Science.gov

Sample records for abundant cheap electricity

  1. Cheap electricity from French tides

    NASA Astrophysics Data System (ADS)

    Andre, H.

    1980-02-01

    A tidal power plant built in Saint-Malo, France is examined, and some of the problems that have resulted in recent years are analyzed. These include mechanical problems due to turbine runner-blade seal failure and electrical problems involving electroerosion and structural station difficulties. the effects of tidal power plants on the environment are discussed, and it is noted that all possible side effects of the operations are very limited. Attention is given to the basic requirements for constructing power sites.

  2. A novel scheme for making cheap electricity with nuclear energy

    SciTech Connect

    Pettibone, J.S.

    1991-04-01

    Nuclear fuels should produce cheaper electricity than coal, considering their high specific energy and low cost. To exploit these properties, the scheme proposed here replaces the expensive reactor/steam-turbine system with an engine in which the expansion of a gas heated by a nuclear explosion raises a mass of liquid, thereby producing stored hydraulic energy. This energy could be converted to electricity by hydroelectric generation with water as the working fluid or by magnetohydrodynamic (MHD) generation with molten metal. A rough cost analysis suggests the hydroelectric system could reduce the present cost of electricity by two-thirds, and the MHD system by even more. Such cheap power would make feasible large-scale electrolysis to produce hydrogen and other fuels and chemical raw materials. 2 refs., 1 fig.

  3. Electricity Submetering on the Cheap: Stick-on Electricity Meters

    SciTech Connect

    Lanzisera, Steven; Lorek, Michael; Pister, Kristofer

    2014-08-17

    We demonstrate a low-cost, 21 x 12 mm prototype Stick-on Electricity Meter (SEM) to replace traditional in-circuit-breaker-panel current and voltage sensors for building submetering. A SEM sensor is installed on the external face of a circuit breaker to generate voltage and current signals. This allows for the computation of real and apparent power as well as capturing harmonics created by non-linear loads. The prototype sensor is built using commercially available components, resulting in a production cost of under $10 per SEM. With no highvoltage install work requiring an electrician, home owners or other individuals can install the system in a few minutes with no safety implications. This leads to an installed system cost that is much lower than traditional submetering technology.. Measurement results from lab characterization as well as a real-world residential dwelling installation are presented, verifying the operation of our proposed SEM sensor. The SEM sensor can resolve breaker power levels below 10W, and it can be used to provide data for non-intrusive load monitoring systems at full sample rate.

  4. Is Cheap Labor a Magnet for Capital?

    ERIC Educational Resources Information Center

    Hanson, John R., II

    1995-01-01

    Contends that it is widely believed that cheap labor in poor countries attracts foreign investors. Asserts that historical evidence indicates that past patterns of direct foreign investment in poor countries are inconsistent with the cheap-labor argument. Includes two figures and one table. (CFR)

  5. The end of cheap uranium.

    PubMed

    Dittmar, Michael

    2013-09-01

    Historic data from many countries demonstrate that on average no more than 50-70% of the uranium in a deposit could be mined. An analysis of more recent data from Canada and Australia leads to a mining model with an average deposit extraction lifetime of 10±2 years. This simple model provides an accurate description of the extractable amount of uranium for the recent mining operations. Using this model for all larger existing and planned uranium mines up to 2030, a global uranium mining peak of at most 58±4 ktons around the year 2015 is obtained. Thereafter we predict that uranium mine production will decline to at most 54±5 ktons by 2025 and, with the decline steepening, to at most 41±5 ktons around 2030. This amount will not be sufficient to fuel the existing and planned nuclear power plants during the next 10-20 years. In fact, we find that it will be difficult to avoid supply shortages even under a slow 1%/year worldwide nuclear energy phase-out scenario up to 2025. We thus suggest that a worldwide nuclear energy phase-out is in order. If such a slow global phase-out is not voluntarily effected, the end of the present cheap uranium supply situation will be unavoidable. The result will be that some countries will simply be unable to afford sufficient uranium fuel at that point, which implies involuntary and perhaps chaotic nuclear phase-outs in those countries involving brownouts, blackouts, and worse.

  6. Hydroelectric power provides a cheap source of electricity with few carbon emissions. Yet, reservoirs are not operated sustainably, which we define as meeting societal needs for water and power while protecting long-term health of the river ecosystem. Reservoirs that generate hydropower are typically operated with the goal of maximizing energy reve

    SciTech Connect

    Jager, Yetta; Smith, Brennan T

    2008-02-01

    Hydroelectric power provides a cheap source of electricity with few carbon emissions. Yet, reservoirs are not operated sustainably, which we define as meeting societal needs for water and power while protecting long-term health of the river ecosystem. Reservoirs that generate hydropower are typically operated with the goal of maximizing energy revenue, while meeting other legal water requirements. Reservoir optimization schemes used in practice do not seek flow regimes that maximize aquatic ecosystem health. Here, we review optimization studies that considered environmental goals in one of three approaches. The first approach seeks flow regimes that maximize hydropower generation, while satisfying legal requirements, including environmental (or minimum) flows. Solutions from this approach are often used in practice to operate hydropower projects. In the second approach, flow releases from a dam are timed to meet water quality constraints on dissolved oxygen (DO), temperature and nutrients. In the third approach, flow releases are timed to improve the health of fish populations. We conclude by suggesting three steps for bringing multi-objective reservoir operation closer to the goal of ecological sustainability: (1) conduct research to identify which features of flow variation are essential for river health and to quantify these relationships, (2) develop valuation methods to assess the total value of river health and (3) develop optimal control softwares that combine water balance modelling with models that predict ecosystem responses to flow.

  7. Banishing Asthma-Inducing Mice Allergens on The Cheap

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_163963.html Banishing Asthma-Inducing Mice Allergens on the Cheap Do-it- ... pest management may not be needed to control asthma in kids with a mouse allergy, researchers say. ...

  8. A closer look at ‘Cheap White’ cigarettes

    PubMed Central

    Ross, Hana; Vellios, Nicole; Clegg Smith, Katherine; Ferguson, Jacqueline; Cohen, Joanna E

    2016-01-01

    Background Given the prominence of Cheap Whites in illicit tobacco discussions, we examined various definitions, market presence, brand proliferation, manufacturers, production locations, trademark ownership, prices and compliance with tax stamp and warning labels. Methods Data from peer-reviewed and grey literature, newspapers, trademark registries, governments/international organisation reports, and the tobacco industry were contrasted with two visual legal requirements (tax stamps and warning labels) and prices from the Tobacco Pack Surveillance System (TPackSS). Results Multiple sources identified 82 Cheap White brands and 53 manufacturers operating at least 82 production facilities. One-third of these manufacturers are in the free zones of Russia, Cyprus and the UAE. Two-thirds of the 37 Cheap White brands in the TPackSS had neither the correct health warning nor the required tax stamp in at least one country where they were purchased. Cheap Whites are on average less expensive than all other brands, but the price gap is often not as large as anecdotally reported. The cheapest Cheap White cigarettes purchased in one of the TPackSS countries irrespective of the presence of legal signs were still more expensive than the least expensive other brands satisfying both legal requirements. Conclusions We confirmed that many Cheap White brands do not comply with the legal requirements in countries where they are sold, but also found that some of these cigarettes appear to be sold legally even outside their country of origin. The presence of untaxed Cheap Whites undermines tobacco tax policies, while the availability of legal cheap cigarettes is a public health concern. PMID:26418617

  9. Robust trajectory tracking: differential game/cheap control approach

    NASA Astrophysics Data System (ADS)

    Turetsky, Vladimir; Glizer, Valery Y.; Shinar, Josef

    2014-11-01

    A robust trajectory tracking problem is treated in the framework of a zero-sum linear-quadratic differential game of a general type. For the cheap control version of this game, a novel solvability condition is derived. The sufficient condition, guaranteeing that the tracking problem is solved by the optimal strategy of the minimiser in the cheap control game, is established. The boundedness of the time realisations of this strategy is analysed. An illustrative example is presented.

  10. A Practical and Cheap Circuit for ECG Sensing and Heart Frequency Alarm

    NASA Astrophysics Data System (ADS)

    Aviña-Cervantes, J. G.; González-García, A. E.; Alvarado-Méndez, E.; Trejo-Durán, M.; Torres-Cisneros, M.; Sánchez-Yáñez, R.; Ayala-Ramírez, V.

    2006-09-01

    A practical electronic circuit for ECG sensing, using high gain instrumentation amplifiers, a PIC microcontroller and two electrodes is presented. It allows to identify and to amplify a well-delimited ECG signal for a further wave analysis, and using a zero crossing detector a heart frequency detector is also implemented. By the moment, the conventional electrocardiogram (ECG) configurations making use of separate electrical connections to the arms and legs (bipolar limb lead 1) is exploited. This device is a practical and cheap way to monitoring ECG signal and some heart anomalies (e.g., arrhythmias, tachycardia) that can be used in a network to communicate anytime with a far health supervisor.

  11. A Theory of Cheap Control in Embodied Systems.

    PubMed

    Montúfar, Guido; Ghazi-Zahedi, Keyan; Ay, Nihat

    2015-09-01

    We present a framework for designing cheap control architectures of embodied agents. Our derivation is guided by the classical problem of universal approximation, whereby we explore the possibility of exploiting the agent's embodiment for a new and more efficient universal approximation of behaviors generated by sensorimotor control. This embodied universal approximation is compared with the classical non-embodied universal approximation. To exemplify our approach, we present a detailed quantitative case study for policy models defined in terms of conditional restricted Boltzmann machines. In contrast to non-embodied universal approximation, which requires an exponential number of parameters, in the embodied setting we are able to generate all possible behaviors with a drastically smaller model, thus obtaining cheap universal approximation. We test and corroborate the theory experimentally with a six-legged walking machine. The experiments indicate that the controller complexity predicted by our theory is close to the minimal sufficient value, which means that the theory has direct practical implications.

  12. Cheap Oil and the Impact on Rebuilding Syria

    DTIC Science & Technology

    2015-10-30

    Syrian energy infrastructure will not be cost effective in the current oil pricing environment. I will present a quick overview of oil’s historic role...future. This paper argues that rebuilding the Syrian energy infrastructure will not be cost effective in the current oil pricing environment. I will...of economic revenue outside of the energy sector. The oil exporters predicted to be hit the hardest by cheap oil prices over the next couple years

  13. Cheap carbon sorbents produced from lignite by catalytic pyrolysis

    SciTech Connect

    Kuznetsov, B.N.; Schchipko, M.L.

    1995-12-01

    Some data are presented describing the new technology of carbon sorbent production from powdered lignite in the installation with fluidized bed of catalyst. It was shown the different types of char products with extended pore structure and high sorption ability can be produced from cheap and accessible lignite of Kansk-Achinsk coal pit in pilot installation with fluidized bed of Al-Cu-Cr oxide catalyst or catalytically active slag materials. In comparison with the conventional technologies of pyrolysis the catalytic pyrolysis allows to increase by 3-5 times the process productivity and to decrease significantly the formation of harmful compounds. The latter is accomplished by complete oxidation of gaseous pyrolysis products in the presence of catalysts and by avoiding the formation of pyrolysis tars - the source of cancerogenic compounds. The technology of cheap powdered sorbent production from lignites makes possible to obtain from lignite during the time of pyrolysis only a few seconds char products with porosity up to 0.6 cm{sup 3} /g, and specific surface area more than 400 m{sup 3} /g. Some methods of powdered chars molding into carbon materials with the different shape were proved for producing of firmness sorbents. Cheap carbon sorbents obtained by thermocatalytic pyrolysis can be successfully used in purification of different industrial pollutants as one-time sorbent or as adsorbents of long-term application with periodic regeneration.

  14. Cheap Talk with Multiple Strategically Interacting Audiences: An Experimental Study

    PubMed Central

    Li, Xinyu; Peeters, Ronald

    2016-01-01

    We consider a cheap-talk setting that mimics the situation where an incumbent firm (the sender) is endowed with incentives to understate the true size of the market demand to two potential entrants (the receivers). Although our experimental data reveals that the senders’ messages convey truthful information and this is picked up by the receivers, this overcommunication (relative to standard theoretical prediction) does not enhance efficient entry levels (and payoffs) to beyond what can be achieved without communication. The reason is that receivers fail to optimally translate the information received in their entry decision, possibly due to overcautiousness. PMID:27695082

  15. Conception of a cheap infrared camera using a Fresnel lens

    NASA Astrophysics Data System (ADS)

    Grulois, Tatiana; Druart, Guillaume; Guérineau, Nicolas; Crastes, Arnaud; Sauer, Hervé; Chavel, Pierre

    2014-09-01

    Today huge efforts are made in the research and industrial areas to design compact and cheap uncooled infrared optical systems for low-cost imagery applications. Indeed, infrared cameras are currently too expensive to be widespread. If we manage to cut their cost, we expect to open new types of markets. In this paper, we will present the cheap broadband microimager we have designed. It operates in the long-wavelength infrared range and uses only one silicon lens at a minimal cost for the manufacturing process. Our concept is based on the use of a thin optics. Therefore inexpensive unconventional materials can be used because some absorption can be tolerated. Our imager uses a thin Fresnel lens. Up to now, Fresnel lenses have not been used for broadband imagery applications because of their disastrous chromatic properties. However, we show that working in a high diffraction order can significantly reduce chromatism. A prototype has been made and the performance of our camera will be discussed. Its characterization has been carried out in terms of modulation transfer function (MTF) and noise equivalent temperature difference (NETD). Finally, experimental images will be presented.

  16. High performance organic transistors on cheap, commercial substrates

    NASA Astrophysics Data System (ADS)

    Majewski, L. A.; Schroeder, R.; Voigt, M.; Grell, M.

    2004-12-01

    We present here our latest results on high quality gate insulators for organic electronics. Ultra-thin films of n-octadecyltrichlorosilane-treated, anodized aluminium (Al) grown onto flexible, Al-sputtered polyester substrates combine low cost and manufacture under ambient conditions with excellent performance characteristics (negligible leakage and hysteresis, 400 nF cm-2 capacitance). With pentacene as organic semiconductor, we present organic transistors with inverse subthreshold slope of approximately 200 mV dec-1, threshold of the order of -2 V and >105 on/off ratio. The subthreshold behaviour is significantly better than for transistors with pentacene deposited onto a gate insulator optimized for high mobility. Above the threshold, the higher capacitance compensates for the somewhat lower mobility. Crucially, the cheap, sputtered Al-on-polyester films resulted in transistors that were as good as transistors fabricated on the same substrate with evaporated Al.

  17. Electricity

    SciTech Connect

    Sims, B.

    1983-01-01

    Historical aspects of electricity are reviewed with individual articles on hydroelectric dams, coal-burning power plants, nuclear power plants, electricity distribution, and the energy future. A glossary is included. (PSB)

  18. Voltage-Gated Na+ Channel Isoforms and Their mRNA Expression Levels and Protein Abundance in Three Electric Organs and the Skeletal Muscle of the Electric Eel Electrophorus electricus

    PubMed Central

    Hiong, Kum C.; Boo, Mel V.; Wong, Wai P.; Chew, Shit F.

    2016-01-01

    This study aimed to obtain the coding cDNA sequences of voltage-gated Na+ channel (scn) α-subunit (scna) and β-subunit (scnb) isoforms from, and to quantify their transcript levels in, the main electric organ (EO), Hunter’s EO, Sach’s EO and the skeletal muscle (SM) of the electric eel, Electrophorus electricus, which can generate both high and low voltage electric organ discharges (EODs). The full coding sequences of two scna (scn4aa and scn4ab) and three scnb (scn1b, scn2b and scn4b) were identified for the first time (except scn4aa) in E. electricus. In adult fish, the scn4aa transcript level was the highest in the main EO and the lowest in the Sach’s EO, indicating that it might play an important role in generating high voltage EODs. For scn4ab/Scn4ab, the transcript and protein levels were unexpectedly high in the EOs, with expression levels in the main EO and the Hunter’s EO comparable to those of scn4aa. As the key domains affecting the properties of the channel were mostly conserved between Scn4aa and Scn4ab, Scn4ab might play a role in electrogenesis. Concerning scnb, the transcript level of scn4b was much higher than those of scn1b and scn2b in the EOs and the SM. While the transcript level of scn4b was the highest in the main EO, protein abundance of Scn4b was the highest in the SM. Taken together, it is unlikely that Scna could function independently to generate EODs in the EOs as previously suggested. It is probable that different combinations of Scn4aa/Scn4ab and various Scnb isoforms in the three EOs account for the differences in EODs produced in E. electricus. In general, the transcript levels of various scn isoforms in the EOs and the SM were much higher in adult than in juvenile, and the three EOs of the juvenile fish could be functionally indistinct. PMID:27907137

  19. Teaching Old Dogs New Tricks: The Luxury of Digital Abundance

    ERIC Educational Resources Information Center

    O'Brien, David; Scharber, Cassandra

    2010-01-01

    Today we thrive on an abundance of relatively cheap computing power and have the luxury of wasting most of it. It is quickly becoming not only possible but also financially sound, for educators to significantly complement, supplement, or even replace traditional print curricula with digital print and media, online curricula and websites, and…

  20. Synthesis of mesoporous zeolite single crystals with cheap porogens

    SciTech Connect

    Tao Haixiang; Li Changlin; Ren Jiawen; Wang Yanqin; Lu Guanzhong

    2011-07-15

    Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals have been successfully synthesized by adding soluble starch or sodium carboxymethyl cellulose (CMC) to a conventional zeolite synthesis system. The obtained samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen sorption analysis, {sup 27}Al magic angle spinning nuclear magnetic resonance ({sup 27}Al MAS NMR), temperature-programmed desorption of ammonia (NH{sub 3}-TPD) and ultraviolet-visible spectroscopy (UV-vis). The SEM images clearly show that all zeolite crystals possess the similar morphology with particle size of about 300 nm, the TEM images reveal that irregular intracrystal pores are randomly distributed in the whole crystal. {sup 27}Al MAS NMR spectra indicate that nearly all of the Al atoms are in tetrahedral co-ordination in ZSM-5, UV-vis spectra confirm that nearly all of titanium atoms are incorporated into the framework of TS-1. The catalytic activity of meso-ZSM-5 in acetalization of cyclohexanone and meso-TS-1 in hydroxylation of phenol was also studied. The synthesis method reported in this paper is cost-effective and environmental friendly, can be easily expended to prepare other hierarchical structured zeolites. - Graphical abstract: Mesoporous zeolite single crystals were synthesized by using cheap porogens as template. Highlights: > Mesoporous zeolite (silicalite-1, ZSM-5, TS-1) single crystals were synthesized. > Soluble starch or sodium carboxymethyl cellulose (CMC) was used as porogens. > The mesoporous zeolites had connected mesopores although closed pores existed. > Higher catalytic activities were obtained.

  1. Coffee Beans and Rice Paddies - War on the Cheap: American Advisors in El Salvador and Vietnam

    DTIC Science & Technology

    2014-05-19

    COFFEE BEANS AND RICE PADDIES—WAR ON THE CHEAP: AMERICAN ADVISORS IN EL SALVADOR AND VIETNAM A Monograph by LTC Jeremy L. Peifer United...CONTRACT NUMBER Coffee Beans and Rice Paddies – War on the Cheap: American Advisors in El Salvador and Vietnam 5b. GRANT NUMBER 5c. PROGRAM...Prescribed by ANSI Std. Z39.18 MONOGRAPH APPROVAL PAGE Name of Candidate: Lieutenant Colonel Jeremy L. Peifer Monograph Title: Coffee Beans and Rice

  2. A cheap simple ammeter for batteries-and-bulbs activities

    NASA Astrophysics Data System (ADS)

    Kagan, David T.

    2000-04-01

    The use of batteries and bulbs to teach the fundamentals of circuit analysis has been with us for many years. Even recent innovations in pedagogy seem to rely on batteries and bulbs. In addition, the California Science Content Standards for fourth grade require that "students know how to design and build simple series and parallel circuits using components such as wires, batteries, and bulbs." These standards go on to indicate that students should be able to use a compass to detect magnetic fields and know that electric currents produce magnetic fields.

  3. Forced assembly of water-dispersible carbon nanotubes trapped in paper for cheap gas sensors.

    PubMed

    Wang, Jian; Zhang, Xinyue; Huang, Xiaopeng; Wang, Shujun; Qian, Qiuping; Du, Wenbin; Wang, Yapei

    2013-11-25

    A versatile and readily scalable approach to fabricate a cheap and sensitive paper gas sensor is described. Chemically acidified single-walled carbon nanotubes are assembled in paper, forming continuous sensing arrays with a low detection limit and high detection selectivity for ammonia gas.

  4. My School Makes Me Sick: Cheap Solutions to Environmental Problems in Schools.

    ERIC Educational Resources Information Center

    Wiley, Robert

    This paper presents 19 solutions to problems within the school environment: (1) ventilation (e.g., keep the thermostat fan on whenever the room is occupied); (2) filters (e.g., get rid of 20 percent cheap filters); (3) clean the ductwork; (4) avoid car and bus fumes by keeping vehicles 50 feet from the building; (5) sewer vents (vents must…

  5. Cheap Heat.

    ERIC Educational Resources Information Center

    Switzer, Terry G.

    1986-01-01

    Describes an activity from the ninth-grade physical science program at the Energy Management Center, the outdoor science and energy education center for students in Pasco County, Florida. The activity focuses on making an effective solar collector. (JN)

  6. Magnetic Susceptibility of Ancient and Modern Potsherds Using a Fast, Cheap and Portable Probe

    NASA Astrophysics Data System (ADS)

    Glover, P. W.

    2009-05-01

    It has been estimated that there exist over 100 million ancient potsherds in various collections worldwide, many of which have never been studied and for which the provenance is ambiguous or unknown. Indeed, many collections are extremely badly catalogued or completely mixed-up. We have been using a novel portable probe to measure the magnetic susceptibility and electrical conductivity of potsherds in the hope that this fast, cheap and portable measurement can provide data that will help to sort similar looking potsherds into sets in a manner which may help to define their provenance. The probe, which resembles a firearm, uses the Hall effect to make a non-destructive measurement on the potsherd. The probe is attached to an Dell Axim X51 PDA, which runs software that allows the measurement to be carried out and logged. Each measurement, which is made by pressing a button on the gun, takes only a few seconds. We have made measurements on three suites of ancient potsherds as well as a suite of modern potsherds that were created by using a garden centre and a hammer! In each case a set of 5 stacked measurements were taken on the inside and outside faces of the potsherd in two perpendicular directions. Potsherds which were either (i) so flat that the inside and outside could not be distinguished, (ii) so curved (radius of curvature less than 5 cm) that the probe tip could not approach the surface sufficiently closely, or (iii) smaller than the probe tip, were excluded from the suite of measurements. Each suite contained over 50 measureable potsherds. All measurements were completed within one day. In this pilot study we found that (1) each suite was represented by a normal distribution of magnetic susceptibility values, (2) the four different suites could be distinguished statistically on the basis of their magnetic susceptibility measurements, but (3) the distinction was not sufficiently powerful to separate all potsherds (i.e., there was a significant overlap of the

  7. Magnetic susceptibility measurements on ancient and modern potsherds using a fast, cheap and portable probe

    NASA Astrophysics Data System (ADS)

    Glover, P. W. J.

    2009-04-01

    It has been estimated that there exist over 100 million ancient potsherds in various collections worldwide, many of which have never been studied and for which the provenance is ambiguous or unknown. Indeed, many collections are extremely badly catalogued or completely mixed-up. We have been using a novel portable probe to measure the magnetic susceptibility and electrical conductivity of potsherds in the hope that this fast, cheap and portable measurement can provide data that will help to sort similar looking potsherds into sets in a manner which may help to define their provenance. The probe, which resembles a firearm, uses the Hall effect to make a non-destructive measurement on the potsherd. The probe is attached to an Dell Axim X51 PDA, which runs software that allows the measurement to be carried out and logged. Each measurement, which is made by pressing a button on the gun, takes only a few seconds. We have made measurements on three suites of ancient potsherds as well as a suite of modern potsherds that were created by using a garden centre and a hammer! In each case a set of 5 stacked measurements were taken on the inside and outside faces of the potsherd in two perpendicular directions. Potsherds which were either (i) so flat that the inside and outside could not be distinguished, (ii) so curved (radius of curvature less than 5 cm) that the probe tip could not approach the surface sufficiently closely, or (iii) smaller than the probe tip, were excluded from the suite of measurements. Each suite contained over 50 measureable potsherds. All measurements were completed within one day. In this pilot study we found that (1) each suite was represented by a normal distribution of magnestic susceptibility values, (2) the four different suites could be distinguished statistically on the basis of their magnetic susceptibilty measurements, but (3) the distinction was not sufficiently powerful to separate all potsherds (i.e., there was a significant overlap of the

  8. Smoking patterns in Great Britain: the rise of cheap cigarette brands and roll your own (RYO) tobacco

    PubMed Central

    Gilmore, Anna B.; Tavakoly, Behrooz; Hiscock, Rosemary; Taylor, Gordon

    2015-01-01

    Background In Britain, the tobacco industry segments cigarettes into four price categories—premium, mid-price, economy and ultra-low-price (ULP). Our previous work shows that tobacco companies have kept ULP prices stable in real terms. Roll your own (RYO) tobacco remains cheaper still. Methods Analysis of 2001–08 General Household Survey data to examine trends in use of these cheap products and, using logistic regression, the profile of users of these products. Results Among smokers, the proportion using cheap products (economy, ULP and RYO combined) increased significantly in almost all age groups and geographic areas. Increases were most marked in under 24 year olds, 76% of whom smoked cheap cigarettes by 2008. All cheap products were more commonly used in lower socio-economic groups. Men and younger smokers were more likely to smoke RYO while women smoked economy brands. Smokers outside London and the South East of England were more likely to smoke some form of cheap tobacco even once socio-economic differences were accounted for. Conclusions This paper demonstrates that cheap tobacco use is increasing among young and disadvantaged smokers compromising declines in population smoking prevalence. Thus, tobacco industry pricing appears to play a key role in explaining smoking patterns and inequalities in smoking. PMID:25118219

  9. A Rapid and Cheap Methodology for CRISPR/Cas9 Zebrafish Mutant Screening.

    PubMed

    D'Agostino, Ylenia; Locascio, Annamaria; Ristoratore, Filomena; Sordino, Paolo; Spagnuolo, Antonietta; Borra, Marco; D'Aniello, Salvatore

    2016-01-01

    The introduction of new genome editing tools such as ZFNs, TALENs and, more recently, the CRISPR/Cas9 system, has greatly expanded the ability to knock-out genes in different animal models, including zebrafish. However, time and costs required for the screening of a huge number of animals, aimed to identify first founder fishes (F0), and then carriers (F1) are still a bottleneck. Currently, high-resolution melting (HRM) analysis is the most efficient technology for large-scale InDels detection, but the very expensive equipment demanded for its application may represent a limitation for research laboratories. Here, we propose a rapid and cheap method for high-throughput genotyping that displays efficiency rate similar to the HRM. In fact, using a common ViiA™7 real-time PCR system and optimizing the parameters of the melting analysis, we demonstrated that it is possible to discriminate between the mutant and the wild type melting curves. Due to its simplicity, rapidity and cheapness, our method can be used as a preliminary one-step approach for massive screening, in order to restrict the scope at a limited number of embryos and to focus merely on them for the next sequencing step, necessary for the exact sequence identification of the induced mutation. Moreover, thanks to its versatility, this simple approach can be readily adapted to the detection of any kind of genome editing approach directed to genes or regulatory regions and can be applied to many other animal models.

  10. A Class of High Performance Metal-Free Oxygen Reduction Electrocatalysts based on Cheap Carbon Blacks

    PubMed Central

    Sun, Xiujuan; Song, Ping; Zhang, Yuwei; Liu, Changpeng; Xu, Weilin; Xing, Wei

    2013-01-01

    For the goal of practical industrial development of fuel cells, cheap, sustainable and high performance electrocatalysts for oxygen reduction reactions (ORR) which rival those based on platinum (Pt) and other rare materials are highly desirable. In this work, we report a class of cheap and high-performance metal-free oxygen reduction electrocatalysts obtained by co-doping carbon blacks with nitrogen and fluorine (CB-NF).The CB-NF electrocatalysts are highly active and exhibit long-term operation stability and tolerance to poisons during oxygen reduction process in alkaline medium. The alkaline direct methanol fuel cell with the best CB-NF as cathode (3 mg/cm2) outperforms the one with commercial platinum-based cathode (3 mg Pt/cm2). To the best of our knowledge, these are among the most efficient non-Pt based electrocatalysts. Since carbon blacks are 10,000 times cheaper than Pt, these CB-NF electrocatalysts possess the best price/performance ratio for ORR, and are the most promising alternatives to Pt-based ones to date. PMID:23974295

  11. Bunsen's Batteries and the Electric Arc.

    ERIC Educational Resources Information Center

    Stock, John T.

    1995-01-01

    Traces the history of the observation of the production of electric sparks and the early history of battery design. Detail is provided about laboratory experiments performed by Robert Bunsen, who spent a great deal of time developing an efficient and comparatively cheap battery. (36 references) (DDR)

  12. Achieving cheap clean energy for all in the 21^st Century?

    NASA Astrophysics Data System (ADS)

    Gupta, Rajan

    2006-11-01

    Energy is essential for modern life and is a critical resource that we take for granted. Unfortunately, we are increasingly confronted by many unsettling questions: Is there enough cheap oil and gas remaining and should we start changing our life styles towards energy efficiency? What will be the price of oil and gas next year and will we face shortages? Are rising prices reflective of greed and manipulation or geopolitics or of real constraints? Will renewable sources provide a significant fraction of our energy needs? Is global warming already happening and is it a result of our ``addiction to oil''? If the answer to these is ``yes'', then what can we, as individuals, do to help ourselves, the nation, and the world? This talk will attempt to answer these questions by examining the global oil, gas and other resources, emerging constraints and opportunities, and geopolitics.

  13. Power augmentation of cheap, sail-type, horizontal-axis wind-turbines

    NASA Astrophysics Data System (ADS)

    Fleming, P. D.; Probert, S. D.

    1982-09-01

    A history of the development of windpowered machinery is presented, and the installation of tipvanes and centerbodies to enhance the performance of low cost WECS for developing countries are examined experimentally. Particular attention is given to sail wing rotors equipped with tip fins, peristaltic pumps reparable by semiskilled labor, and various configurations of tip fins and center bodies, which deflect the wind outward from the hub to the sails. Cheap, flat-plate tip fins were found to effective in augmenting rotor performance by as much as 1.6 when facing only downwind. Best results were obtained with one tip vane per sail, with the fins downwind a distance at least equal to the pitch of a wind-filled sail. Further experimentation with stationary deflectors which redirect wind into the buckets of a Savonius rotor or the sails of a horizontal axis WECS are suggested.

  14. Lime Juice and Vinegar Injections as a Cheap and Natural Alternative to Control COTS Outbreaks

    PubMed Central

    Moutardier, Grégoire; Gereva, Sompert; Mills, Suzanne C.; Adjeroud, Mehdi; Beldade, Ricardo; Ham, Jayven; Kaku, Rocky; Dumas, Pascal

    2015-01-01

    Outbreaks of the corallivorous crown-of-thorns seastar Acanthaster planci (COTS) represent one of the greatest disturbances to coral reef ecosystems in the Indo-Pacific, affecting not only coral reefs but also the coastal communities which rely on their resources. While injection approaches are increasingly used in an attempt to control COTS densities, most of them display severe drawbacks including logistical challenges, high residual environmental impacts or low cost-effectiveness. We tested a new alternative control method based upon acidic injections of cheap, 100% natural products. We investigated the lethal doses, intra- and inter-specific disease transmission and immune responses of COTS when injected with fresh lime juice (extracted from local Citrus arantifolia) and white spirit vinegar. High COTS mortality was achieved with small volumes: 10–20 ml per seastar induced death in 89%/97% of injected specimens after an average 34.3 h/29.8 h for lime juice and vinegar respectively. Highest efficiency was reached for both solutions with double shots of (2 × 10 ml) in two different areas on the body: 100% mortality occurred within 12–24 h, which is similar or faster compared with other current injection methods. Multiple immune measures suggested that death was very likely caused by pH stress from the acidic solutions rather than a bacterial infection. Contagion to either conspecifics or a variety of other reef species was not observed, even at COTS densities 15 times higher than the highest naturally reported. 10 to 20 l lime juice/vinegar could kill up to a thousand COTS at a cost of less than 0.05 USD per specimen; no permits or special handling procedures are required. We conclude that injections of lime juice and vinegar offer great advantages when compared to current best practises and constitute a cheap and natural option for all reefs affected by COTS. PMID:26356840

  15. Lime Juice and Vinegar Injections as a Cheap and Natural Alternative to Control COTS Outbreaks.

    PubMed

    Moutardier, Grégoire; Gereva, Sompert; Mills, Suzanne C; Adjeroud, Mehdi; Beldade, Ricardo; Ham, Jayven; Kaku, Rocky; Dumas, Pascal

    2015-01-01

    Outbreaks of the corallivorous crown-of-thorns seastar Acanthaster planci (COTS) represent one of the greatest disturbances to coral reef ecosystems in the Indo-Pacific, affecting not only coral reefs but also the coastal communities which rely on their resources. While injection approaches are increasingly used in an attempt to control COTS densities, most of them display severe drawbacks including logistical challenges, high residual environmental impacts or low cost-effectiveness. We tested a new alternative control method based upon acidic injections of cheap, 100% natural products. We investigated the lethal doses, intra- and inter-specific disease transmission and immune responses of COTS when injected with fresh lime juice (extracted from local Citrus arantifolia) and white spirit vinegar. High COTS mortality was achieved with small volumes: 10-20 ml per seastar induced death in 89%/97% of injected specimens after an average 34.3 h/29.8 h for lime juice and vinegar respectively. Highest efficiency was reached for both solutions with double shots of (2 × 10 ml) in two different areas on the body: 100% mortality occurred within 12-24 h, which is similar or faster compared with other current injection methods. Multiple immune measures suggested that death was very likely caused by pH stress from the acidic solutions rather than a bacterial infection. Contagion to either conspecifics or a variety of other reef species was not observed, even at COTS densities 15 times higher than the highest naturally reported. 10 to 20 l lime juice/vinegar could kill up to a thousand COTS at a cost of less than 0.05 USD per specimen; no permits or special handling procedures are required. We conclude that injections of lime juice and vinegar offer great advantages when compared to current best practises and constitute a cheap and natural option for all reefs affected by COTS.

  16. Abundances in Przybylski's star

    NASA Astrophysics Data System (ADS)

    Cowley, C. R.; Ryabchikova, T.; Kupka, F.; Bord, D. J.; Mathys, G.; Bidelman, W. P.

    2000-09-01

    We have derived abundances for 54 elements in the extreme roAp star HD101065. ESO spectra with a resolution of about 80000, and S/N of 200 or more were employed. The adopted model has Teff=6600K, and log(g)=4.2. Because of the increased line opacity and consequent low gas pressure, convection plays no significant role in the temperature structure. Lighter elemental abundances through the iron group scatter about standard abundance distribution (SAD) (solar) values. Iron and nickel are about one order of magnitude deficient while cobalt is enhanced by 1.5dex. Heavier elements, including the lanthanides, generally follow the solar pattern but enhanced by 3 to 4dex. Odd-Z elements are generally less abundant than their even-Z neighbours. With a few exceptions (e.g. Yb), the abundance pattern among the heavy elements is remarkably coherent, and resembles a displaced solar distribution.

  17. OXYGEN ABUNDANCES IN CEPHEIDS

    SciTech Connect

    Luck, R. E.; Andrievsky, S. M.; Korotin, S. N.; Kovtyukh, V. V. E-mail: serkor@skyline.od.ua E-mail: scan@deneb1.odessa.ua

    2013-07-01

    Oxygen abundances in later-type stars, and intermediate-mass stars in particular, are usually determined from the [O I] line at 630.0 nm, and to a lesser extent, from the O I triplet at 615.7 nm. The near-IR triplets at 777.4 nm and 844.6 nm are strong in these stars and generally do not suffer from severe blending with other species. However, these latter two triplets suffer from strong non-local thermodynamic equilibrium (NLTE) effects and thus see limited use in abundance analyses. In this paper, we derive oxygen abundances in a large sample of Cepheids using the near-IR triplets from an NLTE analysis, and compare those abundances to values derived from a local thermodynamic equilibrium (LTE) analysis of the [O I] 630.0 nm line and the O I 615.7 nm triplet as well as LTE abundances for the 777.4 nm triplet. All of these lines suffer from line strength problems making them sensitive to either measurement complications (weak lines) or to line saturation difficulties (strong lines). Upon this realization, the LTE results for the [O I] lines and the O I 615.7 nm triplet are in adequate agreement with the abundance from the NLTE analysis of the near-IR triplets.

  18. Genome Sequence of Lactobacillus rhamnosus Strain CASL, an Efficient l-Lactic Acid Producer from Cheap Substrate Cassava

    PubMed Central

    Yu, Bo; Su, Fei; Wang, Limin; Zhao, Bo; Qin, Jiayang; Ma, Cuiqing; Xu, Ping; Ma, Yanhe

    2011-01-01

    Lactobacillus rhamnosus is a type of probiotic bacteria with industrial potential for l-lactic acid production. We announce the draft genome sequence of L. rhamnosus CASL (2,855,156 bp with a G+C content of 46.6%), which is an efficient producer of l-lactic acid from cheap, nonfood substrate cassava with a high production titer. PMID:22123765

  19. "Cheap, Efficient, and Easy to Implement"? Economic Aspects of Monitorial Education in Swedish Elementary Schools during the 1820s

    ERIC Educational Resources Information Center

    Larsson, Esbjörn

    2016-01-01

    This article investigates the economic aspects of monitorial education in Sweden during the 1820s. In contrast to previous research, which has often emphasised monitorial education as a cheap method of education, this article shows that this was rarely the case. Monitorial education could in fact lead to increased costs, especially during the…

  20. Good, Fast, Cheap: How Centers of Teaching and Learning Can Capitalize in Today's Resource-Constrained Context

    ERIC Educational Resources Information Center

    Truong, Michael H.; Juillerat, Stephanie; Gin, Deborah H. C.

    2016-01-01

    This article provides leaders and educational developers of Centers for Teaching and Learning (CTL) with innovative and practical strategies on how to increase their centers' capacity and impact by focusing on quality, efficiency, and cost. This "good, fast, cheap" model represents a promising way that CTL can continue to grow, scale,…

  1. Field Instrumentation With Bricks: Wireless Networks Built From Tough, Cheap, Reliable Field Computers

    NASA Astrophysics Data System (ADS)

    Fatland, D. R.; Anandakrishnan, S.; Heavner, M.

    2004-12-01

    We describe tough, cheap, reliable field computers configured as wireless networks for distributed high-volume data acquisition and low-cost data recovery. Running under the GNU/Linux open source model these network nodes ('Bricks') are intended for either autonomous or managed deployment for many months in harsh Arctic conditions. We present here results from Generation-1 Bricks used in 2004 for glacier seismology research in Alaska and Antarctica and describe future generation Bricks in terms of core capabilities and a growing list of field applications. Subsequent generations of Bricks will feature low-power embedded architecture, large data storage capacity (GB), long range telemetry (15 km+ up from 3 km currently), and robust operational software. The list of Brick applications is growing to include Geodetic GPS, Bioacoustics (bats to whales), volcano seismicity, tracking marine fauna, ice sounding via distributed microwave receivers and more. This NASA-supported STTR project capitalizes on advancing computer/wireless technology to get scientists more data per research budget dollar, solving system integration problems and thereby getting researchers out of the hardware lab and into the field. One exemplary scenario: An investigator can install a Brick network in a remote polar environment to collect data for several months and then fly over the site to recover the data via wireless telemetry. In the past year Brick networks have moved beyond proof-of-concept to the full-bore development and testing stage; they will be a mature and powerful tool available for IPY 2007-8.

  2. How cheap is soaring flight in raptors? A preliminary investigation in freely-flying vultures.

    PubMed

    Duriez, Olivier; Kato, Akiko; Tromp, Clara; Dell'Omo, Giacomo; Vyssotski, Alexei L; Sarrazin, François; Ropert-Coudert, Yan

    2014-01-01

    Measuring the costs of soaring, gliding and flapping flight in raptors is challenging, but essential for understanding their ecology. Among raptors, vultures are scavengers that have evolved highly efficient soaring-gliding flight techniques to minimize energy costs to find unpredictable food resources. Using electrocardiogram, GPS and accelerometer bio-loggers, we report the heart rate (HR) of captive griffon vultures (Gyps fulvus and G. himalayensis) trained for freely-flying. HR increased three-fold at take-off (characterized by prolonged flapping flight) and landing (>300 beats-per-minute, (bpm)) compared to baseline levels (80-100 bpm). However, within 10 minutes after the initial flapping phase, HR in soaring/gliding flight dropped to values similar to baseline levels, i.e. slightly lower than theoretically expected. However, the extremely rapid decrease in HR was unexpected, when compared with other marine gliders, such as albatrosses. Weather conditions influenced flight performance and HR was noticeably higher during cloudy compared to sunny conditions when prolonged soaring flight is made easier by thermal ascending air currents. Soaring as a cheap locomotory mode is a crucial adaptation for vultures who spend so long on the wing for wide-ranging movements to find food.

  3. Neonatal newborn hearing screening: four years' experience at Ferrara University Hospital (CHEAP project): part 1.

    PubMed

    Ciorba, A; Hatzopoulos, S; Camurri, L; Negossi, L; Rossi, M; Cosso, D; Petruccelli, J; Martini, A

    2007-02-01

    The Child Hearing Early Assessment Programme (CHEAP) regional project, was a combined departmental approach (Audiology, Neonatology) of the University Hospital of Ferrara, aimed at identifying neonatal hearing impairment and defining early intervention strategies. Aims of this project have been: (i) construction of a neonatal screening programme using evoked otoacoustic emission and auditory brainstem responses; (ii) the calculation of a precise estimate of cost-benefits for every child tested; (iii) the development of an information flow instrument (database) for the storage of data and the statistical analysis of the results. The present report refers only to the results of the project related to the otoacoustic emission data from well-babies and intensive care unit residents. In the period January 2000-December 2004, 4269 full-term newborns and 654 Neonatal Intensive Care Unit babies were tested at the Neonatology Department. The cost of the Universal Neonatal Hearing Screening was estimated at Euro 9.20 per child, considering the use of the ILO-292 apparatus, and Euro 8.28 per child in the case of an automatic screener. In this screening model, the initial hardware costs can be re-iterated into budget in a period of two years, if 1000 children per year are tested.

  4. How Cheap Is Soaring Flight in Raptors? A Preliminary Investigation in Freely-Flying Vultures

    PubMed Central

    Duriez, Olivier; Kato, Akiko; Tromp, Clara; Dell'Omo, Giacomo; Vyssotski, Alexei L.; Sarrazin, François; Ropert-Coudert, Yan

    2014-01-01

    Measuring the costs of soaring, gliding and flapping flight in raptors is challenging, but essential for understanding their ecology. Among raptors, vultures are scavengers that have evolved highly efficient soaring-gliding flight techniques to minimize energy costs to find unpredictable food resources. Using electrocardiogram, GPS and accelerometer bio-loggers, we report the heart rate (HR) of captive griffon vultures (Gyps fulvus and G. himalayensis) trained for freely-flying. HR increased three-fold at take-off (characterized by prolonged flapping flight) and landing (>300 beats-per-minute, (bpm)) compared to baseline levels (80–100 bpm). However, within 10 minutes after the initial flapping phase, HR in soaring/gliding flight dropped to values similar to baseline levels, i.e. slightly lower than theoretically expected. However, the extremely rapid decrease in HR was unexpected, when compared with other marine gliders, such as albatrosses. Weather conditions influenced flight performance and HR was noticeably higher during cloudy compared to sunny conditions when prolonged soaring flight is made easier by thermal ascending air currents. Soaring as a cheap locomotory mode is a crucial adaptation for vultures who spend so long on the wing for wide-ranging movements to find food. PMID:24454760

  5. Predictable and predictive emotions: explaining cheap signals and trust re-extension

    PubMed Central

    Schniter, Eric; Sheremeta, Roman M.

    2014-01-01

    Despite normative predictions from economics and biology, unrelated strangers will often develop the trust necessary to reap gains from one-shot economic exchange opportunities. This appears to be especially true when declared intentions and emotions can be cheaply communicated. Perhaps even more puzzling to economists and biologists is the observation that anonymous and unrelated individuals, known to have breached trust, often make effective use of cheap signals, such as promises and apologies, to encourage trust re-extension. We used a pair of trust games with one-way communication and an emotion survey to investigate the role of emotions in regulating the propensity to message, apologize, re-extend trust, and demonstrate trustworthiness. This design allowed us to observe the endogenous emergence and natural distribution of trust-relevant behaviors, remedial strategies used by promise-breakers, their effects on behavior, and subsequent outcomes. We found that emotions triggered by interaction outcomes are predictable and also predict subsequent apology and trust re-extension. The role of emotions in behavioral regulation helps explain why messages are produced, when they can be trusted, and when trust will be re-extended. PMID:25477797

  6. Na+/K+-ATPase α-subunit (nkaα) Isoforms and Their mRNA Expression Levels, Overall Nkaα Protein Abundance, and Kinetic Properties of Nka in the Skeletal Muscle and Three Electric Organs of the Electric Eel, Electrophorus electricus

    PubMed Central

    Hiong, Kum C.; Boo, Mel V.; Choo, Celine Y. L.; Wong, Wai P.; Chew, Shit F.; Ip, Yuen K.

    2015-01-01

    This study aimed to obtain the coding cDNA sequences of Na+/K+-ATPase α (nkaα) isoforms from, and to quantify their mRNA expression in, the skeletal muscle (SM), the main electric organ (EO), the Hunter’s EO and the Sach’s EO of the electric eel, Electrophorus electricus. Four nkaα isoforms (nkaα1c1, nkaα1c2, nkaα2 and nkaα3) were obtained from the SM and the EOs of E. electricus. Based on mRNA expression levels, the major nkaα expressed in the SM and the three EOs of juvenile and adult E. electricus were nkaα1c1 and nkaα2, respectively. Molecular characterization of the deduced Nkaα1c1 and Nkaα2 sequences indicates that they probably have different affinities to Na+ and K+. Western blotting demonstrated that the protein abundance of Nkaα was barely detectable in the SM, but strongly detected in the main and Hunter’s EOs and weakly in the Sach’s EO of juvenile and adult E. electricus. These results corroborate the fact that the main EO and Hunter’s EO have high densities of Na+ channels and produce high voltage discharges while the Sach’s EO produces low voltage discharges. More importantly, there were significant differences in kinetic properties of Nka among the three EOs of juvenile E. electricus. The highest and lowest Vmax of Nka were detected in the main EO and the Sach’s EO, respectively, with the Hunter’s EO having a Vmax value intermediate between the two, indicating that the metabolic costs of EO discharge could be the highest in the main EO. Furthermore, the Nka from the main EO had the lowest Km (or highest affinity) for Na+ and K+ among the three EOs, suggesting that the Nka of the main EO was more effective than those of the other two EOs in maintaining intracellular Na+ and K+ homeostasis and in clearing extracellular K+ after EO discharge. PMID:25793901

  7. Bioinformatics: Cheap and robust method to explore biomaterial from Indonesia biodiversity

    NASA Astrophysics Data System (ADS)

    Widodo

    2015-02-01

    Indonesia has a huge amount of biodiversity, which may contain many biomaterials for pharmaceutical application. These resources potency should be explored to discover new drugs for human wealth. However, the bioactive screening using conventional methods is very expensive and time-consuming. Therefore, we developed a methodology for screening the potential of natural resources based on bioinformatics. The method is developed based on the fact that organisms in the same taxon will have similar genes, metabolism and secondary metabolites product. Then we employ bioinformatics to explore the potency of biomaterial from Indonesia biodiversity by comparing species with the well-known taxon containing the active compound through published paper or chemical database. Then we analyze drug-likeness, bioactivity and the target proteins of the active compound based on their molecular structure. The target protein was examined their interaction with other proteins in the cell to determine action mechanism of the active compounds in the cellular level, as well as to predict its side effects and toxicity. By using this method, we succeeded to screen anti-cancer, immunomodulators and anti-inflammation from Indonesia biodiversity. For example, we found anticancer from marine invertebrate by employing the method. The anti-cancer was explore based on the isolated compounds of marine invertebrate from published article and database, and then identified the protein target, followed by molecular pathway analysis. The data suggested that the active compound of the invertebrate able to kill cancer cell. Further, we collect and extract the active compound from the invertebrate, and then examined the activity on cancer cell (MCF7). The MTT result showed that the methanol extract of marine invertebrate was highly potent in killing MCF7 cells. Therefore, we concluded that bioinformatics is cheap and robust way to explore bioactive from Indonesia biodiversity for source of drug and another

  8. Application of statistical experimental design for optimisation of bioinsecticides production by sporeless Bacillus thuringiensis strain on cheap medium.

    PubMed

    Ben Khedher, Saoussen; Jaoua, Samir; Zouari, Nabil

    2013-01-01

    In order to overproduce bioinsecticides production by a sporeless Bacillus thuringiensis strain, an optimal composition of a cheap medium was defined using a response surface methodology. In a first step, a Plackett-Burman design used to evaluate the effects of eight medium components on delta-endotoxin production showed that starch, soya bean and sodium chloride exhibited significant effects on bioinsecticides production. In a second step, these parameters were selected for further optimisation by central composite design. The obtained results revealed that the optimum culture medium for delta-endotoxin production consists of 30 g L(-1) starch, 30 g L(-1) soya bean and 9 g L(-1) sodium chloride. When compared to the basal production medium, an improvement in delta-endotoxin production up to 50% was noted. Moreover, relative toxin yield of sporeless Bacillus thuringiensis S22 was improved markedly by using optimised cheap medium (148.5 mg delta-endotoxins per g starch) when compared to the yield obtained in the basal medium (94.46 mg delta-endotoxins per g starch). Therefore, the use of optimised culture cheap medium appeared to be a good alternative for a low cost production of sporeless Bacillus thuringiensis bioinsecticides at industrial scale which is of great importance in practical point of view.

  9. Ammonia abundances in comets

    NASA Astrophysics Data System (ADS)

    Wyckoff, S.; Tegler, S.; Engel, L.

    The emission band strengths of the NH2 bands of Comets Halley, Hartley-Good, Thiele, and Borrelly were measured to determine the NH2 column densities for the comets. Production rates obtained using the Haser and vectorial models are in agreement within the observational errors, suggesting that a simple two-step decay model may be used to approximate the NH2 distribution in a comet's coma. Ammonia-to-water abundance ratios from 0.01 to 0.4 percent were found for the four comets. The ratio in Comet Halley is found to be Q(NH3)/Q(H2O) = 0.002 + or - 0.001. No significant difference in the ammonia abundance was found before or after perihelion in Comet Halley.

  10. Cheap and Cheerful Stream Restoration - An Example of System Wide Woody Addition Treatment

    NASA Astrophysics Data System (ADS)

    Wheaton, J. M.; Bennett, S. N.; Bouwes, N.; Camp, R.

    2012-12-01

    Stream restoration has been plagued with high price tags, limited spatial extents, and questionable effectiveness in light of largely absent monitoring efforts. One prominent example is the placement of large woody debris (LWD) structures and engineered log jams that are frequently employed to promote heterogeneity of instream habitat. Ironically, many of these treatments attempt to lock in place and over-engineer the woody structures as opposed to allowing them to adjust and rearrange themselves as natural LWD would have. We are in the midst of a large scale restoration experiment using LWD to recover ESA-listed steelhead trout (Oncorhynchus mykiss) populations in the Asotin Creek Watershed of Southeast Washington. The project is an Intensively Monitored Watershed (IMW) where the restoration treatment and monitoring use a hierarchal staircase design maximizing the power to detect a population level response in steelhead. We are treating over 12 km of stream with enough LWD input (> 200 pieces per km) to mimic the historic background wood loading and encourage the stream to reshape and regularly rework itself leaving. We are using hundreds of structures we call DWS (dynamic woody structures), which generally consist of a series of wooden fence posts driven into the stream bed and complex LWD anchored between them to invoke a specific hydrogeomorphic response. The real advantage of these DWS are their cost. They can be installed quickly (15-30 minutes each) and cheaply (< $100/DWS); even in remote settings with a 2-3 person crew, hydraulic post pounder, very cheap materials, and avoiding impacts associated with operating heavy equipment. This allows us to install lots of the structures at high density (every 5-15 channel widths) over an entire stream system. We call this overall approach System Wide Woody Addition Treatment (SWWAT). In the long term, we hypothesize that the SWWAT will provide an intial input LWD that will become a part of study creeks which are more

  11. Flare Plasma Iron Abundance

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.; Dan, Chau; Jain, Rajmal; Schwartz, Richard A.; Tolbert, Anne K.

    2008-01-01

    The equivalent width of the iron-line complex at 6.7 keV seen in flare X-ray spectra suggests that the iron abundance of the hottest plasma at temperatures >approx.10 MK may sometimes be significantly lower than the nominal coronal abundance of four times the photospheric value that is commonly assumed. This conclusion is based on X-ray spectral observations of several flares seen in common with the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and the Solar X-ray Spectrometer (SOXS) on the second Indian geostationary satellite, GSAT-2. The implications of this will be discussed as it relates to the origin of the hot flare plasma - either plasma already in the corona that is directly heated during the flare energy release process or chromospheric plasma that is heated by flare-accelerated particles and driven up into the corona. Other possible explanations of lower-than-expected equivalent widths of the iron-line complex will also be discussed.

  12. Oxygen abundance and convection

    NASA Astrophysics Data System (ADS)

    Van't Veer, C.; Cayrel, R.

    The triplet IR lines of O I near 777 nm are computed with the Kurucz's code, modified to accept several convection models. The program has been run with the MLT algorithm, with l/H = 1.25 and 0.5, and with the Canuto-Mazzitelli and Canuto-Goldman-Mazzitelli approaches, on a metal-poor turnoff-star model atmosphere with Teff=6200 K, log g = 4.3, [Fe/H]= -1.5. The results show that the differences in equivalent widths for the 4 cases do not exceed 2 per cent (0.3 mA). The convection treatment is therefore not an issue for the oxygen abundance derived from the permitted lines.

  13. Capella: Structure and Abundances

    NASA Technical Reports Server (NTRS)

    Brickhouse, Nancy S.

    1999-01-01

    This grant covers the analysis of EUVE spectra of the cool star binary system Capella. This project has also required the analysis of simultaneous Advanced Satellite for Cosmology and Astrophysics (ASCA) data. The ASCA spectrum of Capella could not be fit with standard models; by imposing models based on strong lines observed with EUVE, a problem wavelength region was identified. Correcting the problem required calculations of atomic collision strengths of higher principal quantum number than had ever been calculated. With these new models applied to the ASCA spectrum, better fits were obtained. Findings are that: (1) ASCA and EUVE spectra are both dominated by a region at 6 x 10(exp 6) K. (2) The high energy cut-off of the ASCA spectrum is consistent with emission from the highest ionization stages of EUVE, namely Fe XXIV. (3) EUVE requires a continuous emission measure distribution with more than two temperatures. (4) The ASCA spectra are of such high statistical significance that systematic uncertainties dominate, including atomic physics issues and calibration issues. (5) While the ASCA spectral fits achieve lower Chi(exp 2 with two-temperature fits, the EUVE-derived emission measure distribution models are also consistent with the spectra. (6) The Fe/H ratio obtained from the ASCA fit is within 20 % of the Fe/H abundance obtained from the summed spectra of Capella over 5 EUVE pointings, as well as the 1996 EUVE data. This result confirms our claims that quasi-continua composed of weak emission lines in the short wavelength spectrometer of EUVE are not major contributors to the measured Capella continuum. Other abundance ratios are also determined from the ASCA data, using models derived with EUVE. Si, Si, and Mg appear to be close to solar photospheric values, while the ratio of Ne/Fe is three to four times lower than solar photospheric values. Whether there is a general First Ionization Potential (FIP) effect or a specific neon anomaly cannot be determined

  14. Actinide abundances in ordinary chondrites

    NASA Technical Reports Server (NTRS)

    Hagee, B.; Bernatowicz, T. J.; Podosek, F. A.; Johnson, M. L.; Burnett, D. S.

    1990-01-01

    Measurements of actinide and light REE (LREE) abundances and of phosphate abundances in equilibrated ordinary chondrites were obtained and were used to define the Pu abundance in the solar system and to determine the degree of variation of actinide and LREE abundances. The results were also used to compare directly the Pu/U ratio with the earlier obtained ratio determined indirectly, as (Pu/Nd)x(Nd/U), assuming that Pu behaves chemically as a LREE. The data, combined with high-accuracy isotope-dilution data from the literature, show that the degree of gram-scale variability of the Th, U, and LREE abundances for equilibrated ordinary chondrites is a factor of 2-3 for absolute abundances and up to 50 percent for relative abundances. The observed variations are interpreted as reflecting the differences in the compositions and/or proportions of solar nebula components accreted to ordinary chondrite parent bodies.

  15. The end of suburbia: what happens when all the cheap oil is gone and what are the health implications?

    PubMed

    Parker, Alan A

    2005-04-01

    In isolation, the depletion of the world's stocks of cheap oil is a risk management problem of global proportions. The risk would be manageable given an international agreement by all the developed nations to conserve much of the remaining cheap oil for essential purposes, but there is no such agreement nor is there any intent to create one. Evidence is presented to show that the synergetic interaction of oil depletion with other long-standing environmental problems will result in world food production peaking and then declining at a rapid rate. Australian Census data for the journey to work and the growth of car ownership are analysed. It reveals that car/ oil dependency is growing in outer suburbia, where most Australians live and where future population growth will be housed. It is argued that oil dependency, if not reduced, will develop into a serious threat to national security in a few years. Health promotion professionals have an important role in activating local, State and Commonwealth governments to implement 'travel smart' programs.

  16. Three Inexpensive Static-Electricity Demonstrations.

    ERIC Educational Resources Information Center

    Gore, Gordon R.; Gregg, William R.

    1992-01-01

    Describes demonstrations to (1) construct an inexpensive static electricity detector; (2) obtain an abundant supply of either negative or positive charge using household items; and (3) create static electricity using a Tesla coil or Van de Graaff generator. (MDH)

  17. Electric utilities and the info-way - are electrics and telcos fellow travelers or competitors

    SciTech Connect

    Ashworth, M.J.

    1994-03-15

    This article examines the future role of telecommunications and the so-called information superhighway in the operations of electric utilities. Utilities should take advantage of information technology through informal alliances with telecommunications hardware and service suppliers, should limit investments in alternative meter-level technologies to those that are cheap, easily integrated, and flexible, and should consider outsourcing network implementation, maintenance, and management functions.

  18. Capella: Structure and Abundances

    NASA Technical Reports Server (NTRS)

    Brickhouse, Nancy S.

    1999-01-01

    This grant covers the analysis of ASCA spectra of the cool star binary system Capella. This project has also required the analysis of simultaneous EUVE data. The ASCA spectrum of Capella could not be fit with standard models; by imposing models based on strong lines observed with EUVE, a problem wavelength region was identified. Correcting the problem required calculations of atomic collision strengths of higher principal quantum number than had ever been calculated, resulting in a paper in process by Liedahl and Brickhouse. With these new models applied to the ASCA spectrum, better fits were obtained. While solar abundance ratios are generally consistent with the ASCA data, the ratio of Ne/Fe is three to four times lower than solar photospheric values. Whether there is a general First Ionization Potential (FIP) effect or a specific neon anomaly cannot be determined from these data. Detailed discussion has been provided to NASA in the most recent annual report (1997). Two poster presentations have been made regarding modeling requirements. A substantial paper is in the final revision form, following review by six co-authors. The results of this work have wide implications, since the newly calculated emission lines almost certainly contribute to other problems in fitting not only other stellar spectra, but also composite supernova remnants, galaxies, and cooling flow clusters of galaxies. Furthermore, Liedahl and Brickhouse have identified other species for which lines of a similar nature (high principal quantum number) will contribute significant flux. For moderate resolution X-ray spectra, lines left out of the models in relatively isolated bands, will be attributed to continuum flux by spectral fitting engines, causing errors in line-to-continuum ratios. Thus addressing the general theoretical problem is of crucial importance.

  19. Measuring Solar Abundances with Seismology

    NASA Astrophysics Data System (ADS)

    Mussack, K.; Gough, D.

    2009-12-01

    The revision of the photospheric abundances proferred by Asplund et al. (2005) has rendered opacity theory inconsistent with the seismologically determined opacity through the Sun. This highlights the need for a direct seismological measurement of solar abundances. Here we describe the technique used to measure abundances with seismology, examine our ability to detect differences between solar models using this technique, and discuss its application in the Sun.

  20. Cheap-GSHPs, an European project aiming cost-reducing innovations for shallow geothermal installations. - Geological data reinterpretation

    NASA Astrophysics Data System (ADS)

    Bertermann, David; Müller, Johannes; Galgaro, Antonio; Cultrera, Matteo; Bernardi, Adriana; Di Sipio, Eloisa

    2016-04-01

    The success and widespread diffusion of new sustainable technologies are always strictly related to their affordability. Nowadays the energy price fluctuations and the economic crisis are jeopardizing the development and diffusion of renewable technologies and sources. With the aim of both reduce the overall costs of shallow geothermal systems and improve their installation safety, an European project has took place recently, under the Horizon 2020 EU Framework Programme for Research and Innovation. The acronym of this project is Cheap-GSHPs, meaning "cheap and efficient application of reliable ground source heat exchangers and pumps"; the CHEAP-GSHPs project involves 17 partners among 9 European countries such Belgium, France, Germany, Greece, Ireland, Italy, Romania, Spain, Switzerland. In order to achieve the planned targets, an holistic approach is adopted, where all involved elements that take part of shallow geothermal activities are here integrated. In order to reduce the drilling specific costs and for a solid planning basis the INSPIRE-conformal ESDAC data set PAR-MAT-DOM ("parent material dominant") was analysed and reinterpreted regarding the opportunities for cost reductions. Different ESDAC classification codes were analysed lithologically and sedimentologically in order to receive the most suitable drilling technique within different formations. Together with drilling companies this geological data set was translated into a geotechnical map which allows drilling companies the usage of the most efficient drilling within a certain type of underground. The scale of the created map is 1: 100,000 for all over Europe. This leads to cost reductions for the final consumers. Further there will be the definition of different heat conductivity classes based on the reinterpreted PAR-MAT-DOM data set which will provide underground information. These values will be reached by sampling data all over Europe and literature data. The samples will be measured by several

  1. Cheap glass fiber mats as a matrix of gel polymer electrolytes for lithium ion batteries

    PubMed Central

    Zhu, Yusong; Wang, Faxing; Liu, Lili; Xiao, Shiyin; Yang, Yaqiong; Wu, Yuping

    2013-01-01

    Lithium ion batteries (LIBs) are going to play more important roles in electric vehicles and smart grids. The safety of the current LIBs of large capacity has been remaining a challenge due to the existence of large amounts of organic liquid electrolytes. Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety. However, the application of GPEs is handicapped by their poor mechanical strength and high cost. Here, we report an economic gel-type composite membrane with high safety and good mechanical strength based on glass fiber mats, which are separator for lead-acid batteries. The gelled membrane exhibits high ionic conductivity (1.13 mS cm−1), high Li+ ion transference number (0.56) and wide electrochemical window. Its electrochemical performance is evaluated by LiFePO4 cathode with good cycling. The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost. PMID:24216756

  2. Cheap glass fiber mats as a matrix of gel polymer electrolytes for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Zhu, Yusong; Wang, Faxing; Liu, Lili; Xiao, Shiyin; Yang, Yaqiong; Wu, Yuping

    2013-11-01

    Lithium ion batteries (LIBs) are going to play more important roles in electric vehicles and smart grids. The safety of the current LIBs of large capacity has been remaining a challenge due to the existence of large amounts of organic liquid electrolytes. Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety. However, the application of GPEs is handicapped by their poor mechanical strength and high cost. Here, we report an economic gel-type composite membrane with high safety and good mechanical strength based on glass fiber mats, which are separator for lead-acid batteries. The gelled membrane exhibits high ionic conductivity (1.13 mS cm-1), high Li+ ion transference number (0.56) and wide electrochemical window. Its electrochemical performance is evaluated by LiFePO4 cathode with good cycling. The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost.

  3. Measurement of elastic nonlinearity using remote laser ultrasonics and CHeap Optical Transducers and dual frequency surface acoustic waves.

    PubMed

    Collison, I J; Stratoudaki, T; Clark, M; Somekh, M G

    2008-11-01

    A nonlinear ultrasonic technique for evaluating material elastic nonlinearity has been developed. It measures the phase modulation of a high frequency (82MHz) surface acoustic wave interacting with a low frequency (1MHz) high amplitude stress inducing surface acoustic wave. A new breed of optical transducers has been developed and used for the generation and detection of the high frequency wave. The CHeap Optical Transducer (CHOT) is an ultrasonic transducer system, optically activated and read by a laser. We show that CHOTs offer advantages over alternative transducers. CHOTs and nonlinear ultrasonics have great potential for aerospace applications. Results measuring changes in ultrasonic velocity corresponding to different stress states of the sample are presented on fused silica and aluminium.

  4. Fencing and mowing as effective methods for reducing tick abundance on very small, infested plots.

    PubMed

    Del Fabbro, Simone

    2015-03-01

    The tick Ixodes ricinus (L.) transmits a large variety of pathogens to humans and is therefore a matter of concern for public health. Different strategies for reducing the risk of tick bite, and thus of infection, have been developed and vary according to the kind of exposure (occupational, recreational, peridomestic). The present study (carried out in an endemic region for both Lyme borreliosis and tick-borne encephalitis) aimed to assess the efficacy of two simple and cheap interventions for reducing I. ricinus abundance around residential properties surrounded by wooded areas. The immediate impact of exclosures (host-targeted control methods) and mowing (vegetation management) on very small surfaces (<1ha) were evaluated both alone and in combination. Results suggest that fencing (even if applied on very small surfaces), by preventing the entrance of tick reproductive hosts, can decrease the abundance of parasites in a short time, and that mowing can contribute to reach the goal. This control method could be of great value in small portions of heavily infested areas that have to be kept tick-free to reduce the risk of peridomestic exposure or to permit their recreational use (e.g. picnic areas within natural parks). Benefits appear even greater when considering that these interventions are environmental safe, cheap, technically simple and effective even in close proximity to heavy infested woodlands.

