and the amount of released dye were tuned by the level of hindrance around disulfide bonds, with the increased hindrance causing a decrease in the release rate as well as in the amount of released drug. Thus, we demonstrated the ability of the present mesoporous systems to intrinsically control the release rate and the amount of the released cargo by only minor structural variations. Furthermore, an in vivo experiment on zebrafish confirmed that the present model delivery system is nonteratogenic.

Mortality after prison release: opioid overdose and other causes of death, risk factors, and time trends from 1999 to 2009.

PubMed

Binswanger, Ingrid A; Blatchford, Patrick J; Mueller, Shane R; Stern, Marc F

2013-11-05

Among former prisoners, a high rate of death has been documented in the early postrelease period, particularly from drug-related causes. Little is known about risk factors and trends in postrelease mortality in the past decade, especially given general population increases in overdose deaths from pharmaceutical opioids. To determine postrelease mortality between 1999 and 2009; cause-specific mortality rates; and whether sex, calendar year, and custody factors were risk factors for all-cause, overdose, and opioid-related deaths. Cohort study. Prison system of the Washington State Department of Corrections. 76 208 persons released from prison. Identities were linked probabilistically to the National Death Index to identify deaths and causes of death, and mortality rates were calculated. Cox proportional hazards regression estimated the effect of age, sex, race or ethnicity, whether the incarceration resulted from a violation of terms of the person's community supervision, length of incarceration, release type, and calendar year on the hazard ratio (HR) for death. The all-cause mortality rate was 737 per 100 000 person-years (95% CI, 708 to 766) (n = 2462 deaths). Opioids were involved in 14.8% of all deaths. Overdose was the leading cause of death (167 per 100 000 person-years [CI, 153 to 181]), and overdose deaths in former prisoners accounted for 8.3% of the overdose deaths among persons aged 15 to 84 years in Washington from 2000 to 2009. Women were at increased risk for overdose (HR, 1.38 [CI, 1.12 to 1.69]) and opioid-related deaths (HR, 1.39 [CI, 1.09 to 1.79]). The study was done in only 1 state. Innovation is needed to reduce the risk for overdose among former prisoners. National Institute on Drug Abuse and the Robert Wood Johnson Foundation.

The Design and Analysis of Salmonid Tagging Studies in the Columbia Basin : Volume XVII : Effects of Ocean Covariates and Release Timing on First Ocean-Year Survival of Fall Chinook Salmon from Oregon and Washington Coastal Hatcheries.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burgess, Caitlin; Skalski, John R.

2001-05-01

Effects of oceanographic conditions, as well as effects of release-timing and release-size, on first ocean-year survival of subyearling fall chinook salmon were investigated by analyzing CWT release and recovery data from Oregon and Washington coastal hatcheries. Age-class strength was estimated using a multinomial probability likelihood which estimated first-year survival as a proportional hazards regression against ocean and release covariates. Weight-at-release and release-month were found to significantly effect first year survival (p < 0.05) and ocean effects were therefore estimated after adjusting for weight-at-release. Negative survival trend was modeled for sea surface temperature (SST) during 11 months of the year overmore » the study period (1970-1992). Statistically significant negative survival trends (p < 0.05) were found for SST during April, June, November and December. Strong pairwise correlations (r > 0.6) between SST in April/June, April/November and April/December suggest the significant relationships were due to one underlying process. At higher latitudes (45{sup o} and 48{sup o}N), summer upwelling (June-August) showed positive survival trend with survival and fall (September-November) downwelling showed positive trend with survival, indicating early fall transition improved survival. At 45{sup o} and 48{sup o}, during spring, alternating survival trends with upwelling were observed between March and May, with negative trend occurring in March and May, and positive trend with survival occurring in April. In January, two distinct scenarios of improved survival were linked to upwelling conditions, indicated by (1) a significant linear model effect (p < 0.05) showing improved survival with increasing upwelling, and (2) significant bowl-shaped curvature (p < 0.05) of survival with upwelling. The interpretation of the effects is that there was (1) significantly improved survival when downwelling conditions shifted to upwelling conditions in January (i.e., early spring transition occurred, p < 0.05), (2) improved survival during strong downwelling conditions (Bakun units < -250). Survival decreased during weak downwelling conditions (Bakun units between -180 and -100). Strong to moderately strong correlations between January upwelling and April SST (r = 0.5), June SST (r = 0.6), and the North Pacific Index (NPI) of Aleutian Low strength (r > 0.7) suggest January is a period when important effects originate and play out over ensuing months. Significant inverse trend with survival (p < 0.05) was found for Bakun indices in December, indicating strong downwelling improved survival. Higher-than-average adult return rates were observed for cohorts from brood-years 1982-1983, strong El Nino years. Individual hatcheries were found to have unique age-class strength and age-at-return characteristics.« less

Detailed source term estimation of the atmospheric release for the Fukushima Daiichi Nuclear Power Station accident by coupling simulations of atmospheric dispersion model with improved deposition scheme and oceanic dispersion model

NASA Astrophysics Data System (ADS)

Katata, G.; Chino, M.; Kobayashi, T.; Terada, H.; Ota, M.; Nagai, H.; Kajino, M.; Draxler, R.; Hort, M. C.; Malo, A.; Torii, T.; Sanada, Y.

2014-06-01

Temporal variations in the amount of radionuclides released into the atmosphere during the Fukushima Dai-ichi Nuclear Power Station (FNPS1) accident and their atmospheric and marine dispersion are essential to evaluate the environmental impacts and resultant radiological doses to the public. In this paper, we estimate a detailed time trend of atmospheric releases during the accident by combining environmental monitoring data with atmospheric model simulations from WSPEEDI-II (Worldwide version of System for Prediction of Environmental Emergency Dose Information), and simulations from the oceanic dispersion model SEA-GEARN-FDM, both developed by the authors. A sophisticated deposition scheme, which deals with dry and fogwater depositions, cloud condensation nuclei (CCN) activation and subsequent wet scavenging due to mixed-phase cloud microphysics (in-cloud scavenging) for radioactive iodine gas (I2 and CH3I) and other particles (CsI, Cs, and Te), was incorporated into WSPEEDI-II to improve the surface deposition calculations. The fallout to the ocean surface calculated by WSPEEDI-II was used as input data for the SEA-GEARN-FDM calculations. Reverse and inverse source-term estimation methods based on coupling the simulations from both models was adopted using air dose rates and concentrations, and sea surface concentrations. The results revealed that the major releases of radionuclides due to FNPS1 accident occurred in the following periods during March 2011: the afternoon of 12 March due to the wet venting and hydrogen explosion at Unit 1, the morning of 13 March after the venting event at Unit 3, midnight of 14 March when the SRV (Safely Relief Valve) at Unit 2 was opened three times, the morning and night of 15 March, and the morning of 16 March. According to the simulation results, the highest radioactive contamination areas around FNPS1 were created from 15 to 16 March by complicated interactions among rainfall, plume movements, and the temporal variation of release rates associated with reactor pressure changes in Units 2 and 3. The modified WSPEEDI-II simulation using the new source term reproduced local and regional patterns of cumulative surface deposition of total 131I and 137Cs and air dose rate obtained by airborne surveys. The new source term was also tested using three atmospheric dispersion models (MLDP0, HYSPLIT, and NAME) for regional and global calculations and showed good agreement between calculated and observed air concentration and surface deposition of 137Cs in East Japan. Moreover, HYSPLIT model using the new source term also reproduced the plume arrivals at several countries abroad showing a good correlation with measured air concentration data. A large part of deposition pattern of total 131I and 137Cs in East Japan was explained by in-cloud particulate scavenging. However, for the regional scale contaminated areas, there were large uncertainties due to the overestimation of rainfall amounts and the underestimation of fogwater and drizzle depositions. The computations showed that approximately 27% of 137Cs discharged from FNPS1 deposited to the land in East Japan, mostly in forest areas.

Financial Analysis of Experimental Releases Conducted at Glen Canyon Dam during Water Year 2015

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graziano, D. J.; Poch, L. A.; Veselka, T. D.

This report examines the financial implications of experimental flows conducted at the Glen Canyon Dam (GCD) in water year (WY) 2015. It is the seventh report in a series examining the financial implications of experimental flows conducted since the Record of Decision (ROD) was adopted in February 1997 (Reclamation 1996). A report released in January 2011 examined WYs 1997 to 2005 (Veselka et al. 2011); a report released in August 2011 examined WYs 2006 to 2010 (Poch et al. 2011); a report released June 2012 examined WY 2011 (Poch et al. 2012); a report released April 2013 examined WY 2012more » (Poch et al. 2013); a report released June 2014 examined WY 2013 (Graziano et al. 2014); and a report released September 2015 examined WY 2014 (Graziano et al. 2015). An experimental release may have either a positive or negative impact on the financial value of energy production. Only one experimental release was conducted at GCD in WY 2015; specifically, a high flow experimental (HFE) release conducted in November 2014. For this experimental release, financial costs of approximately $2.1 million were incurred because the HFE required sustained water releases that exceeded the powerplant’s maximum flow rate. In addition, during the month of the experiment, operators were not allowed to shape GCD power production to either follow firm power customer loads or to respond to market prices. This study identifies the main factors that contribute to HFE costs and examines the interdependencies among these factors. It applies an integrated set of tools to estimate financial impacts by simulating the GCD operations under two scenarios: (1) a baseline scenario that mimics both HFE operations during the experiment and during the rest of the year when it complies with the 1996 ROD operating criteria, and (2) a “without experiments” scenario that is identical to the baseline except it assumes that the HFE did not occur. The Generation and Transmission Maximization (GTMax) model was the main simulation tool used to simulate the dispatch of hydropower plants at GCD and other plants that comprise the Salt Lake City Area Integrated Projects (SLCA/IP). The research team used extensive data sets and historical information on SLCA/IP powerplant characteristics, hydrologic conditions, and Western Area Power Administration’s (WAPA’s) power purchase prices in the modeling process. In addition to estimating the financial impact of the HFE, the team used the GTMax model to gain insights into the interplay among ROD operating criteria, exceptions that were made to criteria to accommodate the experimental releases, and WAPA operating practices.« less

Effects of multiple founder populations on spatial genetic structure of reintroduced American martens.

PubMed

Williams, Bronwyn W; Scribner, Kim T

2010-01-01

Reintroductions and translocations are increasingly used to repatriate or increase probabilities of persistence for animal and plant species. Genetic and demographic characteristics of founding individuals and suitability of habitat at release sites are commonly believed to affect the success of these conservation programs. Genetic divergence among multiple source populations of American martens (Martes americana) and well documented introduction histories permitted analyses of post-introduction dispersion from release sites and development of genetic clusters in the Upper Peninsula (UP) of Michigan <50 years following release. Location and size of spatial genetic clusters and measures of individual-based autocorrelation were inferred using 11 microsatellite loci. We identified three genetic clusters in geographic proximity to original release locations. Estimated distances of effective gene flow based on spatial autocorrelation varied greatly among genetic clusters (30-90 km). Spatial contiguity of genetic clusters has been largely maintained with evidence for admixture primarily in localized regions, suggesting recent contact or locally retarded rates of gene flow. Data provide guidance for future studies of the effects of permeabilities of different land-cover and land-use features to dispersal and of other biotic and environmental factors that may contribute to the colonization process and development of spatial genetic associations.

Release from or through a wax matrix system. I. Basic release properties of the wax matrix system.

PubMed

Yonezawa, Y; Ishida, S; Sunada, H

2001-11-01

Release properties from a wax matrix tablet was examined. To obtain basic release properties, the wax matrix tablet was prepared from a physical mixture of drug and wax powder (hydrogenated caster oil) at a fixed mixing ratio. Properties of release from the single flat-faced surface or curved side surface of the wax matrix tablet were examined. The applicability of the square-root time law and of Higuchi equations was confirmed. The release rate constant obtained as g/min(1/2) changed with the release direction. However, the release rate constant obtained as g/cm2 x min(1/2) was almost the same. Hence it was suggested that the release property was almost the same and the wax matrix structure was uniform independent of release surface or direction at a fixed mixing ratio. However, these equations could not explain the entire release process. The applicability of a semilogarithmic equation was not as good compared with the square-root time law or Higuchi equation. However, it was revealed that the semilogarithmic equation was available to simulate the entire release process, even though the fit was somewhat poor. Hence it was suggested that the semilogarithmic equation was sufficient to describe the release process. The release rate constant was varied with release direction. However, these release rate constants were expressed by a function of the effective surface area and initial amount, independent of the release direction.

Reconviction and revocation rates in Flanders after medium security treatment.

PubMed

Jeandarme, Inge; Habets, Petra; Oei, T I; Bogaerts, Stefan

2016-01-01

To examine the criminal outcome of Flemish forensic psychiatric patients ('internees') after medium security treatment. Also, the effect of conditional release on recidivism of two subgroups (internees under conditional release and internees who received unconditional release) was examined. Reconviction rates and revocation rates were collected for all participants. Kaplan-Meier survival analyses were used to investigate recidivism rates while controlling for time at risk. During the 10-year period, 502 offenders were discharged from medium security treatment. Over a follow-up period averaging 3.6years, 7.4% of discharged patients were reconvicted or received a new 'not guilty by reason of insanity' (NGRI) verdict for a violent offence. One-quarter of the population had their conditional release revoked. Part of the study population was granted unconditional release. Reconviction rates were higher after unconditional release in comparison to conditional release. The results of this study suggest that the court supervision of NGRI patients in Flanders is effective in protecting the community from further offending. Copyright © 2016 Elsevier Ltd. All rights reserved.

Atmospheric Sulfur Hexafluoride: Sources, Sinks and Greenhouse Warming

NASA Technical Reports Server (NTRS)

Sze, Nien Dak; Wang, Wei-Chyung; Shia, George; Goldman, Aaron; Murcray, Frank J.; Murcray, David G.; Rinsland, Curtis P.

1993-01-01

Model calculations using estimated reaction rates of sulfur hexafluoride (SF6) with OH and 0('D) indicate that the atmospheric lifetime due to these processes may be very long (25,000 years). An upper limit for the UV cross section would suggest a photolysis lifetime much longer than 1000 years. The possibility of other removal mechanisms are discussed. The estimated lifetimes are consistent with other estimated values based on recent laboratory measurements. There appears to be no known natural source of SF6. An estimate of the current production rate of SF6 is about 5 kt/yr. Based on historical emission rates, we calculated a present-day atmospheric concentrations for SF6 of about 2.5 parts per trillion by volume (pptv) and compared the results with available atmospheric measurements. It is difficult to estimate the atmospheric lifetime of SF6 based on mass balance of the emission rate and observed abundance. There are large uncertainties concerning what portion of the SF6 is released to the atmosphere. Even if the emission rate were precisely known, it would be difficult to distinguish among lifetimes longer than 100 years since the current abundance of SF6 is due to emission in the past three decades. More information on the measured trends over the past decade and observed vertical and latitudinal distributions of SF6 in the lower stratosphere will help to narrow the uncertainty in the lifetime. Based on laboratory-measured IR absorption cross section for SF6, we showed that SF6 is about 3 times more effective as a greenhouse gas compared to CFC 11 on a per molecule basis. However, its effect on atmospheric warming will be minimal because of its very small concentration. We estimated the future concentration of SF6 at 2010 to be 8 and 10 pptv based on two projected emission scenarios. The corresponding equilibrium warming of 0.0035 C and 0.0043 C is to be compared with the estimated warming due to CO2 increase of about 0.8 C in the same period.

Development of extended release dosage forms using non-uniform drug distribution techniques.

PubMed

Huang, Kuo-Kuang; Wang, Da-Peng; Meng, Chung-Ling

2002-05-01

Development of an extended release oral dosage form for nifedipine using the non-uniform drug distribution matrix method was conducted. The process conducted in a fluid bed processing unit was optimized by controlling the concentration gradient of nifedipine in the coating solution and the spray rate applied to the non-pareil beads. The concentration of nifedipine in the coating was controlled by instantaneous dilutions of coating solution with polymer dispersion transported from another reservoir into the coating solution at a controlled rate. The USP dissolution method equipped with paddles at 100 rpm in 0.1 N hydrochloric acid solution maintained at 37 degrees C was used for the evaluation of release rate characteristics. Results indicated that (1) an increase in the ethyl cellulose content in the coated beads decreased the nifedipine release rate, (2) incorporation of water-soluble sucrose into the formulation increased the release rate of nifedipine, and (3) adjustment of the spray coating solution and the transport rate of polymer dispersion could achieve a dosage form with a zero-order release rate. Since zero-order release rate and constant plasma concentration were achieved in this study using the non-uniform drug distribution technique, further studies to determine in vivo/in vitro correlation with various non-uniform drug distribution dosage forms will be conducted.

Interaction between fed gastric media (Ensure Plus®) and different hypromellose based caffeine controlled release tablets: comparison and mechanistic study of caffeine release in fed and fasted media versus water using the USP dissolution apparatus 3.

PubMed

Franek, Frans; Holm, Per; Larsen, Frank; Steffansen, Bente

2014-01-30

The aim of the study was to investigate caffeine release in fed and fasted state media from three controlled release matrix tablets containing different HPMC viscosity grades. The biorelevant in vitro dissolution methods utilize the USP 3 dissolution apparatus and biorelevant media to simulate fed and fasted gastro-intestinal dissolution conditions. The effect of tablet reciprocation rate (dip speed) in dissolution media (10 and 15 dips per minute) and media (water, fed and fasted) on caffeine release rate from - and erosion rate of - 100, 4000 and 15,000 mPa s HPMC viscosity tablets was investigated using factorial designed experiments. Furthermore, the mechanism of release in Ensure Plus(®), a nutrition drink similar in composition to the FDA standard meal, was investigated by studying tablet swelling using texture analysis. Altering dip speed has negligible effect on release and erosion rates. Using fasted media instead of water slightly decreases caffeine release from 100 and 4000 mPa s HPMC viscosity tablets as well as erosion rates, while 15,000 mPa s tablets remain unaffected. Fed compared to fasted media decreases caffeine release rate, and the food effect is greater for the 100 mPa s viscosity tablets compared to the 4000 and 15,000 mPa s viscosity tablets. The investigation using texture analysis indicates that Ensure Plus(®) becomes rate-limiting for caffeine release from HPMC tablets by forming a hydrophobic barrier around the tablets. The barrier decreases tablet water permeation, which decreases erosion rate in 100 mPa s viscosity tablets, swelling in 15,000 mPa s viscosity tablets and caffeine release from both tablets. This observed interaction between Ensure Plus(®) and the HPMC tablets may translate into decreased drug release rate in the fed stomach, which may decrease the amount of drug available for absorption in the small intestine and thus reduce systemic drug exposure and maximum plasma concentration. Copyright © 2013 Elsevier B.V. All rights reserved.

Influence of space use on fitness and the reintroduction success of the Laysan teal

USGS Publications Warehouse

Reynolds, M.H.; Hatfield, J.S.; Laniawe, L.P.; Vekasy, M.S.; Klavitter, J.L.; Berkowitz, P.; Crampton, L.H.; Walters, J.R.

2012-01-01

Translocation is an important tool for wildlife conservation and biodiversity restoration, but an inefficient one because of the unpredictability of success. Predictors of success such as habitat quality of the release site and number of individuals released have been identified, but the dynamics of successful translocations remain poorly understood. In particular, little is known about the relationship of individual post-release movements to population establishment. In 2004, Laysan teal Anas laysanensis were reintroduced by translocating 20 wild birds from Laysan Island to Midway Atoll. Twenty-two additional wild founders were brought the next year. We monitored the survival, reproductive success and movements of the 42 translocated individuals and their offspring for 4 years. Additionally, we monitored population size from 2004 to 2010. Unlike most translocations, we did not observe elevated post-release mortality despite flight-feather trimming to prevent immediate dispersal off-island: first year survival was > 90% and survival rates until 2009 were 0.65±0.08 for founding adults. Laysan teal flew between the two main islands of Midway Atoll, and offspring had significantly larger maximum movement distances than founders. We monitored 84 nests and observed a significant, negative relationship of home range size to productivity for founding females. Flightless founders did not show fidelity to their release sites, but had strong fidelity to annual home ranges after attaining flight. Although we observed a component Allee effect on mate-finding, this did not translate into a demographic Allee effect, and generally, the high fitness of founders contributed substantially to successful population establishment. Laysan teal abundance increased linearly until 2009, but showed evidence of population regulation afterwards. The population estimate was 473 (95% confidence interval 439–508) in 2010. On the much larger main Hawaiian Islands, we expect greater post-release movement, a stronger component Allee effect, lower survival and lower reproductive rates because of predation to preclude successful reintroductions of this species to sites without predator management.

SO2 flux and the thermal power of volcanic eruptions

NASA Astrophysics Data System (ADS)

Henley, Richard W.; Hughes, Graham O.

2016-09-01

A description of the dynamics, chemistry and energetics governing a volcanic system can be greatly simplified if the expansion of magmatic gas can be assumed to be adiabatic as it rises towards the surface. The conditions under which this assumption is valid are clarified by analysis of the transfer of thermal energy into the low conductivity wallrocks traversed by fractures and vents from a gas phase expanding over a range of mass flux rates. Adiabatic behavior is predicted to be approached typically within a month after perturbations in the release of source gas have stabilized, this timescale being dependent upon only the characteristic length scale on which the host rock is fractured and the thermal diffusivity of the rock. This analysis then enables the thermal energy transport due to gas release from volcanoes to be evaluated using observations of SO2 flux with reference values for the H2O:SO2 ratio of volcanic gas mixtures discharging through high temperature fumaroles in arc and mantle-related volcanic systems. Thermal power estimates for gas discharge are 101.8 to 104.1 MWH during quiescent, continuous degassing of arc volcanoes and 103.7 to 107.3 MWH for their eruptive stages, the higher value being the Plinean Pinatubo eruption in 1991. Fewer data are available for quiescent stage mantle-related volcanoes (Kilauea 102.1 MWH) but for eruptive events power estimates range from 102.8 MWH to 105.5 MWH. These estimates of thermal power and mass of gas discharges are commensurate with power estimates based on the total mass of gas ejected during eruptions. The sustained discharge of volcanic gas during quiescent and short-lived eruptive stages can be related to the hydrodynamic structure of volcanic systems with large scale gaseous mass transfer from deep in the crust coupled with episodes of high level intrusive activity and gas release.

Climate-driven vital rates do not always mean climate-driven population.

PubMed

Tavecchia, Giacomo; Tenan, Simone; Pradel, Roger; Igual, José-Manuel; Genovart, Meritxell; Oro, Daniel

2016-12-01

Current climatic changes have increased the need to forecast population responses to climate variability. A common approach to address this question is through models that project current population state using the functional relationship between demographic rates and climatic variables. We argue that this approach can lead to erroneous conclusions when interpopulation dispersal is not considered. We found that immigration can release the population from climate-driven trajectories even when local vital rates are climate dependent. We illustrated this using individual-based data on a trans-equatorial migratory seabird, the Scopoli's shearwater Calonectris diomedea, in which the variation of vital rates has been associated with large-scale climatic indices. We compared the population annual growth rate λ i , estimated using local climate-driven parameters with ρ i , a population growth rate directly estimated from individual information and that accounts for immigration. While λ i varied as a function of climatic variables, reflecting the climate-dependent parameters, ρ i did not, indicating that dispersal decouples the relationship between population growth and climate variables from that between climatic variables and vital rates. Our results suggest caution when assessing demographic effects of climatic variability especially in open populations for very mobile organisms such as fish, marine mammals, bats, or birds. When a population model cannot be validated or it is not detailed enough, ignoring immigration might lead to misleading climate-driven projections. © 2016 John Wiley & Sons Ltd.

