Science.gov

Sample records for abundance index empai

  1. 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

  2. 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.

  3. Line Profile Variations of Solar Analog Stars: Chromospheric Indexes vs. Li Abundance. The Host Star Search.

    NASA Astrophysics Data System (ADS)

    Amazo-Gómez, E. M.; Harutyunyan, G.; Alvarado-Gómez, J. D.; Strassmeier, K. G.; Weber, M.; Carroll, T. A.

    2015-10-01

    PolarBase contains stellar spectropolarimetric data collected with the NARVAL & ESPaDOnS instruments (Petit et al. 2014). Their respective spectral resolutions are 65 000 and 68 000, in spectropolarimetric mode. As the first part of this work, we use the NARVAL spectropolarimetric repositories. We selected spectra from a sample of cool stars with effective Temperature (T eff) ranging between 4900 to 6000 K. This sample contains stellar systems with and without reported exoplanets. We exploit the full wavelength range from 380 to 900 nm in order to obtain chromospheric indexes such as the Ca ii H&K S-Index, and a Ca ii IRT and Hα index. We calibrated our measurements using the Mount Wilson S-Index values. Furthermore, we employ lithium (Li) abundance measurements from the literature (Gonzalez et al. 2010; Delgado Mena et al. 2014; Israelian et al. 2004), investigating in this way a possible correlation between the chromospheric activity measurements and the Li abundance in 32 selected cool stars.

  4. Evaluating abundance estimate precision and the assumptions of a count-based index for small mammals

    USGS Publications Warehouse

    Wiewel, A.S.; Adams, A.A.Y.; Rodda, G.H.

    2009-01-01

    Conservation and management of small mammals requires reliable knowledge of population size. We investigated precision of markrecapture and removal abundance estimates generated from live-trapping and snap-trapping data collected at sites on Guam (n 7), Rota (n 4), Saipan (n 5), and Tinian (n 3), in the Mariana Islands. We also evaluated a common index, captures per unit effort (CPUE), as a predictor of abundance. In addition, we evaluated cost and time associated with implementing live-trapping and snap-trapping and compared species-specific capture rates of selected live- and snap-traps. For all species, markrecapture estimates were consistently more precise than removal estimates based on coefficients of variation and 95 confidence intervals. The predictive utility of CPUE was poor but improved with increasing sampling duration. Nonetheless, modeling of sampling data revealed that underlying assumptions critical to application of an index of abundance, such as constant capture probability across space, time, and individuals, were not met. Although snap-trapping was cheaper and faster than live-trapping, the time difference was negligible when site preparation time was considered. Rattus diardii spp. captures were greatest in Haguruma live-traps (Standard Trading Co., Honolulu, HI) and Victor snap-traps (Woodstream Corporation, Lititz, PA), whereas Suncus murinus and Mus musculus captures were greatest in Sherman live-traps (H. B. Sherman Traps, Inc., Tallahassee, FL) and Museum Special snap-traps (Woodstream Corporation). Although snap-trapping and CPUE may have utility after validation against more rigorous methods, validation should occur across the full range of study conditions. Resources required for this level of validation would likely be better allocated towards implementing rigorous and robust methods.

  5. Nonlinearity and seasonal bias in an index of brushtail possum abundance

    USGS Publications Warehouse

    Forsyth, D.M.; Link, W.A.; Webster, R.; Nugent, G.; Warburton, B.

    2005-01-01

    Introduced brushtail possums (Trichosurus vulpecula) are a widespread pest of conservation and agriculture in New Zealand, and considerable effort has been expended controlling populations to low densities. A national protocol for monitoring the abundance of possums, termed trap catch index (TCI), was adopted in 1996. The TCI requires that lines of leghold traps set at 20-m spacing are randomly located in a management area. The traps are set for 3 fine nights and checked daily, and possums are killed and traps reset. The TCI is the mean percentage of trap nights that possums were caught, corrected for sprung traps and nontarget captures, with trap line as the sampling unit. We studied I forest and I farmland area in the North Island, New Zealand, to address concerns that TCI estimates may not be readily comparable because of seasonal changes in the capture probability of possums. We located blocks of 6 trap lines at each area and randomly trapped I line in each block in 3 seasons (summer, winter, and spring) in 2000 and 2001. We developed a model to allow for variation in local population size and nightly capture probability, and fitted the model using the Bayesian analysis software BUGS. Capture probability declined with increasing abundance of possums, generating a nonlinear TCI. Capture probability in farmland was lower during spring relative to winter and summer, and to forest during summer. In the absence of a proven and cost-effective alternative, our results support the continued use of the TCI for monitoring the abundance of possums in New Zealand. Seasonal biases in the TCI should be minimized by conducting repeat sampling in the same season.

  6. Data-poor management of African lion hunting using a relative index of abundance.

    PubMed

    Edwards, Charles T T; Bunnefeld, Nils; Balme, Guy A; Milner-Gulland, E J

    2014-01-07

    Sustainable management of terrestrial hunting requires managers to set quotas restricting offtake. This often takes place in the absence of reliable information on the population size, and as a consequence, quotas are set in an arbitrary fashion, leading to population decline and revenue loss. In this investigation, we show how an indirect measure of abundance can be used to set quotas in a sustainable manner, even in the absence of information on population size. Focusing on lion hunting in Africa, we developed a simple algorithm to convert changes in the number of safari days required to kill a lion into a quota for the following year. This was tested against a simulation model of population dynamics, accounting for uncertainties in demography, observation, and implementation. Results showed it to reliably set sustainable quotas despite these uncertainties, providing a robust foundation for the conservation of hunted species.

  7. Shotgun proteomics to unravel the complexity of the Leishmania infantum exoproteome and the relative abundance of its constituents.

    PubMed

    Braga, Micheline Soares; Neves, Leandro Xavier; Campos, Jonatan Marques; Roatt, Bruno Mendes; de Oliveira Aguiar Soares, Rodrigo Dian; Braga, Samuel Leôncio; de Melo Resende, Daniela; Reis, Alexandre Barbosa; Castro-Borges, William

    2014-06-01

    The exoproteome of some Leishmania species has revealed important insights into host-parasite interaction, paving the way for the proposal of novel disease-oriented interventions. The focus of the present investigation constituted the molecular profile of the L. infantum exoproteome revealed by a shotgun proteomic approach. Promastigotes under logarithmic phase of growth were obtained and harvested by centrifugation at different time points. Cell integrity was evaluated through the counting of viable parasites using propidium iodide labeling, followed by flow cytometry analysis. The 6h culture supernatant, operationally defined here as exoproteome, was then conditioned to in solution digestion and the resulting peptides submitted to mass spectrometry. A total of 102 proteins were identified and categorized according to their cellular function. Their relative abundance index (emPAI) allowed inference that the L. infantum exoproteome is a complex mixture dominated by molecules particularly involved in nucleotide metabolism and antioxidant activity. Bioinformatic analyses support that approximately 60% of the identified proteins are secreted, of which, 85% possibly reach the extracellular milieu by means of non-classic pathways. At last, sera from naturally infected animals, carriers of differing clinical forms of Canine Visceral Leishmaniasis (CVL), were used to test the immunogenicity associated to the L. infantum exoproteome. Western blotting experiments revealed that this sub-proteome was useful at discriminating symptomatic animals from those exhibiting other clinical forms of the disease. Collectively, the molecular characterization of the L. infantum exoproteome and the preliminary immunoproteomic assays opened up new research avenues related to treatment, prognosis and diagnosis of CVL.

  8. Modified spectral count index (mSCI) for estimation of protein abundance by protein relative identification possibility (RIPpro): a new proteomic technological parameter.

    PubMed

    Sun, Aihua; Zhang, Jiyang; Wang, Chunping; Yang, Dong; Wei, Handong; Zhu, Yunping; Jiang, Ying; He, Fuchu

    2009-11-01

    Peptides Count (SC) was widely used for protein abundance estimation in proteomics. On the basis of that, Mann and co-workers corrected the SC by dividing spectrum counts by the number of observable peptides per protein and named it PAI. Here we present modified spectral count index (mSCI) for protein abundance estimation, which was defined as the number of observed peptides divided by protein relative identification possibility (RIPpro). RIPpro was derived from 6788 mRNA and protein expression data (collected from human liver samples) and related to proteins' three physical and chemical properties (MW/pI/Hp). For 46 proteins in mouse neuro2a cells, mSCI shows a linear relationship with the actual protein concentration, similar or better than PAI abundance. Also, multiple linear regressions were performed to quantitative assess several factors' impact on the mRNA/protein abundance correlation. Our results shown that the primary factor affecting protein levels was mRNA abundance (32-37%), followed by variability in protein measurement, MW and protein turnover (7-12%,7-9% and 2-3%, respectively). Interestingly, we found that the concordance between mRNA transcripts and protein expression was not consistent among all protein functional categories. This correlation was lower for signaling proteins as compared to metabolism genes. It was determined that RIPpro was the primary factor affecting signaling protein abundance (23% on average), followed by mRNA abundance (17%). In contrast, only 5% (on average) of the variability of metabolic protein abundance was explained by RIPpro, much lower than mRNA abundance (40%). These results provide the impetus for further investigation of the biological significance of mechanisms regulating the mRNA/protein abundance correlation and provide additional insight into the relative importance of the technological parameter (RIPpro) in mRNA/protein correlation research.

  9. Indexing the relative abundance of age-0 white sturgeons in an impoundment of the lower Columbia River from highly skewed trawling data

    USGS Publications Warehouse

    Counihan, T.D.; Miller, A.I.; Parsley, M.J.

    1999-01-01

    The development of recruitment monitoring programs for age-0 white sturgeons Acipenser transmontanus is complicated by the statistical properties of catch-per-unit-effort (CPUE) data. We found that age-0 CPUE distributions from bottom trawl surveys violated assumptions of statistical procedures based on normal probability theory. Further, no single data transformation uniformly satisfied these assumptions because CPUE distribution properties varied with the sample mean (??(CPUE)). Given these analytic problems, we propose that an additional index of age-0 white sturgeon relative abundance, the proportion of positive tows (Ep), be used to estimate sample sizes before conducting age-0 recruitment surveys and to evaluate statistical hypothesis tests comparing the relative abundance of age-0 white sturgeons among years. Monte Carlo simulations indicated that Ep was consistently more precise than ??(CPUE), and because Ep is binomially rather than normally distributed, surveys can be planned and analyzed without violating the assumptions of procedures based on normal probability theory. However, we show that Ep may underestimate changes in relative abundance at high levels and confound our ability to quantify responses to management actions if relative abundance is consistently high. If data suggest that most samples will contain age-0 white sturgeons, estimators of relative abundance other than Ep should be considered. Because Ep may also obscure correlations to climatic and hydrologic variables if high abundance levels are present in time series data, we recommend ??(CPUE) be used to describe relations to environmental variables. The use of both Ep and ??(CPUE) will facilitate the evaluation of hypothesis tests comparing relative abundance levels and correlations to variables affecting age-0 recruitment. Estimated sample sizes for surveys should therefore be based on detecting predetermined differences in Ep, but data necessary to calculate ??(CPUE) should also be

  10. Immune indexes of larks from desert and temperate regions show weak associations with life history but stronger links to environmental variation in microbial abundance.

    PubMed

    Horrocks, Nicholas P C; Hegemann, Arne; Matson, Kevin D; Hine, Kathryn; Jaquier, Sophie; Shobrak, Mohammed; Williams, Joseph B; Tinbergen, Joost M; Tieleman, B Irene

    2012-01-01

    Immune defense may vary as a result of trade-offs with other life-history traits or in parallel with variation in antigen levels in the environment. We studied lark species (Alaudidae) in the Arabian Desert and temperate Netherlands to test opposing predictions from these two hypotheses. Based on their slower pace of life, the trade-off hypothesis predicts relatively stronger immune defenses in desert larks compared with temperate larks. However, as predicted by the antigen exposure hypothesis, reduced microbial abundances in deserts should result in desert-living larks having relatively weaker immune defenses. We quantified host-independent and host-dependent microbial abundances of culturable microbes in ambient air and from the surfaces of birds. We measured components of immunity by quantifying concentrations of the acute-phase protein haptoglobin, natural antibody-mediated agglutination titers, complement-mediated lysis titers, and the microbicidal ability of whole blood. Desert-living larks were exposed to significantly lower concentrations of airborne microbes than temperate larks, and densities of some bird-associated microbes were also lower in desert species. Haptoglobin concentrations and lysis titers were also significantly lower in desert-living larks, but other immune indexes did not differ. Thus, contrary to the trade-off hypothesis, we found little evidence that a slow pace of life predicted increased immunological investment. In contrast, and in support of the antigen exposure hypothesis, associations between microbial exposure and some immune indexes were apparent. Measures of antigen exposure, including assessment of host-independent and host-dependent microbial assemblages, can provide novel insights into the mechanisms underlying immunological variation.

  11. 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.

  12. Author Indexing.

    ERIC Educational Resources Information Center

    Diodato, Virgil P.

    1981-01-01

    Discusses the effectiveness of using author-supplied indexing to increase subject control in information retrieval, and describes a study which compared author indexing for articles published in "American Mathematical Society" journals to indexing of the same articles by an editor of "Mathematical Reviews." Nine references are…

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. INDEXING MECHANISM

    DOEpatents

    Kock, L.J.

    1959-09-22

    A device is presented for loading and unloading fuel elements containing material fissionable by neutrons of thermal energy. The device comprises a combination of mechanical features Including a base, a lever pivotally attached to the base, an Indexing plate on the base parallel to the plane of lever rotation and having a plurality of apertures, the apertures being disposed In rows, each aperture having a keyway, an Index pin movably disposed to the plane of lever rotation and having a plurality of apertures, the apertures being disposed in rows, each aperture having a keyway, an index pin movably disposed on the lever normal to the plane rotation, a key on the pin, a sleeve on the lever spaced from and parallel to the index pin, a pair of pulleys and a cable disposed between them, an open collar rotatably attached to the sleeve and linked to one of the pulleys, a pin extending from the collar, and a bearing movably mounted in the sleeve and having at least two longitudinal grooves in the outside surface.

  18. CORRELATION OF RED-SHOULDERED HAWK ABUNDANCE AND MACROHABITAT CHARACTERISTICS IN SOUTHERN OHIO

    EPA Science Inventory

    We measured an index of Red-shouldered Hawk (Buteo lineatus) abundance along streams in southern Ohio and related differences in abundance index to landscape scale habitat characteristics within the surveyed areas. Fifteen study sites, each a 5.8-km reach of permanent stream, we...

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. WANTED: Fully Automated Indexing.

    ERIC Educational Resources Information Center

    Purcell, Royal

    1991-01-01

    Discussion of indexing focuses on the possibilities of fully automated indexing. Topics discussed include controlled indexing languages such as subject heading lists and thesauri, free indexing languages, natural indexing languages, computer-aided indexing, expert systems, and the need for greater creativity to further advance automated indexing.…

  5. The NLM Indexing Initiative's Medical Text Indexer.

    PubMed

    Aronson, Alan R; Mork, James G; Gay, Clifford W; Humphrey, Susanne M; Rogers, Willie J

    2004-01-01

    The Medical Text Indexer (MTI) is a program for producing MeSH indexing recommendations. It is the major product of NLM's Indexing Initiative and has been used in both semi-automated and fully automated indexing environments at the Library since mid 2002. We report here on an experiment conducted with MEDLINE indexers to evaluate MTI's performance and to generate ideas for its improvement as a tool for user-assisted indexing. We also discuss some filtering techniques developed to improve MTI's accuracy for use primarily in automatically producing the indexing for several abstracts collections.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. Indexing Consistency and Quality.

    ERIC Educational Resources Information Center

    Zunde, Pranas; Dexter, Margaret E.

    A measure of indexing consistency is developed based on the concept of 'fuzzy sets'. It assigns a higher consistency value if indexers agree on the more important terms than if they agree on less important terms. Measures of the quality of an indexer's work and exhaustivity of indexing are also proposed. Experimental data on indexing consistency…

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. Nucleic acid indexing

    DOEpatents

    Guilfoyle, Richard A.; Guo, Zhen

    1999-01-01

    A restriction site indexing method for selectively amplifying any fragment generated by a Class II restriction enzyme includes adaptors specific to fragment ends containing adaptor indexing sequences complementary to fragment indexing sequences near the termini of fragments generated by Class II enzyme cleavage. A method for combinatorial indexing facilitates amplification of restriction fragments whose sequence is not known.

  1. Nucleic acid indexing

    DOEpatents

    Guilfoyle, Richard A.; Guo, Zhen

    2001-01-01

    A restriction site indexing method for selectively amplifying any fragment generated by a Class II restriction enzyme includes adaptors specific to fragment ends containing adaptor indexing sequences complementary to fragment indexing sequences near the termini of fragments generated by Class II enzyme cleavage. A method for combinatorial indexing facilitates amplification of restriction fragments whose sequence is not known.

  2. Breeding chorus indices are weakly related to estimated abundance of boreal chorus frogs

    USGS Publications Warehouse

    Corn, P.S.; Muths, E.; Kissel, A.M.; Scherer, R. D.

    2011-01-01

    Call surveys used to monitor breeding choruses of anuran amphibians generate index values that are frequently used to represent the number of male frogs present, but few studies have quantified this relationship. We compared abundance of male Boreal Chorus Frogs (Pseudacris maculata), estimated using capture–recapture methods in two populations in Colorado, to call index values derived from automated recordings. Single index values, such as might result from large monitoring efforts, were unrelated to population size. A synthetic call saturation index (CSI), the daily proportion of the maximum possible sum of index values derived from multiple recordings, was greater in larger populations, but the relationship was not highly predictive.

  3. 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.

  4. 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.

  5. 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.