  5. Chemoselective single-site Earth-abundant metal catalysts at metal-organic framework nodes

    NASA Astrophysics Data System (ADS)

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X.; Urban, Ania; Thacker, Nathan C.; Lin, Wenbin

    2016-08-01

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal-organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C-H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

  6. Chemoselective single-site Earth-abundant metal catalysts at metal-organic framework nodes.

    PubMed

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X; Urban, Ania; Thacker, Nathan C; Lin, Wenbin

    2016-08-30

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal-organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C-H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

  7. Chemoselective single-site Earth-abundant metal catalysts at metal–organic framework nodes

    SciTech Connect

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X.; Urban, Ania; Thacker, Nathan C.; Lin, Wenbin

    2016-08-30

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal–organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C–H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals.

  8. The boron abundance of Procyon

    NASA Technical Reports Server (NTRS)

    Lemke, Michael; Lambert, David L.; Edvardsson, Bengt

    1993-01-01

    The B I 2496.8 A resonance line and HST/GHRS echelle spectra are used with model atmospheres and synthetic spectra to derive the B abundance of the F dwarfs Procyon (Alpha Canis Minoris), Theta Ursae Majoris, and Iota Pegasi. The B abundance of Theta UMa and Iota Peg is similar to that derived by Boesgaard and Heacox (1978) from the B II resonance line in spectra of A- and B-type stars. These two dwarfs show normal abundances of Li, Be, and B. Procyon, which is highly depleted in Li and Be, is depleted in B by a factor of at least 3. Comparison of the spectra of Procyon and the halo dwarf HD 140283 shows that the B abundance assigned by Duncan et al. (1992) to three halo dwarfs is not greatly overestimated as a result of contamination of the B I line by an unidentified line.

  9. Ammonia abundances in four comets

    NASA Astrophysics Data System (ADS)

    Wyckoff, S.; Tegler, S. C.; Engel, L.

    1991-02-01

    NH2 emission band strengths were measured in four comets and the NH2 column densities were determined in order to measure the ammonia content of the comets. The mean ammonia/water abundance ratio derived for the four comets is found to be 0.13 + or - 0.06 percent, with no significant variation among the comets. The uniformity of this abundance attests to a remarkable degree of chemical homogeneity over large scales in the comet-forming region of the primordial solar nebula, and contrasts with the CO abundance variations found previously in comets. The N2 and NH3 abundances indicate a condensation temperature in the range 20-160 K, consistent with virtually all comet formation hypotheses.

  10. The boron abundance of Procyon

    NASA Astrophysics Data System (ADS)

    Lemke, Michael; Lambert, David L.; Edvardsson, Bengt

    1993-05-01

    The B I 2496.8 A resonance line and HST/GHRS echelle spectra are used with model atmospheres and synthetic spectra to derive the B abundance of the F dwarfs Procyon (Alpha Canis Minoris), Theta Ursae Majoris, and Iota Pegasi. The B abundance of Theta UMa and Iota Peg is similar to that derived by Boesgaard and Heacox (1978) from the B II resonance line in spectra of A- and B-type stars. These two dwarfs show normal abundances of Li, Be, and B. Procyon, which is highly depleted in Li and Be, is depleted in B by a factor of at least 3. Comparison of the spectra of Procyon and the halo dwarf HD 140283 shows that the B abundance assigned by Duncan et al. (1992) to three halo dwarfs is not greatly overestimated as a result of contamination of the B I line by an unidentified line.

  11. Chlorine Abundances in Cool Stars

    NASA Astrophysics Data System (ADS)

    Maas, Z. G.; Pilachowski, C. A.; Hinkle, K.

    2016-12-01

    Chlorine abundances are reported in 15 evolved giants and 1 M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H35Cl at 3.69851 μm. The high-resolution L-band spectra were observed using the Phoenix infrared spectrometer on the Kitt Peak Mayall 4 m telescope. The average [35Cl/Fe] abundance in stars with -0.72 < [Fe/H] < 0.20 is [35Cl/Fe] = (-0.10 ± 0.15) dex. The mean difference between the [35Cl/Fe] ratios measured in our stars and chemical evolution model values is (0.16 ± 0.15) dex. The [35Cl/Ca] ratio has an offset of ˜0.35 dex above model predictions, suggesting that chemical evolution models are underproducing Cl at the high metallicity range. Abundances of C, N, O, Si, and Ca were also measured in our spectral region and are consistent with F and G dwarfs. The Cl versus O abundances from our sample match Cl abundances measured in planetary nebula and H ii regions. In one star where both H35Cl and H37Cl could be measured, a 35Cl/37Cl isotope ratio of 2.2 ± 0.4 was found, consistent with values found in the Galactic ISM and predicted chemical evolution models.

  12. Solar-powered saline sorbent-solution heat pump/storage system. [Coastal Energy Laboratory-Chemical Heat Pump (CEL-CHEAP)

    SciTech Connect

    Robison, H.; Houston, S.

    1981-01-01

    Coastal Energy Laboratory Chemical Heat Pump (CEL-CHEAP) is a redesigned open-cycle liquid desiccant air conditioner. Heat is discharged to shallow-well water by dehumidification-humidification for cooling and extracted by humidification-dehumidification for heating. Direct solar radiation concentrates the desiccant. For continuous operation, a small uninsulated tank stores concentrated solution. 6 refs.

  13. Nitrites in induced sputum as a simple and cheap non-invasive marker of airway inflammation for asthmatic schoolchildren.

    PubMed

    Recabarren, Arturo; Apaza, Carlos; Castro-Rodríguez, José A

    2008-08-01

    To determine if there are differences in the nitric oxide metabolites (nitrites) in sputum of patients with persistent asthma and healthy schoolchildren, we performed a case-control study in a tertiary care hospital in Arequipa, Perú. Nitrites in induced sputum samples were measured using the Griess assay in 30 persistent asthmatics (mean age of 10.1 yr) and 30 controls (mean age of 11.9 yr). The mean +/- s.d. of nitrites among asthmatics was significantly higher than the controls (16.30 +/- 8.6 vs. 10.25 +/- 4.68 nmol/ml, respectively, p = 0.001). Moreover, the nitrite level in the sputum in children with severe persistent asthma was higher than in the level found in the moderate and mild asthmatics (32.83 +/- 9.48 vs. 18.10 +/- 1.96 vs. 11.84 +/- 4.73 nmol/ml, respectively, p < 0.01 for linear trend). This study showed for the first time in children that asthmatics have significantly higher levels of nitrites in induced sputum than healthy controls and that the level of nitrite correlates with the severity of the asthma. Nitrite levels in sputum, a simple and cheap, non-invasive method, may be a good alternative to measure the severity of inflammation in asthmatic children.

  14. CheapStat: an open-source, "do-it-yourself" potentiostat for analytical and educational applications.

    PubMed

    Rowe, Aaron A; Bonham, Andrew J; White, Ryan J; Zimmer, Michael P; Yadgar, Ramsin J; Hobza, Tony M; Honea, Jim W; Ben-Yaacov, Ilan; Plaxco, Kevin W

    2011-01-01

    Although potentiostats are the foundation of modern electrochemical research, they have seen relatively little application in resource poor settings, such as undergraduate laboratory courses and the developing world. One reason for the low penetration of potentiostats is their cost, as even the least expensive commercially available laboratory potentiostats sell for more than one thousand dollars. An inexpensive electrochemical workstation could thus prove useful in educational labs, and increase access to electrochemistry-based analytical techniques for food, drug and environmental monitoring. With these motivations in mind, we describe here the CheapStat, an inexpensive (<$80), open-source (software and hardware), hand-held potentiostat that can be constructed by anyone who is proficient at assembling circuits. This device supports a number of potential waveforms necessary to perform cyclic, square wave, linear sweep and anodic stripping voltammetry. As we demonstrate, it is suitable for a wide range of applications ranging from food- and drug-quality testing to environmental monitoring, rapid DNA detection, and educational exercises. The device's schematics, parts lists, circuit board layout files, sample experiments, and detailed assembly instructions are available in the supporting information and are released under an open hardware license.

  15. Astrophotography on the Cheap

    ERIC Educational Resources Information Center

    Niederriter, Chuck; Belloni, Mario

    2012-01-01

    Teaching introductory astronomy means discussing celestial objects that are beyond most students' experience. Simply talking about them is usually not sufficient to convey their size, distance, complexity, and beauty. One way that we introduce our students to celestial objects is through observing sessions, but we have also extended these…

  16. No cheap substitutes.

    PubMed

    Griffiths, Peter

    2016-06-15

    The Nuffield Trust report on reshaping the healthcare workforce was published last month. Its conclusions were widely reported as a recommendation to 'train up' nurses as a solution to junior doctor shortages, with support workers, in turn, substituting for registered nurses.

  17. Solar and stellar photospheric abundances

    NASA Astrophysics Data System (ADS)

    Allende Prieto, Carlos

    2016-12-01

    The determination of photospheric abundances in late-type stars from spectroscopic observations is a well-established field, built on solid theoretical foundations. Improving those foundations to refine the accuracy of the inferred abundances has proven challenging, but progress has been made. In parallel, developments on instrumentation, chiefly regarding multi-object spectroscopy, have been spectacular, and a number of projects are collecting large numbers of observations for stars across the Milky Way and nearby galaxies, promising important advances in our understanding of galaxy formation and evolution. After providing a brief description of the basic physics and input data involved in the analysis of stellar spectra, a review is made of the analysis steps, and the available tools to cope with large observational efforts. The paper closes with a quick overview of relevant ongoing and planned spectroscopic surveys, and highlights of recent research on photospheric abundances.

  18. A quick, easy, cheap, effective, rugged and safe extraction method followed by liquid chromatography-(Orbitrap) high resolution mass spectrometry to determine benzotriazole, benzothiazole and benzenesulfonamide derivates in sewage sludge.

    PubMed

    Herrero, Pol; Borrull, Francesc; Pocurull, Eva; Marcé, Rosa M

    2014-04-25

    A Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction method followed by liquid chromatography-(Orbitrap) high resolution mass spectrometry was developed for the simultaneous determination of five benzotriazole, four benzothiazole and five benzenesulfonamide derivates in sewage sludge. While the method was being developed, several buffers and dispersive solid-phase extraction clean-up (dSPE) sorbents were tested. Citrate buffer and Z-sep+ (zirconium-based sorbent) were the most effective extraction buffer and dSPE clean-up material. The absolute recoveries were higher than 80% for all compounds (100ng/g (d.w.)) and the matrix effect was less than -20% for most compounds. The limits of detection were between 0.5 and 10ng/g (d.w.) and the limits of quantification (LOQ) were between 1 and 25ng/g (d.w.). Repeatability and reproducibility were lower than 15% (%RSD, n=5). Several sludge samples from five sewage treatment plants in Catalonia were analysed and the most abundant compounds were 2-hydroxybenzothiazole (

  19. Robust Abundance Estimation in Animal Abundance Surveys with Imperfect Detection

    EPA Science Inventory

    Surveys of animal abundance are central to the conservation and management of living natural resources. However, detection uncertainty complicates the sampling process of many species. One sampling method employed to deal with this problem is depletion (or removal) surveys in whi...

  20. The solar abundance of beryllium

    NASA Technical Reports Server (NTRS)

    Ross, J. E.; Aller, L. H.

    1974-01-01

    The solar abundance of beryllium is deduced from high-resolution Kitt Peak observations of the 3130.43- and 3131.08-A lines of Be II interpreted by the method of spectrum synthesis. The results are in good agreement with those previously obtained by Grevesse (1968) and by Hauge and Engvold (1968) and indicate that in the photospheric layers, beryllium is depleted below the chondritic value by a factor of about two. It is found that the beryllium abundance is equal to logN(Be)/N(H) + 12 = 1.08 plus or minus 0.05.

  1. Desert water harvesting to benefit wildlife: a simple, cheap, and durable sub-surface water harvester for remote locations.

    PubMed

    Rice, William E

    2004-12-01

    A sub-surface desert water harvester was constructed in the sagebrush steppe habitat of south-central Idaho, U.S.A. The desert water harvester utilizes a buried micro-catchment and three buried storage tanks to augment water for wildlife during the dry season. In this region, mean annual precipitation (MAP) ranges between about 150-250 mm (6"-10"), 70% of which falls during the cold season, November to May. Mid-summer through early autumn, June through October, is the dry portion of the year. During this period, the sub-surface water harvester provides supplemental water for wildlife for 30-90 days, depending upon the precipitation that year. The desert water harvester is constructed with commonly available, "over the counter" materials. The micro-catchment is made of a square-shaped, 20 mL. "PERMALON" polyethylene pond liner (approximately 22.9 m x 22.9 m = 523 m2) buried at a depth of about 60 cm. A PVC pipe connects the harvester with two storage tanks and a drinking trough. The total capacity of the water harvester is about 4777 L (1262 U.S. gallons) which includes three underground storage tanks, a trough and pipes. The drinking trough is refined with an access ramp for birds and small animals. The technology is simple, cheap, and durable and can be adapted to other uses, e.g. drip irrigation, short-term water for small livestock, poultry farming etc. The desert water harvester can be used to concentrate and collect water from precipitation and run-off in semi-arid and arid regions. Water harvested in such a relatively small area will not impact the ground water table but it should help to grow small areas of crops or vegetables to aid villagers in self-sufficiency.

  2. Characterization and application of bioflocculant prepared by Rhodococcus erythropolis using sludge and livestock wastewater as cheap culture media.

    PubMed

    Peng, Lanyan; Yang, Chunping; Zeng, Guangming; Wang, Lu; Dai, Chuanhua; Long, Zhiyong; Liu, Hongyu; Zhong, Yuanyuan

    2014-08-01

    A new bioflocculant was produced by culturing Rhodococcus erythropolis in a cheap medium. When culture pH was 7.0, inoculum size was 2 % (v/v), Na2HPO4 concentration was 0.5 g L(-1), and the ratio of sludge/livestock wastewater was 7:1 (v/v), a maximum flocculating rate of 87.6 % could be achieved. Among 13 different kinds of pretreatments for sludge, the optimal one was the thermal-alkaline pretreatment. Different from a bioflocculant produced in a standard medium, this bioflocculant was effective over a wide pH range from 2 to 12 with flocculating rates higher than 98 %. Approximately, 1.6 g L(-1) of crude bioflocculant could be harvested using cold ethanol for extraction. This bioflocculant showed color removal rates up to 80 % when applied to direct and disperse dye solutions, but only 23.0 % for reactive dye solutions. Infrared spectrum showed that the bioflocculant contained functional groups such as -OH, -NH2, and -CONH2. Components in the bioflocculant consisted of 91.2 % of polysaccharides, 7.6 % of proteins, and 1.2 % of DNA. When the bioflocculant and copper sulfate (CuSO4) were used together for decolorization in actual dye wastewater, the optimum decolorization conditions were specified by the response surface methodology as pH 11, bioflocculant dosage of 40 mg/L, and CuSO4 80 mg/L, under which a decolorization rate of 93.9 % could be reached.

  3. THE SOLAR FLARE IRON ABUNDANCE

    SciTech Connect

    Phillips, K. J. H.; Dennis, B. R. E-mail: Brian.R.Dennis@nasa.gov

    2012-03-20

    The abundance of iron is measured from emission line complexes at 6.65 keV (Fe line) and 8 keV (Fe/Ni line) in RHESSI X-ray spectra during solar flares. Spectra during long-duration flares with steady declines were selected, with an isothermal assumption and improved data analysis methods over previous work. Two spectral fitting models give comparable results, viz., an iron abundance that is lower than previous coronal values but higher than photospheric values. In the preferred method, the estimated Fe abundance is A(Fe) = 7.91 {+-} 0.10 (on a logarithmic scale, with A(H) = 12) or 2.6 {+-} 0.6 times the photospheric Fe abundance. Our estimate is based on a detailed analysis of 1898 spectra taken during 20 flares. No variation from flare to flare is indicated. This argues for a fractionation mechanism similar to quiet-Sun plasma. The new value of A(Fe) has important implications for radiation loss curves, which are estimated.

  4. Abundance estimation and conservation biology

    USGS Publications Warehouse

    Nichols, J.D.; MacKenzie, D.I.

    2004-01-01

    Abundance is the state variable of interest in most population–level ecological research and in most programs involving management and conservation of animal populations. Abundance is the single parameter of interest in capture–recapture models for closed populations (e.g., Darroch, 1958; Otis et al., 1978; Chao, 2001). The initial capture–recapture models developed for partially (Darroch, 1959) and completely (Jolly, 1965; Seber, 1965) open populations represented efforts to relax the restrictive assumption of population closure for the purpose of estimating abundance. Subsequent emphases in capture–recapture work were on survival rate estimation in the 1970’s and 1980’s (e.g., Burnham et al., 1987; Lebreton et al.,1992), and on movement estimation in the 1990’s (Brownie et al., 1993; Schwarz et al., 1993). However, from the mid–1990’s until the present time, capture–recapture investigators have expressed a renewed interest in abundance and related parameters (Pradel, 1996; Schwarz & Arnason, 1996; Schwarz, 2001). The focus of this session was abundance, and presentations covered topics ranging from estimation of abundance and rate of change in abundance, to inferences about the demographic processes underlying changes in abundance, to occupancy as a surrogate of abundance. The plenary paper by Link & Barker (2004) is provocative and very interesting, and it contains a number of important messages and suggestions. Link & Barker (2004) emphasize that the increasing complexity of capture–recapture models has resulted in large numbers of parameters and that a challenge to ecologists is to extract ecological signals from this complexity. They offer hierarchical models as a natural approach to inference in which traditional parameters are viewed as realizations of stochastic processes. These processes are governed by hyperparameters, and the inferential approach focuses on these hyperparameters. Link & Barker (2004) also suggest that our attention

  5. Actinide abundances in ordinary chondrites

    USGS Publications Warehouse

    Hagee, B.; Bernatowicz, T.J.; Podosek, F.A.; Johnson, M.L.; Burnett, D.S.; Tatsumoto, M.

    1990-01-01

    Measurements of 244Pu fission Xe, U, Th, and light REE (LREE) abundances, along with modal petrographic determinations of phosphate abundances, were carried out on equilibrated ordinary chondrites in order to define better the solar system Pu abundance and to determine the degree of variation of actinide and LREE abundances. Our data permit comparison of the directly measured Pu/ U ratio with that determined indirectly as (Pu/Nd) ?? (Nd/U) assuming that Pu behaves chemically as a LREE. Except for Guaren??a, and perhaps H chondrites in general, Pu concentrations are similar to that determined previously for St. Se??verin, although less precise because of higher trapped Xe contents. Trapped 130Xe 136Xe ratios appear to vary from meteorite to meteorite, but, relative to AVCC, all are similar in the sense of having less of the interstellar heavy Xe found in carbonaceous chondrite acid residues. The Pu/U and Pu/Nd ratios are consistent with previous data for St. Se??verin, but both tend to be slightly higher than those inferred from previous data on Angra dos Reis. Although significant variations exist, the distribution of our Th/U ratios, along with other precise isotope dilution data for ordinary chondrites, is rather symmetric about the CI chondrite value; however, actinide/(LREE) ratios are systematically lower than the CI value. Variations in actinide or LREE absolute and relative abundances are interpreted as reflecting differences in the proportions and/or compositions of more primitive components (chondrules and CAI materials?) incorporated into different regions of the ordinary chondrite parent bodies. The observed variations of Th/U, Nd/U, or Ce/U suggest that measurements of Pu/U on any single equilibrated ordinary chondrite specimen, such as St. Se??verin, should statistically be within ??20-30% of the average solar system value, although it is also clear that anomalous samples exist. ?? 1990.

  6. Dehydration of highly concentrated solutions of fructose to 5-hydroxymethylfurfural in a cheap and sustainable choline chloride/carbon dioxide system.

    PubMed

    Liu, Fei; Barrault, Joël; De Oliveira Vigier, Karine; Jérôme, François

    2012-07-01

    Fête DES sciences: The dehydration of fructose and inulin to HMF is conveniently performed in a cheap and sustainable choline chloride/CO(2) deep eutectic solvent (DES) system. The medium is capable of converting high contents of fructose (>100 wt %) without affecting the yield of HMF (up to 72 %). The purity of the recovered HMF is >98%, and the reaction medium can be recycled.

  7. Element abundances at high redshift

    NASA Technical Reports Server (NTRS)

    Meyer, David M.; Welty, D. E.; York, D. G.

    1989-01-01

    Abundances of Si(+), S(+), Cr(+), Mn(+), Fe(_), and Zn(+) are considered for two absorption-line systems in the spectrum of the QSO PKS 0528 - 250. Zinc and sulfur are underabundant, relative to H, by a factor of 10 compared to their solar and Galactic interstellar abundances. The silicon-, chromium-, iron-, and nickel-to-hydrogen ratios are less than the solar values and comparable to the local interstellar ratios. A straightforward interpretation is that nucleosynthesis in these high-redshift systems has led to only about one-tenth as much heavy production as in the gas clouds around the sun, and that the amount of the observed underabundances attributable to grain depletion is small. The dust-to-gas ratio in these clouds is less than 8 percent of the Galactic value.

  8. Coronal abundances and their variation

    NASA Technical Reports Server (NTRS)

    Saba, Julia L. R.

    1994-01-01

    This contract supports the investigation of elemental abundances in the solar corona, principally through analysis of high-resolution software X-ray spectra from the Flat Crystal Spectrometer on NASA's Solar Maximum Mission. The goals of the study are a characterization of the mean values of relative abundances of elements accessible in the FCS data, and information on the extent and circumstances of their variability. This report is a summation of the data analysis and reporting activities which occurred since the last report, submitted two months early, in April 1994, to facilitate evaluation of the first year's progress for contract renewal. Hence this report covers the period 15 April 1994 - 15 December 1994. A list of publications resulting from this research is included.

  9. The CALIFA survey: Oxygen abundances

    NASA Astrophysics Data System (ADS)

    Sánchez, S. F.; Aff001

    We present here the last results we obtained on the spatial resolved analysis of the ionized gas of disk-dominated galaxies based on CALIFA data. CALIFA is an ongoing IFS survey of galaxies in the Local Univese (0.005 < z < 0.03) that has already obtained spectroscopic information up to ~2.5r e with a spatial resolution better than ~1 kpc for a total number of an statiscal sample of galaxies of different morphological types, covering the CM-diagram up to Mr<-18 mag. With nearly 2000 spectra obtained for each galaxy, CALIFA offer one of the best IFU data to study the starformation histories and chemical enrichment of galaxies. In this article we focus on the main results based on the analysis of the oxygen abundances based on the study of ionized gas in H ii regions and individual spaxels, and their relations with the global properties of galaxies. In summary we have found that: (1) the -Z relation does not present a secondary relation with the star-formation rate, when the abundance is measured at the effective radius; (2) the oxygen abundance present a strong correlation with the stellar surface density (Σ-Z relation); (3) the oxygen abundance profiles present three well defined regimes, (a) an overall negative radial gradient, between 0.5-2 r e , with a characteristic slope of α O/H ~-0.1 dex/r e , (b) an universal flatenning beyond >2r e and (c) an inner drop at <0.5r e which presence depends on the mass. All these results indicates that disk-galaxies present an overall inside-out growth, although with clear deviations from this simple scenario.

  10. The solar abundance of thulium

    NASA Technical Reports Server (NTRS)

    Ross, J. E.; Aller, L. H.

    1974-01-01

    Consideration of one relatively unblended line of the solar spectrum, namely, the 3131.258-A line of Tm II, which yields a thulium abundance of 0.80 plus or minus 0.10 with the Corliss and Bozman (1962) f-value. The uncertainty of this figure is discussed in conjunction with the contradictory findings of some other investigators. The need for further detailed study of the lanthanides by the method of spectrum synthesis is pointed out.

  11. Chlorine Abundances in Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Bogard, D.D.; Garrison, D.H.; Park, J.

    2009-01-01

    Chlorine measurements made in martian surface rocks by robotic spacecraft typically give Chlorine (Cl) abundances of approximately 0.1-0.8%. In contrast, Cl abundances in martian meteorites appear lower, although data is limited, and martian nakhlites were also subjected to Cl contamination by Mars surface brines. Chlorine abundances reported by one lab for whole rock (WR) samples of Shergotty, ALH77005, and EET79001 range 108-14 ppm, whereas Cl in nakhlites range 73-1900 ppm. Measurements of Cl in various martian weathering phases of nakhlites varied 0.04-4.7% and reveal significant concentration of Cl by martian brines Martian meteorites contain much lower Chlorine than those measured in martian surface rocks and give further confirmation that Cl in these surface rocks was introduced by brines and weathering. It has been argued that Cl is twice as effective as water in lowering the melting point and promoting melting at shallower martian depths, and that significant Cl in the shergottite source region would negate any need for significant water. However, this conclusion was based on experiments that utilized Cl concentrations more analogous to martian surface rocks than to shergottite meteorites, and may not be applicable to shergottites.

  12. Electrical injury

    MedlinePlus

    ... damage, especially to the heart, muscles, or brain. Electric current can cause injury in three ways: Cardiac arrest ... How long you were in contact with the electricity How the electricity moved through your body Your ...

  13. Electricity Customers

    EPA Pesticide Factsheets

    This page discusses key sectors and how they use electricity. Residential, commercial, and industrial customers each account for roughly one-third of the nation’s electricity use. The transportation sector also accounts for a small fraction of electricity.

  14. Elemental Abundances from Very Low Abundance HII Regions

    NASA Astrophysics Data System (ADS)

    Skillman, Evan D.; Terlevich, Roberto J.; Terlevich, Elena

    1992-12-01

    In 1987 we initiated a program to mitigate the deficiency of known low metallicity galaxies. Following our discoveries of very low abundance H II regions in nearby dwarf galaxies (Skillman et al. 1988, 1989a,b), we used the IDS on the INT to to collect spectra of dwarf galaxies in the Second Byurakan Survey (SBS) of UV excess galaxies. Our survey of over 40 SBS galaxies was completed in January 1990 and we have identified roughly one dozen very low metallicity H II galaxies. Now, with a significant sample of these galaxies, several observational programs are possible; foremost of these is the measurement of the primordial helium abundance (eg., Pagel et al. 1992). We report here on observations from March 1991 and 1992 using the ISIS spectrograph on the WHT to obtain very high quality spectra of 8 of these newly discovered metal-poor galaxies. The ISIS double spectrograph allows simultaneous observations of the blue (3600 - 5100 Angstroms) and red (6300 - 6800 Angstroms). Thus, He, N, O, Ne and S abundances can be derived with relatively small observational uncertainties. We compare our new observations with those in the literature. Our preliminary analysis indicates a slightly larger scatter in He/H at low O/H than had been seen previously. The small scatter may have been due simply to the paucity of observations at low metallicity. References: Pagel, B.E.J., Simonson, E.A., Terlevich, R.J., & Edmunds, M.G. 1992, MNRAS, 255, 325 Skillman, E.D., Kennicutt, R.C., & Hodge, P.W. 1989a, ApJ, 347, 875 Skillman, E.D., Melnick, J., Terlevich, R., & Moles, M. 1988, A&A, 196, 31 Skillman, E.D., Terlevich, R., & Melnick, J. 1989b, MNRAS, 240, 563

  15. The Abundance of Interstellar Fluorine

    NASA Technical Reports Server (NTRS)

    Lauroesch, James T.

    2005-01-01

    The primary objective of this program was to obtain FUSE observations of the interstellar absorption lines of F I at 951 and 954 Angstroms to derive the abundance of fluorine toward the star HD 164816. The nucleosynthetic source(s) of fluorine are still a matter of debate - the present day abundance of fluorine can potentially constrain models for pulsationally driven dredge-up in asymptotic giant branch stars. An accurate measure for the depletion behavior of fluorine will determine whether it may be detectable in QSO absorption line systems - an unambiguous detection of fluorine at suitably high redshifts would provide the best evidence to date for the neutrino process in massive stars. Furthermore, due to its extreme reactivity, measurement of the gas-phase interstellar fluorine abundance is important for models of grain chemistry. Despite the importance of measuring the interstellar fluorine abundance, at the time of our proposal only one previous detection has been made due to the low relative abundance of fluorine, the lack of lines outside the far-UV, and the blending of the available F I transitions with lines of Hz. The star HD 164816 is associated with the Lagoon nebula (M8), and at a distance of approximately 1.5 kpc probes both distant and local gas. Beginning April 8th, 2004 FUSE FP-Split observations of the star HD 164816 were obtained for this program. This data became available in the FUSE data archive May 21, 2004, and these observations were then downloaded and we began our analysis. Our analysis procedure has involved (1) fitting stellar models to the FUSE spectra, (2) using the multiple lines of Hz and N I at other wavelengths in the FUSE bandpass to derive column densities for the lines of H2 and N I which are blended with the F I features at 951 and 954 angstroms (3) the measurement of the column densities of F I and the species O I and C1 I which are important species for the dis-entangling of dust and nucleosynthetic effects. As discussed in

  16. Abundance measurements in stellar environments

    SciTech Connect

    Leone, F.

    2014-05-09

    Most of what we know about stars, and systems of stars, is derived from the analysis of their electromagnetic radiation. This lesson is an attempt to describe to Physicists, without any Astrophysical background, the framework to understand the present status of abundance determination in stellar environments and its limit. These notes are dedicated to the recently passed, November 21, 2013, Prof. Dimitri Mihalas who spent his life confuting the 19th century positivist philosopher Auguste Comte who stated that we shall not at all be able to determine the chemical composition of stars.

  17. Abundance measurements in stellar environments

    NASA Astrophysics Data System (ADS)

    Leone, F.

    2014-05-01

    Most of what we know about stars, and systems of stars, is derived from the analysis of their electromagnetic radiation. This lesson is an attempt to describe to Physicists, without any Astrophysical background, the framework to understand the present status of abundance determination in stellar environments and its limit. These notes are dedicated to the recently passed, November 21, 2013, Prof. Dimitri Mihalas who spent his life confuting the 19th century positivist philosopher Auguste Comte who stated that we shall not at all be able to determine the chemical composition of stars.

  18. The solar abundance of Oxygen

    NASA Astrophysics Data System (ADS)

    Grevesse, N.

    2009-07-01

    With Martin Asplund (Max Planck Institute of Astrophysics, Garching) and Jacques Sauval (Observatoire Royal de Belgique, Brussels) I recently published detailed reviews on the solar chemical composition ({Asplund et al. 2005}, {Grevesse et al. 2007}). A new one, with Pat Scott (Stockholm University) as additional co-author, will appear in Annual Review of Astronomy and Astrophysics ({Asplund et al. 2009}). Here we briefly analyze recent works on the solar abundance of Oxygen and recommend a value of 8.70 in the usual astronomical scale.

  19. Electrical Curriculum.

    ERIC Educational Resources Information Center

    EASTCONN Regional Educational Services Center, North Windham, CT.

    The purpose of this electrical program is to prepare students for service, repair, and assembly of electrically driven or controlled devices. The program theory and application includes mechanical assemblies, electrical circuitry, and electronic principles including basic digital circuitry. The electrical program manual includes the following…

  20. Influence of Coronal Abundance Variations

    NASA Technical Reports Server (NTRS)

    Gurman, Joseph (Technical Monitor); DeLuca, Edward

    2005-01-01

    During the final year of this program we concentrated on understanding the how to constrain the models with the best available observations. Work on developing accurate temperature and density diagnostics fkom TRACE and CDS together with constrained fits of non-potential force free fields will be extremely useful in the guiding the next generation of coronal models. The program has produced three fully operation numerical codes that model multi-species of ions in coronal loops: Static models and constant flow models. The time dependent numerical models have not been completed. We have extended the steady flow investigations to study the effect these flows have on coronal structure as observed with TRACE. Coronal observations derive from heavy-ion emission; thus, we focus on the extent to which flow may modify coronal abundances by examining the heavy-ion abundance stratification within long-lived loops. We discuss the magnitudes of the physical effects modeled and compare simulated results with TRACE observations. These results can have a profound effect on the interpretation of TRACE observations.

  1. Abundances in Hot Evolved Stars

    NASA Astrophysics Data System (ADS)

    Werner, Klaus; Rauch, Thomas; Kruk, Jeffrey W.

    2009-05-01

    The hydrogen-deficiency in extremely hot post-AGB stars of spectral class PG1159 is probably caused by a (very) late helium-shell flash or a AGB final thermal pulse that consumes the hydrogen envelope, exposing the usually-hidden intershell region. Thus, the photospheric element abundances of these stars allow us to draw conclusions about details of nuclear burning and mixing processes in the precursor AGB stars. We compare predicted element abundances to those determined by quantitative spectral analyses performed with advanced non-LTE model atmospheres. A good qualitative and quantitative agreement is found for many species (He, C, N, O, Ne, F, Si, Ar) but discrepancies for others (P, S, Fe) point at shortcomings in stellar evolution models for AGB stars. Almost all of the chemical trace elements in these hot stars can only be identified in the UV spectral range. The Far Ultraviolet Spectroscopic Explorer and the Hubble Space Telescope played a crucial role for this research.

  2. Solar-system abundances of the elements

    NASA Technical Reports Server (NTRS)

    Anders, E.; Ebihara, M.

    1982-01-01

    Elemental analyses of the Ogueil Cl meteorite and all previous Cl chondrite analyses were employed to develop a new solar system abundance table, including the standard deviation and number of analyses for each element. The table also comprises the abundances of radioactive and radiogenic nuclides at the present and 4.55 AE ago, as well as abundances by weight in a typical Cl chondrite. The new abundances were within 20% of those determined by Cameron (1982), except for 14 cases in the range 20-50%, and 5 over 50%. The solar abundances were compared with the Cl abundances, showing a total of only 7 disagreements. No significant discrepancies were detected in the major cosmochemical groups, and a smooth trend was found in the abundances of odd-A nuclides. The new set is interpreted as accurate to 10%, with the Cl chondrites matching the primordial solar system abundances to at most 10% deviation.

  3. Hematite Abundance Map at Echo

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image shows the hematite abundance map for a portion of the Meridiani Planum rock outcrop near where the Mars Exploration Rover Opportunity landed. It was acquired by the rover's miniature thermal emission spectrometer instrument from a spot called 'Echo.' Portions of the inner crater wall in this region appear rich in hematite (red). The sharp boundary from hematite-rich to hematite-poor (yellow and green) surfaces corresponds to a change in the surface texture and color. The hematite-rich surfaces have ripple-like forms suggesting wind transported hematite to these surfaces. The bounce marks produced during landing at the base of the slope on the left are low in hematite (blue). The hematite grains that originally covered the surface were pushed below the surface by the lander, exposing a soil that has less hematite.

  4. Quick, easy, cheap, effective, rugged, and safe sample preparation approach for pesticide residue analysis using traditional detectors in chromatography: A review.

    PubMed

    Rahman, Md Musfiqur; Abd El-Aty, A M; Kim, Sung-Woo; Shin, Sung Chul; Shin, Ho-Chul; Shim, Jae-Han

    2017-01-01

    In pesticide residue analysis, relatively low-sensitivity traditional detectors, such as UV, diode array, electron-capture, flame photometric, and nitrogen-phosphorus detectors, have been used following classical sample preparation (liquid-liquid extraction and open glass column cleanup); however, the extraction method is laborious, time-consuming, and requires large volumes of toxic organic solvents. A quick, easy, cheap, effective, rugged, and safe method was introduced in 2003 and coupled with selective and sensitive mass detectors to overcome the aforementioned drawbacks. Compared to traditional detectors, mass spectrometers are still far more expensive and not available in most modestly equipped laboratories, owing to maintenance and cost-related issues. Even available, traditional detectors are still being used for analysis of residues in agricultural commodities. It is widely known that the quick, easy, cheap, effective, rugged, and safe method is incompatible with conventional detectors owing to matrix complexity and low sensitivity. Therefore, modifications using column/cartridge-based solid-phase extraction instead of dispersive solid-phase extraction for cleanup have been applied in most cases to compensate and enable the adaptation of the extraction method to conventional detectors. In gas chromatography, the matrix enhancement effect of some analytes has been observed, which lowers the limit of detection and, therefore, enables gas chromatography to be compatible with the quick, easy, cheap, effective, rugged, and safe extraction method. For liquid chromatography with a UV detector, a combination of column/cartridge-based solid-phase extraction and dispersive solid-phase extraction was found to reduce the matrix interference and increase the sensitivity. A suitable double-layer column/cartridge-based solid-phase extraction might be the perfect solution, instead of a time-consuming combination of column/cartridge-based solid-phase extraction and

  5. Recent progress on earth abundant hydrogen evolution reaction and oxygen evolution reaction bifunctional electrocatalyst for overall water splitting in alkaline media

    NASA Astrophysics Data System (ADS)

    Jamesh, Mohammed Ibrahim

    2016-11-01

    Electrochemical water-splitting is one of the promising ways for producing clean chemical fuel (Hydrogen) while cheap-earth-abundant-bifunctional-electrocatalyst is one of the possible way for improving the overall cost efficiency of water-splitting. This paper reviews the chemical state, hydrogen and oxygen evolution reaction activity in alkaline media, overall water-splitting performance in alkaline media, stability, and possible-factors for improving its efficiency of various kinds of recently reported electrocatalyst such as Ni-P, Co-P, Ni-Co-P, graphene-Co-P, O/N/C-Co/Ni, Ni-S, B-Ni/Co, Ni-Co, Mo, Se, Fe, Mn/Zn/Ti, and metal-free based earth-abundant-bifunctional-electrocatalyst. This paper also reviews and highlights the remarkable water splitting performance of the earth-abundant-bifunctional-electrocatalyst those exhibit better or well comparable with Pt/C//RuO2.

  6. Electrical Generation.

    ERIC Educational Resources Information Center

    Science and Children, 1990

    1990-01-01

    Described are two activities designed to help children investigate electrical charges, electric meters, and electromagnets. Included are background information, a list of materials, procedures, and follow-up questions. Sources of additional information are cited. (CW)

  7. Surface abundances of ON stars

    NASA Astrophysics Data System (ADS)

    Martins, F.; Simón-Díaz, S.; Palacios, A.; Howarth, I.; Georgy, C.; Walborn, N. R.; Bouret, J.-C.; Barbá, R.

    2015-06-01

    Context. Massive stars burn hydrogen through the CNO cycle during most of their evolution. When mixing is efficient or when mass transfer in binary systems occurs, chemically processed material is observed at the surface of O and B stars. Aims: ON stars show stronger lines of nitrogen than morphologically normal counterparts. Whether this corresponds to the presence of material processed through the CNO cycle is not known. Our goal is to answer this question. Methods: We performed a spectroscopic analysis of a sample of ON stars with atmosphere models. We determined the fundamental parameters as well as the He, C, N, and O surface abundances. We also measured the projected rotational velocities. We compared the properties of the ON stars to those of normal O stars. Results: We show that ON stars are usually rich in helium. Their CNO surface abundances are fully consistent with predictions of nucleosynthesis. ON stars are more chemically evolved and rotate - on average - faster than normal O stars. Evolutionary models including rotation cannot account for the extreme enrichment observed among ON main sequence stars. Some ON stars are members of binary systems, but others are single stars as indicated by stable radial velocities. Mass transfer is therefore not a simple explanation for the observed chemical properties. Conclusions: We conclude that ON stars show extreme chemical enrichment at their surface, consistent with nucleosynthesis through the CNO cycle. Its origin is not clear at present. Based on observations obtained 1) at the Anglo-Australian Telescope; 2) at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii; 3) at the ESO/La Silla Observatory under programs 081.D-2008, 083.D-0589, 086.D-0997; 4) the Nordic Optical Telescope, operated on the island of La

  8. A facile and cheap coating method to prepare SiO2/melamine-formaldehyde and SiO2/urea-formaldehyde composite microspheres

    NASA Astrophysics Data System (ADS)

    Mou, Shaoyan; Lu, Yao; Jiang, Yong

    2016-10-01

    A facile and cheap coating route has been explored to prepare SiO2/melamine formaldehyde hybrid particles. In this process, SiO2 microspheres act as seeds, and a polycondensation reaction occurs on the surface of melamine-formaldehyde pre-polymers. Formaldehyde is essential in this coating process because it acts as a novel and cheap surface modification agent instead of a traditional silane coupling agent. Ultrasonic method is used in the synthesis to avoid aggregation of nano- and micro-particles. Most of the traditional methods preparing composite microspheres were implemented under difficult conditions and at high costs. The improved coating method is much more able to provide a convenient path for researchers and engineers to more easily and economically perform experiments and engage in manufacturing. To verify this convenient method, SiO2/urea-formaldehyde composite microspheres were also prepared. SEM images show that the surfaces of all the products are smooth and well-shaped.

  9. Statistical evaluation and modeling of cheap substrate-based cultivation medium of Chlorella vulgaris to enhance microalgae lipid as new potential feedstock for biolubricant.

    PubMed

    Mohammad Mirzaie, M A; Kalbasi, M; Mousavi, S M; Ghobadian, B

    2016-05-18

    Chlorella vulgaris (C. vulgaris) microalga was investigated as a new potential feedstock for the production of biodegradable lubricant. In order to enhance microalgae lipid for biolubricant production, mixotrophic growth of C. vulgaris was optimized using statistical analysis of Plackett-Burman (P-B) and response surface methodology (RSM). A cheap substrate-based medium of molasses and corn steep liquor (CSL) was used instead of expensive mineral salts to reduce the total cost of microalgae production. The effects of molasses and CSL concentration (cheap substrates) and light intensity on the growth of microalgae and their lipid content were analyzed and modeled. Designed models by RSM showed good compatibility with a 95% confidence level when compared to the cultivation system. According to the models, optimal cultivation conditions were obtained with biomass productivity of 0.123 g L(-1) day(-1) and lipid dry weight of 0.64 g L(-1) as 35% of dry weight of C. vulgaris. The extracted microalgae lipid presented useful fatty acid for biolubricant production with viscosities of 42.00 cSt at 40°C and 8.500 cSt at 100°C, viscosity index of 185, flash point of 185°C, and pour point of -6°C. These properties showed that microalgae lipid could be used as potential feedstock for biolubricant production.

  10. Cheap, gram-scale fabrication of BN nanosheets via substitution reaction of graphite powders and their use for mechanical reinforcement of polymers.

    PubMed

    Liu, Fei; Mo, Xiaoshu; Gan, Haibo; Guo, Tongyi; Wang, Xuebin; Chen, Bin; Chen, Jun; Deng, Shaozhi; Xu, Ningsheng; Sekiguchi, Takashi; Golberg, Dmitri; Bando, Yoshio

    2014-02-27

    As one of the most important two-dimensional (2D) materials, BN nanosheets attracted intensive interest in the past decade. Although there are many methods suitable for the preparation of BN sheets, finding a cheap and nontoxic way for their mass and high-quality production is still a challenge. Here we provide a highly effective and cheap way to synthesize gram-scale-level well-structured BN nanosheets from many common graphite products as source materials. Single-crystalline multi-layered BN sheets have a mean lateral size of several hundred nanometers and a thickness ranging from 5 nm to 40 nm. Cathodoluminescence (CL) analysis shows that the structures exhibit a near band-edge emission and a broad emission band from 300 nm to 500 nm. Utilization of nanosheets for the reinforcement of polymers revealed that the Young's modulus of BN/PMMA composite had increased to 1.56 GPa when the BN's fraction was only 2 wt.%, thus demonstrating a 20% gain compared to a blank PMMA film. It suggests that the BN nanosheet is an ideal mechanical reinforcing material for polymers. In addition, this easy and nontoxic substitution method may provide a universal route towards high yields of other 2D materials.

  11. Cheap, Gram-Scale Fabrication of BN Nanosheets via Substitution Reaction of Graphite Powders and Their Use for Mechanical Reinforcement of Polymers

    NASA Astrophysics Data System (ADS)

    Liu, Fei; Mo, Xiaoshu; Gan, Haibo; Guo, Tongyi; Wang, Xuebin; Chen, Bin; Chen, Jun; Deng, Shaozhi; Xu, Ningsheng; Sekiguchi, Takashi; Golberg, Dmitri; Bando, Yoshio

    2014-02-01

    As one of the most important two-dimensional (2D) materials, BN nanosheets attracted intensive interest in the past decade. Although there are many methods suitable for the preparation of BN sheets, finding a cheap and nontoxic way for their mass and high-quality production is still a challenge. Here we provide a highly effective and cheap way to synthesize gram-scale-level well-structured BN nanosheets from many common graphite products as source materials. Single-crystalline multi-layered BN sheets have a mean lateral size of several hundred nanometers and a thickness ranging from 5 nm to 40 nm. Cathodoluminescence (CL) analysis shows that the structures exhibit a near band-edge emission and a broad emission band from 300 nm to 500 nm. Utilization of nanosheets for the reinforcement of polymers revealed that the Young's modulus of BN/PMMA composite had increased to 1.56 GPa when the BN's fraction was only 2 wt.%, thus demonstrating a 20% gain compared to a blank PMMA film. It suggests that the BN nanosheet is an ideal mechanical reinforcing material for polymers. In addition, this easy and nontoxic substitution method may provide a universal route towards high yields of other 2D materials.

  12. Cheap, Gram-Scale Fabrication of BN Nanosheets via Substitution Reaction of Graphite Powders and Their Use for Mechanical Reinforcement of Polymers

    PubMed Central

    Liu, Fei; Mo, Xiaoshu; Gan, Haibo; Guo, Tongyi; Wang, Xuebin; Chen, Bin; Chen, Jun; Deng, Shaozhi; Xu, Ningsheng; Sekiguchi, Takashi; Golberg, Dmitri; Bando, Yoshio

    2014-01-01

    As one of the most important two-dimensional (2D) materials, BN nanosheets attracted intensive interest in the past decade. Although there are many methods suitable for the preparation of BN sheets, finding a cheap and nontoxic way for their mass and high-quality production is still a challenge. Here we provide a highly effective and cheap way to synthesize gram-scale-level well-structured BN nanosheets from many common graphite products as source materials. Single-crystalline multi-layered BN sheets have a mean lateral size of several hundred nanometers and a thickness ranging from 5 nm to 40 nm. Cathodoluminescence (CL) analysis shows that the structures exhibit a near band-edge emission and a broad emission band from 300 nm to 500 nm. Utilization of nanosheets for the reinforcement of polymers revealed that the Young's modulus of BN/PMMA composite had increased to 1.56 GPa when the BN's fraction was only 2 wt.%, thus demonstrating a 20% gain compared to a blank PMMA film. It suggests that the BN nanosheet is an ideal mechanical reinforcing material for polymers. In addition, this easy and nontoxic substitution method may provide a universal route towards high yields of other 2D materials. PMID:24572725

  13. Observing chemical abundances in comets

    NASA Technical Reports Server (NTRS)

    Delsemme, A. H.

    1981-01-01

    The atomic resonance lines of the major elements were observed in the atmospheres of a few comets, by using vacuum ultraviolet spectrographs on board rockets or orbiting observatories. Dust-to-gas ratios were also deduced for two comets through a Finson-Probstein's analysis of their dust-tail isophotes. The geometric albedo of the dust for the phase angle alpha of the observations is not accurately known but, the dust-to-gas ratio is not overly sensitive to the actual value of this albedo. Infrared observations of the dust head of some comets show that the bulk of cometary dust must be silicates, although a minor component (5-10 percent) of carbon compounds is rather likely, because of poor dielectric properties of the grains. This interpretation is confirmed by the fact that interplanetary dust probably of cometary origin, that was collected in the stratosphere by NASA-U2 Spacecraft, is chondritic in nature. Metal abundances in the head of a sungrazing comet support the chondritic hypothesis.

  14. Water purification by electrical discharges

    NASA Astrophysics Data System (ADS)

    Arif Malik, Muhammad; Ghaffar, Abdul; Akbar Malik, Salman

    2001-02-01

    There is a continuing need for the development of effective, cheap and environmentally friendly processes for the disinfection and degradation of organic pollutants from water. Ozonation processes are now replacing conventional chlorination processes because ozone is a stronger oxidizing agent and a more effective disinfectant without any side effects. However, the fact that the cost of ozonation processes is higher than chlorination processes is their main disadvantage. In this paper recent developments targeted to make ozonation processes cheaper by improving the efficiency of ozone generation, for example, by incorporation of catalytic packing in the ozone generator, better dispersion of ozone in water and faster conversion of dissolved ozone to free radicals are described. The synthesis of ozone in electrical discharges is discussed. Furthermore, the generation and plasma chemical reactions of several chemically active species, such as H2O2, Obullet, OHbullet, HO2bullet, O3*, N2*, e-, O2-, O-, O2+, etc, which are produced in the electrical discharges are described. Most of these species are stronger oxidizers than ozone. Therefore, water treatment by direct electrical discharges may provide a means to utilize these species in addition to ozone. Much research and development activity has been devoted to achieve these targets in the recent past. An overview of these techniques and important developments that have taken place in this area are discussed. In particular, pulsed corona discharge, dielectric barrier discharge and contact glow discharge electrolysis techniques are being studied for the purpose of cleaning water. The units based on electrical discharges in water or close to the water level are being tested at industrial-scale water treatment plants.}

  15. Electric vehicles

    NASA Astrophysics Data System (ADS)

    1990-03-01

    Quiet, clean, and efficient, electric vehicles (EVs) may someday become a practical mode of transportation for the general public. Electric vehicles can provide many advantages for the nation's environment and energy supply because they run on electricity, which can be produced from many sources of energy such as coal, natural gas, uranium, and hydropower. These vehicles offer fuel versatility to the transportation sector, which depends almost solely on oil for its energy needs. Electric vehicles are any mode of transportation operated by a motor that receives electricity from a battery or fuel cell. EVs come in all shapes and sizes and may be used for different tasks. Some EVs are small and simple, such as golf carts and electric wheel chairs. Others are larger and more complex, such as automobile and vans. Some EVs, such as fork lifts, are used in industries. In this fact sheet, we will discuss mostly automobiles and vans. There are also variations on electric vehicles, such as hybrid vehicles and solar-powered vehicles. Hybrid vehicles use electricity as their primary source of energy, however, they also use a backup source of energy, such as gasoline, methanol or ethanol. Solar-powered vehicles are electric vehicles that use photovoltaic cells (cells that convert solar energy to electricity) rather than utility-supplied electricity to recharge the batteries. These concepts are discussed.

  16. A comparison of depletion versus equalization for reducing high-abundance proteins in human serum.

    PubMed

    Fernández, Carolina; Santos, Hugo M; Ruíz-Romero, Cristina; Blanco, Francisco J; Capelo-Martínez, José-Luis

    2011-11-01

    In this work three methods to diminish the content of most highly abundant proteins in human serum have been studied and compared. Protein depletion with ACN or DTT and protein equalization with the ProteoMiner(™) (PM) have been assessed by 1-D gel electrophoresis and MS. After treatment 5, 18 and 9 major proteins within the 20 most abundant proteins in serum were identified for the ACN, DTT and PM methods, respectively. The ACN method was efficient for depleting high molecular weight proteins, over 75 KDa, resulting in 10±4% (n=3) of the total protein content remaining in the depleted serum. In addition, 75% of the proteins belonging to the group of the 20 most abundant proteins were not detected, making this depletion strategy a cheap alternative to expensive commercial tools regularly used for removing high abundance proteins from serum. The ACN extract was found rich in apolipoproteins. The dithithreitol method promotes the precipitation of proteins rich in disulfide bonds, mainly albumin, with 73±7% (n=3) of the total protein content remaining in the depleted serum, which was found rich in immunoglobulins. The PM method compresses the dynamic range of the serum proteins, rendering an extract containing 16±2% (n=3) of the total initial protein content. The extract was found to be rich in both apolipoproteins and immunoglobulins. As a general rule the DTT and PM methods provide a compression of the dynamic range of serum protein concentrations while the ACN method allows an effective depletion of the protein fraction above 72 KDa.

  17. Chemoselective single-site Earth-abundant metal catalysts at metal–organic framework nodes

    PubMed Central

    Manna, Kuntal; Ji, Pengfei; Lin, Zekai; Greene, Francis X.; Urban, Ania; Thacker, Nathan C.; Lin, Wenbin

    2016-01-01

    Earth-abundant metal catalysts are critically needed for sustainable chemical synthesis. Here we report a simple, cheap and effective strategy of producing novel earth-abundant metal catalysts at metal–organic framework (MOF) nodes for broad-scope organic transformations. The straightforward metalation of MOF secondary building units (SBUs) with cobalt and iron salts affords highly active and reusable single-site solid catalysts for a range of organic reactions, including chemoselective borylation, silylation and amination of benzylic C–H bonds, as well as hydrogenation and hydroboration of alkenes and ketones. Our structural, spectroscopic and kinetic studies suggest that chemoselective organic transformations occur on site-isolated, electron-deficient and coordinatively unsaturated metal centres at the SBUs via σ-bond metathesis pathways and as a result of the steric environment around the catalytic site. MOFs thus provide a novel platform for the development of highly active and affordable base metal catalysts for the sustainable synthesis of fine chemicals. PMID:27574182

  18. Primordial abundance of 40Ar

    NASA Astrophysics Data System (ADS)

    Sripada, V. S. Murty

    Primordial abundance of the isotope (40) Ar is still not known accurately. Recent results from Genesis could also not provide (40) Ar/ (36) Ar value of solar wind, due mainly to the overwhelming (40) Ar blank. A major part of (40) Ar is contributed by the radioactive decay of (40) K (half life = 1.25 Ga), even in the nebula, as the nebula grew old. Any attempt to determine this quantity needs a sample that satisfies the following criteria: A primitive mineral/phase that formed very early in the nebula, that can trap a large amount of noble gas (Ar); and a phase that acquires minimum amount (or total absence) of in situ produced components (cosmogenic and radiogenic) of Ar. Carbon phases in the ureilite meteorites and Phase Q from chondrites best fit this criteria. The minimum (40) Ar/ (36) Ar value so far observed in Phase Q is 0.2. Also, the relatively lower value of 1.035±±0.002 for trapped (129) Xe/ (132) Xe in ureilites, as compared to 1.042±±0.002 in Phase Q suggests that trapping of gases in ureilites might have predated that of Phase Q. If this interpretation is valid, ureilites are a better host of most primitive nebular Ar. Earlier attempts on ureilite studies in 1970s have yielded the lowest (40) Ar/ (36) Ar ratio in the meteorite Dayalpur, the major uncertainty for this value mostly coming from blank correction for (40) Ar/ (36) Ar. Recent developments in low blank extraction systems and more sensitive multi-collector noble gas mass spectrometers, as compared to 1970s have prompted us to make a fresh attempt in measuring this important quantity. We have analysed a number of ureilite acid residues by stepwise temperature extraction, using both pyrolysis and combustion techniques, for Ar to ascertain the trapped (40) Ar/ (36) Ar ratio in the solar nebula. These acid residues are mostly made of C rich phases, with only trace amounts of K (radiogenic parent of (40) Ar) and target elements for the production of cosmogenic Ar component. They mostly contain

  19. Abundance of introduced species at home predicts abundance away in herbaceous communities

    USGS Publications Warehouse

    Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

    2011-01-01

    Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

  20. Abundance of introduced species at home predicts abundance away in herbaceous communities.

    PubMed

    Firn, Jennifer; Moore, Joslin L; MacDougall, Andrew S; Borer, Elizabeth T; Seabloom, Eric W; HilleRisLambers, Janneke; Harpole, W Stanley; Cleland, Elsa E; Brown, Cynthia S; Knops, Johannes M H; Prober, Suzanne M; Pyke, David A; Farrell, Kelly A; Bakker, John D; O'Halloran, Lydia R; Adler, Peter B; Collins, Scott L; D'Antonio, Carla M; Crawley, Michael J; Wolkovich, Elizabeth M; La Pierre, Kimberly J; Melbourne, Brett A; Hautier, Yann; Morgan, John W; Leakey, Andrew D B; Kay, Adam; McCulley, Rebecca; Davies, Kendi F; Stevens, Carly J; Chu, Cheng-Jin; Holl, Karen D; Klein, Julia A; Fay, Philip A; Hagenah, Nicole; Kirkman, Kevin P; Buckley, Yvonne M

    2011-03-01

    Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

  1. Electrical stator

    DOEpatents

    Fanning, Alan W.; Olich, Eugene E.

    1994-01-01

    An electrical stator of an electromagnetic pump includes first and second spaced apart coils each having input and output terminals for carrying electrical current. An elongate electrical connector extends between the first and second coils and has first and second opposite ends. The connector ends include respective slots receiving therein respective ones of the coil terminals to define respective first and second joints. Each of the joints includes a braze filler fixedly joining the connector ends to the respective coil terminals for carrying electrical current therethrough.

  2. Electric propulsion

    NASA Astrophysics Data System (ADS)

    Garrison, Philip W.

    Electric propulsion (EP) is an attractive option for unmanned orbital transfer vehicles (OTV's). Vehicles with solar electric propulsion (SEP) could be used routinely to transport cargo between nodes in Earth, lunar, and Mars orbit. Electric propulsion systems are low-thrust, high-specific-impulse systems with fuel efficiencies 2 to 10 times the efficiencies of systems using chemical propellants. The payoff for this performance can be high, since a principal cost for a space transportation system is that of launching to low Earth orbit (LEO) the propellant required for operations between LEO and other nodes. Several aspects of electric propulsion, including candidate systems and the impact of using nonterrestrial materials, are discussed.

  3. Adaptation and Validation of QUick, Easy, New, CHEap, and Reproducible (QUENCHER) Antioxidant Capacity Assays in Model Products Obtained from Residual Wine Pomace.

    PubMed

    Del Pino-García, Raquel; García-Lomillo, Javier; Rivero-Pérez, María D; González-SanJosé, María L; Muñiz, Pilar

    2015-08-12

    Evaluation of the total antioxidant capacity of solid matrices without extraction steps is a very interesting alternative for food researchers and also for food industries. These methodologies have been denominated QUENCHER from QUick, Easy, New, CHEap, and Reproducible assays. To demonstrate and highlight the validity of QUENCHER (Q) methods, values of Q-method validation were showed for the first time, and they were tested with products of well-known different chemical properties. Furthermore, new QUENCHER assays to measure scavenging capacity against superoxide, hydroxyl, and lipid peroxyl radicals were developed. Calibration models showed good linearity (R(2) > 0.995), proportionality and precision (CV < 6.5%), and acceptable detection limits (<20.4 nmol Trolox equiv). The presence of ethanol in the reaction medium gave antioxidant capacity values significantly different from those obtained with water. The dilution of samples with powdered cellulose was discouraged because possible interferences with some of the matrices analyzed may take place.

  4. Lithosphere-to-Ionosphere Plug-and-Play Architecture (LION-PNP): Sensor Networking Made Cheap and Easy

    NASA Astrophysics Data System (ADS)

    Darling, N.; Mendez, J. S.; Manes, C.

    2013-12-01

    The lack of rapidly reconfigurable and easily deployable instrumentation packages often results in information loss during unannounced or time-critical geophysical events such as spaceweather flare-ups, earthquakes, volcanic eruptions, and tsunamis. While increasingly powerful and sensitive sensor technologies have been created in the last years to study our planet, robust, yet simple and cost-effective, mechanical, electrical, and data interfaces between these devices and the user (scientist) have yet to be developed. To address this problem, we present the LIthosphere-to-IOnosphere Plug-aNd-Play architecture (LION-PNP), a complete, low cost integration protocol for space, atmospheric, and terrestrial sensor networks. Similar to the USB plug-and-play protocols created for personal computers, LION-PNP offers geophysicists and space scientists the ability to assemble and operate complex sensor packages by simply 'plugging' devices (magnetometers, seismometers, GPS, spectrometers, etc) into a centralized Command and Data Handling unit (CDH). LION-PNP accomplishes this by inserting a Generic Sensor Interpreter (GSI) between the back-end of a device and the CDH. The GSI allows the CDH to automatically configure a sensor without requiring the user to manually install drivers. Furthermore, LION-PNP supports a number wireless networking protocols, allowing arrays of sensor nodes to be deployed rapidly over an area of interest. Finally, LION is compatible with the Android operating system, allowing the user to rapidly visualize, store and distribute data. In the following work, we report on the development of LION-PNP. To validate our hardware and software interfaces, we flew a small 4-point LION network on a multiple high altitude balloon launch. For this campaign, each node carried an array of sensors, including a magnetometer, temperature and pressure sensors, as well as GPS. The LION plug-and-play system allowed us to compose the network minutes before launch. Once in

  5. Climate and local abundance in freshwater fishes

    PubMed Central

    Knouft, Jason H.; Anthony, Melissa M.

    2016-01-01

    Identifying factors regulating variation in numbers of individuals among populations across a species' distribution is a fundamental goal in ecology. A common prediction, often referred to as the abundant-centre hypothesis, suggests that abundance is highest near the centre of a species' range. However, because of the primary focus on the geographical position of a population, this framework provides little insight into the environmental factors regulating local abundance. While range-wide variation in population abundance associated with environmental conditions has been investigated in terrestrial species, the relationship between climate and local abundance in freshwater taxa across species' distributions is not well understood. We used GIS-based temperature and precipitation data to determine the relationships between climatic conditions and range-wide variation in local abundance for 19 species of North American freshwater fishes. Climate predicted a portion of the variation in local abundance among populations for 18 species. In addition, the relationship between climatic conditions and local abundance varied among species, which is expected as lineages partition the environment across geographical space. The influence of local habitat quality on species persistence is well documented; however, our results also indicate the importance of climate in regulating population sizes across a species geographical range, even in aquatic taxa. PMID:27429769

  6. Climate and local abundance in freshwater fishes.

    PubMed

    Knouft, Jason H; Anthony, Melissa M

    2016-06-01

    Identifying factors regulating variation in numbers of individuals among populations across a species' distribution is a fundamental goal in ecology. A common prediction, often referred to as the abundant-centre hypothesis, suggests that abundance is highest near the centre of a species' range. However, because of the primary focus on the geographical position of a population, this framework provides little insight into the environmental factors regulating local abundance. While range-wide variation in population abundance associated with environmental conditions has been investigated in terrestrial species, the relationship between climate and local abundance in freshwater taxa across species' distributions is not well understood. We used GIS-based temperature and precipitation data to determine the relationships between climatic conditions and range-wide variation in local abundance for 19 species of North American freshwater fishes. Climate predicted a portion of the variation in local abundance among populations for 18 species. In addition, the relationship between climatic conditions and local abundance varied among species, which is expected as lineages partition the environment across geographical space. The influence of local habitat quality on species persistence is well documented; however, our results also indicate the importance of climate in regulating population sizes across a species geographical range, even in aquatic taxa.

  7. Lithosphere-to-Ionosphere Plug-and-Play Architecture (LION-PNP): Networking the Physical World Made Cheap and Easy

    NASA Astrophysics Data System (ADS)

    Darling, N. T.; Mendez, J. S.; Fritz, T. A.; Hoffman, C.

    2012-12-01

    The lack of rapidly reconfigurable and easily deployable instrumentation packages often results in information loss during unannounced or time-critical geophysical events such as spaceweather flare-ups, earthquakes, volcanic eruptions, and tsunamis. While increasingly powerful and sensitive sensor technologies have been created in the last years to study our planet, robust, yet simple and cost-effective, mechanical, electrical, and data interfaces between these devices and the user (scientist) have yet to be developed. Non-standardized interfaces make instrument integration and field operation cumbersome and error-prone. Indeed, the assembly and deployment of some systems can take months and incur high costs. To address this problem, we present the LIthosphere-to-IOnosphere Plug-aNd-Play architecture (LION-PNP), a complete, low cost integration protocol for space, atmospheric, and terrestrial sensor networks. Similar to the USB plug-and-play protocols created for personal computers, LION-PNP offers geophysicists and space scientists the ability to assemble and operate complex sensor packages by simply "plugging" devices (magnetometers, seismometers, GPS, spectrometers, etc) into a centralized Command and Data Handling unit (CDH). LION-PNP accomplishes this by inserting a Generic Sensor Interpreter (GSI) between the back-end of a device and the CDH. The GSI allows the CDH to automatically configure a sensor without requiring the user to manually install drivers. Mechanical integration is also accelerated by repackaging instruments according to the CubeSAT form-factor (multiples of 10 x 10 x 10 cm cubes). In the following work, we report on the development of LION-PNP. To demonstrate our initial success, we first discuss the Boston University Student-satellite for Applications and Training (BUSAT), a low-cost, modular, spaceweather satellite running LION-PNP. BUSAT is a completely student-driven project meant for magnetospheric-ionospheric research incorporating 4

  8. Effects of QCD bound states on dark matter relic abundance

    NASA Astrophysics Data System (ADS)

    Liew, Seng Pei; Luo, Feng

    2017-02-01

    We study scenarios where there exists an exotic massive particle charged under QCD in the early Universe. We calculate the formation and dissociation rates of bound states formed by pairs of these particles, and apply the results in dark matter (DM) coannihilation scenarios, including also the Sommerfeld effect. We find that on top of the Sommerfeld enhancement, bound-state effects can further significantly increase the largest possible DM masses which can give the observed DM relic abundance, by ˜ 30-100% with respect to values obtained by considering the Sommerfeld effect only, for the color triplet or octet exotic particles we consider. In particular, it indicates that the Bino DM mass in the right-handed stop-Bino coannihilation scenario in the Minimal Supersymmetric extension of the Standard Model (MSSM) can reach ˜ 2.5 TeV, even though the potential between the stop and antistop prior to forming a bound state is repulsive. We also apply the bound-state effects in the calculations of relic abundance of long-lived or metastable massive colored particles, and discuss the implications on the BBN constraints and the abundance of a super-weakly interacting DM. The corrections for the bound-state effect when the exotic massive colored particles also carry electric charges, and the collider bounds are also discussed.