Rate and Equilibrium Constants for an Enzyme Conformational Change during Catalysis by Orotidine 5'-Monophosphate Decarboxylase.

PubMed

Goryanova, Bogdana; Goldman, Lawrence M; Ming, Shonoi; Amyes, Tina L; Gerlt, John A; Richard, John P

2015-07-28

The caged complex between orotidine 5'-monophosphate decarboxylase (ScOMPDC) and 5-fluoroorotidine 5'-monophosphate (FOMP) undergoes decarboxylation ∼300 times faster than the caged complex between ScOMPDC and the physiological substrate, orotidine 5'-monophosphate (OMP). Consequently, the enzyme conformational changes required to lock FOMP at a protein cage and release product 5-fluorouridine 5'-monophosphate (FUMP) are kinetically significant steps. The caged form of ScOMPDC is stabilized by interactions between the side chains from Gln215, Tyr217, and Arg235 and the substrate phosphodianion. The control of these interactions over the barrier to the binding of FOMP and the release of FUMP was probed by determining the effect of all combinations of single, double, and triple Q215A, Y217F, and R235A mutations on kcat/Km and kcat for turnover of FOMP by wild-type ScOMPDC; its values are limited by the rates of substrate binding and product release, respectively. The Q215A and Y217F mutations each result in an increase in kcat and a decrease in kcat/Km, due to a weakening of the protein-phosphodianion interactions that favor fast product release and slow substrate binding. The Q215A/R235A mutation causes a large decrease in the kinetic parameters for ScOMPDC-catalyzed decarboxylation of OMP, which are limited by the rate of the decarboxylation step, but much smaller decreases in the kinetic parameters for ScOMPDC-catalyzed decarboxylation of FOMP, which are limited by the rate of enzyme conformational changes. By contrast, the Y217A mutation results in large decreases in kcat/Km for ScOMPDC-catalyzed decarboxylation of both OMP and FOMP, because of the comparable effects of this mutation on rate-determining decarboxylation of enzyme-bound OMP and on the rate-determining enzyme conformational change for decarboxylation of FOMP. We propose that kcat = 8.2 s(-1) for decarboxylation of FOMP by the Y217A mutant is equal to the rate constant for cage formation from the complex between FOMP and the open enzyme, that the tyrosyl phenol group stabilizes the closed form of ScOMPDC by hydrogen bonding to the substrate phosphodianion, and that the phenyl group of Y217 and F217 facilitates formation of the transition state for the rate-limiting conformational change. An analysis of kinetic data for mutant enzyme-catalyzed decarboxylation of OMP and FOMP provides estimates for the rate and equilibrium constants for the conformational change that traps FOMP at the enzyme active site.

Residual thermal and moisture influences on the strain energy release rate analysis of edge delamination

NASA Technical Reports Server (NTRS)

Obrien, T. K.; Raju, I. S.; Garber, D. P.

1985-01-01

A laminated plate theory analysis is developed to calculate the strain energy release rate associated with edge delamination growth in a composite laminate. The analysis includes the contribution of residual thermal and moisture stresses to the strain energy released. The strain energy release rate, G, increased when residual thermal effects were combined with applied mechanical strains, but then decreased when increasing moisture content was included. A quasi-three-dimensional finite element analysis indicated identical trends and demonstrated these same trends for the individual strain energy release rate components, G sub I and G sub II, associated with interlaminar tension and shear. An experimental study indicated that for T300/5208 graphite-epoxy composites, the inclusion of residual thermal and moisture stresses did not significantly alter the calculation of interlaminar fracture toughness from strain energy release rate analysis of edge delamination data taken at room temperature, ambient conditions.

Quantification of Energy Release in Composite Structures

NASA Technical Reports Server (NTRS)

Minnetyan, Levon

2003-01-01

Energy release rate is usually suggested as a quantifier for assessing structural damage tolerance. Computational prediction of energy release rate is based on composite mechanics with micro-stress level damage assessment, finite element structural analysis and damage progression tracking modules. This report examines several issues associated with energy release rates in composite structures as follows: Chapter I demonstrates computational simulation of an adhesively bonded composite joint and validates the computed energy release rates by comparison with acoustic emission signals in the overall sense. Chapter II investigates the effect of crack plane orientation with respect to fiber direction on the energy release rates. Chapter III quantifies the effects of contiguous constraint plies on the residual stiffness of a 90 ply subjected to transverse tensile fractures. Chapter IV compares ICAN and ICAN/JAVA solutions of composites. Chapter V examines the effects of composite structural geometry and boundary conditions on damage progression characteristics.

Quantification of Energy Release in Composite Structures

NASA Technical Reports Server (NTRS)

Minnetyan, Levon; Chamis, Christos C. (Technical Monitor)

2003-01-01

Energy release rate is usually suggested as a quantifier for assessing structural damage tolerance. Computational prediction of energy release rate is based on composite mechanics with micro-stress level damage assessment, finite element structural analysis and damage progression tracking modules. This report examines several issues associated with energy release rates in composite structures as follows: Chapter I demonstrates computational simulation of an adhesively bonded composite joint and validates the computed energy release rates by comparison with acoustic emission signals in the overall sense. Chapter II investigates the effect of crack plane orientation with respect to fiber direction on the energy release rates. Chapter III quantifies the effects of contiguous constraint plies on the residual stiffness of a 90 deg ply subjected to transverse tensile fractures. Chapter IV compares ICAN and ICAN/JAVA solutions of composites. Chapter V examines the effects of composite structural geometry and boundary conditions on damage progression characteristics.

RADIOLYTIC GAS PRODUCTION RATES OF POLYMERS EXPOSED TO TRITIUM GAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, E.

Data from previous reports on studies of polymers exposed to tritium gas is further analyzed to estimate rates of radiolytic gas production. Also, graphs of gas release during tritium exposure from ultrahigh molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, a trade name is Teflon®), and Vespel® polyimide are re-plotted as moles of gas as a function of time, which is consistent with a later study of tritium effects on various formulations of the elastomer ethylene-propylene-diene monomer (EPDM). These gas production rate estimates may be useful while considering using these polymers in tritium processing systems. These rates are valid at least formore » the longest exposure times for each material, two years for UHMW-PE, PTFE, and Vespel®, and fourteen months for filled and unfilled EPDM. Note that the production “rate” for Vespel® is a quantity of H{sub 2} produced during a single exposure to tritium, independent of length of time. The larger production rate per unit mass for unfilled EPDM results from the lack of filler- the carbon black in filled EPDM does not produce H{sub 2} or HT. This is one aspect of how inert fillers reduce the effects of ionizing radiation on polymers.« less

The completeness-corrected rate of stellar encounters with the Sun from the first Gaia data release

NASA Astrophysics Data System (ADS)

Bailer-Jones, C. A. L.

2018-01-01

I report on close encounters of stars to the Sun found in the first Gaia data release (GDR1). Combining Gaia astrometry with radial velocities of around 320 000 stars drawn from various catalogues, I integrate orbits in a Galactic potential to identify those stars which pass within a few parsecs. Such encounters could influence the solar system, for example through gravitational perturbations of the Oort cloud. 16 stars are found to come within 2 pc (although a few of these have dubious data). This is fewer than were found in a similar study based on HIPPARCOS data, even though the present study has many more candidates. This is partly because I reject stars with large radial velocity uncertainties (>10 km s-1), and partly because of missing stars in GDR1 (especially at the bright end). The closest encounter found is Gl 710, a K dwarf long-known to come close to the Sun in about 1.3 Myr. The Gaia astrometry predict a much closer passage than pre-Gaia estimates, however: just 16 000 AU (90% confidence interval: 10 000-21 000 AU), which will bring this star well within the Oort cloud. Using a simple model for the spatial, velocity, and luminosity distributions of stars, together with an approximation of the observational selection function, I model the incompleteness of this Gaia-based search as a function of the time and distance of closest approach. Applying this to a subset of the observed encounters (excluding duplicates and stars with implausibly large velocities), I estimate the rate of stellar encounters within 5 pc averaged over the past and future 5 Myr to be 545 ± 59 Myr-1. Assuming a quadratic scaling of the rate within some encounter distance (which my model predicts), this corresponds to 87 ± 9 Myr-1 within 2 pc. A more accurate analysis and assessment will be possible with future Gaia data releases. Full Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A8

The Roles of Parasitoid Foraging for Hosts, Food and Mates in the Augmentative Control of Tephritidae.

PubMed

Sivinski, John; Aluja, Martin

2012-07-20

Ultimately, the success of augmentative fruit fly biological control depends upon the survival, dispersal, attack rate and multi-generational persistence of mass-reared parasitoids in the field. Foraging for hosts, food and mates is fundamental to the above and, at an operational level, the choice of the parasitoid best suited to control a particular tephritid in a certain environment, release rate estimates and subsequent monitoring of effectiveness. In the following we review landscape-level and microhabitat foraging preferences, host/fruit ranges, orientation through environmental cues, host vulnerabilities/ovipositor structures, and inter and intraspecific competition. We also consider tephritid parasitoid mating systems and sexual signals, and suggest the directions of future research.

Controlling the Release of Indomethacin from Glass Solutions Layered with a Rate Controlling Membrane Using Fluid-Bed Processing. Part 2: The Influence of Formulation Parameters on Drug Release.

PubMed

Dereymaker, Aswin; Pelgrims, Jirka; Engelen, Frederik; Adriaensens, Peter; Van den Mooter, Guy

2017-04-03

This study aimed to investigate the pharmaceutical performance of an indomethacin-polyvinylpyrrolidone (PVP) glass solution applied using fluid bed processing as a layer on inert sucrose spheres and subsequently top-coated with a release rate controlling membrane consisting of either ethyl cellulose or Eudragit RL. The implications of the addition of a pore former (PVP) and the coating medium (ethanol or water) on the diffusion and release behavior were also considered. In addition, the role of a charge interaction between drug and controlled release polymer on the release was investigated. Diffusion experiments pointed to the influence of pore former concentration, rate controlling polymer type, and coating solvent on the permeability of the controlled release membranes. This can be translated to drug release tests, which show the potential of diffusion tests as a preliminary screening test and that diffusion is the main factor influencing release. Drug release tests also showed the effect of coating layer thickness. A charge interaction between INDO and ERL was demonstrated, but this had no negative effect on drug release. The higher diffusion and release observed in ERL-based rate controlling membranes was explained by a higher hydrophilicity, compared to EC.

Monitoring for the management of disease risk in animal translocation programmes

USGS Publications Warehouse

Nichols, James D.; Hollmen, Tuula E.; Grand, James B.

2017-01-01

Monitoring is best viewed as a component of some larger programme focused on science or conservation. The value of monitoring is determined by the extent to which it informs the parent process. Animal translocation programmes are typically designed to augment or establish viable animal populations without changing the local community in any detrimental way. Such programmes seek to minimize disease risk to local wild animals, to translocated animals, and in some cases to humans. Disease monitoring can inform translocation decisions by (1) providing information for state-dependent decisions, (2) assessing progress towards programme objectives, and (3) permitting learning in order to make better decisions in the future. Here we discuss specific decisions that can be informed by both pre-release and post-release disease monitoring programmes. We specify state variables and vital rates needed to inform these decisions. We then discuss monitoring data and analytic methods that can be used to estimate these state variables and vital rates. Our discussion is necessarily general, but hopefully provides a basis for tailoring disease monitoring approaches to specific translocation programmes.

Star Formation & the Star Formation History of the Universe: Exploring the X-ray and the Multi-wavelength Point of Views

NASA Astrophysics Data System (ADS)

Burgarella, Denis; Ciesla, Laure; Boquien, Mederic; Buat, Veronique; Roehlly, Yannick

2015-09-01

The star formation rate density traces the formation of stars in the universe. To estimate the star formation rate of galaxies, we can use a wide range of star formation tracers: continuum measurements in most wavelength domains, lines, supernovae and GRBs... All of them have pros and cons. Most of the monochromatic tracers are hampered but the effects of dust. But, before being able to estimate the star formation rate, we first need to obtain a safe estimate to the dust attenuation. The advantage of the X-ray wavelength range is that we can consider it as free from the effect of dust. In this talk, we will estimate how many galaxies we could detect with ATHENA to obtain the star formation density. For this, I will use my recent Herschel paper where the total (UV + IR) star formation rate density was evaluated up to z ~ 4 and provide quantitative figures for what ATHENA will detect as a function of the redshift and the luminosity. ATHENA will need predictions that are in agreement with what we observe in the other wavelength ranges. I will present the code CIGALE (http://cigale.lam.fr). The new and public version of CIGALE (released in April 2015) allows to model the emission of galaxies from the far-ultraviolet to the radio and it can make prediction in any of these wavelength ranges. I will show how galaxy star formation rates can be estimated in a way that combines all the advantages of monochromatic tracers but not the caveats. It should be stressed that we can model the emission of AGNs in the FUV-to-FIR range using several models. Finally, I will explain why we seriously consider to extend CIGALE to the x-ray range to predict the X-ray emission of galaxies including any AGN.

Synthesizing the Use of Carbon Isotope (14C and 13C) Approaches to Understand Rates and Pathways for Permafrost C Mobilization and Mineralization

NASA Astrophysics Data System (ADS)

Estop-Aragones, C.; Olefeldt, D.; Schuur, E.

2015-12-01

To better understand the permafrost carbon (C) feedback it is important to synthesize our current knowledge, and knowledge gaps, of how permafrost thaw can cause in situ mineralization or downstream mobilization of aged soil organic carbon (SOC) and the rate of this release. This potential loss of old SOC may occur via gaseous flux of CO2 and CH4 exchanged between soil and the atmosphere and via waterborne flux as DOC, POC (and their subsequent decomposition and release to the atmosphere). Carbon isotope (14C and 13C) approaches have been used to estimate both rates and pathways for permafrost C mobilization and mineralization. Radiocarbon (14C) has been used to estimate the contribution of aged C to overall respiration or waterborne C export. We aim to contrast results from radiocarbon studies, in order to assess differences between ecosystems (contrasting wet and dry ecosystems), thaw histories (active layer deepening or thermokarst landforms), greenhouse gas considered (CO2 and CH4) and seasons. We propose to also contrast methodologies used for assessing the contribution of aged C to overall C balance, and include studies using 13C data. Biological fractionation of 13C during both uptake and decomposition has been taken advantage of both in order to aid the interpretation of 14C data and on its own to assess sources and mineralization pathways. For example, 13C data has been used to differentiate between CH4 production pathways, and the relative contribution of anaerobic CO2 production to overall respiration. Overall, carbon isotope research is proving highly valuable for our understanding of permafrost C dynamics following thaw, and there is a current need to synthesize the available literature.

The energy cost of triglyceride-fatty acid recycling in nonobese subjects after an overnight fast and four days of starvation.

PubMed

Elia, M; Zed, C; Neale, G; Livesey, G

1987-03-01

The basal blood glycerol concentration was determined and the rate of glycerol turnover was assessed by a nonradioactive infusion technique in six healthy nonobese adults after an overnight fast and again after four days of total starvation. Simultaneously, estimates of total energy expenditure and net fat oxidation were made from measurements of oxygen consumption, carbon dioxide production, and urinary nitrogen excretion. The data were combined to provide quantitative estimates of the activity of the triglyceride/fatty acid cycle. The basal concentration of glycerol in venous blood rose from a mean value of 54 +/- 8 mumol/L (SEM) before starvation to 154 +/- 5 mumol/L on day 4 of starvation. Glycerol turnover rates correlated well with the basal blood glycerol concentration (r = .95) and increased from a mean value of 115 +/- 17 mumol/min before starvation (equivalent to mobilization of about 3.95 kJ triglyceride/min) to 304 +/- 20 mumol/min (equivalent to mobilization of about 18.41 kJ/min). The estimated rate of net fat oxidation was 3.00 +/- 0.47 kJ/min before starvation and 4.00 +/- 0.14 kJ/min on day +4 of starvation. The rate of triglyceride energy recycling or rate of deposition of triglyceride energy into fat stores was calculated from the difference in the rate of fat energy mobilization and the rate of energy released during net fat oxidation. The values were found to be 0.94 +/- 0.26 kJ/min before starvation and 6.29 +/- 0.54 kJ/min on day +4 of starvation.(ABSTRACT TRUNCATED AT 250 WORDS)

77 FR 47918 - Information Collection Activities (Released Rates)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-10

... decision in Released Rates of Motor Common Carriers of Household Goods, Docket No. RR 999 (Amendment No. 5... loss or damage that occurs during interstate household-good moves. See Safe, Accountable, Flexible... elects anything other than full-value protection. See Released Rates of Motor Common Carriers of...

Paying the piper: the cost of Ca2+ pumping during the mating call of toadfish

PubMed Central

Harwood, Claire L; Young, Iain S; Tikunov, Boris A; Hollingworth, Stephen; Baylor, Stephen M; Rome, Lawrence C

2011-01-01

Abstract Superfast fibres of toadfish swimbladder muscle generate a series of superfast Ca2+ transients, a necessity for high-frequency calling. How is this accomplished with a relatively low rate of Ca2+ pumping by the sarcoplasmic reticulum (SR)? We hypothesized that there may not be complete Ca2+ saturation and desaturation of the troponin Ca2+ regulatory sites with each twitch during calling. To test this, we determined the number of regulatory sites by measuring the concentration of troponin C (TNC) molecules, 33.8 μmol per kg wet weight. We then estimated how much SR Ca2+ is released per twitch by measuring the recovery oxygen consumption in the presence of a crossbridge blocker, N-benzyl-p-toluene sulphonamide (BTS). The results agreed closely with SR release estimates obtained with a kinetic model used to analyse Ca2+ transient measurements. We found that 235 μmol of Ca2+ per kg muscle is released with the first twitch of an 80 Hz stimulus (15oC). Release per twitch declines dramatically thereafter such that by the 10th twitch release is only 48 μmol kg−1 (well below the concentration of TNC Ca2+ regulatory sites, 67.6 μmol kg−1). The ATP usage per twitch by the myosin crossbridges remains essentially constant at ∼25 μmol kg−1 throughout the stimulus period. Hence, for the first twitch, ∼80% of the energy goes into pumping Ca2+ (which uses 1 ATP per 2 Ca2+ ions pumped), but by the 10th and subsequent twitches the proportion is ∼50%. Even though by the 10th stimulus the Ca2+ release per twitch has dropped 5-fold, the Ca2+ remaining in the SR has declined by only ∼18%; hence dwindling SR Ca2+ content is not responsible for the drop. Rather, inactivation of the Ca2+ release channel by myoplasmic Ca2+ likely explains this reduction. If inactivation did not occur, the SR would run out of Ca2+ well before the end of even a 40-twitch call. Hence, inactivation of the Ca2+ release channel plays a critical role in swimbladder muscle during normal in vivo function. PMID:21946852

Passive Diffusion as a Mechanism Underlying Ribbon Synapse Vesicle Release and Resupply

PubMed Central

Graydon, Cole W.; Zhang, Jun; Oesch, Nicholas W.; Sousa, Alioscka A.; Leapman, Richard D.

2014-01-01

Synaptic ribbons are presynaptic protein structures found at many synapses that convey graded, “analog” sensory signals in the visual, auditory, and vestibular pathways. Ribbons, typically anchored to the presynaptic membrane and surrounded by tethered synaptic vesicles, are thought to regulate or facilitate vesicle delivery to the presynaptic membrane. No direct evidence exists, however, to indicate how vesicles interact with the ribbon or, once attached, move along the ribbon's surface to reach the presynaptic release sites at its base. To address these questions, we have created, validated, and tested a passive vesicle diffusion model of retinal rod bipolar cell ribbon synapses. We used axial (bright-field) electron tomography in the scanning transmission electron microscopy to obtain 3D structures of rat rod bipolar cell terminals in 1-μm-thick sections of retinal tissue at an isotropic spatial resolution of ∼3 nm. The resulting structures were then incorporated with previously published estimates of vesicle diffusion dynamics into numerical simulations that accurately reproduced electrophysiologically measured vesicle release/replenishment rates and vesicle pool sizes. The simulations suggest that, under physiologically realistic conditions, diffusion of vesicles crowded on the ribbon surface gives rise to a flow field that enhances delivery of vesicles to the presynaptic membrane without requiring an active transport mechanism. Numerical simulations of ribbon–vesicle interactions predict that transient binding and unbinding of multiple tethers to each synaptic vesicle may achieve sufficiently tight association of vesicles to the ribbon while permitting the fast diffusion along the ribbon that is required to sustain high release rates. PMID:24990916

Passive diffusion as a mechanism underlying ribbon synapse vesicle release and resupply.

PubMed

Graydon, Cole W; Zhang, Jun; Oesch, Nicholas W; Sousa, Alioscka A; Leapman, Richard D; Diamond, Jeffrey S

2014-07-02

Synaptic ribbons are presynaptic protein structures found at many synapses that convey graded, "analog" sensory signals in the visual, auditory, and vestibular pathways. Ribbons, typically anchored to the presynaptic membrane and surrounded by tethered synaptic vesicles, are thought to regulate or facilitate vesicle delivery to the presynaptic membrane. No direct evidence exists, however, to indicate how vesicles interact with the ribbon or, once attached, move along the ribbon's surface to reach the presynaptic release sites at its base. To address these questions, we have created, validated, and tested a passive vesicle diffusion model of retinal rod bipolar cell ribbon synapses. We used axial (bright-field) electron tomography in the scanning transmission electron microscopy to obtain 3D structures of rat rod bipolar cell terminals in 1-μm-thick sections of retinal tissue at an isotropic spatial resolution of ∼3 nm. The resulting structures were then incorporated with previously published estimates of vesicle diffusion dynamics into numerical simulations that accurately reproduced electrophysiologically measured vesicle release/replenishment rates and vesicle pool sizes. The simulations suggest that, under physiologically realistic conditions, diffusion of vesicles crowded on the ribbon surface gives rise to a flow field that enhances delivery of vesicles to the presynaptic membrane without requiring an active transport mechanism. Numerical simulations of ribbon-vesicle interactions predict that transient binding and unbinding of multiple tethers to each synaptic vesicle may achieve sufficiently tight association of vesicles to the ribbon while permitting the fast diffusion along the ribbon that is required to sustain high release rates. Copyright © 2014 the authors 0270-6474/14/348948-15$15.00/0.

Use of an exchange method to estimate the association and dissociation rate constants of cadmium complexes formed with low-molecular-weight organic acids commonly exuded by plant roots.