  6. Automating Index Preparation

    DTIC Science & Technology

    1987-03-23

    Automating Index Preparation* Pehong Chent Michael A. Harrison Computer Science Division University of CaliforniaI Berkeley, CA 94720 March 23, 1987...Abstract Index preparation is a tedious and time-consuming task. In this paper we indicate * how the indexing process can be automated in a way which...identified and analyzed. Specifically, we describe a framework for placing index commands in the document and a general purpose index processor which

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. CENDI Indexing Workshop

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The CENDI Indexing Workshop held at NASA Headquarters, Two Independence Square, 300 E Street, Washington, DC, on September 21-22, 1994 focused on the following topics: machine aided indexing, indexing quality, an indexing pilot project, the MedIndEx Prototype, Department of Energy/Office of Scientific and Technical Information indexing activities, high-tech coding structures, category indexing schemes, and the Government Information Locator Service. This publication consists mostly of viewgraphs related to the above noted topics. In an appendix is a description of the Government Information Locator Service.

  14. 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.

  15. 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.

  16. The NLM Indexing Initiative.

    PubMed

    Aronson, A R; Bodenreider, O; Chang, H F; Humphrey, S M; Mork, J G; Nelson, S J; Rindflesch, T C; Wilbur, W J

    2000-01-01

    The objective of NLM's Indexing Initiative (IND) is to investigate methods whereby automated indexing methods partially or completely substitute for current indexing practices. The project will be considered a success if methods can be designed and implemented that result in retrieval performance that is equal to or better than the retrieval performance of systems based principally on humanly assigned index terms. We describe the current state of the project and discuss our plans for the future.

  17. Gradient Index Lens Research

    DTIC Science & Technology

    1981-10-19

    Finally, an assessment of the current technologies in gradient index has been made. This includes a series of recommendations w’iich will be...17 III. Ray Tracing in Anamorphic Gradient Index Media ......... 20 IV. Fabrication of Six Gradient Index Samples ............. 27 V. Technology ...for a basic understanding of what can and cannot be done with gradient index lenses, aside from any lack of technology for making a paricular gradient

  18. Kaiser's Systematic Indexing.

    ERIC Educational Resources Information Center

    Rodriguez, Robert D.

    1984-01-01

    Describes a system of subject indexing developed by Julius Kaiser (1868-1927) which is based on "concretes" and "processes" to govern the form of subject headings and subdivisions. Elements of amplification, guides for the subject index, and criticism of Kaiser's systematic indexing are noted. Five sources are given. (EJS)

  19. Automatic Versus Manual Indexing

    ERIC Educational Resources Information Center

    Vander Meulen, W. A.; Janssen, P. J. F. C.

    1977-01-01

    A comparative evaluation of results in terms of recall and precision from queries submitted to systems with automatic and manual subject indexing. Differences were attributed to query formulation. The effectiveness of automatic indexing was found equivalent to manual indexing. (Author/KP)

  20. The Europe 2020 Index

    ERIC Educational Resources Information Center

    Pasimeni, Paolo

    2013-01-01

    This paper presents a new index to quantify, measure and monitor the progress towards the objectives of the Europe 2020 strategy. This index is based on a set of relevant, accepted, credible, easy to monitor and robust indicators presented by the European Commission at the time the strategy was launched. The internal analysis of the index shows…

  1. 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.

  2. 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.

  3. 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

  4. Performance of Baited Underwater Video: Does It Underestimate Abundance at High Population Densities?

    PubMed Central

    Stobart, Ben; Díaz, David; Álvarez, Federico; Alonso, Cristina; Mallol, Sandra; Goñi, Raquel

    2015-01-01

    Video survey techniques are now commonly used to estimate animal abundance under the assumption that estimates relate to true abundance, a key property needed to make video a valid survey tool. Using the spiny lobster Palinurus elephas as our model organism, we evaluate the effectiveness of baited underwater video (BUV) for estimating abundance in areas with widely different population density. We test three BUV abundance metrics and compare the results with an independently obtained abundance index from trammel-net surveys (Trammel). Video metrics used to estimate relative abundance include a value for total number of individuals per recording (TotN), the traditional maximum number of fish observed in a single video frame (MaxN), and the recently suggested alternative, the average of the mean MaxN from 5-minute periods throughout the duration of the recording (MeanN). This is the first video study of a wild population to include an estimate for TotN. Comparison of TotN with the other two BUV relative abundance metrics demonstrates that both of the latter lack resolution at high population densities. In spite of this, the three BUV metrics tested, as well as the independent estimate Trammel, distinguished high density areas from low density areas. Thus they could all be used to identify areas of differing population density, but MaxN and MeanN would not be appropriate metrics for studies aimed at documenting increases in abundance, such as those conducted to assess marine protected area effectiveness, as they are prone to sampling saturation. We also demonstrate that time of first arrival (T1) is highly correlated with all of the abundance indices; suggesting T1 may be a potentially useful index of abundance. However, these relationships require further investigation as our data suggests T1 may not adequately represent lobster abundance in areas of high density. PMID:26010738

  5. Performance of baited underwater video: does it underestimate abundance at high population densities?

    PubMed

    Stobart, Ben; Díaz, David; Álvarez, Federico; Alonso, Cristina; Mallol, Sandra; Goñi, Raquel

    2015-01-01

    Video survey techniques are now commonly used to estimate animal abundance under the assumption that estimates relate to true abundance, a key property needed to make video a valid survey tool. Using the spiny lobster Palinurus elephas as our model organism, we evaluate the effectiveness of baited underwater video (BUV) for estimating abundance in areas with widely different population density. We test three BUV abundance metrics and compare the results with an independently obtained abundance index from trammel-net surveys (Trammel). Video metrics used to estimate relative abundance include a value for total number of individuals per recording (TotN), the traditional maximum number of fish observed in a single video frame (MaxN), and the recently suggested alternative, the average of the mean MaxN from 5-minute periods throughout the duration of the recording (MeanN). This is the first video study of a wild population to include an estimate for TotN. Comparison of TotN with the other two BUV relative abundance metrics demonstrates that both of the latter lack resolution at high population densities. In spite of this, the three BUV metrics tested, as well as the independent estimate Trammel, distinguished high density areas from low density areas. Thus they could all be used to identify areas of differing population density, but MaxN and MeanN would not be appropriate metrics for studies aimed at documenting increases in abundance, such as those conducted to assess marine protected area effectiveness, as they are prone to sampling saturation. We also demonstrate that time of first arrival (T1) is highly correlated with all of the abundance indices; suggesting T1 may be a potentially useful index of abundance. However, these relationships require further investigation as our data suggests T1 may not adequately represent lobster abundance in areas of high density.

  6. 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.

  7. Cost Index Flying

    DTIC Science & Technology

    2011-06-01

    continually alter applicable cost indexes . Computed KC-10 Cost Index Equation Using the dollar figures given above, our CI equation reads : CI = CT / C...COST INDEX FLYING GRADUATE RESEARCH PAPER John M. Mirtich, Major, USAF AFIT/IMO/ENS/11-11 DEPARTMENT OF THE AIR FORCE AIR UNIVERSITY...AIR FORCE INSTITUTE OF TECHNOLOGY Wright-Patterson Air Force Base, Ohio APPROVED FOR PUBLIC RELEASE: DISTRIBUTION UNLIMITED

  8. The dimensions of indexing.

    PubMed

    Wilbur, W John; Kim, Won

    2003-01-01

    Indexing of documents is an important strategy intended to make the literature more readily available to the user. Here we describe several dimensions of indexing that are important if indexing is to be optimal. These dimensions are coverage, predictability, and transparency. MeSH terms and text words are compared in MEDLINE in regard to these dimensions. Part of our analysis consists in applying AdaBoost with decisions trees as the weak learners to estimate how reliably index terms are being assigned and how complex the criteria are by which they are being assigned. Our conclusions are that MeSH terms are more predictable and more transparent than text words.

  9. Indexing for Invention.

    ERIC Educational Resources Information Center

    Breton, Ernest J.

    1991-01-01

    Describes the development of a functional indexing system that is tailored to the thinking involved in the process of invention. Classification by function is discussed; matrix representation is explained; a controlled vocabulary of verbs, objects, and modifiers is described; and the relation to other indexing systems is examined. (13 references)…

  10. Indexing Editorial Cartoons.

    ERIC Educational Resources Information Center

    Chapple-Sokol, Angie

    1996-01-01

    Discusses access to editorial cartoons, including the importance and worth of editorial cartoons; sources, including newspapers, museums, and special cartoon collections; indexing and classification; subject access; indexing by illustrator and subject; technology and access, including digital data; access to special collections; and access to…

  11. Linked Phrase Indexing.

    ERIC Educational Resources Information Center

    Craven, Timothy C.

    1978-01-01

    Describes a computer-assisted system for the production of printed indexes based on networks of concept relations expressed in natural-language-like form. The LIPHIS is designed to handle more complex networks of concept relations, and so produce better indexing of highly detailed subjects. (Author/CWM)

  12. EMMSE Media Index.

    ERIC Educational Resources Information Center

    Hewitt, Clifford A., Comp.; McKinstry, Herbert A., Comp.

    This index provides a topical taxonomy of media which have been selected for their relevance in the teaching of materials science and engineering. The index is keyed to a matrix which matches topical and/or class material with six classifications of media: print, 16mm film, super 8 film, slide/tape, videotape, and other (including interactive…

  13. A Computer Calculated Index.

    ERIC Educational Resources Information Center

    Brown, Francis J.

    The Gunning Fog Index of readability indicates both the average length of words and the difficult words (three or more syllables) in written material. This document describes a business communication course at Wayne State University in which students calculate the Gunning Fog Index of two of their writing assignments with the aid of the…

  14. Transfer Index: One Definition.

    ERIC Educational Resources Information Center

    Heinselman, James L.

    A transfer index of the proportion of students in California's community colleges transferring to the University of California (UC) and the California State University (CSU) system for fall 1982, 1983, and 1984 is presented in this report. Introductory material provides one definition of an appropriate index of transfer rates, i.e., the ratio of…

  15. Universal Index System

    NASA Technical Reports Server (NTRS)

    Kelley, Steve; Roussopoulos, Nick; Sellis, Timos; Wallace, Sarah

    1993-01-01

    The Universal Index System (UIS) is an index management system that uses a uniform interface to solve the heterogeneity problem among database management systems. UIS provides an easy-to-use common interface to access all underlying data, but also allows different underlying database management systems, storage representations, and access methods.

  16. Children's Stress Index.

    ERIC Educational Resources Information Center

    Sherman, Dianne, Ed.

    1993-01-01

    This double issue of the "ZPG Reporter" focuses on the theme of ZPG's Children's Stress Index", the first national survey of children's well-being based on population- related pressures. Using an extensive list of social, economic, and environmental factors that affect the lives of children, the index ranks 828 cities, counties, and…

  17. A Factor Simplicity Index.

    ERIC Educational Resources Information Center

    Lorenzo-Seva, Urbano

    2003-01-01

    Proposes an index for assessing the degree of factor simplicity in the context of principal components and exploratory factor analysis. The index does not depend on the scale of the factors, and its maximum and minimum are related only to the degree of simplicity in the loading matrix. (SLD)

  18. Gradient index retroreflector

    DOEpatents

    Layne, Clyde B.

    1988-01-01

    A retroreflector is formed of a graded index lens with a reflective coating at one end. The lens has a length of an odd multiple of a quarter period thereof. Hexagonally shaped graded index lenses may be closely packed in an array to form a retroreflecting surface.

  19. 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

  20. 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.

  1. 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.

  2. Null model analysis of species associations using abundance data.

    PubMed

    Ulrich, Werner; Gotelli, Nicholas J

    2010-11-01

    The influence of negative species interactions has dominated much of the literature on community assembly rules. Patterns of negative covariation among species are typically documented through null model analyses of binary presence/absence matrices in which rows designate species, columns designate sites, and the matrix entries indicate the presence (1) or absence (0) of a particular species in a particular site. However, the outcome of species interactions ultimately depends on population-level processes. Therefore, patterns of species segregation and aggregation might be more clearly expressed in abundance matrices, in which the matrix entries indicate the abundance or density of a species in a particular site. We conducted a series of benchmark tests to evaluate the performance of 14 candidate null model algorithms and six covariation metrics that can be used with abundance matrices. We first created a series of random test matrices by sampling a metacommunity from a lognormal species abundance distribution. We also created a series of structured matrices by altering the random matrices to incorporate patterns of pairwise species segregation and aggregation. We next screened each algorithm-index combination with the random and structured matrices to determine which tests had low Type I error rates and good power for detecting segregated and aggregated species distributions. In our benchmark tests, the best-performing null model does not constrain species richness, but assigns individuals to matrix cells proportional to the observed row and column marginal distributions until, for each row and column, total abundances are reached. Using this null model algorithm with a set of four covariance metrics, we tested for patterns of species segregation and aggregation in a collection of 149 empirical abundance matrices and 36 interaction matrices collated from published papers and posted data sets. More than 80% of the matrices were significantly segregated, which

  3. Species richness, equitability, and abundance of ants in disturbed landscapes

    USGS Publications Warehouse

    Graham, J.H.; Krzysik, A.J.; Kovacic, D.A.; Duda, J.J.; Freeman, D.C.; Emlen, J.M.; Zak, J.C.; Long, W.R.; Wallace, M.P.; Chamberlin-Graham, C.; Nutter, J.P.; Balbach, H.E.

    2009-01-01

    Ants are used as indicators of environmental change in disturbed landscapes, often without adequate understanding of their response to disturbance. Ant communities in the southeastern United States displayed a hump-backed species richness curve against an index of landscape disturbance. Forty sites at Fort Benning, in west-central Georgia, covered a spectrum of habitat disturbance (military training and fire) in upland forest. Sites disturbed by military training had fewer trees, less canopy cover, more bare ground, and warmer, more compact soils with shallower A-horizons. We sampled ground-dwelling ants with pitfall traps, and measured 15 habitat variables related to vegetation and soil. Ant species richness was greatest with a relative disturbance of 43%, but equitability was greatest with no disturbance. Ant abundance was greatest with a relative disturbance of 85%. High species richness at intermediate disturbance was associated with greater within-site spatial heterogeneity. Species richness was also associated with intermediate values of the normalized difference vegetation index (NDVI), a correlate of net primary productivity (NPP). Available NPP (the product of NDVI and the fraction of days that soil temperature exceeded 25 ??C), however, was positively correlated with species richness, though not with ant abundance. Species richness was unrelated to soil texture, total ground cover, and fire frequency. Ant species richness and equitability are potential state indicators of the soil arthropod community. Moreover, equitability can be used to monitor ecosystem change. ?? 2008 Elsevier Ltd.

  4. Potential vorticity index

    NASA Technical Reports Server (NTRS)

    Barcilon, Albert; Weng, Hengyi

    1990-01-01

    Using standard data analysis techniques, researchers explore the links between disturbance growth and quasi-geostrophic potential vorticity (PV) gradients; appearance and disappearance of cutoff lows and blocking highs and their relation to a zonal index (properly defined in terms of PV); and teleconnections between different flow patterns and their relation to the zonal index. It was found that the PV index and the eddy index correlate better than a zonal index (defined by zonal wind) and the eddy index. In the frequency domain there are three frequencies (.03, .07 and .17 cpd (cycle per day) corresponding to periods of 33, 14 and 6 days) at which PV index and the eddy index exhibit local maxima. The high correlation found at periods of 33 days is mainly due to eddy activity at high latitudes while the local correlation maxima found at the shorter periods are mainly due mid-latitude eddy activity. The correlation between the PV index and the geopotential height anomaly at 500 mb, at each grid point in the Northern Hemisphere, shows the existence of most of the teleconnection patterns summarized by Wallace and Gutzler (1981): the North Atlantic Oscillation, the North Pacific Oscillation, and the Pacific/North American patterns. Results show that the Isentropic Potential Vorticity (IPV) analysis can be a very useful and powerful tool when used to understand the dynamics of several large scale atmospheric systems. Although the data are limited to only one winter, and it is difficult to assess the statistical significance of the correlation coefficients presented here, the results are encouraging from physical viewpoint.

  5. Index Construction, A Bibliography.

    DTIC Science & Technology

    1984-09-01

    Application in Science, S5G37 Technology , and Humanities, N.Y., N.Y: John Wiley & Sons, C 1969. Z695.9 Harrod, Leonard Montague, ed. Indexers on... Indexing Terminology, Posting Terms and KWOC, DESK Alexandria, VA: DDC, May, 1979. Z1035.1 Library of Congress. Main Reading Room, Reference Collection...A1544 750 INDEX CONSTRUCTON AR BI OGRAPHYU ARMY FIEL ARTILERY SHOOL FORT SIL OR MILE R SEP 84 USA FASM -DSB- A0 VNtASIIEFG 5/2 NI MONSOONSfl 0841

  6. Glycemic index and disease.

    PubMed

    Pi-Sunyer, F Xavier

    2002-07-01

    It has been suggested that foods with a high glycemic index are detrimental to health and that healthy people should be told to avoid these foods. This paper takes the position that not enough valid scientific data are available to launch a public health campaign to disseminate such a recommendation. This paper explores the glycemic index and its validity and discusses the effect of postprandial glucose and insulin responses on food intake, obesity, type 1 diabetes, and cardiovascular disease. Presented herein are the reasons why it is premature to recommend that the general population avoid foods with a high glycemic index.