  9. Abundances of the elements - Meteoritic and solar

    NASA Technical Reports Server (NTRS)

    Anders, Edward; Grevesse, Nicolas

    1989-01-01

    New abundance tables have been compiled for C1 chondrites and the solar photosphere and corona, based on a critical review of the literature to mid-1988. The meteorite data are generally accurate to + or - 5-10 percent. Significant discrepancies between the sun and meteorites occur only for Fe, Mn, Ge, Pb, and W; other well-determined elements agree to + or - 9 percent on the average. There is no evidence for group fractionations in C1 chondrites of cosmochemically similar elements (refractories, siderophiles, volatiles, etc.), but a selective fractionation of Fe cannot be ruled out. Abundances of odd-A nuclides between A = 65 and 209 show a generally smooth trend, with elemental abundances conforming to the slope defined by isotopic abundances. Significant irregularities occur in the Nd-Sm-Eu region, however, suggesting that the abundance curve is dependably smooth only down to about 20 percent level.

  10. Electric machine

    DOEpatents

    El-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Reddy, Patel Bhageerath [Madison, WI

    2012-07-17

    An interior permanent magnet electric machine is disclosed. The interior permanent magnet electric machine comprises a rotor comprising a plurality of radially placed magnets each having a proximal end and a distal end, wherein each magnet comprises a plurality of magnetic segments and at least one magnetic segment towards the distal end comprises a high resistivity magnetic material.

  11. Teaching Electricity.

    ERIC Educational Resources Information Center

    Iona, Mario

    1982-01-01

    To clarify the meaning of electrical terms, a chart is used to compare electrical concepts and relationships with a more easily visualized system in which water flows from a hilltop reservoir through a pipe to drive a mill at the bottom of the hill. A diagram accompanies the chart. (Author/SK)

  12. Influence of Coronal Abundance Variations

    NASA Technical Reports Server (NTRS)

    Scargle, Jeffrey D. (Technical Monitor); Kashyap, Vinay

    2005-01-01

    The PI of this project was Jeff Scargle of NASA/Ames. Co-I's were Alma Connors of Eureka Scientific/Wellesley, and myself. Part of the work was subcontracted to Eureka Scientific via SAO, with Vinay Kashyap as PI. This project was originally assigned grant number NCC2-1206, and was later changed to NCC2-1350 for administrative reasons. The goal of the project was to obtain, derive, and develop statistical and data analysis tools that would be of use in the analyses of high-resolution, high-sensitivity data that are becoming available with new instruments. This is envisioned as a cross-disciplinary effort with a number of "collaborators" including some at SA0 (Aneta Siemiginowska, Peter Freeman) and at the Harvard Statistics department (David van Dyk, Rostislav Protassov, Xiao-li Meng, Epaminondas Sourlas, et al). We have developed a new tool to reliably measure the metallicities of thermal plasma. It is unfeasible to obtain high-resolution grating spectra for most stars, and one must make the best possible determination based on lower-resolution, CCD-type spectra. It has been noticed that most analyses of such spectra have resulted in measured metallicities that were significantly lower than when compared with analyses of high- resolution grating data where available (see, e.g., Brickhouse et al., 2000, ApJ 530,387). Such results have led to the proposal of the existence of so-called Metal Abundance Deficient, or "MAD" stars (e.g., Drake, J.J., 1996, Cool Stars 9, ASP Conf.Ser. 109, 203). We however find that much of these analyses may be systematically underestimating the metallicities, and using a newly developed method to correctly treat the low-counts regime at the high-energy tail of the stellar spectra (van Dyk et al. 2001, ApJ 548,224), have found that the metallicities of these stars are generally comparable to their photospheric values. The results were reported at the AAS (Sourlas, Yu, van Dyk, Kashyap, and Drake, 2000, BAAS 196, v32, #54.02), and at the

  13. NREL Explores Earth-Abundant Materials for Future Solar Cells (Fact Sheet)

    SciTech Connect

    Not Available

    2012-10-01

    Researchers at the National Renewable Energy Laboratory (NREL) are using a theory-driven technique - sequential cation mutation - to understand the nature and limitations of promising solar cell materials that can replace today's technologies. Finding new materials that use Earth-abundant elements and are easily manufactured is important for large-scale solar electricity deployment.

  14. Modeling void abundance in modified gravity

    NASA Astrophysics Data System (ADS)

    Voivodic, Rodrigo; Lima, Marcos; Llinares, Claudio; Mota, David F.

    2017-01-01

    We use a spherical model and an extended excursion set formalism with drifting diffusive barriers to predict the abundance of cosmic voids in the context of general relativity as well as f (R ) and symmetron models of modified gravity. We detect spherical voids from a suite of N-body simulations of these gravity theories and compare the measured void abundance to theory predictions. We find that our model correctly describes the abundance of both dark matter and galaxy voids, providing a better fit than previous proposals in the literature based on static barriers. We use the simulation abundance results to fit for the abundance model free parameters as a function of modified gravity parameters, and show that counts of dark matter voids can provide interesting constraints on modified gravity. For galaxy voids, more closely related to optical observations, we find that constraining modified gravity from void abundance alone may be significantly more challenging. In the context of current and upcoming galaxy surveys, the combination of void and halo statistics including their abundances, profiles and correlations should be effective in distinguishing modified gravity models that display different screening mechanisms.

  15. Oxygen abundance maps of CALIFA galaxies

    NASA Astrophysics Data System (ADS)

    Zinchenko, I. A.; Pilyugin, L. S.; Grebel, E. K.; Sánchez, S. F.; Vílchez, J. M.

    2016-11-01

    We construct maps of the oxygen abundance distribution across the discs of 88 galaxies using Calar Alto Legacy Integral Field Area survey (CALIFA) Data Release 2 (DR2) spectra. The position of the centre of a galaxy (coordinates on the plate) was also taken from the CALIFA DR2. The galaxy inclination, the position angle of the major axis, and the optical radius were determined from the analysis of the surface brightnesses in the Sloan Digital Sky Survey (SDSS) g and r bands of the photometric maps of SDSS Data Release 9. We explore the global azimuthal abundance asymmetry in the discs of the CALIFA galaxies and the presence of a break in the radial oxygen abundance distribution. We found that there is no significant global azimuthal asymmetry for our sample of galaxies, i.e. the asymmetry is small, usually lower than 0.05 dex. The scatter in oxygen abundances around the abundance gradient has a comparable value, ≲0.05 dex. A significant (possibly dominant) fraction of the asymmetry can be attributed to the uncertainties in the geometrical parameters of these galaxies. There is evidence for a flattening of the radial abundance gradient in the central part of 18 galaxies. We also estimated the geometric parameters (coordinates of the centre, the galaxy inclination and the position angle of the major axis) of our galaxies from the analysis of the abundance map. The photometry-map-based and the abundance-map-based geometrical parameters are relatively close to each other for the majority of the galaxies but the discrepancy is large for a few galaxies with a flat radial abundance gradient.

  16. Abundance fluctuations in the interstellar medium

    NASA Technical Reports Server (NTRS)

    Jura, M.

    1982-01-01

    The determination of abundances within the interstellar medium is reviewed. It appears that interstellar abundances within 1 kpc of the Sun are uniform to within a factor of two or three, but it is not yet possible to determine whether there are real fluctuations at this level except for deuterium for which the factor of two variations appear to be real. Establishing the level of local fluctuations in the abundances is of considerable importance for understanding the history of nucleosynthesis in the solar neighborhood, the evolution of the interstellar medium and the formation of stars.

  17. Interstellar Abundances Toward X Per, Revisited

    NASA Technical Reports Server (NTRS)

    Valencic, Lynne A.; Smith, Randall K.

    2012-01-01

    The nearby X-ray binary X Per (HD 24534) provides a useful beacon with which to measure elemental abundances in the local ISM. We examine absorption features of O, Mg, and Si along this line of sight using spectra from the Chandra Observatory's LETG/ACIS-S and XMM-Newton's RGS instruments. In general, we find that the abundances and their ratios are similar to those of young F and G stars and the most recent solar values. We compare our results with abundances required by dust grain models.

  18. Interstellar Abundances Toward X Per, Revisited

    NASA Technical Reports Server (NTRS)

    Valencic, Lynne A.; Smith, Randall K.

    2014-01-01

    The nearby X-ray binary X Per (HD 24534) provides a useful beacon with which to measure elemental abundances in the local ISM. We examine absorption features of 0, Mg, and Si along this line of sight using spectra from the Chandra Observatory's LETG/ ACIS-S and XMM-Newton's RGS instruments. In general, we find that the abundances and their ratios are similar to those of young F and G stars and the most recent solar values. We compare our results with abundances required by dust grain models.

  19. Electrical connector

    DOEpatents

    Dilliner, Jennifer L.; Baker, Thomas M.; Akasam, Sivaprasad; Hoff, Brian D.

    2006-11-21

    An electrical connector includes a female component having one or more receptacles, a first test receptacle, and a second test receptacle. The electrical connector also includes a male component having one or more terminals configured to engage the one or more receptacles, a first test pin configured to engage the first test receptacle, and a second test pin configured to engage the second test receptacle. The first test receptacle is electrically connected to the second test receptacle, and at least one of the first test pin and the second test pin is shorter in length than the one or more terminals.

  20. Electrical Conductivity.

    ERIC Educational Resources Information Center

    Hershey, David R.; Sand, Susan

    1993-01-01

    Explains how electrical conductivity (EC) can be used to measure ion concentration in solutions. Describes instrumentation for the measurement, temperature dependence and EC, and the EC of common substances. (PR)

  1. Electrical Conductivity.

    ERIC Educational Resources Information Center

    Allen, Philip B.

    1979-01-01

    Examines Drude's classical (1900) theory of electrical conduction, details the objections to and successes of the 1900 theory, and investigates the Quantum (1928) theory of conduction, reviewing its successes and limitations. (BT)

  2. Abundances of Elements in Stellar Coronae

    NASA Technical Reports Server (NTRS)

    Drake, Jeremy

    1998-01-01

    Interest in stellar coronal abundances was piqued several years ago by the launch of satellites that were able to study the compositions of coronae on stars other than the sun. Motivated by the possibility that other stellar coronae might share the First Ionization Potential (FIP) Effect solar abundance anomaly, we have in recent years been attempting to determine coronal element abundances in other stars. I will review these results, together with similar results reported in the literature, from a critical perspective of understanding the true uncertainties involved in the measurements. The importance of element abundances for coronal physics will be highlighted, and it will be shown that the differences in the chemical compositions of active stars allow us to draw new conclusions regarding the nature of stellar coronae and coronal heating.

  3. The lithium abundance in extreme halo stars

    SciTech Connect

    Hobbs, L.M.; Thorburn, J.A. )

    1991-07-01

    New observations are reported of atmospheric Li abundances for six extremely metal-poor dwarfs with Fe-H ratios not higher than {minus}2.59 and T(e) not lower than 5950 K. The spectra were obtained in 1990 at Kitt Peak National Observatory, using the echelle spectrograph with the UV Fast camera. The resulting Li abundances for these stars range between N(Li) values of 1.99 and 2.24, where N(Li) = 12 + log (Li/H). These results agree with the abundances reported previously for five other metal-poor dwarfs with the Fe/H ratios not above {minus}2.60. The invariance of Li abundance in these 11 stars indicates a primordial origin for most of the Li observed in these Galactic stars. 23 refs.

  4. New historical records and relationships among 14C production rates, abundance and color of low latitude auroras and sunspot abundance

    NASA Astrophysics Data System (ADS)

    Abbott, Dallas; Juhl, Robert

    2016-12-01

    Incursions of high-energy particles from space, specifically solar energetic particles and galactic cosmic rays, have significant effects on the Earth, including disruption of the Earth's magnetic field, generation of electric fields strong enough to damage electronic devices as well as the production of auroras at low-latitudes, within 45° of the magnetic equator. We examine the relationships among 14C production, auroral abundance, auroral color and sunspot abundance using existing data supplemented by a new dataset. The new dataset, based on Chinese and Korean records from A.D. 1100-1700, includes 46 new or revised records of sunspots and 279 records of low-latitude auroras. Low-latitude auroras are predominantly red (66%, 835 events) with lesser proportions of white (20%, 253 events) and black auroras (6%, 67 events). All other auroral colors (green, yellow, multicolored, blue and purple) aggregate to a total of 100 events (8%). Overall, white auroras are more frequent during times of higher 14C production. We use two empirical methods of evaluating the flux of high-energy particles: modeled peaks and lows in 14C production and peaks and lows in the 14C calibration curve. We find that comparison to modeled 14C production gives significant results. White auroras are significantly more abundant (98% probability) at times of high production of 14C. Red auroras are somewhat more abundant (88% probability) at times of low production of 14C. The abundances of black, multicolored, green, yellow, and blue auroras between times of low and high 14C production are not significantly different. Violet/purple auroras are significantly more abundant (98% probability) at times of low 14C production. The positive correlation of violet/purple auroras with times of low14C production rate and the lack of correlation of blue auroras with times of high14C production is surprising, for this portion of the visible spectrum contains strong emission lines and some lines with high

  5. Coronae of Stars with Supersolar Elemental Abundances

    NASA Technical Reports Server (NTRS)

    Peretz, Uria; Behar, Ehud; Drake, Stephen A.

    2015-01-01

    Coronal elemental abundances are known to deviate from the photospheric values of their parent star, with the degree of deviation depending on the first ionization potential (FIP). This study focuses on the coronal composition of stars with supersolar photospheric abundances. We present the coronal abundances of six such stars: 11 LMi, iota Hor, HR 7291, tau Boo, and alpha Cen A and B. These stars all have high-statistics X-ray spectra, three of which are presented for the first time. The abundances we measured were obtained using the line-resolved spectra of the Reflection Grating Spectrometer (RGS) in conjunction with the higher throughput EPIC-pn camera spectra onboard the XMM-Newton observatory. A collisionally ionized plasma model with two or three temperature components is found to represent the spectra well. All elements are found to be consistently depleted in the coronae compared to their respective photospheres. For 11 LMi and tau Boo no FIP effect is present, while iota Hor, HR 7291, and alpha Cen A and B show a clear FIP trend. These conclusions hold whether the comparison is made with solar abundances or the individual stellar abundances. Unlike the solar corona, where low-FIP elements are enriched, in these stars the FIP effect is consistently due to a depletion of high-FIP elements with respect to actual photospheric abundances. A comparison with solar (instead of stellar) abundances yields the same fractionation trend as on the Sun. In both cases, a similar FIP bias is inferred, but different fractionation mechanisms need to be invoked.

  6. Electric generator

    DOEpatents

    Foster, Jr., John S.; Wilson, James R.; McDonald, Jr., Charles A.

    1983-01-01

    1. In an electrical energy generator, the combination comprising a first elongated annular electrical current conductor having at least one bare surface extending longitudinally and facing radially inwards therein, a second elongated annular electrical current conductor disposed coaxially within said first conductor and having an outer bare surface area extending longitudinally and facing said bare surface of said first conductor, the contiguous coaxial areas of said first and second conductors defining an inductive element, means for applying an electrical current to at least one of said conductors for generating a magnetic field encompassing said inductive element, and explosive charge means disposed concentrically with respect to said conductors including at least the area of said inductive element, said explosive charge means including means disposed to initiate an explosive wave front in said explosive advancing longitudinally along said inductive element, said wave front being effective to progressively deform at least one of said conductors to bring said bare surfaces thereof into electrically conductive contact to progressively reduce the inductance of the inductive element defined by said conductors and transferring explosive energy to said magnetic field effective to generate an electrical potential between undeformed portions of said conductors ahead of said explosive wave front.

  7. Modeling abundance effects in distance sampling

    USGS Publications Warehouse

    Royle, J. Andrew; Dawson, D.K.; Bates, S.

    2004-01-01

    Distance-sampling methods are commonly used in studies of animal populations to estimate population density. A common objective of such studies is to evaluate the relationship between abundance or density and covariates that describe animal habitat or other environmental influences. However, little attention has been focused on methods of modeling abundance covariate effects in conventional distance-sampling models. In this paper we propose a distance-sampling model that accommodates covariate effects on abundance. The model is based on specification of the distance-sampling likelihood at the level of the sample unit in terms of local abundance (for each sampling unit). This model is augmented with a Poisson regression model for local abundance that is parameterized in terms of available covariates. Maximum-likelihood estimation of detection and density parameters is based on the integrated likelihood, wherein local abundance is removed from the likelihood by integration. We provide an example using avian point-transect data of Ovenbirds (Seiurus aurocapillus) collected using a distance-sampling protocol and two measures of habitat structure (understory cover and basal area of overstory trees). The model yields a sensible description (positive effect of understory cover, negative effect on basal area) of the relationship between habitat and Ovenbird density that can be used to evaluate the effects of habitat management on Ovenbird populations.

  8. TEA: A Code Calculating Thermochemical Equilibrium Abundances

    NASA Astrophysics Data System (ADS)

    Blecic, Jasmina; Harrington, Joseph; Bowman, M. Oliver

    2016-07-01

    We present an open-source Thermochemical Equilibrium Abundances (TEA) code that calculates the abundances of gaseous molecular species. The code is based on the methodology of White et al. and Eriksson. It applies Gibbs free-energy minimization using an iterative, Lagrangian optimization scheme. Given elemental abundances, TEA calculates molecular abundances for a particular temperature and pressure or a list of temperature-pressure pairs. We tested the code against the method of Burrows & Sharp, the free thermochemical equilibrium code Chemical Equilibrium with Applications (CEA), and the example given by Burrows & Sharp. Using their thermodynamic data, TEA reproduces their final abundances, but with higher precision. We also applied the TEA abundance calculations to models of several hot-Jupiter exoplanets, producing expected results. TEA is written in Python in a modular format. There is a start guide, a user manual, and a code document in addition to this theory paper. TEA is available under a reproducible-research, open-source license via https://github.com/dzesmin/TEA.

  9. Report on carbon and nitrogen abundance studies

    NASA Technical Reports Server (NTRS)

    Boehm-Vitense, Erika

    1991-01-01

    The aim of the proposal was to determine the nitrogen to carbon abundance ratios from transition layer lines in stars with different T(sub eff) and luminosities. The equations which give the surface emission line fluxes and the measured ratio of the NV to CIV emission line fluxes are presented and explained. The abundance results are compared with those of photospheric abundance studies for stars in common with the photospheric investigations. The results show that the analyses are at least as accurate as the photospheric determinations. These studies can be extended to F and early G stars for which photospheric abundance determinations for giants are hard to do because molecular bands become too weak. The abundance determination in the context of stellar evolution is addressed. The N/C abundance ratio increases steeply at the point of evolution for which the convection zone reaches deepest. Looking at the evolution of the rotation velocities v sin i, a steep decrease in v sin i is related to the increasing depth of the convection zone. It is concluded that the decrease in v sin i for T(sub eff) less than or approximately = 5800 K is most probably due to the rearrangement of the angular momentum in the stars due to deep convective mixing. It appears that the convection zone is rotating with nearly depth independent angular momentum. Other research results and ongoing projects are discussed.

  10. Solar Models with New Low Metal Abundances

    NASA Astrophysics Data System (ADS)

    Yang, Wuming

    2016-04-01

    In the past decade, the photospheric abundances of the Sun had been revised several times by many observers. The standard solar models constructed with the new low-metal abundances disagree with helioseismic results and detected neutrino fluxes. The solar model problem has puzzled some stellar physicists for more than 10 years. Rotation, enhanced diffusion, convection overshoot, and magnetic fields are used to reconcile the new abundances with helioseismology. The too low helium subsurface abundance in enhanced diffusion models can be improved by the mixing caused by rotation and magnetic fields. The problem of the depth of the convective zone in rotating models can be resolved by convection overshoot. Consequently, the Asplund-Grevesse-Sauval rotation model including overshooting (AGSR) reproduces the seismically inferred sound-speed and density profiles and the convection zone depth as well as the Grevesse & Sauval model computed before. But this model fails to reproduce the surface helium abundance, which is 0.2393 (2.6σ away from the seismic value), and neutrino fluxes. The magnetic model called AGSM keeps the agreement of the AGSR and improves the prediction of the surface helium abundance. The observed separation ratios r02 and r13 are reasonably reproduced by AGSM. Moreover, neutrino fluxes calculated by this model are not far from the detected neutrino fluxes and the predictions of previous works.

  11. A cheap and non-destructive approach to increase coverage/loading of hydrophilic hydroxide on hydrophobic carbon for lightweight and high-performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Zhang, Liuyang; Gong, Hao

    2015-12-01

    Carbon-based substrates offer unprecedented advantages in lightweight supercapacitors. However, it is still challenging to achieve high coverage or loading. Different from the traditional belief that a lack of defects or functional groups is the cause of poor growth on carbon-based substrates, we reckon that the major cause is the discrepancy between the hydrophilic nature of the metal oxide/hydroxide and the hydrophobic nature of carbon. To solve this incompatibility, we introduced ethanol into the precursor solution. The method to synthesize nickel copper hydroxide on carbon fiber paper employs only water and ethanol, in addition to nickel acetate and copper acetate. The results revealed good growth and tight adhesion of active materials on carbon fiber paper substrates. The specific capacitance and energy density per total weight of the active material plus substrate (carbon fiber paper, current collector) reached 770 F g-1 and 33 Wh kg-1 (1798 F g-1 and 54 Wh kg-1 per weight of the active materials), owing to the high loading of active material and the light weight of carbon fiber paper. These results signified the achievability of light, cheap and high-performance supercapacitors by an environmental-friendly approach.

  12. Living in a 'fat swamp': exposure to multiple sources of accessible, cheap, energy-dense fast foods in a deprived community.

    PubMed

    Saunders, Patrick; Saunders, Annie; Middleton, John

    2015-06-14

    This study assesses the levels of fats, including trans-fatty acids, and salt in common takeaway fast foods in a deprived urban municipality in the West Midlands, England, and implications in the context of the spatial distribution of fast food takeaways. The results of the compositional analysis of over 250 take-out foods were compared with established and derived standards. About 70% of products exceeded the recommendation that a meal should contain less than 30% of a Guideline Daily Amount (GDA). More than half of them exceeded 50% GDA for at least one metric, including 81% of all analyses for SFA. And 17% of samples exceeded the GDA for SFA, including each of two meals that contained about twice the GDA. Over 30% samples exceeded the children's GDA for total fat or SFA. 27% of salt analyses exceeded the GDA. People in Sandwell are exposed to large portion sizes and high levels of fats and salt in takeaway foods, with levels in some foods having increased since 2010. Given this population's limited options to break out of a highly compromising environment of living simultaneously in a 'swamp' of unhealthy, readily accessible and cheap takeaways, and a 'desert' of healthy options, an immediate and innovative package of interventions is required.

  13. New analytical method for the determination of musks in personal care products by Quick, Easy, Cheap, Effective, Rugged, and Safe extraction followed by GC-MS.

    PubMed

    Homem, Vera; Silva, José Avelino; Cunha, Carina; Alves, Arminda; Santos, Lúcia

    2013-07-01

    Synthetic musks are organic compounds used as fragrance additives and fixative compounds in a diversity of personal care products. A new method based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction followed by GC-MS for the analysis of 12 musks in personal care products was developed and validated. Some experimental parameters, such as total QuEChERS mass, sample mass/solvent volume ratio, type of extraction solvent, as well as salts and sorbents amount were investigated and optimized. The final method involves the musks extraction using acetonitrile, followed by the addition of anhydrous magnesium sulphate and sodium acetate. The clean-up step was performed using dispersive SPE with primary and secondary amine and octadecyl-silica sorbents. This extraction procedure is fast (about 10 min) when compared to other traditional approaches. The method was robust for the matrices studied and shows a high precision (%RSD < 15%) and accuracy (average recovery of 85%), allowing the detection of musks in minimum concentrations between 0.01 ng/g (galaxolide) and 15.80 ng/g (musk xylene). The developed method was applied to the analysis of 12 samples, which revealed musks concentrations ranging from 2 ng/g (toothpaste) to 882,340 ng/g (perfumed body lotion).

  14. Simultaneous determination of carbamate insecticides and mycotoxins in cereals by reversed phase liquid chromatography tandem mass spectrometry using a quick, easy, cheap, effective, rugged and safe extraction procedure.

    PubMed

    Zhang, Jin-Ming; Wu, Yin-Liang; Lu, Yao-Bin

    2013-02-01

    A simple, sensitive and reliable analytical method was developed for the simultaneous determination of 22 carbamate insecticides and 17 mycotoxins in cereals by ultra high performance liquid chromatography electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Carbamates and mycotoxins were extracted from cereal samples using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) procedure without any further clean-up step. The extract was diluted with water containing 0.1% formic acid and 5.0mM ammonium acetate, and analyzed by LC-MS/MS on a Waters Acquity BEH C(18) column with water (0.1% formic acid, 0.50mM ammonium acetate)/methanol as mobile phase with gradient elution. Matrix-matched calibration was used for quantification. Blank samples (rice, wheat and corn) were fortified at 5, 10 and 50 μg/kg except for five zearalenonic compounds at 25, 50 and 250 μg/kg, and recoveries were in the range of 70-120%. Relative standard deviations were lower than 20% in all cases. The LOQ values were in the range of 0.20-29.7 μg/kg. The method is suitable for the simultaneous determination of carbamate insecticides and mycotoxins in cereals. The total time required for the analysis of one sample, including sample preparation, was about 35 min.

  15. Determination of polycyclic aromatic hydrocarbon metabolites in milk by a quick, easy, cheap, effective, rugged and safe extraction and capillary electrophoresis.

    PubMed

    Knobel, Gaston; Campiglia, Andres D

    2013-07-01

    We describe the first application of a quick, easy, cheap, effective, rugged and safe extraction technique to the CZE analysis of monohydroxylated metabolites of polycyclic aromatic hydrocarbons in milk. Complete resolution of 2-hydroxyfluorenene, 1-hydroxynaphthalene, 2-hydroxynaphthalene, 3-hydroxyphenanthrene, and 9-hydroxyphenanthrene was accomplished in 4 min of electrophoretic run. Limits of detection at the parts-per-billion were obtained with a single solvent (acetonitrile) for metabolite extraction and sample stacking. The small sample volume (1.2 mL) and the conservative usage of chemicals provided a simple and rapid procedure for the simultaneous extraction of numerous samples. Adding 4 min of electrophoretic run per sample, it should be possible to screen ten samples in approximately 1 h of analysis time. The nanoliter extract volume required for sample injection allows for further chromatographic usage and confirmation of positive samples. The unique electrophoretic pattern of the studied metabolites demonstrates the potential for the unambiguous determination of positional isomers with very similar chromatographic behaviors and undistinguishable mass fragmentation patterns.

  16. Food Byproducts as a New and Cheap Source of Bioactive Compounds: Lignans with Antioxidant and Anti-inflammatory Properties from Crataegus pinnatifida Seeds.

    PubMed

    Huang, Xiao-Xiao; Bai, Ming; Zhou, Le; Lou, Li-Li; Liu, Qing-Bo; Zhang, Yan; Li, Ling-Zhi; Song, Shao-Jiang

    2015-08-19

    During the process of manufacturing hawthorn (Crataegus pinnatifida) juice and jam, a significant quantity of byproducts (leaves, seeds) is generated. The antioxidant and anti-inflammatory bioassay-guided fractionation of the extract of hawthorn seeds has led to the isolation of eight new lignans, hawthornnins A-H (1-8), and seven known analogues (9-15). Their structures were elucidated by spectroscopic techniques, including 1D and 2D NMR and CD spectra. The radical-scavenging effects of all isolated compounds were investigated. 1-6 and 8 showed moderate activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), whereas 1-6 and 14 displayed good 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical-scavenging activities that were even more potent than that of trolox. In addition, all isolates were evaluated for their anti-inflammatory activities by detecting the nitric oxide (NO) and tumor necrosis factor α (TNF-α) production by the LPS-induced murine macrophage cell line RAW264.7, and compounds 1-7, 13, and 14 exhibited potent inhibition of NO and TNF-α production. The structure-activity relationships of isolated lignans were also examined, and the results obtained show that C. pinnatifida seeds can be regarded as a potential new and cheap source of antioxidants and inflammation inhibitors.

  17. A cheap and non-destructive approach to increase coverage/loading of hydrophilic hydroxide on hydrophobic carbon for lightweight and high-performance supercapacitors

    PubMed Central

    Zhang, Liuyang; Gong, Hao

    2015-01-01

    Carbon-based substrates offer unprecedented advantages in lightweight supercapacitors. However, it is still challenging to achieve high coverage or loading. Different from the traditional belief that a lack of defects or functional groups is the cause of poor growth on carbon-based substrates, we reckon that the major cause is the discrepancy between the hydrophilic nature of the metal oxide/hydroxide and the hydrophobic nature of carbon. To solve this incompatibility, we introduced ethanol into the precursor solution. The method to synthesize nickel copper hydroxide on carbon fiber paper employs only water and ethanol, in addition to nickel acetate and copper acetate. The results revealed good growth and tight adhesion of active materials on carbon fiber paper substrates. The specific capacitance and energy density per total weight of the active material plus substrate (carbon fiber paper, current collector) reached 770 F g−1 and 33 Wh kg−1 (1798 F g−1 and 54 Wh kg−1 per weight of the active materials), owing to the high loading of active material and the light weight of carbon fiber paper. These results signified the achievability of light, cheap and high-performance supercapacitors by an environmental-friendly approach. PMID:26643665

  18. Development of a cheap and accessible carbon fibers-in-poly(ether ether ketone) tube with high stability for online in-tube solid-phase microextraction.

    PubMed

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2016-02-01

    Carbon fibers (CFs) are one kind of important industrial materials that can be obtained commercially at low price. Based on the high extraction efficiency of carbon sorbents, a cheap and accessible carbon fibers-in-poly(ether ether ketone) (PEEK) tube was developed for online in-tube solid-phase microextraction (SPME) method. Coupled to high performance liquid chromatography (HPLC), the CFs-in-tube SPME was applied to analyze eight polycyclic aromatic hydrocarbons (PAHs) in environmental aqueous samples. Extraction conditions (sampling rate, extraction time, methanol content) and desorption time were investigated for optimization of conditions. Under the optimum conditions, the CFs-in-tube SPME-HPLC method provided high extraction efficiency with enrichment factors up to 1748. Good linearity (0.05-50 μg L(-1), 0.5-50 μg L(-1)) and low detection limits (0.01-0.1 μg L(-1)) were also obtained. The online analysis method was finally applied to determine several model PAHs analytes in real environmental aqueous samples. Some target analytes were detected and relative recoveries were in the range of 92.3-111%. Due to natural chemical stability of carbon fibers and PEEK tube, the CFs-in-tube device exhibited high resistance to organic solvent, acid and alkaline conditions.

  19. Magnetic "one-step" quick, easy, cheap, effective, rugged and safe method for the fast determination of pesticide residues in freshly squeezed juice.

    PubMed

    Zheng, Hao-Bo; Ding, Jun; Zheng, Shu-Jian; Yu, Qiong-Wei; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-06-12

    A "one-step" quick, easy, cheap, effective, rugged and safe (QuEChERS) method was proposed for pesticide residue analysis in freshly squeezed juice of fruits and vegetables. In this method, a new magnetic adsorbent prepared by simple physical blending was adopt, which could endow the sample mixture with magnetic separability. To achieve the best performance of the modified QuEChERS towards target analytes, the amounts of adsorbents were investigated. Under the optimized conditions, a simple, rapid and sensitive method for the determination of 11 pesticide residues in freshly squeezed juice was established by coupling modified QuEChERS to gas chromatography/mass spectrometry analysis. The limits of quantification of the proposed method for 11 pesticides ranged from 2.0 to 49.6ng/g. Good linearities (R value ≥0.9993) were achieved at different concentration ranges, and acceptable method reproducibility was obtained by evaluating intra- and inter-day precisions with the relative standard deviations being less than 8.5% and 13.5%, respectively. The recoveries were in the range of 70.3-114.1% at different concentrations for real samples. Compared with the traditional QuEChERS methods, extraction/partitioning and purification were integrated into one step in the proposed method, which thus was time-saving (within 3.5min) with keeping good clean-up performance.

  20. Quick, easy, cheap, effective, rugged and safe method with magnetic graphitized carbon black and primary secondary amine as adsorbent and its application in pesticide residue analysis.

    PubMed

    Zheng, Hao-Bo; Zhao, Qin; Mo, Jie-Zhen; Huang, Yun-Qing; Luo, Yan-Bo; Yu, Qiong-Wei; Feng, Yu-Qi

    2013-07-26

    By using magnetic graphitized carbon black and primary secondary amine (GCB/PSA/MNPs) as adsorbent, a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method was proposed for pesticide residue analysis in vegetables. The magnetic adsorbent was fabricated via simple co-mixing method based on an "aggregate warp" mechanism. To achieve the optimum conditions of modified QuEChERS toward target analytes, several parameters, including the composition of analyte protectants and the amount of the adsorbents were investigated. Under the optimized conditions, a simple, rapid and effective method for the determination of 10 pesticide residues in vegetables was established by coupling modified QuEChERS to gas chromatography/mass spectrometry analysis. The detection limits of the proposed method for 10 pesticides ranged from 0.39 to 8.6ng/g. Good linearity (R value≥0.990) was achieved at concentration levels of 10-200ng/g, and acceptable method reproducibility was found as intra- and inter-day precisions, yielding the relative standard deviations less than 10.7% and 13.4%, respectively. The recoveries were in the range of 69.9-125.0% at different concentrations for real samples. Compared with the reported methods for the determination of a large number of samples, the proposed method has the advantage of less time-consuming in clean-up procedure.

  1. Magnetic graphene as modified quick, easy, cheap, effective, rugged and safe adsorbent for the determination of organochlorine pesticide residues in tobacco.

    PubMed

    Luo, Yan-Bo; Li, Xue; Jiang, Xing-Yi; Cai, Bao-Dong; Zhu, Feng-Peng; Zhang, Hong-Fei; Chen, Zai-Gen; Pang, Yong-Qiang; Feng, Yu-Qi

    2015-08-07

    In this study, magnetic graphene was used as modified quick, easy, cheap, effective, rugged and safe (QuEChERS) adsorbent for the determination of organochlorine pesticide (OCPs) residues in tobacco. To achieve the optimum conditions of modified QuEChERS procedure toward target analytes, several parameters affecting the clean-up efficiency including the amount of the adsorbent and clean-up time were investigated. Under the optimized conditions, a method for the determination of 26 OCPs residues in tobacco was established by coupling the modified QuEChERS procedure to on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry (on-line GPC-GC-MS(2)). The limits of detection of proposed method for 26 OCPs residues ranged from 0.01275 to 3.150ng/g. And good linearities of the proposed method were obtained with coefficients of determination (R(2)) greater than 0.9985 for all target analytes. Good reproducibility of method was obtained as intra- and inter-day precisions, the relative standard deviations were less than 11.1 and 15.0%, respectively. The apparent recoveries were in the range of 64-126% at different concentrations for real samples. Compared with the reported methods for the determination of OCPs residues in tobacco, the proposed method has the advantages of simple to operate, low cost and high clean-up ability. Finally, the method was successfully applied to the analysis of OCPs residues in real samples.

  2. Determination of multiple pesticides in fruits and vegetables using a modified quick, easy, cheap, effective, rugged and safe method with magnetic nanoparticles and gas chromatography tandem mass spectrometry.

    PubMed

    Li, Yan-Fei; Qiao, Lu-Qin; Li, Fang-Wei; Ding, Yi; Yang, Zi-Jun; Wang, Ming-Lin

    2014-09-26

    Based on a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) sample preparation method with Fe3O4 magnetic nanoparticles (MNPs) as the adsorbing material and gas chromatography-tandem mass spectrometry (GC-MS/MS) determination in multiple reaction monitoring (MRM) mode, we established a new method for the determination of multiple pesticides in vegetables and fruits. It was determined that bare MNPs have excellent function as adsorbent when purified, and it is better to be separated from the extract. The amount of MNPs influenced the clean-up performance and recoveries. To achieve the optimum performance of modified QuEChERS towards the target analytes, several parameters including the amount of the adsorbents and purification time were investigated. Under the optimum conditions, recoveries were evaluated in four representative matrices (tomato, cucumber, orange and apple) with the spiked concentrations of 10 μg kg(-1), 50 μg kg(-1)and 200 μg kg(-1) in all cases. The results showed that the recovery of 101 pesticides ranged between 71.5 and 111.7%, and the relative standard deviation was less than 10.5%. The optimum clean-up system improved the purification efficiency and simultaneously obtained satisfactory recoveries of multiple pesticides, including planar-ring pesticides. In short, the modified QuEChERS method in addition to MNPs used for removing impurities improved the speed of sample pre-treatment and exhibited an enhanced performance and purifying effect.

  3. A quick, easy, cheap, effective, rugged, and safe sample pretreatment and liquid chromatography with tandem mass spectrometry method for the simultaneous quantification of 33 mycotoxins in Lentinula edodes.

    PubMed

    Han, Zheng; Feng, Zhihong; Shi, Wen; Zhao, Zhihui; Wu, Yongjiang; Wu, Aibo

    2014-08-01

    Lentinula edodes, one of the most cultivated edible fungi in the world, are usually neglected for mycotoxins contamination due to the initial thinking of its resistance to mycotoxingenic molds. In the present study, a sensitive and reliable liquid chromatography with tandem mass spectrometry method was developed for the simultaneous quantification of 33 mycotoxins in L. edodes. Targeted mycotoxins were extracted using a quick, easy, cheap, effective, rugged, and safe procedure without any further clean-up step, and analyzed by liquid chromatography with tandem mass spectrometry on an Agilent Poroshell 120 EC-C18 column (100 × 3 mm, 2.7 μm) with a linear gradient elution program using water containing 5 mM ammonium acetate and methanol as the mobile phase. After validation by determining linearity (R(2) > 0.99), sensitivity (LOQ ≤ 20 ng/kg), recovery (73.6-117.9%), and precision (0.8-19.5%), the established method has been successfully applied to reveal the contamination states of various mycotoxins in L. edodes. Among the 30 tested samples, 22 were contaminated by various mycotoxins with the concentration levels ranging from 3.3-28,850.7 μg/kg, predicting that the edible fungus could be infected by the mycotoxins-producing fungi. To the best of our knowledge, this is the first report about real mycotoxins contamination in L. edodes.

  4. The elemental abundances in interplanetary dust particles

    NASA Astrophysics Data System (ADS)

    Arndt, Peter; Bohsung, Jörg; Maetz, Mischa; Jessberger, Elmar K.

    1996-11-01

    We compiled a table of all major, minor, and trace-element abundances in 89 interplanetary dust particles (IDPs) that includes data obtained with proton-induced x-ray emission (PIXE), synchroton x-ray fluorescence (SXRF), and secondary ion mass spectrometry (SIMS). For the first time, the reliability of the trace-element abundances in IDPs is tested by various crosschecks. We also report on the results of cluster analyses that we performed on IDP compositions. Because of the incompleteness of the data set, we included only the elements Cr, Mn, Ni, Cu, and Zn, normalized to Fe and CI chondrite abundances, that are determined in 73 IDPs. The data arrange themselves in four rather poorly defined groups that we discuss in relation to CI chondrites following the assumption that on the average CI abundances are most probable. The largest group (chondritic), with 44 members, has close to CI abundances for many refractory and moderately refractory elements (Na, Al, Si, P, K, Sc, Ti, V, Cr, Co, Ge, Sr). It is slightly depleted in Fe and more in Ca and S, while the volatile elements (Cl, Cu, Zn, Ga, Se, Rb) are enriched by =1.7 × CI and Br by 21 × CI. The low-Zn group, with 12 members, is very similar to the chondritic group except for its Zn-depletion, stronger Ca-depletion and Fe-enrichment. The low-Ni group, with 11 members, has Ni/Fe = 0.03 × CI and almost CI-like Ca, but its extraterrestrial origin is not established. The last group (6 members) contains non-systematic particles of unknown origin. We found that Fe is inhomogeneously distributed on a micron scale. Furthermore, the abundances of elements that are measured near their limits of detection are easily overestimated. These biases involved, the incomplete data set and possible contaminating processes prevent us from obtaining information on the specific origin(s) of IDPs from elemental abundances.

  5. Clonal growth and plant species abundance

    PubMed Central

    Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

    2014-01-01

    Background and Aims Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf–height–seed) traits and by actual performance in the botanical garden. Methods Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area – height – seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. Key Results After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Conclusions Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially

  6. Paper Thermoelectrics: Merging Nanotechnology with Naturally Abundant Fibrous Material.

    PubMed

    Sun, Chengjun; Goharpey, Amir Hossein; Rai, Ayush; Zhang, Teng; Ko, Dong-Kyun

    2016-08-31

    The development of paper-based sensors, antennas, and energy-harvesting devices can transform the way electronic devices are manufactured and used. Herein we describe an approach to fabricate paper thermoelectric generators for the first time by directly impregnating naturally abundant cellulose materials with p- or n-type colloidal semiconductor quantum dots. We investigate Seebeck coefficients and electrical conductivities as a function of temperature between 300 and 400 K as well as in-plane thermal conductivities using Angstrom's method. We further demonstrate equipment-free fabrication of flexible thermoelectric modules using p- and n-type paper strips. Leveraged by paper's inherently low thermal conductivity and high flexibility, these paper modules have the potential to efficiently utilize heat available in natural and man-made environments by maximizing the thermal contact to heat sources of arbitrary geometry.

  7. Electrically powered hand tool

    DOEpatents

    Myers, Kurt S.; Reed, Teddy R.

    2007-01-16

    An electrically powered hand tool is described and which includes a three phase electrical motor having a plurality of poles; an electrical motor drive electrically coupled with the three phase electrical motor; and a source of electrical power which is converted to greater than about 208 volts three-phase and which is electrically coupled with the electrical motor drive.

  8. Abundances in Eight M31 Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Hensley, Kerry G.; Kwitter, Karen B.; Corradi, Romano; Galera-Rosillo, R.; Balick, Bruce; Henry, Richard B. C.

    2014-06-01

    As part of a continuing project using planetary nebulae (PNe) to study the chemical evolution and formation history of M31 (see accompanying poster by Balick et al.), we obtained spectra of eight PNe in the fall of 2013 with the OSIRIS spectrograph on the GTC. All of these PNe are located outside M31’s inner disk and bulge. Spectral coverage extended from 3700-7800Å with a resolution of ~6 Å. Especially important in abundance determinations is the detection of the weak, temperature-sensitive auroral line of [O III], at 4363Å, which is often contaminated by Hg I 4358Å from streetlights; the remoteness of the GTC eliminated this difficulty. We reduced and measured the spectra using IRAF, and derived nebular diagnostics and abundances with ELSA, our in-house five-level-atom program. Here we report the chemical abundances determined from these spectra. The bottom line is that the oxygen abundances in these PNe are all within a factor of 2-3 of the solar value, (as are all the other M31 PNe our team has previously measured) despite the significant range of galactocentric distance. Future work will use these abundances to constrain models of the central star to estimate progenitor masses and ages. In particular we will use the results to investigate the hypothesis that these PNe might represent a population related to the encounter between M31 and M33 ~3 Gy ago. We gratefully acknowledge support from Williams College.

  9. Why is Trichodesmium abundant in the Kuroshio?

    NASA Astrophysics Data System (ADS)

    Shiozaki, T.; Takeda, S.; Itoh, S.; Kodama, T.; Liu, X.; Hashihama, F.; Furuya, K.

    2015-12-01

    The genus Trichodesmium is recognized as an abundant and major diazotroph in the Kuroshio, but the reason for this remains unclear. The present study investigated the abundance of Trichodesmium spp. and nitrogen fixation together with concentrations of dissolved iron and phosphate in the Kuroshio and its marginal seas. We performed the observations near the Miyako Islands, which form part of the Ryukyu Islands, situated along the Kuroshio, since our satellite analysis suggested that material transport could occur from the islands to the Kuroshio. Trichodesmium spp. bloomed (> 20 000 filaments L-1) near the Miyako Islands, abundance was high in the Kuroshio and the Kuroshio bifurcation region of the East China Sea, but was low in the Philippine Sea. The abundance of Trichodesmium spp. was significantly correlated with the total nitrogen fixation activity. The surface concentrations of dissolved iron (0.19-0.89 nM) and phosphate (< 3-36 nM) were similar for all of the study areas, indicating that the nutrient distribution could not explain the spatial differences in Trichodesmium spp. abundance and nitrogen fixation. Numerical particle-tracking experiments simulated the transportation of water around the Ryukyu Islands to the Kuroshio. Our results indicate that Trichodesmium growing around the Ryukyu Islands could be advected into the Kuroshio.

  10. REVIEW: Can habitat selection predict abundance?

    PubMed

    Boyce, Mark S; Johnson, Chris J; Merrill, Evelyn H; Nielsen, Scott E; Solberg, Erling J; van Moorter, Bram

    2016-01-01

    Habitats have substantial influence on the distribution and abundance of animals. Animals' selective movement yields their habitat use. Animals generally are more abundant in habitats that are selected most strongly. Models of habitat selection can be used to distribute animals on the landscape or their distribution can be modelled based on data of habitat use, occupancy, intensity of use or counts of animals. When the population is at carrying capacity or in an ideal-free distribution, habitat selection and related metrics of habitat use can be used to estimate abundance. If the population is not at equilibrium, models have the flexibility to incorporate density into models of habitat selection; but abundance might be influenced by factors influencing fitness that are not directly related to habitat thereby compromising the use of habitat-based models for predicting population size. Scale and domain of the sampling frame, both in time and space, are crucial considerations limiting application of these models. Ultimately, identifying reliable models for predicting abundance from habitat data requires an understanding of the mechanisms underlying population regulation and limitation.

  11. Hierarchical models of animal abundance and occurrence

    USGS Publications Warehouse

    Royle, J. Andrew; Dorazio, R.M.

    2006-01-01

    Much of animal ecology is devoted to studies of abundance and occurrence of species, based on surveys of spatially referenced sample units. These surveys frequently yield sparse counts that are contaminated by imperfect detection, making direct inference about abundance or occurrence based on observational data infeasible. This article describes a flexible hierarchical modeling framework for estimation and inference about animal abundance and occurrence from survey data that are subject to imperfect detection. Within this framework, we specify models of abundance and detectability of animals at the level of the local populations defined by the sample units. Information at the level of the local population is aggregated by specifying models that describe variation in abundance and detection among sites. We describe likelihood-based and Bayesian methods for estimation and inference under the resulting hierarchical model. We provide two examples of the application of hierarchical models to animal survey data, the first based on removal counts of stream fish and the second based on avian quadrat counts. For both examples, we provide a Bayesian analysis of the models using the software WinBUGS.

  12. Abundance of sea kraits correlates with precipitation.

    PubMed

    Lillywhite, Harvey B; Tu, Ming-Chung

    2011-01-01

    Recent studies have shown that sea kraits (Laticauda spp.)--amphibious sea snakes--dehydrate without a source of fresh water, drink only fresh water or very dilute brackish water, and have a spatial distribution of abundance that correlates with freshwater sites in Taiwan. The spatial distribution correlates with sites where there is a source of fresh water in addition to local precipitation. Here we report six years of longitudinal data on the abundance of sea kraits related to precipitation at sites where these snakes are normally abundant in the coastal waters of Lanyu (Orchid Island), Taiwan. The number of observed sea kraits varies from year-to-year and correlates positively with previous 6-mo cumulative rainfall, which serves as an inverse index of drought. Grouped data for snake counts indicate that mean abundance in wet years is nearly 3-fold greater than in dry years, and this difference is significant. These data corroborate previous findings and suggest that freshwater dependence influences the abundance or activity of sea kraits on both spatial and temporal scales. The increasing evidence for freshwater dependence in these and other marine species have important implications for the possible impact of climate change on sea snake distributions.

  13. RELATIVE ABUNDANCE MEASUREMENTS IN PLUMES AND INTERPLUMES

    SciTech Connect

    Guennou, C.; Hahn, M.; Savin, D. W.

    2015-07-10

    We present measurements of relative elemental abundances in plumes and interplumes. Plumes are bright, narrow structures in coronal holes that extend along open magnetic field lines far out into the corona. Previous work has found that in some coronal structures the abundances of elements with a low first ionization potential (FIP) <10 eV are enhanced relative to their photospheric abundances. This coronal-to-photospheric abundance ratio, commonly called the FIP bias, is typically 1 for elements with a high-FIP (>10 eV). We have used Extreme Ultraviolet Imaging Spectrometer observations made on 2007 March 13 and 14 over a ≈24 hr period to characterize abundance variations in plumes and interplumes. To assess their elemental composition, we used a differential emission measure analysis, which accounts for the thermal structure of the observed plasma. We used lines from ions of iron, silicon, and sulfur. From these we estimated the ratio of the iron and silicon FIP bias relative to that for sulfur. From the results, we have created FIP-bias-ratio maps. We find that the FIP-bias ratio is sometimes higher in plumes than in interplumes and that this enhancement can be time dependent. These results may help to identify whether plumes or interplumes contribute to the fast solar wind observed in situ and may also provide constraints on the formation and heating mechanisms of plumes.

  14. Efficient electrolyzer for CO2 splitting in neutral water using earth-abundant materials.

    PubMed

    Tatin, Arnaud; Comminges, Clément; Kokoh, Boniface; Costentin, Cyrille; Robert, Marc; Savéant, Jean-Michel

    2016-05-17

    Low-cost, efficient CO2-to-CO+O2 electrochemical splitting is a key step for liquid-fuel production for renewable energy storage and use of CO2 as a feedstock for chemicals. Heterogeneous catalysts for cathodic CO2-to-CO associated with an O2-evolving anodic reaction in high-energy-efficiency cells are not yet available. An iron porphyrin immobilized into a conductive Nafion/carbon powder layer is a stable cathode producing CO in pH neutral water with 90% faradaic efficiency. It is coupled with a water oxidation phosphate cobalt oxide anode in a home-made electrolyzer by means of a Nafion membrane. Current densities of approximately 1 mA/cm(2) over 30-h electrolysis are achieved at a 2.5-V cell voltage, splitting CO2 and H2O into CO and O2 with a 50% energy efficiency. Remarkably, CO2 reduction outweighs the concurrent water reduction. The setup does not prevent high-efficiency proton transport through the Nafion membrane separator: The ohmic drop loss is only 0.1 V and the pH remains stable. These results demonstrate the possibility to set up an efficient, low-voltage, electrochemical cell that converts CO2 into CO and O2 by associating a cathodic-supported molecular catalyst based on an abundant transition metal with a cheap, easy-to-prepare anodic catalyst oxidizing water into O2.

  15. Efficient electrolyzer for CO2 splitting in neutral water using earth-abundant materials

    PubMed Central

    Tatin, Arnaud; Comminges, Clément; Kokoh, Boniface; Costentin, Cyrille; Robert, Marc; Savéant, Jean-Michel

    2016-01-01

    Low-cost, efficient CO2-to-CO+O2 electrochemical splitting is a key step for liquid-fuel production for renewable energy storage and use of CO2 as a feedstock for chemicals. Heterogeneous catalysts for cathodic CO2-to-CO associated with an O2-evolving anodic reaction in high-energy-efficiency cells are not yet available. An iron porphyrin immobilized into a conductive Nafion/carbon powder layer is a stable cathode producing CO in pH neutral water with 90% faradaic efficiency. It is coupled with a water oxidation phosphate cobalt oxide anode in a home-made electrolyzer by means of a Nafion membrane. Current densities of approximately 1 mA/cm2 over 30-h electrolysis are achieved at a 2.5-V cell voltage, splitting CO2 and H2O into CO and O2 with a 50% energy efficiency. Remarkably, CO2 reduction outweighs the concurrent water reduction. The setup does not prevent high-efficiency proton transport through the Nafion membrane separator: The ohmic drop loss is only 0.1 V and the pH remains stable. These results demonstrate the possibility to set up an efficient, low-voltage, electrochemical cell that converts CO2 into CO and O2 by associating a cathodic-supported molecular catalyst based on an abundant transition metal with a cheap, easy-to-prepare anodic catalyst oxidizing water into O2. PMID:27140621

  16. Words Aren't Cheap

    ERIC Educational Resources Information Center

    Rockwell, Mark

    2011-01-01

    Textbooks are a crushingly substantial portion of students' costs every semester, and they're getting more expensive every year. With the cost of some individual textbooks surpassing a monthly cable television bill, students are moving to relieve that economic pressure by renting textbooks instead of buying them new or used. The idea of renting…

  17. Measuring Abundance Ratios from Integrated Light

    NASA Astrophysics Data System (ADS)

    Worthey, G.

    2010-06-01

    Age, overall abundance, and detailed, element-by-element abundances can be extracted from the integrated light of distant galaxies. The method, at its most basic, is merely the comparison of observed spectra with appropriate models. The relative ratios of elements C, N, O, Na, Mg, Ca, Sc, Ti, Cr, Mn, Fe, Co, Ni, Sr, and Ba can be determined to scientifically useful precision. Cases of interest that are borderline because they suffer internal degeneracies (although plenty of signal is present) are Al and the trio C, N, and O. The elements S, K, Cu, Eu, and the noble gases are too difficult to measure, and V is borderline. Changing the relative abundance ratios, even at fixed heavy-element content, changes the temperatures, luminosities, and number densities of the underlying stellar evolution, as well as more direct changes in the spectra of the stars present. The latter effects dominate the spectral shape, while the former effects render age estimation quite difficult.

  18. Chemical Abundances of Compact Planetary Nebulae

    NASA Astrophysics Data System (ADS)

    Lee, Ting-Hui; Shaw, Richard A.; Stanghellini, letizia; Riley, Ben

    2015-08-01

    We present preliminary results from an optical spectroscopic survey of compact planetary nebulae (PNe) in the Galactic disk. This is an ongoing optical+infrared spectral survey of 150 compact PNe to build a deep sample of PN chemical abundances. We obtained optical spectra of PNe with the Southern Astrophysical Research (SOAR) Telescope and Goodman High-Throughput Spectrograph between 2012 and 2015. These data were used to calculate the nebulae diagnostics such as electron temperature and density for each PN, and to derive the elemental abundances of He, N, O Ne, S and Ar. These abundances are vital to understanding the nature of the PNe, and their low- to intermediate-mass progenitor stars.

  19. Rare-earth abundances in chondritic meteorites

    NASA Technical Reports Server (NTRS)

    Evensen, N. M.; Hamilton, P. J.; Onions, R. K.

    1978-01-01

    Fifteen chondrites, including eight carbonaceous chondrites, were analyzed for rare earth element abundances by isotope dilution. Examination of REE for a large number of individual chondrites shows that only a small proportion of the analyses have flat unfractionated REE patterns within experimental error. While some of the remaining analyses are consistent with magmatic fractionation, many patterns, in particular those with positive Ce anomalies, can not be explained by known magmatic processes. Elemental abundance anomalies are found in all major chondrite classes. The persistence of anomalies in chondritic materials relatively removed from direct condensational processes implies that anomalous components are resistant to equilibrium or were introduced at a late stage of chondrite formation. Large-scale segregation of gas and condensate is implied, and bulk variations in REE abundances between planetary bodies is possible.

  20. On the abundance enigma in Ionized Regions

    NASA Astrophysics Data System (ADS)

    Bohigas, J.

    2009-04-01

    In ionized regions with temperature gradients and fluctuations, the ratio of the ion abundance obtained from a recombination line to that found from a collisionally excited line (CEL), or ADF, is smaller than observed (ADF ≥ 2). Larger ADFs are found when there is an additional component that is ≥ 30% colder. The temperature in the cold component must be ≈ 500, 200 and 100 K if the ADF found from an IR CEL is ≃2, 5 and 10. Most of the mass is in the hot region. The total H+ mass has been underestimated if it was found from the intensity of a Balmer line. [O IIII]5007/Hβ images can also render the relative distribution of cold and hot matter. The determination of accurate abundances is forestalled by the fact that observations cannot discriminate light from these components, the existence of distinct abundance sets and insufficient spectral information for the hot region.

  1. Abundance and chemistry of interstellar HOCO(+)

    NASA Technical Reports Server (NTRS)

    Minh, Y. C.; Brewer, M. K.; Irvine, W. M.; Friberg, P.; Johansson, L. E. B.

    1991-01-01

    Column densities of 10 to the 15th/sq cm toward the Galactic center and not more than 10 to the 12th/sq cm for cold dark clouds are derived from observations using an LVG model, and the chemical implications are discussed. The HOCO(+) 4(04)-3(03) line toward Sgr A is mapped. The fractional abundance of HOCO(+) in the Galactic center region was found to be three orders of magnitude larger than predicted by quiescent ion-molecule chemistry and an order of magnitude larger than predicted by an MHD shock model. It is suggested that the possibly high CO2 abundance, and consequently the observed HOCO(+) abundance in the Galactic center, may result from UV photolysis of grain mantles.

  2. INTERSTELLAR ABUNDANCES TOWARD X Per, REVISITED

    SciTech Connect

    Valencic, Lynne A.; Smith, Randall K.

    2013-06-10

    The nearby X-ray binary X Per (HD 24534) provides a useful beacon with which to examine dust grain types and measure elemental abundances in the local interstellar medium (ISM). The absorption features of O, Fe, Mg, and Si along this line of sight were measured using spectra from the Chandra X-Ray Observatory's LETG/ACIS-S and XMM-Newton's RGS instruments, and the Spex software package. The spectra were fit with dust analogs measured in the laboratory. The O, Mg, and Si abundances were compared to those from standard references, and the O abundance was compared to that along lines of sight toward other X-ray binaries. The results are as follows. First, it was found that a combination of MgSiO{sub 3} (enstatite) and Mg{sub 1.6}Fe{sub 0.4}SiO{sub 4} (olivine) provided the best fit to the O K edge, with N(MgSiO{sub 3})/N(Mg{sub 1.6}Fe{sub 0.4}SiO{sub 4}) = 3.4. Second, the Fe L edge could be fit with models that included metallic iron, but it was not well described by the laboratory spectra currently available. Third, the total abundances of O, Mg, and Si were in very good agreement with that of recently re-analyzed B stars, suggesting that they are good indicators of abundances in the local ISM, and the depletions were also in agreement with expected values for the diffuse ISM. Finally, the O abundances found from X-ray binary absorption spectra show a similar correlation with Galactocentric distances as seen in other objects.

  3. OH vertical column abundance - Tropical measurements

    NASA Astrophysics Data System (ADS)

    Burnett, Clyde R.; Minschwaner, Kenneth R.; Burnett, Elizabeth B.

    1990-09-01

    Measurements of the vertical column abundance of atmospheric hydroxyl (OH) have been made during the period 1987-1989 at the National Weather Service (NWS) station at Moen, Truk, Federated States of Micronesia (7 deg N, 152 deg E). A total of 384 independent data sets was obtained. Tropical OH abundance levels average about 22 percent above corresponding mid-latitude values, with OH levels during late winter and early spring up to 50 percent above those observed at 40 deg N. Stratospheric wind and temperature data obtained from the daily NWS radiosonde data are examined for correlations with the OH results.

  4. OH vertical column abundance - Tropical measurements

    NASA Technical Reports Server (NTRS)

    Burnett, Clyde R.; Minschwaner, Kenneth R.; Burnett, Elizabeth B.

    1990-01-01

    Measurements of the vertical column abundance of atmospheric hydroxyl (OH) have been made during the period 1987-1989 at the National Weather Service (NWS) station at Moen, Truk, Federated States of Micronesia (7 deg N, 152 deg E). A total of 384 independent data sets was obtained. Tropical OH abundance levels average about 22 percent above corresponding mid-latitude values, with OH levels during late winter and early spring up to 50 percent above those observed at 40 deg N. Stratospheric wind and temperature data obtained from the daily NWS radiosonde data are examined for correlations with the OH results.

  5. Dispersion in DLA metallicities and deuterium abundances

    NASA Astrophysics Data System (ADS)

    Dvorkin, Irina; Silk, Joseph; Vangioni, Elisabeth; Petitjean, Patrick; Olive, Keith A.

    2017-03-01

    Recent chemical abundance measurements of damped Lyman-alpha absorbers (DLAs) revealed a large intrinsic scatter in their metallicities. We discuss a semi-analytic model that was specifically designed to study this scatter by tracing the chemical evolution of the interstellar matter in small regions of the Universe with different mean density, from over- to underdense regions. It is shown that different histories of structure formation in these regions are reflected in the chemical properties of the proto-galaxies. We also address deuterium abundance measurements, which constitute a complementary probe of the star formation and infall histories.

  6. Electrical Injuries

    MedlinePlus

    ... your injuries are depends on how strong the electric current was, what type of current it was, how it moved through your body, and how long you were exposed. Other factors include how ... you should see a doctor. You may have internal damage and not realize it.

  7. ABUNDANT OR RARE? A HYBRID APPROACH FOR DETERMINING SPECIES RELATIVE ABUNDANCE AT AN ECOREGOIONAL SCALE

    EPA Science Inventory

    Everyone knows what abundant and rare species are, but quantifying the concept proves elusive. As part of an EPA/USGS project to assess near-coastal species vulnerability to climate change affects, we designed a hybrid approach to determine species relative abundance at an ecoreg...

  8. ABUNDANT OR RARE? A HYBRID APPROACH FOR DETERMINING SPECIES RELATIVE ABUNDANCE AT AN ECOREGOIONAL SCALE - 2014

    EPA Science Inventory

    Everyone knows what abundant and rare species are, but quantifying the concept proves elusive. As part of an EPA/USGS project to assess near-coastal species vulnerability to climate change affects, we designed a hybrid approach to determine species relative abundance at an ecoreg...

  9. Empirical oxygen abundances and physical conditions for relatively low abundance H II regions

    SciTech Connect

    Skillman, E.D. )

    1989-12-01

    The utility of the emission-line ratio (3727 + 4959 + 5007 A)/H-beta as an estimate of the total oxygen abundance in H II regions of low abundance (less than 10 percent of the solar value) is discussed. Using both observational data where the 4363A line is measured and model H II regions it is concluded that, for low abundance systems, total oxygen abundances can be determined with an accuracy of + or - 0.2 dex in the absence of a 4363A measurement. An attempt is made to study the average behavior of the stellar effective temperature (Teff) and ionization parameter (U) with changing abundance in low abundance systems. It is shown that some diagnostic methods which are viable for high abundance systems are not capable of uniquely determining Teff and U in low abundance systems. The most promising method of determining Teff and U requires measuring emission lines of forbidden O II, O III, S II, and S III. 53 refs.

  10. Comparison of accelerated solvent extraction and quick, easy, cheap, effective, rugged and safe method for extraction and determination of pharmaceuticals in vegetables.

    PubMed

    Chuang, Ya-Hui; Zhang, Yingjie; Zhang, Wei; Boyd, Stephen A; Li, Hui

    2015-07-24

    Land application of biosolids and irrigation with reclaimed water in agricultural production could result in accumulation of pharmaceuticals in vegetable produce. To better assess the potential human health impact from long-term consumption of pharmaceutical-contaminated vegetables, it is important to accurately quantify the amount of pharmaceuticals accumulated in vegetables. In this study, a quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed and optimized to extract multiple classes of pharmaceuticals from vegetables, which were subsequently quantified by liquid chromatography coupled to tandem mass spectrometry. For the eleven target pharmaceuticals in celery and lettuce, the extraction recovery of the QuEChERS method ranged from 70.1 to 118.6% with relative standard deviation <20%, and the method detection limit was achieved at the levels of nanograms of pharmaceuticals per gram of vegetables. The results revealed that the performance of the QuEChERS method was comparable to, or better than that of accelerated solvent extraction (ASE) method for extraction of pharmaceuticals from plants. The two optimized extraction methods were applied to quantify the uptake of pharmaceuticals by celery and lettuce growing hydroponically. The results showed that all the eleven target pharmaceuticals could be absorbed by the vegetables from water. Compared to the ASE method, the QuEChERS method offers the advantages of short time and reduced costs of sample preparation, and less amount of organic solvents used. The established QuEChERS method could be used to determine the accumulation of multiple classes of pharmaceutical residues in vegetables and other plants, which is needed to evaluate the quality and safety of agricultural produce consumed by humans.

  11. Determination of ribavirin in chicken muscle by quick, easy, cheap, effective, rugged and safe method and liquid chromatography-tandem mass spectrometry.

    PubMed

    Wu, Yin-Liang; Chen, Ruo-Xia; Zhu, Lie; Lv, Yan; Zhu, Yong; Zhao, Jian

    2016-02-15

    A new analytical method for the determination of ribavirin in chicken muscle using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method and liquid chromatography-tandem mass spectrometry (LC-MS-MS) was developed and validated. Samples were extracted with acidified methanol (methanol:acetic acid, 99:1, v/v). The extract was further purified by QuEChERS method using primary-secondary amine (PSA) and C18. Finally, the extract was dried by nitrogen under 45°C and reconstituted in water. The separation was performed on a Hypercarb analytical column under a gradient elution. The mobile phase was composed of water buffered with ammonium acetate (2.0mM) and acetonitrile. The proposed method was validated according to the European Commission Decision 2002/657/EC. The values of the decision limit (CCα) and the detection capability (CCβ) were 1.1 and 1.5μg/kg, respectively. The mean recoveries of ribavirin ranged from 94.2% to 99.2%. The repeatability (expressed as coefficient of variation, CVr) of the method ranged from 4.5% to 4.9% and the reproducibility (CVR) of the method ranged from 4.8% to 5.4%. The method is demonstrated to be suitable for the determination of ribavirin in chicken muscle in conformity with the current EU performance requirements through validation. The total time required for the analysis of one sample, including sample preparation, was about 45min.

  12. Simultaneous determination of florfenicol with its metabolite based on modified quick, easy, cheap, effective, rugged, and safe sample pretreatment and evaluation of their degradation behavior in agricultural soils.

