The Effect of Growth Environment and Salinity on Lipid Production and Composition of Salicornia virginica

NASA Technical Reports Server (NTRS)

Bomani, Bilal Mark McDowell; Link, Dirk; Kail, Brian; Morreale, Bryan; Lee, Eric S.; Gigante, Bethany M.; Hendricks, Robert C.

2014-01-01

Finding a viable and sustainable source of renewable energy is a global task. Biofuels as a renewable energy source can potentially be a viable option for sustaining long-term energy needs. Biodiesel from halophytes shows great promise due to their ability to serve not only as a fuel source, but a food source as well. Halophytes are one of the few biomass plant species that can tolerate a wide range of saline conditions. We investigate the feasibility of using the halophyte, Salicornia virginica as a biofuel source by conducting a series of experiments utilizing various growth and salinity conditions. The goal is to determine if the saline content of Salicornia virginica in our indoor growth vs outdoor growth conditions has an influence on lipid recovery and total biomass composition. We focused on using standard lipid extraction protocols and characterization methods to evaluate twelve Salicornia virginica samples under six saline values ranging from freshwater to seawater and two growth conditions. The overall goal is to develop an optimal lipid extraction protocol for Salicornia virginica and potentially apply this protocol to halophytes in general.

Wind Power: A Turning Point. Worldwatch Paper 45.

ERIC Educational Resources Information Center

Flavin, Christopher

Recent studies have shown wind power to be an eminently practical and potentially substantial source of electricity and direct mechanical power. Wind machines range from simple water-pumping devices made of wood and cloth to large electricity producing turbines with fiberglass blades nearly 300 feet long. Wind is in effect a form of solar…

Long-Term Temporal Trends of Polychlorinated Biphenyls and Their Controlling Sources in China.

PubMed

Zhao, Shizhen; Breivik, Knut; Liu, Guorui; Zheng, Minghui; Jones, Kevin C; Sweetman, Andrew J

2017-03-07

Polychlorinated biphenyls (PCBs) are industrial organic contaminants identified as persistent, bioaccumulative, toxic (PBT), and subject to long-range transport (LRT) with global scale significance. This study focuses on a reconstruction and prediction for China of long-term emission trends of intentionally and unintentionally produced (UP) ∑ 7 PCBs (UP-PCBs, from the manufacture of steel, cement and sinter iron) and their re-emissions from secondary sources (e.g., soils and vegetation) using a dynamic fate model (BETR-Global). Contemporary emission estimates combined with predictions from the multimedia fate model suggest that primary sources still dominate, although unintentional sources are predicted to become a main contributor from 2035 for PCB-28. Imported e-waste is predicted to play an increasing role until 2020-2030 on a national scale due to the decline of intentionally produced (IP) emissions. Hypothetical emission scenarios suggest that China could become a potential source to neighboring regions with a net output of ∼0.4 t year -1 by around 2050. However, future emission scenarios and hence model results will be dictated by the efficiency of control measures.

Stable isotopes of lead and strontium as tracers of sources of airborne particulate matter in Kyrgyzstan

EPA Science Inventory

Central Asia is dominated by an arid climate and desert-like conditions, leading to the potential for long-range transport of desert dust within and out of the region. Of particular interest is the Aral Sea, which has receded in size largely due to water diversion. As a result, n...

Next-generation mid-infrared sources

NASA Astrophysics Data System (ADS)

Jung, D.; Bank, S.; Lee, M. L.; Wasserman, D.

2017-12-01

The mid-infrared (mid-IR) is a wavelength range with a variety of technologically vital applications in molecular sensing, security and defense, energy conservation, and potentially in free-space communication. The recent development and rapid commercialization of new coherent mid-infrared sources have spurred significant interest in the development of mid-infrared optical systems for the above applications. However, optical systems designers still do not have the extensive optical infrastructure available to them that exists at shorter wavelengths (for instance, in the visible and near-IR/telecom wavelengths). Even in the field of optoelectronic sources, which has largely driven the growing interest in the mid-infrared, the inherent limitations of state-of-the-art sources and the gaps in spectral coverage offer opportunities for the development of new classes of lasers, light emitting diodes and emitters for a range of potential applications. In this topical review, we will first present an overview of the current state-of-the-art mid-IR sources, in particular thermal emitters, which have long been utilized, and the relatively new quantum- and interband-cascade lasers, as well as the applications served by these sources. Subsequently, we will discuss potential mid-infrared applications and wavelength ranges which are poorly served by the current stable of mid-IR sources, with an emphasis on understanding the fundamental limitations of the current source technology. The bulk of the manuscript will then explore both past and recent developments in mid-infrared source technology, including narrow bandgap quantum well lasers, type-I and type-II quantum dot materials, type-II superlattices, highly mismatched alloys, lead-salts and transition-metal-doped II-VI materials. We will discuss both the advantages and limitations of each of the above material systems, as well as the potential new applications which they might serve. All in all, this topical review does not aim to provide a survey of the current state of the art for mid-IR sources, but instead looks primarily to provide a picture of potential next-generation optical and optoelectronic materials systems for mid-IR light generation.

A convenient and accurate wide-range parameter relationship between Buckingham and Morse potential energy functions

NASA Astrophysics Data System (ADS)

Lim, Teik-Cheng; Dawson, James Alexander

2018-05-01

This study explores the close-range, short-range and long-range relationships between the parameters of the Morse and Buckingham potential energy functions. The results show that the close-range and short-range relationships are valid for bond compression and for very small changes in bond length, respectively, while the long-range relationship is valid for bond stretching. A wide-range relationship is proposed to combine the comparative advantages of the close-range, short-range and long-range parameter relationships. The wide-range relationship is useful for replacing the close-range, short-range and long-range parameter relationships, thereby preventing the undesired effects of potential energy jumps resulting from functional switching between the close-range, short-range and long-range interaction energies.

Estimation of the contributions of long range transported aerosol in East Asia to carbonaceous aerosol and PM concentrations in Seoul, Korea using highly time resolved measurements: a PSCF model approach.

PubMed

Jeong, Ukkyo; Kim, Jhoon; Lee, Hanlim; Jung, Jinsang; Kim, Young J; Song, Chul H; Koo, Ja-Ho

2011-07-01

The contributions of long range transported aerosol in East Asia to carbonaceous aerosol and particulate matter (PM) concentrations in Seoul, Korea were estimated with potential source contribution function (PSCF) calculations. Carbonaceous aerosol (organic carbon (OC) and elemental carbon (EC)), PM(2.5), and PM(10) concentrations were measured from April 2007 to March 2008 in Seoul, Korea. The PSCF and concentration weighted trajectory (CWT) receptor models were used to identify the spatial source distributions of OC, EC, PM(2.5), and coarse particles. Heavily industrialized areas in Northeast China such as Harbin and Changchun and East China including the Pearl River Delta region, the Yangtze River Delta region, and the Beijing-Tianjin region were identified as high OC, EC and PM(2.5) source areas. The conditional PSCF analysis was introduced so as to distinguish the influence of aerosol transported from heavily polluted source areas on a receptor site from that transported from relatively clean areas. The source contributions estimated using the conditional PSCF analysis account for not only the aerosol concentrations of long range transported aerosols but also the number of transport days effective on the measurement site. Based on the proposed algorithm, the condition of airmass pathways was classified into two types: one condition where airmass passed over the source region (PS) and another condition where airmass did not pass over the source region (NPS). For most of the seasons during the measurement period, 249.5-366.2% higher OC, EC, PM(2.5), and coarse particle concentrations were observed at the measurement site under PS conditions than under NPS conditions. Seasonal variations in the concentrations of OC, EC, PM(2.5), and coarse particles under PS, NPS, and background aerosol conditions were quantified. The contributions of long range transported aerosols on the OC, EC, PM(2.5), and coarse particle concentrations during several Asian dust events were also estimated. We also investigated the performance of the PSCF results obtained from combining highly time resolved measurement data and backward trajectory calculations via comparison with those from data in low resolutions. Reduced tailing effects and the larger coverage over the area of interest were observed in the PSCF results obtained from using the highly time resolved data and trajectories.

Assessing the long-range transport of PAH to a sub-Arctic site using positive matrix factorization and potential source contribution function

NASA Astrophysics Data System (ADS)

Sofowote, Uwayemi M.; Hung, Hayley; Rastogi, Ankit K.; Westgate, John N.; Deluca, Patrick F.; Su, Yushan; McCarry, Brian E.

2011-02-01

Gas-phase and particle-phase atmospheric samples collected in a sparsely populated sub-Arctic environment in the Yukon Territory, Canada were analyzed for a wide range of organic pollutants including polycyclic aromatic hydrocarbons (PAH). Receptor modeling using positive matrix factorization (PMF) was applied to a PAH data set from samples collected between August 2007 and December 2008 to afford four factors. These factors were designated as fossil fuel combustion emissions, particle-phase wood combustion emissions, gas-phase wood combustion emissions, and unburned petroleum/petrogenic emissions. The multiple linear regression-derived average contributions of these factors to the total PAH concentrations were 14% for fossil fuel combustion, 6% for particle-phase wood combustion emissions, 46% for gas-phase wood combustion emissions and 34% for petrogenic emissions. When the total PAH concentrations (defined as the sum of twenty-two PAH) and the PMF-modeled PAH concentrations set were compared, the correlation was excellent ( R2 = 0.97). Ten-day back trajectories starting at four different heights were used in a potential source contribution function analysis (PSCF) to assess the potential source regions of these PAH factors. Mapping the computed PSCF values for the four PMF factors revealed different source regions in the northern hemisphere for each PMF factor. Atmospheric transport of PAH occurred from both relatively short and long distances with both continental (North American) and trans-oceanic (Asian) sources contributing significantly to the total PAH. This study provides evidence of the transport of fossil fuel and wood combustion emissions from Asia, continental North America and northern Europe to sub-Arctic Canada (and by extension to the Canadian Arctic) primarily during cooler (fall-winter) months. This study demonstrates for the first time that the combined PMF-PSCF methodology can be used to identify geographically-disperse PAH source contributors on a hemispherical scale.

Identification of source locations for atmospheric dry deposition of heavy metals during yellow-sand events in Seoul, Korea in 1998 using hybrid receptor models

NASA Astrophysics Data System (ADS)

Han, Young-Ji; Holsen, Thomas M.; Hopke, Philip K.; Cheong, Jang-Pyo; Kim, Ho; Yi, Seung-Muk

2004-10-01

Elemental dry deposition fluxes were measured using dry deposition plates from March to June 1998 in Seoul, Korea. During this spring sampling period several yellow-sand events characterized by long-range transport from China and Mongolia impacted the area. Understanding the impact of yellow-sand events on atmospheric dry deposition is critical to managing the heavy metal levels in the environment in Korea. In this study, the measured flux of a primarily crustal metal, Al and an anthropogenic metal, Pb was used with two hybrid receptor models, potential source contribution function (PSCF) and residence time weighted concentration (RTWC) for locating sources of heavy metals associated with atmospheric dry deposition fluxes during the yellow-sand events in Seoul, Korea. The PSCF using a criterion value of the 75th percentile of the measured dry deposition fluxes and RTWC results using the measured elemental dry deposition fluxes agreed well and consistently showed that there were large potential source areas in the Gobi Desert in China and Mongolia and industrial areas near Tianjin, Tangshan, and Shenyang in China. Major industrial areas of Shenyang, Fushun, and Anshan, the Central China loess plateau, the Gobi Desert, and the Alashan semi-desert in China were identified to be major source areas for the measured Pb flux in Seoul, Korea. For Al, the main industrial areas of Tangshan, Tianjin and Beijing, the Gobi Desert, the Alashan semi-desert, and the Central China loess plateau were found to be the major source areas. These results indicate that both anthropogenic sources such as industrial areas and natural sources such as deserts contribute to the high dry deposition fluxes of both Pb and Al in Seoul, Korea during yellow-sand events. RTWC resolved several high potential source areas. Modeling results indicated that the long-range transport of Al and Pb from China during yellow-sand events as well as non-yellow-sand spring daytimes increased atmospheric dry deposition of heavy metals in Korea.

Influence of regional biomass burning on the highly elevated organic carbon concentrations observed at Gosan, South Korea during a strong Asian dust period.

PubMed

Nguyen, Duc Luong; Kim, Jin Young; Ghim, Young Sung; Shim, Shang-Gyoo

2015-03-01

PM2.5 carbonaceous particles were measured at Gosan, South Korea during 29 March-11 April 2002 which includes a pollution period (30 March-01 April) when the highest concentrations of major anthropogenic species (nss-SO4 (2-), NO3 (-), and NH4 (+)) were observed and a strong Asian dust (AD) period (08-10 April) when the highest concentrations of mainly dust-originated trace elements (Al, Ca, Mg, and Fe) were seen. The concentrations of elemental carbon (EC) measured in the pollution period were higher than those measured in the strong AD period, whereas an inverse variation in the concentrations of organic carbon (OC) was observed. Based on the OC/EC ratios, the possible source that mainly contributed to the highly elevated OC concentrations measured in the strong AD period was biomass burning. The influence of the long-range transport of smoke plumes emitted from regional biomass burning sources was evaluated by using MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data for fire locations and the potential source contribution function analysis. The most potential source regions of biomass burning were the Primorsky and Amur regions in Far Eastern Russia and southeastern and southwestern Siberia, Russia. Further discussion on the source characteristics suggested that the high OC concentrations measured in the strong AD period were significantly affected by the smoldering phase of biomass burning. In addition to biomass burning, secondary OC (SOC) formed during atmospheric long-range transport should be also considered as an important source of OC concentration measured at Gosan. Although this study dealt with the episodic case of the concurrent increase of dust and biomass burning particles, understanding the characteristics of heterogeneous mixing aerosol is essential in assessing the radiative forcing of aerosol.

Understanding auditory distance estimation by humpback whales: a computational approach.

PubMed

Mercado, E; Green, S R; Schneider, J N

2008-02-01

Ranging, the ability to judge the distance to a sound source, depends on the presence of predictable patterns of attenuation. We measured long-range sound propagation in coastal waters to assess whether humpback whales might use frequency degradation cues to range singing whales. Two types of neural networks, a multi-layer and a single-layer perceptron, were trained to classify recorded sounds by distance traveled based on their frequency content. The multi-layer network successfully classified received sounds, demonstrating that the distorting effects of underwater propagation on frequency content provide sufficient cues to estimate source distance. Normalizing received sounds with respect to ambient noise levels increased the accuracy of distance estimates by single-layer perceptrons, indicating that familiarity with background noise can potentially improve a listening whale's ability to range. To assess whether frequency patterns predictive of source distance were likely to be perceived by whales, recordings were pre-processed using a computational model of the humpback whale's peripheral auditory system. Although signals processed with this model contained less information than the original recordings, neural networks trained with these physiologically based representations estimated source distance more accurately, suggesting that listening whales should be able to range singers using distance-dependent changes in frequency content.

Commercial objectives, technology transfer, and systems analysis for fusion power development

NASA Astrophysics Data System (ADS)

Dean, Stephen O.

1988-09-01

Fusion is an inexhaustible source of energy that has the potential for economic commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion energy development program is the generation of central station electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high energy neutrons suggests potentially unique applications. In addition, fusion R and D will lead to new products and new markets. Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other, are the two primary criteria for setting long range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R and D program toward practical applications. The transfer of fusion technology and skills from the national labs and universities to industry is the key to achieving the long range objective of commercial fusion applications.

Commercial objectives, technology transfer, and systems analysis for fusion power development

NASA Technical Reports Server (NTRS)

Dean, Stephen O.

1988-01-01

Fusion is an inexhaustible source of energy that has the potential for economic commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion energy development program is the generation of central station electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high energy neutrons suggests potentially unique applications. In addition, fusion R and D will lead to new products and new markets. Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other, are the two primary criteria for setting long range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R and D program toward practical applications. The transfer of fusion technology and skills from the national labs and universities to industry is the key to achieving the long range objective of commercial fusion applications.

Global and Regional Modeling of Long-Range Transport and Intercontinental Source-Receptor Linkages (presentation)

EPA Science Inventory

Because long-range transport has been shown to affect air quality in downwind continents, there is a growing realization that these effects may need to be considered in air quality management efforts by distinguishing between the contributions of local and regional emission sourc...

Parts on Demand: Evaluation of Approaches to Achieve Flexible Manufacturing Systems for Navy Parts on Demand. Volume 2. Appendices

DTIC Science & Technology

1984-02-01

of Cost Analysis Worksheets * POD Program-Economic Analysis & Methodology - Economic Evaluation Procedures for POD Investment Program - System...Approval Considerations - POD Investment Program - Potential Improvement Areas for POD - Example Cost Categories and Determinants Appendix E Long Range R&D...Funding Profiles * Investment Strategy for Integrated Circuits Diminishing Sources of Supply - Problem Scope - Approach - Alternatives - Proposed

Comparative assessment of the global fate and transport pathways of long-chain perfluorocarboxylic acids (PFCAs) and perfluorocarboxylates (PFCs) emitted from direct sources.

PubMed

Armitage, James M; Macleod, Matthew; Cousins, Ian T

2009-08-01

A global-scale multispecies mass balance model was used to simulate the long-term fate and transport of perfluorocarboxylic acids (PFCAs) with eight to thirteen carbons (C8-C13) and their conjugate bases, the perfluorocarboxylates (PFCs). The main purpose of this study was to assess the relative long-range transport (LRT) potential of each conjugate pair, collectively termed PFC(A)s, considering emissions from direct sources (i.e., manufacturing and use) only. Overall LRT potential (atmospheric + oceanic) varied as a function of chain length and depended on assumptions regarding pKa and mode of entry. Atmospheric transport makes a relatively higher contribution to overall LRT potential for PFC(A)s with longer chain length, which reflects the increasing trend in the air-water partition coefficient (K(AW)) of the neutral PFCA species with chain length. Model scenarios using estimated direct emissions of the C8, C9, and C11 PFC(A)s indicate that the mass fluxes to the Arctic marine environment associated with oceanic transport are in excess of mass fluxes from indirect sources (i.e., atmospheric transport of precursor substances such as fluorotelomer alcohols and subsequent degradation to PFCAs). Modeled concentrations of C8 and C9 in the abiotic environment are broadly consistent with available monitoring data in surface ocean waters. Furthermore, the modeled concentration ratios of C8 to C9 are reconcilable with the homologue pattern frequently observed in biota, assuming a positive correlation between bioaccumulation potential and chain length. Modeled concentration ratios of C11 to C10 are more difficult to reconcile with monitoring data in both source and remote regions. Our model results for C11 and C10 therefore imply that either (i) indirect sources are dominant or (ii) estimates of direct emission are not accurate for these homologues.

In vivo cross-sectional imaging of the phonating larynx using long-range Doppler optical coherence tomography

NASA Astrophysics Data System (ADS)

Coughlan, Carolyn A.; Chou, Li-Dek; Jing, Joseph C.; Chen, Jason J.; Rangarajan, Swathi; Chang, Theodore H.; Sharma, Giriraj K.; Cho, Kyoungrai; Lee, Donghoon; Goddard, Julie A.; Chen, Zhongping; Wong, Brian J. F.

2016-03-01

Diagnosis and treatment of vocal fold lesions has been a long-evolving science for the otolaryngologist. Contemporary practice requires biopsy of a glottal lesion in the operating room under general anesthesia for diagnosis. Current in-office technology is limited to visualizing the surface of the vocal folds with fiber-optic or rigid endoscopy and using stroboscopic or high-speed video to infer information about submucosal processes. Previous efforts using optical coherence tomography (OCT) have been limited by small working distances and imaging ranges. Here we report the first full field, high-speed, and long-range OCT images of awake patients’ vocal folds as well as cross-sectional video and Doppler analysis of their vocal fold motions during phonation. These vertical-cavity surface-emitting laser source (VCSEL) OCT images offer depth resolved, high-resolution, high-speed, and panoramic images of both the true and false vocal folds. This technology has the potential to revolutionize in-office imaging of the larynx.

Dominant source of disorder in graphene: charged impurities or ripples?

NASA Astrophysics Data System (ADS)

Fan, Zheyong; Uppstu, Andreas; Harju, Ari

2017-06-01

Experimentally produced graphene sheets exhibit a wide range of mobility values. Both extrinsic charged impurities and intrinsic ripples (corrugations) have been suggested to induce long-range disorder in graphene and could be a candidate for the dominant source of disorder. Here, using large-scale molecular dynamics and quantum transport simulations, we find that the hopping disorder and the gauge and scalar potentials induced by the ripples are short-ranged, in strong contrast with predictions by continuous models, and the transport fingerprints of the ripple disorder are very different from those of charged impurities. We conclude that charged impurities are the dominant source of disorder in most graphene samples, whereas scattering by ripples is mainly relevant in the high carrier density limit of ultraclean graphene samples (with a charged impurity concentration less than about 10 ppm) at room and higher temperatures. Our finding is valuable to theoretical modelling of transport properties of not only graphene, but also other two-dimensional materials, as the thermal ripples are universal.

Towards a street-level pollen concentration and exposure forecast

NASA Astrophysics Data System (ADS)

van der Molen, Michiel; Krol, Maarten; van Vliet, Arnold; Heuvelink, Gerard

2015-04-01

Atmospheric pollen are an increasing source of nuisance for people in industrialised countries and are associated with significant cost of medication and sick leave. Citizen pollen warnings are often based on emission mapping based on local temperature sum approaches or on long-range atmospheric model approaches. In practise, locally observed pollen may originate from both local sources (plants in streets and gardens) and from long-range transport. We argue that making this distinction is relevant because the diurnal and spatial variation in pollen concentrations is much larger for pollen from local sources than for pollen from long-range transport due to boundary layer processes. This may have an important impact on exposure of citizens to pollen and on mitigation strategies. However, little is known about the partitioning of pollen into local and long-range origin categories. Our objective is to study how the concentrations of pollen from different sources vary temporally and spatially, and how the source region influences exposure and mitigation strategies. We built a Hay Fever Forecast system (HFF) based on WRF-chem, Allergieradar.nl, and geo-statistical downscaling techniques. HFF distinguishes between local (individual trees) and regional sources (based on tree distribution maps). We show first results on how the diurnal variation of pollen concentrations depends on source proximity. Ultimately, we will compare the model with local pollen counts, patient nuisance scores and medicine use.

Frequency multiplexed long range swept source optical coherence tomography

PubMed Central

Zurauskas, Mantas; Bradu, Adrian; Podoleanu, Adrian Gh.

2013-01-01

We present a novel swept source optical coherence tomography configuration, equipped with acousto-optic deflectors that can be used to simultaneously acquire multiple B-scans originating from different depths. The sensitivity range of the configuration is evaluated while acquiring five simultaneous B-scans. Then the configuration is employed to demonstrate long range B-scan imaging by combining two simultaneous B-scans from a mouse head sample. PMID:23760762

Investigation of mercury deposition and potential sources at six sites from the Pacific Coast to the Great Basin, USA.

PubMed

Wright, Genine; Gustin, Mae Sexauer; Weiss-Penzias, Peter; Miller, Matthieu B

2014-02-01

The Western Airborne Contaminants Assessment Project showed that USA National Parks had fish mercury (Hg) concentrations above threshold concentrations set for wildlife. Since significant areas of the Western USA are arid, we hypothesized that dry deposition would be important. The primary question was whether sources of Hg were local and thus, easily addressed, or regional (from within the United States), or global (long range transport), and more difficult to address. To investigate this, surrogate surfaces and passive samplers for the measurement of GOM deposition and concentration, respectively, were deployed from the coast of California to the eastern edge of Nevada. Meteorological data, back trajectory modeling, and ozone concentrations were applied to better understand potential sources of Hg. Lowest seasonal mean Hg deposition (0.2 to 0.4 ng m(-2)h(-1)) was observed at low elevation (<100 m) Pacific Coast sites. Highest values were recorded at Lick Observatory, a high elevation coastal site (1,279 m), and Great Basin National Park (2,062 m) in rural eastern Nevada (1.5 to 2.4 ng m(-2)h(-1)). Intermediate values were recorded in Yosemite and Sequoia National Parks (0.9 to 1.2 ng m(-2)h(-1)). Results indicate that local, regional and global sources of air pollution, specifically oxidants, are contributing to observed deposition. At Great Basin National Park air chemistry was influenced by regional urban and agricultural emissions and free troposphere inputs. Dry deposition contributed ~2 times less Hg than wet deposition at the coastal locations, but 3 to 4 times more at the higher elevation sites. Based on the spatial trends, oxidation in the marine boundary layer or ocean sources contributed ~0.4 ng m(-2)h(-1) at the coastal locations. Regional pollution and long range transport contributed 1 to 2 ng m(-2)h(-1) to other locations, and the source of Hg is global and as such, all sources are important to consider. © 2013.

Spatio-temporal reconstruction of brain dynamics from EEG with a Markov prior.

PubMed

Hansen, Sofie Therese; Hansen, Lars Kai

2017-03-01

Electroencephalography (EEG) can capture brain dynamics in high temporal resolution. By projecting the scalp EEG signal back to its origin in the brain also high spatial resolution can be achieved. Source localized EEG therefore has potential to be a very powerful tool for understanding the functional dynamics of the brain. Solving the inverse problem of EEG is however highly ill-posed as there are many more potential locations of the EEG generators than EEG measurement points. Several well-known properties of brain dynamics can be exploited to alleviate this problem. More short ranging connections exist in the brain than long ranging, arguing for spatially focal sources. Additionally, recent work (Delorme et al., 2012) argues that EEG can be decomposed into components having sparse source distributions. On the temporal side both short and long term stationarity of brain activation are seen. We summarize these insights in an inverse solver, the so-called "Variational Garrote" (Kappen and Gómez, 2013). Using a Markov prior we can incorporate flexible degrees of temporal stationarity. Through spatial basis functions spatially smooth distributions are obtained. Sparsity of these are inherent to the Variational Garrote solver. We name our method the MarkoVG and demonstrate its ability to adapt to the temporal smoothness and spatial sparsity in simulated EEG data. Finally a benchmark EEG dataset is used to demonstrate MarkoVG's ability to recover non-stationary brain dynamics. Copyright © 2016 Elsevier Inc. All rights reserved.

Decomposing the profile of PM in two low polluted German cities--mapping of air mass residence time, focusing on potential long range transport impacts.

PubMed

Dimitriou, Konstantinos; Kassomenos, Pavlos

2014-07-01

This paper aims to decompose the profile of particulates in Karlsruhe and Potsdam (Germany), focusing on the localization of PM potential transboundary sources. An air mass cluster analysis was implemented, followed by a study of air mass residence time on a grid of a 0.5° × 0.5° resolution. Particulate/gaseous daily air pollution and meteorological data were used to indicate PM local sources. Four Principal Component Analysis (PCA) components were produced: traffic, photochemical, industrial/domestic and particulate. PM2.5/PM10 ratio seasonal trends, indicated production of PMCOARSE (PM10-PM2.5) from secondary sources in Potsdam during warm period (WP). The residing areas of incoming slow moving air masses are potential transboundary PM sources. For Karlsruhe those areas were mainly around the city. An air mass residence time secondary peak was observed over Stuttgart. For Potsdam, areas with increased dwelling time of the arriving air parcels were detected particularly above E/SE Germany. Copyright © 2014 Elsevier Ltd. All rights reserved.

High-speed upper-airway imaging using full-range optical coherence tomography

NASA Astrophysics Data System (ADS)

Jing, Joseph; Zhang, Jun; Loy, Anthony Chin; Wong, Brian J. F.; Chen, Zhongping

2012-11-01

Obstruction in the upper airway can often cause reductions in breathing or gas exchange efficiency and lead to rest disorders such as sleep apnea. Imaging diagnosis of the obstruction region has been accomplished using computed tomography (CT) and magnetic resonance imaging (MRI). However CT requires the use of ionizing radiation, and MRI typically requires sedation of the patient to prevent motion artifacts. Long-range optical coherence tomography (OCT) has the potential to provide high-speed three-dimensional tomographic images with high resolution and without the use of ionizing radiation. In this paper, we present work on the development of a long-range OCT endoscopic probe with 1.2 mm OD and 20 mm working distance used in conjunction with a modified Fourier domain swept source OCT system to acquire structural and anatomical datasets of the human airway. Imaging from the bottom of the larynx to the end of the nasal cavity is completed within 40 s.

Evaluation of Long Duration Flight on Venus

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Colozza, Anthony J.

2006-01-01

An analysis was performed to evaluate the potential of utilizing either an airship or aircraft as a flight platform for long duration flight within the atmosphere of Venus. In order to achieve long-duration flight, the power system for the vehicle had to be capable of operating for extended periods of time. To accomplish these, two types of power systems were considered, a solar energy-based power system utilizing a photovoltaic array as the main power source and a radioisotope heat source power system utilizing a Stirling engine as the heat conversion device. Both types of vehicles and power systems were analyzed to determine their flight altitude range. This analysis was performed for a station-keeping mission where the vehicle had to maintain a flight over a location on the ground. This requires the vehicle to be capable of flying faster than the wind speed at a particular altitude. An analysis was also performed to evaluate the altitude range and maximum duration for a vehicle that was not required to maintain station over a specified location. The results of the analysis show that each type of flight vehicle and power system was capable of flight within certain portions of Venus s atmosphere. The aircraft, both solar and radioisotope power proved to be the most versatile and provided the greatest range of coverage both for station-keeping and non-station-keeping missions.

VOC source identification from personal and residential indoor, outdoor and workplace microenvironment samples in EXPOLIS-Helsinki, Finland

NASA Astrophysics Data System (ADS)

Edwards, Rufus D.; Jurvelin, J.; Koistinen, K.; Saarela, K.; Jantunen, M.

Principal component analyses (varimax rotation) were used to identify common sources of 30 target volatile organic compounds (VOCs) in residential outdoor, residential indoor and workplace microenvironment and personal 48-h exposure samples, as a component of the EXPOLIS-Helsinki study. Variability in VOC concentrations in residential outdoor microenvironments was dominated by compounds associated with long-range transport of pollutants, followed by traffic emissions, emissions from trees and product emissions. Variability in VOC concentrations in environmental tobacco smoke (ETS) free residential indoor environments was dominated by compounds associated with indoor cleaning products, followed by compounds associated with traffic emissions, long-range transport of pollutants and product emissions. Median indoor/outdoor ratios for compounds typically associated with traffic emissions and long-range transport of pollutants exceeded 1, in some cases quite considerably, indicating substantial indoor source contributions. Changes in the median indoor/outdoor ratios during different seasons reflected different seasonal ventilation patterns as increased ventilation led to dilution of those VOC compounds in the indoor environment that had indoor sources. Variability in workplace VOC concentrations was dominated by compounds associated with traffic emissions followed by product emissions, long-range transport and air fresheners. Variability in VOC concentrations in ETS free personal exposure samples was dominated by compounds associated with traffic emissions, followed by long-range transport, cleaning products and product emissions. VOC sources in personal exposure samples reflected the times spent in different microenvironments, and personal exposure samples were not adequately represented by any one microenvironment, demonstrating the need for personal exposure sampling.

The long distance transport of airborne Ambrosia pollen to the UK and the Netherlands from Central and south Europe

NASA Astrophysics Data System (ADS)

de Weger, Letty A.; Pashley, Catherine H.; Šikoparija, Branko; Skjøth, Carsten A.; Kasprzyk, Idalia; Grewling, Łukasz; Thibaudon, Michel; Magyar, Donat; Smith, Matt

2016-12-01

The invasive alien species Ambrosia artemisiifolia (common or short ragweed) is increasing its range in Europe. In the UK and the Netherlands, airborne concentrations of Ambrosia pollen are usually low. However, more than 30 Ambrosia pollen grains per cubic metre of air (above the level capable to trigger allergic symptoms) were recorded in Leicester (UK) and Leiden (NL) on 4 and 5 September 2014. The aims of this study were to determine whether the highly allergenic Ambrosia pollen recorded during the episode could be the result of long distance transport, to identify the potential sources of these pollen grains and to describe the conditions that facilitated this possible long distance transport. Airborne Ambrosia pollen data were collected at 10 sites in Europe. Back trajectory and atmospheric dispersion calculations were performed using HYSPLIT_4. Back trajectories calculated at Leicester and Leiden show that higher altitude air masses (1500 m) originated from source areas on the Pannonian Plain and Ukraine. During the episode, air masses veered to the west and passed over the Rhône Valley. Dispersion calculations showed that the atmospheric conditions were suitable for Ambrosia pollen released from the Pannonian Plain and the Rhône Valley to reach the higher levels and enter the airstream moving to northwest Europe where they were deposited at ground level and recorded by monitoring sites. The study indicates that the Ambrosia pollen grains recorded during the episode in Leicester and Leiden were probably not produced by local sources but transported long distances from potential source regions in east Europe, i.e. the Pannonian Plain and Ukraine, as well as the Rhône Valley in France.

High average power, highly brilliant laser-produced plasma source for soft X-ray spectroscopy.

PubMed

Mantouvalou, Ioanna; Witte, Katharina; Grötzsch, Daniel; Neitzel, Michael; Günther, Sabrina; Baumann, Jonas; Jung, Robert; Stiel, Holger; Kanngiesser, Birgit; Sandner, Wolfgang

2015-03-01

In this work, a novel laser-produced plasma source is presented which delivers pulsed broadband soft X-radiation in the range between 100 and 1200 eV. The source was designed in view of long operating hours, high stability, and cost effectiveness. It relies on a rotating and translating metal target and achieves high stability through an on-line monitoring device using a four quadrant extreme ultraviolet diode in a pinhole camera arrangement. The source can be operated with three different laser pulse durations and various target materials and is equipped with two beamlines for simultaneous experiments. Characterization measurements are presented with special emphasis on the source position and emission stability of the source. As a first application, a near edge X-ray absorption fine structure measurement on a thin polyimide foil shows the potential of the source for soft X-ray spectroscopy.

Ultrahigh-brightness, spectrally-flat, short-wave infrared supercontinuum source for long-range atmospheric applications.

PubMed

Yin, Ke; Zhu, Rongzhen; Zhang, Bin; Jiang, Tian; Chen, Shengping; Hou, Jing

2016-09-05

Fiber based supercontinuum (SC) sources with output spectra covering the infrared atmospheric window are very useful in long-range atmospheric applications. It is proven that silica fibers can support the generation of broadband SC sources ranging from the visible to the short-wave infrared region. In this paper, we present the generation of an ultrahigh-brightness spectrally-flat 2-2.5 μm SC source in a cladding pumped thulium-doped fiber amplifier (TDFA) numerically and experimentally. The underlying physical mechanisms behind the SC generation process are investigated firstly with a numerical model which includes the fiber gain and loss, the dispersive and nonlinear effects. Simulation results show that abundant soliton pulses are generated in the TDFA, and they are shifted towards the long wavelength side very quickly with the nonlinearity of Raman soliton self-frequency shift (SSFS), and eventually the Raman SSFS process is halted due to the silica fiber's infrared loss. A spectrally-flat 2-2.5 μm SC source could be generated as the result of the spectral superposition of these abundant soliton pulses. These simulation results correspond qualitatively well to the following experimental results. Then, in the experiment, a cladding pumped large-mode-area TDFA is built for pursuing a high-power 2-2.5 μm SC source. By enhancing the pump strength, the output SC spectrum broadens to the long wavelength side gradually. At the highest pump power, the obtained SC source has a maximum average power of 203.4 W with a power conversion efficiency of 38.7%. It has a 3 dB spectral bandwidth of 545 nm ranging from 1990 to 2535 nm, indicating a power spectral density in excess of 370 mW/nm. Meanwhile, the output SC source has a good beam profile. This SC source, to the best of our knowledge, is the brightest spectrally-flat 2-2.5 μm light source ever reported. It will be highly desirable in a lot of long-range atmospheric applications, such as broad-spectrum LIDAR, free space communication and hyper-spectral imaging.

Monitoring of persistent organic pollutants in Africa. Part 2: design of a network to monitor the continental and intercontinental background.

PubMed

Lammel, G; Dobrovolný, P; Dvorská, A; Chromá, K; Brázdil, R; Holoubek, I; Hosek, J

2009-11-01

A network for the study of long-term trends of the continental background in Africa and the intercontinental background of persistent organic pollutants as resulting from long-range transport of contaminants from European, South Asian, and other potential source regions, as well as by watching supposedly pristine regions, i.e. the Southern Ocean and Antarctica is designed. The results of a pilot phase sampling programme in 2008 and meteorological and climatological information from the period 1961-2007 was used to apply objective criteria for the selection of stations for the monitoring network: out the original 26 stations six have been rejected because of suggested strong local sources of POPs and three others because of local meteorological effects, which may prevent part of the time long-range transported air to reach the sampling site. Representativeness of the meteorological patterns during the pilot phase with respect to climatology was assessed by comparison of the more local airflow situation as given by climatological vs. observed wind roses and by comparison of backward trajectories with the climatological wind (NCEP/NCAR re-analyses). With minor exceptions advection to nine inspected stations was typical for present-day climate during the pilot phase, 2008. Six to nine stations would cover satisfyingly large and densely populated regions of North-eastern, West and East Africa and its neighbouring seas, the Mediterranean, Northern and Equatorial Atlantic Ocean, the Western Indian Ocean and the Southern Ocean. Among the more densely populated areas Southern Cameroon, parts of the Abessinian plateau and most of the Great Lakes area would not be covered. The potential of the network is not hampered by on-going long-term changes of the advection to the selected stations, as these do hardly affect the coverage of target areas.

Use of Very Long Baseline Array Interferometric Data for Spacecraft Navigation

NASA Technical Reports Server (NTRS)

Martin-Mur, Tomas J.; Antreasian, P.; Border, J.; Benson, J.; Dhawan, V.; Fomalont, E.; Graat, E.; Jacobson, R.; Lanyi, G.; McElrath, T.;

Density of states and magnetotransport in Weyl semimetals with long-range disorder

NASA Astrophysics Data System (ADS)

Pesin, D. A.; Mishchenko, E. G.; Levchenko, A.

2015-11-01

We study the density of states and magnetotransport properties of disordered Weyl semimetals, focusing on the case of a strong long-range disorder. To calculate the disorder-averaged density of states close to nodal points, we treat exactly the long-range random potential fluctuations produced by charged impurities, while the short-range component of disorder potential is included systematically and controllably with the help of a diagram technique. We find that, for energies close to the degeneracy point, long-range potential fluctuations lead to a finite density of states. In the context of transport, we discuss that a self-consistent theory of screening in magnetic field may conceivably lead to nonmonotonic low-field magnetoresistance.

Long-range multiplicity correlations in proton-proton collisions

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

Bzdak, Adam

The forward-backward long-range multiplicity correlations in proton-proton collisions are investigated in the model with two independent sources of particles: one left- and one right-moving wounded nucleon. A good agreement with the UA5 Collaboration proton-antiproton data at the c.m. energy of 200 GeV is observed. For comparison the model with only one source of particles is also discussed.

Chemical and geochemical composition of spring-summer Arctic aerosol collected at Ny Alesund, Svalbard Islands.

NASA Astrophysics Data System (ADS)

Udisti, Roberto; Becagli, Silvia; Caiazzo, Laura; Cappelletti, David; Giardi, Fabio; Grotti, Marco; Lucarelli, Franco; Moroni, Beatrice; Nava, Silvia; Severi, Mirko; Traversi, Rita

2017-04-01

Since March 2010, spring-summer (usually March - September) campaigns were continuously carried out at the Italian Gruvebadet Observatory, Ny Alesund, Svalbard Island. Aerosol was sampled by PM10 (daily) and 4-stage (4-day resolution) collector devices and size distribution was evaluated at 10 min resolution in the range 10 nm - 20 um (106 size classes by a TSI SMPS-APS integrated system). Six-year (2010-2015) PM10 and size-segregated (>10, 10-2.5, 2.5-1, < 1 um) filters were analyzed for ion composition (inorganic anions and cations, and selected organic anions by Ion Chromatography), metal content (major and trace metals, including Rare Earth Elements - REEs, by PIXE and ICP-MS), Pb isotopic composition (by ICP-MS) and Elemental and Organic Carbon (EC-OC) concentrations. The data set was elaborated by multi-parametric statistical analysis (Positive Matrix Factorization - PMF), in order to identifying and quantifying the contribution of the main anthropic and natural aerosol sources. Particular attention was spent in evaluating the anthropic contribution of nss-sulphate, nitrate, EC and heavy metals during the Arctic Haze in spring. The isotopic composition of Pb was used in identifying the source areas (North America, Greenland, North Europe, Siberia, Iceland) of anthropic emissions as a function of seasonality (different atmospheric circulation pathway). Crustal metals and, especially, REEs anomalies (with respect to the Chondrite-normalized profile) allowed characterizing the dust emissions from their Potential Source Areas (PSA). Biogenic markers (especially methane sulfonic acid - MSA - and bio-nss-sulphate) was used to obtain relevant information about the relationship between marine biogenic activity (primary productivity) and sea ice coverage and atmospheric conditions (irradiance, temperature, circulation pathways). The seasonal pattern of the nitrate deposition was also investigated. Chemical and geochemical measurements were compared with high-resolution size distribution and back-trajectory cluster analysis in order to understand the seasonal pattern of the contributions of long-range transport (particles distributed in the accumulation mode, especially in spring) as well as the occurrence of nucleation events (in the nano-metric range, especially in late spring-summer). Bibliography R. Udisti et al., "Sulfate source apportionment in the Ny-Alesund (Svalbard Islands) Arctic aerosol". Rend. Fis. Acc. Lincei, 2016, 27, S85-S94. doi: 10.1007/s12210-016-0517-7. B. Moroni et al., "Local vs. long range sources of aerosol particles upon Ny-Alesund (Svalbard Islands): mineral chemistry and geochemical records". Rend. Fis. Acc. Lincei, 2016, 27, S115-S127. DOI 10.1007/s12210-016-0533-7. S. Becagli et al., "Relationships linking prymary production, sea ice melting, and biogenic aerosol in the Arctic". Atmos. Environ., 2016, 136, 1-15. http://dx.doi.org/10.1016/j.atmosenv.2016.04.002. A. Bazzano et al., "Long-range transport of atmospheric lead reaching Ny Alesund: inter-annual and seasonal variations of potential source areas". Atmos. Environ., 2016, 139, 11-19. http://dx.doi.org/10.1016/j.atmosenv.2016.05.026.

Sweet potato growth parameters, yield components and nutritive value for CELSS applications

NASA Technical Reports Server (NTRS)

Loretan, P. A.; Bonsi, C. K.; Hill, W. A.; Ogbuehi, C. R.; Mortley, D. G.

1989-01-01

Sweet potatoes have been grown hydroponically using the nutrient film technique (NFT) to provide a potential food source for long-term manned space missions. Experiments in both sand and NFT cultivars have produced up to 1790 g/plant of fresh storage root with an edible biomass index ranging from 60-89 percent and edible biomass linear growth rates of 39-66 g/sq m day in 105 to 130 days. Experiments with different cultivars, nutrient solution compositions, application rates, air and root temperatures, photoperiods, and light intensities indicate good potential for sweet potatoes in CELSS.

High thresholds for avoidance of sonar by free-ranging long-finned pilot whales (Globicephala melas).

PubMed

Antunes, R; Kvadsheim, P H; Lam, F P A; Tyack, P L; Thomas, L; Wensveen, P J; Miller, P J O

2014-06-15

The potential effects of exposing marine mammals to military sonar is a current concern. Dose-response relationships are useful for predicting potential environmental impacts of specific operations. To reveal behavioral response thresholds of exposure to sonar, we conducted 18 exposure/control approaches to 6 long-finned pilot whales. Source level and proximity of sonar transmitting one of two frequency bands (1-2 kHz and 6-7 kHz) were increased during exposure sessions. The 2-dimensional movement tracks were analyzed using a changepoint method to identify the avoidance response thresholds which were used to estimate dose-response relationships. No support for an effect of sonar frequency or previous exposures on the probability of response was found. Estimated response thresholds at which 50% of population show avoidance (SPLmax=170 dB re 1 μPa, SELcum=173 dB re 1 μPa(2) s) were higher than previously found for other cetaceans. The US Navy currently uses a generic dose-response relationship to predict the responses of cetaceans to naval active sonar, which has been found to underestimate behavioural impacts on killer whales and beaked whales. The navy curve appears to match more closely our results with long-finned pilot whales, though it might underestimate the probability of avoidance for pilot-whales at long distances from sonar sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cost of heat from a seasonal source

NASA Astrophysics Data System (ADS)

Reilly, R. W.; Brown, D. R.; Huber, H. D.

Results are reported of an investigation to estimate the cost of aquifer thermal energy storage (ATES) from a seasonal heat source. The cost of supplying energy (hot water) from an ATES system is estimated. Three types of loads are investigated: point demands, residential developments, and a multidistrict city. Several technical and economic factors are found to control the economic performance of an ATES system. Costs are found to be prohibitive for systems of small size, long transmission distances, and employing expensive purchased thermal energy. ATES is found to be cost-competitive with oil-fired and electric hot water delivery systems under a broad range of potential situations.

Comparative evaluation of solar, fission, fusion, and fossil energy resources, part 3

NASA Technical Reports Server (NTRS)

Clement, J. D.; Reupke, W. A.

1974-01-01

The role of nuclear fission reactors in becoming an important power source in the world is discussed. The supply of fissile nuclear fuel will be severely depleted by the year 2000. With breeder reactors the world supply of uranium could last thousands of years. However, breeder reactors have problems of a large radioactive inventory and an accident potential which could present an unacceptable hazard. Although breeder reactors afford a possible solution to the energy shortage, their ultimate role will depend on demonstrated safety and acceptable risks and environmental effects. Fusion power would also be a long range, essentially permanent, solution to the world's energy problem. Fusion appears to compare favorably with breeders in safety and environmental effects. Research comparing a controlled fusion reactor with the breeder reactor in solving our long range energy needs is discussed.

Assessment of secondary sources of Persistent Organic Pollutants in the Arctic

NASA Astrophysics Data System (ADS)

Pisso, Ignacio; Eckhardt, Sabine; Breivik, Knut

2014-05-01

Persistent organic pollutants (POPs) including highly toxic pesticides and other chemicals accumulate in living tissues and magnify in food chains. POPs are subject to long-range transport and hence represent a serious public health issue even in regions where their production is regulated. Rational control strategies require an understanding of the overall relationship between environmental emissions of contaminants and environmental / human exposure. In this study, we assess the relationships between environmental emissions and potential human exposure of organic contaminants with emphasis on long-range atmospheric transport. We investigate whether atmospheric levels of POPs measured at Zeppelin observatory in Svalbard since the early '90s are controlled by primary or secondary emissions. We present statistical indications that the measurements are affected by secondary ocean emissions and discuss the applicability of different inverse modeling approaches.

Bottom Interaction in Long Range Acoustic Propagation

DTIC Science & Technology

2006-09-30

Pacific Ocean utilizing controlled sources and vertical and horizontal receiver arrays . Broadband sources are considered with typical center...The LOAPEX (Long-range Ocean Acoustic Propagation Experiment) vertical line arrays (VLA) are described on page 1 of the LOAPEX cruise report: " The...hydrophone arrays on the two combined VLAs covered most of the 5-km water column. We refer to one of the VLAs as the deep VLA (DVLA), located at

Chirality and gravitational parity violation.

PubMed

Bargueño, Pedro

2015-06-01

In this review, parity-violating gravitational potentials are presented as possible sources of both true and false chirality. In particular, whereas phenomenological long-range spin-dependent gravitational potentials contain both truly and falsely chiral terms, it is shown that there are models that extend general relativity including also coupling of fermionic degrees of freedom to gravity in the presence of torsion, which give place to short-range truly chiral interactions similar to that usually considered in molecular physics. Physical mechanisms which give place to gravitational parity violation together with the expected size of the effects and their experimental constraints are discussed. Finally, the possible role of parity-violating gravity in the origin of homochirality and a road map for future research works in quantum chemistry is presented. © 2015 Wiley Periodicals, Inc.

CCN and IN concentration measurements during the Antarctic Circumnavigation Expedition

NASA Astrophysics Data System (ADS)

Stratmann, F.; Henning, S.; Löffler, M.; Welti, A.; Hartmann, M.; Wernli, H.; Baccarini, A.; Schmale, J.

2017-12-01

Cloud condensation nuclei (CCN) and ice nuclei (IN) concentrations measured during the Antarctic Circumnavigation Expedition (ACE) within the Study of Preindustrial-like Aerosol-Climate Effects (SPACE) are presented. The measurements give a circumpolar transect through the Sub Antarctic Ocean, where existing measurements are scarce. ACE took place during the austral summer 2016/17 and included exploration of different environments from pristine open Ocean to Antarctic islands and the southernmost ports of the 3 surrounding continents. CCN concentrations are measured over the entire range of expected in-cloud supersaturations from 0.1 to 1% using a CCNc instrument from DMT. IN concentrations are determined from filter samples at water saturated conditions from -5°C to -25°C, covering common temperatures of mixed-phase cloud glaciation. The sensitivity of measured IN and CCN concentrations to meteorological parameters, activity of marine biology and location is assessed to gain insight into potential sources of CCN and IN. Back trajectory modelling is used to allocate regional variations to aerosol sources originating in the marine boundary layer or long-range transport. The gained datasets constrain CCN and IN concentrations in the marine boundary layer along the cruise track. The comprehensive set of parallel measured parameters during ACE allow to evaluate contributions of local ocean-surface sources versus long-range transport to Sub-Antarctic CCN and IN. The measurements can be used as input to climate models, e.g. pristine Sub Antarctic conditions can provide an approximation for a pre-industrial environment.

Transport and fate of gaseous pollutants associated with the National Energy Program.

PubMed Central

Altshuller, A P; Johnson, W B; Nader, J S; Niemann, B L; Turner, D B; Wilson, W E; D'Alessio, G

1980-01-01

The experimental evidence related to the long-range transport and transformations of sulfates has been critically reviewed. It has been concluded that sulfate emissions from various sources can be superimposed on each other during long-range transport to create episodes far from the contributing sources. Sulfates are important contributors to degrading visibility through the United States including relatively pristine areas in the western United States. Acid sulfate components, along with nitric acid, may increase the problem of acidity in precipitation on soils, vegetation, and lakes in certain areas of the eastern United States. Improvements in monitoring of these pollutants are required to follow changes in air quality caused by long-range transport. PMID:7428742

Design of a Long Endurance Titan VTOL Vehicle

NASA Technical Reports Server (NTRS)

Prakash, Ravi; Braun, Robert D.; Colby, Luke S.; Francis, Scott R.; Guenduez, Mustafa E.; Flaherty, Kevin W.; Lafleur, Jarret M.; Wright, Henry S.

2006-01-01

Saturn s moon Titan promises insight into many key scientific questions, many of which can be investigated only by in situ exploration of the surface and atmosphere of the moon. This research presents a vertical takeoff and landing (VTOL) vehicle designed to conduct a scientific investigation of Titan s atmosphere, clouds, haze, surface, and any possible oceans. In this investigation, multiple options for vertical takeoff and horizontal mobility were considered. A helicopter was baselined because of its many advantages over other types of vehicles, namely access to hazardous terrain and the ability to perform low speed aerial surveys. Using a nuclear power source and the atmosphere of Titan, a turbo expander cycle produces the 1.9 kW required by the vehicle for flight and operations, allowing it to sustain a long range, long duration mission that could traverse the majority of Titan. Such a power source could increase the lifespan and quality of science for planetary aerial flight to an extent that the limiting factor for the mission life is not available power but the life of the mechanical parts. Therefore, the mission could potentially last for years. This design is the first to investigate the implications of this potentially revolutionary technology on a Titan aerial vehicle.

Long axial imaging range using conventional swept source lasers in optical coherence tomography via re-circulation loops

NASA Astrophysics Data System (ADS)

Bradu, Adrian; Jackson, David A.; Podoleanu, Adrian

2018-03-01

Typically, swept source optical coherence tomography (SS-OCT) imaging instruments are capable of a longer axial range than their camera based (CB) counterpart. However, there are still various applications that would take advantage for an extended axial range. In this paper, we propose an interferometer configuration that can be used to extend the axial range of the OCT instruments equipped with conventional swept-source lasers up to a few cm. In this configuration, the two arms of the interferometer are equipped with adjustable optical path length rings. The use of semiconductor optical amplifiers in the two rings allows for compensating optical losses hence, multiple paths depth reflectivity profiles (Ascans) can be combined axially. In this way, extremely long overall axial ranges are possible. The use of the recirculation loops produces an effect equivalent to that of extending the coherence length of the swept source laser. Using this approach, the achievable axial imaging range in SS-OCT can reach values well beyond the limit imposed by the coherence length of the laser, to exceed in principle many centimeters. In the present work, we demonstrate axial ranges exceeding 4 cm using a commercial swept source laser and reaching 6 cm using an "in-house" swept source laser. When used in a conventional set-up alone, both these lasers can provide less than a few mm axial range.

Vaccine financing in Nigeria: are we making progress towards self-financing/sustenance?

PubMed

Faniyan, Olumide; Opara, Chidiabere; Oyinade, Akinyede; Botchway, Pamela; Soyemi, Kenneth

2017-01-01

Nigeria has an estimated population of 186 million with 23% of eligible children aged 12-23 months fully immunized. Government spending on routine immunization per surviving infant has declined since 2006 meaning the immunization budget needs to improve. By 2020, Nigeria will be ineligible for additional Global Alliance for Vaccination and Immunization (Gavi) grants and will be facing an annual vaccine bill of around US$426.3m. There are several potential revenue sources that could be utilized to fill the potential funding gap, these are however subject to timely legislation and appropriation of funds by the legislative body. Innovative funding sources that should be considered include tiered levies on tele-communications, airline, hotel, alcohol, tobacco, sugar beverage taxes, lottery sales, crowd-sourcing, optimized federal state co-financing etc. To demonstrate monthly income that will be derived from a single tax revenue source, we modelled using Monte Carlo simulation trials the Communication Service Tax that is being introduced by the National Assembly. We used number of active telephone subscribers, penetration ratio, monthly charges, and percent of immunization levy as model scenario inputs and dollars generated monthly as output. The simulation generated a modest mean (SD) monthly amount of $3,649,289.38 ($1,789,651); 88% certainty range $1,282,719.90 to $7,450,906.26. The entire range for the simulation was $528,903.26 to $7,966,287.26 with a standard error of mean of $17,896.52. Sensitivity analysis revealed that percentage of immunization levy contributed 97.9 percent of the variance in the model, number of active subscribers and charges per month contributed 1.5%, and 0.6% respectively. Our modest simulation analysis demonstrated the potential to raise revenue from one possible tax source; when combined, the revenue sources will potentially surpass Nigeria's long-term financing needs. The ROI of vaccine should supersede all other considerations and prompt urgent activities to cover the impending finance coverage gap.

Vaccine financing in Nigeria: are we making progress towards self-financing/sustenance?

PubMed Central

Faniyan, Olumide; Opara, Chidiabere; Oyinade, Akinyede; Botchway, Pamela; Soyemi, Kenneth

2017-01-01

Nigeria has an estimated population of 186 million with 23% of eligible children aged 12-23 months fully immunized. Government spending on routine immunization per surviving infant has declined since 2006 meaning the immunization budget needs to improve. By 2020, Nigeria will be ineligible for additional Global Alliance for Vaccination and Immunization (Gavi) grants and will be facing an annual vaccine bill of around US$426.3m. There are several potential revenue sources that could be utilized to fill the potential funding gap, these are however subject to timely legislation and appropriation of funds by the legislative body. Innovative funding sources that should be considered include tiered levies on tele-communications, airline, hotel, alcohol, tobacco, sugar beverage taxes, lottery sales, crowd-sourcing, optimized federal state co-financing etc. To demonstrate monthly income that will be derived from a single tax revenue source, we modelled using Monte Carlo simulation trials the Communication Service Tax that is being introduced by the National Assembly. We used number of active telephone subscribers, penetration ratio, monthly charges, and percent of immunization levy as model scenario inputs and dollars generated monthly as output. The simulation generated a modest mean (SD) monthly amount of $3,649,289.38 ($1,789,651); 88% certainty range $1,282,719.90 to $7,450,906.26. The entire range for the simulation was $528,903.26 to $7,966,287.26 with a standard error of mean of $17,896.52. Sensitivity analysis revealed that percentage of immunization levy contributed 97.9 percent of the variance in the model, number of active subscribers and charges per month contributed 1.5%, and 0.6% respectively. Our modest simulation analysis demonstrated the potential to raise revenue from one possible tax source; when combined, the revenue sources will potentially surpass Nigeria’s long-term financing needs. The ROI of vaccine should supersede all other considerations and prompt urgent activities to cover the impending finance coverage gap. PMID:29296144

The innovative concept of three-dimensional hybrid receptor modeling

NASA Astrophysics Data System (ADS)

Stojić, A.; Stanišić Stojić, S.

2017-09-01

The aim of this study was to improve the current understanding of air pollution transport processes at regional and long-range scale. For this purpose, three-dimensional (3D) potential source contribution function and concentration weighted trajectory models, as well as new hybrid receptor model, concentration weighted boundary layer (CWBL), which uses a two-dimensional grid and a planetary boundary layer height as a frame of reference, are presented. The refined approach to hybrid receptor modeling has two advantages. At first, it considers whether each trajectory endpoint meets the inclusion criteria based on planetary boundary layer height, which is expected to provide a more realistic representation of the spatial distribution of emission sources and pollutant transport pathways. Secondly, it includes pollutant time series preprocessing to make hybrid receptor models more applicable for suburban and urban locations. The 3D hybrid receptor models presented herein are designed to identify altitude distribution of potential sources, whereas CWBL can be used for analyzing the vertical distribution of pollutant concentrations along the transport pathway.

Laser vibration sensing at Fraunhofer IOSB: review and applications

NASA Astrophysics Data System (ADS)

Lutzmann, Peter; Göhler, Benjamin; Hill, Chris A.; van Putten, Frank

2017-03-01

Laser vibrometry based on coherent detection allows noncontact measurements of small-amplitude vibration characteristics of objects. This technique, commonly using the Doppler effect, offers high potential for short-range civil applications and for medium- or long-range applications in defense and security. Most commercially available laser Doppler vibrometers are for short ranges (up to a few tens of meters) and use a single beam from a low-power HeNe laser source (λ=633 nm). Medium- or long-range applications need higher laser output power, and thus, appropriate vibrometers typically operate at 1.5, 2, or 10.6 μm to meet the laser safety regulations. Spatially resolved vibrational information can be obtained from an object by using scanning laser vibrometers. To reduce measuring time and to measure transient object movements and vibrational mode structures of objects, several approaches to multibeam laser Doppler vibrometry have been developed, and some of them are already commercially available for short ranges. We focus on applications in the field of defense and security, such as target classification and identification, including camouflaged or partly concealed targets, and the detection of buried land mines. Examples of civil medium-range applications are also given.

Development of benzene, toluene, ethylbenzene and xylenes certified gaseous reference materials

NASA Astrophysics Data System (ADS)

Brum, M. C.; Sobrinho, D. C. G.; Fagundes, F. A.; Oudwater, R. J.; Augusto, C. R.

2016-07-01

The work describes the production of certified gaseous reference materials of benzene, toluene, ethylbenzene and xylenes (BTEX) in nitrogen from the gravimetric production up to the long term stability tests followed by the certifying step. The uncertainty in the amount fractions of the compounds in these mixtures was approximately 4% (relative) for the range studied from 2 to 16 µmol/mol. Also the adsorption of the BTEX on the cylinder surface and the tubing were investigated as potential uncertainty source.

Momentum-space cluster dual-fermion method

NASA Astrophysics Data System (ADS)

Iskakov, Sergei; Terletska, Hanna; Gull, Emanuel

2018-03-01

Recent years have seen the development of two types of nonlocal extensions to the single-site dynamical mean field theory. On one hand, cluster approximations, such as the dynamical cluster approximation, recover short-range momentum-dependent correlations nonperturbatively. On the other hand, diagrammatic extensions, such as the dual-fermion theory, recover long-ranged corrections perturbatively. The correct treatment of both strong short-ranged and weak long-ranged correlations within the same framework is therefore expected to lead to a quick convergence of results, and offers the potential of obtaining smooth self-energies in nonperturbative regimes of phase space. In this paper, we present an exact cluster dual-fermion method based on an expansion around the dynamical cluster approximation. Unlike previous formulations, our method does not employ a coarse-graining approximation to the interaction, which we show to be the leading source of error at high temperature, and converges to the exact result independently of the size of the underlying cluster. We illustrate the power of the method with results for the second-order cluster dual-fermion approximation to the single-particle self-energies and double occupancies.

Intensity-modulated polarizabilities and magic trapping of alkali-metal and divalent atoms in infrared optical lattices

NASA Astrophysics Data System (ADS)

Topcu, Turker; Derevianko, Andrei

2014-05-01

Long range interactions between neutral Rydberg atoms has emerged as a potential means for implementing quantum logical gates. These experiments utilize hyperfine manifold of ground state atoms to act as a qubit basis, while exploiting the Rydberg blockade mechanism to mediate conditional quantum logic. The necessity for overcoming several sources of decoherence makes magic wavelength trapping in optical lattices an indispensable tool for gate experiments. The common wisdom is that atoms in Rydberg states see trapping potentials that are essentially that of a free electron, and can only be trapped at laser intensity minima. We show that although the polarizability of a Rydberg state is always negative, the optical potential can be both attractive or repulsive at long wavelengths (up to ~104 nm). This opens up the possibility of magic trapping Rydberg states with ground state atoms in optical lattices, thereby eliminating the necessity to turn off trapping fields during gate operations. Because the wavelengths are near the CO2 laser band, the photon scattering and the ensuing motional heating is also reduced compared to conventional traps near low lying resonances, alleviating an important source of decoherence. This work was supported by the National Science Foundation (NSF) Grant No. PHY-1212482.

Detection and Estimation of 2-D Distributions of Greenhouse Gas Source Concentrations and Emissions over Complex Urban Environments and Industrial Sites

NASA Astrophysics Data System (ADS)

Zaccheo, T. S.; Pernini, T.; Dobler, J. T.; Blume, N.; Braun, M.

2017-12-01

This work highlights the use of the greenhouse-gas laser imaging tomography experiment (GreenLITETM) data in conjunction with a sparse tomography approach to identify and quantify both urban and industrial sources of CO2 and CH4. The GreenLITETM system provides a user-defined set of time-sequenced intersecting chords or integrated column measurements at a fixed height through a quasi-horizontal plane of interest. This plane, with unobstructed views along the lines of sight, may range from complex industrial facilities to a small city scale or urban sector. The continuous time phased absorption measurements are converted to column concentrations and combined with a plume based model to estimate the 2-D distribution of gas concentration over extended areas ranging from 0.04-25 km2. Finally, these 2-D maps of concentration are combined with ancillary meteorological and atmospheric data to identify potential emission sources and provide first order estimates of their associated fluxes. In this presentation, we will provide a brief overview of the systems and results from both controlled release experiments and a long-term system deployment in Paris, FR. These results provide a quantitative assessment of the system's ability to detect and estimate CO2 and CH4 sources, and demonstrate its ability to perform long-term autonomous monitoring and quantification of either persistent or sporadic emissions that may have both health and safety as well as environmental impacts.

Single-particle characterization of the High Arctic summertime aerosol

NASA Astrophysics Data System (ADS)

Sierau, B.; Chang, R. Y.-W.; Leck, C.; Paatero, J.; Lohmann, U.

2014-01-01

Single-particle mass spectrometric measurements were carried out in the High Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS). The instrument deployed was an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) that provides information on the chemical composition of individual particles and their mixing state in real-time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 nm to 3000 nm in diameter showed mass spectrometric patterns indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the High Arctic. To assess the importance of long-range particle sources for aerosol-cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a~minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest a presence of a particle type of unknown composition and source. In general, the study suffered from low counting statistics due to the overall small number of particles found in this pristine environment, the small sizes of the prevailing aerosol below the detection limit of the ATOFMS and its low hit rate. To our knowledge, this study reports on the first in-situ single-particle mass spectrometric measurements in the marine boundary layer of the High-Arctic pack-ice region.

Single-particle characterization of the high-Arctic summertime aerosol

NASA Astrophysics Data System (ADS)

Sierau, B.; Chang, R. Y.-W.; Leck, C.; Paatero, J.; Lohmann, U.

2014-07-01

Single-particle mass-spectrometric measurements were carried out in the high Arctic north of 80° during summer 2008. The campaign took place onboard the icebreaker Oden and was part of the Arctic Summer Cloud Ocean Study (ASCOS). The instrument deployed was an aerosol time-of-flight mass spectrometer (ATOFMS) that provides information on the chemical composition of individual particles and their mixing state in real time. Aerosols were sampled in the marine boundary layer at stations in the open ocean, in the marginal ice zone, and in the pack ice region. The largest fraction of particles detected for subsequent analysis in the size range of the ATOFMS between approximately 200 and 3000 nm in diameter showed mass-spectrometric patterns, indicating an internal mixing state and a biomass burning and/or biofuel source. The majority of these particles were connected to an air mass layer of elevated particle concentration mixed into the surface mixed layer from the upper part of the marine boundary layer. The second largest fraction was represented by sea salt particles. The chemical analysis of the over-ice sea salt aerosol revealed tracer compounds that reflect chemical aging of the particles during their long-range advection from the marginal ice zone, or open waters south thereof prior to detection at the ship. From our findings we conclude that long-range transport of particles is one source of aerosols in the high Arctic. To assess the importance of long-range particle sources for aerosol-cloud interactions over the inner Arctic in comparison to local and regional biogenic primary aerosol sources, the chemical composition of the detected particles was analyzed for indicators of marine biological origin. Only a minor fraction showed chemical signatures of potentially ocean-derived primary particles of that kind. However, a chemical bias in the ATOFMS's detection capabilities observed during ASCOS might suggest the presence of a particle type of unknown composition and source. In general, the study suffered from low counting statistics due to the overall small number of particles found in this pristine environment, the small sizes of the prevailing aerosol below the detection limit of the ATOFMS, and its low hit rate. To our knowledge, this study reports on the first in situ single-particle mass-spectrometric measurements in the marine boundary layer of the high-Arctic pack ice region.

Atmospheric speciated mercury concentrations on an island between China and Korea: sources and transport pathways

NASA Astrophysics Data System (ADS)

Lee, G.-S.; Kim, P.-R.; Han, Y.-J.; Holsen, T. M.; Seo, Y.-S.; Yi, S.-M.

2015-11-01

As a global pollutant, mercury (Hg) is of particular concern in East Asia where anthropogenic emissions are the largest. In this study, speciated Hg concentrations were measured in the western most island in Korea, located between China and the Korean mainland to identify the importance of local, regional and distant Hg sources. Various tools including correlations with other pollutants, conditional probability function, and back-trajectory based analysis consistently indicated that Korean sources were important for gaseous oxidized mercury (GOM) whereas, for total gaseous mercury (TGM) and particulate bound mercury (PBM), long-range and regional transport were also important. A trajectory cluster based approach considering both Hg concentration and the fraction of time each cluster was impacting the site was developed to quantify the effect of Korean sources and out-of-Korean source. This analysis suggests that Korean sources contributed approximately 55 % of the GOM and PBM while there were approximately equal contributions from Korean and out-of-Korean sources for the TGM measured at the site. The ratio of GOM / PBM decreased when the site was impacted by long-range transport, suggesting that this ratio may be a useful tool for identifying the relative significance of local sources vs. long-range transport. The secondary formation of PBM through gas-particle partitioning with GOM was found to be important at low temperatures and high relative humidity.

Highly parallel demagnetization field calculation using the fast multipole method on tetrahedral meshes with continuous sources

NASA Astrophysics Data System (ADS)

Palmesi, P.; Exl, L.; Bruckner, F.; Abert, C.; Suess, D.

2017-11-01

The long-range magnetic field is the most time-consuming part in micromagnetic simulations. Computational improvements can relieve problems related to this bottleneck. This work presents an efficient implementation of the Fast Multipole Method [FMM] for the magnetic scalar potential as used in micromagnetics. The novelty lies in extending FMM to linearly magnetized tetrahedral sources making it interesting also for other areas of computational physics. We treat the near field directly and in use (exact) numerical integration on the multipole expansion in the far field. This approach tackles important issues like the vectorial and continuous nature of the magnetic field. By using FMM the calculations scale linearly in time and memory.

Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics.

PubMed

Quan, Wei; Hao, XiaoLei; Chen, YongJu; Yu, ShaoGang; Xu, SongPo; Wang, YanLan; Sun, RenPing; Lai, XuanYang; Wu, ChengYin; Gong, QiHuang; He, XianTu; Liu, XiaoJun; Chen, Jing

2016-06-03

In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.e., up to several hundreds atomic units) plays an important role in determining the photoelectron dynamics after the pulse ends.

Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics

PubMed Central

Quan, Wei; Hao, XiaoLei; Chen, YongJu; Yu, ShaoGang; Xu, SongPo; Wang, YanLan; Sun, RenPing; Lai, XuanYang; Wu, ChengYin; Gong, QiHuang; He, XianTu; Liu, XiaoJun; Chen, Jing

2016-01-01

In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.e., up to several hundreds atomic units) plays an important role in determining the photoelectron dynamics after the pulse ends. PMID:27256904

Ice nucleating particles in the high Arctic at the beginning of the melt season

NASA Astrophysics Data System (ADS)

Hartmann, M.; Gong, X.; Van Pinxteren, M.; Welti, A.; Zeppenfeld, S.; Herrmann, H.; Stratmann, F.

2017-12-01

Ice nucleating particles (INPs) initiate the ice crystal formation in persistent Arctic mixed-phase clouds and are important for the formation of precipitation, which affects the radiative properties of the Arctic pack ice as well as the radiative properties of clouds. Sources of Arctic INP have been suggested to be local emissions from the marine boundary and long-range transport. To what extent local marine sources contribute to the INP population or if the majority of INPs originate from long-range transport is not yet known. Ship-based INP measurements in the PASCAL framework are reported. The field campaign took place from May 24 to July 20 2017 around and north of Svalbard (up to 84°N, between 0° and 35°E) onboard the RV Polarstern. INP concentrations were determined applying in-situ measurements (DMT Spectrometer for Ice Nuclei, SPIN) and offline filter techniques (filter sampling on both quartz fiber and polycarbonate filters with subsequent analysis of filter pieces and water suspension from particles collected on filters by means of immersion freezing experiments on cold stage setups). Additionally the compartments sea-surface micro layer (SML), bulk sea water, snow, sea ice and fog water were sampled and their ice nucleation potential quantified, also utilizing cold stages. The measurements yield comprehensive picture of the spatial and temporal distribution of INPs around Svalbard for the different compartments. The dependence of the INP concentration on meteorological conditions (e.g. wind speed) and the geographical situation (sea ice cover, distance to the ice edge) are investigated. Potential sources of INP are identified by the comparison of INP concentrations in the compartments and by back trajectory analysis.

Moving house: long-term dynamics of corticosterone secretion are unaltered in translocated populations of a rare reptile (the tuatara, Sphenodon punctatus).

PubMed

Anderson, Lindsay E; Cree, Alison; Towns, David R; Nelson, Nicola J

2015-01-01

Translocations are an important conservation tool used to restore at-risk species to their historical range. Unavoidable procedures during translocations, such as habitat disturbance, capture, handling, processing, captivity, transport and release to a novel environment, have the potential to be stressful for most species. In this study, we examined acute and chronic stress (through the measurement of the glucocorticoid corticosterone) in a rare reptile (the tuatara, Sphenodon punctatus). We found that: (i) the acute corticosterone response remains elevated during the initial translocation process but is not amplified by cumulative stressors; and (ii) the long-term dynamics of corticosterone secretion are similar in translocated and source populations. Taken together, our results show that translocated tuatara are generally resistant to cumulative acute stressors and show no hormonal sign of chronic stress. Translocation efforts in tuatara afford the potential to reduce extinction risk and restore natural ecosystems.

Long-range and wide field of view optical coherence tomography for in vivo 3D imaging of large volume object based on akinetic programmable swept source.

PubMed

Song, Shaozhen; Xu, Jingjiang; Wang, Ruikang K

2016-11-01

Current optical coherence tomography (OCT) imaging suffers from short ranging distance and narrow imaging field of view (FOV). There is growing interest in searching for solutions to these limitations in order to expand further in vivo OCT applications. This paper describes a solution where we utilize an akinetic swept source for OCT implementation to enable ~10 cm ranging distance, associated with the use of a wide-angle camera lens in the sample arm to provide a FOV of ~20 x 20 cm 2 . The akinetic swept source operates at 1300 nm central wavelength with a bandwidth of 100 nm. We propose an adaptive calibration procedure to the programmable akinetic light source so that the sensitivity of the OCT system over ~10 cm ranging distance is substantially improved for imaging of large volume samples. We demonstrate the proposed swept source OCT system for in vivo imaging of entire human hands and faces with an unprecedented FOV (up to 400 cm 2 ). The capability of large-volume OCT imaging with ultra-long ranging and ultra-wide FOV is expected to bring new opportunities for in vivo biomedical applications.

Long-range and wide field of view optical coherence tomography for in vivo 3D imaging of large volume object based on akinetic programmable swept source

PubMed Central

Song, Shaozhen; Xu, Jingjiang; Wang, Ruikang K.

2016-01-01

Current optical coherence tomography (OCT) imaging suffers from short ranging distance and narrow imaging field of view (FOV). There is growing interest in searching for solutions to these limitations in order to expand further in vivo OCT applications. This paper describes a solution where we utilize an akinetic swept source for OCT implementation to enable ~10 cm ranging distance, associated with the use of a wide-angle camera lens in the sample arm to provide a FOV of ~20 x 20 cm2. The akinetic swept source operates at 1300 nm central wavelength with a bandwidth of 100 nm. We propose an adaptive calibration procedure to the programmable akinetic light source so that the sensitivity of the OCT system over ~10 cm ranging distance is substantially improved for imaging of large volume samples. We demonstrate the proposed swept source OCT system for in vivo imaging of entire human hands and faces with an unprecedented FOV (up to 400 cm2). The capability of large-volume OCT imaging with ultra-long ranging and ultra-wide FOV is expected to bring new opportunities for in vivo biomedical applications. PMID:27896012

Smart CMOS sensor for wideband laser threat detection

NASA Astrophysics Data System (ADS)

Schwarze, Craig R.; Sonkusale, Sameer

2015-09-01

The proliferation of lasers has led to their widespread use in applications ranging from short range standoff chemical detection to long range Lidar sensing and target designation operating across the UV to LWIR spectrum. Recent advances in high energy lasers have renewed the development of laser weapons systems. The ability to measure and assess laser source information is important to both identify a potential threat as well as determine safety and nominal hazard zone (NHZ). Laser detection sensors are required that provide high dynamic range, wide spectral coverage, pulsed and continuous wave detection, and large field of view. OPTRA, Inc. and Tufts have developed a custom ROIC smart pixel imaging sensor architecture and wavelength encoding optics for measurement of source wavelength, pulse length, pulse repetition frequency (PRF), irradiance, and angle of arrival. The smart architecture provides dual linear and logarithmic operating modes to provide 8+ orders of signal dynamic range and nanosecond pulse measurement capability that can be hybridized with the appropriate detector array to provide UV through LWIR laser sensing. Recent advances in sputtering techniques provide the capability for post-processing CMOS dies from the foundry and patterning PbS and PbSe photoconductors directly on the chip to create a single monolithic sensor array architecture for measuring sources operating from 0.26 - 5.0 microns, 1 mW/cm2 - 2 kW/cm2.