  7. Genetic diversity in aspen and its relation to arthropod abundance.

    PubMed

    Zhang, Chunxia; Vornam, Barbara; Volmer, Katharina; Prinz, Kathleen; Kleemann, Frauke; Köhler, Lars; Polle, Andrea; Finkeldey, Reiner

    2014-01-01

    The ecological consequences of biodiversity have become a prominent public issue. Little is known on the effect of genetic diversity on ecosystem services. Here, a diversity experiment was established with European and North American aspen (Populus tremula, P. tremuloides) planted in plots representing either a single deme only or combinations of two, four and eight demes. The goals of this study were to explore the complex inter- and intraspecific genetic diversity of aspen and to then relate three measures for diversity (deme diversity, genetic diversity determined as Shannon index or as expected heterozygosity) to arthropod abundance. Microsatellite and AFLP markers were used to analyze the genetic variation patterns within and between the aspen demes and deme mixtures. Large differences were observed regarding the genetic diversity within demes. An analysis of molecular variance revealed that most of the total genetic diversity was found within demes, but the genetic differentiation among demes was also high. The complex patterns of genetic diversity and differentiation resulted in large differences of the genetic variation within plots. The average diversity increased from plots with only one deme to plots with two, four, and eight demes, respectively and separated plots with and without American aspen. To test whether intra- and interspecific diversity impacts on ecosystem services, arthropod abundance was determined. Increasing genetic diversity of aspen was related to increasing abundance of arthropods. However, the relationship was mainly driven by the presence of American aspen suggesting that species identity overrode the effect of intraspecific variation of European aspen.

  8. 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

  9. 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.

  10. 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.

  11. NASA 1981 photography index

    NASA Technical Reports Server (NTRS)

    1982-01-01

    An index of representative photographs is presented. Color transparencies and black and white glossies of major launches, Mariner spacecraft, Pioneer spacecraft, planets and other space phenomena, Skylab, space shuttle, Viking spacecraft, and Voyager spacecraft are included.

  12. Pesticide Use Site Index

    EPA Pesticide Factsheets

    The Pesticide Use Site Index will help a company (or other applicant) identify which data requirements are needed to register a pesticide product. It provides information on pesticide use sites and pesticide major use patterns.

  13. 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

  14. Gradient Index Lens Research.

    DTIC Science & Technology

    1982-11-25

    over six to nine readings at two to three input polarizations each. The first set of index values is calculated assuming ei = 450 These values are...TECHNICAL REPORT RG-CR-84-2 Sli GRADIENT INDEX LENS RESEARCH Prepared by: Duncan T. Moore The Institute of Optics University of Rochester Rochester...CLASSIFICATION OF THIS PAGE (Miten Data Fntered) READ INSTRUCTIONSREPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM 1. REPORT NU14MU R GOVT ACCESSION No. 3

  15. JSC document index

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Johnson Space Center (JSC) document index is intended to provide a single source listing of all published JSC-numbered documents their authors, and the designated offices of prime responsibility (OPR's) by mail code at the time of publication. The index contains documents which have been received and processed by the JSC Technical Library as of January 13, 1988. Other JSC-numbered documents which are controlled but not available through the JSC Library are also listed.

  16. New generic indexing technology

    NASA Technical Reports Server (NTRS)

    Freeston, Michael

    1996-01-01

    There has been no fundamental change in the dynamic indexing methods supporting database systems since the invention of the B-tree twenty-five years ago. And yet the whole classical approach to dynamic database indexing has long since become inappropriate and increasingly inadequate. We are moving rapidly from the conventional one-dimensional world of fixed-structure text and numbers to a multi-dimensional world of variable structures, objects and images, in space and time. But, even before leaving the confines of conventional database indexing, the situation is highly unsatisfactory. In fact, our research has led us to question the basic assumptions of conventional database indexing. We have spent the past ten years studying the properties of multi-dimensional indexing methods, and in this paper we draw the strands of a number of developments together - some quite old, some very new, to show how we now have the basis for a new generic indexing technology for the next generation of database systems.

  17. Monitoring the abundance of plastic debris in the marine environment

    PubMed Central

    Ryan, Peter G.; Moore, Charles J.; van Franeker, Jan A.; Moloney, Coleen L.

    2009-01-01

    Plastic debris has significant environmental and economic impacts in marine systems. Monitoring is crucial to assess the efficacy of measures implemented to reduce the abundance of plastic debris, but it is complicated by large spatial and temporal heterogeneity in the amounts of plastic debris and by our limited understanding of the pathways followed by plastic debris and its long-term fate. To date, most monitoring has focused on beach surveys of stranded plastics and other litter. Infrequent surveys of the standing stock of litter on beaches provide crude estimates of debris types and abundance, but are biased by differential removal of litter items by beachcombing, cleanups and beach dynamics. Monitoring the accumulation of stranded debris provides an index of debris trends in adjacent waters, but is costly to undertake. At-sea sampling requires large sample sizes for statistical power to detect changes in abundance, given the high spatial and temporal heterogeneity. Another approach is to monitor the impacts of plastics. Seabirds and other marine organisms that accumulate plastics in their stomachs offer a cost-effective way to monitor the abundance and composition of small plastic litter. Changes in entanglement rates are harder to interpret, as they are sensitive to changes in population sizes of affected species. Monitoring waste disposal on ships and plastic debris levels in rivers and storm-water runoff is useful because it identifies the main sources of plastic debris entering the sea and can direct mitigation efforts. Different monitoring approaches are required to answer different questions, but attempts should be made to standardize approaches internationally. PMID:19528052

  18. Heavy-Element Abundances in Solar Energetic Particle Events

    NASA Technical Reports Server (NTRS)

    Reames, D. V.; Ng, C. K.

    2004-01-01

    We survey the relative abundances of elements with 1 < or equal to Z < or equal to 82 in solar energetic particle (SEP) events observed at 2-10 MeV/amu during nearly 9 years aboard the Wind spacecraft, with special emphasis on enhanced abundances of elements with Z > or equal to 34. Abundances of Fe/O again show a bimodal distribution with distinct contributions from impulsive and gradual SEP events as seen in earlier solar cycles. Periods with greatly enhanced abundances of (50 < or equal to Z < or equal to 56)/O, like those with enhanced (3)He/(4)He, fall prominently in the Fe-rich population of the impulsive SEP events. In a sample of the 39 largest impulsive events, 25 have measurable enhancements in (50 < or equal to z < or equal to 56)/O and (76 < or equal to Z < or equal to 82)/O, relative to coronal values, ranging from approx. 100 to 10,000. By contrast, in a sample of 45 large gradual events the corresponding enhancements vary from approx. 0.2 to 20. However, the magnitude of the heavy-element enhancements in impulsive events is less striking than their strong correlation with the Fe spectral index and flare size, with the largest enhancements occurring in flares with the steepest Fe spectra, the smallest Fe fluence, and the lowest X-ray intensity, as reported here for the first time. Thus it seems that small events with low energy input can produce only steep spectra of the dominant species but accelerate rare heavy elements with great efficiency, probably by selective absorption of resonant waves in the flare plasma. With increased energy input, enhancements diminish, as heavy ions are depleted, and spectra of the dominant species harden.

  19. 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.

  20. Needs for Research in Indexing.

    ERIC Educational Resources Information Center

    Milstead, Jessica L.

    1994-01-01

    Uncovers issues in indexing that need scientific research, including the cognitive processes of indexers and users; vocabulary control; how best to supplement human indexers' intellectual effort with computer capabilities; structure and layout of indexes on the printed page and on the computer screen; and evaluation of indexes. (Contains 21…

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Quarantine document system indexing procedure

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The Quarantine Document System (QDS) is described including the indexing procedures and thesaurus of indexing terms. The QDS consists of these functional elements: acquisition, cataloging, indexing, storage, and retrieval. A complete listing of the collection, and the thesaurus are included.

  6. Beyond the Kubler index

    USGS Publications Warehouse

    Eberl, D.D.; Velde, B.

    1989-01-01

    The value of peak width at half-height for the illite 001 XRD reflection is known as the Kubler index or the illite "crystallinity' index. This measurement, which has been related to the degree of metamorphism of very low-grade, pelitic rocks, is a function of at least two crystal-chemical factors: 1) illite X-ray scattering domain size; and 2) illite structural distortions (especially swelling). Reynolds' NEWMOD computer program is used to construct a grid with which these two contributions to illite peak width can be determined independently from measurements of the 001 peak width at half-height and the Srodon intensity ratio. This method yields more information about changes undergone by illite during metamorphism than application of the Kubler index method alone. -Authors

  7. NH AND Mg INDEX TRENDS IN ELLIPTICAL GALAXIES

    SciTech Connect

    Serven, Jedidiah; Worthey, Guy; Toloba, Elisa; Sanchez-Blazquez, Patricia

    2011-06-15

    We examine the spectrum in the vicinity of the NH3360 index of Davidge and Clark, which was defined to measure the NH absorption around 3360 A and shows almost no trend with velocity dispersion, unlike other N-sensitive indices, which show a strong trend. Computing the effect of individual elements on the integrated spectrum with synthetic stellar population integrated spectra, we find that, while being well correlated with nitrogen abundance, NH3360 is almost equally well anti-correlated with Mg abundance. This prompts the definition of two new indices, Mg3334, which is mostly sensitive to magnesium, and NH3375, which is mostly sensitive to nitrogen. Rather surprisingly, we find that the new NH3375 index shows a trend versus optical absorption feature indices that is as shallow as the NH3360 index. We hypothesize that the lack of a strong index trend in these near-UV indices is due to the presence of an old metal-poor component of the galactic population. Comparison of observed index trends and those predicted by models shows that a modest fraction of an old, metal-poor stellar population could easily account for the observed flat trend in these near-UV indices while still allowing substantial N abundance increase in the larger galaxies.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Indexes of severity: conceptual development.

    PubMed Central

    Krischer, J P

    1979-01-01

    A discussion of severity index development is presented in relation to conceptual issues in index definition, analytic issues in index formulation and validation issues in index application. The CHOP index is discussed along with six severity indexes described in an earlier paper dealing with underlying concepts to illustrate the material presented. Replies are provided to specific questions raised in an accompanying paper discussing the Injury Severity Score. This conceptual material is presented to provide a foundation for severity index development, to suggest criteria to be used in their formulation and testing, and to identify analyses that can lead to the successful selection and application of an index for a defined purpose. PMID:468553

  16. A landscape analysis of cougar distribution and abundance in Montana, USA.

    PubMed

    Riley, S J; Malecki, R A

    2001-09-01

    Recent growth in the distribution and abundance of cougars (Puma concolor) throughout western North America has created opportunities, challenges, and problems for wildlife managers and raises questions about what factors affect cougar populations. We present an analysis of factors thought to affect cougar distribution and abundance across the broad geographical scales on which most population management decisions are made. Our objectives were to: (1) identify and evaluate landscape parameters that can be used to predict the capability of habitats to support cougars, and (2) evaluate factors that may account for the recent expansion in cougar numbers. Habitat values based on terrain ruggedness and forested cover explained 73% of the variation in a cougar abundance index. Indices of cougar abundance also were spatially and temporally correlated with ungulate abundance. An increase in the number and total biomass of ungulate prey species is hypothesized to account for recent increases in cougars. Cougar populations in Montana are coping with land development by humans when other components of habitat and prey populations are sufficient. Our analysis provides a better understanding of what may have influenced recent growth in cougar distribution and abundance in Montana and, when combined with insights about stakeholder acceptance capacity, offers a basis for cougar management at broad scales. Long-term conservation of cougars necessitates a better understanding of ecosystem functions that affect prey distribution and abundance, more accurate estimates of cougar populations, and management abilities to integrate these components with human values.

  17. A Sociodemographic Risk Index

    ERIC Educational Resources Information Center

    Moore, Kristin Anderson; Vandivere, Sharon; Redd, Zakia

    2006-01-01

    In this paper, we conceptualize and develop an index of sociodemographic risk that we hypothesize will be an improvement over the standard poverty measure as a measure of risk for children's development. The poverty line is widely used in government statistics and in research but is also widely acknowledged to have multiple shortcomings. Using…

  18. Space Photography 1977 Index

    NASA Technical Reports Server (NTRS)

    1976-01-01

    An index is provided to representative photographs and transparencies available from NASA. Subjects include spacecraft, astronauts, lunar surface, planets and outer space phenomena, earth observations, and aviation. High altitude aircraft infrared photographs are included along with artists' conceptions of space shuttle and space colonies.

  19. Nitrate Leaching Index

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Nitrate Leaching Index is a rapid assessment tool that evaluates nitrate (NO3) leaching potential based on basic soil and climate information. It is the basis for many nutrient management planning efforts, but it has considerable limitations because of : 1) an oversimplification of the processes...

  20. Graded-index magnonics

    NASA Astrophysics Data System (ADS)

    Davies, C. S.; Kruglyak, V. V.

    2015-10-01

    The wave solutions of the Landau-Lifshitz equation (spin waves) are characterized by some of the most complex and peculiar dispersion relations among all waves. For example, the spin-wave ("magnonic") dispersion can range from the parabolic law (typical for a quantum-mechanical electron) at short wavelengths to the nonanalytical linear type (typical for light and acoustic phonons) at long wavelengths. Moreover, the long-wavelength magnonic dispersion has a gap and is inherently anisotropic, being naturally negative for a range of relative orientations between the effective field and the spin-wave wave vector. Nonuniformities in the effective field and magnetization configurations enable the guiding and steering of spin waves in a deliberate manner and therefore represent landscapes of graded refractive index (graded magnonic index). By analogy to the fields of graded-index photonics and transformation optics, the studies of spin waves in graded magnonic landscapes can be united under the umbrella of the graded-index magnonics theme and are reviewed here with focus on the challenges and opportunities ahead of this exciting research direction.

  1. The Vocational Commitment Index

    ERIC Educational Resources Information Center

    Weis, Susan F.; Hubbard, Constance F.

    1973-01-01

    The Index is the result of an effort made to examine all components of vocational commitment and to translate this information into an instrument which could be used to assess the relationship of an individual to a vocation.. The predictive ability of the 74-item device requires further research. (Author/AG)

  2. Drug Impact Index.

    ERIC Educational Resources Information Center

    Western Center for Drug-Free Schools and Communities.

    The Drug Impact Index provides a set of indicators designed to determine the extent of the local drug problem in a community. Each indicator includes a technical note on the data sources, a graph showing comparative statistics on that indicator for the Portland area and for the State of Oregon, and brief remarks on the implications of the data.…

  3. The COPD Helplessness Index

    PubMed Central

    Katz, Patricia P.; Yelin, Edward H.; Iribarren, Carlos; Knight, Sara J.; Blanc, Paul D.; Eisner, Mark D.

    2010-01-01

    Background: Psychologic factors affect how patients with COPD respond to attempts to improve their self-management skills. Learned helplessness may be one such factor, but there is no validated measure of helplessness in COPD. Methods: We administered a new COPD Helplessness Index (CHI) to 1,202 patients with COPD. Concurrent validity was assessed through association of the CHI with established psychosocial measures and COPD severity. The association of helplessness with incident COPD exacerbations was then examined by following subjects over a median 2.1 years, defining COPD exacerbations as COPD-related hospitalizations or ED visits. Results: The CHI demonstrated internal consistency (Cronbach α = 0.75); factor analysis was consistent with the CHI representing a single construct. Greater CHI-measured helplessness correlated with greater COPD severity assessed by the BODE (Body-mass, Obstruction, Dyspnea, Exercise) Index (r = 0.34; P < .001). Higher CHI scores were associated with worse generic (Short Form-12, Physical Component Summary Score) and respiratory-specific (Airways Questionnaire 20) health-related quality of life, greater depressive symptoms, and higher anxiety (all P < .001). Controlling for sociodemographics and smoking status, helplessness was prospectively associated with incident COPD exacerbations (hazard ratio = 1.31; P < .001). After also controlling for the BODE Index, helplessness remained predictive of COPD exacerbations among subjects with BODE Index ≤ median (hazard ratio = 1.35; P = .01), but not among subjects with higher BODE Index values (hazard ratio = 0.93; P = .34). Conclusions: The CHI is an internally consistent and valid measure, concurrently associated with health status and predictively associated with COPD exacerbations. The CHI may prove a useful tool in analyzing differential clinical responses mediated by patient-centered attributes. PMID:19837823

  4. Optimal sampling design for estimating spatial distribution and abundance of a freshwater mussel population

    USGS Publications Warehouse

    Pooler, P.S.; Smith, D.R.

    2005-01-01

    We compared the ability of simple random sampling (SRS) and a variety of systematic sampling (SYS) designs to estimate abundance, quantify spatial clustering, and predict spatial distribution of freshwater mussels. Sampling simulations were conducted using data obtained from a census of freshwater mussels in a 40 X 33 m section of the Cacapon River near Capon Bridge, West Virginia, and from a simulated spatially random population generated to have the same abundance as the real population. Sampling units that were 0.25 m 2 gave more accurate and precise abundance estimates and generally better spatial predictions than 1-m2 sampling units. Systematic sampling with ???2 random starts was more efficient than SRS. Estimates of abundance based on SYS were more accurate when the distance between sampling units across the stream was less than or equal to the distance between sampling units along the stream. Three measures for quantifying spatial clustering were examined: Hopkins Statistic, the Clumping Index, and Morisita's Index. Morisita's Index was the most reliable, and the Hopkins Statistic was prone to false rejection of complete spatial randomness. SYS designs with units spaced equally across and up stream provided the most accurate predictions when estimating the spatial distribution by kriging. Our research indicates that SYS designs with sampling units equally spaced both across and along the stream would be appropriate for sampling freshwater mussels even if no information about the true underlying spatial distribution of the population were available to guide the design choice. ?? 2005 by The North American Benthological Society.

  5. 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.

  6. 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

  7. [Mammals' camera-trapping in Sierra Nanchititla, Mexico: relative abundance and activity patterns].