PubMed

Schneider, André; Nguyen, Christophe

2011-01-01

Organic acids released from plant roots can form complexes with cadmium (Cd) in the soil solution and influence metal bioavailability not only due to the nature and concentration of the complexes but also due to their lability. The lability of a complex influences its ability to buffer changes in the concentration of free ions (Cd); it depends on the association (, m mol s) and dissociation (, s) rate constants. A resin exchange method was used to estimate and (m mol s), which is the conditional estimate of depending on the calcium (Ca) concentration in solution. The constants were estimated for oxalate, citrate, and malate, three low-molecular-weight organic acids commonly exuded by plant roots and expected to strongly influence Cd uptake by plants. For all three organic acids, the and estimates were around 2.5 10 m mol s and 1.3 × 10 s, respectively. Based on the literature, these values indicate that the Cd- low-molecular-weight organic acids complexes formed between Cd and low-molecular-weight organic acids may be less labile than complexes formed with soil soluble organic matter but more labile than those formed with aminopolycarboxylic chelates. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Estimates of water and solute release from a coal waste rock dump in the Elk Valley, British Columbia, Canada.

PubMed

Villeneuve, S A; Barbour, S L; Hendry, M J; Carey, S K

2017-12-01

Long term (1999 to 2014) flow and water quality data from a rock drain located at the base of a coal waste rock dump constructed in the Elk Valley, British Columbia was used to characterize the release of three solutes (NO 3 - , Cl - and SO 4 2- ) from the dump and obtain whole dump estimates of net percolation (NP). The concentrations of dump derived solutes in the rock drain water were diluted by snowmelt waters from the adjacent natural watershed during the spring freshet and reached a maximum concentration during the winter baseflow period. Historical peak baseflow concentrations of conservative ions (NO 3 - and Cl - ) increased until 2006/07 after which they decreased. This decrease was attributed to completion of the flushing of the first pore volume of water stored within the dump. The baseflow SO 4 2- concentrations increased proportionally with NO 3 - and Cl - to 2007, but then continued to slowly increase as NO 3 - and Cl - concentrations decreased. This was attributed to ongoing production of SO 4 2- due to oxidation of sulfide minerals within the dump. Based on partitioning of the annual volume of water discharged from the rock drain to waste rock effluent (NP) and water entering the rock drain laterally from the natural watershed, the mean NP values were estimated to be 446±50mm/a (area normalized net percolation/year) for the dump and 172±71mm/a for the natural watershed. The difference was attributed to greater rates of recharge in the dump from summer precipitation compared to the natural watershed where rainfall interception and enhanced evapotranspiration will increase water losses. These estimates included water moving through subsurface pathways. However, given the limitations in quantifying these flows the estimated NP rates for both the natural watershed and the waste rock dump are considered to be low, and could be much higher (e.g. ~450mm/a and ~800mm/a). Copyright © 2017 Elsevier B.V. All rights reserved.

Potential slab avalanche release area identification from estimated winter terrain: a multi-scale, fuzzy logic approach

NASA Astrophysics Data System (ADS)

Veitinger, Jochen; Purves, Ross Stuart; Sovilla, Betty

2016-10-01

Avalanche hazard assessment requires a very precise estimation of the release area, which still depends, to a large extent, on expert judgement of avalanche specialists. Therefore, a new algorithm for automated identification of potential avalanche release areas was developed. It overcomes some of the limitations of previous tools, which are currently not often applied in hazard mitigation practice. By introducing a multi-scale roughness parameter, fine-scale topography and its attenuation under snow influence is captured. This allows the assessment of snow influence on terrain morphology and, consequently, potential release area size and location. The integration of a wind shelter index enables the user to define release area scenarios as a function of the prevailing wind direction or single storm events. A case study illustrates the practical usefulness of this approach for the definition of release area scenarios under varying snow cover and wind conditions. A validation with historical data demonstrated an improved estimation of avalanche release areas. Our method outperforms a slope-based approach, in particular for more frequent avalanches; however, the application of the algorithm as a forecasting tool remains limited, as snowpack stability is not integrated. Future research activity should therefore focus on the coupling of the algorithm with snowpack conditions.

Energy reallocation during and after periods of nutritional stress in Steller sea lions: low-quality diet reduces capacity for physiological adjustments.

PubMed

Jeanniard du Dot, Tiphaine; Rosen, David A S; Trites, Andrew W

2009-01-01

Two groups of female Steller sea lions (groups H and P) were subjected to periods of energy restriction and subsequent refeeding during winter and summer to determine changes in energy partitioning among principal physiological functions and the potential consequences to their fitness. Both sea lion groups consumed high-quality fish (herring) before and after the energy restrictions. During restrictions, group H was fed a lower quantity of herring and group P a caloric equivalent of low-quality fish (pollock). Quantitative estimates of maintenance and production energies and qualitative estimates of thermoregulation, activity, and basal metabolic rate were measured. During summer, all animals compensated for the imposed energy deficit by releasing stored energy (production energy). Group H also optimized the energy allocation to seasonal conditions by increasing activity during summer, when fish are naturally abundant (foraging effort), and by decreasing thermoregulation capacity when waters are warmer. During winter, both groups decreased the energy allocated to overall maintenance functions (basal metabolic rate, thermoregulation, and activity together) in addition to releasing stored energy, but they preserved thermoregulatory capacity. Group H also decreased activity levels in winter, when foraging in the wild is less efficient, unlike group P. Overall, sea lions fed pollock did not change energy allocation to suit environmental conditions as readily as those fed herring. This implies that a low energy-density diet may further reduce fitness of animals in the wild during periods of nutritional stress.

Latent Heating from TRMM Satellite Measurements

NASA Technical Reports Server (NTRS)

Tao, Wei-Kuo; Smith, E. A.; Adler, R.; Haddad, Z.; Hou, A.; Iguchi, T.; Kakar, R.; Krishnamurti, T.; Kummerow, C.; Lang, S.

2004-01-01

Rainfall production is the fundamental variable within the Earth's hydrological cycle because it is both the principal forcing term in surface water budgets and its energetics corollary, latent heating, is the principal source of atmospheric diabatic heating. Latent heat release itself is a consequence of phase changes between the vapor, liquid, and frozen states of water. The properties of the vertical distribution of latent heat release modulate large-scale meridional and zonal circulations within the tropics - as well as modifying the energetic efficiencies of midlatitude weather systems. This paper focuses on the retrieval of latent heat release from satellite measurements generated by the Tropical Rainfall Measuring Mission (TRMM) satellite observatory, which was launched in November 1997 as a joint American-Japanese space endeavor. Since then, TRMM measurements have been providing an accurate four-dimensional account of rainfall over the global tropics and sub-tropics, information which can be used to estimate the space-time structure of latent heating across the Earth's low latitudes. The paper examines how the observed TRMM distribution of rainfall has advanced an understanding of the global water and energy cycle and its consequent relationship to the atmospheric general circulation and climate via latent heat release. A set of algorithm methodologies that are being used to estimate latent heating based on rain rate retrievals from the TRMM observations are described. The characteristics of these algorithms and the latent heating products that can be generated from them are also described, along with validation analyses of the heating products themselves. Finally, the investigation provides an overview of how TRMM-derived latent heating information is currently being used in conjunction with global weather and climate models, concluding with remarks intended to stimulate further research on latent heating retrieval from satellites.

Ultrasonic extraction of arsenic and selenium from rocks associated with mountaintop removal/valley fills coal mining: Estimation of bioaccessible concentrations.

PubMed

Pumure, I; Renton, J J; Smart, R B

2010-03-01

Ultrasonic extraction (UE) was used to estimate the total bioaccessible fractions of arsenic and selenium released from rocks associated with mountaintop removal/valley fill coal mining. The combined readily bioaccessible amounts of arsenic and selenium in water soluble, exchangeable and NaOH fractions can be extracted from the solid phase within a 20 or 25 min application of 200 W cm(-2) ultrasound energy in nanopure water for selenium and arsenic, respectively. Application of a two-way ANOVA predicted that there are no significant differences (p0.001, n=12) in the extracted arsenic and selenium concentrations between the combined bioaccessible and ultrasonic extracts. The mechanisms for the UE of arsenic and selenium are thought to involve the formation of secondary minerals on the particle surfaces which eventually dissolve with continued sonication. This is supported by the presence of transient Si-O stretching and OH absorption and bending ATR-FTIR peaks at 795.33 cm(-1), 696.61 cm(-1) and 910.81 cm(-1). The subsequent dissolution of secondary minerals is followed by the release of chemical species that include selenium and arsenic. Release rates decrease after the ultrasound energy elastic limit for the particles is reached. Selenium and arsenic are bound differently within the rock lattice because no selenium was detected in the acid soluble fraction and no arsenic was found in the exchangeable fraction. However, selenium was found in the exchangeable fraction and arsenic was found in the acid soluble fraction. The characterization of coal associated rocks is essential to the design of methodologies and procedures that can be used to control the release of arsenic and selenium from valley fills. Published by Elsevier Ltd.

Comparison of the accident process, radioactivity release and ground contamination between Chernobyl and Fukushima-1

PubMed Central

Imanaka, Tetsuji; Hayashi, Gohei; Endo, Satoru

2015-01-01

In this report, we have reviewed the basic features of the accident processes and radioactivity releases that occurred in the Chernobyl accident (1986) and in the Fukushima-1 accident (2011). The Chernobyl accident was a power-surge accident that was caused by a failure of control of a fission chain reaction, which instantaneously destroyed the reactor and building, whereas the Fukushima-1 accident was a loss-of-coolant accident in which the reactor cores of three units were melted by decay heat after losing the electricity supply. Although the quantity of radioactive noble gases released from Fukushima-1 exceeded the amount released from Chernobyl, the size of land area severely contaminated by 137Cesium (137Cs) was 10 times smaller around Fukushima-1 compared with around Chernobyl. The differences in the accident process are reflected in the composition of the discharged radioactivity as well as in the composition of the ground contamination. Volatile radionuclides (such as 132Te-132I, 131I, 134Cs and 137Cs) contributed to the gamma-ray exposure from the ground contamination around Fukishima-1, whereas a greater variety of radionuclides contributed significantly around Chernobyl. When radioactivity deposition occurred, the radiation exposure rate near Chernobyl is estimated to have been 770 μGy h−1 per initial 137Cs deposition of 1000 kBq m−2, whereas it was 100 μGy h−1 around Fukushima-1. Estimates of the cumulative exposure for 30 years are 970 and 570 mGy per initial deposition of 1000 kBq m−2 for Chernobyl and Fukusima-1, respectively. Of these exposures, 49 and 98% were contributed by radiocesiums (134Cs + 137Cs) around Chernobyl and Fukushima-1, respectively. PMID:26568603

Effect of temperature on endplate potential rundown and recovery in rat diaphragm.

PubMed

Moyer, M; van Lunteren, E

2001-05-01

The amplitude of neuromuscular junction end-plate potentials (EPPs) decreases quickly within a train but recovers nearly completely from train to train during intermittent stimulation. Rundown has been shown to be dependent not only on the rate of transmitter release but also on the rate of replenishment of the depleted neurotransmitter at the site of release. Two groups of processes have been proposed for synaptic vesicle recycling, both of which involve multiple energy-requiring steps and enzymatic reactions and which therefore would be expected to be very temperature-sensitive. The present study tested the hypothesis that low temperature therefore increases the rate of EPP amplitude rundown. Studies were performed in vitro on rat diaphragm and used micro-conotoxin to allow normal-sized EPPs to be recorded from intact fibers. EPP amplitude rundown during intermittent stimulation at 20 and 50 Hz (duty cycle 333 ms) was greater at 20 degrees C than it was at 37 degrees C. Initially, temperature affected only intra-train rundown but, over longer periods of stimulation, both intra- and inter-train rundown were significantly accelerated by cold temperature. Cumulative EPP amplitudes were calculated by successively adding the amplitudes of each EPP during the stimulation period to provide an estimate of total neurotransmitter release in the neuromuscular junction. The cumulative EPP amplitude was significantly lower at 20 degrees C than it was at 37 degrees C during both 20 and 50 Hz stimulation. These data indicate that the mechanism involved in EPP amplitude rundown and recovery is temperature-sensitive, with a greater decrement in EPP amplitude at cold than at warm temperatures.

In vitro kinetic investigations on the bioactivity and cytocompatibility of bioactive glasses prepared via melting and sol-gel techniques for bone regeneration applications.

PubMed

El-Sayed, Mayyada M H; Mostafa, Amany A; Gaafar, Alaa M; El Hotaby, Walid; Hamzawy, Esmat Ma; El-Okaily, Mohamed S; Gamal-Eldeen, Amira M

2017-02-24

This work investigates and compares the influence of the synthesis process on the in vitro bioactivity of two quaternary bioactive glasses prepared via melting and sol-gel (SG) techniques. The two glasses are named MG and SG, respectively. Powder samples were soaked in simulated body fluid for different time intervals to study the kinetics of Ca and P uptake onto their surface as well as Si release. The uptake kinetics followed the pseudo-second order model, and the kinetic parameters in addition to the initial rates were estimated. MG manifested higher Ca uptake capacity than SG which could be attributed to the presence of a residual organic layer capping the surface of SG, as was confirmed by Fourier transform infrared and nuclear magnetic resonance analyses. However, higher rate of Ca uptake was exhibited by SG probably due to its higher reactivity that resulted from its smaller nano-size and higher negative charge as was evident from transmission electron microscopy and dynamic light scattering measurements, respectively. Furthermore, MG showed slightly higher P uptake capacity and lower amount of Si release. Initial rates of Ca and P uptakes onto SG as well as Si release from SG exceeded those of MG. Human bone osteosarcoma cells (Saos-2) were co-cultured with both MG and SG glasses and the latter showed higher alkaline phosphatase activity and higher cell growth induction. The results showed the promising potential of using both bioactive glasses in bone regeneration. However, the choice of the appropriate bioactive glass depends on the targeted applications.

Measurement of semiochemical release rates with a dedicated environmental control system

Treesearch

Heping Zhu; Harold W. Thistle; Christopher M. Ranger; Hongping Zhou; Brian L. Strom

2015-01-01

Insect semiochemical dispensers are commonly deployed under variable environmental conditions over a specified period. Predictions of their longevity are hampered by a lack of methods to accurately monitor and predict how primary variables affect semiochemical release rate. A system was constructed to precisely determine semiochemical release rates under...

40 CFR 302.8 - Continuous releases.

Code of Federal Regulations, 2010 CFR

2010-07-01

... that the release is continuous and stable in quantity and rate; (2) Change in the normal range. If... section, continuous and stable in quantity and rate. (b) Definitions. The following definitions apply to... conditions during the preceding year. Only releases that are both continuous and stable in quantity and rate...

Miniature bulge test and energy release rate in HIPed aluminum/aluminum interfacial fracture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, C.; Lovato, M. L.; Clarke, K. D.

We summarize the development of a technique of using miniature bulge test combined with three-dimensional digital image correlation (3D-DIC) for measuring energy release rate or fracture toughness of bimaterial interface of thin metal foils. Furthermore, the energy release rate associated with the HIPed aluminum/aluminum interfacial delamination is determined experimentally using the proposed technique. Detailed discussions of the schemes of preparing and conducting the bulge test, and computing various quantities required for the determination of the energy release rate are presented.

Miniature bulge test and energy release rate in HIPed aluminum/aluminum interfacial fracture

DOE PAGES

Liu, C.; Lovato, M. L.; Clarke, K. D.; ...

2017-10-13

We summarize the development of a technique of using miniature bulge test combined with three-dimensional digital image correlation (3D-DIC) for measuring energy release rate or fracture toughness of bimaterial interface of thin metal foils. Furthermore, the energy release rate associated with the HIPed aluminum/aluminum interfacial delamination is determined experimentally using the proposed technique. Detailed discussions of the schemes of preparing and conducting the bulge test, and computing various quantities required for the determination of the energy release rate are presented.

Rates of zinc and trace metal release from dissolving sphalerite at pH 2.0-4.0

USGS Publications Warehouse

Stanton, M.R.; Gemery-Hill, P. A.; Shanks, Wayne C.; Taylor, C.D.

2008-01-01

High-Fe and low-Fe sphalerite samples were reacted under controlled pH conditions to determine nonoxidative rates of release of Zn and trace metals from the solid-phase. The release (solubilization) of trace metals from dissolving sphalerite to the aqueous phase can be characterized by a kinetic distribution coefficient, (Dtr), which is defined as [(Rtr/X(tr)Sph)/(RZn/X(Zn) Sph)], where R is the trace metal or Zn release rate, and X is the mole fraction of the trace metal or Zn in sphalerite. This coefficient describes the relationship of the sphalerite dissolution rate to the trace metal mole fraction in the solid and its aqueous concentration. The distribution was used to determine some controls on metal release during the dissolution of sphalerite. Departures from the ideal Dtr of 1.0 suggest that some trace metals may be released via different pathways or that other processes (e.g., adsorption, solubility of trace minerals such as galena) affect the observed concentration of metals. Nonoxidative sphalerite dissolution (mediated by H+) is characterized by a "fast" stage in the first 24-30 h, followed by a "slow" stage for the remainder of the reaction. Over the pH range 2.0-4.0, and for similar extent of reaction (reaction time), sphalerite composition, and surface area, the rates of release of Zn, Fe, Cd, Cu, Mn and Pb from sphalerite generally increase with lower pH. Zinc and Fe exhibit the fastest rates of release, Mn and Pb have intermediate rates of release, and Cd and Cu show the slowest rates of release. The largest variations in metal release rates occur at pH 2.0. At pH 3.0 and 4.0, release rates show less variation and appear less dependent on the metal abundance in the solid. For the same extent of reaction (100 h), rates of Zn release range from 1.53 ?? 10-11 to 5.72 ?? 10-10 mol/m2/s; for Fe, the range is from 4.59 ?? 10-13 to 1.99 ?? 10-10 mol/m2/s. Trace metal release rates are generally 1-5 orders of magnitude slower than the Zn or Fe rates. Results indicate that the distributions of Fe and Cd are directly related to the rate of sphalerite dissolution throughout the reaction at pH 3.0 and 4.0 because these two elements substitute readily into sphalerite. These two metals are likely to be more amenable to usage in predictive acid dissolution models because of this behavior. The Pb distribution shows no strong relation to sphalerite dissolution and appears to be controlled by pH-dependent solubility, most likely related to trace amounts of galena. The distribution of Cu is similar to that of Fe but is the most-dependent of all metals on its mole fraction ratio (Zn:Cu) in sphalerite. The Mn distributions suggest an increase in the rate of Mn release relative to sphalerite dissolution occurs in low Mn samples as pH increases. The Mn distribution in high Mn samples is nearly independent of pH and sphalerite dissolution at pH 2.0 but shows a dependence on these two parameters at higher pH (3.0-4.0).

Release of endogenous amino acids from the hippocampus and brain stem from developing and adult mice in ischemia.

PubMed

Oja, Simo S; Saransaari, Pirjo

2009-09-01

The release of neurotransmitters and modulators has been studied mostly using labeled preloaded compounds. For several reasons, however, the estimated release may not reliably reflect the release of endogenous compounds. The basal and K(+)-evoked release of the neuroactive endogenous amino acids GABA, glycine, taurine, L-glutamate and L-aspartate was now studied in slices from the hippocampus and brain stem from 7-day-old and 3-month-old mice under control and ischemic conditions. The release of synaptically not active L-glutamine, L-alanine, L-threonine and L-serine was assessed for comparison. The estimates for the hippocampus and brainstem were markedly different and also different in developing and adult mice. GABA release was much greater in 3-month-old than in 7-day-old mice, whereas with taurine the situation was the opposite, in the hippocampus in particular. K(+) stimulation enhanced glycine release more in the mature than immature brain stem while in the hippocampus the converse was observed. Ischemia enhanced the release of all neuroactive amino acids in both brain regions, the effects being relatively most pronounced in the case of GABA, aspartate and glutamate in the hippocampus in 3-month-old mice, and taurine in 7-day-old and glycine in 3-month-old mice in the brain stem. These results are qualitatively similar to those obtained on earlier experiments with labeled preloaded amino acids. However, the magnitudes of the release cannot be quite correctly estimated using radioactive labels. In developing mice only taurine release may counteract the harmful effects of excitatory amino acids in ischemia in both hippocampus and brain stem.

Characteristics of CO2 release from forest soil in the mountains near Beijing.

PubMed

Sun, Xiang Yang; Gao, Cheng Da; Zhang, Lin; Li, Su Yan; Qiao, Yong

2011-04-01

CO2 release from forest soil is a key driver of carbon cycling between the soil and atmosphere ecosystem. The rate of CO2 released from soil was measured in three forest stands (in the mountainous region near Beijing, China) by the alkaline absorption method from 2004 to 2006. The rate of CO2 released did not differ among the three stands. The CO2 release rate ranged from - 341 to 1,193 mg m(-2) h(-1), and the mean value over all three forests and sampling times was 286 mg m(-2) h(-1). CO2 release was positively correlated with soil water content and the soil temperature. Diurnally, CO2 release was higher in the day than at night. Seasonally, CO2 release was highest in early autumn and lowest in winter; in winter, negative values of CO2 release suggested that CO2 was absorbed by soil.

Rapid and accurate estimation of release conditions in the javelin throw.

PubMed

Hubbard, M; Alaways, L W

1989-01-01

We have developed a system to measure initial conditions in the javelin throw rapidly enough to be used by the thrower for feedback in performance improvement. The system consists of three subsystems whose main tasks are: (A) acquisition of automatically digitized high speed (200 Hz) video x, y position data for the first 0.1-0.2 s of the javelin flight after release (B) estimation of five javelin release conditions from the x, y position data and (C) graphical presentation to the thrower of these release conditions and a simulation of the subsequent flight together with optimal conditions and flight for the sam release velocity. The estimation scheme relies on a simulation model and is at least an order of magnitude more accurate than previously reported measurements of javelin release conditions. The system provides, for the first time ever in any throwing event, the ability to critique nearly instantly in a precise, quantitative manner the crucial factors in the throw which determine the range. This should be expected to much greater control and consistency of throwing variables by athletes who use system and could even lead to an evolution of new throwing techniques.

Identification of the release history of a groundwater contaminant in non-uniform flow field through the minimum relative entropy method

NASA Astrophysics Data System (ADS)

Cupola, F.; Tanda, M. G.; Zanini, A.

2014-12-01

The interest in approaches that allow the estimation of pollutant source release in groundwater has increased exponentially over the last decades. This is due to the large number of groundwater reclamation procedures that have been carried out: the remediation is expensive and the costs can be easily shared among the different actors if the release history is known. Moreover, a reliable release history can be a useful tool for predicting the plume evolution and for minimizing the harmful effects of the contamination. In this framework, Woodbury and Ulrych (1993, 1996) adopted and improved the minimum relative entropy (MRE) method to solve linear inverse problems for the recovery of the pollutant release history in an aquifer. In this work, the MRE method has been improved to detect the source release history in 2-D aquifer characterized by a non-uniform flow-field. The approach has been tested on two cases: a 2-D homogeneous conductivity field and a strong heterogeneous one (the hydraulic conductivity presents three orders of magnitude in terms of variability). In the latter case the transfer function could not be described with an analytical formulation, thus, the transfer functions were estimated by means of the method developed by Butera et al. (2006). In order to demonstrate its scope, this method was applied with two different datasets: observations collected at the same time at 20 different monitoring points, and observations collected at 2 monitoring points at different times (15-25 monitoring points). The data observed were considered affected by a random error. These study cases have been carried out considering a Boxcar and a Gaussian function as expected value of the prior distribution of the release history. The agreement between the true and the estimated release history has been evaluated through the calculation of the normalized Root Mean Square (nRMSE) error: this has shown the ability of the method of recovering the release history even in the most severe cases. Finally, the forward simulation has been carried out by using the estimated release history in order to compare the true data with the estimated one: the best agreement has been obtained in the homogeneous case, even if also in the heterogenous one the nRMSE is acceptable.