Surface calculations with asymptotically long-ranged potentials in the full-potential linearized augmented plane-wave method

NASA Astrophysics Data System (ADS)

Ye, Lin-Hui

2015-09-01

Although the supercell method has been widely used for surface calculations, it only works well with short-ranged potentials, but meets difficulty when the potential decays very slowly into the vacuum. Unfortunately, the exact exchange-correlation potential of the density functional theory is asymptotically long ranged, and therefore is not easily handled by use of supercells. This paper illustrates that the authentic slab geometry, another technique for surface calculations, is not affected by this issue: It works equally well with both short- and long-ranged potentials, with the computational cost and the convergence speed being essentially the same. Using the asymptotically long-ranged Becke-Roussel'89 exchange potential as an example, we have calculated six surfaces of various types. We found that accurate potential values can be obtained even in extremely low density regions of more than 100 Å away from the surface. This high performance allows us to explore the asymptotic region, and prove with clean numerical evidence that the Becke-Roussel'89 potential satisfies the correct asymptotic behavior for slab surfaces, as it does for finite systems. Our finding further implies that the Slater component of the exact exchange optimized effective potential is responsible for the asymptotic behavior, not only for jellium slabs, but for slabs of any type. The Becke-Roussel'89 potential may therefore be used to build asymptotically correct model exchange potentials applicable to both finite systems and slab surfaces.

Use of Nitrogen-15 Isotope Method in Soils and Ground Water to Determine Potential Nitrogen Sources Affecting a Municipal Water Supply in Kansas, USA

NASA Astrophysics Data System (ADS)

Townsend, M. A.; Macko, S. A.

2004-12-01

Nitrate-N concentrations have increased to greater than 10 mg/L in a municipal water supply in western Kansas from 1995 to 2002. A study was done by the Kansas Geological Survey using the nitrogen-15 natural abundance isotope method to determine potential sources for the increasing nitrate concentrations. Preliminary results of the isotope analyses on water samples suggest that animal waste and/or denitrification enrichment has affected the water supply. Soil samples from areas near the wells that were not treated with manure show a general increase of nitrogen-15 signature (+9 to +15 \\permil) to a depth of 5 m. Soils are silt loams with measurable carbonate (0.8 to 2 % by weight) in the profile, which may permit volatilization enrichment to occur in the soil profile. Wells in the area range from 11 to 20 m in alluvial deposits with depth to water at approximately 9 m). Nitrate-N values range from 8 to 26 mg/L. Nitrogen-15 values range from (+17 to +28 \\permil) with no obvious source of animal waste near the well sites. There are potential nearby long-term sources of animal waste - an abandoned sewage treatment plant and an agricultural testing farm. One well has a reducing chemistry with a nitrate value of 0.9 mg/L and a nitrogen-15 value of +17 \\permil suggesting that alluvial sediment variation also has an impact on the water quality in the study area. The other wells show values of nitrate and nitrogen-15 that are much greater than the associated soils. The use of nitrogen-15 alone permited limited evaluation of sources of nitrate to ground water particularly in areas with carbonate in the soils. Use of oxygen-18 on nitrate will permit the delineation of the processes affecting the nitrogen in the soil profile and determination of the probable sources and the processes that have affected the nitrogen in the ground water. Final results of the nitrogen-15 and oxygen-18 analyses will be presented.

Rafting rocks reveal marine biological dispersal: A case study using clasts from beach-cast macroalgal holdfasts

NASA Astrophysics Data System (ADS)

Garden, Christopher J.; Craw, Dave; Waters, Jonathan M.; Smith, Abigail

2011-12-01

Tracking and quantifying biological dispersal presents a major challenge in marine systems. Most existing methods for measuring dispersal are limited by poor resolution and/or high cost. Here we use geological data to quantify the frequency of long-distance dispersal in detached bull-kelp (Phaeophyceae: Durvillaea) in southern New Zealand. Geological resolution in this region is enhanced by the presence of a number of distinct and readily-identifiable geological terranes. We sampled 13,815 beach-cast bull-kelp plants across 130 km of coastline. Rocks were found attached to 2639 of the rafted plants, and were assigned to specific geological terranes (source regions) to quantify dispersal frequencies and distances. Although the majority of kelp-associated rock specimens were found to be locally-derived, a substantial number (4%) showed clear geological evidence of long-distance dispersal, several having travelled over 200 km from their original source regions. The proportion of local versus foreign clasts varied considerably between regions. While short-range dispersal clearly predominates, long-distance travel of detached bull-kelp plants is shown to be a common and ongoing process that has potential to connect isolated coastal populations. Geological analyses represent a cost-effective and powerful method for assigning large numbers of drifted macroalgae to their original source regions.

Commercial objectives, technology transfer, and systems analysis for fusion power development

NASA Astrophysics Data System (ADS)

Dean, Stephen O.

1988-03-01

Fusion is an essentially inexhaustible source of energy that has the potential for economically attractive commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion-energy development program is the generation of centralstation electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high-energy neutrons suggests potentially unique applications. These include breeding of fissile fuels, production of hydrogen and other chemical products, transmutation or “burning” of various nuclear or chemical wastes, radiation processing of materials, production of radioisotopes, food preservation, medical diagnosis and medical treatment, and space power and space propulsion. In addition, fusion R&D will lead to new products and new markets. Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other hand, are the two primary criteria for setting long-range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R&D program toward practical applications. The transfer of fusion technology and skills from the national laboratories and universities to industry is the key to achieving the long-range objective of commercial fusion applications.

Biogas Potential on Long Island, New York: A Quantification Study

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

Mahajan, D.; Patel, S.; Tonjes, D.

2011-08-25

Biogas is the product of anaerobic digestion of waste, whether occurring spontaneously in landfills or under controlled conditions in digesters. Biogas is viewed as an important energy source in current efforts to reduce the use of fossil fuels and dependency on imported resources. Several studies on the assessment of biogas potential have been made at regional, national, and global scales. However, because it is not economically feasible to transport biogas feedstock over long distances, it is more appropriate to consider local waste sources for their potential to produce biogas. An assessment of the biogas potential on Long Island, based onmore » the review of local landfills, wastewater treatment plants, solid waste generation and management, and agricultural waste, found that 234 x 10{sup 6} m{sup 3} of methane (CH{sub 4}) from biogas might be harvestable, although substantial barriers for complete exploitation exist. This number is equivalent to 2.52 TW-h of electricity, approximately 12% of fossil fuel power generation on Long Island. This work can serve as a template for other areas to rapidly create or approximate biogas potentials, especially for suburban U.S. locations that are not usually thought of as sources of renewable energy.« less

Source apportionment of population representative samples of PM(2.5) in three European cities using structural equation modelling.

PubMed

Ilacqua, Vito; Hänninen, Otto; Saarela, Kristina; Katsouyanni, Klea; Künzli, Nino; Jantunen, Matti

2007-10-01

Apportionment of urban particulate matter (PM) to sources is central for air quality management and efficient reduction of the substantial public health risks associated with fine particles (PM(2.5)). Traffic is an important source combustion particles, but also a significant source of resuspended particles that chemically resemble Earth's crust and that are not affected by development of cleaner motor technologies. A substantial fraction of urban ambient PM originates from long-range transport outside the immediate urban environment including secondary particles formed from gaseous emissions of mainly sulphur, nitrogen oxides and ammonia. Most source apportionment studies are based on small number of fixed monitoring sites and capture well population exposures to regional and long-range transported particles. However, concentrations from local sources are very unevenly distributed and the results from such studies are therefore poorly representative of the actual exposures. The current study uses PM(2.5) data observed at population based random sampled residential locations in Athens, Basle and Helsinki with 17 elemental constituents, selected VOCs (xylenes, trimethylbenzenes, nonane and benzene) and light absorbance (black smoke). The major sources identified across the three cities included crustal, salt, long-range transported inorganic and traffic sources. Traffic was associated separately with source categories with crustal (especially Athens and Helsinki) and long-range transported chemical composition (all cities). Remarkably high fractions of the variability of elemental (R(2)>0.6 except for Ca in Basle 0.38) and chemical concentrations (R(2)>0.5 except benzene in Basle 0.22 and nonane in Athens 0.39) are explained by the source factors of an SEM model. The RAINS model that is currently used as the main tool in developing European air quality management policies seems to capture the local urban fraction (the city delta term) quite well, but underestimates crustal particle levels in the three cities of the current study. Utilizing structural equation modelling parallel with traditional principal component analysis (PCA) provides an objective method to determine the number of factors to be retained in a model and allows for formal hypotheses testing.

Modified Lippmann--Schwinger equations for two-body scattering theory with long-range interactions

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

Prugovecki, E.; Zorbas, J.

Two kinds of modified Lippmann-Schwinger equations are derived for the case of long-range potentials. The equations of the first kind are homogeneous and are a direct result of the fact that the standard Lippmann-Schwinger equations do not hold when long-range forces are present. The equations of the second kind depend on the existence of an operator Z such that W/sub plus or minus /=s-lim exp(iHt)Z exp-(-iHot). A general recipe for constructing Z is given and ita computation is carried through for the case of asymptotically Coulombic potentials. The resulting equations are used to compare the long-range theory with the theorymore » with a space cutoff (i.e., screened potential) in the limit in which that cutoff is being removed. (auth)« less

Comparison of transport pathways and potential sources of PM10 in two cities around a large Chinese lake using the modified trajectory analysis

NASA Astrophysics Data System (ADS)

Kong, Xiangzhen; He, Wei; Qin, Ning; He, Qishuang; Yang, Bin; Ouyang, Huiling; Wang, Qingmei; Xu, Fuliu

2013-03-01

Trajectory cluster analysis, including the two-stage cluster method based on Euclidean metrics and the one-stage clustering method based on Mahalanobis metrics and self-organizing maps (SOM), was applied and compared to identify the transport pathways of PM10 for the cities of Chaohu and Hefei, both located near Lake Chaohu in China. The two-stage cluster method was modified to further investigate the long trajectories in the second stage in order to eliminate the observed disaggregation among them. Twelve trajectory clusters were identified for both cities. The one-stage clustering method based on Mahalanobis metrics gives the best performance regarding the variances within clusters. The results showed that local PM10 emission was one of the most important sources in both cities and that the local emission in Hefei was higher than in Chaohu. In addition, Chaohu suffered greater effects from the eastern region (Yangtze River Delta, YRD) than Hefei. On the other hand, the long-range transportation from the northwestern pathway had a higher influence on the PM10 level in Hefei. Receptor models, including potential source contribution function (PSCF) and residence time weighted concentrations (RTWC), were utilized to identify the potential source locations of PM10 for both cities. However, the combined PSCF and RTWC results for the two cities provided PM10 source locations that were more consistent with the results of transport pathways and the total anthropogenic PM10 emission inventory. This indicates that the combined method's ability to identify the source regions is superior to that of the individual PSCF or RTWC methods. Henan and Shanxi Provinces and the YRD were important PM10 source regions for the two cities, but the Henan and Shanxi area was more important for Hefei than for Chaohu, while the YRD region was less important. In addition, the PSCF, RTWC and the combined results all had higher correlation coefficients with PM10 emission from traffic than from industry, electricity generation or residential sources, suggesting the relatively higher contribution of traffic emissions to the PM10 pollution in Lake Chaohu.

Impact of Emissions and Long-Range Transport on Multi-Decadal Aerosol Trends: Implications for Air Quality and Climate

NASA Technical Reports Server (NTRS)

Chin, Mian

2012-01-01

We present a global model analysis of the impact of long-range transport and anthropogenic emissions on the aerosol trends in the major pollution regions in the northern hemisphere and in the Arctic in the past three decades. We will use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model to analyze the multi-spatial and temporal scale data, including observations from Terra, Aqua, and CALIPSO satellites and from the long-term surface monitoring stations. We will analyze the source attribution (SA) and source-receptor (SR) relationships in North America, Europe, East Asia, South Asia, and the Arctic at the surface and free troposphere and establish the quantitative linkages between emissions from different source regions. We will discuss the implications for regional air quality and climate change.

Emission Inventory for PFOS in China: Review of Past Methodologies and Suggestions

PubMed Central

Lim, Theodore Chao; Wang, Bin; Huang, Jun; Deng, Shubo; Yu, Gang

2011-01-01

Perfluorooctane sulfonate (PFOS) is a persistent, bioaccumulative, and toxic chemical that has the potential for long-range transport in the environment. Its use in a wide variety of consumer products and industrial processes makes a detailed characterization of its emissions sources very challenging. These varied emissions sources all contribute to PFOS' existence within nearly all environmental media. Currently, China is the only country documented to still be producing PFOS, though there is no China PFOS emission inventory available. This study reviews the inventory methodologies for PFOS in other countries to suggest a China-specific methodology framework for a PFOS emission inventory. The suggested framework combines unknowns for PFOS-containing product penetration into the Chinese market with product lifecycle assumptions, centralizing these diverse sources into municipal sewage treatment plants. Releases from industrial sources can be quantified separately using another set of emission factors. Industrial sources likely to be relevant to the Chinese environment are identified. PMID:22125449

Constructing high-accuracy intermolecular potential energy surface with multi-dimension Morse/Long-Range model

NASA Astrophysics Data System (ADS)

Zhai, Yu; Li, Hui; Le Roy, Robert J.

2018-04-01

Spectroscopically accurate Potential Energy Surfaces (PESs) are fundamental for explaining and making predictions of the infrared and microwave spectra of van der Waals (vdW) complexes, and the model used for the potential energy function is critically important for providing accurate, robust and portable analytical PESs. The Morse/Long-Range (MLR) model has proved to be one of the most general, flexible and accurate one-dimensional (1D) model potentials, as it has physically meaningful parameters, is flexible, smooth and differentiable everywhere, to all orders and extrapolates sensibly at both long and short ranges. The Multi-Dimensional Morse/Long-Range (mdMLR) potential energy model described herein is based on that 1D MLR model, and has proved to be effective and accurate in the potentiology of various types of vdW complexes. In this paper, we review the current status of development of the mdMLR model and its application to vdW complexes. The future of the mdMLR model is also discussed. This review can serve as a tutorial for the construction of an mdMLR PES.

Long-term enrichment of the stable isotopic composition of stream water due to the release of groundwater recharge from extreme precipitation events

NASA Astrophysics Data System (ADS)

Boutt, D. F.

2017-12-01

The isotopic composition of surface and groundwater is impacted by a multitude of hydrologic processes. The long-term response of these systems to hydrologic change is critical for appropriately interpreting isotopic information for streamflow generation, stream-aquifer-coupling, sources of water to wells, and understanding recharge processes. To evaluate the response time of stream-aquifer systems to extreme precipitation events we use a long-term isotope dataset from Western Massachusetts with drainage areas ranging from 0.1 to > 800 km2. The year of 2011 was the wettest calendar year on record and the months of August and September of 2011 were the wettest consecutive two-month period in the 123 year record. Stable isotopic composition of surface waters of catchments ranging from 1 - 1000 km2 show an enrichment due to summertime and Tropical Storm precipitation. Enrichment in potential recharge water is shown to have a significant long-term impact (> 3 hydrologic years) on the isotopic composition of both surface and groundwater. This highlights the importance of groundwater sources of baseflow to streams and the transient storage and release mechanisms of shallow groundwater storage. The length of isotopic recession of stream water are also a strong function of watershed area. It is concluded that the stream water isotopes are consistent with a large pulse of water being stored and released from enriched groundwater emplaced during this period of above-average precipitation. Ultimately the results point to the importance of considering hydrological processes of streamflow generation and their role in hydrologic processes beyond traditional catchment response analysis.

Local contamination, and not feeding preferences, explains elevated PCB concentrations in Labrador ringed seals (Pusa hispida).

PubMed

Brown, Tanya M; Iverson, Sara J; Fisk, Aaron T; Macdonald, Robie W; Helbing, Caren C; Reimer, Ken J

2015-05-15

Polychlorinated biphenyls (PCBs) in high trophic level species typically reflect the contributions of myriad sources, such that source apportionment is rarely possible. The release of PCBs by a military radar station into Saglek Bay, Labrador contaminated the local marine food web. For instance, while heavier (higher chlorinated) PCB profiles in some ringed seals (Pusa hispida) were previously attributed to this local source, differences in feeding preferences among seals could not be ruled out as a contributing factor. Herein, similar fatty acid profiles between those seals with 'local' PCB profiles and those with 'long-range' or background profiles indicate little support for the possibility that differential feeding ecologies underlay the divergent PCB profiles. Ringed seals appeared to feed predominantly on zooplankton (Mysis oculata and Themisto libellula), followed by the dusky snailfish (Liparis gibbus), arctic cod (Boreogadus saida), and shorthorn sculpin (Myoxocephalus scorpius). Principal components analysis (PCA) and PCB homolog profiles illustrated the extent of contamination of the Saglek food web, which had very different (and much heavier) PCB profiles than those food web members contaminated by 'long-range' sources. Locally contaminated prey had PCB levels that were higher (2- to 544-fold) than prey contaminated by 'long-range' sources and exceeded wildlife consumption guidelines for PCBs. The application of multivariate analyses to two distinct datasets, including PCB congeners (n=50) and fatty acids (n=65), afforded the opportunity to clearly distinguish the contribution of locally-released PCBs to a ringed seal food web from those delivered via long-ranged transport. Results from the present study strongly suggest that habitat use rather than differences in prey selection is the primary mechanism explaining the divergent PCB patterns in Labrador ringed seals. Copyright © 2015 Elsevier B.V. All rights reserved.

Noise and degradation of amorphous silicon devices

NASA Astrophysics Data System (ADS)

Bakker, J. P. R.

2003-10-01

Electrical noise measurements are reported on two devices of the disordered semiconductor hydrogenated amorphous silicon (a-Si:H). The material is applied in sandwich structures and in thin-film transistors (TFTs). In a sandwich configuration of an intrinsic layer and two thin doped layers, the observed 1/f resistance noise can be attributed to a distribution of energy levels in the system. Two candidates which eventually could explain the origin of the energy distribution are investigated: generation-recombination noise and long-range potential fluctuations. A simulation program was applied to fit the current-voltage characteristics and resolves the defect density, the energy position and width of the Gaussian distributions of deep defects. Generation-recombination (g-r) is calculated for a one-dimensional semiconductor device with traps, taking the transport of local fluctuations into account. Although the times characterizing capture and emission for deep defects are in the right (ms) range, the calculated noise intensity is five to six orders of magnitude below the measured noise level. Another noise source must cause the 1/f noise in a-Si:H. The alternative is provided by the theory of long-range potential fluctuations. The timescale of the fluctuations is again the capture or emission time for deep defects. When an electron is emitted or captured, the charge state of a deep defect fluctuates. As a result, the potential around that defect will fluctuate, being screened by the surrounding defects. Free electrons will instantaneously adjust to the local potential. The adjustment causes a resistance fluctuation, which is measured as a voltage fluctuation in presence of a constant current. The theory predicts the noise intensity accurately, without any adjustable parameters. Unlike the intensity, the spectral shape is fitted by adjustment of two parameters of the potential landscape. The complete temperature dependence of the noise spectra is consistently described by a Gaussian distribution of potential barriers, located 0.27 eV above the conduction band edge, with a halfwidth of 0.09 eV. A large number of experiments is explained by the theory of long-range potential fluctuations: the thickness dependence, the absence of an isotope effect and the analogous results for oppositely doped devices. From these experiments, it is concluded that a universal potential landscape exists in undoped a-Si:H. Further, the relation between degradation upon prolonged light-soaking and noise is studied. After degradation, the curvature of noise spectra is unaffected, while the intensity increases slightly. These observations are consistent with the theoretical predictions using the observed increase of the defect density. It seems that the potential landscape does not change significantly upon degradation. Noise measurements in the sub-threshold regime of a-Si:H TFTs turn out to yield diffusion noise. Diffusion of electrons through the one-dimensional channel is identified as the source of the noise. The drift mobility extracted from the combined noise and conduction data is below the value that characterizes the on-state. The number of free electrons as determined from combined noise and conduction measurements are in quantitative agreement with an alternative determination from conduction measurements only.

Determining the contribution of long-range transport, regional and local source areas, to PM10 mass loading in Hessen, Germany using a novel multi-receptor based statistical approach

NASA Astrophysics Data System (ADS)

Garg, Saryu; Sinha, Baerbel

2017-10-01

This study uses two newly developed statistical source apportionment models, MuSAM and MuReSAM, to perform quantitative statistical source apportionment of PM10 at multiple receptor sites in South Hessen. MuSAM uses multi-site back trajectory data to quantify the contribution of long-range transport, while MuReSAM uses wind speed and direction as proxy for regional transport and quantifies the contribution of regional source areas. On average, between 7.8 and 9.1 μg/m3 of PM10 (∼50%) at receptor sites in South Hessen is contributed by long-range transport. The dominant source regions are Eastern, South Eastern, and Southern Europe. 32% of the PM10 at receptor sites in South Hessen is contributed by regional source areas (2.8-9.41 μg/m3). This fraction varies from <20% at remote sites to >40% for urban stations. Sources located within a 2 km radius around the receptor site are responsible for 7%-20% of the total PM10 mass (0.7-4.4 μg/m3). The perturbation study of the traffic flow due to the closing and reopening of the Schiersteiner Brücke revealed that the contribution of the bridge to PM10 mass loadings at two nearby receptor sites increased by approximately 120% after it reopened and became a bottleneck, although in absolute terms, the increase is small.

Optimisation of a propagation-based x-ray phase-contrast micro-CT system

NASA Astrophysics Data System (ADS)

Nesterets, Yakov I.; Gureyev, Timur E.; Dimmock, Matthew R.

2018-03-01

Micro-CT scanners find applications in many areas ranging from biomedical research to material sciences. In order to provide spatial resolution on a micron scale, these scanners are usually equipped with micro-focus, low-power x-ray sources and hence require long scanning times to produce high resolution 3D images of the object with acceptable contrast-to-noise. Propagation-based phase-contrast tomography (PB-PCT) has the potential to significantly improve the contrast-to-noise ratio (CNR) or, alternatively, reduce the image acquisition time while preserving the CNR and the spatial resolution. We propose a general approach for the optimisation of the PB-PCT imaging system. When applied to an imaging system with fixed parameters of the source and detector this approach requires optimisation of only two independent geometrical parameters of the imaging system, i.e. the source-to-object distance R 1 and geometrical magnification M, in order to produce the best spatial resolution and CNR. If, in addition to R 1 and M, the system parameter space also includes the source size and the anode potential this approach allows one to find a unique configuration of the imaging system that produces the required spatial resolution and the best CNR.

Long-Range Planning--Finances. Higher Education.

ERIC Educational Resources Information Center

Ward, Robert C.

This paper presents views on long-range financial planning for public and private higher education. Emphasis is placed on a mix of revenue sources for future support and on key budgetary considerations such as faculty and non-academic wages, the rising cost of graduate education, and the community and junior college movement. A triple crisis is…

Source analysis of short and long latency vestibular-evoked potentials (VsEPs) produced by left vs. right ear air-conducted 500 Hz tone pips.

PubMed

Todd, N P M; Paillard, A C; Kluk, K; Whittle, E; Colebatch, J G

2014-06-01

Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulation and by conducting a source analysis of the resulting evoked potentials of short and long latency. Ten healthy, right-handed subjects were recruited and evoked potentials were recorded to both left- and right-ear sound stimulation, above and below vestibular threshold. Below VEMP threshold, typical AEPs were recorded, consisting of mid-latency (MLR) waves Na and Pa followed by long latency AEPs (LAEPs) N1 and P2. In the supra-threshold condition, the expected changes in morphology were observed, consisting of: (1) short-latency vestibular evoked potentials (VsEPs) which have no auditory correlate, i.e. the ocular VEMP (OVEMP) and inion response related potentials; (2) a later deflection, labelled N42/P52, followed by the LAEPs N1 and P2. Statistical analysis of the vestibular dependent responses indicated a contralateral effect for inion related short-latency responses and a left-ear/right-hemisphere advantage for the long-latency responses. Source analysis indicated that the short-latency effects may be mediated by a contralateral projection to left cerebellum, while the long-latency effects were mediated by a contralateral projection to right cingulate cortex. In addition we found evidence of a possible vestibular contribution to the auditory T-complex in radial temporal lobe sources. These last results raise the possibility that acoustic activation of the otolith organs could potentially contribute to auditory processing. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Encountering bird alarms in full-stare IRSTs

NASA Astrophysics Data System (ADS)

de Jong, Arie N.; Winkel, Hans; Kemp, Rob A. W.

2000-12-01

Birds are a potential source of frequent false alarms in Infrared Search and Track (IRST) systems. One reason is that the signals, generated by birds at short ranges (1-2 km) in IR sensors may be of the same magnitude as the signals generated by real targets (missiles) at long ranges (10-20 km). Another reason is that new generations of IRSTs have more sensitivity which brings more birds within the detection range. Furthermore military operations tend to be held more and more in coastal zones, where the frequency of occurrence of birds is greater than in the open ocean. Finally, the variety in type of birds and their flight characteristics and signature is larger. In the paper attention is spent on the IR signatures of birds in various backgrounds, including rapid variations in signature due to wing motions. Basically, these fluctuations and the flight pattern of a bird provide opportunities to encounter bird alarms in next generation IRSTs, using multiple Focal Plan Array cameras with high frame rates. One has to take into account in this process the difference between signal variations due to wing motions and scintillation for long range targets above the horizon.

Patterns formation in ferrofluids and solid dissolutions using stochastic models with dissipative dynamics

NASA Astrophysics Data System (ADS)

Morales, Marco A.; Fernández-Cervantes, Irving; Agustín-Serrano, Ricardo; Anzo, Andrés; Sampedro, Mercedes P.

2016-08-01

A functional with interactions short-range and long-range low coarse-grained approximation is proposed. This functional satisfies models with dissipative dynamics A, B and the stochastic Swift-Hohenberg equation. Furthermore, terms associated with multiplicative noise source are added in these models. These models are solved numerically using the method known as fast Fourier transform. Results of the spatio-temporal dynamic show similarity with respect to patterns behaviour in ferrofluids phases subject to external fields (magnetic, electric and temperature), as well as with the nucleation and growth phenomena present in some solid dissolutions. As a result of the multiplicative noise effect over the dynamic, some microstructures formed by changing solid phase and composed by binary alloys of Pb-Sn, Fe-C and Cu-Ni, as well as a NiAl-Cr(Mo) eutectic composite material. The model A for active-particles with a non-potential term in form of quadratic gradient explain the formation of nanostructured particles of silver phosphate. With these models is shown that the underlying mechanisms in the patterns formation in all these systems depends of: (a) dissipative dynamics; (b) the short-range and long-range interactions and (c) the appropiate combination of quadratic and multiplicative noise terms.

Formula for the Transition Probability Induced by Long-range Potential Terms Varying as R-8 and R-10 for Atom-dimer Collisions

NASA Astrophysics Data System (ADS)

Matthews, N. F.; Robson, D.; Grant, M. A.

1990-12-01

An explicit formula is derived for the transition probability between two different states of the atom-dimer collisional system governed by second-order long-range interaction potential terms varying as R-8 and R-10.

Characteristics of total gaseous mercury (TGM) concentrations in an industrial complex in South Korea: impacts from local sources

NASA Astrophysics Data System (ADS)

Seo, Yong-Seok; Jeong, Seung-Pyo; Holsen, Thomas M.; Han, Young-Ji; Choi, Eunhwa; Park, Eun Ha; Kim, Tae Young; Eum, Hee-Sang; Park, Dae Gun; Kim, Eunhye; Kim, Soontae; Kim, Jeong-Hun; Choi, Jaewon; Yi, Seung-Muk

2016-08-01

Total gaseous mercury (TGM) concentrations were measured every 5 min in Pohang, Gyeongsangbuk-do, Korea, during summer (17-23 August 2012), fall (9-17 October 2012), winter (22-29 January 2013), and spring (26 March-3 April 2013) to (1) characterize the hourly and seasonal variations of atmospheric TGM concentrations; (2) identify the relationships between TGM and co-pollutants; and (3) identify likely source directions and locations of TGM using the conditional probability function (CPF), conditional bivariate probability function (CBPF) and total potential source contribution function (TPSCF). The TGM concentration was statistically significantly highest in fall (6.7 ± 6.4 ng m-3), followed by spring (4.8 ± 4.0 ng m-3), winter (4.5 ± 3.2 ng m-3) and summer (3.8 ± 3.9 ng m-3). There was a weak but statistically significant negative correlation between the TGM concentration and ambient air temperature (r = -0.08, p<0.05). Although the daytime temperature (14.7 ± 10.0 °C) was statistically significantly higher than that in the nighttime (13.0 ± 9.8 °C) (p<0.05), the daytime TGM concentration (5.3 ± 4.7 ng m-3) was statistically significantly higher than that in the nighttime (4.7 ± 4.7 ng m-3) (p<0.01), possibly due to local emissions related to industrial activities and activation of local surface emission sources. The observed ΔTGM / ΔCO was significantly lower than that of Asian long-range transport, but similar to that of local sources in Korea and in US industrial events, suggesting that local sources are more important than those of long-range transport. CPF, CBPF and TPSCF indicated that the main sources of TGM were iron and manufacturing facilities, the hazardous waste incinerators and the coastal areas.

Can fungi compete with marine sources for chitosan production?

PubMed

Ghormade, V; Pathan, E K; Deshpande, M V

2017-11-01

Chitosan, a β-1,4-linked glucosamine polymer is formed by deacetylation of chitin. It has a wide range of applications from agriculture to human health care products. Chitosan is commercially produced from shellfish, shrimp waste, crab and lobster processing using strong alkalis at high temperatures for long time periods. The production of chitin and chitosan from fungal sources has gained increased attention in recent years due to potential advantages in terms of homogenous polymer length, high degree of deacetylation and solubility over the current marine source. Zygomycetous fungi such as Absidia coerulea, Benjaminiella poitrasii, Cunninghamella elegans, Gongrenella butleri, Mucor rouxii, Mucor racemosus and Rhizopus oryzae have been studied extensively. Isolation of chitosan are reported from few edible basidiomycetous fungi like Agaricus bisporus, Lentinula edodes and Pleurotus sajor-caju. Other organisms from mycotech industries explored for chitosan production are Aspergillus niger, Penicillium chrysogenum, Saccharomyces cerevisiae and other wine yeasts. Number of aspects such as value addition to the existing applications of fungi, utilization of waste from agriculture sector, and issues and challenges for the production of fungal chitosan to compete with existing sources, metabolic engineering and novel applications have been discussed to adjudge the potential of fungal sources for commercial chitosan production. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization technique for long optical fiber cavities based on beating spectrum of multi-longitudinal mode fiber laser and beating spectrum in the RF domain

NASA Astrophysics Data System (ADS)

Adib, George A.; Sabry, Yasser M.; Khalil, Diaa

2016-03-01

The characterization of long fiber cavities is essential for many systems to predict the system practical performance. The conventional techniques for optical cavity characterization are not suitable for long fiber cavities due to the cavities' small free spectral ranges and due to the length variations caused by the environmental effects. In this work, we present a novel technique to characterize long fiber cavities using multi-longitudinal mode fiber laser source and RF spectrum analyzer. The fiber laser source is formed in a ring configuration, where the fiber laser cavity length is chosen to be 15 km to ensure that the free spectral range is much smaller than the free spectral range of the characterized passive fiber cavities. The method has been applied experimentally to characterize ring cavities with lengths of 6.2 m and 2.4 km. The results are compared to theoretical predictions with very good agreement.

Underestimated risks of recurrent long-range ash dispersal from northern Pacific Arc volcanoes

PubMed Central

Bourne, A. J.; Abbott, P. M.; Albert, P. G.; Cook, E.; Pearce, N. J. G.; Ponomareva, V.; Svensson, A.; Davies, S. M.

2016-01-01

Widespread ash dispersal poses a significant natural hazard to society, particularly in relation to disruption to aviation. Assessing the extent of the threat of far-travelled ash clouds on flight paths is substantially hindered by an incomplete volcanic history and an underestimation of the potential reach of distant eruptive centres. The risk of extensive ash clouds to aviation is thus poorly quantified. New evidence is presented of explosive Late Pleistocene eruptions in the Pacific Arc, currently undocumented in the proximal geological record, which dispersed ash up to 8000 km from source. Twelve microscopic ash deposits or cryptotephra, invisible to the naked eye, discovered within Greenland ice-cores, and ranging in age between 11.1 and 83.7 ka b2k, are compositionally matched to northern Pacific Arc sources including Japan, Kamchatka, Cascades and Alaska. Only two cryptotephra deposits are correlated to known high-magnitude eruptions (Towada-H, Japan, ca 15 ka BP and Mount St Helens Set M, ca 28 ka BP). For the remaining 10 deposits, there is no evidence of age- and compositionally-equivalent eruptive events in regional volcanic stratigraphies. This highlights the inherent problem of under-reporting eruptions and the dangers of underestimating the long-term risk of widespread ash dispersal for trans-Pacific and trans-Atlantic flight routes. PMID:27445233

Underestimated risks of recurrent long-range ash dispersal from northern Pacific Arc volcanoes.

PubMed

Bourne, A J; Abbott, P M; Albert, P G; Cook, E; Pearce, N J G; Ponomareva, V; Svensson, A; Davies, S M

2016-07-21

Widespread ash dispersal poses a significant natural hazard to society, particularly in relation to disruption to aviation. Assessing the extent of the threat of far-travelled ash clouds on flight paths is substantially hindered by an incomplete volcanic history and an underestimation of the potential reach of distant eruptive centres. The risk of extensive ash clouds to aviation is thus poorly quantified. New evidence is presented of explosive Late Pleistocene eruptions in the Pacific Arc, currently undocumented in the proximal geological record, which dispersed ash up to 8000 km from source. Twelve microscopic ash deposits or cryptotephra, invisible to the naked eye, discovered within Greenland ice-cores, and ranging in age between 11.1 and 83.7 ka b2k, are compositionally matched to northern Pacific Arc sources including Japan, Kamchatka, Cascades and Alaska. Only two cryptotephra deposits are correlated to known high-magnitude eruptions (Towada-H, Japan, ca 15 ka BP and Mount St Helens Set M, ca 28 ka BP). For the remaining 10 deposits, there is no evidence of age- and compositionally-equivalent eruptive events in regional volcanic stratigraphies. This highlights the inherent problem of under-reporting eruptions and the dangers of underestimating the long-term risk of widespread ash dispersal for trans-Pacific and trans-Atlantic flight routes.

Transport of pollutants considered from the point of view of a short and medium range-material balance

Treesearch

Michel Benaire

1976-01-01

Episodical long-range transport is the quasi-instantaneous peak event. It does not express the total dosage of pollutant carried over from the source area to some distant place. The purpose of the present paper is to obtain an average material balance of a pollutant leaving a given area. Available information from the OECD "Long Range Transport of Air Pollutants...

Configuration of electro-optic fire source detection system

NASA Astrophysics Data System (ADS)

Fabian, Ram Z.; Steiner, Zeev; Hofman, Nir

2007-04-01

The recent fighting activities in various parts of the world have highlighted the need for accurate fire source detection on one hand and fast "sensor to shooter cycle" capabilities on the other. Both needs can be met by the SPOTLITE system which dramatically enhances the capability to rapidly engage hostile fire source with a minimum of casualties to friendly force and to innocent bystanders. Modular system design enable to meet each customer specific requirements and enable excellent future growth and upgrade potential. The design and built of a fire source detection system is governed by sets of requirements issued by the operators. This can be translated into the following design criteria: I) Long range, fast and accurate fire source detection capability. II) Different threat detection and classification capability. III) Threat investigation capability. IV) Fire source data distribution capability (Location, direction, video image, voice). V) Men portability. ) In order to meet these design criteria, an optimized concept was presented and exercised for the SPOTLITE system. Three major modular components were defined: I) Electro Optical Unit -Including FLIR camera, CCD camera, Laser Range Finder and Marker II) Electronic Unit -including system computer and electronic. III) Controller Station Unit - Including the HMI of the system. This article discusses the system's components definition and optimization processes, and also show how SPOTLITE designers successfully managed to introduce excellent solutions for other system parameters.

Steady state deformation of the Coso Range, east central California, inferred from satellite radar interferometry

USGS Publications Warehouse

Wicks, C.W.; Thatcher, W.; Monastero, F.C.; Hasting, M.A.

2001-01-01

Observations of deformation from 1992 to 1997 in the southern Coso Range using satellite radar interferometry show deformation rates of up to 35 mm yr-1 in an area ???10 km by 15 km. The deformation is most likely the result of subsidence in an area around the Coso geothermal field. The deformation signal has a short-wavelength component, related to production in the field, and a long-wavelength component, deforming at a constant rate, that may represent a source of deformation deeper than the geothermal reservoir. We have modeled the long-wavelength component of deformation and inferred a deformation source at ???4 km depth. The source depth is near the brittle-ductile transition depth (inferred from seismicity) and ???1.5 km above the top of the rhyolite magma body that was a source for the most recent volcanic eruption in the Coso volcanic field [Manley and Bacon, 2000]. From this evidence and results of other studies in the Coso Range, we interpret the source to be a leaking deep reservoir of magmatic fluids derived from a crystallizing rhyolite magma body.

Campaign datasets for ARM Cloud Aerosol Precipitation Experiment (ACAPEX)

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

Leung, L. Ruby; Mei, Fan; Comstock, Jennifer

This campaign consisted of the deployment of the DOE ARM Mobile Facility 2 (AMF2) and the ARM Aerial Facility (AAF) G-1 in a field campaign called ARM Cloud Aerosol Precipitation Experiment (ACAPEX), which took place in conjunction with CalWater 2- a NOAA field campaign. The joint CalWater 2/ACAPEX field campaign aimed to improve understanding and modeling of large-scale dynamics and cloud and precipitation processes associated with ARs and aerosol-cloud interactions that influence precipitation variability and extremes in the western U.S. The observational strategy consisted of the use of land and offshore assets to monitor: 1. the evolution and structure ofmore » ARs from near their regions of development 2. the long-range transport of aerosols in the eastern North Pacific and potential interactions with ARs 3. how aerosols from long-range transport and local sources influence cloud and precipitation in the U.S. West Coast where ARs make landfall and post-frontal clouds are frequent.« less

Local thermodynamics and the generalized Gibbs-Duhem equation in systems with long-range interactions.

PubMed

Latella, Ivan; Pérez-Madrid, Agustín

2013-10-01

The local thermodynamics of a system with long-range interactions in d dimensions is studied using the mean-field approximation. Long-range interactions are introduced through pair interaction potentials that decay as a power law in the interparticle distance. We compute the local entropy, Helmholtz free energy, and grand potential per particle in the microcanonical, canonical, and grand canonical ensembles, respectively. From the local entropy per particle we obtain the local equation of state of the system by using the condition of local thermodynamic equilibrium. This local equation of state has the form of the ideal gas equation of state, but with the density depending on the potential characterizing long-range interactions. By volume integration of the relation between the different thermodynamic potentials at the local level, we find the corresponding equation satisfied by the potentials at the global level. It is shown that the potential energy enters as a thermodynamic variable that modifies the global thermodynamic potentials. As a result, we find a generalized Gibbs-Duhem equation that relates the potential energy to the temperature, pressure, and chemical potential. For the marginal case where the power of the decaying interaction potential is equal to the dimension of the space, the usual Gibbs-Duhem equation is recovered. As examples of the application of this equation, we consider spatially uniform interaction potentials and the self-gravitating gas. We also point out a close relationship with the thermodynamics of small systems.

The acoustic field of a point source in a uniform boundary layer over an impedance plane

NASA Technical Reports Server (NTRS)

Zorumski, W. E.; Willshire, W. L., Jr.

1986-01-01

The acoustic field of a point source in a boundary layer above an impedance plane is investigated anatytically using Obukhov quasi-potential functions, extending the normal-mode theory of Chunchuzov (1984) to account for the effects of finite ground-plane impedance and source height. The solution is found to be asymptotic to the surface-wave term studies by Wenzel (1974) in the limit of vanishing wind speed, suggesting that normal-mode theory can be used to model the effects of an atmospheric boundary layer on infrasonic sound radiation. Model predictions are derived for noise-generation data obtained by Willshire (1985) at the Medicine Bow wind-turbine facility. Long-range downwind propagation is found to behave as a cylindrical wave, with attention proportional to the wind speed, the boundary-layer displacement thickness, the real part of the ground admittance, and the square of the frequency.

Contents and compositions of policosanols in green tea (Camellia sinensis) leaves.

PubMed

Choi, Sol Ji; Park, Su Yeon; Park, Ji Su; Park, Sang-Kyu; Jung, Mun Yhung

2016-08-01

Policosanol (PC) is a mixture of health promoting bioactive long-chain aliphatic alcohols. Here, we report that green tea (Camellia sinensis) leaves are the exceptionally rich plant-sources of PC. Young and tender leaves and old and turf leaves of C. sinensis were hand-picked in spring and autumn. The total contents of PC in the leaves were in the range of 726.2-1363.6mg/kg as determined by a GC-MS/MS. The compositions of PC in the leaves were different with harvest season and types. The total contents of PC in commercial green tea leaves were found to be in the range of 856.7-1435.1mg/kg. Interestingly, the infused green tea leaves contained the higher PC than the non-infused green tea product, reaching to 1629.4mg/kg. This represents the first report on the contents and compositions of PC in green tea leaves, showing unambiguous evidence of their potential as rich sources of PC. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tracing the origin of pollution in French Alpine snow and aerosols using lead isotopic ratios.

PubMed

Veysseyre, A M; Bollhöfer, A F; Rosman, K J; Ferrari, C P; Boutron, C F

2001-11-15

Fresh snow samples collected at 15 remote locations and aerosols collected at one location in the French Alps between November 1998 and April 1999 have been analyzed for Pb concentration and isotopic composition by thermal ionization mass spectrometry. The snow samples contained 19-1300 pg/g of Pb with isotopic ratios 206Pb/207Pb (208Pb/207Pb) of 1.1279-1.1607 (2.3983-2.4302). Airborne Pb concentrations at one sampling site ranged from 0.42 to 6.0 ng/m3 with isotopic ratios of 1.1321-1.1427 (2.4029-2.4160). Air mass trajectory analysis combined with isotopic compositions of potential source regions did not show discernible evidence of the long-range atmospheric transport of pollutants. Isotopic ratios in the Alpine snow samples and thus the free troposphere were generally higher than airborne Pb isotopic ratios in urban France, which coupled with the relatively high Pb concentrations suggested a regional anthropogenic Pb source, probably Italy but possibly Eastern Europe.

On the use of big-bang method to generate low-energy structures of atomic clusters modeled with pair potentials of different ranges.

PubMed

Marques, J M C; Pais, A A C C; Abreu, P E

2012-02-05

The efficiency of the so-called big-bang method for the optimization of atomic clusters is analysed in detail for Morse pair potentials with different ranges; here, we have used Morse potentials with four different ranges, from long- ρ = 3) to short-ranged ρ = 14) interactions. Specifically, we study the efficacy of the method in discovering low-energy structures, including the putative global minimum, as a function of the potential range and the cluster size. A new global minimum structure for long-ranged ρ = 3) Morse potential at the cluster size of n= 240 is reported. The present results are useful to assess the maximum cluster size for each type of interaction where the global minimum can be discovered with a limited number of big-bang trials. Copyright © 2011 Wiley Periodicals, Inc.

High-harmonic generation in amorphous solids

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

You, Yong Sing; Yin, Yanchun; Wu, Yi

High-harmonic generation in isolated atoms and molecules has been widely utilized in extreme ultraviolet photonics and attosecond pulse metrology. Recently, high-harmonic generation has been observed in solids, which could lead to important applications such as all-optical methods to image valance charge density and reconstruct electronic band structures, as well as compact extreme ultraviolet light sources. So far these studies are confined to crystalline solids; therefore, decoupling the respective roles of long-range periodicity and high density has been challenging. Here we report the observation of high-harmonic generation from amorphous fused silica. We also decouple the role of long-range periodicity by comparingmore » harmonics generated from fused silica and crystalline quartz, which contain the same atomic constituents but differ in long-range periodicity. These results advance current understanding of the strong-field processes leading to high-harmonic generation in solids with implications for the development of robust and compact extreme ultraviolet light sources.« less

High-harmonic generation in amorphous solids

DOE PAGES

You, Yong Sing; Yin, Yanchun; Wu, Yi; ...

2017-09-28

High-harmonic generation in isolated atoms and molecules has been widely utilized in extreme ultraviolet photonics and attosecond pulse metrology. Recently, high-harmonic generation has been observed in solids, which could lead to important applications such as all-optical methods to image valance charge density and reconstruct electronic band structures, as well as compact extreme ultraviolet light sources. So far these studies are confined to crystalline solids; therefore, decoupling the respective roles of long-range periodicity and high density has been challenging. Here we report the observation of high-harmonic generation from amorphous fused silica. We also decouple the role of long-range periodicity by comparingmore » harmonics generated from fused silica and crystalline quartz, which contain the same atomic constituents but differ in long-range periodicity. These results advance current understanding of the strong-field processes leading to high-harmonic generation in solids with implications for the development of robust and compact extreme ultraviolet light sources.« less

Transport of Aerosols: Regional and Global Implications for Climate, Weather, and Air Quality

NASA Technical Reports Server (NTRS)

Chin, Mian; Diehl, Thomas; Yu, Hongbin; Bian, Huisheng; Remer, Lorraine; Kahn, Ralph

2008-01-01

Long-range transport of atmospheric aerosols can have a significant impact on global climate, regional weather, and local air quality. In this study, we use a global model GOCART together with satellite data and ground-based measurements to assess the emission and transport of pollution, dust, biomass burning, and volcanic aerosols and their implications. In particular, we will show the impact of emissions and long-range transport of aerosols from major pollution and dust source regions to (1) the surface air quality, (2) the atmospheric heating rates, and (3) surface radiation change near the source and downwind regions.

Asymmetric multiscale multifractal analysis of wind speed signals

NASA Astrophysics Data System (ADS)

Zhang, Xiaonei; Zeng, Ming; Meng, Qinghao

We develop a new method called asymmetric multiscale multifractal analysis (A-MMA) to explore the multifractality and asymmetric autocorrelations of the signals with a variable scale range. Three numerical experiments are provided to demonstrate the effectiveness of our approach. Then, the proposed method is applied to investigate multifractality and asymmetric autocorrelations of difference sequences between wind speed fluctuations with uptrends or downtrends. The results show that these sequences appear to be far more complex and contain abundant fractal dynamics information. Through analyzing the Hurst surfaces of nine difference sequences, we found that all series exhibit multifractal properties and multiscale structures. Meanwhile, the asymmetric autocorrelations are observed in all variable scale ranges and the asymmetry results are of good consistency within a certain spatial range. The sources of multifractality and asymmetry in nine difference series are further discussed using the corresponding shuffled series and surrogate series. We conclude that the multifractality of these series is due to both long-range autocorrelation and broad probability density function, but the major source of multifractality is long-range autocorrelation, and the source of asymmetry is affected by the spatial distance.

Potential for long-term transfer of dissolved organic carbon from riparian zones to streams in boreal catchments.

PubMed

Ledesma, José L J; Grabs, Thomas; Bishop, Kevin H; Schiff, Sherry L; Köhler, Stephan J

2015-08-01

Boreal regions store most of the global terrestrial carbon, which can be transferred as dissolved organic carbon (DOC) to inland waters with implications for both aquatic ecology and carbon budgets. Headwater riparian zones (RZ) are important sources of DOC, and often just a narrow 'dominant source layer' (DSL) within the riparian profile is responsible for most of the DOC export. Two important questions arise: how long boreal RZ could sustain lateral DOC fluxes as the sole source of exported carbon and how its hydromorphological variability influences this role. We estimate theoretical turnover times by comparing carbon pools and lateral exports in the DSL of 13 riparian profiles distributed over a 69 km(2) catchment in northern Sweden. The thickness of the DSL was 36 ± 18 (average ± SD) cm. Thus, only about one-third of the 1-m-deep riparian profile contributed 90% of the lateral DOC flux. The 13 RZ exported 8.7 ± 6.5 g C m(-2) year(-1) , covering the whole range of boreal stream DOC exports. The variation could be explained by local hydromorphological characteristics including RZ width (R(2) = 0.90). The estimated theoretical turnover times were hundreds to a few thousands of years, that is there is a potential long-lasting supply of DOC. Estimates of net ecosystem production in the RZ suggest that lateral fluxes, including both organic and inorganic C, could be maintained without drawing down the riparian pools. This was supported by measurements of stream DO(14) C that indicated modern carbon as the predominant fraction exported, including streams disturbed by ditching. The transfer of DOC into boreal inland waters from new and old carbon sources has a major influence on surface water quality and global carbon balances. This study highlights the importance of local variations in RZ hydromorphology and DSL extent for future DOC fluxes under a changing climate. © 2015 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Combining measurements and modelling to quantify the contribution of atmospheric fallout, local industry and road traffic to PAH stocks in contrasting catchments.

PubMed

Gateuille, David; Evrard, Olivier; Lefevre, Irène; Moreau-Guigon, Elodie; Alliot, Fabrice; Chevreuil, Marc; Mouchel, Jean-Marie

2014-06-01

Various sources supply PAHs that accumulate in soils. The methodology we developed provided an evaluation of the contribution of local sources (road traffic, local industries) versus remote sources (long range atmospheric transport, fallout and gaseous exchanges) to PAH stocks in two contrasting subcatchments (46-614 km²) of the Seine River basin (France). Soil samples (n = 336) were analysed to investigate the spatial pattern of soil contamination across the catchments and an original combination with radionuclide measurements provided new insights into the evolution of the contamination with depth. Relationships between PAH concentrations and the distance to the potential sources were modelled. Despite both subcatchments are mainly rural, roadside areas appeared to concentrate 20% of the contamination inside the catchment while a local industry was found to be responsible for up to 30% of the stocks. Those results have important implications for understanding and controlling PAH contamination in rural areas of early-industrialized regions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Photoperiod cues and patterns of genetic variation limit phenological responses to climate change in warm parts of species' range: Modeling diameter-growth cessation in coast Douglas-fir.

PubMed

Ford, Kevin R; Harrington, Constance A; St Clair, J Bradley

2017-08-01

The phenology of diameter-growth cessation in trees will likely play a key role in mediating species and ecosystem responses to climate change. A common expectation is that warming will delay cessation, but the environmental and genetic influences on this process are poorly understood. We modeled the effects of temperature, photoperiod, and seed-source climate on diameter-growth-cessation timing in coast Douglas-fir (an ecologically and economically vital tree) using high-frequency growth measurements across broad environmental gradients for a range of genotypes from different seed sources. Our model suggests that cool temperatures or short photoperiods can induce cessation in autumn. At cool locations (high latitude and elevation), cessation seems to be induced primarily by low temperatures in early autumn (under relatively long photoperiods), so warming will likely delay cessation and extend the growing season. But at warm locations (low latitude or elevation), cessation seems to be induced primarily by short photoperiods later in autumn, so warming will likely lead to only slight extensions of the growing season, reflecting photoperiod limitations on phenological shifts. Trees from seed sources experiencing frequent frosts in autumn or early winter tended to cease growth earlier in the autumn, potentially as an adaptation to avoid frost. Thus, gene flow into populations in warm locations with little frost will likely have limited potential to delay mean cessation dates because these populations already cease growth relatively late. In addition, data from an abnormal heat wave suggested that very high temperatures during long photoperiods in early summer might also induce cessation. Climate change could make these conditions more common in warm locations, leading to much earlier cessation. Thus, photoperiod cues, patterns of genetic variation, and summer heat waves could limit the capacity of coast Douglas-fir to extend its growing season in response to climate change in the warm parts of its range. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

Probabilistic seismic hazard analysis for a nuclear power plant site in southeast Brazil

NASA Astrophysics Data System (ADS)

de Almeida, Andréia Abreu Diniz; Assumpção, Marcelo; Bommer, Julian J.; Drouet, Stéphane; Riccomini, Claudio; Prates, Carlos L. M.

2018-05-01

A site-specific probabilistic seismic hazard analysis (PSHA) has been performed for the only nuclear power plant site in Brazil, located 130 km southwest of Rio de Janeiro at Angra dos Reis. Logic trees were developed for both the seismic source characterisation and ground-motion characterisation models, in both cases seeking to capture the appreciable ranges of epistemic uncertainty with relatively few branches. This logic-tree structure allowed the hazard calculations to be performed efficiently while obtaining results that reflect the inevitable uncertainty in long-term seismic hazard assessment in this tectonically stable region. An innovative feature of the study is an additional seismic source zone added to capture the potential contributions of characteristics earthquake associated with geological faults in the region surrounding the coastal site.

The Last Arctic Sea Ice Refuge

NASA Astrophysics Data System (ADS)

Pfirman, S. L.; Tremblay, B.; Newton, R.; Fowler, C.

2010-12-01

Summer sea ice may persist along the northern flank of Canada and Greenland for decades longer than the rest of the Arctic, raising the possibility of a naturally formed refugium for ice-associated species. Observations and models indicate that some ice in this region forms locally, while some is transported to the area by winds and ocean currents. Depending on future changes in melt patterns and sea ice transport rates, both the central Arctic and Siberian shelf seas may be sources of ice to the region. An international system of monitoring and management of the sea ice refuge, along with the ice source regions, has the potential to maintain viable habitat for ice-associated species, including polar bears, for decades into the future. Issues to consider in developing a strategy include: + the likely duration and extent of summer sea ice in this region based on observations, models and paleoenvironmental information + the extent and characteristics of the “ice shed” contributing sea ice to the refuge, including its dynamics, physical and biological characteristics as well as potential for contamination from local or long-range sources + likely assemblages of ice-associated species and their habitats + potential stressors such as transportation, tourism, resource extraction, contamination + policy, governance, and development issues including management strategies that could maintain the viability of the refuge.

Using Unmanned Air Systems to Monitor Methane in the Atmosphere

NASA Technical Reports Server (NTRS)

Clow, Jacqueline; Smith, Jeremy Christopher

2016-01-01

Methane is likely to be an important contributor to global warming, and our current knowledge of its sources, distributions, and transport is insufficient. It is estimated that there could be from 7.5 to 400 billion tons carbon-equivalent of methane in the arctic region, a broad range that is indicative of the uncertainty within the Earth Science community. Unmanned Air Systems (UASs) are often used for combat or surveillance by the military, but they also have been used for Earth Science field missions. In this study, we will analyze the utility of the NASA Global Hawk and the Aurora Flight Sciences Orion UASs compared to the manned DC-8 aircraft for conducting a methane monitoring mission. The mission will focus on the measurement of methane along the boundaries of Arctic permafrost thaw and melting glaciers. The use of Long Endurance UAS brings a new range of possibilities including the ability to obtain long- term and persistent observations and to significantly augment methane measurements/retrievals collected by satellite. Furthermore, we discuss the future of long endurance UAS and their potential for science applications in the next twenty to twenty-five years.

Chameleon vector bosons

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

Nelson, Ann E.; Instituto de Fisica Teorica UAM/CSIC, Facultad de Ciencias, C-XVI Universidad Autonoma de Madrid Cantoblanco, Madrid 28049; Walsh, Jonathan

2008-05-01

We show that for a force mediated by a vector particle coupled to a conserved U(1) charge, the apparent range and strength can depend on the size and density of the source, and the proximity to other sources. This chameleon effect is due to screening from a light charged scalar. Such screening can weaken astrophysical constraints on new gauge bosons. As an example we consider the constraints on chameleonic gauged B-L. We show that although Casimir measurements greatly constrain any B-L force much stronger than gravity with range longer than 0.1 {mu}m, there remains an experimental window for a long-rangemore » chameleonic B-L force. Such a force could be much stronger than gravity, and long or infinite range in vacuum, but have an effective range near the surface of the earth which is less than a micron.« less

Long-period events and tremor at Popocatepetl volcano (1994-2000) and their broadband characteristics

USGS Publications Warehouse

Arciniega-Ceballos, A.; Chouet, B.; Dawson, P.

2003-01-01

Following an initial phreatic eruption on 21 December 1994, activity at Popocatepetl has been dominated by fumarolic emissions interspersed with more energetic emissions of ashes and gases. A phase of repetitive dome-building and dome-destroying episodes began in March 1996 and is still ongoing at present. We describe the long-period (LP) seismicity accompanying eruptive activity at Popocatepetl from December 1994 through May 2000, using data from a three-component broadband seismometer located 5 km from the summit crater. The broadband records display a variety of signals, with periods ranging in the band 0.04-90 s. Long-period events and tremor with typical dominant periods in the range 0.3-2.0 s are the most characteristic signals observed at Popocatepetl. These signals appear to reflect volumetric sources driven by pressure fluctuations associated with the unsteady transport of gases beneath the crater. Very-long-period (VLP) signals are also observed in association with LP events and tremor. The VLP signals which accompany LP events display Ricker-like wavelets with periods near 36 s, whereas VLP signals associated with tremor waveforms typically show sustained oscillations at periods ranging up to 90 s. The spectra and particle motion patterns remain similar from event to event for the majority of LP and tremor signals analyzed during the time span of this study, suggesting a repeated, non-destructive activation of a common source. Hypocenters determined by phase pick analyses of selected LP events recorded by the seven-station, permanent Popocatepetl short-period network suggest that the majority of these events are confined to a source region in the top 1.5 km below the crater floor. The repetitive occurrences of VLP signals with closely matched waveform characteristics are consistent with a non-destructive reactivation of at least two sources. One source appears to coincide with the main source region of LP seismicity, whereas the second is a deeper source whose activity appears to be intimately linked with episodes of monochromatic tremor.

Analysis of recordings from underwater controlled sources in the Pacific Ocean received by the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO)

NASA Astrophysics Data System (ADS)

Yamada, Tomoaki; Zampolli, Mario; Haralabus, Georgios; Heaney, Kevin; Prior, Mark; Isse, Takeshi

2016-04-01

Controlled impulsive scientific underwater sound sources in the Northwestern Pacific were observed at two IMS hydroacoustic stations in the Pacific Ocean. Although these experiments were conducted with the aim of studying the physical properties of the plate boundaries inside the Earth, they are also suitable for the investigation of long range underwater acoustic detections. In spite of the fact that the energy of these controlled impulsive scientific sources is significantly smaller than that of nuclear explosions, the signals were obtained by IMS hydrophone stations thousands of kilometres away and also by distant ocean bottom instruments operated by various Institutes, such as the Earthquake Research Institute, University of Tokyo. These experiments provide calibrated (yield, time, location) long-range acoustic transmissions, which enable one to examine the physics of long-range acoustic propagation and to verify the capabilities of the CTBTO IMS network to detect even small explosions.The two IMS stations used are H03 (Juan Fernandez Island, Chile) off the coast of Chile in the Southeastern Pacific and H11 (Wake Island, USA) in the Western Pacific. Both stations consist of two triplets of hydrophones in the SOFAR channel, which monitor the oceans for signs of nuclear explosions. H03 detected low-yield explosions above flat terrain at distances of 15,000 km across the Pacific as well as explosions above the landward slope off the coast of Japan at distances above 16,000 km across the Pacific. These records showed that source signatures, such as short duration and bubble pulses, were preserved over the long propagation distances. It was found that the observed maximum amplitudes from each source exhibit order of magnitude variations even when the yield and detonation depth are the same. The experimental data and transmission loss simulations suggest that bathymetric features around the sources and between the sources and the receivers are the main causes for these variations.

Anthropogenic organochlorine compounds as potential tracers for regional water masses: A case study of estuarine plume, coastal eddy, wind-driven upwelling and long-range warm current.

PubMed

Ya, Miaolei; Wu, Yuling; Li, Yongyu; Wang, Xinhong

2017-03-01

Water masses are the crucial factor driving the terrigenous anthropogenic organochlorine compounds (OCs) migration from the coast to open sea. Therefore, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were investigated in the Northern South China Sea (NSCS), where different types of water masses are generated by the East Asian summer monsoon: Pearl River estuary plume (PREP), Guangdong offshore eddy (GDEC), South China Sea warm current (SCSWC) and wind-driven upwelling current (WDUC). No discrepant distributions of OC concentrations were found in these water masses (p > 0.05). However, compositions and diagnostic ratios of HCHs, DDTs, trans- or cis-chlordane and PCBs could reflect the discrepancies in the input, transport and transformation of OCs caused by the hydrological characteristics of water masses, therefore, this allowing them to serve as potential tracers of regional water masses. In detail, α/γ-HCH and β-HCH percentages could indicate the weathered residue in the GDEC, long-range transport in the SCSWC, rapid photodegradation in the surface WDUC and biodegradation in the deep WDUC, respectively. The predominance of o, p'-DDT and p, p'-DDT could indicate fresh input in the PREP, GDEC and WDUC. DDT/DDTs of ratios <0.5 also reflected long-range transport in the SCSWC. Different DDD/DDE ratios indicated different oxygen environments of microbial degradation in the surface and deep water of the WDUC. Trans/cis-chlordane ratios could indicate the selective degradation of trans-chlordane in different water masses. Finally, a higher proportion of penta-PCB could reflect the strong paint additive sources carried by river erosion in the PREP. Copyright © 2016 Elsevier Ltd. All rights reserved.

Potential sources of bacteria colonizing the cryoconite of an Alpine glacier

PubMed Central

Franzetti, Andrea; Navarra, Federico; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Minora, Umberto; Azzoni, Roberto Sergio; Diolaiuti, Guglielmina; Smiraglia, Claudio

2017-01-01

We investigated the potential contribution of ice-marginal environments to the microbial communities of cryoconite holes, small depressions filled with meltwater that form on the surface of Forni Glacier (Italian Alps). Cryoconite holes are considered the most biologically active environments on glaciers. Bacteria can colonize these environments by short-range transport from ice-marginal environments or by long-range transport from distant areas. We used high throughput DNA sequencing to identify Operational Taxonomic Units (OTUs) present in cryoconite holes and three ice-marginal environments, the moraines, the glacier forefield, and a large (> 3 m high) ice-cored dirt cone occurring on the glacier surface. Bacterial communities of cryoconite holes were different from those of ice-marginal environments and hosted fewer OTUs. However, a network analysis revealed that the cryoconite holes shared more OTUs with the moraines and the dirt cone than with the glacier forefield. Ice-marginal environments may therefore act as sources of bacteria for cryoconite holes, but differences in environmental conditions limit the number of bacterial strains that may survive in them. At the same time, cryoconite holes host a few OTUs that were not found in any ice-marginal environment we sampled, thus suggesting that some bacterial populations are positively selected by the specific environmental conditions of the cryoconite holes. PMID:28358872

Potential sources of bacteria colonizing the cryoconite of an Alpine glacier.

PubMed

Franzetti, Andrea; Navarra, Federico; Tagliaferri, Ilario; Gandolfi, Isabella; Bestetti, Giuseppina; Minora, Umberto; Azzoni, Roberto Sergio; Diolaiuti, Guglielmina; Smiraglia, Claudio; Ambrosini, Roberto

2017-01-01

We investigated the potential contribution of ice-marginal environments to the microbial communities of cryoconite holes, small depressions filled with meltwater that form on the surface of Forni Glacier (Italian Alps). Cryoconite holes are considered the most biologically active environments on glaciers. Bacteria can colonize these environments by short-range transport from ice-marginal environments or by long-range transport from distant areas. We used high throughput DNA sequencing to identify Operational Taxonomic Units (OTUs) present in cryoconite holes and three ice-marginal environments, the moraines, the glacier forefield, and a large (> 3 m high) ice-cored dirt cone occurring on the glacier surface. Bacterial communities of cryoconite holes were different from those of ice-marginal environments and hosted fewer OTUs. However, a network analysis revealed that the cryoconite holes shared more OTUs with the moraines and the dirt cone than with the glacier forefield. Ice-marginal environments may therefore act as sources of bacteria for cryoconite holes, but differences in environmental conditions limit the number of bacterial strains that may survive in them. At the same time, cryoconite holes host a few OTUs that were not found in any ice-marginal environment we sampled, thus suggesting that some bacterial populations are positively selected by the specific environmental conditions of the cryoconite holes.

Controlling superconducting spin flow with a single homogeneous ferromagnet: interference, torque and spin-flip immunity

NASA Astrophysics Data System (ADS)

Jacobsen, Sol; Kulagina, Iryna; Linder, Jacob

Superconducting spintronics has the potential to overcome the Joule heating and short decay lengths of electron transport by harnessing the dissipationless spin currents of superconductors in thin-film devices. Using conventional singlet superconductive sources, such dissipationless currents have only been demonstrated experimentally using intricate magnetically inhomogeneous multilayers, which can be difficult to construct, control and measure. Here we present analytic and numerical results proving the possibility of both generating and controlling a long-ranged spin supercurrent using only one single homogeneous magnetic element (arXiv:1510.02488). The spin supercurrent generated in this way does not decay spatially, in stark contrast to normal spin currents that remain polarized only up to the spin relaxation length. Through a novel interference term between long-ranged and short-ranged Cooper pairs, we expose the existence of a superconductivity-mediated torque even without magnetic inhomogeneities, showing that the different components of the spin supercurrent polarization respond fundamentally differently to a change in the superconducting phase difference. This establishes a mechanism for tuning dissipationless spin and charge flow separately via superconductors. Supported by COST Action MP-1201 and RCN Grant Numbers 205591, 216700 and 24806.

The plant phenological online database (PPODB): an online database for long-term phenological data

NASA Astrophysics Data System (ADS)

Dierenbach, Jonas; Badeck, Franz-W.; Schaber, Jörg

2013-09-01

We present an online database that provides unrestricted and free access to over 16 million plant phenological observations from over 8,000 stations in Central Europe between the years 1880 and 2009. Unique features are (1) a flexible and unrestricted access to a full-fledged database, allowing for a wide range of individual queries and data retrieval, (2) historical data for Germany before 1951 ranging back to 1880, and (3) more than 480 curated long-term time series covering more than 100 years for individual phenological phases and plants combined over Natural Regions in Germany. Time series for single stations or Natural Regions can be accessed through a user-friendly graphical geo-referenced interface. The joint databases made available with the plant phenological database PPODB render accessible an important data source for further analyses of long-term changes in phenology. The database can be accessed via www.ppodb.de .

The Distributed Air Wing

DTIC Science & Technology

2014-06-01

Cruise Missile LCS Littoral Combat Ship LEO Low Earth Orbit LER Loss-Exchange-Ration LHA Landing Helicopter Assault LIDAR Laser Imaging Detection and...Ranging LOC Lines of Communication LP Linear Programming LRASM Long Range Anti-Ship Missile LT Long Ton MANA Map-Aware Non-uniform Automata ME...enemy’s spy satellites. Based on open source information, China currently has 25 satellites operating in Low Earth Orbit ( LEO ), each operates at an

Biomarkers in sedimentary sequences: Indicators to track sediment sources over decadal timescales

NASA Astrophysics Data System (ADS)

Chen, F. X.; Fang, N. F.; Wang, Y. X.; Tong, L. S.; Shi, Z. H.

2017-02-01

Long-term sedimentary sequence research can reveal how human activities and climate interact to affect catchment vegetation, flooding, soil erosion, and sediment sources. In this study, a biomarker sediment fingerprinting technique based on n-alkanes was used to identify long timescale (decadal) sediment sources in a small agricultural catchment. However, the highly saline carbonate environment and bacterial and algal activities elevated the levels of even-chain n-alkanes in the sediments, leading to an obvious even-over-odd predominance of short and middle components (C15-C26). Therefore, by analyzing three odd, long-chain n-alkanes (C27, C29 and C31) in 27 source samples from cropland, gully, and steep slope areas and one sediment sequence (one cultivated horizon and 47 flood couplets), a composite fingerprinting method and genetic algorithm optimization were applied to find the optimal source contributions to sediments. The biomarker fingerprinting results demonstrated that the primary sediment source is gullies, followed by cropland and steep slope areas. The average median source contributions associated with 47 flood couples collected from sediment core samples ranged from 0 ± 0.1% to 91.9 ± 0.4% with an average of 45.0% for gullies, 0 ± 0.4% to 95.6 ± 1.6% with an average of 38.2% for cropland, and 0 ± 2.1% to 60.7 ± 0.4% with an average of 16.8% for steep slopes. However, because farmers were highly motivated to manage the cropland after the 1980s, over half the sediments were derived from cropland in the 1980s. Biomarkers have significant advantages in the identification of sediments derived from different landscape units (e.g., gully and steep slope areas), and n-alkanes have considerable potential in high-resolution research of environmental change based on soil erosion in the hilly Loess Plateau region.

Do Firms Underinvest in Long-Term Research? Evidence from Cancer Clinical Trials.

PubMed

Budish, Eric; Roin, Benjamin N; Williams, Heidi

2015-07-01

We investigate whether private research investments are distorted away from long-term projects. Our theoretical model highlights two potential sources of this distortion: short-termism and the fixed patent term. Our empirical context is cancer research, where clinical trials--and hence, project durations--are shorter for late-stage cancer treatments relative to early-stage treatments or cancer prevention. Using newly constructed data, we document several sources of evidence that together show private research investments are distorted away from long-term projects. The value of life-years at stake appears large. We analyze three potential policy responses: surrogate (non-mortality) clinical-trial endpoints, targeted R&D subsidies, and patent design.

Do firms underinvest in long-term research? Evidence from cancer clinical trials

PubMed Central

Budish, Eric; Roin, Benjamin N.

2015-01-01

We investigate whether private research investments are distorted away from long-term projects. Our theoretical model highlights two potential sources of this distortion: short-termism and the fixed patent term. Our empirical context is cancer research, where clinical trials – and hence, project durations – are shorter for late-stage cancer treatments relative to early-stage treatments or cancer prevention. Using newly constructed data, we document several sources of evidence that together show private research investments are distorted away from long-term projects. The value of life-years at stake appears large. We analyze three potential policy responses: surrogate (non-mortality) clinicaltrial endpoints, targeted R&D subsidies, and patent design. PMID:26345455

Do firms underinvest in long-term research? Evidence from cancer clinical trials.

PubMed

Budish, Eric; Roin, Benjamin N; Williams, Heidi

2015-07-01

We investigate whether private research investments are distorted away from long-term projects. Our theoretical model highlights two potential sources of this distortion: short-termism and the fixed patent term. Our empirical context is cancer research, where clinical trials - and hence, project durations - are shorter for late-stage cancer treatments relative to early-stage treatments or cancer prevention. Using newly constructed data, we document several sources of evidence that together show private research investments are distorted away from long-term projects. The value of life-years at stake appears large. We analyze three potential policy responses: surrogate (non-mortality) clinicaltrial endpoints, targeted R&D subsidies, and patent design.

Do forests represent a long-term source of contaminated particulate matter in the Fukushima Prefecture?

PubMed

Laceby, J Patrick; Huon, Sylvain; Onda, Yuichi; Vaury, Veronique; Evrard, Olivier

2016-12-01

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in radiocesium fallout contaminating coastal catchments of the Fukushima Prefecture. As the decontamination effort progresses, the potential downstream migration of radiocesium contaminated particulate matter from forests, which cover over 65% of the most contaminated region, requires investigation. Carbon and nitrogen elemental concentrations and stable isotope ratios are thus used to model the relative contributions of forest, cultivated and subsoil sources to deposited particulate matter in three contaminated coastal catchments. Samples were taken from the main identified sources: cultivated (n = 28), forest (n = 46), and subsoils (n = 25). Deposited particulate matter (n = 82) was sampled during four fieldwork campaigns from November 2012 to November 2014. A distribution modelling approach quantified relative source contributions with multiple combinations of element parameters (carbon only, nitrogen only, and four parameters) for two particle size fractions (<63 μm and <2 mm). Although there was significant particle size enrichment for the particulate matter parameters, these differences only resulted in a 6% (SD 3%) mean difference in relative source contributions. Further, the three different modelling approaches only resulted in a 4% (SD 3%) difference between relative source contributions. For each particulate matter sample, six models (i.e. <63 μm and <2 mm from the three modelling approaches) were used to incorporate a broader definition of potential uncertainty into model results. Forest sources were modelled to contribute 17% (SD 10%) of particulate matter indicating they present a long term potential source of radiocesium contaminated material in fallout impacted catchments. Subsoils contributed 45% (SD 26%) of particulate matter and cultivated sources contributed 38% (SD 19%). The reservoir of radiocesium in forested landscapes in the Fukushima region represents a potential long-term source of particulate contaminated matter that will require diligent management for the foreseeable future. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tuning the effective fine structure constant in graphene: opposing effects of dielectric screening on short- and long-range potential scattering.

PubMed

Jang, C; Adam, S; Chen, J-H; Williams, E D; Das Sarma, S; Fuhrer, M S

2008-10-03

We reduce the dimensionless interaction strength alpha in graphene by adding a water overlayer in ultrahigh vacuum, thereby increasing dielectric screening. The mobility limited by long-range impurity scattering is increased over 30%, due to the background dielectric constant enhancement leading to a reduced interaction of electrons with charged impurities. However, the carrier-density-independent conductivity due to short-range impurities is decreased by almost 40%, due to reduced screening of the impurity potential by conduction electrons. The minimum conductivity is nearly unchanged, due to canceling contributions from the electron-hole puddle density and long-range impurity mobility. Experimental data are compared with theoretical predictions with excellent agreement.

Emerging Techniques for Vicarious Calibration of Visible Through Short Wave Infrared Remote Sensing Systems

NASA Technical Reports Server (NTRS)

Ryan, Robert E.

2006-01-01

Simple field-portable white light LED calibration source shows promise for visible range (420-750 nm) 1) Prototype demonstrated <0.5% drift over 10-40 C temperature range; 2) Additional complexity (more LEDs) will be necessary for extending spectral range into the NIR and SWIR; 3) LED long lifetimes should produce at least several hundreds of hours or more stability, minimizing need for expensive calibrations and supporting long-duration field campaigns; and 4) Enabling technology for developing autonomous sites.

Long-range dynamic polarization potentials for 11Be projectiles on 64Zn

NASA Astrophysics Data System (ADS)

So, W. Y.; Kim, K. S.; Choi, K. S.; Cheoun, Myung-Ki

2015-07-01

We investigate the effects of the long-range dynamic polarization (LRDP) potential, which consists of the Coulomb dipole excitation (CDE) potential and the long-range nuclear (LRN) potential, for the 11Be projectile on 64Zn. To study these effects, we perform a χ2 analysis of an optical model including the LRDP potential as well as a conventional short-range nuclear (SRN) potential. To take these effects into account, we argue that both the CDE and LRN potentials are essential to explaining the experimental values of PE, which is the ratio of the elastic scattering cross section to the Rutherford cross section. The Coulomb and nuclear parts of the LRDP potential are found to contribute to a strong absorption effect. Strong absorption occurs because the real part of the CDE and LRN potentials lowers the barrier, and the imaginary part of the CDE and LRN potentials removes the flux from the elastic channel in the 11Be+64Zn system. Finally, we extract the total reaction cross section σR including the inelastic, breakup, and fusion cross sections. The contribution of the inelastic scattering by the first excited state at ɛx1 st=0.32 MeV (1 /2-) is found to be relatively large and cannot be ignored. In addition, our results are shown to agree quite well with the experimental breakup reaction cross section by using a fairly large radius parameter.

Local chiral potentials with Δ -intermediate states and the structure of light nuclei

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

Piarulli, M.; Girlanda, L.; Schiavilla, R.