    PubMed

    Monroy-Vilchis, Octavio; Zarco-González, Martha M; Rodríguez-Soto, Clarita; Soria-Díaz, Leroy; Urios, Vicente

    2011-03-01

    Species conservation and their management depend on the availability of their population behavior and changes in time. This way, population studies include aspects such as species abundance and activity pattern, among others, with the advantage that nowadays new technologies can be applied, in addition to common methods. In this study, we used camera-traps to obtain the index of relative abundance and to establish activity pattern of medium and large mammals in Sierra Nanchititla, Mexico. The study was conducted from December 2003 to May 2006, with a total sampling effort of 4 305 trap-days. We obtained 897 photographs of 19 different species. Nasua narica, Sylvilagus floridanus and Urocyon cinereoargenteus were the most abundant, in agreement with the relative abundance index (RAI, number of independent records/100 trap-days), and according to previous studies with indirect methods in the area. The activity patterns of the species showed that 67% of them are nocturnal, except Odocoileus virginianus, Nasua narica and others. Some species showed differences with previously reported patterns, which are related with seasonality, resources availability, organism sex, principally. The applied method contributed with reliable data about relative abundance and activity patterns.

  8. Relative abundance of mesopredators and size of oak patches in the cross-timbers ecoregion

    USGS Publications Warehouse

    Disney, M.R.; Hellgren, E.C.; Davis, C.A.; Leslie, David M.; Engle, David M.

    2008-01-01

    Mesopredators (e.g., raccoon Procyon lotor, Virginia opossum Didelphis virginiana, striped skunk Mephitis mephitis) have received considerable attention because of links to population declines in birds via increased nest predation, especially in landscapes fragmented by anthropogenic forces. Relationships of abundance of mesopredators to size of habitat patches have received less attention than relationships to other metrics of fragmentation, particularly edge characteristics. We tested the hypothesis that relative abundance of mesopredators (e.g., raccoons and Virginia opossums) was related negatively to size of forest patch. We delineated 15 patches of oak (Quercus) forest ranging from 0.2 to 55.3 ha within a grassland-woodland mosaic in the cross-timbers ecoregion of Oklahoma. Scent stations and live traps within these patches were used to index relative abundance of mesopredators in summers 2003 and 2004. Both indices of relative abundance were related weakly and negatively to area of forest patch. However, rate of capture and visitation to scent station were not correlated consistently throughout the study. Our results suggested that the two methods to index abundance provided separate information on functional and numerical responses to size of patch. Our evidence that mesopredators within the cross timbers were more likely to be in smaller patches of oak forest may have implications to success of avian nesting in these patches.

  9. Fiber optic refractive index monitor

    SciTech Connect

    Weiss, Jonathan David

    2002-01-01

    A sensor for measuring the change in refractive index of a liquid uses the lowest critical angle of a normal fiber optic to achieve sensitivity when the index of the liquid is significantly less than the index of the fiber core. Another embodiment uses a liquid filled core to ensure that its index is approximately the same as the liquid being measured.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Variable Lifting Index (VLI)

    PubMed Central

    Waters, Thomas; Occhipinti, Enrico; Colombini, Daniela; Alvarez-Casado, Enrique; Fox, Robert

    2015-01-01

    Objective: We seek to develop a new approach for analyzing the physical demands of highly variable lifting tasks through an adaptation of the Revised NIOSH (National Institute for Occupational Safety and Health) Lifting Equation (RNLE) into a Variable Lifting Index (VLI). Background: There are many jobs that contain individual lifts that vary from lift to lift due to the task requirements. The NIOSH Lifting Equation is not suitable in its present form to analyze variable lifting tasks. Method: In extending the prior work on the VLI, two procedures are presented to allow users to analyze variable lifting tasks. One approach involves the sampling of lifting tasks performed by a worker over a shift and the calculation of the Frequency Independent Lift Index (FILI) for each sampled lift and the aggregation of the FILI values into six categories. The Composite Lift Index (CLI) equation is used with lifting index (LI) category frequency data to calculate the VLI. The second approach employs a detailed systematic collection of lifting task data from production and/or organizational sources. The data are organized into simplified task parameter categories and further aggregated into six FILI categories, which also use the CLI equation to calculate the VLI. Results: The two procedures will allow practitioners to systematically employ the VLI method to a variety of work situations where highly variable lifting tasks are performed. Conclusions: The scientific basis for the VLI procedure is similar to that for the CLI originally presented by NIOSH; however, the VLI method remains to be validated. Application: The VLI method allows an analyst to assess highly variable manual lifting jobs in which the task characteristics vary from lift to lift during a shift. PMID:26646300

  1. Potential vorticity index

    NASA Technical Reports Server (NTRS)

    Barcilon, Albert; Weng, Hengyi

    1991-01-01

    Based on the European Center For Medium Range Weather Forecasting (ECMWF) First Global Atmospheric Research Program Global Experiment (FGGE) IIIb data set in the 1978 to 1979 winter, a potential vorticity (PV) index was defined as a measure of the zonally averaged, mid-latitude PV gradient on the 300 K isentropic surface in the Northern Hemisphere. The evolution of that index and its relation to teleconnection patterns of 500 mb geopotential height anomaly are studied. The results of the temporal and spatial variation of blocking and cyclogenesis in the 1978 to 1979 winter and its relation to global and local PV gradients were obtained. Complex empirical orthogonal function (EOF) analyses were performed, using the same FGGE data set for the 1978 to 1979 winter, for a representative high latitude band and mid latitude band geopotential height anomalies at 500 mb, phi sub h, phi sub m, and PV gradient at 300 K, delta(Q), at each longitude for the three month period. The focus of current research is the following: (1) to perform Fourier analyses for the first three EOF's of phi sub h, phi sub m, and delta(Q) at given latitude bands, and to find the dominant wavenumbers and frequencies which are responsible for these EOF's; (2) to compare the results from EOF and Fourier analyses which will be used to explore the relations of blocking and cyclogensis with local and global PV gradients; and (3) to study the time dependence of the local PV gradients and relate it to the PV index vacillation cycles observed in the PV index cycle.

  2. Using counts to simultaneously estimate abundance and detection probabilities in a salamander community

    USGS Publications Warehouse

    Dodd, C.K.; Dorazio, R.M.

    2004-01-01

    A critical variable in both ecological and conservation field studies is determining how many individuals of a species are present within a defined sampling area. Labor intensive techniques such as capture-mark-recapture and removal sampling may provide estimates of abundance, but there are many logistical constraints to their widespread application. Many studies on terrestrial and aquatic salamanders use counts as an index of abundance, assuming that detection remains constant while sampling. If this constancy is violated, determination of detection probabilities is critical to the accurate estimation of abundance. Recently, a model was developed that provides a statistical approach that allows abundance and detection to be estimated simultaneously from spatially and temporally replicated counts. We adapted this model to estimate these parameters for salamanders sampled over a six vear period in area-constrained plots in Great Smoky Mountains National Park. Estimates of salamander abundance varied among years, but annual changes in abundance did not vary uniformly among species. Except for one species, abundance estimates were not correlated with site covariates (elevation/soil and water pH, conductivity, air and water temperature). The uncertainty in the estimates was so large as to make correlations ineffectual in predicting which covariates might influence abundance. Detection probabilities also varied among species and sometimes among years for the six species examined. We found such a high degree of variation in our counts and in estimates of detection among species, sites, and years as to cast doubt upon the appropriateness of using count data to monitor population trends using a small number of area-constrained survey plots. Still, the model provided reasonable estimates of abundance that could make it useful in estimating population size from count surveys.

  3. New weather index

    NASA Astrophysics Data System (ADS)

    Scientists at the National Oceanic and Atmospheric Administration (NOAA) and the University of Delaware have refined the wind-chill factor, a common measurement of weather discomfort, into a new misery register called the weather stress index. In addition to the mix of temperature and wind speed data used to calculate wind chill, the recipe for the index adds two new ingredients—humidity and a dash of benchmark statistics—to estimate human reaction to weather conditions. NOAA says that the weather stress index estimates human reaction to weather conditions and that the reaction depends on variations from the ‘normal’ conditions in the locality involved.Discomfort criteria for New Orleans, La., and Bismarck, N.D., for example, differ drastically. According to NOAA, when it's the middle of winter and it's -10°C with a relative humidity of 80% and 24 km/h winds, persons in New Orleans would be highly stressed while those in Bismarck wouldn't bat an eye.

  4. Index of cyber integrity

    NASA Astrophysics Data System (ADS)

    Anderson, Gustave

    2014-05-01

    Unfortunately, there is no metric, nor set of metrics, that are both general enough to encompass all possible types of applications yet specific enough to capture the application and attack specific details. As a result we are left with ad-hoc methods for generating evaluations of the security of our systems. Current state of the art methods for evaluating the security of systems include penetration testing and cyber evaluation tests. For these evaluations, security professionals simulate an attack from malicious outsiders and malicious insiders. These evaluations are very productive and are able to discover potential vulnerabilities resulting from improper system configuration, hardware and software flaws, or operational weaknesses. We therefore propose the index of cyber integrity (ICI), which is modeled after the index of biological integrity (IBI) to provide a holistic measure of the health of a system under test in a cyber-environment. The ICI provides a broad base measure through a collection of application and system specific metrics. In this paper, following the example of the IBI, we demonstrate how a multi-metric index may be used as a holistic measure of the health of a system under test in a cyber-environment.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Indexing Overlap and Consistency between the "Avery Index to Architectural Periodicals" and the "Architectural Periodicals Index."

    ERIC Educational Resources Information Center

    Giral, Angela; Taylor, Arlene G.

    1993-01-01

    Examines the overlap of article coverage and the consistency of indexing between the "Avery Index to Architectural Periodicals" and the "Architectural Periodicals Index." The historical backgrounds of the two indexes are described, possibilities for collaboration between them are considered, and implications for users are…

  10. The photospheric abundances of active binaries. II. Atmospheric parameters and abundance patterns for 6 single-lined RS CVn systems

    NASA Astrophysics Data System (ADS)

    Morel, T.; Micela, G.; Favata, F.; Katz, D.; Pillitteri, I.

    2003-12-01

    Photospheric parameters and abundances are presented for a sample of single-lined chromospherically active binaries from a differential LTE analysis of high-resolution spectra. Abundances have been derived for 13 chemical species, including several key elements such as Li, Mg, and Ca. Two methods have been used. The effective temperatures, surface gravities and microturbulent velocities were first derived from a fully self-consistent analysis of the spectra, whereby the temperature is determined from the excitation equilibrium of the Fe I lines. The second approach relies on temperatures derived from the (B-V) colour index. These two methods give broadly consistent results for the stars in our sample, suggesting that the neutral iron lines are formed under conditions close to LTE. We discuss the reliability in the context of chromospherically active stars of various colour indices used as temperature indicators, and conclude that the (V-R) and (V-I) colours are likely to be significantly affected by activity processes. Irrespective of the method used, our results indicate that the X-ray active binaries studied are not as metal poor as previously claimed, but are at most mildly iron-depleted relative to the Sun (-0.41protect <~ [Fe/H]protect la +0.11). A significant overabundance of several chemical species is observed (e.g., the alpha -synthezised elements). These abundance patterns are discussed in relation to stellar activity. Based on observations collected at ESO (La Silla, Chile). Table A.1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/495

  11. Calibrating abundance indices with population size estimators of red back salamanders (Plethodon cinereus) in a New England forest

    PubMed Central

    Ellison, Aaron M.; Jackson, Scott

    2015-01-01

    Herpetologists and conservation biologists frequently use convenient and cost-effective, but less accurate, abundance indices (e.g., number of individuals collected under artificial cover boards or during natural objects surveys) in lieu of more accurate, but costly and destructive, population size estimators to detect and monitor size, state, and trends of amphibian populations. Although there are advantages and disadvantages to each approach, reliable use of abundance indices requires that they be calibrated with accurate population estimators. Such calibrations, however, are rare. The red back salamander, Plethodon cinereus, is an ecologically useful indicator species of forest dynamics, and accurate calibration of indices of salamander abundance could increase the reliability of abundance indices used in monitoring programs. We calibrated abundance indices derived from surveys of P. cinereus under artificial cover boards or natural objects with a more accurate estimator of their population size in a New England forest. Average densities/m2 and capture probabilities of P. cinereus under natural objects or cover boards in independent, replicate sites at the Harvard Forest (Petersham, Massachusetts, USA) were similar in stands dominated by Tsuga canadensis (eastern hemlock) and deciduous hardwood species (predominantly Quercus rubra [red oak] and Acer rubrum [red maple]). The abundance index based on salamanders surveyed under natural objects was significantly associated with density estimates of P. cinereus derived from depletion (removal) surveys, but underestimated true density by 50%. In contrast, the abundance index based on cover-board surveys overestimated true density by a factor of 8 and the association between the cover-board index and the density estimates was not statistically significant. We conclude that when calibrated and used appropriately, some abundance indices may provide cost-effective and reliable measures of P. cinereus abundance that could

  12. Calibrating abundance indices with population size estimators of red back salamanders (Plethodon cinereus) in a New England forest.

    PubMed

    Siddig, Ahmed A; Ellison, Aaron M; Jackson, Scott

    2015-01-01

    Herpetologists and conservation biologists frequently use convenient and cost-effective, but less accurate, abundance indices (e.g., number of individuals collected under artificial cover boards or during natural objects surveys) in lieu of more accurate, but costly and destructive, population size estimators to detect and monitor size, state, and trends of amphibian populations. Although there are advantages and disadvantages to each approach, reliable use of abundance indices requires that they be calibrated with accurate population estimators. Such calibrations, however, are rare. The red back salamander, Plethodon cinereus, is an ecologically useful indicator species of forest dynamics, and accurate calibration of indices of salamander abundance could increase the reliability of abundance indices used in monitoring programs. We calibrated abundance indices derived from surveys of P. cinereus under artificial cover boards or natural objects with a more accurate estimator of their population size in a New England forest. Average densities/m(2) and capture probabilities of P. cinereus under natural objects or cover boards in independent, replicate sites at the Harvard Forest (Petersham, Massachusetts, USA) were similar in stands dominated by Tsuga canadensis (eastern hemlock) and deciduous hardwood species (predominantly Quercus rubra [red oak] and Acer rubrum [red maple]). The abundance index based on salamanders surveyed under natural objects was significantly associated with density estimates of P. cinereus derived from depletion (removal) surveys, but underestimated true density by 50%. In contrast, the abundance index based on cover-board surveys overestimated true density by a factor of 8 and the association between the cover-board index and the density estimates was not statistically significant. We conclude that when calibrated and used appropriately, some abundance indices may provide cost-effective and reliable measures of P. cinereus abundance that

  13. The Carina Project. VIII. The α-element abundances

    NASA Astrophysics Data System (ADS)

    Fabrizio, M.; Nonino, M.; Bono, G.; Primas, F.; Thévenin, F.; Stetson, P. B.; Cassisi, S.; Buonanno, R.; Coppola, G.; da Silva, R. O.; Dall'Ora, M.; Ferraro, I.; Genovali, K.; Gilmozzi, R.; Iannicola, G.; Marconi, M.; Monelli, M.; Romaniello, M.; Walker, A. R.

    2015-08-01

    We have performed a new abundance analysis of Carina red giant (RG) stars from spectroscopic data collected with UVES (high spectral resolution) and FLAMES/GIRAFFE (high and medium resolution) at ESO/VLT. The former sample includes 44 RGs, while the latter consists of 65 (high-resolution) and ~800 (medium-resolution) RGs, covering a significant fraction of the galaxy's RG branch, and red clump stars. To improve the abundance analysis at the faint magnitude limit, the FLAMES/GIRAFFE data were divided into ten surface gravity and effective temperature bins. The spectra of the stars belonging to the same gravity and temperature bin were stacked. This approach allowed us to increase the signal-to-noise ratio in the faint magnitude limit (V≥ 20.5 mag) by at least a factor of five. We took advantage of the new photometry index cU,B,I introduced recently as an age and probably a metallicity indicator to split stars along the red giant branch. These two stellar populations display distinct [Fe/H] and [Mg/H] distributions: their mean iron abundances are -2.15 ± 0.06 dex (σ = 0.28), and -1.75 ± 0.03 dex (σ = 0.21), respectively. The two iron distributions differ at the 75% level. This supports preliminary results. Moreover, we found that the old and intermediate-age stellar populations have mean [Mg/H] abundances of -1.91 ± 0.05 dex (σ = 0.22) and -1.35 ± 0.03 dex (σ = 0.22); these differ at the 83% level. Carina's α-element abundances agree, within 1σ, with similar abundances for field halo stars and for cluster (Galactic and Magellanic) stars. The same outcome applies to nearby dwarf spheroidals and ultra-faint dwarf galaxies in the iron range covered by Carina stars. Finally, we found evidence of a clear correlation between Na and O abundances, thus suggesting that Carina's chemical enrichment history is quite different from that in the globular clusters. Based on spectra retrieved from the ESO/ST-ECF Science Archive Facility and collected either with UVES at

  14. Relating trophic resources to community structure: a predictive index of food availability

    PubMed Central

    Edgar, Graham J.

    2017-01-01

    The abundance and the distribution of trophic resources available for consumers influence the productivity and the diversity of natural communities. Nevertheless, assessment of the actual abundance of food items available for individual trophic groups has been constrained by differences in methods and metrics used by various authors. Here we develop an index of food abundance, the framework of which can be adapted for different ecosystems. The relative available food index (RAFI) is computed by considering standard resource conditions of a habitat and the influence of various generalized anthropogenic and natural factors. RAFI was developed using published literature on food abundance and validated by comparison of predictions versus observed trophic resources across various marine sites. RAFI tables here proposed can be applied to a range of marine ecosystems for predictions of the potential abundance of food available for each trophic group, hence permitting exploration of ecological theories by focusing on the deviation from the observed to the expected. PMID:28386417

  15. 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...

  16. 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...

  17. 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.

  18. [Microbial community abundance and diversity in typical karst ecosystem to indicate soil carbon cycle].