Setting accelerated dissolution test for PLGA microspheres containing peptide, investigation of critical parameters affecting drug release rate and mechanism.

PubMed

Tomic, I; Vidis-Millward, A; Mueller-Zsigmondy, M; Cardot, J-M

2016-05-30

The objective of this study was development of accelerated in vitro release method for peptide loaded PLGA microspheres using flow-through apparatus and assessment of the effect of dissolution parameters (pH, temperature, medium composition) on drug release rate and mechanism. Accelerated release conditions were set as pH 2 and 45°C, in phosphate buffer saline (PBS) 0.02M. When the pH was changed from 2 to 4, diffusion controlled phases (burst and lag) were not affected, while release rate during erosion phase decreased two-fold due to slower ester bonds hydrolyses. Decreasing temperature from 45°C to 40°C, release rate showed three-fold deceleration without significant change in release mechanism. Effect of medium composition on drug release was tested in PBS 0.01M (200 mOsm/kg) and PBS 0.01M with glucose (380 mOsm/kg). Buffer concentration significantly affected drug release rate and mechanism due to the change in osmotic pressure, while ionic strength did not have any effect on peptide release. Furthermore, dialysis sac and sample-and-separate techniques were used, in order to evaluate significance of dissolution technique choice on the release process. After fitting obtained data to different mathematical models, flow-through method was confirmed as the most appropriate for accelerated in vitro dissolution testing for a given formulation. Copyright © 2016 Elsevier B.V. All rights reserved.

Atmospheric Nitrogen Trifluoride: Optimized emission estimates using 2-D and 3-D Chemical Transport Models from 1973-2008

NASA Astrophysics Data System (ADS)

Ivy, D. J.; Rigby, M. L.; Prinn, R. G.; Muhle, J.; Weiss, R. F.

2009-12-01

We present optimized annual global emissions from 1973-2008 of nitrogen trifluoride (NF3), a powerful greenhouse gas which is not currently regulated by the Kyoto Protocol. In the past few decades, NF3 production has dramatically increased due to its usage in the semiconductor industry. Emissions were estimated through the 'pulse-method' discrete Kalman filter using both a simple, flexible 2-D 12-box model used in the Advanced Global Atmospheric Gases Experiment (AGAGE) network and the Model for Ozone and Related Tracers (MOZART v4.5), a full 3-D atmospheric chemistry model. No official audited reports of industrial NF3 emissions are available, and with limited information on production, a priori emissions were estimated using both a bottom-up and top-down approach with two different spatial patterns based on semiconductor perfluorocarbon (PFC) emissions from the Emission Database for Global Atmospheric Research (EDGAR v3.2) and Semiconductor Industry Association sales information. Both spatial patterns used in the models gave consistent results, showing the robustness of the estimated global emissions. Differences between estimates using the 2-D and 3-D models can be attributed to transport rates and resolution differences. Additionally, new NF3 industry production and market information is presented. Emission estimates from both the 2-D and 3-D models suggest that either the assumed industry release rate of NF3 or industry production information is still underestimated.

Diffusion of progestogens through Silastic rubber implants.

PubMed

Lifchez, A S; Scommegna, A

1970-05-01

Silastic rubber capsules in 2 thicknesses (.42 mm and .80 mm) and 3 lengths (9, 14, and 19 mm) were filled with progesterone, Provera, Norgestrel, or chlormadinone acetate and implanted under the skin of rats, and the amount of steroid released was measured after 1, 2, 4, and 8 weeks. The amount of steroid released was also measured from progesterone-filled capsules .42 mm thick and varying from 19-32 mm long inserted in the uterus of 16 women volunteers for 1-7 days. The rate of release of each steroid in the rats was found to be proportionate to the length of the capsule and related, but not proportional to the thickness of the capsule. The release rate of progesterone was 3-20 times greater than that of the other steroids, while Norgestrel diffused at the lowest rate. The influence of thickness of capsule was greater for the steroids with the highest diffusion rate, progesterone and chlormadinone acetate. The release rates of all except chlormadinone acetate were higher in the 1st week. The release rates of the synthetic progestins, unlike that of progesterone, were relatively constant after the 1st week. The release rate of progesterone tended to be related to the amount remaining in the capsule when the amount became small. The measured amount of progesterone released each day from each intrauterine capsule was also proportional to its length. It appears that Norgestrel, Provera, and chlormadinone acetate are all released slowly enough and have enough biologic activity at low concentrations to have a contraceptive effect for well over 1 year when administered in a 30 mm intrauterine capsule.

New insights into differential baroreflex control of heart rate in humans

NASA Technical Reports Server (NTRS)

Fadel, P. J.; Stromstad, M.; Wray, D. W.; Smith, S. A.; Raven, P. B.; Secher, N. H.

2003-01-01

Recent data indicate that bilateral carotid sinus denervation in patients results in a chronic impairment in the rapid reflex control of blood pressure during orthostasis. These findings are inconsistent with previous human experimental investigations indicating a minimal role for the carotid baroreceptor-cardiac reflex in blood pressure control. Therefore, we reexamined arterial baroreflex [carotid (CBR) and aortic baroreflex (ABR)] control of heart rate (HR) using newly developed methodologies. In 10 healthy men, 27 +/- 1 yr old, an abrupt decrease in mean arterial pressure (MAP) was induced nonpharmacologically by releasing a unilateral arterial thigh cuff (300 Torr) after 9 min of resting leg ischemia under two conditions: 1) ABR and CBR deactivation (control) and 2) ABR deactivation. Under control conditions, cuff release decreased MAP by 13 +/- 1 mmHg, whereas HR increased 11 +/- 2 beats/min. During ABR deactivation, neck suction was gradually applied to maintain carotid sinus transmural pressure during the initial 20 s after cuff release (suction). This attenuated the increase in HR (6 +/- 1 beats/min) and caused a greater decrease in MAP (18 +/- 2 mmHg, P < 0.05). Furthermore, estimated cardiac baroreflex responsiveness (DeltaHR/DeltaMAP) was significantly reduced during suction compared with control conditions. These findings suggest that the carotid baroreceptors contribute more importantly to the reflex control of HR than previously reported in healthy individuals.

Predicting the radiation exposure of terrestrial wildlife in the Chernobyl exclusion zone : an international comparison of approaches.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beresford, N. A.; Barnett, C. L.; Brown, J. E.

There is now general acknowledgement that there is a requirement to demonstrate that species other than humans are protected from anthropogenic releases of radioactivity. A number of approaches have been developed for estimating the exposure of wildlife and some of these are being used to conduct regulatory assessments. There is a requirement to compare the outputs of such approaches against available data sets to ensure that they are robust and fit for purpose. In this paper we describe the application of seven approaches for predicting the whole-body ({sup 90}Sr, {sup 137}Cs, {sup 241}Am and Pu isotope) activity concentrations and absorbedmore » dose rates for a range of terrestrial species within the Chernobyl exclusion zone. Predictions are compared against available measurement data, including estimates of external dose rate recorded by thermoluminescent dosimeters attached to rodent species. Potential reasons for differences between predictions between the various approaches and the available data are explored.« less

Effect of the glass transition temperature on alpha-amylase activity in a starch matrix.

PubMed

Chaudhary, Vinita; Panyoyai, Naksit; Small, Darryl M; Shanks, Robert A; Kasapis, Stefan

2017-02-10

This study optimises a protocol for the estimation of α-amylase activity in a condensed starch matrix in the vicinity of the glass transition region. Enzymatic activity on the vitrified starch system was compared with that of a reference substrate, maltodextrin. The activity was assayed as the rate of release of reducing sugar using a dinitrosalicylic acid procedure. The condensed carbohydrate matrices served the dual purpose of acting as a substrate as well as producing a pronounced effect on the ability to enzymatic hydrolysis. Activation energies were estimated throughout the glass transition region of condensed carbohydrate preparations based on the concept of the spectroscopic shift factor. Results were used to demonstrate a considerable moderation by the mechanical glass transition temperature, beyond the expected linear effect of the temperature dependence, on the reaction rate of starch hydrolysis by α-amylase in comparison with the low-molecular weight chain of maltodextrin. Copyright © 2016. Published by Elsevier Ltd.

Maxine: A spreadsheet for estimating dose from chronic atmospheric radioactive releases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jannik, Tim; Bell, Evaleigh; Dixon, Kenneth

MAXINE is an EXCEL© spreadsheet, which is used to estimate dose to individuals for routine and accidental atmospheric releases of radioactive materials. MAXINE does not contain an atmospheric dispersion model, but rather doses are estimated using air and ground concentrations as input. Minimal input is required to run the program and site specific parameters are used when possible. Complete code description, verification of models, and user’s manual have been included.

Movements and survival of black-footed ferrets associated with an experimental translocation in South Dakota

USGS Publications Warehouse

Biggins, D.E.; Godbey, J.L.; Horton, B.M.; Livieri, T.M.

2011-01-01

Black-footed ferrets (Mustela nigripes) apparently were extirpated from all native habitats by 1987, and their repatriation requires a combination of captive breeding, reintroductions, and translocations among sites. Improvements in survival rates of released ferrets have resulted from experience in quasi-natural environments during their rearing. Reestablishment of a self-sustaining wild population by 1999 provided the 1st opportunity to initiate new populations by translocating wild-born individuals. Using radiotelemetry, we compared behaviors and survival of 18 translocated wild-born ferrets and 18 pen-experienced captive-born ferrets after their release into a prairie dog colony not occupied previously by ferrets. Translocated wild-born ferrets moved significantly less and had significantly higher short-term survival rates than their captive-born counterparts. Using markrecapture methods, we also assessed potential impacts to the established donor population of removing 37% of its estimated annual production of kits. Annual survival rates for 30 ferret kits remaining at the donor subcomplex were higher than rates for 54 ferret kits at the control subcomplex (unmanipulated) for males (+82%) and females (+32%). Minimum survival of translocated kits did not differ significantly from survival of those at the control subcomplex. Direct translocation of young, wild-born ferrets from site to site appears to be an efficient method to establish new populations. ?? 2011 American Society of Mammalogists.

Effects of absorption enhancers in chloroquine suppository formulations: I. In vitro release characteristics.

PubMed

Onyeji, C O; Adebayo, A S; Babalola, C P

1999-12-01

The need to develop chloroquine suppository formulations that yield optimal bioavailability of the drug has been emphasized. This study demonstrates the effects of incorporation of known absorption-enhancing agents (nonionic surfactants and sodium salicylate) on the in vitro release characteristics of chloroquine from polyethylene glycol (1000:4000, 75:25%, w/w) suppositories. The release rates were determined using a modification of the continuous flow bead-bed dissolution apparatus for suppositories. Results showed that the extent of drug release from suppositories containing any of three surfactants (Tween 20, Tween 80 and Brij 35) was 100%, whereas 88% release was obtained with control formulation (without enhancer) (P<0.05). However, Tween 20 was more effective than Brij 35 and Tween 80 in improving the drug release rate. There was a concentration-dependent effect with Tween 20, and 4% (w/w) of this surfactant was associated with the highest increase in the rate of drug release from the suppositories. Sodium salicylate at a concentration of 25% (w/w) also significantly enhanced the drug release rate, but a higher concentration of the adjuvant markedly reduced both the rate and extent of drug release. Combined incorporation of Tween 20 and sodium salicylate did not significantly modify (P0.05) the rate of drug release when compared to the effect of the more effective single agent. Due to their effects in improving the drug release profiles coupled with their intrinsic absorption-promoting properties, it is suggested that incorporation of 4% (w/w) Tween 20 and/or 25% (w/w) sodium salicylate in the composite polyethylene glycol chloroquine suppository formulations, may result in enhancement of rectal absorption of the drug. This necessitates an in vivo validation.

Self-reporting bias in Chinook salmon sport fisheries in Idaho: implications for roving creel surveys

USGS Publications Warehouse

McCormick, Joshua L.; Quist, Michael C.; Schill, Daniel J.

2013-01-01

Self-reporting bias in sport fisheries of Chinook Salmon Oncorhynchus tshawytscha in Idaho was quantified by comparing observed and angler-reported data. A total of 164 observed anglers fished for 541 h and caught 74 Chinook Salmon. Fifty-eight fish were harvested and 16 were released. Anglers reported fishing for 604 h, an overestimate of 63 h. Anglers reported catching 66 fish; four less harvested and four less released fish were reported than observed. A Monte Carlo simulation revealed that when angler-reported data were used, total catch was underestimated by 14–15 fish (19–20%) using the ratio-of-means estimator to calculate mean catch rate. Negative bias was reduced to six fish (8%) when the means-of-ratio estimator was used. Multiple linear regression models to predict reporting bias in time fished had poor predictive value. However, actual time fished and a categorical covariate indicating whether the angler fished continuously during their fishing trip were two variables that were present in all of the top a priori models evaluated. Underreporting of catch and overreporting of time fished by anglers present challenges when managing Chinook Salmon sport fisheries. However, confidence intervals were near target levels and using more liberal definitions of angling when estimating effort in creel surveys may decrease sensitivity to bias in angler-reported data.

Population pharmacokinetic modelling of tramadol using inverse Gaussian function for the assessment of drug absorption from prolonged and immediate release formulations.

PubMed

Brvar, Nina; Mateović-Rojnik, Tatjana; Grabnar, Iztok

2014-10-01

This study aimed to develop a population pharmacokinetic model for tramadol that combines different input rates with disposition characteristics. Data used for the analysis were pooled from two phase I bioavailability studies with immediate (IR) and prolonged release (PR) formulations in healthy volunteers. Tramadol plasma concentration-time data were described by an inverse Gaussian function to model the complete input process linked to a two-compartment disposition model with first-order elimination. Although polymorphic CYP2D6 appears to be a major enzyme involved in the metabolism of tramadol, application of a mixture model to test the assumption of two and three subpopulations did not reveal any improvement of the model. The final model estimated parameters with reasonable precision and was able to estimate the interindividual variability of all parameters except for the relative bioavailability of PR vs. IR formulation. Validity of the model was further tested using the nonparametric bootstrap approach. Finally, the model was applied to assess absorption kinetics of tramadol and predict steady-state pharmacokinetics following administration of both types of formulations. For both formulations, the final model yielded a stable estimate of the absorption time profiles. Steady-state simulation supports switching of patients from IR to PR formulation. Copyright © 2014 Elsevier B.V. All rights reserved.

Atmospheric Carbon Dioxide and the Global Carbon Cycle: The Key Uncertainties

DOE R&D Accomplishments Database

Peng, T. H.; Post, W. M.; DeAngelis, D. L.; Dale, V. H.; Farrell, M. P.

1987-12-01

The biogeochemical cycling of carbon between its sources and sinks determines the rate of increase in atmospheric CO{sub 2} concentrations. The observed increase in atmospheric CO{sub 2} content is less than the estimated release from fossil fuel consumption and deforestation. This discrepancy can be explained by interactions between the atmosphere and other global carbon reservoirs such as the oceans, and the terrestrial biosphere including soils. Undoubtedly, the oceans have been the most important sinks for CO{sub 2} produced by man. But, the physical, chemical, and biological processes of oceans are complex and, therefore, credible estimates of CO{sub 2} uptake can probably only come from mathematical models. Unfortunately, one- and two-dimensional ocean models do not allow for enough CO{sub 2} uptake to accurately account for known releases. Thus, they produce higher concentrations of atmospheric CO{sub 2} than was historically the case. More complex three-dimensional models, while currently being developed, may make better use of existing tracer data than do one- and two-dimensional models and will also incorporate climate feedback effects to provide a more realistic view of ocean dynamics and CO{sub 2} fluxes. The instability of current models to estimate accurately oceanic uptake of CO{sub 2} creates one of the key uncertainties in predictions of atmospheric CO{sub 2} increases and climate responses over the next 100 to 200 years.

Rates of opioid dispensing and overdose after introduction of abuse-deterrent extended-release oxycodone and withdrawal of propoxyphene.

PubMed

Larochelle, Marc R; Zhang, Fang; Ross-Degnan, Dennis; Wharam, J Frank

2015-06-01

In the second half of 2010, abuse-deterrent extended-release oxycodone hydrochloride (OxyContin; Purdue Pharma) was introduced and propoxyphene was withdrawn from the US market. The effect of these pharmaceutical market changes on opioid dispensing and overdose rates is unknown. To evaluate the association between 2 temporally proximate changes in the opioid market and opioid dispensing and overdose rates. Claims from a large national US health insurer were analyzed, using an interrupted time series study design. Participants included an open cohort of 31.3 million commercially insured members aged 18 to 64 years between January 1, 2003, and December 31, 2012, with median follow-up of 20 months (last follow-up, December 31, 2012). Introduction of abuse-deterrent OxyContin (resistant to crushing or dissolving) on August 9, 2010, and market withdrawal of propoxyphene on November 19, 2010. Standardized opioid dispensing rates and prescription opioid and heroin overdose rates were the primary outcomes. We used segmented regression to analyze changes in outcomes from 30 quarters before to 8 quarters after the 2 interventions. Two years after the opioid market changes, total opioid dispensing decreased by 19% from the expected rate (absolute change, -32.2 mg morphine-equivalent dose per member per quarter [95% CI, -38.1 to -26.3]). By opioid subtype, the absolute change in dispensing by milligrams of morphine-equivalent dose per member per quarter at 2 years was -11.3 (95% CI, -12.4 to -10.1) for extended-release oxycodone, 3.26 (95% CI, 1.40 to 5.12) for other long-acting opioids, -8.19 (95% CI, -9.30 to -7.08) for propoxyphene, and -16.2 (95% CI, -18.8 to -13.5) for other immediate-release opioids. Two years after the market changes, the estimated overdose rate attributed to prescription opioids decreased by 20% (absolute change, -1.10 per 100,000 members per quarter [95% CI, -1.47 to -0.74]), but heroin overdose increased by 23% (absolute change, 0.26 per 100,000 members per quarter [95% CI, -0.01 to 0.53]). Opioid dispensing and prescription opioid overdoses decreased substantially after 2 major changes in the pharmaceutical market in late 2010. Pharmaceutical market interventions may have value in combatting the prescription opioid overdose epidemic, but heroin overdose rates continue to increase. Complementary strategies to identify and treat opioid abuse and addiction are urgently needed.

Drug Release Studies from Caesalpinia pulcherrima Seed Polysaccharide.

PubMed

Jeevanandham, Somasundaram; Dhachinamoorthi, Duraiswamy; Bannoth Chandra Sekhar, Kothapalli

2011-01-01

This study examines the controlled release behavior of both water-soluble (acetaminophen, caffeine, theophylline and salicylic acid) and water insoluble (indomethacin) drugs derived from Caesalpinia pulcherrima seed Gum isolated from Caesalpinia pulcherrima kernel powder. It further investigates the effect of incorporating diluents such as microcrystalline cellulose and lactose on caffeine release. In addition the effect the gum's (polysaccharide) partial cross-linking had on release of acetaminophen was examined. Applying the exponential equation, the soluble drugs mechanism of release was found to be anomalous. The insoluble drugs showed a near case II or zero order release mechanism. The rate of release in descending order was caffeine, acetaminophen, theophylline, salicylic acid and indomethacin. An increase in the release kinetics of the drug was observed on blending with diluents. However, the rate of release varied with the type and amount of blend within the matrix. The mechanism of release due to effect of diluents was found to be anomalous. The rate of drug release decreased upon partial cross-linking and the mechanism of release was found to be of super case II.

Factors influencing immediate post-release survival of spectacled eiders following surgical implantation of transmitters with percutaneous antennae

USGS Publications Warehouse

Sexson, Matthew G.; Mulcahy, Daniel M.; Spriggs, Maria; Myers, Gwen E.

2014-01-01

Surgically implanted transmitters are a common method for tracking animal movements. Immediately following surgical implantation, animals pass through a critical recovery phase when behaviors may deviate from normal and the likelihood of individual survival may be reduced. Therefore, data collected during this period may be censored to minimize bias introduced by surgery-related behaviors or mortality. However, immediate post-release mortalities negate a sampling effort and reduce the amount of data potentially collected after the censoring period. Wildlife biologists should employ methods to support an animal’s survival through this period, but factors contributing to immediate post-release survival have not been formally assessed. We evaluated factors that potentially influenced the immediate post-release survival of 56 spectacled eiders (Somateria fischeri) marked with coelomically implanted satellite transmitters with percutaneous antennae in northern Alaska in 2010 and 2011. We modeled survival through the first 14 days following release and assessed the relative importance and effect of 15 covariates hypothesized to influence survival during this immediate post-release period. Estimated daily survival rate increased over the duration of the immediate post-release period; the probability of mortality was greatest within the first 5 days following release. Our top-ranking model included the effect of 2 blood analytes, pH and hematocrit, measured prior to surgical implantation of a transmitter. We found a positive response to pH; eiders exhibiting acidemia (low pH) prior to surgery were less likely to survive the immediate post-release period. We found a curvilinear response to hematocrit; eiders exhibiting extremely low or high pre-surgery hematocrit were also less likely to survive the immediate post-release period. In the interest of maximizing the survival of marked birds following release, hematological data obtained prior to surgical implantation of telemetry equipment may be useful when screening for optimal surgical candidates or informing appropriate response to mitigate potentially deleterious disorders such as acidemia.

A comparison of the extended-release and standard-release formulations of tacrolimus in de novo kidney transplant recipients: a 12-month outcome study.

PubMed

Fanous, Helen; Zheng, Rebecca; Campbell, Carolyn; Huang, Michael; Nash, Michelle M; Rapi, Lindita; Zaltzman, Jeffrey S; Prasad, G V Ramesh

2013-02-01

BACKGROUND: Limited comparative data are available on the outcomes between extended-release and standard-release tacrolimus when used de novo in kidney transplant recipients (KTRs). METHODS: We identified KTRs transplanted at our institution during 2009-10 routinely prescribed extended-release tacrolimus and compared them with those transplanted during 2008-09 prescribed standard-release tacrolimus. Graft function (eGFR by MDRD-7 equation) at 12 months post-transplant (primary outcome); new-onset diabetes and other cardiovascular risk factors, BK viremia incidence, acute rejection, and graft survival to 12 months (secondary outcomes) were compared by intent-to-treat analysis. Time-to-steady-state concentration and number of dose adjustments required to attain steady state were recorded. RESULTS: There were no important demographic differences between the extended-release (N = 106) and standard-release (N = 95) cohorts. The estimated glomerular filtration rate (eGFR) at 12 months was similar (58.8 ± 17 versus 59.2 ± 18 mL/min/1.73 m(2), P = 0.307). There was no difference in new-onset diabetes (17 versus 20%, P = 0.581), BK viremia (10 versus 7%, P = 0.450), acute rejection (7 versus 16%, P = 0.067) or graft survival (97 versus 95%, P = 0.301). Time-to-steady state was similar (9.2 ± 1.1 versus 8.1 ± 4.7 days, P = 0.490) although extended-release patients required fewer adjustments to attain steady state (1.2 ± 1.7 [0-8] versus 1.7 ± 1.5 [0-7], P = 0.030) but a similar dose (7.2 ± 2.4 [2-17] versus 7 ± 2.7 [2-16] mg/day, P = 0.697). CONCLUSION: De novo KTRs prescribed extended-release or standard-release tacrolimus demonstrate similar 12-month outcomes.