    PubMed

    Xu, Mingfei; Qian, Mingrong; Zhang, Hu; Ma, Junwei; Wang, Jianmei; Wu, Huizhen

    2015-01-01

    A simple and simultaneous method for the determination of florfenicol and its metabolite florfenicol amine in agricultural soils using modified quick, easy, cheap, effective, rugged, and safe sample pretreatment and reversed-phase high-performance liquid chromatography with tandem mass spectrometry is presented. Florfenicol and its metabolite florfenicol amine residues in agricultural soils were extracted with alkalized acetonitrile and an aliquot was cleaned up with Si(CH2)3NH(CH2)2NH2 and C18 sorbent, which were powder materials. High-performance liquid chromatography with tandem mass spectrometry was applied to simultaneously determine the level of florfenicol and florfenicol amine in agricultural soils. Excellent linearity was achieved for florfenicol and florfenicol amine over a range of concentrations from 0.1-500 μg/L with coefficients more than 0.99. Average recoveries at four different levels (0.005, 0.05, 0.5, and 5.0 mg/kg) for florfenicol and florfenicol amine ranged from 73.6-94.9% with relative standard deviations of 2.9-12.5%. The limits of detection for florfenicol and florfenicol amine in agricultural soils were 2.0 μg/kg, and the limits of quantification were 6.0 μg/kg. Based on this method, the degradation behavior of florfenicol and its metabolite florfenicol amine in three soils (Nanchang, Hangzhou, and Changchun) under sterilized and native conditions was investigated and the transformation rate of florfenicol amine from florfenicol was evaluated.

  13. Development of a modified QUick, Easy, CHeap, Effective, Rugged and Safe method for the determination of multi-class antimicrobials in vegetables by liquid chromatography tandem mass spectrometry.

    PubMed

    Hu, Fengyang; Bian, Kui; Liu, Yahong; Su, Yijuan; Zhou, Tong; Song, Xuqin; He, Limin

    2014-11-14

    A modified quick, easy, cheap, efficient, rugged and safe (QuEChERS) method coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed for rapid determination of 26 veterinary antimicrobials in vegetables. Samples were extracted by single-phase extraction with acetonitrile-methanol (85:15, v/v) and citric buffer solution, followed by liquid-liquid partitioning with the addition of anhydrous magnesium sulfate and sodium chloride. A dispersive solid-phase extraction with primary secondary amine was applied for cleanup. Concentration and solvent exchange was performed prior to LC-MS/MS analysis. All matrix-matched calibration curves were linear with correlation coefficients (r) over 0.99. Recoveries for all the analytes spiked at 0.5 (1 or 1.5), 5 and 50 ng/mL were in the range of 60.0-98.0%, except for sulfaquinoxaline, sulfaclozine and doxycycline, with relative standard deviations below 25% for the low concentration level, 20% for the medium and 15% for the high. The decision limits and the detection capabilities of the analytes ranged from 0.005 to 0.5 μg/kg and from 0.02 to 1.5 μg/kg, respectively. The method was developed and validated in accordance with romaine lettuce matrix, and higher recovery rates were obtained from the other five kinds of vegetables including white radish, Chinese cabbage, cucumber, string bean and green pepper. Matrix effects of different vegetables were evaluated and signal suppression effect was observed for the majority of 26 analytes. Finally, the method was applied to the analysis of real samples collected from the agricultural areas in the vicinity of local pig farms, and the phenomenon of vegetables contaminated by antimicrobials residues is provoking.

  14. Coupling of the coronal helium abundance to the solar wind

    NASA Technical Reports Server (NTRS)

    Hansteen, Viggo H.; Leer, Egil; Holzer, Thomas E.

    1994-01-01

    Models of the transition region-corona-solar wind system are investigated in order to find the coronal helium abundance and to study the role played by coronal helium in controlling the solar wind proton flux. The thermal force on alpha-particles in the transition region sets the flow of helium into the corona. The frictional coupling between alpha-particles and protons and/or the electric polarization field determines the proton flux in the solar wind as well as the fate of the coronal helium content. The models are constructed by solving the time-dependent population and momentum equations for all species of hydrogen and helium in an atmosphere with a given temperature profile. Several temperature profiles are considered in order to very the roles of frictional coupling and electric polarization field in the solar wind, and the thermal force in the transition region. Steady-state solutions are found for coronae with a hydrogen flux at 1 AU of 1.0 x 10(exp 9)/cm(exp 2)/sec or larger. For coronae with lower hydrogen fluxes, the helium flux into the corona is larger than the flux 'pulled out' by the solar wind protons, and solutions with increasing coronal helium content are found. The timescale for forming a helium-filled corona, that may allow for a steady outflow, is long compared to the mixing time for the corona.

  15. The Abundance of Large Arcs From CLASH

    NASA Astrophysics Data System (ADS)

    Xu, Bingxiao; Postman, Marc; Meneghetti, Massimo; Coe, Dan A.; Clash Team

    2015-01-01

    We have developed an automated arc-finding algorithm to perform a rigorous comparison of the observed and simulated abundance of large lensed background galaxies (a.k.a arcs). We use images from the CLASH program to derive our observed arc abundance. Simulated CLASH images are created by performing ray tracing through mock clusters generated by the N-body simulation calibrated tool -- MOKA, and N-body/hydrodynamic simulations -- MUSIC, over the same mass and redshift range as the CLASH X-ray selected sample. We derive a lensing efficiency of 15 ± 3 arcs per cluster for the X-ray selected CLASH sample and 4 ± 2 arcs per cluster for the simulated sample. The marginally significant difference (3.0 σ) between the results for the observations and the simulations can be explained by the systematically smaller area with magnification larger than 3 (by a factor of ˜4) in both MOKA and MUSIC mass models relative to those derived from the CLASH data. Accounting for this difference brings the observed and simulated arc statistics into full agreement. We find that the source redshift distribution does not have big impact on the arc abundance but the arc abundance is very sensitive to the concentration of the dark matter halos. Our results suggest that the solution to the "arc statistics problem" lies primarily in matching the cluster dark matter distribution.

  16. In Abundance: Networked Participatory Practices as Scholarship

    ERIC Educational Resources Information Center

    Stewart, Bonnie E.

    2015-01-01

    In an era of knowledge abundance, scholars have the capacity to distribute and share ideas and artifacts via digital networks, yet networked scholarship often remains unrecognized within institutional spheres of influence. Using ethnographic methods including participant observation, interviews, and document analysis, this study investigates…

  17. Will Abundant Natural Gas Solve Climate Change?

    NASA Astrophysics Data System (ADS)

    McJeon, H. C.; Edmonds, J.; Bauer, N.; Leon, C.; Fisher, B.; Flannery, B.; Hilaire, J.; Krey, V.; Marangoni, G.; Mi, R.; Riahi, K.; Rogner, H.; Tavoni, M.

    2015-12-01

    The rapid deployment of hydraulic fracturing and horizontal drilling technologies enabled the production of previously uneconomic shale gas resources in North America. Global deployment of these advanced gas production technologies could bring large influx of economically competitive unconventional gas resources to the energy system. It has been hoped that abundant natural gas substituting for coal could reduce carbon dioxide (CO2) emissions, which in turn could reduce climate forcing. Other researchers countered that the non-CO2 greenhouse gas (GHG) emissions associated with shale gas production make its lifecycle emissions higher than those of coal. In this study, we employ five state-of-the-art integrated assessment models (IAMs) of energy-economy-climate systems to assess the full impact of abundant gas on climate change. The models show large additional natural gas consumption up to +170% by 2050. The impact on CO2 emissions, however, is found to be much smaller (from -2% to +11%), and a majority of the models reported a small increase in climate forcing (from -0.3% to +7%) associated with the increased use of abundant gas. Our results show that while globally abundant gas may substantially change the future energy market equilibrium, it will not significantly mitigate climate change on its own in the absence of climate policies.

  18. Heavy element abundances and massive star formation

    NASA Technical Reports Server (NTRS)

    Wang, Boqi; Silk, Joseph

    1993-01-01

    The determination of the stellar initial mass function (IMF) remains a great challenge in astronomy. In the solar neighborhood, the IMF is reasonable well determined for stellar masses from about 0.1 to 60 solar mass. However, outside the solar neighborhood, the IMF is poorly known. Among those frequently discussed arguments favoring a different IMF outside the solar neighborhood are the estimated time to consume the remaining gas in spiral galaxies, and the high rate of forming massive stars in starburst galaxies. An interesting question then is whether there may be an independent way of testing possible variations in the IMF. Indeed, the heavy elements in the interstellar medium are mostly synthesized in massive stars, so increasing, or decreasing, the fraction of massive stars naturally leads to a variation in the heavy element yield, and thus, the metallicity. The observed abundance should severely constrain any deviations of the IMF from the locally determined IMF. We focus on element oxygen, which is the most abundant heavy element in the interstellar medium. Oxygen is ejected only by massive stars that can become Type 1 supernovae, and the oxygen abundance is, therefore, a sensitive function of the fraction of massive stars in the IMF. Adopting oxygen enables us to avoid uncertainties in Type 1 supernovae. We use the nucleosynthesis results to calculate the oxygen yield for given IMF. We then calculate the oxygen abundance in the interstellar medium assuming instantaneous recycling of oxygen.

  19. Considerations when quantitating protein abundance by immunoblot.

    PubMed

    McDonough, Alicia A; Veiras, Luciana C; Minas, Jacqueline N; Ralph, Donna Lee

    2015-03-15

    The development of the immunoblot to detect and characterize a protein with an antisera, even in a crude mixture, was a breakthrough with wide-ranging and unpredictable applications across physiology and medicine. Initially, this technique was viewed as a tool for qualitative, not quantitative, analyses of proteins because of the high number of variables between sample preparation and detection with antibodies. Nonetheless, as the immunoblot method was streamlined and improved, investigators pushed it to quantitate protein abundance in unpurified samples as a function of treatment, genotype, or pathology. This short review, geared at investigators, reviewers, and critical readers, presents a set of issues that are of critical importance for quantitative analysis of protein abundance: 1) Consider whether tissue samples are of equivalent integrity and assess how handling between collection and assay influences the apparent relative abundance. 2) Establish the specificity of the antiserum for the protein of interest by providing clear images, molecular weight markers, positive and negative controls, and vendor details. 3) Provide convincing evidence for linearity of the detection system by assessing signal density as a function of sample loaded. 4) Recognize that loading control proteins are rarely in the same linear range of detection as the protein of interest; consider protein staining of the gel or blot. In summary, with careful attention to sample integrity, antibody specificity, linearity of the detection system, and acceptable loading controls, investigators can implement quantitative immunoblots to convincingly assess protein abundance in their samples.

  20. Toward Reliable Estimates of Abundance: Comparing Index Methods to Assess the Abundance of a Mammalian Predator

    PubMed Central

    Güthlin, Denise; Storch, Ilse; Küchenhoff, Helmut

    2014-01-01

    Due to time and financial constraints indices are often used to obtain landscape-scale estimates of relative species abundance. Using two different field methods and comparing the results can help to detect possible bias or a non monotonic relationship between the index and the true abundance, providing more reliable results. We used data obtained from camera traps and feces counts to independently estimate relative abundance of red foxes in the Black Forest, a forested landscape in southern Germany. Applying negative binomial regression models, we identified landscape parameters that influence red fox abundance, which we then used to predict relative red fox abundance. We compared the estimated regression coefficients of the landscape parameters and the predicted abundance of the two methods. Further, we compared the costs and the precision of the two field methods. The predicted relative abundances were similar between the two methods, suggesting that the two indices were closely related to the true abundance of red foxes. For both methods, landscape diversity and edge density best described differences in the indices and had positive estimated effects on the relative fox abundance. In our study the costs of each method were of similar magnitude, but the sample size obtained from the feces counts (262 transects) was larger than the camera trap sample size (88 camera locations). The precision of the camera traps was lower than the precision of the feces counts. The approach we applied can be used as a framework to compare and combine the results of two or more different field methods to estimate abundance and by this enhance the reliability of the result. PMID:24743565

  1. Toward reliable estimates of abundance: comparing index methods to assess the abundance of a Mammalian predator.

    PubMed

    Güthlin, Denise; Storch, Ilse; Küchenhoff, Helmut

    2014-01-01

    Due to time and financial constraints indices are often used to obtain landscape-scale estimates of relative species abundance. Using two different field methods and comparing the results can help to detect possible bias or a non monotonic relationship between the index and the true abundance, providing more reliable results. We used data obtained from camera traps and feces counts to independently estimate relative abundance of red foxes in the Black Forest, a forested landscape in southern Germany. Applying negative binomial regression models, we identified landscape parameters that influence red fox abundance, which we then used to predict relative red fox abundance. We compared the estimated regression coefficients of the landscape parameters and the predicted abundance of the two methods. Further, we compared the costs and the precision of the two field methods. The predicted relative abundances were similar between the two methods, suggesting that the two indices were closely related to the true abundance of red foxes. For both methods, landscape diversity and edge density best described differences in the indices and had positive estimated effects on the relative fox abundance. In our study the costs of each method were of similar magnitude, but the sample size obtained from the feces counts (262 transects) was larger than the camera trap sample size (88 camera locations). The precision of the camera traps was lower than the precision of the feces counts. The approach we applied can be used as a framework to compare and combine the results of two or more different field methods to estimate abundance and by this enhance the reliability of the result.

  2. Thermal relics: Do we know their abundances

    NASA Technical Reports Server (NTRS)

    Kamionkowski, Marc; Turner, Michael S.

    1990-01-01

    The relic abundance of a particle species that was once in thermal equilibrium in the expanding Universe depends upon a competition between the annihilation rate of the species and the expansion rate of the Universe. Assuming that the Universe is radiation dominated at early times the relic abundance is easy to compute and well known. At times earlier than about 1 sec after the bang there is little or no evidence that the Universe had to be radiation dominated, although that is the simplest and standard assumption. Because early-Universe relics are of such importance both to particle physics and to cosmology, three nonstandard possibilities are considered in detail for the Universe at the time a species' abundance froze in: energy density dominated by shear (i.e., anisotropic expansion), energy density dominated by some other nonrelativistic species, and energy density dominated by the kinetic energy of the scalar field that sets the gravitational constant in a Brans-Dicke-Jordan cosmological mode. In the second case the relic abundance is less than the standard value, while in the other two cases it can be enhanced by a significant factor. Two other more exotic possibilities for enhancing the relic abundance of a species are also mentioned--a larger value of Newton's constant at early times (e.g., as might occur in superstring or Kaluza-Klein theories) or a component of the energy density at early times with a very stiff equation of state (p greater than rho/3), e.g., a scalar field phi with potential V(phi) = Beta /phi/ (exp n) with n greater than 4. Results have implications for dark matter searches and searches for particle relics in general.

  3. Chemical abundances and kinematics of barium stars

    NASA Astrophysics Data System (ADS)

    de Castro, D. B.; Pereira, C. B.; Roig, F.; Jilinski, E.; Drake, N. A.; Chavero, C.; Sales Silva, J. V.

    2016-07-01

    In this paper, we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scaleheight, radial velocities, abundances of the Na, Al, α-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local thermodynamic equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG. We found that the metallicities, the temperatures and the surface gravities for barium stars cannot be represented by a single Gaussian distribution. The abundances of α-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heavy-element abundance pattern as given by the ratio [s/Fe], we found that the barium stars present several degrees of enrichment. We also obtained the [hs/ls] ratio by measuring the photospheric abundances of the Ba-peak and the Zr-peak elements. Our results indicated that the [s/Fe] and the [hs/ls] ratios are strongly anticorrelated with the metallicity. Our kinematical analysis showed that 90 per cent of the barium stars belong to the thin disc population. Based on their luminosities, none of the barium stars are luminous enough to be an asymptotic giant branch star, nor to become self-enriched in the s-process elements. Finally, we determined that the barium stars also follow an age-metallicity relation.

  4. Heterotypic gap junctions at glutamatergic mixed synapses are abundant in goldfish brain

    PubMed Central

    Rash, John E.; Kamasawa, Naomi; Vanderpool, Kimberly G.; Yasumura, Thomas; O'Brien, John; Nannapaneni, Srikant; Pereda, Alberto E.; Nagy, James I.

    2014-01-01

    Gap junctions provide for direct intercellular electrical and metabolic coupling. The abundance of gap junctions at “large myelinated club ending” synapses on Mauthner cells of the teleost brain provided a convenient model to correlate anatomical and physiological properties of electrical synapses. There, presynaptic action potentials were found to evoke short-latency electrical “pre-potentials” immediately preceding their accompanying glutamate-induced depolarizations, making these the first unambiguously identified “mixed” (i.e., chemical plus electrical) synapses in the vertebrate CNS. We recently showed that gap junctions at these synapses exhibit asymmetric electrical resistance (i.e., electrical rectification), which we correlated with total molecular asymmetry of connexin composition in their apposing gap junction hemiplaques, with Cx35 restricted to axon terminal hemiplaques and Cx34.7 restricted to apposing Mauthner cell plasma membranes. We now show that similarly heterotypic neuronal gap junctions are abundant throughout goldfish brain, with labeling exclusively for Cx35 in presynaptic hemiplaques and exclusively for Cx34.7 in postsynaptic hemiplaques. Moreover, the vast majority of these asymmetric gap junctions occur at glutamatergic axon terminals. The widespread distribution of heterotypic gap junctions at glutamatergic mixed synapses throughout goldfish brain and spinal cord implies that pre- vs. postsynaptic asymmetry at electrical synapses evolved early in the chordate lineage. We propose that the advantages of the molecular and functional asymmetry of connexins at electrical synapses that are so prominently expressed in the teleost CNS are unlikely to have been abandoned in higher vertebrates. However, to create asymmetric coupling in mammals, where most gap junctions are composed of Cx36 on both sides, would require some other mechanism, such as differential phosphorylation of connexins on opposite sides of the same gap junction or

  5. Heterotypic gap junctions at glutamatergic mixed synapses are abundant in goldfish brain.

    PubMed

    Rash, J E; Kamasawa, N; Vanderpool, K G; Yasumura, T; O'Brien, J; Nannapaneni, S; Pereda, A E; Nagy, J I

    2015-01-29

    Gap junctions provide for direct intercellular electrical and metabolic coupling. The abundance of gap junctions at "large myelinated club ending (LMCE)" synapses on Mauthner cells (M-cells) of the teleost brain provided a convenient model to correlate anatomical and physiological properties of electrical synapses. There, presynaptic action potentials were found to evoke short-latency electrical "pre-potentials" immediately preceding their accompanying glutamate-induced depolarizations, making these the first unambiguously identified "mixed" (i.e., chemical plus electrical) synapses in the vertebrate CNS. We recently showed that gap junctions at these synapses exhibit asymmetric electrical resistance (i.e., electrical rectification), which we correlated with total molecular asymmetry of connexin composition in their apposing gap junction hemiplaques, with connexin35 (Cx35) restricted to axon terminal hemiplaques and connexin34.7 (Cx34.7) restricted to apposing M-cell plasma membranes. We now show that similarly heterotypic neuronal gap junctions are abundant throughout goldfish brain, with labeling exclusively for Cx35 in presynaptic hemiplaques and exclusively for Cx34.7 in postsynaptic hemiplaques. Moreover, the vast majority of these asymmetric gap junctions occur at glutamatergic axon terminals. The widespread distribution of heterotypic gap junctions at glutamatergic mixed synapses throughout goldfish brain and spinal cord implies that pre- vs. postsynaptic asymmetry at electrical synapses evolved early in the chordate lineage. We propose that the advantages of the molecular and functional asymmetry of connexins at electrical synapses that are so prominently expressed in the teleost CNS are unlikely to have been abandoned in higher vertebrates. However, to create asymmetric coupling in mammals, where most gap junctions are composed of connexin36 (Cx36) on both sides, would require some other mechanism, such as differential phosphorylation of connexins on

  6. Electricity unplugged

    NASA Astrophysics Data System (ADS)

    Karalis, Aristeidis

    2009-02-01

    The judge was driving back late one cold winter night. Entering the garage, the battery-charging indicator in his wirelessly powered electric car came on. "Home at last," crossed his mind. He swiped his personal smartcard on the front-door detector to be let in. He heard a "charging" beep from his mobile phone. The blinking cursor on the half-finished e-mail on the laptop had been waiting all day on the side table. He picked the computer up and walked towards his desk. "Good evening, your honour. Your wirelessly heated robe," said the butler-robot as it approached from the kitchen. Putting on the electric garment, he sat on the medical desk chair. His artificial heart was now beating faster.

  7. Electric power

    SciTech Connect

    Chase, M.

    1988-01-01

    This text examines the critical problems faced by the electric power industry, shown in the context of a detailed description of the history and development of the industry. A new industry initiative is proposed that will allow for a more effective response to industry fluctuations. Topics covered include developments in power technology federal nuclear power regulation and legislation, environmentalism and conservationism, industry financial problems, capital minimization, and responses to utility responsibility.

  8. Electric Car

    NASA Technical Reports Server (NTRS)

    1977-01-01

    NASA's Lewis Research Center undertook research toward a practical, economical battery with higher energy density. Borrowing from space satellite battery technology, Lewis came up with a nickel-zinc battery that promises longer life and twice the range of the lead-acid counterpart. Lewis researchers fabricated a prototype battery and installed it in an Otis P-500 electric utility van, using only the battery space already available and allowing battery weight equal to that of the va's conventional lead-acid battery

  9. Ubiquitous monitoring of electrical household appliances.

    PubMed

    Lloret, Jaime; Macías, Elsa; Suárez, Alvaro; Lacuesta, Raquel

    2012-11-07

    The number of appliances at home is increasing continuously, mainly because they make our lives easier. Currently, technology is integrated in all objects of our daily life. TCP/IP let us monitor our home in real time and check ubiquitously if something is happening at home. Bearing in mind this idea, we have developed a low-cost system, which can be used in any type of electrical household appliance that takes information from the appliance and posts the information to the Twitter Social network. Several sensors placed in the household appliances gather the sensed data and send them wired or wirelessly, depending on the case, using small and cheap devices to a gateway located in the home. This gateway takes decisions, based on the received data, and sends notifications to Twitter. We have developed a software application that takes the values and decides when to issue an alarm to the registered users (Twitter friends of our smart home). The performance of our system has been measured taking into account the home network (using IEEE 802.3u and IEEE 802.11g) and the data publishing in Twitter. As a result, we have generated an original product and service for any electrical household appliance, regardless of the model and manufacturer, that helps home users improve their quality of life. The paper also shows that there is no system with the same innovative features like the ones presented in this paper.

  10. Ubiquitous Monitoring of Electrical Household Appliances

    PubMed Central

    Lloret, Jaime; Macías, Elsa; Suárez, Alvaro; Lacuesta, Raquel

    2012-01-01

    The number of appliances at home is increasing continuously, mainly because they make our lives easier. Currently, technology is integrated in all objects of our daily life. TCP/IP let us monitor our home in real time and check ubiquitously if something is happening at home. Bearing in mind this idea, we have developed a low-cost system, which can be used in any type of electrical household appliance that takes information from the appliance and posts the information to the Twitter Social network. Several sensors placed in the household appliances gather the sensed data and send them wired or wirelessly, depending on the case, using small and cheap devices to a gateway located in the home. This gateway takes decisions, based on the received data, and sends notifications to Twitter. We have developed a software application that takes the values and decides when to issue an alarm to the registered users (Twitter friends of our smart home). The performance of our system has been measured taking into account the home network (using IEEE 802.3u and IEEE 802.11g) and the data publishing in Twitter. As a result, we have generated an original product and service for any electrical household appliance, regardless of the model and manufacturer, that helps home users improve their quality of life. The paper also shows that there is no system with the same innovative features like the ones presented in this paper. PMID:23202205

  11. Chemical Cartography in the Milky Way with SDSS/APOGEE: Multi-element abundances and abundance ratio variations

    NASA Astrophysics Data System (ADS)

    Holtzman, Jon A.; Hasselquist, Sten; Johnson, Jennifer; Bird, Jonathan C.; Majewski, Steven R.; SDSS/APOGEE Team

    2017-01-01

    The SDSS/APOGEE project is measuring abundances of multiple elements for several hundred thousand stars across the Milky Way. These allow the mapping of abundances and abundance ratio variations. Results will be presented for multiple abundance ratios across of the Galactic disk. The interpretation of mean abundance maps is complicated by variations in star formation history across the disk and by changing abundance ratios that result from an overall metallicity gradient. Variations in chemical abundance sequences, however, show the potential for using abundance ratios to track the movement of stars through the disk, and provide key information for constraining Galaxy formation and chemical evolution models.

  12. Deuterium Abundance in Consciousness and Current Cosmology

    NASA Astrophysics Data System (ADS)

    Rauscher, Elizabeth A.

    We utilize the deuterium-hydrogen abundances and their role in setting limits on the mass and other conditions of cosmogenesis and cosmological evolution. We calculate the dependence of a set of physical variables such as density, temperature, energy mass, entropy and other physical variable parameters through the evolution of the universe under the Schwarzschild conditions as a function from early to present time. Reconciliation with the 3°K and missing mass is made. We first examine the Schwarzschild condition; second, the geometrical constraints of a multidimensional Cartesian space on closed cosmologies, and third we will consider the cosmogenesis and evolution of the universe in a multidimensional Cartesian space, obeying the Schwarzschild condition. Implications of this model for matter creation are made. We also examine experimental evidence for closed versus open cosmologies; x-ray detection of the "missing mass" density. Also the interstellar deuterium abundance, along with the value of the Hubble constant set a general criterion on the value of the curvature constant, k. Once the value of the Hubble constant, H is determined, the deuterium abundance sets stringent restrictions on the value of the curvature constant k by an detailed discussion is presented. The experimental evidences for the determination of H and the primary set of coupled equations to determine D abundance is given. 'The value of k for an open, closed, or flat universe will be discussed in terms of the D abundance which will affect the interpretation of the Schwarzschild, black hole universe. We determine cosmology solutions to Einstein's field obeying the Schwarzschild solutions condition. With this model, we can form a reconciliation of the black hole, from galactic to cosmological scale. Continuous creation occurs at the dynamic blackhole plasma field. We term this new model the multiple big bang or "little whimper model". We utilize the deuteriumhydrogen abundances and their role in

  13. Rapid quick, easy, cheap, effective, rugged, and safe extraction with novel phospholipid cleanup: A streamlined ultra high performance liquid chromatography with ultraviolet detection approach for screening polycyclic aromatic hydrocarbons in avian blood cells and plasma.

    PubMed

    Provatas, Anthony A; Yevdokimov, Alexander V; King, Cory A; Gatley, Emma L; Stuart, James D; Evers, David C; Perkins, Christopher R

    2015-08-01

    A streamlined method has been developed for the isolation and analysis of polycyclic aromatic hydrocarbons in avian blood cells and plasma utilizing quick, easy, cheap, effective, rugged, and safe extraction in combination with novel phospholipid cleanup technology. A variety of traditional extraction and cleanup techniques have been employed in the preparation and analysis of polycyclic aromatic hydrocarbonsin a variety of matrices; liquid-liquid partitioning, solid-phase extractions, gel permeation chromatography, and column chromatography are all effective techniques, however they are laborious and time consuming processes that require large amounts of solvent. Using quick, easy, cheap, effective, rugged, and safe extraction coupled with phospholipid cleanup, samples can be quickly screened while maintaining high throughput and sensitivity. With a liquid chromatography approach, analysis times may be kept short at 16 min while maintaining high analyte recovery. Recoveries in quality control samples ranged from 70 to 109%, with average surrogate recoveries of 80.6 ± 1.10%. The result of using a quick, easy, cheap, effective, rugged, and safe extraction approach in conjunction with phospholipid cleanup is a methodology that significantly reduces sample preparation time and solvent use while maintaining high sensitivity and reproducibility.

  14. The Abundances of Nuclides Magnesium in the Atmospheres of Arcturus and Aldebaran

    NASA Astrophysics Data System (ADS)

    Gorbanjeva, T. I.; Kantzen, L. E.; Komarov, N. S.

    The abundances of nuclides magnesium in the atmospheres of Arcturus and Aldebaran thick and thin disks of Galaxy have been studied. The stars have various chromospheric activity. We used the new data on molecular constants of radiation for every electrically- vibrationally-rotating line of molecular system A2 Π-X2 Σ for MgH. The synthetic spectra were calculated. The values determined are generally close, but not equal, to the solar ratios.

  15. Lithium Abundance in M3 Red Giant

    NASA Astrophysics Data System (ADS)

    Givens, Rashad; Pilachowski, Catherine A.

    2015-01-01

    We present the abundance of lithium in the red giant star vZ 1050 (SK 291) in the globular cluster M3. A previous survey of giants in the cluster showed that like IV-101, vZ 1050 displays a prominent Li I 6707 Å feature. vZ 1050 lies on the blue side of the red giant branch about 1.3 magnitudes above the level of the horizontal branch, and may be an asymptotic giant branch star. A high resolution spectrum of M3 vZ1050 was obtained with the ARC 3.5m telescope and the ARC Echelle Spectrograph (ARCES). Atmospheric parameters were determined using Fe I and Fe II lines from the spectrum using the MOOG spectral analysis program, and the lithium abundance was determined using spectrum synthesis.

  16. THE OXYGEN ABUNDANCE IN THE SOLAR NEIGHBORHOOD

    SciTech Connect

    RodrIguez, Monica; Delgado-Inglada, Gloria E-mail: gloria@inaoep.mx

    2011-06-01

    We present a homogeneous analysis of the oxygen abundance in five H II regions and eight planetary nebulae (PNe) located at distances lower than 2 kpc and with available spectra of high quality. We find that both the collisionally excited lines (CELs) and recombination lines imply that the PNe are overabundant in oxygen by about 0.2 dex. An explanation that reconciles the oxygen abundances derived with CELs for H II regions and PNe with the values found for B stars, the Sun, and the diffuse interstellar medium (ISM) requires the presence in H II regions of an organic refractory dust component that is not present in PNe. This dust component has already been invoked to explain the depletion of oxygen in molecular clouds and in the diffuse ISM.

  17. Top consumer abundance influences lake methane efflux.

    PubMed

    Devlin, Shawn P; Saarenheimo, Jatta; Syväranta, Jari; Jones, Roger I

    2015-11-04

    Lakes are important habitats for biogeochemical cycling of carbon. The organization and structure of aquatic communities influences the biogeochemical interactions between lakes and the atmosphere. Understanding how trophic structure regulates ecosystem functions and influences greenhouse gas efflux from lakes is critical to understanding global carbon cycling and climate change. With a whole-lake experiment in which a previously fishless lake was divided into two treatment basins where fish abundance was manipulated, we show how a trophic cascade from fish to microbes affects methane efflux to the atmosphere. Here, fish exert high grazing pressure and remove nearly all zooplankton. This reduction in zooplankton density increases the abundance of methanotrophic bacteria, which in turn reduce CH4 efflux rates by roughly 10 times. Given that globally there are millions of lakes emitting methane, an important greenhouse gas, our findings that aquatic trophic interactions significantly influence the biogeochemical cycle of methane has important implications.

  18. Chemical abundances in nearby spiral galaxies

    NASA Astrophysics Data System (ADS)

    Richer, Michael Gerard

    2015-08-01

    The chemical abundances observed in planetary nebulae in the discs of spiral galaxies are revealing a rich variety of information about their progenitor stars as well as the structure and evolution of the galaxies they inhabit. As concerns galaxy structure and evolution, most of the attention has been on whether gradients in chemical abundances have changed with time, but there is also the issue of the formation and origin of the stellar progenitors of planetary nebulae. The gradients in oxygen abundances for planetary nebulae in M81 and NGC 300 are shallower than the corresponding gradients for H II regions in these galaxies. On the other hand, the gradients for H II regions and planetary nebulae are similar in M33. In the case of M31, there is mounting evidence whose simplest explanation may not be related to internal processes, but instead may lay in the gravitational interaction between it and its neighbours, past and present. As concerns the nucleosynthesis of the stellar progenitors of these planetary nebulae, some results for both nitrogen and oxygen may indicate the production of these elements during the previous evolutionary stages of their progenitor stars. Nominally, this may not be surprising for nitrogen, but the results do not agree quantitatively with canonical theory. At this point, though, there are still too few studies to draw very firm conclusions regrading any of these topics. Even so, the surprises among the results found so far make clear that interpreting the chemical abundances in the planetary nebulae in nearby spirals will require considering the processes affecting both stellar and galactic evolution.

  19. Globular Clusters: Chemical Abundance - Integrated Colour calibration

    NASA Astrophysics Data System (ADS)

    Moyano Loyola, G.; Faifer, F. R.; Forte, J. C.

    In this work, we improve the chemical abundance - integrated colour cali- bration presented in Forte, Faifer & Geisler, 2007 (FFG07 hereafter) using a new (g-i) vs. (C-T1) colours calibration obtained from M87. Using this calibration and better values of the reddening for the galactic globulars, we found that a quadratic calibration is still enough to represent the observa- tional data, as in FFG07.

  20. Helium isotopic abundance variation in nature

    SciTech Connect

    Holden, N.E.

    1993-08-01

    The isotopic abundance of helium in nature has been reviewed. This atomic weight value is based on the value of helium in the atmosphere, which is invariant around the world and up to a distance of 100,000 feet. Helium does vary in natural gas, volcanic rocks and gases, ocean floor sediments, waters of various types and in radioactive minerals and ores due to {alpha} particle decay of radioactive nuclides.

  1. The Abundance of Sulfur in Venus Magmas

    NASA Astrophysics Data System (ADS)

    Bullock, M. A.; Grinspoon, D. H.

    1999-09-01

    Outgassing of sulfur gases due to volcanism within the past 100 My on Venus is probably responsible for the planet's globally encircling H2SO4 cloud layers. Dramatic changes in volcanic output on Venus would have altered the atmospheric inventory of sulfur gases, and hence the structure of its clouds (Bullock and Grinspoon, Icarus, submitted 1999). Although Magellan radar images provide some constraints on the magnitude of volcanism in the geologically recent past, little is known of the sulfur content of Venus lavas. In order to assess the effects that Venus' volcanic history may have had on cloud and therefore climate change, it is desirable to place some constraints on the abundance of sulfur in Venus magmas. The sulfur content of terrestrial volcanic lavas varies widely, depending upon the local sedimentary environment and the source and history of upwelling magmas. We estimate the average abundance of sulfur in Venus lavas from an analysis of the production and loss of atmospheric SO2. The volumetric rate of resurfacing on Venus in the recent past is approximately 0.1 to 2 km3/yr (Bullock et al., JGR 20, 1993, Basilevsky and Head, GRL 23, 1996). Outgassed SO2 reacts quickly with crustal carbonate -- residence times in the atmosphere with respect to the reaction SO2 + CaCO3 <=> CaSO4 + CO are about 2-30 My (Fegley and Prinn, Nature 337, 1989, Bullock and Grinspoon, Icarus, submitted 1999). Assuming steady state conditions and an abundance of 25-180 ppm of atmospheric SO2 (Oyama et al., JGR 85, 1980, Bertaux et al., JGR 101, 1996), we will discuss constraints on the abundance of this important greenhouse and cloud-precursor gas in Venus lavas.

  2. Revised Thorium Abundances for Lunar Red Spots

    NASA Technical Reports Server (NTRS)

    Hagerty, J. J.; Lawrence, D. J.; Elphic, R. C.; Feldman, W. C.; Vaniman, D. T.; Hawke, B. R.

    2005-01-01

    Lunar red spots are features on the nearside of the Moon that are characterized by high albedo and by a strong absorption in the ultraviolet. These red spots include the Gruithuisen domes, the Mairan domes, Hansteen Alpha, the southern portion of Montes Riphaeus, Darney Chi and Tau, Helmet, and an area near the Lassell crater. It has been suggested that many of the red spots are extrusive, nonmare, volcanic features that could be composed of an evolved lithlogy enriched in thorium. In fact, Hawke et al. used morphological characteristics to show that Hansteen Alpha is a nonmare volcanic construct. However, because the apparent Th abundances (6 - 7 ppm) were lower than that expected for evolved rock types, Hawke et al. concluded that Hansteen Alpha was composed of an unknown rock type. Subsequent studies by Lawrence et al. used improved knowledge of the Th spatial distribution for small area features on the lunar surface to revisit the interpretation of Th abundances at the Hansteen Alpha red spot. As part of their study, Lawrence et al. used a forward modeling technique to show that the Th abundance at Hansteen Alpha is not 6 ppm, but is more likely closer to 25 ppm, a value consistent with evolved lithologies. This positive correlation between the morphology and composition of Hansteen Alpha provides support for the presence of evolved lithologies on the lunar surface. It is possible, however, that Hansteen Alpha represents an isolated occurrence of non-mare volcanism. That is why we have chosen to use the forward modeling technique of Lawrence et al. to investigate the Th abundances at other lunar red spots, starting with the Gruithuisen domes. Additional information is included in the original extended abstract.

  3. Angel lichen moth abundance and morphology data

    USGS Publications Warehouse

    Metcalfe, Anya; Kennedy, Theodore A.; Muehlbauer, Jeffrey D.

    2016-01-01

    Two unique datasets on the abundance and morphology of the angel lichen moth ( Cisthene angelus) in Grand Canyon, Arizona, USA were compiled to describe the phenology and life history of this common, but poorly known, species. The abundance data were collected from 2012 to 2013 through a collaboration with river runners in Grand Canyon National Park. These citizen scientists deployed light traps from their campsites for one hour each night of their expedition. Insects were preserved in ethanol on site, and returned to the Southwest Biological Science Center in Flagstaff, Arizona for analysis in the laboratory. A total of 2,437 light trap samples were sorted through, 903 of which contained C. angelus. In total, 73,841 C. angelus were identified and enumerated to create the abundance data set. The morphology dataset is based on a subset of 28 light trap samples from sampling year 2012 (14 from spring and 14 from fall.) It includes gender and forewing lengths for 2,674 individual moths and dry weights for 1,102 of those individuals.

  4. Absolute Quantification of Endogenous Ras Isoform Abundance

    PubMed Central

    Mageean, Craig J.; Griffiths, John R.; Smith, Duncan L.; Clague, Michael J.; Prior, Ian A.

    2015-01-01

    Ras proteins are important signalling hubs situated near the top of networks controlling cell proliferation, differentiation and survival. Three almost identical isoforms, HRAS, KRAS and NRAS, are ubiquitously expressed yet have differing biological and oncogenic properties. In order to help understand the relative biological contributions of each isoform we have optimised a quantitative proteomics method for accurately measuring Ras isoform protein copy number per cell. The use of isotopic protein standards together with selected reaction monitoring for diagnostic peptides is sensitive, robust and suitable for application to sub-milligram quantities of lysates. We find that in a panel of isogenic SW48 colorectal cancer cells, endogenous Ras proteins are highly abundant with ≥260,000 total Ras protein copies per cell and the rank order of isoform abundance is KRAS>NRAS≥HRAS. A subset of oncogenic KRAS mutants exhibit increased total cellular Ras abundance and altered the ratio of mutant versus wild type KRAS protein. These data and methodology are significant because Ras protein copy number is required to parameterise models of signalling networks and informs interpretation of isoform-specific Ras functional data. PMID:26560143

  5. The shape of terrestrial abundance distributions.

    PubMed

    Alroy, John

    2015-09-01

    Ecologists widely accept that the distribution of abundances in most communities is fairly flat but heavily dominated by a few species. The reason for this is that species abundances are thought to follow certain theoretical distributions that predict such a pattern. However, previous studies have focused on either a few theoretical distributions or a few empirical distributions. I illustrate abundance patterns in 1055 samples of trees, bats, small terrestrial mammals, birds, lizards, frogs, ants, dung beetles, butterflies, and odonates. Five existing theoretical distributions make inaccurate predictions about the frequencies of the most common species and of the average species, and most of them fit the overall patterns poorly, according to the maximum likelihood-related Kullback-Leibler divergence statistic. Instead, the data support a low-dominance distribution here called the "double geometric." Depending on the value of its two governing parameters, it may resemble either the geometric series distribution or the lognormal series distribution. However, unlike any other model, it assumes both that richness is finite and that species compete unequally for resources in a two-dimensional niche landscape, which implies that niche breadths are variable and that trait distributions are neither arrayed along a single dimension nor randomly associated. The hypothesis that niche space is multidimensional helps to explain how numerous species can coexist despite interacting strongly.

  6. A global database of ant species abundances

    USGS Publications Warehouse

    Gibb, Heloise; Dunn, Rob R.; Sanders, Nathan J.; Grossman, Blair F.; Photakis, Manoli; Abril, Silvia; Agosti, Donat; Andersen, Alan N.; Angulo, Elena; Armbrecht, Ingre; Arnan, Xavier; Baccaro, Fabricio B.; Bishop, Tom R.; Boulay, Raphael; Bruhl, Carsten; Castracani, Cristina; Cerda, Xim; Del Toro, Israel; Delsinne, Thibaut; Diaz, Mireia; Donoso, David A.; Ellison, Aaron M.; Enriquez, Martha L.; Fayle, Tom M.; Feener Jr., Donald H.; Fisher, Brian L.; Fisher, Robert N.; Fitpatrick, Matthew C.; Gomez, Cristanto; Gotelli, Nicholas J.; Gove, Aaron; Grasso, Donato A.; Groc, Sarah; Guenard, Benoit; Gunawardene, Nihara; Heterick, Brian; Hoffmann, Benjamin; Janda, Milan; Jenkins, Clinton; Kaspari, Michael; Klimes, Petr; Lach, Lori; Laeger, Thomas; Lattke, John; Leponce, Maurice; Lessard, Jean-Philippe; Longino, John; Lucky, Andrea; Luke, Sarah H.; Majer, Jonathan; McGlynn, Terrence P.; Menke, Sean; Mezger, Dirk; Mori, Alessandra; Moses, Jimmy; Munyai, Thinandavha Caswell; Pacheco, Renata; Paknia, Omid; Pearce-Duvet, Jessica; Pfeiffer, Martin; Philpott, Stacy M.; Resasco, Julian; Retana, Javier; Silva, Rogerio R.; Sorger, Magdalena D.; Souza, Jorge; Suarez, Andrew V.; Tista, Melanie; Vasconcelos, Heraldo L.; Vonshak, Merav; Weiser, Michael D.; Yates, Michelle; Parr, Catherine L.

    2017-01-01

    What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51,388 ant abundance and occurrence records of more than 2693 species and 7953 morphospecies from local assemblages collected at 4212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type and degree of disturbance. The aim of compiling this dataset was to provide comprehensive species abundance data in order to test relationships between assemblage structure and environmental and biogeographic factors. Data were collected using a variety of standardised methods, such as pitfall and Winkler traps, and will be valuable for studies investigating large-scale forces structuring local assemblages. Understanding such relationships is particularly critical under current rates of global change. We encourage authors holding additional data on systematically collected ant assemblages, especially those in dry and cold, and remote areas, to contact us and contribute their data to this growing dataset.

  7. Elemental abundances of solar sibling candidates

    SciTech Connect

    Ramírez, I.; Lambert, D. L.; Endl, M.; Cochran, W. D.; MacQueen, P. J.; Bajkova, A. T.; Bobylev, V. V.; Wittenmyer, R. A.

    2014-06-01

    Dynamical information along with survey data on metallicity and in some cases age have been used recently by some authors to search for candidates of stars that were born in the cluster where the Sun formed. We have acquired high-resolution, high signal-to-noise ratio spectra for 30 of these objects to determine, using detailed elemental abundance analysis, if they could be true solar siblings. Only two of the candidates are found to have solar chemical composition. Updated modeling of the stars' past orbits in a realistic Galactic potential reveals that one of them, HD 162826, satisfies both chemical and dynamical conditions for being a sibling of the Sun. Measurements of rare-element abundances for this star further confirm its solar composition, with the only possible exception of Sm. Analysis of long-term high-precision radial velocity data rules out the presence of hot Jupiters and confirms that this star is not in a binary system. We find that chemical tagging does not necessarily benefit from studying as many elements as possible but instead from identifying and carefully measuring the abundances of those elements that show large star-to-star scatter at a given metallicity. Future searches employing data products from ongoing massive astrometric and spectroscopic surveys can be optimized by acknowledging this fact.

  8. Distribution and Abundance of Mars' Atmospheric Argon

    NASA Technical Reports Server (NTRS)

    Sprague, A. L.; Boynton, W. V.; Kerry, K. E.; Nelli, Steven; Murphy, Jim; Reedy, R. C.; Metzger, A. E.; Hunten, D. M.; Janes, K. D.; Crombie, M. K.

    2005-01-01

    One and one half Mars years (MY 26 and 27) of atmospheric Argon measurements are described and studied in the context of understanding how Argon, a minor constituent of Mars atmosphere that does not condense at Mars temperatures, can be used to study martian circulation and dynamics. Argon data are from the 2001 Mars Odyssey Gamma Subsystem (GS) of the suite of three instruments comprising the Gamma Ray Spectrometer (GRS). A comprehensive data analysis including gamma-ray production and attenuation by the atmosphere is included. Of particular interest is the enhanced abundance of Ar over the observed Ar abundance at lower latitudes at south (up to a factor of 10) and north (up to a factor of 4) polar regions during winter. Calibration of the measurements to actual Ar abundance is possible because GS measurements cover the same latitude and season as measurements made by the gas chromatograph mass spectrometer (GCMS) on Viking Landers 1 and 2 (VL1 and VL2). [2].

  9. A global database of ant species abundances.

    PubMed

    Gibb, Heloise; Dunn, Rob R; Sanders, Nathan J; Grossman, Blair F; Photakis, Manoli; Abril, Silvia; Agosti, Donat; Andersen, Alan N; Angulo, Elena; Armbrecht, Inge; Arnan, Xavier; Baccaro, Fabricio B; Bishop, Tom R; Boulay, Raphaël; Brühl, Carsten; Castracani, Cristina; Cerda, Xim; Del Toro, Israel; Delsinne, Thibaut; Diaz, Mireia; Donoso, David A; Ellison, Aaron M; Enriquez, Martha L; Fayle, Tom M; Feener, Donald H; Fisher, Brian L; Fisher, Robert N; Fitzpatrick, Matthew C; Gómez, Crisanto; Gotelli, Nicholas J; Gove, Aaron; Grasso, Donato A; Groc, Sarah; Guenard, Benoit; Gunawardene, Nihara; Heterick, Brian; Hoffmann, Benjamin; Janda, Milan; Jenkins, Clinton; Kaspari, Michael; Klimes, Petr; Lach, Lori; Laeger, Thomas; Lattke, John; Leponce, Maurice; Lessard, Jean-Philippe; Longino, John; Lucky, Andrea; Luke, Sarah H; Majer, Jonathan; McGlynn, Terrence P; Menke, Sean; Mezger, Dirk; Mori, Alessandra; Moses, Jimmy; Munyai, Thinandavha Caswell; Pacheco, Renata; Paknia, Omid; Pearce-Duvet, Jessica; Pfeiffer, Martin; Philpott, Stacy M; Resasco, Julian; Retana, Javier; Silva, Rogerio R; Sorger, Magdalena D; Souza, Jorge; Suarez, Andrew; Tista, Melanie; Vasconcelos, Heraldo L; Vonshak, Merav; Weiser, Michael D; Yates, Michelle; Parr, Catherine L

    2017-03-01

    What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51 ,388 ant abundance and occurrence records of more than 2,693 species and 7,953 morphospecies from local assemblages collected at 4,212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type, and degree of disturbance. The aim of compiling this data set was to provide comprehensive species abundance data in order to test relationships between assemblage structure and environmental and biogeographic factors. Data were collected using a variety of standardized methods, such as pitfall and Winkler traps, and will be valuable for studies investigating large-scale forces structuring local assemblages. Understanding such relationships is particularly critical under current rates of global change. We encourage authors holding additional data on systematically collected ant assemblages, especially those in dry and cold, and remote areas, to contact us and contribute their data to this growing data set.

  10. The shape of terrestrial abundance distributions

    PubMed Central

    Alroy, John

    2015-01-01

    Ecologists widely accept that the distribution of abundances in most communities is fairly flat but heavily dominated by a few species. The reason for this is that species abundances are thought to follow certain theoretical distributions that predict such a pattern. However, previous studies have focused on either a few theoretical distributions or a few empirical distributions. I illustrate abundance patterns in 1055 samples of trees, bats, small terrestrial mammals, birds, lizards, frogs, ants, dung beetles, butterflies, and odonates. Five existing theoretical distributions make inaccurate predictions about the frequencies of the most common species and of the average species, and most of them fit the overall patterns poorly, according to the maximum likelihood–related Kullback-Leibler divergence statistic. Instead, the data support a low-dominance distribution here called the “double geometric.” Depending on the value of its two governing parameters, it may resemble either the geometric series distribution or the lognormal series distribution. However, unlike any other model, it assumes both that richness is finite and that species compete unequally for resources in a two-dimensional niche landscape, which implies that niche breadths are variable and that trait distributions are neither arrayed along a single dimension nor randomly associated. The hypothesis that niche space is multidimensional helps to explain how numerous species can coexist despite interacting strongly. PMID:26601249

  11. The primordial helium abundance from updated emissivities

    SciTech Connect

    Aver, Erik; Olive, Keith A.; Skillman, Evan D.; Porter, R.L. E-mail: olive@umn.edu E-mail: skillman@astro.umn.edu

    2013-11-01

    Observations of metal-poor extragalactic H II regions allow the determination of the primordial helium abundance, Y{sub p}. The He I emissivities are the foundation of the model of the H II region's emission. Porter, Ferland, Storey, and Detisch (2012) have recently published updated He I emissivities based on improved photoionization cross-sections. We incorporate these new atomic data and update our recent Markov Chain Monte Carlo analysis of the dataset published by Izotov, Thuan, and Stasi'nska (2007). As before, cuts are made to promote quality and reliability, and only solutions which fit the data within 95% confidence level are used to determine the primordial He abundance. The previously qualifying dataset is almost entirely retained and with strong concordance between the physical parameters. Overall, an upward bias from the new emissivities leads to a decrease in Y{sub p}. In addition, we find a general trend to larger uncertainties in individual objects (due to changes in the emissivities) and an increased variance (due to additional objects included). From a regression to zero metallicity, we determine Y{sub p} = 0.2465 ± 0.0097, in good agreement with the BBN result, Y{sub p} = 0.2485 ± 0.0002, based on the Planck determination of the baryon density. In the future, a better understanding of why a large fraction of spectra are not well fit by the model will be crucial to achieving an increase in the precision of the primordial helium abundance determination.

  12. Fluorine Abundances in the Milky Way Bulge

    NASA Astrophysics Data System (ADS)

    Cunha, Katia; Smith, Verne V.; Gibson, Brad K.

    2008-05-01

    Fluorine (19F) abundances are derived in a sample of six bulge red giants in Baade's window. These giants span a factor of 10 in metallicity, and this is the first study to define the behavior of 19F with metallicity in the bulge. The bulge results show an increase in F/O with increasing oxygen. This trend overlaps what is found in the disk at comparable metallicities, with the most oxygen-rich bulge target extending the disk trend. The increase in F/O in the disk arises from 19F synthesis in both asymptotic giant branch (AGB) stars and metal-rich Wolf-Rayet (WR) stars through stellar winds. The lack of an s-process enhancement in the most fluorine-rich bulge giant in this study suggests that WR stars represented a larger contribution than did AGB stars to 19F production in the bulge, when compared to the disk. If this result for fluorine is combined with the previously published overall decline in the O/Mg abundance ratios in metal-rich bulge stars, it suggests that WR winds played a role in shaping chemical evolution in the bulge. One star in this study exhibits a very low value of F/O while having a large O abundance; this chemical mixture can be understood if this star formed from gas that was enriched by metal-poor core-collapse supernovae, and it may indicate that chemical evolution in the bulge was inhomogeneous.

  13. Elemental Abundances of Solar Sibling Candidates

    NASA Astrophysics Data System (ADS)

    Ramírez, I.; Bajkova, A. T.; Bobylev, V. V.; Roederer, I. U.; Lambert, D. L.; Endl, M.; Cochran, W. D.; MacQueen, P. J.; Wittenmyer, R. A.

    2014-06-01

    Dynamical information along with survey data on metallicity and in some cases age have been used recently by some authors to search for candidates of stars that were born in the cluster where the Sun formed. We have acquired high-resolution, high signal-to-noise ratio spectra for 30 of these objects to determine, using detailed elemental abundance analysis, if they could be true solar siblings. Only two of the candidates are found to have solar chemical composition. Updated modeling of the stars' past orbits in a realistic Galactic potential reveals that one of them, HD 162826, satisfies both chemical and dynamical conditions for being a sibling of the Sun. Measurements of rare-element abundances for this star further confirm its solar composition, with the only possible exception of Sm. Analysis of long-term high-precision radial velocity data rules out the presence of hot Jupiters and confirms that this star is not in a binary system. We find that chemical tagging does not necessarily benefit from studying as many elements as possible but instead from identifying and carefully measuring the abundances of those elements that show large star-to-star scatter at a given metallicity. Future searches employing data products from ongoing massive astrometric and spectroscopic surveys can be optimized by acknowledging this fact.

  14. Determining Evapotranspiration with the Eddy Covariance Method: Fast-Response Dry- and Wet-Bulb Thermocouples for Humidity Measurements Can Provide a Cheap Alternative to Infrared Hygrometers.

    NASA Astrophysics Data System (ADS)

    Holwerda, F.; Alvarado-Barrientos, M. S.

    2014-12-01

    Field data on evapotranspiration are of crucial importance for ecohydrological and hydrometeorological studies in the tropics. Probably the most direct way to measure evapotranspiration is with the eddy covariance method, in which the latent heat flux (λE) is calculated from turbulent fluctuations of vertical wind velocity and humidity. The humidity fluctuations are typically measured with some type of fast-response infrared hygrometer. However, these sensors are expensive, which can be problematic if research budgets are limited. Turbulent fluctuations of humidity can also be measured with fast-response dry- and wet-bulb thermocouples, which can be constructed easily and at a fraction of the price of infrared sensors. The idea of using dry- and wet-bulb thermocouples for measuring λE with the eddy covariance method is not new, but hasn't been tested recently, possibly because experiments in the late seventies showed that this approach is not without problems due to the slow response of the wet-bulb thermocouple. In the present study, values of λE derived from dry- and wet-bulb thermocouple measurements were compared with those obtained using a fast-response KH20 hygrometer. Measurements were made above a shaded coffee plantation and a sugarcane crop in central Veracruz, Mexico. The agreement between λE obtained with the thermocouples (y) and the hygrometer (x) was very good for both vegetation covers: y = 0.98x + 5.0 (W m-2), r2 = 0.93 (coffee plantation); y = 0.99x - 13.3 (W m-2), r2 = 0.88 (sugarcane). However, the correction factor (CF) for high frequency loss in the wet-bulb temperature signal was considerably higher for the low-statured sugarcane crop (CF = 1.33) as compared to the taller shaded coffee plantation (CF = 1.09). Nevertheless, as long as care is taken in the derivation of this correction factor, reliable λE data can be obtained using the dry- and wet-bulb thermocouples, offering a cheap alternative to infrared hygrometers.

  15. A pilot study on the content and the release of Ni and other allergenic metals from cheap earrings available on the Italian market.

    PubMed

    Bocca, B; Forte, G; Senofonte, O; Violante, N; Paoletti, L; De Berardis, B; Petrucci, F; Cristaudo, A

    2007-12-15

    The capability of alloys used in cheap jewellery to release metal ions on contact with the skin causing allergic contact dermatitis (ACD) is generally acknowledged. To reduce the diffusion of the Ni-induced ACD the Council Directive 94/27/EC [Council Directive 94/27/EC of 30 June 1994. Official Journal L 188, 22/07/1994, 1.] limited the total Ni content in alloys and its release rate in artificial sweat. In this work, three different aspects were explored: i) the frequency of skin sensitization to Ni-containing earrings in patients before and after the introduction of the Directive's limit; ii) metal composition of alloys by X-ray analysis; iii) metal leaching in artificial sweat followed by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) quantification. Well-known allergenic metals, as Ni, Cr and Co, and possible emergent allergens, as Al, Ag, Au, Cd, Cu, Fe, Ir, Mn, Pb, Pd, Pt, Rh, Sn, V and Zn, were studied. Results showed that the frequency of allergy due to earrings did not decrease after the introduction of the Ni limit: in 1994 and in 2005 patients positive to Ni patch tests were 54.3% and 53.5%, respectively. The earring components analyzed were Fe-based or alloys of Cu/Zn or Fe/Cr/Ni, plated with a thin film of precious metal (Ag, Au) which, in several cases, was combined with a Ni layer beneath. Five out of 10 items were not in compliance with the Ni Directive 94/27/EC having a total Ni content >0.05%. In three cases the release of Ni concentrations was higher than the safe sensitizing limit given by the above mentioned Regulation (i.e., <0.5 microg/cm(2)/week). The release of Cu and Zn was very variable among the different pieces (Cu: 0.134-30.9 microg/cm(2)/week; Zn: 0.141-160 microg/cm(2)/week); two objects released high amounts of Fe (358 and 586 microg/cm(2)/week) and one released considerable Mn (21 microg/cm(2)/week). Lead was released from 70% of the objects, while Ag, Al, Cd, Co, Cr and Sn from ca. 30% of the items and

  16. Abundances from solar-flare gamma-ray line spectroscopy

    NASA Technical Reports Server (NTRS)

    Murphy, R. J.; Ramaty, R.; Forrest, D. J.; Kozlovsky, B.

    1985-01-01

    Elemental abundances of the ambient gas at the site of gamma ray line production inthe solar atmosphere are deduced using gamma ray line observations from a solar flare. The resultant abundances are different from local galactic abundances which are thought to be similar to photospheric abundances.

  17. Climate Action Benefits: Electricity

    EPA Pesticide Factsheets

    This page provides background on the relationship between electricity and climate change and describes what the CIRA Electricity analyses cover. It provides links to the subsectors Electricity Demand and Electricity Supply.

  18. Electrical receptacle

    DOEpatents

    Leong, R.

    1993-06-22

    The invention is a receptacle for a three prong electrical plug which has either a tubular or U-shaped grounding prong. The inventive receptacle has a grounding prong socket which is sufficiently spacious to prevent the socket from significantly stretching when a larger, U-shaped grounding prong is inserted into the socket, and having two ridges to allow a snug fit when a smaller tubular shape grounding prong is inserted into the socket. The two ridges are made to prevent the socket from expanding when either the U-shaped grounding prong or the tubular grounding prong is inserted.

  19. Electrical receptacle

    DOEpatents

    Leong, Robert

    1993-01-01

    The invention is a receptacle for a three prong electrical plug which has either a tubular or U-shaped grounding prong. The inventive receptacle has a grounding prong socket which is sufficiently spacious to prevent the socket from significantly stretching when a larger, U-shaped grounding prong is inserted into the socket, and having two ridges to allow a snug fit when a smaller tubular shape grounding prong is inserted into the socket. The two ridges are made to prevent the socket from expanding when either the U-shaped grounding prong or the tubular grounding prong is inserted.

  20. Solar Electricity

    NASA Technical Reports Server (NTRS)

    1988-01-01

    ARCO Solar manufactures PV Systems tailored to a broad variety of applications. PV arrays are routinely used at remote communications installations to operate large microwave repeaters, TV and radio repeaters rural telephone, and small telemetry systems that monitor environmental conditions. Also used to power agricultural water pumping systems, to provide electricity for isolated villages and medical clinics, for corrosion protection for pipelines and bridges, to power railroad signals, air/sea navigational aids, and for many types of military systems. ARCO is now moving into large scale generation for utilities.

  1. Abundant Solar Nebula Solids in Comets

    NASA Technical Reports Server (NTRS)

    Messenger, S.; Keller, L. P.; Nakamura-Messenger, K.; Nguyen, A. N.; Clemett, S.

    2016-01-01

    Comets have been proposed to consist of unprocessed interstellar materials together with a variable amount of thermally annealed interstellar grains. Recent studies of cometary solids in the laboratory have shown that comets instead consist of a wide range of materials from across the protoplanetary disk, in addition to a minor complement of interstellar materials. These advances were made possible by the return of direct samples of comet 81P/Wild 2 coma dust by the NASA Stardust mission and recent advances in microscale analytical techniques. Isotopic studies of 'cometary' chondritic porous interplanetary dust particles (CP-IDPs) and comet 81P/Wild 2 Stardust samples show that preserved interstellar materials are more abundant in comets than in any class of meteorite. Identified interstellar materials include sub-micron-sized presolar silicates, oxides, and SiC dust grains and some fraction of the organic material that binds the samples together. Presolar grain abundances reach 1 weight percentage in the most stardust-rich CP-IDPs, 50 times greater than in meteorites. Yet, order of magnitude variations in presolar grain abundances among CP-IDPs suggest cometary solids experienced significant variations in the degree of processing in the solar nebula. Comets contain a surprisingly high abundance of nebular solids formed or altered at high temperatures. Comet 81P/Wild 2 samples include 10-40 micron-sized, refractory Ca- Al-rich inclusion (CAI)-, chondrule-, and ameboid olivine aggregate (AOA)-like materials. The O isotopic compositions of these refractory materials are remarkably similar to their meteoritic counterparts, ranging from 5 percent enrichments in (sup 16) O to near-terrestrial values. Comet 81P/Wild 2 and CP-IDPs also contain abundant Mg-Fe crystalline and amorphous silicates whose O isotopic compositions are also consistent with Solar System origins. Unlike meteorites, that are dominated by locally-produced materials, comets appear to be composed of

  2. Abundances in Blue Compact Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Dewolfe, O. M.; Salzer, J. J.

    1994-12-01

    The nebular abundances in dwarf galaxies provide valuable clues to their star-formation histories. We have been engaged in an extensive observational study of actively star-forming blue compact dwarf galaxies (BCDs). Our program combines optical and NIR imaging, optical spectroscopy, and HI and CO radio data in an attempt to understand the status of star-formation and chemical evolution in these systems. Luminosities of the BCDs in our sample lie in the range M_B = -13 -- -16. We have obtained high-quality optical spectra of 21 BCDs for the purpose of deriving nebular abundances. We present values for the abundances of He, N, O, S, Ne, and Ar for this sample. In addition, we have estimated O and N abundances for a sample of 7 non-dwarf starburst galaxies of higher luminosity. For the BCD sample, we find that the N/O ratio remains constant at a mean value of 0.032 +/- 0.004 with increasing O/H. This result, which extends over a factor of more than 10 in O/H, is indicative of the N being chiefly of primary origin in these systems. The value of N/O is observed to increase in the sample of larger starburst galaxies for log(O/H) above -3.5, consistent with previous studies. S/O and Ne/O are also both constant with increasing O/H, and have mean values of 0.032 +/- 0.007 and 0.135 +/- 0.013 respectively. The BCD and starburst O/H values were used to calibrate an abundance sequence for a number of key emission-line diagnostic ratios which allow us to estimate metallicities for a large sample of emission-line galaxies (ELGs) to an accuracy of 0.1 -- 0.2 dex. The calibrations were applied to spectral data from two large published samples of ELGs from the Michigan and Case surveys. We use these data, representing nearly 200 individual galaxies, to investigate the existence of a metallicity-luminosity relationship for actively star-forming galaxies. We find the ELGs exhibit a relationship very similar to that found for more quiescent dwarf and Magellanic irregular galaxies by

  3. Chemical abundances in early B-type stars. 5: Metal abundances and LTE/NLTE comparison

    NASA Astrophysics Data System (ADS)

    Kilian, J.

    1994-02-01

    Chemical abundances of neon, magnesium, aluminum, sulfur, and iron are derived for a sample of 21 unevolved B-stars in the local field and nearby associations. While aluminum, sulfur, and iron are underabundant in nearly all stars, near solar abundances are found for magnesium and neon. In agreement with earlier results for carbon, nitrogen, oxygen, and silicon (Kilian 1992), the present results show no correlation with surface gravities or evolutionary states, which indicates that the metal abundances reflect the original composition of the interstellar medium. The results are supplemented by a comparison of local thermodynamic equilibrium (LTE) and non-LTE (NLTE) abundances for C, N, O, Si, Mg, and Al. In most cases the differences amount to +/- (0.1-0.2) dex, which slightly exceeds the estimated accuracy of the NLTE abundance determination. However, a clear temperature gradient is evident for most elements, which indicates systematic LTE abundance errors with a maximum amplitude of 0.4 dex between 21 000 K and 31 000 K.

  4. Beryllium and Boron abundances in population II stars

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The scientific focus of this program was to undertake UV spectroscopic abundance analyses of extremely metal poor stars with attention to determining abundances of light elements such as beryllium and boron. The abundances are likely to reflect primordial abundances within the early galaxy and help to constrain models for early galactic nucleosynthesis. The general metal abundances of these stars are also important for understanding stellar evolution.

  5. Proposed Method for Estimating Health-Promoting Glucosinolates and Hydrolysis Products in Broccoli (Brassica oleracea var. italica) Using Relative Transcript Abundance.

    PubMed

    Becker, Talon M; Jeffery, Elizabeth H; Juvik, John A

    2017-01-18

    Due to the importance of glucosinolates and their hydrolysis products in human nutrition and plant defense, optimizing the content of these compounds is a frequent breeding objective for Brassica crops. Toward this goal, we investigated the feasibility of using models built from relative transcript abundance data for the prediction of glucosinolate and hydrolysis product concentrations in broccoli. We report that predictive models explaining at least 50% of the variation for a number of glucosinolates and their hydrolysis products can be built for prediction within the same season, but prediction accuracy decreased when using models built from one season's data for prediction of an opposing season. This method of phytochemical profile prediction could potentially allow for lower phytochemical phenotyping costs and larger breeding populations. This, in turn, could improve selection efficiency for phase II induction potential, a type of chemopreventive bioactivity, by allowing for the quick and relatively cheap content estimation of phytochemicals known to influence the trait.

  6. Basic Electricity. Part 2.

    ERIC Educational Resources Information Center

    Kilmer, Donald C.