    PubMed

    Jin, Zhen-Jiang; Tang, Hua-Feng; Li, Min; Huang, Bing-Fu; Li, Qiang; Zhang, Jia-Yu; Li, Gui-Wen

    2014-11-01

    The soil microbial characteristics were detected to clarify their indications in organic carbon cycle in karst system. Soil samples from three karst types (saddle, depression and slop) at 0-10 cm, 10-20 cm and 20-30 cm layers were collected in the Yaji Karst Experimental Site, a typical karst ecosystem. The microbial diversity and abundance were assayed using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and fluorescence quantitative PCR. The data showed that the highest abundance of 16S rRNA and 18S rRNA were in depression with 1.32 x 10(11) copies x g(-1) and in saddle with 1.12 x 10(10) copies x g(-1), respectively. The abundance of 16S rRNA in saddle and depression decreased from top to bottom, while that of 18S rRNA in three karst forms decreased, which showed that the abundance changed consistently with soil organic carbon (SOC). The 3 diversity indices of 16S rRNA and 6 diversity indices of 18S rRNA increased from top to bottom in soil profiles of three karst forms. These results showed that microbial diversity changed conversely with the abundance and SOC in soil profile. It can be concluded that the abundance was more important than the diversity index for soil carbon cycle in karst system.

  19. 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.

  20. 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…

  1. 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.

  2. 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.

  3. 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.

  4. 29. TRACK LAYOUT, INDEX TO DRAWINGS AND INDEX TO MATERIALS, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. TRACK LAYOUT, INDEX TO DRAWINGS AND INDEX TO MATERIALS, REED & STEM ARCHITECTS, ST. PAUL, NEW YORK, 1909 (Burlington Northern Collection, Seattle, Washington) - Union Passenger Station Concourse, 1713 Pacific Avenue, Tacoma, Pierce County, WA

  5. Mosquito (Diptera: Culicidae) and predator abundance in irrigated and rain-fed rice fields in north Sulawesi, Indonesia.

    PubMed

    Mogi, M; Memah, V; Miyagi, I; Toma, T; Sembel, D T

    1995-05-01

    Immature mosquito species composition and abundance were studied in irrigated and rain-fed rice fields of North Sulawesi, Indonesia. Irrigated rice fields were characterized by the prevalence of aquatic macrophytes and cyprinodont larvivorous fish, Aplocheilus panchax (Hamilton), but abundance per dip of most aquatic insect predators was lower than that in rain-fed rice fields. Anopheles peditaeniatus (Leicester), Culex vishnui Theobald, and Culex tritaeniorhynchus Giles, were dominant in both irrigated and rain-fed fields, but the abundance of the Culex species was lower in irrigated fields. The effect of irrigation system introduction on regional mosquito abundance cannot be evaluated by the enlarged surface water area alone. Changes in habitat quality, expressed as the abundance per dip (index of density per unit water area), also need to be considered.

  6. 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.

  7. 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.

  8. Body Mass Index

    PubMed Central

    Nuttall, Frank Q.

    2015-01-01

    The body mass index (BMI) is the metric currently in use for defining anthropometric height/weight characteristics in adults and for classifying (categorizing) them into groups. The common interpretation is that it represents an index of an individual’s fatness. It also is widely used as a risk factor for the development of or the prevalence of several health issues. In addition, it is widely used in determining public health policies.The BMI has been useful in population-based studies by virtue of its wide acceptance in defining specific categories of body mass as a health issue. However, it is increasingly clear that BMI is a rather poor indicator of percent of body fat. Importantly, the BMI also does not capture information on the mass of fat in different body sites. The latter is related not only to untoward health issues but to social issues as well. Lastly, current evidence indicates there is a wide range of BMIs over which mortality risk is modest, and this is age related. All of these issues are discussed in this brief review. PMID:27340299

  9. State-of-the-Art Metal Abundances For Field RR Lyrae Variables

    NASA Astrophysics Data System (ADS)

    Carretta, E.; Clementini, G.; Merighi, R.; Gratton, R. G.; Mould, J. R.; McCarthy, J. K.

    1996-04-01

    We present abundance analysis for 10 field ab-type RR Lyraes, using high S/N (>200), moderately high resolution ( ~ 18000) CCD spectra to obtain accurate metallicities. A new temperature scale was determined and non-LTE effects were fully taken into account. The derived metal abundances of the program stars span the range -2.50 < [Fe/H] < +0.17. We used our new [Fe/H] abundances, as well as values from Butler and coworkers (corrected to our system), to obtain a revised calibration of the Delta S index (Preston 1959): $[Fe/H] = -0.194(+/- 0.011)Delta S - 0.08 (+/- 0.18) $ Our new metallicity scale is then stretched on both low and high metallicity ends with respect to Butler's (1975) calibration.

  10. 2013 Traffic Safety Culture Index

    MedlinePlus

    ... death in the United States. 2013 Traffic Safety Culture Index January 2014 607 14th Street, NW, Suite ... org | 202-638-5944 Title 2013 Traffic Safety Culture Index (January 2014) About the Sponsor AAA Foundation ...

  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. Seasonal Abundance, Spatial Distribution, Spawning and Growth of Astropecten irregularis (Echinodermata: Asteroidea)

    NASA Astrophysics Data System (ADS)

    Freeman, S. M.; Richardson, C. A.; Seed, R.

    2001-07-01

    Seasonal trends in the abundance, spatial distribution, spawning and growth of a population of Astropecten irregularis inhabiting the coastal waters of North Wales are described. Population densities of A. irregularis varied seasonally with starfish attaining their maximum and minimum abundances in summer and winter respectively. Changes in their spatial distribution strongly suggests that A. irregularis migrates offshore into deeper waters during the winter months probably to avoid strong onshore wave surges. High population densities of starfish which occur during the summer months may be associated with spawning aggregations or the availability of suitable prey species; a smaller peak in starfish abundance occurred during autumn 1997 coinciding with the settlement of the bivalve Spisula subtruncata and the cumacean Diastylis rugosa , prey species which are readily consumed by A. irregularis. Astropecten irregularis spawned during late spring-early summer, but thereafter the gonad somatic index remained at a low level until late autumn; the index increased throughout winter and starfish attained peak reproductive condition by late spring. Small starfish (arm length <24 mm), showed little evidence of reproductive development. Limited recruitment of A. irregularis (<8 mm) occurred during October-November 1996, and the integration of this small cohort into the main population occurred within one year. Locomotory activity and burrowing depth of starfish maintained in laboratory aquaria correlated with changes in seawater temperature; activity was largely inhibited and burrowing depth significantly increased at temperatures <8 °C. Seawater temperature is probably an important factor regulating the abundance and distribution of A. irregularis in coastal waters.

  14. 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.

  15. 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.

  16. 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.

  17. Protein profile of exhaled breath condensate determined by high resolution mass spectrometry.

    PubMed

    Muccilli, Vera; Saletti, Rosaria; Cunsolo, Vincenzo; Ho, Jenny; Gili, Elisa; Conte, Enrico; Sichili, Stefania; Vancheri, Carlo; Foti, Salvatore

    2015-02-01

    A method based on liquid chromatography/high resolution tandem mass spectrometry coupled with electrophoretic separation, for determination and relative quantification of the protein composition of exhaled breath condensate (EBC), was developed. Application of the procedure to a sample of EBC, pooled from nine healthy subjects, resulted in the identification of 167 unique gene products, 113 of which not previously reported in EBC samples. The abundance of the protein identified was estimated by means of the exponentially modified protein abundance index protocol (emPAI). Cytokeratins were by far the most abundant proteins in EBC samples. Many of the identified proteins were associated with multiple cellular location with cytoplasm constituting the largest group. Cytosol, nucleus, membrane, cytoskeleton and extracellular were other abundantly represented locations. No amylase was detected, suggesting the absence of saliva protein contamination. The profile obtained represents the most comprehensive protein characterization of EBC so far reported and demonstrates that this approach provides a powerful tool for investigating the protein profile of EBC samples. Compared with analogous investigations, this study also shows that the protein profile of EBC is strongly affected by the sampling method adopted.

  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. Global Enhanced Vegetation Index

    NASA Technical Reports Server (NTRS)

    2002-01-01

    By carefully measuring the wavelengths and intensity of visible and near-infrared light reflected by the land surface back up into space, the Moderate-resolution Imaging Spectroradiometer (MODIS) Team can quantify the concentrations of green leaf vegetation around the world. The above MODIS Enhanced Vegetation Index (EVI) map shows the density of plant growth over the entire globe. Very low values of EVI (white and brown areas) correspond to barren areas of rock, sand, or snow. Moderate values (light greens) represent shrub and grassland, while high values indicate temperate and tropical rainforests (dark greens). The MODIS EVI gives scientists a new tool for monitoring major fluctuations in vegetation and understanding how they affect, and are affected by, regional climate trends. For more information, read NASA Unveils Spectacular Suite of New Global Data Products from MODIS. Image courtesy MODIS Land Group/Vegetation Indices, Alfredo Huete, Principal Investigator, and Kamel Didan, University of Arizona

  4. [Ankle brachial index measurement].

    PubMed

    Rucigaj, Tanja Planinsek

    2014-10-01

    Ultrasound examinations are noninvasive diagnostic methods which, along with appropriate history and clinical examination, provide basic information on the etiology and spread of the disease, as well as on treatment options required in patients with chronic venous insufficiency and arterial flow impairment. Doppler flow meter offers useful data on venous blood return, primarily in great veins, while both deep and superficial veins as well as arteries can be visualized and data on venous and arterial hemodynamics obtained by duplex ultrasonography. In addition, Doppler flow meter provides data on the peripheral arterial system action through ankle brachial index measurement, which will guide the choice of compression therapy when deciding on the treatment of peripheral arterial disease and mixed arteriovenous leg ulcers. However, diagnosis of arterial insufficiency requires additional examinations.

  5. A Windshear Hazard Index

    NASA Technical Reports Server (NTRS)

    Proctor, Fred H.; Hinton, David A.; Bowles, Roland L.

    2000-01-01

    An aircraft exposed to hazardous low-level windshear may suffer a critical loss of airspeed and altitude, thus endangering its ability to remain airborne. In order to characterize this hazard, a nondimensional index was developed based oil aerodynamic principals and understanding of windshear phenomena, 'This paper reviews the development and application of the Bowles F-tactor. which is now used by onboard sensors for the detection of hazardous windshear. It was developed and tested during NASA/I:AA's airborne windshear program and is now required for FAA certification of onboard radar windshear detection systems. Reviewed in this paper are: 1) definition of windshear and description of atmospheric phenomena that may cause hazardous windshear. 2) derivation and discussion of the F-factor. 3) development of the F-factor hazard threshold, 4) its testing during field deployments, and 5) its use in accident reconstructions,

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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].

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. [Aquatic Ecological Index based on freshwater (ICE(RN-MAE)) for the Rio Negro watershed, Colombia].

    PubMed

    Forero, Laura Cristina; Longo, Magnolia; John Jairo, Ramirez; Guillermo, Chalar

    2014-04-01

    Aquatic Ecological Index based on freshwater (ICE(RN-MAE)) for the Rio Negro watershed, Colombia. Available indices to assess the ecological status of rivers in Colombia are mostly based on subjective hypotheses about macroinvertebrate tolerance to pollution, which have important limitations. Here we present the application of a method to establish an index of ecological quality for lotic systems in Colombia. The index, based on macroinvertebrate abundance and physicochemical variables, was developed as an alternative to the BMWP-Col index. The method consists on determining an environmental gradient from correlations between physicochemical variables and abundance. The scores obtained in each sampling point are used in a standardized correlation for a model of weighted averages (WA). In the WA model abundances are also weighted to estimate the optimum and tolerance values of each taxon; using this information we estimated the index of ecological quality based also on macroinvertebrate (ICE(RN-MAE)) abundance in each sampling site. Subsequently, we classified all sites using the index and concentrations of total phosphorus (TP) in a cluster analysis. Using TP and ICE(RN-MAE), mean, maximum, minimum and standard deviation, we defined threshold values corresponding to three categories of ecological status: good, fair and critical.

  3. The glycemic index.

    PubMed

    Wolever, T M

    1990-01-01

    Different starchy foods produce different glycemic responses when fed individually, and there is evidence that this also applies in the context of the mixed meal. Methods of processing, and other factors unrelated to the nutrient composition of foods may also have major effects on the glycemic response. The reason for differences in glycemic response appears to relate to the rate at which the foods are digested and the many factors influencing this. The glycemic index (GI) is a system of classification in which the glycemic responses of foods are indexed against a standard (white bread). This allows the results of different investigators to be pooled. GI values also depend upon a number of nonfood-related variables. The method of calculation of the glycemic response area is most important, but the method of blood sampling and length of time of studies also may have effects. Variability of glycemic responses arises from day-to-day variation in the same subject and variation between different subjects. There is less variability between the GI values of different subjects than there is within the same subject from day to day. Therefore, the mean GI values of foods are independent of the glucose tolerance status of the subjects being tested. Potentially clinically useful starchy foods producing relatively flat glycemic responses have been identified, including legumes, pasta, barley, bulgur, parboiled rice and whole grain breads such as pumpernickel. Specific incorporation of these foods into diets have been associated with reduced blood glucose, insulin, and lipid levels. Low-GI foods may influence amino acid metabolism although the implications of these are unknown. In addition, low GI foods increase colonic fermentation. The physiologic and metabolic implications of this relate to increased bacterial urea utilization, and to the production and absorption of short chain fatty acids in the colon. The application of the GI to therapeutic diets should be in the context

  4. Relative abundance and size of coastal sharks derived from commercial shark longline catch and effort data.

    PubMed

    Carlson, J K; Hale, L F; Morgan, A; Burgess, G

    2012-04-01

    In the north-west Atlantic Ocean, stock assessments conducted for some commercially harvested coastal sharks indicate declines from 64 to 80% with respect to virgin population levels. While the status of commercially important species is available, abundance trend information for other coastal shark species in the north-west Atlantic Ocean are unavailable. Using a generalized linear modelling (GLM) approach, a relative abundance index was derived from 1994 to 2009 using observer data collected in a commercial bottom longline fishery. Trends in abundance and average size were estimated for bull shark Carcharhinus leucas, spinner shark Carcharhinus brevipinna, tiger shark Galeocerdo cuvier and lemon shark Negaprion brevirostris. Increases in relative abundance for all shark species ranged from 14% for C. brevipinna, 12% for C. leucas, 6% for N. brevirostris and 3% for G. cuvier. There was no significant change in the size at capture over the time period considered for all species. While the status of shark populations should not be based exclusively on abundance trend information, but ultimately on stock assessment models, results from this study provide some cause for optimism on the status of these coastal shark species.

  5. Does beach nourishment have long-term effects on intertidal macroinvertebrate species abundance?

    NASA Astrophysics Data System (ADS)

    Leewis, Lies; van Bodegom, Peter M.; Rozema, Jelte; Janssen, Gerard M.

    2012-11-01

    Coastal squeeze is the largest threat for sandy coastal areas. To mitigate seaward threats, erosion and sea level rise, sand nourishment is commonly applied. However, its long-term consequences for macroinvertebrate fauna, critical to most ecosystem services of sandy coasts, are still unknown. Seventeen sandy beaches - nourished and controls - were sampled along a chronosequence to investigate the abundance of four dominant macrofauna species and their relations with nourishment year and relevant coastal environmental variables. Dean's parameter and latitude significantly explained the abundance of the spionid polychaete Scolelepis squamata, Beach Index (BI), sand skewness, beach slope and latitude explained the abundance of the amphipod Haustorius arenarius and Relative Tide Range (RTR), recreation and sand sorting explained the abundance of Bathyporeia sarsi. For Eurydice pulchra, no environmental variable explained its abundance. For H. arenarius, E. pulchra and B. sarsi, there was no relation with nourishment year, indicating that recovery took place within a year after nourishment. Scolelepis squamata initially profited from the nourishment with "over-recolonisation". This confirms its role as an opportunistic species, thereby altering the initial community structure on a beach after nourishment. We conclude that the responses of the four dominant invertebrates studied in the years following beach nourishment are species specific. This shows the importance of knowing the autecology of the sandy beach macroinvertebrate fauna in order to be able to mitigate the effects of beach nourishment and other environmental impacts.

  6. Distribution and abundance of fish larvae in the northern Ionian Sea (Eastern Mediterranean)

    NASA Astrophysics Data System (ADS)

    Granata, Antonia; Cubeta, Annaluce; Minutoli, Roberta; Bergamasco, Alessandro; Guglielmo, Letterio

    2011-09-01

    The purpose of this paper was to study the spatial distribution, abundance and composition of fish larvae in the northern Ionian Sea. Samples were collected to the 600 m depth with an electronic multinet BIONESS during the "INTERREG Italia-Grecia" oceanographic cruise carried out in March 2000 off the Apulian Italian coast. A total of 46 species of teleost early stages were collected, belonging to 38 genera and 22 families. Over 52% of the larvae identified were mesopelagic species, almost 27% were demersal and about 21% pelagic. A total of 307 myctophids, 69 clupeids and 61 gadid post-larvae dominated the community. Benthosema glaciale (mean 6.1 mm SL) was the most abundant species (21.6%), the most frequent in the samples (28.8%), and dominant in the whole study area (mean 1.4 ind/100 m3). Particular attention was given to the horizontal and vertical distribution and abundance of the three dominant post-larval species: Benthosema glaciale, Sprattus sprattus sprattus and Notoscopelus elongatus. The Pearson coefficient ( R = 0.734) showed a high correlation between total zooplankton and fish larval assemblages in terms of spatial distribution abundance values. Regarding the vertical distribution of fish larvae, Sorensen's index ( S = 0.69) showed that fish larvae and total zooplankton abundance peaks co-occurred along the water column.