Carbon emissions from deforestation and forest fragmentation in the Brazilian Amazon

NASA Astrophysics Data System (ADS)

Numata, Izaya; Cochrane, Mark A.; Souza, Carlos M., Jr.; Sales, Marcio H.

2011-10-01

Forest-fragmentation-related edge effects are one of the major causes of forest degradation in Amazonia and their spatio-temporal dynamics are highly influenced by annual deforestation patterns. Rapid biomass collapse due to edge effects in forest fragments has been reported in the Brazilian Amazon; however the collective impacts of this process on Amazonian carbon fluxes are poorly understood. We estimated biomass loss and carbon emissions from deforestation and forest fragmentation related to edge effects on the basis of the INPE (Brazilian National Space Research Institute) PRODES deforestation data and forest biomass volume data. The areas and ages of edge forests were calculated annually and the corresponding biomass loss and carbon emissions from these forest edges were estimated using published rates of biomass decay and decomposition corresponding to the areas and ages of edge forests. Our analysis estimated carbon fluxes from deforestation (4195 Tg C) and edge forest (126-221 Tg C) for 2001-10 in the Brazilian Amazon. The impacts of varying rates of deforestation on regional forest fragmentation and carbon fluxes were also investigated, with the focus on two periods: 2001-5 (high deforestation rates) and 2006-10 (low deforestation rates). Edge-released carbon accounted for 2.6-4.5% of deforestation-related carbon emissions. However, the relative importance of carbon emissions from forest fragmentation increased from 1.7-3.0% to 3.3-5.6% of the respective deforestation emissions between the two contrasting deforestation rates. Edge-related carbon fluxes are of increasing importance for basin-wide carbon accounting, especially as regards ongoing reducing emissions from deforestation and forest degradation (REDD) efforts in Brazilian Amazonia.

Survival and recovery rates of mottled ducks banded in Texas and Louisiana

USGS Publications Warehouse

Haukos, David A.

2015-01-01

The Western Gulf Coast population of the mottled duck (Anas fulvigula) is dependent on the Gulf coastal marsh to complete its entire life cycle. Band recovery data can be used to monitor mottled duck populations by estimating annual survival, indexing harvest rate, and assessing movements. Band returns from hunting seasons 1997–2013 were used to evaluate factors influencing annual survival, recovery rates, and movements of mottled ducks in Texas and Louisiana. For banding years of 1997–2013, 58,349 normal, wild mottled ducks were banded and released in Texas and Louisiana. Since 2002, 86% of mottled duck bandings have occurred on the Chenier Plain of Texas and Louisiana. Hunters shot, recovered, and reported 7,061birds with bands during this period. Direct recovery rates were greater for juveniles than adults but changed little since the 1970s. Estimates of annual survival did not differ between Texas and Louisiana, but did among years and between sex and age classes. Adult male and juvenile female mottled ducks had the greatest and lowest annual survival rates, respectively. Recovery of birds banded on the Chenier Plain was four times greater for birds banded in Texas and harvested in Louisiana than banded in Louisiana and harvested in Texas. Much of the current inference of results from banding mottled ducks is limited to the Chenier Plain. To monitor the entire Western Gulf Coast population of mottled ducks, managers can consider expanding operational banding operations with annual quotas, which would improve survival and recovery estimates and allow for inference beyond the Chenier Plain region.

Simulating future water temperatures in the North Santiam River, Oregon

NASA Astrophysics Data System (ADS)

Buccola, Norman L.; Risley, John C.; Rounds, Stewart A.

2016-04-01

A previously calibrated two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) of Detroit Lake in western Oregon was used in conjunction with inflows derived from Precipitation-Runoff Modeling System (PRMS) hydrologic models to examine in-lake and downstream water temperature effects under future climate conditions. Current and hypothetical operations and structures at Detroit Dam were imposed on boundary conditions derived from downscaled General Circulation Models in base (1990-1999) and future (2059-2068) periods. Compared with the base period, future air temperatures were about 2 °C warmer year-round. Higher air temperature and lower precipitation under the future period resulted in a 23% reduction in mean annual PRMS-simulated discharge and a 1 °C increase in mean annual estimated stream temperatures flowing into the lake compared to the base period. Simulations incorporating current operational rules and minimum release rates at Detroit Dam to support downstream habitat, irrigation, and water supply during key times of year resulted in lower future lake levels. That scenario results in a lake level that is above the dam's spillway crest only about half as many days in the future compared to historical frequencies. Managing temperature downstream of Detroit Dam depends on the ability to blend warmer water from the lake's surface with cooler water from deep in the lake, and the spillway is an important release point near the lake's surface. Annual average in-lake and release temperatures from Detroit Lake warmed 1.1 °C and 1.5 °C from base to future periods under present-day dam operational rules and fill schedules. Simulated dam operations such as beginning refill of the lake 30 days earlier or reducing minimum release rates (to keep more water in the lake to retain the use of the spillway) mitigated future warming to 0.4 and 0.9 °C below existing operational scenarios during the critical autumn spawning period for endangered salmonids. A hypothetical floating surface withdrawal at Detroit Dam improved temperature control in summer and autumn (0.6 °C warmer in summer, 0.6 °C cooler in autumn compared to existing structures) without altering release rates or lake level management rules.

Transient release kinetics of rod bipolar cells revealed by capacitance measurement of exocytosis from axon terminals in rat retinal slices.

PubMed

Oltedal, Leif; Hartveit, Espen

2010-05-01

Presynaptic transmitter release has mostly been studied through measurements of postsynaptic responses, but a few synapses offer direct access to the presynaptic terminal, thereby allowing capacitance measurements of exocytosis. For mammalian rod bipolar cells, synaptic transmission has been investigated in great detail by recording postsynaptic currents in AII amacrine cells. Presynaptic measurements of the dynamics of vesicular cycling have so far been limited to isolated rod bipolar cells in dissociated preparations. Here, we first used computer simulations of compartmental models of morphologically reconstructed rod bipolar cells to adapt the 'Sine + DC' technique for capacitance measurements of exocytosis at axon terminals of intact rod bipolar cells in retinal slices. In subsequent physiological recordings, voltage pulses that triggered presynaptic Ca(2+) influx evoked capacitance increases that were proportional to the pulse duration. With pulse durations 100 ms, the increase saturated at 10 fF, corresponding to the size of a readily releasable pool of vesicles. Pulse durations 400 ms evoked additional capacitance increases, probably reflecting recruitment from additional pools of vesicles. By using Ca(2+) tail current stimuli, we separated Ca(2+) influx from Ca(2+) channel activation kinetics, allowing us to estimate the intrinsic release kinetics of the readily releasable pool, yielding a time constant of 1.1 ms and a maximum release rate of 2-3 vesicles (release site)(1) ms(1). Following exocytosis, we observed endocytosis with time constants ranging from 0.7 to 17 s. Under physiological conditions, it is likely that release will be transient, with the kinetics limited by the activation kinetics of the voltage-gated Ca(2+) channels.

Modeling Patterns of Total Dissolved Solids Release from Central Appalachia, USA, Mine Spoils.

PubMed

Clark, Elyse V; Zipper, Carl E; Daniels, W Lee; Orndorff, Zenah W; Keefe, Matthew J

2017-01-01

Surface mining in the central Appalachian coalfields (USA) influences water quality because the interaction of infiltrated waters and O with freshly exposed mine spoils releases elevated levels of total dissolved solids (TDS) to streams. Modeling and predicting the short- and long-term TDS release potentials of mine spoils can aid in the management of current and future mining-influenced watersheds and landscapes. In this study, the specific conductance (SC, a proxy variable for TDS) patterns of 39 mine spoils during a sequence of 40 leaching events were modeled using a five-parameter nonlinear regression. Estimated parameter values were compared to six rapid spoil assessment techniques (RSATs) to assess predictive relationships between model parameters and RSATs. Spoil leachates reached maximum values, 1108 ± 161 μS cm on average, within the first three leaching events, then declined exponentially to a breakpoint at the 16th leaching event on average. After the breakpoint, SC release remained linear, with most spoil samples exhibiting declines in SC release with successive leaching events. The SC asymptote averaged 276 ± 25 μS cm. Only three samples had SCs >500 μS cm at the end of the 40 leaching events. Model parameters varied with mine spoil rock and weathering type, and RSATs were predictive of four model parameters. Unweathered samples released higher SCs throughout the leaching period relative to weathered samples, and rock type influenced the rate of SC release. The RSATs for SC, total S, and neutralization potential may best predict certain phases of mine spoil TDS release. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Estimation of fish biomass using environmental DNA.

PubMed

Takahara, Teruhiko; Minamoto, Toshifumi; Yamanaka, Hiroki; Doi, Hideyuki; Kawabata, Zen'ichiro

2012-01-01

Environmental DNA (eDNA) from aquatic vertebrates has recently been used to estimate the presence of a species. We hypothesized that fish release DNA into the water at a rate commensurate with their biomass. Thus, the concentration of eDNA of a target species may be used to estimate the species biomass. We developed an eDNA method to estimate the biomass of common carp (Cyprinus carpio L.) using laboratory and field experiments. In the aquarium, the concentration of eDNA changed initially, but reached an equilibrium after 6 days. Temperature had no effect on eDNA concentrations in aquaria. The concentration of eDNA was positively correlated with carp biomass in both aquaria and experimental ponds. We used this method to estimate the biomass and distribution of carp in a natural freshwater lagoon. We demonstrated that the distribution of carp eDNA concentration was explained by water temperature. Our results suggest that biomass data estimated from eDNA concentration reflects the potential distribution of common carp in the natural environment. Measuring eDNA concentration offers a non-invasive, simple, and rapid method for estimating biomass. This method could inform management plans for the conservation of ecosystems.

Estimation of Fish Biomass Using Environmental DNA

PubMed Central

Takahara, Teruhiko; Minamoto, Toshifumi; Yamanaka, Hiroki; Doi, Hideyuki; Kawabata, Zen'ichiro

2012-01-01

Environmental DNA (eDNA) from aquatic vertebrates has recently been used to estimate the presence of a species. We hypothesized that fish release DNA into the water at a rate commensurate with their biomass. Thus, the concentration of eDNA of a target species may be used to estimate the species biomass. We developed an eDNA method to estimate the biomass of common carp (Cyprinus carpio L.) using laboratory and field experiments. In the aquarium, the concentration of eDNA changed initially, but reached an equilibrium after 6 days. Temperature had no effect on eDNA concentrations in aquaria. The concentration of eDNA was positively correlated with carp biomass in both aquaria and experimental ponds. We used this method to estimate the biomass and distribution of carp in a natural freshwater lagoon. We demonstrated that the distribution of carp eDNA concentration was explained by water temperature. Our results suggest that biomass data estimated from eDNA concentration reflects the potential distribution of common carp in the natural environment. Measuring eDNA concentration offers a non-invasive, simple, and rapid method for estimating biomass. This method could inform management plans for the conservation of ecosystems. PMID:22563411

Computing Rates of Small Molecule Diffusion Through Protein Channels Using Markovian Milestoning

NASA Astrophysics Data System (ADS)

Abrams, Cameron

2014-03-01

Measuring diffusion rates of ligands plays a key role in understanding the kinetic processes inside proteins. For example, although many molecular simulation studies have reported free energy barriers to infer rates for CO diffusion in myoglobin (Mb), they typically do not include direct calculation of diffusion rates because of the long simulation times needed to infer these rates with statistical accuracy. We show in this talk how to apply Markovian milestoning along minimum free-energy pathways to calculate diffusion rates of CO inside Mb. In Markovian milestoning, one partitions a suitable reaction coordinate space into regions and performs restrained molecular dynamics in each region to accumulate kinetic statistics that, when assembled across regions, provides an estimate of the mean first-passage time between states. The mean escape time for CO directly from the so-called distal pocket (DP) through the histidine gate (HG) is estimated at about 24 ns, confirming the importance of this portal for CO. But Mb is known to contain several internal cavities, and cavity-to-cavity diffusion rates are also computed and used to build a complete kinetic network as a Markov state model. Within this framework, the effective mean time of escape to the solvent through HG increases to 30 ns. Our results suggest that carrier protein structure may have evolved under pressure to modulate dissolved gas release rates using a network of ligand-accessible cavities. Support: NIH R01GM100472.

Adenoviral vector tethering to metal surfaces via hydrolysable cross-linkers for the modulation of vector release and transduction

PubMed Central

Fishbein, Ilia; Forbes, Scott P.; Chorny, Michael; Connolly, Jeanne M.; Adamo, Richard F.; Corrales, Ricardo; Alferiev, Ivan S.; Levy, Robert J.

2013-01-01

The use of arterial stents and other medical implants as a delivery platform for surface immobilized gene vectors allows for safe and efficient localized expression of therapeutic transgenes. In this study we investigate the use of hydrolysable cross-linkers with distinct kinetics of hydrolysis for delivery of gene vectors from polyallylamine bisphosphonate-modified metal surfaces. Three cross-linkers with the estimated t1/2 of ester bonds hydrolysis of 5, 12 and 50 days demonstrated a cumulative 20%, 39% and 45% vector release, respectively, after 30 days exposure to physiological buffer at 37°C. Transgene expression in endothelial and smooth muscles cells transduced with substrate immobilized adenovirus resulted in significantly different expression profiles for each individual cross-linker. Furthermore, immobilization of adenoviral vectors effectively extended their transduction effectiveness beyond the initial phase of release. Transgene expression driven by adenovirus-tethered stents in rat carotid arteries demonstrated that a faster rate of cross-linker hydrolysis resulted in higher expression levels at day 1, which declined by day 8 after stent implantation, while inversely, slower hydrolysis was associated with increased arterial expression at day 8 in comparison with day 1. In conclusion, adjustable release of transduction-competent adenoviral vectors from metallic surfaces can be achieved, both in vitro and in vivo, through surface immobilization of adenoviral vectors using hydrolysable cross-linkers with structure-specific release kinetics. PMID:23777912

Release and fate of fluorocarbons in a shredder residue landfill cell: 1. Laboratory experiments.

PubMed

Scheutz, Charlotte; Fredenslund, Anders M; Nedenskov, Jonas; Kjeldsen, Peter

2010-11-01

The shredder residues from automobiles, home appliances and other metal-containing products are often disposed in landfills, as recycling technologies for these materials are not common in many countries. Shredder waste contains rigid and soft foams from cushions and insulation panels blown with fluorocarbons. The objective of this study was to use laboratory experiments to estimate fluorocarbon release and attenuation processes in a monofill shredder residue (SR) landfill cell. Waste from the open SR landfill cell at the AV Miljø landfill in Denmark was sampled at three locations. The waste contained 1-3% metal and a relatively low fraction of rigid polyurethane (PUR) foam particles. The PUR waste contained less blowing agent (CFC-11) than predicted from a release model. However, CFC-11 was steadily released in an aerobic bench scale experiment. Anaerobic waste incubation bench tests showed that SRSR produced significant methane (CH(4)), but at rates that were in the low end of the range observed for municipal solid waste. Aerobic and anaerobic batch experiments showed that processes in SRSR potentially can attenuate the fluorocarbons released from the SRSR itself: CFC-11 is degraded under anaerobic conditions with the formation of degradation products, which are being degraded under CH(4) oxidation conditions prevailing in the upper layers of the SR. Copyright © 2010 Elsevier Ltd. All rights reserved.

To what extent do long-duration high-volume dam releases influence river-aquifer interactions? A case study in New South Wales, Australia

NASA Astrophysics Data System (ADS)

Graham, P. W.; Andersen, M. S.; McCabe, M. F.; Ajami, H.; Baker, A.; Acworth, I.

2015-03-01

Long-duration high-volume dam releases are unique anthropogenic events with no naturally occurring equivalents. The impact from such dam releases on a downstream Quaternary alluvial aquifer in New South Wales, Australia, is assessed. It is observed that long-duration (>26 days), high-volume dam releases (>8,000 ML/day average) result in significant variations in river-aquifer interactions. These variations include a flux from the river to the aquifer up to 6.3 m3/day per metre of bank (at distances of up to 330 m from the river bank), increased extent and volume of recharge/bank storage, and a long-term (>100 days) reversal of river-aquifer fluxes. In contrast, during lower-volume events (<2,000 ML/day average) the flux was directed from the aquifer to the river at rates of up to 1.6 m3/day per metre of bank. A groundwater-head prediction model was constructed and river-aquifer fluxes were calculated; however, predicted fluxes from this method showed poor correlation to fluxes calculated using actual groundwater heads. Long-duration high-volume dam releases have the potential to skew estimates of long-term aquifer resources and detrimentally alter the chemical and physical properties of phreatic aquifers flanking the river. The findings have ramifications for improved integrated management of dam systems and downstream aquifers.

Carbon assimilation and transfer through kelp forests in the NE Atlantic is diminished under a warmer ocean climate.

PubMed

Pessarrodona, Albert; Moore, Pippa J; Sayer, Martin D J; Smale, Dan A

2018-06-03

Global climate change is affecting carbon cycling by driving changes in primary productivity and rates of carbon fixation, release and storage within Earth's vegetated systems. There is, however, limited understanding of how carbon flow between donor and recipient habitats will respond to climatic changes. Macroalgal-dominated habitats, such as kelp forests, are gaining recognition as important carbon donors within coastal carbon cycles, yet rates of carbon assimilation and transfer through these habitats are poorly resolved. Here, we investigated the likely impacts of ocean warming on coastal carbon cycling by quantifying rates of carbon assimilation and transfer in Laminaria hyperborea kelp forests-one of the most extensive coastal vegetated habitat types in the NE Atlantic-along a latitudinal temperature gradient. Kelp forests within warm climatic regimes assimilated, on average, more than three times less carbon and donated less than half the amount of particulate carbon compared to those from cold regimes. These patterns were not related to variability in other environmental parameters. Across their wider geographical distribution, plants exhibited reduced sizes toward their warm-water equatorward range edge, further suggesting that carbon flow is reduced under warmer climates. Overall, we estimated that Laminaria hyperborea forests stored ~11.49 Tg C in living biomass and released particulate carbon at a rate of ~5.71 Tg C year -1 . This estimated flow of carbon was markedly higher than reported values for most other marine and terrestrial vegetated habitat types in Europe. Together, our observations suggest that continued warming will diminish the amount of carbon that is assimilated and transported through temperate kelp forests in NE Atlantic, with potential consequences for the coastal carbon cycle. Our findings underline the need to consider climate-driven changes in the capacity of ecosystems to fix and donate carbon when assessing the impacts of climate change on carbon cycling. © 2018 The Authors Global Change Biology Published by John Wiley & Sons Ltd.

The recombination landscape around forensic STRs: Accurate measurement of genetic distances between syntenic STR pairs using HapMap high density SNP data.

PubMed

Phillips, C; Ballard, D; Gill, P; Court, D Syndercombe; Carracedo, A; Lareu, M V

2012-05-01

Family studies can be used to measure the genetic distance between same-chromosome (syntenic) STRs in order to detect physical linkage or linkage disequilibrium. However, family studies are expensive and time consuming, in many cases uninformative, and lack a reliable means to infer the phase of the diplotypes obtained. HapMap provides a more comprehensive and fine-scale estimation of recombination rates using high density multi-point SNP data (average inter-SNP distance: 900 nucleotides). Data at this fine scale detects sub-kilobase genetic distances across the whole recombining human genome. We have used the most recent HapMap SNP data release 22 to measure and compare genetic distances, and by inference fine-scale recombination rates, between 29 syntenic STR pairs identified from 39 validated STRs currently available for forensic use. The 39 STRs comprise 23 core loci: SE33, Penta D & E, 13 CODIS and 7 non-CODIS European Standard Set STRs, plus supplementary STRs in the recently released Promega CS-7™ and Qiagen Investigator HDplex™ kits. Also included were D9S1120, a marker we developed for forensic use unique to chromosome 9, and the novel D6S1043 component STR of SinoFiler™ (Applied Biosystems). The data collated provides reliable estimates of recombination rates between each STR pair, that can then be placed into haplotype frequency calculators for short pedigrees with multiple meiotic inputs and which just requires the addition of allele frequencies. This allows all current STR sets or their combinations to be used in supplemented paternity analyses without the need for further adjustment for physical linkage. The detailed analysis of recombination rates made for autosomal forensic STRs was extended to the more than 50 X chromosome STRs established or in development for complex kinship analyses. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Models for integrated pest control and their biological implications.

PubMed

Tang, Sanyi; Cheke, Robert A

2008-09-01

Successful integrated pest management (IPM) control programmes depend on many factors which include host-parasitoid ratios, starting densities, timings of parasitoid releases, dosages and timings of insecticide applications and levels of host-feeding and parasitism. Mathematical models can help us to clarify and predict the effects of such factors on the stability of host-parasitoid systems, which we illustrate here by extending the classical continuous and discrete host-parasitoid models to include an IPM control programme. The results indicate that one of three control methods can maintain the host level below the economic threshold (ET) in relation to different ET levels, initial densities of host and parasitoid populations and host-parasitoid ratios. The effects of host intrinsic growth rate and parasitoid searching efficiency on host mean outbreak period can be calculated numerically from the models presented. The instantaneous pest killing rate of an insecticide application is also estimated from the models. The results imply that the modelling methods described can help in the design of appropriate control strategies and assist management decision-making. The results also indicate that a high initial density of parasitoids (such as in inundative releases) and high parasitoid inter-generational survival rates will lead to more frequent host outbreaks and, therefore, greater economic damage. The biological implications of this counter intuitive result are discussed.

HIV/AIDS among inmates of and releasees from US correctional facilities, 2006: declining share of epidemic but persistent public health opportunity.