    This guide, the second (part 2) in a set of four guides, is designed for the student interested in a vocation in electrical work, and includes two units: Unit IV--Electrical Theory, covering thirteen lessons (matter, the atom, electrical charges in the atom, rules of electric charges, electricity, atoms in an electrical conductor, electrical…

  7. Bringing abundance into environmental politics: Constructing a Zionist network of water abundance, immigration, and colonization.

    PubMed

    Alatout, Samer

    2009-06-01

    For more than five decades, resource scarcity has been the lead story in debates over environmental politics. More importantly, and whenever environmental politics implies conflict, resource scarcity is constructed as the culprit. Abundance of resources, if at all visited in the literature, holds less importance. Resource abundance is seen, at best, as the other side of scarcity--maybe the successful conclusion of multiple interventions that may turn scarcity into abundance. This paper reinstates abundance as a politico-environmental category in its own right. Rather than relegating abundance to a second-order environmental actor that matters only on occasion, this paper foregrounds it as a crucial element in modern environmental politics. On the substantive level, and using insights from science and technology studies, especially a slightly modified actor-network framework, I describe the emergence and consolidation of a Zionist network of abundance, immigration, and colonization in Palestine between 1918 and 1948. The essential argument here is that water abundance was constructed as fact, and became a political rallying point around which a techno-political network emerged that included a great number of elements. To name just a few, the following were enrolled in the service of such a network: geologists, geophysicists, Zionist settlement experts, Zionist organizations, political and technical categories of all sorts, Palestinians as the negated others, Palestinian revolts in search of political rights, the British Mandate authorities, the hydrological system of Palestine, and the absorptive capacity of Palestine, among others. The point was to successfully articulate these disparate elements into a network that seeks opening Palestine for Jewish immigration, redefining Palestinian geography and history through Judeo-Christian Biblical narratives, and, in the process, de-legitimizing political Palestinian presence in historic Palestine.

  8. Can occupancy-abundance models be used to monitor wolf abundance?

    PubMed

    Latham, M Cecilia; Latham, A David M; Webb, Nathan F; Mccutchen, Nicole A; Boutin, Stan

    2014-01-01

    Estimating the abundance of wild carnivores is of foremost importance for conservation and management. However, given their elusive habits, direct observations of these animals are difficult to obtain, so abundance is more commonly estimated from sign surveys or radio-marked individuals. These methods can be costly and difficult, particularly in large areas with heavy forest cover. As an alternative, recent research has suggested that wolf abundance can be estimated from occupancy-abundance curves derived from "virtual" surveys of simulated wolf track networks. Although potentially more cost-effective, the utility of this approach hinges on its robustness to violations of its assumptions. We assessed the sensitivity of the occupancy-abundance approach to four assumptions: variation in wolf movement rates, changes in pack cohesion, presence of lone wolves, and size of survey units. Our simulations showed that occupancy rates and wolf pack abundances were biased high if track surveys were conducted when wolves made long compared to short movements, wolf packs were moving as multiple hunting units as opposed to a cohesive pack, and lone wolves were moving throughout the surveyed landscape. We also found that larger survey units (400 and 576 km2) were more robust to changes in these factors than smaller survey units (36 and 144 km2). However, occupancy rates derived from large survey units rapidly reached an asymptote at 100% occupancy, suggesting that these large units are inappropriate for areas with moderate to high wolf densities (>15 wolves/1,000 km2). Virtually-derived occupancy-abundance relationships can be a useful method for monitoring wolves and other elusive wildlife if applied within certain constraints, in particular biological knowledge of the surveyed species needs to be incorporated into the design of the occupancy surveys. Further, we suggest that the applicability of this method could be extended by directly incorporating some of its assumptions into

  9. Abundance anomalies in tidal disruption events

    NASA Astrophysics Data System (ADS)

    Kochanek, C. S.

    2016-05-01

    The ˜10 per cent of tidal disruption events (TDEs) due to stars more massive than M* ≳ M⊙ should show abundance anomalies due to stellar evolution in helium, carbon and nitrogen, but not oxygen. Helium is always enhanced, but only by up to ˜25 per cent on average because it becomes inaccessible once it is sequestered in the high-density core as the star leaves the main sequence. However, portions of the debris associated with the disrupted core of a main-sequence star can be enhanced in helium by factors of 2-3 for debris at a common orbital period. These helium abundance variations may be a contributor to the observed diversity of hydrogen and helium line strengths in TDEs. A still more striking anomaly is the rapid enhancement of nitrogen and the depletion of carbon due to the CNO cycle - stars with M* ≳ M⊙ quickly show an increase in their average N/C ratio by factors of 3-10. Because low-mass stars evolve slowly and high-mass stars are rare, TDEs showing high N/C will almost all be due to ˜1-2 M⊙ stars disrupted on the main sequence. Like helium, portions of the debris will show still larger changes in C and N, and the anomalies decline as the star leaves the main sequence. The enhanced [N/C] abundance ratio of these TDEs provides the first natural explanation for the rare, nitrogen-rich quasars and may also explain the strong nitrogen emission seen in ultraviolet spectra of ASASSN-14li.

  10. Primordial Li abundance and massive particles

    SciTech Connect

    Latin-Capital-Letter-Eth apo, H.

    2012-10-20

    The problem of the observed lithium abundance coming from the Big Bang Nucleosynthesis is as of yet unsolved. One of the proposed solutions is including relic massive particles into the Big Bang Nucleosynthesis. We investigated the effects of such particles on {sup 4}HeX{sup -}+{sup 2}H{yields}{sup 6}Li+X{sup -}, where the X{sup -} is the negatively charged massive particle. We demonstrate the dominance of long-range part of the potential on the cross-section.

  11. Abundances of Planetary Nebula NGC 5315

    NASA Technical Reports Server (NTRS)

    Pottasch, S. R.; Beintema, D. A.; Koorneef, J.; Salas, J. Bernard; Feibelman, W. A.; Oegerle, William R. (Technical Monitor)

    2002-01-01

    The ISO and IUE spectra of the elliptical nebula NGC 5315 is presented. These spectra axe combined with the spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebulae is then calculated and compared to previous determinations. The HST Nicmos observations of the nebula in 3 emission lines are also presented. These observations are used to determine the helium abundance as a function of position in the nebula. A discussion is given of possible evolutionary effects.

  12. Abundances in Globular Cluster Red Giant Stars

    NASA Astrophysics Data System (ADS)

    Cavallo, R. M.

    1997-12-01

    Observations of globular cluster red giant branch (RGB) stars have shown star-to-star variations in the abundances of C, N, O, Na, Mg, and Al, contrary to predictions of standard stellar evolutionary theory. I have modeled the variations in the abundance profiles around the hydrogen-burning shell (H shell) of metal-poor red giant stars by combining four RGB stellar evolutionary sequences of different metallicities with a detailed nuclear reaction network. This approach has significant advantages over previous research: (1) it allows for the variation in the temperature and density around the H shell; (2) it follows the effects of the changing H-shell structure as the sequence evolves; (3) it accounts for the effect of the metallicity on the abundance profiles; (4) it allows the reaction rates to be varied so that their uncertainties may be explored. The results are in good qualitative agreement with the observations. All the models show a region above the H shell in which first C, then O, is depleted in the CN and ON nuclear burning cycles. Within the C-depleted region, the (12) C/(13) C ratio is reduced to its equilibrium value. Just above the O-depleted region, Na is enhanced from proton captures on (22) Ne. In brighter models, Na becomes greatly enhanced within the O-depleted region as the NeNa cycle converts (20) Ne into (23) Na before attaining equilibrium inside the H shell. The more metal-poor models also show Al being increased around the H shell, first from (25,26) Mg, then from (24) Mg in the MgAl cycle. Despite the diminution (24) Mg suffers in synthesizing Al, the models show its abundance is increased due to the NeNa-cycle breakout reaction, (23) Na(p,γ)(24) Mg. This latter result is at odds with observations that show (24) Mg is depleted in a sample of M 13 and NGC 6752 giants (Shetrone 1996, 1997).

  13. NEON AND OXYGEN ABUNDANCES AND ABUNDANCE RATIO IN THE SOLAR CORONA

    SciTech Connect

    Landi, E.; Testa, P.

    2015-02-20

    In this work we determine the Ne/O abundance ratio from Solar and Heliospheric Observatory (SOHO)/Solar Ultraviolet Measurement of Emitted Radiation (SUMER) off-disk observations of quiescent streamers over the 1996-2008 period. We find that the Ne/O ratio is approximately constant over solar cycle 23 from 1996 to 2005, at a value of 0.099 ± 0.017; this value is lower than the transition region determinations from the quiet Sun used to infer the neon photospheric abundance from the oxygen photospheric abundance. Also, the Ne/O ratio we determined from SUMER is in excellent agreement with in situ determinations from ACE/SWICS. In 2005-2008, the Ne/O abundance ratio increased with time and reached 0.25 ± 0.05, following the same trend found in the slowest wind analyzed by ACE/SWICS. Further, we measure the absolute abundance in the corona for both oxygen and neon from the data set of 1996 November 22, obtaining A {sub o} = 8.99 ± 0.04 and A {sub Ne} = 7.92 ± 0.03, and we find that both elements are affected by the first ionization potential (FIP) effect, with oxygen being enhanced by a factor of 1.4-2.1 over its photospheric abundance, and neon being changed by a factor of 0.75-1.20. We conclude that the Ne/O ratio is not constant in the solar atmosphere, both in time and at different heights, and that it cannot be reliably used to infer the neon abundance in the photosphere. Also, we argue that the FIP effect was less effective during the minimum of solar cycle 24, and that the Ne/O = 0.25 ± 0.05 value measured at that time is closer to the true photospheric value, leading to a neon photospheric abundance larger than assumed by ≈40%. We discuss the implications of these results for the solar abundance problem, for the FIP effect, and for the identification of the source regions of the solar wind.

  14. Measurements of Absolute Abundances in Solar Flares

    NASA Astrophysics Data System (ADS)

    Warren, Harry P.

    2014-05-01

    We present measurements of elemental abundances in solar flares with the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory. EVE observes both high temperature Fe emission lines (Fe XV-Fe XXIV) and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (f). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature, it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is f = 1.17 ± 0.22. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation occurs.

  15. Absolute Abundance Measurements in Solar Flares

    NASA Astrophysics Data System (ADS)

    Warren, Harry

    2014-06-01

    We present measurements of elemental abundances in solar flares with EVE/SDO and EIS/Hinode. EVE observes both high temperature Fe emission lines Fe XV-XXIV and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (F). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is F=1.17+-0.22. Furthermore, we have compared the EVE measurements with corresponding flare observations of intermediate temperature S, Ar, Ca, and Fe emission lines taken with EIS. Our initial calculations also indicate a photospheric composition for these observations. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation in the non-flaring corona occurs.

  16. Oxygen Abundances in Metal-Poor Stars

    NASA Astrophysics Data System (ADS)

    Fulbright, J. P.

    1999-05-01

    The oxygen abundances of metal-poor late-type stars can be obtained by one four methods: 1) the [O I] forbidden lines at 6300 and 6363 Angstroms, 2) the O I triplet at 7774 Angstroms, 3) OH lines at 3100-3150 Angstroms, and 4) IR CO and OH bands. Each of these methods have their strengths and weaknesses, and finding common agreement between the methods has sometimes been elusive. Recently two groups (Israelian et al, 1998, ApJ, 507, 805 and Boesgaard et al, 1999, AJ, 117, 492) have presented results from the UV OH lines and the O I triplet that suggest that the [O/Fe]-ratio continues to increase as [Fe/H] decreases. This differs from the 'traditional' result that held that [O/Fe] plateaus at +0.5 as [Fe/H] decreases. Conversely, Fulbright and Kraft (AJ, July 1999) show that in two very metal-poor stars the [O I] 6300 Angstroms line gives abundances 0.5 dex lower than obtained in the above studies. In this talk, I hope to discuss these papers and speculate on potental causes to the discrepency.

  17. MEASUREMENTS OF ABSOLUTE ABUNDANCES IN SOLAR FLARES

    SciTech Connect

    Warren, Harry P.

    2014-05-01

    We present measurements of elemental abundances in solar flares with the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory. EVE observes both high temperature Fe emission lines (Fe XV-Fe XXIV) and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (f). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature, it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is f = 1.17 ± 0.22. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation occurs.

  18. Genomic Repeat Abundances Contain Phylogenetic Signal

    PubMed Central

    Dodsworth, Steven; Chase, Mark W.; Kelly, Laura J.; Leitch, Ilia J.; Macas, Jiří; Novák, Petr; Piednoël, Mathieu; Weiss-Schneeweiss, Hanna; Leitch, Andrew R.

    2015-01-01

    A large proportion of genomic information, particularly repetitive elements, is usually ignored when researchers are using next-generation sequencing. Here we demonstrate the usefulness of this repetitive fraction in phylogenetic analyses, utilizing comparative graph-based clustering of next-generation sequence reads, which results in abundance estimates of different classes of genomic repeats. Phylogenetic trees are then inferred based on the genome-wide abundance of different repeat types treated as continuously varying characters; such repeats are scattered across chromosomes and in angiosperms can constitute a majority of nuclear genomic DNA. In six diverse examples, five angiosperms and one insect, this method provides generally well-supported relationships at interspecific and intergeneric levels that agree with results from more standard phylogenetic analyses of commonly used markers. We propose that this methodology may prove especially useful in groups where there is little genetic differentiation in standard phylogenetic markers. At the same time as providing data for phylogenetic inference, this method additionally yields a wealth of data for comparative studies of genome evolution. PMID:25261464

  19. Abundance and Distribution of Geographically Isolated ...

    EPA Pesticide Factsheets

    Geographically isolated wetlands (GIWS) are important landscape elements involved in hydrologic, biogeochemical, and biological functioning. Their influence, under certain circumstances, can significantly affect other waters of the Unites States. However, there have been no data-based estimates of the abundance of GIWs at national scales in the US, frustrating efforts to properly manage the resource. We applied a distance-based floodplain and riparian zone proxy to existing data layers from the National Hydrography Dataset (1:24,000k) and applied a geospatial buffering process to National Wetlands Inventory data to quantify the abundance of connected wetlands at significant and relevant scales. Our analyses suggest GIWs are prevalent throughout the conterminous United States, with exceptional densities in portions of the Gulf and Atlantic Coastal Plains, the Prairie Pothole Region of the Upper Midwest, and significant densities elsewhere. Indeed, over 65,000 km2 of GIWs may exist. We provide further analyses of the types, distributions, and regional extent of these systems. Lastly, we also explore additional connectivity measures associated with adjacency and relative geographic isolation to floodplains and other elements of the hydrologic landscape. Presentation at INTECOL International Wetlands Conference (Changshu, China; Sept. 2016)

  20. Fish abundance, distribution, and habitat use

    NASA Astrophysics Data System (ADS)

    Hoffnagle, Timothy L.; Valdez, Richard A.; Speas, David W.

    The 1996 controlled flood in the Colorado River, Grand Canyon, was designed, in part, to improve conditions for juvenile native fishes by reshaping habitat and displacing non-native fishes. We examined changes in abundance and distributions of native and non-native fishes immediately before and after the controlled flood and recovery of affected species 2.5 and 6 months after. Catch-per-unit-effort (CPUE) of humpback chub and flannelmouth sucker did not differ in pre- versus post-flood periods. CPUE of plains killifish, bluehead sucker and fathead minnow decreased following the flood, and CPUE of speckled dace and rainbow trout increased. Juvenile humpback chub remained primarily along talus shorelines at all discharges, while at higher discharges, speckled dace shifted from mid-channel riffles to debris fans and talus and fathead minnows used primarily vegetated shorelines. There was evidence of some downstream displacement of plains killifish, fathead minnows and rainbow trout. Catch rates of all species showed seasonal variation following the flood, with summer recruitment of young-of-the-year, particularly fathead minnows and plains killifish. Although short-term reductions in catch rates of fathead minnows and plains killifish occurred, these populations returned to pre-flood densities by 6 months after the flood. Catch rates of all species before and after the flood were similar to those recorded in previous years. We determined that the controlled flood did not significantly alter native fish distributions or abundances through Grand Canyon.

  1. Element Abundance Determination in Hot Evolved Stars

    NASA Astrophysics Data System (ADS)

    Werner, Klaus

    The hydrogen-deficiency in extremely hot post-AGB stars of spectral class PG1159 is probably caused by a (very) late helium-shell flash or a AGB final thermal pulse that consumes the hydrogen envelope, exposing the usually-hidden intershell region. Thus, the photospheric element abundances of these stars allow us to draw conclusions about details of nuclear burning and mixing processes in the precursor AGB stars. We compare predicted element abundances to those determined by quantitative spectral analyses performed with advanced non-LTE model atmospheres. A good qualitative and quantitative agreement is found for many species (He, C, N, O, Ne, F, Si, Ar) but discrepancies for others (P, S, Fe) point at shortcomings in stellar evolution models for AGB stars. Almost all of the chemical trace elements in these hot stars can only be identified in the UV spectral range. The Far Ultraviolet Spectroscopic Explorer and the Hubble Space Telescope played a crucial role for this research.

  2. Parameters and abundances in luminous stars

    SciTech Connect

    Earle Luck, R.

    2014-06-01

    Parameters and abundances for 451 stars of spectral types F, G, and K of luminosity classes I and II have been derived. Absolute magnitudes and E(B – V) have been derived for the warmer stars in order to investigate the galactic abundance gradient. The value found here: d[Fe/H]/dR ∼ –0.06 dex kpc{sup –1}, agrees well with previous determinations. Stellar evolution indicators have also been investigated with the derived C/O ratios indicating that standard CN processing has been operating. Perhaps the most surprising result found in these supposedly relatively young intermediate-mass stars is that both [O/Fe] and [C/Fe] show a correlation with [Fe/H] much the same as found in older populations. While the stars were selected based on luminosity class, there does exist a significant [Fe/H] range in the sample. The likely explanation of this is that there is a significant range in age in the sample; that is, some of the sample are low-mass red-giant stars with types that place them within the selection criteria.

  3. Occupancy as a surrogate for abundance estimation

    USGS Publications Warehouse

    MacKenzie, D.I.; Nichols, J.D.

    2004-01-01

    In many monitoring programmes it may be prohibitively expensive to estimate the actual abundance of a bird species in a defined area, particularly at large spatial scales, or where birds occur at very low densities. Often it may be appropriate to consider the proportion of area occupied by the species as an alternative state variable. However, as with abundance estimation, issues of detectability must be taken into account in order to make accurate inferences: the non?detection of the species does not imply the species is genuinely absent. Here we review some recent modelling developments that permit unbiased estimation of the proportion of area occupied, colonization and local extinction probabilities. These methods allow for unequal sampling effort and enable covariate information on sampling locations to be incorporated. We also describe how these models could be extended to incorporate information from marked individuals, which would enable finer questions of population dynamics (such as turnover rate of nest sites by specific breeding pairs) to be addressed. We believe these models may be applicable to a wide range of bird species and may be useful for investigating various questions of ecological interest. For example, with respect to habitat quality, we might predict that a species is more likely to have higher local extinction probabilities, or higher turnover rates of specific breeding pairs, in poor quality habitats.

  4. Evolutionary Dynamics of Abundant Stop Codon Readthrough

    PubMed Central

    Jungreis, Irwin; Kellis, Manolis

    2016-01-01

    Translational stop codon readthrough emerged as a major regulatory mechanism affecting hundreds of genes in animal genomes, based on recent comparative genomics and ribosomal profiling evidence, but its evolutionary properties remain unknown. Here, we leverage comparative genomic evidence across 21 Anopheles mosquitoes to systematically annotate readthrough genes in the malaria vector Anopheles gambiae, and to provide the first study of abundant readthrough evolution, by comparison with 20 Drosophila species. Using improved comparative genomics methods for detecting readthrough, we identify evolutionary signatures of conserved, functional readthrough of 353 stop codons in the malaria vector, Anopheles gambiae, and of 51 additional Drosophila melanogaster stop codons, including several cases of double and triple readthrough and of readthrough of two adjacent stop codons. We find that most differences between the readthrough repertoires of the two species arose from readthrough gain or loss in existing genes, rather than birth of new genes or gene death; that readthrough-associated RNA structures are sometimes gained or lost while readthrough persists; that readthrough is more likely to be lost at TAA and TAG stop codons; and that readthrough is under continued purifying evolutionary selection in mosquito, based on population genetic evidence. We also determine readthrough-associated gene properties that predate readthrough, and identify differences in the characteristic properties of readthrough genes between clades. We estimate more than 600 functional readthrough stop codons in mosquito and 900 in fruit fly, provide evidence of readthrough control of peroxisomal targeting, and refine the phylogenetic extent of abundant readthrough as following divergence from centipede. PMID:27604222

  5. Principal component analysis on chemical abundances spaces

    NASA Astrophysics Data System (ADS)

    Ting, Yuan-Sen; Freeman, Kenneth C.; Kobayashi, Chiaki; De Silva, Gayandhi M.; Bland-Hawthorn, Joss

    2012-04-01

    In preparation for the High Efficiency and Resolution Multi-Element Spectrograph (HERMES) chemical tagging survey of about a million Galactic FGK stars, we estimate the number of independent dimensions of the space defined by the stellar chemical element abundances [X/Fe]. This leads to a way to study the origin of elements from observed chemical abundances using principal component analysis. We explore abundances in several environments, including solar neighbourhood thin/thick disc stars, halo metal-poor stars, globular clusters, open clusters, the Large Magellanic Cloud and the Fornax dwarf spheroidal galaxy. By studying solar-neighbourhood stars, we confirm the universality of the r-process that tends to produce [neutron-capture elements/Fe] in a constant ratio. We find that, especially at low metallicity, the production of r-process elements is likely to be associated with the production of α-elements. This may support the core-collapse supernovae as the r-process site. We also verify the overabundances of light s-process elements at low metallicity, and find that the relative contribution decreases at higher metallicity, which suggests that this lighter elements primary process may be associated with massive stars. We also verify the contribution from the s-process in low-mass asymptotic giant branch (AGB) stars at high metallicity. Our analysis reveals two types of core-collapse supernovae: one produces mainly α-elements, the other produces both α-elements and Fe-peak elements with a large enhancement of heavy Fe-peak elements which may be the contribution from hypernovae. Excluding light elements that may be subject to internal mixing, K and Cu, we find that the [X/Fe] chemical abundance space in the solar neighbourhood has about six independent dimensions both at low metallicity (-3.5 ≲ [Fe/H] ≲-2) and high metallicity ([Fe/H] ≳-1). However the dimensions come from very different origins in these two cases. The extra contribution from low-mass AGB

  6. Plant abundance: the measurement and relationship with seed size

    USGS Publications Warehouse

    Guo, Q.

    2003-01-01

    There are many inconsistencies in early reports describing the relationships between plant abundance and other biotic (e.g., seed size) or abiotic variables (e.g., precipitation). It has been difficult to generalize such relationships when abundance is measured differently (e.g., density, biomass, cover). This article suggests using abundance in two broad categories: numerical abundance (e.g., number of individuals, density) and mass abundance (e.g., biomass, cover). Collective evidence indicates that when abundance is measured the same way, the observed patterns may actually be more consistent.

  7. ABUNDANCES OF GALACTIC ANTICENTER PLANETARY NEBULAE AND THE OXYGEN ABUNDANCE GRADIENT IN THE GALACTIC DISK

    SciTech Connect

    Henry, R. B. C.; Morrison, Michael A.; Kwitter, Karen B.; Jaskot, Anne E.; Balick, Bruce; Milingo, Jacquelynne B. E-mail: morrison@nhn.ou.ed E-mail: ajaskot@umich.ed E-mail: jmilingo@gettysburg.ed

    2010-11-20

    We have obtained spectrophotometric observations of 41 anticenter planetary nebulae (PNe) located in the disk of the Milky Way. Electron temperatures and densities, as well as chemical abundances for He, N, O, Ne, S, Cl, and Ar were determined. Incorporating these results into our existing database of PN abundances yielded a sample of 124 well-observed objects with homogeneously determined abundances extending from 0.9 to 21 kpc in galactocentric distance. We performed a detailed regression analysis which accounted for uncertainties in both oxygen abundances and radial distances in order to establish the metallicity gradient across the disk to be 12 + log(O/H) = (9.09 {+-} 0.05) - (0.058 {+-} 0.006) x R{sub g} , with R{sub g} in kpc. While we see some evidence that the gradient steepens at large galactocentric distances, more objects toward the anticenter need to be observed in order to confidently establish the true form of the metallicity gradient. We find no compelling evidence that the gradient differs between Peimbert Types I and II, nor is oxygen abundance related to the vertical distance from the galactic plane. Our gradient agrees well with analogous results for H II regions but is steeper than the one recently published by Stanghellini and Haywood over a similar range in galactocentric distance. A second analysis using PN distances from a different source implied a flatter gradient, and we suggest that we have reached a confusion limit which can only be resolved with greatly improved distance measurements and an understanding of the natural scatter in oxygen abundances.

  8. Atmospheric electricity

    NASA Technical Reports Server (NTRS)

    1987-01-01

    In the last three years the focus was on the information contained in the lightning measurement, which is independent of other meteorological measurements that can be made from space. The characteristics of lightning activity in mesoscale convective systems were quantified. A strong relationship was found between lightning activity and surface rainfall. It is shown that lightning provides a precursor signature for wet microbursts (the strong downdrafts that produce windshears hazardous to aircraft) and that the lightning signature is a direct consequence of storm evolution. The Universities Space Research Association (USRA) collaborated with NASA scientists in the preliminary analysis and scientific justification for the design and deployment of an optical instrument which can detect lightning from geostationary orbit. Science proposals for the NASA mesoscale science program and for the Tethered Satellite System were reviewed. The weather forecasting research and unmanned space vehicles. Software was written to ingest and analyze the lightning ground strike data on the MSFC McIDAS system. The capabilities which were developed have a wide application to a number of problems associated with the operational impacts of electrical discharge within the atmosphere.

  9. An Update of the Primordial Helium Abundance

    NASA Astrophysics Data System (ADS)

    Peimbert, Antonio; Peimbert, Manuel; Luridiana, Valentina

    2015-08-01

    Three of the best determinations of the primordial helium abundance (Yp) are those obtained from low metallicity HII regions by Aver, Olive, Porter, & Skillman (2013); Izotov, Thuan, & Guseva (2014); and Peimbert, Peimbert, & Luridiana (2007). In this poster we update the Yp determination by Peimbert et al. taking into account, among other aspects, recent advances in the determination of the He atomic physical parameters, the temperature structure, the collisional effects of high temperatures on the Balmer lines, as well as the effect of H and He bound-bound absorption.We compare our results with those of Aver et al. and Izotov et al. and point out possible explanations for the differences among the three determinations. We also compare our results with those obtained with the Plank satellite considering recent measurements of the neutron mean life; this comparison has implications on the determination of the number of light neutrino families.

  10. Subhalo Abundance Matching in f (R ) Gravity

    NASA Astrophysics Data System (ADS)

    He, Jian-hua; Li, Baojiu; Baugh, Carlton M.

    2016-11-01

    Using the liminality N -body simulations of Shi et al., we present the first predictions for galaxy clustering in f (R ) gravity using subhalo abundance matching. We find that, for a given galaxy density, even for an f (R ) model with fR 0=-10-6, for which the cold dark matter clustering is very similar to the cold dark matter model with a cosmological constant (Λ CDM ), the predicted clustering of galaxies in the f (R ) model is very different from Λ CDM . The deviation can be as large as 40% for samples with mean densities close to that of L* galaxies. This large deviation is testable given the accuracy that future large-scale galaxy surveys aim to achieve. Our result demonstrates that galaxy surveys can provide a stringent test of general relativity on cosmological scales, which is comparable to the tests from local astrophysical observations.

  11. Cosmological implications of light element abundances: theory.

    PubMed Central

    Schramm, D N

    1993-01-01

    Primordial nucleosynthesis provides (with the microwave background radiation) one of the two quantitative experimental tests of the hot Big Bang cosmological model (versus alternative explanations for the observed Hubble expansion). The standard homogeneous-isotropic calculation fits the light element abundances ranging from 1H at 76% and 4He at 24% by mass through 2H and 3He at parts in 105 down to 7Li at parts in 1010. It is also noted how the recent Large Electron Positron Collider (and Stanford Linear Collider) results on the number of neutrinos (Nnu) are a positive laboratory test of this standard Big Bang scenario. The possible alternate scenario of quark-hadron-induced inhomogeneities is also discussed. It is shown that when this alternative scenario is made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density (Omegab) remain approximately the same as in the standard homogeneous case, thus adding to the robustness of the standard model and the conclusion that Omegab approximately 0.06. This latter point is the driving force behind the need for nonbaryonic dark matter (assuming total density Omegatotal = 1) and the need for dark baryonic matter, since the density of visible matter Omegavisible < Omegab. The recent Population II B and Be observations are also discussed and shown to be a consequence of cosmic ray spallation processes rather than primordial nucleosynthesis. The light elements and Nnu successfully probe the cosmological model at times as early as 1 sec and a temperature (T) of approximately 10(10) K (approximately 1 MeV). Thus, they provided the first quantitative arguments that led to the connections of cosmology to nuclear and particle physics. Images Fig. 2 PMID:11607387

  12. Earth abundant bimetallic nanoparticles for heterogeneous catalysis

    NASA Astrophysics Data System (ADS)

    Senn, Jonathan F., Jr.

    Polymer exchange membrane fuel cells have the potential to replace current fossil fuel-based technologies in terms of emissions and efficiency, but CO contamination of H2 fuel, which is derived from steam methane reforming, leads to system inefficiency or failure. Solutions currently under development are bimetallic nanoparticles comprised of earth-abundant metals in different architectures to reduce the concentration of CO by PROX during fuel cell operation. Chapter One introduces the Pt-Sn and Co-Ni bimetallic nanoparticle systems, and the intermetallic and core-shell architectures of interest for catalytic evaluation. Application, theory, and studies associated with the efficacy of these nanoparticles are briefly reviewed. Chapter Two describes the concepts of the synthetic and characterization methods used in this work. Chapter Three presents the synthetic, characterization, and catalytic findings of this research. Pt, PtSn, PtSn2, and Pt 3Sn nanoparticles have been synthesized and supported on gamma-Al2O3. Pt3Sn was shown to be an effective PROX catalyst in various gas feed conditions, such as the gas mixture incorporating 0.1% CO, which displayed a light-off temperatures of ˜95°C. Co and Ni monometallic and CoNi bimetallic nanoparticles have been synthesized and characterized, ultimately leading to the development of target Co Ni core-shell nanoparticles. Proposed studies of catalytic properties of these nanoparticles in preferential oxidation of CO (PROX) reactions will further elucidate the effects of different crystallographic phases, nanoparticle-support interactions, and architecture on catalysis, and provide fundamental understanding of catalysis with nanoparticles composed of earth abundant metals in different architectures.

  13. Cosmological implications of light element abundances: theory.

    PubMed

    Schramm, D N

    1993-06-01

    Primordial nucleosynthesis provides (with the microwave background radiation) one of the two quantitative experimental tests of the hot Big Bang cosmological model (versus alternative explanations for the observed Hubble expansion). The standard homogeneous-isotropic calculation fits the light element abundances ranging from 1H at 76% and 4He at 24% by mass through 2H and 3He at parts in 105 down to 7Li at parts in 1010. It is also noted how the recent Large Electron Positron Collider (and Stanford Linear Collider) results on the number of neutrinos (Nnu) are a positive laboratory test of this standard Big Bang scenario. The possible alternate scenario of quark-hadron-induced inhomogeneities is also discussed. It is shown that when this alternative scenario is made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density (Omegab) remain approximately the same as in the standard homogeneous case, thus adding to the robustness of the standard model and the conclusion that Omegab approximately 0.06. This latter point is the driving force behind the need for nonbaryonic dark matter (assuming total density Omegatotal = 1) and the need for dark baryonic matter, since the density of visible matter Omegavisible < Omegab. The recent Population II B and Be observations are also discussed and shown to be a consequence of cosmic ray spallation processes rather than primordial nucleosynthesis. The light elements and Nnu successfully probe the cosmological model at times as early as 1 sec and a temperature (T) of approximately 10(10) K (approximately 1 MeV). Thus, they provided the first quantitative arguments that led to the connections of cosmology to nuclear and particle physics.

  14. Planetary nebulae near the Galactic Centre: chemical abundances

    NASA Astrophysics Data System (ADS)

    Cavichia, O.; Costa, R. D. D.; Maciel, W. J.; Mollá, M.

    2014-10-01

    In this work, we report physical parameters and abundances derived for a sample of high extinction planetary nebulae located in the Galactic bulge, near the Galactic Centre, based on low dispersion spectroscopy secured at the SOAR telescope using the Goodman spectrograph. The results show that the abundances of our sample are similar to those from other regions of the bulge. Nevertheless, the average abundances of the Galactic bulge do not follow the observed trend of the radial abundance gradient in the disk.

  15. Solar-system abundances of the elements - A new table

    NASA Technical Reports Server (NTRS)

    Grevesse, Nicolas; Anders, Edward

    1989-01-01

    This paper presents an abridged version of a new abundance compilation (Anders and Grevesse, 1988), representing an update of Anders and Ebihara (1982) and Grevesse (1984). It includes revised meteoritic abundances as well as photospheric and coronal abundances, based on literature through mid-1988.

  16. Li-7 abundances in halo stars: Testing stellar evolution models and the primordial Li-7 abundance

    NASA Technical Reports Server (NTRS)

    Chaboyer, Brian; Demarque, P.

    1994-01-01

    A large number of stellar evolution models with (Fe/H) = -2.3 and -3.3 have been calculated in order to determine the primordial Li-7 abundance and to test current stellar evolution models by a comparison to the extensive database of accurate Li abundances in extremely metal-poor halo stars observed by Thorburn (1994). Standard models with gray atmospheres do a very good job of fitting the observed Li abundances in stars hotter than approximately 5600 K. They predict a primordial. Li-7 abundance of log N(Li) = 2.24 +/- 0.03. Models which include microscopic diffusion predict a downward curvature in the Li-7 destruction isochrones at hot temperatures which is not present in the observations. Thus, the observations clearly rule out models which include uninhibited microscopic diffusion of Li-7 from the surface of the star. Rotational mixing inhibits the microscopic diffusion and the (Fe/H) = -2.28 stellar models which include both diffusion and rotational mixing provide an excellent match to the mean trend in T(sub eff) which is present in the observations. Both the plateau stars and the heavily depleted cool stars are well fit by these models. The rotational mixing leads to considerable Li-7 depletion in these models and the primordial Li-7 abundance inferred from these models is log N(Li) = 3.08 +/- 0.1. However, the (Fe/H) = -3.28 isochrones reveal problems with the combined models. These isochrones predict a trend of decreasing log N(Li) with increasing T(sub eff) which is not present in the observations. Possible causes for this discrepancy are discussed.

  17. The Electric Car Challenge.

    ERIC Educational Resources Information Center

    Diehl, Brian E.

    1997-01-01

    Describes the Electric Car Challenge during which students applied methods of construction to build lightweight, strong vehicles that were powered by electricity. The activity required problem solving, sheet metal work, electricity, design, and construction skills. (JOW)

  18. Fuel and electricity: The shifting paradigm

    SciTech Connect

    Vansant, J.

    1995-12-31

    Competition in electricity markets will fundamentally reshape fuel markets, purchasing strategies and relationships, as well as intensify the need to make gas user-friendly through standardization. Natural gas will compete on prices and be abundant in supply but will fall short on customer services with respect to ease of transactions. The need for an effective communications network in the natural gas industry is discussed.

  19. Agricultural Electricity. Electric Motors. Student Manual.

    ERIC Educational Resources Information Center

    Benson, Robert T.

    Addressed to the student, this manual, which includes supplementary diagrams, discusses the following topics and principles: Electromagnetic fields, electromagnets, parts of an electric motor, determining speed of an electric motor, types of electric motors in common use (split-phase, capacitor, repulsion-induction, three-phase), the electric…

  20. Electrical safety guidelines

    SciTech Connect

    Not Available

    1993-09-01

    The Electrical Safety Guidelines prescribes the DOE safety standards for DOE field offices or facilities involved in the use of electrical energy. It has been prepared to provide a uniform set of electrical safety standards and guidance for DOE installations in order to affect a reduction or elimination of risks associated with the use of electrical energy. The objectives of these guidelines are to enhance electrical safety awareness and mitigate electrical hazards to employees, the public, and the environment.

  1. DOE handbook electrical safety

    SciTech Connect

    1998-01-01

    Electrical Safety Handbook presents the Department of Energy (DOE) safety standards for DOE field offices or facilities involved in the use of electrical energy. It has been prepared to provide a uniform set of electrical safety guidance and information for DOE installations to effect a reduction or elimination of risks associated with the use of electrical energy. The objectives of this handbook are to enhance electrical safety awareness and mitigate electrical hazards to employees, the public, and the environment.

  2. Elemental Abundances in the Galactic Disk

    NASA Astrophysics Data System (ADS)

    Reddy, B. E.; Tomkin, J.; Lambert, D. L.; Allende Prieto, C.

    Here, we discussed our recent results of elemental abundance survey of Galactic disk based on 181 F- and G-type dwarfs (published by Reddy et al. 2003, MNRAS, 340, 304). Using high-resolution and high signal-to-noise spectra we obtained quantitative abundances for 27 elements: C, N, O, Na, Mg, Al, Si, S, K, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, Ce, Nd, and Eu. For the entire sample we have determined kinematic (U,V,W) and the orbital parameters (peri- and apo- Galactic distances). The alpha-elements -- O, Mg, Si, Ca, and Ti -- show [α/Fe] to increase slightly with decreasing [Fe/H]. Heavy elements with dominant contributions at solar metallicity from the s-process show [s/Fe] to decrease slightly with decreasing [Fe/H]. Scatter in [X/Fe] at a fixed [Fe/H] is entirely attributable to the small measurement errors, after excluding the few thick disk stars and the s-process enriched CH subgiants. Tight limits are set on `cosmic' scatter. If a weak trend with [Fe/H] is taken into account, the composition of a thin disk star expressed as [X/Fe] is independent of the star's age and birthplace for elements contributed in different proportions by massive stars (Type II SN), exploding white dwarfs (Type Ia SN), and asymptotic red giant branch stars. By combining our sample with published studies, we deduced properties of thin and thick disk stars. Thick disk stars are primarily identified by their VLSR in the range - 40 to -100 km s-1. These are very old stars with origins in the inner Galaxy and metallicities [Fe/H] <˜-0.4. At the same [Fe/H], the sampled thin disk stars have VLSR ˜0 km s-1, and are generally younger with a birthplace at about the Sun's Galactocentric distance. In the range -0.35 ≥ [Fe/H] ≥ -0.70, well represented by present thin and thick disk samples, [X/Fe] of the thick disk stars is greater than that of thin disk stars for Mg, Al, Si, Ca, Ti, and Eu. [X/Fe] is very similar for the thin and thick disk for -- notably -- Na, and iron

  3. Barium Abundances in Omega Centauri Candidate Stars

    NASA Astrophysics Data System (ADS)

    Skipper, Joy Nicole; Sobeck, Jennifer; Majewski, Steven R.; Rochford Hayes, Christian; Cunha, Katia M. L.; Smith, Verne V.; Damke, Guillermo; García Pérez, Ana; Nidever, David L.

    2017-01-01

    The "globular cluster" omega Centauri has several peculiar features that set it apart from other Milky Way globular clusters, such as its large mass, extended size, oblate shape, internal rotation, large age and metallicity spreads, and retrograde orbit. Because of these properties it is thought that Omega Cen may be a heavily stripped remnant of a Milky Way-captured dwarf spheroidal galaxy, now currently orbiting (backwards) near the Galactic plane (e.g., Lee et al. 1999, Majewski et al. 2000). A previous search within a large, all-sky low resolution spectroscopic and photometric catalog of giant stars by Majewski et al. (2012) identified candidate retrograde stars near that plane also having kinematics consistent with being stripped debris from omega Cen, based on tidal destruction models of the system. To confirm their status as omega Centauri members, high resolution spectroscopy was undertaken of a subsample of a dozen of these candidates, and most were found by Majewski et al. to exhibit very high relative Ba abundances (as measured by the 5854 transition) — a peculiar characteristic of the omega Centauri system as originally shown by Smith et al. (2000) and Norris & Da Costa (1998). Thus, these results showed the likelihood of a connection between these widely distributed field stars and omega Centauri.We have continued this spectroscopic investigation with an expanded sample of candidate tidally-stripped omega Cen giant stars. High-resolution spectra were obtained in the wavelength region (4140~6210A) with the Ultraviolet Visual Echelle Spectrograph (UVES) on the 8.0-m Very Large Telescope (VLT) for additional candidates. For these data, we have employed multiple transitions to derive reliable [Ba/Fe] ratios. We will compare these and other derived abundances to those of the omega Cen core, other globular cluster and field stars. Any additionally-confirmed omega Cen debris stars to combine with those from the previous studies will allow for a more

  4. Manganese abundances in Galactic bulge red giants

    NASA Astrophysics Data System (ADS)

    Barbuy, B.; Hill, V.; Zoccali, M.; Minniti, D.; Renzini, A.; Ortolani, S.; Gómez, A.; Trevisan, M.; Dutra, N.

    2013-11-01

    Context. Manganese is mainly produced in type II SNe during explosive silicon burning, in incomplete Si-burning regions, and depends on several nucleosynthesis environment conditions, such as mass cut between the matter ejected and falling back onto the remnant, electron and neutron excesses, mixing fallback, and explosion energy. Manganese is also produced in type Ia SNe. Aims: The aim of this work is the study of abundances of the iron-peak element Mn in 56 bulge giants, among which 13 are red clump stars. Four bulge fields along the minor axis are inspected. The study of abundances of Mn-over-Fe as a function of metallicity in the Galactic bulge may shed light on its production mechanisms. Methods: High-resolution spectra were obtained using the FLAMES+UVES spectrograph on the Very Large Telescope. The spectra were obtained within a program to observe 800 stars using the GIRAFFE spectrograph, together with the present UVES spectra. Results: We aim at identifying the chemical evolution of manganese, as a function of metallicity, in the Galactic bulge. We find [Mn/Fe] ~ -0.7 at [Fe/H] ~ -1.3, increasing to a solar value at metallicities close to solar, and showing a spread around - 0.7 ≲ [Fe/H] ≲ -0.2, in good agreement with other work on Mn in bulge stars. There is also good agreement with chemical evolution models. We find no clear difference in the behaviour of the four bulge fields. Whereas [Mn/Fe] vs. [Fe/H] could be identified with the behaviour of the thick disc stars, [Mn/O] vs. [O/H] has a behaviour running parallel, at higher metallicities, compared to thick disc stars, indicating that the bulge enrichment might have proceeded differently from that of the thick disc. Observations collected at the European Southern Observatory, Paranal, Chile (ESO programmes 71.B-0617A, 73.B0074A, and GTO 71.B-0196).Tables 1-6 and Figs. 1-6 are available in electronic form at http://www.aanda.org

  5. Chemical characterization and metal abundance in Sri Lankan serpentine soils

    NASA Astrophysics Data System (ADS)

    Vithanage, M. S.; Rajapaksha, A. U.; Ok, Y. S.; Oze, C.

    2012-12-01

    Chemical weathering of ultramafic rocks and their related soils provide localized sources of metal contamination. In Sri Lanka, rural communities live in close proximity to these rocks and soils and utilize associated groundwaters where human intake of these high metal sources may have adverse human health effects. This study investigates metal abundances and variations in Sri Lankan serpentine soils to begin evaluating potential human health hazards. Specifically, we examine serpentinite occurrences at Ussangoda, Wasgamuwa, Ginigalpelessa, and Indikolapelessa located at the geological boundary between the Highland and Vijayan Complexes. The pH of the soils are near neutral (6.26 to 7.69) with soil electrical conductivities (EC) ranging from 33.5 to 129.9 μS cm-1, a range indicative of relatively few dissolved salts and/or major dissolved inorganic solutes. The highest EC is from the Ussangoda soil which may be due to the atmospheric deposition of salt spray from the sea. Organic carbon contents of the soils range from 1.09% to 2.58%. The highest organic carbon percentage is from the Wasgamuwa soil which is located in a protected preserve. X-ray fluorescence (XRF) spectrometry and total metal digestion results show that all serpentine soils are Fe-, Cr-, and Ni-rich with abundant aluminosilicate minerals. Nickel is highest in the Ussangoda soil (6,459 mg kg-1), while Cr (>10,000 mg kg-1), Co (441 mg kg-1) and Mn (2,263 mg kg-1) are highest in the Wasgamuwa serpentine soil. Additionally, Mn (2,200 mg kg-1) and Co (400 mg kg-1) are present at high concentrations in the Wasgamuwa and Ginigalpelessa soils respectively. Electron microprobe mapping demonstrates that these heavy metals are not homogeneously distributed where Cr is specifically associated with Al and Fe phases. Metal speciation of these serpentine soils are currently being investigated using X-ray absorption spectroscopy (XAS) to provide better constraints with regards to their mobility and toxicity.

  6. Predicted correspondence between species abundances and dendrograms of niche similarities

    PubMed Central

    Sugihara, George; Bersier, Louis-Félix; Southwood, T. Richard E.; Pimm, Stuart L.; May, Robert M.

    2003-01-01

    We examine a hypothesized relationship between two descriptions of community structure: the niche-overlap dendrogram that describes the ecological similarities of species and the pattern of relative abundances. Specifically, we examine the way in which this relationship follows from the niche hierarchy model, whose fundamental assumption is a direct connection between abundances and underlying hierarchical community organization. We test three important, although correlated, predictions of the niche hierarchy model and show that they are upheld in a set of 11 communities (encompassing fishes, amphibians, lizards, and birds) where both abundances and dendrograms were reported. First, species that are highly nested in the dendrogram are on average less abundant than species from branches less subdivided. Second, and more significantly, more equitable community abundances are associated with more evenly branched dendrogram structures, whereas less equitable abundances are associated with less even dendrograms. This relationship shows that abundance patterns can give insight into less visible aspects of community organization. Third, one can recover the distribution of proportional abundances seen in assemblages containing two species by treating each branch point in the dendrogram as a two-species case. This reconstruction cannot be achieved if abundances and the dendrogram are unrelated and suggests a method for hierarchically decomposing systems. To our knowledge, this is the first test of a species abundance model based on nontrivial predictions as to the origins and causes of abundance patterns, and not simply on the goodness-of-fit of distributions. PMID:12702773

  7. Abundances in the Planetary Nebula IC 5217

    NASA Technical Reports Server (NTRS)

    Hyung, Siek; Aller, Lawrence H.; Feibelman, Walter A.; Lee, Woo-Baik; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    High resolution optical wavelength spectroscopic data were secured in the optical wavelengths, 3700A - 10,050A, for the planetary nebula IC 5217 with the Hamilton Echelle Spectrograph at Lick Observatory. These optical spectra have been analyzed along with the near-UV and UV archive data. Diagnostic analyses indicate a nebular physical condition with electron temperature of about 10,700 K (from the [O III] lines) and the density of N(sub epsilon) = 5000/cm. Ionic concentrations have been derived with the representative diagnostics, and with the aid of a photoionization model construction, we derived the elemental abundances. Contrary to the previous studies found in the literature, He and C appear to be depleted compared to the average planetary nebula and to the Sun (and S marginally so), while the remaining elements appear to be close to the average value. IC 5217 may have evolved from an O-rich progenitor and the central star temperature of IC 5217 is likely to be 92,000 K.

  8. Late Embryogenesis Abundant (LEA) proteins in legumes.

    PubMed

    Battaglia, Marina; Covarrubias, Alejandra A

    2013-01-01

    Plants are exposed to different external conditions that affect growth, development, and productivity. Water deficit is one of these adverse conditions caused by drought, salinity, and extreme temperatures. Plants have developed different responses to prevent, ameliorate or repair the damage inflicted by these stressful environments. One of these responses is the activation of a set of genes encoding a group of hydrophilic proteins that typically accumulate to high levels during seed dehydration, at the last stage of embryogenesis, hence named Late Embryogenesis Abundant (LEA) proteins. LEA proteins also accumulate in response to water limitation in vegetative tissues, and have been classified in seven groups based on their amino acid sequence similarity and on the presence of distinctive conserved motifs. These proteins are widely distributed in the plant kingdom, from ferns to angiosperms, suggesting a relevant role in the plant response to this unfavorable environmental condition. In this review, we analyzed the LEA proteins from those legumes whose complete genomes have been sequenced such as Phaseolus vulgaris, Glycine max, Medicago truncatula, Lotus japonicus, Cajanus cajan, and Cicer arietinum. Considering their distinctive motifs, LEA proteins from the different groups were identified, and their sequence analysis allowed the recognition of novel legume specific motifs. Moreover, we compile their transcript accumulation patterns based on publicly available data. In spite of the limited information on these proteins in legumes, the analysis and data compiled here confirm the high correlation between their accumulation and water deficit, reinforcing their functional relevance under this detrimental conditions.

  9. High Abundance of Ions in Cosmic Ices

    NASA Technical Reports Server (NTRS)

    Gudipati, Murthy S.; Allamandola, Louis J.; Fonda, Mark (Technical Monitor)

    2002-01-01

    Water-rich, mixed molecular ices and polycyclic aromatic hydrocarbons (PAHs) are common throughout interstellar molecular clouds and the Solar System. Vacuum ultraviolet (VUV) irradiation and particle bombardment of these abiotic ices produces complex organic species, including important biogenic molecules such as amino acids and functionalized PAHs which may have played a role in the origin of life. This ability of such water-rich, oxygen dominated ices to promote production of complex organic species is surprising and points to an important, unusual, but previously overlooked mechanism at play within the ice. Here we report the nature of this mechanism using electronic spectroscopy. VUV-irradiation of PAH/H2O ices leads to an unprecedented and efficient (greater than 70 %) conversion of the neutral PAHs to their cation form (PAH+). Further, these H2O/PAH+ ices are stabile at temperatures below 50 K, a temperature domain common throughout interstellar clouds and the Solar System. Between 50 and 125 K they react to form the complex organics. In view of this, we conclude that charged PAHs and other molecular ions should be common and abundant in many cosmic ices. The chemical, spectroscopic and physical properties of these ion-rich ices can be of fundamental importance for objects as diverse as comets, planets, and molecular clouds and may account for several poorly understood phenomena associated with each of these object classes.

  10. Detailed abundances in EMP dwarfs from SDSS

    NASA Astrophysics Data System (ADS)

    Sbordone, Luca; Caffau, Elisabetta; Bonifacio, Piercarlo

    2012-09-01

    We report on the current status of an ongoing survey to select extremely metal poor (EMP) turn-off (TO) stars from Sloan Digital Sky Survey (SDSS) spectra, and determine their detailed chemical composition through high resolution follow-up. So far, 26 stars have been observed with UVESatVLT and X-SHOOTERatVLT, all but two showing an iron content below [Fe/H]=-3. Among them we detected the current record holder for the lowest total metallicity (SDSS J102915+172927, Z=10-5 Zsolar), four carbon-enhanced extremely metal poor objects (CEMP), as well as subsets with enhanced Ni and Mn. Lithium abundances or upper limits were derived, confirming the previously detected ``meltdown'' of the Spite plateau for metallicities below about [Fe/H]=-2.8. SDSS J102915+172927 in particular shows no detectable Li I 670.8 doublet, leading to an upper limit of A(Li)<1.1, hinting to an even deeper Li depletion in TO stars below [Fe/H]=-4. Spectroscopic follow-up is currently being prosecuted by the recently started ESO large program TOPoS, aiming to observe about 80 more EMP candidates.

  11. Beryllium abundances in Hg-Mn stars

    SciTech Connect

    Boesgaard, A.M.; Heacox, W.D.; Wolff, S.C.; Borsenberger, J.; Praderie, F.

    1982-08-15

    The Hg-Mn stars show anomalous line strengths of many chemical elements including Be. We have observed the Be ii resonance doublet at lambdalambda 3130, 3131 at 6.7 A mm/sup -1/ in 43 Hg-Mn stars and 10 normal stars in the same temperature range with the coude spectrograph of the 2.24 m University of Hawaii telescope at Mauna Kea. Measured equivalent widths of the two lines and/or the blend of the doublet have been compared with predictions from (1) LTE model atmospheres and (2) non-LTE line formation on non-LTE model atmospheres. (For strong Be ii lines, the LTE calculations result in more Be by factors of 2 to 4 than do the non-LTE calculations.) Overabundances of factors of 20--2 x 10/sup 4/ relative to solar have been found for 75% of the Hg-Mn stars. The 25% with little or no Be are typically among the cooler Hg-Mn stars, but for the stars with Be excesses, there is only marginal evidence for a correlationi of the size of the overabundance and temperature. It is suggested that diffusion driven by radiation pressure is responsible for the observed Be abundance anomalies.

  12. Late Embryogenesis Abundant (LEA) proteins in legumes

    PubMed Central

    Battaglia, Marina; Covarrubias, Alejandra A.

    2013-01-01

    Plants are exposed to different external conditions that affect growth, development, and productivity. Water deficit is one of these adverse conditions caused by drought, salinity, and extreme temperatures. Plants have developed different responses to prevent, ameliorate or repair the damage inflicted by these stressful environments. One of these responses is the activation of a set of genes encoding a group of hydrophilic proteins that typically accumulate to high levels during seed dehydration, at the last stage of embryogenesis, hence named Late Embryogenesis Abundant (LEA) proteins. LEA proteins also accumulate in response to water limitation in vegetative tissues, and have been classified in seven groups based on their amino acid sequence similarity and on the presence of distinctive conserved motifs. These proteins are widely distributed in the plant kingdom, from ferns to angiosperms, suggesting a relevant role in the plant response to this unfavorable environmental condition. In this review, we analyzed the LEA proteins from those legumes whose complete genomes have been sequenced such as Phaseolus vulgaris, Glycine max, Medicago truncatula, Lotus japonicus, Cajanus cajan, and Cicer arietinum. Considering their distinctive motifs, LEA proteins from the different groups were identified, and their sequence analysis allowed the recognition of novel legume specific motifs. Moreover, we compile their transcript accumulation patterns based on publicly available data. In spite of the limited information on these proteins in legumes, the analysis and data compiled here confirm the high correlation between their accumulation and water deficit, reinforcing their functional relevance under this detrimental conditions. PMID:23805145

  13. Proteomics characterization of abundant Golgi membrane proteins.

    PubMed

    Bell, A W; Ward, M A; Blackstock, W P; Freeman, H N; Choudhary, J S; Lewis, A P; Chotai, D; Fazel, A; Gushue, J N; Paiement, J; Palcy, S; Chevet, E; Lafrenière-Roula, M; Solari, R; Thomas, D Y; Rowley, A; Bergeron, J J

    2001-02-16

    A mass spectrometric analysis of proteins partitioning into Triton X-114 from purified hepatic Golgi apparatus (84% purity by morphometry, 122-fold enrichment over the homogenate for the Golgi marker galactosyl transferase) led to the unambiguous identification of 81 proteins including a novel Golgi-associated protein of 34 kDa (GPP34). The membrane protein complement was resolved by SDS-polyacrylamide gel electrophoresis and subjected to a hierarchical approach using delayed extraction matrix-assisted laser desorption ionization mass spectrometry characterization by peptide mass fingerprinting, tandem mass spectrometry to generate sequence tags, and Edman sequencing of proteins. Major membrane proteins corresponded to known Golgi residents, a Golgi lectin, anterograde cargo, and an abundance of trafficking proteins including KDEL receptors, p24 family members, SNAREs, Rabs, a single ARF-guanine nucleotide exchange factor, and two SCAMPs. Analytical fractionation and gold immunolabeling of proteins in the purified Golgi fraction were used to assess the intra-Golgi and total cellular distribution of GPP34, two SNAREs, SCAMPs, and the trafficking proteins GBF1, BAP31, and alpha(2)P24 identified by the proteomics approach as well as the endoplasmic reticulum contaminant calnexin. Although GPP34 has never previously been identified as a protein, the localization of GPP34 to the Golgi complex, the conservation of GPP34 from yeast to humans, and the cytosolically exposed location of GPP34 predict a role for a novel coat protein in Golgi trafficking.

  14. Chloroflexi bacteria are more diverse, abundant, and similar in high than in low microbial abundance sponges.

    PubMed

    Schmitt, Susanne; Deines, Peter; Behnam, Faris; Wagner, Michael; Taylor, Michael W

    2011-12-01

    Some marine sponges harbor dense and phylogenetically complex microbial communities [high microbial abundance (HMA) sponges] whereas others contain only few and less diverse microorganisms [low microbial abundance (LMA) sponges]. We focused on the phylum Chloroflexi that frequently occurs in sponges to investigate the different associations with three HMA and three LMA sponges from New Zealand. By applying a range of microscopical and molecular techniques a clear dichotomy between HMA and LMA sponges was observed: Chloroflexi bacteria were more abundant and diverse in HMA than in LMA sponges. Moreover, different HMA sponges contain similar Chloroflexi communities whereas LMA sponges harbor different and more variable communities which partly resemble Chloroflexi seawater communities. A comprehensive phylogenetic analysis of our own and publicly available sponge-derived Chloroflexi 16S rRNA gene sequences (> 780 sequences) revealed the enormous diversity of this phylum within sponges including 29 sponge-specific and sponge-coral clusters (SSC/SCC) as well as a 'supercluster' consisting of > 250 sponge-derived and a single nonsponge-derived 16S rRNA gene sequence. Interestingly, the majority of sequences obtained from HMA sponges, but only a few from LMA sponges, fell into SSC/SCC clusters. This indicates a much more specific association of Chloroflexi bacteria with HMA sponges and suggests an ecologically important role for these prominent bacteria.

  15. The Open Cluster Chemical Abundances and Mapping (OCCAM) Survey: Galactic Neutron Capture Abundance Gradients

    NASA Astrophysics Data System (ADS)

    O'Connell, Julia; Frinchaboy, Peter M.; Shetrone, Matthew D.; Melendez, Matthew; Cunha, Katia M. L.; Majewski, Steven R.; Zasowski, Gail; APOGEE Team

    2017-01-01

    The evolution of elements, as a function or age, throughout the Milky Way disk provides a key constraint for galaxy evolution models. In an effort to provide these constraints, we have conducted an investigation into the r- and s- process elemental abundances for a large sample of open clusters as part of an optical follow-up to the SDSS-III/APOGEE-1 survey. Stars were identified as cluster members by the Open Cluster Chemical Abundance & Mapping (OCCAM) survey, which culls member candidates by radial velocity, metallicity, and proper motion from the observed APOGEE sample. To obtain data for neutron capture elements in these clusters, we conducted a long-term observing campaign covering three years (2013-2016) using the McDonald Observatory Otto Struve 2.1-m telescope and Sandiford Cass Echelle Spectrograph (R ~ 60,000). We present Galactic neutron-capture abundance gradients using 30+ clusters, within 6 kpc of the Sun, covering a range of ages from ~80 Myr to ~10 Gyr .

  16. Spatial and temporal abundance patterns of oceanic chaetognaths in the western North Atlantic—I. Hydrographic and seasonal abundance patterns

    NASA Astrophysics Data System (ADS)

    Cheney, Jerry

    1985-09-01

    Chaetognath abundance was measured from 38 MOCNESS tows collected in the western North Atlantic from August 1975 to November 1977. Twenty-one species were identified from 18 slope water (SW), 18 northern Sargasso Sea (NSS) and two Gulf Stream (GS) tows. Sagitta elegans, S. hispida and S. megalophthalma were collected in only one or two tows. Eukrohnia bathypelagica, E. fowleri, E. hamata, Sagitta helenae, S. macrocephala, S. maxima and S. tasmanica are significantly more abundant in the SW than in the NSS. Krohnitta subtilis, Pterosagitta draco, Sagitta bipunctata, S. decipiens, S. hexaptera, S. lyra, S. minima, S. planctonis and S. serratodentata are significantly more abundant in the NSS. Krohnitta pacifica and Sagitta enflata show no significant abundance differences between the SW and NSS. Most species show at least an order of magnitude abundance difference between the SW and NSS, with intermediate GS abundances. A simple mixing model and previous reports of chaetognath distributions in the North Atlantic indicate that most species have expatriate populations in either the SW or NSS or in both regions. Increased temperature and food abundance probably limit SW species from the NSS, while decreased temperature and increased predator abundance probably limit NSS species from the SW. Spring abundance peaks were observed for many species in the NSS, but no seasonal peaks were detected for species in the SW. The spring abundance peaks in the NSS are probably due to increased food abundance, although temperature could not be ruled out as an important factor.

  17. Nanocrystal synthesis and thin film formation for earth abundant photovoltaics

    NASA Astrophysics Data System (ADS)

    Carter, Nathaniel J.

    Providing access to on-demand energy at the global scale is a grand challenge of our time. The fabrication of solar cells from nanocrystal inks comprising earth abundant elements represents a scalable and sustainable photovoltaic technology with the potential to meet the global demand for electricity. Solar cells with Cu2ZnSn(S,Se)4 (CZTSSe) absorber layers are of particular interest due to the high absorption coefficient of CZTSSe, its band gap in the ideal range for efficient photovoltaic power conversion, and the relative abundance of its constituent elements in the earth's crust. Despite the promise of this material system, CZTSSe solar cell efficiencies reported throughout literature have failed to exceed 12.6%, principally due to the low open-circuit voltage (VOC) achieved in these devices compared to the absorber band gap. The work presented herein primarily aims to address the low VOC problem. First, the fundamental cause for such low VOC's is investigated. Interparticle compositional inhomogeneities identified in the synthesized CZTS nanocrystals and their effect on the absorber layer formation and device performance are characterized. Real-time energy-dispersive x-ray diffraction (EDXRD) elucidates the role of these inhomogeneities in the mechanism by which a film of CZTS nanocrystals converts into a dense absorber layer comprising micron-sized CZTSSe grains upon annealing in a selenium atmosphere (selenization). Additionally, a direct correlation between the nanocrystal inhomogeneities and the VOC in completed devices is observed. Detailed characterization of CZTSSe solar cells identifies electrical potential fluctuations in the CZTSSe absorber - due to spatial composition variations not unlike those observed in the nanocrystals - as a primary V OC inhibitor. Additional causes for low VOC's in CZTSSe solar cells proposed in the literature involve recombination at the interface between the CZTSSe absorber and: (1) the n-type, CdS buffer layer, or (2) the

  18. Electricity in the Atmosphere.

    ERIC Educational Resources Information Center

    Sampath, S.; Kumar, V. Sasi

    1991-01-01

    The theory of the atmospheric electric circuit and a discussion of the fair-weather electrical are presented. The ion concentration, mobility, conductivity, and electric field altitudinal profiles are explained. An outline of the electrical processes inside thunderstorms along with a description of the lightning strike are included. (Author)

  19. Industrial perspectives on earth abundant, multinary thin film photovoltaics

    NASA Astrophysics Data System (ADS)

    Haight, Richard; Gershon, Talia; Gunawan, Oki; Antunez, Priscilla; Bishop, Douglas; Seog Lee, Yun; Gokmen, Tayfun; Sardashti, Kasra; Chagarov, Evgueni; Kummel, Andrew

    2017-03-01

    The most efficient earth abundant, non-toxic thin film multelemental PV devices are fabricated from Cu, Zn, Sn, S and Se, with the chemical formula of Cu2ZnSn(S x Se1‑x )4 (CZTS,Se). This material has enjoyed relatively rapid increases in efficiency from its inception to its present-day power conversion efficiency of 12.6%. But further increases in efficiency have been hampered by the inability to substantially increase Voc, the open circuit voltage. In this review article we will discuss the fundamentals of this important kesterite material including methods of film growth, post growth processing and device fabrication. Detailed studies of the properties of CZTS,Se including chemical, structural and electronic as well as full device electrical characterization have been performed in an effort to coax out the critical issues that limit performance. These experimental studies, enhanced by density functional theory calculations have pointed to fundamental bulk point defects, such as Cu–Zn antisites, and clusters of defects, as the primary culprits in limiting Voc increases. Improvements in device performance through grain boundary passivation and interface modifications are described. Exfoliation of functioning solar cells to expose the back surface along with engineering of new back contacts designed to impose electrostatic fields that drive electron-hole separation and increase Voc are discussed. A parallel route to increasing device performance by alloying Ag with CZTS,Se in order to inhibit Cu–Zn antisite defect formation has shown significant improvement in material properties. Finally, applications of high S (and hence higher Voc) CZTS,Se based devices to energy harvesting for ‘Internet-of-Things’ devices is discussed.

  20. Abundance models improve spatial and temporal prioritization of conservation resources.

    PubMed

    Johnston, Alison; Fink, Daniel; Reynolds, Mark D; Hochachka, Wesley M; Sullivan, Brian L; Bruns, Nicholas E; Hallstein, Eric; Merrifield, Matt S; Matsumoto, Sandi; Kelling, Steve

    2015-10-01

    Conservation prioritization requires knowledge about organism distribution and density. This information is often inferred from models that estimate the probability of species occurrence rather than from models that estimate species abundance, because abundance data are harder to obtain and model. However, occurrence and abundance may not display similar patterns and therefore development of robust, scalable, abundance models is critical to ensuring that scarce conservation resources are applied where they can have the greatest benefits. Motivated by a dynamic land conservation program, we develop and assess a general method for modeling relative abundance using citizen science monitoring data. Weekly estimates of relative abundance and occurrence were compared for prioritizing times and locations of conservation actions for migratory waterbird species in California, USA. We found that abundance estimates consistently provided better rankings of observed counts than occurrence estimates. Additionally, the relationship between abundance and occurrence was nonlinear and varied by species and season. Across species, locations prioritized by occurrence models had only 10-58% overlap with locations prioritized by abundance models, highlighting that occurrence models will not typically identify the locations of highest abundance that are vital for conservation of populations.

  1. The Origin of Element Abundance Variations in Solar Energetic Particles

    NASA Astrophysics Data System (ADS)

    Reames, Donald V.