  7. Abundance trends and status of the Little Colorado River population of humpback chub

    USGS Publications Warehouse

    Coggins, L.G.; Pine, William E.; Walters, C.J.; Van Haverbeke, D. R.; Ward, D.; Johnstone, H.C.

    2006-01-01

    The abundance of the Little Colorado River population of federally listed humpback chub Gila cypha in Grand Canyon has been monitored since the late 1980s by means of catch rate indices and capture-recapture-based abundance estimators. Analyses of data from all sources using various methods are consistent and indicate that the adult population has declined since monitoring began. Intensive tagging led to a high proportion (>80%) of the adult population being marked by the mid-1990s. Analysis of these data using both closed and open abundance estimation models yields results that agree with catch rate indices about the extent of the decline. Survival rates for age-2 and older fish are age dependent but apparently not time dependent. Back-calculation of recruitment using the apparent 1990s population age structure implies periods of higher recruitment in the late 1970s to early 1980s than is now the case. Our analyses indicate that the U.S. Fish and Wildlife Service recovery criterion of stable abundance is not being met for this population. Also, there is a critical need to develop new abundance indexing and tagging methods so that early, reliable, and rapid estimates of humpback chub recruitment can be obtained to evaluate population responses to management actions designed to facilitate the restoration of Colorado River native fish communities. ?? Copyright by the American Fisheries Society 2006.

  8. Applied Parallel Metadata Indexing

    SciTech Connect

    Jacobi, Michael R

    2012-08-01

    The GPFS Archive is parallel archive is a parallel archive used by hundreds of users in the Turquoise collaboration network. It houses 4+ petabytes of data in more than 170 million files. Currently, users must navigate the file system to retrieve their data, requiring them to remember file paths and names. A better solution might allow users to tag data with meaningful labels and searach the archive using standard and user-defined metadata, while maintaining security. last summer, I developed the backend to a tool that adheres to these design goals. The backend works by importing GPFS metadata into a MongoDB cluster, which is then indexed on each attribute. This summer, the author implemented security and developed the user interfae for the search tool. To meet security requirements, each database table is associated with a single user, which only stores records that the user may read, and requires a set of credentials to access. The interface to the search tool is implemented using FUSE (Filesystem in USErspace). FUSE is an intermediate layer that intercepts file system calls and allows the developer to redefine how those calls behave. In the case of this tool, FUSE interfaces with MongoDB to issue queries and populate output. A FUSE implementation is desirable because it allows users to interact with the search tool using commands they are already familiar with. These security and interface additions are essential for a usable product.

  9. 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.

  10. 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

  11. Abundance-weighted phylogenetic diversity measures distinguish microbial community states and are robust to sampling depth.

    PubMed

    McCoy, Connor O; Matsen, Frederick A

    2013-01-01

    In microbial ecology studies, the most commonly used ways of investigating alpha (within-sample) diversity are either to apply non-phylogenetic measures such as Simpson's index to Operational Taxonomic Unit (OTU) groupings, or to use classical phylogenetic diversity (PD), which is not abundance-weighted. Although alpha diversity measures that use abundance information in a phylogenetic framework do exist, they are not widely used within the microbial ecology community. The performance of abundance-weighted phylogenetic diversity measures compared to classical discrete measures has not been explored, and the behavior of these measures under rarefaction (sub-sampling) is not yet clear. In this paper we compare the ability of various alpha diversity measures to distinguish between different community states in the human microbiome for three different datasets. We also present and compare a novel one-parameter family of alpha diversity measures, BWPDθ, that interpolates between classical phylogenetic diversity (PD) and an abundance-weighted extension of PD. Additionally, we examine the sensitivity of these phylogenetic diversity measures to sampling, via computational experiments and by deriving a closed form solution for the expectation of phylogenetic quadratic entropy under re-sampling. On the three datasets, a phylogenetic measure always performed best, and two abundance-weighted phylogenetic diversity measures were the only measures ranking in the top four across all datasets. OTU-based measures, on the other hand, are less effective in distinguishing community types. In addition, abundance-weighted phylogenetic diversity measures are less sensitive to differing sampling intensity than their unweighted counterparts. Based on these results we encourage the use of abundance-weighted phylogenetic diversity measures, especially for cases such as microbial ecology where species delimitation is difficult.

  12. 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.

  13. 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.

  14. 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.

  15. 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).

  16. 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.

  17. Sampling designs matching species biology produce accurate and affordable abundance indices

    PubMed Central

    Farley, Sean; Russell, Gareth J.; Butler, Matthew J.; Selinger, Jeff

    2013-01-01

    raised capture probabilities. The grid design was least biased (−10.5%), but imprecise (CV 21.2%), and used most effort (16,100 trap-nights). The targeted configuration was more biased (−17.3%), but most precise (CV 12.3%), with least effort (7,000 trap-nights). Targeted sampling generated encounter rates four times higher, and capture and recapture probabilities 11% and 60% higher than grid sampling, in a sampling frame 88% smaller. Bears had unequal probability of capture with both sampling designs, partly because some bears never had traps available to sample them. Hence, grid and targeted sampling generated abundance indices, not estimates. Overall, targeted sampling provided the most accurate and affordable design to index abundance. Targeted sampling may offer an alternative method to index the abundance of other species inhabiting expansive and inaccessible landscapes elsewhere, provided their attraction to resource concentrations. PMID:24392290

  18. Nuclear Energy Standards. KWIC index

    SciTech Connect

    Not Available

    1984-01-01

    The KWIC Index is an alphabetical listing that provides rapid identification of NE standards based upon the specific subject areas. This index facilitates identification of a NE standard by major or key words located in the center of the alphabetical index listing. Alphanumerical designations for specific NE standards are shown in the right-hand column. Standards referenced in this listing include those that are active, inactive, or discontinued.

  19. Aeronautical Engineering: 1983 cumulative index

    NASA Technical Reports Server (NTRS)

    1984-01-01

    This bibliography is a cumulative index to the abstracts contained in NASA SP-7037 (158) through NASA SP-7037 (169) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, contract, report number, and accession number indexes.

  20. Hardware Index to Permutation Converter

    DTIC Science & Technology

    2012-05-01

    Hardware Index to Permutation Converter J. T. Butler T. Sasao Department of Electrical and Computer Engineering Department of Computer Science...generates a permutation in response to an index. Since there are n! n-element permutations , the index ranges from 0 to n! − 1. Such a circuit is needed...in the hardware implementation of unique- permutation hash functions to specify how parallel machines interact through a shared memory. Such a circuit

  1. Natural variation in stomatal abundance of Arabidopsis thaliana includes cryptic diversity for different developmental processes

    PubMed Central

    Delgado, Dolores; Alonso-Blanco, Carlos; Fenoll, Carmen; Mena, Montaña

    2011-01-01

    Background and Aims Current understanding of stomatal development in Arabidopsis thaliana is based on mutations producing aberrant, often lethal phenotypes. The aim was to discover if naturally occurring viable phenotypes would be useful for studying stomatal development in a species that enables further molecular analysis. Methods Natural variation in stomatal abundance of A. thaliana was explored in two collections comprising 62 wild accessions by surveying adaxial epidermal cell-type proportion (stomatal index) and density (stomatal and pavement cell density) traits in cotyledons and first leaves. Organ size variation was studied in a subset of accessions. For all traits, maternal effects derived from different laboratory environments were evaluated. In four selected accessions, distinct stomatal initiation processes were quantitatively analysed. Key Results and Conclusions Substantial genetic variation was found for all six stomatal abundance-related traits, which were weakly or not affected by laboratory maternal environments. Correlation analyses revealed overall relationships among all traits. Within each organ, stomatal density highly correlated with the other traits, suggesting common genetic bases. Each trait correlated between organs, supporting supra-organ control of stomatal abundance. Clustering analyses identified accessions with uncommon phenotypic patterns, suggesting differences among genetic programmes controlling the various traits. Variation was also found in organ size, which negatively correlated with cell densities in both organs and with stomatal index in the cotyledon. Relative proportions of primary and satellite lineages varied among the accessions analysed, indicating that distinct developmental components contribute to natural diversity in stomatal abundance. Accessions with similar stomatal indices showed different lineage class ratios, revealing hidden developmental phenotypes and showing that genetic determinants of primary and

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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)

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. Computer aided indexing at NASA

    NASA Technical Reports Server (NTRS)

    Buchan, Ronald L.

    1987-01-01

    The application of computer technology to the construction of the NASA Thesaurus and in NASA Lexical Dictionary development is discussed in a brief overview. Consideration is given to the printed and online versions of the Thesaurus, retrospective indexing, the NASA RECON frequency command, demand indexing, lists of terms by category, and the STAR and IAA annual subject indexes. The evolution of computer methods in the Lexical Dictionary program is traced, from DOD and DOE subject switching to LCSH machine-aided indexing and current techniques for handling natural language (e.g., the elimination of verbs to facilitate breakdown of sentences into words and phrases).

  14. 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

  15. 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.

  16. Semiotics and Indexing: An Analysis of the Subject Indexing Process.

    ERIC Educational Resources Information Center

    Mai, Jens-Erik

    2001-01-01

    Explains some major problems related to the subject indexing process and proposes semiotics as a framework for understanding the interpretive nature of the process. Explores the approach to studies of indexing and library and information science suggested by Fairthorne, Blair, Benediktsson, and others. Offers an explanation of what occurs in the…

  17. Malaysian Education Index (MEI): An Online Indexing and Repository System

    ERIC Educational Resources Information Center

    Kabilan, Muhammad Kamarul; Ismail, Hairul Nizam; Yaakub, Rohizani; Yusof, Najeemah Mohd; Idros, Sharifah Noraidah Syed; Umar, Irfan Naufal; Arshad, Muhammad Rafie Mohd.; Idrus, Rosnah; Rahman, Habsah Abdul

    2010-01-01

    This "Project Sheet" describes an on-going project that is being carried out by a group of educational researchers, computer science researchers and librarians from Universiti Sains Malaysia, Penang. The Malaysian Education Index (MEI) has two main functions--(1) Online Indexing System, and (2) Online Repository System. In this brief…

  18. Environmental Terminology Index (Permuted Index). Volume 2. Preliminary Edition.

    ERIC Educational Resources Information Center

    Oak Ridge National Lab., TN.

    This Environmental Terminology Index or Thesaurus was developed to help meet the urgent need for world-wide communication on practical as well as basic environmental problems. This working draft of the Index includes terms in the areas of physical sciences, social sciences, earth sciences, biology, and ecology. This edition of the thesaurus…

  19. 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.

  20. Birthweight for length: ponderal index, body mass index or Benn index?

    PubMed

    Cole, T J; Henson, G L; Tremble, J M; Colley, N V

    1997-01-01

    This study compares how effectively the ponderal index and the body mass index adjust birthweight for length at different gestations, and derives an improved index suitable for all gestations. The study was a cross-sectional survey, in a London teaching hospital, using a total of 999 neonates of 33 weeks gestation or later. Main outcome measures were the ponderal index (birthweight/length3), body mass index (birthweight/length2), and Benn index (birthweight/length(n)), where the length power n varies with gestation and is estimated by log-log regression. Results showed that up to 39 weeks gestation, the ponderal index is uncorrelated with length and so is a good index of birthweight for length. Past 39 weeks gestation, the ponderal index is negatively correlated with length, while the body mass index is uncorrelated, so that the body mass index is better. Neither index is optimal at all gestations. Deriving the Benn index (birthweight/length(n)) for each week of gestation, choosing n to make the index uncorrelated with length, shows that n falls steadily and very significantly (p < 0.0001) with increasing gestation. This in turn means that predicted birthweight for length depends on gestation: for a neonate 48 cm long, predicted birthweight varies from 2485 g at 34 weeks to 3030 g at 43 weeks, a 20% range. However, for a 54 cm long infant, predicted birthweight is the same at all gestations. A Benn index where the value of n changes linearly with gestation is described. We conclude that the ponderal index is not appropriate for measuring intra-uterine malnutrition, as it fails to adjust for length at all gestations. No other index of birthweight/length(n) with constant n is any better, as different gestations require different indices. Birthweight predicted from an infant's length depends on the infant's gestation. If, as Barker proposes, thinness at birth assessed by birthweight for length is used to predict later health status, more account needs to be taken of

  1. The Pemberton Happiness Index

    PubMed Central

    Paiva, Bianca Sakamoto Ribeiro; de Camargos, Mayara Goulart; Demarzo, Marcelo Marcos Piva; Hervás, Gonzalo; Vázquez, Carmelo; Paiva, Carlos Eduardo

    2016-01-01

    Abstract The Pemberton Happiness Index (PHI) is a recently developed integrative measure of well-being that includes components of hedonic, eudaimonic, social, and experienced well-being. The PHI has been validated in several languages, but not in Portuguese. Our aim was to cross-culturally adapt the Universal Portuguese version of the PHI and to assess its psychometric properties in a sample of the Brazilian population using online surveys. An expert committee evaluated 2 versions of the PHI previously translated into Portuguese by the original authors using a standardized form for assessment of semantic/idiomatic, cultural, and conceptual equivalence. A pretesting was conducted employing cognitive debriefing methods. In sequence, the expert committee evaluated all the documents and reached a final Universal Portuguese PHI version. For the evaluation of the psychometric properties, the data were collected using online surveys in a cross-sectional study. The study population included healthcare professionals and users of the social network site Facebook from several Brazilian geographic areas. In addition to the PHI, participants completed the Satisfaction with Life Scale (SWLS), Diener and Emmons’ Positive and Negative Experience Scale (PNES), Psychological Well-being Scale (PWS), and the Subjective Happiness Scale (SHS). Internal consistency, convergent validity, known-group validity, and test–retest reliability were evaluated. Satisfaction with the previous day was correlated with the 10 items assessing experienced well-being using the Cramer V test. Additionally, a cut-off value of PHI to identify a “happy individual” was defined using receiver-operating characteristic (ROC) curve methodology. Data from 1035 Brazilian participants were analyzed (health professionals = 180; Facebook users = 855). Regarding reliability results, the internal consistency (Cronbach alpha = 0.890 and 0.914) and test–retest (intraclass correlation coefficient = 0.814) were

  2. How To Create a Great Index.

    ERIC Educational Resources Information Center

    Wilson, Bradley

    2003-01-01

    Contends that the index at the back of a book is an important reader service. Discusses how and why to index, and how to make indexes interesting. Outlines programs, such as Filemaker and Adobe, which help the indexing process. (PM)

  3. Macrobenthos composition, distribution and abundance within Sungai Pulai estuary, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Shi, Guan Wan; Min, Lee Di; Ghaffar, Mazlan Abd; Ali, Masni Md; Cob, Zaidi Che

    2014-09-01

    Macrobenthos are very useful organisms for monitoring marine environmental and widely use in marine ecology research. They are able to monitor the difference phase in the recovery stage of disturbed sites by appear different species macrobenthos after the cessation of the impact. Univariate and multivariate methods were use to study the macrobenthos community within Sungai Pulai estuary, Johor, Malaysia. Five sub-samples were taken at each sampling sites by using 10 cm diameter corer. Crustaceans were the most abundant at Tanjung Adang (St. 1) and the station of non-seagrass area (St. 2) while polychaetes were the most abundant at Merambong Shoal (St. 3). Higher density of macrobenthos was found at St.3 followed by St. 1 and St. 2. The commonly used population indices such as diversity, richness, evenness and dominance were employed to determine the differences in diversity and abundance of macrobenthos. The diversity, richness and evenness index values showed slight increment from Station 1 to Station 3, while the dominance index decreasing trend from Station 1 to Station 3. A total 21 polychaete families were collected in Sungai Pulai estuary, which was dominated by the Spionidae, Capitellidae and Glyceridae. Cluster (Bray-Curtis similarities) analyses revealed that the Tanjung Adang and Merambong Shoal population were clearly separated from the station non-seagrass. For the time being factors that influence the pattern of distribution of the macrobenthos cannot be determined and subjected to further studies.

  4. Simplifying the Water Poverty Index

    ERIC Educational Resources Information Center

    Cho, Danny I.; Ogwang, Tomson; Opio, Christopher

    2010-01-01

    In this paper, principal components methodology is used to derive simplified and cost effective indexes of water poverty. Using a well known data set for 147 countries from which an earlier five-component water poverty index comprising of "Resources," "Access," "Capacity," "Use" and "Environment" was constructed, we find that a simplified…

  5. The Earliest Hebrew Citation Indexes.

    ERIC Educational Resources Information Center

    Weinberg, Bella Hass

    1997-01-01

    Describes early Hebrew citation indexes, both embedded and book-length, and discusses terminological variation, format, precision of locators, the order of index entries and assumption of user knowledge, knowledge of the compilers, and recommendations for further research. (59 references) (LRW)

  6. Estrada index and Chebyshev polynomials

    NASA Astrophysics Data System (ADS)

    Ginosar, Yuval; Gutman, Ivan; Mansour, Toufik; Schork, Matthias

    2008-03-01

    Let G be a graph whose eigenvalues are λ1, λ2,…, λn. The Estrada index of G is equal to ∑i=1ne. We point out certain classes of graphs whose characteristic polynomials are closely connected to the Chebyshev polynomials of the second kind. Various relations, in particular approximations, for the Estrada index of these graphs are obtained.

  7. Index of Refraction without Geometry

    ERIC Educational Resources Information Center

    Farkas, N.; Henriksen, P. N.; Ramsier, R. D.