We present fully local versions of the minimally non-local nucleon-nucleon potentials constructed in a previous paper [M. Piarulli et al., Phys. Rev. C 91, 024003 (2015)], and use them in hypersperical-harmonics and quantum Monte Carlo calculations of ground and excited states of 3H, 3He, 4He, 6He, and 6Li nuclei. The long-range part of these local potentials includes oneand two-pion exchange contributions without and with Δ isobars in the intermediate states up to order Q3 (Q denotes generically the low momentum scale) in the chiral expansion, while the short-range part consists of contact interactions up to order Q4. The low-energy constantsmore » multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0–125 MeV or 0–200 MeV, and to the deuteron binding energy and nn singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutoffs, RL and RS respectively, ranging from (RL,RS) = (1.2, 0.8) fm down to (0.8, 0.6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.« less

Developing a protocol for long-term population monitoring and habitat projections for a climate-sensitive sentinel species to track ecosystem change and species range shifts

NASA Astrophysics Data System (ADS)

Beers, A.

2016-12-01

As a response to ongoing climate change, many species have started to shift their ranges poleward and toward higher elevations and mountain environments are predicted to experience especially rapid climatic changes. Because of this, there is likely a greater risk of habitat loss and local extinctions for species at high elevations compared to species at lower elevations. Among those potentially threatened habitat specialists is the American pika (Ochotona princeps), a climate sensitive indicator of climate change effects which may already be experiencing climate driven extirpations. Pikas are considered sentinels, indicators of greater ecosystem change. Changes in their distribution speaks to changes in availability of resources they require and shifts in the environment. Pika presence is closely tied to sub-surface ice features that act as a temperature buffer and water source. Those sub-surface ice features are critical in water cycling and long-term water storage and drive downstream hydrological and ecological processes. Understanding how this species responds to climate change therefore provides a model to inform landscape level conservation and management decisions. Pikas may be particularly vulnerable in parts of Colorado, including Rocky Mountain National Park (ROMO) and the Niwot Ridge LTER (NWT), where they may face population collapse as habitat suitability and connectivity both decline in response to various possible climate change scenarios, in large part because of cold stress and declining functional connectivity. Because of their potential role as an ecosystem indicator, their risk for decline, and how limitations to their survival likely vary across their range, management groups can use place based models of habitat suitability for pikas or other sentinel species in designing long term monitoring protocols to detect ecosystem responses to climate change. In this project we used remotely sensed data, occupancy surveys, and a random tessellation stratification to design a protocol for ROMO and NWT that best suits those environments. We also demonstrate the efficacy of habitat models based on remote sensing and their potential application toward tracking ecosystem change and species range shifts.

The influence of local oil exploration, regional wildfires, and long range transport on summer 2015 aerosol over the North Slope of Alaska

DOE PAGES

Creamean, Jessie M.; Maahn, Maximilian; de Boer, Gijs; ...

2017-07-06

The Arctic is warming at an alarming rate, yet the processes that contribute to enhanced warming are not well understood. Arctic aerosols have been targeted in studies for decades due to their consequential impacts on the energy budget directly and indirectly through their ability to modulate cloud microphysics. Even with the breadth of knowledge afforded from these previous studies, aerosols and their effects remain poorly quantified, especially in the rapidly-changing Arctic. Additionally, many previous studies involved use of ground-based measurements, and due to the frequent stratified nature of the Arctic atmosphere, brings into question the representativeness of these datasets aloft.more » Here, we report on airborne observations from the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program's Fifth Airborne Carbon Measurements (ACME-V) campaign along the North Slope of Alaska during the summer of 2015. Contrary to previous evidence that the Alaskan Arctic summertime air is relatively pristine, we show how local oil extraction activities, 2015’s central Alaskan wildfires, and to a lesser extent, long-range transport introduce aerosols and trace gases higher in concentration than previously reported in Arctic haze measurements to the North Slope. Although these sources were either episodic or localized, they serve as abundant aerosol sources that have the potential to impact a larger spatial scale after emission.« less

High-level exposure to lithium, boron, cesium, and arsenic via drinking water in the Andes of northern Argentina.

PubMed

Concha, Gabriela; Broberg, Karin; Grandér, Margaretha; Cardozo, Alejandro; Palm, Brita; Vahter, Marie

2010-09-01

Elevated concentrations of arsenic in drinking water are common worldwide, however, little is known about the presence of other potentially toxic elements. We analyzed 31 different elements in drinking water collected in San Antonio de los Cobres and five surrounding Andean villages in Argentina, and in urine of the inhabitants, using ICP-MS. Besides confirmation of elevated arsenic concentrations in the drinking water (up to 210 microg/L), we found remarkably high concentrations of lithium (highest 1000 microg/L), cesium (320 microg/L), rubidium (47 microg/L), and boron (5950 microg/L). Similarly elevated concentrations of arsenic, lithium, cesium, and boron were found in urine of the studied women (N=198): village median values ranged from 26 to 266 microg/L of arsenic, 340 to 4550 microg/L of lithium, 34 to 531 microg/L of cesium, and 2980 to 16,560 microg/L of boron. There is an apparent risk of toxic effects of long-term exposure to several of the elements, and studies on associations with adverse human health effects are warranted, particularly considering the combined, life-long exposure. Because of the observed wide range of concentrations, all water sources used for drinking water should be screened for a large number of elements; obviously, this applies to all drinking water sources globally.

The influence of local oil exploration, regional wildfires, and long range transport on summer 2015 aerosol over the North Slope of Alaska

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

Creamean, Jessie M.; Maahn, Maximilian; de Boer, Gijs

The Arctic is warming at an alarming rate, yet the processes that contribute to enhanced warming are not well understood. Arctic aerosols have been targeted in studies for decades due to their consequential impacts on the energy budget directly and indirectly through their ability to modulate cloud microphysics. Even with the breadth of knowledge afforded from these previous studies, aerosols and their effects remain poorly quantified, especially in the rapidly-changing Arctic. Additionally, many previous studies involved use of ground-based measurements, and due to the frequent stratified nature of the Arctic atmosphere, brings into question the representativeness of these datasets aloft.more » Here, we report on airborne observations from the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program's Fifth Airborne Carbon Measurements (ACME-V) campaign along the North Slope of Alaska during the summer of 2015. Contrary to previous evidence that the Alaskan Arctic summertime air is relatively pristine, we show how local oil extraction activities, 2015’s central Alaskan wildfires, and to a lesser extent, long-range transport introduce aerosols and trace gases higher in concentration than previously reported in Arctic haze measurements to the North Slope. Although these sources were either episodic or localized, they serve as abundant aerosol sources that have the potential to impact a larger spatial scale after emission.« less

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

Oryu, S.; Nishinohara, S.; Sonoda, K.

The three-charged-particle Faddeev-type equations for a full potential system are presented in momentum space. The potential is composed of a short range two-body, nuclear potential and a three-body-force potential plus the long range Coulomb potential. A novel framework is proposed for this purpose which contains two innovations aimed at realizing a breakthrough for the notoriously troublesome long range behavior of charged particle systems and tedious Coulomb prescriptions in momentum space calculations. One involves introduction of a Coulomb boundary condition and the other is a new definition of the Coulomb amplitude using two-potential theory for VC = VR + V{phi} withmore » respect to a screened Coulomb potential VR and the remainder V{phi} = VC - VR. Some important equations, which are underlined in our approach, are mathematically proved. The formulation is not only rigorous but also useful for numerical calculations.« less

Impacts of land cover data selection and trait parameterisation on dynamic modelling of species' range expansion.

PubMed

Heikkinen, Risto K; Bocedi, Greta; Kuussaari, Mikko; Heliölä, Janne; Leikola, Niko; Pöyry, Juha; Travis, Justin M J

2014-01-01

Dynamic models for range expansion provide a promising tool for assessing species' capacity to respond to climate change by shifting their ranges to new areas. However, these models include a number of uncertainties which may affect how successfully they can be applied to climate change oriented conservation planning. We used RangeShifter, a novel dynamic and individual-based modelling platform, to study two potential sources of such uncertainties: the selection of land cover data and the parameterization of key life-history traits. As an example, we modelled the range expansion dynamics of two butterfly species, one habitat specialist (Maniola jurtina) and one generalist (Issoria lathonia). Our results show that projections of total population size, number of occupied grid cells and the mean maximal latitudinal range shift were all clearly dependent on the choice made between using CORINE land cover data vs. using more detailed grassland data from three alternative national databases. Range expansion was also sensitive to the parameterization of the four considered life-history traits (magnitude and probability of long-distance dispersal events, population growth rate and carrying capacity), with carrying capacity and magnitude of long-distance dispersal showing the strongest effect. Our results highlight the sensitivity of dynamic species population models to the selection of existing land cover data and to uncertainty in the model parameters and indicate that these need to be carefully evaluated before the models are applied to conservation planning.

Atmospheric transport of radioactive debris to Norway in case of a hypothetical accident related to the recovery of the Russian submarine K-27.

PubMed

Bartnicki, Jerzy; Amundsen, Ingar; Brown, Justin; Hosseini, Ali; Hov, Øystein; Haakenstad, Hilde; Klein, Heiko; Lind, Ole Christian; Salbu, Brit; Szacinski Wendel, Cato C; Ytre-Eide, Martin Album

2016-01-01

The Russian nuclear submarine K-27 suffered a loss of coolant accident in 1968 and with nuclear fuel in both reactors it was scuttled in 1981 in the outer part of Stepovogo Bay located on the eastern coast of Novaya Zemlya. The inventory of spent nuclear fuel on board the submarine is of concern because it represents a potential source of radioactive contamination of the Kara Sea and a criticality accident with potential for long-range atmospheric transport of radioactive particles cannot be ruled out. To address these concerns and to provide a better basis for evaluating possible radiological impacts of potential releases in case a salvage operation is initiated, we assessed the atmospheric transport of radionuclides and deposition in Norway from a hypothetical criticality accident on board the K-27. To achieve this, a long term (33 years) meteorological database has been prepared and used for selection of the worst case meteorological scenarios for each of three selected locations of the potential accident. Next, the dispersion model SNAP was run with the source term for the worst-case accident scenario and selected meteorological scenarios. The results showed predictions to be very sensitive to the estimation of the source term for the worst-case accident and especially to the sizes and densities of released radioactive particles. The results indicated that a large area of Norway could be affected, but that the deposition in Northern Norway would be considerably higher than in other areas of the country. The simulations showed that deposition from the worst-case scenario of a hypothetical K-27 accident would be at least two orders of magnitude lower than the deposition observed in Norway following the Chernobyl accident. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Light Emitting Diode Flashlights as Effective and Inexpensive Light Sources for Fluorescence Microscopy

PubMed Central

Robertson, J. Brian; Zhang, Yunfei; Johnson, Carl Hirschie

2009-01-01

Summary Light-emitting diodes (LEDs) are becoming more commonly used as light sources for fluorescence microscopy. We describe the adaptation of a commercially available LED flashlight for use as a source for fluorescence excitation. This light source is long-lived, inexpensive, and is effective for excitation in the range of 440–600 nm. PMID:19772530

The impact of flow focusing on gas hydrate accumulations in overpressured marine sediments

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

Nole, Michael; Daigle, Hugh; Cook, Ann

This study demonstrates the potential for flow focusing due to overpressuring in marine sedimentary environments to act as a significant methane transport mechanism from which methane hydrate can precipitate in large quantities in dipping sandstone bodies. Traditionally, gas hydrate accumulations in nature are discussed as resulting from either short-range diffusive methane migration or from long-range advective fluid transport sourced from depth. However, 3D simulations performed in this study demonstrate that a third migration mechanism, short-range advective transport, can provide a significant methane source that is unencumbered by limitations of the other two end-member mechanisms. Short-range advective sourcing is advantageous overmore » diffusion because it can convey greater amounts of methane to sands over shorter timespans, yet it is not necessarily limited by down-dip pore blocking in sands as is typical of updip advection from a deep source. These results are novel because they integrate pore size impacts on spatial solubility gradients, grid block properties that evolve through time, and methane sourcing through microbial methanogenesis into a holistic characterization of environments exposed to multiple methane hydrate sourcing mechanisms. We show that flow focusing toward sand bodies transports large quantities of methane, the magnitude of which are determined by the sand-clay solubility contrast, and generates larger quantities of hydrate in sands than a solely diffusive system; after depositing methane as hydrate, fluid exiting a sand body is depleted in methane and leaves a hydrate free region in its wake above the sand. Additionally, we demonstrate that in overpressured environments, hydrate growth is initially diffusively dominated before transitioning to an advection-dominated regime. The timescale and depth at which this transition takes place depends primarily on the rate of microbial metabolism and the sedimentation rate but only depends loosely on the degree of overpressuring.« less

Adjustable long duration high-intensity point light source

NASA Astrophysics Data System (ADS)

Krehl, P.; Hagelweide, J. B.

1981-06-01

A new long duration high-intensity point light source with adjustable light duration and a small light spot locally stable in time has been developed. The principle involved is a stationary high-temperature plasma flow inside a partly constrained capillary of a coaxial spark gap which is viewed end on through a terminating Plexiglas window. The point light spark gap is operated via a resistor by an artificial transmission line. Using two exchangeable inductance sets in the line, two ranges of photoduration 10-130 μs and 100-600 μs can be covered. For a light spot size of 1.5 mm diameter the corresponding peak light output amounts to 5×106 and 1.6×106 candelas, respectively. Within these ranges the duration is controlled by an ignitron crowbar to extinguish the plasma. The adjustable photoduration is very useful for the application of continuous writing rotating mirror cameras, thus preventing multiple exposures. The essentially uniform exposure within the visible spectral range makes the new light source suitable for color cinematography.

Organic Tracers from Asphalt in Propolis Produced by Urban Honey Bees, Apis mellifera Linn.

PubMed

Alqarni, Abdulaziz S; Rushdi, Ahmed I; Owayss, Ayman A; Raweh, Hael S; El-Mubarak, Aarif H; Simoneit, Bernd R T

2015-01-01

Propolis is a gummy material produced by honey bees to protect their hives and currently has drawn the attention of researchers due to its broad clinical use. It has been reported, based only on observations, that honey bees also collect other non-vegetation substances such as paint or asphalt/tar to make propolis. Therefore, propolis samples were collected from bee hives in Riyadh and Al-Bahah, a natural area, Saudi Arabia to determine their compositional characteristics and possible sources of the neutral organic compounds. The samples were extracted with hexane and analyzed by gas chromatography-mass spectrometry. The results showed that the major compounds were n-alkanes, n-alkenes, methyl n-alkanoates, long chain wax esters, triterpenoids and hopanes. The n-alkanes (ranging from C17 to C40) were significant with relative concentrations varying from 23.8 to 56.8% (mean = 44.9+9.4%) of the total extracts. Their odd carbon preference index (CPI) ranged from 3.6 to 7.7, with a maximum concentration at heptacosane indicating inputs from higher plant vegetation wax. The relative concentrations of the n-alkenes varied from 23.8 to 41.19% (mean = 35.6+5.1%), with CPI = 12.4-31.4, range from C25 to C35 and maximum at tritriacontane. Methyl n-alkanoates, ranged from C12 to C26 as acids, with concentrations from 3.11 to 33.2% (mean = 9.6+9.5%). Long chain wax esters and triterpenoids were minor. The main triterpenoids were α- and β-amyrins, amyrones and amyryl acetates. The presence of hopanes in some total extracts (up to 12.5%) indicated that the bees also collected petroleum derivatives from vicinal asphalt and used that as an additional ingredient to make propolis. Therefore, caution should be taken when considering the chemical compositions of propolis as potential sources of natural products for biological and pharmacological applications. Moreover, beekeepers should be aware of the proper source of propolis in the flight range of their bee colonies.

Organic Tracers from Asphalt in Propolis Produced by Urban Honey Bees, Apis mellifera Linn.

PubMed Central

Alqarni, Abdulaziz S.; Rushdi, Ahmed I.; Owayss, Ayman A.; Raweh, Hael S.; El-Mubarak, Aarif H.; Simoneit, Bernd R. T.

2015-01-01

Propolis is a gummy material produced by honey bees to protect their hives and currently has drawn the attention of researchers due to its broad clinical use. It has been reported, based only on observations, that honey bees also collect other non-vegetation substances such as paint or asphalt/tar to make propolis. Therefore, propolis samples were collected from bee hives in Riyadh and Al-Bahah, a natural area, Saudi Arabia to determine their compositional characteristics and possible sources of the neutral organic compounds. The samples were extracted with hexane and analyzed by gas chromatography-mass spectrometry. The results showed that the major compounds were n-alkanes, n-alkenes, methyl n-alkanoates, long chain wax esters, triterpenoids and hopanes. The n-alkanes (ranging from C17 to C40) were significant with relative concentrations varying from 23.8 to 56.8% (mean = 44.9+9.4%) of the total extracts. Their odd carbon preference index (CPI) ranged from 3.6 to 7.7, with a maximum concentration at heptacosane indicating inputs from higher plant vegetation wax. The relative concentrations of the n-alkenes varied from 23.8 to 41.19% (mean = 35.6+5.1%), with CPI = 12.4-31.4, range from C25 to C35 and maximum at tritriacontane. Methyl n-alkanoates, ranged from C12 to C26 as acids, with concentrations from 3.11 to 33.2% (mean = 9.6+9.5%). Long chain wax esters and triterpenoids were minor. The main triterpenoids were α- and β-amyrins, amyrones and amyryl acetates. The presence of hopanes in some total extracts (up to 12.5%) indicated that the bees also collected petroleum derivatives from vicinal asphalt and used that as an additional ingredient to make propolis. Therefore, caution should be taken when considering the chemical compositions of propolis as potential sources of natural products for biological and pharmacological applications. Moreover, beekeepers should be aware of the proper source of propolis in the flight range of their bee colonies. PMID:26075382

Role of genomics and transcriptomics in selection of reintroduction source populations.

PubMed

He, Xiaoping; Johansson, Mattias L; Heath, Daniel D

2016-10-01

The use and importance of reintroduction as a conservation tool to return a species to its historical range from which it has been extirpated will increase as climate change and human development accelerate habitat loss and population extinctions. Although the number of reintroduction attempts has increased rapidly over the past 2 decades, the success rate is generally low. As a result of population differences in fitness-related traits and divergent responses to environmental stresses, population performance upon reintroduction is highly variable, and it is generally agreed that selecting an appropriate source population is a critical component of a successful reintroduction. Conservation genomics is an emerging field that addresses long-standing challenges in conservation, and the potential for using novel molecular genetic approaches to inform and improve conservation efforts is high. Because the successful establishment and persistence of reintroduced populations is highly dependent on the functional genetic variation and environmental stress tolerance of the source population, we propose the application of conservation genomics and transcriptomics to guide reintroduction practices. Specifically, we propose using genome-wide functional loci to estimate genetic variation of source populations. This estimate can then be used to predict the potential for adaptation. We also propose using transcriptional profiling to measure the expression response of fitness-related genes to environmental stresses as a proxy for acclimation (tolerance) capacity. Appropriate application of conservation genomics and transcriptomics has the potential to dramatically enhance reintroduction success in a time of rapidly declining biodiversity and accelerating environmental change. © 2016 Society for Conservation Biology.

Quantifying and characterizing boreal headwater NOM using hydrological understanding, absorbance spectroscopy, and fluorescence techniques

NASA Astrophysics Data System (ADS)

Ledesma, José; Köhler, Stephan; Grabs, Thomas; Bishop, Kevin; Kothawala, Dolly; Schiff, Sherry; Futter, Martyn

2017-04-01

Boreal forests store large amounts of carbon, especially in headwater terrestrial-aquatic interfaces dominated by OM-rich riparian zones (RZs). Thus, RZs are the main source of natural organic matter (NOM) in boreal surface waters. We hydrologically illustrated that the transfer of substances, including NOM, from RZs to streams is dominated by a narrow depth range with the highest contribution to solute and water fluxes, the so-called dominant source layer (DSL). By comparing the size of potential sources in relation to lateral fluxes in the DSL in several RZs within a Swedish boreal catchment, we demonstrated that there is a potential long-lasting supply of NOM from these RZ into the stream. This was supported by rough estimates of primary production and 14C measurements, which indicated that modern carbon is the predominant fraction exported. Despite the overwhelming quantitative evidence that RZs are the source of NOM to boreal streams, few studies have compared NOM quality in streams, RZs, and upslope areas. Using absorbance indicators and fluorescence techniques we showed that the NOM character in several RZ sampling sites resembles that of the corresponding streams and differs from that of the upslope soils. Given that forecast future climate in the boreal region and depletion of sulfur pools are expected to increase NOM in aquatic systems, potentially disrupting water quality and the global carbon cycle, is critical to integrate quantitative and qualitative approaches to understand OM cycling in boreal RZs.

Tropospheric ozone maxima observed over the Arabian Sea during the pre-monsoon

NASA Astrophysics Data System (ADS)

Jia, Jia; Ladstätter-Weißenmayer, Annette; Hou, Xuewei; Rozanov, Alexei; Burrows, John P.

2017-04-01

An enhancement of the tropospheric ozone column (TOC) over Arabian Sea (AS) during the pre-monsoon season is reported in this study. The potential sources of the AS spring ozone pool are investigated by use of multiple data sets (e.g., SCIAMACHY Limb-Nadir-Matching TOC, OMI/MLS TOC, TES TOC, MACC reanalysis data, MOZART-4 model and HYSPLIT model). Three-quarters of the enhanced ozone concentrations are attributed to the 0-8 km height range. The main source of the ozone enhancement is considered to be caused by long-range transport of ozone pollutants from India (˜ 50 % contributions to the lowest 4 km, ˜ 20 % contributions to the 4-8 km height range), the Middle East, Africa and Europe (˜ 30 % in total). In addition, the vertical pollution accumulation in the lower troposphere, especially at 4-8 km, was found to be important for the AS spring ozone pool formation. Local photochemistry, on the other hand, plays a negligible role in producing ozone at the 4-8 km height range. In the 0-4 km height range, ozone is quickly removed by wet deposition. The AS spring TOC maxima are influenced by the dynamical variations caused by the sea surface temperature (SST) anomaly during the El Niño period in 2005 and 2010 with a ˜ 5 DU decrease.

Long-range transport and mixing of aerosol sources during the 2013 North American biomass burning episode: analysis of multiple lidar observations in the western Mediterranean basin

NASA Astrophysics Data System (ADS)

Ancellet, Gerard; Pelon, Jacques; Totems, Julien; Chazette, Patrick; Bazureau, Ariane; Sicard, Michaël; Di Iorio, Tatiana; Dulac, Francois; Mallet, Marc

2016-04-01

Long-range transport of biomass burning (BB) aerosols between North America and the Mediterranean region took place in June 2013. A large number of ground-based and airborne lidar measurements were deployed in the western Mediterranean during the Chemistry-AeRosol Mediterranean EXperiment (ChArMEx) intensive observation period. A detailed analysis of the potential North American aerosol sources is conducted including the assessment of their transport to Europe using forward simulations of the FLEXPART Lagrangian particle dispersion model initialized using satellite observations by MODIS and CALIOP. The three-dimensional structure of the aerosol distribution in the ChArMEx domain observed by the ground-based lidars (Minorca, Barcelona and Lampedusa), a Falcon-20 aircraft flight and three CALIOP tracks, agrees very well with the model simulation of the three major sources considered in this work: Canadian and Colorado fires, a dust storm from western US and the contribution of Saharan dust streamers advected from the North Atlantic trade wind region into the westerlies region. Four aerosol types were identified using the optical properties of the observed aerosol layers (aerosol depolarization ratio, lidar ratio) and the transport model analysis of the contribution of each aerosol source: (i) pure BB layer, (ii) weakly dusty BB, (iii) significant mixture of BB and dust transported from the trade wind region, and (iv) the outflow of Saharan dust by the subtropical jet and not mixed with BB aerosol. The contribution of the Canadian fires is the major aerosol source during this episode while mixing of dust and BB is only significant at an altitude above 5 km. The mixing corresponds to a 20-30 % dust contribution in the total aerosol backscatter. The comparison with the MODIS aerosol optical depth horizontal distribution during this episode over the western Mediterranean Sea shows that the Canadian fire contributions were as large as the direct northward dust outflow from Sahara.

Long range transport and mixing of aerosol sources during the 2013 North American biomass burning episode: analysis of multiple lidar observations in the Western Mediterranean basin

NASA Astrophysics Data System (ADS)

Ancellet, G.; Pelon, J.; Totems, J.; Chazette, P.; Bazureau, A.; Sicard, M.; Di Iorio, T.; Dulac, F.; Mallet, M.

2015-11-01

Long range transport of biomass burning (BB) aerosols between North America and the Mediterranean region took place in June 2013. A large number of ground based and airborne lidar measurements were deployed in the Western Mediterranean during the Chemistry-AeRosol Mediterranean EXperiment (ChArMEx) intensive observation period. A detailed analysis of the potential North American aerosol sources is conducted including the assessment of their transport to Europe using forward simulations of the FLEXPART Lagrangian particle dispersion model initialized using satellite observations by MODIS and CALIOP. The three dimensional structure of the aerosol distribution in the ChArMEx domain observed by the ground-based lidars (Menorca, Barcelona and Lampedusa), a Falcon-20 aircraft flight and three CALIOP tracks, agree very well with the model simulation of the three major sources considered in this work: Canadian and Colorado fires, a dust storm from Western US and the contribution of Saharan dust streamers advected from the North Atlantic trade wind region into the Westerlies region. Four aerosol types were identified using the optical properties of the observed aerosol layers (aerosol depolarization ratio, lidar ratio) and the transport model analysis of the contribution of each aerosol source: (I) pure BB layer, (II) weakly dusty BB, (III) significant mixture of BB and dust transported from the trade wind region (IV) the outflow of Saharan dust by the subtropical jet and not mixed with BB aerosol. The contribution of the Canadian fires is the major aerosol source during this episode while mixing of dust and BB is only significant at altitude above 5 km. The mixing corresponds to a 20-30 % dust contribution in the total aerosol backscatter. The comparison with the MODIS AOD horizontal distribution during this episode over the Western Mediterranean sea shows that the Canadian fires contribution were as large as the direct northward dust outflow from Sahara.

Bio-Inspired Extreme Wetting Surfaces for Biomedical Applications

PubMed Central

Shin, Sera; Seo, Jungmok; Han, Heetak; Kang, Subin; Kim, Hyunchul; Lee, Taeyoon

2016-01-01

Biological creatures with unique surface wettability have long served as a source of inspiration for scientists and engineers. More specifically, materials exhibiting extreme wetting properties, such as superhydrophilic and superhydrophobic surfaces, have attracted considerable attention because of their potential use in various applications, such as self-cleaning fabrics, anti-fog windows, anti-corrosive coatings, drag-reduction systems, and efficient water transportation. In particular, the engineering of surface wettability by manipulating chemical properties and structure opens emerging biomedical applications ranging from high-throughput cell culture platforms to biomedical devices. This review describes design and fabrication methods for artificial extreme wetting surfaces. Next, we introduce some of the newer and emerging biomedical applications using extreme wetting surfaces. Current challenges and future prospects of the surfaces for potential biomedical applications are also addressed. PMID:28787916

Using Redwood Tree Ring Chronologies to Obtain the Long-View on California's Coastal Climate

NASA Astrophysics Data System (ADS)

Dawson, T. E.; Roden, J. S.; Voelker, S. L.; Johnstone, J. A.; Ambrose, A.

2014-12-01

Coast redwood (Sequoia sempervirens) occupies a long and narrow range at the land-sea interface from the southern Big Bur region to the California-Oregon boarder. Since mature trees can live in excess of 2000 years, using the interannual variability in the oxygen and carbon stable isotope composition of tree rings obtained from trees growing in different parts of the redwood range holds the potential for obtaining a long-term record of California's coastal climate, including the history of temperatures, low cloud / fog, rainfall and associated climatic drivers of their variation. We analyzed the oxygen and carbon stable isotope composition of tree ring cellulose from both tree cores and whole cross-sectional slabs and compared these data to several regional climate indicies and to published growth chronologies to obtain the long-view on California's coastal climate. Several highlights will be presented and discussed. These include: (1) redwoods faithfully record water sources they use in the oxygen stable isotope composition of their tree ring cellulose; (2) these is both strong watershed- and regional-scale coherence; (3) redwood tree ring carbon isotope composition shows its strongest correlations to tree water status, stand-scale humidity, and at the regional scale to what we term "summer precipitation" anomalies (lack of rain with presence of fog); also (4) that carbon stable isotope composition is very sensitive to within tree and stand microclimate while oxygen stable isotope composition seems to be sensitive to topographic site factors like slope position and proximity to riparian / gully habitats; (5) multivariate climatic analyses reveal that summertime drought recorded in the isotope excursions are most strongly linked to atmospheric circulation anomalies; and (6) that redwood tree rings and their isotope composition provide great potential for reconstructing high-resolution paleo-climate along the California coast.

A study of impact of Asian dusts and their transport pathways to Hong Kong using multiple AERONET data, trajectory, and in-situ measurements

NASA Astrophysics Data System (ADS)

Wong, Man Sing; Nichol, Janet Elizabeth; Lee, Kwon Ho

2010-10-01

Hong Kong, a commercial and financial city located in south-east China has suffered serious air pollution for the last decade due largely to rapid urban and industrial expansion of the cities of mainland China. However, the potential sources and pathways of aerosols transported to Hong Kong have not been well researched due to the lack of air quality monitoring stations in southern China. Here, an integrated method combining the AErosol RObotic NETwork (AERONET) data, trajectory and Potential Source Contribution Function (PSCF) modeling is used to identify the potential transport pathways and contribution of sources from four characteristic aerosol types. Four characteristic aerosol types were defined using a total of 730 AERONET data measurements between 2005 and 2008. They are coastal urban, polluted urban, dust (likely to be long distance desert dust), and heavy pollution. Results show that the sources of polluted urban and heavy pollution are associated with industrial emissions in southern China, whereas coastal urban aerosols have been affected both from natural marine aerosol and emissions. The PSCF map of dust shows a wide range of pathways followed by east- and south-eastwards trajectories from northwest China to Hong Kong. Although the contribution from dust sources is small compared to the anthropogenic aerosols, a serious recent dust outbreak has been observed in Hong Kong with an elevation of the Air Pollution Index to 500, compared with 50-100 on normal days. Therefore, the combined use of clustered AERONET data, trajectory and the PSCF models can help to resolve the longstanding issue about source regions and characteristics of pollutants carried to Hong Kong.

Ambient PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in Changhua County, central Taiwan: Seasonal variation, source apportionment and cancer risk assessment.

PubMed

Chen, Yu-Cheng; Chiang, Hung-Che; Hsu, Chin-Yu; Yang, Tzu-Ting; Lin, Tzu-Yu; Chen, Mu-Jean; Chen, Nai-Tzu; Wu, Yuh-Shen

2016-11-01

This study investigates PM 2.5 -bound PAHs for rural sites (Dacheng and Fangyuan) positioned close to heavy air-polluting industries in Changhua County, central Taiwan. A total of 113 PM 2.5 samples with 22 PAHs collected from 2014 to 2015 were analyzed, and Positive Matrix Factorization (PMF) and diagnostic ratios of PAHs were applied to quantify potential PAH sources. The influences of local and regional sources were also explored using the conditional probability function (CPF) and potential source contribution function (PSCF) with PMF-modeled results, respectively. Annual mean concentrations of total PAHs were 2.91 ± 1.34 and 3.04 ± 1.40 ng/m 3 for Dacheng and Fangyuan, respectively, and their corresponding BaP eq were measured at 0.534 ± 0.255 and 0.563 ± 0.273 ng/m 3 in concentration. Seasonal variations with higher PAHs found for the winter than for the spring and summer were observed for both sites. The lifetime excess cancer risk (ECR) from inhalation exposure to PAHs was recorded as 4.7 × 10 -5 overall. Potential sources of PM 2.5 -bound PAHs include unburned petroleum and traffic emissions (42%), steel industry and coal combustion (31%), and petroleum and oil burning (27%), and unburned petroleum and traffic emission could contribute the highest ECR (2.4 × 10 -5 ). The CPF results show that directional apportionment patterns were consistent with the actual locations of local PAH sources. The PSCF results indicate that mainly northeastern regions of China have contributed elevated PM 2.5 -bound PAHs from long-range transports. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sources and Deposition of Polycyclic Aromatic Hydrocarbons to Western U.S. National Parks

PubMed Central

USENKO, SASCHA; MASSEY SIMONICH, STACI L.; HAGEMAN, KIMBERLY J.; SCHRLAU, JILL E.; GEISER, LINDA; CAMPBELL, DON H.; APPLEBY, PETER G.; LANDERS, DIXON H.

2010-01-01

Seasonal snowpack, lichens, and lake sediment cores were collected from fourteen lake catchments in eight western U.S. National Parks and analyzed for sixteen polycyclic aromatic hydrocarbons (PAHs) in order to determine their current and historical deposition, as well as to identify their potential sources. Seasonal snowpack was measured to determine the current wintertime atmospheric PAH deposition; lichens were measured to determine the long-term, year around deposition; and the temporal PAH deposition trends were reconstructed using lake sediment cores dated using 210Pb and 137Cs. The fourteen remote lake catchments ranged from low-latitude catchments (36.6° N) at high elevation (2900 masl) in Sequoia National Park, CA to high-latitude catchments (68.4° N) at low elevation (427 masl) in the Alaskan Arctic. Over 75% of the catchments demonstrated statistically significant temporal trends in ΣPAH sediment flux, depending on catchment proximity to source regions and topographic barriers. The ΣPAH concentrations and fluxes in seasonal snowpack, lichens, and surficial sediment were 3.6 to 60,000 times greater in the Snyder Lake catchment of Glacier National Park than the other 13 lake catchments. The PAH ratios measured in snow, lichen, and sediment were used to identify a local aluminum smelter as a major source of PAHs to the Snyder Lake catchment. These results suggest that topographic barriers influence the atmospheric transport and deposition of PAHs in high-elevation ecosystems and that PAH sources to these national park ecosystems range from local point sources to diffuse regional and global sources. PMID:20465303

Broadband classification and statistics of echoes from aggregations of fish measured by long-range, mid-frequency sonar.

PubMed

Jones, Benjamin A; Stanton, Timothy K; Colosi, John A; Gauss, Roger C; Fialkowski, Joseph M; Michael Jech, J

2017-06-01

For horizontal-looking sonar systems operating at mid-frequencies (1-10 kHz), scattering by fish with resonant gas-filled swimbladders can dominate seafloor and surface reverberation at long-ranges (i.e., distances much greater than the water depth). This source of scattering, which can be difficult to distinguish from other sources of scattering in the water column or at the boundaries, can add spatio-temporal variability to an already complex acoustic record. Sparsely distributed, spatially compact fish aggregations were measured in the Gulf of Maine using a long-range broadband sonar with continuous spectral coverage from 1.5 to 5 kHz. Observed echoes, that are at least 15 decibels above background levels in the horizontal-looking sonar data, are classified spectrally by the resonance features as due to swimbladder-bearing fish. Contemporaneous multi-frequency echosounder measurements (18, 38, and 120 kHz) and net samples are used in conjunction with physics-based acoustic models to validate this approach. Furthermore, the fish aggregations are statistically characterized in the long-range data by highly non-Rayleigh distributions of the echo magnitudes. These distributions are accurately predicted by a computationally efficient, physics-based model. The model accounts for beam-pattern and waveguide effects as well as the scattering response of aggregations of fish.

Low cost and open source multi-fluorescence imaging system for teaching and research in biology and bioengineering.

PubMed

Nuñez, Isaac; Matute, Tamara; Herrera, Roberto; Keymer, Juan; Marzullo, Timothy; Rudge, Timothy; Federici, Fernán

2017-01-01

The advent of easy-to-use open source microcontrollers, off-the-shelf electronics and customizable manufacturing technologies has facilitated the development of inexpensive scientific devices and laboratory equipment. In this study, we describe an imaging system that integrates low-cost and open-source hardware, software and genetic resources. The multi-fluorescence imaging system consists of readily available 470 nm LEDs, a Raspberry Pi camera and a set of filters made with low cost acrylics. This device allows imaging in scales ranging from single colonies to entire plates. We developed a set of genetic components (e.g. promoters, coding sequences, terminators) and vectors following the standard framework of Golden Gate, which allowed the fabrication of genetic constructs in a combinatorial, low cost and robust manner. In order to provide simultaneous imaging of multiple wavelength signals, we screened a series of long stokes shift fluorescent proteins that could be combined with cyan/green fluorescent proteins. We found CyOFP1, mBeRFP and sfGFP to be the most compatible set for 3-channel fluorescent imaging. We developed open source Python code to operate the hardware to run time-lapse experiments with automated control of illumination and camera and a Python module to analyze data and extract meaningful biological information. To demonstrate the potential application of this integral system, we tested its performance on a diverse range of imaging assays often used in disciplines such as microbial ecology, microbiology and synthetic biology. We also assessed its potential use in a high school environment to teach biology, hardware design, optics, and programming. Together, these results demonstrate the successful integration of open source hardware, software, genetic resources and customizable manufacturing to obtain a powerful, low cost and robust system for education, scientific research and bioengineering. All the resources developed here are available under open source licenses.

Low cost and open source multi-fluorescence imaging system for teaching and research in biology and bioengineering

PubMed Central

Herrera, Roberto; Keymer, Juan; Marzullo, Timothy; Rudge, Timothy

2017-01-01

The advent of easy-to-use open source microcontrollers, off-the-shelf electronics and customizable manufacturing technologies has facilitated the development of inexpensive scientific devices and laboratory equipment. In this study, we describe an imaging system that integrates low-cost and open-source hardware, software and genetic resources. The multi-fluorescence imaging system consists of readily available 470 nm LEDs, a Raspberry Pi camera and a set of filters made with low cost acrylics. This device allows imaging in scales ranging from single colonies to entire plates. We developed a set of genetic components (e.g. promoters, coding sequences, terminators) and vectors following the standard framework of Golden Gate, which allowed the fabrication of genetic constructs in a combinatorial, low cost and robust manner. In order to provide simultaneous imaging of multiple wavelength signals, we screened a series of long stokes shift fluorescent proteins that could be combined with cyan/green fluorescent proteins. We found CyOFP1, mBeRFP and sfGFP to be the most compatible set for 3-channel fluorescent imaging. We developed open source Python code to operate the hardware to run time-lapse experiments with automated control of illumination and camera and a Python module to analyze data and extract meaningful biological information. To demonstrate the potential application of this integral system, we tested its performance on a diverse range of imaging assays often used in disciplines such as microbial ecology, microbiology and synthetic biology. We also assessed its potential use in a high school environment to teach biology, hardware design, optics, and programming. Together, these results demonstrate the successful integration of open source hardware, software, genetic resources and customizable manufacturing to obtain a powerful, low cost and robust system for education, scientific research and bioengineering. All the resources developed here are available under open source licenses. PMID:29140977

Sources and fractionation processes influencing the isotopic distribution of H, O and C in the Long Valley hydrothermal system, California, U.S.A.

USGS Publications Warehouse

White, A.F.; Peterson, M.L.; Wollenberg, H.; Flexser, S.

1990-01-01

The isotopic ratios of H, O and C in water within the Long Valley caldera, California reflect input from sources external to the hydrothermal reservoir. A decrease in ??D in precipitation of 0.5??? km-1, from west to east across Long Valley, is caused by the introduction of less fractionated marine moisture through a low elevation embayment in the Sierra Nevada Mountain Range. Relative to seasonal fluctuations in precipitation (-158 to -35??.), ??D ranges in hot and cold surface and groundwaters are much less variable (-135 to -105??.). Only winter and spring moisture, reflecting higher precipitation rates with lighter isotopic signatures, recharge the hydrological system. The hydrothermal fluids are mixtures of isotopically heavy recharge (??D = - 115???, ??18O = - 15???) derived from the Mammoth embayment, and isotopically lighter cold water (??D = -135???, ??18O = -18???). This cold water is not representative of current local recharge. The ??13C values for dissolved carbon in hot water are significantly heavier (- 7 to - 3???) than in cold water (-18 to -10???) denoting a separate hydrothermal origin. These ??13C values overlie the range generally attributed to magmatic degassing of CO2. However, ??13C values of metamorphosed Paleozoic basement carbonates surrounding Long Valley fall in a similar range, indicating that hydrothermal decarbonization reactions are a probable source of CO2. The ??13C and ??18O values of secondary travertime and vein calcite indicate respective fractionation with CO2 and H2O at temperatures approximating current hydrothermal conditions. ?? 1990.

Adjoint analysis of the source and path sensitivities of basin-guided waves

NASA Astrophysics Data System (ADS)

Day, Steven M.; Roten, Daniel; Olsen, Kim B.

2012-05-01

Simulations of earthquake rupture on the southern San Andreas Fault (SAF) reveal large amplifications in the San Gabriel and Los Angeles Basins (SGB and LAB) apparently associated with long-range path effects. Geometrically similar excitation patterns can be recognized repeatedly in different SAF simulations (e.g. Love wave-like energy with predominant period around 4 s, channelled southwestwardly from the SGB into LAB), yet the amplitudes with which these distinctive wavefield patterns are excited change, depending upon source details (slip distribution, direction and velocity of rupture). We describe a method for rapid calculation of the sensitivity of such predicted wavefield features to perturbations of the source kinematics, using a time-reversed (adjoint) wavefield simulation. The calculations are analogous to those done in adjoint tomography, and the same time-reversed calculation also yields path-sensitivity kernels that give further insight into the excitation mechanism. For rupture on the southernmost 300 km of SAF, LAB excitation is greatest for slip concentrated between the northern Coachella Valley and the transverse ranges, propagating to the NE and with rupture velocities between 3250 and 3500 m s-1 along that fault segment; that is, within or slightly above the velocity range (between Rayleigh and S velocities) that is energetically precluded in the limit of a sharp rupture front, highlighting the potential value of imposing physical constraints (such as from spontaneous rupture models) on source parametrizations. LAB excitation is weak for rupture to the SW and for ruptures in either direction located north of the transverse transverse ranges, whereas Ventura Basin (VTB) is preferentially excited by NE ruptures situated north of the transverse ranges. Path kernels show that LAB excitation is mediated by surface waves deflected by the velocity contrast along the southern margin of the transverse ranges, having most of their energy in basement rock until they impinge on the eastern edge of SGB, through which they are then funnelled into LAB. VTB amplification is enhanced by a similar waveguide effect.

Thymol, thyme, and other plant sources: Health and potential uses.

PubMed

Salehi, Bahare; Mishra, Abhay Prakash; Shukla, Ila; Sharifi-Rad, Mehdi; Contreras, María Del Mar; Segura-Carretero, Antonio; Fathi, Hannane; Nasrabadi, Nafiseh Nasri; Kobarfard, Farzad; Sharifi-Rad, Javad

2018-05-22

Thymol is a naturally occurring phenol monoterpene derivative of cymene and isomer of carvacrol. Thymol (10-64%) is one of the major constituent of essential oils of thyme (Thymus vulgaris L., Lamiaceae), a medicinal plant with several therapeutic properties. This plant, native to Mediterranean regions, is commonly used as a culinary herb and also with a long history of use for different medicinal purposes. Nowadays, thymol and thyme present a wide range of functional possibilities in pharmacy, food, and cosmetic industry. The interest in the formulation of pharmaceuticals, nutraceuticals, and cosmeceuticals based on thymol is due to several studies that have evaluated the potential therapeutic uses of this compound for the treatment of disorders affecting the respiratory, nervous, and cardiovascular systems. Moreover, this compound also exhibits antimicrobial, antioxidant, anticarcinogenesis, anti-inflammatory, and antispasmodic activities, as well as a potential as a growth enhancer and immunomodulator. In the present review, these bioactivities have been covered because some of them can contribute to explain the ethnopharmacology of thymol and its main source, T. vulgaris. Other important aspects about thymol are discussed: its toxicity and bioavailability, metabolism, and distribution in animals and humans. Copyright © 2018 John Wiley & Sons, Ltd.

Eavesdropping to Find Mates: The Function of Male Hearing for a Cicada-Hunting Parasitoid Fly, Emblemasoma erro (Diptera: Sarcophagidae)

PubMed Central

Stucky, Brian J.

2016-01-01

Females of several species of dipteran parasitoids use long-range hearing to locate hosts for their offspring by eavesdropping on the acoustic mating calls of other insects. Males of these acoustic eavesdropping parasitoids also have physiologically functional ears, but so far, no adaptive function for male hearing has been discovered. I investigated the function of male hearing for the sarcophagid fly Emblemasoma erro Aldrich, an acoustic parasitoid of cicadas, by testing the hypothesis that both male and female E. erro use hearing to locate potential mates. I found that both male and nongravid female E. erro perform phonotaxis to the sounds of calling cicadas, that male flies engage in short-range, mate-finding behavior once they arrive at a sound source, and that encounters between females and males at a sound source can lead to copulation. Thus, cicada calling songs appear to serve as a mate-finding cue for both sexes of E. erro. Emblemasoma erro’s mate-finding behavior is compared to that of other sarcophagid flies, other acoustic parasitoids, and nonacoustic eavesdropping parasitoids. PMID:27382133

Wakefields in Coherent Synchrotron Radiation

NASA Astrophysics Data System (ADS)

Billinghurst, Brant E.; Bergstrom, J. C.; Baribeau, C.; Batten, T.; Dallin, L.; May, Tim E.; Vogt, J. M.; Wurtz, Ward A.; Warnock, Robert L.; Bizzozero, D. A.; Kramer, S.; Michaelian, K. H.

2016-06-01

When the electron bunches in a storage ring are sufficiently short the electrons act coherently producing radiation several orders of magnitude more intense than normal synchrotron radiation. This is referred to as Coherent Syncrotron Radiation (CSR). Due to the potential of CSR to provide a good source of Terahertz radiation for our users, the Canadian Light Source (CLS) has been researching the production and application of CSR. CSR has been produced at the CLS for many years, and has been used for a number of applications. However, resonances that permeate the spectrum at wavenumber intervals of 0.074 cm-1, and are highly stable under changes in the machine setup, have hampered some experiments. Analogous resonances were predicted long ago in an idealized theory. Through experiments and further calculations we elucidate the resonance and wakefield mechanisms in the CLS vacuum chamber. The wakefield is observed directly in the 30-110 GHz range by rf diodes. These results are consistent with observations made by the interferometer in the THz range. Also discussed will be some practical examples of the application of CSR for the study of condensed phase samples using both transmission and Photoacoustic techniques.

The Pearson-Readhead Survey of Compact Extragalactic Radio Sources from Space. I. The Images

NASA Astrophysics Data System (ADS)

Lister, M. L.; Tingay, S. J.; Murphy, D. W.; Piner, B. G.; Jones, D. L.; Preston, R. A.

2001-06-01

We present images from a space-VLBI survey using the facilities of the VLBI Space Observatory Programme (VSOP), drawing our sample from the well-studied Pearson-Readhead survey of extragalactic radio sources. Our survey has taken advantage of long space-VLBI baselines and large arrays of ground antennas, such as the Very Long Baseline Array and European VLBI Network, to obtain high-resolution images of 27 active galactic nuclei and to measure the core brightness temperatures of these sources more accurately than is possible from the ground. A detailed analysis of the source properties is given in accompanying papers. We have also performed an extensive series of simulations to investigate the errors in VSOP images caused by the relatively large holes in the (u,v)-plane when sources are observed near the orbit normal direction. We find that while the nominal dynamic range (defined as the ratio of map peak to off-source error) often exceeds 1000:1, the true dynamic range (map peak to on-source error) is only about 30:1 for relatively complex core-jet sources. For sources dominated by a strong point source, this value rises to approximately 100:1. We find the true dynamic range to be a relatively weak function of the difference in position angle (P.A.) between the jet P.A. and u-v coverage major axis P.A. For regions with low signal-to-noise ratios, typically located down the jet away from the core, large errors can occur, causing spurious features in VSOP images that should be interpreted with caution.

Detecting continuous gravitational waves with superfluid 4He

NASA Astrophysics Data System (ADS)

Singh, S.; De Lorenzo, L. A.; Pikovski, I.; Schwab, K. C.

2017-07-01

Direct detection of gravitational waves is opening a new window onto our universe. Here, we study the sensitivity to continuous-wave strain fields of a kg-scale optomechanical system formed by the acoustic motion of superfluid helium-4 parametrically coupled to a superconducting microwave cavity. This narrowband detection scheme can operate at very high Q-factors, while the resonant frequency is tunable through pressurization of the helium in the 0.1-1.5 kHz range. The detector can therefore be tuned to a variety of astrophysical sources and can remain sensitive to a particular source over a long period of time. For thermal noise limited sensitivity, we find that strain fields on the order of h˜ {10}-23/\\sqrt{{Hz}} are detectable. Measuring such strains is possible by implementing state of the art microwave transducer technology. We show that the proposed system can compete with interferometric detectors and potentially surpass the gravitational strain limits set by them for certain pulsar sources within a few months of integration time.

Characteristics and Source Apportionment of Marine Aerosols over East China Sea Using a Source-oriented Chemical Transport Model

NASA Astrophysics Data System (ADS)

Kang, M.; Zhang, H.; Fu, P.

2017-12-01

Marine aerosols exert a strong influence on global climate change and biogeochemical cycling, as oceans cover beyond 70% of the Earth's surface. However, investigations on marine aerosols are relatively limited at present due to the difficulty and inconvenience in sampling marine aerosols as well as their diverse sources. East China Sea (ECS), lying over the broad shelf of the western North Pacific, is adjacent to the Asian mainland, where continental-scale air pollution could impose a heavy load on the marine atmosphere through long-range atmospheric transport. Thus, contributions of major sources to marine aerosols need to be identified for policy makers to develop cost effective control strategies. In this work, a source-oriented version of the Community Multiscale Air Quality (CMAQ) model, which can directly track the contributions from multiple emission sources to marine aerosols, is used to investigate the contributions from power, industry, transportation, residential, biogenic and biomass burning to marine aerosols over the ECS in May and June 2014. The model simulations indicate significant spatial and temporal variations of concentrations as well as the source contributions. This study demonstrates that the Asian continent can greatly affect the marine atmosphere through long-range transport.

Sources of heavy metal pollution in agricultural soils of a rapidly industrializing area in the Yangtze Delta of China.

PubMed

Xu, Xianghua; Zhao, Yongcun; Zhao, Xiaoyan; Wang, Yudong; Deng, Wenjing

2014-10-01

The rapid industrialization and urbanization in developing countries have increased pollution by heavy metals, which is a concern for human health and the environment. In this study, 230 surface soil samples (0-20cm) were collected from agricultural areas of Jiaxing, a rapidly industrializing area in the Yangtze Delta of China. Sequential Gaussian simulation (SGS) and multivariate factorial kriging analysis (FKA) were used to identify and explore the sources of heavy metal pollution for eight metals (Cu, Zn, Pb, Cr, Ni, Cd, Hg and As). Localized hot-spots of pollution were identified for Cu, Zn, Pb, Cr, Ni and Cd with area percentages of 0.48 percent, 0.58 percent, 2.84 percent, 2.41 percent, 0.74 percent, and 0.68 percent, respectively. The areas with Hg pollution covered approximately 38 percent whereas no potential pollution risk was found for As. The soil parent material and point sources of pollution had significant influences on Cr, Ni, Cu, Zn and Cd levels, except for the influence of agricultural management practices also accounted for micro-scale variations (nugget effect) for Cu and Zn pollution. Short-range (4km) diffusion processes had a significant influence on Cu levels, although they did not appear to be the dominant sources of Zn and Cd variation. The short-range diffusion pollution arising from current and historic industrial emissions and urbanization, and long-range (33km) variations in soil parent materials and/or diffusion jointly determined the current concentrations of soil Pb. The sources of Hg pollution risk may be attributed to the atmosphere deposition of industrial emission and historical use of Hg-containing pesticides. Copyright © 2014 Elsevier Inc. All rights reserved.

Diversity in sound pressure levels and estimated active space of resident killer whale vocalizations.

PubMed

Miller, Patrick J O

2006-05-01

Signal source intensity and detection range, which integrates source intensity with propagation loss, background noise and receiver hearing abilities, are important characteristics of communication signals. Apparent source levels were calculated for 819 pulsed calls and 24 whistles produced by free-ranging resident killer whales by triangulating the angles-of-arrival of sounds on two beamforming arrays towed in series. Levels in the 1-20 kHz band ranged from 131 to 168 dB re 1 microPa at 1 m, with differences in the means of different sound classes (whistles: 140.2+/-4.1 dB; variable calls: 146.6+/-6.6 dB; stereotyped calls: 152.6+/-5.9 dB), and among stereotyped call types. Repertoire diversity carried through to estimates of active space, with "long-range" stereotyped calls all containing overlapping, independently-modulated high-frequency components (mean estimated active space of 10-16 km in sea state zero) and "short-range" sounds (5-9 km) included all stereotyped calls without a high-frequency component, whistles, and variable calls. Short-range sounds are reported to be more common during social and resting behaviors, while long-range stereotyped calls predominate in dispersed travel and foraging behaviors. These results suggest that variability in sound pressure levels may reflect diverse social and ecological functions of the acoustic repertoire of killer whales.

Potential-splitting approach applied to the Temkin-Poet model for electron scattering off the hydrogen atom and the helium ion

NASA Astrophysics Data System (ADS)

Yarevsky, E.; Yakovlev, S. L.; Larson, Å; Elander, N.

2015-06-01

The study of scattering processes in few body systems is a difficult problem especially if long range interactions are involved. In order to solve such problems, we develop here a potential-splitting approach for three-body systems. This approach is based on splitting the reaction potential into a finite range core part and a long range tail part. The solution to the Schrödinger equation for the long range tail Hamiltonian is found analytically, and used as an incoming wave in the three body scattering problem. This reformulation of the scattering problem makes it suitable for treatment by the exterior complex scaling technique in the sense that the problem after the complex dilation is reduced to a boundary value problem with zero boundary conditions. We illustrate the method with calculations on the electron scattering off the hydrogen atom and the positive helium ion in the frame of the Temkin-Poet model.

25 CFR 170.415 - What is pre-project planning?

Code of Federal Regulations, 2010 CFR

2010-04-01

... Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER INDIAN RESERVATION ROADS PROGRAM Planning, Design, and Construction of Indian Reservation Roads Program Facilities Long-Range... sources and identification of other funding sources to expedite the planning, design, and construction of...

Discrimination between long-range transport and local pollution sources and precise delineation of polluted soil layers using integrated geophysical-geochemical methods.

NASA Astrophysics Data System (ADS)

Magiera, Tadeusz; Szuszkiewisz, Marcin; Szuszkiewicz, Maria; Żogała, Bogdan

2017-04-01

The primary goal of this work was to distinguish between soil pollution from long-range and local transport of atmospheric pollutants using soil magnetometry in combination with geochemical analyses and precise delineation of polluted soil layers by using integrated magnetic (surface susceptibility, gradiometric measurement) and other geophysical techniques (conductivity and electrical resistivity tomography). The study area was located in the Izery region of Poland (within the "Black Triangle" region, which is the nickname for one of Europe's most polluted areas, where Germany, Poland and the Czech Republic meet). The study area was located in the Forest Glade where the historical local pollution source (glass factory) was active since and of 18th until the end of 19th century. The magnetic signal here was the combination of long-range transport of magnetic particles, local deposition and anthropogenic layers containing ashes and slags and partly comprising the subsoil of modern soil. Application of the set of different geophysical techniques enabled the precise location of these layers. The effect of the long-range pollution transport was observed on a neighboring hill (Granicznik) of which the western, northwestern and southwestern parts of the slope were exposed to the transport of atmospheric pollutants from the Czech Republic and Germany and Poland. Using soil magnetometry, it was possible to discriminate between long-range transport of atmospheric pollutants and anthropogenic pollution related to the former glasswork located in the Forest Glade. The magnetic susceptibility values (κ) as well as the number of "hot-spots" of volume magnetic susceptibility is significantly larger in the Forest Glade than on the Granicznik Hill where the κ is < 20 ×10-5 SI units. Generally, the western part of the Granicznik Hill is characterized by about two times higher k values than the southeastern part. This trend is attributed to the fact that the western part was subjected mostly to the long-range pollution originating from lignite power plants along the Polish border, while the southeastern part of the hill was shielded by crag and tail formation. Also the set of chemical elements connected with magnetic particles from long-range transport observed on the western slope an the top of Granicznik Hill (As, Cd, Hg, In, Mo, Sb, Se and U) is different than this observed on the Forest Glad connected with local pollution source (Cu, Nb, Ni, Pb, Sn and Zn).

Local chiral potentials with Δ -intermediate states and the structure of light nuclei

DOE PAGES

Piarulli, M.; Girlanda, L.; Schiavilla, R.; ...

2016-11-28

In this paper, we present fully local versions of the minimally nonlocal nucleon-nucleon potentials constructed in a previous paper [Piarulli et al., Phys. Rev. C 91, 024003 (2015)], and use them in hypersperical harmonics and quantum Monte Carlo calculations of ground and excited states ofmore » $^3$H, $^3$He, $^4$He, $^6$He, and $^6$Li nuclei. The long-range part of these local potentials includes one- and two-pion exchange contributions without and with $$\\Delta$$-isobars in the intermediate states up to order $Q^3$ ($Q$ denotes generically the low momentum scale) in the chiral expansion, while the short-range part consists of contact interactions up to order $Q^4$. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0–125 MeV or 0–200 MeV, and to the deuteron binding energy and $nn$ singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutoffs, $$R_{\\rm L}$$ and $$R_{\\rm S}$$, respectively, ranging from $$(R_{\\rm L},R_{\\rm S})=(1.2,0.8)$$ fm down to $(0.8,0.6)$ fm. Finally, the long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.« less

Local chiral potentials with Δ -intermediate states and the structure of light nuclei

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

Piarulli, M.; Girlanda, L.; Schiavilla, R.

In this paper, we present fully local versions of the minimally nonlocal nucleon-nucleon potentials constructed in a previous paper [Piarulli et al., Phys. Rev. C 91, 024003 (2015)], and use them in hypersperical harmonics and quantum Monte Carlo calculations of ground and excited states ofmore » $^3$H, $^3$He, $^4$He, $^6$He, and $^6$Li nuclei. The long-range part of these local potentials includes one- and two-pion exchange contributions without and with $$\\Delta$$-isobars in the intermediate states up to order $Q^3$ ($Q$ denotes generically the low momentum scale) in the chiral expansion, while the short-range part consists of contact interactions up to order $Q^4$. The low-energy constants multiplying these contact interactions are fitted to the 2013 Granada database in two different ranges of laboratory energies, either 0–125 MeV or 0–200 MeV, and to the deuteron binding energy and $nn$ singlet scattering length. Fits to these data are performed for three models characterized by long- and short-range cutoffs, $$R_{\\rm L}$$ and $$R_{\\rm S}$$, respectively, ranging from $$(R_{\\rm L},R_{\\rm S})=(1.2,0.8)$$ fm down to $(0.8,0.6)$ fm. Finally, the long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.« less

Analysis of the flow, thermal and geomechanical behavior of offshore hydrate deposits at the NGHP-02-09-A site during short- and long-term gas production scenarios

NASA Astrophysics Data System (ADS)

Moridis, G. J.; Reagan, M. T.; Queiruga, A. F.

2017-12-01

We analyze the gas production potential of recently discovered offshore hydrate deposits at the NGHP-02-09-A sSite in the Krishna-Godawari Basin of India, and the corresponding geomechanical system response during short- and long-term production. Using the most current data on the flow and geomechanical properties of the hydrate-bearing media and of the overburden, as well as information on the system boundaries, we investigate (a) the production rates of gas (CH4) and of water, their relative magnitudes and the reservoir thermal behavior in an effort to assess the viability of these deposits as energy sources, as well as (b) the potential subsidence and the effect of changing pressure and stress regimes on the porosity and permeability (and, consequently, on production). Additionally, we conduct a thorough sensitivity analysis in order to determine (a) the properties and conditions that control and dominate the system behavior, and (b) the range of the possible system response to production.

Differential tracking data types for accurate and efficient Mars planetary navigation

NASA Technical Reports Server (NTRS)

Edwards, C. D., Jr.; Kahn, R. D.; Folkner, W. M.; Border, J. S.

1991-01-01

Ways in which high-accuracy differential observations of two or more deep space vehicles can dramatically extend the power of earth-based tracking over conventional range and Doppler tracking are discussed. Two techniques - spacecraft-spacecraft differential very long baseline interferometry (S/C-S/C Delta(VLBI)) and same-beam interferometry (SBI) - are discussed. The tracking and navigation capabilities of conventional range, Doppler, and quasar-relative Delta(VLBI) are reviewed, and the S/C-S/C Delta (VLBI) and SBI types are introduced. For each data type, the formation of the observable is discussed, an error budget describing how physical error sources manifest themselves in the observable is presented, and potential applications of the technique for Space Exploration Initiative scenarios are examined. Requirements for spacecraft and ground systems needed to enable and optimize these types of observations are discussed.

Elastic parabolic equation solutions for oceanic T-wave generation and propagation from deep seismic sources.

PubMed

Frank, Scott D; Collis, Jon M; Odom, Robert I

2015-06-01

Oceanic T-waves are earthquake signals that originate when elastic waves interact with the fluid-elastic interface at the ocean bottom and are converted to acoustic waves in the ocean. These waves propagate long distances in the Sound Fixing and Ranging (SOFAR) channel and tend to be the largest observed arrivals from seismic events. Thus, an understanding of their generation is important for event detection, localization, and source-type discrimination. Recently benchmarked seismic self-starting fields are used to generate elastic parabolic equation solutions that demonstrate generation and propagation of oceanic T-waves in range-dependent underwater acoustic environments. Both downward sloping and abyssal ocean range-dependent environments are considered, and results demonstrate conversion of elastic waves into water-borne oceanic T-waves. Examples demonstrating long-range broadband T-wave propagation in range-dependent environments are shown. These results confirm that elastic parabolic equation solutions are valuable for characterization of the relationships between T-wave propagation and variations in range-dependent bathymetry or elastic material parameters, as well as for modeling T-wave receptions at hydrophone arrays or coastal receiving stations.

Economic and health impacts associated with a Salmonella Typhimurium drinking water outbreak-Alamosa, CO, 2008.

PubMed

Ailes, Elizabeth; Budge, Philip; Shankar, Manjunath; Collier, Sarah; Brinton, William; Cronquist, Alicia; Chen, Melissa; Thornton, Andrew; Beach, Michael J; Brunkard, Joan M

2013-01-01

In 2008, a large Salmonella outbreak caused by contamination of the municipal drinking water supply occurred in Alamosa, Colorado. The objectives of this assessment were to determine the full economic costs associated with the outbreak and the long-term health impacts on the community of Alamosa. We conducted a postal survey of City of Alamosa (2008 population: 8,746) households and businesses, and conducted in-depth interviews with local, state, and nongovernmental agencies, and City of Alamosa healthcare facilities and schools to assess the economic and long-term health impacts of the outbreak. Twenty-one percent of household survey respondents (n = 369/1,732) reported diarrheal illness during the outbreak. Of those, 29% (n = 108) reported experiencing potential long-term health consequences. Most households (n = 699/771, 91%) reported municipal water as their main drinking water source at home before the outbreak; afterwards, only 30% (n = 233) drank unfiltered municipal tap water. The outbreak's estimated total cost to residents and businesses of Alamosa using a Monte Carlo simulation model (10,000 iterations) was approximately $1.5 million dollars (range: $196,677-$6,002,879), and rose to $2.6 million dollars (range: $1,123,471-$7,792,973) with the inclusion of outbreak response costs to local, state and nongovernmental agencies and City of Alamosa healthcare facilities and schools. This investigation documents the significant economic and health impacts associated with waterborne disease outbreaks and highlights the potential for loss of trust in public water systems following such outbreaks.

Economic and Health Impacts Associated with a Salmonella Typhimurium Drinking Water Outbreak−Alamosa, CO, 2008

PubMed Central

Ailes, Elizabeth; Budge, Philip; Shankar, Manjunath; Collier, Sarah; Brinton, William; Cronquist, Alicia; Chen, Melissa; Thornton, Andrew; Beach, Michael J.; Brunkard, Joan M.

2013-01-01

In 2008, a large Salmonella outbreak caused by contamination of the municipal drinking water supply occurred in Alamosa, Colorado. The objectives of this assessment were to determine the full economic costs associated with the outbreak and the long-term health impacts on the community of Alamosa. We conducted a postal survey of City of Alamosa (2008 population: 8,746) households and businesses, and conducted in-depth interviews with local, state, and nongovernmental agencies, and City of Alamosa healthcare facilities and schools to assess the economic and long-term health impacts of the outbreak. Twenty-one percent of household survey respondents (n = 369/1,732) reported diarrheal illness during the outbreak. Of those, 29% (n = 108) reported experiencing potential long-term health consequences. Most households (n = 699/771, 91%) reported municipal water as their main drinking water source at home before the outbreak; afterwards, only 30% (n = 233) drank unfiltered municipal tap water. The outbreak’s estimated total cost to residents and businesses of Alamosa using a Monte Carlo simulation model (10,000 iterations) was approximately $1.5 million dollars (range: $196,677–$6,002,879), and rose to $2.6 million dollars (range: $1,123,471–$7,792,973) with the inclusion of outbreak response costs to local, state and nongovernmental agencies and City of Alamosa healthcare facilities and schools. This investigation documents the significant economic and health impacts associated with waterborne disease outbreaks and highlights the potential for loss of trust in public water systems following such outbreaks. PMID:23526942

Occurrences, sources and risk assessment of short- and medium-chain chlorinated paraffins in sediments from the middle reaches of the Yellow River, China.

PubMed

Qiao, Lin; Xia, Dan; Gao, Lirong; Huang, Huiting; Zheng, Minghui

2016-12-01

Chlorinated paraffins (CPs), one class of hydrophobic and toxic compounds, are easily adsorbed into sediments and then pose potential risks to the ecosystem and human health. However, few researches on short- and medium-chain CPs (SCCPs and MCCPs) in sediments have been performed. In order to comprehensively investigate the spatial distributions, sources, and ecological risks of CPs, sediments collected from the middle reaches of the Yellow River were analyzed by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS). The concentrations of SCCPs and MCCPs ranged from 11.6 to 9.76 × 10 3  ng/g dry weight (dw) and from 8.33 to 168 ng/g dw, respectively. No significant correlation was found between total organic carbon (TOC) and CP concentrations (P > 0.05). The spatial distributions showed that contamination levels of CPs were relevant to human activities. In addition, two types of sediment samples were classified by hierarchical cluster analysis (HCA) and results indicated the predominant congener groups were C 10 Cl 6-7 for SCCPs and C 14 Cl 7-8 for MCCPs. Principal component analysis (PCA) revealed that SCCPs and MCCPs in the sediments may have different sources, and SCCPs are likely to come from the production and use of CP-42 and CP-52. Moreover, complex environmental processes, including long-range transportation via the atmosphere and/or river, deposition and degradation of CPs, resulted in increased abundances of short chain and low chlorinated congeners in sediment samples compared with commercial mixtures, and different homolog patterns among samples. The significant negative correlation between SCCP concentrations and MCCP/SCCP ratios could be related to long-range transport of CPs. A preliminary risk assessment indicated that CPs at current levels posed no significant ecological risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

Population genomic analyses reveal a history of range expansion and trait evolution across the native and invaded range of yellow starthistle (Centaurea solstitialis)

PubMed Central

BARKER, BRITTANY S.; ANDONIAN, KRIKOR; SWOPE, SARAH M.; LUSTER, DOUGLAS G.; DLUGOSCH, KATRINA M.

2017-01-01

Identifying sources of genetic variation and reconstructing invasion routes for non-native introduced species is central to understanding the circumstances under which they may evolve increased invasiveness. In this study, we used genome-wide single nucleotide polymorphisms to study the colonization history of Centaurea solstitialis in its native range in Eurasia and invasions into the Americas. We leveraged this information to pinpoint key evolutionary shifts in plant size, a focal trait associated with invasiveness in this species. Our analyses revealed clear population genomic structure of potential source populations in Eurasia, including deep differentiation of a lineage found in the southern Apennine and Balkan Peninsulas and divergence among populations in Asia, eastern Europe, and western Europe. We found strongest support for an evolutionary scenario in which western European populations were derived from an ancient admixture event between populations from eastern Europe and Asia, and subsequently served as the main genetic ‘bridgehead’ for introductions to the Americas. Introductions to California appear to be from a single source region, and multiple, independent introductions of divergent genotypes likely occurred into the Pacific Northwest. Plant size has evolved significantly at three points during range expansion, including a large size increase in the lineage responsible for the aggressive invasion of California’s interior. These results reveal a long history of colonization, admixture, and trait evolution in C. solstitialis, and suggest routes for improving evidence-based management decisions for one of the most ecologically and economically damaging invasive species in the western United States. PMID:28029713

Prediction of plant lncRNA by ensemble machine learning classifiers.

PubMed

Simopoulos, Caitlin M A; Weretilnyk, Elizabeth A; Golding, G Brian

2018-05-02

In plants, long non-protein coding RNAs are believed to have essential roles in development and stress responses. However, relative to advances on discerning biological roles for long non-protein coding RNAs in animal systems, this RNA class in plants is largely understudied. With comparatively few validated plant long non-coding RNAs, research on this potentially critical class of RNA is hindered by a lack of appropriate prediction tools and databases. Supervised learning models trained on data sets of mostly non-validated, non-coding transcripts have been previously used to identify this enigmatic RNA class with applications largely focused on animal systems. Our approach uses a training set comprised only of empirically validated long non-protein coding RNAs from plant, animal, and viral sources to predict and rank candidate long non-protein coding gene products for future functional validation. Individual stochastic gradient boosting and random forest classifiers trained on only empirically validated long non-protein coding RNAs were constructed. In order to use the strengths of multiple classifiers, we combined multiple models into a single stacking meta-learner. This ensemble approach benefits from the diversity of several learners to effectively identify putative plant long non-coding RNAs from transcript sequence features. When the predicted genes identified by the ensemble classifier were compared to those listed in GreeNC, an established plant long non-coding RNA database, overlap for predicted genes from Arabidopsis thaliana, Oryza sativa and Eutrema salsugineum ranged from 51 to 83% with the highest agreement in Eutrema salsugineum. Most of the highest ranking predictions from Arabidopsis thaliana were annotated as potential natural antisense genes, pseudogenes, transposable elements, or simply computationally predicted hypothetical protein. Due to the nature of this tool, the model can be updated as new long non-protein coding transcripts are identified and functionally verified. This ensemble classifier is an accurate tool that can be used to rank long non-protein coding RNA predictions for use in conjunction with gene expression studies. Selection of plant transcripts with a high potential for regulatory roles as long non-protein coding RNAs will advance research in the elucidation of long non-protein coding RNA function.

Two-dimensional melting of colloids with long-range attractive interactions.

PubMed

Du, Di; Doxastakis, Manolis; Hilou, Elaa; Biswal, Sibani Lisa

2017-02-22

The solid-liquid melting transition in a two-dimensional (2-D) attractive colloidal system is visualized using superparamagnetic colloids that interact through a long-range isotropic attractive interaction potential, which is induced using a high-frequency rotating magnetic field. Various experiments, supported by Monte Carlo simulations, are carried out over a range of interaction potentials and densities to determine structure factors, Lindermann parameters, and translational and orientational order parameters. The system shows a first-order solid-liquid melting transition. Simulations and experiments suggest that dislocations and disclinations simultaneously unbind during melting. This is in direct contrast with reports of 2-D melting of paramagnetic particles that interact with a repulsive interaction potential.

Long-term trends in dissolved iron and DOC concentration linked to nitrate depletion in riparian soils

NASA Astrophysics Data System (ADS)

Musolff, Andreas; Selle, Benny; Fleckenstein, Jan H.; Oosterwoud, Marieke R.; Tittel, Jörg

2016-04-01

The instream concentrations of dissolved organic carbon (DOC) are rising in many catchments of the northern hemisphere. Elevated concentrations of DOC, mainly in the form of colored humic components, increase efforts and costs of drinking water purification. In this study, we evaluated a long-term dataset of 110 catchments draining into German drinking water reservoirs in order to assess sources of DOC and drivers of a potential long-term change. The average DOC concentrations across the wide range of different catchments were found to be well explained by the catchment's topographic wetness index. Higher wetness indices were connected to higher average DOC concentrations, which implies that catchments with shallow topography and pronounced riparian wetlands mobilize more DOC. Overall, 37% of the investigated catchments showed a significant long-term increase in DOC concentrations, while 22% exhibited significant negative trends. Moreover, we found that increasing trends in DOC were positively correlated to trends in dissolved iron concentrations at pH≤6 due to remobilization of DOC previously sorbed to iron minerals. Both, increasing trends in DOC and dissolve iron were found to be connected to decreasing trends and low concentrations of nitrate (below ~6 mg/L). This was especially observed in forested catchments where atmospheric N-depositions were the major source for nitrate availability. In these catchments, we also found long-term increases of phosphate concentrations. Therefore, we argue that dissolved iron, DOC and phosphate were jointly released under iron-reducing conditions when nitrate as a competing electron acceptor was too low in concentrations to prevent the microbial iron reduction. In contrast, we could not explain the observed increasing trends in DOC, iron and phosphate concentrations by the long-term trends of pH, sulfate or precipitation. Altogether this study gives strong evidence that both, source and long-term increases in DOC are primarily controlled by riparian wetland soils within the catchments. Here, the achievement of a long-term reduction in nitrogen deposition may in turn lead to a more pronounced iron reduction and a subsequent release of DOC and other iron-bound substances such as phosphate.

Comparison of source apportionment of PM2.5 using receptor models in the main hub port city of East Asia: Busan

NASA Astrophysics Data System (ADS)

Jeong, Ju-Hee; Shon, Zang-Ho; Kang, Minsung; Song, Sang-Keun; Kim, Yoo-Keun; Park, Jinsoo; Kim, Hyunjae

2017-01-01

The contributions of various PM2.5 emission sources to ambient PM2.5 levels during 2013 in the main hub port city (Busan, South Korea) of East Asia was quantified using several receptor modeling techniques. Three receptor models of principal component analysis/absolute principal component score (PCA/APCS), positive matrix factorization (PMF), and chemical mass balance (CMB) were used to apportion the source of PM2.5 obtained from the target city. The results of the receptor models indicated that the secondary formation of PM2.5 was the dominant (45-60%) contributor to PM2.5 levels in the port city of Busan. The PMF and PCA/APCS suggested that ship emission was a non-negligible contributor of PM2.5 (up to about 10%) in the study area, whereas it was a negligible contributor based on CMB. The magnitude of source contribution estimates to PM2.5 levels differed significantly among these three models due to their limitations (e.g., PM2.5 emission source profiles and restrictions of the models). Potential source contribution function and concentration-weighted trajectory analyses indicated that long-range transport from sources in the eastern China and Yellow Sea contributed significantly to the level of PM2.5 in Busan.

Modelling the Contribution of Long-range Transport of Ammonium Nitrates to Urban Air Pollution and Human Exposure in the United Kingdom

NASA Astrophysics Data System (ADS)

Reis, S.; Vieno, M.; Beck, R.; Ots, R.; Moring, A.; Steinle, S.; Heal, M. R.; Doherty, R. M.