    2016-08-01

    Abundance enhancements, during acceleration and transport in both gradual and impulsive solar energetic particle (SEP) events, vary approximately as power laws in the mass-to-charge ratio [A/Q] of the ions. Since the Q-values depend upon the electron temperature of the source plasma, this has allowed a determination of this temperature from the pattern of element-abundance enhancements and a verification of the expected inverse-time dependence of the power of A/Q for diffusive transport of ions from the SEP events, with scattering mean free paths found to be between 0.2 and 1 AU. SEP events derived from plasma of different temperatures map into different regions in typical cross-plots of abundances, spreading the distributions. In comparisons of SEP events with temperatures above 2 MK, impulsive events show much broader non-thermal variation of abundances than do gradual events. The extensive shock waves accelerating ions in gradual events may average over much of an active region where numerous but smaller magnetic reconnections, "nanojets", produce suprathermal seed ions, thus averaging over varying abundances, while an impulsive SEP event only samples one local region of abundance variations. Evidence for a reference He/O-abundance ratio of 91, rather than 57, is also found for the hotter plasma. However, while this is similar to the solar-wind abundance of He/O, the solar-wind abundances otherwise provide an unacceptably poor reference for the SEP-abundance enhancements, generating extremely large errors.

  2. Abundances, planetary nebulae, and stellar evolution

    NASA Astrophysics Data System (ADS)

    Aller, Lawrence H.

    1994-09-01

    Among Henry Norris Russell's many achievements were his contributions to solar and stellar spectroscopy, in particular, to an analysis of the chemical composition of the solar atmosphere. The question of composition differences between stars was hotly debated; some distinguished astronomers argued that all stars had the solar composition. Some early challenges to this doctrine are described. Determinations of chemical compositions of gaseous nebulae were much more difficult. If we observe the lines of a given chemical element in one ionization stage in a stellar spectrum, we can deduce readily the abundance of that element. No such luxury is available for a planetary or diffuse gaseous nebula. We must measure lines of as many ionization stages as we can. Furthermore, a nebula is an extended object. Often detailed spectroscopy is at hand only for narrow pencil columns taken through the image. Different observers use a variety of apertures. Fortunately it is possible to calculate theoretical spectra for any arbitrary cross section taken through a symmetrical model, so UV, optical, and IR observations all can be compared properly with a prediction. The value of high-resolution spectra obtained with instruments such as the Hamilton Echelle Spectrograph at Lick Observatory is emphasized. Improved fluxes for weak but important transitions are found. Close blends of lines of different ions can be resolved, and checks can be made on predictions of atomic parameters such as Einstein A-values and collision strengths. High spectral resolution data have been obtained and reduced for 22 planetary nebulae of varying size, structure, stellar population membership, dustiness, level of excitation, evolutionary status, and chemical compositions. The promise seems justified that with such extensive, high quality data, additional insights on nebular genesis and late states of stellar evolution can be found. The present survey is confined to nebulae of high surface brightness, but

  3. Comparing halo bias from abundance and clustering

    NASA Astrophysics Data System (ADS)

    Hoffmann, K.; Bel, J.; Gaztañaga, E.

    2015-06-01

    We model the abundance of haloes in the ˜(3 Gpc h-1)3 volume of the MICE Grand Challenge simulation by fitting the universal mass function with an improved Jackknife error covariance estimator that matches theory predictions. We present unifying relations between different fitting models and new predictions for linear (b1) and non-linear (c2 and c3) halo clustering bias. Different mass function fits show strong variations in their performance when including the low mass range (Mh ≲ 3 × 1012 M⊙ h-1) in the analysis. Together with fits from the literature, we find an overall variation in the amplitudes of around 10 per cent in the low mass and up to 50 per cent in the high mass (galaxy cluster) range (Mh > 1014 M⊙ h-1). These variations propagate into a 10 per cent change in b1 predictions and a 50 per cent change in c2 or c3. Despite these strong variations, we find universal relations between b1 and c2 or c3 for which we provide simple fits. Excluding low-mass haloes, different models fitted with reasonable goodness in this analysis, show per cent level agreement in their b1 predictions, but are systematically 5-10 per cent lower than the bias directly measured with two-point halo-mass clustering. This result confirms previous findings derived from smaller volumes (and smaller masses). Inaccuracies in the bias predictions lead to 5-10 per cent errors in growth measurements. They also affect any halo occupation distribution fitting or (cluster) mass calibration from clustering measurements.

  4. Abundances, planetary nebulae, and stellar evolution

    NASA Technical Reports Server (NTRS)

    Aller, Lawrence H.

    1994-01-01

    Among Henry Norris Russell's many achievements were his contributions to solar and stellar spectroscopy, in particular, to an analysis of the chemical composition of the solar atmosphere. The question of composition differences between stars was hotly debated; some distinguished astronomers argued that all stars had the solar composition. Some early challenges to this doctrine are described. Determinations of chemical compositions of gaseous nebulae were much more difficult. If we observe the lines of a given chemical element in one ionization stage in a stellar spectrum, we can deduce readily the abundance of that element. No such luxury is available for a planetary or diffuse gaseous nebula. We must measure lines of as many ionization stages as we can. Furthermore, a nebula is an extended object. Often detailed spectroscopy is at hand only for narrow pencil columns taken through the image. Different observers use a variety of apertures. Fortunately it is possible to calculate theoretical spectra for any arbitrary cross section taken through a symmetrical model, so UV, optical, and IR observations all can be compared properly with a prediction. The value of high-resolution spectra obtained with instruments such as the Hamilton Echelle Spectrograph at Lick Observatory is emphasized. Improved fluxes for weak but important transitions are found. Close blends of lines of different ions can be resolved, and checks can be made on predictions of atomic parameters such as Einstein A-values and collision strengths. High spectral resolution data have been obtained and reduced for 22 planetary nebulae of varying size, structure, stellar population membership, dustiness, level of excitation, evolutionary status, and chemical compositions. The promise seems justified that with such extensive, high quality data, additional insights on nebular genesis and late states of stellar evolution can be found. The present survey is confined to nebulae of high surface brightness, but

  5. On the sodium abundance in cometary meteoroids

    NASA Astrophysics Data System (ADS)

    Trigo-Rodriguez, J. M.; Llorca, J.

    We have obtained the chemical abundances of Na, Mg, Ca, Ti, Cr, Mn, Fe, Co and Ni relative to Si for thirteen fireballs, most of them produced by cometary meteoroids. We used a model developed by Borovicka (1993) to determine realistic physical parameters in the meteor column and the relative chemical abundances along the fireball path (Trigo-Rodriguez et al., 2003). Although most of the relative elemental chemical abundances in meteoroids fit well with chondritic values, we have noted that sodium is overabundant in meteor columns (Trigo-Rodriguez et al., 2004). This overabundance is accompanied by other interesting patterns: (i) The spectral lines associated with multiplet 1 of Na I usually appear before the lines of other elements. This could be related to some volatile phase that is easily removed from the meteoroid in the first steps of ablation. Different reservoirs of easily-removable Na may be present in cometary meteoroids, such as organics or phyllosilicates (Trigo-Rodriguez et al., 2004); (ii) The intensity of the Na I lines increases in bright flares associated with the process of fragmentation of the incoming meteoroid. If the structure of cometary meteoroids is similar to the dustball model invoked by Hawkes & Jones (1975), Na could be present as a mineral phase "gluing" mineral grains and, in consequence, it would be released easily during fragmentation events. Although Na is practically omnipresent in cometary meteor spectra, Na-bearing phases are rare in aggregate and cluster Interplanetary Dust Particles (IDPs) and usually the Na/Si ratio is clearly below the chondritic value (Rietmeijer, 2002). Our analysis, however, shows that sodium is overabundant in cometary meteoroids (Trigo-Rodriguez et al., 2004). One possibility, as proposed by Rietmeijer (1999), is that the accepted cosmic ratio of Na/Si is not accurate, being two times the currently accepted value. In any case, our idea is that an important part of the sodium present in meteoroids is

  6. Protein separation using an electrically tunable membrane

    NASA Astrophysics Data System (ADS)

    Jou, Ining; Melnikov, Dmitriy; Gracheva, Maria

    Separation of small proteins by charge with a solid-state porous membrane requires control over the protein's movement. Semiconductor membrane has this ability due to the electrically tunable electric potential profile inside the nanopore. In this work we investigate the possibility to separate the solution of two similar sized proteins by charge. As an example, we consider two small globular proteins abundant in humans: insulin (negatively charged) and ubiquitin (neutral). We find that the localized electric field inside the pore either attracts or repels the charged protein to or from the pore wall which affects the delay time before a successful translocation of the protein through the nanopore. However, the motion of the uncharged ubiquitin is unaffected. The difference in the delay time (and hence the separation) can be further increased by the application of the electrolyte bias which induces an electroosmotic flow in the pore. NSF DMR and CBET Grant No. 1352218.

  7. Tailoring of the electrical and thermal properties using ultra-short period non-symmetric superlattices

    NASA Astrophysics Data System (ADS)

    Komar, Paulina; Chávez-Ángel, Emigdio; Euler, Christoph; Balke, Benjamin; Kolb, Ute; Müller, Mathis M.; Kleebe, Hans-Joachim; Fecher, Gerhard H.; Jakob, Gerhard

    2016-10-01

    Thermoelectric modules based on half-Heusler compounds offer a cheap and clean way to create eco-friendly electrical energy from waste heat. Here we study the impact of the period composition on the electrical and thermal properties in non-symmetric superlattices, where the ratio of components varies according to (TiNiSn)n:(HfNiSn)6-n, and 0 ⩽ n ⩽ 6 unit cells. The thermal conductivity (κ) showed a strong dependence on the material content achieving a minimum value for n = 3, whereas the highest value of the figure of merit ZT was achieved for n = 4. The measured κ can be well modeled using non-symmetric strain relaxation applied to the model of the series of thermal resistances.

  8. Abiotic mediation of a mutualism drives herbivore abundance.

    PubMed

    Mooney, Emily H; Phillips, Joseph S; Tillberg, Chadwick V; Sandrow, Cheryl; Nelson, Annika S; Mooney, Kailen A

    2016-01-01

    Species abundance is typically determined by the abiotic environment, but the extent to which such effects occur through the mediation of biotic interactions, including mutualisms, is unknown. We explored how light environment (open meadow vs. shaded understory) mediates the abundance and ant tending of the aphid Aphis helianthi feeding on the herb Ligusticum porteri. Yearly surveys consistently found aphids to be more than 17-fold more abundant on open meadow plants than on shaded understory plants. Manipulations demonstrated that this abundance pattern was not due to the direct effects of light environment on aphid performance, or indirectly through host plant quality or the effects of predators. Instead, open meadows had higher ant abundance and per capita rates of aphid tending and, accordingly, ants increased aphid population growth in meadow but not understory environments. The abiotic environment thus drives the abundance of this herbivore exclusively through the mediation of a protection mutualism.

  9. 3D model atmospheres and the solar photospheric oxygen abundance

    NASA Astrophysics Data System (ADS)

    Caffau, E.; Ludwig, H.-G.

    2008-10-01

    In recent years the photospheric solar oxygen abundance experienced a significant downward revision. However, a low photospheric abundance is incompatible with the value in the solar interior inferred from helioseismology. For contributing to the dispute whether the solar oxygen abundance is “high” or “low”, we re-derived its photospheric abundance independently of previous analyses. We applied 3D (CO5BOLD) as well as 1D model atmospheres. We considered standard disc-centre and disc-integrated spectral atlases, as well as newly acquired solar intensity spectra at different heliocentric angles. We determined the oxygen abundances from equivalent width and/or line profile fitting of a number of atomic lines. As preliminary result, we find an oxygen abundance in the range 8.73 8.79, encompassing the value obtained by Holweger (2001), and somewhat higher than the value obtained by Asplund et al. (2005).

  10. Light-element abundances in 20 F and G dwarfs

    NASA Astrophysics Data System (ADS)

    Tomkin, J.; Lambert, D. L.; Balachandran, S.

    1985-03-01

    Red and near-IR spectral lines of the Galaxy are analyzed to extract Na, Mg, Al, Si and Ca abundances. The data were obtained using a 2.7 m telescope fitted with a coudespectrograph and a Reticon photodiode array tuned to the 6160, 6350, 6570, 6696, 7860 and 8740 wavelengths of 20 F and G dwarfs in the disk and halo. The abundances were then compared to recorded Fe abundances, particularly the forbidden Fe/H ratio. Even numbered atomic number elemental abundances followed the ratio down to values of -0.4, then increased relative to Fe in the transition from disk to halo. The abundances of odd-numbered elements more closely tracked the abundance of Mg in the disk, and experienced a fairly abrupt decrease in the disk-halo transition.

  11. Surplus from and storage of electricity generated by intermittent sources

    NASA Astrophysics Data System (ADS)

    Wagner, Friedrich

    2016-12-01

    Data from the German electricity system for the years 2010, 2012, 2013, and 2015 are used and scaled up to a 100% supply by intermittent renewable energy sources (iRES). In the average, 330GW wind and PV power are required to meet this 100% target. A back-up system is necessary with the power of 89% of peak load. Surplus electricity accrues at high power levels. Curtailing surplus power to a large extent is found to be uneconomic. Demand-side management will suffer from the strong day-to-day variation of available surplus energy. A day storage is ineffective because of the day-night correlation of surplus power during winter. A seasonal storage loses its character when transformation losses are considered because it can contribute only after periods with excessive surplus production. The option of an oversized iRES system to feed the storage is also not effective because, in this case, energy can be taken directly from the large iRES supply, making storage superfluous. The capacities to be installed stress the difficulty to base heat supply and mobility also on iRES generated electricity in the future. As the German energy transition replaces one CO2-free electricity supply system by another one, no major reduction in CO2 emission can be expected till 2022, when the last nuclear reactor will be switched off. By 2022, an extremely oversized power supply system has to be created, which can be expected to continue running down spot-market electricity prices. The continuation of the economic response -to replace expensive gas fuel by cheap lignite- causes an overall increase in CO2 emission. The German GHG emission targets for 2020 and beyond are therefore in jeopardy.

  12. Heavy Element Abundances in NGC 5846

    NASA Technical Reports Server (NTRS)

    Jones, Christine

    2000-01-01

    In this paper we analyze the diffuse X-ray coronae surrounding the elliptical galaxy NGC 5846, combining measurements from two observatories, ROSAT and the Advanced Satellite for Cosmology and Astrophysics. We map the gas temperature distribution and find a central cool region within an approximately isothermal gas halo extending to a radius of about 50 kpc and evidence for a temperature decrease at larger radii. With a radially falling temperature profile, the total mass converges to (9.6 +/- 1.0) x 10(exp 12) solar mass at 230 kpc radius. This corresponds to a total mass to blue light ratio of 53 +/- 5 solar mass/solar luminosity. As in other early type galaxies, the gas mass is only a few percent of the total mass. Using the spectroscopic measurements, we also derive radial distributions for the heavy elements silicon and iron and find that the abundances of both decrease with galaxy radius. The mass ratio of Si to Fe lies between the theoretical predictions for element production in SN Ia and SN II, suggesting an important role for SN Ia, as well as SN II, for gas enrichment in ellipticals. Using the 2 SN la yield of Si, we set an upper limit of 0.012 h(sup 2, sub 50) solar neutrino units (SNU) for the SN Ia rate at radii >50 kpc, which is independent of possible uncertainties in the iron L-shell modeling. We compare our observations with the theoretical predictions for the chemical evolution of ellipticals. We conclude that the metal content in stars, if explained by the star formation duration, requires a significant decline in the duration of star formation with galaxy radius, ranging from 1 Gyr at the center to 0.01 Gyr at 100 kpc radius. Alternatively, the decline in metallicity with galaxy radius may be caused by a similar drop with radius in the efficiency of star formation. Based on the Si and Fe measurements presented in this paper, we conclude that the latter scenario is preferred unless a dependence of the SN Ia rate on stellar metallicity is invoked.

  13. Longevity and aging in insects: Is reproduction costly; cheap; beneficial or irrelevant? A critical evaluation of the "trade-off" concept.

    PubMed

    De Loof, Arnold

    2011-01-01

    The most prevalent hypothesis concerning the relationship between reproduction and longevity predicts that reproduction is costly, particularly in females. Specifically, egg production and sexual harassment of females by males reduce female longevity. This may apply to some short-lived species such as Drosophila, but not to some long-lived species such as the queens of ants and bees. Bee queens lay up to 2000 eggs a day for several years, but they nevertheless live at least 20 times longer than their sisters, the sterile workers. This discrepancy necessitates a critical reevaluation of the validity of both the trade-off concept as such, and of the current theories of aging. The widely accepted oxidative stress theory of aging with its links to metabolism and the insulin/IGF-I system has been disproven in Caenorhabditis elegans and mice, but not in Drosophila, necessitating other approaches. The recent spermidine/mitophagy theory is gaining momentum. Two major mechanisms may have been largely overlooked, namely epigenetic control of longevity by imprinting through DNA methylation as suggested by recent data in the honey bee, and especially, a mechanism of which the principles are outlined here, the progressive weakening of the "electrical dimension" of cells up to the point of total collapse, namely death.

  14. Origin of Stellar Abundances in the early Galaxy

    SciTech Connect

    Montes, F.; Beers, T. C.; Cowan, J.; Elliot, T.; Schatz, H.; Farouqi, K.; Gallino, R.; Heil, M.; Kratz, K.-L.; Pfeiffer, B.; Pignatari, M.

    2007-10-26

    Observations of metal-poor stars in the last decade have revealed an abundance pattern that have recently been explained as the result of two nucleosynthesis processes, a strong r-process that creates most of the Z{>=}56 and some 38{<=}Z{<=}47 abundances and a light element primary process (LEPP) responsible for creating the remaining 38{<=}Z{<=}47 abundances and some small contribution to heavier elements. We review some of the current literature on the LEPP and show a derived abundance pattern as a function of mass number.

  15. Abundance of birds in Fukushima as judged from Chernobyl.

    PubMed

    Møller, Anders Pape; Hagiwara, Atsushi; Matsui, Shin; Kasahara, Satoe; Kawatsu, Kencho; Nishiumi, Isao; Suzuki, Hiroyuki; Ueda, Keisuke; Mousseau, Timothy A

    2012-05-01

    The effects of radiation on abundance of common birds in Fukushima can be assessed from the effects of radiation in Chernobyl. Abundance of birds was negatively related to radiation, with a significant difference between Fukushima and Chernobyl. Analysis of 14 species common to the two areas revealed a negative effect of radiation on abundance, differing between areas and species. The relationship between abundance and radiation was more strongly negative in Fukushima than in Chernobyl for the same 14 species, demonstrating a negative consequence of radiation for birds immediately after the accident on 11 March 2011 during the main breeding season in March-July, when individuals work close to their maximum sustainable level.

  16. Digestion and depletion of abundant proteins improves proteomic coverage

    PubMed Central

    Fonslow, Bryan R.; Stein, Benjamin D.; Webb, Kristofor J.; Xu, Tao; Choi, Jeong; Park, Sung Kyu; Yates, John R.

    2012-01-01

    Two major challenges in proteomics are the large number of proteins and their broad dynamic range within the cell. We exploited the abundance-dependent Michaelis-Menten kinetics of trypsin digestion to selectively digest and deplete abundant proteins with a method we call DigDeAPr. We validated the depletion mechanism with known yeast protein abundances and observed greater than 3-fold improvement in low abundance human protein identification and quantitation metrics. This methodology should be broadly applicable to many organisms, proteases, and proteomic pipelines. PMID:23160281

  17. Analysis of organo-chlorine pesticides residue in raw coffee with a modified "quick easy cheap effective rugged and safe" extraction/clean up procedure for reducing the impact of caffeine on the gas chromatography-mass spectrometry measurement.

    PubMed

    Bresin, Bruno; Piol, Maria; Fabbro, Denis; Mancini, Maria Antonietta; Casetta, Bruno; Del Bianco, Clorinda

    2015-01-09

    The control of pesticide residues on raw coffee is a task of great importance due to high consumption of this beverage in Italy and in many other countries. High caffeine content can hamper extraction and measurement of any pesticide residue. A tandem extraction protocol has been devised by exploiting the quick easy cheap effective rugged and safe (QuEChERS) scheme for extraction, coupled to a dispersive liquid-liquid micro-extraction (DLLME) in order to drastically reduce caffeine content in the final extract. Gas chromatography-mass spectrometry (GC-MS) has been used for quantification of organo-chlorine pesticides in single ion monitoring (SIM) mode. Method has been validated and performances meet the criteria prescribed by European Union regulations.

  18. Double stars measurements with cheap CCD sensors (French Title: Mesures d'étoiles doubles visuelles réalisées à l'aide de capteurs dtc de grande diffusion)

    NASA Astrophysics Data System (ADS)

    Losse, F.

    2005-09-01

    This paper presents 262 measurements of visual binaries. They essentially come from a three years evaluation period of cheap CCD sensors coupled with either off the shelves or modified webcam electronics. The evaluation cycle and results are largely described in Bulletin n°40 de la Commission des Etoiles Doubles (Sept. 2002 - Société Astronomique de France). These devices can produce measurements as consistent as those obtained with a filar micrometer on the same 8" telescope. The most recent measurements (epoch 2004+) were obtained with an "Audine" camera shipped with a KAF400. Besides the stars visited for evaluation purpose, we present some systems of interest : 17 orbital binaries, 35 neglected systems, 15 confirmations and 2 discoveries of a third component in already known systems.

  19. An innovative method based on quick, easy, cheap, effective, rugged, and safe extraction coupled to desorption electrospray ionization-high resolution mass spectrometry for screening the presence of paralytic shellfish toxins in clams.

    PubMed

    Mattarozzi, Monica; Bianchi, Federica; Milioli, Marco; Cavazza, Antonella; Careri, Maria

    2016-01-15

    The capabilities of desorption electrospray ionization-high resolution mass spectrometry (DESI-HRMS) were tested for screening the presence of some paralytic shellfish toxins in clams. A quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach is proposed for sample clean-up. QuEChERS extraction was optimized by using a full factorial design followed by the multicriteria method of the desirability functions. Quantitation limits in the microgram per kilogram range proved reliability of the method for the detection of the investigated toxins in accordance to the rules laid down by European legislation. The optimized QuEChERS-DESI-HRMS based-method allowed for a rapid reliable screening of the investigated compounds at levels of interest, thus being useful for high-throughput analyses.

  20. Electric arc saw apparatus

    DOEpatents

    Deichelbohrer, Paul R [Richland, WA

    1986-01-01

    A portable, hand held electric arc saw has a small frame for supporting an electrically conducting rotary blade which serves as an electrode for generating an electric arc to erode a workpiece. Electric current is supplied to the blade by biased brushes and a slip ring which are mounted in the frame. A pair of freely movable endless belts in the form of crawler treads stretched between two pulleys are used to facilitate movement of the electric arc saw. The pulleys are formed of dielectric material to electrically insulate the crawler treads from the frame.

  1. Stellar oxygen abundances. I - A resolution to the 7774 A O I abundance discrepancy

    NASA Astrophysics Data System (ADS)

    King, Jeremy R.

    1993-09-01

    We investigate the discrepancy between O/Fe abundance ratios of metal-poor stars derived from the 7774 A O I triplet and O/Fe ratios determined from other oxygen lines. We propose a possible resolution to this discrepancy which also eliminates the correlation of O/Fe and T(eff) found in a recent 7774 A O I analysis. The equivalent widths of Abia & Rebolo (1989) are found to be systematically too high by 25 percent. Arguments are presented that current temperature estimates for halo stars are 150-200 K too low. Using the guidance of both model atmospheres and other empirical color-T(eff) relations, we construct new color temperature relations for metal-poor stars. These relations are tied to the temperature scale of Saxner & Hammarback (1985) for metal-rich stars. We use (b-y) and (V-K) indices to redetermine values of T(eff) for a handful of halo stars. (B-V)-T(eff) relations which do not take into account the effects of metallicity are found to be inadequate. Revised O/Fe ratios are determined using the new temperature scale. The mean abundance ratio of the reanalyzed halo dwarfs is about +0.52. There is no trend of O/Fe with Fe/H or T(eff).

  2. Herbivore regulation of plant abundance in aquatic ecosystems.

    PubMed

    Wood, Kevin A; O'Hare, Matthew T; McDonald, Claire; Searle, Kate R; Daunt, Francis; Stillman, Richard A

    2017-05-01

    Herbivory is a fundamental process that controls primary producer abundance and regulates energy and nutrient flows to higher trophic levels. Despite the recent proliferation of small-scale studies on herbivore effects on aquatic plants, there remains limited understanding of the factors that control consumer regulation of vascular plants in aquatic ecosystems. Our current knowledge of the regulation of primary producers has hindered efforts to understand the structure and functioning of aquatic ecosystems, and to manage such ecosystems effectively. We conducted a global meta-analysis of the outcomes of plant-herbivore interactions using a data set comprised of 326 values from 163 studies, in order to test two mechanistic hypotheses: first, that greater negative changes in plant abundance would be associated with higher herbivore biomass densities; second, that the magnitude of changes in plant abundance would vary with herbivore taxonomic identity. We found evidence that plant abundance declined with increased herbivore density, with plants eliminated at high densities. Significant between-taxa differences in impact were detected, with insects associated with smaller reductions in plant abundance than all other taxa. Similarly, birds caused smaller reductions in plant abundance than echinoderms, fish, or molluscs. Furthermore, larger reductions in plant abundance were detected for fish relative to crustaceans. We found a positive relationship between herbivore species richness and change in plant abundance, with the strongest reductions in plant abundance reported for low herbivore species richness, suggesting that greater herbivore diversity may protect against large reductions in plant abundance. Finally, we found that herbivore-plant nativeness was a key factor affecting the magnitude of herbivore impacts on plant abundance across a wide range of species assemblages. Assemblages comprised of invasive herbivores and native plant assemblages were associated with

  3. Climatic effects on mosquito abundance in Mediterranean wetlands

    PubMed Central

    2014-01-01

    Background The impact of climate change on vector-borne diseases is highly controversial. One of the principal points of debate is whether or not climate influences mosquito abundance, a key factor in disease transmission. Methods To test this hypothesis, we analysed ten years of data (2003–2012) from biweekly surveys to assess inter-annual and seasonal relationships between the abundance of seven mosquito species known to be pathogen vectors (West Nile virus, Usutu virus, dirofilariasis and Plasmodium sp.) and several climatic variables in two wetlands in SW Spain. Results Within-season abundance patterns were related to climatic variables (i.e. temperature, rainfall, tide heights, relative humidity and photoperiod) that varied according to the mosquito species in question. Rainfall during winter months was positively related to Culex pipiens and Ochlerotatus detritus annual abundances. Annual maximum temperatures were non-linearly related to annual Cx. pipiens abundance, while annual mean temperatures were positively related to annual Ochlerotatus caspius abundance. Finally, we modelled shifts in mosquito abundances using the A2 and B2 temperature and rainfall climate change scenarios for the period 2011–2100. While Oc. caspius, an important anthropophilic species, may increase in abundance, no changes are expected for Cx. pipiens or the salt-marsh mosquito Oc. detritus. Conclusions Our results highlight that the effects of climate are species-specific, place-specific and non-linear and that linear approaches will therefore overestimate the effect of climate change on mosquito abundances at high temperatures. Climate warming does not necessarily lead to an increase in mosquito abundance in natural Mediterranean wetlands and will affect, above all, species such as Oc. caspius whose numbers are not closely linked to rainfall and are influenced, rather, by local tidal patterns and temperatures. The final impact of changes in vector abundance on disease frequency

  4. Electric potential and electric field imaging

    NASA Astrophysics Data System (ADS)

    Generazio, E. R.

    2017-02-01

    The technology and methods for remote quantitative imaging of electrostatic potentials and electrostatic fields in and around objects and in free space is presented. Electric field imaging (EFI) technology may be applied to characterize intrinsic or existing electric potentials and electric fields, or an externally generated electrostatic field made be used for "illuminating" volumes to be inspected with EFI. The baseline sensor technology (e-Sensor) and its construction, optional electric field generation (quasi-static generator), and current e-Sensor enhancements (ephemeral e-Sensor) are discussed. Demonstrations for structural, electronic, human, and memory applications are shown. This new EFI capability is demonstrated to reveal characterization of electric charge distribution creating a new field of study embracing areas of interest including electrostatic discharge (ESD) mitigation, crime scene forensics, design and materials selection for advanced sensors, dielectric morphology of structures, tether integrity, organic molecular memory, and medical diagnostic and treatment efficacy applications such as cardiac polarization wave propagation and electromyography imaging.

  5. Nucleosynthesis: Stellar and Solar Abundances and Atomic Data

    NASA Technical Reports Server (NTRS)

    Cowan, John J.; Lawler, James E.; Sneden, Christopher; DenHartog, E. A.; Collier, Jason; Dodge, Homer L.

    2006-01-01

    Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the Galaxy the progenitors of the halo stars responsible for neutron-capture synthesis. Comparisons of abundance trends can be used to understand the chemical evolution of the Galaxy and the nature of heavy element nucleosynthesis. In addition age determinations, based upon long-lived radioactive nuclei abundances, can now be obtained. These stellar abundance determinations depend critically upon atomic data. Improved laboratory transition probabilities have been recently obtained for a number of elements. These new gf values have been used to greatly refine the abundances of neutron-capture elemental abundances in the solar photosphere and in very metal-poor Galactic halo stars. The newly determined stellar abundances are surprisingly consistent with a (relative) Solar System r-process pattern, and are also consistent with abundance predictions expected from such neutron-capture nucleosynthesis.

  6. Elemental abundances of the B6 IV star Xi Octantis

    NASA Technical Reports Server (NTRS)

    Adelman, Saul J.; Robinson, Richard D.; Wahlgren, Glenn M.

    1993-01-01

    An elemental abundance study used AAT echelle spectrograms of the ultrasharp-lined, superficially normal B6 IV star Xi Octantis. The derived abundances fall within the trends of values derived for normal B main-sequence band stars. On average, they are 0.28 dex less than solar.

  7. The Abundance and Distribution of Presolar Materials in Cluster IDPS

    NASA Technical Reports Server (NTRS)

    Messenger, Scott; Keller, Lindsay; Nakamura-Messenger, Keiko; Ito, Motoo

    2007-01-01

    Presolar grains and remnants of interstellar organic compounds occur in a wide range of primitive solar system materials, including meteorites, interplanetary dust particles (IDPs), and comet Wild-2 samples. Among the most abundant presolar phases are silicate stardust grains and molecular cloud material. However, these materials have also been susceptible to destruction and alteration during parent body and nebular processing. In addition to their importance as direct samples of remote and ancient astrophysical environments, presolar materials thus provide a measure of how well different primitive bodies have preserved the original solar system starting materials. The matrix normalized abundances of presolar silicate grains in meteorites range from 20 ppm in Semarkona and Bishunpur to 170 ppm for Acfer 094. The lower abundances of presolar silicates in Bishunpur and Semarkona has been ascribed to the destruction of presolar silicates during aqueous processes. Presolar silicates appear to be significantly more abundant in anhydrous IDPs, possibly because these materials did not experience parent body hydrothermal alteration. Among IDPs the estimated abundances of presolar silicates vary by more than an order of magnitude, from 480 to 5500 ppm. The wide disparity in the abundances of presolar silicates of IDPs may be a consequence of the relatively small total area analyzed in those studies and the fine grain sizes of the IDPs. Alternatively, there may be a wide range in presolar silicate abundances between different IDPs. This view is supported by the observation that 15N-rich IDPs have higher presolar silicate abundances than those with isotopically normal N.

  8. Phytoplankton abundance, dominance and coexistence in an eutrophic reservoir in the state of Pernambuco, Northeast Brazil.

    PubMed

    Lira, Giulliari A S T; Araújo, Elcida L; Bittencourt-Oliveira, Maria Do Carmo; Moura, Ariadne N

    2011-12-01

    The present study reports the phytoplankton abundance, dominance and co-existence relationships in the eutrophic Carpina reservoir, Pernambuco, Brazil. Sampling was carried out at six different depths bimonthly at a single reservoir spanning two climatic periods: dry season (January, September, and November 2006) and rainy season (March, May, and July 2006). Density, abundance, dominance, specific diversity and equitability of the community were determined, along with chlorophyll a, and physical and chemical variables of the environment. Eight species were considered abundant, and their densities corresponded to more than 90% of the total phytoplankton community quantified. Cyanobacteria represented more than 80% of this density. Cylindrospermopsis raciborskii was the only dominant taxon in the dry season, and was co-dominant in the rainy season. C. raciborskii, Planktothrix agardhii and Geitlerinema amphibium had the greatest densities and lowest vertical variation coefficients. The statistical analysis indicated relationships with vertical and seasonal variations in the phytoplankton community and the following variables: total dissolved solids, water temperature, electrical conductivity and pH. The changes in the environmental variables were discrete and regulated by the establishment of precipitation however, they were able to promote vertical and seasonal instability in the structure of the phytoplankton community.

  9. Electricity and Magnetism

    NASA Astrophysics Data System (ADS)

    Glazebrook, R. T.

    2016-10-01

    1. Electrostatics: fundamental facts; 2. Electricity as a measurable quantity; 3. Measurement of electric force and potential; 4. Condensers; 5. Electrical machines; 6. Measurement of potential and electric force; 7. Magnetic attraction and repulsion; 8. Laws of magnetic force; 9. Experiments with magnets; 10. Magnetic calculations; 11. Magnetic measurements; 12. Terrestrial magnetism; 13. The electric current; 14. Relation between electromagnetic force and current; 15. Measurement of current; 16. Measurement of resistance and electromotive force; 17. Measurement of quantity of electricity, condensers; 18. Thermal activity of a current; 19. The voltaic cell (theory); 20. Electromagnetism; 21. Magnetisation of iron; 22. Electromagnetic instruments; 23. Electromagnetic induction; 24. Applications of electromagnetic induction; 25. Telegraphy and telephony; 26. Electric waves; 27. Transference of electricity through gases: corpuscles and electrons; Answers to examples; Index.

  10. Renewable Electricity Futures (Presentation)

    SciTech Connect

    Hand, M. M.

    2012-09-01

    This presentation summarizes findings of NREL's Renewable Electricity Futures study, published in June 2012. RE Futures investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050.

  11. Renewable Electricity Futures (Presentation)

    SciTech Connect

    Mai, T.

    2012-11-01

    This presentation summarizes findings of NREL's Renewable Electricity Futures study, published in June 2012. RE Futures investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050.

  12. Renewable Electricity Futures (Presentation)

    SciTech Connect

    Mai, T.

    2012-10-01

    This presentation library summarizes findings of NREL's Renewable Electricity Futures study, published in June 2012. RE Futures investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050.

  13. Electrical Burns: First Aid

    MedlinePlus

    ... be caused by a number of sources of electricity, such as lightning, stun guns and contact with ... person who has been injured by contact with electricity should be seen by a doctor. Sometimes an ...

  14. Renewable Electricity Futures (Presentation)

    SciTech Connect

    Mai, T.

    2013-04-01

    This presentation summarizes findings of NREL's Renewable Electricity Futures study, published in June 2012. RE Futures investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050.

  15. Ionized Gaseous Nebulae Abundance Determination from the Direct Method

    NASA Astrophysics Data System (ADS)

    Pérez-Montero, Enrique

    2017-04-01

    This tutorial explains the procedure used to analyze an optical emission-line spectrum produced by a nebula ionized by massive star formation. Particularly, the methodology used to derive physical properties, such as electron density and temperature, and the ionic abundances of the most representative elements whose emission lines are present in the optical spectrum is described. The main focus is on the direct method, which is based on the measurement of the electron temperature to derive the abundances, given that the ionization and thermal equilibrium of the ionized gas is dominated by the metallicity. The ionization correction factors used to obtain total abundances from the abundances of some of their ions are also given. Finally, some strong-line methods to derive abundances are described. Such methods are used when no estimation of the temperature can be derived, but which can be consistent with the direct method if they are empirically calibrated.

  16. Three energy variables predict ant abundance at a geographical scale.

    PubMed Central

    Kaspari, M; Alonso, L; O'Donnell, S

    2000-01-01

    Energy theory posits three processes that link local abundance of ectotherms to geographical gradients in temperature. A survey of 49 New World habitats found a two order of magnitude span in the abundance (nests m(-2)) of ground nesting ants (Formicidae). Abundance increased with net primary productivity (r2=0.55), a measure of the baseline supply of harvestable energy. Abundance further increased with mean temperature (r2=0.056), a constraint on foraging activity for this thermophilic taxon. Finally for a given mean temperature, ants were more abundant in seasonal sites with longer, colder winters (r2 = 0.082) that help ectotherm taxa sequester harvested energy in non-productive months. All three variables are currently changing on a global scale. All should be useful in predicting biotic responses to climate change. PMID:10737406

  17. Interstellar Dust Models Consistent with Extinction, Emission, and Abundance Constraints

    NASA Technical Reports Server (NTRS)

    Zubko, Viktor; Dwek, Eli; Arendt, Richard G.

    2004-01-01

    We present new interstellar dust models which have been derived by simultaneously fitting the far ultraviolet to near infrared extinction, the diffuse infrared emission, and, unlike previous models, the elemental abundances in dust for the diffuse interstellar medium. We found that dust models consisting of a mixture of spherical graphite and silicate grains, polycyclic aromatic hydrocarbon (PAH) molecules, in addition to porous composite particles containing silicate, organic refractory, and water ice, provide an improved .t to the UV-to-infrared extinction and infrared emission measurements, while consuming the amounts of elements well within the uncertainties of adopted interstellar abundances, including B star abundances. These models are a signi.cant improvement over the recent Li & Draine (2001, ApJ, 554, 778) model which requires an excessive amount of silicon to be locked up in dust: 48 ppm (atoms per million of H atoms), considerably more than the solar abundance of 34 ppm or the B star abundance of 19 ppm.

  18. Carbon and nitrogen abundances determined from transition layer lines

    NASA Technical Reports Server (NTRS)

    Boehm-Vitense, Erika; Mena-Werth, Jose

    1992-01-01

    The possibility of determining relative carbon, nitrogen, and silicon abundances from the emission-line fluxes in the lower transition layers between stellar chromospheres and coronae is explored. Observations for main-sequence and luminosity class IV stars with presumably solar element abundances show that for the lower transition layers Em = BT sup -gamma. For a given carbon abundance the constants gamma and B in this relation can be determined from the C II and C IV emission-line fluxes. From the N V and S IV lines, the abundances of these elements relative to carbon can be determined from their surface emission-line fluxes. Ratios of N/C abundances determined in this way for some giants and supergiants agree within the limits of errors with those determined from molecular bands. For giants, an increase in the ratio of N/C at B-V of about 0.8 is found, as expected theoretically.

  19. An "Andesitic" Component in Shergottites with Restored LREE Abundances?

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C.-Y.; Wiesmann, H.; Barrat, J. A.

    2002-01-01

    The shergottite Martian meteorites present a variety of oft-confusing petrologic features. In particular, represented among this subgroup are basalts with very depleted LREE abundances, as well as those with nearly chondritic overall REE abundances. The LREE-depleted basalts appear to more closely record the REE and isotopic features of their mantle source legions. Those basalts with more nearly chondritic REE abundances appear to contain an extra component often referred to as a "crustal" component. The addition of the crustal component tends to restore the overall REE abundance pattern towards chondritic relative abundances. Here we suggest that the crustal component could derive from andesitic rocks observed remotely to occur on the Martian surface, and which were analysed at the Pathfinder site.

  20. An "Andestic" Component in Shergottites with Restored LREE Abundances?

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C.-Y.; Wiesmann, H.; Barrat, J. A.

    2002-01-01

    The shergottite Martian meteorites present a variety of oft-confusing petrologic features. In particular, represented among this subgroup are basalts with very depleted LREE abundances, as well as those with nearly chondritic overall REE abundances. The LREE-depleted basalts appear to more closely record the REE and isotopic features of their mantle source regions. Those basalts with more nearly chondritic REE abundances appear to contain an extra component often referred to as a "crustal" component. The addition of the crustal component tends to restore the overall REE abundance pattern towards chondritic relative abundances. Here we suggest that the crustal component could derive from "andesitic" rocks observed remotely to occur on the Martian surface, and which were analysed at the Pathfinder site.

  1. Abundances of the elements in the solar system

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    1973-01-01

    The present status of abundance information for elements in meteorites and in the sun is reviewed, and a new table of abundances of the elements, which should be characteristic of the primitive solar nebula, is compiled and presented. Special attention is called to the elemental abundances in the silicon-to-calcium region, where many of the abundances are rather poorly determined, and where these abundances have an impact on theories of nucleosynthesis of the elements. To each elemental isotope is assigned a mechanism of nucleosynthesis which may have been responsible for production of most of that isotope, and brief comments are made concerning the present status of understanding of the different mechanisms of nucleosynthesis.

  2. Electric Field Imaging Project

    NASA Technical Reports Server (NTRS)

    Wilcutt, Terrence; Hughitt, Brian; Burke, Eric; Generazio, Edward

    2016-01-01

    NDE historically has focused technology development in propagating wave phenomena with little attention to the field of electrostatics and emanating electric fields. This work is intended to bring electrostatic imaging to the forefront of new inspection technologies, and new technologies in general. The specific goals are to specify the electric potential and electric field including the electric field spatial components emanating from, to, and throughout volumes containing objects or in free space.

  3. Electric arc saw apparatus

    DOEpatents

    Deichelbohrer, P.R.

    1983-08-08

    A portable, hand-held electric arc saw apparatus comprising a small frame for supporting an electrically conducting rotary blade which serves as an electrode for generating an electric arc between the blade and a workpiece of opposite polarity. Electrically conducting means are provided on said frame for transmitting current to said blade. A pair of freely movable endless belts in the form of crawler treads are employed to facilitate movement of the apparatus relative to the workpiece.

  4. The lithium abundances of a large sample of red giants

    SciTech Connect

    Liu, Y. J.; Tan, K. F.; Wang, L.; Zhao, G.; Li, H. N.; Sato, Bun'ei; Takeda, Y. E-mail: gzhao@nao.cas.cn

    2014-04-20

    The lithium abundances for 378 G/K giants are derived with non-local thermodynamic equilibrium correction considered. Among these are 23 stars that host planetary systems. The lithium abundance is investigated, as a function of metallicity, effective temperature, and rotational velocity, as well as the impact of a giant planet on G/K giants. The results show that the lithium abundance is a function of metallicity and effective temperature. The lithium abundance has no correlation with rotational velocity at v sin i < 10 km s{sup –1}. Giants with planets present lower lithium abundance and slow rotational velocity (v sin i < 4 km s{sup –1}). Our sample includes three Li-rich G/K giants, 36 Li-normal stars, and 339 Li-depleted stars. The fraction of Li-rich stars in this sample agrees with the general rate of less than 1% in the literature, and the stars that show normal amounts of Li are supposed to possess the same abundance at the current interstellar medium. For the Li-depleted giants, Li-deficiency may have already taken place at the main sequence stage for many intermediate mass (1.5-5 M {sub ☉}) G/K giants. Finally, we present the lithium abundance and kinematic parameters for an enlarged sample of 565 giants using a compilation of the literature, and confirm that the lithium abundance is a function of metallicity and effective temperature. With the enlarged sample, we investigate the differences between the lithium abundance in thin-/thick-disk giants, which indicate that the lithium abundance in thick-disk giants is more depleted than that in thin-disk giants.

  5. Water-evaporation-induced electricity with nanostructured carbon materials.

    PubMed

    Xue, Guobin; Xu, Ying; Ding, Tianpeng; Li, Jia; Yin, Jun; Fei, Wenwen; Cao, Yuanzhi; Yu, Jin; Yuan, Longyan; Gong, Li; Chen, Jian; Deng, Shaozhi; Zhou, Jun; Guo, Wanlin

    2017-01-30

    Water evaporation is a ubiquitous natural process that harvests thermal energy from the ambient environment. It has previously been utilized in a number of applications including the synthesis of nanostructures and the creation of energy-harvesting devices. Here, we show that water evaporation from the surface of a variety of nanostructured carbon materials can be used to generate electricity. We find that evaporation from centimetre-sized carbon black sheets can reliably generate sustained voltages of up to 1 V under ambient conditions. The interaction between the water molecules and the carbon layers and moreover evaporation-induced water flow within the porous carbon sheets are thought to be key to the voltage generation. This approach to electricity generation is related to the traditional streaming potential, which relies on driving ionic solutions through narrow gaps, and the recently reported method of moving ionic solutions across graphene surfaces, but as it exploits the natural process of evaporation and uses cheap carbon black it could offer advantages in the development of practical devices.

  6. Electric Vehicle Technician

    ERIC Educational Resources Information Center

    Moore, Pam

    2011-01-01

    With President Obama's goal to have one million electric vehicles (EV) on the road by 2015, the electric vehicle technician should have a promising and busy future. "The job force in the car industry is ramping up for a revitalized green car industry," according to Greencareersguide.com. An electric vehicle technician will safely troubleshoot and…

  7. Electricity Serves Our Community.

    ERIC Educational Resources Information Center

    Rakow, Steven J., Ed.

    1992-01-01

    Features a color poster entitled "Electricity Serves Our Community" and describes how the poster can be used to help teach about energy, electricity concepts, and types of electrical generation. Explains how teachers can obtain other resources such as posters, lesson plans, and kits from the National Energy Foundation. (PR)

  8. Electric Current Solves Mazes

    ERIC Educational Resources Information Center

    Ayrinhac, Simon

    2014-01-01

    We present in this work a demonstration of the maze-solving problem with electricity. Electric current flowing in a maze as a printed circuit produces Joule heating and the right way is instantaneously revealed with infrared thermal imaging. The basic properties of electric current can be discussed in this context, with this challenging question:…

  9. ELECTRICAL PROPERTIES OF FOODS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foods, especially liquid foods, conduct electricity. Unlike in metals, the charge carriers in foods are ions, instead of electrons. Under normal applications, ions carry the charges as the mass of ions moves along the electrical field. The concentration and mobility of ions determine the electrical ...

  10. Electricity demand curtailment planning

    SciTech Connect

    Allentuck, J; Carroll, O; Schnader, M

    1980-01-01

    The state of electricity demand curtailment planning for long term electricity supply disruptions is reviewed. Legal, institutional and technological problems associated with demand curtailment plans are examined, and the existence of well defined social objectives on the part of planners is questioned. A linear programming approach to electricity demand curtailment planning is presented.

  11. Influence of deer abundance on the abundance of questing adult Ixodes scapularis (Acari: Ixodidae)

    USGS Publications Warehouse

    Ginsberg, H.S.; Zhioua, E.

    1999-01-01

    Nymphal and adult Ixodes scapularis Say were sampled by flagging at 2 sites on a barrier island, Fire Island, NY, and at 2 sites on the nearby mainland. Nymphal densities did not differ consistently between island and mainland sites, but adult densities were consistently lower on the island. We tested whether lower adult densities on the island resulted from greater nymphal mortality on the island than the mainland, or whether adult ticks on the island were poorly sampled by flagging because they had attached abundantly to deer, which were common on Fire Island. Differential nymphal mortality on islands vs. mainland did not explain this difference in adult densities because survival of flat and engorged nymphs in enclosures was the same at island and mainland sites. Ticks were infected by parasitic wasps on the island and not the mainland, but the infection rate (4.3%) was too low to explain the difference in adult tick densities. In contrast, exclusion of deer by game fencing on Fire Island resulted in markedly increased numbers of adult ticks in flagging samples inside compared to samples taken outside the exclosures. Therefore, the scarcity of adult ticks in flagging samples on Fire Island resulted, at least in part, from the ticks being unavailable to flagging samples because they were on deer hosts. Differences in the densities of flagged ticks inside and outside the exclosures were used to estimate the percentage of questing adults on Fire Island that found deer hosts, excluding those that attached to other host species. Approximately 56% of these questing adult ticks found deer hosts in 1995 and 50% found deer hosts in 1996. Therefore, in areas where vertebrate hosts are highly abundant, large proportions of the questing tick population can find hosts. Moreover, comparisons of tick densities at different sites by flagging can potentially be biased by differences in host densities among sites.

  12. Electric car arrives - again

    SciTech Connect

    Dunn, S.

    1997-03-01

    The first mass-produced electric cars in modern times are here, although they are expensive, limited in capability and unfamiliar to most prospective consumers. This article presents a brief history of the reintroduction of the modern electric car as well as discussions of the limitations of development, alternative routes to both producing and selling electric cars or some modified version of electric cars, economic incentives and governmental policies, and finally a snapshot description of the future for electric cars. 6 refs., 1 tab.

  13. Unexpected spatiotemporal abundance of infected Culex restuans suggest a greater role as a West Nile virus vector for this native species.

    PubMed

    Johnson, Brian J; Robson, Mark G; Fonseca, Dina M

    2015-04-01

    Difficulties in correctly differentiating Culex restuans mosquitoes from Culex pipiens have left the spatiotemporal mechanisms underlying the epidemiology of West Nile virus (WNV) in the northeastern United States largely unresolved. We performed weekly surveys across a natural to urban gradient of sites in central New Jersey (USA) and used a rapid and cheap DNA extraction and a species-specific PCR assay to create single species pools for WNV testing. To assess seasonal trends we combined these results with WNV surveillance records generated from grouped Cx. restuans/Cx. pipiens pools tested in 2011-2012. Cx.restuans was found to be highly abundant within all sites and reached especially high abundance in urban wetland habitats greatly disturbed by human action. In contrast, the seasonal presence of Cx. pipiens was greatest in residential and urban habitats and its presence in natural areas was minimal throughout the season. WNV infection rates in both species were similar but Cx. restuans was consistently found infected first and more frequently, even as early as May, whereas WNV was first detected in Cx. pipiens in late July. WNV activity peaked during the month of August when WNV was commonly isolated from both species. The peak in WNV activity in August observed for both species was consistent with data from 2011 to 2012 when Cx. restuans and Cx. pipiens were grouped, although analyzing single species pools increased overall predicted infection levels. Our results support the preeminence of Cx. restuans as an enzootic vector of WNV and strongly suggest this species has become a "native invasive" exploiting human modified habitats and reaching very high abundance there. Importantly, high infection rates in disturbed wetland sites with high populations of Cx. restuans suggest this species may enable the introduction of WNV to urbanized environments where both Culex contribute to transmission potentiating disease risk.

  14. Geographical Range and Local Abundance of Tree Species in China

    PubMed Central

    Ren, Haibao; Condit, Richard; Chen, Bin; Mi, Xiangcheng; Cao, Min; Ye, Wanhui; Hao, Zhanqing; Ma, Keping

    2013-01-01

    Most studies on the geographical distribution of species have utilized a few well-known taxa in Europe and North America, with little research in China and its wide range of climate and forest types. We assembled large datasets to quantify the geographic ranges of tree species in China and to test several biogeographic hypotheses: 1) whether locally abundant species tend to be geographically widespread; 2) whether species are more abundant towards their range-centers; and 3) how abundances are correlated between sites. Local abundances of 651 species were derived from four tree plots of 20–25 ha where all individuals ≥1 cm in stem diameter were mapped and identified taxonomically. Range sizes of these species across China were then estimated from over 460,000 geo-referenced records; a Bayesian approach was used, allowing careful measures of error of each range estimate. The log-transformed range sizes had a bell-shaped distribution with a median of 703,000 km2, and >90% of 651 species had ranges >105 km2. There was no relationship between local abundance and range size, and no evidence for species being more abundant towards their range-centers. Finally, species’ abundances were positively correlated between sites. The widespread nature of most tree species in China suggests few are vulnerable to global extinction, and there is no indication of the double-peril that would result if rare species also had narrow ranges. PMID:24130772

  15. A Semi-automated Abundance Survey of Ap Stars

    NASA Astrophysics Data System (ADS)

    Hall, Martin P.; Kurtz, Don; Elkin, Vladimir; Bruntt, Hans

    2015-08-01

    We have carried out an abundance analysis on the high-resolution spectra of approximately 350 Ap stars collected between 2007 and 2010 on the FEROS Echelle (Fibre-led, Extended Range, Echelle ) spectrograph housed at the 2.2-m telescope at European Southern Observatory at La Silla, Chile. We employed the VWA package (vsin I, wavelength shift, abundance analysis) for preliminary selection of spectral lines, and a semi-automated set of routines which we developed in the programming language IDL, to calculate the equivalent widths and abundances of ions of Iron and the rare earth elements Neodymium and Praseodymium using the WIDTH program and NEMO model atmospheres. Initial results are presented, which reinforce the correlation between iron abundance and effective temperature, from an over-abundance in the late Bp stars, to under-abundant in the early F stars. Results also suggest that the disequilibrium in abundances of the first and second ionisation stages of these ions in the rapidly oscillating Ap (roAp) stars may a consequence of the relatively cool temperatures of those stars, rather than a signature of pulsation.

  16. Dam removal increases American eel abundance in distant headwater streams

    USGS Publications Warehouse

    Hitt, Nathaniel P.; Eyler, Sheila; Wofford, John E.B.

    2012-01-01

    American eel Anguilla rostrata abundances have undergone significant declines over the last 50 years, and migration barriers have been recognized as a contributing cause. We evaluated eel abundances in headwater streams of Shenandoah National Park, Virginia, to compare sites before and after the removal of a large downstream dam in 2004 (Embrey Dam, Rappahannock River). Eel abundances in headwater streams increased significantly after the removal of Embrey Dam. Observed eel abundances after dam removal exceeded predictions derived from autoregressive models parameterized with data prior to dam removal. Mann–Kendall analyses also revealed consistent increases in eel abundances from 2004 to 2010 but inconsistent temporal trends before dam removal. Increasing eel numbers could not be attributed to changes in local physical habitat (i.e., mean stream depth or substrate size) or regional population dynamics (i.e., abundances in Maryland streams or Virginia estuaries). Dam removal was associated with decreasing minimum eel lengths in headwater streams, suggesting that the dam previously impeded migration of many small-bodied individuals (<300 mm TL). We hypothesize that restoring connectivity to headwater streams could increase eel population growth rates by increasing female eel numbers and fecundity. This study demonstrated that dams may influence eel abundances in headwater streams up to 150 river kilometers distant, and that dam removal may provide benefits for eel management and conservation at the landscape scale.

  17. OH Column Abundance Apparent Response to Solar Cycle 23

    NASA Astrophysics Data System (ADS)

    Burnett, C. R.; Minschwaner, K. R.

    2009-12-01

    The 33-year series of high spectral resolution measurements of absorption of sunlight by OH at 308 nm has exhibited temporary decreases of column abundances in 1986, 1997, and 2008 near the times of minimum solar activity. These observations and analyses are of significance as they encompass three complete solar cycles for comparison. During solar cycle 23, the annual average abundances increased approximately 20% from the minimum abundance in 1997 to high-sun enhanced values in 2000-2006, then dropped approximately 15% in 2008. The abundances exhibited a pronounced reduction at solar minimum in August-October 2008, similar to that seen in fall 1986 and fall 1997. The average morning abundances on those occasions were 13% smaller than the 1980-88 corresponding average, about 0.9 x 1013 cm-2, with minimum values broadly consistent with model results. In contrast, high-sun OH abundances observed during periods of solar maximum are approximately 33% larger than modeled abundances. This discrepancy cannot be explained by reasonable adjustments of reaction rates or modeled constituent concentrations in the stratosphere or mesosphere. However, the observed responses to a tropopause fold event in 1988 and to the Pinatubo aerosol in 1991 do suggest an important contribution to the total OH column from the lower stratosphere. In addition to the apparent variations with solar activity, this OH column database contains a number of other effects such as diurnal and seasonal patterns, and geographic differences between observations from Colorado, Florida, Alaska, Micronesia, New Zealand, and New Mexico.

  18. (Un)true deuterium abundance in the Galactic disk

    NASA Astrophysics Data System (ADS)

    Prodanović, Tijana; Steigman, Gary; Fields, Brian D.

    2010-04-01

    Deuterium has a special place in cosmology, nuclear astrophysics, and galactic chemical evolution, because of its unique property that it is only created in the big bang nucleosynthesis while all other processes result in its net destruction. For this reason, among other things, deuterium abundance measurements in the interstellar medium (ISM) allow us to determine the fraction of interstellar gas that has been cycled through stars, and set constraints and learn about different Galactic chemical evolution (GCE) models. However, recent indications that deuterium might be preferentially depleted onto dust grains complicate our understanding about the meaning of measured ISM deuterium abundances. For this reason, recent estimates by Linsky et al. (2006) have yielded a lower bound to the “true”, undepleted, ISM deuterium abundance that is very close to the primordial abundance, indicating a small deuterium astration factor contrary to the demands of many GCE models. To avoid any prejudice about deuterium dust depletion along different lines of sight that are used to determine the “true” D abundance, we propose a model-independent, statistical Bayesian method to address this issue and determine in a model-independent manner the undepleted ISM D abundance. We find the best estimate for the gas-phase ISM deuterium abundance to be (D/H)ISM ≥ (2.0 ± 0.1) × 10-5. Presented are the results of Prodanović et al. (2009).

  19. Stellar abundances in the solar neighborhood: The Hypatia Catalog

    SciTech Connect

    Hinkel, Natalie R.; Timmes, F.X.; Young, Patrick A.; Pagano, Michael D.; Turnbull, Margaret C.

    2014-09-01

    We compile spectroscopic abundance data from 84 literature sources for 50 elements across 3058 stars in the solar neighborhood, within 150 pc of the Sun, to produce the Hypatia Catalog. We evaluate the variability of the spread in abundance measurements reported for the same star by different surveys. We also explore the likely association of the star within the Galactic disk, the corresponding observation and abundance determination methods for all catalogs in Hypatia, the influence of specific catalogs on the overall abundance trends, and the effect of normalizing all abundances to the same solar scale. The resulting stellar abundance determinations in the Hypatia Catalog are analyzed only for thin-disk stars with observations that are consistent between literature sources. As a result of our large data set, we find that the stars in the solar neighborhood may reveal an asymmetric abundance distribution, such that a [Fe/H]-rich group near the midplane is deficient in Mg, Si, S, Ca, Sc II, Cr II, and Ni as compared to stars farther from the plane. The Hypatia Catalog has a wide number of applications, including exoplanet hosts, thick- and thin-disk stars, and stars with different kinematic properties.

  20. Seasonal Abundance of Aphids and Aphidophagous Insects in Pecan.

    PubMed

    Dutcher, James D; Karar, Haider; Abbas, Ghulam

    2012-12-05

    Seasonal occurrence of aphids and aphidophagous insects was monitored for six years (2006-2011) from full leaf expansion in May to leaf fall in October in "Desirable" variety pecan trees that were not treated with insecticides. Aphid outbreaks occurred two times per season, once in the spring and again in the late summer. Yellow pecan and blackmargined aphids exceeded the recommended treatment thresholds one time and black pecan aphids exceeded the recommended treatment levels three times over the six seasons. Increases in aphidophagous insect abundance coincided with aphid outbreaks in five of the six seasons. Among aphidophagous insects Harmonia axyridis and Olla v-nigrum were frequently collected in both the tree canopy and at the ground level, whereas, Coccinella septempunctata, Hippodamia convergens were rarely found in the tree canopy and commonly found at the ground level. Green lacewing abundance was higher in the ground level than in the tree canopy. Brown lacewings were more abundant in the tree canopy than at the ground level. Dolichopodid and syrphid fly abundance, at the ground level increased during peak aphid abundance in the tree canopy. Application of an aqueous solution of fermenting molasses to the pecan foliage during an aphid outbreak significantly increased the abundance of ladybeetles and lacewings and significantly reduced the abundance of yellow pecan, blackmargined and black pecan aphids.

  1. Geographical range and local abundance of tree species in China.

    PubMed

    Ren, Haibao; Condit, Richard; Chen, Bin; Mi, Xiangcheng; Cao, Min; Ye, Wanhui; Hao, Zhanqing; Ma, Keping

    2013-01-01

    Most studies on the geographical distribution of species have utilized a few well-known taxa in Europe and North America, with little research in China and its wide range of climate and forest types. We assembled large datasets to quantify the geographic ranges of tree species in China and to test several biogeographic hypotheses: 1) whether locally abundant species tend to be geographically widespread; 2) whether species are more abundant towards their range-centers; and 3) how abundances are correlated between sites. Local abundances of 651 species were derived from four tree plots of 20-25 ha where all individuals ≥1 cm in stem diameter were mapped and identified taxonomically. Range sizes of these species across China were then estimated from over 460,000 geo-referenced records; a Bayesian approach was used, allowing careful measures of error of each range estimate. The log-transformed range sizes had a bell-shaped distribution with a median of 703,000 km(2), and >90% of 651 species had ranges >10(5) km(2). There was no relationship between local abundance and range size, and no evidence for species being more abundant towards their range-centers. Finally, species' abundances were positively correlated between sites. The widespread nature of most tree species in China suggests few are vulnerable to global extinction, and there is no indication of the double-peril that would result if rare species also had narrow ranges.

  2. Implications of Abundant Gas and Oil for Climate Forcing

    NASA Astrophysics Data System (ADS)

    Edmonds, J.

    2015-12-01

    Perhaps the most important development in the field of energy over the past decade has been the advent of technologies that enable the production of larger volumes of natural gas and oil at lower cost. The availability of more abundant gas and oil is reshaping the global energy system, with implications for both evolving emissions of CO2 and other climate forcers. More abundant gas and oil will also transform the character of greenhouse gas emissions mitigation. We review recent findings regarding the impact of abundant gas and oil for climate forcing and the challenge of emissions mitigation. We find strong evidence that, absent policies to limits its penetration against renewable energy, abundant gas has little observable impact on CO2 emissions, and tends to increase overall climate forcing, though the latter finding is subject to substantial uncertainty. The presence of abundant gas also affects emissions mitigation. There is relatively little literature exploring the implication of expanded gas availability on the difficulty in meeting emissions mitigation goals. However, preliminary results indicate that on global scales abundant gas does not substantially affect the cost of emissions mitigation, even though natural gas could have an expanded role in emissions mitigation scenarios as compared with scenarios in which natural gas is less abundant.

  3. Aggregative response in bats: prey abundance versus habitat.

    PubMed

    Müller, Jörg; Mehr, Milenka; Bässler, Claus; Fenton, M Brock; Hothorn, Torsten; Pretzsch, Hans; Klemmt, Hans-Joachim; Brandl, Roland

    2012-07-01

    In habitats where prey is either rare or difficult to predict spatiotemporally, such as open habitats, predators must be adapted to react effectively to variations in prey abundance. Open-habitat foraging bats have a wing morphology adapted for covering long distances, possibly use information transfer to locate patches of high prey abundance, and would therefore be expected to show an aggregative response at these patches. Here, we examined the effects of prey abundance on foraging activities of open-habitat foragers in comparison to that of edge-habitat foragers and closed-habitat foragers. Bat activity was estimated by counting foraging calls recorded with bat call recorders (38,371 calls). Prey abundance was estimated concurrently at each site using light and pitfall traps. The habitat was characterized by terrestrial laser scanning. Prey abundance increased with vegetation density. As expected, recordings of open-habitat foragers clearly decreased with increasing vegetation density. The foraging activity of edge- and closed-habitat foragers was not significantly affected by the vegetation density, i.e., these guilds were able to forage from open habitats to habitats with dense vegetation. Only open-habitat foragers displayed a significant and proportional aggregative response to increasing prey abundance. Our results suggest that adaptations for effective and low-cost foraging constrains habitat use and excludes the guild of open-habitat foragers from foraging in habitats with high prey abundance, such as dense forest stands.

  4. A revised DDO abundance calibration for population I red giants

    NASA Astrophysics Data System (ADS)

    Piatti, A. E.; Claria, J. J.; Minniti, D.

    1993-12-01

    Several arguments that justify establishing a revised abundance calibration for DDO photometry of population I red giants are presented. The components of the blanketing vector in the DDO C(45-48) vs C(42-45) diagram are determined for late-type dwarfs and giants. We have redefined the DDO cyanogen anomaly and calibrated it against metallicity. The sample of field giants now available with abundances derived from high dispersion spectroscopy is substantially larger than previously available, leading to a more accurate abundance calibration. Iso-abundance lines in the C(41-42) vs C(42-45) diagram have been determined for population IG and K giants and an iterative method for deriving abundances of these stars is described. We show that the new DDO abundances are in very good agreement with those derived from high dispersion spectroscopy. The new method improves by about 0.1 dex the DDO abundances derived for early G and/or late K giants, with respect to the delta(CN) method of Janes (1975).

  5. Model reduction for stochastic chemical systems with abundant species.

    PubMed

    Smith, Stephen; Cianci, Claudia; Grima, Ramon

    2015-12-07

    Biochemical processes typically involve many chemical species, some in abundance and some in low molecule numbers. We first identify the rate constant limits under which the concentrations of a given set of species will tend to infinity (the abundant species) while the concentrations of all other species remains constant (the non-abundant species). Subsequently, we prove that, in this limit, the fluctuations in the molecule numbers of non-abundant species are accurately described by a hybrid stochastic description consisting of a chemical master equation coupled to deterministic rate equations. This is a reduced description when compared to the conventional chemical master equation which describes the fluctuations in both abundant and non-abundant species. We show that the reduced master equation can be solved exactly for a number of biochemical networks involving gene expression and enzyme catalysis, whose conventional chemical master equation description is analytically impenetrable. We use the linear noise approximation to obtain approximate expressions for the difference between the variance of fluctuations in the non-abundant species as predicted by the hybrid approach and by the conventional chemical master equation. Furthermore, we show that surprisingly, irrespective of any separation in the mean molecule numbers of various species, the conventional and hybrid master equations exactly agree for a class of chemical systems.