PubMed

Spaulding, Anne C; Seals, Ryan M; Page, Matthew J; Brzozowski, Amanda K; Rhodes, William; Hammett, Theodore M

2009-11-11

Because certain groups at high risk for HIV/AIDS (human immunodeficiency virus/acquired immunodeficiency syndrome) come together in correctional facilities, seroprevalence was high early in the epidemic. The share of the HIV/AIDS epidemic borne by inmates of and persons released from jails and prisons in the United States (US) in 1997 was estimated in a previous paper. While the number of inmates and releasees has risen, their HIV seroprevalence rates have fallen. We sought to determine if the share of HIV/AIDS borne by inmates and releasees in the US decreased between 1997 and 2006. We created a new model of population flow in and out of correctional facilities to estimate the number of persons released in 1997 and 2006. In 1997, approximately one in five of all HIV-infected Americans was among the 7.3 million who left a correctional facility that year. Nine years later, only one in seven (14%) of infected Americans was among the 9.1 million leaving, a 29.3% decline in the share. For black and Hispanic males, two demographic groups with heightened incarceration rates, recently released inmates comprise roughly one in five of those groups' total HIV-infected persons, a figure similar to the proportion borne by the correctional population as a whole in 1997. Decreasing HIV seroprevalence among those admitted to jails and prisons, prolonged survival and aging of the US population with HIV/AIDS beyond the crime-prone years, and success with discharge planning programs targeting HIV-infected prisoners could explain the declining concentration of the epidemic among correctional populations. Meanwhile, the number of persons with HIV/AIDS leaving correctional facilities remains virtually identical. Jails and prisons continue to be potent targets for public health interventions. The fluid nature of incarcerated populations ensures that effective interventions will be felt not only in correctional facilities but also in communities to which releasees return.

Top-down Estimate of Methane Emissions from Natural Gas Production in Northeastern Pennsylvania Using Aircraft and Tower Observations

NASA Astrophysics Data System (ADS)

Barkley, Z.; Lauvaux, T.; Davis, K. J.; Deng, A.; Miles, N. L.; Richardson, S.; Martins, D. K.; Cao, Y.; Sweeney, C.; McKain, K.; Schwietzke, S.; Smith, M. L.; Kort, E. A.

2016-12-01

Leaks in natural gas infrastructure release CH4, a potent greenhouse gas, into the atmosphere. The estimated emission rate associated with the production and transportation of natural gas is uncertain, hindering our understanding of the energy's greenhouse footprint. This study presents two applications of inverse methodology for estimating regional emission rates from natural gas production and gathering facilities in northeastern Pennsylvania. First, we used the WRF-Chem mesoscale model at 3km resolution to simulate CH4 enhancements and compared them to observations obtained from a three-week flight campaign in May 2015 over the Marcellus shale region. Methane emission rates were adjusted to minimize the errors between aircraft observations and the model-simulated concentrations for each flight. Second, we present the first tower-based high resolution atmospheric inversion of CH4 emission rates from unconventional natural gas production activities. A year of continuous CH4 and calibrated δ13C isotope measurements were collected at four tower locations in northeastern Pennsylvania. The adjoint model used here combines a backward-in-time Lagrangian Particle Dispersion Model coupled with the WRF-Chem model at the same resolution. The prior for both optimization systems was compiled for major sources of CH4 within the Mid-Atlantic states, accounting for emissions from natural gas sources as well as emissions related to farming, waste management, coal, and other sources. Optimized natural gas emission rates are found to be 0.36% of total gas production, with a 2σ confidence interval between 0.27-0.45% of production. We present the results from the tower inversion over one year at 3km resolution providing additional information on spatial and temporal variability of emission rates from production and gathering facilities within the natural gas industry in comparison to flux estimates from the aircraft campaign.

Estimating Landfill Methane Oxidation Using the Information of CO2/CH4 Fluxes Measured By the Eddy Covariance Method

NASA Astrophysics Data System (ADS)

Xu, L.; McDermitt, D. K.; Li, J.; Green, R. B.

2016-12-01

Methane plays a critical role in the radiation balance and chemistry of the atmosphere. Globally, landfill methane emission contributes about 10-19% of the anthropogenic methane burden into the atmosphere. In the United States, 18% of annual anthropogenic methane emissions come from landfills, which represent the third largest source of anthropogenic methane emissions, behind enteric fermentation and natural gas and oil production. One uncertainty in estimating landfill methane emissions is the fraction of methane oxidized when methane produced under anaerobic conditions passes through the cover soil. We developed a simple stoichiometric model to estimate the landfill methane oxidation fraction when the anaerobic CO2/CH4 production ratio is known. The model predicts a linear relationship between CO2 emission rates and CH4 emission rates, where the slope depends on anaerobic CO2/CH4 production ratio and the fraction of methane oxidized, and the intercept depends on non-methane-dependent oxidation processes. The model was tested with eddy covariance CO2 and CH4 emission rates at Bluff Road Landfill in Lincoln Nebraska. It predicted zero oxidation rate in the northern portion of this landfill where a membrane and vents were present. The zero oxidation rate was expected because there would be little opportunity for methane to encounter oxidizing conditions before leaving the vents. We also applied the model at the Turkey Run Landfill in Georgia to estimate the CH4 oxidation rate over a one year period. In contrast to Bluff Road Landfill, the Turkey Run Landfill did not have a membrane or vents. Instead, methane produced in the landfill had to diffuse through a 0.5 m soil cap before release to the atmosphere. We observed evidence for methane oxidation ranging from about 18% to above 60% depending upon the age of deposited waste material. The model will be briefly described, and results from the two contrasting landfills will be discussed in this presentation.

Evaluation of angler effort and harvest of rainbow trout (Oncorhynchus mykiss), Lake Scanewa, Washington, 2010

USGS Publications Warehouse

Liedtke, Theresa L.; Kock, Tobias J.; Ekstrom, Brian K.; Tomka, Ryan G.; Rondorf, Dennis W.

2011-01-01

A creel evaluation was conducted in Lake Scanewa, a reservoir on the Cowlitz River, to monitor catch rates of rainbow trout (Oncorhynchus mykiss) and determine if the trout fishery was having negative impacts on juvenile anadromous salmon (Oncorhynchus spp.) in the system. The trout fishery, which is supported by releases of 20,000 fish (2 fish per pound) per year from June to August, was developed to mitigate for the construction of the Cowlitz Falls Dam in 1994. The trout fishery has a target catch rate of at least 0.50 fish per hour. Interviews with 1,214 anglers during the creel evaluation found that most anglers targeted rainbow trout (52 percent) or Chinook and coho salmon (48 percent). The interviewed anglers caught a total of 1,866 fish, most of which were rainbow trout (1,213 fish; 78 percent) or coho salmon (311 fish; 20 percent). We estimated that anglers spent 17,365 hours fishing in Lake Scanewa from June to November 2010. Catch rates for boat anglers (1.39 fish per hour) exceeded the 0.50 fish per hour target, whereas catch rates for shore anglers (0.35 fish per hour) fell short of the goal. The combined catch rates for all trout anglers in the reservoir were 0.96 fish per hour. We estimated that anglers harvested 7,584 (95 percent confidence interval = 2,795-12,372 fish) rainbow trout during the study period and boat anglers caught more fish than shore anglers (5,975 and 1,609 fish, respectively). This estimate suggests that more than 12,000 of the 20,000 rainbow trout released into Lake Scanewa during 2010 were not harvested, and could negatively impact juvenile salmon in the reservoir through predation or competition. We examined 1,236 stomach samples from rainbow trout and found that 2.1 percent (26 fish) of these samples contained juvenile fish. Large trout (greater than 300 millimeters) had a higher incidence of predation than small trout (less than 300 millimeters; 8.50 and 0.06 percent, respectively). A total of 39 fish were found in rainbow trout stomachs and 13 (33 percent) of these were juvenile salmon. These data and uncertainties associated with movement patterns and survival rates of rainbow trout in Lake Scanewa suggest that future evaluations would be helpful to better understand the potential effects of the mitigation trout fishery on juvenile salmon in the reservoir.

CrossWater - Modelling micropollutant loads from different sources in the Rhine basin

NASA Astrophysics Data System (ADS)

Moser, Andreas; Bader, Hans-Peter; Fenicia, Fabrizio; Scheidegger, Ruth; Stamm, Christian

2016-04-01

The pressure on rivers from micropollutants (MPs) originating from various sources is a growing environmental issue and requiring political regulations. The challenges for the water management are numerous, particularly for international water basins. Spatial knowledge of MP sources and the water quality are prerequisites for an effective water quality policy. In this study we analyze the sources of MPs in the international Rhine basin in Europe, and model their transport to the streams. The spatial patterns of MP loads and concentrations from different use classes are investigated with a mass flow analysis and compared to the territorial jurisdictions that shape the spatial arrangement of water management. The source area of MPs depends on the specific use of a compound. Here, we focus on i) herbicides from agricultural land use, ii) biocides from material protection on buildings and iii) human pharmaceuticals from households. The total mass of MPs available for release to the stream network is estimated from statistical application and consumption data. The available mass of MPs is spatially distributed to the catchments areas based on GIS data of agricultural land use, vector data of buildings and wastewater treatment plant (WWTP) locations, respectively. The actual release of MPs to the stream network is calculated with empirical loss rates related to river discharge for agricultural herbicides and to precipitation for biocides. For the pharmaceuticals the release is coupled to the human metabolism rates and elimination rates in WWTP. The released loads from the catchments are propagated downstream with hydraulic routing. Water flow, transport and fate of the substances are simulated within linked river reaches. Time series of herbicide concentrations and loads are simulated for the main rivers in the Rhine basin. Accordingly the loads from the primary catchments are aggregated and constitute lateral or upstream input to the simulated river reaches. Pronounced differences in the spatial patterns of concentrations in the aquatic system are observed between the different compounds. The comparison with measurements from monitoring stations along the Rhine yield satisfactory results.

Use of GRACE determined secular gravity rates for glacial isostatic adjustment studies in North-America

NASA Astrophysics Data System (ADS)

van der Wal, Wouter; Wu, Patrick; Sideris, Michael G.; Shum, C. K.

2008-10-01

Monthly geopotential spherical harmonic coefficients from the GRACE satellite mission are used to determine their usefulness and limitations for studying glacial isostatic adjustment (GIA) in North-America. Secular gravity rates are estimated by unweighted least-squares estimation using release 4 coefficients from August 2002 to August 2007 provided by the Center for Space Research (CSR), University of Texas. Smoothing is required to suppress short wavelength noise, in addition to filtering to diminish geographically correlated errors, as shown in previous studies. Optimal cut-off degrees and orders are determined for the destriping filter to maximize the signal to noise ratio. The halfwidth of the Gaussian filter is shown to significantly affect the sensitivity of the GRACE data (with respect to upper mantle viscosity and ice loading history). Therefore, the halfwidth should be selected based on the desired sensitivity. It is shown that increase in water storage in an area south west of Hudson Bay, from the summer of 2003 to the summer of 2006, contributes up to half of the maximum estimated gravity rate. Hydrology models differ in the predictions of the secular change in water storage, therefore even 4-year trend estimates are influenced by the uncertainty in water storage changes. Land ice melting in Greenland and Alaska has a non-negligible contribution, up to one-fourth of the maximum gravity rate. The estimated secular gravity rate shows two distinct peaks that can possibly be due to two domes in the former Pleistocene ice cover: west and south east of Hudson Bay. With a limited number of models, a better fit is obtained with models that use the ICE-3G model compared to the ICE-5G model. However, the uncertainty in interannual variations in hydrology models is too large to constrain the ice loading history with the current data span. For future work in which GRACE will be used to constrain ice loading history and the Earth's radial viscosity profile, it is important to include realistic uncertainty estimates for hydrology models and land ice melting in addition to the effects of lateral heterogeneity.

The use of sequential mark-release-recapture experiments to estimate population size, survival and dispersal of male mosquitoes of the  Anopheles gambiae complex in Bana, a west African humid savannah village.

PubMed

Epopa, Patric Stephane; Millogo, Abdoul Azize; Collins, Catherine Matilda; North, Ace; Tripet, Frederic; Benedict, Mark Quentin; Diabate, Abdoulaye

2017-08-07

Vector control is a major component of the malaria control strategy. The increasing spread of insecticide resistance has encouraged the development of new tools such as genetic control which use releases of modified male mosquitoes. The use of male mosquitoes as part of a control strategy requires an improved understanding of male mosquito biology, including the factors influencing their survival and dispersal, as well as the ability to accurately estimate the size of a target mosquito population. This study was designed to determine the seasonal variation in population size via repeated mark-release-recapture experiments and to estimate the survival and dispersal of male mosquitoes of the Anopheles gambiae complex in a small west African village. Mark-release-recapture experiments were carried out in Bana Village over two consecutive years, during the wet and the dry seasons. For each experiment, around 5000 (3407-5273) adult male Anopheles coluzzii mosquitoes were marked using three different colour dye powders (red, blue and green) and released in three different locations in the village (centre, edge and outside). Mosquitoes were recaptured at sites spread over the village for seven consecutive days following the releases. Three different capture methods were used: clay pots, pyrethroid spray catches and swarm sampling. Swarm sampling was the most productive method for recapturing male mosquitoes in the field. Population size and survival were estimated by Bayesian analyses of the Fisher-Ford model, revealing an about 10-fold increase in population size estimates between the end of dry season (10,000-50,000) to the wet season (100,000-500,000). There were no detectable seasonal effects on mosquito survival, suggesting that factors other than weather may play an important role. Mosquito dispersal ranged from 40 to 549 m over the seven days of each study and was not influenced by the season, but mainly by the release location, which explained more than 44% of the variance in net dispersal distance. This study clearly shows that male-based MRR experiments can be used to estimate some parameters of wild male populations such as population size, survival, and dispersal and to estimate the spatial patterns of movement in a given locality.

Compliance Monitoring of Yearling and Subyearling Chinook Salmon and Juvenile Steelhead Survival and Passage at John Day Dam, 2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skalski, J. R.; Townsend, Richard L.; Seaburg, Adam

The purpose of this compliance study was to estimate dam passage survival of yearling and subyearling Chinook salmon and steelhead smolts at John Day Dam during the spring and summer outmigrations in 2012. Under the 2008 Federal Columbia River Power System (FCRPS) Biological Opinion (BiOp), dam passage survival should be greater than or equal to 0.96 for spring migrants and greater than or equal to 0.93 for summer migrants, estimated with a standard error (SE) less than or equal to 0.015. The study also estimated smolt passage survival from the forebay 2 km upstream of the dam to the tailracemore » 3 km downstream of the dam, as well as the forebay residence time, tailrace egress time, spill passage efficiency (SPE), and fish passage efficiency (FPE), as required in the Columbia Basin Fish Accords (Fish Accords). A virtual/paired-release design was used to estimate dam passage survival at John Day Dam. The approach included releases of smolts, tagged with acoustic micro-transmitters, above John Day Dam that contributed to the formation of a virtual release at the face of John Day Dam. A survival estimate from this release was adjusted by a paired release below John Day Dam. A total of 3376 yearling Chinook salmon, 5726 subyearling Chinook salmon, and 3239 steelhead smolts were used in the virtual releases. Sample sizes for the below-dam paired releases (R2 and R3, respectively) were 997 and 995 for yearling Chinook salmon smolts, 986 and 983 for subyearling Chinook salmon smolts, and 1000 and 1000 for steelhead smolts. The Juvenile Salmon Acoustic Telemetry System (JSATS) tags were manufactured by Advanced Telemetry Systems. Model SS300 tags, weighing 0.304 g in air, were surgically implanted in yearling and subyearling Chinook salmon, and Model SS130 tag, weighing 0.438 g in air, were surgically implanted in juvenile steelhead for this investigation. The intent of the spring study was to estimate dam passage survival during both 30% and 40% spill conditions. The two spill conditions were to be systematically performed in alternating 2-day test intervals over the course of the spring outmigration. High flow conditions in 2012 interrupted the spill study. Dam passage survival was therefore estimated season-wide regardless of spill conditions.« less

Residual thermal and moisture influences on the strain energy release rate analysis of local delaminations from matrix cracks

NASA Technical Reports Server (NTRS)

Obrien, T. K.

1991-01-01

An analysis utilizing laminated plate theory is developed to calculate the strain energy release rate associated with local delaminations originating at off-axis, single ply, matrix cracks in laminates subjected to uniaxial loads. The analysis includes the contribution of residual thermal and moisture stresses to the strain energy released. Examples are calculated for the strain energy release rate associated with local delaminations originating at 90 degrees and angle-ply (non-90 degrees) matrix ply cracks in glass epoxy and graphite epoxy laminates. The solution developed may be used to assess the relative contribution of mechanical, residual thermal, and moisture stresses on the strain energy release rate for local delamination for a variety of layups and materials.

Escherichia coli Survival in, and Release from, White-Tailed Deer Feces

PubMed Central

Fry, Jessica; Ives, Rebecca L.; Rose, Joan B.

2014-01-01

White-tailed deer are an important reservoir for pathogens that can contribute a large portion of microbial pollution in fragmented agricultural and forest landscapes. The scarcity of experimental data on survival of microorganisms in and release from deer feces makes prediction of their fate and transport less reliable and development of efficient strategies for environment protection more difficult. The goal of this study was to estimate parameters for modeling Escherichia coli survival in and release from deer (Odocoileus virginianus) feces. Our objectives were as follows: (i) to measure survival of E. coli in deer pellets at different temperatures, (ii) to measure kinetics of E. coli release from deer pellets at different rainfall intensities, and (iii) to estimate parameters of models describing survival and release of microorganisms from deer feces. Laboratory experiments were conducted to study E. coli survival in deer pellets at three temperatures and to estimate parameters of Chick's exponential model with temperature correction based on the Arrhenius equation. Kinetics of E. coli release from deer pellets were measured at two rainfall intensities and used to derive the parameters of Bradford-Schijven model of bacterial release. The results showed that parameters of the survival and release models obtained for E. coli in this study substantially differed from those obtained by using other source materials, e.g., feces of domestic animals and manures. This emphasizes the necessity of comprehensive studies of survival of naturally occurring populations of microorganisms in and release from wildlife animal feces in order to achieve better predictions of microbial fate and transport in fragmented agricultural and forest landscapes. PMID:25480751

The Greenville Fault: preliminary estimates of its long-term creep rate and seismic potential

USGS Publications Warehouse

Lienkaemper, James J.; Barry, Robert G.; Smith, Forrest E.; Mello, Joseph D.; McFarland, Forrest S.

2013-01-01

Once assumed locked, we show that the northern third of the Greenville fault (GF) creeps at 2 mm/yr, based on 47 yr of trilateration net data. This northern GF creep rate equals its 11-ka slip rate, suggesting a low strain accumulation rate. In 1980, the GF, easternmost strand of the San Andreas fault system east of San Francisco Bay, produced a Mw5.8 earthquake with a 6-km surface rupture and dextral slip growing to ≥2 cm on cracks over a few weeks. Trilateration shows a 10-cm post-1980 transient slip ending in 1984. Analysis of 2000-2012 crustal velocities on continuous global positioning system stations, allows creep rates of ~2 mm/yr on the northern GF, 0-1 mm/yr on the central GF, and ~0 mm/yr on its southern third. Modeled depth ranges of creep along the GF allow 5-25% aseismic release. Greater locking in the southern two thirds of the GF is consistent with paleoseismic evidence there for large late Holocene ruptures. Because the GF lacks large (>1 km) discontinuities likely to arrest higher (~1 m) slip ruptures, we expect full-length (54-km) ruptures to occur that include the northern creeping zone. We estimate sufficient strain accumulation on the entire GF to produce Mw6.9 earthquakes with a mean recurrence of ~575 yr. While the creeping 16-km northern part has the potential to produce a Mw6.2 event in 240 yr, it may rupture in both moderate (1980) and large events. These two-dimensional-model estimates of creep rate along the southern GF need verification with small aperture surveys.

38 CFR 4.30 - Convalescent ratings.

Code of Federal Regulations, 2010 CFR

2010-07-01

... RATING DISABILITIES General Policy in Rating § 4.30 Convalescent ratings. A total disability rating (100... by report at hospital discharge (regular discharge or release to non-bed care) or outpatient release... total ratings will not be subject to § 3.105(e) of this chapter. Such total rating will be followed by...

Locus of frequency-dependent depression identified with multiple-probability fluctuation analysis at rat climbing fibre-Purkinje cell synapses

PubMed Central

Silver, R Angus; Momiyama, Akiko; Cull-Candy, Stuart G

1998-01-01

EPSCs were recorded under whole-cell voltage clamp at room temperature from Purkinje cells in slices of cerebellum from 12- to 14-day-old rats. EPSCs from individual climbing fibre (CF) inputs were identified on the basis of their large size, paired-pulse depression and all-or-none appearance in response to a graded stimulus. Synaptic transmission was investigated over a wide range of experimentally imposed release probabilities by analysing fluctuations in the peak of the EPSC. Release probability was manipulated by altering the extracellular [Ca2+] and [Mg2+]. Quantal parameters were estimated from plots of coefficient of variation (CV) or variance against mean conductance by fitting a multinomial model that incorporated both spatial variation in quantal size and non-uniform release probability. This ‘multiple-probability fluctuation’ (MPF) analysis gave an estimate of 510 ± 50 for the number of functional release sites (N) and a quantal size (q) of 0.5 ± 0.03 nS (n = 6). Control experiments, and simulations examining the effects of non-uniform release probability, indicate that MPF analysis provides a reliable estimate of quantal parameters. Direct measurement of quantal amplitudes in the presence of 5 mm Sr2+, which gave asynchronous release, yielded distributions with a mean quantal size of 0.55 ± 0.01 nS and a CV of 0.37 ± 0.01 (n = 4). Similar estimates of q were obtained in 2 mm Ca2+ when release probability was lowered with the calcium channel blocker Cd2+. The non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 1 μm) reduced both the evoked current and the quantal size (estimated with MPF analysis) to a similar degree, but did not affect the estimate of N. We used MPF analysis to identify those quantal parameters that change during frequency-dependent depression at climbing fibre-Purkinje cell synaptic connections. At low stimulation frequencies, the mean release probability (P¯r) was unusually high (0.90 ± 0.03 at 0.033 Hz, n = 5), but as the frequency of stimulation was increased, pr fell dramatically (0.02 ± 0.01 at 10 Hz, n = 4) with no apparent change in either q or N. This indicates that the observed 50-fold depression in EPSC amplitude is presynaptic in origin. Presynaptic frequency-dependent depression was investigated with double-pulse and multiple-pulse protocols. EPSC recovery, following simultaneous release at practically all sites, was slow, being well fitted by the sum of two exponential functions (time constants of 0.35 ± 0.09 and 3.2 ± 0.4 s, n = 5). EPSC recovery following sustained stimulation was even slower. We propose that presynaptic depression at CF synapses reflects a slow recovery of release probability following release of each quantum of transmitter. The large number of functional release sites, relatively large quantal size, and unusual dynamics of transmitter release at the CF synapse appear specialized to ensure highly reliable olivocerebellar transmission at low frequencies but to limit transmission at higher frequencies. PMID:9660900

Drug release through liposome pores.

PubMed

Dan, Nily

2015-02-01

Electrical, ultrasound and other types of external fields are known to induce the formation of pores in cellular and model membranes. This paper examines drug release through field induced liposome pores using Monte Carlo simulations. We find that drug release rates vary as a function of pore size and spacing, as well as the overall fraction of surface area covered by pores: The rate of release from liposomes is found to increase rapidly with pore surface coverage, approaching that of the fully ruptured liposome at fractional pore areas. For a given pore surface coverage, the pore size affects the release rate in the limit of low coverage, but not when the pores cover a relatively high fraction of the liposome surface area. On the other hand, for a given pore size and surface coverage, the distribution of pores significantly affects the release in the limit of high surface coverage: The rate of release from a liposome covered with a regularly spaced array of pores is, in this limit, higher than the release rate from (most) systems where the pores are distributed randomly on the liposome surface. In contrast, there is little effect of the pore distribution on release when the pore surface coverage is low. The simulation results are in good agreement with the predictions of detailed diffusion models. Copyright © 2014 Elsevier B.V. All rights reserved.