2014-12-01

Urban air pollution and its effects on human health remain to be a challenge in spite of substantial reductions in the emissions of air pollutants (e.g. sulphur dioxide, nitrogen oxides) over the past decades in Europe. While primary pollutants play a vital role in urban air pollution, recent model studies highlight and quantify the relevance of long-range transport of secondary pollution (e.g. secondary inorganic aerosols such as ammonium sulphates and nitrates, or ground level ozone) for the exceedance of local air quality limit values in urban areas across Europe. This contribution can be seen in recurring episodes, for instance in spring 2014, with very high levels of fine particulate matter (PM2.5) in Paris, London and other European cities, as well as in elevated background levels throughout the year. While we will focus on the contribution to exceedances of PM2.5 limit values here, this transboundary transport has wider implications for the deposition of reactive nitrogen far from the source as well. As local authorities are tasked with ensuring the attainment of air quality limit values, exceedances caused by long-range transport, with emissions originating from sources outside of their jurisdiction present substantial challenges. Furthermore, while policy measures have successfully addressed emissions from large point sources in the past, and made progress towards reducing pollution from road vehicles, emissions of ammonia from agricultural sources - a key component for the long-range transport of secondary inorganic aerosols - have remained relatively stable in Europe. Using the example of Europe and the UK, we demonstrate in our presentation how atmospheric chemistry transport modelling across different scales (from regional to local) can provide vital insight in the mechanisms of and relative contributions to the formation of secondary inorganic aerosols. In addition, we illustrate how this modelling capability can inform the design of efficient control strategies by quantifying the effect of different policy measures targeted at specific source sectors, and highlight the role of transboundary air pollution to local air pollution challenges.

A new empirical potential energy function for Ar2

NASA Astrophysics Data System (ADS)

Myatt, Philip T.; Dham, Ashok K.; Chandrasekhar, Pragna; McCourt, Frederick R. W.; Le Roy, Robert J.

2018-06-01

A critical re-analysis of all available spectroscopic and virial coefficient data for Ar2 has been used to determine an improved empirical analytic potential energy function that has been 'tuned' to optimise its agreement with viscosity, diffusion and thermal diffusion data, and whose short-range behaviour is in reasonably good agreement with the most recent ab initio calculations for this system. The recommended Morse/long-range potential function is smooth and differentiable at all distances, and incorporates both the correct theoretically predicted long-range behaviour and the correct limiting short-range functional behaviour. The resulting value of the well depth is ? cm-1 and the associated equilibrium distance is re = 3.766 (±0.002) Å, while the 40Ar s-wave scattering length is -714 Å.

Effects of local emission sources on the acidification of rainwater in an industrial city in Taiwan

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

Chung-Shin Yuan; Der-Yuan Wu

1996-12-31

This study investigated the acidification of precipitation in an industrial city in Taiwan Island. The purposes of this study is two fold. The first is to characterize the status of add precipitation around the industrial city. Rainwater samples were collected by automatic rainwater samplers-located at five sampling sites which covered the entire city. The second is to investigate the potential sources of acidic species in the acid rainwater. Further study was taken to ascertain the effects of local emissions as well as long range transportation on the acidification of precipitation. Investigation of acid rain on the Island of Taiwan hasmore » been conducted since 1984. Most of these researches were short-term and/or large-scale investigations. Long-term sampling of acid rain at heavy polluted region has never been investigated yet. In this investigation, Kaohsiung was selected as the city for the intensive acid rain sampling since it is the largest industrial city as well as the largest harbor in Taiwan Island. Both dry and wet acid samples were collected daily by the automatic rainwater samplers. Major cations (H{sup +}, NH{sub 4}{sup +}, K{sup +}, Ca{sup +2}, and Mg{sup +2}), anions (F{sup -}, Cl{sup -}, NO3{sup -}, and SO4{sup -2}), and conductivity of acid samples were measured simultaneously. Actually, both pH value and conductivity were measured on site. During the period of investigation, 325 collected rainwater samples demonstrated an average pH value of 5.2 with the range of 3.1 to 6.3. This investigation revealed that emissions from local sources such as power plants, petrochemical plants, and cement plants play important roles on the acidification of rainwater in the industrial city in Taiwan.« less

Long range intermolecular interactions between the alkali diatomics Na2, K2, and NaK

NASA Astrophysics Data System (ADS)

Zemke, Warren T.; Byrd, Jason N.; Michels, H. Harvey; Montgomery, John A.; Stwalley, William C.

2010-06-01

Long range interactions between the ground state alkali diatomics Na2-Na2, K2-K2, Na2-K2, and NaK-NaK are examined. Interaction energies are first determined from ab initio calculations at the coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] level of theory, including counterpoise corrections. Long range energies calculated from diatomic molecular properties (polarizabilities and dipole and quadrupole moments) are then compared with the ab initio energies. A simple asymptotic model potential ELR=Eelec+Edisp+Eind is shown to accurately represent the intermolecular interactions for these systems at long range.

Long range intermolecular interactions between the alkali diatomics Na(2), K(2), and NaK.

PubMed

Zemke, Warren T; Byrd, Jason N; Michels, H Harvey; Montgomery, John A; Stwalley, William C

2010-06-28

Long range interactions between the ground state alkali diatomics Na(2)-Na(2), K(2)-K(2), Na(2)-K(2), and NaK-NaK are examined. Interaction energies are first determined from ab initio calculations at the coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] level of theory, including counterpoise corrections. Long range energies calculated from diatomic molecular properties (polarizabilities and dipole and quadrupole moments) are then compared with the ab initio energies. A simple asymptotic model potential E(LR)=E(elec)+E(disp)+E(ind) is shown to accurately represent the intermolecular interactions for these systems at long range.

Quantifying the contribution of long-range transport to particulate matter (PM) mass loadings at a suburban site in the north-western Indo-Gangetic Plain (NW-IGP)

NASA Astrophysics Data System (ADS)

Pawar, H.; Garg, S.; Kumar, V.; Sachan, H.; Arya, R.; Sarkar, C.; Chandra, B. P.; Sinha, B.

2015-08-01

Many sites in the densely populated Indo-Gangetic Plain (IGP) frequently exceed the national ambient air quality standard (NAAQS) of 100 μg m-3 for 24 h average PM10 and 60 μg m-3 for 24 h average PM2.5 mass loadings, exposing residents to hazardous levels of particulate matter (PM) throughout the year. We quantify the contribution of long-range transport to elevated PM levels and the number of exceedance events through a back-trajectory climatology analysis of air masses arriving at the IISER Mohali Atmospheric Chemistry facility (30.667° N, 76.729° E; 310 m a.m.s.l.) for the period August 2011-June 2013. Air masses arriving at the receptor site were classified into six clusters, which represent synoptic-scale air-mass transport patterns. Long-range transport from the west leads to significant enhancements in the average fine- and coarse-mode PM mass loadings during all seasons. The contribution of long-range transport from the west and south-west (source regions: Arabia, Thar Desert, Middle East and Afghanistan) to coarse-mode PM varied between 9 and 57 % of the total PM10-2.5 mass. Local pollution episodes (wind speed < 1 m s-1) contributed to enhanced PM2.5 mass loadings during both the winter and summer seasons and to enhanced coarse-mode PM only during the winter season. South-easterly air masses (source region: eastern IGP) were associated with significantly lower fine- and coarse-mode PM mass loadings during all seasons. The fraction of days in each season during which the PM mass loadings exceeded the national ambient air quality standard was controlled by long-range transport to a much lesser degree. For the local cluster, which represents regional air masses (source region: NW-IGP), the fraction of days during which the national ambient air quality standard (NAAQS) of 60 μg m-3 for 24 h average PM2.5 was exceeded varied between 36 % of the days associated with this synoptic-scale transport during the monsoon, and 95 % during post-monsoon and winter seasons; the fraction of days during which the NAAQS of 100 μg m-3 for the 24 h average PM10 was exceeded, varied between 48 % during the monsoon and 98 % during the post-monsoon season. Long-range transport was responsible for both, bringing air masses with a significantly lower fraction of exceedance days from the eastern IGP and air masses with a moderate increase in the fraction of exceedance days from the west (source regions: Arabia, Thar Desert, Middle East and Afghanistan). In order to bring PM mass loadings into compliance with the NAAQS and to reduce the number of exceedance days, mitigation of regional combustion sources in the NW-IGP needs to be given highest priority.

Temporal trends and bioavailability assessment of heavy metals in the sediments of Deception Bay, Queensland, Australia.

PubMed

Brady, James P; Ayoko, Godwin A; Martens, Wayde N; Goonetilleke, Ashantha

2014-12-15

Thirteen sites in Deception Bay, Queensland, Australia were sampled three times over a period of 7 months and assessed for contamination by a range of heavy metals, primarily As, Cd, Cr, Cu, Pb and Hg. Fraction analysis, enrichment factors and Principal Components Analysis-Absolute Principal Component Scores (PCA-APCS) analysis were conducted in order to identify the potential bioavailability of these elements of concern and their sources. Hg and Te were identified as the elements of highest enrichment in Deception Bay while marine sediments, shipping and antifouling agents were identified as the sources of the Weak Acid Extractable Metals (WE-M), with antifouling agents showing long residence time for mercury contamination. This has significant implications for the future of monitoring and regulation of heavy metal contamination within Deception Bay. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sources and geographical origins of fine aerosols in Paris (France)

NASA Astrophysics Data System (ADS)

Bressi, M.; Sciare, J.; Ghersi, V.; Mihalopoulos, N.; Petit, J.-E.; Nicolas, J. B.; Moukhtar, S.; Rosso, A.; Féron, A.; Bonnaire, N.; Poulakis, E.; Theodosi, C.

2013-12-01

The present study aims at identifying and apportioning the major sources of fine aerosols in Paris (France) - the second largest megacity in Europe -, and determining their geographical origins. It is based on the daily chemical composition of PM2.5 characterised during one year at an urban background site of Paris (Bressi et al., 2013). Positive Matrix Factorization (EPA PMF3.0) was used to identify and apportion the sources of fine aerosols; bootstrapping was performed to determine the adequate number of PMF factors, and statistics (root mean square error, coefficient of determination, etc.) were examined to better model PM2.5 mass and chemical components. Potential Source Contribution Function (PSCF) and Conditional Probability Function (CPF) allowed the geographical origins of the sources to be assessed; special attention was paid to implement suitable weighting functions. Seven factors named ammonium sulfate (A.S.) rich factor, ammonium nitrate (A.N.) rich factor, heavy oil combustion, road traffic, biomass burning, marine aerosols and metals industry were identified; a detailed discussion of their chemical characteristics is reported. They respectively contribute 27, 24, 17, 14, 12, 6 and 1% of PM2.5 mass (14.7 μg m-3) on the annual average; their seasonal variability is discussed. The A.S. and A.N. rich factors have undergone north-eastward mid- or long-range transport from Continental Europe, heavy oil combustion mainly stems from northern France and the English Channel, whereas road traffic and biomass burning are primarily locally emitted. Therefore, on average more than half of PM2.5 mass measured in the city of Paris is due to mid- or long-range transport of secondary aerosols stemming from continental Europe, whereas local sources only contribute a quarter of the annual averaged mass. These results imply that fine aerosols abatement policies conducted at the local scale may not be sufficient to notably reduce PM2.5 levels at urban background sites in Paris, suggesting instead more coordinated strategies amongst neighbouring countries. Similar conclusions might be drawn in other continental urban background sites given the transboundary nature of PM2.5 pollution.

Sources and geographical origins of fine aerosols in Paris (France)

NASA Astrophysics Data System (ADS)

Bressi, M.; Sciare, J.; Ghersi, V.; Mihalopoulos, N.; Petit, J.-E.; Nicolas, J. B.; Moukhtar, S.; Rosso, A.; Féron, A.; Bonnaire, N.; Poulakis, E.; Theodosi, C.

2014-08-01

The present study aims at identifying and apportioning fine aerosols to their major sources in Paris (France) - the second most populated "larger urban zone" in Europe - and determining their geographical origins. It is based on the daily chemical composition of PM2.5 examined over 1 year at an urban background site of Paris (Bressi et al., 2013). Positive matrix factorization (EPA PMF3.0) was used to identify and apportion fine aerosols to their sources; bootstrapping was performed to determine the adequate number of PMF factors, and statistics (root mean square error, coefficient of determination, etc.) were examined to better model PM2.5 mass and chemical components. Potential source contribution function (PSCF) and conditional probability function (CPF) allowed the geographical origins of the sources to be assessed; special attention was paid to implement suitable weighting functions. Seven factors, namely ammonium sulfate (A.S.)-rich factor, ammonium nitrate (A.N.)-rich factor, heavy oil combustion, road traffic, biomass burning, marine aerosols and metal industry, were identified; a detailed discussion of their chemical characteristics is reported. They contribute 27, 24, 17, 14, 12, 6 and 1% of PM2.5 mass (14.7 μg m-3) respectively on the annual average; their seasonal variability is discussed. The A.S.- and A.N.-rich factors have undergone mid- or long-range transport from continental Europe; heavy oil combustion mainly stems from northern France and the English Channel, whereas road traffic and biomass burning are primarily locally emitted. Therefore, on average more than half of PM2.5 mass measured in the city of Paris is due to mid- or long-range transport of secondary aerosols stemming from continental Europe, whereas local sources only contribute a quarter of the annual averaged mass. These results imply that fine-aerosol abatement policies conducted at the local scale may not be sufficient to notably reduce PM2.5 levels at urban background sites in Paris, suggesting instead more coordinated strategies amongst neighbouring countries. Similar conclusions might be drawn in other continental urban background sites given the transboundary nature of PM2.5 pollution.

Spatial multi-scale variability of soil nutrients in relation to environmental factors in a typical agricultural region, eastern China.

PubMed

Liu, Yang; Lv, Jianshu; Zhang, Bing; Bi, Jun

2013-04-15

Identifying the sources of spatial variability and deficiency risk of soil nutrients is a crucial issue for soil and agriculture management. A total of 1247 topsoil samples (0-20 cm) were collected at the nodes of a 2×2 km grid in Rizhao City and the contents of soil organic carbon (OC), total nitrogen (TN), and total phosphorus (TP) were determined. Factorial kriging analysis (FKA), stepwise multiple regression, and indicator kriging (IK) were appled to investigate the scale dependent correlations among soil nutrients, identify the sources of spatial variability at each spatial scale, and delineate the potential risk of soil nutrient deficiency. Linear model of co-regionalization (LMC) fitting indicated that the presence of multi-scale variation was comprised of nugget effect, an exponential structure with a range of 12 km (local scale), and a spherical structure with a range of 84 km (regional scale). The short-range variation of OC and TN was mainly dominated by land use types, and TP was controlled by terrain. At long-range scale, spatial variation of OC, TN, and TP was dominated by parent material. Indicator kriging maps depicted the probability of soil nutrient deficiency compared with the background values in eastern Shandong province. The high deficiency risk area of all nutrient integration was mainly located in eastern and northwestern parts. Copyright © 2013 Elsevier B.V. All rights reserved.

Contributed review: quantum cascade laser based photoacoustic detection of explosives.

PubMed

Li, J S; Yu, B; Fischer, H; Chen, W; Yalin, A P

2015-03-01

Detecting trace explosives and explosive-related compounds has recently become a topic of utmost importance for increasing public security around the world. A wide variety of detection methods and an even wider range of physical chemistry issues are involved in this very challenging area. Optical sensing methods, in particular mid-infrared spectrometry techniques, have a great potential to become a more desirable tools for the detection of explosives. The small size, simplicity, high output power, long-term reliability make external cavity quantum cascade lasers (EC-QCLs) the promising spectroscopic sources for developing analytical instrumentation. This work reviews the current technical progress in EC-QCL-based photoacoustic spectroscopy for explosives detection. The potential for both close-contact and standoff configurations using this technique is completely presented over the course of approximately the last one decade.

Contributed Review: Quantum cascade laser based photoacoustic detection of explosives

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

Li, J. S., E-mail: jingsong-li@ahu.edu.cn; Yu, B.; Fischer, H.

2015-03-15

Detecting trace explosives and explosive-related compounds has recently become a topic of utmost importance for increasing public security around the world. A wide variety of detection methods and an even wider range of physical chemistry issues are involved in this very challenging area. Optical sensing methods, in particular mid-infrared spectrometry techniques, have a great potential to become a more desirable tools for the detection of explosives. The small size, simplicity, high output power, long-term reliability make external cavity quantum cascade lasers (EC-QCLs) the promising spectroscopic sources for developing analytical instrumentation. This work reviews the current technical progress in EC-QCL-based photoacousticmore » spectroscopy for explosives detection. The potential for both close-contact and standoff configurations using this technique is completely presented over the course of approximately the last one decade.« less

What Are the Main Drivers of the Bitcoin Price? Evidence from Wavelet Coherence Analysis

PubMed Central

Kristoufek, Ladislav

2015-01-01

The Bitcoin has emerged as a fascinating phenomenon in the Financial markets. Without any central authority issuing the currency, the Bitcoin has been associated with controversy ever since its popularity, accompanied by increased public interest, reached high levels. Here, we contribute to the discussion by examining the potential drivers of Bitcoin prices, ranging from fundamental sources to speculative and technical ones, and we further study the potential influence of the Chinese market. The evolution of relationships is examined in both time and frequency domains utilizing the continuous wavelets framework, so that we not only comment on the development of the interconnections in time but also distinguish between short-term and long-term connections. We find that the Bitcoin forms a unique asset possessing properties of both a standard financial asset and a speculative one. PMID:25874694

What are the main drivers of the Bitcoin price? Evidence from wavelet coherence analysis.

PubMed

Kristoufek, Ladislav

2015-01-01

The Bitcoin has emerged as a fascinating phenomenon in the Financial markets. Without any central authority issuing the currency, the Bitcoin has been associated with controversy ever since its popularity, accompanied by increased public interest, reached high levels. Here, we contribute to the discussion by examining the potential drivers of Bitcoin prices, ranging from fundamental sources to speculative and technical ones, and we further study the potential influence of the Chinese market. The evolution of relationships is examined in both time and frequency domains utilizing the continuous wavelets framework, so that we not only comment on the development of the interconnections in time but also distinguish between short-term and long-term connections. We find that the Bitcoin forms a unique asset possessing properties of both a standard financial asset and a speculative one.

Investigating the origin of vagrant dusky groupers, Epinephelus marginatus (Lowe, 1834), in coastal waters of Réunion Island.

PubMed

Reid, Kerry; Crochelet, Estelle; Bloomer, Paulette; Hoareau, Thierry B

2016-10-01

Due to their geographic isolation, biotas of oceanic islands are likely influenced by episodic long distance dispersal events, but such observations are scarce. In June 2012, fishermen from Réunion Island caught an unknown specimen of grouper, identified as dusky grouper Epinephelus marginatus (Lowe, 1834). This was highly unexpected considering the large distance of its closest verified occurrence (South Africa, ∼2500km). To identify the origin of this specimen and the mechanisms driving this potential long distance colonization, we combined genetic analyses and hydrodynamic connectivity modeling approaches. Molecular markers and samples from various locations across the distribution range resulted in the identification of three putative source populations. The Réunion specimen clustered genetically with South Africa. The estimated spawning period in relation to the connectivity modeling of larvae showed no possible direct connection between South Africa and Réunion. However, connectivity was predicted through intermediate stepping stone populations likely located around the southern tip of Madagascar, where the occurrence of the species has yet to be verified. The results further highlight the potential role of the cyclone Bingiza (February 2011) in the connection between Madagascar and Réunion. This shows that cyclones may be an important driver in long distance colonization of oceanic islands. Copyright © 2016 Elsevier Inc. All rights reserved.

Modeling aerosol suspension from soils and oceans as sources of micropollutants to air.

PubMed

Qureshi, Asif; MacLeod, Matthew; Hungerbühler, Konrad

2009-10-01

Soil and marine aerosol suspension are two physical mass transfer processes that are not usually included in models describing fate and transport of environmental pollutants. Here, we review the literature on soil and marine aerosol suspension and estimate aerosol suspension mass transfer velocities for inclusion in multimedia models, as a global average and on a 1 x 1 scale. The yearly, global average mass transfer velocity for soil aerosol suspension is estimated to be 6 x 10(-10)mh(-1), approximately an order of magnitude smaller than marine aerosol suspension, which is estimated to be 8 x 10(-9)mh(-1). Monthly averages of these velocities can be as high as 10(-7)mh(-1) and 10(-5)mh(-1) for soil and marine aerosol suspension, respectively, depending on location. We use a unit-world multimedia model to analyze the relevance of these two suspension processes as a mechanism that enhances long-range atmospheric transport of pollutants. This is done by monitoring a metric of long-range transport potential, phi-one thousand (phi1000), that denotes the fraction of modeled emissions to air, water or soil in a source region that reaches a distance of 1000 km in air. We find that when the yearly, globally averaged mass transfer velocity is used, marine aerosol suspension increases phi1000 only fractionally for both emissions to air and water. However, enrichment of substances in marine aerosols, or speciation between ionic and neutral forms in ocean water may increase the influence of this surface-to-air transfer process. Soil aerosol suspension can be the dominant process for soil-to-air transfer in an emission-to-soil scenario for certain substances that have a high affinity to soil. When a suspension mass transfer velocity near the maximum limit is used, soil suspension remains important if the emissions are made to soil, and marine aerosol suspension becomes important regardless of if emissions are made to air or water compartments. We recommend that multimedia models designed to assess the environmental fate and long-range transport behavior of substances with a range of chemical properties include both aerosol suspension processes, using the mass transfer velocities estimated here.

Refined potentials for rare gas atom adsorption on rare gas and alkali-halide surfaces

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Heinbockel, J. H.; Outlaw, R. A.

1985-01-01

The utilization of models of interatomic potential for physical interaction to estimate the long range attractive potential for rare gases and ions is discussed. The long range attractive force is calculated in terms of the atomic dispersion properties. A data base of atomic dispersion parameters for rare gas atoms, alkali ion, and halogen ions is applied to the study of the repulsive core; the procedure for evaluating the repulsive core of ion interactions is described. The interaction of rare gas atoms on ideal rare gas solid and alkali-halide surfaces is analyzed; zero coverage absorption potentials are derived.

Comparison of three methods reducing the beam parameter product of a laser diode stack for long range laser illumination applications

NASA Astrophysics Data System (ADS)

Lutz, Yves; Poyet, Jean-Michel; Metzger, Nicolas

2013-10-01

Laser diode stacks are interesting laser sources for active imaging illuminators. They allow the accumulation of large amounts of energy in multi-pulse mode, which is well suited for long-range image recording. Even when laser diode stacks are equipped with fast-axis collimation (FAC) and slow-axis collimation (SAC) microlenses, their beam parameter product (BPP) are not compatible with a direct use in highly efficient and compact illuminators. This is particularly true when narrow divergences are required such as for long range applications. To overcome these difficulties, we conducted investigations in three different ways. A first near infrared illuminator based on the use of conductively cooled mini-bars was designed, realized and successfully tested during outdoor experimentations. This custom specified stack was then replaced in a second step by an off-the-shelf FAC + SAC micro lensed stack where the brightness was increased by polarization overlapping. The third method still based on a commercial laser diode stack uses a non imaging optical shaping principle resulting in a virtually restacked laser source with enhanced beam parameters. This low cost, efficient and low alignment sensitivity beam shaping method allows obtaining a compact and high performance laser diode illuminator for long range active imaging applications. The three methods are presented and compared in this paper.

Interferometric system based on swept source-optical coherence tomography scheme applied to the measurement of distances of industrial interest

NASA Astrophysics Data System (ADS)

Morel, Eneas N.; Russo, Nélida A.; Torga, Jorge R.; Duchowicz, Ricardo

2016-01-01

We used an interferometric technique based on typical optical coherence tomography (OCT) schemes for measuring distances of industrial interest. The system employed as a light source a tunable erbium-doped fiber laser of ˜20-pm bandwidth with a tuning range between 1520 and 1570 nm. It has a sufficiently long coherence length to enable long depth range imaging. A set of fiber Bragg gratings was used as a self-calibration method, which has the advantage of being a passive system that requires no additional electronic devices. The proposed configuration and the coherence length of the laser enlarge the range of maximum distances that can be measured with the common OCT configuration, maintaining a good axial resolution. A measuring range slightly >17 cm was determined. The system performance was evaluated by studying the repeatability and axial resolution of the results when the same optical path difference was measured. Additionally, the thickness of a semitransparent medium was also measured.

The long-term problems of contaminated land: Sources, impacts and countermeasures

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

Baes, C.F. III

1986-11-01

This report examines the various sources of radiological land contamination; its extent; its impacts on man, agriculture, and the environment; countermeasures for mitigating exposures; radiological standards; alternatives for achieving land decontamination and cleanup; and possible alternatives for utilizing the land. The major potential sources of extensive long-term land contamination with radionuclides, in order of decreasing extent, are nuclear war, detonation of a single nuclear weapon (e.g., a terrorist act), serious reactor accidents, and nonfission nuclear weapons accidents that disperse the nuclear fuels (termed ''broken arrows'').

Universality and tails of long-range interactions in one dimension

NASA Astrophysics Data System (ADS)

Valiente, Manuel; Öhberg, Patrik

2017-07-01

Long-range interactions and, in particular, two-body potentials with power-law long-distance tails are ubiquitous in nature. For two bosons or fermions in one spatial dimension, the latter case being formally equivalent to three-dimensional s -wave scattering, we show how generic asymptotic interaction tails can be accounted for in the long-distance limit of scattering wave functions. This is made possible by introducing a generalization of the collisional phase shifts to include space dependence. We show that this distance dependence is universal, in that it does not depend on short-distance details of the interaction. The energy dependence is also universal, and is fully determined by the asymptotic tails of the two-body potential. As an important application of our findings, we describe how to eliminate finite-size effects with long-range potentials in the calculation of scattering phase shifts from exact diagonalization. We show that even with moderately small system sizes it is possible to accurately extract phase shifts that would otherwise be plagued with finite-size errors. We also consider multichannel scattering, focusing on the estimation of open channel asymptotic interaction strengths via finite-size analysis.

Irrigated Acreage Within the Basin and Range Carbonate-Rock Aquifer System, White Pine County, Nevada, and Adjacent Areas in Nevada and Utah

USGS Publications Warehouse

Welborn, Toby L.; Moreo, Michael T.

2007-01-01

Accurate delineations of irrigated acreage are needed for the development of water-use estimates and in determining water-budget calculations for the Basin and Range carbonate-rock aquifer system (BARCAS) study. Irrigated acreage is estimated routinely for only a few basins in the study area. Satellite imagery from the Landsat Thematic Mapper and Enhanced Thematic Mapper platforms were used to delineate irrigated acreage on a field-by-field basis for the entire study area. Six hundred and forty-three fields were delineated. The water source, irrigation system, crop type, and field activity for 2005 were identified and verified through field reconnaissance. These data were integrated in a geodatabase and analyzed to develop estimates of irrigated acreage for the 2000, 2002, and 2005 growing seasons by hydrographic area and subbasin. Estimated average annual potential evapotranspiration and average annual precipitation also were estimated for each field.The geodatabase was analyzed to determine the spatial distribution of field locations, the total amount of irrigated acreage by potential irrigation water source, by irrigation system, and by crop type. Irrigated acreage in 2005 totaled nearly 32,000 acres ranging from less than 200 acres in Butte, Cave, Jakes, Long, and Tippett Valleys to 9,300 acres in Snake Valley. Irrigated acreage increased about 20 percent between 2000 and 2005 and increased the most in Snake and White River Valleys. Ground-water supplies as much as 80 percent of irrigation water during dry years. Almost 90 percent of the irrigated acreage was planted with alfalfa.

Characteristics of Fine Particulate Carbonaceous Aerosol at Two Remote Sites in Central Asia

EPA Science Inventory

Central Asia is a relatively understudied region of the world in terms of characterizing ambient particulate matter (PM) and quantifying source impacts of PM at receptor locations, although it is speculated to have an important role as a source region for long-range transport of ...

Implications of evolutionary engineering for growth and recombinant protein production in methanol-based growth media in the yeast Pichia pastoris.

PubMed

Moser, Josef W; Prielhofer, Roland; Gerner, Samuel M; Graf, Alexandra B; Wilson, Iain B H; Mattanovich, Diethard; Dragosits, Martin

2017-03-17

Pichia pastoris is a widely used eukaryotic expression host for recombinant protein production. Adaptive laboratory evolution (ALE) has been applied in a wide range of studies in order to improve strains for biotechnological purposes. In this context, the impact of long-term carbon source adaptation in P. pastoris has not been addressed so far. Thus, we performed a pilot experiment in order to analyze the applicability and potential benefits of ALE towards improved growth and recombinant protein production in P. pastoris. Adaptation towards growth on methanol was performed in replicate cultures in rich and minimal growth medium for 250 generations. Increased growth rates on these growth media were observed at the population and single clone level. Evolved populations showed various degrees of growth advantages and trade-offs in non-evolutionary growth conditions. Genome resequencing revealed a wide variety of potential genetic targets associated with improved growth performance on methanol-based growth media. Alcohol oxidase represented a mutational hotspot since four out of seven evolved P. pastoris clones harbored mutations in this gene, resulting in decreased Aox activity, despite increased growth rates. Selected clones displayed strain-dependent variations for AOX-promoter based recombinant protein expression yield. One particularly interesting clone showed increased product titers ranging from a 2.5-fold increase in shake flask batch culture to a 1.8-fold increase during fed batch cultivation. Our data indicate a complex correlation of carbon source, growth context and recombinant protein production. While similar experiments have already shown their potential in other biotechnological areas where microbes were evolutionary engineered for improved stress resistance and growth, the current dataset encourages the analysis of the potential of ALE for improved protein production in P. pastoris on a broader scale.

Hazard assessment of long-period ground motions for the Nankai Trough earthquakes

NASA Astrophysics Data System (ADS)

Maeda, T.; Morikawa, N.; Aoi, S.; Fujiwara, H.

2013-12-01

We evaluate a seismic hazard for long-period ground motions associated with the Nankai Trough earthquakes (M8~9) in southwest Japan. Large interplate earthquakes occurring around the Nankai Trough have caused serious damages due to strong ground motions and tsunami; most recent events were in 1944 and 1946. Such large interplate earthquake potentially causes damages to high-rise and large-scale structures due to long-period ground motions (e.g., 1985 Michoacan earthquake in Mexico, 2003 Tokachi-oki earthquake in Japan). The long-period ground motions are amplified particularly on basins. Because major cities along the Nankai Trough have developed on alluvial plains, it is therefore important to evaluate long-period ground motions as well as strong motions and tsunami for the anticipated Nankai Trough earthquakes. The long-period ground motions are evaluated by the finite difference method (FDM) using 'characterized source models' and the 3-D underground structure model. The 'characterized source model' refers to a source model including the source parameters necessary for reproducing the strong ground motions. The parameters are determined based on a 'recipe' for predicting strong ground motion (Earthquake Research Committee (ERC), 2009). We construct various source models (~100 scenarios) giving the various case of source parameters such as source region, asperity configuration, and hypocenter location. Each source region is determined by 'the long-term evaluation of earthquakes in the Nankai Trough' published by ERC. The asperity configuration and hypocenter location control the rupture directivity effects. These parameters are important because our preliminary simulations are strongly affected by the rupture directivity. We apply the system called GMS (Ground Motion Simulator) for simulating the seismic wave propagation based on 3-D FDM scheme using discontinuous grids (Aoi and Fujiwara, 1999) to our study. The grid spacing for the shallow region is 200 m and 100 m in horizontal and vertical, respectively. The grid spacing for the deep region is three times coarser. The total number of grid points is about three billion. The 3-D underground structure model used in the FD simulation is the Japan integrated velocity structure model (ERC, 2012). Our simulation is valid for period more than two seconds due to the lowest S-wave velocity and grid spacing. However, because the characterized source model may not sufficiently support short period components, we should be interpreted the reliable period of this simulation with caution. Therefore, we consider the period more than five seconds instead of two seconds for further analysis. We evaluate the long-period ground motions using the velocity response spectra for the period range between five and 20 second. The preliminary simulation shows a large variation of response spectra at a site. This large variation implies that the ground motion is very sensitive to different scenarios. And it requires studying the large variation to understand the seismic hazard. Our further study will obtain the hazard curves for the Nankai Trough earthquake (M 8~9) by applying the probabilistic seismic hazard analysis to the simulation results.

Aerosol transport from Chiang Mai, Thailand to Mt. Lulin, Taiwan - Implication of aerosol aging during long-range transport

NASA Astrophysics Data System (ADS)

Chuang, Ming-Tung; Lee, Chung-Te; Chou, Charles C.-K.; Engling, Guenter; Chang, Shih-Yu; Chang, Shuenn-Chin; Sheu, Guey-Rong; Lin, Neng-Huei; Sopajaree, Khajornsak; Chang, You-Jia; Hong, Guo-Jun

2016-07-01

The transport of biomass burning (BB) aerosol from Indochina may cause a potential effect on climate change in Southeast Asia, East Asia, and the Western Pacific. Up to now, the understanding of BB aerosol composition modification during long-range transport (LRT) is still very limited due to the lack of observational data. In this study, atmospheric aerosols were collected at the Suthep/Doi Ang Khang (DAK) mountain sites in Chiang Mai, Thailand and the Lulin Atmospheric Background Station (Mt. Lulin) in central Taiwan from March to April 2010 and from February to April 2013, respectively. During the study period, an upwind and downwind relationship between the Suthep/DAK and Lulin sites (2400 km apart) was validated by backward trajectories. Comprehensive aerosol properties were resolved for PM2.5 water-soluble inorganic ions, carbonaceous content, water-soluble/insoluble organic carbon (WSOC/WIOC), dicarboxylic acids and their salts (DCAS), and anhydrosugars. A Modification Factor (MF) is proposed by employing non-sea-salt potassium ion (nss-K+) or fractionalized elemental carbon evolved at 580 °C after pyrolized OC correction (EC1-OP) as a BB aerosol tracer to evaluate the mass fraction changes of aerosol components from source to receptor regions during LRT. The MF values of nss-SO42-, NH4+, NO3-, OC1 (fractionalized organic carbon evolved from room temperature to 140 °C), OP (pyrolized OC fraction), DCAS, and WSOC were above unity, which indicated that these aerosol components were enhanced during LRT as compared with those in the near-source region. In contrast, the MF values of anhydrosugars ranged from 0.1 to 0.3, indicating anhydrosugars have degraded during LRT.

Are changing emission patterns across the Northern Hemisphere influencing long-range transport contributions to background air pollution?

NASA Astrophysics Data System (ADS)

Mathur, R.; Kang, D.; Napelenok, S. L.; Xing, J.; Hogrefe, C.

2017-12-01

Air pollution reduction strategies for a region are complicated not only by the interplay of local emissions sources and several complex physical, chemical, dynamical processes in the atmosphere, but also hemispheric background levels of pollutants. Contrasting changes in emission patterns across the globe (e.g. declining emissions in North America and Western Europe in response to implementation of control measures and increasing emissions across Asia due to economic and population growth) are resulting in heterogeneous changes in the tropospheric chemical composition and are likely altering long-range transport impacts and consequently background pollution levels at receptor regions. To quantify these impacts, the WRF-CMAQ model is expanded to hemispheric scales and multi-decadal model simulations are performed for the period spanning 1990-2010 to examine changes in hemispheric air pollution resulting from changes in emissions over this period. Simulated trends in ozone and precursor species concentrations across the U.S. and the Northern Hemisphere over the past two decades are compared with those inferred from available measurements during this period. Additionally, the decoupled direct method (DDM) in CMAQ, a first- and higher-order sensitivity calculation technique, is used to estimate the sensitivity of O3 to emissions from different source regions across the Northern Hemisphere. The seasonal variations in source region contributions to background O3 are then estimated from these sensitivity calculations and will be discussed. These source region sensitivities estimated from DDM are then combined with the multi-decadal simulations of O3 distributions and emissions trends to characterize the changing contributions of different source regions to background O3 levels across North America. This characterization of changing long-range transport contributions is critical for the design and implementation of tighter national air quality standards

Measurement of Gaseous Oxidized Mercury at a SEARCH Network Site in Florida, USA

NASA Astrophysics Data System (ADS)

Huang, J.; Miller, M. B.; Gustin, M. S.

2013-12-01

There are three operationally defined forms of mercury (Hg) that have been measured in the atmosphere. These include gaseous elemental Hg (GEM), gaseous oxidized Hg (GOM), and particle-bound Hg (PBM). The chemical compounds that make up GOM are currently not well understood, and because of this we do not understand its transport and fate. Additionally, there are limitations associated with the current measurement method, the Tekran 2537/1130/1135 system. Recent work has shown that this system underestimates GOM concentrations, and may not measure all forms. Here we describe work building on ongoing research that focuses on understanding the limitations associated with the instrument, and the chemical forms of GOM. Mercury data have been collected at a Southeastern Aerosol Research and Characterization (SEARCH) network site, Outlying Landing Field (OLF), by the University of Nevada-Reno since 2006. This site is located near the Gulf of Mexico in western Florida. This site is potentially influenced by multiple Hg sources including marine air, electricity generating facilities, mobile sources, and long range transport from high elevation and inland regions. Recent work using data from this location and two others in Florida indicated that on top of background deposition, Hg input to OLF is due to local mobile sources, and long range transport in the spring. Air masses with different chemistry have been hypothesized to carry different GOM compounds. To test this hypothesis, an active Hg sampling system that collects GOM on nylon and cation-exchange membranes is being deployed at OLF. Measurements started March 2013. Here we will present data collected so far, and compare concentrations measured to those obtained using a Tekran system. Ancillary data including meteorology, criteria air pollutants, and those collected using surrogated surfaces for dry Hg deposition and Hg passive samplers will be applied to help understand the sources of GOM. Back trajectory analyses will also applied. This new method shows that different forms of GOM are present at OLF.

Frequent long-distance plant colonization in the changing Arctic.

PubMed

Alsos, Inger Greve; Eidesen, Pernille Bronken; Ehrich, Dorothee; Skrede, Inger; Westergaard, Kristine; Jacobsen, Gro Hilde; Landvik, Jon Y; Taberlet, Pierre; Brochmann, Christian

2007-06-15

The ability of species to track their ecological niche after climate change is a major source of uncertainty in predicting their future distribution. By analyzing DNA fingerprinting (amplified fragment-length polymorphism) of nine plant species, we show that long-distance colonization of a remote arctic archipelago, Svalbard, has occurred repeatedly and from several source regions. Propagules are likely carried by wind and drifting sea ice. The genetic effect of restricted colonization was strongly correlated with the temperature requirements of the species, indicating that establishment limits distribution more than dispersal. Thus, it may be appropriate to assume unlimited dispersal when predicting long-term range shifts in the Arctic.

IN-SITU THERMAL TREATMENT SYSTEM PERFORMANCE AND MASS REMOVAL METRICS AT FORT LEWIS

EPA Science Inventory

The EGDY is the source of a potentially expanding three mile long TCE plume in a sole source drinking water aquifer. Thermal remediation is being employed to reduce source mass loading to the dissolved phase aquifer plume and reduce the time to reach site cleanup goals. This is...

LESSONS LEARNED FROM IN-SITU RESISTIVE HEATING OF TCE AT FORT LEWIS, WASHINGTON

EPA Science Inventory

The EGDY is the source of a potentially expanding, three mile long TCE plume in a sole source drinking water aquifer. Thermal remediation is being employed to reduce source mass loading to the dissolved phase aquifer plume and reduce the time to reach site cleanup goals. This i...

2.3. Global-scale atmospheric dispersion of microorganisms

USGS Publications Warehouse

Griffin, Dale W.; Gonzalez-Martin, Cristina; Hoose, C.; Smith, D.J.; Delort, Anne-Marie; Amato, Pierre

2018-01-01

This chapter addresses long-range dispersion and the survival of microorganisms across a wide range of altitudes in Earth's atmosphere. Topics include mechanisms of dispersion, survivability of microorganisms known to be associated with long-range transport, natural and artificial sources of bioaerosols, residence time estimation through the use of proxy aerosols, transport and emission models, and monitoring assays (both culture and molecular based). We conclude with a discussion of the known limits for Earth's biosphere boundary, relating aerobiology studies to planetary exploration given the large degree of overlapping requirements for in situ studies (including low biomass life detection and contamination control).

Sources and composition of PM2.5 in the Colorado Front Range during the DISCOVER-AQ study

NASA Astrophysics Data System (ADS)

Valerino, M. J.; Johnson, J. J.; Izumi, J.; Orozco, D.; Hoff, R. M.; Delgado, R.; Hennigan, C. J.

2017-01-01

Measurements of particulate matter (PM2.5) chemical composition were carried out in Golden, CO, during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field study. Chemical composition was dominated by organic compounds, which comprised an average of 75% of the PM2.5 mass throughout the study. Most of the organic matter was secondary (i.e., secondary organic aerosol) and appears to derive predominantly from regional sources, rather than the Denver metropolitan area. The concentration and composition of PM2.5 in Golden were strongly influenced by highly regular wind patterns and the site's close proximity to the mountains ( 5 km). This second factor may be the cause of distinct differences between observations in Golden and those in downtown Denver, despite a distance between the sites of only 15 km. Concentrations of aerosol nitrate, ammonium, and elemental carbon increased significantly during the daytime when the winds were from the northeast, indicating a strong local source for these compounds. Local sources of dust appeared to minimally impact the Golden site, although this was not likely representative of other conditions in the Colorado Front Range. Conversely, dust that had undergone long-range transport from the southwestern U.S. likely impacted the entire Colorado Front Range, including Golden. During this event, water-soluble Ca2+ concentrations exceeded 1 µg m-3, and the PM2.5/PM10 ratio reached its lowest level throughout the study. The long-range transport of wildfire emissions also impacted the Colorado Front Range for 1-2 days during DISCOVER-AQ. The smoke event was characterized by high concentrations of organics and water-soluble K+. The results show a complex array of sources, and atmospheric processes influence summertime PM in the Colorado Front Range.

Urban air quality in a mid-size city - PM2.5 composition, sources and identification of impact areas: From local to long range contributions

NASA Astrophysics Data System (ADS)

Squizzato, Stefania; Cazzaro, Marta; Innocente, Elena; Visin, Flavia; Hopke, Philip K.; Rampazzo, Giancarlo

2017-04-01

Urban air quality represents a major public health burden and is a long-standing concern to European citizens. Combustion processes and traffic-related emissions represent the main primary particulate matter (PM) sources in urban areas. Other sources can also affect air quality (e.g., secondary aerosol, industrial) depending on the characteristics of the study area. Thus, the identification and the apportionment of all sources is of crucial importance to make effective corrective decisions within environmental policies. The aim of this study is to evaluate the impacts of different emissions sources on PM2.5 concentrations and compositions in a mid-size city in the Po Valley (Treviso, Italy). Data have been analyzed to highlight compositional differences (elements and major inorganic ions), to determine PM2.5 sources and their contributions, and to evaluate the influence of air mass movements. Non-parametric tests, positive matrix factorization (PMF), conditional bivariate probability function (CBPF), and concentration weighted trajectory (CWT) have been used in a multi-chemometrics approach to understand the areal-scale (proximate, local, long-range) where different sources act on PM2.5 levels and composition. Results identified three levels of scale from which the pollution arose: (i) a proximate local scale (close to the sampling site) for traffic non-exhaust and resuspended dust sources; (ii) a local urban scale (including both sampling site and areas close to them) for combustion and industrial; and (iii) a regional scale characterized by ammonium nitrate and ammonium sulfate. This approach and results can help to develop and adopt better air quality policy action.

Simulation study of a high power density rectenna array for biomedical implantable devices

NASA Astrophysics Data System (ADS)

Day, John; Yoon, Hargsoon; Kim, Jaehwan; Choi, Sang H.; Song, Kyo D.

2016-04-01

The integration of wireless power transmission devices using microwaves into the biomedical field is close to a practical reality. Implanted biomedical devices need a long lasting power source or continuous power supply. Recent development of high efficiency rectenna technology enables continuous power supply to these implanted devices. Due to the size limit of most of medical devices, it is imperative to minimize the rectenna as well. The research reported in this paper reviews the effects of close packing the rectenna elements which show the potential of directly empowering the implanted devices, especially within a confined area. The rectenna array is tested in the X band frequency range.

Vagrant western red-shouldered hawks: origins, natal dispersal patterns, and survival

USGS Publications Warehouse

Bloom, Peter H.; Scott, J. Michael; Papp, Joseph M.; Thomas, Scott E.; Kidd, Jeff W.

2011-01-01

We report the results of a 40-year study of the western Red-shouldered Hawk (Buteo lineatus elegans) involving the banding of 2742 nestlings in southern California from 1970 to 2009 (this study) plus 127 nestlings banded in other California studies (1956–2008) and the analyses of 119 records of subsequent recovery from the Bird Banding Laboratory (1957–2009). Of the Red-shouldered Hawks recovered, 109 (91.6%) moved 100 km (long-distance dispersers). Three (2.5%), all long-distance dispersers, were vagrants (recovered outside the species' range of residency), and were found 374 to 843 km northeast and south of their banding locations in the Mojave, Great Basin, and Vizcaino deserts. The distribution of directions of short-distance dispersal was bipolar, closely corresponding with the northwest—southeast orientation of the species' range in southern California, while that of long-distance dispersers was mainly to the north. One of 10 long-distance dispersers, a nonvagrant, survived well into the age of breeding (103.0 months), whereas eight of the other nine perished before 14.5 months. The implications of vagrancy for conservation of this resident subspecies are that a relatively small source area can contribute genetic material over a vastly larger receiving area but rarely does so because of high mortality rates. Nonetheless, the movements of vagrants we documented provide evidence for the species' potential to populate new landscapes in response to changing environmental conditions and to maintain genetic heterogeneity within existing populations.

Modelling phytoremediation by the hyperaccumulating fern, Pteris vittata, of soils historically contaminated with arsenic.

PubMed

Shelmerdine, Paula A; Black, Colin R; McGrath, Steve P; Young, Scott D

2009-05-01

Pteris vittata plants were grown on twenty-one UK soils contaminated with arsenic (As) from a wide range of natural and anthropogenic sources. Arsenic concentration was measured in fern fronds, soil and soil pore water collected with Rhizon samplers. Isotopically exchangeable soil arsenate was determined by equilibration with (73)As(V). Removal of As from the 21 soils by three sequential crops of P. vittata ranged between 0.1 and 13% of total soil As. Ferns grown on a soil subjected to long-term sewage sludge application showed reduced uptake of As because of high available phosphate concentrations. A combined solubility-uptake model was parameterised to enable prediction of phytoremediation success from estimates of soil As, 'As-lability' and soil pH. The model was used to demonstrate the remediation potential of P. vittata under different soil conditions and with contrasting assumptions regarding re-supply of the labile As pool from unavailable forms.

Observations in eastern England of elevated methyl iodide concentrations in air of atlantic origin

NASA Astrophysics Data System (ADS)

Oram, D. E.; Penkett, S. A.

Atmospheric methyl iodide (CH 3I) has been measured at a ground-based site in eastern England for two consecutive summers. Maximum values of 43.1 pptv and 28.9 pptv were recorded in 1989 and 1990, respectively. CH 3I was not detectable in the autumn and winter months. Episodes of elevated concentration persisted for periods ranging from a few hours to several days. The origin of much of the observed CH 31 would appear to be the Atlantic Ocean, indicating the presence of large source areas, possibly phytoplankton blooms, in ocean waters. If so, this work provides the first evidence of long-range transport of an important iodine-bearing species at concentrations of hemispheric significance. Estimates are made of the dry deposition velocity of CH 3I and the potential impact of elevated tropospheric levels on the human uptake of iodine.

The Relationship between Host Lifespan and Pathogen Reservoir Potential: An Analysis in the System Arabidopsis thaliana-Cucumber mosaic virus

PubMed Central

Hily, Jean Michel; García, Adrián; Moreno, Arancha; Plaza, María; Wilkinson, Mark D.; Fereres, Alberto; Fraile, Aurora; García-Arenal, Fernando

2014-01-01

Identification of the determinants of pathogen reservoir potential is central to understand disease emergence. It has been proposed that host lifespan is one such determinant: short-lived hosts will invest less in costly defenses against pathogens, so that they will be more susceptible to infection, more competent as sources of infection and/or will sustain larger vector populations, thus being effective reservoirs for the infection of long-lived hosts. This hypothesis is sustained by analyses of different hosts of multihost pathogens, but not of different genotypes of the same host species. Here we examined this hypothesis by comparing two genotypes of the plant Arabidopsis thaliana that differ largely both in life-span and in tolerance to its natural pathogen Cucumber mosaic virus (CMV). Experiments with the aphid vector Myzus persicae showed that both genotypes were similarly competent as sources for virus transmission, but the short-lived genotype was more susceptible to infection and was able to sustain larger vector populations. To explore how differences in defense against CMV and its vector relate to reservoir potential, we developed a model that was run for a set of experimentally-determined parameters, and for a realistic range of host plant and vector population densities. Model simulations showed that the less efficient defenses of the short-lived genotype resulted in higher reservoir potential, which in heterogeneous host populations may be balanced by the longer infectious period of the long-lived genotype. This balance was modulated by the demography of both host and vector populations, and by the genetic composition of the host population. Thus, within-species genetic diversity for lifespan and defenses against pathogens will result in polymorphisms for pathogen reservoir potential, which will condition within-population infection dynamics. These results are relevant for a better understanding of host-pathogen co-evolution, and of the dynamics of pathogen emergence. PMID:25375140

Long-range correlation of the membrane potential in neocortical neurons during slow oscillation

PubMed Central

Volgushev, Maxim; Chauvette, Sylvain; Timofeev, Igor

2012-01-01

Large amplitude slow waves are characteristic for the summary brain activity, recorded as electroencephalogram (EEG) or local field potentials (LFP), during deep stages of sleep and some types of anesthesia. Slow rhythm of the synchronized EEG reflects an alternation of active (depolarized, UP) and silent (hyperpolarized, DOWN) states of neocortical neurons. In neurons, involvement in the generalized slow oscillation results in a long-range synchronization of changes of their membrane potential as well as their firing. Here, we aimed at intracellular analysis of details of this synchronization. We asked which components of neuronal activity exhibit long-range correlations during the synchronized EEG? To answer this question, we made simultaneous intracellular recordings from two to four neocortical neurons in cat neocortex. We studied how correlated is the occurrence of active and silent states, and how correlated are fluctuations of the membrane potential in pairs of neurons located close one to the other or separated by up to 13 mm. We show that strong long-range correlation of the membrane potential was observed only (i) during the slow oscillation but not during periods without the oscillation, (ii) during periods which included transitions between the states but not during within-the-state periods, and (iii) for the low-frequency (<5 Hz) components of membrane potential fluctuations but not for the higher-frequency components (>10 Hz). In contrast to the neurons located several millimeters one from the other, membrane potential fluctuations in neighboring neurons remain strongly correlated during periods without slow oscillation. We conclude that membrane potential correlation in distant neurons is brought about by synchronous transitions between the states, while activity within the states is largely uncorrelated. The lack of the generalized fine-scale synchronization of membrane potential changes in neurons during the active states of slow oscillation may allow individual neurons to selectively engage in short living episodes of correlated activity—a process that may be similar to dynamical formation of neuronal ensembles during activated brain states. PMID:21854963

Long range Debye-Hückel correction for computation of grid-based electrostatic forces between biomacromolecules

PubMed Central

2014-01-01

Background Brownian dynamics (BD) simulations can be used to study very large molecular systems, such as models of the intracellular environment, using atomic-detail structures. Such simulations require strategies to contain the computational costs, especially for the computation of interaction forces and energies. A common approach is to compute interaction forces between macromolecules by precomputing their interaction potentials on three-dimensional discretized grids. For long-range interactions, such as electrostatics, grid-based methods are subject to finite size errors. We describe here the implementation of a Debye-Hückel correction to the grid-based electrostatic potential used in the SDA BD simulation software that was applied to simulate solutions of bovine serum albumin and of hen egg white lysozyme. Results We found that the inclusion of the long-range electrostatic correction increased the accuracy of both the protein-protein interaction profiles and the protein diffusion coefficients at low ionic strength. Conclusions An advantage of this method is the low additional computational cost required to treat long-range electrostatic interactions in large biomacromolecular systems. Moreover, the implementation described here for BD simulations of protein solutions can also be applied in implicit solvent molecular dynamics simulations that make use of gridded interaction potentials. PMID:25045516

Identifying the source of fluvial terrace deposits using XRF scanning and Canonical Discriminant Analysis: A case study of the Chihshang terraces, eastern Taiwan

NASA Astrophysics Data System (ADS)

Chang, Queenie; Lee, Jian-Cheng; Hunag, Jyh-Jaan; Wei, Kuo-Yen; Chen, Yue-Gau; Byrne, Timothy B.

2018-05-01

The source of fluvial deposits in terraces provides important information about the catchment fluvial processes and landform evolution. In this study, we propose a novel approach that combines high-resolution Itrax-XRF scanning and Canonical Discriminant Analysis (CDA) to identify the source of fine-grained fluvial terrace deposits. We apply this approach to a group of terraces that are located on the hanging wall of the Chihshang Fault in eastern Taiwan with two possible sources, the Coastal Range on the east and the Central Range on the west. Our results of standard samples from the two potential sources show distinct ranges of canonical variables, which provided a better separation ability than individual chemical elements. We then tested the possibility of using this approach by applying it to several samples with known sediment sources and obtain positive results. Applying this same approach to the fine-grained sediments in Chihshang terraces indicates that they are mostly composed of Coastal Range material but also contain some inputs from the Central Range. In two lowest terraces T1 and T2, the fine-grained deposits show significant Central Range component. For terrace T4, the results show less Central Range input and a trend of decreasing Central Range influences up section. The Coastal Range material becomes dominant in the two highest terraces T7 and T10. Sediments in terrace T5 appear to have been potentially altered by post-deposition chemical alteration processes and are not included in the analysis. Our results show that the change in source material in the terraces deposits was relatively gradual rather than the sharp changes suggested by the composition of the gravels and conglomerates. We suggest that this change in sources is related to the change in dominant fluvial processes that controlled by the tectonic activity.

Supercontinuum white light lasers for flow cytometry

PubMed Central

Telford, William G.; Subach, Fedor V.; Verkhusha, Vladislav V.

2009-01-01

Excitation of fluorescent probes for flow cytometry has traditionally been limited to a few discrete laser lines, an inherent limitation in our ability to excite the vast array of fluorescent probes available for cellular analysis. In this report, we have used a supercontinuum (SC) white light laser as an excitation source for flow cytometry. By selectively filtering the wavelength of interest, almost any laser wavelength in the visible spectrum can be separated and used for flow cytometric analysis. The white light lasers used in this study were integrated into a commercial flow cytometry platform, and a series of high-transmission bandpass filters used to select wavelength ranges from the blue (~480 nm) to the long red (>700 nm). Cells labeled with a variety of fluorescent probes or expressing fluorescent proteins were then analyzed, in comparison with traditional lasers emitting at wavelengths similar to the filtered SC source. Based on a standard sensitivity metric, the white light laser bandwidths produced similar excitation levels to traditional lasers for a wide variety of fluorescent probes and expressible proteins. Sensitivity assessment using fluorescent bead arrays confirmed that the SC laser and traditional sources resulted in similar levels of detection sensitivity. Supercontinuum white light laser sources therefore have the potential to remove a significant barrier in flow cytometric analysis, namely the limitation of excitation wavelengths. Almost any visible wavelength range can be made available for excitation, allowing access to virtually any fluorescent probe, and permitting “fine-tuning” of excitation wavelength to particular probes. PMID:19072836

Tunable, continuous-wave, ultraviolet source based on intracavity sum-frequency-generation in an optical parametric oscillator using BiB₃O₆.

PubMed

Devi, Kavita; Kumar, S Chaitanya; Ebrahim-Zadeh, M

2013-10-21

We report a continuous-wave (cw) source of tunable radiation across 333-345 nm in the ultraviolet (UV) using bismuth triborate, BiB₃O₆ (BIBO) as the nonlinear gain material. The source is based on internal sum-frequency-generation (SFG) in a cw singly-resonant optical parametric oscillator (OPO) pumped at 532 nm. The compact tunable source employs a 30-mm-long MgO:sPPLT crystal as the OPO gain medium and a 5-mm-long BIBO crystal for intracavity SFG of the signal and pump, providing up to 21.6 mW of UV power at 339.7 nm, with >15 mW over 64% of the SFG tuning range. The cw OPO is also tunable across 1158-1312 nm in the idler, delivering as much as 1.7 W at 1247 nm, with >1W over 65% of the tuning range. The UV output at maximum power exhibits passive power stability better than 3.4% rms and frequency stability of 193 GHz over more than one minute.

Stability and cytotoxicity of crystallin amyloid nanofibrils

NASA Astrophysics Data System (ADS)

Kaur, Manmeet; Healy, Jackie; Vasudevamurthy, Madhusudan; Lassé, Moritz; Puskar, Ljiljana; Tobin, Mark J.; Valery, Celine; Gerrard, Juliet A.; Sasso, Luigi

2014-10-01

Previous work has identified crystallin proteins extracted from fish eye lenses as a cheap and readily available source for the self-assembly of amyloid nanofibrils. However, before exploring potential applications, the biophysical aspects and safety of this bionanomaterial need to be assessed so as to ensure that it can be effectively and safely used. In this study, crude crystallin amyloid fibrils are shown to be stable across a wide pH range, in a number of industrially relevant solvents, at both low and high temperatures, and in the presence of proteases. Crystallin nanofibrils were compared to well characterised insulin and whey protein fibrils using Thioflavin T assays and TEM imaging. Cell cytotoxicity assays suggest no adverse impact of both mature and fragmented crystallin fibrils on cell viability of Hec-1a endometrial cells. An IR microspectroscopy study supports long-term structural integrity of crystallin nanofibrils.Previous work has identified crystallin proteins extracted from fish eye lenses as a cheap and readily available source for the self-assembly of amyloid nanofibrils. However, before exploring potential applications, the biophysical aspects and safety of this bionanomaterial need to be assessed so as to ensure that it can be effectively and safely used. In this study, crude crystallin amyloid fibrils are shown to be stable across a wide pH range, in a number of industrially relevant solvents, at both low and high temperatures, and in the presence of proteases. Crystallin nanofibrils were compared to well characterised insulin and whey protein fibrils using Thioflavin T assays and TEM imaging. Cell cytotoxicity assays suggest no adverse impact of both mature and fragmented crystallin fibrils on cell viability of Hec-1a endometrial cells. An IR microspectroscopy study supports long-term structural integrity of crystallin nanofibrils. Electronic supplementary information (ESI) available: ThT fluorescence graphs of buffers and solvents used for normalising ThT fluorescence of PNFs in the experiments (Fig. S1 and S2). Representative TEM images of fibrils over a wide range of pH and at variety of temperatures (Fig. S3 and S4). IR spectra of the amide fingerprinting region, including baseline (Fig. S5). See DOI: 10.1039/c4nr04624b

Ultra-broadband phase-sensitive optical time-domain reflectometry with a temporally sequenced multi-frequency source.

PubMed

Wang, Zhaoyong; Pan, Zhengqing; Fang, Zujie; Ye, Qing; Lu, Bin; Cai, Haiwen; Qu, Ronghui

2015-11-15

A phase-sensitive optical time-domain reflectometry (Φ-OTDR) with a temporally sequenced multi-frequency (TSMF) source is proposed. This technique can improve the system detection bandwidth without the sensing range decreasing. Up to 0.5 MHz detection bandwidth over 9.6 km is experimentally demonstrated as an example. To the best of our knowledge, this is the first time that such a high detection bandwidth over such a long sensing range is reported in Φ-OTDR-based distributed vibration sensing. The technical issues of TSMF Φ-OTDR are discussed in this Letter. This technique will help Φ-OTDR find new important foreground in long-haul distributed broadband-detection applications, such as structural-health monitoring and partial-discharge online monitoring of high voltage power cables.

Discovery of long-distance gamete dispersal in a lichen-forming ascomycete.

PubMed

Ronnås, Cecilia; Werth, Silke; Ovaskainen, Otso; Várkonyi, Gergely; Scheidegger, Christoph; Snäll, Tord

2017-10-01

Accurate estimates of gamete and offspring dispersal range are required for the understanding and prediction of spatial population dynamics and species persistence. Little is known about gamete dispersal in fungi, especially in lichen-forming ascomycetes. Here, we estimate the dispersal functions of clonal propagules, gametes and ascospores of the epiphytic lichen Lobaria pulmonaria. We use hierarchical Bayesian parentage analysis, which integrates genetic and ecological information from multiannual colonization and dispersal source data collected in a large, old-growth forest landscape. The effective dispersal range of gametes is several hundred metres to kilometres from potential paternal individuals. By contrast, clonal propagules disperse only tens of metres, and ascospores disperse over several thousand metres. Our study reveals the dispersal distances of individual reproductive units; clonal propagules, gametes and ascospores, which is of great importance for a thorough understanding of the spatial dynamics of ascomycetes. Sexual reproduction occurs between distant individuals. However, whereas gametes and ascospores disperse over long distances, the overall rate of colonization of trees is low. Hence, establishment is the limiting factor for the colonization of new host trees by the lichen in old-growth landscapes. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Probing Long-Range Neutrino-Mediated Forces with Atomic and Nuclear Spectroscopy.

PubMed

Stadnik, Yevgeny V

2018-06-01

The exchange of a pair of low-mass neutrinos between electrons, protons, and neutrons produces a "long-range" 1/r^{5} potential, which can be sought for in phenomena originating on the atomic and subatomic length scales. We calculate the effects of neutrino-pair exchange on transition and binding energies in atoms and nuclei. In the case of atomic s-wave states, there is a large enhancement of the induced energy shifts due to the lack of a centrifugal barrier and the highly singular nature of the neutrino-mediated potential. We derive limits on neutrino-mediated forces from measurements of the deuteron binding energy and transition energies in positronium, muonium, hydrogen, and deuterium, as well as isotope-shift measurements in calcium ions. Our limits improve on existing constraints on neutrino-mediated forces from experiments that search for new macroscopic forces by 18 orders of magnitude. Future spectroscopy experiments have the potential to probe long-range forces mediated by the exchange of pairs of standard-model neutrinos and other weakly charged particles.

Probing Long-Range Neutrino-Mediated Forces with Atomic and Nuclear Spectroscopy

NASA Astrophysics Data System (ADS)

Stadnik, Yevgeny V.

2018-06-01

The exchange of a pair of low-mass neutrinos between electrons, protons, and neutrons produces a "long-range" 1 /r5 potential, which can be sought for in phenomena originating on the atomic and subatomic length scales. We calculate the effects of neutrino-pair exchange on transition and binding energies in atoms and nuclei. In the case of atomic s -wave states, there is a large enhancement of the induced energy shifts due to the lack of a centrifugal barrier and the highly singular nature of the neutrino-mediated potential. We derive limits on neutrino-mediated forces from measurements of the deuteron binding energy and transition energies in positronium, muonium, hydrogen, and deuterium, as well as isotope-shift measurements in calcium ions. Our limits improve on existing constraints on neutrino-mediated forces from experiments that search for new macroscopic forces by 18 orders of magnitude. Future spectroscopy experiments have the potential to probe long-range forces mediated by the exchange of pairs of standard-model neutrinos and other weakly charged particles.

Eavesdropping to Find Mates: The Function of Male Hearing for a Cicada-Hunting Parasitoid Fly, Emblemasoma erro (Diptera: Sarcophagidae).

PubMed

Stucky, Brian J

2016-01-01

Females of several species of dipteran parasitoids use long-range hearing to locate hosts for their offspring by eavesdropping on the acoustic mating calls of other insects. Males of these acoustic eavesdropping parasitoids also have physiologically functional ears, but so far, no adaptive function for male hearing has been discovered. I investigated the function of male hearing for the sarcophagid fly Emblemasoma erro Aldrich, an acoustic parasitoid of cicadas, by testing the hypothesis that both male and female E. erro use hearing to locate potential mates. I found that both male and nongravid female E. erro perform phonotaxis to the sounds of calling cicadas, that male flies engage in short-range, mate-finding behavior once they arrive at a sound source, and that encounters between females and males at a sound source can lead to copulation. Thus, cicada calling songs appear to serve as a mate-finding cue for both sexes of E. erro Emblemasoma erro's mate-finding behavior is compared to that of other sarcophagid flies, other acoustic parasitoids, and nonacoustic eavesdropping parasitoids. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

Negative mood and mind wandering increase long-range temporal correlations in attention fluctuations.

PubMed

Irrmischer, Mona; van der Wal, C Natalie; Mansvelder, Huibert D; Linkenkaer-Hansen, Klaus

2018-01-01

There is growing evidence that the intermittent nature of mind wandering episodes and mood have a pronounced influence on trial-to-trial variability in performance. Nevertheless, the temporal dynamics and significance of such lapses in attention remains inadequately understood. Here, we hypothesize that the dynamics of fluctuations in sustained attention between external and internal sources of information obey so-called critical-state dynamics, characterized by trial-to-trial dependencies with long-range temporal correlations. To test this, we performed behavioral investigations measuring reaction times in a visual sustained attention task and cued introspection in probe-caught reports of mind wandering. We show that trial-to-trial variability in reaction times exhibit long-range temporal correlations in agreement with the criticality hypothesis. Interestingly, we observed the fastest responses in subjects with the weakest long-range temporal correlations and show the vital effect of mind wandering and bad mood on this response variability. The implications of these results stress the importance of future research to increase focus on behavioral variability.

Negative mood and mind wandering increase long-range temporal correlations in attention fluctuations

PubMed Central

van der Wal, C. Natalie; Mansvelder, Huibert D.; Linkenkaer-Hansen, Klaus

2018-01-01

There is growing evidence that the intermittent nature of mind wandering episodes and mood have a pronounced influence on trial-to-trial variability in performance. Nevertheless, the temporal dynamics and significance of such lapses in attention remains inadequately understood. Here, we hypothesize that the dynamics of fluctuations in sustained attention between external and internal sources of information obey so-called critical-state dynamics, characterized by trial-to-trial dependencies with long-range temporal correlations. To test this, we performed behavioral investigations measuring reaction times in a visual sustained attention task and cued introspection in probe-caught reports of mind wandering. We show that trial-to-trial variability in reaction times exhibit long-range temporal correlations in agreement with the criticality hypothesis. Interestingly, we observed the fastest responses in subjects with the weakest long-range temporal correlations and show the vital effect of mind wandering and bad mood on this response variability. The implications of these results stress the importance of future research to increase focus on behavioral variability. PMID:29746529

Recent Advances in Omega-3: Health Benefits, Sources, Products and Bioavailability

PubMed Central

Nichols, Peter D.; McManus, Alexandra; Krail, Kevin; Sinclair, Andrew J.; Miller, Matt

2014-01-01

The joint symposium of The Omega-3 Centre and the Australasian Section American Oil Chemists Society; Recent Advances in Omega-3: Health Benefits, Sources, Products and Bioavailability, was held November 7, 2013 in Newcastle, NSW, Australia. Over 115 attendees received new information on a range of health benefits, aquaculture as a sustainable source of supply, and current and potential new and novel sources of these essential omega-3 long-chain (LC, ≥C20) polyunsaturated fatty acid nutrients (also termed LC omega-3). The theme of “Food versus Fuel” was an inspired way to present a vast array of emerging and ground breaking Omega-3 research that has application across many disciplines. Eleven papers submitted following from the Omega-3 Symposium are published in this Special Issue volume, with topics covered including: an update on the use of the Omega-3 Index (O3I), the effects of dosage and concurrent intake of vitamins/minerals on omega-3 incorporation into red blood cells, the possible use of the O3I as a measure of risk for adiposity, the need for and progress with new land plant sources of docosahexaenoic acid (DHA, 22:6ω3), the current status of farmed Australian and New Zealand fish, and also supplements, in terms of their LC omega-3 and persistent organic pollutants (POP) content, progress with cheap carbon sources in the culture of DHA-producing single cell organisms, a detailed examination of the lipids of the New Zealand Greenshell mussel, and a pilot investigation of the purification of New Zealand hoki liver oil by short path distillation. The selection of papers in this Special Issue collectively highlights a range of forward looking and also new and including positive scientific outcomes occurring in the omega-3 field. PMID:25255830

Recent advances in omega-3: Health Benefits, Sources, Products and Bioavailability.

PubMed

Nichols, Peter D; McManus, Alexandra; Krail, Kevin; Sinclair, Andrew J; Miller, Matt

2014-09-16

The joint symposium of The Omega-3 Centre and the Australasian Section American Oil Chemists Society; Recent Advances in Omega-3: Health Benefits, Sources, Products and Bioavailability, was held November 7, 2013 in Newcastle, NSW, Australia. Over 115 attendees received new information on a range of health benefits, aquaculture as a sustainable source of supply, and current and potential new and novel sources of these essential omega-3 long-chain (LC, ≥ C20) polyunsaturated fatty acid nutrients (also termed LC omega-3). The theme of "Food versus Fuel" was an inspired way to present a vast array of emerging and ground breaking Omega-3 research that has application across many disciplines. Eleven papers submitted following from the Omega-3 Symposium are published in this Special Issue volume, with topics covered including: an update on the use of the Omega-3 Index (O3I), the effects of dosage and concurrent intake of vitamins/minerals on omega-3 incorporation into red blood cells, the possible use of the O3I as a measure of risk for adiposity, the need for and progress with new land plant sources of docosahexaenoic acid (DHA, 22:6ω3), the current status of farmed Australian and New Zealand fish, and also supplements, in terms of their LC omega-3 and persistent organic pollutants (POP) content, progress with cheap carbon sources in the culture of DHA-producing single cell organisms, a detailed examination of the lipids of the New Zealand Greenshell mussel, and a pilot investigation of the purification of New Zealand hoki liver oil by short path distillation. The selection of papers in this Special Issue collectively highlights a range of forward looking and also new and including positive scientific outcomes occurring in the omega-3 field.

CRUSTAL REFRACTION PROFILE OF THE LONG VALLEY CALDERA, CALIFORNIA, FROM THE JANUARY 1983 MAMMOTH LAKES EARTHQUAKE SWARM.

USGS Publications Warehouse

Luetgert, James H.; Mooney, Walter D.

1985-01-01

Seismic-refraction profiles recorded north of Mammoth Lakes, California, using earthquake sources from the January 1983 swarm complement earlier explosion refraction profiles and provide velocity information from deeper in the crust in the area of the Long Valley caldera. Eight earthquakes from a depth range of 4. 9 to 8. 0 km confirm the observation of basement rocks with seismic velocities ranging from 5. 8 to 6. 4 km/sec extending at least to depths of 20 km. The data provide further evidence for the existence of a partial melt zone beneath Long Valley caldera and constrain its geometry. Refs.

Simple and versatile long range swept source for optical coherence tomography applications

NASA Astrophysics Data System (ADS)

Bräuer, Bastian; Lippok, Norman; Murdoch, Stuart G.; Vanholsbeeck, Frédérique

2015-12-01

We present a versatile long coherence length swept-source laser design for optical coherence tomography applications. This design consists of a polygonal spinning mirror and an optical gain chip in a modified Littman-Metcalf cavity. A narrowband intra-cavity filter is implemented through multiple passes off a diffraction grating set at grazing incidence. The key advantage of this design is that it can be readily adapted to any wavelength regions for which broadband gain chips are available. We demonstrate this by implementing sources at 1650 nm, 1550 nm, 1310 nm and 1050 nm. In particular, we present a 1310 nm swept source laser with 24 mm coherence length, 95 nm optical bandwidth, 2 kHz maximum sweep frequency and 7.5 mW average output power. These parameters make it a suitable source for the imaging of biological samples.

Evaluating the potential energy landscape over single molecules at room temperature with lateral force microscopy

NASA Astrophysics Data System (ADS)

Weymouth, Alfred J.; Riegel, Elisabeth; Matencio, Sonia; Giessibl, Franz J.

2018-04-01

One of the challenges of AFM, in contrast to STM, is that the measured signal includes both long-range and short-range components. The most accurate method for removing long-range components is to measure both on and off an adsorbate and to subtract the difference. This on-off method is challenging at room temperature due to thermal drift. By moving to a non-contact scheme in which the lateral component of the force interaction is probed, the measurement is dominated by short-range interactions. We use frequency-modulation lateral force microscopy to measure individual PTCDA molecules adsorbed on Ag/Si(111)-( √{3 }×√{3 } ). By fitting the data to a model potential, we can extract the depth and width of the potential. When the tip is closer to the sample, a repulsive feature can be observed in the data.

Source apportionment of fine particulate matter measured in an industrialized coastal urban area of South Texas

NASA Astrophysics Data System (ADS)

Karnae, Saritha; John, Kuruvilla

2011-07-01

Corpus Christi is a growing industrialized urban airshed in South Texas impacted by local emissions and regional transport of fine particulate matter (PM 2.5). Positive matrix factorization (PMF2) technique was used to evaluate particulate matter pollution in the urban airshed by estimating the types of sources and its corresponding mass contributions affecting the measured ambient PM 2.5 levels. Fine particulate matter concentrations by species measured during July 2003 through December 2008 at a PM 2.5 speciation site were used in this study. PMF2 identified eight source categories, of which secondary sulfates were the dominant source category accounting for 30.4% of the apportioned mass. The other sources identified included aged sea salt (18.5%), biomass burns (12.7%), crustal dust (10.1%), traffic (9.7%), fresh sea salt (8.1%), industrial sources (6%), and a co-mingled source of oil combustion & diesel emissions (4.6%). The apportioned PM mass showed distinct seasonal variability between source categories. The PM levels in Corpus Christi were affected by biomass burns in Mexico and Central America during April and May, sub-Saharan dust storms from Africa during the summer months, and a continental haze episode during August and September with significant transport from the highly industrialized areas of Texas and the neighboring states. Potential source contribution function (PSCF) analysis was performed and it identified source regions and the influence of long-range transport of fine particulate matter affecting this urban area.

Industrial ion source technology. [for ion beam etching, surface texturing, and deposition

NASA Technical Reports Server (NTRS)

Kaufman, H. R.

1977-01-01

Plasma probe surveys were conducted in a 30-cm source to verify that the uniformity in the ion beam is the result of a corresponding uniformity in the discharge-chamber plasma. A 15 cm permanent magnet multipole ion source was designed, fabricated, and demonstrated. Procedures were investigated for texturing a variety of seed and surface materials for controlling secondary electron emission, increasing electron absorption of light, and improved attachment of biological tissue for medical implants using argon and tetrafluoromethane as the working gases. The cross section for argon-argon elastic collisions in the ion-beam energy range was calculated from interaction potentials and permits calculation of beam interaction effects that can determine system pumping requirements. The data also indicate that different optimizations of ion-beam machines will be advantageous for long and short runs, with 1 mA-hr/cm being the rough dividing line for run length. The capacity to simultaneously optimize components in an ion-beam machine for a single application, a capacity that is not evident in competitive approaches such as diode sputtering is emphasized.

Chemistry and Photochemistry at the Surface of Urban Road Dust and Photoactive Minerals

NASA Astrophysics Data System (ADS)

Styler, S. A.; Abou-Ghanem, M.; Wickware, B.

2017-12-01

Each year, over a billion tons of dust are released into the atmosphere from arid regions. After its emission, dust can undergo efficient long-range transport to urban centres, where it can interact with local pollution sources. Another source of dust in urban regions is road dust resuspension, which is the largest anthropogenic source of primary particulate matter in both Canada and the United States. Since dust contains light-absorbing components, including iron- and titanium-containing minerals, dust-catalyzed photochemical processes have the potential to influence both the lifetime of pollutants present at the dust surface and the composition of the surrounding atmosphere. To date, most studies of dust photochemistry have focused on TiO2-mediated processes, and no studies have explored trace gas uptake at the surface of road dust. Here, we present first results from aerosol and coated-wall flow tube investigations of ozone uptake at the surface of a suite of titanium-containing minerals and road dust collected in Edmonton, Alberta. Together, this work represents a significant advance in our understanding of chemistry and photochemistry at realistic environmental interfaces.

A study of infrasound propagation based on high-order finite difference solutions of the Navier-Stokes equations.