  6. Model reduction for stochastic chemical systems with abundant species

    SciTech Connect

    Smith, Stephen; Cianci, Claudia; Grima, Ramon

    2015-12-07

    Biochemical processes typically involve many chemical species, some in abundance and some in low molecule numbers. We first identify the rate constant limits under which the concentrations of a given set of species will tend to infinity (the abundant species) while the concentrations of all other species remains constant (the non-abundant species). Subsequently, we prove that, in this limit, the fluctuations in the molecule numbers of non-abundant species are accurately described by a hybrid stochastic description consisting of a chemical master equation coupled to deterministic rate equations. This is a reduced description when compared to the conventional chemical master equation which describes the fluctuations in both abundant and non-abundant species. We show that the reduced master equation can be solved exactly for a number of biochemical networks involving gene expression and enzyme catalysis, whose conventional chemical master equation description is analytically impenetrable. We use the linear noise approximation to obtain approximate expressions for the difference between the variance of fluctuations in the non-abundant species as predicted by the hybrid approach and by the conventional chemical master equation. Furthermore, we show that surprisingly, irrespective of any separation in the mean molecule numbers of various species, the conventional and hybrid master equations exactly agree for a class of chemical systems.

  7. Electrical Equipment of Electrical Stations and Substations,

    DTIC Science & Technology

    1979-10-25

    possibility of the conversion of industry on the new, more advanced energy base . Thre-e-phasp current proved to be technically and economically more... energy up to large distances it was difficultly make as a result of the large heat losses in conduits/manifolds, then heat and power plants were...transmitted by the wires of smaller sections. Decrease energy losses in electric system. Since electric generators and receivers are constructed to the

  8. How Ants Drop Out: Ant Abundance on Tropical Mountains

    PubMed Central

    Longino, John T.; Branstetter, Michael G.; Colwell, Robert K.

    2014-01-01

    In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica) and examined the impact of elevation (as a proxy for temperature) and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops. PMID:25098722

  9. High chemical abundances in stripped Virgo spiral galaxies

    NASA Astrophysics Data System (ADS)

    Skillman, E. D.; Kennicutt, R. C.; Shields, G. A.

    1993-01-01

    Based on a comparison of the oxygen abundances in H 2 regions in field and Virgo cluster late type spiral galaxies, Shields, Skillman, & Kennicutt (1991) suggested that the highly stripped spiral galaxies in the Virgo cluster have systematically higher abundances than comparable field galaxies. In April 1991 and May 1992 we used the blue channel spectrograph on the MMT to obtain new observations of 30 H 2 regions in Virgo spiral galaxies. These spectra cover the wavelength range from (O II) lambda 3727 to (S II) lambda 6731. We now have observed at least 4 H II regions in 9 spiral galaxies in the Virgo cluster. Combining (O II) and (O III) line strengths, we calculate the H II region oxygen abundances based on the empirical calibration of Edmunds & Pagel (1984). These observations show: (1) The stripped, low luminosity Virgo spirals (N4689, N4571) truly have abundances characteristic of much more luminous field spirals; (2) Virgo spirals which show no evidence of stripping (N4651, N4713) have abundances comparable to field galaxies; and (3) Evidence for transition galaxies (e.g., N4254, N4321), with marginally stripped disks and marginal abundance enhancements. The new observations presented here confirm the validity of the oxygen over-abundances in the stripped Virgo spirals. Shields et al. (1991) discussed two different mechanisms for producing the higher abundances in the disks of stripped galaxies in Virgo. The first is the supression of infall of near-primordial material, the second is the suppression of radial inflow of metal-poor gas. Distinguishing between the two cases will require more observations of the Virgo cluster spirals and a better understanding of which parameters determine the variation of abundance with radius in field spirals (cf., Garnett & Shields 1987).

  10. Understanding and reducing statistical uncertainties in nebular abundance determinations

    NASA Astrophysics Data System (ADS)

    Wesson, R.; Stock, D. J.; Scicluna, P.

    2012-06-01

    Whenever observations are compared to theories, an estimate of the uncertainties associated with the observations is vital if the comparison is to be meaningful. However, many or even most determinations of temperatures, densities and abundances in photoionized nebulae do not quote the associated uncertainty. Those that do typically propagate the uncertainties using analytical techniques which rely on assumptions that generally do not hold. Motivated by this issue, we have developed Nebular Empirical Analysis Tool (NEAT), a new code for calculating chemical abundances in photoionized nebulae. The code carries out a standard analysis of lists of emission lines using long-established techniques to estimate the amount of interstellar extinction, calculate representative temperatures and densities, compute ionic abundances from both collisionally excited lines and recombination lines, and finally to estimate total elemental abundances using an ionization correction scheme. NEATuses a Monte Carlo technique to robustly propagate uncertainties from line flux measurements through to the derived abundances. We show that, for typical observational data, this approach is superior to analytic estimates of uncertainties. NEAT also accounts for the effect of upward biasing on measurements of lines with low signal-to-noise ratio, allowing us to accurately quantify the effect of this bias on abundance determinations. We find not only that the effect can result in significant overestimates of heavy element abundances derived from weak lines, but also that taking it into account reduces the uncertainty of these abundance determinations. Finally, we investigate the effect of possible uncertainties in R, the ratio of selective-to-total extinction, on abundance determinations. We find that the uncertainty due to this parameter is negligible compared to the statistical uncertainties due to typical line flux measurement uncertainties.

  11. Economics of electricity

    NASA Astrophysics Data System (ADS)

    Erdmann, G.

    2015-08-01

    The following text is an introduction into the economic theory of electricity supply and demand. The basic approach of economics has to reflect the physical peculiarities of electric power that is based on the directed movement of electrons from the minus pole to the plus pole of a voltage source. The regular grid supply of electricity is characterized by a largely constant frequency and voltage. Thus, from a physical point of view electricity is a homogeneous product. But from an economic point of view, electricity is not homogeneous. Wholesale electricity prices show significant fluctuations over time and between regions, because this product is not storable (in relevant quantities) and there may be bottlenecks in the transmission and distribution grids. The associated non-homogeneity is the starting point of the economic analysis of electricity markets.

  12. Plant electrical memory.

    PubMed

    Volkov, Alexander G; Carrell, Holly; Adesina, Tejumade; Markin, Vladislav S; Jovanov, Emil

    2008-07-01

    Electrical signaling, short-term memory and rapid closure of the carnivorous plant Dionaea muscipula Ellis (Venus flytrap) have been attracting the attention of researchers since the XIX century. We found that the electrical stimulus between a midrib and a lobe closes the Venus flytrap upper leaf without mechanical stimulation of trigger hairs. The closing time of Venus flytrap by electrical stimulation is the same as mechanically induced closing. Transmission of a single electrical charge between a lobe and the midrib causes closure of the trap and induces an electrical signal propagating between both lobes and midrib. The Venus flytrap can accumulate small subthreshold charges, and when the threshold value is reached, the trap closes. Repeated application of smaller charges demonstrates the summation of stimuli. The cumulative character of electrical stimuli points to the existence of short-term electrical memory in the Venus flytrap.

  13. Short-scale variations of the solar wind helium abundance

    SciTech Connect

    Šafránková, J.; Němeček, Z.; Cagaš, P.; Přech, L.; Pavlů, J.; Zastenker, G. N.; Riazantseva, M. O.; Koloskova, I. V.

    2013-11-20

    Abrupt changes of the relative He abundance in the solar wind are usually attributed to encounters with boundaries dividing solar wind streams from different sources in the solar corona. This paper presents a systematic study of fast variations of the He abundance that supports the idea that a majority of these variations on short timescales (3-30 s) are generated by in-transit turbulence that is probably driven by the speed difference between the ion species. This turbulence contributes to the solar wind heating and leads to a correlation of the temperature with He abundance.

  14. Chemical evolution models for NGC 6822 using planetary nebulae abundances

    NASA Astrophysics Data System (ADS)

    Hernández-Martínez, Liliana; Carigi, Leticia; Peña, Miriam; Peimbert, Manuel

    2012-08-01

    We present chemical evolution models for the dwarf irregular NGC 6822, using chemical abundances of Planetary Nebulae (PNe) and HII regions and also the mass of gas (M gas ) as observational constraints. Chemical evolution models have been calculated to reproduce the abundances as derived from both, collisionally excited lines (CELs) and recombination lines (RLs). In our models, the chemical contribution of low and intermediate mass stars (LIMS) is time delayed, while for the massive stars the chemical contribution is instantaneous, as in Franco & Carigi (2008). The chemical contribution of SNIa is included in our model, thus we are also able to reproduce the observational Fe/H abundance obtained from A stars.

  15. On the abundance of Europium. [in Ap and Am stars

    NASA Technical Reports Server (NTRS)

    Hartoog, M. R.; Cowley, C. R.; Adelman, S. J.

    1974-01-01

    The inclusion of the effects of hyperfine splitting can significantly lower the abundance estimate of Eu from singly ionized lines which lie on the flat portion of the curve of growth. In the 21 cool Ap stars studied by Adelman and the five Am stars studied by Smith, the Eu abundance was reduced by 0.4 dex on the average. In individual cases, the reductions were as great as 0.9 dex. This makes the Eu abundance comparable to that of its neighboring rare earths Sm and Gd in the Ap stars and less than Sm and Gd in the Am stars, but still substantially overabundant with respect to solar values.

  16. Trace-element abundances in several new ureilites

    NASA Technical Reports Server (NTRS)

    Boynton, William V.; Hill, Dolores H.

    1993-01-01

    Four new ureilites are analyzed for trace-element abundances. Frontier Mountain (FRO) 90054 is an augite-rich ureilite and has high rare earth element (REE) abundances with a pattern expected of augite. FRO 90036 and Acfer 277 have REE patterns similar to the V-shape pattern of other ureilites. Nuevo Mercurio (b) has very high REE abundances, but they look like they are due to terrestrial alteration. The siderophile-element pattern of these ureilites are similar to those of known ureilites.

  17. Ecological niche structure and rangewide abundance patterns of species

    PubMed Central

    Martínez-Meyer, Enrique; Díaz-Porras, Daniel; Peterson, A. Townsend; Yáñez-Arenas, Carlos

    2013-01-01

    Spatial abundance patterns across species' ranges have attracted intense attention in macroecology and biogeography. One key hypothesis has been that abundance declines with geographical distance from the range centre, but tests of this idea have shown that the effect may occur indeed only in a minority of cases. We explore an alternative hypothesis: that species' abundances decline with distance from the centroid of the species' habitable conditions in environmental space (the ecological niche). We demonstrate consistent negative abundance–ecological distance relationships across all 11 species analysed (turtles to wolves), and that relationships in environmental space are consistently stronger than relationships in geographical space. PMID:23134784

  18. The determination of electron abundances in interstellar clouds

    NASA Technical Reports Server (NTRS)

    Wootten, A.; Snell, R.; Glassgold, A. E.

    1979-01-01

    An independent method is proposed for the determination of electron abundances in dense clouds based upon the abundance ratio of HCO(+) and CO. The method is derived from a simple application of gas phase ion molecule interstellar chemistry. It is noted that unlike the fractionation of deuterated molecules, it applies to warm as well as to cool clouds. The method is illustrated with the results of the recent abundance survey of Wooten et al. (1978). Finally, it is shown that in cases where deuterium enhancement is measured, an upper limit can be obtained for the cosmic ray ionization rate.

  19. An Elementary Treatise on Electricity

    NASA Astrophysics Data System (ADS)

    Clerk Maxwell, James; Garnett, William

    2011-06-01

    Editor's preface; Fragment of author's preface; 1. Experiment 1; 2. On the charges of electrified bodies; 3. On electrical work and energy; 4. The electric field; 5. Faraday's law of lines of induction; 6. Particular cases of electrification; 7. Electrical images; 8. Capacity; 9. Electric current; 10. Phenomena of an electric current which flows through heterogeneous media; 11. Methods of maintaining an electric current; 12. On the measurement of electric resistance; 13. On the electric resistance of substances.

  20. Electricity Market Module - NEMS Documentation

    EIA Publications

    2014-01-01

    Documents the Electricity Market Module as it was used for the Annual Energy Outlook 2013. The Electricity Market Module (EMM) is the electricity supply component of the National Energy Modeling System (NEMS). The EMM represents the generation, transmission, and pricing of electricity. It consists of four submodules: the Electricity Capacity Planning (ECP) Submodule, the Electricity Fuel Dispatch (EFD) Submodule, the Electricity Finance and Pricing (EFP) Submodule, and the Electricity Load and Demand (ELD) Submodule.

  1. The millimeter-wave spectrum of AlOH. [in relevance to its high cosmic abundance

    NASA Technical Reports Server (NTRS)

    Apponi, A. J.; Barclay, W. L., Jr.; Ziurys, L. M.

    1993-01-01

    The pure rotational spectrum of the AlOH and AlOD molecules in their X 1Sigma(+) (v = 0) ground electric states has been measured in the laboratory using direct absorption millimeter/submillimeter spectroscopy. The species were produced by the reaction of aluminum vapor, created in a Broida-type oven, with hydrogen peroxide or D2O2. Eight rotational transitions of AlOH and five transitions for AlOD were measured in the frequency range of 157-378 GHz to an accuracy better than +/- 75 kHz. Electric quadrupole interactions, arising from the aluminum nuclear spin of 5/2, were observed in the J = 4 - 5 and the J = 5 - 6 transitions of AlOH. The rotational constants of these molecules have been determined from a nonlinear least-squares fit to the data. The electric quadrupole coupling constant, eqQ, has been measured as well, and was found to have a value of -42.4 +/- 4.3 MHz. The spectra are consistent with quasi-linear ground states for AlOH and AlOD, as predicted by theory. AlOH is of astrophysical interest because of the relatively high cosmic abundance of aluminum.

  2. Coronal element abundances derived from solar energetic particles

    NASA Technical Reports Server (NTRS)

    Reames, Donald V.

    1994-01-01

    The large gradual solar-energetic-particle (SEP) events, where abundances are commonly measured, are produced when coronal mass ejections (CMEs) drive shock waves through the corona and the interplanetary medium. The shock accelerates particles from the highly-ionized, approximately 1.5 MK, plasma in a manner that depends only weakly upon the Q/A of the ion, except at very high energies. Averaging the approximately 1 MeV/amu abundances over many events compensates for the acceleration effects to produce abundances that appear to correspond directly to those in the coronal source for all observed elements, including H. The resulting abundances reflect the 4 x enhancement of ions with low values of first ionization potential (FIP) arising from ion-neutral fractionation that occurs as the atoms are transported up from the photosphere. A different pattern of fractionation is found for ions that are shock-accelerated from the high speed solar wind emerging from coronal holes.

  3. Relative abundance of desert tortoises on the Nevada Test Site

    SciTech Connect

    Rautenstrauch, K.R.; O`Farrell, T.P.

    1993-12-31

    Seven hundred fifty-nine transects having a total length of 1,191 km were walked during 1981--1986 to determine the distribution and relative abundance of desert tortoises (Gopherus agassizii) on the Nevada Test Site (NTS). The abundance of tortoises on NTS was low to very low relative to other populations in the Mojave Desert. Sign of tortoises was found from 880 to 1,570 m elevation and was more abundant above 1,200 m than has been reported previously for Nevada. Tortoises were more abundant on NTS on the upper alluvial fans and slopes of mountains than in valley bottoms. They also were more common on or near limestone and dolomite mountains than on mountains of volcanic origin.

  4. THE ATOMIC WEIGHTS COMMISSION AND ISOTOPIC ABUNDANCE RATIO DETERMINATIONS.

    SciTech Connect

    HOLDEN, N.E.

    2005-08-07

    Following Thomson's discovery of stable isotopes in non-radioactive chemical elements, the derivation of atomic weight values from mass spectrometric measurements of isotopic abundance ratios moved very slowly. Forty years later, only 3 1/2 % of the recommended values were based on mass spectrometric measurements and only 38% in the first half century. It might be noted that two chemical elements (tellurium and mercury) are still based on chemical measurements, where the atomic weight value calculated from the relative isotopic abundance measurement either agrees with the value from the chemical measurement or the atomic weight value calculated from the relative isotopic abundance measurement falls within the uncertainty of the chemical measurement of the atomic weight. Of the 19 chemical elements, whose atomic weight is based on non-corrected relative isotopic abundance measurements, five of these are two isotope systems (indium, iridium, lanthanum, lutetium and tantalum) and one is a three-isotope system (oxygen).

  5. Why abundant tropical tree species are phylogenetically old.

    PubMed

    Wang, Shaopeng; Chen, Anping; Fang, Jingyun; Pacala, Stephen W

    2013-10-01

    Neutral models of species diversity predict patterns of abundance for communities in which all individuals are ecologically equivalent. These models were originally developed for Panamanian trees and successfully reproduce observed distributions of abundance. Neutral models also make macroevolutionary predictions that have rarely been evaluated or tested. Here we show that neutral models predict a humped or flat relationship between species age and population size. In contrast, ages and abundances of tree species in the Panamanian Canal watershed are found to be positively correlated, which falsifies the models. Speciation rates vary among phylogenetic lineages and are partially heritable from mother to daughter species. Variable speciation rates in an otherwise neutral model lead to a demographic advantage for species with low speciation rate. This demographic advantage results in a positive correlation between species age and abundance, as found in the Panamanian tropical forest community.

  6. Oxygen and nitrogen abundances in Virgo and field spirals

    NASA Astrophysics Data System (ADS)

    Pilyugin, L. S.; Mollá, M.; Ferrini, F.; Vílchez, J. M.

    2002-01-01

    The oxygen and nitrogen abundances in the H II regions of the nine Virgo spirals of the sample from Skillman et al. (1996) and in nine field spiral galaxies are re-determined with the recently suggested P-method. We confirm that there is an abundance segregation in the sample of Virgo spirals in the sense that the H I deficient Virgo spirals near the core of the cluster have higher oxygen abundances in comparison to the spirals at the periphery of the Virgo cluster. At the same time both the Virgo periphery and core spirals have counterparts among field spirals. Some field spirals have H I to optical radius ratios, similar to that in H I deficient Virgo core spirals. We conclude that if there is a difference in the abundance properties of the Virgo and field spirals, this difference appears to be small and masked by the observational errors.

  7. Abundance of Asymmetric Dark Matter in Brane World Cosmology

    NASA Astrophysics Data System (ADS)

    Abdusattar, Haximjan; Iminniyaz, Hoernisa

    2016-09-01

    Relic abundance of asymmetric Dark Matter particles in brane world cosmological scenario is investigated in this article. Hubble expansion rate is enhanced in brane world cosmology and it affects the relic abundance of asymmetric Dark Matter particles. We analyze how the relic abundance of asymmetric Dark Matter is changed in this model. We show that in such kind of nonstandard cosmological scenario, indirect detection of asymmetric Dark Matter is possible if the cross section is small enough which let the anti-particle abundance kept in the same amount with the particle. We show the indirect detection signal constraints can be used to such model only when the cross section and the 5-dimensional Planck mass scale are in appropriate values. Supported by the National Natural Science Foundation of China under Grant No. 11365022

  8. Dark Energy and The Dark Matter Relic Abundance

    SciTech Connect

    Rosati, Francesca

    2004-11-17

    Two mechanisms by which the quintessence scalar could enhance the relic abundance of dark matter particles are discussed. These effects can have an impact on supersymmetric candidates for dark matter.

  9. A SOLAR SPECTROSCOPIC ABSOLUTE ABUNDANCE OF ARGON FROM RESIK

    SciTech Connect

    Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Kuznetsov, V. D. E-mail: kjhp@mssl.ucl.ac.u

    2010-09-10

    Observations of He-like and H-like Ar (Ar XVII and Ar XVIII) lines at 3.949 A and 3.733 A, respectively, with the RESIK X-ray spectrometer on the CORONAS-F spacecraft, together with temperatures and emission measures from the two channels of GOES, have been analyzed to obtain the abundance of Ar in flare plasmas in the solar corona. The line fluxes per unit emission measure show a temperature dependence like that predicted from theory and lead to spectroscopically determined values for the absolute Ar abundance, A(Ar) = 6.44 {+-} 0.07 (Ar XVII) and 6.49 {+-} 0.16 (Ar XVIII), which are in agreement to within uncertainties. The weighted mean is 6.45 {+-} 0.06, which is between two recent compilations of the solar Ar abundance and suggests that the photospheric and coronal abundances of Ar are very similar.

  10. Aquifer water abundance evaluation using a fuzzy- comprehensive weighting method

    NASA Astrophysics Data System (ADS)

    Wei, Z.

    2016-08-01

    Aquifer water abundance evaluation is a highly relevant issue that has been researched for many years. Despite prior research, problems with the conventional evaluation method remain. This paper establishes an aquifer water abundance evaluation method that combines fuzzy evaluation with a comprehensive weighting method to overcome both the subjectivity and lack of conformity in determining weight by pure data analysis alone. First, this paper introduces the principle of a fuzzy-comprehensive weighting method. Second, the example of well field no. 3 (of a coalfield) is used to illustrate the method's process. The evaluation results show that this method is can more suitably meet the real requirements of aquifer water abundance assessment, leading to more precise and accurate evaluations. Ultimately, this paper provides a new method for aquifer water abundance evaluation.

  11. Stellar oxygen abundances. 3: The oxygen abundance of the very metal poor halo star BD -13 deg 3442

    NASA Technical Reports Server (NTRS)

    King, Jeremy R.

    1994-01-01

    A spectrum of the very metal poor ((Fe/H) approximately -3) halo star BD -13 deg 3442 is presented and used to determine this star's oxygen abundance. Our determination makes BD -13 deg 3442 the most metal poor dwarf (though a somewhat evolved one) with an O abundance determination. The O abundance (determined from the 7774 A O I triped) and (O/Fe) ratio is compared to that of two other metal-poor stars. The (O/Fe) ratio of BD -13 deg 3442 is found to be approximately 0.35 dex larger than that of the other two halo stars. Possible implications of this result are discussed.

  12. Early nucleosynthesis and chemical abundances of stars in globular clusters.

    NASA Astrophysics Data System (ADS)

    Gratton, R. G.

    This cycle of lectures presents a self consistent sketch of current understanding about chemcial composition of globular clusters and its aftermaths. The first two lectures give basic about nucleosynthesis, chemical models, and abundance determinations. Main results for globular clusters are presented in the next two lectures. In the final lecture the author reviews various indices used to derive abundances from photometry and low dispersion spectroscopy.

  13. Abundance analysis of the outer halo globular cluster Palomar 14

    NASA Astrophysics Data System (ADS)

    Çalışkan, Ş.; Christlieb, N.; Grebel, E. K.

    2012-01-01

    We determine the elemental abundances of nine red giant stars belonging to Palomar 14 (Pal 14). Pal 14 is an outer halo globular cluster (GC) at a distance of ~70 kpc. Our abundance analysis is based on high-resolution spectra and one-dimensional stellar model atmospheres. We derived the abundances for the iron peak elements Sc, V, Cr, Mn, Co, Ni, the α-elements O, Mg, Si, Ca, Ti, the light odd element Na, and the neutron-capture elements Y, Zr, Ba, La, Ce, Nd, Eu, Dy, and Cu. Our data do not permit us to investigate light element (i.e., O to Mg) abundance variations. The neutron-capture elements show an r-process signature. We compare our measurements with the abundance ratios of inner and other outer halo GCs, halo field stars, GCs of recognized extragalactic origin, and stars in dwarf spheroidal galaxies (dSphs). The abundance pattern of Pal 14 is almost identical to those of Pal 3 and Pal 4, the next distant members of the outer halo GC population after Pal 14. The abundance pattern of Pal 14 is also similar to those of the inner halo GCs, halo field stars, and GCs of recognized extragalactic origin, but differs from what is customarily found in dSphs field stars. The abundance properties of Pal 14, as well as those of the other outer halo GCs, are thus compatible with an accretion origin from dSphs. Whether or not GC accretion played a role, it seems that the formation conditions of outer halo GCs and GCs in dSphs were similar. Based on observations collected at the European Southern Observatory, Chile (Program IDs 077.B-0769).Tables A.1 and A.2 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/537/A83

  14. Literature survey of isotopic abundance data for 1987-1989

    SciTech Connect

    Holden, N.E. )

    1989-08-09

    I have compiled all of the data on isotopic abundance measurements and their variation in nature for the time period since the last General Assembly. Most of the data deals with the variations in the abundances as given by per mil deviations from some standard. As such, they are not of major interest to the Atomic Weights Commission. However, there were some measurements which are of general interest in this list.

  15. Solar-system abundances and processes of nucleosynthesis

    NASA Technical Reports Server (NTRS)

    Woolum, Dorothy S.

    1988-01-01

    The origin of the elements is studied. The average elemental composition of the solar system is examined and used to infer the primordial solar system abundances of the individual nuclides. Patterns in these nuclide abundances are used as clues to their origin. The possible cosmic significance of the patterns are considered. The astrophysical settings for nucleosynthesis and the chemical evolution of the Galaxy and information based on observed isotopic anomalies in meteorites are taken into account.

  16. THE EFFECTS OF INITIAL ABUNDANCES ON NITROGEN IN PROTOPLANETARY DISKS

    SciTech Connect

    Schwarz, Kamber R.; Bergin, Edwin A.

    2014-12-20

    The dominant form of nitrogen provided to most solar system bodies is currently unknown, though available measurements show that the detected nitrogen in solar system rocks and ices is depleted with respect to solar abundances and the interstellar medium. We use a detailed chemical/physical model of the chemical evolution of a protoplanetary disk to explore the evolution and abundance of nitrogen-bearing molecules. Based on this model, we analyze how initial chemical abundances provided as either gas or ice during the early stages of disk formation influence which species become the dominant nitrogen bearers at later stages. We find that a disk with the majority of its initial nitrogen in either atomic or molecular nitrogen is later dominated by atomic and molecular nitrogen as well as NH{sub 3} and HCN ices, where the dominant species varies with disk radius. When nitrogen is initially in gaseous ammonia, it later becomes trapped in ammonia ice except in the outer disk where atomic nitrogen dominates. For a disk with the initial nitrogen in the form of ammonia ice, the nitrogen remains trapped in the ice as NH{sub 3} at later stages. The model in which most of the initial nitrogen is placed in atomic N best matches the ammonia abundances observed in comets. Furthermore, the initial state of nitrogen influences the abundance of N{sub 2}H{sup +}, which has been detected in protoplanetary disks. Strong N{sub 2}H{sup +} emission is found to be indicative of an N{sub 2} abundance greater than n{sub N{sub 2}}/n{sub H{sub 2}}>10{sup −6} in addition to tracing the CO snow line. Our models also indicate that NO is potentially detectable, with lower N gas abundances leading to higher NO abundances.

  17. Estimating site occupancy and abundance using indirect detection indices

    USGS Publications Warehouse

    Stanley, T.R.; Royle, J. Andrew

    2005-01-01

    Knowledge of factors influencing animal distribution and abundance is essential in many areas of ecological research, management, and policy-making. Because common methods for modeling and estimating abundance (e.g., capture-recapture, distance sampling) are sometimes not practical for large areas or elusive species, indices are sometimes used as surrogate measures of abundance. We present an extension of the Royle and Nichols (2003) generalization of the MacKenzie et al. (2002) site-occupancy model that incorporates length of the sampling interval into the, model for detection probability. As a result, we obtain a modeling framework that shows how useful information can be extracted from a class of index methods we call indirect detection indices (IDIs). Examples of IDIs include scent station, tracking tube, snow track, tracking plate, and hair snare surveys. Our model is maximum likelihood, and it can be used to estimate site occupancy and model factors influencing patterns of occupancy and abundance in space. Under certain circumstances, it can also be used to estimate abundance. We evaluated model properties using Monte Carlo simulations and illustrate the method with tracking tube and scent station data. We believe this model will be a useful tool for determining factors that influence animal distribution and abundance.

  18. Stronger warming effects on microbial abundances in colder regions

    DOE PAGES

    Chen, Ji; Luo, Yiqi; Xia, Jianyang; ...

    2015-12-10

    Soil microbes play critical roles in regulating terrestrial carbon (C) cycle and its feedback to climate change. However, it is still unclear how the soil microbial community and abundance respond to future climate change scenarios. In this meta-analysis, we synthesized the responses of microbial community and abundance to experimental warming from 64 published field studies. Our results showed that warming significantly increased soil microbial abundance by 7.6% on average. When grouped by vegetation or soil types, tundras and histosols had the strongest microbial responses to warming with increased microbial, fungal, and bacterial abundances by 15.0%, 9.5% and 37.0% in tundra,more » and 16.5%, 13.2% and 13.3% in histosols, respectively. We found significant negative relationships of the response ratios of microbial, fungal and bacterial abundances with the mean annual temperature, indicating that warming had stronger effects in colder than warmer regions. Moreover, the response ratios of microbial abundance to warming were positively correlated with those of soil respiration. Our results therefore indicate that the large quantities of C stored in colder regions are likely to be more vulnerable to climate warming than the soil C stored in other warmer regions.« less

  19. DIRECT EVALUATION OF THE HELIUM ABUNDANCES IN OMEGA CENTAURI

    SciTech Connect

    Dupree, A. K.; Avrett, E. H. E-mail: eavrett@cfa.harvard.edu

    2013-08-20

    A direct measure of the helium abundances from the near-infrared transition of He I at 1.08 {mu}m is obtained for two nearly identical red giant stars in the globular cluster Omega Centauri. One star exhibits the He I line; the line is weak or absent in the other star. Detailed non-local thermal equilibrium semi-empirical models including expansion in spherical geometry are developed to match the chromospheric H{alpha}, H{beta}, and Ca II K lines, in order to predict the helium profile and derive a helium abundance. The red giant spectra suggest a helium abundance of Y {<=} 0.22 (LEID 54064) and Y = 0.39-0.44 (LEID 54084) corresponding to a difference in the abundance {Delta}Y {>=} 0.17. Helium is enhanced in the giant star (LEID 54084) that also contains enhanced aluminum and magnesium. This direct evaluation of the helium abundances gives observational support to the theoretical conjecture that multiple populations harbor enhanced helium in addition to light elements that are products of high-temperature hydrogen burning. We demonstrate that the 1.08 {mu}m He I line can yield a helium abundance in cool stars when constraints on the semi-empirical chromospheric model are provided by other spectroscopic features.

  20. Global abundance of planktonic heterotrophic protists in the deep ocean.

    PubMed

    Pernice, Massimo C; Forn, Irene; Gomes, Ana; Lara, Elena; Alonso-Sáez, Laura; Arrieta, Jesus M; del Carmen Garcia, Francisca; Hernando-Morales, Victor; MacKenzie, Roy; Mestre, Mireia; Sintes, Eva; Teira, Eva; Valencia, Joaquin; Varela, Marta M; Vaqué, Dolors; Duarte, Carlos M; Gasol, Josep M; Massana, Ramon

    2015-03-01

    The dark ocean is one of the largest biomes on Earth, with critical roles in organic matter remineralization and global carbon sequestration. Despite its recognized importance, little is known about some key microbial players, such as the community of heterotrophic protists (HP), which are likely the main consumers of prokaryotic biomass. To investigate this microbial component at a global scale, we determined their abundance and biomass in deepwater column samples from the Malaspina 2010 circumnavigation using a combination of epifluorescence microscopy and flow cytometry. HP were ubiquitously found at all depths investigated down to 4000 m. HP abundances decreased with depth, from an average of 72±19 cells ml(-1) in mesopelagic waters down to 11±1 cells ml(-1) in bathypelagic waters, whereas their total biomass decreased from 280±46 to 50±14 pg C ml(-1). The parameters that better explained the variance of HP abundance were depth and prokaryote abundance, and to lesser extent oxygen concentration. The generally good correlation with prokaryotic abundance suggested active grazing of HP on prokaryotes. On a finer scale, the prokaryote:HP abundance ratio varied at a regional scale, and sites with the highest ratios exhibited a larger contribution of fungi molecular signal. Our study is a step forward towards determining the relationship between HP and their environment, unveiling their importance as players in the dark ocean's microbial food web.

  1. TESTING FOR AZIMUTHAL ABUNDANCE GRADIENTS IN M101

    SciTech Connect

    Li, Yanxia; Bresolin, Fabio; Kennicutt, Robert C. Jr.

    2013-03-20

    New optical spectra of 28 H II regions in the M101 disk have been obtained, yielding 10 new detections of the [O III] {lambda}4363 auroral line. The oxygen abundance gradient measured from these data, combined with previous observations, displays a local scatter of 0.15 {+-} 0.03 dex along an arc in the west side of the galaxy, compared with a smaller scatter of 0.08 {+-} 0.01 dex in the rest of the disk. One of the H II regions in our sample (H27) has a significantly lower oxygen abundance than surrounding nebulae at a similar galactocentric distance, while an additional, relatively nearby one (H128) was already known to have a high oxygen abundance for its position in the galaxy. These results represent marginal evidence for the existence of moderate deviations from chemical abundance homogeneity in the interstellar medium of M101. Using a variety of strong-line abundance indicators, we find no evidence for significant large-scale azimuthal variations of the oxygen abundance across the whole disk of the galaxy.

  2. Primordial lithium abundance in catalyzed big bang nucleosynthesis

    NASA Astrophysics Data System (ADS)

    Bird, Chris; Koopmans, Kristen; Pospelov, Maxim

    2008-10-01

    There exists a well-known problem with the Li7+Be7 abundance predicted by standard big bang nucleosynthesis being larger than the value observed in population II stars. The catalysis of big bang nucleosynthesis by metastable, τX≳103sec, charged particles X- is capable of suppressing the primordial Li7+Be7 abundance and making it consistent with the observations. We show that to produce the correct abundance, this mechanism of suppression places a requirement on the initial abundance of X- at temperatures of 4×108K to be on the order of or larger than 0.02 per baryon, which is within the natural range of abundances in models with metastable electroweak-scale particles. The suppression of Li7+Be7 is triggered by the formation of (Be7X-) compound nuclei, with fast depletion of their abundances by catalyzed proton reactions, and in some models by direct capture of X- on Be7. The combination of Li7+Be7 and Li6 constraints favors the window of lifetimes, 1000s≲τX≤2000s.

  3. Stronger warming effects on microbial abundances in colder regions

    SciTech Connect

    Chen, Ji; Luo, Yiqi; Xia, Jianyang; Jiang, Lifen; Zhou, Xuhui; Lu, Meng; Liang, Junyi; Shi, Zheng; Shelton, Shelby; Cao, Junji

    2015-12-10

    Soil microbes play critical roles in regulating terrestrial carbon (C) cycle and its feedback to climate change. However, it is still unclear how the soil microbial community and abundance respond to future climate change scenarios. In this meta-analysis, we synthesized the responses of microbial community and abundance to experimental warming from 64 published field studies. Our results showed that warming significantly increased soil microbial abundance by 7.6% on average. When grouped by vegetation or soil types, tundras and histosols had the strongest microbial responses to warming with increased microbial, fungal, and bacterial abundances by 15.0%, 9.5% and 37.0% in tundra, and 16.5%, 13.2% and 13.3% in histosols, respectively. We found significant negative relationships of the response ratios of microbial, fungal and bacterial abundances with the mean annual temperature, indicating that warming had stronger effects in colder than warmer regions. Moreover, the response ratios of microbial abundance to warming were positively correlated with those of soil respiration. Our results therefore indicate that the large quantities of C stored in colder regions are likely to be more vulnerable to climate warming than the soil C stored in other warmer regions.

  4. Stronger warming effects on microbial abundances in colder regions.

    PubMed

    Chen, Ji; Luo, Yiqi; Xia, Jianyang; Jiang, Lifen; Zhou, Xuhui; Lu, Meng; Liang, Junyi; Shi, Zheng; Shelton, Shelby; Cao, Junji

    2015-12-10

    Soil microbes play critical roles in regulating terrestrial carbon (C) cycle and its feedback to climate change. However, it is still unclear how the soil microbial community and abundance respond to future climate change scenarios. In this meta-analysis, we synthesized the responses of microbial community and abundance to experimental warming from 64 published field studies. Our results showed that warming significantly increased soil microbial abundance by 7.6% on average. When grouped by vegetation or soil types, tundras and histosols had the strongest microbial responses to warming with increased microbial, fungal, and bacterial abundances by 15.0%, 9.5% and 37.0% in tundra, and 16.5%, 13.2% and 13.3% in histosols, respectively. We found significant negative relationships of the response ratios of microbial, fungal and bacterial abundances with the mean annual temperature, indicating that warming had stronger effects in colder than warmer regions. Moreover, the response ratios of microbial abundance to warming were positively correlated with those of soil respiration. Our findings therefore indicate that the large quantities of C stored in colder regions are likely to be more vulnerable to climate warming than the soil C stored in other warmer regions.

  5. The abundance of silicon in the solar atmosphere

    NASA Astrophysics Data System (ADS)

    Shaltout, A. M. K.; Beheary, M. M.; Bakry, A.; Ichimoto, K.

    2013-04-01

    High-resolution solar spectra were used to determine the silicon abundance (εSi) content by comparison with Si line synthesis relying on realistic hydrodynamical simulations of the solar surface convection, as 3D inhomogeneous model of the solar photosphere. Based on a set of 19 Si I and 2 Si II lines, with accurate transition probabilities as well as accurate observational data available, the solar photospheric Si abundance has been determined to be log εSi(3D) = 7.53 ± 0.07. Here we derive the photospheric silicon abundance taking into account non-LTE effects based on 1D solar model, the non-LTE abundance value we find is log εSi (1D) = 7.52 ± 0.08. The photospheric Si abundance agrees well with the results of Asplund and more recently published by Asplund et al. relative to previous 3D-based abundances, the consistency given that the quoted errors here are (±0.07 dex).

  6. Determining the Initial Helium Abundance of the Sun

    NASA Astrophysics Data System (ADS)

    Serenelli, Aldo M.; Basu, Sarbani

    2010-08-01

    We determine the dependence of the initial helium abundance and the present-day helium abundance in the convective envelope of solar models (Y ini and Y surf, respectively) on the parameters that are used to construct the models. We do so by using reference standard solar models (SSMs) to compute the power-law coefficients of the dependence of Y ini and Y surf on the input parameters. We use these dependencies to determine the correlation between Y ini and Y surf and use this correlation to eliminate uncertainties in Y ini from all solar model input parameters except the microscopic diffusion rate. We find an expression for Y ini that depends only on Y surf and the diffusion rate. By adopting the helioseismic determination of solar surface helium abundance, Y surf sun = 0.2485 ± 0.0035, and an uncertainty of 20% for the diffusion rate, we find that the initial solar helium abundance, Y ini sun, is 0.278 ± 0.006 independently of the reference SSMs (and particularly on the adopted solar abundances) used in the derivation of the correlation between Y ini and Y surf. When non-SSMs with extra mixing are used, then we derive Y ini sun = 0.273 ± 0.006. In both cases, the derived Y ini sun value is higher than that directly derived from solar model calibrations when the low-metallicity solar abundances (e.g., by Asplund et al.) are adopted in the models.

  7. Spatial Variations of Dust Abundances Across the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Paradis, Déborah; Reach, William T.; Bernard, Jean-Philippe; Block, Miwa; Engelbracht, Chad W.; Gordon, Karl; Hora, Joseph L.; Indebetouw, Remy; Kawamura, Akiko; Meade, Marilyn; Meixner, Margaret; Sewilo, Marta; Vijh, Uma P.; Volk, Kevin

    2009-07-01

    Using the data obtained with the Spitzer Space Telescope as part of the Surveying the Agents of a Galaxy's Evolution (SAGE) legacy survey, we have studied the variations of the dust composition and abundance across the Large Magellanic Cloud (LMC). Such variations are expected, as the explosive events which have lead to the formation of the many H I shells observed should have affected the dust properties. Using a model and comparing with a reference spectral energy distribution from our Galaxy, we deduce the relative abundance variations of small dust grains across the LMC. We examined the infrared color ratios as well as the relative abundances of very small grains (VSGs) and polycyclic aromatic hydrocarbons (PAHs) relative to the big grain abundance. Results show that each dust component could have different origins or evolution in the interstellar medium (ISM). The VSG abundance traces the star formation activity and could result from shattering of larger grains, whereas the PAH abundance increases around molecular clouds as well as in the stellar bar, where they could have been injected into the ISM during mass loss from old stars.

  8. Chemical abundances of massive stars in Local Group galaxies

    NASA Astrophysics Data System (ADS)

    Venn, Kim A.; Kaufer, Andreas; Tolstoy, Eline; Kudritzki, Rolf-Peter; Przybilla, Norbert; Smartt, Stephen J.; Lennon, Daniel J.

    The relative abundances of elements in galaxies can provide valuable information on the stellar and chemical evolution of a galaxy. While nebulae can provide abundances for a variety of light elements, stars are the only way to directly determine the abundances of iron-group and s-process and r-process elements in a galaxy. The new 8m and 10m class telescopes and high-efficiency spectrographs now make high-quality spectral observations of bright supergiants possible in dwarf galaxies in the Local Group. We have been concentrating on elemental abundances in the metal-poor dwarf irregular galaxies, NGC 6822, WLM, Sextants A, and GR 8. Comparing abundance ratios to those predicted from their star formation histories, determined from color-magnitude diagrams, and comparing those ratios between these galaxies can give us new insights into the evolution of these dwarf irregular galaxies. Iron-group abundances also allow us to examine the metallicities of the stars in these galaxies directly, which affects their inferred mass loss rates and predicted stellar evolution properties.

  9. SULFUR ABUNDANCES IN THE ORION ASSOCIATION B STARS

    SciTech Connect

    Daflon, Simone; Cunha, Katia; De la Reza, Ramiro; Holtzman, Jon; Chiappini, Cristina

    2009-12-15

    Sulfur abundances are derived for a sample of 10 B main-sequence star members of the Orion association. The analysis is based on LTE plane-parallel model atmospheres and non-LTE line formation theory by means of a self-consistent spectrum synthesis analysis of lines from two ionization states of sulfur, S II and S III. The observations are high-resolution spectra obtained with the ARCES spectrograph at the Apache Point Observatory. The abundance distribution obtained for the Orion targets is homogeneous within the expected errors in the analysis: A(S) = 7.15 {+-} 0.05. This average abundance result is in agreement with the recommended solar value (both from modeling of the photospheres in one-dimensional and three-dimensional, and meteorites) and indicates that little, if any, chemical evolution of sulfur has taken place in the last {approx}4.5 billion years. The sulfur abundances of the young stars in Orion are found to agree well with results for the Orion Nebulae, and place strong constraints on the amount of sulfur depletion onto grains as being very modest or nonexistent. The sulfur abundances for Orion are consistent with other measurements at a similar galactocentric radius: combined with previous results for other OB-type stars produce a relatively shallow sulfur abundance gradient with a slope of -0.037 {+-} 0.012 dex kpc{sup -1}.

  10. SPATIAL VARIATIONS OF DUST ABUNDANCES ACROSS THE LARGE MAGELLANIC CLOUD

    SciTech Connect

    Paradis, Deborah; Reach, William T.; Bernard, Jean-Philippe; Block, Miwa; Engelbracht, Chad W.; Gordon, Karl; Hora, Joseph L.; Indebetouw, Remy; Kawamura, Akiko; Meade, Marilyn; Meixner, Margaret; Sewilo, Marta; Vijh, Uma P.; Volk, Kevin

    2009-07-15

    Using the data obtained with the Spitzer Space Telescope as part of the Surveying the Agents of a Galaxy's Evolution (SAGE) legacy survey, we have studied the variations of the dust composition and abundance across the Large Magellanic Cloud (LMC). Such variations are expected, as the explosive events which have lead to the formation of the many H I shells observed should have affected the dust properties. Using a model and comparing with a reference spectral energy distribution from our Galaxy, we deduce the relative abundance variations of small dust grains across the LMC. We examined the infrared color ratios as well as the relative abundances of very small grains (VSGs) and polycyclic aromatic hydrocarbons (PAHs) relative to the big grain abundance. Results show that each dust component could have different origins or evolution in the interstellar medium (ISM). The VSG abundance traces the star formation activity and could result from shattering of larger grains, whereas the PAH abundance increases around molecular clouds as well as in the stellar bar, where they could have been injected into the ISM during mass loss from old stars.

  11. Relative resource abundance explains butterfly biodiversity in island communities.

    PubMed

    Yamamoto, Naoaki; Yokoyama, Jun; Kawata, Masakado

    2007-06-19

    Ecologists have long been intrigued by the factors that control the pattern of biodiversity, i.e., the distribution and abundance of species. Previous studies have demonstrated that coexisting species partition their resources and/or that the compositional similarity between communities is determined by environmental factors, lending support to the niche-assembly model. However, no attempt has been made to test whether the relative amount of resources that reflects relative niche space controls relative species abundance in communities. Here, we demonstrate that the relative abundance of butterfly species in island communities is significantly related to the relative biomasses of their host plants but not to the geographic distance between communities. In the studied communities, the biomass of particular host plant species positively affected the abundance of the butterfly species that used them, and consequently, influenced the relative abundance of the butterfly communities. This indicated that the niche space of butterflies (i.e., the amount of resources) strongly influences butterfly biodiversity patterns. We present this field evidence of the niche-apportionment model that propose that the relative amount of niche space explains the pattern of the relative abundance of the species in communities.

  12. CHROMOSPHERIC MODELS AND THE OXYGEN ABUNDANCE IN GIANT STARS

    SciTech Connect

    Dupree, A. K.; Avrett, E. H.; Kurucz, R. L.

    2016-04-10

    Realistic stellar atmospheric models of two typical metal-poor giant stars in Omega Centauri, which include a chromosphere (CHR), influence the formation of optical lines of O i: the forbidden lines (λ6300, λ6363) and the infrared triplet (λλ7771−7775). One-dimensional semi-empirical non-local thermodynamic equilibrium (LTE) models are constructed based on observed Balmer lines. A full non-LTE formulation is applied for evaluating the line strengths of O i, including photoionization by the Lyman continuum and photoexcitation by Lyα and Lyβ. Chromospheric models (CHR) yield forbidden oxygen transitions that are stronger than those in radiative/convective equilibrium (RCE) models. The triplet oxygen lines from high levels also appear stronger than those produced in an RCE model. The inferred oxygen abundance from realistic CHR models for these two stars is decreased by factors of ∼3 as compared to values derived from RCE models. A lower oxygen abundance suggests that intermediate-mass AGB stars contribute to the observed abundance pattern in globular clusters. A change in the oxygen abundance of metal-poor field giants could affect models of deep mixing episodes on the red giant branch. Changes in the oxygen abundance can impact other abundance determinations that are critical to astrophysics, including chemical tagging techniques and galactic chemical evolution.

  13. Antarctic mixotrophic protist abundances by microscopy and molecular methods.

    PubMed

    Gast, Rebecca J; McKie-Krisberg, Zaid M; Fay, Scott A; Rose, Julie M; Sanders, Robert W

    2014-08-01

    Protists are traditionally described as either phototrophic or heterotrophic, but studies have indicated that mixotrophic species, organisms that combine both strategies, can have significant impacts on prey populations in marine microbial food webs. While estimates of active mixotroph abundances in environmental samples are determined microscopically by fluorescent particle ingestion, species identification is difficult. We developed SYBR-based qPCR strategies for three Antarctic algal species that we identified as mixotrophic. This method and traditional ingestion experiments were applied to determine the total mixotroph abundance in Antarctic water samples, to ascertain the abundance of known mixotrophic species, and to identify environmental variables that impact the distribution and abundance of these species. Despite differences in sampling locations and years, mixotroph distribution was strongly influenced by season. Environmental variables that best explained variation in the individual mixotroph species abundances included temperature, oxygen, date, fluorescence, conductivity, and latitude. Phosphate was identified as an additional explanatory variable when nutrients were included in the analysis. Utilizing culture-based grazing rates and qPCR abundances, the estimated summed impact on bacterial populations by the three mixotrophs was usually < 2% of the overall mixotrophic grazing, but in one sample, Pyramimonas was estimated to contribute up to 80% of mixotrophic grazing.

  14. THE SOLAR FLARE SULFUR ABUNDANCE FROM RESIK OBSERVATIONS

    SciTech Connect

    Sylwester, J.; Sylwester, B.; Phillips, K. J. H.; Kuznetsov, V. D. E-mail: bs@cbk.pan.wroc.pl E-mail: kvd@izmiran.ru

    2012-06-01

    The RESIK instrument on CORONAS-F spacecraft observed several sulfur X-ray lines in three of its four channels covering the wavelength range 3.8-6.1 A during solar flares. The fluxes are analyzed to give the sulfur abundance. Data are chosen for when the instrument parameters were optimized. The measured fluxes of the S XV 1s{sup 2}-1s4p (w4) line at 4.089 A gives A(S) = 7.16 {+-} 0.17 (abundances on a logarithmic scale with A(H) = 12) which we consider to be the most reliable. Estimates from other lines range from 7.13 to 7.24. The preferred S abundance estimate is very close to recent photospheric abundance estimates and to quiet-Sun solar wind and meteoritic abundances. This implies no fractionation of sulfur by processes tending to enhance the coronal abundance from the photospheric that depend on the first ionization potential (FIP), or that sulfur, though its FIP has an intermediate value of 10.36 eV, acts like a 'high-FIP' element.

  15. Integrated electrical connector

    DOEpatents

    Benett, William J.; Ackler, Harold D.

    2005-05-24

    An electrical connector is formed from a sheet of electrically conductive material that lies in between the two layers of nonconducting material that comprise the casing of an electrical chip. The connector is electrically connected to an electrical element embedded within the chip. An opening in the sheet is concentrically aligned with a pair of larger holes respectively bored through the nonconducting layers. The opening is also smaller than the diameter of an electrically conductive contact pin. However, the sheet is composed flexible material so that the opening adapts to the diameter of the pin when the pin is inserted therethrough. The periphery of the opening applies force to the sides of the pin when the pin is inserted, and thus holds the pin within the opening and in contact with the sheet, by friction. The pin can be withdrawn from the connector by applying sufficient axial force.

  16. Electrical system architecture

    DOEpatents

    Algrain, Marcelo C.; Johnson, Kris W.; Akasam, Sivaprasad; Hoff, Brian D.

    2008-07-15

    An electrical system for a vehicle includes a first power source generating a first voltage level, the first power source being in electrical communication with a first bus. A second power source generates a second voltage level greater than the first voltage level, the second power source being in electrical communication with a second bus. A starter generator may be configured to provide power to at least one of the first bus and the second bus, and at least one additional power source may be configured to provide power to at least one of the first bus and the second bus. The electrical system also includes at least one power consumer in electrical communication with the first bus and at least one power consumer in electrical communication with the second bus.

  17. Thermoacoustic magnetohydrodynamic electrical generator

    DOEpatents

    Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1986-01-01

    A thermoacoustic magnetohydrodynamic electrical generator includes an intrinsically irreversible thermoacoustic heat engine coupled to a magnetohydrodynamic electrical generator. The heat engine includes an electrically conductive liquid metal as the working fluid and includes two heat exchange and thermoacoustic structure assemblies which drive the liquid in a push-pull arrangement to cause the liquid metal to oscillate at a resonant acoustic frequency on the order of 1,000 Hz. The engine is positioned in the field of a magnet and is oriented such that the liquid metal oscillates in a direction orthogonal to the field of the magnet, whereby an alternating electrical potential is generated in the liquid metal. Low-loss, low-inductance electrical conductors electrically connected to opposite sides of the liquid metal conduct an output signal to a transformer adapted to convert the low-voltage, high-current output signal to a more usable higher voltage, lower current signal.

  18. Thermoacoustic magnetohydrodynamic electrical generator

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1984-11-16

    A thermoacoustic magnetohydrodynamic electrical generator includes an intrinsically irreversible thermoacoustic heat engine coupled to a magnetohydrodynamic electrical generator. The heat engine includes an electrically conductive liquid metal as the working fluid and includes two heat exchange and thermoacoustic structure assemblies which drive the liquid in a push-pull arrangement to cause the liquid metal to oscillate at a resonant acoustic frequency on the order of 1000 Hz. The engine is positioned in the field of a magnet and is oriented such that the liquid metal oscillates in a direction orthogonal to the field of the magnet, whereby an alternating electrical potential is generated in the liquid metal. Low-loss, low-inductance electrical conductors electrically connected to opposite sides of the liquid metal conduct an output signal to a transformer adapted to convert the low-voltage, high-current output signal to a more usable higher voltage, lower current signal.

  19. Electric power monthly

    SciTech Connect

    1995-08-01

    The Energy Information Administration (EIA) prepares the Electric Power Monthly (EPM) for a wide audience including Congress, Federal and State agencies, the electric utility industry, and the general public. This publication provides monthly statistics for net generation, fossil fuel consumption and stocks, quantity and quality of fossil fuels, cost of fossil fuels, electricity sales, revenue, and average revenue per kilowatthour of electricity sold. Data on net generation, fuel consumption, fuel stocks, quantity and cost of fossil fuels are also displayed for the North American Electric Reliability Council (NERC) regions. The EIA publishes statistics in the EPM on net generation by energy source, consumption, stocks, quantity, quality, and cost of fossil fuels; and capability of new generating units by company and plant. The purpose of this publication is to provide energy decisionmakers with accurate and timely information that may be used in forming various perspectives on electric issues that lie ahead.

  20. The earth's electrical environment

    SciTech Connect

    Not Available

    1986-01-01

    This latest addition to the Studies in Geophysics series explores in scientific detail the phenomenon of lighting, cloud and thunderstorm electricity, and global and regional electrical processes. Consisting of 16 papers by outstanding experts in a number of fields, this volume compiles and reviews many recent advances in such research areas as meteorology, chemistry, electrical engineering, and physics and projects how new knowledge could be applied to benefit mankind.

  1. Electrical control of superparamagnetism

    NASA Astrophysics Data System (ADS)

    Yamada, Kihiro T.; Koyama, Tomohiro; Kakizakai, Haruka; Miwa, Kazumoto; Ando, Fuyuki; Ishibashi, Mio; Kim, Kab-Jin; Moriyama, Takahiro; Ono, Shimpei; Chiba, Daichi; Ono, Teruo

    2017-01-01

    The electric field control of superparamagnetism is realized using a Cu/Ni system, in which the deposited Ni shows superparamagnetic behavior above the blocking temperature. An electric double-layer capacitor (EDLC) with the Cu/Ni electrode and a nonmagnetic counter electrode is fabricated to examine the electric field effect on magnetism in the magnetic electrode. By changing the voltage applied to the EDLC, the blocking temperature of the system is clearly modulated.

  2. Essays on electricity theft

    NASA Astrophysics Data System (ADS)

    Steadman, Keva Ullanda

    Electricity theft is a relatively unknown crime with high economic costs. In this dissertation, I try to identify the factors that motivate persons to steal electricity. First, I use a panel dataset of 97 countries spanning the five year period 2003--2007 to estimate a model that describes the effect of the unemployment rate, GDP per capita, male population and urbanization on theft, robbery and homicide rates. The results are consistent with previous empirical work on crime and economic opportunity. The second and main contribution of this paper is to estimate the same model using distribution loss as a proxy for electricity theft. The results show that the unemployment rate, a key explanatory economic factor for crime, cannot explain variation in electricity theft, although there is some evidence, albeit weak, supporting correlation in rich countries. Therefore, policies that target the reduction of property crime through a reduction in unemployment will have no effect on electricity theft. The third contribution relates to the role that political institutions play in the incentives to steal electricity. After control for socioeconomic factors, I find that there is no relationship between political governance indicators and electricity theft. In the second and third chapters, I compare the United States, a high income, low electricity theft country with Jamaica, a middle income, high electricity theft country. The effect of unemployment on electricity theft mirrors the results found in the first chapter. In the United States, electricity theft is affected by changes in economic conditions but in Jamaica, it is not. These results suggest that the state of institutions plays a role in how social norms are determined. Poor countries will be more likely than rich countries to have weak institutions with social norms that encourage electricity theft.

  3. Expendable Electric Landrover (EEL)

    DTIC Science & Technology

    2004-07-01

    DAHLGREN DIVISION NAVAL SURFACE WARFARE CENTER Panama City, Florida 32407-7001 NSWC PC/MP-04/07 EXPENDABLE ELECTRIC LANDROVER (EEL) MITCH GAVRILASH...COVERED JULY 2004 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS EXPENDABLE ELECTRIC LANDROVER (EEL) 6. AUTHOR(S) MITCH GAVRILASH 7. PERFORMING ORGANIZATION NAME...generations of Expendable Electric Landrover (EEL) robots were developed during fiscal year 2003 at the Naval Surface Warfare Center, Panama City (NSWC-PC

  4. Electric Drive Study

    DTIC Science & Technology

    1987-03-01

    Track-Laying Combat Vehicles , and (3) Parametric Study of Electric Drive Component Technologies. The technology survey results are given in a separate...and projections of future electric drive system improvements relative to combat vehicle applications. Unclassified SECURITY CLASSIFICATION OF THIS...273 5.7.2.3.1 DC Homopolar Drum Machine, Design and Performance 5-278 APPENDIX A 19.5 TON AND 40.0 TON VEHICLE SPECIFICATION APPENDIX B ELECTRIC

  5. Inferring invasive species abundance using removal data from management actions.

    PubMed

    Davis, Amy J; Hooten, Mevin B; Miller, Ryan S; Farnsworth, Matthew L; Lewis, Jesse; Moxcey, Michael; Pepin, Kim M

    2016-10-01

    Evaluation of the progress of management programs for invasive species is crucial for demonstrating impacts to stakeholders and strategic planning of resource allocation. Estimates of abundance before and after management activities can serve as a useful metric of population management programs. However, many methods of estimating population size are too labor intensive and costly to implement, posing restrictive levels of burden on operational programs. Removal models are a reliable method for estimating abundance before and after management using data from the removal activities exclusively, thus requiring no work in addition to management. We developed a Bayesian hierarchical model to estimate abundance from removal data accounting for varying levels of effort, and used simulations to assess the conditions under which reliable population estimates are obtained. We applied this model to estimate site-specific abundance of an invasive species, feral swine (Sus scrofa), using removal data from aerial gunning in 59 site/time-frame combinations (480-19,600 acres) throughout Oklahoma and Texas, USA. Simulations showed that abundance estimates were generally accurate when effective removal rates (removal rate accounting for total effort) were above 0.40. However, when abundances were small (<50) the effective removal rate needed to accurately estimates abundances was considerably higher (0.70). Based on our post-validation method, 78% of our site/time frame estimates were accurate. To use this modeling framework it is important to have multiple removals (more than three) within a time frame during which demographic changes are minimized (i.e., a closed population; ≤3 months for feral swine). Our results show that the probability of accurately estimating abundance from this model improves with increased sampling effort (8+ flight hours across the 3-month window is best) and increased removal rate. Based on the inverse relationship between inaccurate abundances and

  6. Modeling avian abundance from replicated counts using binomial mixture models

    USGS Publications Warehouse

    Kery, Marc; Royle, J. Andrew; Schmid, Hans

    2005-01-01

    Abundance estimation in ecology is usually accomplished by capture–recapture, removal, or distance sampling methods. These may be hard to implement at large spatial scales. In contrast, binomial mixture models enable abundance estimation without individual identification, based simply on temporally and spatially replicated counts. Here, we evaluate mixture models using data from the national breeding bird monitoring program in Switzerland, where some 250 1-km2 quadrats are surveyed using the territory mapping method three times during each breeding season. We chose eight species with contrasting distribution (wide–narrow), abundance (high–low), and detectability (easy–difficult). Abundance was modeled as a random effect with a Poisson or negative binomial distribution, with mean affected by forest cover, elevation, and route length. Detectability was a logit-linear function of survey date, survey date-by-elevation, and sampling effort (time per transect unit). Resulting covariate effects and parameter estimates were consistent with expectations. Detectability per territory (for three surveys) ranged from 0.66 to 0.94 (mean 0.84) for easy species, and from 0.16 to 0.83 (mean 0.53) for difficult species, depended on survey effort for two easy and all four difficult species, and changed seasonally for three easy and three difficult species. Abundance was positively related to route length in three high-abundance and one low-abundance (one easy and three difficult) species, and increased with forest cover in five forest species, decreased for two nonforest species, and was unaffected for a generalist species. Abundance estimates under the most parsimonious mixture models were between 1.1 and 8.9 (median 1.8) times greater than estimates based on territory mapping; hence, three surveys were insufficient to detect all territories for each species. We conclude that binomial mixture models are an important new approach for estimating abundance corrected for

  7. Inferring invasive species abundance using removal data from management actions

    USGS Publications Warehouse

    Davis, Amy J.; Hooten, Mevin B.; Miller, Ryan S.; Farnsworth, Matthew L.; Lewis, Jesse S.; Moxcey, Michael; Pepin, Kim M.

    2016-01-01

    Evaluation of the progress of management programs for invasive species is crucial for demonstrating impacts to stakeholders and strategic planning of resource allocation. Estimates of abundance before and after management activities can serve as a useful metric of population management programs. However, many methods of estimating population size are too labor intensive and costly to implement, posing restrictive levels of burden on operational programs. Removal models are a reliable method for estimating abundance before and after management using data from the removal activities exclusively, thus requiring no work in addition to management. We developed a Bayesian hierarchical model to estimate abundance from removal data accounting for varying levels of effort, and used simulations to assess the conditions under which reliable population estimates are obtained. We applied this model to estimate site-specific abundance of an invasive species, feral swine (Sus scrofa), using removal data from aerial gunning in 59 site/time-frame combinations (480–19,600 acres) throughout Oklahoma and Texas, USA. Simulations showed that abundance estimates were generally accurate when effective removal rates (removal rate accounting for total effort) were above 0.40. However, when abundances were small (<50) the effective removal rate needed to accurately estimates abundances was considerably higher (0.70). Based on our post-validation method, 78% of our site/time frame estimates were accurate. To use this modeling framework it is important to have multiple removals (more than three) within a time frame during which demographic changes are minimized (i.e., a closed population; ≤3 months for feral swine). Our results show that the probability of accurately estimating abundance from this model improves with increased sampling effort (8+ flight hours across the 3-month window is best) and increased removal rate. Based on the inverse relationship between inaccurate abundances and

  8. Chemical abundances of solar-type dwarfs in open clusters

    NASA Astrophysics Data System (ADS)

    Schuler, Simon C.

    Open clusters have proven continuously to be invaluable tools to the studies of stellar physics and Galactic evolution. Until recently, however, the chemical abundances of the populous and astrophysically important late-F, G, and K open cluster dwarfs have gone largely unanalyzed. In this thesis I report on the study of the chemical abundances derived from high-resolution, moderate-to-high signal-to-noise echelle spectra obtained with the 10-m Keck I, 9.2-m Hobby- Eberly, 8.2-m VLT, 4.0-m KPNO, 2.7-m Harlan J. Smith, and the 2.1-m Otto Struve telescopes of cool dwarfs in the Pleiades, Hyades, and M34 open clusters. The main result of the study is the identification of excitation-related abundance trends found among cool open cluster dwarfs ( T eff <= 5500 K), as well as an overionization of Fe- abundances derived from singly ionized lines are greater than those derived from neutral lines- among the cool Hyades dwarfs; the trends are such that abundances derived from high-excitation (h >= 4.0 eV) spectral lines and using atmospheric models assuming local thermodynamic equilibrium (LTE) increase with decreasing T eff . Particular attention is given to the high-excitation (h = 9.15 eV) near-IR ll7774 O I triplet, a line used often in the derivation of stellar O abundances and known to be susceptible to non-LTE (NLTE) effects. The O I triplet-based abundances show a dramatic increase with decreasing T eff in all three clusters, behavior that is in stark contrast to expectations from canonical NLTE calculations. Other elements with lines of various excitation potentials are also analyzed and are found to exhibit abundance trends that are qualitatively similar to those of the O I triplet. Possible explanations for the observed cool open cluster dwarf abundance anomalies are investigated, and photospheric surface temperature inhomogeneities possibly due to spots, faculae, and/or plages are found to be a plausible culprit. Indeed, multi-component LTE model atmospheres are

  9. Electric vehicle's electricity consumption on a road with different slope

    NASA Astrophysics Data System (ADS)

    Yang, S. C.; Li, M.; Lin, Y.; Tang, T. Q.

    2014-05-01

    In this paper, we propose an extended car-following model and an electricity consumption model to study the effects of the road's slope on the electric vehicle's electricity consumption. The numerical results show that each electric vehicle's electricity consumption increases with the uphill's tilt angle and decreases with the downhill's tilt angle. In addition, each electric vehicle's electricity consumption increases with the uphill's (downhill's) length under a certain tilt angle.

  10. Electric power annual 1992

    SciTech Connect

    Not Available

    1994-01-06

    The Electric Power Annual presents a summary of electric utility statistics at national, regional and State levels. The objective of the publication is to provide industry decisionmakers, government policymakers, analysts and the general public with historical data that may be used in understanding US electricity markets. The Electric Power Annual is prepared by the Survey Management Division; Office of Coal, Nuclear, Electric and Alternate Fuels; Energy Information Administration (EIA); US Department of Energy. ``The US Electric Power Industry at a Glance`` section presents a profile of the electric power industry ownership and performance, and a review of key statistics for the year. Subsequent sections present data on generating capability, including proposed capability additions; net generation; fossil-fuel statistics; retail sales; revenue; financial statistics; environmental statistics; electric power transactions; demand-side management; and nonutility power producers. In addition, the appendices provide supplemental data on major disturbances and unusual occurrences in US electricity power systems. Each section contains related text and tables and refers the reader to the appropriate publication that contains more detailed data on the subject matter. Monetary values in this publication are expressed in nominal terms.

  11. Electric vehicle propulsion alternatives

    NASA Technical Reports Server (NTRS)

    Secunde, R. R.; Schuh, R. M.; Beach, R. F.

    1983-01-01

    Propulsion technology development for electric vehicles is summarized. Analytical studies, technology evaluation, and the development of technology for motors, controllers, transmissions, and complete propulsion systems are included.

  12. Electrical Circuit Tester

    DOEpatents

    Love, Frank

    2006-04-18

    An electrical circuit testing device is provided, comprising a case, a digital voltage level testing circuit with a display means, a switch to initiate measurement using the device, a non-shorting switching means for selecting pre-determined electrical wiring configurations to be tested in an outlet, a terminal block, a five-pole electrical plug mounted on the case surface and a set of adapters that can be used for various multiple-pronged electrical outlet configurations for voltages from 100 600 VAC from 50 100 Hz.