Passive sampling of DDT, DDE and DDD in sediments: accounting for degradation processes with reaction-diffusion modeling.

PubMed

Tcaciuc, A Patricia; Borrelli, Raffaella; Zaninetta, Luciano M; Gschwend, Philip M

2018-01-24

Passive sampling is becoming a widely used tool for assessing freely dissolved concentrations of hydrophobic organic contaminants in environmental media. For certain media and target analytes, the time to reach equilibrium exceeds the deployment time, and in such cases, the loss of performance reference compounds (PRCs), loaded in the sampler before deployment, is one of the common ways used to assess the fractional equilibration of target analytes. The key assumption behind the use of PRCs is that their release is solely diffusion driven. But in this work, we show that PRC transformations in the sediment can have a measurable impact on the PRC releases and even allow estimation of that compound's transformation rate in the environment of interest. We found that in both field and lab incubations, the loss of the 13 C 2,4'-DDT PRC from a polyethylene (PE) passive sampler deployed at the sediment-water interface was accelerated compared to the loss of other PRCs ( 13 C-labeled PCBs, 13 C-labeled DDE and DDD). The DDT PRC loss was also accompanied by accumulation in the PE of its degradation product, 13 C 2,4'-DDD. Using a 1D reaction-diffusion model, we deduced the in situ degradation rates of DDT from the measured PRC loss. The in situ degradation rates increased with depth into the sediment bed (0.14 d -1 at 0-10 cm and 1.4 d -1 at 30-40 cm) and although they could not be independently validated, these rates compared favorably with literature values. This work shows that passive sampling users should be cautious when choosing PRCs, as degradation processes can affect some PRC's releases from the passive sampler. More importantly, this work opens up the opportunity for novel applications of passive samplers, particularly with regard to investigating in situ degradation rates, pathways, and products for both legacy and emerging contaminants. However, further work is needed to confirm that the rates deduced from model fitting of PRC loss are a true reflection of DDT transformation rates in sediments.

Convergence rates for finite element problems with singularities. Part 1: Antiplane shear. [crack

NASA Technical Reports Server (NTRS)

Plunkett, R.

1980-01-01

The problem of a finite crack in an infinite medium under antiplane shear load is considered. It is shown that the nodal forces at the tip of the crack accurately gives the order of singularity, that n energy release methods can give the strength to better than 1 percent with element size 1/10 the crack length, and that nodal forces give a much better estimate of the stress field than do the elements themselves. The finite element formulation and the factoring of tridiagonal matrices are discussed.

Dust clouds around red giant stars - Evidence of sublimating comet disks?

NASA Technical Reports Server (NTRS)

Matese, John J.; Whitmire, Daniel P.; Reynolds, Ray T.

1989-01-01

The dust production by disk comets around intermediate mass stars evolving into red giants is studied, focusing on AGB supergiants. The model of Iben and Renzini (1983) is used to study the observed dust mass loss for AGB stars. An expression is obtained for the comet disk net dust production rate and values of the radius and black body temperature corresponding to peak sublimation are calculated for a range of stellar masses. Also, the fractional amount of dust released from a cometesimal disk during a classical nova outburst is estimated.

Availability and Distribution of Base Flow in Lower Honokohau Stream, Island of Maui

USGS Publications Warehouse

Fontaine, Richard A.

2003-01-01

Honokohau Stream is one of the few perennial streams in the Lahaina District of West Maui. Current Honokohau water-use practices often lead to conflicts among water users, which are most evident during periods of base flow. To better manage the resource, data are needed that describe the availability and distribution of base flow in lower Honokohau Stream and how base flow is affected by streamflow diversion and return-flow practices. Flow-duration discharges for percentiles ranging from 50 to 95 percent were estimated at 13 locations on lower Honokohau Stream using data from a variety of sources. These sources included (1) available U.S. Geological Survey discharge data, (2) published summaries of Maui Land & Pineapple Company, Inc. diversion and water development-tunnel data, (3) seepage run and low-flow partial-record discharge measurements made for this study, and (4) current (2003) water diversion and return-flow practices. These flow-duration estimates provide a detailed characterization of the distribution and availability of base flow in lower Honokohau Stream. Estimates of base-flow statistics indicate the significant effect of Honokohau Ditch diversions on flow in the stream. Eighty-six percent of the total flow upstream from the ditch is diverted from the stream. Immediately downstream from the diversion dam there is no flow in the stream 91.2 percent of the time, except for minor leakage through the dam. Flow releases at the Taro Gate, from Honokohau Ditch back into the stream, are inconsistent and were found to be less than the target release of 1.55 cubic feet per second on 9 of the 10 days on which measurements were made. Previous estimates of base-flow availability downstream from the Taro Gate release range from 2.32 to 4.6 cubic feet per second (1.5 to 3.0 million gallons per day). At the two principal sites where water is currently being diverted for agricultural use in the valley (MacDonald's and Chun's Dams), base flows of 2.32 cubic feet per second (1.5 million gallons per day) are available more than 95 percent of the time at MacDonald's Dam and 80 percent of the time at Chun's Dam. Base flows of 4.6 cubic feet per second (3.0 million gallons per day) are available 65 and 56 percent of the time, respectively. A base-flow water-accounting model was developed to estimate how flow-duration discharges for 13 sites on Honokohau Stream would change in response to a variety of flow release and diversion practices. A sample application of the model indicates that there is a 1 to 1 relation between changes in flow release rates at the Taro Gate and base flow upstream from MacDonald's Dam. At Chun's Dam the relation between Taro Gate releases and base flow varies with flow-duration percentiles. At the 95th and 60th percentiles, differences in base flow at Chun's Dam would equal about 50 and 90 percent of the change at the Taro Gate.

Controlled release of insect sex pheromones from paraffin wax and emulsions.

PubMed

Atterholt, C A; Delwiche, M J; Rice, R E; Krochta, J M

1999-02-22

Paraffin wax and aqueous paraffin emulsions can be used as controlled release carriers for insect sex pheromones for mating disruption of orchard pests. Paraffin can be applied at ambient temperature as an aqueous emulsion, adheres to tree bark or foliage, releases pheromone for an extended period of time, and will slowly erode from bark and biodegrade in soil. Pheromone emulsions can be applied with simple spray equipment. Pheromone release-rates from paraffin were measured in laboratory flow-cell experiments. Pheromone was trapped from an air stream with an adsorbent, eluted periodically, and quantified by gas chromatography. Pheromone release from paraffin was partition-controlled, providing a constant (zero-order) release rate. A typical paraffin emulsion consisted of 30% paraffin, 4% pheromone, 4% soy oil, 1% vitamin E, 2% emulsifier, and the balance water. Soy oil and vitamin E acted as volatility suppressants. A constant release of oriental fruit moth pheromone from paraffin emulsions was observed in the laboratory for more than 100 days at 27 degreesC, with release-rates ranging from 0.4 to 2 mg/day, depending on the concentration and surface area of the dried emulsion. The use of paraffin emulsions is a viable method for direct application of insect pheromones for mating disruption. Sprayable formulations can be designed to release insect pheromones to the environment at a rate necessary for insect control by mating disruption. At temperatures below 38 degreesC, zero-order release was observed. At 38 degreesC and higher, pheromone oxidation occurred. A partition-controlled release mechanism was supported by a zero-order pheromone release-rate, low air/wax partition coefficients, and pheromone solubility in paraffin.

Liquid-Phase Heat-Release Rates of the Systems Hydrazine-Nitric Acid and Unsymmetrical Dimethylhydrazine-Nitric Acid

NASA Technical Reports Server (NTRS)

Somogyi, Dezso; Feiler, Charles E.

1960-01-01

The initial rates of heat release produced by the reactions of hydrazine and unsymmetrical dimethylhydrazine with nitric acid were determined in a bomb calorimeter under conditions of forced mixing. Fuel-oxidant weight ratio and injection velocity were varied. The rate of heat release apparently depended on the interfacial area between the propellants. Above a narrow range of injection velocities representing a critical amount of interfacial area, the rates reached a maximum and were almost constant with injection velocity. The maximum rate for hydrazine was about 70 percent greater than that for unsymmetrical dimethylhydrazine. The total heat released did not vary with mixture ratio over the range studied.

Effects of pH, Temperature, Dissolved Oxygen, and Flow Rate on Phosphorus Release Processes at the Sediment and Water Interface in Storm Sewer

PubMed Central

Li, Haiyan; Li, Mingyi; Zhang, Xiaoran

2013-01-01

The effects of pH, temperature, dissolved oxygen (DO), and flow rate on the phosphorus (P) release processes at the sediment and water interface in rainwater pipes were investigated. The sampling was conducted in a residential storm sewer of North Li Shi Road in Xi Cheng District of Beijing on August 3, 2011. The release rate of P increased with the increase of pH from 8 to 10. High temperature is favorable for the release of P. The concentration of total phosphorus (TP) in the overlying water increased as the concentration of DO decreased. With the increase of flow rate from 0.7 m s−1 to 1.1 m s−1, the concentration of TP in the overlying water increased and then tends to be stable. Among all the factors examined in the present study, the flow rate is the primary influence factor on P release. The cumulative amount of P release increased with the process of pipeline runoff in the rainfall events with high intensities and shorter durations. Feasible measures such as best management practices and low-impact development can be conducted to control the P release on urban sediments by slowing down the flow rate. PMID:24349823

Rate of Heat Release in Diesel Engines

DOT National Transportation Integrated Search

1977-10-01

In this report, the concept of heat release in diesel engines is compared with reaction rates in petrol engines as a means of describing combustion. The intimate relationships between heat release, cylinder pressure development and cylinder pressure ...

Optimization and development of a core-in-cup tablet for modulated release of theophylline in simulated gastrointestinal fluids.

PubMed

Danckwerts, M P

2000-07-01

A triple-layer core-in-cup tablet that can release theophylline in simulated gastrointestinal (GI) fluids at three distinct rates has been developed. The first layer is an immediate-release layer; the second layer is a sustained-release layer; and the last layer is a boost layer, which was designed to coincide with a higher nocturnal dose of theophylline. The study consisted of two stages. The first stage optimized the sustained-release layer of the tablet to release theophylline over a period of 12 hr. Results from this stage indicated that 30% w/w acacia gum was the best polymer and concentration to use when compressed to a hardness of 50 N/m2. The second stage of the study involved the investigation of the final triple-layer core-in-cup tablet to release theophylline at three different rates in simulated GI fluids. The triple-layer modulated core-in-cup tablet successfully released drug in simulated fluids at an initial rate of 40 mg/min, followed by a rate of 0.4085 mg/min, in simulated gastric fluid TS, 0.1860 mg/min in simulated intestinal fluid TS, and finally by a boosted rate of 0.6952 mg/min.

Summary of Migration and Survival Data from Radio-Tagged Juvenile Coho Salmon in the Trinity River, Northern California, 2008

USGS Publications Warehouse

Beeman, John W.; Hansel, Hal; Juhnke, Steve; Stutzer, Greg

2009-01-01

The survival of hatchery-origin juvenile coho salmon from the Trinity River Hatchery was estimated as they migrated seaward through the Trinity and Klamath Rivers. The purpose of the study was to collect data for comparison to a similar study in the Klamath River and provide data to the Trinity River Restoration Program. A total of 200 fish fitted with radio transmitters were released into the Trinity River near the hatchery (river kilometer 252 from the mouth of the Klamath River) biweekly from March 19 to May 28, 2008. Fish from the earliest release groups took longer to pass the first detection site 10 kilometers downstream of the hatchery than fish from the later release groups, but travel times between subsequent sites were often similar among the release groups. The travel times of individuals through the 239 kilometer study area ranged from 15.5 to 84.6 days with a median of 43.3 days. The data and models did not support differences in survival among release groups, but did support differences among river reaches. The probability of survival in the first 53 kilometers was lower than in the reaches farther downstream, which is similar to trends in juvenile coho salmon in the Klamath River. The lowest estimated survival in this study was in the first 10 kilometers from release in the Trinity River (0.676 SE 0.036) and the highest estimated survival was in the final 20 kilometer reach in the Klamath River (0.987 SE 0.013). Estimated survivals of radio-tagged juvenile coho salmon from release to Klamath River kilometer 33 were 0.639 per 100 kilometers for Trinity River fish and 0.721 per 100 kilometers for Klamath River fish.

Atmospheric emissions from the Windscale accident of October 1957

NASA Astrophysics Data System (ADS)

Garland, J. A.; Wakeford, R.

Although it occurred nearly 50 years ago, the nuclear reactor fire of October 1957 at Windscale Works, Sellafield, England, continues to attract interest. Several attempts have been made to quantify the releases of radionuclides and their radiological consequences, but additional information and a re-analysis of meteorological data encourage a further examination of emissions. The limited instrumentation of the reactor provided little relevant information and, as in previous estimates, the discharges are deduced from environmental evidence, but here the recent meteorological analysis is used. The interpretation of the meteorological and environmental evidence requires both timing and quantity of the emitted radionuclides to be considered together. Significant fission product emission continued from about 15:00 or 16:00 on 10 October 1957 until noon the following day. There were two main peaks in discharge rate, during the evening and early hours and from roughly 06:00 until 10:30, and the amounts emitted during each of these periods were probably comparable. Iodine-131 ( 131I), caesium-137 ( 137Cs) and polonium-210 ( 210Po) activities dominated the radioactive emissions and there is sufficient environmental evidence for releases of these radionuclides to be estimated within a factor of about two. (Some additional 131I may have escaped in a chemical form that was not included in the estimate, but it appears likely that the fraction was small.) There is evidence that the plume extended further east than accepted in previous assessments and the estimates of quantities emitted have been increased to allow for this. For other radionuclides the environmental measurements were fewer and the uncertainties are greater.

Interseismic coupling, seismic potential, and earthquake recurrence on the southern front of the Eastern Alps (NE Italy)

NASA Astrophysics Data System (ADS)

Cheloni, D.; D'Agostino, N.; Selvaggi, G.

2014-05-01

Here we use continuous GPS observations to document the geodetic strain accumulation across the South-Eastern Alps (NE Italy). We estimate the interseismic coupling on the intracontinental collision thrust fault and discuss the seismic potential and earthquake recurrence. We invert the GPS velocities using the back slip approach to simultaneously estimate the relative angular velocity and the degree of interseismic coupling on the thrust fault that separates the Eastern Alps and the Venetian-Friulian plain. Comparison between the rigid rotation predicted motion and the shortening observed across the area indicates that the South-Eastern Alpine thrust front absorbs about 70% of the total convergence between the Adria and Eurasia plates. The coupling is computed on a north dipping fault following the continuous external seismogenic thrust front of the South-Eastern Alps. The modeled thrust fault is currently locked from the surface to a depth of ≈10 km. The transition zone between locked and creeping portions of the fault roughly corresponds with the belt of microseismicity parallel and to the north of the mountain front. The estimated moment deficit rate is 1.3 ± 0.4 × 1017 Nm/yr. The comparison between the estimated moment deficit and that released historically by the earthquakes suggests that to account for the moment deficit the following two factors or their combination should be considered: (1) a significant part of the observed interseismic coupling is released aseismically and (2) infrequent "large" events with long return period (> 1000 years) and with magnitudes larger than the value assigned to the largest historical events (Mw≈ 6.7).

Chemical weathering in a tropical watershed, Luquillo Mountains, Puerto Rico: II. Rate and mechanism of biotite weathering

USGS Publications Warehouse

Murphy, S.F.; Brantley, S.L.; Blum, A.E.; White, A.F.; Dong, H.

1998-01-01

Samples of soil, saprolite, bedrock, and porewater from a lower montane wet forest, the Luquillo Experimental Forest (LEF) in Puerto Rico, were studied to investigate the rates and mechanisms of biotite weathering. The soil profile, at the top of a ridge in the Rio Icacos watershed, consists of a 50-100-cm thick layer of unstructured soil above a 600-800 cm thick saprolite developed on quartz diorite. The only minerals present in significant concentration within the soil and saprolite are biotite, quartz, kaolinite, and iron oxides. Biotite is the only primary silicate releasing significant K and Mg to porewaters. Although biotite in samples of the quartz diorite bedrock is extensively chloritized, chlorite is almost entirely absent in the saprolite phyllosilicates. Phyllosilicate grains are present as 200-1000 ??m wide books below about 50 cm depth. X-ray diffraction (XRD) and electron microprobe analyses indicate that the phyllosilicate grains contain a core of biotite surrounded by variable amounts of kaolinite. Lattice fringe images under transmission electron microscope (TEM) show single layers of biotite altering to two layers of kaolinite, suggesting dissolution of biotite and precipitation of kaolinite at discrete boundaries. Some single 14-A?? layers are also observed in the biotite under TEM. The degree of kaolinitization of individual phyllosilicate grains as observed by TEM decreases with depth in the saprolite. This TEM work is the first such microstructural evidence of epitaxial growth of kaolinite onto biotite during alteration in low-temperature environments. The rate of release of Mg in the profile, calculated as a flux through the soil normalized per watershed land area, is approximately 500 mol hectare-1 yr-1 (1.6 ?? 10-9 molMg m-2soil s-1). This rate is similar to the flux estimated from Mg discharge out the Rio Icacos (1000 mol hectare-1 yr-1, or 3.5 ?? 10-9 molMg m-2soil s-1), indicating that scaling up from the soil to the watershed is possible for Mg release. The rate of Mg release from biotite, normalized to Brunauer-Emmett-Teller (BET) surface area, is calculated using a mass balance equation which includes the density and volume of phyllosilicate grains, porewater chemistry and flux, and soil porosity. The mean rates of biotite weathering calculated from K and Mg release rates are approximately 6 and 11 ?? 10-16 molbiotite m-2biotite s-1 respectively, significantly slower than laboratory rates (10-12 to 10-11 molbiotite m-2biotite s-1). The discrepancy in scaling down from the soil to the laboratory is probably explained by (1) differences in weathering mechanism between the two environments, (2) higher solute concentrations in soil porewaters, (3) loss of reactive surface area of biotite in the saprolite due to kaolinite and iron oxide coatings, and/or (4) unaccounted-for heterogeneities in flow path through the soil. Copyright ?? 1998 Elsevier Science Ltd.

Effect of detention basin release rates on flood flows - Application of a model to the Blackberry Creek Watershed in Kane County, Illinois

USGS Publications Warehouse

Soong, David T.; Murphy, Elizabeth A.; Straub, Timothy D.

2009-01-01

The effects of stormwater detention basins with specified release rates are examined on the watershed scale with a Hydrological Simulation Program - FORTRAN (HSPF) continuous-simulation model. Modeling procedures for specifying release rates from detention basins with orifice and weir discharge configurations are discussed in this report. To facilitate future detention modeling as a tool for watershed management, a chart relating watershed impervious area to detention volume is presented. The report also presents a case study of the Blackberry Creek watershed in Kane County, Ill., a rapidly urbanizing area seeking to avoid future flood damages from increased urbanization, to illustrate the effects of various detention basin release rates on flood peaks and volumes and flood frequencies. The case study compares flows simulated with a 1996 land-use HSPF model to those simulated with four different 2020 projected land-use HSPF model scenarios - no detention, and detention basins with release rates of 0.08, 0.10, and 0.12 cubic feet per second per acre (ft3/s-acre), respectively. Results of the simulations for 15 locations, which included the downstream ends of all tributaries and various locations along the main stem, showed that a release rate of 0.10 ft3/s-acre, in general, can maintain postdevelopment 100-year peak-flood discharge at a similar magnitude to that of 1996 land-use conditions. Although the release rate is designed to reduce the 100-year peak flow, reduction of the 2-year peak flow is also achieved for a smaller proportion of the peak. Results also showed that the 0.10 ft3/s-acre release rate was less effective in watersheds with relatively high percentages of preexisting (1996) development than in watersheds with less preexisting development.

New constraints on the rupture process of the 1999 August 17 Izmit earthquake deduced from estimates of stress glut rate moments

NASA Astrophysics Data System (ADS)

Clévédé, E.; Bouin, M.-P.; Bukchin, B.; Mostinskiy, A.; Patau, G.

2004-12-01

This paper illustrates the use of integral estimates given by the stress glut rate moments of total degree 2 for constraining the rupture scenario of a large earthquake in the particular case of the 1999 Izmit mainshock. We determine the integral estimates of the geometry, source duration and rupture propagation given by the stress glut rate moments of total degree 2 by inverting long-period surface wave (LPSW) amplitude spectra. Kinematic and static models of the Izmit earthquake published in the literature are quite different from one another. In order to extract the characteristic features of this event, we calculate the same integral estimates directly from those models and compare them with those deduced from our inversion. While the equivalent rupture zone and the eastward directivity are consistent among all models, the LPSW solution displays a strong unilateral character of the rupture associated with a short rupture duration that is not compatible with the solutions deduced from the published models. With the aim of understand this discrepancy, we use simple equivalent kinematic models to reproduce the integral estimates of the considered rupture processes (including ours) by adjusting a few free parameters controlling the western and eastern parts of the rupture. We show that the joint analysis of the LPSW solution and source tomographies allows us to elucidate the scattering of source processes published for this earthquake and to discriminate between the models. Our results strongly suggest that (1) there was significant moment released on the eastern segment of the activated fault system during the Izmit earthquake; (2) the apparent rupture velocity decreases on this segment.

Dynamics of tropical oxygen minium zones (OMZ): The role of vertical mixing and eddy stirring in ventilating the OMZ in the tropical Atlantic

NASA Astrophysics Data System (ADS)

Visbeck, M.; Banyte, D.; Brandt, P.; Dengler, M.; Fischer, T.; Karstensen, J.; Krahmann, G.; Tanhua, T. S.; Stramma, L.