PubMed

Marsden, O; Bogey, C; Bailly, C

2014-03-01

The feasibility of using numerical simulation of fluid dynamics equations for the detailed description of long-range infrasound propagation in the atmosphere is investigated. The two dimensional (2D) Navier Stokes equations are solved via high fidelity spatial finite differences and Runge-Kutta time integration, coupled with a shock-capturing filter procedure allowing large amplitudes to be studied. The accuracy of acoustic prediction over long distances with this approach is first assessed in the linear regime thanks to two test cases featuring an acoustic source placed above a reflective ground in a homogeneous and weakly inhomogeneous medium, solved for a range of grid resolutions. An atmospheric model which can account for realistic features affecting acoustic propagation is then described. A 2D study of the effect of source amplitude on signals recorded at ground level at varying distances from the source is carried out. Modifications both in terms of waveforms and arrival times are described.

Back-Projection Imaging of extended, diffuse seismic sources in volcanic and hydrothermal systems

NASA Astrophysics Data System (ADS)

Kelly, C. L.; Lawrence, J. F.; Beroza, G. C.

2017-12-01

Volcanic and hydrothermal systems exhibit a wide range of seismicity that is directly linked to fluid and volatile activity in the subsurface and that can be indicative of imminent hazardous activity. Seismograms recorded near volcanic and hydrothermal systems typically contain "noisy" records, but in fact, these complex signals are generated by many overlapping low-magnitude displacements and pressure changes at depth. Unfortunately, excluding times of high-magnitude eruptive activity that typically occur infrequently relative to the length of a system's entire eruption cycle, these signals often have very low signal-to-noise ratios and are difficult to identify and study using established seismic analysis techniques (i.e. phase-picking, template matching). Arrays of short-period and broadband seismic sensors are proven tools for monitoring short- and long-term changes in volcanic and hydrothermal systems. Time-reversal techniques (i.e. back-projection) that are improved by additional seismic observations have been successfully applied to locating volcano-seismic sources recorded by dense sensor arrays. We present results from a new computationally efficient back-projection method that allows us to image the evolution of extended, diffuse sources of volcanic and hydrothermal seismicity. We correlate short time-window seismograms from receiver-pairs to find coherent signals and propagate them back in time to potential source locations in a 3D subsurface model. The strength of coherent seismic signal associated with any potential source-receiver-receiver geometry is equal to the correlation of the short time-windows of seismic records at appropriate time lags as determined by the velocity structure and ray paths. We stack (sum) all short time-window correlations from all receiver-pairs to determine the cumulative coherence of signals at each potential source location. Through stacking, coherent signals from extended and/or repeating sources of short-period energy radiation interfere constructively while background noise signals interfere destructively, such that the most likely source locations of the observed seismicity are illuminated. We compile results to analyze changes in the distribution and prevalence of these sources throughout a systems entire eruptive cycle.

Liquid metal ion source and alloy

DOEpatents

Clark, Jr., William M.; Utlaut, Mark W.; Behrens, Robert G.; Szklarz, Eugene G.; Storms, Edmund K.; Santandrea, Robert P.; Swanson, Lynwood W.

1988-10-04

A liquid metal ion source and alloy, wherein the species to be emitted from the ion source is contained in a congruently vaporizing alloy. In one embodiment, the liquid metal ion source acts as a source of arsenic, and in a source alloy the arsenic is combined with palladium, preferably in a liquid alloy having a range of compositions from about 24 to about 33 atomic percent arsenic. Such an alloy may be readily prepared by a combustion synthesis technique. Liquid metal ion sources thus prepared produce arsenic ions for implantation, have long lifetimes, and are highly stable in operation.

Increasing the dynamic range of CMOS photodiode imagers

NASA Technical Reports Server (NTRS)

Pain, Bedabrata (Inventor); Cunningham, Thomas J. (Inventor); Hancock, Bruce R. (Inventor)

2007-01-01

A multiple-step reset process and circuit for resetting a voltage stored on a photodiode of an imaging device. A first stage of the reset occurs while a source and a drain of a pixel source-follower transistor are held at ground potential and the photodiode and a gate of the pixel source-follower transistor are charged to an initial reset voltage having potential less that of a supply voltage. A second stage of the reset occurs after the initial reset voltage is stored on the photodiode and the gate of the pixel source-follower transistor and the source and drain voltages of the pixel source-follower transistor are released from ground potential thereby allowing the source and drain voltages of the pixel source-follower transistor to assume ordinary values above ground potential and resulting in a capacitive feed-through effect that increases the voltage on the photodiode to a value greater than the initial reset voltage.

Provenance analysis of the Pliocene Ware Formation in the Guajira Peninsula, northern Colombia: Paleodrainage implications

NASA Astrophysics Data System (ADS)

Pérez-Consuegra, Nicolás; Parra, Mauricio; Jaramillo, Carlos; Silvestro, Daniele; Echeverri, Sebastián; Montes, Camilo; Jaramillo, José María; Escobar, Jaime

2018-01-01

The Cocinetas Basin in the Guajira Peninsula, the northernmost tip of South America, today has a dry climate with low rainfall (<500 mm/yr), a long dry season (>ten months) and no year-long rivers or permanent standing bodies of fresh water. In contrast, the fossil and geological record indicate that the Cocinetas Basin was much wetter during the Miocene-Pliocene (∼17-2.8 Ma). Water needed to sustain the paleofauna could either have originated from local sources or been brought by a larger river system (e.g. proto Magdalena/Orinoco river) with headwaters either in Andean ranges or the Guyana shield. We present a provenance study of the Pliocene Ware Formation, using petrographic analysis of conglomerate clasts and heavy minerals, and U-Pb dating of 140 detrital zircons. Clasts and heavy minerals are typical of ensialic metamorphic and igneous sources. The detrital zircon age distribution indicates the Guajira ranges as the most probable sediment source. The overall results indicate that the fluvial system of the Ware Formation drained the surrounding ranges. The water was probably derived by local precipitation onto the Guajira peninsula.

Long-distance Lienard-Wiechert potentials and qq-bar spin dependence

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

Childers, R.W.

1987-12-15

The long-range spin dependence of the qq interaction is considered in a model in which the confining potential is required to be the static limit of retarded scalar and vector potentials analogous to the Lienard-Wiechert potentials of classical electrodynamics. A generalization of Darwin's method is used to obtain the corresponding Hamiltonian. The long-distance spin-dependent interaction is found to be determined completely by only two potentials: namely, the static scalar and vector potentials. This is to be compared with the four potentials required in Eichten and Feinberg's general formulation. Two different solutions are allowed by Gromes's theorem. In one, the scalarmore » potential can be linear; in the other, it must be logarithmic.« less

Bounds on Energy Absorption and Prethermalization in Quantum Systems with Long-Range Interactions

NASA Astrophysics Data System (ADS)

Ho, Wen Wei; Protopopov, Ivan; Abanin, Dmitry A.

2018-05-01

Long-range interacting systems such as nitrogen vacancy centers in diamond and trapped ions serve as experimental setups to probe a range of nonequilibrium many-body phenomena. In particular, via driving, various effective Hamiltonians with physics potentially quite distinct from short-range systems can be realized. In this Letter, we derive general rigorous bounds on the linear response energy absorption rates of periodically driven systems of spins or fermions with long-range interactions that are sign changing and fall off as 1 /rα with α >d /2 . We show that the disorder averaged energy absorption rate at high temperatures decays exponentially with the driving frequency. This strongly suggests the presence of a prethermal plateau in which dynamics is governed by an effective, static Hamiltonian for long times, and we provide numerical evidence to support such a statement. Our results are relevant for understanding timescales of heating and new dynamical regimes described by effective Hamiltonians in such long-range systems.

Characterization of VOC sources in an urban area based on PTR-MS measurements and receptor modelling.

PubMed

Stojić, A; Stojić, S Stanišić; Šoštarić, A; Ilić, L; Mijić, Z; Rajšić, S

2015-09-01

In this study, the concentrations of volatile organic compounds were measured by the use of proton transfer reaction mass spectrometry, together with NO x , NO, NO2, SO2, CO and PM10 and meteorological parameters in an urban area of Belgrade during winter 2014. The multivariate receptor model US EPA Unmix was applied to the obtained dataset resolving six source profiles, which can be attributed to traffic-related emissions, gasoline evaporation/oil refineries, petrochemical industry/biogenic emissions, aged plumes, solid-fuel burning and local laboratories. Besides the vehicle exhaust, accounting for 27.6 % of the total mixing ratios, industrial emissions, which are present in three out of six resolved profiles, exert a significant impact on air quality in the urban area. The major contribution of regional and long-range transport was determined for source profiles associated with petrochemical industry/biogenic emissions (40 %) and gasoline evaporation/oil refineries (29 %) using trajectory sector analysis. The concentration-weighted trajectory model was applied with the aim of resolving the spatial distribution of potential distant sources, and the results indicated that emission sources from neighbouring countries, as well as from Slovakia, Greece, Poland and Scandinavian countries, significantly contribute to the observed concentrations.

Health Impact of PM10, PM2.5 and Black Carbon Exposure Due to Different Source Sectors in Stockholm, Gothenburg and Umea, Sweden

PubMed Central

Eneroth, Kristina; Gidhagen, Lars; Johansson, Christer; Omstedt, Gunnar; Engström Nylén, Anders; Forsberg, Bertil

2017-01-01

The most important anthropogenic sources of primary particulate matter (PM) in ambient air in Europe are exhaust and non-exhaust emissions from road traffic and combustion of solid biomass. There is convincing evidence that PM, almost regardless of source, has detrimental health effects. An important issue in health impact assessments is what metric, indicator and exposure-response function to use for different types of PM. The aim of this study is to describe sectorial contributions to PM exposure and related premature mortality for three Swedish cities: Gothenburg, Stockholm and Umea. Exposure is calculated with high spatial resolution using atmospheric dispersion models. Attributed premature mortality is calculated separately for the main local sources and the contribution from long-range transport (LRT), applying different relative risks. In general, the main part of the exposure is due to LRT, while for black carbon, the local sources are equally or more important. The major part of the premature deaths is in our assessment related to local emissions, with road traffic and residential wood combustion having the largest impact. This emphasizes the importance to resolve within-city concentration gradients when assessing exposure. It also implies that control actions on local PM emissions have a strong potential in abatement strategies. PMID:28686215

Wide field and highly sensitive angiography based on optical coherence tomography with akinetic swept source.

PubMed

Xu, Jingjiang; Song, Shaozhen; Wei, Wei; Wang, Ruikang K

2017-01-01

Wide-field vascular visualization in bulk tissue that is of uneven surface is challenging due to the relatively short ranging distance and significant sensitivity fall-off for most current optical coherence tomography angiography (OCTA) systems. We report a long ranging and ultra-wide-field OCTA (UW-OCTA) system based on an akinetic swept laser. The narrow instantaneous linewidth of the swept source with its high phase stability, combined with high-speed detection in the system enable us to achieve long ranging (up to 46 mm) and almost negligible system sensitivity fall-off. To illustrate these advantages, we compare the basic system performances between conventional spectral domain OCTA and UW-OCTA systems and their functional imaging of microvascular networks in living tissues. In addition, we show that the UW-OCTA is capable of different depth-ranging of cerebral blood flow within entire brain in mice, and providing unprecedented blood perfusion map of human finger in vivo . We believe that the UW-OCTA system has promises to augment the existing clinical practice and explore new biomedical applications for OCT imaging.

Wide field and highly sensitive angiography based on optical coherence tomography with akinetic swept source

PubMed Central

Xu, Jingjiang; Song, Shaozhen; Wei, Wei; Wang, Ruikang K.

2016-01-01

Wide-field vascular visualization in bulk tissue that is of uneven surface is challenging due to the relatively short ranging distance and significant sensitivity fall-off for most current optical coherence tomography angiography (OCTA) systems. We report a long ranging and ultra-wide-field OCTA (UW-OCTA) system based on an akinetic swept laser. The narrow instantaneous linewidth of the swept source with its high phase stability, combined with high-speed detection in the system enable us to achieve long ranging (up to 46 mm) and almost negligible system sensitivity fall-off. To illustrate these advantages, we compare the basic system performances between conventional spectral domain OCTA and UW-OCTA systems and their functional imaging of microvascular networks in living tissues. In addition, we show that the UW-OCTA is capable of different depth-ranging of cerebral blood flow within entire brain in mice, and providing unprecedented blood perfusion map of human finger in vivo. We believe that the UW-OCTA system has promises to augment the existing clinical practice and explore new biomedical applications for OCT imaging. PMID:28101428

Spatial analysis of factors influencing long-term stress in the grizzly bear (Ursus arctos) population of Alberta, Canada.

PubMed

Bourbonnais, Mathieu L; Nelson, Trisalyn A; Cattet, Marc R L; Darimont, Chris T; Stenhouse, Gordon B

2013-01-01

Non-invasive measures for assessing long-term stress in free ranging mammals are an increasingly important approach for understanding physiological responses to landscape conditions. Using a spatially and temporally expansive dataset of hair cortisol concentrations (HCC) generated from a threatened grizzly bear (Ursus arctos) population in Alberta, Canada, we quantified how variables representing habitat conditions and anthropogenic disturbance impact long-term stress in grizzly bears. We characterized spatial variability in male and female HCC point data using kernel density estimation and quantified variable influence on spatial patterns of male and female HCC stress surfaces using random forests. Separate models were developed for regions inside and outside of parks and protected areas to account for substantial differences in anthropogenic activity and disturbance within the study area. Variance explained in the random forest models ranged from 55.34% to 74.96% for males and 58.15% to 68.46% for females. Predicted HCC levels were higher for females compared to males. Generally, high spatially continuous female HCC levels were associated with parks and protected areas while low-to-moderate levels were associated with increased anthropogenic disturbance. In contrast, male HCC levels were low in parks and protected areas and low-to-moderate in areas with increased anthropogenic disturbance. Spatial variability in gender-specific HCC levels reveal that the type and intensity of external stressors are not uniform across the landscape and that male and female grizzly bears may be exposed to, or perceive, potential stressors differently. We suggest observed spatial patterns of long-term stress may be the result of the availability and distribution of foods related to disturbance features, potential sexual segregation in available habitat selection, and may not be influenced by sources of mortality which represent acute traumas. In this wildlife system and others, conservation and management efforts can benefit by understanding spatial- and gender-based stress responses to landscape conditions.

Spatial Analysis of Factors Influencing Long-Term Stress in the Grizzly Bear (Ursus arctos) Population of Alberta, Canada

PubMed Central

Bourbonnais, Mathieu L.; Nelson, Trisalyn A.; Cattet, Marc R. L.; Darimont, Chris T.; Stenhouse, Gordon B.

2013-01-01

Non-invasive measures for assessing long-term stress in free ranging mammals are an increasingly important approach for understanding physiological responses to landscape conditions. Using a spatially and temporally expansive dataset of hair cortisol concentrations (HCC) generated from a threatened grizzly bear (Ursus arctos) population in Alberta, Canada, we quantified how variables representing habitat conditions and anthropogenic disturbance impact long-term stress in grizzly bears. We characterized spatial variability in male and female HCC point data using kernel density estimation and quantified variable influence on spatial patterns of male and female HCC stress surfaces using random forests. Separate models were developed for regions inside and outside of parks and protected areas to account for substantial differences in anthropogenic activity and disturbance within the study area. Variance explained in the random forest models ranged from 55.34% to 74.96% for males and 58.15% to 68.46% for females. Predicted HCC levels were higher for females compared to males. Generally, high spatially continuous female HCC levels were associated with parks and protected areas while low-to-moderate levels were associated with increased anthropogenic disturbance. In contrast, male HCC levels were low in parks and protected areas and low-to-moderate in areas with increased anthropogenic disturbance. Spatial variability in gender-specific HCC levels reveal that the type and intensity of external stressors are not uniform across the landscape and that male and female grizzly bears may be exposed to, or perceive, potential stressors differently. We suggest observed spatial patterns of long-term stress may be the result of the availability and distribution of foods related to disturbance features, potential sexual segregation in available habitat selection, and may not be influenced by sources of mortality which represent acute traumas. In this wildlife system and others, conservation and management efforts can benefit by understanding spatial- and gender-based stress responses to landscape conditions. PMID:24386273

Historical comparisons reveal multiple drivers of decadal change of an ecosystem engineer at the range edge

PubMed Central

Firth, Louise B; Mieszkowska, Nova; Grant, Lisa M; Bush, Laura E; Davies, Andrew J; Frost, Matthew T; Moschella, Paula S; Burrows, Michael T; Cunningham, Paul N; Dye, Stephen R; Hawkins, Stephen J

2015-01-01

Biogenic reefs are important for habitat provision and coastal protection. Long-term datasets on the distribution and abundance of Sabellaria alveolata (L.) are available from Britain. The aim of this study was to combine historical records and contemporary data to (1) describe spatiotemporal variation in winter temperatures, (2) document short-term and long-term changes in the distribution and abundance of S. alveolata and discuss these changes in relation to extreme weather events and recent warming, and (3) assess the potential for artificial coastal defense structures to function as habitat for S. alveolata. A semi-quantitative abundance scale (ACFOR) was used to compare broadscale, long-term and interannual abundance of S. alveolata near its range edge in NW Britain. S. alveolata disappeared from the North Wales and Wirral coastlines where it had been abundant prior to the cold winter of 1962/1963. Population declines were also observed following the recent cold winters of 2009/2010 and 2010/2011. Extensive surveys in 2004 and 2012 revealed that S. alveolata had recolonized locations from which it had previously disappeared. Furthermore, it had increased in abundance at many locations, possibly in response to recent warming. S. alveolata was recorded on the majority of artificial coastal defense structures surveyed, suggesting that the proliferation of artificial coastal defense structures along this stretch of coastline may have enabled S. alveolata to spread across stretches of unsuitable natural habitat. Long-term and broadscale contextual monitoring is essential for monitoring responses of organisms to climate change. Historical data and gray literature can be invaluable sources of information. Our results support the theory that Lusitanian species are responding positively to climate warming but also that short-term extreme weather events can have potentially devastating widespread and lasting effects on organisms. Furthermore, the proliferation of coastal defense structures has implications for phylogeography, population genetics, and connectivity of coastal populations. PMID:26355379

Repulsive Casimir-Polder potential by a negative reflecting surface

NASA Astrophysics Data System (ADS)

Yuan, Qi-Zhang

2015-07-01

We present a scheme to generate an all-range long repulsive Casimir-Polder potential between a perfect negative reflecting surface and a ground-state atom. The repulsive potential is stable and does not decay with time. The Casimir-Polder potential is proportional to z-2 at short atom-surface distances and to z-4 at long atom-surface distances. Because of these advantages, this potential can help in building quantum reflectors, quantum levitating devices, and waveguides for matter waves.

Impact of Convection and Long Range Transport on Short-Lived Trace Gases in the UT/LS

NASA Astrophysics Data System (ADS)

Atlas, E. L.; Schauffler, S.; Navarro, M. A.; Lueb, R.; Hendershot, R.; Ueyama, R.

2017-12-01

Chemical composition of the air in the upper troposphere/lower stratosphere is controlled by a balance of transport, photochemistry, and physical processes, such as interactions with clouds, ice, and aerosol. The chemistry of the air masses that reach the upper troposphere can potentially have profound impacts on the chemistry in the near tropopause region. For example, the transport of reactive organic halogens and their transformation to inorganic halogen species, e.g., Br, BrO, etc., can have a significant impact on ozone budgets in this region and even deeper the stratosphere. Trace gas measurements in the region near the tropopause can also indicate potential sources of surface emissions that are transported to high altitudes. Measurement of trace gases, including such compounds as non-methane hydrocarbons, hydrochlorofluorocarbons, halogenated solvents, methyl halides, etc., can be used to characterize source emissions from industrial, urban, biomass burning, or marine origins. Recent airborne research campaigns have been conducted to better characterize the chemical composition and variations in the UT/LS region. This presentation will discuss these measurements, with a special emphasis on the role of convection and transport in modifying the chemical composition of the UT/LS.

Modeling atmospheric effects - an assessment of the problems

Treesearch

Douglas G. Fox

1976-01-01

Our ability to simulate atmospheric processes that affect the life cycle of pollution is reviewed. The transport process is considered on three scales (a) the near-source or single-plume dispersion problem, (b) the multiple-source dispersion problem, and (c) the long-range transport. Modeling the first of these is shown to be well within the capability of generally...

Analytic Empirical Potentials for all Stable Isotopologues of the Ground X(^1Σ^+) State of ZnO from Purely Rotational Measurements

NASA Astrophysics Data System (ADS)

Dattani, Nikesh S.; Zack, Lindsay; Sun, Ming; Johnson, Erin R.; Le Roy, Robert; Ziurys, Lucy

2014-06-01

We report eight new ultra-high precision (±5 kHz) measurements of purely rotational N(1←0) transitions in several vibrational states of all stable isotopologues of the ground X(11Σ+) -state of ZnO. Combined with previous high-resolution (±50 kHz) measurements of purely rotational transitions between higher rotational states for the same system, we are able to build analytic potentials for 64Zn16O, 66Zn16O, 67Zn16O, 68Zn16O, and 70Zn16O, that are in full agreement with all known spectroscopic measurements of the system. Despite there being absolutely no vibrational information, our empirical potentials are able to determine the size of the vibrational spacings and the bond lengths, each with a precision of more than two orders of magnitude greater than the most precise empirical values previously known. We then use the XDM method to calculate values for the C6, C8, and C10 long-range constants for this molecule, and use these to accurately anchor the long-range regions of the potentials, where no measurements have yet been performed. In the region lying between the short-range measurements and the long-range theory on which our potentials are based, our final analytic global potentials are in very good agreement with state of the art ab initio potentials. L. N. Zack, R. L. Pulliam, L. M. Ziurys, J. Mol. Spec., 256, 186-191 (2009).

Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions.

PubMed

Wang, Yimin; Bowman, Joel M; Kamarchik, Eugene

2016-03-21

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na(+)H2O, F(-)H2O, and Cl(-)H2O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H2O potentials are permutationally invariant fits to roughly 20,000 coupled cluster CCSD(T) energies (awCVTZ basis for Na(+) and aVTZ basis for Cl(-) and F(-)), over a large range of distances and H2O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.

Origins of aerosol chlorine during winter over north central Colorado, USA

NASA Astrophysics Data System (ADS)

Jordan, C. E.; Pszenny, A. A. P.; Keene, W. C.; Cooper, O. R.; Deegan, B.; Maben, J.; Routhier, M.; Sander, R.; Young, A. H.

2015-01-01

The Nitrogen, Aerosol Composition, and Halogens on a Tall Tower campaign (February-March 2011) near Boulder, Colorado, investigated nighttime ClNO2 production and processing. Virtually all particulate Cl was in the form of ionic Cl-. The size distributions of Cl- and Na+ were similar, with most of the mass in the supermicrometer size fraction, suggesting primary sources for both. Median Cl- concentrations were about half those of Na+ and Ca2+ for particle diameters centered at 1.4 and 2.5 µm. To investigate potential sources of Na+ and Cl-, four cases were studied that featured the prevalence of Na+ and Cl- and different transport pathways based on FLEXible PARTicle dispersion model (FLEXPART) retroplumes. Estimates of supermicrometer Na+ particle lifetime against deposition indicate that long-range transport of marine aerosols could account for the observed Na+. However, measured molar ratios of Ca2+ to Na+ (0.143-0.588) compared to seawater (0.022) indicate significant contributions from crustal sources to the supermicrometer aerosol composition during these four case studies. Further, low molar ratios of Mg2+ to Na+ (0.007-0.098) relative to seawater (0.114) suggest that some of the Na+, and presumably associated Cl-, originated from non-sea-salt sources. The heterogeneous chemical composition of saline soils throughout the western U.S., along with the nonlinearity of wind-driven soil deflation as a function of various surface soil properties, precludes a quantitative apportionment of soil, marine, and anthropogenic sources to the observed coarse-fraction aerosol. Nonetheless, results suggest that deflation of saline soils was a potentially important source of particulate Cl- that sustained atmospheric ClNO2 production and associated impacts on oxidation processes over northern Colorado.

Seasonal associations and atmospheric transport distances of fungi in the genus Fusarium collected with unmanned aerial vehicles and ground-based sampling devices

NASA Astrophysics Data System (ADS)

Lin, Binbin; Ross, Shane D.; Prussin, Aaron J.; Schmale, David G.

2014-09-01

Spores of fungi in the genus Fusarium may be transported through the atmosphere over long distances. New information is needed to characterize seasonal trends in atmospheric loads of Fusarium and to pinpoint the source(s) of inoculum at both local (farm) and regional (state or country) scales. We hypothesized that (1) atmospheric concentrations of Fusarium spores in an agricultural ecosystem vary with height and season and (2) transport distances from potential inoculum source(s) vary with season. To test these hypotheses, spores of Fusarium were collected from the atmosphere in an agricultural ecosystem in Blacksburg, VA, USA using a Burkard volumetric sampler (BVS) 1 m above ground level and autonomous unmanned aerial vehicles (UAVs) 100 m above ground level. More than 2200 colony forming units (CFUs) of Fusarium were collected during 104 BVS sampling periods and 180 UAV sampling periods over four calendar years (2009-2012). Spore concentrations ranged from 0 to 13 and 0 to 23 spores m-3 for the BVS and the UAVs, respectively. Spore concentrations were generally higher in the fall, spring, and summer, and lower in the winter. Spore concentrations from the BVS were generally higher than those from the UAVs for both seasonal and hourly collections. A Gaussian plume transport model was used to estimate distances to the potential inoculum source(s) by season, and produced mean transport distances of 1.4 km for the spring, 1.7 km for the summer, 1.2 km for the fall, and 4.1 km for the winter. Environmental signatures that predict atmospheric loads of Fusarium could inform disease spread, air pollution, and climate change.

Theoretical Studies of Kinetic Mechanisms of Negative Ion Formation in Plasmas.

DTIC Science & Technology

1987-06-01

927258 ILLUSTRATIONS Figure Title Pg e 1 Long-Range Behavior of Excited IVg States of Li2 21 . 2 Long-Range Behavior of Excited It* States of Li2 22U 2 3...34) yields a statistically better fit with X2 - 0.002 as compared to X2 - 0.01 for the Ceperley and Partridge potential (Ref. 24). A significantly...including those reported by Jordan and Amdur (Ref. 37), yield significantly poorer statistical fits. We have not analyzed the new potential of Nitz, et

Magnetic metamaterial superlens for increased range wireless power transfer.

PubMed

Lipworth, Guy; Ensworth, Joshua; Seetharam, Kushal; Huang, Da; Lee, Jae Seung; Schmalenberg, Paul; Nomura, Tsuyoshi; Reynolds, Matthew S; Smith, David R; Urzhumov, Yaroslav

2014-01-10

The ability to wirelessly power electrical devices is becoming of greater urgency as a component of energy conservation and sustainability efforts. Due to health and safety concerns, most wireless power transfer (WPT) schemes utilize very low frequency, quasi-static, magnetic fields; power transfer occurs via magneto-inductive (MI) coupling between conducting loops serving as transmitter and receiver. At the "long range" regime - referring to distances larger than the diameter of the largest loop - WPT efficiency in free space falls off as (1/d)(6); power loss quickly approaches 100% and limits practical implementations of WPT to relatively tight distances between power source and device. A "superlens", however, can concentrate the magnetic near fields of a source. Here, we demonstrate the impact of a magnetic metamaterial (MM) superlens on long-range near-field WPT, quantitatively confirming in simulation and measurement at 13-16 MHz the conditions under which the superlens can enhance power transfer efficiency compared to the lens-less free-space system.

Fluorescence spectroscopy for field surveillance of THM formation precursors to increase sustainable drinking water treatment for the water industry

NASA Astrophysics Data System (ADS)

Stutter, Marc; Cooper, Pat; Wyness, Adam; Allan, Richard; Weir, Paul; Frogbrook, Zoe; Haffey, Mark

2017-04-01

Our understanding of the composition and diversity of dissolved organic matter (DOM) in natural waters is improving rapidly with techniques such as fluorescence spectroscopy. For the water industry issues of the reaction of DOM and different processes used to reduce microbial contamination in water for public supply are a pressing concern. A range of processes can be used but the common disinfection by free chlorine can react with DOM to produce a group of substances referred to as disinfection by-products (DBPs) that have been linked to health concerns. Hence, management at water treatment works aims to remove DOM prior to the disinfection reaction or change the treatment method. Both are costly financially and in terms of process chemical, such as coagulents that work variably with different DOM forms. Hence, enabling methods of catchment management, which have long been associated with tackling other forms of pollution (e.g. N, P) through source-pathway-receptor concepts, are options for the water industry where catchment raw water source management is a possible sustainable addition to conventional treatment. This presentation looks at the requirements and ongoing work to inform source water management options using bench-top fluorescence excitation-emission spectroscopy and hand-held sensors to detect DBP precursors, namely trihalomethanes (THMs), in complex multi-source environments. We start by introducing the forms of DOM discernible in the fluorescence excitation-emission matrix, how these have been ascribed to different compounds by previous studies and what wavelengths are available for in-situ detection. We then discuss methodology issues for sample storage and standard materials. Then we draw on results from a national set of Scottish catchments and a small catchment study to evaluate relationships between THM compounds from standard assay and GC-MS detection against spectral DOM surrogates, including catchment hydrochemical and spatial data covariates. This is supported by laboratory batch work on potential synergistic interactions for THM formation in mixtures of DOM types from isolated humic substances and amino-acid compounds; where the latter can provide markers for anthropogenic pollution sources such as wastewater and farm effluents. Finally, we conclude on some of the potential for these techniques for catchment raw source water management. We present a circular-sustainability argument whereby the broad range of DOM combinations detectable by fluorescence techniques allows consideration of catchment C-source markers of potential THM formation resulting from disinfection and of the microbial contaminants necessitating the disinfection treatment.

Calibration of Hydrophone Stations: Lessons Learned from the Ascension Island Experiment

DTIC Science & Technology

2000-09-01

source based on the implosion of a glass sphere for future long-range calibrations. RESEARCH ACCOMPLISHED The J.C. Ross, an icebreaker class...waters around Ascension Island. The blow - ups show the track in the immediate vicinity of the three hydrophones and plots their nominal location. The...used has practical and cost-driven limitations. Small implosive sources such as lightbulbs have been used from ships as hydrophone calibration sources

Introducing "Emotioncy" as a Potential Source of Test Bias: A Mixed Rasch Modeling Study

ERIC Educational Resources Information Center

Pishghadam, Reza; Baghaei, Purya; Seyednozadi, Zahra

2017-01-01

This article attempts to present emotioncy as a potential source of test bias to inform the analysis of test item performance. Emotioncy is defined as a hierarchy, ranging from "exvolvement" (auditory, visual, and kinesthetic) to "involvement" (inner and arch), to emphasize the emotions evoked by the senses. This study…

Urban PM in Eastern Germany: Source apportionment and contributions from different spatial scales

NASA Astrophysics Data System (ADS)

van Pinxteren, D.; Fomba, K. W.; Mothes, F.; Spindler, G.; Herrmann, H.

2017-12-01

Understanding the contributions of particulate matter (PM) sources and the source areas impacting total PM levels in a city are important requirements for further developing clean air policies and efficient abatement strategies. This presentation reports on two studies in Eastern Germany providing a detailed picture of present-day urban PM sources and discriminating contributions of local, regional and long-range sources. The "Leipzig Aerosol 2013-15" study yielded contributions of 12 sources to coarse, fine, and ultrafine particles, resolved by Positive Matrix Factorization (PMF) from comprehensive chemical speciation of 5-stage Berner impactor samples at 4 different sites in the Leipzig area. Dominant winter-time sources were traffic exhaust and non-exhaust emissions, secondary aerosol formation, and combustion emissions from both biomass and coal burning with different relative importance in different particle size ranges. Local sources dominated PM levels in ultrafine and coarse particles (60% - 80%) while high mass concentrations in accumulation mode particles mainly resulted from regional import into the city (70%). The "PM-East" study compiled PM10 mass and constituents' concentrations at 10 urban and rural sites in Eastern Germany during winter 2016/17, which included a 3-week episode of frequent exceedances of the PM10 limit value. PMF source apportionment is performed for a subset of the sites, including the city of Berlin. Contributions from short-, mid-, and long-range sources, including trans-boundary pollution import from neighbouring countries, are quantitatively assessed by advanced back trajectory statistical methods. Data analysis in PM-East is ongoing and final results will be available by November. Funding is acknowledged from 4 federal states of Germany: Berlin Senate Department for Environment, Transport and Climate Protection; Saxon State Office for Environment, Agriculture and Geology; State Agency for Environment, Nature Conservation and Geology Mecklenburg-Vorpommern; and Brandenburg State Office for Environment.

Assessing the breeding potential of extra-long staple germplasm in an upland cotton breeding program

USDA-ARS?s Scientific Manuscript database

Fiber quality improvement of upland cotton (Gossypium hirsutum L.) is essential to increase the value and competitiveness of cotton fiber. The closely related allotetraploid species G. barbadense has long been targeted as a source of beneficial fiber quality alleles. Although interspecific hybridiza...

Source tagging modeling study of heavy haze episodes under complex regional transport processes over Wuhan megacity, Central China.

PubMed

Lu, Miaomiao; Tang, Xiao; Wang, Zifa; Gbaguidi, Alex; Liang, Shengwen; Hu, Ke; Wu, Lin; Wu, Huangjian; Huang, Zhen; Shen, Longjiao

2017-12-01

Wuhan as a megacity of Central China was suffering from severe particulate matter pollution according to previous observation studies, however, the mechanism behind the pollution formation especially the impact of regional chemical transport is still unclear. This study, carried out on the Nested Air Quality Prediction Modeling System (NAQPMS) coupled with an on-line source-tagging module, explores different roles regional transport had in two strong haze episodes over Wuhan in October 2014 and quantitatively assesses the contributions from local and regional sources to PM 2.5 concentration. Validation of predictions based on observations shows modeling system good skills in reproducing key meteorological and chemical features. The first short-time haze episode occurred on 12 October under strong northerly winds, with a hourly PM 2.5 peak of 180 μg m -3 , and was found to be caused primarily by the long-range transport from the northern regions, which contributed 60.6% of the episode's PM 2.5 concentration (versus a total of 32.7% from sources in and near Wuhan). The second episode lasted from the 15-20 October under stable regional large-scale synoptic conditions and weak winds, and had an hourly PM 2.5 peak of 231.0 μg m -3 . In this episode, both the long-distance transport from far regions and short-range transport from the Wuhan-cluster were the primary causes of the haze episode and account for 24.8% and 29.2% of the PM 2.5 concentration respectively. Therefore, regional transport acts as a crucial driver of haze pollution over Wuhan through not only long-range transfer of pollutants, but also short-range aerosol movement under specific meteorological conditions. The present findings highlight the important role of regional transport in urban haze formation and indicate that the joint control of multi city-clusters are needed to reduce the particulate pollution level in Wuhan. Copyright © 2017 Elsevier Ltd. All rights reserved.

A multiwave range test for obstacle reconstructions with unknown physical properties

NASA Astrophysics Data System (ADS)

Potthast, Roland; Schulz, Jochen

2007-08-01

We develop a new multiwave version of the range test for shape reconstruction in inverse scattering theory. The range test [R. Potthast, et al., A `range test' for determining scatterers with unknown physical properties, Inverse Problems 19(3) (2003) 533-547] has originally been proposed to obtain knowledge about an unknown scatterer when the far field pattern for only one plane wave is given. Here, we extend the method to the case of multiple waves and show that the full shape of the unknown scatterer can be reconstructed. We further will clarify the relation between the range test methods, the potential method [A. Kirsch, R. Kress, On an integral equation of the first kind in inverse acoustic scattering, in: Inverse Problems (Oberwolfach, 1986), Internationale Schriftenreihe zur Numerischen Mathematik, vol. 77, Birkhauser, Basel, 1986, pp. 93-102] and the singular sources method [R. Potthast, Point sources and multipoles in inverse scattering theory, Habilitation Thesis, Gottingen, 1999]. In particular, we propose a new version of the Kirsch-Kress method using the range test and a new approach to the singular sources method based on the range test and potential method. Numerical examples of reconstructions for all four methods are provided.

Mangiferin: A xanthonoid with multipotent anti-inflammatory potential.

PubMed

Saha, Sukanya; Sadhukhan, Pritam; Sil, Parames C

2016-09-10

Over the last era, small molecules sourced from different plants have gained attention for their varied and long-term medicinal benefits. Their advantageous therapeutic effects in diverse pathological complications lead researchers to give an ever-increasing emphasis on them and discover their novel therapeutic potentials. Among these, the heat stable, xanthonoid group of organic molecules has gained special importance with distinctive regards to the bioactive molecule mangiferin due to its solubility in water. Mangiferin, a yellow polyphenol having C-glycosyl xanthone structure, is widely present in different edible sources like mango, and possesses numerous biological activities. Extensive research with this molecule shows its antioxidant, anti-inflammatory, antidiabetic, anticancer, antimicrobial, analgesic, and immunomodulatory properties. Thus, it provides protection against a wide range of physiological disorders. The C-glucosyl linkage and polyhydroxy groups in mangiferin's structure contribute essentially to its free radical-scavenging activity. Moreover, its ability in regulating various transcription factors like NF-κB, Nrf-2, etc. and modulating the expression of different proinflammatory signaling intermediates like tumor necrosis factor-α, COX-2, etc. contribute to its anti-inflammatory, anticancer, and antidiabetic potentials. In this comprehensive article, information has been provided about the sources, chemical structure, metabolism, and different biological activities of mangiferin with special emphasis on the underlying cellular signal transduction pathways. Insights into an in-depth assessment of mangiferin's anti-inflammatory therapeutic potential have also been discussed in detail. On an overall perspective, this review aims to stage mangiferin's diversified therapeutic applications and its emerging possibility as a promising drug in future based on its anti-inflammatory property. © 2016 BioFactors, 42(5):459-474, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

Detecting and analyzing soil phosphorus loss associated with critical source areas using a remote sensing approach.

PubMed

Lou, Hezhen; Yang, Shengtian; Zhao, Changsen; Shi, Liuhua; Wu, Linna; Wang, Yue; Wang, Zhiwei

2016-12-15

The detection of critical source areas (CSAs) is a key step in managing soil phosphorus (P) loss and preventing the long-term eutrophication of water bodies at regional scale. Most related studies, however, focus on a local scale, which prevents a clear understanding of the spatial distribution of CSAs for soil P loss at regional scale. Moreover, the continual, long-term variation in CSAs was scarcely reported. It is impossible to identify the factors driving the variation in CSAs, or to collect land surface information essential for CSAs detection, by merely using the conventional methodologies at regional scale. This study proposes a new regional-scale approach, based on three satellite sensors (ASTER, TM/ETM and MODIS), that were implemented successfully to detect CSAs at regional scale over 15years (2000-2014). The approach incorporated five factors (precipitation, slope, soil erosion, land use, soil total phosphorus) that drive soil P loss from CSAs. Results show that the average area of critical phosphorus source areas (CPSAs) was 15,056km 2 over the 15-year period, and it occupied 13.8% of the total area, with a range varying from 1.2% to 23.0%, in a representative, intensive agricultural area of China. In contrast to previous studies, we found that the locations of CSAs with P loss are spatially variable, and are more dispersed in their distribution over the long term. We also found that precipitation acts as a key driving factor in the variation of CSAs at regional scale. The regional-scale method can provide scientific guidance for managing soil phosphorus loss and preventing the long-term eutrophication of water bodies at regional scale, and shows great potential for exploring factors that drive the variation in CSAs at global scale. Copyright © 2016 Elsevier B.V. All rights reserved.

Phenolic-enriched foods: sources and processing for enhanced health benefits.

PubMed

McDougall, Gordon J

2017-05-01

Polyphenols are ubiquitous secondary products present in many plant foods. Their intake has been associated with health benefits ranging from reduced incidence of CVD, diabetes and cancers to improved neurodegenerative outcomes. Major dietary sources include beverages such as coffee, teas and foods such as chocolate. Fruits are also major sources and berries in particular are a palatable source of a diverse range of polyphenol components. There are a number of ways that polyphenol uptake could be increased and healthier polyphenol-rich foods could be produced with specific compositions to target-specific health effects. Firstly, we could exploit the genetic diversity of plants (with a focus on berries) to select varieties that have enhanced levels of specific polyphenols implicated in disease mitigation (e.g. anthocyanins, tannins or flavonols). Working with variation induced by environmental and agronomic factors, modern molecular breeding techniques could exploit natural variation and beneficially alter polyphenol content and composition, although this could be relatively long term. Alternatively, we could employ a synthetic biology approach and design new plants that overexpress certain genes or re-deploy more metabolic effort into specific polyphenols. However, such 'polyphenol-plus' fruit could prove unpalatable as polyphenols contribute to sensorial properties (e.g. astringency of tannins). However, if the aim was to produce a polyphenol as a pharmaceutical then 'lifting' biosynthetic pathways from plants and expressing them in microbial vectors may be a feasible option. Secondly, we could design processing methods to enhance the polyphenolic composition or content of foods. Fermentation of teas, cocoa beans and grapes, or roasting of cocoa and coffee beans has long been used and can massively influence polyphenol composition and potential bioactivity. Simple methods such as milling, heat treatment, pasteurisation or juicing (v. pureeing) can have notable effects on polyphenol profiles and novel extraction methods bring new opportunities. Encapsulation methods can protect specific polyphenols during digestion and increase their delivery in the gastrointestinal tract to target-specific health effects. Lastly we could examine reformulation of products to alter polyphenol content or composition. Enhancing staple apple or citrus juices with berry juices could double polyphenol levels and provide specific polyphenol components. Reformulation of foods with polyphenol-rich factions recovered from 'wastes' could increase polyphenol intake, alter product acceptability, improve shelf life and prevent food spoilage. Finally, co-formulation of foods can influence bioavailability and potential bioactivity of certain polyphenols. Within the constraints that certain polyphenols can interfere with drug effectiveness through altered metabolism, this provides another avenue to enhance polyphenol intake and potential effectiveness. In conclusion, these approaches could be developed separately or in combination to produce foods with enhanced levels of phenolic components that are effective against specific disease conditions.

Research in Computational Astrobiology

NASA Technical Reports Server (NTRS)

Chaban, Galina; Jaffe, Richard; Liang, Shoudan; New, Michael H.; Pohorille, Andrew; Wilson, Michael A.

2002-01-01

We present results from several projects in the new field of computational astrobiology, which is devoted to advancing our understanding of the origin, evolution and distribution of life in the Universe using theoretical and computational tools. We have developed a procedure for calculating long-range effects in molecular dynamics using a plane wave expansion of the electrostatic potential. This method is expected to be highly efficient for simulating biological systems on massively parallel supercomputers. We have perform genomics analysis on a family of actin binding proteins. We have performed quantum mechanical calculations on carbon nanotubes and nucleic acids, which simulations will allow us to investigate possible sources of organic material on the early earth. Finally, we have developed a model of protobiological chemistry using neural networks.

Simultaneous distance measurement at multiple wavelengths using the intermode beats from a femtosecond laser coherent supercontinuum

NASA Astrophysics Data System (ADS)

Salido-Monzú, David; Wieser, Andreas

2018-04-01

The intermode beats generated by direct detection of a mode-locked femtosecond laser represent inherent high-quality and high-frequency modulations suitable for electro-optical distance measurement (EDM). This approach has already been demonstrated as a robust alternative to standard long-distance EDM techniques. However, we extend this idea to intermode beating of a wideband source obtained by spectral broadening of a femtosecond laser. We aim at establishing a technological basis for accurate and flexible multiwavelength distance measurement. Results are presented from experiments using beat notes at 1 GHz generated by two bandpass-filtered regions from both extremes of a coherent supercontinuum ranging from 550 to 1050 nm. The displacement measurements performed simultaneously on both colors on a short-distance setup show that noise and coherence of the wideband laser are adequate for achieving accuracies of about 0.01 mm on each channel with a potential improvement by accessing higher beat notes. Pointing and power instabilities have been identified as dominant sources of systematic deviations. Nevertheless, the results demonstrate the basic feasibility of the proposed technique. We consider this a promising starting point for the further development of multiwavelength EDM enabling increased accuracy over long distances through dispersion-based integral refractivity compensation and for remote surface material probing along with distance measurement in laser scanning.

The Weak Fe Fluorescence Line and Long-Term X-Ray Evolution of the Compton-Thick Active Galactic Nucleus in NGC7674

NASA Technical Reports Server (NTRS)

Ghandi, P.; Annuar, A.; Lansbury, G. B.; Stern, D.; Alexander, D. M.; Bauer, F. E.; Bianchi, S.; Boggs, S. E.; Boorman, P. G.; Brandt, W. N.;

The weak Fe fluorescence line and long-term X-ray evolution of the Compton-thick active galactic nucleus in NGC 7674

NASA Astrophysics Data System (ADS)

Gandhi, P.; Annuar, A.; Lansbury, G. B.; Stern, D.; Alexander, D. M.; Bauer, F. E.; Bianchi, S.; Boggs, S. E.; Boorman, P. G.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Del Moro, A.; Elvis, M.; Guainazzi, M.; Hailey, C. J.; Harrison, F. A.; Koss, M.; Lamperti, I.; Malaguti, G.; Masini, A.; Matt, G.; Puccetti, S.; Ricci, C.; Rivers, E.; Walton, D. J.; Zhang, W. W.

2017-06-01

We present NuSTAR X-ray observations of the active galactic nucleus (AGN) in NGC 7674. The source shows a flat X-ray spectrum, suggesting that it is obscured by Compton-thick gas columns. Based upon long-term flux dimming, previous work suggested the alternate possibility that the source is a recently switched-off AGN with the observed X-rays being the lagged echo from the torus. Our high-quality data show the source to be reflection-dominated in hard X-rays, but with a relatively weak neutral Fe Kα emission line (equivalent width [EW] of ≈ 0.4 keV) and a strong Fe xxvi ionized line (EW ≈ 0.2 keV). We construct an updated long-term X-ray light curve of NGC 7674 and find that the observed 2-10 keV flux has remained constant for the past ≈ 20 yr, following a high-flux state probed by Ginga. Light travel time arguments constrain the minimum radius of the reflector to be ˜ 3.2 pc under the switched-off AGN scenario, ≈ 30 times larger than the expected dust sublimation radius, rendering this possibility unlikely. A patchy Compton-thick AGN (CTAGN) solution is plausible, requiring a minimum line-of-sight column density (NH) of 3 × 1024 cm-2 at present, and yields an intrinsic 2-10 keV luminosity of (3-5) × 1043 erg s-1. Realistic uncertainties span the range of ≈ (1-13) × 1043 erg s-1. The source has one of the weakest fluorescence lines amongst bona fide CTAGN, and is potentially a local analogue of bolometrically luminous systems showing complex neutral and ionized Fe emission. It exemplifies the difficulty of identification and proper characterization of distant CTAGN based on the strength of the neutral Fe Kα line.

Density-dependent microbial turnover improves soil carbon model predictions of long-term litter manipulations

NASA Astrophysics Data System (ADS)

Georgiou, Katerina; Abramoff, Rose; Harte, John; Riley, William; Torn, Margaret

2017-04-01

Climatic, atmospheric, and land-use changes all have the potential to alter soil microbial activity via abiotic effects on soil or mediated by changes in plant inputs. Recently, many promising microbial models of soil organic carbon (SOC) decomposition have been proposed to advance understanding and prediction of climate and carbon (C) feedbacks. Most of these models, however, exhibit unrealistic oscillatory behavior and SOC insensitivity to long-term changes in C inputs. Here we diagnose the sources of instability in four models that span the range of complexity of these recent microbial models, by sequentially adding complexity to a simple model to include microbial physiology, a mineral sorption isotherm, and enzyme dynamics. We propose a formulation that introduces density-dependence of microbial turnover, which acts to limit population sizes and reduce oscillations. We compare these models to results from 24 long-term C-input field manipulations, including the Detritus Input and Removal Treatment (DIRT) experiments, to show that there are clear metrics that can be used to distinguish and validate the inherent dynamics of each model structure. We find that widely used first-order models and microbial models without density-dependence cannot readily capture the range of long-term responses observed across the DIRT experiments as a direct consequence of their model structures. The proposed formulation improves predictions of long-term C-input changes, and implies greater SOC storage associated with CO2-fertilization-driven increases in C inputs over the coming century compared to common microbial models. Finally, we discuss our findings in the context of improving microbial model behavior for inclusion in Earth System Models.

Tuning of successively scanned two monolithic Vernier-tuned lasers and selective data sampling in optical comb swept source optical coherence tomography

PubMed Central

Choi, Dong-hak; Yoshimura, Reiko; Ohbayashi, Kohji

2013-01-01

Monolithic Vernier tuned super-structure grating distributed Bragg reflector (SSG-DBR) lasers are expected to become one of the most promising sources for swept source optical coherence tomography (SS-OCT) with a long coherence length, reduced sensitivity roll-off, and potential capability for a very fast A-scan rate. However, previous implementations of the lasers suffer from four main problems: 1) frequencies deviate from the targeted values when scanned, 2) large amounts of noise appear associated with abrupt changes in injection currents, 3) optically aliased noise appears due to a long coherence length, and 4) the narrow wavelength coverage of a single chip limits resolution. We have developed a method of dynamical frequency tuning, a method of selective data sampling to eliminate current switching noise, an interferometer to reduce aliased noise, and an excess-noise-free connection of two serially scanned lasers to enhance resolution to solve these problems. An optical frequency comb SS-OCT system was achieved with a sensitivity of 124 dB and a dynamic range of 55-72 dB that depended on the depth at an A-scan rate of 3.1 kHz with a resolution of 15 μm by discretely scanning two SSG-DBR lasers, i.e., L-band (1.560-1.599 μm) and UL-band (1.598-1.640 μm). A few OCT images with excellent image penetration depth were obtained. PMID:24409394

Effective theory and breakdown of conformal symmetry in a long-range quantum chain

NASA Astrophysics Data System (ADS)

Lepori, L.; Vodola, D.; Pupillo, G.; Gori, G.; Trombettoni, A.

2016-11-01

We deal with the problem of studying the symmetries and the effective theories of long-range models around their critical points. A prominent issue is to determine whether they possess (or not) conformal symmetry (CS) at criticality and how the presence of CS depends on the range of the interactions. To have a model, both simple to treat and interesting, where to investigate these questions, we focus on the Kitaev chain with long-range pairings decaying with distance as power-law with exponent α. This is a quadratic solvable model, yet displaying non-trivial quantum phase transitions. Two critical lines are found, occurring respectively at a positive and a negative chemical potential. Focusing first on the critical line at positive chemical potential, by means of a renormalization group approach we derive its effective theory close to criticality. Our main result is that the effective action is the sum of two terms: a Dirac action SD, found in the short-range Ising universality class, and an "anomalous" CS breaking term SAN. While SD originates from low-energy excitations in the spectrum, SAN originates from the higher energy modes where singularities develop, due to the long-range nature of the model. At criticality SAN flows to zero for α > 2, while for α < 2 it dominates and determines the breakdown of the CS. Out of criticality SAN breaks, in the considered approximation, the effective Lorentz invariance (ELI) for every finite α. As α increases such ELI breakdown becomes less and less pronounced and in the short-range limit α → ∞ the ELI is restored. In order to test the validity of the determined effective theory, we compared the two-fermion static correlation functions and the von Neumann entropy obtained from them with the ones calculated on the lattice, finding agreement. These results explain two observed features characteristic of long-range models, the hybrid decay of static correlation functions within gapped phases and the area-law violation for the von Neumann entropy. The proposed scenario is expected to hold in other long-range models displaying quasiparticle excitations in ballistic regime. From the effective theory one can also see that new phases emerge for α < 1. Finally we show that at every finite α the critical exponents, defined as for the short-range (α → ∞) model, are not altered. This also shows that the long-range paired Kitaev chain provides an example of a long-range model in which the value of α where the CS is broken does not coincide with the value at which the critical exponents start to differ from the ones of the corresponding short-range model. At variance, for the second critical line, having negative chemical potential, only SAN (SD) is present for 1 < α < 2 (for α > 2). Close to this line, where the minimum of the spectrum coincides with the momentum where singularities develop, the critical exponents change where CS is broken.

Thermodynamic entanglement of magnonic condensates

NASA Astrophysics Data System (ADS)

Yuan, H. Y.; Yung, Man-Hong

2018-02-01

Over the past decade, significant progress has been achieved to create Bose-Einstein condensates (BECs) of magnetic excitations, i.e., magnons, at room temperature, which is a novel quantum many-body system with a strong spin-spin correlation, and contains potential applications in magnonic spintronics. For quantum information science, the magnonic condensates can become an attractive source of quantum entanglement, which plays a central role in most of the quantum information processing tasks. Here we theoretically study the entanglement properties of a magnon gas above and below the condensation temperature. We show that the thermodynamic entanglement of the spins is a manifestation of the off-diagonal long-range order; the entanglement of the condensate does not vanish, even if the spins are separated by an infinitely long distance, which is fundamentally distinct from the normal magnetic ordering below the Curie temperature. In addition, the phase-transition point occurs when the derivative of the entanglement changes abruptly. These results provide a theoretical foundation for a future investigation of the magnon BEC in terms of quantum entanglement.

Operational and theoretical temperature considerations in a Penning surface plasma source

NASA Astrophysics Data System (ADS)

Faircloth, D. C.; Lawrie, S. R.; Pereira Da Costa, H.; Dudnikov, V.

2015-04-01

A fully detailed 3D thermal model of the ISIS Penning surface plasma source is developed in ANSYS. The proportion of discharge power applied to the anode and cathode is varied until the simulation matches the operational temperature observations. The range of possible thermal contact resistances are modelled, which gives an estimation that between 67% and 85% of the discharge power goes to the cathode. Transient models show the electrode surface temperature rise during the discharge pulse for a range of duty cycles. The implications of these measurements are discussed and a mechanism for governing cesium coverage proposed. The requirements for the design of a high current long pulse source are stated.

Atmospheric Removal of Very Long-lived Greenhouse Gases in the Mesosphere

NASA Astrophysics Data System (ADS)

Totterdill, A.; Kovacs, T.; Gomez Martin, J.; FENG, W.; Chipperfield, M.; Plane, J. M.

2013-12-01

Chlorofluorocarbons are known to have serious ozone depleting and global warming potentials. Perfluorinated compounds such as SF6, NF3, SF5CF3 and CF3CF2Cl which have very long lifetimes (ranging from a few centuries to over 3000 years) are too stable to affect stratospheric ozone but do have among the highest per molecule radiative forcing of any greenhouse pollutant, making them extremely potent greenhouse gases. Due to the stability of these gases in the lower atmosphere, mesospheric loss processes could significantly reduce their estimated atmospheric lifetimes and hence, overall climate impact. Potential sinks include reactions with metals and energetic particles such as electrons or short wavelength photons already present in the upper atmosphere. The metals, in this instance iron, sodium or potassium, are produced by meteoric ablation, while background and energetic electrons have the continuous source of photoionization and auroral precipitation, respectively. In this study we investigate the removal potentials of four very long lived gases (SF6, NF3, SF5CF3 and CF3CF2Cl). First, by four metals (Fe, Mg, Na and K), where rate coefficients are measured using the Fast Flow Tube and Pulsed Laser Flash Photolysis / Laser Induced Fluorescence techniques. Second, removal by electron attachment was investigated using a quadrupole mass spectrometer. measurements. Third, Lyman-alpha (121.56 nm) photolysis was measured in a VUV absorption cell. The resulting removal rate coefficients are currently being input into the Whole Atmosphere Community Climate Model (WACCM) to obtain lifetime measurements for these species.

Investigation of Magnetotelluric Source Effect Based on Twenty Years of Telluric and Geomagnetic Observation

NASA Astrophysics Data System (ADS)

Kis, A.; Lemperger, I.; Wesztergom, V.; Menvielle, M.; Szalai, S.; Novák, A.; Hada, T.; Matsukiyo, S.; Lethy, A. M.

2016-12-01

Magnetotelluric method is widely applied for investigation of subsurface structures by imaging the spatial distribution of electric conductivity. The method is based on the experimental determination of surface electromagnetic impedance tensor (Z) by surface geomagnetic and telluric registrations in two perpendicular orientation. In practical explorations the accurate estimation of Z necessitates the application of robust statistical methods for two reasons:1) the geomagnetic and telluric time series' are contaminated by man-made noise components and2) the non-homogeneous behavior of ionospheric current systems in the period range of interest (ELF-ULF and longer periods) results in systematic deviation of the impedance of individual time windows.Robust statistics manage both load of Z for the purpose of subsurface investigations. However, accurate analysis of the long term temporal variation of the first and second statistical moments of Z may provide valuable information about the characteristics of the ionospheric source current systems. Temporal variation of extent, spatial variability and orientation of the ionospheric source currents has specific effects on the surface impedance tensor. Twenty year long geomagnetic and telluric recordings of the Nagycenk Geophysical Observatory provides unique opportunity to reconstruct the so called magnetotelluric source effect and obtain information about the spatial and temporal behavior of ionospheric source currents at mid-latitudes. Detailed investigation of time series of surface electromagnetic impedance tensor has been carried out in different frequency classes of the ULF range. The presentation aims to provide a brief review of our results related to long term periodic modulations, up to solar cycle scale and about eventual deviations of the electromagnetic impedance and so the reconstructed equivalent ionospheric source effects.

SP-100 multimegawatt scaleup to meet electric propulsion mission requirements

NASA Astrophysics Data System (ADS)

Newkirk, D. W.; Salamah, S. A.; Stewart, S. L.; Pluta, P. R.

The SP-100 nuclear heat source technology, utilizing uranium nitride fuel clad in PWC-11 in a fast reactor with lithium coolant circulated by an electromagnetic pump, is shown to be directly extrapolatable to thermal power levels that meet NASA nuclear electric propulsion requirements using different power conversion techniques. The SP-100 nuclear technology can be applied to missions with NEP (nuclear electric propulsion) requirements as low as tens of kWe to tens of MWe. It is pointed out that the SP-100 heat source has a great advantage of very long lifetime capability, since it utilizes very rugged refractory metal fuel pins and is independent of the power conversion scheme chosen for a given mission. The only moving parts in the nuclear subsystems are the control rods moved to compensate for fuel enrichment degradation due to fission and for power shutdown. Lowest alpha values in the range of interest for potential NASA missions are predicted for the dynamic Rankine and static HYTEC conversion systems.

[Tracing Sources of Sulfate Aerosol in Nanjing Northern Suburb Using Sulfur and Oxygen Isotopes].

PubMed

Wei, Ying; Guo, Zhao-bing; Ge, Xin; Zhu, Sheng-nan; Jiang, Wen-juan; Shi, Lei; Chen, Shu

2015-04-01

Abstract: To trace the sources of sulfate contributing to atmospheric aerosol, PM2.5 samples for isotopic analysis were collected in Nanjing northern suburb during January 2014. The sulfur and oxygen isotopic compositions of sulfate from these samples were determined by EA-IRMS. Source identification and apportionment were carried out using stable isotopic and chemical evidences, combined with absolute principal component analysis (APCA) method. The Δ34S values of aerosol sulfate ranged from 2.7 per thousand to 6.4 per thousand, with an average of 5.0 per thousand ± 0.9 per thousand, while the Δ18O values ranged from 10.6 per thousand to 16.1 per thousand, with an average of 12.5 per thousand ± 1.37 per thousand. In conjunction with air mass trajectories, the results suggested that aerosol sulfates were controlled by a dominance of local anthropogenic sulfate, followed by the contributions of long-distance transported sulfate. There was a minor effect of some other low-Δ34S valued sulfates, which might be expected from biogenic sources. Absolute principal component analysis results showed that the contributions of anthropogenic sulfate and long-distance transported sulfate were 46.74% and 31.54%, respectively.

Long distance quantum teleportation in a quantum relay configuration.

PubMed

de Riedmatten, H; Marcikic, I; Tittel, W; Zbinden, H; Collins, D; Gisin, N

2004-01-30

A long distance quantum teleportation experiment with a fiber-delayed Bell state measurement (BSM) is reported. The source creating the qubits to be teleported and the source creating the necessary entangled state are connected to the beam splitter realizing the BSM by two 2 km long optical fibers. In addition, the teleported qubits are analyzed after 2.2 km of optical fiber, in another laboratory separated by 55 m. Time-bin qubits carried by photons at 1310 nm are teleported onto photons at 1550 nm. The fidelity is of 77%, above the maximal value obtainable without entanglement. This is the first realization of an elementary quantum relay over significant distances, which will allow an increase in the range of quantum communication and quantum key distribution.

Management and Research Applications of Long-range Surveillance Radar Data for Birds, Bats, and Flying Insects

USGS Publications Warehouse

Ruth, Janet M.; Buler, Jeffrey J.; Diehl, Robert H.; Sojda, Richard S.

2008-01-01

There is renewed interest in using long-range surveillance radar as a biological research tool due to substantial improvements in the network of radars within the United States. Technical improvements, the digital nature of the radar data, and the availability of computing power and geographic information systems, enable a broad range of biological applications. This publication provides a summary of long-range surveillance radar technology and applications of these data to questions about movement patterns of birds and other flying wildlife. The intended audience is potential radar-data end users, including natural-resource management and regulatory agencies, conservation organizations, and industry. This summary includes a definition of long-range surveillance radar, descriptions of its strengths and weaknesses, information on applications of the data, cost, methods of calibration, and what end users need to do, and some key references and resources.

Photon Intermediate Direct Energy Conversion Using a Strontium-90 Beta Source

NASA Astrophysics Data System (ADS)

Schott, Robert J.

This thesis covers an examination of a need for a compact, long lived power source and a proof of concept for one such design. To begin, tests were done dealing with photovoltaics and their lifetime while undergoing radiation damage from the source of interest, Strontium-90 (Sr-90). After completing these tests a system was designed, built, and ultimately tested over a range of pressures in order to test if a Photon Intermediate Direct Energy Conversion (PIDEC) system would be potentially viable. In brief, the PIDEC system tested for this thesis used two excimer gasses, Argon and Xenon, to produce photons. These gasses were excited into excimer production using a 10 mCi Sr-90 source and held in place at pressures ranging from 10-6 to 2400 psi by a pressure vessel. Photons produced were guided towards a photovoltaic by a mirror chamber lined with high efficiency aluminum mirrors. Outside of the pressure vessel a picoammeter read the current off of the photovoltaic and sent the current to a computer for data processing. Of primary interest was how the current changed based on the amount of energy captured by the gas plenum which was related to the pressure of the system. The overall efficiency of this system was low due to a non-optimized waveguide, much of the beta energy being lost beyond the gas plenum, and other factors. However, the results were sufficient to show that the process was successfully completed and making a new system to optimize for these features is warranted.

Assessment of infrasound signals recorded on seismic stations and infrasound arrays in the western United States using ground truth sources

NASA Astrophysics Data System (ADS)

Park, Junghyun; Hayward, Chris; Stump, Brian W.

2018-06-01

Ground truth sources in Utah during 2003-2013 are used to assess the contribution of temporal atmospheric conditions to infrasound detection and the predictive capabilities of atmospheric models. Ground truth sources consist of 28 long duration static rocket motor burn tests and 28 impulsive rocket body demolitions. Automated infrasound detections from a hybrid of regional seismometers and infrasound arrays use a combination of short-term time average/long-term time average ratios and spectral analyses. These detections are grouped into station triads using a Delaunay triangulation network and then associated to estimate phase velocity and azimuth to filter signals associated with a particular source location. The resulting range and azimuth distribution from sources to detecting stations varies seasonally and is consistent with predictions based on seasonal atmospheric models. Impulsive signals from rocket body detonations are observed at greater distances (>700 km) than the extended duration signals generated by the rocket burn test (up to 600 km). Infrasound energy attenuation associated with the two source types is quantified as a function of range and azimuth from infrasound amplitude measurements. Ray-tracing results using Ground-to-Space atmospheric specifications are compared to these observations and illustrate the degree to which the time variations in characteristics of the observations can be predicted over a multiple year time period.

Laser diode stack beam shaping for efficient and compact long-range laser illuminator design

NASA Astrophysics Data System (ADS)

Lutz, Y.; Poyet, J. M.

2014-04-01

Laser diode stacks are interesting laser sources for active imaging illuminators. They allow the accumulation of large amounts of energy in multi-pulse mode, which is best suited for long-range image recording. Even when the laser diode stacks are equipped with fast-axis collimation (FAC) and slow-axis collimation (SAC) micro-lenses, their beam parameter products BPP are not compatible with direct use in highly efficient and compact illuminators. This is particularly true when narrow divergences are required such as for long-range applications. A solution to overcome these difficulties is to enhance the poor slow-axis BPP by virtually restacking the laser diode stack. We present a beam shaping and homogenization method that is low-cost and efficient and has low alignment sensitivity. After conducting simulations, we have realized and characterized the illuminator. A compact long-range laser illuminator has been set up with a divergence of 3.5×2.6 mrad and a global efficiency of 81%. Here, a projection lens with a clear aperture of 62 mm and a focal length of 571 mm was used.

Five ab initio potential energy and dipole moment surfaces for hydrated NaCl and NaF. I. Two-body interactions

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

Wang, Yimin, E-mail: yimin.wang@emory.edu; Bowman, Joel M., E-mail: jmbowma@emory.edu; Kamarchik, Eugene, E-mail: eugene.kamarchik@gmail.com

2016-03-21

We report full-dimensional, ab initio-based potentials and dipole moment surfaces for NaCl, NaF, Na{sup +}H{sub 2}O, F{sup −}H{sub 2}O, and Cl{sup −}H{sub 2}O. The NaCl and NaF potentials are diabatic ones that dissociate to ions. These are obtained using spline fits to CCSD(T)/aug-cc-pV5Z energies. In addition, non-linear least square fits using the Born-Mayer-Huggins potential are presented, providing accurate parameters based strictly on the current ab initio energies. The long-range behavior of the NaCl and NaF potentials is shown to go, as expected, accurately to the point-charge Coulomb interaction. The three ion-H{sub 2}O potentials are permutationally invariant fits to roughly 20 000more » coupled cluster CCSD(T) energies (awCVTZ basis for Na{sup +} and aVTZ basis for Cl{sup −} and F{sup −}), over a large range of distances and H{sub 2}O intramolecular configurations. These potentials are switched accurately in the long range to the analytical ion-dipole interactions, to improve computational efficiency. Dipole moment surfaces are fits to MP2 data; for the ion-ion cases, these are well described in the intermediate- and long-range by the simple point-charge expression. The performance of these new fits is examined by direct comparison to additional ab initio energies and dipole moments along various cuts. Equilibrium structures, harmonic frequencies, and electronic dissociation energies are also reported and compared to direct ab initio results. These indicate the high fidelity of the new PESs.« less

Graphene: A partially ordered non-periodic solid

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

Wei, Dongshan; Wang, Feng, E-mail: fengwang@uark.edu

2014-10-14

Molecular dynamics simulations were performed to study the structural features of graphene over a wide range of temperatures from 50 to 4000 K using the PPBE-G potential [D. Wei, Y. Song, and F. Wang, J. Chem. Phys. 134, 184704 (2011)]. This potential was developed by force matching the Perdew-Burke-Ernzerhof (PBE) exchange correlation functional and has been validated previously to provide accurate potential energy surface for graphene at temperatures as high as 3000 K. Simulations with the PPBE‑G potential are the best available approximation to a direct Car-Parrinello Molecular Dynamics study of graphene. One advantage of the PBE-G potential is to allowmore » large simulation boxes to be modeled efficiently so that properties showing strong finite size effects can be studied. Our simulation box contains more than 600 000 C atoms and is one of the largest graphene boxes ever modeled. With the PPBE-G potential, the thermal-expansion coefficient is negative up to 4000 K. With a large box and an accurate potential, the critical exponent for the scaling properties associated with the normal-normal and height-height correlation functions was confirmed to be 0.85. This exponent remains constant up to 4000 K suggesting graphene to be in the deeply cooled regime even close to the experimental melting temperature. The reduced peak heights in the radial distribution function of graphene show an inverse power law dependence to distance, which indicates that a macroscopic graphene sheet will lose long-range crystalline order as predicted by the Mermin-Wagner instability. Although graphene loses long-range translational order, it retains long range orientational order as indicated by its orientational correlation function; graphene is thus partially ordered but not periodic.« less

Assessment of potential oil and gas resources in source rocks of the Alaska North Slope, 2012

USGS Publications Warehouse

Houseknecht, David W.; Rouse, William A.; Garrity, Christopher P.; Whidden, Katherine J.; Dumoulin, Julie A.; Schenk, Christopher J.; Charpentier, Ronald R.; Cook, Troy A.; Gaswirth, Stephanie B.; Kirschbaum, Mark A.; Pollastro, Richard M.

2012-01-01

The U.S. Geological Survey estimated potential, technically recoverable oil and gas resources for source rocks of the Alaska North Slope. Estimates (95-percent to 5-percent probability) range from zero to 2 billion barrels of oil and from zero to nearly 80 trillion cubic feet of gas.

The occurrence of Ambrosia pollen in the atmosphere of Northwest Turkey: investigation of possible source regions

NASA Astrophysics Data System (ADS)

Celenk, Sevcan; Malyer, Hulusi

2017-08-01

Ambrosia pollen was first reported as an important allergen in North America at the end of the nineteenth century, and many European countries have recently reported its increasing significance for pollen allergy. The aims of this study were to determine whether the highly allergenic Ambrosia pollen recorded during the studied period could be the result of long-distance transport (LDT) and to identify the potential sources of Ambrosia pollen grains. The study investigates Ambrosia pollen episodes during the peak term of six yearly periods between 2010 and 2015 by examining source regions in Ambrosia pollen in Bursa, Turkey. A volumetric trap was used for collecting the pollen samples, and the back-trajectory model was used to identify a potential source of atmospheric Ambrosia pollen. The days when pollen levels exceeded 30 P m-3 were computed, and clusters were shown on the figures. The study indicates that the Ambrosia pollen grains recorded during the episode in Bursa were not produced by local sources but transported long distances from potential source regions around the Azov Sea in Russia and Ukraine, Black Sea region of Turkey, Romania, and Bulgaria. Note that atmospheric concentrations of Ambrosia pollen exceeded the clinical threshold during 28 days during the investigation period. Taking into consideration the high allergenicity of Ambrosia pollen, the present findings suggest that the number of ragweed-sensitized individuals might increase in the near future in the region.

Dpf Analyses Yield Fully Analytic Potentials for the B ^1Πu ``BARRIER'' States of {Rb}_2 and {Li}_2 and AN Improved Ground-State Well Depth for {Rb}_2

NASA Astrophysics Data System (ADS)

Slaughter, Kai; Dattani, Nikesh S.; Amiot, Claude S.; Ross, Amanda J.; Le Roy, Robert J.

2015-06-01

Determining full model potential energy functions for molecular states that have a `natural' rotationless barrier which protrudes above the potential asymptote, such as the B ^1Π_u states of alkali dimers, is a challenging problem. The present work extends our previous Direct-Potential-Fit (DPF) analysis of data for the B ^1Π_u state of Li_2 by introducing a more sophisticated model for the long-range tail of the fully analytic `Double Exponential Long-Range' (DELR) potential function form^a that takes account of the interstate coupling that occurs near the asymptotes of nS+nP alkali dimers. This type of analysis is then applied to data for the B ^1Π_u state of Rb_2, and a concurrent extension of the DPF analysis of Seto and Le Roy yields an improved fully analytic potential energy function for its ground X ^1σ_g^+ state. The effect of taking account of the long-range inter-state coupling on the shapes of the outer walls of the B ^1Π_u state potential functions for these two species will also be examined. Y. Huang and R.J. Le Roy, J. Chem. Phys., 119, 7398 (2003) M. Aubert-Frécon and G. Hadinger and S. Magnier and S. Rousseau, J. Mol. Spectosc., 288, 182 (1998). J.Y. Seto and R.J. Le Roy, J. Chem. Phys., 113, 3067 (2000).

The MIT/OSO 7 catalog of X-ray sources - Intensities, spectra, and long-term variability

NASA Technical Reports Server (NTRS)

Markert, T. H.; Laird, F. N.; Clark, G. W.; Hearn, D. R.; Sprott, G. F.; Li, F. K.; Bradt, H. V.; Lewin, W. H. G.; Schnopper, H. W.; Winkler, P. F.

1979-01-01

This paper is a summary of the observations of the cosmic X-ray sky performed by the MIT 1-40-keV X-ray detectors on OSO 7 between October 1971 and May 1973. Specifically, mean intensities or upper limits of all third Uhuru or OSO 7 cataloged sources (185 sources) in the 3-10-keV range are computed. For those sources for which a statistically significant (greater than 20) intensity was found in the 3-10-keV band (138 sources), further intensity determinations were made in the 1-15-keV, 1-6-keV, and 15-40-keV energy bands. Graphs and other simple techniques are provided to aid the user in converting the observed counting rates to convenient units and in determining spectral parameters. Long-term light curves (counting rates in one or more energy bands as a function of time) are plotted for 86 of the brighter sources.

Legal and financial methods for reducing low emission sources: Options for incentives

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

Samitowski, W.

1995-12-31

There are two types of the so-called low emission sources in Cracow: over 1,000 local boiler houses and several thousand solid fuel-fired stoves. The accomplishment of each of 5 sub-projects offered under the American-Polish program entails solving the technical, financial, legal and public relations-related problems. The elimination of the low emission source requires, therefore, a joint effort of the following pairs: (a) local authorities, (b) investors, (c) owners and users of low emission sources, and (d) inhabitants involved in particular projects. The results of the studies developed by POLINVEST indicate that the accomplishment of the projects for the elimination ofmore » low emission sources will require financial incentives. Bearing in mind the today`s resources available from the community budget, this process may last as long as a dozen or so years. The task of the authorities of Cracow City is making a long-range operational strategy enabling reduction of low emission sources in Cracow.« less

Proposed modification of the criterion for the region of validity of the inverse-power expansion in diatomic long-range potentials

NASA Astrophysics Data System (ADS)

Ji, Bing; Tsai, Chin-Chun; Stwalley, William C.

1995-04-01

A modified internuclear distance criterion, RLR- m, as the lower bound for the region of validity of the inverse-power expansion of the diatomic long-range potential is proposed. This new criterion takes into account the spatial orientation of the atomic orbitals while retaining the simplicity of the traditional Le Roy radius, RLR for the interaction of S state atoms. Recent experimental and theoretical results for various excited states in Na 2 suggest that this proposed RLR- m is an appropriate generalization of RLR.

Cell-veto Monte Carlo algorithm for long-range systems.

PubMed

Kapfer, Sebastian C; Krauth, Werner

2016-09-01

We present a rigorous efficient event-chain Monte Carlo algorithm for long-range interacting particle systems. Using a cell-veto scheme within the factorized Metropolis algorithm, we compute each single-particle move with a fixed number of operations. For slowly decaying potentials such as Coulomb interactions, screening line charges allow us to take into account periodic boundary conditions. We discuss the performance of the cell-veto Monte Carlo algorithm for general inverse-power-law potentials, and illustrate how it provides a new outlook on one of the prominent bottlenecks in large-scale atomistic Monte Carlo simulations.

Characteristics of air quality and sources affecting fine particulate matter (PM2.5) levels in the City of Red Deer, Canada.