  13. Electrical Power Requirements.

    DTIC Science & Technology

    POWER SUPPLIES, TEST METHODS), ARMY EQUIPMENT, BATTERY COMPONENTS, ELECTRIC BATTERIES, VEHICLES, GENERATORS, FUEL CELLS, SEEBECK EFFECT , TEST EQUIPMENT, ELECTROMAGNETIC COMPATIBILITY, DATA PROCESSING

  14. Electrically conductive cellulose composite

    DOEpatents

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  15. Perforation patterned electrical interconnects

    SciTech Connect

    Frey, Jonathan

    2014-01-28

    This disclosure describes systems and methods for increasing the usable surface area of electrical contacts within a device, such as a thin film solid state device, through the implementation of electrically conductive interconnects. Embodiments described herein include the use of a plurality of electrically conductive interconnects that penetrate through a top contact layer, through one or more multiple layers, and into a bottom contact layer. The plurality of conductive interconnects may form horizontal and vertical cross-sectional patterns. The use of lasers to form the plurality of electrically conductive interconnects from reflowed layer material further aids in the manufacturing process of a device.

  16. A search for stars of very low metal abundance. VI. Detailed abundances of 313 metal-poor stars

    SciTech Connect

    Roederer, Ian U.; Preston, George W.; Thompson, Ian B.; Shectman, Stephen A.; Burley, Gregory S.; Kelson, Daniel D.; Sneden, Christopher

    2014-06-01

    We present radial velocities, equivalent widths, model atmosphere parameters, and abundances or upper limits for 53 species of 48 elements derived from high resolution optical spectroscopy of 313 metal-poor stars. A majority of these stars were selected from the metal-poor candidates of the HK Survey of Beers, Preston, and Shectman. We derive detailed abundances for 61% of these stars for the first time. Spectra were obtained during a 10 yr observing campaign using the Magellan Inamori Kyocera Echelle spectrograph on the Magellan Telescopes at Las Campanas Observatory, the Robert G. Tull Coudé Spectrograph on the Harlan J. Smith Telescope at McDonald Observatory, and the High Resolution Spectrograph on the Hobby-Eberly Telescope at McDonald Observatory. We perform a standard LTE abundance analysis using MARCS model atmospheres, and we apply line-by-line statistical corrections to minimize systematic abundance differences arising when different sets of lines are available for analysis. We identify several abundance correlations with effective temperature. A comparison with previous abundance analyses reveals significant differences in stellar parameters, which we investigate in detail. Our metallicities are, on average, lower by ≈0.25 dex for red giants and ≈0.04 dex for subgiants. Our sample contains 19 stars with [Fe/H] ≤–3.5, 84 stars with [Fe/H] ≤–3.0, and 210 stars with [Fe/H] ≤–2.5. Detailed abundances are presented here or elsewhere for 91% of the 209 stars with [Fe/H] ≤–2.5 as estimated from medium resolution spectroscopy by Beers, Preston, and Shectman. We will discuss the interpretation of these abundances in subsequent papers.

  17. Multiresidue analysis of 36 pesticides in soil using a modified quick, easy, cheap, effective, rugged, and safe method by liquid chromatography with tandem quadruple linear ion trap mass spectrometry.

    PubMed

    Feng, Xue; He, Zeying; Wang, Lu; Peng, Yi; Luo, Ming; Liu, Xiaowei

    2015-09-01

    A new method for simultaneous determination of 36 pesticides, including 15 organophosphorus, six carbamate, and some other pesticides in soil was developed by liquid chromatography with tandem quadruple linear ion trap mass spectrometry. The extraction and clean-up steps were optimized based on the quick, easy, cheap, effective, rugged, and safe method. The data were acquired in multiple reaction monitoring mode combined with enhanced product ion to increase confidence of the analytical results. Validation experiments were performed in soil samples. The average recoveries of pesticides at four spiking levels (1, 5, 50, and 100 μg/kg) ranged from 63 to 126% with relative standard deviation below 20%. The limits of detection of pesticides were 0.04-0.8 μg/kg, and the limits of quantification were 0.1-2.6 μg/kg. The correlation coefficients (r(2) ) were higher than 0.990 in the linearity range of 0.5-200 μg/L for most of the pesticides. The method allowed for the analysis of the target pesticides in the lower μg/kg concentration range. The optimized method was then applied to the test of real soil samples obtained from several areas in China, confirming the feasibility of the method.

  18. Alternative sorbents for the dispersive solid-phase extraction step in quick, easy, cheap, effective, rugged and safe method for extraction of pesticides from rice paddy soils with determination by liquid chromatography tandem mass spectrometry.

    PubMed

    Arias, Jean Lucas de Oliveira; Rombaldi, Caroline; Caldas, Sergiane Souza; Primel, Ednei Gilberto

    2014-09-19

    The clean-up step is essential to reduce interferences, improve quantification and help to maintain the integrity of the chromatographic system when working with complex matrices. In this study, alternative materials were evaluated as sorbents in the dispersive solid-phase extraction (D-SPE) for the determination and extraction of seventeen pesticides from rice paddy soil samples by the quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chitin, chitosan, diatomaceous earth and PSA were compared in terms of extraction efficiency and matrix effect. The best results were achieved when chitosan was used. Quantification limits ranged from 0.1 to 100μgkg(-1). Calibration curves showed correlation coefficient values higher than 0.98. Results of accuracy and precision in the spiked soil samples between 60% and 120%, with a relative standard deviation lower than 20%, were reached for 15 out of 17 pesticides. The matrix effect was evaluated and only one compound was influenced by the matrix components, showing medium effect. Results showed that alternative materials are more effective and less expensive than traditional sorbents which have been usually employed, i.e., they may be used in the D-SPE step during the extraction of pesticides from rice paddy soils.

  19. A simplified Quick, Easy, Cheap, Effective, Rugged and Safe approach for the determination of trihalomethanes and benzene, toluene, ethylbenzene and xylenes in soil matrices by fast gas chromatography with mass spectrometry detection.

    PubMed

    García Pinto, Carmelo; Herrero Martín, Sara; Pérez Pavón, José Luis; Moreno Cordero, Bernardo

    2011-03-09

    A method based on simplified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction followed by large-injection volume-fast gas chromatography and mass spectrometry detection has been developed for the determination of trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane and bromoform) and BTEX (benzene, toluene, ethylbenzene and xylenes) in soil samples. The simplified version of QuEChERS used meets the requirements of the "green chemistry" and provides reliable results with high sample throughput, low solvent consumption, little labour and the use of materials commonly employed in laboratories. The GC device used is equipped with a programmable temperature vaporizer (PTV), with a liner packed with Tenax-TA(®). Using the solvent-vent mode, the PTV allows the injection of large volumes of sample, affording an improvement in the sensitivity of the method. The chromatographic conditions used here allowed the separation of the compounds in less than 5.50 min. Good linearity was obtained for all the target compounds, with highly satisfactory repeatability and reproducibility values. The limits of detection were in the 0.2 to 15 μg kg(-1) range. The method was validated by the analysis of two certified reference materials.

  20. A cheap, simple high throughput method for screening native Helicobacter pylori urease inhibitors using a recombinant Escherichia coli, its validation and demonstration of Pistacia atlantica methanolic extract effectivity and specificity.

    PubMed

    Amar, Natalie; Peretz, Avi; Gerchman, Yoram

    2017-02-01

    Helicobacter pylori is the most frequent and persistent bacterial infection worldwide, and a risk factor for active gastritis, peptic ulcers, mucosa-associated lymphoid tissue lymphoma, and gastric cancer. Although combined antibiotics treatment is effective cases of antibiotic resistance are reported at an alarming rate. The H. pylori urease enzyme is essential for the bacteria establishment in the gastric mucosa, resulting urease inhibitors being sought after as effective and specific anti- H. pylori treatment. To-date, screening assays are based mostly on the analog plant urease enzyme but difference in properties of the plant and bacterial enzymes hamper these efforts. We have developed a screening assay based on recombinant Escherichia coli expressing native H. pylori urease, and validated this assay using thiourea and a methanolic extract of Pistacia atlantica. The assay demonstrated the thiourea and the extract to be potent urease inhibitors, with the extract having strong bacteriostatic activity against clinical isolates of H. pylori, including such with antibiotic resistance. The extract was also found to be neutral toward common probiotic bacteria, supporting its specificity and compatibility with digestive system desired microflora and suggesting it could be a good source for anti-H. pylori compounds. The assay has proven to be cheap, simple and native alternative to the plant enzyme based assay and could allow for high throughput screening for new urease inhibitors and could expedite screening and development of novel, better H. pylori remedies helping us to combat this infection.

  1. A quick, easy, cheap, effective, rugged, and safe method for the simultaneous detection of four triazolone herbicides in cereals combined with ultrahigh performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Tao, Yan; Xu, Jun; Liu, Xingang; Cheng, Youpu; Liu, Na; Chen, Zenglong; Dong, Fengshou; Zheng, Yonguan

    2014-09-01

    This paper describes a novel, rapid, and sensitive analytical method for monitoring four triazolone herbicides in cereals (wheat, rice, corn, and soybean), using a quick, easy, cheap, effective, rugged, and safe sample extraction procedure followed by ultrahigh performance liquid chromatography coupled with tandem mass spectrometry. The four triazolone herbicides (amicarbazone, carfentrazone-ethyl, sulfentrazone, and thiencarbazone-methyl) were extracted using acidified acetonitrile (containing 1% v/v formic acid) and subsequently purified with octadecylsilane (C18 ) prior to sample analysis. Ultrahigh performance liquid chromatography coupled with tandem mass spectrometry was operated in positive and negative ionization switching mode. Amicarbazone and carfentrazone-ethyl were detected in the positive mode (ESI+), while sulfentrazone and thiencarbazone-methyl were detected in the negative mode (ESI-). All compounds were successfully separated in less than 3.0 min. Further optimization achieved desired recoveries ranging from 74.5 to 102.1% for all analytes with relative standard deviation values ≤17.2% in all tested matrices at three levels (10, 100, and 500 μg/kg). The limits of detection for all compounds were ≤2.3 μg/kg, and the limits of quantitation did not exceed 7.1 μg/kg. The developed method showed excellent linearity (R(2) ≥ 0.994) and was proven to be highly efficient and reliable for the routine monitoring of triazolone herbicides in cereals.

  2. Evaluation of two modified quick, easy, cheap, effective, rugged and safe (QuEChERS) sample preparation methods for the analysis of baclofen and gabapentin in feeds by liquid chromatography tandem mass spectrometry.

    PubMed

    Hou, Xiao-Lin; Wu, Yin-Liang; Chen, Ruo-Xia; Zhu, Yong; Lv, Yan; Xu, Xiu-Qin

    2014-01-01

    This paper presents a new analytical method for the simultaneous determination of baclofen and gabapentin in feeds based on two modified quick, easy, cheap, effective, rugged and safe (QuEChERS) sample preparation methods and liquid chromatography tandem mass spectrometry (LC-MS/MS). For the two modified QuEChERS methods, samples were first extracted with acidified acetonitrile (5.0% acetic acid, v/v) without using acetonitrile salting-out extraction. Then, the first modified QuEChERS method was established according to the original QuEChERS cleanup procedure. For the second modified QuEChERS method, the extract was evaporated to dryness and reconstituted in acetonitrile. Subsequently, the analytes in the reconstituted solution were retained by primary secondary amine (PSA) and released from PSA with 1.0% formic acid in methanol. Finally, the eluate was evaporated and dissolved in 0.1% formic acid solution/methanol (v/v, 80:20). All of the samples were analyzed by LC-MS/MS on a Waters Acquity BEH C18 column with 0.1% formic acid in water/methanol as the mobile phase with gradient elution. The matrix effect, recovery, and repeatability, within laboratory reproducibility, and the LODs and LOQs of the two modified QuEChERS sample preparation methods were investigated and compared. Comparative results showed that the second method was obviously superior to the first method.

  3. Determination of 136 pharmaceuticals and hormones in sewage sludge using quick, easy, cheap, effective, rugged and safe extraction followed by analysis with liquid chromatography-time-of-flight-mass spectrometry.

    PubMed

    Peysson, William; Vulliet, Emmanuelle

    2013-05-17

    The aim of this study was to develop an analytical method for the analysis of a wide range of hormonal steroids and pharmaceutical compounds in sewage sludge. Thus, 136 substances were selected, including 119 pharmaceuticals and 17 hormonal steroids. An innovative sample preparation procedure based on the quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed. The analysis was then performed using liquid chromatography coupled with time-of-flight mass spectrometry. This analytical procedure was validated by evaluating the specificity, quadratic curve fitting, recovery, reproducibility and limits of detection and quantification. The method allows the analysis of the majority of the target compounds with limits of detection ranging from 1 ng/g to 2500 ng/g, depending on the nature of the substance. The protocol was then successfully applied to various types of sludge (limed, digested, dried, liquid and composted) collected in several sewage works in France. Among the target compounds, 34 were quantified at levels up to 6000 ng/g. Among the most commonly detected pharmaceuticals were the antiemetic domperidone (mean concentration 769 ng/g) and the antiepileptic lamotrigine (mean concentration 31 ng/g) whose presence had, to our knowledge, never been shown in sludge.

  4. Simultaneous determination of spirotetramat and its four metabolites in fruits and vegetables using a modified quick, easy, cheap, effective, rugged, and safe method and liquid chromatography/tandem mass spectrometry.

    PubMed

    Zhu, Yulong; Liu, Xingang; Xu, Jun; Dong, Fengshou; Liang, Xuyang; Li, Minmin; Duan, Lifang; Zheng, Yongquan

    2013-07-19

    A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for the simultaneous determination of spirotetramat and its four metabolites in fruits (apple, peach) and vegetables (cabbage, tomato, potato, cucumber), based on the use of liquid extraction/partition and dispersive solid phase extraction (dispersive-SPE) followed by ultrahigh-performance chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS), was established. Acidified acetonitrile (containing 1% (v/v) acetic acid) as the extraction solvent and simultaneous liquid-liquid partitioning formed by adding anhydrous magnesium sulfate (MgSO4) and anhydrous sodium acetate (NaOAc). The extract was then cleaned up by dispersive-SPE using graphitized carbon black (GCB) as selective sorbent. Further optimization of sample preparation and determination achieved recoveries of between 82 and 110% for all analytes with RSD values lower than 14% in apple, peach, cabbage, tomato, potato and cucumber at three levels (10, 100 and 1000μg/kg). The method showed excellent linearity (R(2)≥0.9895) for all studied analytes. The determination of the target compounds was achieved in less than 6.0min using an electrospray ionization source in positive mode (ESI+). The method is demonstrated to be convenient and reliable for the routine monitoring of spirotetramat and its metabolites in fruits and vegetables.

  5. Innovative mixture of salts in the quick, easy, cheap, effective, rugged, and safe method for the extraction of residual macrolides in milk followed by analysis with liquid chromatography and tandem mass spectrometry.

    PubMed

    da Costa, Rafaela Pinto; Spisso, Bernardete Ferraz; Pereira, Mararlene Ulberg; Monteiro, Mychelle Alves; Ferreira, Rosana Gomes; da Nóbrega, Armi Wanderley

    2015-11-01

    A simple extraction technique has been developed for seven macrolide antibiotics in milk. The procedure involves a modified quick, easy, cheap, effective, rugged, and safe method based on acetonitrile extraction, followed by the addition of a mixture of salts (sodium sulfate, sodium chloride, and potassium carbonate) not yet reported in literature. The method was validated for tylosin and was selective, free of matrix effect, and linear in the range of 0.78-18.75 ng/mL in the final extract, corresponding to 0.125-3 times the maximum residue limit. The limit of detection, limit of quantification, decision limit, and detection capability were, respectively, 0.84, 2.79, 58.4, and 71.7 μg/kg. The overall average recovery at 25, 50, and 75 μg/kg ranged from 89-97%. Repeatability and intermediate precision expressed by relative standard deviations were below 10.5 and 12%, respectively. The extension of the validation for spiramycin, throleandomycin, oleandomycin, roxithromycin, erythromycin, and clarithromycin is under consideration since the procedure proved to be able to efficiently extract all studied macrolides, with recoveries from 74-104% at 50 μg/kg for tylosin, erythromycin, spiramycin, and oleandomycin and 20 μg/kg for throleandomycin, roxithromycin, and clarithromycin.

  6. Simultaneous determination of flupyradifurone and its two metabolites in fruits, vegetables, and grains by a modified quick, easy, cheap, effective, rugged, and safe method using ultra high performance liquid chromatography with tandem mass spectrometry.

    PubMed

    Li, Yao; Liu, Xingang; Wu, Xiaohu; Dong, Fengshou; Xu, Jun; Zheng, Yongquan

    2016-03-01

    An effective analytical method for the simultaneous determination of a novel insecticide flupyradifurone and its two metabolites was developed using ultra high performance liquid chromatography with tandem mass spectrometry coupled with a quick, easy, cheap, effective, rugged, and safe procedure. The three target compounds were extracted with acetonitrile and cleaned up with octadecylsilane, and were separated successfully between 1.9 and 3.1 min using an HSS T3 chromatographic column connected to an electrospray ionization source. All the matrix-matched samples at three fortified levels (0.01, 0.05, and 0.5 mg/kg) provided satisfactory recoveries in the range of 70.3-116.5% with relative standard deviations below 18.6%. The limits of quantitation were 10 μg/kg for flupyradifurone and difluoroethylamino-furanone and 100 μg/kg for 6-chloronicotinic acid. The limit of quantification of flupyradifurone was far below the maximum residue limit in the USA. The method is of great significance for establishing maximum residue limits in China.

  7. Microbial abundance in surface ice on the Greenland Ice Sheet

    PubMed Central

    Stibal, Marek; Gözdereliler, Erkin; Cameron, Karen A.; Box, Jason E.; Stevens, Ian T.; Gokul, Jarishma K.; Schostag, Morten; Zarsky, Jakub D.; Edwards, Arwyn; Irvine-Fynn, Tristram D. L.; Jacobsen, Carsten S.

    2015-01-01

    Measuring microbial abundance in glacier ice and identifying its controls is essential for a better understanding and quantification of biogeochemical processes in glacial ecosystems. However, cell enumeration of glacier ice samples is challenging due to typically low cell numbers and the presence of interfering mineral particles. We quantified for the first time the abundance of microbial cells in surface ice from geographically distinct sites on the Greenland Ice Sheet (GrIS), using three enumeration methods: epifluorescence microscopy (EFM), flow cytometry (FCM), and quantitative polymerase chain reaction (qPCR). In addition, we reviewed published data on microbial abundance in glacier ice and tested the three methods on artificial ice samples of realistic cell (102–107 cells ml−1) and mineral particle (0.1–100 mg ml−1) concentrations, simulating a range of glacial ice types, from clean subsurface ice to surface ice to sediment-laden basal ice. We then used multivariate statistical analysis to identify factors responsible for the variation in microbial abundance on the ice sheet. EFM gave the most accurate and reproducible results of the tested methodologies, and was therefore selected as the most suitable technique for cell enumeration of ice containing dust. Cell numbers in surface ice samples, determined by EFM, ranged from ~ 2 × 103 to ~ 2 × 106 cells ml−1 while dust concentrations ranged from 0.01 to 2 mg ml−1. The lowest abundances were found in ice sampled from the accumulation area of the ice sheet and in samples affected by fresh snow; these samples may be considered as a reference point of the cell abundance of precipitants that are deposited on the ice sheet surface. Dust content was the most significant variable to explain the variation in the abundance data, which suggests a direct association between deposited dust particles and cells and/or by their provision of limited nutrients to microbial communities on the GrIS. PMID:25852678

  8. Abundance of Hepatic Transporters in Caucasians: A Meta-Analysis

    PubMed Central

    Burt, Howard J.; Riedmaier, Arian Emami; Harwood, Matthew D.; Crewe, H. Kim; Gill, Katherine L.

    2016-01-01

    This study aimed to derive quantitative abundance values for key hepatic transporters suitable for in vitro–in vivo extrapolation within a physiologically based pharmacokinetic modeling framework. A meta-analysis was performed whereby data on abundance measurements, sample preparation methods, and donor demography were collated from the literature. To define values for a healthy Caucasian population, a subdatabase was created whereby exclusion criteria were applied to remove samples from non-Caucasian individuals, those with underlying disease, or those with subcellular fractions other than crude membrane. Where a clinically relevant active genotype was known, only samples from individuals with an extensive transporter phenotype were included. Authors were contacted directly when additional information was required. After removing duplicated samples, the weighted mean, geometric mean, standard deviation, coefficient of variation, and between-study homogeneity of transporter abundances were determined. From the complete database containing 24 transporters, suitable abundance data were available for 11 hepatic transporters from nine studies after exclusion criteria were applied. Organic anion transporting polypeptides OATP1B1 and OATP1B3 showed the highest population abundance in healthy adult Caucasians. For several transporters, the variability in abundance was reduced significantly once the exclusion criteria were applied. The highest variability was observed for OATP1B3 > OATP1B1 > multidrug resistance protein 2 > multidrug resistance gene 1. No relationship was found between transporter expression and donor age. To our knowledge, this study provides the first in-depth analysis of current quantitative abundance data for a wide range of hepatic transporters, with the aim of using these data for in vitro–in vivo extrapolation, and highlights the significance of investigating the background of tissue(s) used in quantitative transporter proteomic studies. Similar

  9. Songbird abundance and parasitism differ between urban and rural shrublands.

    PubMed

    Burhans, Dirk E; Thompson, Frank R

    2006-02-01

    Many studies have examined differences in avian community composition between urban and rural habitats, but few, if any, have looked at nesting success of urban shrubland birds in a replicated fashion while controlling for habitat. We tested factors affecting nest survival, parasitism by the Brown-headed Cowbird (Molothrus ater), and species abundance in shrubland habitat in rural and urban landscapes. We found no support for our hypothesis that nest survival was lower in urban landscapes, but strong support for the hypothesis that survival increased with nest height. We found strong support for our hypothesis that cowbird parasitism was greater in urban than rural landscapes; parasitism in urban sites was at least twice that of rural sites. We found strong support for an urban landscape effect on abundance for several species; Northern Cardinal (Cardinalis cardinalis) and Brown-headed Cowbirds were more abundant in urban landscapes, whereas Field Sparrow (Spizella pusilla) and Blue-winged Warbler (Vermivora pinus) were more abundant in rural sites. There was support for lower abundances of Blue-gray Gnatcatcher (Polioptila caerulea) and Indigo Bunting (Passerina cyanea) with increased housing density. For six other species, edge and trail density or vegetation parameters best explained abundance. Lower abundances and greater parasitism in habitat patches in urban landscapes are evidence that, for some species, these urban landscapes do not fulfill the same role as comparable habitats in rural landscapes. Regional bird conservation planning and local habitat management in urban landscapes may need to consider these effects in efforts to sustain bird populations at regional and local scales.

  10. Urban warming drives insect pest abundance on street trees.

    PubMed

    Meineke, Emily K; Dunn, Robert R; Sexton, Joseph O; Frank, Steven D

    2013-01-01

    Cities profoundly alter biological communities, favoring some species over others, though the mechanisms that govern these changes are largely unknown. Herbivorous arthropod pests are often more abundant in urban than in rural areas, and urban outbreaks have been attributed to reduced control by predators and parasitoids and to increased susceptibility of stressed urban plants. These hypotheses, however, leave many outbreaks unexplained and fail to predict variation in pest abundance within cities. Here we show that the abundance of a common insect pest is positively related to temperature even when controlling for other habitat characteristics. The scale insect Parthenolecanium quercifex was 13 times more abundant on willow oak trees in the hottest parts of Raleigh, NC, in the southeastern United States, than in cooler areas, though parasitism rates were similar. We further separated the effects of heat from those of natural enemies and plant quality in a greenhouse reciprocal transplant experiment. P. quercifex collected from hot urban trees became more abundant in hot greenhouses than in cool greenhouses, whereas the abundance of P. quercifex collected from cooler urban trees remained low in hot and cool greenhouses. Parthenolecanium quercifex living in urban hot spots succeed with warming, and they do so because some demes have either acclimatized or adapted to high temperatures. Our results provide the first evidence that heat can be a key driver of insect pest outbreaks on urban trees. Since urban warming is similar in magnitude to global warming predicted in the next 50 years, pest abundance on city trees may foreshadow widespread outbreaks as natural forests also grow warmer.

  11. Global Distribution of Microbial Abundance and Biomass in Subseafloor Sediment

    NASA Astrophysics Data System (ADS)

    Kallmeyer, J.; Pockalny, R. A.; Adhikari, R. R.; Smith, D. C.; D'Hondt, S. L.

    2012-12-01

    Previously published cell counts were mostly from ocean margins and the eastern equatorial Pacific. Cell counts from these environments are generally similar from site to site and decrease logarithmically with sediment depth, although there can be sharp peaks of high cell densities in zones of anaerobic methane-oxidation. Recent counts from the South Pacific Gyre and the North Pacific Gyre are several orders of magnitude lower and show a more rapid decrease with depth than all previously published datasets. With these new data available, total microbial cell abundance in subseafloor sediment varies between sites by ca. five orders of magnitude. The differences between cell counts from ocean margins and upwelling areas and cell counts from oceanic gyres raise three questions. First, how does the abundance of microbes in subseafloor sediment vary throughout the world ocean? Second, what property or properties are likely to control that variation? Third, how does this variation affect estimates of total subseafloor sedimentary biomass and Earth's total biomass? To address these questions, we compiled our cell counts from the South Pacific Gyre, the North Pacific Gyre and the eastern equatorial Pacific Ocean with previously published counts and parameterized the cell distribution at each site and determined two parameters, (i) cell concentration at 1 mbsf and (ii) rate of decrease in cell counts with depth. Both parameters are strongly correlated with mean sedimentation rate and distance to shore. Based on these correlations, we estimate global subseafloor sedimentary microbial abundance to be 2.9*1029 cells (corresponding to 4.1 Pg C and ~0.6% of Earth's total living biomass). This estimate of subseafloor sedimentary microbial abundance is roughly equal to previous estimates of total microbial abundance in seawater and total microbial abundance in soil. It is much lower than previous estimates of subseafloor sedimentary microbial abundance. In consequence, we estimate

  12. Change in avian abundance predicted from regional forest inventory data

    USGS Publications Warehouse

    Twedt, Daniel J.; Tirpak, John M.; Jones-Farrand, D. Todd; Thompson, Frank R.; Uihlein, William B.; Fitzgerald, Jane A.

    2010-01-01

    An inability to predict population response to future habitat projections is a shortcoming in bird conservation planning. We sought to predict avian response to projections of future forest conditions that were developed from nationwide forest surveys within the Forest Inventory and Analysis (FIA) program. To accomplish this, we evaluated the historical relationship between silvicolous bird populations and FIA-derived forest conditions within 25 ecoregions that comprise the southeastern United States. We aggregated forest area by forest ownership, forest type, and tree size-class categories in county-based ecoregions for 5 time periods spanning 1963-2008. We assessed the relationship of forest data with contemporaneous indices of abundance for 24 silvicolous bird species that were obtained from Breeding Bird Surveys. Relationships between bird abundance and forest inventory data for 18 species were deemed sufficient as predictive models. We used these empirically derived relationships between regional forest conditions and bird populations to predict relative changes in abundance of these species within ecoregions that are anticipated to coincide with projected changes in forest variables through 2040. Predicted abundances of these 18 species are expected to remain relatively stable in over a quarter (27%) of the ecoregions. However, change in forest area and redistribution of forest types will likely result in changed abundance of some species within many ecosystems. For example, abundances of 11 species, including pine warbler (Dendroica pinus), brown-headed nuthatch (Sitta pusilla), and chuckwills- widow (Caprimulgus carolinensis), are projected to increase within more ecoregions than ecoregions where they will decrease. For 6 other species, such as blue-winged warbler (Vermivora pinus), Carolina wren (Thryothorus ludovicianus), and indigo bunting (Passerina cyanea), we projected abundances will decrease within more ecoregions than ecoregions where they will

  13. Spatial patterns in the abundance of the coastal horned lizard

    USGS Publications Warehouse

    Fisher, Robert N.; Suarez, Andrew V.; Case, Ted J.

    2002-01-01

    Coastal horned lizards (   Phrynosoma coronatum) have undergone severe declines in southern California and are a candidate species for state and federal listing under the Endangered Species Act. Quantitative data on their habitat use, abundance, and distribution are lacking, however. We investigated the determinants of abundance for coastal horned lizards at multiple spatial scales throughout southern California. Specifically, we estimated lizard distribution and abundance by establishing 256 pitfall trap arrays clustered within 21 sites across four counties. These arrays were sampled bimonthly for 2–3 years. At each array we measured 26 “local” site descriptors and averaged these values with other “regional” measures to determine site characteristics. Our analyses were successful at identifying factors within and among sites correlated with the presence and abundance of coastal horned lizards. These factors included the absence of the invasive Argentine ant (  Linepithema humile) (and presence of native ant species eaten by the lizards), the presence of chaparral community plants, and the presence of sandy substrates. At a regional scale the relative abundance of Argentine ants was correlated with the relative amount of developed edge around a site. There was no evidence for spatial autocorrelation, even at the scale of the arrays within sites, suggesting that the determinants of the presence or absence and abundance of horned lizard can vary over relatively small spatial scales ( hundreds of meters). Our results suggest that a gap-type approach may miss some of the fine-scale determinants of species abundance in fragmented habitats.

  14. Abundant proteorhodopsin genes in the North Atlantic Ocean.

    PubMed

    Campbell, Barbara J; Waidner, Lisa A; Cottrell, Matthew T; Kirchman, David L

    2008-01-01

    Proteorhodopsin (PR) is a light-driven proton pump that has been found in a variety of marine bacteria, including Pelagibacter ubique, a member of the ubiquitous SAR11 clade. The goals of this study were to explore the diversity of PR genes and to estimate their abundance in the North Atlantic Ocean using quantitative polymerase chain reaction (QPCR). We found that PR genes in the western portion of the Sargasso Sea could be grouped into 27 clusters, but five clades had the most sequences. Sets of specific QPCR primers were designed to examine the abundance of PR genes in the following four of the five clades: SAR11 (P. ubique and other SAR11 Alphaproteobacteria), BACRED17H8 (Alphaproteobacteria), HOT2C01 (Alphaproteobacteria) and an uncultured subgroup of the Flavobacteria. Two groups (SAR11 and HOT2C01) dominated PR gene abundance in oligotrophic waters, but were significantly less abundant in nutrient- and chlorophyll-rich waters. The other two groups (BACRED17H8 and Flavobacteria subgroup NASB) were less abundant in all waters. Together, these four PR gene types were found in 50% of all bacteria in the Sargasso Sea. We found a significant negative correlation between total PR gene abundance and nutrients and chlorophyll but no significant correlation with light intensity for three of the four PR types in the depth profiles north of the Sargasso Sea. Our data suggest that PR is common in the North Atlantic Ocean, especially in SAR11 bacteria and another marine alphaproteobacterial group (HOT2C01), and that these PR-bearing bacteria are most abundant in oligotrophic waters.

  15. On the influence of the environment on galactic chemical abundances

    NASA Astrophysics Data System (ADS)

    Pilyugin, L. S.; Grebel, E. K.; Zinchenko, I. A.; Nefedyev, Y. A.; Mattsson, L.

    2017-02-01

    We examine the influence of the environment on the chemical abundances of late-type galaxies with masses of 109.1-1011 M⊙ using data from the Sloan Digital Sky Survey. We find that the environmental influence on galactic chemical abundances is strongest for galaxies with masses of 109.1-109.6 M⊙. The galaxies in the densest environments may exceed the average oxygen abundances by about ∼0.05 dex (the median value of the overabundances for 101 galaxies in the densest environments) and show higher abundances in nitrogen by about ∼0.1. The abundance excess decreases with increasing galaxy mass and with decreasing environmental density. Since only a small fraction of late-type galaxies is located in high-density environments, these galaxies do not have a significant influence on the general X/H-M relation. The metallicity-mass relations for isolated galaxies and for galaxies with neighbours are very similar. The mean shift of non-isolated galaxies around the metallicity-mass relation traced by the isolated galaxies is less than ∼0.01 dex for oxygen and less than ∼0.02 dex for nitrogen. The scatter in the galactic chemical abundances is large for any number of neighbour galaxies (at any environmental density), i.e. galaxies with both enhanced and reduced abundances can be found at any environmental density. This suggests that environmental effects do not play a key role in evolution of late-type galaxies, as was also concluded in some of the previous studies.

  16. New aerial survey and hierarchical model to estimate manatee abundance

    USGS Publications Warehouse

    Langimm, Cahterine A.; Dorazio, Robert M.; Stith, Bradley M.; Doyle, Terry J.

    2011-01-01

    Monitoring the response of endangered and protected species to hydrological restoration is a major component of the adaptive management framework of the Comprehensive Everglades Restoration Plan. The endangered Florida manatee (Trichechus manatus latirostris) lives at the marine-freshwater interface in southwest Florida and is likely to be affected by hydrologic restoration. To provide managers with prerestoration information on distribution and abundance for postrestoration comparison, we developed and implemented a new aerial survey design and hierarchical statistical model to estimate and map abundance of manatees as a function of patch-specific habitat characteristics, indicative of manatee requirements for offshore forage (seagrass), inland fresh drinking water, and warm-water winter refuge. We estimated the number of groups of manatees from dual-observer counts and estimated the number of individuals within groups by removal sampling. Our model is unique in that we jointly analyzed group and individual counts using assumptions that allow probabilities of group detection to depend on group size. Ours is the first analysis of manatee aerial surveys to model spatial and temporal abundance of manatees in association with habitat type while accounting for imperfect detection. We conducted the study in the Ten Thousand Islands area of southwestern Florida, USA, which was expected to be affected by the Picayune Strand Restoration Project to restore hydrology altered for a failed real-estate development. We conducted 11 surveys in 2006, spanning the cold, dry season and warm, wet season. To examine short-term and seasonal changes in distribution we flew paired surveys 1–2 days apart within a given month during the year. Manatees were sparsely distributed across the landscape in small groups. Probability of detection of a group increased with group size; the magnitude of the relationship between group size and detection probability varied among surveys. Probability

  17. Electricity market module: Electricity capacity planning submodule

    SciTech Connect

    1996-06-01

    The purpose of this report is to describe modifications to the Electricity Capacity Planning Submodule (ECP) for the Annual Energy Outlook 1996. It describes revisions to enhance the representation of planned maintenance, incorporate technological improvements in operating efficiencies, revise the algorithm for determining international firm power imports, and include risk premiums for new plant construction.

  18. Molecular and functional asymmetry at a vertebrate electrical synapse

    PubMed Central

    Rash, John R.; Curti, Sebastian; Vanderpool, Kimberly G. V.; Kamasawa, Naomi; Nannapaneni, Srikant; Palacios-Prado, Nicolas; Flores, Carmen E.; Yasumura, Thomas; O’Brien, John; Lynn, Bruce D.; Bukauskas, Feliksas; Nagy, James I.; Pereda, Alberto E.

    2013-01-01

    SUMMARY Electrical synapses are abundant in the vertebrate brain, but their functional and molecular complexity are still poorly understood. We report here that electrical synapses between auditory afferents and goldfish Mauthner cells are constructed by apposition of hemichannels formed by two homologs of mammalian connexin36 (Cx36), and that while Cx35 is restricted to presynaptic hemiplaques, Cx34.7 is restricted to postsynaptic hemiplaques, forming heterotypic junctions. This molecular asymmetry is associated with rectification of electrical transmission that may act to promote cooperativity between auditory afferents. Our data suggest that in similarity to pre- and postsynaptic sites at chemical synapses, one side in electrical synapses should not necessarily be considered the mirror image of the other. While asymmetry based on the presence of two Cx36 homologs is restricted to teleost fish, it might also be based on differences in posttranslational modifications of individual connexins or in the complement of gap junction-associated proteins. PMID:24012008

  19. Applications of abundance data and requirements for cosmochemical modeling

    SciTech Connect

    Busemann, H.; Binns, W. R.; Chiappini, C.; Gloeckler, G.; Hoppe, P.; Kirilova, Donka; Leske, R. A.; Manuel, O. K.; Wiens, R. C.

    2001-01-01

    Understanding the evolution of the universe from Big Bang to its present state requires an understanding of the evolution of the abundances of the elements and isotopes in galaxies, stars, the interstellar medium, the Sun and the heliosphere, planets and meteorites. Processes that change the state of the universe include Big Bang nucleosynthesis, star formation and stellar nucleosynthesis, galactic chemical evolution, propagation of cosmic rays, spallation, ionization and particle transport of interstellar material, formation of the solar system, solar wind emission and its fractionation (FIP/FIT effect), mixing processes in stellar interiors, condensation of material and subsequent geochemical fractionation. Here, we attempt to compile some major issues in cosmochemistry that can be addressed with a better knowledge of the respective element or isotope abundances. Present and future missions such as Genesis, Stardust, Interstellar Pathfinder, and Interstellar Probe, improvements of remote sensing instrumentation and experiments on extraterrestrial material such as meteorites, presolar grains, and lunar or returned planetary or cometary samples will result in an improved database of elemental and isotopic abundances. This includes the primordial abundances of D, 3He, 4He, and 7Li, abundances of the heavier elements in stars and galaxies, the composition of the interstellar medium, solar wind and comets as well as the (highly) volatile elements in the solar system such as helium, nitrogen, oxygen or xenon.

  20. Generalized estimators of avian abundance from count survey data

    USGS Publications Warehouse

    Royle, J. Andrew

    2004-01-01

    I consider modeling avian abundance from spatially referenced bird count data collected according to common protocols such as capture?recapture, multiple observer, removal sampling and simple point counts. Small sample sizes and large numbers of parameters have motivated many analyses that disregard the spatial indexing of the data, and thus do not provide an adequate treatment of spatial structure. I describe a general framework for modeling spatially replicated data that regards local abundance as a random process, motivated by the view that the set of spatially referenced local populations (at the sample locations) constitute a metapopulation. Under this view, attention can be focused on developing a model for the variation in local abundance independent of the sampling protocol being considered. The metapopulation model structure, when combined with the data generating model, define a simple hierarchical model that can be analyzed using conventional methods. The proposed modeling framework is completely general in the sense that broad classes of metapopulation models may be considered, site level covariates on detection and abundance may be considered, and estimates of abundance and related quantities may be obtained for sample locations, groups of locations, unsampled locations. Two brief examples are given, the first involving simple point counts, and the second based on temporary removal counts. Extension of these models to open systems is briefly discussed.

  1. Low abundance of Archaeorhizomycetes among fungi in soil metatranscriptomes

    PubMed Central

    Choma, Michal; Bárta, Jiří; Šantrůčková, Hana; Urich, Tim

    2016-01-01

    The Archaeorhizomycetes are recently discovered fungi with poorly resolved ecology. Even their abundance in soil fungal communities is currently disputed. Here we applied a PCR-independent, RNA-based metatranscriptomic approach to determine their abundance among fungi in eleven different soils across Europe. Using small subunit (SSU) ribosomal RNA transcripts as marker, we detected Archaeorhizomycetes in 17 out of 28 soil metatranscriptomes. They had average relative SSU rRNA abundance of 2.0% with a maximum of 9.4% among fungal SSU rRNAs. Network analysis revealed that they co-occur with arbuscular mycorrhizal Glomerales, which is in line with their previously suggested association with plant roots. Moreover, Archaeorhizomycetes ranked among the potential keystone taxa. This metatranscriptomic survey exemplifies the usage of non-targeted molecular approaches for the study of soil fungi. It provides PCR- and DNA-independent evidence for the low abundance of Archaeorhizomycetes in soil fungal communities, although they might be non-negligible players despite their low abundance. PMID:28009005

  2. Study on the Abundance Discrepancy Problem in the Magellanic Clouds

    NASA Astrophysics Data System (ADS)

    Toribio San Cipriano, L.; Esteban, C.; Domínguez-Guzmán, G.; García-Rojas, J.

    2017-03-01

    We present chemical abundances of carbon (C) and oxygen (O) in the Large and Small Magellanic Clouds from deep and high-quality optical spectra of H II regions. The data have been taken using the Ultraviolet-Visual Echelle Spectrograph at the 8.2-m Very Large Telescope with the goal of detecting the faint C II and O II recombination lines. For all the objects of the sample, we determine C^{2+}abundances from recombination lines and O^{2+} abundances from recombination lines and collisionally excited lines. In addition, we calculate the abundance discrepancy factors (ADFs) for O^{2+} and C^{2+}, as well as the O/H, C/H and C/O ratios. We study the behaviour of the ADF comparing the values obtained in the Magellanic Clouds with those obtained for other H_{II} regions in different galaxies. We also compare the nebular and stellar abundances in two regions of the sample. Finally, we discuss the chemical evolution of the MCs through the O/H, C/H and C/O radial gradients and the changes of the C/O ratio as a function of O/H.

  3. Fundamental Constraints on the Abundances of Chemotaxis Proteins

    NASA Astrophysics Data System (ADS)

    Bitbol, Anne-Florence; Wingreen, Ned S.

    2015-03-01

    Flagellated bacteria, such as Escherichia coli, perform directed motion in gradients of concentration of attractants and repellents in a process called chemotaxis. The E. coli chemotaxis signaling pathway is a model for signal transduction, but it has unique features. We demonstrate that the need for fast signaling necessitates high abundances of the proteins involved in this pathway. We show that further constraints on the abundances of chemotaxis proteins arise from the requirements of self-assembly, both of flagellar motors and of chemoreceptor arrays. All these constraints are specific to chemotaxis, and published data confirm that chemotaxis proteins tend to be more highly expressed than their homologs in other pathways. Employing a chemotaxis pathway model, we show that the gain of the pathway at the level of the response regulator CheY increases with overall chemotaxis protein abundances. This may explain why, at least in one E. coli strain, the abundance of all chemotaxis proteins is higher in media with lower nutrient content. We also demonstrate that the E. coli chemotaxis pathway is particularly robust to abundance variations of the motor protein FliM.

  4. Stellar chemical abundances: in pursuit of the highest achievable precision

    SciTech Connect

    Bedell, Megan; Bean, Jacob L.; Meléndez, Jorge; Leite, Paulo; Asplund, Martin

    2014-11-01

    The achievable level of precision on photospheric abundances of stars is a major limiting factor on investigations of exoplanet host star characteristics, the chemical histories of star clusters, and the evolution of the Milky Way and other galaxies. While model-induced errors can be minimized through the differential analysis of spectrally similar stars, the maximum achievable precision of this technique has been debated. As a test, we derive differential abundances of 19 elements from high-quality asteroid-reflected solar spectra taken using a variety of instruments and conditions. We treat the solar spectra as being from unknown stars and use the resulting differential abundances, which are expected to be zero, as a diagnostic of the error in our measurements. Our results indicate that the relative resolution of the target and reference spectra is a major consideration, with use of different instruments to obtain the two spectra leading to errors up to 0.04 dex. Use of the same instrument at different epochs for the two spectra has a much smaller effect (∼0.007 dex). The asteroid used to obtain the solar standard also has a negligible effect (∼0.006 dex). Assuming that systematic errors from the stellar model atmospheres have been minimized, as in the case of solar twins, we confirm that differential chemical abundances can be obtained at sub-0.01 dex precision with due care in the observations, data reduction, and abundance analysis.

  5. Influence of edge on predator prey distribution and abundance

    NASA Astrophysics Data System (ADS)

    Ferguson, Steven H.

    2004-03-01

    I investigated the effect of spatial configuration on distribution and abundance of invertebrate trophic groups by counting soil arthropods under boxes (21 × 9.5 cm) arranged in six different patterns that varied in the amount of edge (137-305 cm). I predicted fewer individuals from the consumer trophic group (Collembola) in box groups with greater amount of edge. This prediction was based on the assumption that predators (mites, ants, spiders, centipedes) select edge during foraging and thereby reduce abundance of the less mobile consumer group under box patterns with greater edge. Consumer abundance (Collembola) was not correlated with amount of edge. Among the predator groups, mite, ant and centipede abundance related to the amount of edge of box groups. However, in contrast to predictions, abundance of these predators was negatively correlated with amount of edge in box patterns. All Collembola predators, with the exception of ants, were less clumped in distribution than Collembola. The results are inconsistent with the view that predators used box edges to predate the less mobile consumer trophic group. Alternative explanations for the spatial patterns other than predator-prey relations include (1) a negative relationship between edge and moisture, (2) a positive relationship between edge and detritus decomposition (i.e. mycelium as food for the consumer group), and (3) a negative relationship between edge and the interstices between adjacent boxes. Landscape patterns likely affect microclimate, food, and predator-prey relations and, therefore, future experimental designs need to control these factors individually to distinguish among alternative hypotheses.

  6. Factors affecting Culicoides species composition and abundance in avian nests.

    PubMed

    Martínez-de la Puente, J; Merino, S; Tomás, G; Moreno, J; Morales, J; Lobato, E; Talavera, S; Sarto I Monteys, V

    2009-08-01

    Mechanisms affecting patterns of vector distribution among host individuals may influence the population and evolutionary dynamics of vectors, hosts and the parasites transmitted. We studied the role of different factors affecting the species composition and abundance of Culicoides found in nests of the blue tit (Cyanistes caeruleus). We identified 1531 females and 2 males of 7 different Culicoides species in nests, with C. simulator being the most abundant species, followed by C. kibunensis, C. festivipennis, C. segnis, C. truncorum, C. pictipennis and C. circumscriptus. We conducted a medicationxfumigation experiment randomly assigning bird's nests to different treatments, thereby generating groups of medicated and control pairs breeding in fumigated and control nests. Medicated pairs were injected with the anti-malarial drug Primaquine diluted in saline solution while control pairs were injected with saline solution. The fumigation treatment was carried out using insecticide solution or water for fumigated and control nests respectively. Brood size was the main factor associated with the abundance of biting midges probably because more nestlings may produce higher quantities of vector attractants. In addition, birds medicated against haemoparasites breeding in non-fumigated nests supported a higher abundance of C. festivipennis than the rest of the groups. Also, we found that the fumigation treatment reduced the abundance of engorged Culicoides in both medicated and control nests, thus indicating a reduction of feeding success produced by the insecticide. These results represent the first evidence for the role of different factors in affecting the Culicoides infracommunity in wild avian nests.

  7. The Mean Life Squared Relationship for Abundances of Extinct Radioactivities

    NASA Technical Reports Server (NTRS)

    Lodders, K.; Cameron, A. G. W.

    2004-01-01

    We discovered that the abundances of now extinct radioactivities (relative to stable reference isotopes) in meteorites vary as a function of their mean lifetimes squared. This relationship applies to chondrites, achondrites, and irons but to calcium-aluminum inclusions (CAIs). Certain meteorites contain excesses in isotopic abundances from the decay of radioactive isotopes with half-lives much less than the age of the solar system. These short-lived radioactivities are now extinct, but they were alive when meteorites assembled in the early solar system. The origin of these radioactivities and the processes which control their abundances in the solar nebula are still not well understood. Some clues may come from our finding that the meteoritic abundances of now extinct radioactivities (relative to stable reference isotopes) vary as a function of their mean lifetimes squared. This relationship applies to chondrites, achondrites, and irons, but not to CAIs. This points to at least two different processes establishing the abundances of short-lived isotopes found in the meteoritic record.

  8. ENHANCED ABUNDANCES IN SPIRAL GALAXIES OF THE PEGASUS I CLUSTER

    SciTech Connect

    Robertson, Paul; Shields, Gregory A.; Blanc, Guillermo A. E-mail: shields@astro.as.utexas.edu

    2012-03-20

    We study the influence of cluster environment on the chemical evolution of spiral galaxies in the Pegasus I cluster. We determine the gas-phase heavy element abundances of six galaxies in Pegasus derived from H II region spectra obtained from integral-field spectroscopy. These abundances are analyzed in the context of Virgo, whose spirals are known to show increasing interstellar metallicity as a function of H I deficiency. The galaxies in the Pegasus cluster, despite its lower density and velocity dispersion, also display gas loss due to interstellar-medium-intracluster-medium interaction, albeit to a lesser degree. Based on the abundances of three H I deficient spirals and two H I normal spirals, we observe a heavy element abundance offset of +0.13 {+-} 0.07 dex for the H I deficient galaxies. This abundance differential is consistent with the differential observed in Virgo for galaxies with a similar H I deficiency, and we observe a correlation between log (O/H) and the H I deficiency parameter DEF for the two clusters analyzed together. Our results suggest that similar environmental mechanisms are driving the heavy element enhancement in both clusters.

  9. Carbon and oxygen abundances across the Hertzsprung gap

    SciTech Connect

    Adamczak, Jens; Lambert, David L. E-mail: dll@astro.as.utexas.edu

    2014-08-10

    We derived atmospheric parameters and spectroscopic abundances for C and O for a large sample of stars located in the Hertzsprung gap in the Hertzsprung-Russell diagram in order to detect chemical peculiarities and get a comprehensive overview of the population of stars in this evolutionary state. We have observed and analyzed high-resolution spectra (R = 60,000) of 188 stars in the mass range 2-5 M{sub ☉} with the 2.7 m Harlan J. Smith Telescope at the McDonald Observatory including 28 stars previously identified as Am/Ap stars. We find that the C and O abundances of the majority of stars in the Hertzsprung gap are in accordance with abundances derived for local lower-mass dwarfs but detect expected peculiarities for the Am/Ap stars. The C and O abundances of stars with T{sub eff} < 6500 K are slightly lower than for the hotter objects but the C/O ratio is constant in the analyzed temperature domain. No indication of an alteration of the C and O abundances of the stars by mixing during the evolution across the Hertzsprung gap could be found before the homogenization of their atmospheres by the first dredge-up.

  10. Neon and Oxygen Absolute Abundances in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Landi, E.; Feldman, U.; Doschek, G. A.

    2007-04-01

    In the present work we use the UV spectrum of a solar flare observed with SOHO SUMER to measure the absolute abundance of Ne in the solar atmosphere. The measurement is carried out using the intensity ratio between the allowed 1s2s3S1-1s2p3P2 Ne IX line at 1248.28 Å and the free-free continuum radiation observed close to the Ne IX line. We find a value of the absolute Ne abundance ANe=8.11+/-0.12, in agreement with previous estimates but substantially higher than the very recent estimate by Asplund et al. based on the oxygen photospheric abundance and the Ne/O relative abundance. Considering our measured ANe value, we argue that the absolute oxygen abundance of Asplund et al. is too low by a factor 1.9. This result has important consequences for models of the solar interior based on helioseismology measurements, as well as on the FIP bias determination of the solar upper atmosphere, solar wind, and solar energetic particles.

  11. Carbon abundance and silicate mineralogy of anhydrous interplanetary dust particles

    NASA Technical Reports Server (NTRS)

    Thomas, Kathie L.; Blanford, George E.; Keller, Lindsay P.; Kloeck, Wolfgang; Mckay, David S.

    1993-01-01

    We have studied nineteen anhydrous chondritic interplanetary dust particles (IDPs) using analytical electron microscopy. We have determined a method for quantitative light element EDX analysis of small particles and have applied these techniques to a group of IDPs. Our results show that some IDPs have significantly higher bulk carbon abundances than do carbonaceous chondrites. We have also identified a relationship between carbon abundance and silicate mineralogy in our set of anhydrous IDPs. In general, these particles are dominated by pyroxene, olivine, or a subequal mixture of olivine and pyroxene. The pyroxene-dominated IDPs have a higher carbon abundance than those dominated by olivines. Members of the mixed mineralogy IDPs can be grouped with either the pyroxene- or olivine-dominated particles based on their carbon abundance. The high carbon, pyroxene-dominated particles have primitive mineralogies and bulk compositions which show strong similarities to cometary dust particles. We believe that the lower carbon, olivine-dominated IDPs are probably derived from asteroids. Based on carbon abundances, the mixed-mineralogy group represents particles derived from either comets or asteroids. We believe that the high carbon, pyroxene-rich anhydrous IDPs are the best candidates for cometary dust.

  12. Anomalous Oxygen and Krypton Abundances in Interstellar Gas

    NASA Technical Reports Server (NTRS)

    Meyer, David M.

    2004-01-01

    The primary objective of this program was to obtain FUSE observations of the interstellar H2 absorption toward a sample of stars observed with the HST STIS spectrograph as part of the ISM SNAP Survey. This Survey was designed to produce a database of high quality, high resolution W spectra from which interstellar gas-phase elemental abundances could be derived for large portions of the Galaxy. In particular, oxygen and krypton were chosen as excellent tracers for measuring the homogeneity of the interstellar gas due to their weak depletion into dust grains. The gas-phase 0 and Kr abundances relative to total hydrogen column density had previously been shown with HST GHRS measurements to be essentially constant in the local Milky Way. One of the main motivations of the ISM SNAP Survey was to determine if this constancy held at greater distances and in denser sightlines (where depletion into dust could be a possibility). The initial ISM SNAP STIS observations indicated a number of sightlines with unusual 0 and Kr abundances relative to the measured H I column densities. Since the appropriate benchmark for accurate abundance comparisons is the total hydrogen column density (H I plus H2), FUSE observations of interstellar H2 were carried out in these sightlines in order to determine if they represent cases of true abundance anomalies.

  13. ABUNDANCES IN THE LOCAL REGION. I. G AND K GIANTS

    SciTech Connect

    Luck, R. Earle

    2015-09-15

    Parameters and abundances for 1133 stars of spectral types F, G, and K of luminosity class III have been derived. In terms of stellar parameters, the primary point of interest is the disagreement between gravities derived with masses determined from isochrones, and gravities determined from an ionization balance. This is not a new result per se, but the size of this sample emphasizes the severity of the problem. A variety of arguments led to the selection of the ionization-balance gravity as the working value. The derived abundances indicate that the giants in the solar region have Sun-like total abundances and abundance ratios. Stellar evolution indicators have also been investigated with the Li abundances and the [C/Fe] and C/O ratios, indicating that standard processing has been operating in these stars. The more salient result for stellar evolution is that the [C/Fe] data across the red-giant clump indicates the presence of mass-dependent mixing in accord with standard stellar evolution predictions.

  14. The Chemical Abundances of White Dwarfs in CVS

    NASA Astrophysics Data System (ADS)

    Sion, Edward M.

    Dwarf novae and nova-like variables contain accreting white dwarfs which may have undergone numerous thermonuclear runaways as classical novae. In order to demonstrate their connection with novae however attempts have been made to detect ejected shells without success (references). However a new approach has recently emerged for systems in which the white dwarf photosphere has been detected spectroscopically. Sion et al. (1997) showed that the surface abundances of the white dwarf in VW Hydri during its quiescence manifests a direct evolutionary to a past thermonuclear event. This conclusion is based upon the presence of a large ratio of nitrogen to carbon abundance and the spectroscopic presence of odd-numbered proton-capture nuclei in abundances greatly elevated above solar. Both of these spectroscopic characteristics point to hot CNO processing as the source of the abundances. Other systems besides VW Hyi reveal further evidence of nova processing. This talk will review all of the determinations of surface chemical abundances of white dwarfs in cataclysmic variables both above and below the period gap and will discuss the implications for CV evolution and contributions to the heavy element content of the interstellar medium.

  15. Host densities as determinants of abundance in parasite communities

    PubMed Central

    Arneberg, P.; Skorping, A.; Grenfell, B.; Read, A. F.

    1998-01-01

    Several epidemiological models predict a positive relationship between host population density and abundance of directly transmitted macroparasites. Here, we generalize these, and test the prediction by a comparative study. We used data on communities of gastrointestinal strongylid nematodes from 19 mammalian species, representing examination of 6670 individual hosts. We studied both the average abundance of all strongylid nematodes within a host species, and the two components of abundance, prevalence and intensity. The effects of host body weight, diet, fecundity and age at maturity and parasite body size were controlled for directly, and the phylogenetically independent contrast method was used to control for confounding factors more generally. Host population density and average parasite abundance were strongly positively correlated within mammalian taxa, and across all species when the effects of host body weight were controlled for. Controlling for other variables did not change this. Even when looking at single parasite species occurring in several host species, abundance was highest in the host species with the highest population density. Prevalence and intensity showed similar patterns. These patterns provide the first macroecological evidence consistent with the prediction that transmission rates depend on host population density in natural parasite communities.

  16. Evaluating noninvasive genetic sampling techniques to estimate large carnivore abundance.

    PubMed

    Mumma, Matthew A; Zieminski, Chris; Fuller, Todd K; Mahoney, Shane P; Waits, Lisette P

    2015-09-01

    Monitoring large carnivores is difficult because of intrinsically low densities and can be dangerous if physical capture is required. Noninvasive genetic sampling (NGS) is a safe and cost-effective alternative to physical capture. We evaluated the utility of two NGS methods (scat detection dogs and hair sampling) to obtain genetic samples for abundance estimation of coyotes, black bears and Canada lynx in three areas of Newfoundland, Canada. We calculated abundance estimates using program capwire, compared sampling costs, and the cost/sample for each method relative to species and study site, and performed simulations to determine the sampling intensity necessary to achieve abundance estimates with coefficients of variation (CV) of <10%. Scat sampling was effective for both coyotes and bears and hair snags effectively sampled bears in two of three study sites. Rub pads were ineffective in sampling coyotes and lynx. The precision of abundance estimates was dependent upon the number of captures/individual. Our simulations suggested that ~3.4 captures/individual will result in a < 10% CV for abundance estimates when populations are small (23-39), but fewer captures/individual may be sufficient for larger populations. We found scat sampling was more cost-effective for sampling multiple species, but suggest that hair sampling may be less expensive at study sites with limited road access for bears. Given the dependence of sampling scheme on species and study site, the optimal sampling scheme is likely to be study-specific warranting pilot studies in most circumstances.

  17. Energy 101: Electric Vehicles

    SciTech Connect

    2012-01-01

    This edition of Energy 101 highlights the benefits of electric vehicles, including improved fuel efficiency, reduced emissions, and lower maintenance costs. For more information on electric vehicles from the Office of Energy Efficiency and Renewable Energy, visit the Vehicle Technologies Program website: http://www1.eere.energy.gov/vehiclesandfuels/

  18. Electric Vehicle Battery Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2014-01-01

    A serious drawback to electric vehicles [batteries only] is the idle time needed to recharge their batteries. In this challenge, students can develop ideas and concepts for battery change-out at automotive service stations. Such a capability would extend the range of electric vehicles.

  19. The Theory of Electricity

    NASA Astrophysics Data System (ADS)

    Livens, G. H.

    2016-10-01

    Preface; 1. The electric field; 2. Dielectric theory; 3. Electric currents; 4. The magnetic field; 5. The dynamics of the magnetic field; 6. Maxwell's electromagnetic theory; 7. Electromagnetic oscillations and waves; 8. The electrodynamics of moving media; Appendix 1. On the mechanism of magnetic induction; Appendix 2. On the mechanism of metallic conduction; Index.

  20. Renewable Electricity Futures (Presentation)

    SciTech Connect

    Hand, M.; Mai, T.

    2012-08-01

    This presentation library summarizes findings of NREL's Renewable Electricity Futures study, published in June 2012. RE Futures investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050. It was presented in an Union of Concerned Scientists webinar on June 12, 2012.

  1. Electric vehicles: Driving range

    NASA Astrophysics Data System (ADS)

    Kempton, Willett

    2016-09-01

    For uptake of electric vehicles to increase, consumers' driving-range needs must be fulfilled. Analysis of the driving patterns of personal vehicles in the US now shows that today's electric vehicles can meet all travel needs on almost 90% of days from a single overnight charge.

  2. Electric Propulsion Apparatus

    NASA Technical Reports Server (NTRS)

    Patterson, Michael J. (Inventor)

    2013-01-01

    An electric propulsion machine includes an ion thruster having an annular discharge chamber housing an anode having a large surface area. The ion thruster includes flat annular ion optics with a small span to gap ratio. Optionally, a second electric propulsion thruster may be disposed in a cylindrical space disposed within an interior of the annulus.

  3. Energy 101: Electric Vehicles

    ScienceCinema

    None

    2016-07-12

    This edition of Energy 101 highlights the benefits of electric vehicles, including improved fuel efficiency, reduced emissions, and lower maintenance costs. For more information on electric vehicles from the Office of Energy Efficiency and Renewable Energy, visit the Vehicle Technologies Program website: http://www1.eere.energy.gov/vehiclesandfuels/

  4. Aircraft Electric Secondary Power

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Technologies resulted to aircraft power systems and aircraft in which all secondary power is supplied electrically are discussed. A high-voltage dc power generating system for fighter aircraft, permanent magnet motors and generators for aircraft, lightweight transformers, and the installation of electric generators on turbine engines are among the topics discussed.

  5. Renewable Electricity Futures (Presentation)

    SciTech Connect

    Hand, M.

    2012-10-01

    This presentation library summarizes findings of NREL's Renewable Electricity Futures study, published in June 2012. RE Futures investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050. It is being presented at the Utility Variable-Generation Integration Group Fall Technical Workshop on October 24, 2012.

  6. Renewable Electricity Futures (Presentation)

    SciTech Connect

    Mai, T.

    2012-08-01

    This presentation summarizes findings of NREL's Renewable Electricity Futures study, published in June 2012. RE Futures investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050. This presentation was presented in a Wind Powering America webinar on August 15, 2012 and is now available through the Wind Powering America website.

  7. Renewable Electricity Futures (Presentation)

    SciTech Connect

    Mai, T.

    2012-08-01

    This presentation summarizes findings of NREL's Renewable Electricity Futures study, published in June 2012. RE Futures investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050. It was presented in a Power Systems Engineering Research Center webinar on September 4, 2012.

  8. Renewable Electricity Futures (Presentation)

    SciTech Connect

    Hand, M. M.

    2012-08-01

    This presentation library summarizes findings of NREL's Renewable Electricity Futures study, published in June 2012. RE Futures investigated the challenges and impacts of achieving very high renewable electricity generation levels in the contiguous United States by 2050. It was presented in a webinar given by the California Energy Commission.

  9. Multilayer flat electrical cable

    NASA Technical Reports Server (NTRS)

    Silverman, P. G.

    1973-01-01

    Flat electrical cable is lightweight, flexible over wide temperature range, withstands continuous exposure to high levels of nuclear radiation, and can carry high currents with minimum of temperature rise. Its magnetic cleanliness is equal to or better than twisted pair of wires, and it can be terminated in conventional electrical connector.

  10. Electricity and Its Use.

    ERIC Educational Resources Information Center

    Crank, Ron

    This instructional unit is one of 10 developed by students on various energy-related areas that deals specifically with the use of electricity. Its objective is for the student to be able to discuss consumer uses of electricity and understand increased usage and problems relating to needs for production expansion. Some topics covered are major…

  11. Electrically conductive diamond electrodes

    DOEpatents

    Swain, Greg; Fischer, Anne ,; Bennett, Jason; Lowe, Michael

    2009-05-19

    An electrically conductive diamond electrode and process for preparation thereof is described. The electrode comprises diamond particles coated with electrically conductive doped diamond preferably by chemical vapor deposition which are held together with a binder. The electrodes are useful for oxidation reduction in gas, such as hydrogen generation by electrolysis.

  12. Electric Power Monthly

    EIA Publications

    2017-01-01

    Provides monthly statistics at the state, Census division, and U.S. levels for net generation, fossil fuel consumption and stocks, quantity and quality of fossil fuels, cost of fossil fuels, electricity sales, revenue, and average revenue per kilowatthour of electricity sold.

  13. Efficient Use of Electricity.

    ERIC Educational Resources Information Center

    Fickett, Arnold P.; And Others

    1990-01-01

    Discussed are advanced technologies which may offer an opportunity to meet the world's future energy needs while minimizing the environmental impact. Savings to both suppliers and consumers are described. International electricity usage is compared. Government standards for the manufacture of electrical products in the United States are…

  14. Electric propulsion, circa 2000

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.; Finke, R. C.

    1980-01-01

    This paper discusses the future of electric propulsion, circa 2000. Starting with the first generation Solar Electric Propulsion (SEP) technology as the first step toward the next century's advanced propulsion systems, the current status and future trends of other systems such as the magnetoplasmadynamic accelerator, the mass driver, the laser propulsion system, and the rail gun are described.

  15. Problem Solving in Electricity.

    ERIC Educational Resources Information Center

    Caillot, Michel; Chalouhi, Elias

    Two studies were conducted to describe how students perform direct current (D-C) circuit problems. It was hypothesized that problem solving in the electricity domain depends largely on good visual processing of the circuit diagram and that this processing depends on the ability to recognize when two or more electrical components are in series or…

  16. Hawaii electric system reliability.

    SciTech Connect

    Silva Monroy, Cesar Augusto; Loose, Verne William

    2012-09-01

    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers' views of reliability %E2%80%9Cworth%E2%80%9D and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers' views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  17. Hawaii Electric System Reliability

    SciTech Connect

    Loose, Verne William; Silva Monroy, Cesar Augusto

    2012-08-01

    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers’ views of reliability “worth” and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers’ views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  18. Static and Current Electricity.

    ERIC Educational Resources Information Center

    Schlenker, Richard M.; Murtha, Kathy T.

    This is a copy of the script for the electrical relationships unit in an auto-tutorial physical science course for non-science majors, offered at the University of Maine at Orono. The unit includes 15 simple experiments designed to allow the student to discover various fundamental electrical relationships. The student has the option of reading the…

  19. Electrical Circuit Simulation Code

    SciTech Connect

    Wix, Steven D.; Waters, Arlon J.; Shirley, David

    2001-08-09

    Massively-Parallel Electrical Circuit Simulation Code. CHILESPICE is a massively-arallel distributed-memory electrical circuit simulation tool that contains many enhanced radiation, time-based, and thermal features and models. Large scale electronic circuit simulation. Shared memory, parallel processing, enhance convergence. Sandia specific device models.

  20. Electrical Work in Schools.

    ERIC Educational Resources Information Center

    Ontario Dept. of Education, Toronto. School Business and Finance Branch.

    Most buildings rely on electricity for lighting, power, signals, and other communications. Electric energy is also used for heating and year-round thermal conditioning of spaces. Its ease of transmission, simple control and measurement, and relative safety make it a useful source of energy. This publication is intended to provide those persons…