    2006-01-01

    This article presents several activities that permit students to determine the index of refraction of transparent solids and liquids using simple equipment without the need for geometrical relationships, special lighting or optical instruments. Graphical analysis of the measured data is shown to be a useful method for determining the index of…

  8. Linguistic Indexicality in Algebra Discussions

    ERIC Educational Resources Information Center

    Staats, Susan; Batteen, Chris

    2010-01-01

    In discussion-oriented classrooms, students create mathematical ideas through conversations that reflect growing collective knowledge. Linguistic forms known as indexicals assist in the analysis of this collective, negotiated understanding. Indexical words and phrases create meaning through reference to the physical, verbal and ideational context.…

  9. Indexing by Latent Semantic Analysis.

    ERIC Educational Resources Information Center

    Deerwester, Scott; And Others

    1990-01-01

    Describes a new method for automatic indexing and retrieval called latent semantic indexing (LSI). Problems with matching query words with document words in term-based information retrieval systems are discussed, semantic structure is examined, singular value decomposition (SVD) is explained, and the mathematics underlying the SVD model is…

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. [ATD index in Perthes disease].

    PubMed

    Grzegorzewski, Andrzej; Synder, Marek; Szymczak, Wiesław; Kowalewski, Maciej; Kozłowski, Piotr

    2003-01-01

    Authors present an estimation of articulo-trochanteric-distance (ATD) and ATD index in patients with Perthes disease and if there is any correlation between ATD and ATD index and age at the onset, gender, type of treatment, Herring and Stulberg classification. The study population consisted of 242 patients (35 female and 207 male) who had reached skeletal maturity at last follow up. The mean age at the onset of symptoms was 7 years and 4 months. All patients were treated by containment methods (bed rest and traction in abduction, brace, Petri cast, varus osteotomy, Salter osteotomy and shelf operation). ATD was estimated according to the Edgren methods and ATD index was calculated as relation ATD on Perthes site to ATD in normal joint. The late results were classified according to the Stulberg classification. Statistical analysis did not revealed any correlation between the age at the onset, gender and ATD index and ATD during last follow up. Both parameters decreased with poor results according to the Stulberg classifications. ATD index and ATD were statistically significant less after surgical treatment than after non-operative treatment. The same relations were seen between patients with leg length discrepancy (LLD) and without LLD. Patients in Herring group A had statistically significant bigger both parameters than patients in group B, C and patients in Herring group B than C. Articulo-trochanteric-distance and ATD index decreased during follow up and ATD decreased also in normal joint. In our opinion ATD index is a more reliable radiological parameter than ATD. ATD index decreases with bigger necrosis of the femoral head and poor result according to the Stulberg classification. This parameter is an evidence of the dysfunction proximal femoral growth plate in patients with LLD. The most decreased ATD index was observed after surgical treatment. There was no correlation between the age at the onset, gender and ATD index at last follow up.

  17. Source Indexing in Science Journals and Indexing Services: A Survey of Current Practices.

    ERIC Educational Resources Information Center

    Diodato, Virgil; Pearson, Karen

    1986-01-01

    Study of state of source indexing (indexing data published simultaneously with articles they represent) examines aspects of 685 science journals: science fields using source indexing; source indexing formats; assignment of indexing terms from controlled vocabularies; suppliers of indexing (authors, editors, indexers); use of source indexing by…

  18. Retrospective indexing (RI) - A computer-aided indexing technique

    NASA Technical Reports Server (NTRS)

    Buchan, Ronald L.

    1990-01-01

    An account is given of a method for data base-updating designated 'computer-aided indexing' (CAI) which has been very efficiently implemented at NASA's Scientific and Technical Information Facility by means of retrospective indexing. Novel terms added to the NASA Thesaurus will therefore proceed directly into both the NASA-RECON aerospace information system and its portion of the ESA-Information Retrieval Service, giving users full access to material thus indexed. If a given term appears in the title of a record, it is given special weight. An illustrative graphic representation of the CAI search strategy is presented.

  19. Index to NASA News Releases 1995

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This issue of the index to NASA News Releases contains a listing of news releases distributed by the Office of Public Affairs, NASA Headquarters, during 1995. The index is arranged in six sections: Subject index, Personal name index, News release number index, Accession number index, Speeches, and News releases.

  20. Is the Multicolored Asian Ladybeetle, Harmonia axyridis, the Most Abundant Natural Enemy to Aphids in Agroecosystems?

    PubMed Central

    Vandereycken, Axel; Durieux, Delphine; Joie, Emilie; Sloggett, John J.; Haubruge, Eric; Verheggen, François J.

    2013-01-01

    The multicolored Asian ladybeetle, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), was introduced into Western Europe in the late 1990s. Since the late 2000s, this species has been commonly considered one of the most abundant aphid predators in most Western European countries. In spite of the large amount of research on H. axyridis, information concerning its relative abundance in agroecosystems is lacking. This study aims to evaluate the abundance of H. axyridis within the aphidophage community in four crops situated in southern Belgium: wheat, Triticum aestivum L. (Poales: Poaceae), corn, Zea mays, potato, Solanum tuberosum (Solanales: Solanaceae), and broad bean Vicia faba (Fabales: Fabaceae). In order to assess the species diversity, the collected data were analyzed by considering (1) the species richness and (2) the evenness according to the Shannon diversity index. Eleven aphidophages were observed in every inventoried agroecosystem, including five abundant species: three coccinellids, the seven-spotted ladybug, Coccinella septempunctata L. (Coleoptera: Coccinellidae), the 14-spotted Ladybird, Propylea quatuordecimpunctata, and H. axyridis; one hoverfly, the marmalade hoverfly, Episyrphus balteatus De Geer (Diptera: Syrphidae); and one lacewing, the common green lacewing, Chrysoperla carnea Stephens sensu lato (= s.l.) (Neuroptera: Chrysopidae). Harmonia axyridis has been observed to thrive, breed, and reproduce on the four studied crops. Harmonia axyridis is the most abundant predator of aphids in corn followed by C. septempunctata, which is the main aphid predator observed in the three other inventoried crops. In wheat and potato fields, H. axyridis occurs in low numbers compared to other aphidophage. These observations suggest that H. axyridis could be considered an invasive species of agrosystems, and that potato and wheat may intermittently act as refuges for other aphidophages vulnerable to intraguild predation by this invader. Harmonia axyridis

  1. Seasonal and interannual variations in coccolithophore abundance off Terceira Island, Azores (Central North Atlantic)

    NASA Astrophysics Data System (ADS)

    Narciso, Áurea; Gallo, Francesca; Valente, André; Cachão, Mário; Cros, Lluïsa; Azevedo, Eduardo B.; e Ramos, Joana Barcelos

    2016-04-01

    In order to characterize the natural coccolithophore community occurring offshore Azores and to determine their annual and interannual patterns, monthly samples were collected, from September 2010 to December 2014, in the photic zone off Terceira Island. The present study revealed a clear seasonal distribution and a considerable interannual variability of the living coccolithophore community. The highest coccolithophore abundances were observed during spring and winter months, especially due to the smaller species Emiliania huxleyi and Gephyrocapsa ericsonii. In fact, the highest biomass period was registered during April 2011, associated with enhanced abundance of the overcalcified morphotype of E. huxleyi, which was possibly influenced by subpolar waters and subsequent upwelling conditions. The highest abundances of Gephyrocapsa muellerae were recorded during June 2011 and 2014, indicating that this species characterizes the transition between the period of maximum productivity and the subsequent smoother environmental conditions, the first and the later stages of the phytoplankton succession described by Margalef, respectively. During summer to early fall, a gradual decrease of the overall coccolithophore abundance was observed, while the species richness (Margalef diversity index) increased. A subtropical coccolithophore assemblage mainly composed by Umbellosphaera tenuis, Syracosphaera spp., Discosphaera tubifera, Rhabdosphaera clavigera and Coronosphaera mediterranea indicated the presence of surface warmer waters accompanied by reduced mixing and low nutrients concentration. During late fall to winter, the coccolithophore abundance increased again with a concomitant reduction in species diversity. This is potentially linked to low sea surface temperatures, moderate nutrients concentration and surface mixed layer deepening. During 2011, colder and productive waters led to an increase in the total coccolithophore abundances. On contrary, during 2012

  2. 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.

  3. 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.

  4. Assessing small mammal abundance with track-tube indices and mark-recapture population estimates

    USGS Publications Warehouse

    Wiewel, A.S.; Clark, W.R.; Sovada, M.A.

    2007-01-01

    We compared track-tube sampling with mark-recapture livetrapping and evaluated a track-tube index, defined as the number of track tubes with identifiable small mammal tracks during a 4-night period, as a predictor of small mammal abundance estimates in North Dakota grasslands. Meadow voles (Microtus pennsylvanicus) were the most commonly recorded species by both methods, but were underrepresented in track-tube sampling, whereas 13-lined ground squirrels (Spermophilus tridecemlineatus) and Franklin's ground squirrels (S. franklinii) were overrepresented in track-tube sampling. Estimates of average species richness were lower from track tubes than from livetrapping. Regression models revealed that the track-tube index was at best a moderately good predictor of small mammal population estimates because both the form (linear versus curvilinear) and slope of the relationship varied between years. In addition, 95% prediction intervals indicated low precision when predicting population estimates from new track-tube index observations. Track tubes required less time and expense than mark-recapture and eliminated handling of small mammals. Using track tubes along with mark-recapture in a double sampling for regression framework would have potential value when attempting to estimate abundance of small mammals over large areas. ?? 2007 American Society of Mammalogists.

  5. Climate warming increases biodiversity of small rodents by favoring rare or less abundant species in a grassland ecosystem.

    PubMed

    Jiang, Guangshun; Liu, Jun; Xu, Lei; Yu, Guirui; He, Honglin; Zhang, Zhibin

    2013-06-01

    Our Earth is facing the challenge of accelerating climate change, which imposes a great threat to biodiversity. Many published studies suggest that climate warming may cause a dramatic decline in biodiversity, especially in colder and drier regions. In this study, we investigated the effects of temperature, precipitation and a normalized difference vegetation index on biodiversity indices of rodent communities in the current or previous year for both detrended and nondetrended data in semi-arid grassland of Inner Mongolia during 1982-2006. Our results demonstrate that temperature showed predominantly positive effects on the biodiversity of small rodents; precipitation showed both positive and negative effects; a normalized difference vegetation index showed positive effects; and cross-correlation function values between rodent abundance and temperature were negatively correlated with rodent abundance. Our results suggest that recent climate warming increased the biodiversity of small rodents by providing more benefits to population growth of rare or less abundant species than that of more abundant species in Inner Mongolia grassland, which does not support the popular view that global warming would decrease biodiversity in colder and drier regions. We hypothesized that higher temperatures might benefit rare or less abundant species (with smaller populations and more folivorous diets) by reducing the probability of local extinction and/or by increasing herbaceous food resources.

  6. LITHIUM ABUNDANCE IN SOLAR-TYPE STARS WITH LOW CHROMOSPHERIC ACTIVITY: APPLICATION TO THE SEARCH FOR MAUNDER MINIMUM ANALOGS

    SciTech Connect

    Lubin, Dan; Tytler, David; Kirkman, David

    2010-06-10

    We use measurements of lithium abundance to examine the evolutionary history of stars frequently believed to be in a Maunder minimum (MM) state due to their low chromospheric activity. In a sample whose main-sequence membership has been verified using Hipparcos parallax data, we find that stars with very low chromospheric activity log R'{sub HK} {<=} -5.0 have substantially depleted lithium compared with the full sample, with half of these lithium abundances lying more than one standard deviation below the sample mean for their range of color index. One interpretation is that these stars are near the end of their main-sequence lifetime, and therefore their low activity does not necessarily signify a transient MM state in a solar-age star. Conversely, using information in published activity time series for some stars, and combined lithium and activity measurements from the Ursa Major moving group and M67, we find limited evidence that a low-activity star having lithium abundance in the normal range for its color index may be a viable MM candidate. Thus, lithium abundance, which can be readily observed or even retrieved from some of the spectroscopic data collected by recent planet-search surveys, may have value for expanding and refining the program star lists for long-term MM searches. Finally, we find that the use of Hipparcos parallax data to ascertain main-sequence membership sharpens the distinction in sample-mean lithium abundance between stars with planet detections and comparison stars.

  7. Filling a void: abundance estimation of North American populations of arctic geese using hunter recoveries

    USGS Publications Warehouse

    Alisauskas, R.T.; Drake, K.L.; Nichols, J.D.; Thomson, David L.; Cooch, Evan G.; Conroy, Michael J.

    2009-01-01

    We consider use of recoveries of marked birds harvested by hunters, in conjunction with continental harvest estimates, for drawing inferences about continental abundance of a select number of goose species. We review assumptions of this method, a version of the Lincoln?Petersen approach, and consider its utility as a tool for making decisions about harvest management in comparison to current sources of information. Finally, we compare such estimates with existing count data, photographic estimates, or other abundance estimates. In most cases, Lincoln estimates are far higher than abundances assumed or perhaps accepted by many waterfowl biologists and managers. Nevertheless, depending on the geographic scope of inference, we suggest that this approach for abundance estimation of arctic geese may have usefulness for retrospective purposes or to assist with harvest management decisions for some species. Lincoln?s estimates may be as close or closer to truth than count, index, or photo data, and can be used with marking efforts currently in place for estimation of survival and harvest rates. Although there are bias issues associated with estimates of both harvest and harvest rate, some of the latter can be addressed with proper allocation of marks to spatially structured populations if subpopulations show heterogeneity in harvest rates.

  8. Fingerprints of anomalous primordial Universe on the abundance of large scale structures

    NASA Astrophysics Data System (ADS)

    Baghram, Shant; Akbar Abolhasani, Ali; Firouzjahi, Hassan; Namjoo, Mohammad Hossein

    2014-12-01

    We study the predictions of anomalous inflationary models on the abundance of structures in large scale structure observations. The anomalous features encoded in primordial curvature perturbation power spectrum are (a): localized feature in momentum space, (b): hemispherical asymmetry and (c): statistical anisotropies. We present a model-independent expression relating the number density of structures to the changes in the matter density variance. Models with localized feature can alleviate the tension between observations and numerical simulations of cold dark matter structures on galactic scales as a possible solution to the missing satellite problem. In models with hemispherical asymmetry we show that the abundance of structures becomes asymmetric depending on the direction of observation to sky. In addition, we study the effects of scale-dependent dipole amplitude on the abundance of structures. Using the quasars data and adopting the power-law scaling knA-1 for the amplitude of dipole we find the upper bound nA < 0.6 for the spectral index of the dipole asymmetry. In all cases there is a critical mass scale Mc in which for M Mc) the enhancement in variance induced from anomalous feature decreases (increases) the abundance of dark matter structures in Universe.

  9. Effect of habitat complexity on richness, abundance and distributional pattern of forest birds.

    PubMed

    Ghadiri Khanaposhtani, Maryam; Kaboli, Mohammad; Karami, Mahmoud; Etemad, Vahid

    2012-08-01

    Structurally complex forests provide more diverse conditions in comparison to homogenous forests because of greater variety of microhabitats and trees. This study assesses the association of bird species richness, abundance, and distributional pattern with habitat complexity (HC) in Kheyrud Forest in the north of Iran. Birds were surveyed during spring 2009 by 100 point counts. In each point count six habitat features related to the index of HC were computed and scored from 0 to 3. Then the scores were summed and divided into two groups of low and high complexity, HC ≤ 6 and HC > 6, respectively. To compare bird richness and abundance in different HCs, a two sample t-test was used. Presence and absence of bird species at each plot as a dependent variable were compared with the vegetation characteristics as an independent variable by means of the Canonical Correspondence Analysis. The results revealed bird species richness and abundance were significantly higher in more complex habitats. Bird species can be divided into two groups, the first group including species which associated with late successional stages and the second group, species belonging to early successional stages. Numbers of birds belonging to the first group declined in less complex forests, whereas the numbers of birds belonging to the second group increased. At the stand scale, our results reveal that bird abundance and richness are strongly associated with the complexity of vegetation structure in the study area.

  10. Effect of Habitat Complexity on Richness, Abundance and Distributional Pattern of Forest Birds

    NASA Astrophysics Data System (ADS)

    Ghadiri Khanaposhtani, Maryam; Kaboli, Mohammad; Karami, Mahmoud; Etemad, Vahid

    2012-08-01

    Structurally complex forests provide more diverse conditions in comparison to homogenous forests because of greater variety of microhabitats and trees. This study assesses the association of bird species richness, abundance, and distributional pattern with habitat complexity (HC) in Kheyrud Forest in the north of Iran. Birds were surveyed during spring 2009 by 100 point counts. In each point count six habitat features related to the index of HC were computed and scored from 0 to 3. Then the scores were summed and divided into two groups of low and high complexity, HC ≤ 6 and HC > 6, respectively. To compare bird richness and abundance in different HCs, a two sample t-test was used. Presence and absence of bird species at each plot as a dependent variable were compared with the vegetation characteristics as an independent variable by means of the Canonical Correspondence Analysis. The results revealed bird species richness and abundance were significantly higher in more complex habitats. Bird species can be divided into two groups, the first group including species which associated with late successional stages and the second group, species belonging to early successional stages. Numbers of birds belonging to the first group declined in less complex forests, whereas the numbers of birds belonging to the second group increased. At the stand scale, our results reveal that bird abundance and richness are strongly associated with the complexity of vegetation structure in the study area.