PubMed

Bari, Md Aynul; Kindzierski, Warren B

2017-02-01

With concern about levels and exceedances of Canadian and provincial standards and objectives for fine particulate matter (PM 2.5 ) in recent years, an investigation of air quality characteristics and potential local and long-range sources influencing PM 2.5 concentrations was undertaken in the City of Red Deer, Alberta. The study covered the period May 2009 to December 2015. Comparatively higher concentrations of PM 2.5 were observed in winter (mean: 11.6 μg/m 3 , median: 10 μg/m 3 ) than in summer (mean: 9.0 μg/m 3 , median: 7.0 μg/m 3 ). Exceedances of the 1 h Alberta Ambient Air Quality objective (3-31 times per year > 80 μg/m 3 ) and the 24 h Canada-Wide Standard (2-11 times per year > 30 μg/m 3 ) were found at the Red Deer Riverside air monitoring station, particularly in 2010, 2011 and 2015. Positive matrix factorization (PMF) followed by multiple linear regression (MLR) analysis identified a mixed industry/agriculture factor as the dominant contributor to PM 2.5 (39.3%), followed by an O 3 -rich (biogenic) factor (26.4%), traffic (19.3%), biomass burning (10.5%) and a mixed urban factor (4.4%). In addition to local traffic, the mixed industry/agriculture factor - inferred as mostly upstream oil and gas emission sources surrounding Red Deer - was identified as another potentially important source contributing to wintertime high PM 2.5 pollution days. These findings offer useful preliminary information about current PM 2.5 sources and their potential contributions in Red Deer; and this information can support policy makers in the development of particulate matter control strategies if required. Copyright © 2016 Elsevier Ltd. All rights reserved.

Temporal trends of Persistent Organic Pollutants (POPs) in arctic air: 20 years of monitoring under the Arctic Monitoring and Assessment Programme (AMAP).

PubMed

Hung, Hayley; Katsoyiannis, Athanasios A; Brorström-Lundén, Eva; Olafsdottir, Kristin; Aas, Wenche; Breivik, Knut; Bohlin-Nizzetto, Pernilla; Sigurdsson, Arni; Hakola, Hannele; Bossi, Rossana; Skov, Henrik; Sverko, Ed; Barresi, Enzo; Fellin, Phil; Wilson, Simon

2016-10-01

Temporal trends of Persistent Organic Pollutants (POPs) measured in Arctic air are essential in understanding long-range transport to remote regions and to evaluate the effectiveness of national and international chemical control initiatives, such as the Stockholm Convention (SC) on POPs. Long-term air monitoring of POPs is conducted under the Arctic Monitoring and Assessment Programme (AMAP) at four Arctic stations: Alert, Canada; Stórhöfði, Iceland; Zeppelin, Svalbard; and Pallas, Finland, since the 1990s using high volume air samplers. Temporal trends observed for POPs in Arctic air are summarized in this study. Most POPs listed for control under the SC, e.g. polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs) and chlordanes, are declining slowly in Arctic air, reflecting the reduction of primary emissions during the last two decades and increasing importance of secondary emissions. Slow declining trends also signifies their persistence and slow degradation under the Arctic environment, such that they are still detectable after being banned for decades in many countries. Some POPs, e.g. hexachlorobenzene (HCB) and lighter PCBs, showed increasing trends at specific locations, which may be attributable to warming in the region and continued primary emissions at source. Polybrominated diphenyl ethers (PBDEs) do not decline in air at Canada's Alert station but are declining in European Arctic air, which may be due to influence of local sources at Alert and the much higher historical usage of PBDEs in North America. Arctic air samples are screened for chemicals of emerging concern to provide information regarding their environmental persistence (P) and long-range transport potential (LRTP), which are important criteria for classification as a POP under SC. The AMAP network provides consistent and comparable air monitoring data of POPs for trend development and acts as a bridge between national monitoring programs and SC's Global Monitoring Plan (GMP). Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

ADAPTATION OF THE ADVANCED STATISTICAL TRAJECTORY REGIONAL AIR POLLUTION (ASTRAP) MODEL TO THE EPA VAX COMPUTER - MODIFICATIONS AND TESTING

EPA Science Inventory

The Advanced Statistical Trajectory Regional Air Pollution (ASTRAP) model simulates long-term transport and deposition of oxides of and nitrogen. t is a potential screening tool for assessing long-term effects on regional visibility from sulfur emission sources. owever, a rigorou...

Long-term effects of biosolid-amended soils on phosphorus, copper, manganese and zinc uptake by wheat

USDA-ARS?s Scientific Manuscript database

Biosolids have been applied to agricultural land for many years as a source of plant nutrients. There are growing concerns of residual phosphorus and metals from long-term biosolids amended fields and their potential impact on the environment. Objectives of this study were to determine, i) phosphor...

Long-ranged contributions to solvation free energies from theory and short-ranged models

PubMed Central

Remsing, Richard C.; Liu, Shule; Weeks, John D.

2016-01-01

Long-standing problems associated with long-ranged electrostatic interactions have plagued theory and simulation alike. Traditional lattice sum (Ewald-like) treatments of Coulomb interactions add significant overhead to computer simulations and can produce artifacts from spurious interactions between simulation cell images. These subtle issues become particularly apparent when estimating thermodynamic quantities, such as free energies of solvation in charged and polar systems, to which long-ranged Coulomb interactions typically make a large contribution. In this paper, we develop a framework for determining very accurate solvation free energies of systems with long-ranged interactions from models that interact with purely short-ranged potentials. Our approach is generally applicable and can be combined with existing computational and theoretical techniques for estimating solvation thermodynamics. We demonstrate the utility of our approach by examining the hydration thermodynamics of hydrophobic and ionic solutes and the solvation of a large, highly charged colloid that exhibits overcharging, a complex nonlinear electrostatic phenomenon whereby counterions from the solvent effectively overscreen and locally invert the integrated charge of the solvated object. PMID:26929375

Temporal distribution and potential sources of atmospheric mercury measured at a high-elevation background station in Taiwan

NASA Astrophysics Data System (ADS)

Sheu, Guey-Rong; Lin, Neng-Huei; Wang, Jia-Lin; Lee, Chung-Te; Ou Yang, Chang-Feng; Wang, Sheng-Hsiang

2010-07-01

Measurements of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM), and particulate mercury (PHg) have been conducted at Lulin Atmospheric Background Station (LABS) in Taiwan since April 2006. This was the first long-term free tropospheric atmospheric Hg monitoring program in the downwind region of East Asia, which is a major Hg emission source region. Between April 13, 2006 and December 31, 2007, the mean concentrations of GEM, RGM, and PHg were 1.73 ng m -3, 12.1 pg m -3, and 2.3 pg m -3, respectively. A diurnal pattern was observed for GEM with afternoon peaks and nighttime lows, whereas the diurnal pattern of RGM was opposite to that of GEM. Spikes of RGM were frequently observed between midnight and early morning with concurrent decreases in GEM and relative humidity and increases in O 3, suggesting the oxidation of GEM and formation of RGM in free troposphere (FT). Upslope movement of boundary layer (BL) air in daytime and subsidence of FT air at night resulted in these diurnal patterns. Considering only the nighttime data, which were more representative of FT air, the composite monthly mean GEM concentrations ranged between 1.06 and 2.06 ng m -3. Seasonal variation in nighttime GEM was evident, with lower concentrations usually occurring in summer when clean marine air masses prevailed. Between fall and spring, air masses passed the East Asian continent prior to reaching LABS, contributing to the elevated GEM concentrations. Analysis of GEM/CO correlation tends to support the argument. Good GEM/CO correlations were observed in fall, winter, and spring, suggesting influence of anthropogenic emission sources. Our results demonstrate the significance of East Asian Hg emissions, including both anthropogenic and biomass burning emissions, and their long-range transport in the FT. Because of the pronounced seasonal monsoon activity and the seasonal variation in regional wind field, export of the Asian Hg emissions to Taiwan occurs mainly during fall, winter, and spring.

The physico-chemical evolution of atmospheric aerosols and the gas-particle partitioning of inorganic aerosol during KORUS-AQ

NASA Astrophysics Data System (ADS)

Lee, T.; Park, T.; Lee, J. B.; Lim, Y. J.; Ahn, J.; Park, J. S.; Soo, C. J.; Desyaterik, Y.; Collett, J. L., Jr.

2017-12-01

Aerosols influence climate change directly by scattering and absorption and indirectly by acting as cloud condensation nuclei and some of the effects of aerosols are reduction in visibility, deterioration of human health, and deposition of pollutants to ecosystems. Urban area is large source of aerosols and aerosol precursors. Aerosol sources are both local and from long-range transport. Long-range transport processed aerosol are often dominant sources of aerosol pollution in Korea. To improve our knowledge of aerosol chemistry, Korea and U.S-Air Quality (KORUS-AQ) of Aircraft-based aerosol measurement took place in and around Seoul, Korea during May and June 2016. KORUS-AQ campaigns were conducted to study the chemical characterization and processes of pollutants in the Seoul Metropolitan area to regional scales of Korean peninsula. Aerodyne High Resolution Time of Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed on aircraft platforms on-board DC-8 (NASA) aircraft. We characterized aerosol chemical properties and mass concentrations of sulfate, nitrate, ammonium and organics in polluted air plumes and investigate the spatial and vertical distribution of the species. The results of studies show that organics is predominant in Aerosol and a significant fraction of the organics is oxygenated organic aerosol (OOA) at the high altitude. Both Nitrate and sulfate can partition between the gas and particle phases. The ratios for HNO3/(N(V) (=gaseous HNO3 + particulate Nitrate) and SO2/(SO2+Sulfate) were found to exhibit quite different distributions between the particles and gas phase for the locations during KORUS-AQ campaign, representing potential for formation of additional particulate nitrate and sulfate. The results of those studies can provide highly resolved temporal and spatial air pollutant, which are valuable for air quality model input parameters for aerosol behaviour.

Dissolved iron anomaly in the deep tropical-subtropical Pacific: Evidence for long-range transport of hydrothermal iron

NASA Astrophysics Data System (ADS)

Wu, Jingfeng; Wells, Mark L.; Rember, Robert

2011-01-01

Dissolved iron profiles along a north-south transect along 158°W in the tropical Pacific show evidence of two deepwater anomalies. The first extends from Station ALOHA (22.78°N) to the equator at ˜1000-1500 m and lies below the maximum apparent oxygen utilization and nutrient (N, P) concentrations. The feature is not supported by vertical export processes, but instead corresponds with the lateral dilution field of δ 3He derived from the Loihi seamount, Hawaii, though a sediment source associated with the Hawaiian Island Chain cannot be entirely ruled out. The second, deeper (2000-3000 m) anomaly occurs in tropical South Pacific waters (7°S) and also does not correlate with the depths of maximum nutrient concentrations or apparent oxygen utilization, but it does coincide closely with δ 3He emanating from the East Pacific Rise, more than 5000 km to the east. We hypothesize that these anomalies represent the long-range (>2000 km) transport of hydrothermal iron residuals, stabilized against scavenging by complexation with excess organic ligands in the plume source regions. Such trace leakage of hydrothermal iron to distal plume regions would have been difficult to identify in most hydrothermal vent mapping studies because low analytical detection limits were not needed for the proximal plume regions. These findings suggest that hydrothermal activity may represent a major source of dissolved iron throughout the South Pacific deep basin today, as well as other regions having high mid-ocean spreading rates in the geologic past. In particular, we hypothesize that high spreading rates along the South Atlantic and Southern Ocean mid-oceanic ridges, combined with the upwelling ventilation of these distal hydrothermal plumes, may have increased ocean productivity and carbon export in the Southern Ocean. Assessing the magnitude and persistence of dissolved hydrothermal iron in basin scale deep waters will be important for understanding the marine biogeochemistry of iron and, potentially, on ocean productivity and climate change during the geologic past.

Subsurface occurrence and potential source areas of chlorinated ethenes identified using concentrations and concentration ratios, Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

USGS Publications Warehouse

Garcia, C. Amanda

2005-01-01

The U.S. Geological Survey, in cooperation with the U.S. Air Force Aeronautical Systems Center, Environmental Management Directorate, conducted a study during 2003-05 to characterize the subsurface occurrence and identify potential source areas of the volatile organic compounds classified as chlorinated ethenes at U.S. Air Force Plant 4 (AFP4) and adjacent Naval Air Station-Joint Reserve Base Carswell Field (NAS-JRB) at Fort Worth, Texas. The solubilized chlorinated ethenes detected in the alluvial aquifer originated as either released solvents (tetrachloroethene [PCE], trichloroethene [TCE], and trans-1,2-dichloroethene [trans-DCE]) or degradation products of the released solvents (TCE, cis-1,2-dichloroethene [cis-DCE], and trans-DCE). The combined influences of topographic- and bedrock-surface configurations result in a water table that generally slopes away from a ground-water divide approximately coincident with bedrock highs and the 1-mile-long aircraft assembly building at AFP4. Highest TCE concentrations (10,000 to 920,000 micrograms per liter) occur near Building 181, west of Building 12, and at landfill 3. Highest PCE concentrations (500 to 920 micrograms per liter) occur near Buildings 4 and 5. Highest cis-DCE concentrations (5,000 to 710,000 micrograms per liter) occur at landfill 3. Highest trans-DCE concentrations (1,000 to 1,700 micrograms per liter) occur just south of Building 181 and at landfill 3. Ratios of parent-compound to daughter-product concentrations that increase in relatively short distances (tens to 100s of feet) along downgradient ground-water flow paths can indicate a contributing source in the vicinity of the increase. Largest increases in ratio of PCE to TCE concentrations are three orders of magnitude from 0.01 to 2.7 and 7.1 between nearby wells in the northeastern part of NAS-JRB. In the northern part of NAS-JRB, the largest increases in TCE to total DCE concentration ratios relative to ratios at upgradient wells are from 17 to 240 or from 17 to 260. In the southern part of NAS-JRB, the largest ratio increases with respect to those at upgradient wells are from 22 and 24 to 130, and from 0 and 7.2 to 71. Numerous maximum historical ratios of trans-DCE to cis-DCE are greater than 1, which can indicate that trans-DCE likely was released as a solvent and does not occur only as a result of degradation of TCE. High concentrations of TCE, PCE, cis-DCE, and trans-DCE, abrupt increases in ratios of PCE to TCE and TCE to total DCE, and ratios of trans-DCE to cis-DCE greater than 1 were used to identify 16 potential source areas of chlorinated ethenes at NAS-JRB. The evidence for some of the potential source areas is stronger than for others, but each area reflects one or more of the conditions indicative of chlorinated ethenes entering the aquifer. Potential source areas supported by the strongest evidence are Building 181, between buildings 4 and 5, just west of Building 12, and landfills 1 and 3. The highest historical TCE concentration in the study area, 920,000 micrograms per liter, is near Building 181. The potential source area between Buildings 4 and 5 primarily is identified by notably high PCE concentrations (to 920 micrograms per liter). Primary evidence for the potential source are just west of Building 12 is the notably high TCE concentrations (for example, 160,000 micrograms per liter) that appear to originate in the area. Primary evidence for the potential source area at landfills 1 and (primarily) 3 is the magnitudes of TCE concentrations (for example, two in the 100,000-to-920,000-microgram-per-liter range), cis-DCE concentrations (several in the 5,000-to-710,000-microgram-per-liter range), and trans-DCE concentrations (several in the 500-to-1,700-microgram-per-liter range). The ratio of trans-DCE to cis-DCE at one well in landfill 3 (6.7) is appreciably above the threshold that can indicate likely solvent release as opposed to TCE degradation alone.

REMEDIATION FLUID RECYCLING - APPLICATION OF PERVAPORATION TECHNOLOGY TO MATERIAL RECOVERY AND REUSE

EPA Science Inventory

In an effort to aggressively remove NAPL source areas, agents such as surfactants and alcohols have been added to in situ flusing systems to enhance the solubility of the NAPL components. Such an approach has the potential to reduce the risk posed by a long term source of ground...

REMEDIATION FLUID RECYCLING: APPLICATION OF PERVAPORATION TECHNOLOGY TO MATERIAL RECOVERY AND REUSE

EPA Science Inventory

In an effort to aggressively remove NAPL source areas, agents such as surfactants and alcohols have been added to in situ flushing systems to enhance the solubility of the NAPL components. Such an approach has the potential to reduce the risk posed by a long term source of groun...

REMEDIATION FLUID RECYCLING - APPLICATION OF PERVAPORATION TECHNOLOGY TO MATERIAL RECOVERY AND REUSEI

EPA Science Inventory

In an effort to aggressively remove NAPL source areas, agents such as surfactants and alcohols have been added to in situ flusing systems to enhance the solubility of the NAPL components. Such an approach has the potential to reduce the risk posed by a long term source of ground...

Source apportionments of PM2.5 organic carbon during the elevated pollution episodes in the Ordos region, Inner Mongolia, China.

PubMed

Khuzestani, Reza Bashiri; Schauer, James J; Shang, Jing; Cai, Tianqi; Fang, Dongqing; Wei, Yongjie; Zhang, Lulu; Zhang, Yuanxun

2018-05-01

The Ordos region in the southwestern part of Inner Mongolia experiences frequent PM concentrations in excess of the national PM 2.5 air quality standards. In order to determine the key sources of PM 2.5 contributing to these pollution episodes, the main sources of PM 2.5 OC during elevated PM episodes in the Inner Mongolia were analyzed and compared with non-polluted days. This will provide insight to the main sources of particulate matter pollution during the high-pollution episodes and the effective seasonal strategies to control sources of particulate matter during months and with the highest PM concentrations that need to be controlled. The PMF source contributions to OC demonstrated that the industrial/coal combustion (4762.77 ± 1061.54 versus 2726.49 ± 469.75 ng/m 3 ; p < 0.001) and mobile source factors (4651.14 ± 681.82 versus 2605.55 ± 276.50 ng/m 3 ; p value < 0.001) showed greater contributions to the elevated concentrations during the episode. The spatial analysis of secondary organic carbon (SOC) factors, regional biomass burning, and biogenic sources did not show significant difference in the pollution episodes and the non-polluted months. In addition, the bivariate polar plots and CWT maps of the industrial/coal combustion and mobile illustrated a regional long-range transport patterns from the external sources to the study area, however, adjacent areas were mostly controlling the contributions of these factors during the PM elevated episodes. The SOC sources, regional biomass burning, and biogenic sources illustrated a regional long-range transport with similar locations found during the elevated pollution episodes compared to the normal situations.

Long-pulse power-supply system for EAST neutral-beam injectors

NASA Astrophysics Data System (ADS)

Liu, Zhimin; Jiang, Caichao; Pan, Junjun; Liu, Sheng; Xu, Yongjian; Chen, Shiyong; Hu, Chundong; NBI Team

2017-05-01

The long-pulse power-supply system equipped for the 4 MW beam-power ion source is comprised of three units at ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences): one for the neutral-beam test stand and two for the EAST neutral-beam injectors (NBI-1 and NBI-2, respectively). Each power supply system consists of two low voltage and high current DC power supplies for plasma generation of the ion source, and two high voltage and high current DC power supplies for the accelerator grid system. The operation range of the NB power supply is about 80 percent of the design value, which is the safe and stable operation range. At the neutral-beam test stand, a hydrogen ion beam with a beam pulse of 150 s, beam power of 1.5 MW and beam energy of 50 keV was achieved during the long-pulse testing experiments. The result shows that the power-supply system meets the requirements of the EAST-NBIs fully and lays a basis for achieving plasma heating.

Low-Dose, Long-Wave UV Light Does Not Affect Gene Expression of Human Mesenchymal Stem Cells

PubMed Central

Wong, Darice Y.; Ranganath, Thanmayi; Kasko, Andrea M.

2015-01-01

Light is a non-invasive tool that is widely used in a range of biomedical applications. Techniques such as photopolymerization, photodegradation, and photouncaging can be used to alter the chemical and physical properties of biomaterials in the presence of live cells. Long-wave UV light (315 nm–400 nm) is an easily accessible and commonly used energy source for triggering biomaterial changes. Although exposure to low doses of long-wave UV light is generally accepted as biocompatible, most studies employing this wavelength only establish cell viability, ignoring other possible (non-toxic) effects. Since light exposure of wavelengths longer than 315 nm may potentially induce changes in cell behavior, we examined changes in gene expression of human mesenchymal stem cells exposed to light under both 2D and 3D culture conditions, including two different hydrogel fabrication techniques, decoupling UV exposure and radical generation. While exposure to long-wave UV light did not induce significant changes in gene expression regardless of culture conditions, significant changes were observed due to scaffold fabrication chemistry and between cells plated in 2D versus encapsulated in 3D scaffolds. In order to facilitate others in searching for more specific changes between the many conditions, the full data set is available on Gene Expression Omnibus for querying. PMID:26418040

Understanding and Utilizing Waveguide Invariant Range-frequency Striations in Ocean Acoustic Waveguides

DTIC Science & Technology

2011-02-01

Acoustical Society of America, 103(6):3234–3240, 1998 . 168 [55] Kathleen M. Stafford , Christopher G. Fox, and David S. Clark. Long - range acoustic detection ...and localization of blue whale calls in the northeast pacif c ocean. The Journal of the Acoustical Society of America, 104(6):3616–3625, 1998 . [56... range to the acoustic source assuming β = 1. Thode demonstrates this experimentally for shallow water with a Blue

Application of multimedia models for screening assessment of long-range transport potential and overall persistence.

PubMed

Klasmeier, Jörg; Matthies, Michael; Macleod, Matthew; Fenner, Kathrin; Scheringer, Martin; Stroebe, Maximilian; Le Gall, Anne Christine; Mckone, Thomas; Van De Meent, Dik; Wania, Frank

2006-01-01

We propose a multimedia model-based methodology to evaluate whether a chemical substance qualifies as POP-like based on overall persistence (Pov) and potential for long-range transport (LRTP). It relies upon screening chemicals against the Pov and LRTP characteristics of selected reference chemicals with well-established environmental fates. Results indicate that chemicals of high and low concern in terms of persistence and long-range transport can be consistently identified by eight contemporary multimedia models using the proposed methodology. Model results for three hypothetical chemicals illustrate that the model-based classification of chemicals according to Pov and LRTP is not always consistent with the single-media half-life approach proposed by the UNEP Stockholm Convention and thatthe models provide additional insight into the likely long-term hazards associated with chemicals in the environment. We suggest this model-based classification method be adopted as a complement to screening against defined half-life criteria at the initial stages of tiered assessments designed to identify POP-like chemicals and to prioritize further environmental fate studies for new and existing chemicals.

Renewable Energy Opportunities at White Sands Missile Range, New Mexico

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

Chvala, William D.; Solana, Amy E.; States, Jennifer C.

2008-09-01

The document provides an overview of renewable resource potential at White Sands Missile Range (WSMR) based primarily upon analysis of secondary data sources supplemented with limited on-site evaluations. The effort was funded by the U.S. Army Installation Management Command (IMCOM) as follow-on to the 2005 DoD Renewable Energy Assessment. This effort focuses on grid-connected generation of electricity from renewable energy sources and also ground source heat pumps (GSHPs) for heating and cooling buildings, as directed by IMCOM.

Source Mechanisms of Destructive Tsunamigenic Earthquakes occurred along the Major Subduction Zones

NASA Astrophysics Data System (ADS)

Yolsal-Çevikbilen, Seda; Taymaz, Tuncay; Ulutaş, Ergin

2016-04-01

Subduction zones, where an oceanic plate is subducted down into the mantle by tectonic forces, are potential tsunami locations. Many big, destructive and tsunamigenic earthquakes (Mw > 7.5) and high amplitude tsunami waves are observed along the major subduction zones particularly near Indonesia, Japan, Kuril and Aleutan Islands, Gulf of Alaska, Southern America. Not all earthquakes are tsunamigenic; in order to generate a tsunami, the earthquake must occur under or near the ocean, be large, and create significant vertical movements of the seafloor. It is also known that tsunamigenic earthquakes release their energy over a couple of minutes, have long source time functions and slow-smooth ruptures. In this study, we performed point-source inversions by using teleseismic long-period P- and SH- and broad-band P-waveforms recorded by the Federation of Digital Seismograph Networks (FDSN) and the Global Digital Seismograph Network (GDSN) stations. We obtained source mechanism parameters and finite-fault slip distributions of recent destructive ten earthquakes (Mw ≥ 7.5) by comparing the shapes and amplitudes of long period P- and SH-waveforms, recorded in the distance range of 30° - 90°, with synthetic waveforms. We further obtained finite-fault rupture histories of those earthquakes to determine the faulting area (fault length and width), maximum displacement, rupture duration and stress drop. We applied a new back-projection method that uses teleseismic P-waveforms to integrate the direct P-phase with reflected phases from structural discontinuities near the source, and customized it to estimate the spatio-temporal distribution of the seismic energy release of earthquakes. Inversion results exhibit that recent tsunamigenic earthquakes show dominantly thrust faulting mechanisms with small amount of strike-slip components. Their focal depths are also relatively shallow (h < 40 km). As an example, the September 16, 2015 Illapel (Chile) earthquake (Mw: 8.3; h: 26 km) reflects the major characteristics of the Peru-Chile subduction zone between the Nazca and South America Plates. The size, location, depth and focal mechanism of this earthquake are consistent with its occurrence on the megathrust interface in this region. This study is supported by the Scientific and Technological Research Council of Turkey (TUBITAK, Project No: CAYDAG - 114Y066).

Adiabatic description of long range frequency sweeping

NASA Astrophysics Data System (ADS)

Breizman, Boris; Nyqvist, Robert; Lilley, Matthew

2012-10-01

A theoretical framework is developed to describe long range frequency sweeping events in the 1D electrostatic bump-on-tail model with fast particle sources and collisions. The model includes three collision operators (Krook, drag (dynamical friction) and velocity space diffusion), and allows for a general shape of the fast particle distribution function. The behavior of phase space holes and clumps is analyzed, and the effect of particle trapping due to separatrix expansion is discussed. With a fast particle distribution function whose slope decays above the resonant phase velocity, hooked frequency sweeping is found for holes in the presence of drag collisions alone.

Persistent organic pollutants (POPs) in the atmosphere of coastal areas of the Ross Sea, Antarctica: Indications for long-term downward trends.

PubMed

Pozo, Karla; Martellini, Tania; Corsolini, Simonetta; Harner, Tom; Estellano, Victor; Kukučka, Petr; Mulder, Marie D; Lammel, Gerhard; Cincinelli, Alessandra

2017-07-01

Passive air samplers were used to evaluate long-term trends and spatial distribution of trace organic compounds in Antarctica. Duplicate PUF disk samplers were deployed at six automatic weather stations in the coastal area of the Ross sea (East Antarctica), between December 2010 and January 2011, during the XXVI Italian Scientific Research Expedition. Among the investigated persistent organic compounds, Hexachlorobenzene was the most abundant, with air concentrations ranging from 0.8 to 50 pg m -3 . In general, the following decreasing concentration order was found for the air samples analyzed: HCB > PeCB > PCBs > DDTs > HCHs. While HCB concentrations were in the same range as those reported in the atmosphere of other Antarctic sampling areas and did not show a decline, HCHs and DDTs levels were lower or similar to those determined one or two decades ago. In general, the very low concentrations reflected the pristine state of the East Antarctica air. Backward trajectories indicated the prevalence of air masses coming from the Antarctic continent. Local contamination and volatilization from ice were suggested as potential sources for the presence of persistent organic pollutants in the atmosphere. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatiotemporal Distribution and Alpine Behavior of Short Chain Chlorinated Paraffins in Air at Shergyla Mountain and Lhasa on the Tibetan Plateau of China.

PubMed

Wu, Jing; Gao, Wei; Liang, Yong; Fu, Jianjie; Gao, Yan; Wang, Yawei; Jiang, Guibin

2017-10-03

Pristine high-altitude mountains are ideal areas for studying the potential mechanism behind the long-range transport and environmental behavior of persistent organic pollutants in remote areas. Short chain chlorinated paraffins (SCCPs) are the most complex halogenated contaminants in the environment, and have attracted extensive worldwide interest in recent years. In this study, the spatiotemporal concentrations and distributions of SCCPs in air collected from Shergyla Mountain (located in the southeast of the Tibetan Plateau) and Lhasa were investigated during 2012-2015. Generally, the total SCCP levels at Shergyla Mountain and Lhasa were between 130 and 1300 pg/m 3 and 1100-14440 pg/m 3 , respectively. C 10 and C 11 components were the most abundant homologue groups, indicating that lighter SCCP homologue groups are capable of relatively long-range atmospheric transport. Relatively high but insignificant atmospheric SCCP concentrations at Shergyla Mountain area and Lhasa were observed from 2013 to 2015 compared with 2012. At Shergyla Mountain, SCCP concentrations on the eastern and western slopes increased with altitude, implying that "mountain cold-trapping" might occur for SCCPs. A back-trajectory model showed that SCCP sources at Shergyla Mountain and Lhasa were primarily influenced by the tropical monsoon from Southwest and South Asia.

Slotted rotatable target assembly and systematic error analysis for a search for long range spin dependent interactions from exotic vector boson exchange using neutron spin rotation

NASA Astrophysics Data System (ADS)

Haddock, C.; Crawford, B.; Fox, W.; Francis, I.; Holley, A.; Magers, S.; Sarsour, M.; Snow, W. M.; Vanderwerp, J.

2018-03-01

We discuss the design and construction of a novel target array of nonmagnetic test masses used in a neutron polarimetry measurement made in search for new possible exotic spin dependent neutron-atominteractions of Nature at sub-mm length scales. This target was designed to accept and efficiently transmit a transversely polarized slow neutron beam through a series of long open parallel slots bounded by flat rectangular plates. These openings possessed equal atom density gradients normal to the slots from the flat test masses with dimensions optimized to achieve maximum sensitivity to an exotic spin-dependent interaction from vector boson exchanges with ranges in the mm - μm regime. The parallel slots were oriented differently in four quadrants that can be rotated about the neutron beam axis in discrete 90°increments using a Geneva drive. The spin rotation signals from the 4 quadrants were measured using a segmented neutron ion chamber to suppress possible systematic errors from stray magnetic fields in the target region. We discuss the per-neutron sensitivity of the target to the exotic interaction, the design constraints, the potential sources of systematic errors which could be present in this design, and our estimate of the achievable sensitivity using this method.

Short-Chain Chlorinated Paraffins in Zurich, Switzerland--Atmospheric Concentrations and Emissions.

PubMed

Diefenbacher, Pascal S; Bogdal, Christian; Gerecke, Andreas C; Glüge, Juliane; Schmid, Peter; Scheringer, Martin; Hungerbühler, Konrad

2015-08-18

Short-chain chlorinated paraffins (SCCPs) are of concern due to their potential for adverse health effects, bioaccumulation, persistence, and long-range transport. Data on concentrations of SCCPs in urban areas and underlying emissions are still scarce. In this study, we investigated the levels and spatial distribution of SCCPs in air, based on two separate, spatially resolved sampling campaigns in the city of Zurich, Switzerland. SCCP concentrations in air ranged from 1.8 to 17 ng·m(-3) (spring 2011) and 1.1 to 42 ng·m(-3) (spring 2013) with medians of 4.3 and 2.7 ng·m(-3), respectively. Both data sets show that atmospheric SCCP levels in Zurich can vary substantially and may be influenced by a number of localized sources within this urban area. Additionally, continuous measurements of atmospheric concentrations performed at one representative sampling site in the city center from 2011 to 2013 showed strong seasonal variations with high SCCP concentrations in summer and lower levels in winter. A long-term dynamic multimedia environmental fate model was parametrized to simulate the seasonal trends of SCCP concentrations in air and to back-calculate urban emissions. Resulting annual SCCP emissions in the city of Zurich accounted for 218-321 kg, which indicates that large SCCP stocks are present in urban areas of industrialized countries.

Properties of an ideal PET perfusion tracer: new PET tracer cases and data.

PubMed

Maddahi, Jamshid

2012-02-01

An ideal positron emission tomography (PET) tracer should be highly extractable by the myocardium and able to provide high-resolution images, should enable quantification of absolute myocardial blood flow (MBF), should be compatible with both pharmacologically induced and exercise-induced stress imaging, and should not require an on-site cyclotron. The PET radionuclides nitrogen-13 ammonia and oxygen-15 water require an on-site cyclotron. Rubidium-82 may be available locally due to the generator source, but greater utilization is limited because of its relatively low myocardial extraction fraction, long positron range, and generator cost. Flurpiridaz F 18, a novel PET tracer in development, has a high-extraction fraction, short positron range, and relatively long half-life (as compared to currently available tracers), and may be produced at regional cyclotrons. Results of early clinical trials suggest that both pharmacologically and exercise-induced stress PET imaging protocols can be completed more rapidly and with lower patient radiation exposure than with single-photon emission computerized tomography (SPECT) tracers. As compared to SPECT images in the same patients, flurpiridaz F 18 PET images showed better defect contrast. Flurpiridaz F 18 is a potentially promising tracer for assessment of myocardial perfusion, measurement of absolute MBF, calculation of coronary flow reserves, and assessment of cardiac function at the peak of the stress response.

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

Bischoff, Lothar, E-mail: l.bischoff@hzdr.de; Mazarov, Paul, E-mail: Paul.Mazarov@raith.de; Bruchhaus, Lars, E-mail: Lars.Bruchhaus@raith.de

Today, Focused Ion Beam (FIB) processing is nearly exclusively based on gallium Liquid Metal Ion Sources (LMIS). But, many applications in the μm- or nm range could benefit from ion species other than gallium: local ion implantation, ion beam mixing, ion beam synthesis, or Focused Ion Beam Lithography (IBL). Therefore, Liquid Metal Alloy Ion Sources (LMAIS) represent a promising alternative to expand the remarkable application fields for FIB. Especially, the IBL process shows potential advantages over, e.g., electron beam or other lithography techniques: direct, resistless, and three-dimensional patterning, enabling a simultaneous in-situ process control by cross-sectioning and inspection. Taking additionallymore » into account that the used ion species influences significantly the physical and chemical nature of the resulting nanostructures—in particular, the electrical, optical, magnetic, and mechanic properties leading to a large potential application area which can be tuned by choosing a well suited LMAIS. Nearly half of the elements of the periodic table are recently available in the FIB technology as a result of continuous research in this area during the last forty years. Key features of a LMAIS are long life-time, high brightness, and stable ion current. Recent developments could make these sources feasible for nano patterning issues as an alternative technology more in research than in industry. The authors will review existing LMAIS, LMIS other than Ga, and binary and ternary alloys. These physical properties as well as the fabrication technology and prospective domains for modern FIB applications will similarly be reviewed. Other emerging ion sources will be also presented and their performances discussed.« less

Feasibility study of a small, thorium-based fission power system for space and terrestrial applications

NASA Astrophysics Data System (ADS)

Worrall, Michael Jason

One of the current challenges facing space exploration is the creation of a power source capable of providing useful energy for the entire duration of a mission. Historically, radioisotope batteries have been used to provide load power, but this conventional system may not be capable of sustaining continuous power for longer duration missions. To remedy this, many forays into nuclear powered spacecraft have been investigated, but no robust system for long-term power generation has been found. In this study, a novel spin on the traditional fission power system that represents a potential optimum solution is presented. By utilizing mature High Temperature Gas Reactor (HTGR) technology in conjunction with the capabilities of the thorium fuel cycle, we have created a light-weight, long-term power source capable of a continuous electric power output of up to 70kW for over 15 years. This system relies upon a combination of fissile, highly-enriched uranium dioxide and fertile thorium carbide Tri-Structural Isotropic (TRISO) fuel particles embedded in a hexagonal beryllium oxide matrix. As the primary fissile material is consumed, the fertile material breeds new fissile material leading to more steady fuel loading over the lifetime of the core. Reactor control is achieved through an innovative approach to the conventional boron carbide neutron absorber by utilizing sections of borated aluminum placed in rotating control drums within the reflector. Borated aluminum allows for much smaller boron concentrations, thus eliminating the potential for 10B(n,alpha)6Li heating issues that are common in boron carbide systems. A wide range of other reactivity control systems are also investigated, such as a radially-split rotating reflector. Lastly, an extension of the design to a terrestrial based system is investigated. In this system, uranium enrichment is dropped to 20 percent in order to meet current regulations, a solid uranium-zirconium hydride fissile driver replaces the uranium dioxide TRISO particles, and the moderating material is changed from beryllium oxide to graphite. These changes result in an increased core size, but the same long-term power generation potential is achieved. Additionally, small amounts of erbium are added to the hydride matrix to further extend core lifetime.

Effects of atmospheric variations on acoustic system performance

NASA Technical Reports Server (NTRS)

Nation, Robert; Lang, Stephen; Olsen, Robert; Chintawongvanich, Prasan

1993-01-01

Acoustic propagation over medium to long ranges in the atmosphere is subject to many complex, interacting effects. Of particular interest at this point is modeling low frequency (less than 500 Hz) propagation for the purpose of predicting ranges and bearing accuracies at which acoustic sources can be detected. A simple means of estimating how much of the received signal power propagated directly from the source to the receiver and how much was received by turbulent scattering was developed. The correlations between the propagation mechanism and detection thresholds, beamformer bearing estimation accuracies, and beamformer processing gain of passive acoustic signal detection systems were explored.

United States Air Force Annual Financial Statement 2011

DTIC Science & Technology

2011-01-01

is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources , gathering and maintaining...defenses. The B-52 Stratofortress is a long-range, nuclear and conventional heavy bomber that can perform a variety of missions. The bomber can fly...of the United States Government are deposited. Exceptions include receipts from specific sources required by law to be deposited into other

Emission source functions in heavy ion collisions

NASA Astrophysics Data System (ADS)

Shapoval, V. M.; Sinyukov, Yu. M.; Karpenko, Iu. A.

2013-12-01

Three-dimensional pion and kaon emission source functions are extracted from hydrokinetic model (HKM) simulations of central Au+Au collisions at the top Relativistic Heavy Ion Collider (RHIC) energy sNN=200 GeV. The model describes well the experimental data, previously obtained by the PHENIX and STAR collaborations using the imaging technique. In particular, the HKM reproduces the non-Gaussian heavy tails of the source function in the pair transverse momentum (out) and beam (long) directions, observed in the pion case and practically absent for kaons. The role of rescatterings and long-lived resonance decays in forming the mentioned long-range tails is investigated. The particle rescattering contribution to the out tail seems to be dominating. The model calculations also show substantial relative emission times between pions (with mean value 13 fm/c in the longitudinally comoving system), including those coming from resonance decays and rescatterings. A prediction is made for the source functions in Large Hadron Collider (LHC) Pb+Pb collisions at sNN=2.76 TeV, which are still not extracted from the measured correlation functions.

Minimally nonlocal nucleon-nucleon potentials with chiral two-pion exchange including Δ resonances

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

Piarulli, M.; Girlanda, L.; Schiavilla, R.

In this study, we construct a coordinate-space chiral potential, including Δ-isobar intermediate states in its two-pion-exchange component up to order Q 3 (Q denotes generically the low momentum scale). The contact interactions entering at next-to-leading and next-to-next-to-next-to-leading orders (Q 2 and Q 4, respectively) are rearranged by Fierz transformations to yield terms at most quadratic in the relative momentum operator of the two nucleons. The low-energy constant multiplying these contact interactions are fitted to the 2013 Granada database, consisting of 2309 pp and 2982 np data (including, respectively, 148 and 218 normalizations) in the laboratory-energy range 0–300 MeV. For themore » total 5291 $pp$ and $np$ data in this range, we obtain a Χ 2 /datum of roughly 1.3 for a set of three models characterized by long- and short-range cutoffs, R L and R S respectively, ranging from (R L,R S)=(1.2,0.8) fm down to (0.8,0.6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.« less

Minimally nonlocal nucleon-nucleon potentials with chiral two-pion exchange including Δ resonances

DOE PAGES

Piarulli, M.; Girlanda, L.; Schiavilla, R.; ...

2015-02-26

In this study, we construct a coordinate-space chiral potential, including Δ-isobar intermediate states in its two-pion-exchange component up to order Q 3 (Q denotes generically the low momentum scale). The contact interactions entering at next-to-leading and next-to-next-to-next-to-leading orders (Q 2 and Q 4, respectively) are rearranged by Fierz transformations to yield terms at most quadratic in the relative momentum operator of the two nucleons. The low-energy constant multiplying these contact interactions are fitted to the 2013 Granada database, consisting of 2309 pp and 2982 np data (including, respectively, 148 and 218 normalizations) in the laboratory-energy range 0–300 MeV. For themore » total 5291 $pp$ and $np$ data in this range, we obtain a Χ 2 /datum of roughly 1.3 for a set of three models characterized by long- and short-range cutoffs, R L and R S respectively, ranging from (R L,R S)=(1.2,0.8) fm down to (0.8,0.6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.« less

Comprehensive screening for immunodeficiency-associated vaccine-derived poliovirus: an essential oral poliovirus vaccine cessation risk management strategy.

PubMed

Duintjer Tebbens, R J; Thompson, K M

2017-01-01

If the world can successfully control all outbreaks of circulating vaccine-derived poliovirus that may occur soon after global oral poliovirus vaccine (OPV) cessation, then immunodeficiency-associated vaccine-derived polioviruses (iVDPVs) from rare and mostly asymptomatic long-term excretors (defined as ⩾6 months of excretion) will become the main source of potential poliovirus outbreaks for as long as iVDPV excretion continues. Using existing models of global iVDPV prevalence and global long-term poliovirus risk management, we explore the implications of uncertainties related to iVDPV risks, including the ability to identify asymptomatic iVDPV excretors to treat with polio antiviral drugs (PAVDs) and the transmissibility of iVDPVs. The expected benefits of expanded screening to identify and treat long-term iVDPV excretors with PAVDs range from US$0.7 to 1.5 billion with the identification of 25-90% of asymptomatic long-term iVDPV excretors, respectively. However, these estimates depend strongly on assumptions about the transmissibility of iVDPVs and model inputs affecting the global iVDPV prevalence. For example, the expected benefits may decrease to as low as US$260 million with the identification of 90% of asymptomatic iVDPV excretors if iVDPVs behave and transmit like partially reverted viruses instead of fully reverted viruses. Comprehensive screening for iVDPVs will reduce uncertainties and maximize the expected benefits of PAVD use.

Real-time measurement of volcanic SO2 emissions: Validation of a new UV correlation spectrometer (FLYSPEC)

USGS Publications Warehouse

Horton, Keith A.; Williams-Jones, Glyn; Garbeil, Harold; Elias, Tamar; Sutton, A. Jeff; Mouginis-Mark, Peter J; Porter, John T.; Clegg, Steven

2006-01-01

A miniaturized, lightweight and low-cost UV correlation spectrometer, the FLYSPEC, has been developed as an alternative for the COSPEC, which has long been the mainstay for monitoring volcanic sulfur dioxide fluxes. Field experiments have been conducted with the FLYSPEC at diverse volcanic systems, including Masaya (Nicaragua), Poás (Costa Rica), Stromboli, Etna and Vulcano (Italy), Villarica (Chile) and Kilauea (USA). We present here those validation measurements that were made simultaneously with COSPEC at Kilauea between March 2002 and February 2003. These experiments, with source emission rates that ranged from 95 to 1,560 t d−1, showed statistically identical results from both instruments. SO2 path-concentrations ranged from 0 to >1,000 ppm-m with average correlation coefficients greater than r2=0.946. The small size and low cost create the opportunity for FLYSPEC to be used in novel deployment modes that have the potential to revolutionize the manner in which volcanic and industrial monitoring is performed.

Radon Levels Measured at a Touristic Thermal Spa Resort in Montagu (South Africa) and Associated Effective Doses.

PubMed

Botha, R; Newman, R T; Maleka, P P

2016-09-01

Radon activity concentrations (in water and in air) were measured at 13 selected locations at the Avalon Springs thermal spa resort in Montagu (Western Cape, South Africa) to estimate the associated effective dose received by employees and visitors. A RAD-7 detector (DURRIDGE), based on alpha spectrometry, and electret detectors (E-PERM®Radelec) were used for these radon measurements. The primary source of radon was natural thermal waters from the hot spring, which were pumped to various locations on the resort, and consequently a range of radon in-water analyses were performed. Radon in-water activity concentration as a function of time (short term and long term measurements) and spatial distributions (different bathing pools, etc.) were studied. The mean radon in-water activity concentrations were found to be 205 ± 6 Bq L (source), 112 ± 5 Bq L (outdoor pool) and 79 ± 4 Bq L (indoor pool). Radon in-air activity concentrations were found to range between 33 ± 4 Bq m (at the outside bar) to 523 ± 26 Bq m (building enclosing the hot spring's source). The most significant potential radiation exposure identified is that due to inhalation of air rich in radon and its progeny by the resort employees. The annual occupational effective dose due to the inhalation of radon progeny ranges from 0.16 ± 0.01 mSv to 0.40 ± 0.02 mSv. For the water samples collected, the Ra in-water activity concentrations from samples collected were below the lower detection limit (~0.7 Bq L) of the γ-ray detector system used. No significant radiological health risk can be associated with radon and progeny from the hot spring at the Avalon Springs resort.

Enhanced SO2 Concentrations Observed over Northern India: Role of Long-range Transport

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

Mallik, C.; Lal, S.; Naja, M.

2013-01-17

Volcanic emissions and coal burning are among the major sources of SO2 over the continental environment. In this study, we show episodes of long-range transport of volcanic SO2 from Africa to Northern India using satellite observations. Monthly averaged SO2 from OMI were of the order of 0.6-0.9 DU during November, 2008 over the Indo-Gangetic Plain (IGP), which far exceeded background values (<0.3 DU) retrieved from observations across different locations over North India during 2005-2010. The columnar SO2 loadings were much higher on November 6 over most of the IGP and even exceeded 6 DU, a factor of 10 higher thanmore » background levels at some places. These enhanced SO2 levels were, however, not reciprocated in satellite derived NO2 or CO columns, indicating transport from a non-anthropogenic source of SO2. Backward trajectory analysis revealed strong winds in the free troposphere, which originated from the Dalaffilla volcanic eruption over the Afar region of Ethiopia during November 4-6, 2008. Wind streams and stable atmospheric conditions were conducive to the long-range transport of volcanic plume into the IGP. As most of the local aerosols over IGP region are below 3 km, a well separated layer at 4-5 km is observed from CALIPSO, most likely as a result of this transport. Apart from known anthropogenic sources, the additional transport of volcanic SO2 over the IGP region would have implications to air quality and radiation balance over this region.« less

betaFIT: A computer program to fit pointwise potentials to selected analytic functions

NASA Astrophysics Data System (ADS)

Le Roy, Robert J.; Pashov, Asen

2017-01-01

This paper describes program betaFIT, which performs least-squares fits of sets of one-dimensional (or radial) potential function values to four different types of sophisticated analytic potential energy functional forms. These families of potential energy functions are: the Expanded Morse Oscillator (EMO) potential [J Mol Spectrosc 1999;194:197], the Morse/Long-Range (MLR) potential [Mol Phys 2007;105:663], the Double Exponential/Long-Range (DELR) potential [J Chem Phys 2003;119:7398], and the "Generalized Potential Energy Function (GPEF)" form introduced by Šurkus et al. [Chem Phys Lett 1984;105:291], which includes a wide variety of polynomial potentials, such as the Dunham [Phys Rev 1932;41:713], Simons-Parr-Finlan [J Chem Phys 1973;59:3229], and Ogilvie-Tipping [Proc R Soc A 1991;378:287] polynomials, as special cases. This code will be useful for providing the realistic sets of potential function shape parameters that are required to initiate direct fits of selected analytic potential functions to experimental data, and for providing better analytical representations of sets of ab initio results.

Radiotherapy for benign disease; assessing the risk of radiation-induced cancer following exposure to intermediate dose radiation

PubMed Central

Hatfield, Paul; Prestwich, Robin JD; Shaffer, Richard E; Taylor, Roger E

2015-01-01

Most radiotherapy (RT) involves the use of high doses (>50 Gy) to treat malignant disease. However, low to intermediate doses (approximately 3–50 Gy) can provide effective control of a number of benign conditions, ranging from inflammatory/proliferative disorders (e.g. Dupuytren's disease, heterotopic ossification, keloid scarring, pigmented villonodular synovitis) to benign tumours (e.g. glomus tumours or juvenile nasopharyngeal angiofibromas). Current use in UK RT departments is very variable. This review identifies those benign diseases for which RT provides good control of symptoms with, for the most part, minimal side effects. However, exposure to radiation has the potential to cause a radiation-induced cancer (RIC) many years after treatment. The evidence for the magnitude of this risk comes from many disparate sources and is constrained by the small number of long-term studies in relevant clinical cohorts. This review considers the types of evidence available, i.e. theoretical models, phantom studies, epidemiological studies, long-term follow-up of cancer patients and those treated for benign disease, although many of the latter data pertain to treatments that are no longer used. Informative studies are summarized and considered in relation to the potential for development of a RIC in a range of key tissues (skin, brain etc.). Overall, the evidence suggests that the risks of cancer following RT for benign disease for currently advised protocols are small, especially in older patients. However, the balance of risk vs benefit needs to be considered in younger adults and especially if RT is being considered in adolescents or children. PMID:26462717

Noise pair velocity and range echo location system

DOEpatents

Erskine, D.J.

1999-02-16

An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution is disclosed. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path. Speckle in the image of target and antenna lobing due to parasitic reflections is minimal for an incoherent source. An arbitrary source which varies its spectrum dramatically and randomly from pulse to pulse creates a radar elusive to jamming. Monochromatic sources which jigger in frequency from pulse to pulse or combinations of monochromatic sources can simulate some benefits of incoherent broadband sources. Clutter which has a symmetrical velocity spectrum will self-cancel for short wavelengths, such as the apparent motion of ground surrounding target from a sidelooking airborne antenna. 46 figs.

Noise pair velocity and range echo location system

DOEpatents

Erskine, David J.

1999-01-01

An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path. Speckle in the image of target and antenna lobing due to parasitic reflections is minimal for an incoherent source. An arbitrary source which varies its spectrum dramatically and randomly from pulse to pulse creates a radar elusive to jamming. Monochromatic sources which jigger in frequency from pulse to pulse or combinations of monochromatic sources can simulate some benefits of incoherent broadband sources. Clutter which has a symmetrical velocity spectrum will self-cancel for short wavelengths, such as the apparent motion of ground surrounding target from a sidelooking airborne antenna.

Connecting Surface Emissions, Convective Uplifting, and Long-Range Transport of Carbon Monoxide in the Upper Troposphere: New Observations from the Aura Microwave Limb Sounder

NASA Technical Reports Server (NTRS)

Jiang, Jonathan H.; Livesey, Nathaniel J.; Su, Hui; Neary, Lori; McConnell, John C.; Richards, Nigel A. D.

2007-01-01

Two years of observations of upper tropospheric (UT) carbon monoxide (CO) from the Aura Microwave Limb Sounder are analyzed; in combination with the CO surface emission climatology and data from the NCEP analyses. It is shown that spatial distribution, temporal variation and long-range transport of UT CO are closely related to the surface emissions, deep-convection and horizontal winds. Over the Asian monsoon region, surface emission of CO peaks in boreal spring due to high biomass burning in addition to anthropogenic emission. However, the UT CO peaks in summer when convection is strongest and surface emission of CO is dominated by anthropogenic source. The long-range transport of CO from Southeast Asia across the Pacific to North America, which occurs most frequently during boreal summer, is thus a clear imprint of Asian anthropogenic pollution influencing global air quality.

Energy recovery from organic fractions of municipal solid waste: A case study of Hyderabad city, Pakistan.

PubMed

Safar, Korai M; Bux, Mahar R; Aslam, Uqaili M; Ahmed, Memon S; Ahmed, Lashari I

2016-04-01

Non-renewable energy sources have remained the choice of the world for centuries. Rapid growth in population and industrialisation have caused their shortage and environmental degradation by using them. Thus, at the present rate of consumption, they will not last very long. In this prospective, this study has been conducted. The estimation of energy in terms of biogas and heat from various organic fractions of municipal solid waste is presented and discussed. The results show that organic fractions of municipal solid waste possess methane potential in the range of 3%-22% and their heat capacity ranges from 3007 to 20,099 kJ kg(-1) Also, theoretical biogas potential of different individual fruit as well as vegetable components and mixed food waste are analysed and estimated in the range of 608-1244 m(3) t(-1) Further, the share of bioenergy from municipal solid waste in the total primary energy supply in Pakistan has been estimated to be 1.82%. About 8.43% of present energy demand of the country could be met from municipal solid waste. The study leads us to the conclusion that the share of imported energy (i.e. 0.1% of total energy supply) and reduction in the amount of energy from fossil fuels can be achieved by adopting a waste-to-energy system in the country. © The Author(s) 2016.

Taking potential probability function maps to the local scale and matching them with land use maps

NASA Astrophysics Data System (ADS)

Garg, Saryu; Sinha, Vinayak; Sinha, Baerbel

2013-04-01

Source-Receptor models have been developed using different methods. Residence-time weighted concentration back trajectory analysis and Potential Source Contribution Function (PSCF) are the two most popular techniques for identification of potential sources of a substance in a defined geographical area. Both techniques use back trajectories calculated using global models and assign values of probability/concentration to various locations in an area. These values represent the probability of threshold exceedances / the average concentration measured at the receptor in air masses with a certain residence time over a source area. Both techniques, however, have only been applied to regional and long-range transport phenomena due to inherent limitation with respect to both spatial accuracy and temporal resolution of the of back trajectory calculations. Employing the above mentioned concepts of residence time weighted concentration back-trajectory analysis and PSCF, we developed a source-receptor model capable of identifying local and regional sources of air pollutants like Particulate Matter (PM), NOx, SO2 and VOCs. We use 1 to 30 minute averages of concentration values and wind direction and speed from a single receptor site or from multiple receptor sites to trace the air mass back in time. The model code assumes all the atmospheric transport to be Lagrangian and linearly extrapolates air masses reaching the receptor location, backwards in time for a fixed number of steps. We restrict the model run to the lifetime of the chemical species under consideration. For long lived species the model run is limited to < 4 hrs as spatial uncertainty increases the longer an air mass is linearly extrapolated back in time. The final model output is a map, which can be compared with the local land use map to pinpoint sources of different chemical substances and estimate their source strength. Our model has flexible space- time grid extrapolation steps of 1-5 minutes and 1-5 km grid resolution. By making use of high temporal resolution data, our model can produce maps for different times of the day, thus accounting for temporal changes and activity profiles of different sources. The main advantage of our approach compared to geostationary numerical methods that interpolate measured concentration values of multiple measurement sites to produce maps (gridding) is that the maps produced are more accurate in terms of spatial identification of sources. The model was applied to isoprene and meteorological data recorded during clean post-monsoon season (1 October- 7 October, 2012) between 11 am and 4 pm at a receptor site in the North-West Indo-Gangetic Plains (IISER Mohali, 30.665° N, 76.729°E, 300 m asl), near the foothills of the Himalayan range. Considering the lifetime of isoprene, the model was run only 2 hours backward in time. The map shows highest residence time weighted concentration of isoprene (up to 3.5 ppbv) over agricultural land with high number of trees (>180 trees/gridsquare); moderate concentrations for agricultural lands with low tree density (1.5-2.5 ppbv for 250 μg/m3 for traffic hotspots in Chandigarh City are observed. Based on the validation against the land use maps, the model appears to do an excellent job in source apportionment and identifying emission hotspots. Acknowledgement: We thank the IISER Mohali Atmospheric Chemistry Facility for data and the Ministry of Human Resource Development (MHRD), India and IISER Mohali for funding the facility. Chinmoy Sarkar is acknowledged for technical support, Saryu Garg thanks the Max Planck-DST India Partner Group on Tropospheric OH reactivity and VOCs for funding the research.

Microcombustor-thermoelectric power generator for 10-50 watt applications

NASA Astrophysics Data System (ADS)

Marshall, Daniel S.; Cho, Steve T.

2010-04-01

Fuel-based portable power systems, including combustion and fuel cell systems, take advantage of the 80x higher energy density of fuel over lithium battery technologies and offer the potential for much higher energy density power sources - especially for long-duration applications, such as unattended sensors. Miniaturization of fuel-based systems poses significant challenges, including processing of fuel in small channels, catalyst poisoning, and coke and soot formation. Recent advances in micro-miniature combustors in the 200Watt thermal range have enabled the development of small power sources that use the chemical energy of heavy fuel to drive thermal-to-electric converters for portable applications. CUBE Technology has developed compact Micro-Furnace combustors that efficiently deliver high-quality heat to optimized thermal-to-electric power converters, such as advanced thermoelectric power modules and Stirling motors, for portable power generation at the 10-50Watt scale. Key innovations include a compact gas-gas recuperator, innovative heavy fuel processing, coke- & soot-free operation, and combustor optimization for low balance-of-plant power use while operating at full throttle. This combustor enables the development of robust, high energy density, miniature power sources for portable applications.

The role of airborne mineral dusts in human disease

USGS Publications Warehouse

Morman, Suzette A.; Plumlee, Geoffrey S.

2013-01-01

Exposure to fine particulate matter (PM) is generally acknowledged to increase risk for human morbidity and mortality. However, particulate matter (PM) research has generally examined anthropogenic (industry and combustion by-products) sources with few studies considering contributions from geogenic PM (produced from the Earth by natural processes, e.g., volcanic ash, windborne ash from wildfires, and mineral dusts) or geoanthropogenic PM (produced from natural sources by processes that are modified or enhanced by human activities, e.g., dusts from lakebeds dried by human removal of water, dusts produced from areas that have undergone desertification as a result of human practices). Globally, public health concerns are mounting, related to potential increases in dust emission from climate related changes such as desertification and the associated long range as well as local health effects. Recent epidemiological studies have identified associations between far-traveled dusts from primary sources and increased morbidity and mortality in Europe and Asia. This paper provides an outline of public health research and history as it relates to naturally occurring inorganic mineral dusts. We summarize results of current public health research and describe some of the many challenges related to understanding health effects from exposures to dust aerosols.

Source localization in an ocean waveguide using supervised machine learning.

PubMed

Niu, Haiqiang; Reeves, Emma; Gerstoft, Peter

2017-09-01

Source localization in ocean acoustics is posed as a machine learning problem in which data-driven methods learn source ranges directly from observed acoustic data. The pressure received by a vertical linear array is preprocessed by constructing a normalized sample covariance matrix and used as the input for three machine learning methods: feed-forward neural networks (FNN), support vector machines (SVM), and random forests (RF). The range estimation problem is solved both as a classification problem and as a regression problem by these three machine learning algorithms. The results of range estimation for the Noise09 experiment are compared for FNN, SVM, RF, and conventional matched-field processing and demonstrate the potential of machine learning for underwater source localization.

Experimental study of the thermal-acoustic efficiency in a long turbulent diffusion-flame burner

NASA Technical Reports Server (NTRS)

Mahan, J. R.

1983-01-01

An acoustic source/propagation model is used to interpret measured noise spectra from a long turbulent burner. The acoustic model is based on the perturbation solution of the equations describing the unsteady one-dimensional flow of an inviscid ideal gas with a distributed heat source. The model assumes that the measured noise spectra are due uniquely to the unsteady component of combustion heat release. The model was applied to a long cylindrical hydrogen burner operating over a range of power levels between 4.5 kW and 22.3 kW. Acoustic impedances at the inlet to the burner and at the exit of the tube downstream of the burner were measured and are used as boundary conditions for the model. These measured impedances are also presented.

Chaos of energetic positron orbits in a dipole magnetic field and its potential application to a new injection scheme

NASA Astrophysics Data System (ADS)

Saitoh, H.; Yoshida, Z.; Yano, Y.; Nishiura, M.; Kawazura, Y.; Horn-Stanja, J.; Pedersen, T. Sunn

2016-10-01

We study the behavior of high-energy positrons emitted from a radioactive source in a magnetospheric dipole field configuration. Because the conservation of the first and second adiabatic invariants is easily destroyed in a strongly inhomogeneous dipole field for high-energy charged particles, the positron orbits are nonintegrable, resulting in chaotic motions. In the geometry of a typical magnetospheric levitated dipole experiment, it is shown that a considerable ratio of positrons from a 22Na source, located at the edge of the confinement region, has chaotic long orbit lengths before annihilation. These particles make multiple toroidal circulations and form a hollow toroidal positron cloud. Experiments with a small 22Na source in the Ring Trap 1 (RT-1) device demonstrated the existence of such long-lived positrons in a dipole field. Such a chaotic behavior of high-energy particles is potentially applicable to the formation of a dense toroidal positron cloud in the strong-field region of the dipole field in future studies.

Fire Source Localization Based on Distributed Temperature Sensing by a Dual-Line Optical Fiber System.

PubMed

Sun, Miao; Tang, Yuquan; Yang, Shuang; Li, Jun; Sigrist, Markus W; Dong, Fengzhong

2016-06-06

We propose a method for localizing a fire source using an optical fiber distributed temperature sensor system. A section of two parallel optical fibers employed as the sensing element is installed near the ceiling of a closed room in which the fire source is located. By measuring the temperature of hot air flows, the problem of three-dimensional fire source localization is transformed to two dimensions. The method of the source location is verified with experiments using burning alcohol as fire source, and it is demonstrated that the method represents a robust and reliable technique for localizing a fire source also for long sensing ranges.

Wood wastes and residues generated along the Colorado Front Range as a potential fuel source

Treesearch

Julie E. Ward; Kurt H. Mackes; Dennis L. Lynch

2004-01-01

Throughout the United States there is interest in utilizing renewable fuel sources as an alternative to coal and nat-ural gas. This project was initiated to determine the availability of wood wastes and residues for use as fuel in ce-ment kilns and power plants located along the Colorado Front Range. Research was conducted through literature searches, phone surveys,...

Operational source receptor calculations for large agglomerations

NASA Astrophysics Data System (ADS)

Gauss, Michael; Shamsudheen, Semeena V.; Valdebenito, Alvaro; Pommier, Matthieu; Schulz, Michael

2016-04-01

For Air quality policy an important question is how much of the air pollution within an urbanized region can be attributed to local sources and how much of it is imported through long-range transport. This is critical information for a correct assessment of the effectiveness of potential emission measures. The ratio between indigenous and long-range transported air pollution for a given region depends on its geographic location, the size of its area, the strength and spatial distribution of emission sources, the time of the year, but also - very strongly - on the current meteorological conditions, which change from day to day and thus make it important to provide such calculations in near-real-time to support short-term legislation. Similarly, long-term analysis over longer periods (e.g. one year), or of specific air quality episodes in the past, can help to scientifically underpin multi-regional agreements and long-term legislation. Within the European MACC projects (Monitoring Atmospheric Composition and Climate) and the transition to the operational CAMS service (Copernicus Atmosphere Monitoring Service) the computationally efficient EMEP MSC-W air quality model has been applied with detailed emission data, comprehensive calculations of chemistry and microphysics, driven by high quality meteorological forecast data (up to 96-hour forecasts), to provide source-receptor calculations on a regular basis in forecast mode. In its current state, the product allows the user to choose among different regions and regulatory pollutants (e.g. ozone and PM) to assess the effectiveness of fictive emission reductions in air pollutant emissions that are implemented immediately, either within the agglomeration or outside. The effects are visualized as bar charts, showing resulting changes in air pollution levels within the agglomeration as a function of time (hourly resolution, 0 to 4 days into the future). The bar charts not only allow assessing the effects of emission reduction measures but they also indicate the relative importance of indigenous versus imported air pollution. The calculations are currently performed weekly by MET Norway for the Paris, London, Berlin, Oslo, Po Valley and Rhine-Ruhr regions and the results are provided free of charge at the MACC website (http://www.gmes-atmosphere.eu/services/aqac/policy_interface/regional_sr/). A proposal to extend this service to all EU capitals on a daily basis within the Copernicus Atmosphere Monitoring Service is currently under review. The tool is an important example illustrating the increased application of scientific tools to operational services that support Air Quality policy. This paper will describe this tool in more detail, focusing on the experimental setup, underlying assumptions, uncertainties, computational demand, and the usefulness for air quality for policy. Options to apply the tool for agglomerations outside the EU will also be discussed (making reference to, e.g., PANDA, which is a European-Chinese collaboration project).

Temporal interference with frequency-controllable long photons from independent cold atomic sources

NASA Astrophysics Data System (ADS)

Qian, Peng; Gu, Zhenjie; Wen, Rong; Zhang, Weiping; Chen, J. F.

2018-01-01

The interference of single photons from independent sources is an essential tool in quantum information processing. However, the interfering of photons with long temporal states in a time-resolved manner has rarely been studied. This is because without transmitting spectral filters or coupling to a cavity mode single photons generated in traditional nonlinear crystals suffer from a short temporal profile below 1 ns. With spectral correlation maintained in the biphotons generated from spontaneous four-wave mixing process in cold atom clouds, here we demonstrate the temporal interference of two frequency-tunable long photons from two independent cold atomic sources. We observe and analyze the interference of frequency-mismatched photons, where the phenomenon of the quantum beat at megahertz separation is displayed. Our paper provides more details for the quantum beat of two independent narrow-band single photons, which may find potential application in frequency-encoded photonic qubits in quantum information processing.

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

Brauner, Edwin Jr.; Carlson, Daniel C.

The Geysers steamfields in northern Sonoma County have produced reliable ''green'' power for many years. An impediment to long-term continued production has been the ability to provide a reliable source of injection water to replace water extracted and lost in the form of steam. The steamfield operators have historcially used cooling towers to recycle a small portion of the steam and have collected water during the winter months using stream extraction. These two sources, however, could not by themselves sustain the steamfield in the long term. The Lake County Reclaimed Water Project (SEGEP) was inititated in 1997 and provides anothermore » source of steamfield replenishment water. The Santa Rosa Geysers Recharge Project provides another significant step in replenishing the steamfield. In addition, the Santa Rosa Geysers Recharge Project has been built with capacity to potentially meet virtually all injection water requirements, when combined with these other sources. Figure 2.1 graphically depicts the combination of injection sources.« less

Talking Pictures: Exploiting the Potential of Visual Sources to Generate Productive Pupil Talk

ERIC Educational Resources Information Center

Card, Jane

2012-01-01

Jane Card has long been fascinated by the power of visual sources to stimulate pupil thought and discussion. In previous articles she has shared insights from her own expert practice, fusing deep subject knowledge with careful planning to generate highly skilful questioning. Here she presents another rich example of classroom practice, carefully…

Mapping cortical hubs in tinnitus

PubMed Central

2009-01-01

Background Subjective tinnitus is the perception of a sound in the absence of any physical source. It has been shown that tinnitus is associated with hyperactivity of the auditory cortices. Accompanying this hyperactivity, changes in non-auditory brain structures have also been reported. However, there have been no studies on the long-range information flow between these regions. Results Using Magnetoencephalography, we investigated the long-range cortical networks of chronic tinnitus sufferers (n = 23) and healthy controls (n = 24) in the resting state. A beamforming technique was applied to reconstruct the brain activity at source level and the directed functional coupling between all voxels was analyzed by means of Partial Directed Coherence. Within a cortical network, hubs are brain structures that either influence a great number of other brain regions or that are influenced by a great number of other brain regions. By mapping the cortical hubs in tinnitus and controls we report fundamental group differences in the global networks, mainly in the gamma frequency range. The prefrontal cortex, the orbitofrontal cortex and the parieto-occipital region were core structures in this network. The information flow from the global network to the temporal cortex correlated positively with the strength of tinnitus distress. Conclusion With the present study we suggest that the hyperactivity of the temporal cortices in tinnitus is integrated in a global network of long-range cortical connectivity. Top-down influence from the global network on the temporal areas relates to the subjective strength of the tinnitus distress. PMID:19930625

Impact of Siberian forest fires on the atmosphere over the Korean Peninsula during summer 2014

NASA Astrophysics Data System (ADS)

Jung, Jinsang; Lyu, Youngsook; Lee, Minhee; Hwang, Taekyung; Lee, Sangil; Oh, Sanghyub

2016-06-01

Extensive forest fires occurred during late July 2014 across the forested region of Siberia, Russia. Smoke plumes emitted from Siberian forest fires underwent long-range transport over Mongolia and northeast China to the Korean Peninsula, which is located ˜ 3000 km south of the Siberian forest. A notably high aerosol optical depth of ˜ 4 was observed at a wavelength of 500 nm near the source of the Siberian forest fires. Smoke plumes reached 3-5 km in height near the source and fell below 2 km over the Korean Peninsula. Elevated concentrations of levoglucosan were observed (119.7 ± 6.0 ng m-3), which were ˜ 4.5 times higher than those observed during non-event periods in July 2014. During the middle of July 2014, a haze episode occurred that was primarily caused by the long-range transport of emission plumes originating from urban and industrial complexes in East China. Sharp increases in SO42- concentrations (23.1 ± 2.1 µg m-3) were observed during this episode. The haze caused by the long-range transport of Siberian forest fire emissions was clearly identified by relatively high organic carbon (OC) / elemental carbon (EC) ratios (7.18 ± 0.2) and OC / SO42- ratios (1.31 ± 0.07) compared with those of the Chinese haze episode (OC / EC ratio: 2.4 ± 0.4; OC / SO42- ratio: 0.21 ± 0.05). Remote measurement techniques and chemical analyses of the haze plumes clearly show that the haze episode that occurred during late July 2014 was caused mainly by the long-range transport of smoke plumes emitted from Siberian forest fires.

Colorado air quality impacted by long-range-transported aerosol: a set of case studies during the 2015 Pacific Northwest fires

NASA Astrophysics Data System (ADS)

Creamean, Jessie M.; Neiman, Paul J.; Coleman, Timothy; Senff, Christoph J.; Kirgis, Guillaume; Alvarez, Raul J.; Yamamoto, Atsushi

2016-09-01

Biomass burning plumes containing aerosols from forest fires can be transported long distances, which can ultimately impact climate and air quality in regions far from the source. Interestingly, these fires can inject aerosols other than smoke into the atmosphere, which very few studies have evidenced. Here, we demonstrate a set of case studies of long-range transport of mineral dust aerosols in addition to smoke from numerous fires (including predominantly forest fires and a few grass/shrub fires) in the Pacific Northwest to Colorado, US. These aerosols were detected in Boulder, Colorado, along the Front Range using beta-ray attenuation and energy-dispersive X-ray fluorescence spectroscopy, and corroborated with satellite-borne lidar observations of smoke and dust. Further, we examined the transport pathways of these aerosols using air mass trajectory analysis and regional- and synoptic-scale meteorological dynamics. Three separate events with poor air quality and increased mass concentrations of metals from biomass burning (S and K) and minerals (Al, Si, Ca, Fe, and Ti) occurred due to the introduction of smoke and dust from regional- and synoptic-scale winds. Cleaner time periods with good air quality and lesser concentrations of biomass burning and mineral metals between the haze events were due to the advection of smoke and dust away from the region. Dust and smoke present in biomass burning haze can have diverse impacts on visibility, health, cloud formation, and surface radiation. Thus, it is important to understand how aerosol populations can be influenced by long-range-transported aerosols, particularly those emitted from large source contributors such as wildfires.

Electron Localization in Dissociating H 2 + by Retroaction of a Photoelectron onto Its Source

DOE PAGES

Waitz, M.; Asliturk, D.; Wechselberger, N.; ...

2016-01-26

We investigate the dissociation of H 2 + into a proton and a H 0 after single ionization with photons of an energy close to the threshold. We find that the p + and the H 0 do not emerge symmetrically in the case of the H 2 + dissociating along the 1sσ g ground state. Instead, a preference for the ejection of the p + in the direction of the escaping photoelectron can be observed. This symmetry breaking is strongest for very small electron energies. Our experiment is consistent with a recent prediction by Serov and Kheifets. In theirmore » model, which treats the photoelectron classically, the symmetry breaking is induced by the retroaction of the long-range Coulomb potential onto the dissociating H 2 +.« less

Single Frequency Monolithic Solid State Green Laser as a Potential Source for Vibrometry Systems

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

Sotor, Jaroslaw Z.; Antonczak, Arkadiusz J.; Abramski, Krzysztof M.

2010-05-28

In this paper miniature, monolithic single frequency solid state laser operating at 532 nm is presented. Developed Nd:GdVO{sub 4}/YVO{sub 4}/KTP consist of three crystal bonded together with a UV adhesive. The single frequency operation was obtained in wide temperature range from 17 deg. C to 27 deg. C. The laser operated with output power up to 90 mW at 532 nm. The total optical efficiency (808 nm to 532 nm) was 9.5%. Power stability was at the level of +-0.8% and the long term frequency stability was approximately 3centre dot10{sup -8}. The beam has a Gaussian profile and the M2more » parameter was below 1.1.« less

Families in the Army: Looking Ahead

DTIC Science & Technology

1989-06-01

WRi 0ata FEA14-64) This study considers how aggregate demand for Army family services will change in the future and identifies long-range issues posed...although Army actions and policies could potentially modify that future. Four long-range issues deserve closer study and continued monitoring: (1...important issues those changes pose, and explores their implications for force manage- ment and service delivery policies. It is meant to provide RAND and

Describing long-range charge-separation processes with subsystem density-functional theory

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

Solovyeva, Alisa; Neugebauer, Johannes, E-mail: j.neugebauer@uni-muenster.de; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu

2014-04-28

Long-range charge-transfer processes in extended systems are difficult to describe with quantum chemical methods. In particular, cost-effective (non-hybrid) approximations within time-dependent density functional theory (DFT) are not applicable unless special precautions are taken. Here, we show that the efficient subsystem DFT can be employed as a constrained DFT variant to describe the energetics of long-range charge-separation processes. A formal analysis of the energy components in subsystem DFT for such excitation energies is presented, which demonstrates that both the distance dependence and the long-range limit are correctly described. In addition, electronic couplings for these processes as needed for rate constants inmore » Marcus theory can be obtained from this method. It is shown that the electronic structure of charge-separated states constructed by a positively charged subsystem interacting with a negatively charged one is difficult to converge — charge leaking from the negative subsystem to the positive one can occur. This problem is related to the delocalization error in DFT and can be overcome with asymptotically correct exchange–correlation (XC) potentials or XC potentials including a sufficiently large amount of exact exchange. We also outline an approximate way to obtain charge-transfer couplings between locally excited and charge-separated states.« less

ADRPM-VII applied to the long-range acoustic detection problem

NASA Technical Reports Server (NTRS)

Shalis, Edward; Koenig, Gerald

1990-01-01

An acoustic detection range prediction model (ADRPM-VII) has been written for IBM PC/AT machines running on the MS-DOS operating system. The software allows the user to predict detection distances of ground combat vehicles and their associated targets when they are involved in quasi-military settings. The program can also calculate individual attenuation losses due to spherical spreading, atmospheric absorption, ground reflection and atmospheric refraction due to temperature and wind gradients while varying parameters effecting the source-receiver problem. The purpose here is to examine the strengths and limitations of ADRPM-VII by modeling the losses due to atmospheric refraction and ground absorption, commonly known as excess attenuation, when applied to the long range detection problem for distances greater than 3 kilometers.

Deep seafloor arrivals: an unexplained set of arrivals in long-range ocean acoustic propagation.

PubMed

Stephen, Ralph A; Bolmer, S Thompson; Dzieciuch, Matthew A; Worcester, Peter F; Andrew, Rex K; Buck, Linda J; Mercer, James A; Colosi, John A; Howe, Bruce M

2009-08-01

Receptions, from a ship-suspended source (in the band 50-100 Hz) to an ocean bottom seismometer (about 5000 m depth) and the deepest element on a vertical hydrophone array (about 750 m above the seafloor) that were acquired on the 2004 Long-Range Ocean Acoustic Propagation Experiment in the North Pacific Ocean, are described. The ranges varied from 50 to 3200 km. In addition to predicted ocean acoustic arrivals and deep shadow zone arrivals (leaking below turning points), "deep seafloor arrivals," that are dominant on the seafloor geophone but are absent or very weak on the hydrophone array, are observed. These deep seafloor arrivals are an unexplained set of arrivals in ocean acoustics possibly associated with seafloor interface waves.