2013-12-01

Equatorial Dynamics provide an essential influence on the ventilation pathways of well oxygenated surface water on their route to tropical oxygen minimum zones (OMZ). The large scale wind driven circulation shield OMZs from the direct ventilation pathways. They are located in the so called ';shadow zones' equator ward of the subtropical gyres. From what is known most of the oxygen is supplied via pathways from the western boundary modulated by the complex zonal equatorial current system and marginally by vertical mixing. What was less clear is which of the possible pathways are most effective in transporting dissolved oxygen towards the OMZ. A collaborative research program focused on the dynamics of oxygen minimum zones, called SFB754 "Climate - Biogeochemistry Interactions in the Tropical Ocean", allowed us to conduct two ocean tracer release experiments to investigate the vertical and horizontal mixing rates and associated oxygen transports. Specifically we report on the first deliberate tracer release experiment (GUTRE, Guinea Upwelling Tracer Release Experiment) in the tropical northeast Atlantic carried out in order to determine the diapycnal diffusivity coefficient in the upper layer of the OMZ. A tracer (CF3SF5) was injected in spring of 2008 and subsequently measured during three designated tracer survey cruises until the end of 2010. We found that, generally, the diffusivity is larger than expected for low latitudes and similar in magnitude to what has previously been experimentally determined in the Canary Basin. When combining the tracer study with estimates of diapycnal mixing based on microstructure profiling and a newly developed method using ship board ADCPs we were able to compute the vertical oxygen flux and its divergence for the OMZ. To our surprise, the vertical flux of oxygen by diapycnal mixing provides about 30% of the total ventilation. The estimate was derived from the simple advection-diffusion model taking into account moored and ship based velocity observations of the equatorial current systems along 23°W in the tropical Atlantic. However, the advective pathways are less certain and possibly more variable. Firstly, the strength of lateral eddy stirring and the role in oxygen transport is less well known, and is the focus of the ongoing second tracer release experiment (OSTRE, Oxygen Supply Tracer Release Experiment). Secondly, the analysis of historical data from the equatorial regime suggests that the observed decline in dissolved oxygen in the tropical North Atlantic might in part be a consequence of reduced horizontal ventilation by equatorial intermediate current systems. The uncertainty of the long-term variability of the circulation in the equatorial systems and additional uncertainty in the biogeochemical consumption rates provide a challenge for estimates of the future of the OMZ regimes. Model prediction of future oxygen changes depend on the models ability to reproduce the observed oxygen ventilation pathways and processes, which might limit the prediction's accuracy.

[Effect on iron release in drinking water distribution systems].

PubMed

Niu, Zhang-bin; Wang, Yang; Zhang, Xiao-jian; Chen, Chao; Wang, Sheng-hui

2007-10-01

Batch-scale experiments were done to quantitatively study the effect of inorganic chemical parameters on iron release in drinking water distribution systems. The parameters include acid-base condition, oxidation-reduction condition, and neutral ion condition. It was found that the iron release rate decreased with pH, alkalinity, the concentration of dissolved oxygen increasing, and the iron release rate increased with the concentration of chloride increasing. The theoretical critical formula of iron release rate was elucidated. According to the formula, the necessary condition for controlling iron release is that pH is above 7.6, the concentration of alkalinity and dissolved oxygen is more than 150 mg/L and 2 mg/L, and the concentration of chloride is less than 150 mg/L of distributed water.

ATMOSPHERIC RELEASES OF HEXAVALENT CHROMIUM FROM HARD CHROMIUM PLATING OPERATIONS

EPA Science Inventory

The University of Central Florida Department of Civil and Environmental Engineering is investigating methods for improved estimation of chemical releases which require reporting under provisions of SARA Title III (Toxic Release Inventory, Form R). This paper describes results fr...

Reducing errors in aircraft atmospheric inversion estimates of point-source emissions: the Aliso Canyon natural gas leak as a natural tracer experiment

NASA Astrophysics Data System (ADS)

Gourdji, S. M.; Yadav, V.; Karion, A.; Mueller, K. L.; Conley, S.; Ryerson, T.; Nehrkorn, T.; Kort, E. A.

2018-04-01

Urban greenhouse gas (GHG) flux estimation with atmospheric measurements and modeling, i.e. the ‘top-down’ approach, can potentially support GHG emission reduction policies by assessing trends in surface fluxes and detecting anomalies from bottom-up inventories. Aircraft-collected GHG observations also have the potential to help quantify point-source emissions that may not be adequately sampled by fixed surface tower-based atmospheric observing systems. Here, we estimate CH4 emissions from a known point source, the Aliso Canyon natural gas leak in Los Angeles, CA from October 2015–February 2016, using atmospheric inverse models with airborne CH4 observations from twelve flights ≈4 km downwind of the leak and surface sensitivities from a mesoscale atmospheric transport model. This leak event has been well-quantified previously using various methods by the California Air Resources Board, thereby providing high confidence in the mass-balance leak rate estimates of (Conley et al 2016), used here for comparison to inversion results. Inversions with an optimal setup are shown to provide estimates of the leak magnitude, on average, within a third of the mass balance values, with remaining errors in estimated leak rates predominantly explained by modeled wind speed errors of up to 10 m s‑1, quantified by comparing airborne meteorological observations with modeled values along the flight track. An inversion setup using scaled observational wind speed errors in the model-data mismatch covariance matrix is shown to significantly reduce the influence of transport model errors on spatial patterns and estimated leak rates from the inversions. In sum, this study takes advantage of a natural tracer release experiment (i.e. the Aliso Canyon natural gas leak) to identify effective approaches for reducing the influence of transport model error on atmospheric inversions of point-source emissions, while suggesting future potential for integrating surface tower and aircraft atmospheric GHG observations in top-down urban emission monitoring systems.

Advanced risk assessment of the effects of graphite fibers on electronic and electric equipment, phase 1. [simulating vulnerability to airports and communities from fibers released during aircraft fires

NASA Technical Reports Server (NTRS)

Pocinki, L. S.; Kaplan, L. D.; Cornell, M. E.; Greenstone, R.

1979-01-01

A model was developed to generate quantitative estimates of the risk associated with the release of graphite fibers during fires involving commercial aircraft constructed with graphite fiber composite materials. The model was used to estimate the risk associated with accidents at several U.S. airports. These results were then combined to provide an estimate of the total risk to the nation.

Wax-based sustained release matrix pellets prepared by a novel freeze pelletization technique II. In vitro drug release studies and release mechanisms.

PubMed

Cheboyina, Sreekhar; Wyandt, Christy M

2008-07-09

A novel freeze pelletization technique was evaluated for the preparation of wax-based sustained release matrix pellets. Pellets containing water-soluble drugs were successfully prepared using a variety of waxes. The drug release significantly depended on the wax type used and the aqueous drug solubility. The drug release decreased as the hydrophobicity of wax increased and the drug release increased as the aqueous drug solubility increased. In glyceryl monostearate (GMS) pellets, drug release rate decreased as the loading of theophylline increased. On the contrary, the release rate increased as the drug loading of diltiazem HCl increased in Precirol pellets. Theophylline at low drug loads existed in a dissolved state in GMS pellets and the release followed desorption kinetics. At higher loads, theophylline existed in a crystalline state and the release followed dissolution-controlled constant release for all the waxes studied. However, with the addition of increasing amounts of Brij 76, theophylline release rate increased and the release mechanism shifted to diffusion-controlled square root time kinetics. But the release of diltiazem HCl from Precirol pellets at all drug loads, followed diffusion-controlled square root time kinetics. Therefore, pellets capable of providing a variety of release profiles for different drugs can be prepared using this freeze pelletization technique by suitably modifying the pellet forming matrix compositions.

Release kinetics of vanadium from vanadium (III, IV and V) oxides: Effect of pH, temperature and oxide dose.

PubMed

Hu, Xingyun; Yue, Yuyan; Peng, Xianjia

2018-05-01

Batch experiments were performed to derive the rate laws for the proton-promoted dissolution of the main vanadium (III, IV and V) oxides at pH 3.1-10.0. The release rates of vanadium are closely related to the aqueous pH, and several obvious differences were observed in the release behavior of vanadium from the dissolution of V 2 O 5 and vanadium(III, IV) oxides. In the first 2hr, the release rates of vanadium from V 2 O 3 were r=1.14·([H + ]) 0.269 at pH 3.0-6.0 and r=0.016·([H + ]) -0.048 at pH 6.0-10.0; the release rates from VO 2 were r=0.362·([H + ]) 0.129 at pH 3.0-6.0 and r=0.017·([H + ]) -0.097 at pH 6.0-10.0; and the release rates from V 2 O 5 were r=0.131·([H + ]) -0.104 at pH 3.1-10.0. The release rates of vanadium from the three oxides increased with increasing temperature, and the effect of temperature was different at pH 3.8, pH 6.0 and pH 7.7. The activation energies of vanadium (III, IV and V) oxides (33.4-87.5kJ/mol) were determined at pH 3.8, pH6.0 and pH 7.7, showing that the release of vanadium from dissolution of vanadium oxides follows a surface-controlled reaction mechanism. The release rates of vanadium increased with increasing vanadium oxides dose, albeit not proportionally. This study, as part of a broader study of the release behavior of vanadium, can help to elucidate the pollution problem of vanadium and to clarify the fate of vanadium in the environment. Copyright © 2017. Published by Elsevier B.V.

Survival of angled saugers in the lower Tennessee River

USGS Publications Warehouse

Kitterman, Christy L.; Bettoli, Phillip William

2011-01-01

An intense winter fishery for sauger Sander canadensis exists in the lower Tennessee River, and the objective of this study was to estimate the survival of angled saugers. In February 2008 and January–March 2009, 81 angled saugers (72 live plus 9 euthanized) were affixed with ultrasonic tags. The movements (or lack thereof) by saugers released alive were compared with those of euthanized fish to assess survival. Sixty-eight percent of the tagged saugers that were released alive exhibited maximum daily movements exceeding the greatest movement of any euthanized fish (0.5 km/d), and those fish were subsequently classified as survivors. The upstream movements of several euthanized fish indicated that their carcasses were ingested by piscivorous scavengers. In logistic models, the probability of mortality was significantly and inversely related to total length but not to capture depth, water temperature, handling time, or ascent rate. In 2 × 2 contingency tables, the fate of released saugers was not found to be associated with either the presence or absence of bleeding from the hooking wound or whether or not the fish displayed gastric distension. Most released fish survived despite the fact that gastric distension was observed in 72% of the angled saugers.

Secular Climate Change on Mars: An Update Using MSL Pressure Data

NASA Technical Reports Server (NTRS)

Haberle, R. M.; Gomez-Elvira, J.; Juarez, M. de la Torre; Harri, A.-M.; Hollingsworth, J. L.; Kahanpaa, H.; Kahre, M. A.; Lemmon, M.; Martin-Torres, F. J.; Mischna, M.;

The VCOP Scale: a measure of overprotection in parents of physically vulnerable children.

PubMed

Wright, L; Mullen, T; West, K; Wyatt, P

1993-11-01

A scale is developed for measuring the overprotecting vs. optimal developmental stimulation tendencies for parents of physically "vulnerable" children. A series of items were administered to parents whose parenting techniques had been rated as either highly overprotective or as optimal by a group of MDs and other professionals. Correlations were estimated between each of the items and parental tendencies as rated by professionals. Twenty-eight items were selected that provided maximum prediction of over-protection. The resulting R2 was extraordinarily high (.94). Coefficient alpha and test-retest coefficients were acceptable. It is hoped that release of the new instrument (VCOPS) at this time will allow others to join in determining the clinical and experimental validity of this scale.

The Roles of Parasitoid Foraging for Hosts, Food and Mates in the Augmentative Control of Tephritidae

PubMed Central

Sivinski, John; Aluja, Martin

2012-01-01

Ultimately, the success of augmentative fruit fly biological control depends upon the survival, dispersal, attack rate and multi-generational persistence of mass-reared parasitoids in the field. Foraging for hosts, food and mates is fundamental to the above and, at an operational level, the choice of the parasitoid best suited to control a particular tephritid in a certain environment, release rate estimates and subsequent monitoring of effectiveness. In the following we review landscape-level and microhabitat foraging preferences, host/fruit ranges, orientation through environmental cues, host vulnerabilities/ovipositor structures, and inter and intraspecific competition. We also consider tephritid parasitoid mating systems and sexual signals, and suggest the directions of future research. PMID:26466622

Iron catalyst chemistry in modeling a high-pressure carbon monoxide nanotube reactor

NASA Technical Reports Server (NTRS)

Scott, Carl D.; Povitsky, Alexander; Dateo, Christopher; Gokcen, Tahir; Willis, Peter A.; Smalley, Richard E.

2003-01-01

The high-pressure carbon monoxide (HiPco) technique for producing single-wall carbon nanotubes (SWNTs) is analyzed with the use of a chemical reaction model coupled with flow properties calculated along streamlines, calculated by the FLUENT code for pure carbon monoxide. Cold iron pentacarbonyl, diluted in CO at about 30 atmospheres, is injected into a conical mixing zone, where hot CO is also introduced via three jets at 30 degrees with respect to the axis. Hot CO decomposes the Fe(CO)5 to release atomic Fe. Then iron nucleates and forms clusters that catalyze the formation of SWNTs by a disproportionation reaction (Boudouard) of CO on Fe-containing clusters. Alternative nucleation rates are estimated from the theory of hard sphere collision dynamics with an activation energy barrier. The rate coefficient for carbon nanotube growth is estimated from activation energies in the literature. The calculated growth was found be about an order of magnitude greater than measured, regardless of the nucleation rate. A study of cluster formation in an incubation zone prior to injection into the reactor shows that direct dimer formation from Fe atoms is not as important as formation via an exchange reaction of Fe with CO in FeCO.

Iron catalyst chemistry in modeling a high-pressure carbon monoxide nanotube reactor.

PubMed

Scott, Carl D; Povitsky, Alexander; Dateo, Christopher; Gökçen, Tahir; Willis, Peter A; Smalley, Richard E

2003-01-01

The high-pressure carbon monoxide (HiPco) technique for producing single-wall carbon nanotubes (SWNTs) is analyzed with the use of a chemical reaction model coupled with flow properties calculated along streamlines, calculated by the FLUENT code for pure carbon monoxide. Cold iron pentacarbonyl, diluted in CO at about 30 atmospheres, is injected into a conical mixing zone, where hot CO is also introduced via three jets at 30 degrees with respect to the axis. Hot CO decomposes the Fe(CO)5 to release atomic Fe. Then iron nucleates and forms clusters that catalyze the formation of SWNTs by a disproportionation reaction (Boudouard) of CO on Fe-containing clusters. Alternative nucleation rates are estimated from the theory of hard sphere collision dynamics with an activation energy barrier. The rate coefficient for carbon nanotube growth is estimated from activation energies in the literature. The calculated growth was found be about an order of magnitude greater than measured, regardless of the nucleation rate. A study of cluster formation in an incubation zone prior to injection into the reactor shows that direct dimer formation from Fe atoms is not as important as formation via an exchange reaction of Fe with CO in FeCO.

Sensitivity analysis of radionuclides atmospheric dispersion following the Fukushima accident

NASA Astrophysics Data System (ADS)

Girard, Sylvain; Korsakissok, Irène; Mallet, Vivien

2014-05-01

Atmospheric dispersion models are used in response to accidental releases with two purposes: - minimising the population exposure during the accident; - complementing field measurements for the assessment of short and long term environmental and sanitary impacts. The predictions of these models are subject to considerable uncertainties of various origins. Notably, input data, such as meteorological fields or estimations of emitted quantities as function of time, are highly uncertain. The case studied here is the atmospheric release of radionuclides following the Fukushima Daiichi disaster. The model used in this study is Polyphemus/Polair3D, from which derives IRSN's operational long distance atmospheric dispersion model ldX. A sensitivity analysis was conducted in order to estimate the relative importance of a set of identified uncertainty sources. The complexity of this task was increased by four characteristics shared by most environmental models: - high dimensional inputs; - correlated inputs or inputs with complex structures; - high dimensional output; - multiplicity of purposes that require sophisticated and non-systematic post-processing of the output. The sensitivities of a set of outputs were estimated with the Morris screening method. The input ranking was highly dependent on the considered output. Yet, a few variables, such as horizontal diffusion coefficient or clouds thickness, were found to have a weak influence on most of them and could be discarded from further studies. The sensitivity analysis procedure was also applied to indicators of the model performance computed on a set of gamma dose rates observations. This original approach is of particular interest since observations could be used later to calibrate the input variables probability distributions. Indeed, only the variables that are influential on performance scores are likely to allow for calibration. An indicator based on emission peaks time matching was elaborated in order to complement classical statistical scores which were dominated by deposit dose rates and almost insensitive to lower atmosphere dose rates. The substantial sensitivity of these performance indicators is auspicious for future calibration attempts and indicates that the simple perturbations used here may be sufficient to represent an essential part of the overall uncertainty.

Assessing the Accuracy of the Tracer Dilution Method with Atmospheric Dispersion Modeling

NASA Astrophysics Data System (ADS)

Taylor, D.; Delkash, M.; Chow, F. K.; Imhoff, P. T.

2015-12-01

Landfill methane emissions are difficult to estimate due to limited observations and data uncertainty. The mobile tracer dilution method is a widely used and cost-effective approach for predicting landfill methane emissions. The method uses a tracer gas released on the surface of the landfill and measures the concentrations of both methane and the tracer gas downwind. Mobile measurements are conducted with a gas analyzer mounted on a vehicle to capture transects of both gas plumes. The idea behind the method is that if the measurements are performed far enough downwind, the methane plume from the large area source of the landfill and the tracer plume from a small number of point sources will be sufficiently well-mixed to behave similarly, and the ratio between the concentrations will be a good estimate of the ratio between the two emissions rates. The mobile tracer dilution method is sensitive to different factors of the setup such as placement of the tracer release locations and distance from the landfill to the downwind measurements, which have not been thoroughly examined. In this study, numerical modeling is used as an alternative to field measurements to study the sensitivity of the tracer dilution method and provide estimates of measurement accuracy. Using topography and wind conditions for an actual landfill, a landfill emissions rate is prescribed in the model and compared against the emissions rate predicted by application of the tracer dilution method. Two different methane emissions scenarios are simulated: homogeneous emissions over the entire surface of the landfill, and heterogeneous emissions with a hot spot containing 80% of the total emissions where the daily cover area is located. Numerical modeling of the tracer dilution method is a useful tool for evaluating the method without having the expense and labor commitment of multiple field campaigns. Factors tested include number of tracers, distance between tracers, distance from landfill to transect path, and location of tracers with respect to the hot spot. Results show that location of the tracers relative to the hot spot of highest landfill emissions makes the largest difference in accuracy of the tracer dilution method.

Monitoring of Juvenile Subyearling Chinook Salmon Survival and Passage at John Day Dam, Summer 2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiland, Mark A.; Ploskey, Gene R.; Hughes, James S.

The purpose of this study was to evaluate dam passage survival of subyearling Chinook salmon (Oncorhynchus tshawytscha; CH0) at John Day Dam (JDA) during summer 2010. This study was conducted by researchers from the Pacific Northwest National Laboratory (PNNL) in collaboration with the Pacific States Marine Fisheries Commission (PSMFC) and the University of Washington (UW). The study was designed to estimate the effects of 30% and 40% spill treatment levels on single release survival rates of CH0 passing through two reaches: (1) the dam, and 40 km of tailwater, (2) the forebay, dam, and 40 km of tailwater. The studymore » also estimated additional passage performance measures which are stipulated in the Columbia Basin Fish Accords.« less

Simulations of a hypothetical temperature control structure at Detroit Dam on the North Santiam River, northwestern Oregon

USGS Publications Warehouse

Buccola, Norman L.; Stonewall, Adam J.; Rounds, Stewart A.

2015-01-01

Estimated egg-emergence days for endangered Upper Willamette River Chinook salmon (Oncorhynchus tshawytscha) and Upper Willamette River winter steelhead (Oncorhynchus mykiss) were assessed for all scenarios. Estimated spring Chinook fry emergence under SlidingWeir scenarios was 9 days later immediately downstream of Big Cliff Dam, and 4 days later at Greens Bridge compared with existing structural scenarios at Detroit Dam. Despite the inclusion of a hypothetical sliding weir at Detroit Dam, temperatures exceeded without-dams temperatures during November and December. These late-autumn exceedances likely represent the residual thermal effect of Detroit Lake operated to meet minimum dry-season release rates (supporting instream habitat and irrigation requirements) and lake levels specified by the current (2014) operating rules (supporting recreation and flood mitigation).

Experimental Evidence of Accelerated Seismic Release without Critical Failure in Acoustic Emissions of Compressed Nanoporous Materials

NASA Astrophysics Data System (ADS)

Baró, Jordi; Dahmen, Karin A.; Davidsen, Jörn; Planes, Antoni; Castillo, Pedro O.; Nataf, Guillaume F.; Salje, Ekhard K. H.; Vives, Eduard

2018-06-01

The total energy of acoustic emission (AE) events in externally stressed materials diverges when approaching macroscopic failure. Numerical and conceptual models explain this accelerated seismic release (ASR) as the approach to a critical point that coincides with ultimate failure. Here, we report ASR during soft uniaxial compression of three silica-based (SiO2 ) nanoporous materials. Instead of a singular critical point, the distribution of AE energies is stationary, and variations in the activity rate are sufficient to explain the presence of multiple periods of ASR leading to distinct brittle failure events. We propose that critical failure is suppressed in the AE statistics by mechanisms of transient hardening. Some of the critical exponents estimated from the experiments are compatible with mean field models, while others are still open to interpretation in terms of the solution of frictional and fracture avalanche models.

Secretory vesicles of immune cells contain only a limited number of interleukin 6 molecules.

PubMed

Verboogen, Daniëlle R J; Ter Beest, Martin; Honigmann, Alf; van den Bogaart, Geert

2018-05-01

Immune cells communicate by releasing large quantities of cytokines. Although the mechanisms of cytokine secretion are increasingly understood, quantitative knowledge of the number of cytokines per vesicle is still lacking. Here, we measured with quantitative microscopy the release rate of vesicles potentially carrying interleukin-6 (IL-6) in human dendritic cells. By comparing this to the total secreted IL-6, we estimate that secretory vesicles contain about 0.5-3 IL-6 molecules, but with a large spread among cells/donors. Moreover, IL-6 did not accumulate within most cells, indicating that synthesis and not trafficking is the bottleneck for IL-6 production. IL-6 accumulated in the Golgi apparatus only in ~ 10% of the cells. Understanding how immune cells produce cytokines is important for designing new immunomodulatory drugs. © 2018 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

High probability neurotransmitter release sites represent an energy efficient design

PubMed Central

Lu, Zhongmin; Chouhan, Amit K.; Borycz, Jolanta A.; Lu, Zhiyuan; Rossano, Adam J; Brain, Keith L.; Zhou, You; Meinertzhagen, Ian A.; Macleod, Gregory T.

2016-01-01

Nerve terminals contain multiple sites specialized for the release of neurotransmitters. Release usually occurs with low probability, a design thought to confer many advantages. High probability release sites are not uncommon but their advantages are not well understood. Here we test the hypothesis that high probability release sites represent an energy efficient design. We examined release site probabilities and energy efficiency at the terminals of two glutamatergic motor neurons synapsing on the same muscle fiber in Drosophila larvae. Through electrophysiological and ultrastructural measurements we calculated release site probabilities to differ considerably between terminals (0.33 vs. 0.11). We estimated the energy required to release and recycle glutamate from the same measurements. The energy required to remove calcium and sodium ions subsequent to nerve excitation was estimated through microfluorimetric and morphological measurements. We calculated energy efficiency as the number of glutamate molecules released per ATP molecule hydrolyzed, and high probability release site terminals were found to be more efficient (0.13 vs. 0.06). Our analytical model indicates that energy efficiency is optimal (~0.15) at high release site probabilities (~0.76). As limitations in energy supply constrain neural function, high probability release sites might ameliorate such constraints by demanding less energy. Energy efficiency can be viewed as one aspect of nerve terminal function, in balance with others, because high efficiency terminals depress significantly during episodic bursts of activity. PMID:27593375