Long-range, full-duplex, modulated-reflector cell phone for voice/data transmission

DOEpatents

Neagley, Daniel L.; Briles, Scott D.; Coates, Don M.; Freund, Samuel M.

2002-01-01

A long-range communications apparatus utilizing modulated-reflector technology is described. The apparatus includes an energy-transmitting base station and remote units that do not emit radiation in order to communicate with the base station since modulated-reflector technology is used whereby information is attached to an RF carrier wave originating from the base station which is reflected by the remote unit back to the base station. Since the remote unit does not emit radiation, only a low-power power source is required for its operation. Information from the base station is transmitted to the remote unit using a transmitter and receiver, respectively. The range of such a communications system is determined by the properties of a modulated-reflector half-duplex link.

Used motor oil as a source of MTBE, TAME, and BTEX to ground water

USGS Publications Warehouse

Baker, R.J.; Best, E.W.; Baehr, A.L.

2002-01-01

Methyl tert-butyl ether (MTBE), the widely used gasoline oxygenate, has been identified as a common ground water contaminant, and BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) have long been associated with gasoline spills. Because not all instances of ground water contamination by MTBE and BTEX can be attributed to spills or leaking storage tanks, other potential sources need to be considered. In this study, used motor oil was investigated as a potential source of these contaminants. MTBE in oil was measured directly by methanol extraction and gas chromatography using a flame ionization detector (GC/FID). Water was equilibrated with oil samples and analyzed for MTBE, BTEX, and the oxygenate tert-amyl methyl ether (TAME) by purge-and-trap concentration followed by GC/FID analysis. Raoult's law was used to calculate oil-phase concentrations of MTBE, BTEX, and TAME from aqueous-phase concentrations. MTBE, TAME, and BTEX were not detected in any of five new motor oil samples, whereas these compounds were found at significant concentrations in all six samples of the used motor oil tested for MTBE and all four samples tested for TAME and BTEX. MTBE concentrations in used motor oil were on the order of 100 mg/L. TAME concentrations ranged from 2.2 to 87 mg/L. Concentrations of benzene were 29 to 66 mg/L, but those of other BTEX compounds were higher, typically 500 to 2000 mg/L.

Low Energy Nuclear Reaction Aircraft- 2013 ARMD Seedling Fund Phase I Project

NASA Technical Reports Server (NTRS)

Wells, Douglas P.; McDonald, Robert; Campbell, Robbie; Chase, Adam; Daniel, Jason; Darling, Michael; Green, Clayton; MacGregor, Collin; Sudak, Peter; Sykes, Harrison;

Uncertainty and research needs for supplementing wild populations of anadromous Pacific salmon

USGS Publications Warehouse

Reisenbichler, R.R.

2005-01-01

Substantial disagreement and uncertainty attend the question of whether the benefits from supplementing wild populations of anadromous salmonids with hatchery fish outweigh the risks. Prudent decisions about supplementation are most likely when the suite of potential benefits and hazards and the various sources of uncertainty are explicitly identified. Models help by indicating the potential consequences of various levels of supplementation but perhaps are most valuable for showing the limitations of available data and helping design studies and monitoring to provide critical data. Information and understanding about the issue are deficient. I discuss various benefits, hazards, and associated uncertainties for supplementation, and implications for the design of monitoring and research. Several studies to reduce uncertainty and facilitate prudent supplementation are described and range from short-term reductionistic studies that help define the issue or help avoid deleterious consequences from supplementation to long-term studies (ca. 10 or more fish generations) that evaluate the net result of positive and negative genetic, behavioral, and ecological effects from supplementation.

Polyphenols from cocoa and vascular health-a critical review.

PubMed

Rimbach, Gerald; Melchin, Mona; Moehring, Jennifer; Wagner, Anika E

2009-11-20

Cocoa is a rich source of dietary polyphenols. In vitro as well as cell culture data indicate that cocoa polyphenols may exhibit antioxidant and anti-inflammatory, as well as anti-atherogenic activity. Several molecular targets (e.g., nuclear factor kappa B, endothelial nitric oxide synthase, angiotensin converting enzyme) have been recently identified which may partly explain potential beneficial cardiovascular effects of cocoa polyphenols. However cocoa polyphenol concentrations, as used in many cell culture studies, are not physiologically achievable. Bioavailability studies indicate that plasma concentrations of cocoa polyphenols following dietary intake are low and in the nanomolar range. Human studies regarding the effect of cocoa polyphenols on vascular health are often underpowered and lack a rigorous study design. If dietary cocoa polyphenol intake is due to chocolate its high energy content needs to be taken into account. In order to determine potential health benefits of cocoa polyphenols large scale, long term, randomized, placebo controlled studies, (ideally with a cross-over design) as well as prospective studies are warranted.

Polyphenols from Cocoa and Vascular Health—A Critical Review

PubMed Central

Rimbach, Gerald; Melchin, Mona; Moehring, Jennifer; Wagner, Anika E.

2009-01-01

Cocoa is a rich source of dietary polyphenols. In vitro as well as cell culture data indicate that cocoa polyphenols may exhibit antioxidant and anti-inflammatory, as well as anti-atherogenic activity. Several molecular targets (e.g., nuclear factor kappa B, endothelial nitric oxide synthase, angiotensin converting enzyme) have been recently identified which may partly explain potential beneficial cardiovascular effects of cocoa polyphenols. However cocoa polyphenol concentrations, as used in many cell culture studies, are not physiologically achievable. Bioavailability studies indicate that plasma concentrations of cocoa polyphenols following dietary intake are low and in the nanomolar range. Human studies regarding the effect of cocoa polyphenols on vascular health are often underpowered and lack a rigorous study design. If dietary cocoa polyphenol intake is due to chocolate its high energy content needs to be taken into account. In order to determine potential health benefits of cocoa polyphenols large scale, long term, randomized, placebo controlled studies, (ideally with a cross-over design) as well as prospective studies are warranted. PMID:20057946

Potential sources of precipitation in Lake Baikal basin

NASA Astrophysics Data System (ADS)

Shukurov, K. A.; Mokhov, I. I.

2017-11-01

Based on the data of long-term measurements at 23 meteorological stations in the Russian part of the Lake Baikal basin the probabilities of daily precipitation with different intensity and their contribution to the total precipitation are estimated. Using the trajectory model HYSPLIT_4 for each meteorological station for the period 1948-2016 the 10-day backward trajectories of air parcels, the height of these trajectories and distribution of specific humidity along the trajectories are calculated. The average field of power of potential sources of daily precipitation (less than 10 mm) for all meteorological stations in the Russian part of the Lake Baikal basin was obtained using the CWT (concentration weighted trajectory) method. The areas have been identified from which within 10 days water vapor can be transported to the Lake Baikal basin, as well as regions of the most and least powerful potential sources. The fields of the mean height of air parcels trajectories and the mean specific humidity along the trajectories are compared with the field of mean power of potential sources.

Long-term monitoring of persistent organic pollutants (POPs) at the Norwegian Troll station in Dronning Maud Land, Antarctica

NASA Astrophysics Data System (ADS)

Kallenborn, R.; Breivik, K.; Eckhardt, S.; Lunder, C. R.; Manø, S.; Schlabach, M.; Stohl, A.

2013-07-01

A first long-term monitoring of selected persistent organic pollutants (POPs) in Antarctic air has been conducted at the Norwegian research station Troll (Dronning Maud Land). As target contaminants 32 PCB congeners, α- and γ-hexachlorocyclohexane (HCH), trans- and cis-chlordane, trans- and cis-nonachlor, p,p'- and o,p-DDT, DDD, DDE as well as hexachlorobenzene (HCB) were selected. The monitoring program with weekly samples taken during the period 2007-2010 was coordinated with the parallel program at the Norwegian Arctic monitoring site (Zeppelin mountain, Ny-Ålesund, Svalbard) in terms of priority compounds, sampling schedule as well as analytical methods. The POP concentration levels found in Antarctica were considerably lower than Arctic atmospheric background concentrations. Similar to observations for Arctic samples, HCB is the predominant POP compound, with levels of around 22 pg m-3 throughout the entire monitoring period. In general, the following concentration distribution was found for the Troll samples analyzed: HCB > Sum HCH > Sum PCB > Sum DDT > Sum chlordanes. Atmospheric long-range transport was identified as a major contamination source for POPs in Antarctic environments. Several long-range transport events with elevated levels of pesticides and/or compounds with industrial sources were identified based on retroplume calculations with a Lagrangian particle dispersion model (FLEXPART).

Demographic stability metrics for conservation prioritization of isolated populations.

PubMed

Finn, Debra S; Bogan, Michael T; Lytle, David A

2009-10-01

Systems of geographically isolated habitat patches house species that occur naturally as small, disjunct populations. Many of these species are of conservation concern, particularly under the interacting influences of isolation and rapid global change. One potential conservation strategy is to prioritize the populations most likely to persist through change and act as sources for future recolonization of less stable localities. We propose an approach to classify long-term population stability (and, presumably, future persistence potential) with composite demographic metrics derived from standard population-genetic data. Stability metrics can be related to simple habitat measures for a straightforward method of classifying localities to inform conservation management. We tested these ideas in a system of isolated desert headwater streams with mitochondrial sequence data from 16 populations of a flightless aquatic insect. Populations exhibited a wide range of stability scores, which were significantly predicted by dry-season aquatic habitat size. This preliminary test suggests strong potential for our proposed method of classifying isolated populations according to persistence potential. The approach is complementary to existing methods for prioritizing local habitats according to diversity patterns and should be tested further in other systems and with additional loci to inform composite demographic stability scores.

Acoustic/infrasonic rocket engine signatures

NASA Astrophysics Data System (ADS)

Tenney, Stephen M.; Noble, John M.; Whitaker, Rodney W.; ReVelle, Douglas O.

2003-09-01

Infrasonics offers the potential of long-range acoustic detection of explosions, missiles and even sounds created by manufacturing plants. The atmosphere attenuates acoustic energy above 20 Hz quite rapidly, but signals below 10 Hz can propagate to long ranges. Space shuttle launches have been detected infrasonically from over 1000 km away and the Concorde airliner from over 400 km. This technology is based on microphones designed to respond to frequencies from .1 to 300 Hz that can be operated outdoors for extended periods of time with out degrading their performance. The US Army Research Laboratory and Los Alamos National Laboratory have collected acoustic and infrasonic signatures of static engine testing of two missiles. Signatures were collected of a SCUD missile engine at Huntsville, AL and a Minuteman engine at Edwards AFB. The engines were fixed vertically in a test stand during the burn. We will show the typical time waveform signals of these static tests and spectrograms for each type. High resolution, 24-bit data were collected at 512 Hz and 16-bit acoustic data at 10 kHz. Edwards data were recorded at 250 Hz and 50 Hz using a Geotech Instruments 24 bit digitizer. Ranges from the test stand varied from 1 km to 5 km. Low level and upper level meteorological data was collected to provide full details of atmospheric propagation during the engine test. Infrasonic measurements were made with the Chaparral Physics Model 2 microphone with porous garden hose attached for wind noise suppression. A B&K microphone was used for high frequency acoustic measurements. Results show primarily a broadband signal with distinct initiation and completion points. There appear to be features present in the signals that would allow identification of missile type. At 5 km the acoustic/infrasonic signal was clearly present. Detection ranges for the types of missile signatures measured will be predicted based on atmospheric modeling. As part of an experiment conducted by ARL, sounding rocket launches have been detected from over 150 km. A variety of rockets launched from NASA"s Wallops Island facility were detected over a two year span. Arrays of microphones were able to create a line of bearing to the source of the launches that took place during different times of the year. This same experiment has been able to detect the space shuttle from over 1000 km on a regular basis. These two sources represent opposite ends of the target size, but they do demonstrate the potential for the detection and location of rocket launches.

MAXI observations of long X-ray bursts

NASA Astrophysics Data System (ADS)

Serino, Motoko; Iwakiri, Wataru; Tamagawa, Toru; Sakamoto, Takanori; Nakahira, Satoshi; Matsuoka, Masaru; Yamaoka, Kazutaka; Negoro, Hitoshi

2016-12-01

We report nine long X-ray bursts from neutron stars, detected with the Monitor of All-sky X-ray Image (MAXI). Some of these bursts lasted for hours, and hence are qualified as superbursts, which are prolonged thermonuclear flashes on neutron stars and are relatively rare events. MAXI observes roughly 85% of the whole sky every 92 minutes in the 2-20 keV energy band, and has detected nine bursts with a long e-folding decay time, ranging from 0.27 to 5.2 hr, since its launch in 2009 August until 2015 August. The majority of the nine events were found to originate from transient X-ray sources. The persistent luminosities of the sources, when these prolonged bursts were observed, were lower than 1% of the Eddington luminosity for five of them and lower than 20% for the rest. This trend is contrastive to the 18 superbursts observed before MAXI, all but two of which originated from bright persistent sources. The distribution of the total emitted energy, i.e., the product of e-folding time and luminosity, of these bursts clusters around 1041-1042 erg, whereas both the e-folding time and luminosity ranges for an order of magnitude. Among the nine events, two were from 4U 1850-086 during phases of relatively low persistent flux, whereas it usually exhibits standard short X-ray bursts during outbursts.

Hydrologic influences of forest vegetation in a changing world: Learning from Forest Service experimental forests, ranges, and watersheds

Treesearch

Thomas E. Lisle; Mary Beth Adams; Leslie M. Reid; Kelly Elder

2010-01-01

The importance of forests in providing reliable sources of clean water cannot be underestimated. Therefore, there is a pressing need to understand how hydrologic systems function in forested ecosystems, in response to a variety of traditional and novel stressors and environments. Long-term watershed research on Experimental Forests and Ranges (EFRs) of the Forest...

Exploring the Effect of Media, Salinity and Clay on the Thermoelectric Coupling Coefficient in Self-Potential Data

NASA Astrophysics Data System (ADS)

Meyer, C. D.; Revil, A.

2014-12-01

Self-potential is a non-invasive, passive geophysical technique with applications ranging from imaging oil and gas reservoirs to identifying preferential flow paths in earthen embankments. Several cross-coupled flow phenomena contribute to self-potential data, and there is a need to further quantify these various sources to enable better resolution and quantification of self-potential models. Very little research has been done to constrain thermoelectric source mechanisms that contribute to self-potential signals. A laboratory experiment has been designed to investigate the thermoelectric coupling coefficient (CTE) that relates the voltage change per degree centigrade (V/°C) in porous media. This study focuses on a sand tank experiment using a saturated silica sand. To isolate the temperature gradient dependence of self-potential measurements, no hydraulic gradient is applied to the tank, eliminating the streaming potential component of source current. Self-potential and temperature data are recorded while reservoirs of hot and cold water are established on opposite ends of the tank in order to generate thermoelectric source currents. Various thermal gradients ranging from 0 °C to 80 °C over 20 cm are examined for various salinities (10-3M- 1M NaCl), sand grain sizes and clay content to investigate influences on CTE. A short-duration contact of non-polarizing (Pb/PbCl) electrodes is implemented to minimize temperature drift of electrodes during the experiment. Surface self-potential and temperature measurements are made in 30 minute intervals. Initial measurements have revealed non-linear effects, including a decreased CTE as temperature gradient bounds approach 0 °C.

Fiber-coupled pillar array as a highly pure and stable single-photon source

NASA Astrophysics Data System (ADS)

Odashima, S.; Sasakura, H.; Nakajima, H.; Kumano, H.

2017-12-01

A highly pure and stable single-photon source is prepared that comprises a well-designed pillar array, in which each pillar contains only a few InAs quantum dots. A nano-pillar in this array is in direct contact with a fiber end surface and cooled in a liquid-He bath. Auto-correlation measurements show that this source provides an average g(2)(0) value of 0.0174 in the measured excitation-power range. This photon source and fiber coupling are quite rigid against external disturbances such as cooling-heating cycles and vibration, with long-term stability.

Effective potentials for H2O-He and H2O-Ar systems. Isotropic induction-dispersion potentials

NASA Astrophysics Data System (ADS)

Starikov, Vitali I.; Petrova, Tatiana M.; Solodov, Alexander M.; Solodov, Alexander A.; Deichuli, Vladimir M.

2017-05-01

The vibrational and rotational dependence of the effective isotropic interaction potential of H2O-He and H2O-Ar systems, taken in the form of Lennard-Jones 6-12 potential has been analyzed. The analysis is based on the experimental line broadening (γ) and line shift (δ) coefficients obtained for different vibrational bands of H2O molecule perturbed by He and Ar. The first and second derivatives of the function C(1)(q) for the long-range part of the induction-dispersion potential with respect to the dimensionless normal coordinates q were calculated using literature information for the dipole moment and mean polarizability functions μ(q) and α(q), respectively. These derivatives have been used in the calculations of the quantities which determine the vibrational and rotational dependence of the long-range part of the effective isotropic potential. The optimal set of the derivatives for the function C(1)(q) is proposed. The comparison with the experimental data has been performed.

Potential Overwintering Locations of Soybean Aphid (Hemiptera: Aphididae) Colonizing Soybean in Ohio and Wisconsin.

PubMed

Crossley, Michael S; Hogg, David B

2015-04-01

Soybean aphids, Aphis glycines Matsumura, depend on long-distance, wind-aided dispersal to complete their life cycle. Despite our general understanding of soybean aphid biology, little is explicitly known about dispersal of soybean aphids between winter and summer hosts in North America. This study compared genotypic diversity of soybean aphids sampled from several overwintering locations in the Midwest and soybean fields in Ohio and Wisconsin to test the hypothesis that these overwintering locations are sources of the soybean colonists. In addition, air parcel trajectory analyses were used to demonstrate the potential for long-distance dispersal events to occur to or from these overwintering locations. Results suggest that soybean aphids from overwintering locations along the Illinois-Iowa border and northern Indiana-Ohio are potential colonists of soybean in Ohio and Wisconsin, but that Ohio is also colonized by soybean aphids from other unknown overwintering locations. Soybean aphids in Ohio and Wisconsin exhibit a small degree of population structure that is not associated with the locations of soybean fields in which they occur, but that may be related to specific overwintering environments, multiple introductions to North America, or spatial variation in aphid phenology. There may be a limited range of suitable habitat for soybean aphid overwintering, in which case management of soybean aphids may be more effective at their overwintering sites. Further research efforts should focus on discovering more overwintering locations of soybean aphid in North America, and the relative impact of short- and long-distance dispersal events on soybean aphid population dynamics. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Integrating multiple remote sensing and surface measurements with models, to quantify and constrain the past decade's total 4D aerosol source profile and impacts

NASA Astrophysics Data System (ADS)

Cohen, J. B.; Lan, R.; Lin, C.; Ng, D. H. L.; Lim, A.

2017-12-01

A multi-instrument, inverse modeling approach, is employed to identify and quantify large-scale global biomass urban aerosol emissions profiles. The approach uses MISR, MODIS, OMI and MOPITT, with data from 2006 to 2016, to generate spatial and temporal loads, as well as some information about composition. The method is able to identify regions impacted by stable urban sources, changing urban sources, intense fires, and linear-combinations. Subsequent quantification is a unified field, leading to a less biased profile, with the result not requiring arbitrary scaling to match long-term means. Additionally, the result reasonably reproduces inter and intra annual variation. Both meso-scale (WRF-CHEM) and global (MIT-AERO, multi-mode, multi-mixing state aerosol model) models of aerosol transport, chemistry, and physics, are used to generate resulting 4D aerosol fields. Comparisons with CALIOP, AERONET, and surface chemical and aerosol networks, provide unbiased confirmation, while column and vertical loadings provide additional feedback. There are three significant results. First, there is a reduction in sources over existing urban areas in East Asia. Second, there is an increase in sources over new urban areas in South, South East, and East Asia. Third, that there is an increase in fire sources in South and South East Asia. There are other initial findings relevant to the global tropics, which have not been as deeply investigated. The results improve the model match with both the mean and variation, which is essential if we hope to understand seasonal extremes. The results also quantify impacts of both local and long-range sources. This is of extreme urgency, in particular in developing nations, where there are considerable contributions from long-range or otherwise unknown sources, that impact hundreds of millions of people throughout Asia. It is hoped that the approach provided here can help us to make critical decisions about total sources, as well as point out the many missing scientific and analytical issues still required to address.

Source apportionment of PM10 and PM2.5 in major urban Greek agglomerations using a hybrid source-receptor modeling process.

PubMed

Argyropoulos, G; Samara, C; Diapouli, E; Eleftheriadis, K; Papaoikonomou, K; Kungolos, A

2017-12-01

A hybrid source-receptor modeling process was assembled, to apportion and infer source locations of PM 10 and PM 2.5 in three heavily-impacted urban areas of Greece, during the warm period of 2011, and the cold period of 2012. The assembled process involved application of an advanced computational procedure, the so-called Robotic Chemical Mass Balance (RCMB) model. Source locations were inferred using two well-established probability functions: (a) the Conditional Probability Function (CPF), to correlate the output of RCMB with local wind directional data, and (b) the Potential Source Contribution Function (PSCF), to correlate the output of RCMB with 72h air-mass back-trajectories, arriving at the receptor sites, during sampling. Regarding CPF, a higher-level conditional probability function was defined as well, from the common locus of CPF sectors derived for neighboring receptor sites. With respect to PSCF, a non-parametric bootstrapping method was applied to discriminate the statistically significant values. RCMB modeling showed that resuspended dust is actually one of the main barriers for attaining the European Union (EU) limit values in Mediterranean urban agglomerations, where the drier climate favors build-up. The shift in the energy mix of Greece (caused by the economic recession) was also evidenced, since biomass burning was found to contribute more significantly to the sampling sites belonging to the coldest climatic zone, particularly during the cold period. The CPF analysis showed that short-range transport of anthropogenic emissions from urban traffic to urban background sites was very likely to have occurred, within all the examined urban agglomerations. The PSCF analysis confirmed that long-range transport of primary and/or secondary aerosols may indeed be possible, even from distances over 1000km away from study areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Acoustic characteristics of ultrasonic coded transmitters for fishery applications: could marine mammals hear them?

PubMed

Bowles, Ann E; Denes, Samuel L; Shane, Michael A

2010-11-01

Ultrasonic coded transmitters (UCTs) producing frequencies of 69-83 kHz are used increasingly to track fish and invertebrates in coastal and estuarine waters. To address concerns that they might be audible to marine mammals, acoustic properties of UCTs were measured off Mission Beach, San Diego, and at the U.S. Navy TRANSDEC facility. A regression model fitted to VEMCO UCT data yielded an estimated source level of 147 dB re 1 μPa SPL @ 1 m and spreading constant of 14.0. Based on TRANSDEC measurements, five VEMCO 69 kHz UCTs had source levels ranging from 146 to 149 dB re 1 μPa SPL @ 1 m. Five Sonotronics UCTs (69 kHz and 83 kHz) had source levels ranging from 129 to 137 dB re 1 μPa SPL @ 1 m. Transmitter directionality ranged from 3.9 to 18.2 dB. Based on propagation models and published data on marine mammal auditory psychophysics, harbor seals potentially could detect the VEMCO 69 kHz UCTs at ranges between 19 and >200 m, while odontocetes potentially could detect them at much greater ranges. California sea lions were not expected to detect any of the tested UCTs at useful ranges.

Dynamic Simulation of Random Packing of Polydispersive Fine Particles

NASA Astrophysics Data System (ADS)

Ferraz, Carlos Handrey Araujo; Marques, Samuel Apolinário

2018-02-01

In this paper, we perform molecular dynamic (MD) simulations to study the two-dimensional packing process of both monosized and random size particles with radii ranging from 1.0 to 7.0 μm. The initial positions as well as the radii of five thousand fine particles were defined inside a rectangular box by using a random number generator. Both the translational and rotational movements of each particle were considered in the simulations. In order to deal with interacting fine particles, we take into account both the contact forces and the long-range dispersive forces. We account for normal and static/sliding tangential friction forces between particles and between particle and wall by means of a linear model approach, while the long-range dispersive forces are computed by using a Lennard-Jones-like potential. The packing processes were studied assuming different long-range interaction strengths. We carry out statistical calculations of the different quantities studied such as packing density, mean coordination number, kinetic energy, and radial distribution function as the system evolves over time. We find that the long-range dispersive forces can strongly influence the packing process dynamics as they might form large particle clusters, depending on the intensity of the long-range interaction strength.

High methane emissions dominated annual greenhouse gas balances 30 years after bog rewetting

NASA Astrophysics Data System (ADS)

Vanselow-Algan, M.; Schmidt, S. R.; Greven, M.; Fiencke, C.; Kutzbach, L.; Pfeiffer, E.-M.

2015-07-01

Natural peatlands are important carbon sinks and sources of methane (CH4). In contrast, drained peatlands turn from a carbon sink to a carbon source and potentially emit nitrous oxide (N2O). Rewetting of peatlands thus potentially implies climate change mitigation. However, data about the time span that is needed for the re-establishment of the carbon sink function by restoration are scarce. We therefore investigated the annual greenhouse gas (GHG) balances of three differently vegetated sites of a bog ecosystem 30 years after rewetting. All three vegetation communities turned out to be sources of carbon dioxide (CO2) ranging between 0.6 ± 1.43 t CO2 ha-2 yr-1 (Sphagnum-dominated vegetation) and 3.09 ± 3.86 t CO2 ha-2 yr-1 (vegetation dominated by heath). While accounting for the different global warming potential (GWP) of CO2, CH4 and N2O, the annual GHG balance was calculated. Emissions ranged between 25 and 53 t CO2-eq ha-1 yr-1 and were dominated by large emissions of CH4 (22-51 t CO2-eq ha-1 yr-1), with highest rates found at purple moor grass (Molinia caerulea) stands. These are to our knowledge the highest CH4 emissions so far reported for bog ecosystems in temperate Europe. As the restored area was subject to large fluctuations in the water table, we assume that the high CH4 emission rates were caused by a combination of both the temporal inundation of the easily decomposable plant litter of purple moor grass and the plant-mediated transport through its tissues. In addition, as a result of the land use history, mixed soil material due to peat extraction and refilling can serve as an explanation. With regards to the long time span passed since rewetting, we note that the initial increase in CH4 emissions due to rewetting as described in the literature is not inevitably limited to a short-term period.

Predicting long-range transport: a systematic evaluation of two multimedia transport models.

PubMed

Bennett, D H; Scheringer, M; McKone, T E; Hungerbühler, K

2001-03-15

The United Nations Environment Program has recently developed criteria to identify and restrict chemicals with a potential for persistence and long-range transport (persistent organic pollutants or POPs). There are many stakeholders involved, and the issues are not only scientific but also include social, economic, and political factors. This work focuses on one aspect of the POPs debate, the criteria for determining the potential for long-range transport (LRT). Our goal is to determine if current models are reliable enough to support decisions that classify a chemical based on the LRT potential. We examine the robustness of two multimedia fate models for determining the relative ranking and absolute spatial range of various chemicals in the environment. We also consider the effect of parameter uncertainties and the model uncertainty associated with the selection of an algorithm for gas-particle partitioning on the model results. Given the same chemical properties, both models give virtually the same ranking. However, when chemical parameter uncertainties and model uncertainties such as particle partitioning are considered, the spatial range distributions obtained for the individual chemicals overlap, preventing a distinct rank order. The absolute values obtained for the predicted spatial range or travel distance differ significantly between the two models for the uncertainties evaluated. We find that to evaluate a chemical when large and unresolved uncertainties exist, it is more informative to use two or more models and include multiple types of uncertainty. Model differences and uncertainties must be explicitly confronted to determine how the limitations of scientific knowledge impact predictions in the decision-making process.

The potential for effluent trading in the energy industries.

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

Veil, J. A.; Environmental Assessment

1998-01-01

In January 1996, the US Environmental Protection Agency (EPA) released a policy statement endorsing wastewater effluent trading in watersheds, hoping to promote additional interest in the subject. The policy describes five types of effluent trades: point source/point source, point source/nonpoint source, pretreatment, intraplant and nonpoint source/nonpoint source. This paper evaluates the feasibility of implementing these types of effluent trading for facilities in the oil and gas, electric power and coal industries. This paper finds that the potential for effluent trading in these industries is limited because trades would generally need to involve toxic pollutants, which can only be traded undermore » a narrow range of circumstances. However, good potential exists for other types of water-related trades that do not directly involve effluents (e.g. wetlands mitigation banking and voluntary environmental projects). The potential for effluent trading in the energy industries and in other sectors would be enhanced if Congress amended the Clean Water Act (CWA) to formally authorize such trading.« less

The B 1Πu potential energy curve and dissociation energy of 39K2

NASA Astrophysics Data System (ADS)

Heinze, Johannes; Engelke, Friedrich

1988-07-01

The 39K2 B 1Πu potential energy curve has been determined using laser spectroscopic techniques and quantum mechanical calculations. The dissociation energy is 2407.6±0.5 cm-1 (0.2985±0.0001 eV) including a potential barrier of 298±10 cm-1 (0.037±0.0013 eV) found with its maximum at 8.08±0.05 Å (15.3±0.1 bohr). The long-range behavior matches smoothly onto the form predicted from dispersion forces. The dissociation energy of the ground state X 1Σ+g, obtained by a long-range extrapolation of the vibrational separations, is De =4444±10 cm-1 (0.5506±0.0013 eV), in agreement with recent theoretical prediction.

Soluble and insoluble carbon content in fog: a 16 year long study in the Po Valley (Italy)

NASA Astrophysics Data System (ADS)

Fuzzi, S.; Facchini, C.; Giulianelli, L.; Gilardoni, S.

2015-12-01

Fog samples have been collected throughout the fall-winter season during each dense fog episode since 1989 at the field station of San Pietro Capofiume (Bologna, Italy) located in a rural area in the south-eastern part of the Po Valley. Since the fall-winter season 1997/98 both soluble and insoluble carbon content was also measured and now a sixteen years long dataset is available. Carbonaceous matter accounts for a significant fraction of the insoluble material suspended in fog water. The sum of EC and water insoluble organic mass accounts on average for 46%-56% of the mass of total suspended material. Insoluble carbonaceous material is composed mainly by organic matter, EC accounting on average only for 17% of the total insoluble carbon. A good correlation observed between EC and OC through the different years, suggests that anthropogenic combustion processes, which represent the main source of EC, are also the most important source of OC in fog droplets. Recent results also show that a potential important contribution to WSOC in for water is derived by aqueous secondary organic aerosol from biomass burning emissions. The water soluble organic carbon (WSOC) represents on average 25% of the total solute mass and its contribution to the total organic carbon (TOC) ranges from 52 to 95% with an average of 86%. The high amount of carbonaceous compounds in the Po Valley fog detected and the simultaneous decrease of the main inorganic species concentration (Giulianelli et al., 2014) in the last two decades highlight the potential influence of organics on the decrease of fog frequency. Giulianelli L., Gilardoni S., Tarozzi L., Rinaldi M., Decesari S, Carbone C., Facchini M.C. and Fuzzi S., Atmos. Environ. 98, 394-401.

Gravitational Wave Astronomy:The High Frequency Window

NASA Astrophysics Data System (ADS)

Andersson, Nils; Kokkotas, Kostas D.

As several large scale interferometers are beginning to take data at sensitivities where astrophysical sources are predicted, the direct detection of gravitational waves may well be imminent. This would (finally) open the long anticipated gravitational-wave window to our Universe, and should lead to a much improved understanding of the most violent processes imaginable; the formation of black holes and neutron stars following core collapse supernovae and the merger of compact objects at the end of binary inspiral. Over the next decade we can hope to learn much about the extreme physics associated with, in particular, neutron stars. This contribution is divided in two parts. The first part provides a text-book level introduction to gravitational radiation. The key concepts required for a discussion of gravitational-wave physics are introduced. In particular, the quadrupole formula is applied to the anticipated bread-and-butter source for detectors like LIGO, GEO600, EGO and TAMA300: inspiralling compact binaries. The second part provides a brief review of high frequency gravitational waves. In the frequency range above (say) 100 Hz, gravitational collapse, rotational instabilities and oscillations of the remnant compact objects are potentially important sources of gravitational waves. Significant and unique information concerning the various stages of collapse, the evolution of protoneutron stars and the details of the supranuclear equation of state of such objects can be drawn from careful study of the gravitational-wave signal. As the amount of exciting physics one may be able to study via the detections of gravitational waves from these sources is truly inspiring, there is strong motivation for the development of future generations of ground based detectors sensitive in the range from hundreds of Hz to several kHz.

From source to sink: Rare-earth elements trace the legacy of sulfuric dredge spoils on estuarine sediments.

PubMed

Xu, Nian; Morgan, Bree; Rate, Andrew W

2018-05-17

Land disposal of dredged sulfide-rich coastal sediments generates secondary coastal acid sulfate soils (CASS), as previously reduced sulfide minerals oxidise to produce acidic drainage rich in Fe, SO 4 2- and rare-earth elements (REEs). Few studies investigate both the source and the sink of REEs in the context of interpreting their mobilisation and potential use in tracing anthropogenic activity. Here we investigate REE signatures in estuarine sediments (and overlying surface waters) that have received acute, long-term (>15 years) acidic drainage from legacy sulfuric dredge spoils. It was found that the dredge spoil continues to act as a source of acidity (pH 3.5-5.5), Fe and REEs during development of CASS, and contains negligible acid volatile sulfide (AVS, a proxy for FeS) and relatively low concentrations of ΣREE (mean 44.5 mg/kg, range 4.1-362 mg/kg). In the receiving sediments, high AVS concentrations (mean 92.2 μmol/g, range 0.38-278 μmol/g) reflect elevated FeS content, likely due to high inputs of Fe and SO 4 2- from the acidic drainage, and correspond with a high concentration of total S (mean 852 μmol/g, range 105-2209 μmol/g) and an accumulation of ΣREE (mean 670 mg/kg, range 19.9-1819 mg/kg). Importantly, where drain sediments that were previously enriched in highly reactive sulfidic minerals and trace elements and have become exposed to the atmosphere (e.g. Site 3) and partially oxidised, they provide a further source of acidification, remobilising the REEs to the downstream sediments. Interestingly, we also found a clear positive correlation between phosphorous and REEs both in the dredge spoil and sediment, suggesting phosphate minerals may act as a sink for REEs in CASS influenced drain sediments. This is further supported by strong positive gadolinium anomalies (1.1-1.6) and high calculated anthropogenic Gd values (12-38%), which may reflect the influence of phosphate fertiliser on this eutrophic system. Copyright © 2018 Elsevier B.V. All rights reserved.

Nationwide Distribution of Per- and Polyfluoroalkyl Substances in Outdoor Dust in Mainland China From Eastern to Western Areas.

PubMed

Yao, Yiming; Sun, Hongwen; Gan, Zhiwei; Hu, Hongwei; Zhao, Yangyang; Chang, Shuai; Zhou, Qixing

2016-04-05

From eastern to western areas, per- and polyfluoroalkyl substances (PFASs) were detected at substantial levels in the outdoor dust across mainland China. Urban samples generally showed higher levels compared with those of rural samples. Compared with neutral PFASs, ionizable PFASs (C4-C12 perfluoroalkyl carboxylic acids and C4/C8 perfluoroalkyl sulfonic acids) were more abundant, with the highest total concentration up to 1.6 × 10(2) ng/g and perfluorooctanoic acid (PFOA) being a predominant analogue. Fluorotelomer alcohols (FTOHs) and polyfluoroalkyl phosphoric acid diesters (DiPAPs) were both detected in most samples with total concentrations of 0.12-32 and 0.030-20 ng/g, respectively. Perfluorooctane sulfonamidoethanols/sulfonamides (FOSE/As) were detected at low frequencies (<30%). In addition to partitioning to organic moiety, specific adsorption onto mineral particles can be important for PFASs to bind onto outdoor dust, especially for short-chain ionizable PFASs. The eastern plain areas were characterized by a higher contribution of long-chain ionizable PFASs; whereas the western high plateau areas were characterized by the dominating contribution of short-chain analogues. The difference suggests that the long-range atmospheric transport potential of PFASs from source regions to the inland is probably limited by the increase in altitude, and different sources from adjacent regions may influence the western border area of China.

All-periodically poled, high-power, continuous-wave, single-frequency tunable UV source.

PubMed

Aadhi, A; Chaitanya N, Apurv; Jabir, M V; Singh, R P; Samanta, G K

2015-01-01

We report on experimental demonstration of an all-periodically poled, continuous-wave (CW), high-power, single-frequency, ultra-violet (UV) source. Based on internal second-harmonic-generation (SHG) of a CW singly resonant optical parametric oscillator (OPO) pumped in the green, the UV source provides tunable radiation across 398.94-417.08 nm. The compact source comprising of a 25-mm-long MgO-doped periodically poled stoichiometric lithium tantalate (MgO:sPPLT) crystal of period Λ(SLT)=8.5  μm for OPO and a 5-mm-long, multi-grating (Λ(KTP)=3.3, 3.4, 3.6 and 3.8 μm), periodically poled potassium titanium phosphate (PPKTP) for intra-cavity SHG, provides as much as 336 mW of UV power at 398.94 nm, corresponding to a green-to-UV conversion efficiency of ∼6.7%. In addition, the singly resonant OPO (SRO) provides 840 mW of idler at 1541.61 nm and substantial signal power of 108 mW at 812.33 nm transmitted through the high reflective cavity mirrors. UV source provides single-frequency radiation with instantaneous line-width of ∼18.3  MHz and power >100  mW in Gaussian beam profile (ellipticity >92%) across the entire tuning range. Access to lower UV wavelengths requires smaller grating periods to compensate high phase-mismatch resulting from high material dispersion in the UV wavelength range. Additionally, we have measured the normalized temperature and spectral acceptance bandwidth of PPKTP crystal in the UV wavelength range to be ∼2.25°C·cm and ∼0.15  nm·cm, respectively.

Highly excited bound-state resonances of short-range inverse power-law potentials

NASA Astrophysics Data System (ADS)

Hod, Shahar

2017-11-01

We study analytically the radial Schrödinger equation with long-range attractive potentials whose asymptotic behaviors are dominated by inverse power-law tails of the form V(r)=-β _n r^{-n} with n>2. In particular, assuming that the effective radial potential is characterized by a short-range infinitely repulsive core of radius R, we derive a compact analytical formula for the threshold energy E^{ {max}}_l=E^{ {max}}_l(n,β _n,R), which characterizes the most weakly bound-state resonance (the most excited energy level) of the quantum system.

Adiabatic description of long range frequency sweeping

NASA Astrophysics Data System (ADS)

Nyqvist, R. M.; Lilley, M. K.; Breizman, B. N.

2012-09-01

A theoretical framework is developed to describe long range frequency sweeping events in the 1D electrostatic bump-on-tail model with fast particle sources and collisions. The model includes three collision operators (Krook, drag (dynamical friction) and velocity space diffusion), and allows for a general shape of the fast particle distribution function. The behaviour of phase space holes and clumps is analysed in the absence of diffusion, and the effect of particle trapping due to separatrix expansion is discussed. With a fast particle distribution function whose slope decays above the resonant phase velocity, hooked frequency sweeping is found for holes in the presence of drag collisions alone.

Long-range surface plasmon polariton detection with a graphene photodetector.

PubMed

Ee, Ho-Seok; No, You-Shin; Kim, Jinhyung; Park, Hong-Gyu; Seo, Min-Kyo

2018-06-15

We present an integration of a single Ag nanowire (NW) with a graphene photodetector and demonstrate an efficient and compact detection of long-range surface plasmon polaritons (SPPs). Atomically thin graphene provides an ideal platform to detect the evanescent electric field of SPPs extremely bound at the interface of the Ag NW and glass substrate. Scanning photocurrent microscopy directly visualizes a polarization-dependent excitation and detects the SPPs. The SPP detection responsivity is readily controlled up to ∼17  mA/W by the drain-source voltage. We believe that the graphene SPP detector will be a promising building block for highly integrated photonic and optoelectronic circuits.

Long-range sound propagation: A review of some experimental data

NASA Technical Reports Server (NTRS)

Sutherland, Louis C.

1990-01-01

Three experimental studies of long range sound propagation carried out or sponsored in the past by NASA are briefly reviewed to provide a partial prospective for some of the analytical studies presented in this symposium. The three studies reviewed cover (1) a unique test of two large rocket engines conducted in such a way as to provide an indication of possible atmospheric scattering loss from a large low-frequency directive sound source, (2) a year-long measurement of low frequency sound propagation which clearly demonstrated the dominant influence of the vertical gradient in the vector sound velocity towards the receiver in defining excess sound attenuation due to refraction, and (3), a series of excess ground attenuation measurements over grass and asphalt surfaces replicated several times under very similar inversion weather conditions.

Source areas and long-range transport of pollen from continental land to Tenerife (Canary Islands).

PubMed

Izquierdo, Rebeca; Belmonte, Jordina; Avila, Anna; Alarcón, Marta; Cuevas, Emilio; Alonso-Pérez, Silvia

2011-01-01

The Canary Islands, due to their geographical position, constitute an adequate site for the study of long-range pollen transport from the surrounding land masses. In this study, we analyzed airborne pollen counts at two sites: Santa Cruz de Tenerife (SCO), at sea level corresponding to the marine boundary layer (MBL), and Izaña at 2,367 m.a.s.l. corresponding to the free troposphere (FT), for the years 2006 and 2007. We used three approaches to describe pollen transport: (1) a classification of provenances with an ANOVA test to describe pollen count differences between sectors; (2) a study of special events of high pollen concentrations, taking into consideration the corresponding meteorological synoptic pattern responsible for transport and back trajectories; and (3) a source-receptor model applied to a selection of the pollen taxa to show pollen source areas. Our results indicate several extra-regional pollen transport episodes to Tenerife. The main provenances were: (1) the Mediterranean region, especially the southern Iberian Peninsula and Morocco, through the trade winds in the MBL. These episodes were characterized by the presence of pollen from trees (Casuarina, Olea, Quercus perennial and deciduous types) mixed with pollen from herbs (Artemisia, Chenopodiaceae/Amaranthaceae and Poaceae wild type). (2) The Saharan sector, through transport at the MBL level carrying pollen principally from herbs (Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae wild type) and, in one case, Casuarina pollen, uplifted to the free troposphere. And (3) the Sahel, characterized by low pollen concentrations of Arecaceae, Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae wild type in sporadic episodes. This research shows that sporadic events of long-range pollen transport need to be taken into consideration in Tenerife as possible responsible agents in respiratory allergy episodes. In particular, it is estimated that 89-97% of annual counts of the highly allergenous Olea originates from extra-regional sources in southern Iberia and northern Africa.

Source areas and long-range transport of pollen from continental land to Tenerife (Canary Islands)

NASA Astrophysics Data System (ADS)

Izquierdo, Rebeca; Belmonte, Jordina; Avila, Anna; Alarcón, Marta; Cuevas, Emilio; Alonso-Pérez, Silvia

2011-01-01

The Canary Islands, due to their geographical position, constitute an adequate site for the study of long-range pollen transport from the surrounding land masses. In this study, we analyzed airborne pollen counts at two sites: Santa Cruz de Tenerife (SCO), at sea level corresponding to the marine boundary layer (MBL), and Izaña at 2,367 m.a.s.l. corresponding to the free troposphere (FT), for the years 2006 and 2007. We used three approaches to describe pollen transport: (1) a classification of provenances with an ANOVA test to describe pollen count differences between sectors; (2) a study of special events of high pollen concentrations, taking into consideration the corresponding meteorological synoptic pattern responsible for transport and back trajectories; and (3) a source-receptor model applied to a selection of the pollen taxa to show pollen source areas. Our results indicate several extra-regional pollen transport episodes to Tenerife. The main provenances were: (1) the Mediterranean region, especially the southern Iberian Peninsula and Morocco, through the trade winds in the MBL. These episodes were characterized by the presence of pollen from trees ( Casuarina, Olea, Quercus perennial and deciduous types) mixed with pollen from herbs ( Artemisia, Chenopodiaceae/Amaranthaceae and Poaceae wild type). (2) The Saharan sector, through transport at the MBL level carrying pollen principally from herbs (Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae wild type) and, in one case, Casuarina pollen, uplifted to the free troposphere. And (3) the Sahel, characterized by low pollen concentrations of Arecaceae, Chenopodiaceae-Amaranthaceae, Cyperaceae and Poaceae wild type in sporadic episodes. This research shows that sporadic events of long-range pollen transport need to be taken into consideration in Tenerife as possible responsible agents in respiratory allergy episodes. In particular, it is estimated that 89-97% of annual counts of the highly allergenous Olea originates from extra-regional sources in southern Iberia and northern Africa.

An Analytical Approach to Prioritizing the Development of Seabasing Components

DTIC Science & Technology

2007-04-05

high - speed ferries. The ships have served in intra-theater lift roles worldwide, as a staging platform for SOF during OIF, and as a ...testing. If Seabasing is to reach its full potential, a concerted effort needs to be made to develop a long-range, high - speed , heavy-lift cargo ...deck, high speed , containerized amphibious aircraft carriers) and aircraft (large, long range, naval airlift). A lot of money and energy will

An early deployment strategy for carbon capture, utilisation, and storage

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

Carter, L.D.

2012-11-01

This report describes the current use of CO2 for EOR, and discusses potential expansion of EOR using CO2 from power plants. Analysis of potential EOR development in the USA, where most current CO2-based EOR production takes place, indicates that relatively low cost, traditional sources of CO2 for EOR (CO2 domes and CO2 from natural gas processing plants) are insufficient to exploit the full potential of EOR. To achieve that full potential will require use of CO2 from combustion and gasification systems, such as fossil fuel power plants, where capture of CO2 is more costly. The cost of current CCUS systems,more » even with the revenue stream for sale of the CO2 for EOR, is too high to result in broad deployment of the technology in the near term. In the longer term, research and development may be sufficient to reduce CO2 capture costs to a point where CCUS would be broadly deployed. This report describes a case study of conditions in the USA to explore a financial incentive to promote early deployment of CCUS, providing a range of immediate benefits to society, greater likelihood of reducing the long-term cost of CCUS, and greater likelihood of broad deployment of CCUS and CCS in the long term. Additionally, it may be possible to craft such an incentive in a manner that its cost is more than offset by taxes flowing from increased domestic oil production. An example of such an incentive is included in this report.« less

Guidelines for the Design of GPS and LORAN Receiver Controls and Displays

DOT National Transportation Integrated Search

1995-03-01

Long range navigation (Loran) and global positioning system (GPS) receivers are widely used in aviation. The Loran and GPS receivers are similar in size and function but derive their navigation signals from different sources. The design of the contro...

Probing the role of long-range interactions in the dynamics of a long-range Kitaev chain

NASA Astrophysics Data System (ADS)

Dutta, Anirban; Dutta, Amit

2017-09-01

We study the role of long-range interactions (more precisely, the long-range superconducting gap term) on the nonequilibrium dynamics considering a long-range p -wave superconducting chain in which the superconducting term decays with distance between two sites in a power-law fashion characterized by an exponent α . We show that the Kibble-Zurek scaling exponent, dictating the power-law decay of the defect density in the final state reached following a slow (in comparison to the time scale associated with the minimum gap in the spectrum of the Hamiltonian) quenching of the chemical potential μ across a quantum critical point, depends nontrivially on the exponent α as long as α <2 ; on the other hand, for α >2 , we find that the exponent saturates to the corresponding well-known value of 1 /2 expected for the short-range model. Furthermore, studying the dynamical quantum phase transitions manifested in the nonanalyticities in the rate function of the return possibility I (t ) in subsequent temporal evolution following a sudden change in μ , we show the existence of a new region; in this region, we find three instants of cusp singularities in I (t ) associated with a single sector of Fisher zeros. Notably, the width of this region shrinks as α increases and vanishes in the limit α →2 , indicating that this special region is an artifact of the long-range nature of the Hamiltonian.

Concentrations of polycyclic aromatic hydrocarbons: Their potential health risks and sources at three non-urban sites in Japan.

PubMed

Jadoon, Waqar A; Sakugawa, Hiroshi

2016-09-18

This investigation was undertaken to monitor particulate polycyclic aromatic hydrocarbons (PAHs) concentrations in order to determine their emission sources and potential human health risks in remote and rural areas of Japan. Seventeen PAHs in aerosol samples collected in remote (Kamihaya), coastal (Hiki) and inland (Higashi-Hiroshima) areas of Japan during 2013-2014 were analyzed using gas chromatography/mass spectrometry. Total PAH (Σ17PAH) concentrations in aerosol samples were in the range of 0.08-6.51 ng m(-3), 0.09-4.74 ng m(-3), and 0.21-6.53 ng m(-3) at Kamihaya, Hiki, and Higashi-Hiroshima sites, with mean concentrations of 1.63, 1.18, and 2.43 ng m(-3), respectively. Significant seasonal variation in concentrations occurred at Hiki and Higashi-Hiroshima, while no significant variation occurred at Kamihaya. Ambient air temperature greatly affected PAH concentrations in Higashi-Hiroshima, but had only moderate effects in Kamihaya and Hiki. Wind direction also influenced the concentrations of PAHs. Vehicle exhaust, industrial emissions, biomass combustion, and domestic heating and cooking were identified as the main PAH emission sources using principal component analysis. Backward trajectory calculations showed that domestically generated PAHs were significant in Kamihaya and Hiki, while in Higashi-Hiroshima concentrations were mainly influenced by long-range transport. The incremental lifetime lung cancer risk had values of 3.38 × 10(-5) and 1.84 × 10(-5) at Higashi-Hiroshima and Hiki, which are greater than the US EPA acceptable level (10(-6)). Typically, 5-6-ring PAHs contributed 95% to this overall health risk, of which benzo(a)pyrene was the largest contributor, followed by dibenz(a,h)anthracene at both residential sites. Clearly, stricter guidelines for PAHs need to be implemented at these sites to protect the population.

High methane emissions dominate annual greenhouse gas balances 30 years after bog rewetting

NASA Astrophysics Data System (ADS)

Vanselow-Algan, M.; Schmidt, S. R.; Greven, M.; Fiencke, C.; Kutzbach, L.; Pfeiffer, E.-M.

2015-02-01

Natural peatlands are important carbon sinks and sources of methane (CH4). In contrast, drained peatlands turn from a carbon sink to a carbon source and potentially emit nitrous oxide (N2O). Rewetting of peatlands thus implies climate change mitigation. However, data about the time span that is needed for the re-establishment of the carbon sink function by restoration is scarce. We therefore investigated the annual greenhouse gas (GHG) balances of three differently vegetated bog sites 30 years after rewetting. All three vegetation communities turned out to be sources of carbon dioxide (CO2) ranging between 0.6 ± 1.43 t CO2 ha-2 yr-1 (Sphagnum-dominated vegetation) and 3.09 ± 3.86 t CO2 ha-2 yr-1 (vegetation dominated by heath). While accounting for the different global warming potential (GWP) of the three greenhouse gases, the annual GHG balance was calculated. Emissions ranged between 25 and 53 t CO2-eq ha-1 yr-1 and were dominated by large emissions of CH4 (22 up to 51 t CO2-eq ha-1 yr-1), while highest rates were found at purple moor grass (Molinia caerulea) stands. These are to our knowledge the highest CH4 emissions so far reported for bog ecosystems in temperate Europe. As the restored area was subject to large fluctuations in water table, we conclude that the high CH4 emission rates were caused by a combination of both the temporal inundation of the easily decomposable plant litter of this grass species and the plant-mediated transport through its tissues. In addition, as a result of the land use history, the mixed soil material can serve as an explanation. With regards to the long time span passed since rewetting, we note that the initial increase in CH4 emissions due to rewetting as described in the literature is not limited to a short-term period.

Alternative Sources of n-3 Long-Chain Polyunsaturated Fatty Acids in Marine Microalgae

PubMed Central

Martins, Dulce Alves; Custódio, Luísa; Barreira, Luísa; Pereira, Hugo; Ben-Hamadou, Radhouan; Varela, João; Abu-Salah, Khalid M.

2013-01-01

The main source of n-3 long-chain polyunsaturated fatty acids (LC-PUFA) in human nutrition is currently seafood, especially oily fish. Nonetheless, due to cultural or individual preferences, convenience, geographic location, or awareness of risks associated to fatty fish consumption, the intake of fatty fish is far from supplying the recommended dietary levels. The end result observed in most western countries is not only a low supply of n-3 LC-PUFA, but also an unbalance towards the intake of n-6 fatty acids, resulting mostly from the consumption of vegetable oils. Awareness of the benefits of LC-PUFA in human health has led to the use of fish oils as food supplements. However, there is a need to explore alternatives sources of LC-PUFA, especially those of microbial origin. Microalgae species with potential to accumulate lipids in high amounts and to present elevated levels of n-3 LC-PUFA are known in marine phytoplankton. This review focuses on sources of n-3 LC-PUFA, namely eicosapentaenoic and docosahexaenoic acids, in marine microalgae, as alternatives to fish oils. Based on current literature, examples of marketed products and potentially new species for commercial exploitation are presented. PMID:23807546

Long ranging swept-source optical coherence tomography-based angiography outperforms its spectral-domain counterpart in imaging human skin microcirculations

NASA Astrophysics Data System (ADS)

Xu, Jingjiang; Song, Shaozhen; Men, Shaojie; Wang, Ruikang K.

2017-11-01

There is an increasing demand for imaging tools in clinical dermatology that can perform in vivo wide-field morphological and functional examination from surface to deep tissue regions at various skin sites of the human body. The conventional spectral-domain optical coherence tomography-based angiography (SD-OCTA) system is difficult to meet these requirements due to its fundamental limitations of the sensitivity roll-off, imaging range as well as imaging speed. To mitigate these issues, we demonstrate a swept-source OCTA (SS-OCTA) system by employing a swept source based on a vertical cavity surface-emitting laser. A series of comparisons between SS-OCTA and SD-OCTA are conducted. Benefiting from the high system sensitivity, long imaging range, and superior roll-off performance, the SS-OCTA system is demonstrated with better performance in imaging human skin than the SD-OCTA system. We show that the SS-OCTA permits remarkable deep visualization of both structure and vasculature (up to ˜2 mm penetration) with wide field of view capability (up to 18×18 mm2), enabling a more comprehensive assessment of the morphological features as well as functional blood vessel networks from the superficial epidermal to deep dermal layers. It is expected that the advantages of the SS-OCTA system will provide a ground for clinical translation, benefiting the existing dermatological practice.

Continuous discharge Penning source with emission lines between 50 A and 300 A. [for astronomy

NASA Technical Reports Server (NTRS)

Finley, D. S.; Bowyer, S.; Paresce, F.; Malina, R. F.

1979-01-01

The present paper deals with a modified Penning discharge lamp developed specially to cover the soft X-ray and extreme UV spectral regions. The source produces a total of nearly 40 intense lines in the 50 to 300 A range. The lamp is quiet, continuous, and stable over most of the cathode lifetime (which is sufficient for long calibration runs). When the cathodes become exhausted, the refurbishment procedure is so simple that the source can be back on line in an hour or less

Single Neurons in the Avian Auditory Cortex Encode Individual Identity and Propagation Distance in Naturally Degraded Communication Calls.

PubMed

Mouterde, Solveig C; Elie, Julie E; Mathevon, Nicolas; Theunissen, Frédéric E

2017-03-29

One of the most complex tasks performed by sensory systems is "scene analysis": the interpretation of complex signals as behaviorally relevant objects. The study of this problem, universal to species and sensory modalities, is particularly challenging in audition, where sounds from various sources and localizations, degraded by propagation through the environment, sum to form a single acoustical signal. Here we investigated in a songbird model, the zebra finch, the neural substrate for ranging and identifying a single source. We relied on ecologically and behaviorally relevant stimuli, contact calls, to investigate the neural discrimination of individual vocal signature as well as sound source distance when calls have been degraded through propagation in a natural environment. Performing electrophysiological recordings in anesthetized birds, we found neurons in the auditory forebrain that discriminate individual vocal signatures despite long-range degradation, as well as neurons discriminating propagation distance, with varying degrees of multiplexing between both information types. Moreover, the neural discrimination performance of individual identity was not affected by propagation-induced degradation beyond what was induced by the decreased intensity. For the first time, neurons with distance-invariant identity discrimination properties as well as distance-discriminant neurons are revealed in the avian auditory cortex. Because these neurons were recorded in animals that had prior experience neither with the vocalizers of the stimuli nor with long-range propagation of calls, we suggest that this neural population is part of a general-purpose system for vocalizer discrimination and ranging. SIGNIFICANCE STATEMENT Understanding how the brain makes sense of the multitude of stimuli that it continually receives in natural conditions is a challenge for scientists. Here we provide a new understanding of how the auditory system extracts behaviorally relevant information, the vocalizer identity and its distance to the listener, from acoustic signals that have been degraded by long-range propagation in natural conditions. We show, for the first time, that single neurons, in the auditory cortex of zebra finches, are capable of discriminating the individual identity and sound source distance in conspecific communication calls. The discrimination of identity in propagated calls relies on a neural coding that is robust to intensity changes, signals' quality, and decreases in the signal-to-noise ratio. Copyright © 2017 Mouterde et al.

Improved Analytical Potentials for the a ^3Σu+ and X ^1Σg+ States of {Cs_2}

NASA Astrophysics Data System (ADS)

Baldwin, Jesse; Le Roy, Robert J.

2012-06-01

Recent studies of the collisional properties of ultracold Cs atoms have led to a renewed interest in the singlet and triplet ground-state potential energy functions of Cs_2. Coxon and Hajigeorgiou recently determined an analytic potential function for the X ^1Σ_g^+ state that accurately reproduces a large body of spectroscopic data that spanned 99.45% of the potential well. However, their potential explicitly incorporates only the three leading inverse-power terms in the long-range potential, and does not distinguish between the three asymptotes associated with the different Cs atom spin states. Similarly, Xie et al. have reported two versions of an analytic potential energy function for the a ^3Σ_u^+ state that they determined from direct potential fits to emission data that spanned 93 % of its potential energy well. However, the tail of their potential function model was not constrained to have the inverse-power-sum form required by theory. Moreover, a physically correct description of cold atom collision phenomena requires the long-range inverse-power tails of these two potentials to be identical, and they are not. Thus, these functions cannot be expected to describe cold atom collision properties correctly. The present paper describes our efforts to determine improved analytic potential energy functions for these states that have identical long-range tails, and fully represent all of the spectroscopic data used in the earlier worka,b,c as well as photoassociation data that was not considered there and experimental values of the collisional scattering lengths for the two states. J. A. Coxon and P. Hajigeorgiou, J. Chem. Phys. 132, 09105 (2010). F. Xie et al. J. Chem. Phys. 130 051102 (2009). F. Xie et al. J. Chem. Phys. 135, 024303 (2011) J. G. Danzl et al., Science, 321, 1062 (2008). C. Chin, et al., Phys. Rev. Lett. 85, 2717 (2000) P. J. Leo, C. J. Williams, and P. S. Julienne, Phys. Rev. Lett. 85, 2721 (2000)

Adult subventricular zone neural stem cells as a potential source of dopaminergic replacement neurons

PubMed Central

Cave, John W.; Wang, Meng; Baker, Harriet

2014-01-01

Clinical trials engrafting human fetal ventral mesencephalic tissue have demonstrated, in principle, that cell replacement therapy provides substantial long-lasting improvement of motor impairments generated by Parkinson's Disease (PD). The use of fetal tissue is not practical for widespread clinical implementation of this therapy, but stem cells are a promising alternative source for obtaining replacement cells. The ideal stem cell source has yet to be established and, in this review, we discuss the potential of neural stem cells in the adult subventricular zone (SVZ) as an autologous source of replacement cells. We identify three key challenges for further developing this potential source of replacement cells: (1) improving survival of transplanted cells, (2) suppressing glial progenitor proliferation and survival, and (3) developing methods to efficiently produce dopaminergic neurons. Subventricular neural stem cells naturally produce a dopaminergic interneuron phenotype that has an apparent lack of vulnerability to PD-mediated degeneration. We also discuss whether olfactory bulb dopaminergic neurons derived from adult SVZ neural stem cells are a suitable source for cell replacement strategies. PMID:24574954

Broadband near-field infrared spectroscopy with a high temperature plasma light source.

PubMed

Lahneman, D J; Huffman, T J; Xu, Peng; Wang, S L; Grogan, T; Qazilbash, M M

2017-08-21

Scattering-type scanning near-field optical microscopy (S-SNOM) has enormous potential as a spectroscopy tool in the infrared spectral range where it can probe phonon resonances and carrier dynamics at the nanometer lengths scales. However, its applicability is limited by the lack of practical and affordable table-top light sources emitting intense broadband infrared radiation in the 100 cm -1 to 2,500 cm -1 spectral range. This paper introduces a high temperature plasma light source that is both ultra-broadband and has much more radiant power in the infrared spectral range than conventional, table-top thermal light sources such as the globar. We implement this plasma lamp in our near-field optical spectroscopy set up and demonstrate its capability as a broadband infrared nano-spectroscopy light source by obtaining near-field infrared amplitude and phase spectra of the phonon resonances of SiO 2 and SrTiO 3 .

Distant and Regional Atmospheric Circulation Influences Governing Integrated Water Vapor Transport and the Occurrence of Extreme Precipitation Events

NASA Astrophysics Data System (ADS)

Bosart, L. F.; Papin, P. P.; Bentley, A. M.

2017-12-01

This presentation will show how the evolution of the large-scale and regional-scale atmospheric circulation contributes to the occurrence of extreme precipitation events (EPEs). An EPE requires that tropospheric moisture flux convergence (MFC) and the associated removal of hydrometeors be balanced by moisture replenishment via integrated (water) vapor transport (IVT) to continuously replenish condensed moisture. Moisture source regions may be distant or regional. Distant moisture sources may require the interaction of lower- and upper-level jet streams with a pre-existing mobile atmospheric disturbance to produce sufficient lift to condense moisture. Pre-existing regional moisture sources may require frontal lifting the presence of MFC to condense moisture. In cases of long-range IVT, such as moisture from a western North Pacific typhoon being drawn poleward along an atmospheric river (AR) toward the west coast of North America, moisture may be transported 1000s of kilometers along a low-level jet before a combination of dynamic and orographic lift results in an EPE. Alternatively, in the case of a typical summer warm and humid air mass over the continental United States, unused moisture may exist for several days in this air mass before sufficient MFC associated with a thermally direct mesoscale frontal circulation can concentrate and condense the moisture. In this case, there may be no long-range IVT via ARs. Instead, the atmospheric circulations may evolve to produce sustained MFC associated with mesoscale frontal circulations, especially in the presence of complex terrain, to produce an EPE. During this presentation, examples of EPEs associated with long-range IVT and distant MFC versus EPEs associated with regional MFC and mesoscale frontal circulations will be illustrated.

Demonstration of a long pulse X-ray source at the National Ignition Facility

NASA Astrophysics Data System (ADS)

May, M. J.; Opachich, Y. P.; Kemp, G. E.; Colvin, J. D.; Barrios, M. A.; Widmann, K. W.; Fournier, K. B.; Hohenberger, M.; Albert, F.; Regan, S. P.

2017-04-01

A long duration high fluence x-ray source has been developed at the National Ignition Facility (NIF). The target was a 14.4 mm tall, 4.1 mm diameter, epoxy walled, gas filled pipe. Approximately 1.34 MJ from the NIF laser was used to heat the mixture of (55:45) Kr:Xe at 1.2 atm (˜5.59 mg/cm3) to emit in a fairly isotropic radiant intensity of 400-600 GW/sr from the Ephoton = 3-7 keV spectral range for a duration of ≈ 14 ns. The HYDRA simulated radiant intensities were in reasonable agreement with experiments but deviated at late times.

Pollution data analysis and characteristics of volatile organic compounds in the environment

NASA Astrophysics Data System (ADS)

Wang, Qi; Wang, Chěn; Hou, Lujian; Lv, Bo; WANG, Chén

2018-06-01

Volatile organic compounds (VOCs) have a wide range of sources and have a significant impact on the ecological environment and human health, which have attracted wide attention of many researchers. In this paper, the pollution characteristics of VOCs, the role of VOCs in atmospheric chemistry including OH reaction reactivity (LOH), Ozone Formation Potential (OFP) and SOA generation potential (SOAP), VOCs source apportionment were discussed and reviewed.

Current and future contributions of local emissions from shipping and hydrocarbon extraction flaring to short lived pollutants in the Arctic

NASA Astrophysics Data System (ADS)

Marelle, L.; Raut, J. C.; Law, K.; Thomas, J. L.; Fast, J. D.; Berg, L. K.; Shrivastava, M. B.; Easter, R. C.; Herber, A. B.

2015-12-01

The Arctic is increasingly open to human activity due to rapid Arctic warming, associated with decreased sea ice extent and snow cover. While pollution from in-Arctic sources is currently low, oil and gas extraction and marine traffic could become a significant future source of short-lived pollutants (aerosols, ozone) in the Arctic. It is currently unclear if these local sources might become significant compared to the long-range transport of anthropogenic pollution from the midlatitudes, which is currently the main source of Arctic pollution. Here, we investigate the current (2012) and future (2050) impact of emissions from shipping and oil and gas extraction on Arctic aerosols and ozone, in relation to emissions from long-range transport. These impacts are determined by performing 6-month long, quasi-hemispheric simulations over the Arctic region with the WRF-Chem model. Our regional simulations include up-to-date representations of cloud/aerosol interactions and secondary organic aerosol formation developed recently for WRF-Chem. In order to determine the impact of Arctic shipping and oil and gas extraction, we use recent emission inventories by Winther et al., 2014 for local shipping and ECLIPSEv5 for oil and gas flaring. Both inventories suggest that current and future emissions from these sources are higher than previous estimates. Simulations are evaluated using measurements at Arctic surface sites and aircraft campaigns (ACCESS, YAK) in 2012. Model results are then used to assess the impact of Arctic shipping and oil and gas flaring on modeled surface aerosol and ozone concentrations, direct aerosol and ozone radiative effects, indirect aerosol radiative effects, and aerosol deposition. Results are used to determine if these local emissions are expected to have a significant influence on these quantities at the local or the regional scale, compared to emissions transported from the midlatitudes and to other emission sources, including boreal fires.

An Approach to Modeling the Water Balance Sensitivity to Landscape Vegetation Changes

NASA Astrophysics Data System (ADS)

Mohammed, I. N.; Tarboton, D. G.

2008-12-01

Watershed development and management require an understanding of how hydrological processes affect water balance components. The study of water resources management, especially in Western United States, is currently motivated by climate change, the impact of vegetation cover change on water production, and the need to manage water supplies. Vegetation management and its relation to runoff has been well documented, as reduction of forest cover, reducing evapotranspiration, increases water yield and in contrast the establishment of forest cover on sparsely vegetated land, increasing evapotranspiration, deceases water yield. This paper presents a water balance model developed to quantify the sensitivity of runoff production to changes in vegetation based on differences in evapotranspiration from different land cover types. The model is intended to provide a simple framework for estimating long term yield changes due to managed vegetation change. The model assumes that relative potential evapotranspiration from specific land cover can be quantified by a set of potential evapotranspiration coefficients for each land cover type. The model uses the Budyko curve to partition precipitation into evapotranspiration and runoff over the long term. Potential evapotranspiration is estimated from the Budyko curve for present conditions, then adjusted for land cover changes using the relative potential evapotranspiration coefficients for each land cover type. The adjusted potential evapotranspiration is then partitioned using the Budyko curve to provide estimates of long term runoff and evapotranspiration for the changed conditions. We found that the changes in runoff were in general close to being linearly proportional to the changes in land cover. In Utah study watersheds, reducing 50% of the present coniferous forests resulted in runoff increase that ranged from 0.5 to 38 mm/year, while the transition of 50% of area present as range/shrub/other to forest resulted in runoff decrease that ranged from 3.8 to 37 mm/year. The model helps to evaluate long term runoff production sensitivities to vegetation changes and answer, in a broad sense without requiring detailed information or modeling, how much runoff production could potentially be changed through vegetation management. The theoretical approach taken in this study is simple and general and could be applied to a wide range of watersheds.

Is ozone, rather than PM2.5, actually the largest contributor to premature deaths associated with trans-continental transport of air pollution?

NASA Astrophysics Data System (ADS)

Henze, D. K.; Davila, Y.; Anenberg, S.; Malley, C.; Kuylenstierna, J. C. I.; Vallack, H.; Ashmore, M. R.; Turner, M.; Sudo, K.; Jonson, J. E.; Chin, M.; Doherty, R. M.

2017-12-01

While both ozone and PM2.5 contribute to a range of deleterious human health impacts, evaluations of regional and global burdens of disease associated with exposure to these pollutants have concluded that PM2.5 is the larger driver of premature deaths from degraded air quality. This is owing to both high PM2.5 concentrations in heavily populated areas and stronger concentration-response relationships between PM2.5 exposure and increased mortality risk. Meanwhile, both PM2.5 and O3 are formed and/or advected far downwind of their sources and contribute to long-range (trans-continental) pollution transport. Ozone most often makes greater contributions to long-range pollution transport in terms of percent changes in surface-level concentrations given its longer tropospheric lifetime than PM2.5. Combining these factors, previous works have identified PM2.5 as more frequently being the dominant long-range source of air pollution related premature deaths, closely followed by O3. Here we re-evaluate this question using several updates, drawing from ensembles of model simulations performed as part of Phase 2 of the Hemispheric Transport of Air Pollutants (HTAP) project. Most importantly, we use recently revised concentration-response relationships for respiratory (and, less confidently, cardiovascular) disease associated with long-term O3 exposure, which we have shown increases estimates of premature death owing to O3 several-fold, and integrated exposure response (IER) functions for PM2.5. Further, we attempt to overcome well-recognized biases in estimating PM2.5 exposure with global-scale models via assimilation of high resolution (0.1 x 0.1) maps of surface PM2.5 derived from satellite observations. Overall, we find that our revised estimates of long-range O3 and PM2.5 related premature deaths are most often dominated by O3. These findings provide additional incentives for considering the global-scale consequences of regional emissions controls of O3 precursors.

The Pediatric Risk of Mortality Score: Update 2015

PubMed Central

Pollack, Murray M.; Holubkov, Richard; Funai, Tomohiko; Dean, J. Michael; Berger, John T.; Wessel, David L.; Meert, Kathleen; Berg, Robert A.; Newth, Christopher J. L.; Harrison, Rick E.; Carcillo, Joseph; Dalton, Heidi; Shanley, Thomas; Jenkins, Tammara L.; Tamburro, Robert

2016-01-01

Objectives Severity of illness measures have long been used in pediatric critical care. The Pediatric Risk of Mortality is a physiologically based score used to quantify physiologic status, and when combined with other independent variables, it can compute expected mortality risk and expected morbidity risk. Although the physiologic ranges for the Pediatric Risk of Mortality variables have not changed, recent Pediatric Risk of Mortality data collection improvements have been made to adapt to new practice patterns, minimize bias, and reduce potential sources of error. These include changing the outcome to hospital survival/death for the first PICU admission only, shortening the data collection period and altering the Pediatric Risk of Mortality data collection period for patients admitted for “optimizing” care before cardiac surgery or interventional catheterization. This analysis incorporates those changes, assesses the potential for Pediatric Risk of Mortality physiologic variable subcategories to improve score performance, and recalibrates the Pediatric Risk of Mortality score, placing the algorithms (Pediatric Risk of Mortality IV) in the public domain. Design Prospective cohort study from December 4, 2011, to April 7, 2013. Measurements and Main Results Among 10,078 admissions, the unadjusted mortality rate was 2.7% (site range, 1.3–5.0%). Data were divided into derivation (75%) and validation (25%) sets. The new Pediatric Risk of Mortality prediction algorithm (Pediatric Risk of Mortality IV) includes the same Pediatric Risk of Mortality physiologic variable ranges with the subcategories of neurologic and nonneurologic Pediatric Risk of Mortality scores, age, admission source, cardiopulmonary arrest within 24 hours before admission, cancer, and low-risk systems of primary dysfunction. The area under the receiver operating characteristic curve for the development and validation sets was 0.88 ± 0.013 and 0.90 ± 0.018, respectively. The Hosmer-Lemeshow goodness of fit statistics indicated adequate model fit for both the development (p = 0.39) and validation (p = 0.50) sets. Conclusions The new Pediatric Risk of Mortality data collection methods include significant improvements that minimize the potential for bias and errors, and the new Pediatric Risk of Mortality IV algorithm for survival and death has excellent prediction performance. PMID:26492059

Spectral analysis of pipe-to-soil potentials with variations of the Earth's magnetic field in the Australian region

NASA Astrophysics Data System (ADS)

Marshall, R. A.; Waters, C. L.; Sciffer, M. D.

2010-05-01

Long, steel pipelines used to transport essential resources such as gas and oil are potentially vulnerable to space weather. In order to inhibit corrosion, the pipelines are usually coated in an insulating material and maintained at a negative electric potential with respect to Earth using cathodic protection units. During periods of enhanced geomagnetic activity, potential differences between the pipeline and surrounding soil (referred to as pipe-to-soil potentials (PSPs)) may exhibit large voltage swings which place the pipeline outside the recommended "safe range" and at an increased risk of corrosion. The PSP variations result from the "geoelectric" field at the Earth's surface and associated geomagnetic field variations. Previous research investigating the relationship between the surface geoelectric field and geomagnetic source fields has focused on the high-latitude regions where line currents in the ionosphere E region are often the assumed source of the geomagnetic field variations. For the Australian region Sq currents also contribute to the geomagnetic field variations and provide the major contribution during geomagnetic quiet times. This paper presents the results of a spectral analysis of PSP measurements from four pipeline networks from the Australian region with geomagnetic field variations from nearby magnetometers. The pipeline networks extend from Queensland in the north of Australia to Tasmania in the south and provide PSP variations during both active and quiet geomagnetic conditions. The spectral analyses show both consistent phase and amplitude relationships across all pipelines, even for large separations between magnetometer and PSP sites and for small-amplitude signals. Comparison between the observational relationships and model predictions suggests a method for deriving a geoelectric field proxy suitable for indicating PSP-related space weather conditions.

Designing allostery-inspired response in mechanical networks

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

Rocks, Jason W.; Pashine, Nidhi; Bischofberger, Irmgard

Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are then able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ~1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individualmore » response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.« less

Designing allostery-inspired response in mechanical networks

DOE PAGES

Rocks, Jason W.; Pashine, Nidhi; Bischofberger, Irmgard; ...

2017-02-21

Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are then able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ~1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individualmore » response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.« less

Designing allostery-inspired response in mechanical networks

PubMed Central

Rocks, Jason W.; Pashine, Nidhi; Bischofberger, Irmgard; Goodrich, Carl P.; Liu, Andrea J.; Nagel, Sidney R.

2017-01-01

Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ∼1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individual response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks. PMID:28223534

Designing allostery-inspired response in mechanical networks.

PubMed

Rocks, Jason W; Pashine, Nidhi; Bischofberger, Irmgard; Goodrich, Carl P; Liu, Andrea J; Nagel, Sidney R

2017-03-07

Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ∼1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individual response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.

Non-optically combined multispectral source for IR, visible, and laser testing

NASA Astrophysics Data System (ADS)

Laveigne, Joe; Rich, Brian; McHugh, Steve; Chua, Peter

2010-04-01

Electro Optical technology continues to advance, incorporating developments in infrared and laser technology into smaller, more tightly-integrated systems that can see and discriminate military targets at ever-increasing distances. New systems incorporate laser illumination and ranging with gated sensors that allow unparalleled vision at a distance. These new capabilities augment existing all-weather performance in the mid-wave infrared (MWIR) and long-wave infrared (LWIR), as well as low light level visible and near infrared (VNIR), giving the user multiple means of looking at targets of interest. There is a need in the test industry to generate imagery in the relevant spectral bands, and to provide temporal stimulus for testing range-gated systems. Santa Barbara Infrared (SBIR) has developed a new means of combining a uniform infrared source with uniform laser and visible sources for electro-optics (EO) testing. The source has been designed to allow laboratory testing of surveillance systems incorporating an infrared imager and a range-gated camera; and for field testing of emerging multi-spectral/fused sensor systems. A description of the source will be presented along with performance data relating to EO testing, including output in pertinent spectral bands, stability and resolution.

Distribution and importance of microplastics in the marine environment: A review of the sources, fate, effects, and potential solutions.

PubMed

Auta, H S; Emenike, C U; Fauziah, S H

2017-05-01

The presence of microplastics in the marine environment poses a great threat to the entire ecosystem and has received much attention lately as the presence has greatly impacted oceans, lakes, seas, rivers, coastal areas and even the Polar Regions. Microplastics are found in most commonly utilized products (primary microplastics), or may originate from the fragmentation of larger plastic debris (secondary microplastics). The material enters the marine environment through terrestrial and land-based activities, especially via runoffs and is known to have great impact on marine organisms as studies have shown that large numbers of marine organisms have been affected by microplastics. Microplastic particles have been found distributed in large numbers in Africa, Asia, Southeast Asia, India, South Africa, North America, and in Europe. This review describes the sources and global distribution of microplastics in the environment, the fate and impact on marine biota, especially the food chain. Furthermore, the control measures discussed are those mapped out by both national and international environmental organizations for combating the impact from microplastics. Identifying the main sources of microplastic pollution in the environment and creating awareness through education at the public, private, and government sectors will go a long way in reducing the entry of microplastics into the environment. Also, knowing the associated behavioral mechanisms will enable better understanding of the impacts for the marine environment. However, a more promising and environmentally safe approach could be provided by exploiting the potentials of microorganisms, especially those of marine origin that can degrade microplastics. The concentration, distribution sources and fate of microplastics in the global marine environment were discussed, so also was the impact of microplastics on a wide range of marine biota. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Preliminary ZEUS Lightning Location Error Analysis Using a Modified Retrieval Theory

NASA Technical Reports Server (NTRS)

Elander, Valjean; Koshak, William; Phanord, Dieudonne

2004-01-01

The ZEUS long-range VLF arrival time difference lightning detection network now covers both Europe and Africa, and there are plans for further expansion into the western hemisphere. In order to fully optimize and assess ZEUS lightning location retrieval errors and to determine the best placement of future receivers expected to be added to the network, a software package is being developed jointly between the NASA Marshall Space Flight Center (MSFC) and the University of Nevada Las Vegas (UNLV). The software package, called the ZEUS Error Analysis for Lightning (ZEAL), will be used to obtain global scale lightning location retrieval error maps using both a Monte Carlo approach and chi-squared curvature matrix theory. At the core of ZEAL will be an implementation of an Iterative Oblate (IO) lightning location retrieval method recently developed at MSFC. The IO method will be appropriately modified to account for variable wave propagation speed, and the new retrieval results will be compared with the current ZEUS retrieval algorithm to assess potential improvements. In this preliminary ZEAL work effort, we defined 5000 source locations evenly distributed across the Earth. We then used the existing (as well as potential future ZEUS sites) to simulate arrival time data between source and ZEUS site. A total of 100 sources were considered at each of the 5000 locations, and timing errors were selected from a normal distribution having a mean of 0 seconds and a standard deviation of 20 microseconds. This simulated "noisy" dataset was analyzed using the IO algorithm to estimate source locations. The exact locations were compared with the retrieved locations, and the results are summarized via several color-coded "error maps."

New Ways of Treating Data for Diatomic Molecule 'shelf' and Double-Minimum States

NASA Astrophysics Data System (ADS)

Le Roy, Robert J.; Tao, Jason; Khanna, Shirin; Pashov, Asen; Tellinghuisen, Joel

2017-06-01

Electronic states whose potential energy functions have 'shelf' or double-minimum shapes have always presented special challenges because, as functions of vibrational quantum number, the vibrational energies/spacings and inertial rotational constants either have an abrupt change of character with discontinuous slope, or past a given point, become completely chaotic. The present work shows that a `traditional' methodology developed for deep `regular' single-well potentials can also provide accurate `parameter-fit' descriptions of the v-dependence of the vibrational energies and rotational constants of shelf-state potentials that allow a conventional RKR calculation of their Potential energy functions. It is also shown that a merging of Pashov's uniquely flexible 'spline point-wise' potential function representation with Le Roy's `Morse/Long-Range' (MLR) analytic functional form which automatically incorporates the correct theoretically known long-range form, yields an analytic function that incorporates most of the advantages of both approaches. An illustrative application of this method to data to a double-minimum state of Na_2 will be described.

Influence of the contact potential and space-charge effect on the performance of a Stoffel-Johnson design electron source for inverse photoemission spectroscopy

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

Maniraj, M.; Barman, Sudipta Roy

By imaging the spatial intensity distribution of the electrons from a Stoffel-Johnson (SJ) type low energy electron source for inverse photoemission spectroscopy (IPES), we find that the focus is distorted when the beam current exceeds the limiting value due to space charge effect. The space charge effect and the contact potential difference suppress the beam current at low energies (<10 eV). In this work, we show that these limitations of the SJ source can be overcome by compensation of the contact potential difference between the cathode and the lens electrodes and an uniform well focused electron beam with the set kineticmore » energy can be obtained. The size of the electron beam is around 1 mm full width at half maximum over the whole energy range of 5 to 30 eV generally used for IPES. The compensation of the contact potential difference also enhances the beam current substantially at low energies (<10 eV) and uniform beam current is achieved for the whole energy range. We find that the drift in the electron beam position is sensitive to the lens electrode separation and it is about 1 mm over the whole energy range. By measuring the n = 1 image potential state on Cu(100), we show that the resolution is better when the cathode filament current is set to lower values.« less

Natural nano-structures on insects—possible functions of ordered arrays characterized by atomic force microscopy

NASA Astrophysics Data System (ADS)

Watson, G. S.; Watson, J. A.

2004-07-01

Naturally occurring nano-structures is a much-neglected, but potentially rich, source of products that meet specifications imposed by natural selection. While the pharmaceutical industry has long recognized the value of natural compounds, the emerging industries based on nanotechnology have so far made little use of 'free' technology that has been 'invented' over evolutionary time-scales and driven by the imperatives of species survival. Ordered hexagonal packed array structures on cicada (e.g., Pflatoda claripennis) and termite (e.g., family Rhinotermitidae) wings have been investigated in this study. The spacings range from 200 to 1000 nm. The structures tend to have a rounded shape at the apex and protrude some 150-350 nm out from the surface plane. Wing structures with spacings at the lower end of the range are most likely optimized to serve as an anti-reflective coating (natural 'stealth technology') but may also act as a self-cleaning coating (the Lotus effect). Structures with spacings at the upper end of the range may provide mechanical strength to prevent load failure under flight and/or aid in the aerodynamic efficiency of the insect. This study demonstrates the multi-purpose design of natural structures.

Comparison of seven kinds of drinking water treatment processes to enhance organic material removal: a pilot test.

PubMed

Chen, Chao; Zhang, Xiaojian; He, Wenjie; Lu, Wei; Han, Hongda

2007-08-15

Organic matter in source water has presented many challenges in the field of water purification, especially for conventional treatment. A two-year-long pilot test comparing water treatment processes was conducted to enhance organic matter removal. The tested process combinations included the conventional process, conventional plus advanced treatment, pre-oxidation plus conventional process and pre-oxidation plus conventional plus advanced treatment. The efficiency of each kind of process was assayed with the comprehensive indices of COD(Mn), TOC, UV(254), AOC, BDOC, THMs, and HAAs and their formation potential. The results showed that the combination of the conventional process and O(3)-BAC provides integrated removal of organic matter and meets the required standards. It is the best performing treatment tested in this investigation for treating polluted source water in China. Moreover, much attention should be paid to organic removal before disinfection to control DBP formation and preserve biostability. This paper also reports the range of efficiency of each unit process to calculate the total efficiency of different process combinations in order to help choose the appropriate water treatment process.

Airborne trace contaminants of possible interest in CELSS

NASA Technical Reports Server (NTRS)

Garavelli, J. S.

1986-01-01

One design goal of Closed Ecological Life Support Systems (CELSS) for long duration space missions is to maintain an atmosphere which is healthy for all the desirable biological species and not deleterious to any of the mechanical components in that atmosphere. CELESS design must take into account the interactions of at least six major components; (1) humans and animals, (2) higher plants, (3) microalgae, (4) bacteria and fungi, (5) the waste processing system, and (6) other mechanical systems. Each of these major components can be both a source and a target of airborne trace contaminants in a CELSS. A range of possible airborne trace contaminants is discussed within a chemical classification scheme. These contaminants are analyzed with respect to their probable sources among the six major components and their potential effects on those components. Data on airborne chemical contaminants detected in shuttle missions is presented along with this analysis. The observed concentrations of several classes of compounds, including hydrocarbons, halocarbons, halosilanes, amines and nitrogen oxides, are considered with respect to the problems which they present to CELSS.

Long wavelength optical mode frequencies and the Anderson-Gruneisen parameter for alkali halide crystals

NASA Astrophysics Data System (ADS)

Gupta, A. P.; Shanker, Jai

1980-02-01

The relation between long wavelength optical mode frequencies and the Anderson-Gruneisen parameter δ for alkali halides studied by Madan suffers from a mathematical error which is rectified in the present communication. A theoretical analysis of δ is presented adopting six potential functions for the short range repulsion energy. Values of δ and γTO calculated from the Varshni-Shukla potential are found in closest agreement with experimental data.

Impact of primary and secondary organic sources on the oxidative potential of quasi-ultrafine particles (PM0.25) at three contrasting locations in the Los Angeles Basin

NASA Astrophysics Data System (ADS)

Saffari, Arian; Hasheminassab, Sina; Wang, Dongbin; Shafer, Martin M.; Schauer, James J.; Sioutas, Constantinos

2015-11-01

To investigate the changing contribution of primary and secondary sources on the oxidative potential of particulate matter (PM) in a real-world urban atmosphere, 7 sets of quasi-ultrafine particles (PM0.25) were collected at three contrasting locations in the Los Angeles Basin, California, USA. Samples were collected in the coastal area of Long Beach during the morning rush hour period, representing fresh primary emissions from nearby freeways and the LA port; in central Los Angeles during midday, representing a mixture of fresh primary emissions and early products of photochemical secondary organic aerosol (SOA) formation; and at a downwind site (Upland) during afternoon, when the impacts of photochemically aged secondary PM are significant. Chemical composition showed distinctive trends, with the lowest fraction of water soluble organic carbon (WSOC) and other organic tracers of SOA formation (e.g. organic acids) at Long Beach, and the lowest abundance of organic tracers of primary vehicular emissions (such as polycyclic aromatic hydrocarbons and hopanes) at Upland. A molecular marker-based chemical mass balance (MM-CMB) model indicated that 72% of the total organic carbon at Long Beach was comprised of primary vehicular sources (combined heavy duty and light duty vehicles), while the vehicular fraction was found to be 50% and 39% at Los Angeles and Upland, respectively. Regression analysis suggested that at Long Beach, the variation in oxidative potential of PM0.25 (quantified using a macrophage-based reactive oxygen species (ROS) assay) was mainly driven by mobile vehicular emissions and the water-insoluble fraction of the organic carbon. In contrast, at Upland, where photochemical processing and secondary aerosol formation was the highest, WSOC and secondary organics were the major drivers of the oxidative potential variation. The multivariate regression analysis also indicated that as much as 58% of the overall spatial and temporal variation in the oxidative potential of PM0.25 at these three locations can be explained by mobile emissions and SOA.

Evaluation of Long-term Performance of Enhanced Anaerobic Source Zone Bioremediation using mass flux

NASA Astrophysics Data System (ADS)

Haluska, A.; Cho, J.; Hatzinger, P.; Annable, M. D.

2017-12-01

Chlorinated ethene DNAPL source zones in groundwater act as potential long term sources of contamination as they dissolve yielding concentrations well above MCLs, posing an on-going public health risk. Enhanced bioremediation has been applied to treat many source zones with significant promise, but long-term sustainability of this technology has not been thoroughly assessed. This study evaluated the long-term effectiveness of enhanced anaerobic source zone bioremediation at chloroethene contaminated sites to determine if the treatment prevented contaminant rebound and removed NAPL from the source zone. Long-term performance was evaluated based on achieving MCL-based contaminant mass fluxes in parent compound concentrations during different monitoring periods. Groundwater concertation versus time data was compiled for 6-sites and post-remedial contaminant mass flux data was then measured using passive flux meters at wells both within and down-gradient of the source zone. Post-remedial mass flux data was then combined with pre-remedial water quality data to estimate pre-remedial mass flux. This information was used to characterize a DNAPL dissolution source strength function, such as the Power Law Model and the Equilibrium Stream tube model. The six-sites characterized for this study were (1) Former Charleston Air Force Base, Charleston, SC; (2) Dover Air Force Base, Dover, DE; (3) Treasure Island Naval Station, San Francisco, CA; (4) Former Raritan Arsenal, Edison, NJ; (5) Naval Air Station, Jacksonville, FL; and, (6) Former Naval Air Station, Alameda, CA. Contaminant mass fluxes decreased for all the sites by the end of the post-treatment monitoring period and rebound was limited within the source zone. Post remedial source strength function estimates suggest that decreases in contaminant mass flux will continue to occur at these sites, but a mass flux based on MCL levels may never be exceeded. Thus, site clean-up goals should be evaluated as order-of-magnitude reductions. Additionally, sites may require monitoring for a minimum of 5-years in order to sufficiently evaluate remedial performance. The study shows that enhanced anaerobic source zone bioremediation contributed to a modest reduction of source zone contaminant mass discharge and appears to have mitigated rebound of chlorinated ethenes.

Transport of chemical and microbial compounds from known wastewater discharges: Potential for use as indicators of human fecal contamination

USGS Publications Warehouse

Glassmeyer, S.T.; Furlong, E.T.; Kolpin, D.W.; Cahill, J.D.; Zaugg, S.D.; Werner, S.L.; Meyer, M.T.; Kryak, D.D.

2005-01-01

The quality of drinking and recreational water is currently (2005) determined using indicator bacteria. However, the culture tests used to analyze for these bacteria require a long time to complete and do not discriminate between human and animal fecal material sources. One complementary approach is to use chemicals found in human wastewater, which would have the advantages of (1) potentially shorter analysis times than the bacterial culture tests and (2) being selected for human-source specificity. At 10 locations, water samples were collected upstream and at two successive points downstream from a wastewaster treatment plant (WWTP); a treated effluent sample was also collected at each WWTP. This sampling plan was used to determine the persistence of a chemically diverse suite of emerging contaminants in streams. Samples were also collected at two reference locations assumed to have minimal human impacts. Of the 110 chemical analytes investigated in this project, 78 were detected at least once. The number of compounds in a given sample ranged from 3 at a reference location to 50 in a WWTP effluent sample. The total analyte load at each location varied from 0.018 μg/L at the reference location to 97.7 μg/L in a separate WWTP effluent sample. Although most of the compound concentrations were in the range of 0.01−1.0 μg/L, in some samples, individual concentrations were in the range of 5−38 μg/L. The concentrations of the majority of the chemicals present in the samples generally followed the expected trend:  they were either nonexistent or at trace levels in the upstream samples, had their maximum concentrations in the WWTP effluent samples, and then declined in the two downstream samples. This research suggests that selected chemicals are useful as tracers of human wastewater discharge.

Long-term consistency in spatial patterns of primate seed dispersal.

PubMed

Heymann, Eckhard W; Culot, Laurence; Knogge, Christoph; Noriega Piña, Tony Enrique; Tirado Herrera, Emérita R; Klapproth, Matthias; Zinner, Dietmar

2017-03-01

Seed dispersal is a key ecological process in tropical forests, with effects on various levels ranging from plant reproductive success to the carbon storage potential of tropical rainforests. On a local and landscape scale, spatial patterns of seed dispersal create the template for the recruitment process and thus influence the population dynamics of plant species. The strength of this influence will depend on the long-term consistency of spatial patterns of seed dispersal. We examined the long-term consistency of spatial patterns of seed dispersal with spatially explicit data on seed dispersal by two neotropical primate species, Leontocebus nigrifrons and Saguinus mystax (Callitrichidae), collected during four independent studies between 1994 and 2013. Using distributions of dispersal probability over distances independent of plant species, cumulative dispersal distances, and kernel density estimates, we show that spatial patterns of seed dispersal are highly consistent over time. For a specific plant species, the legume Parkia panurensis , the convergence of cumulative distributions at a distance of 300 m, and the high probability of dispersal within 100 m from source trees coincide with the dimension of the spatial-genetic structure on the embryo/juvenile (300 m) and adult stage (100 m), respectively, of this plant species. Our results are the first demonstration of long-term consistency of spatial patterns of seed dispersal created by tropical frugivores. Such consistency may translate into idiosyncratic patterns of regeneration.

Long-term follow-up and outcome in patients with recurrent respiratory laryngeal papillomatosis.

PubMed

Rasmussen, Eva Rye; Schnack, Didde T; Jørkov, Andreas Schjellerup; Raja, Anna Axelsson; Olsen, Caroline Holkmann; Homøe, Preben

2017-12-01

Recurrent respiratory papillomatosis is characterized by wart-like lesions of the upper airway and is most frequently caused by human papillomavirus (HPV). The disease has significant impact on quality of life due to potential airway obstruction, dysphonia and the need for serial surgeries. The main objective of this study was to describe patient characteristics and long-term follow-up data in a Danish cohort with the disease. The study was a longitudinal retrospective cohort-study using data from electronic medical records and a pathology database. A total of 61 adult and four juvenile patients were identified. The male-to-female ratio was 2.4. In the adult population, the mean age at onset was 45 years. The median number of surgeries was four (interquartile range: 2.8). The mean follow-up time was 8.7 years (range: 7 days-30 years). Three cases of malignant transformation were observed. In the juvenile population, the mean age of onset was 8.5 years (range: 3-12 years). The mean follow-up time was 11.5 years (range: 2-23 years), and the number of surgeries per year at risk was one/year. CO2-laser and microdebrider were the surgical techniques usually employed. 43% of histopathologic analyses could detect HPV infection (subtype 6 or 11). More males than females suffer from respiratory papillomatosis; age of onset was either in childhood or in mid-life. Use of CO2-laser or microdebrider was the preferred surgical approach in this cohort. none. not relevant. Articles published in the DMJ are “open access”. This means that the articles are distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits any non-commercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Identification of long-range transport of aerosols over Austria using EARLINET lidar measurements

NASA Astrophysics Data System (ADS)

Camelia, Talianu

2018-04-01

The aims of the study is to identify the paths of the long-range transported aerosols over Austria and their potential origin, and to estimate their properties, using lidar measurements from EARLINET stations closest to Austria from Germany and Romania and aerosol transport models. As of now, there is no lidar station in Austria. The study is part of a project to estimate the usefulness of a lidar station located in Vienna, Austria.

Efficient Long-Range Hole Transport Through G-Quadruplexes.

PubMed

Wu, Jingyuan; Meng, Zhenyu; Lu, Yunpeng; Shao, Fangwei

2017-10-09

DNA offers a means of long-range charge transport for biology and electric nanodevices. Here, a series of tetra-stranded G-quadruplexes were assembled within a dendritic DNA architecture to explore oxidative charge transport (hole transport) through the G-quadruplex. Efficient charge transport was achieved over 28 Å upon UV irradiation. Over a longer G-quadruplex bridge, hole transport was escalated to a higher efficiency, which resulted in a higher yield than that of the optimal duplex DNA for charge transport, that is, the adenine tract. Efficient long-range hole transport suggests tetra-stranded G-quadruplexes, instead of an oxidation hotspot, hold better potential as an electron conduit than duplex DNA. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Using short-range and long-range functional connectivity to identify schizophrenia with a family-based case-control design.

PubMed

Guo, Wenbin; Liu, Feng; Chen, Jindong; Wu, Renrong; Li, Lehua; Zhang, Zhikun; Chen, Huafu; Zhao, Jingping

2017-06-30

Abnormal short-range and long-range functional connectivities (FCs) have been implicated in the neurophysiology of schizophrenia. This study was conducted to examine the potential of short-range and long-range FCs for differentiating the patients from the controls with a family-based case-control design. Twenty-eight first-episode, drug-naive patients with schizophrenia, 28 unaffected siblings of the patients (family-based controls, FBCs), and 40 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging (fMRI) scans. The data were analyzed by short-range and long-range FC analyses, receiver operating characteristic curve (ROC) and support vector machine (SVM). Compared with the FBCs/HCs, the patients exhibit increased short-range positive FC strength (spFCS) and/or long-range positive FC strength (lpFCS) in the default-mode network (DMN) and decreased spFCS and lpFCS in the sensorimotor circuits. Furthermore, a combination of the spFCS values in the right superior parietal lobule and the lpFCS values in the left fusiform gyrus/cerebellum VI can differentiate the patients from the FBCs with high sensitivity and specificity. The findings highlight the importance of the DMN and sensorimotor circuits in the pathogenesis of schizophrenia. Combining with family-based case-control design may be a viable option to limit the confounding effects of environmental risk factors in neuroimaging studies of schizophrenia. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Long-range Acoustic Interactions in Insect Swarms - An Adaptive Gravity Model

NASA Astrophysics Data System (ADS)

Gorbonos, Dan; Ianconescu, Reuven; Puckett, James G.; Ni, Rui; Ouellette, Nicholas T.; Gov, Nir S.

The collective motion of groups of animals emerges from the net effect of the interactions between individual members of the group. In many cases, such as birds, fish, or ungulates, these interactions are mediated by sensory stimuli that predominantly arise from nearby neighbors. But not all stimuli in animal groups are short range. We consider mating swarms of midges, which are thought to interact primarily via long-range acoustic stimuli. We exploit the similarity in form between the decay of acoustic and gravitational sources to build a model for swarm behavior. By accounting for the adaptive nature of the midges' acoustic sensing, we show that our ``adaptive gravity'' model makes mean-field predictions that agree well with experimental observations of laboratory swarms. Our results highlight the role of sensory mechanisms and interaction range in collective animal behavior. Additionally, the adaptive interactions open a new class of equations of motion, which may appear in other biological contexts.

Occupational noise exposure during endourologic procedures.

PubMed

Soucy, Frédéric; Ko, Raymond; Denstedt, John D; Razvi, Hassan

2008-08-01

Long-term noise exposure in the workplace is a known cause of hearing loss. There has been limited study on the potential harm related to shock wave lithotripsy (SWL) or intracorporeal devices on patients and operating room personnel. We used a digital sound meter to measure decibel levels in the operating room during several endourologic procedures. The decibel levels were recorded during SWL (Storz SLX-F2), percutaneous nephrolithotomy using single- and dual-probe ultrasonic lithotripters (Olympus LUS-2, CyberWand), and during ureteroscopy using the Versa Pulse Holmium:YAG laser. Findings were compared with the U.S. Department of Labor Occupational Health and Safety Administration and Canadian Centre for Occupational Health recommendations on permissible noise levels in the workplace. The background sound level in the operating room prior to endourologic procedures ranged between 58 and 60 dB. In the SWL control room, 5 m from the source, the mean sound level was 68 dB (range 64-75) during treatment. The mean corresponding decibel level recorded at the patient's head during SWL was 77 dB (range 73-83). Noises produced by intracorporeal lithotripters were recorded at the surgeon's head, 2 m from the source. Measurements of the CyberWand (dual-probe) device revealed a higher mean decibel reading of 93 dB (range 85-102). Noise levels recorded for the Olympus LUS-2 (single-probe) ultrasound and the holmium laser were 65 dB (62 -68) and 60 dB (58-62), respectively. Although we noted that patients and urologists maybe exposed to significant noise levels during endourologic procedures, the duration of exposure is short. This risk appears to be minimal, based on current occupational guidelines, for most operating personnel.

[Characterization of a thermophilic Geobacillus strain DM-2 degrading hydrocarbons].

PubMed

Liu, Qing-kun; Wang, Jun; Li, Guo-qiang; Ma, Ting; Liang, Feng-lai; Liu, Ru-lin

2008-12-01

A thermophilic Geobacillus strain DM-2 from a deep-subsurface oil reservoir was investigated on its capability of degrading crude oil under various conditions as well as its characters on degrading hydrocarbons in optimal conditions. The results showed that Geobacillus strain DM-2 was able to degrade crude oil under anoxic wide-range conditions with pH ranging from 4.0 to 10.0, high temperature in the range of 45-70 degrees C and saline concentration ranging from 0.2% to 3.0%. Furthermore, the optimal temperature and pH value for utilizing hydrocarbons by the strain were 60 degrees C and 7.0, respectively. Under such optimal conditions, the strain utilized liquid paraffine emulsified by itself as its carbon source for growth; further analysis by gas chromatography (GC) and infrared absorption spectroscopy demonstrated that it was able to degrade n-alkanes (C14-C30), branched-chain alkanes and aromatic hydrocarbons in crude oil and could also utilize long-chain n-alkanes from C16 to C36, among of which the degradation efficiency of C28 was the highest, up to 88.95%. One metabolite of the strain oxidizing alkanes is fatty acid.While utilizing C16 as carbon source for 5 d, only one fatty acid-acetic acid was detected by HPLC and MS as the product, with the amount of 0.312 g/L, which indicated that it degraded n-alkanes with pathway of inferior terminal oxidation,and then followed by a beta-oxidation pathway. Due to its characters of efficient emulsification, high-performance degradation of hydrocarbons and fatty-acid production under high temperature and anoxic condition, the strain DM-2 may be potentially applied to oil-waste treatment and microbial enhanced heavy oil recovery in extreme conditions.

Long- range transport of Xe-133 emissions under convective and non-convective conditions.

NASA Astrophysics Data System (ADS)

Kusmierczyk-Michulec, Jolanta; Gheddou, Abdelhakim

2015-04-01

The International Monitoring System (IMS) developed by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) is a global system of monitoring stations, using four complementary technologies: seismic, hydroacoustic, infrasound and radionuclide. Data from all stations, belonging to IMS, are collected and transmitted to the International Data Centre (IDC) in Vienna, Austria. The radionuclide network comprises 80 stations, of which more than 60 are certified. The aim of radionuclide stations is a global monitoring of radioactive aerosols and radioactive noble gases, in particular xenon isotopes, supported by the atmospheric transport modeling (ATM). The aim of this study is to investigate the long-range transport of Xe-133 emissions under convective and non-convective conditions. For that purpose a series of 14 days forward simulations was conducted using the Lagrangian Particle Diffusion Model FLEXPART, designed for calculating the long-range and mesoscale dispersion of air pollution from point sources. The release point was at the ANSTO facility in Australia. The geographical localization to some extent justifies the assumption that the only source of Xe-133 observed at the neighbouring stations, comes from the ANSTO facility. In the simulations the analysed wind data provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) were used with the spatial resolution of 0.5 degree. Studies have been performed to link Xe-133 emissions with detections at the IMS stations supported by the ATM, and to assess the impact of atmospheric convection on non-detections at the IMS stations. The results of quantitative and qualitative comparison will be presented.

Effect of Carbon-Cycle Uncertainty on Estimates of the 1.5oC Carbon Budget

NASA Astrophysics Data System (ADS)

Mengis, N.; Jalbert, J.; Partanen, A. I.; Matthews, D.

2017-12-01

In December 2015, the participants of the COP21 agreed to pursue efforts to limit global temperature increase to 1.5oC relative to the preindustrial level. A robust estimate of the carbon budget for this temperature target is one precondition for well-informed political discussions. These estimates, however, depend on Earth system models and need to account for model inherent uncertainties. Here, we quantify the effect of carbon cycle uncertainty within an intermediate complexity Earth system model. Using an Bayesian inversion approach we obtain a probabilistic estimate for the 1.5oC carbon budget of 66 PgC with a range of 20 to 112 PgC. This estimate is in good agreement with the IPCC's estimate, and additionally provides a probabilistic range accounting for uncertainties in the natural carbon sinks. Furthermore our results suggest, that for a long-term temperature stabilization at 1.5oC, negative fossil fuel emissions in the order of 1 PgC yr-1 would be needed. Two effects cause the fossil fuel emissions during temperature stabilization to turn negative: 1) The reduced uptake potential of the natural carbon sinks, which arises from increasing ocean temperatures, and the fact that the land turns from a net carbon sink to a source. 2) The residual positive anthropogenic forcing in the extended scenario, which remains as high as 2.5 W m-2, until the end of 2200. In contrast to previous studies our results suggest the need for negative fossil fuel emissions for a long term temperature stabilization to compensate for residual anthropogenic forcing and a decreasing natural carbon sink potential.

FORAGES AND PASTURES SYMPOSIUM: Improving efficiency of production in pasture- and range-based beef and dairy systems.

PubMed

Mulliniks, J T; Rius, A G; Edwards, M A; Edwards, S R; Hobbs, J D; Nave, R L G

2015-06-01

Despite overall increased production in the last century, it is critical that grazing production systems focus on improving beef and dairy efficiency to meet current and future global food demands. For livestock producers, production efficiency is essential to maintain long-term profitability and sustainability. This continued viability of production systems using pasture- and range-based grazing systems requires more rapid adoption of innovative management practices and selection tools that increase profitability by optimizing grazing management and increasing reproductive performance. Understanding the genetic variation in cow herds will provide the ability to select cows that require less energy for maintenance, which can potentially reduce total energy utilization or energy required for production, consequently improving production efficiency and profitability. In the United States, pasture- and range-based grazing systems vary tremendously across various unique environments that differ in climate, topography, and forage production. This variation in environmental conditions contributes to the challenges of developing or targeting specific genetic components and grazing systems that lead to increased production efficiency. However, across these various environments and grazing management systems, grazable forage remains the least expensive nutrient source to maintain productivity of the cow herd. Beef and dairy cattle can capitalize on their ability to utilize these feed resources that are not usable for other production industries. Therefore, lower-cost alternatives to feeding harvested and stored feedstuffs have the opportunity to provide to livestock producers a sustainable and efficient forage production system. However, increasing production efficiency within a given production environment would vary according to genetic potential (i.e., growth and milk potential), how that genetic potential fits the respective production environment, and how the grazing management fits within those genetic parameters. Therefore, matching cow type or genetic potential to the production environment is and will be more important as cost of production increases.

Evaluation of a scale-model experiment to investigate long-range acoustic propagation

NASA Technical Reports Server (NTRS)

Parrott, Tony L.; Mcaninch, Gerry L.; Carlberg, Ingrid A.

1987-01-01

Tests were conducted to evaluate the feasibility of using a scale-model experiment situated in an anechoic facility to investigate long-range sound propagation over ground terrain. For a nominal scale factor of 100:1, attenuations along a linear array of six microphones colinear with a continuous-wave type of sound source were measured over a wavelength range from 10 to 160 for a nominal test frequency of 10 kHz. Most tests were made for a hard model surface (plywood), but limited tests were also made for a soft model surface (plywood with felt). For grazing-incidence propagation over the hard surface, measured and predicted attenuation trends were consistent for microphone locations out to between 40 and 80 wavelengths. Beyond 80 wavelengths, significant variability was observed that was caused by disturbances in the propagation medium. Also, there was evidence of extraneous propagation-path contributions to data irregularities at more remote microphones. Sensitivity studies for the hard-surface and microphone indicated a 2.5 dB change in the relative excess attenuation for a systematic error in source and microphone elevations on the order of 1 mm. For the soft-surface model, no comparable sensitivity was found.

On the mechanical theory for biological pattern formation

NASA Astrophysics Data System (ADS)

Bentil, D. E.; Murray, J. D.

1993-02-01

We investigate the pattern-forming potential of mechanical models in embryology proposed by Oster, Murray and their coworkers. We show that the presence of source terms in the tissue extracellular matrix and cell density equations give rise to spatio-temporal oscillations. An extension of one such model to include ‘biologically realistic long range effects induces the formation of stationary spatial patterns. Previous attempts to solve the full system were in one dimension only. We obtain solutions in one dimension and extend our simulations to two dimensions. We show that a single mechanical model alone is capable of generating complex but regular spatial patterns rather than the requirement of model interaction as suggested by Nagorcka et al. and Shaw and Murray. We discuss some biological applications of the models among which are would healing and formation of dermatoglyphic (fingerprint) patterns.

Pursuit and Synchronization in Hydrodynamic Dipoles

NASA Astrophysics Data System (ADS)

Kanso, Eva; Tsang, Alan Cheng Hou

2015-10-01

We study theoretically the behavior of a class of hydrodynamic dipoles. This study is motivated by recent experiments on synthetic and biological swimmers in microfluidic Hele-Shaw type geometries. Under such confinement, a swimmer's hydrodynamic signature is that of a potential source dipole, and the long-range interactions among swimmers are obtained from the superposition of dipole singularities. Here, we recall the equations governing the positions and orientations of interacting asymmetric swimmers in doubly periodic domains and focus on the dynamics of pairs of swimmers. We obtain two families of "relative equilibria"-type solutions that correspond to pursuit and synchronization of the two swimmers. Interestingly, the pursuit mode is stable for large-tail swimmers, whereas the synchronization mode is stable for large-head swimmers. These results have profound implications on the collective behavior reported in several recent studies on populations of confined microswimmers.

Challenges and opportunities of power systems from smart homes to super-grids.

PubMed

Kuhn, Philipp; Huber, Matthias; Dorfner, Johannes; Hamacher, Thomas

2016-01-01

The world's power systems are facing a structural change including liberalization of markets and integration of renewable energy sources. This paper describes the challenges that lie ahead in this process and points out avenues for overcoming different problems at different scopes, ranging from individual homes to international super-grids. We apply energy system models at those different scopes and find a trade-off between technical and social complexity. Small-scale systems would require technological breakthroughs, especially for storage, but individual agents can and do already start to build and operate such systems. In contrast, large-scale systems could potentially be more efficient from a techno-economic point of view. However, new political frameworks are required that enable long-term cooperation among sovereign entities through mutual trust. Which scope first achieves its breakthrough is not clear yet.

Free-piston Stirling component test power converter

NASA Technical Reports Server (NTRS)

Dochat, George; Dhar, Manmohan

1991-01-01

The National Aeronautics and Space Administration (NASA) has been evaluating free-piston Stirling power converters (FPSPCs) for use on a wide variety of space missions. They provide high reliability, long life, and efficient operation and can be coupled with all potential heat sources, various heat input and heat rejection systems, and various power management and distribution systems. FPSPCs can compete favorably with alternative power conversion systems over a range of hundreds of watts to megawatts. Mechanical Technology Incorporated (MTI) is developing FPSPC technology under contract to NASA Lewis Research Center and will demonstrate this technology in two full-scale power converters operating at space temperature conditions. The testing of the first of these, the component test power converter (CTPC), was initiated in Spring 1991 to evaluate mechanical operation at space operating temperatures. The CTPC design, hardware fabrication, and initial test results are reviewed.

Styles and Timing of Volatile-driven Activity in the Eastern Hellas Region of Mars

NASA Technical Reports Server (NTRS)

Crown, David A.; Bleamaster, Leslie F., III; Mest, Scott C.; Teneva, Lida T.

2005-01-01

Hellas basin, the largest well-preserved impact structure on the Martian surface, is Mars deepest depositional sink and has long been recognized as a source for global dust storms. The basin and surrounding highlands span a wide range in latitude and elevation, exhibit landforms shaped by a diversity of geologic processes, and preserve exposures of Noachian, Hesperian, and Amazonian units. Geologically contemporaneous volcanism and volatile-driven activity in the circum-Hellas highlands provide resources for potential Martian life. Hellas is a geologically significant region for evaluating volatile abundance, distribution and cycling and changes in surface conditions on Mars. Current work integrates geologic studies of the basin floor and east rim using Viking Orbiter, Mars Global Surveyor, and Mars Odyssey datasets to provide a synthesis of the history of volatiles in the region.

Recapturing nutrients from dairy waste using biochar

NASA Astrophysics Data System (ADS)

Sarkhot, D.; Ghezzehei, T. A.; Berhe, A. A.

2009-12-01

Biochar or biomass derived black carbon is known to be highly resistant to decomposition with half-life periods ranging from hundreds of years to millennia. It is also reported to enhance soil productivity due to high nutrient retention and favorable effects on soil pH, water retention capacity as well as microbial population. Brazilian Terra Preta soils have shown the potential of biochar for long-term carbon sequestration capacity and productivity of soil and many researchers have now focused on utilizing this phenomenon to create fertile, carbon-rich soils, called Terra Preta Nova. Although the highly adsorptive nature of biochar is well characterized, the potential for using biochar in environmental cleanup efforts is relatively unexplored. Dairy waste is a source of significant water pollution because it introduces excess nutrients such as phosphates and nitrates into the soil and water system. Since many soils have limited capacity to retain nitrate and phosphate, especially for long periods of time, the utility of dairy waste manure to enhance soil fertility and nutrient availability to plants is limited. Here, we present results from a project that we started to determine the potential of biochar to recover the excess nutrients from dairy flushed manure. In this initial study, a commercially available biochar amendment was ground and used in a batch sorption experiment with the dairy flushed manure from a local dairy in Merced, California. Four manure dilutions viz. 10, 25, 50 and 100%, and three shaking times, viz. 1, 12 and 24 hours were used for this study. We then calculated the amount of ammonia, nitrate and phosphate adsorbed by the biochar using differences in nutrient concentrations before and after the sorption experiment. Biochar showed significant capacity of adsorbing these nutrients, suggesting a potential for controlling the dairy pollution. The resulting enriched biochar can potentially act as a slow release fertilizer and enhance soil productivity as well as increasing the long-term carbon sequestration potential of soils. We are currently initiating further research to determine the desorption potenial of the biochar sorbed nutrients in soil.

Post-fire Water Quality in the Western United States: Understanding and Predicting Short and Long-term Response

NASA Astrophysics Data System (ADS)

Hogue, T. S.; Rust, A.

2016-12-01

Fire frequency is increasing across mid-elevation forests, especially in the Northern Rockies, Sierra Nevada, southern Cascades, as well as the coastal ranges in California and southern Oregon. Numerous studies have noted increased discharge, floods and debris flows after wildfire. More recent work also shows increased water yield during dry seasons for up to ten years post-fire. However, few studies have evaluated long-term water quality response in fire-impacted watersheds. The current presentation will overview recent development of an extensive database on post-fire water quality response across the western U.S. A range of water quality parameters were gathered from 271 burned watersheds through local, state and federal agencies. Short and long-term response was evaluated for watersheds with at least 5 years of pre-fire data. Over 30 watersheds showed significant increases in NO3-, NO2-, NH3, and total nitrogen loading in the initial five years after fire and remained elevated ten years after fire. The burn severity influenced the degree of nitrogen response, where more severely burned watersheds showed higher nitrogen loading than less severely burned watersheds. Dissolved and total phosphorous showed significant increases in 32 watersheds for the first five years after fire. Dissolved ions such as calcium, magnesium, and chloride were also exported from over 32 watersheds, primarily during the first five years after fire, with the majority of impacted watersheds returning to pre-fire water quality conditions after ten years. Ongoing work includes evaluating key determinants that drive short and long-term response and developing predictive models for post-fire water quality. Watersheds impacted by wildfire are known to pose significant risks for downstream communities. Understanding short and long-term water quality change that can impact regional water supplies is critical for establishing potential treatment priorities and alternative source planning.

Levels and potential sources of decabromodiphenyl ethane (DBDPE) and decabromodiphenyl ether (DecaBDE) in lake and marine sediments in Sweden.

PubMed

Ricklund, Niklas; Kierkegaard, Amelie; McLachlan, Michael S

2010-03-15

Decabromodiphenyl ethane (DBDPE) is a brominated flame retardant (BFR) used as a replacement for the structurally similar decabromodiphenyl ether (decaBDE), which is a regulated environmental contaminant of concern. DBDPE has been found in indoor dust, sewage sludge, sediment, and biota, but little is known about its occurrence and distribution in the environment In this paper, sediment was analyzed from 11 isolated Swedish lakes and along a transect running from central Stockholm through the Stockholm archipelago to the Baltic Sea. DBDPE was present in all samples. In lake sediment, the levels ranged from 0.23 to 11 ng/g d.wt. and were very similar to the levels of decaBDE (0.48-11 ng/g d.wt.). Since the lakes have no known point sources of BFRs, their presence in the sediments provides evidence for long-range atmospheric transport and deposition. In the marine sediment, the DBDPE and decaBDE levels decreased by a factor of 20-50 over 40 km from the inner harbor to the outer archipelago. There the DBDPE and decaBDE levels were similar to the levels in nearby isolated lakes. The results indicate that contamination of the Swedish environment with DBDPE has already approached that of decaBDE, and that this contamination is primarily occurring via the atmosphere.

Exploring variations of earthquake moment on patches with heterogeneous strength

NASA Astrophysics Data System (ADS)

Lin, Y. Y.; Lapusta, N.

2016-12-01

Finite-fault inversions show that earthquake slip is typically non-uniform over the ruptured region, likely due to heterogeneity of the earthquake source. Observations also show that events from the same fault area can have the same source duration but different magnitude ranging from 0.0 to 2.0 (Lin et al., GJI, 2016). Strong heterogeneity in strength over a patch could provide a potential explanation of such behavior, with the event duration controlled by the size of the patch and event magnitude determined by how much of the patch area has been ruptured. To explore this possibility, we numerically simulate earthquake sequences on a rate-and-state fault, with a seismogenic patch governed by steady-state velocity-weakening friction surrounded by a steady-state velocity-strengthening region. The seismogenic patch contains strong variations in strength due to variable normal stress. Our long-term simulations of slip in this model indeed generate sequences of earthquakes of various magnitudes. In some seismic events, dynamic rupture cannot overcome areas with higher normal strength, and smaller events result. When the higher-strength areas are loaded by previous slip and rupture, larger events result, as expected. Our current work is directed towards exploring a range of such models, determining the variability in the seismic moment that they can produce, and determining the observable properties of the resulting events.

Nominally hydrous magmatism on the Moon

PubMed Central

McCubbin, Francis M.; Steele, Andrew; Hauri, Erik H.; Nekvasil, Hanna; Yamashita, Shigeru; Hemley, Russell J.

2010-01-01

For the past 40 years, the Moon has been described as nearly devoid of indigenous water; however, evidence for water both on the lunar surface and within the lunar interior have recently emerged, calling into question this long-standing lunar dogma. In the present study, hydroxyl (as well as fluoride and chloride) was analyzed by secondary ion mass spectrometry in apatite [Ca5(PO4)3(F,Cl,OH)] from three different lunar samples in order to obtain quantitative constraints on the abundance of water in the lunar interior. This work confirms that hundreds to thousands of ppm water (of the structural form hydroxyl) is present in apatite from the Moon. Moreover, two of the studied samples likely had water preserved from magmatic processes, which would qualify the water as being indigenous to the Moon. The presence of hydroxyl in apatite from a number of different types of lunar rocks indicates that water may be ubiquitous within the lunar interior, potentially as early as the time of lunar formation. The water contents analyzed for the lunar apatite indicate minimum water contents of their lunar source region to range from 64 ppb to 5 ppm H2O. This lower limit range of water contents is at least two orders of magnitude greater than the previously reported value for the bulk Moon, and the actual source region water contents could be significantly higher. PMID:20547878

Searching for New Spin- and Velocity-Dependent Interactions by Spin Relaxation of Polarized ^{3}He Gas.

PubMed

Yan, H; Sun, G A; Peng, S M; Zhang, Y; Fu, C; Guo, H; Liu, B Q

2015-10-30

We have constrained possible new interactions which produce nonrelativistic potentials between polarized neutrons and unpolarized matter proportional to ασ[over →]·v[over →] where σ[over →] is the neutron spin and v[over →] is the relative velocity. We use existing data from laboratory measurements on the very long T_{1} and T_{2} spin relaxation times of polarized ^{3}He gas in glass cells. Using the best available measured T_{2} of polarized ^{3}He gas atoms as the polarized source and the Earth as an unpolarized source, we obtain constraints on two new interactions. We present a new experimental upper bound on possible vector-axial-vector (V_{VA}) type interactions for ranges between 1 and 10^{8} m. In combination with previous results, we set the most stringent experiment limits on g_{V}g_{A} ranging from ~μm to ~10^{8} m. We also report what is to our knowledge the first experimental upper limit on the possible torsion fields induced by the Earth on its surface. Dedicated experiments could further improve these bounds by a factor of ~100. Our method of analysis also makes it possible to probe many velocity dependent interactions which depend on the spins of both neutrons and other particles which have never been searched for before experimentally.

Nominally hydrous magmatism on the Moon.

PubMed

McCubbin, Francis M; Steele, Andrew; Hauri, Erik H; Nekvasil, Hanna; Yamashita, Shigeru; Hemley, Russell J

2010-06-22

For the past 40 years, the Moon has been described as nearly devoid of indigenous water; however, evidence for water both on the lunar surface and within the lunar interior have recently emerged, calling into question this long-standing lunar dogma. In the present study, hydroxyl (as well as fluoride and chloride) was analyzed by secondary ion mass spectrometry in apatite [Ca(5)(PO(4))(3)(F,Cl,OH)] from three different lunar samples in order to obtain quantitative constraints on the abundance of water in the lunar interior. This work confirms that hundreds to thousands of ppm water (of the structural form hydroxyl) is present in apatite from the Moon. Moreover, two of the studied samples likely had water preserved from magmatic processes, which would qualify the water as being indigenous to the Moon. The presence of hydroxyl in apatite from a number of different types of lunar rocks indicates that water may be ubiquitous within the lunar interior, potentially as early as the time of lunar formation. The water contents analyzed for the lunar apatite indicate minimum water contents of their lunar source region to range from 64 ppb to 5 ppm H(2)O. This lower limit range of water contents is at least two orders of magnitude greater than the previously reported value for the bulk Moon, and the actual source region water contents could be significantly higher.

Evaluation of Ground-Water and Boron Sources by Use of Boron Stable-Isotope Ratios, Tritium, and Selected Water-Chemistry Constituents near Beverly Shores, Northwestern Indiana, 2004

USGS Publications Warehouse

Buszka, Paul M.; Fitzpatrick, John A.; Watson, Lee R.; Kay, Robert T.

2007-01-01

Concentrations of boron greater than the U.S. Environmental Protection Agency (USEPA) 900 ?g/L removal action level (RAL) standard were detected in water sampled by the USEPA in 2004 from three domestic wells near Beverly Shores, Indiana. The RAL regulates only human-affected concentrations of a constituent. A lack of well logs and screened depth information precluded identification of whether water from sampled wells, and their boron sources, were from human-affected or natural sources in the surficial aquifer, or associated with a previously defined natural, confined aquifer source of boron from the subtill or basal sand aquifers. A geochemically-based classification of the source of boron in ground water could potentially determine the similarity of boron to known sources or mixtures between known sources, or classify whether the relative age of the ground water predated the potential sources of contamination. The U.S. Geological Survey (USGS), in cooperation with the USEPA, investigated the use of a geochemical method that applied boron stable isotopes, and concentrations of boron, tritium, and other constituents to distinguish between natural and human-affected sources of boron in ground water and thereby determine if the RAL was applicable to the situation. Boron stable-isotope ratios and concentrations of boron in 17 ground-water samples and tritium concentrations in 9 ground-water samples collected in 2004 were used to identify geochemical differences between potential sources of boron in ground water near Beverly Shores, Indiana. Boron and d11B analyses for this investigation were made on unacidified samples to assure consistency of the result with unacidified analyses of d11B values from other investigations. Potential sources of boron included surficial-aquifer water affected by coal-combustion products (CCP) or domestic-wastewater, upward discharge of ground water from confined aquifers, and unaffected water from the surficial aquifer that was distant from human-affected boron sources. Boron concentrations in potential ground-water sources of boron were largest (15,700 to 24,400 ?g/L) in samples of CCP-affected surficial aquifer water from four wells at a CCP landfill and smallest (27 to 63 ?g/L) in three wells in the surficial aquifer that were distant from human-affected boron sources. Boron concentrations in water from the basal sand aquifer ranged from 656 ?g/L to 1,800 ?g/L. Boron concentrations in water from three domestic-wastewater-affected surficial aquifer wells ranged from 84 to 387 ?g/L. Among the representative ground-water samples, boron concentrations from all four samples of CCP-affected surficial aquifer water and four of five samples of water from the basal sand aquifer had concentrations greater than the RAL. A comparison of boron concentrations in acid-preserved and unacidified samples indicated that boron concentrations reported for this investigation may be from about 11 to 16 percent less than would be reported in a standard analysis of an acidified sample. The stable isotope boron-11 was most enriched in comparison to boron-10 in ground water from a confined aquifer, the basal sand aquifer (d11B, 24.6 to 34.0 per mil, five samples); it was most depleted in CCP-affected water from the surficial aquifer (d11B, 0.1 to 6.6 per mil, four samples). Domestic-wastewater-affected water from the surficial aquifer (d11B, 8.7 to 11.7 per mil, four samples) was enriched in boron-11, in comparison to individual samples of a borax detergent additive and a detergent with perborate bleach; it was intermediate in composition between basal sand aquifer water and CCP-affected water from the surficial aquifer. The similarity between a ground-water sample from the surficial aquifer and a hypothetical mixture of unaffected surficial aquifer and basal sand aquifer waters indicates the potential for long-term upward discharge of ground water into the surficial aquifer from one or more confined aquifers. Est

Tracing the source of difficult to settle fine particles which cause turbidity in the Hitotsuse Reservoir, Japan.

PubMed

Murakami, Toshiki; Suzuki, Yoshihiro; Oishi, Hiroyuki; Ito, Kenichi; Nakao, Toshio

2013-05-15

A unique method to trace the source of "difficult-to-settle fine particles," which are a causative factor of long-term turbidity in reservoirs was developed. This method is characterized by cluster analysis of XRD (X-ray diffraction) data and homology comparison of major component compositions between "difficult-to-settle fine particles" contained in landslide soil samples taken from the upstream of a dam, and suspended "long-term turbid water particles" in the reservoir, which is subject to long-term turbidity. The experiment carried out to validate the proposed method, demonstrated a high possibility of being able to make an almost identical match between "difficult-to-settle fine particles" taken from landslide soils at specific locations and "long-term turbid water particles" taken from a reservoir. This method has the potential to determine substances causing long-term turbidity and the locations of soils from which those substances came. Appropriate countermeasures can then be taken at those specific locations. Copyright © 2013 Elsevier Ltd. All rights reserved.

The use of long-chain alkylbenzenes and alkyltoluenes for fingerprinting marine oil wastes.

PubMed

Albaigés, Joan; Jimenez, Núria; Arcos, Altamira; Dominguez, Carmen; Bayona, Josep M

2013-04-01

Petroleum long-chain alkylbenzenes and alkyltoluenes are characterized and used for chemical fingerprinting of marine oil spills. Their distributions, extending from C10 to C35 can be used for a general oil type classification. Moreover, the relative distributions of specific components, namely the 3-methyl and 2-methyl-1-alkylbenzenes (m- and o-isomers), and the aryl isoprenoid 1-methyl-3-phytanylbenzene, are proposed as diagnostic markers for source identification. This approach has been exemplified in two case studies involving the spill of bilge oils, where a preliminary screening of the potential source was obtained. Copyright © 2012 Elsevier Ltd. All rights reserved.

Temporally delineated sources of major chemical species in high Arctic snow

NASA Astrophysics Data System (ADS)

Macdonald, Katrina M.; Sharma, Sangeeta; Toom, Desiree; Chivulescu, Alina; Platt, Andrew; Elsasser, Mike; Huang, Lin; Leaitch, Richard; Chellman, Nathan; McConnell, Joseph R.; Bozem, Heiko; Kunkel, Daniel; Duan Lei, Ying; Jeong, Cheol-Heon; Abbatt, Jonathan P. D.; Evans, Greg J.

2018-03-01

Long-range transport of aerosol from lower latitudes to the high Arctic may be a significant contributor to climate forcing in the Arctic. To identify the sources of key contaminants entering the Canadian High Arctic an intensive campaign of snow sampling was completed at Alert, Nunavut, from September 2014 to June 2015. Fresh snow samples collected every few days were analyzed for black carbon, major ions, and metals, and this rich data set provided an opportunity for a temporally refined source apportionment of snow composition via positive matrix factorization (PMF) in conjunction with FLEXPART (FLEXible PARTicle dispersion model) potential emission sensitivity analysis. Seven source factors were identified: sea salt, crustal metals, black carbon, carboxylic acids, nitrate, non-crustal metals, and sulfate. The sea salt and crustal factors showed good agreement with expected composition and primarily northern sources. High loadings of V and Se onto Factor 2, crustal metals, was consistent with expected elemental ratios, implying these metals were not primarily anthropogenic in origin. Factor 3, black carbon, was an acidic factor dominated by black carbon but with some sulfate contribution over the winter-haze season. The lack of K+ associated with this factor, a Eurasian source, and limited known forest fire events coincident with this factor's peak suggested a predominantly anthropogenic combustion source. Factor 4, carboxylic acids, was dominated by formate and acetate with a moderate correlation to available sunlight and an oceanic and North American source. A robust identification of this factor was not possible; however, atmospheric photochemical reactions, ocean microlayer reaction, and biomass burning were explored as potential contributors. Factor 5, nitrate, was an acidic factor dominated by NO3-, with a likely Eurasian source and mid-winter peak. The isolation of NO3- on a separate factor may reflect its complex atmospheric processing, though the associated source region suggests possibly anthropogenic precursors. Factor 6, non-crustal metals, showed heightened loadings of Sb, Pb, and As, and correlation with other metals traditionally associated with industrial activities. Similar to Factor 3 and 5, this factor appeared to be largely Eurasian in origin. Factor 7, sulfate, was dominated by SO42- and MS with a fall peak and high acidity. Coincident volcanic activity and northern source regions may suggest a processed SO2 source of this factor.

5 CFR 2635.703 - Use of nonpublic information.

Code of Federal Regulations, 2013 CFR

2013-01-01

... source selection team assigned to review the proposals submitted by several companies in response to an Army solicitation for spare parts. As a member of the evaluation team, the employee has access to... newspaper reporter nonpublic information about long-range plans to build a particular dam. ...

5 CFR 2635.703 - Use of nonpublic information.

Code of Federal Regulations, 2012 CFR

2012-01-01

... source selection team assigned to review the proposals submitted by several companies in response to an Army solicitation for spare parts. As a member of the evaluation team, the employee has access to... newspaper reporter nonpublic information about long-range plans to build a particular dam. ...

5 CFR 2635.703 - Use of nonpublic information.

Code of Federal Regulations, 2014 CFR

2014-01-01

... source selection team assigned to review the proposals submitted by several companies in response to an Army solicitation for spare parts. As a member of the evaluation team, the employee has access to... newspaper reporter nonpublic information about long-range plans to build a particular dam. ...

Source Characterization of Underground Explosions from Combined Regional Moment Tensor and First-Motion Analysis

DOE PAGES

Chiang, Andrea; Dreger, Douglas S.; Ford, Sean R.; ...

2014-07-08

Here in this study, we investigate the 14 September 1988 U.S.–Soviet Joint Verification Experiment nuclear test at the Semipalatinsk test site in eastern Kazakhstan and two nuclear explosions conducted less than 10 years later at the Chinese Lop Nor test site. These events were very sparsely recorded by stations located within 1600 km, and in each case only three or four stations were available in the regional distance range. We have utilized a regional distance seismic waveform method fitting long-period, complete, three-component waveforms jointly with first-motion observations from regional stations and teleseismic arrays. The combination of long-period waveforms and first-motionmore » observations provides a unique discrimination of these sparsely recorded events in the context of the Hudson et al. (1989) source-type diagram. We demonstrate through a series of jackknife tests and sensitivity analyses that the source type of the explosions is well constrained. One event, a 1996 Lop Nor shaft explosion, displays large Love waves and possibly reversed Rayleigh waves at one station, indicative of a large F-factor. We show the combination of long-period waveforms and P-wave first motions are able to discriminate this event as explosion-like and distinct from earthquakes and collapses. We further demonstrate the behavior of network sensitivity solutions for models of tectonic release and spall-based tensile damage over a range of F-factors and K-factors.« less

Source Characterization of Underground Explosions from Combined Regional Moment Tensor and First-Motion Analysis

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

Chiang, Andrea; Dreger, Douglas S.; Ford, Sean R.

Here in this study, we investigate the 14 September 1988 U.S.–Soviet Joint Verification Experiment nuclear test at the Semipalatinsk test site in eastern Kazakhstan and two nuclear explosions conducted less than 10 years later at the Chinese Lop Nor test site. These events were very sparsely recorded by stations located within 1600 km, and in each case only three or four stations were available in the regional distance range. We have utilized a regional distance seismic waveform method fitting long-period, complete, three-component waveforms jointly with first-motion observations from regional stations and teleseismic arrays. The combination of long-period waveforms and first-motionmore » observations provides a unique discrimination of these sparsely recorded events in the context of the Hudson et al. (1989) source-type diagram. We demonstrate through a series of jackknife tests and sensitivity analyses that the source type of the explosions is well constrained. One event, a 1996 Lop Nor shaft explosion, displays large Love waves and possibly reversed Rayleigh waves at one station, indicative of a large F-factor. We show the combination of long-period waveforms and P-wave first motions are able to discriminate this event as explosion-like and distinct from earthquakes and collapses. We further demonstrate the behavior of network sensitivity solutions for models of tectonic release and spall-based tensile damage over a range of F-factors and K-factors.« less

The long range transport of birch (Betula) pollen from Poland and Germany causes significant pre-season concentrations in Denmark

NASA Astrophysics Data System (ADS)

Ambelas Skjoth, C.; Sommer, J.; Stach, A.; Smith, M.; Brandt, J.; Christensen, J. H.; Frohn, L. M.; Geels, C.; Hansen, K. M.; Hedegaard, G. B.

2009-04-01

In Denmark, where birch pollen is considered to be among the most important allergenic pollen, about one million people suffer from seasonal allergic rhinitis. In Denmark, the official reported pollen forecast is based on the daily weather forecast, the pollen calendar and local 24-h measurements. Birch pollen has the potential for long-range transport but the present Danish pollen forecast does not account for birch pollen being transported into the country from distant sources.. Long-range transport episodes are intermittent and often out of the main pollen season, where individuals in general will be medically unprotected. Here we use an integrated approach to investigate whether or not Denmark receives significant quantities of birch pollen from Poland and Germany before local trees start to flower. In 2006 we used a combination of phenological observations and pollen measurements in Poland (Poznań) and Denmark (Copenhagen). Seasonal and diurnal variations in birch pollen measurement from Copenhagen (2000-2006) were examined with the aim of identifying pre-seasonal episodes originating from long-range transport. The 2.5% accumulation method was used for identifying start of season. If daily pollen counts exceeded 30 grains/m3 either before the local flowering season began or on the actual start day, the episode was chosen for investigation with back trajectory analysis. A birch forest inventory for Northern Europe was produced and implemented in DEHM-Pollen along with a simple unified pollen release model SUPREME to investigate the 2006 campaign in detail. In 2006, full flowering took place in Poznan between 20th and 28th of April and daily concentrations varied between 739 and 2169 grains/m3. In Copenhagen phenological observations showed that local flowering was initiated the 2nd of May. In Copenhagen several episodes with pollen concentrations at 108, 244 and 41 grains/m3 were recorded the 23rd, 26th and 27th of April, respectively. Back-trajectory analysis showed that for those tree dates the origin of the air masses was Poland including the Poznan region. 11 possible pre-seasonal long-range transport episodes in 2000-2006 were identified during analyses of the measured pollen data. All possible long-range transport episodes were investigated with back trajectories. In all investigated episodes, the air masses Copenhagen originated directly from either Germany or Poland. The model results from DEHM pollen for 2006 show several episodes in Copenhagen with high pollen concentration for the 23rd - 24th and 26th - 27th of April, respectively. These pre-seasonal peaks in 2006 were modelled well with respect to timing and magnitude. During this period the SUPREME model only predicts birch pollen emission south of Denmark. Long-range transport episodes of birch pollen from Poland and Germany has happened almost every year since 2000 and it is therefore likely that this is a general pattern. It is shown that DEHM-Pollen for the year 2006 is able to simulate pre-seasonal pollen concentrations in Denmark, where key components include a well calibrated emission model and emission inventory. Furthermore, all model components are prepared for full implementation in the THOR air pollution and forecasting system. During pre-seasonal, pollen allergy patients are in general medically unprotected. Such episodes will therefore have a full impact with respect to allergic reactions among the allergy patients. The use of the integrated approach improves knowledge of such episodes. Furthermore, an implementation of DEHM-Pollen in the THOR system has the potential to provide early warnings of severe pre-seasonal pollen episodes to the entire Danish population, by forecasting how far and how severe a possible pre-seasonal birch pollen cloud will progress into Denmark.

The long-range transport of aerosol particles over the north Atlantic Ocean

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

Ellis, W.G. Jr.

1992-01-01

As part of the Atmosphere/Ocean Chemistry Experiment (AE-ROCE), daily aerosol samples were collected at Bermuda and Barbados. In addition, gas-phase [sup 222]Rn concentrations were analyzed hourly from July 1991 to June 1992. Isentropic analyses, isentropic trajectories, and non-isentropic tranjectories were used to understand the long-range transport of these substances. In particular, the sources of selenium (Se) at Bermuda and Barbados, the transport of aluminum (Al) at Barbados, and the effect of atmospheric stability on radionuclides at Bermuda, were investigated. At Bermuda, approximately 55% of the aerosol Se came from anthropogenic sources located in North America, while the remainder appeared tomore » be from a marine biogenic sources. At Barbados, 60-80% of the Se was attributed to marine biogenic sources. At Barbados, the transport of Al from northern Africa to Barbados was modeled using a vertical interpolation of wind fields. Stoke's law of gravitational settling was used to parameterize the vertical motion. The trajectories using Stokes's law more more accurately predicted the source region of the Al compared to low-level isentropic trajectories. The affect of tropospheric stability on the concentrations of [sup 222]Rn, [sup 210]Pb, and [sup 7]Be sampled at Bermuda was investigated. [sup 7]Be has an upper tropospheric source, while [sup 222]Rn and [sup 210]Pb both have a continental source. The stability of the lower troposphere was calculated based on the relative separation of isentropic surfaces over North America. The results showed that this measure of stability was able to resolve the seasonal effect of stability on these radionuclides, but was not a quantitative predictor.« less

Back-bombardment compensation in microwave thermionic electron guns

NASA Astrophysics Data System (ADS)

Kowalczyk, Jeremy M. D.; Madey, John M. J.

2014-12-01

The development of capable, reliable, and cost-effective compact electron beam sources remains a long-standing objective of the efforts to develop the accelerator systems needed for on-site research and industrial applications ranging from electron beam welding to high performance x-ray and gamma ray light sources for element-resolved microanalysis and national security. The need in these applications for simplicity, reliability, and low cost has emphasized solutions compatible with the use of the long established and commercially available pulsed microwave rf sources and L-, S- or X-band linear accelerators. Thermionic microwave electron guns have proven to be one successful approach to the development of the electron sources for these systems providing high macropulse average current beams with picosecond pulse lengths and good emittance out to macropulse lengths of 4-5 microseconds. But longer macropulse lengths are now needed for use in inverse-Compton x-ray sources and other emerging applications. We describe in this paper our approach to extending the usable macropulse current and pulse length of these guns through the use of thermal diffusion to compensate for the increase in cathode surface temperature due to back-bombardment.

Analysis and prediction of ocean swell using instrumented buoys

NASA Technical Reports Server (NTRS)

Mettlach, Theodore; Wang, David; Wittmann, Paul

1994-01-01

During the period 20-23 September 1990, the remnants of Supertyphoon Flo moved into the central North Pacific Ocean with sustained wind speeds of 28 m/s. The strong wind and large fetch area associated with this storm generated long-period swell that propagated to the west coast of North America. National Data Buoy Center moored-buoy stations, located in a network that ranged from the Gulf of Alaska to the California Bight, provided wave spectral estimates of the swell from this storm. The greatest dominant wave periods measured were approximately 20-25 s, and significant wave heights measured ranged from 3 to 8 m. Wave spectra from an array of three nondirectional buoys are used to find the source of the long-period swell. Directional wave spectra from a heave-pitch-roll buoy are also used to make an independent estimate of the source of the swell. The ridge-line method, using time-frequency contour plots of wave spectral energy density, is used to determine the time of swell generation, which is used with the appropriate surface pressure analysis to infer the swell generation area. The diagnosed sources of the swell are also compared with nowcasts from the Global Spectral Ocean Wave Model of the Fleet Numerical Oceanography Center. A simple method of predicting the propagation of ocean swell, by applying a simple kinematic model of wave propagation to the estimated point and time source, is demonstrated.

Imputation of missing genotypes from sparse to high density using long-range phasing

USDA-ARS?s Scientific Manuscript database

Related individuals share potentially long chromosome segments that trace to a common ancestor. A phasing algorithm (ChromoPhase) that utilizes this characteristic of finite populations was developed to phase large sections of a chromosome. In addition to phasing, ChromoPhase imputes missing genotyp...

Development and application of a long dynamic range nitrous oxide monitoring system.

PubMed

Ward, B G

1985-12-01

The laboratory and field evaluation of a nitrous oxide monitor for an extremely wide range of cumulative exposures are reviewed. The passive sampling behavior and high analyte capacity show it to be useful for short-term and full workweek exposure monitoring. The monitor has application for both area and personnel surveillance. The principal criterion is for an accurate report of exposure time of the monitor. Application of the monitor to real workplace environments--with and without a reference method--demonstrated the ability of workweek monitoring as a valuable and potentially superior way of documenting exposure stress of employees. Environmental factors such as humidity and temperature variation are shown to have acceptably small effects on both short- and long-term exposure data; barometric pressure affects the data in a predictable manner. Paired dosimeters show good agreement in the workplace environment throughout the range of 6-40 cumulative hours of exposure. In both hospital and dental operating suites, work logistics and work group relationships were readily traceable on a week-by-week basis during a continuous weekly monitoring program. Source emissions and appropriate worker and work area exposure relationships were clearly evident, with appropriate reduction of all exposures as a result of an abbreviated work schedule. The ability to effectively track employee and area exposure excursions in an integrated weekly manner leads to a whole series of new applications and concepts of industrial hygiene surveillance. Such approaches could effectively replace the speculative statistical approaches currently in use with actual data on a cost effective basis.

Fate of Polycyclic Aromatic Hydrocarbons in Seawater from the Western Pacific to the Southern Ocean (17.5°N to 69.2°S) and Their Inventories on the Antarctic Shelf.

PubMed

Cai, Minggang; Liu, Mengyang; Hong, Qingquan; Lin, Jing; Huang, Peng; Hong, Jiajun; Wang, Jun; Zhao, Wenlu; Chen, Meng; Cai, Minghong; Ye, Jun

2016-09-06

Semivolatile organic compounds such as polycyclic aromatic hydrocarbons (PAHs) have the potential to reach pristine environments through long-range transport. To investigate the long-range transport of the PAHs and their fate in Antarctic seawater, dissolved PAHs in the surface waters from the western Pacific to the Southern Ocean (17.5°N to 69.2°S), as well as down to 3500 m PAH profiles in Prydz Bay and the adjacent Southern Ocean, were observed during the 27th Chinese National Antarctic Research Expedition in 2010. The concentrations of Σ9PAH in the surface seawater ranged from not detected (ND) to 21 ng L(-1), with a mean of 4.3 ng L(-1); and three-ring PAHs were the most abundant compounds. Samples close to the Australian mainland displayed the highest levels across the cruise. PAHs originated mainly from pyrogenic sources, such as grass, wood, and coal combustion. Vertical profiles of PAHs in Prydz Bay showed a maximum at a depth of 50 m and less variance with depth. In general, we inferred that the water masses as well as the phytoplankton were possible influencing factors on PAH surface-enrichment depth-depletion distribution. Inventory estimation highlighted the contribution of intermediate and deep seawater on storing PAHs in seawater from Prydz Bay, and suggested that climate change rarely shows the rapid release of the PAHs currently stored in the major reservoirs (intermediate and deep seawater).

Who Meets the Contraceptive Needs of Young Women in Sub-Saharan Africa?

PubMed

Radovich, Emma; Dennis, Mardieh L; Wong, Kerry L M; Ali, Moazzam; Lynch, Caroline A; Cleland, John; Owolabi, Onikepe; Lyons-Amos, Mark; Benova, Lenka

2018-03-01

Despite efforts to expand contraceptive access for young people, few studies have considered where young women (age 15-24) in low- and middle-income countries obtain modern contraceptives and how the capacity and content of care of sources used compares with older users. We examined the first source of respondents' current modern contraceptive method using the most recent Demographic and Health Survey since 2000 for 33 sub-Saharan African countries. We classified providers according to sector (public/private) and capacity to provide a range of short- and long-term methods (limited/comprehensive). We also compared the content of care obtained from different providers. Although the public and private sectors were both important sources of family planning (FP), young women (15-24) used more short-term methods obtained from limited-capacity, private providers, compared with older women. The use of long-term methods among young women was low, but among those users, more than 85% reported a public sector source. Older women (25+) were significantly more likely to utilize a comprehensive provider in either sector compared with younger women. Although FP users of all ages reported poor content of care across all providers, young women had even lower content of care. The results suggest that method and provider choice are strongly linked, and recent efforts to increase access to long-term methods among young women may be restricted by where they seek care. Interventions to increase adolescents' access to a range of FP methods and quality counseling should target providers frequently used by young people, including limited-capacity providers in the private sector. Copyright © 2017 The Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Modeling of long range frequency sweeping for energetic particle modes

NASA Astrophysics Data System (ADS)

Nyqvist, R. M.; Breizman, B. N.

2013-04-01

Long range frequency sweeping events are simulated numerically within a one-dimensional, electrostatic bump-on-tail model with fast particle sources and collisions. The numerical solution accounts for fast particle trapping and detrapping in an evolving wave field with a fixed wavelength, and it includes three distinct collisions operators: Drag (dynamical friction on the background electrons), Krook-type collisions, and velocity space diffusion. The effects of particle trapping and diffusion on the evolution of holes and clumps are investigated, and the occurrence of non-monotonic (hooked) frequency sweeping and asymptotically steady holes is discussed. The presented solution constitutes a step towards predictive modeling of frequency sweeping events in more realistic geometries.

Atmospheric CO2 measurements with a 2-μm DIAL instrument

NASA Astrophysics Data System (ADS)

Cadiou, Erwan; Dherbecourt*, Jean-Baptiste; Gorju, Guillaume; Melkonian, Jean-Michel; Godard, Antoine; Pelon, Jacques; Raybaut, Myriam

2018-04-01

We report on ground-based atmospheric concentration measurements of carbon dioxide, using a pulsed direct detection differential absorption lidar operating at 2051 nm. The transmitter is based on a tunable parametric source emitting 10-mJ energy, 10-ns duration Fourier-limited pulses. Range resolved concentration measurements have been carried out on the aerosol back-scattered signal. Cloud signals have been used to get long range integrated-path measurements.

Chemical potential fluctuations in topological insulator (Bi0.5Sb0.5)2Te3-films visualized by photocurrent spectroscopy

NASA Astrophysics Data System (ADS)

Kastl, Christoph; Seifert, Paul; He, Xiaoyue; Wu, Kehui; Li, Yongqing; Holleitner, Alexander

2015-06-01

We investigate the photocurrent properties of the topological insulator (Bi0.5Sb0.5)2Te3 on SrTiO3-substrates. We find reproducible, submicron photocurrent patterns generated by long-range chemical potential fluctuations, occurring predominantly at the topological insulator/substrate interface. We fabricate nano-plowed constrictions which comprise single potential fluctuations. Hereby, we can quantify the magnitude of the disorder potential to be in the meV range. The results further suggest a dominating photo-thermoelectric current generated in the surface states in such nanoscale constrictions.

Water-soluble ions and trace elements in surface snow and their potential source regions across northeastern China

NASA Astrophysics Data System (ADS)

Wang, Xin; Pu, Wei; Zhang, Xueying; Ren, Yong; Huang, Jianping

2015-08-01

We collected 92 snow samples from 13 sites across northeastern China from January 7 to February 15, 2014. The surface snow samples were analyzed for the major water-soluble ions (SO42-, NO3-, F-, Cl-, Na+, K+, Ca2+, Mg2+, and NH4+) and trace element (Al, As, Mn, V, Cd, Cu, Pb, Zn, Fe, Cr, and Ni). The results indicated that the higher concentrations of NO3- and SO42- and the trace elements Zn, Pb, Cd, Ni, and Cu were likely attributable to enhanced local industrial emissions in East Asia especially in China. In addition, snow samples characterized by higher enrichment factors of trace elements (Cu, Cd, As, Zn, Pb) were indicative of an anthropogenic source. Emissions from fossil fuel combustion and biomass burning were likely important contributors to the chemical elements in seasonal snow with long-range transport. On the other hand, the large attribution of K+ appeared in the higher latitude demonstrated that biomass burning was a dominated factor of the chemical species in seasonal snow in the higher latitude of China than that in the lower latitude. Finally, an interannual comparison with the 2010 China snow survey also confirmed the source attributions of chemical speciation in seasonal snow in these regions.

Multifractal behavior of an air pollutant time series and the relevance to the predictability.

PubMed

Dong, Qingli; Wang, Yong; Li, Peizhi

2017-03-01

Compared with the traditional method of detrended fluctuation analysis, which is used to characterize fractal scaling properties and long-range correlations, this research provides new insight into the multifractality and predictability of a nonstationary air pollutant time series using the methods of spectral analysis and multifractal detrended fluctuation analysis. First, the existence of a significant power-law behavior and long-range correlations for such series are verified. Then, by employing shuffling and surrogating procedures and estimating the scaling exponents, the major source of multifractality in these pollutant series is found to be the fat-tailed probability density function. Long-range correlations also partly contribute to the multifractal features. The relationship between the predictability of the pollutant time series and their multifractal nature is then investigated with extended analyses from the quantitative perspective, and it is found that the contribution of the multifractal strength of long-range correlations to the overall multifractal strength can affect the predictability of a pollutant series in a specific region to some extent. The findings of this comprehensive study can help to better understand the mechanisms governing the dynamics of air pollutant series and aid in performing better meteorological assessment and management. Copyright © 2016 Elsevier Ltd. All rights reserved.

Validation of the TOLNet lidars during SCOOP (Southern California Ozone Observation Project)

NASA Astrophysics Data System (ADS)

Leblanc, Thierry; Granados-Munoz, Maria-Jose; Strawbridge, Kevin; Senff, Chris; Langford, Andy; Berkoff, Tim; Gronoff, Guillaume; DeYoung, Russel; Carion, Bill; Chen, G.; Sullivan, John; McGee, Tom; Jonhson, M.; Kuang, S.; Newchurch, Mike

2018-04-01

Five TOLNet lidars participated to a validation campaign at the JPL-Table Mountain Facility, CA in August 2016. All lidars agreed within ±10% of each other and within ±7% of the ozonesondes. Centralized data processing was used to compare the uncertainty budgets. The results highlight the TOLNet potential to address science questions ranging from boundary layer processes to long range transport. TOLNet can now be seen as a robust network for use in field campaigns and long term monitoring.