  11. Seasonal Abundance and Host-Feeding Patterns of Anopheline Vectors in Malaria Endemic Area of Iran

    PubMed Central

    Basseri, Hamidreza; Raeisi, Ahmad; Ranjbar Khakha, Mansoor; Pakarai, Abaas; Abdolghafar, Hassanzehi

    2010-01-01

    Seasonal abundance and tendency to feed on humans are important parameters to measure for effective control of malaria vectors. The objective of this study was to describe relation between feeding pattern, abundance, and resting behavior of four malaria vectors in southern Iran. This study was conducted in ten indicator villages (based on malaria incidence and entomological indices) in mountainous/hilly and plain regions situated south and southeastern Iran. Mosquito vectors were collected from indoor as well as outdoor shelters and the blood meals were examined by ELISA test. Over all 7654 female Anopheles spp. were captured, the most common species were Anopheles stephensi, An. culicifacies, An. fluviatilis, and An. d'thali. The overall human blood index was 37.50%, 19.83%, 16.4%, and 30.1% for An. fluviatilis, An. stephensi, An. culicifacies, and An. d'thali, respectively. In addition, An. fluviatilis fed on human blood during the entire year but the feeding behavior of An. stephensi and An. culicifacies varied according to seasons. Overall, the abundance of the female mosquito positive to human blood was 4.25% per human shelter versus 17.5% per animal shelter. This result indicates that the vectors had tendency to rest in animal shelters after feeding on human. Therefore, vector control measure should be planned based on such as feeding pattern, abundance, and resting behavior of these vectors in the area. PMID:21559055

  12. Fingerprints of anomalous primordial Universe on the abundance of large scale structures

    SciTech Connect

    Baghram, Shant; Abolhasani, Ali Akbar; Firouzjahi, Hassan; Namjoo, Mohammad Hossein E-mail: abolhasani@ipm.ir E-mail: MohammadHossein.Namjoo@utdallas.edu

    2014-12-01

    We study the predictions of anomalous inflationary models on the abundance of structures in large scale structure observations. The anomalous features encoded in primordial curvature perturbation power spectrum are (a): localized feature in momentum space, (b): hemispherical asymmetry and (c): statistical anisotropies. We present a model-independent expression relating the number density of structures to the changes in the matter density variance. Models with localized feature can alleviate the tension between observations and numerical simulations of cold dark matter structures on galactic scales as a possible solution to the missing satellite problem. In models with hemispherical asymmetry we show that the abundance of structures becomes asymmetric depending on the direction of observation to sky. In addition, we study the effects of scale-dependent dipole amplitude on the abundance of structures. Using the quasars data and adopting the power-law scaling k{sup n{sub A}-1} for the amplitude of dipole we find the upper bound n{sub A} < 0.6 for the spectral index of the dipole asymmetry. In all cases there is a critical mass scale M{sub c} in which for M M{sub c}) the enhancement in variance induced from anomalous feature decreases (increases) the abundance of dark matter structures in Universe.

  13. Can measures of prey availability improve our ability to predict the abundance of large marine predators?

    PubMed

    Wirsing, Aaron J; Heithaus, Michael R; Dill, Lawrence M

    2007-09-01

    Apex marine predators can structure marine communities, so factors underlying their abundance are of broad interest. However, such data are almost completely lacking for large sharks. We assessed the relationship between tiger shark abundance, water temperature, and the availability of a variety of known prey over 5 years in Western Australia. Abundance of sharks in four size categories and the density of prey (cormorants, dugongs, sea snakes, sea turtles) were indexed using daily catch rates and transects, respectively. Across all sizes, thermal conditions were a determinant of abundance, with numerical peaks coinciding with periods of high water temperature. However, for sharks exceeding 300 cm total length, the inclusion of dugong density significantly improved temperature-based models, suggesting that use of particular areas by large tiger sharks is influenced by availability of this sirenian. We conclude that large marine predator population models may benefit from the inclusion of measures of prey availability, but only if such measures consider prey types separately and account for ontogenetic shifts in the diet of the predator in question.

  14. Habitat Suitability Index Models: Fallfish

    USGS Publications Warehouse

    Trial, Joan G.; Wade, Charles S.; Stanley, Jon G.; Nelson, Patrick C.

    1983-01-01

    A review and synthesis of existing information were used to develop riverine and lacustrine habitat models for fallfish (Semotilis corporalis), a freshwater species. The models are scaled to produce an index of habitat suitability between 0 (unsuitable habitat) to 1 (optimally suitable habitat) for freshwater, marine and estuarine areas of the continental United States. Habitat suitability indexes (HSI's) are designed for use with the habitat evaluation procedures developed by the U.S. Fish and Wildlife Service. Also included are discussions of Suitability Index (SI) curves as used in the Instream Flow Incremental Methodology (IFIM) and SI curves available for an IFIM analysis of Fallfish habitat.

  15. 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

  16. 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

  17. 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

  18. 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

  19. Consideraciones para la estimacion de abundancia de poblaciones de mamiferos. [Considerations for the estimation of abundance of mammal populations.

    USGS Publications Warehouse

    Walker, R.S.; Novare, A.J.; Nichols, J.D.

    2000-01-01

    Estimation of abundance of mammal populations is essential for monitoring programs and for many ecological investigations. The first step for any study of variation in mammal abundance over space or time is to define the objectives of the study and how and why abundance data are to be used. The data used to estimate abundance are count statistics in the form of counts of animals or their signs. There are two major sources of uncertainty that must be considered in the design of the study: spatial variation and the relationship between abundance and the count statistic. Spatial variation in the distribution of animals or signs may be taken into account with appropriate spatial sampling. Count statistics may be viewed as random variables, with the expected value of the count statistic equal to the true abundance of the population multiplied by a coefficient p. With direct counts, p represents the probability of detection or capture of individuals, and with indirect counts it represents the rate of production of the signs as well as their probability of detection. Comparisons of abundance using count statistics from different times or places assume that the p are the same for all times or places being compared (p= pi). In spite of considerable evidence that this assumption rarely holds true, it is commonly made in studies of mammal abundance, as when the minimum number alive or indices based on sign counts are used to compare abundance in different habitats or times. Alternatives to relying on this assumption are to calibrate the index used by testing the assumption of p= pi, or to incorporate the estimation of p into the study design.

  20. Patterns of variability in ichthyoplankton occurrence and abundance in Biscayne Bay, Florida

    NASA Astrophysics Data System (ADS)

    Houde, Edward D.; Alpern Lovdal, Jamie D.

    1985-01-01

    Within-day variability in ichthyoplankton and microzooplankton abundances was examined at a single station in Biscayne Bay using replicate tows of 61-cm bongo nets and Niskin bottles to determine if patchiness occurred on the 10-1000 m scale and on the minutes to hours time scale. Fish eggs and larvae often were patchy but copepod nauplii, the predominant food of larvae, usually were randomly distributed at the scales examined and over the 3.15 m-depth water column. Mean patchiness index values were of similar magnitude for fish eggs and larvae but fish eggs were patchy more often than were larvae. Individual taxa of larvae had extremely high patchiness index values on some dates. Variability in fish egg catches often reflected increasing or decreasing abundance trends during the 2.5h sampling period while fish larvae catches often appeared to be clumped within the repetitive series of tows. There was no tendency for patchiness to be correlated among taxa on collection dates nor was it correlated with abundances or wind speeds. Patchiness indices of bay anchovy Anchoa mitchilli eggs and larvae were not significantly correlated, indicating little concordance in tendency to be aggregated, suggesting that distributions were influenced by biological processes related to spawning of adults and behaviour of larvae, in addition to physical processes. Although ichthyoplankton patchiness often did exist at the 10-1000 m scale, on many days ichthyoplankton was uniformly or randomly distributed. Copepod nauplii were abundant ( overlinex=90.41 -1), randomly distributed on most dates, and apparently readily available as fish larvae food in Biscayne Bay.

  1. Greater deciduous shrub abundance extends tundra peak season and increases modeled net CO2 uptake.

    PubMed

    Sweet, Shannan K; Griffin, Kevin L; Steltzer, Heidi; Gough, Laura; Boelman, Natalie T

    2015-06-01

    Satellite studies of the terrestrial Arctic report increased summer greening and longer overall growing and peak seasons since the 1980s, which increases productivity and the period of carbon uptake. These trends are attributed to increasing air temperatures and reduced snow cover duration in spring and fall. Concurrently, deciduous shrubs are becoming increasingly abundant in tundra landscapes, which may also impact canopy phenology and productivity. Our aim was to determine the influence of greater deciduous shrub abundance on tundra canopy phenology and subsequent impacts on net ecosystem carbon exchange (NEE) during the growing and peak seasons in the arctic foothills region of Alaska. We compared deciduous shrub-dominated and evergreen/graminoid-dominated community-level canopy phenology throughout the growing season using the normalized difference vegetation index (NDVI). We used a tundra plant-community-specific leaf area index (LAI) model to estimate LAI throughout the green season and a tundra-specific NEE model to estimate the impact of greater deciduous shrub abundance and associated shifts in both leaf area and canopy phenology on tundra carbon flux. We found that deciduous shrub canopies reached the onset of peak greenness 13 days earlier and the onset of senescence 3 days earlier compared to evergreen/graminoid canopies, resulting in a 10-day extension of the peak season. The combined effect of the longer peak season and greater leaf area of deciduous shrub canopies almost tripled the modeled net carbon uptake of deciduous shrub communities compared to evergreen/graminoid communities, while the longer peak season alone resulted in 84% greater carbon uptake in deciduous shrub communities. These results suggest that greater deciduous shrub abundance increases carbon uptake not only due to greater leaf area, but also due to an extension of the period of peak greenness, which extends the period of maximum carbon uptake.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. Ozone - Current Air Quality Index

    MedlinePlus

    Local Air Quality Conditions Zip Code: State : My Current Location Forecast Current AQI AQI Loop More Maps AQI: Good (0 - ... September 2016, Busan, South Korea. More more announcements Air Quality Basics Air Quality Index | Ozone | Particle Pollution | Smoke ...

  10. Antimicrobial Pesticide Use Site Index

    EPA Pesticide Factsheets

    This Use Site Index provides guidance to assist applicants for antimicrobial pesticide registration by helping them identify the data requirements necessary to register a pesticide or support their product registrations.

  11. Environmental Quality Index - Overview Report

    EPA Science Inventory

    A better estimate of overall environmental quality is needed to improve our understanding of the relationship between environmental conditions and humanhealth. Described in this report is the effort to construct an environmental quality index representing multiple domains of the ...

  12. Stator Indexing in Multistage Compressors

    NASA Technical Reports Server (NTRS)

    Barankiewicz, Wendy S.

    1997-01-01

    The relative circumferential location of stator rows (stator indexing) is an aspect of multistage compressor design that has not yet been explored for its potential impact on compressor aerodynamic performance. Although the inlet stages of multistage compressors usually have differing stator blade counts, the aft stages of core compressors can often have stage blocks with equal stator blade counts in successive stages. The potential impact of stator indexing is likely greatest in these stages. To assess the performance impact of stator indexing, researchers at the NASA Lewis Research Center used the 4 ft diameter, four-stage NASA Low Speed Axial Compressor for detailed experiments. This compressor has geometrically identical stages that can circumferentially index stator rows relative to each other in a controlled manner; thus it is an ideal test rig for such investigations.

  13. Energy Index For Aircraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Chidester, Thomas R. (Inventor); Lynch, Robert E. (Inventor); Lawrence, Robert E. (Inventor); Amidan, Brett G. (Inventor); Ferryman, Thomas A. (Inventor); Drew, Douglas A. (Inventor); Ainsworth, Robert J. (Inventor); Prothero, Gary L. (Inventor); Romanowski, Tomothy P. (Inventor); Bloch, Laurent (Inventor)

    2006-01-01

    Method and system for analyzing, separately or in combination, kinetic energy and potential energy and/or their time derivatives, measured or estimated or computed, for an aircraft in approach phase or in takeoff phase, to determine if the aircraft is or will be put in an anomalous configuration in order to join a stable approach path or takeoff path. A 3 reference value of kinetic energy andor potential energy (or time derivatives thereof) is provided, and a comparison index .for the estimated energy and reference energy is computed and compared with a normal range of index values for a corresponding aircraft maneuver. If the computed energy index lies outside the normal index range, this phase of the aircraft is identified as anomalous, non-normal or potentially unstable.

  14. Statistical Approaches to Automatic Indexing.

    ERIC Educational Resources Information Center

    Harter, Stephen P.

    1978-01-01

    Views automatic indexing as a two-tiered word frequency analysis that involves selection of a technical vocabulary and identification of document keywords. Assumptions, criteria, evaluation, and relevance are discussed. (JD)

  15. Tomographic study of shapes and metal abundances of Renazzo chondrules

    SciTech Connect

    Hertz, J.; Ebel, Denton; Weisberg, W.K.

    2003-05-19

    Analysis of 3-dimensional tomographic data for 3 Renazzo chondrules shows that 2-D thin section methods are inadequate to quantify 'convolution index', grain sizes and distributions, or modal metal abundance, but 3-D methods are more promising. The origin of metal in the metalrich, highly primitive, CR2 chondrites is vigorously debated. In some Renazzo chondrules, metal has an approximately solar Ni:Co ratio which led to suggest that it is a product of solar nebula condensation. Additionally, in many chondrules, metal occurs in two locations: as one or two large metal grains in the chondrule interior and as numerous smaller metal grains along the chondrule rim. In other chondrules, metal is more evenly dispersed in smaller grains. Interior metal generally has higher concentrations of the more refractory siderophile elements than metal in the rim, which tends to be enriched in volatile metals. This difference may be due to (1) partial evaporation and rapid recondensation of metal; (2) condensation of core metal at higher temperatures, suggesting accretionary growth of the chondrules as temperature decreased; or (3) late Fe addition to the metal on the chondrule rims due to FeO reduction from the adjoining silicates. [4] analyzed PGE distribution in CR chondrite metal and argued that rim metal may have formed by a reaction with the surrounding silicates at the time of chondrule formation. [5] showed that Ni and Co concentrations in the metal grains of the least circular, finest-grained chondrules do not follow a condensation trend. This implies that the relative amounts of Ni and Co in the interior grains were gradually established during chondrule melting due to Fe oxidation or reduction. More recently, observed that chondrules that appear more circular in thin section outline also have coarser metal and silicate grains and a more clearly defined compositional differentiation between rim and core metal grains. These textures were interpreted as reflecting a higher

  16. Habitat Suitability Index Models: Bullfrog

    USGS Publications Warehouse

    Graves, Brent M.; Anderson, Stanley H.

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the bullfrog (Rana catesbeiana). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  17. Habitat Suitability Index Models: Bobcat

    USGS Publications Warehouse

    Boyle, Katherine A.; Fendley, Timothy T.

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the bobcat (Felis rufus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  18. PC index and magnetic substorms

    NASA Astrophysics Data System (ADS)

    Troshichev, Oleg; Janzhura, Alexander; Sormakov, Dmitry; Podorozhkina, Nataly

    PC index is regarded as a proxy of the solar wind energy that entered into the magnetosphere as distinct from the AL and Dst indices, which are regarded as characteristics of the energy that realize in the magnetosphere in form of substorm and magnetic storms. This conclusion is based on results of analysis of relationships between the polar cap magnetic activity (PC-index) and parameters of the solar wind, on the one hand, relationships between changes of PC and development of magnetospheric substorms (AL-index) and magnetic storms (Dst-index), on the other hand. This paper describes in detail the following main results which demonstrate a strong connection between the behavior of PC and development of magnetic disturbances in the auroral zone: (1) magnetic substorms are preceded by the РС index growth (isolated and extended substorms) or long period of stationary PC (postponed substorms), (2) the substorm sudden onsets are definitely related to such PC signatures as leap and reverse, which are indicative of sharp increase of the PC growth rate, (3) substorms generally start to develop when the PC index exceeds the threshold level ~ 1.5±0.5 mV/m, irrespective of the substorm growth phase duration and type of substorm, (4) linear dependency of AL values on PC is typical of all substorm events irrespective of type and intensity of substorm.

  19. 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.

  20. 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 .

  1. A Weathering Index for CK and R Chondrites

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.; Huber, Heinz

    2006-01-01

    We present a new weathering index (wi) for the metallic-Fe-Ni-poor chondrite groups (CK and R) based mainly on transmitted light observations of the modal abundance of crystalline material that is stained brown in thin sections: wi-0, <5 vol%; wi-1, 5-25 vol%; wi-2,25-50 vol%; wi-3,50- 75 vol%; wi-4, 75-95 vol%; wi-5, >95 vol%, wi-6, significant replacement of mafic silicates by phyllosilicates. Brown staining reflects mobilization of oxidized iron derived mainly from terrestrial weathering of Ni-bearing sulfide. With increasing degrees of terrestrial weathering of CK and R chondrites, the sulfide modal abundance decreases, and S, Se, and Ni become increasingly depleted. In addition, bulk Cl increases in Antarctic CK chondrites, probably due to contamination from airborne sea mist.

  2. Abundant Microsatellite Diversity and Oil Content in Wild Arachis Species

    PubMed Central

    Ren, Xiaoping; Chen, Yuning; Xiao, Yingjie; Zhao, Xinyan; Tang, Mei; Huang, Jiaquan; Upadhyaya, Hari D.; Liao, Boshou

    2012-01-01

    The peanut (Arachis hypogaea) is an important oil crop. Breeding for high oil content is becoming increasingly important. Wild Arachis species have been reported to harbor genes for many valuable traits that may enable the improvement of cultivated Arachis hypogaea, such as resistance to pests and disease. However, only limited information is available on variation in oil content. In the present study, a collection of 72 wild Arachis accessions representing 19 species and 3 cultivated peanut accessions were genotyped using 136 genome-wide SSR markers and phenotyped for oil content over three growing seasons. The wild Arachis accessions showed abundant diversity across the 19 species. A. duranensis exhibited the highest diversity, with a Shannon-Weaver diversity index of 0.35. A total of 129 unique alleles were detected in the species studied. A. rigonii exhibited the largest number of unique alleles (75), indicating that this species is highly differentiated. AMOVA and genetic distance analyses confirmed the genetic differentiation between the wild Arachis species. The majority of SSR alleles were detected exclusively in the wild species and not in A. hypogaea, indicating that directional selection or the hitchhiking effect has played an important role in the domestication of the cultivated peanut. The 75 accessions were grouped into three clusters based on population structure and phylogenic analysis, consistent with their taxonomic sections, species and genome types. A. villosa and A. batizocoi were grouped with A. hypogaea, suggesting the close relationship between these two diploid wild species and the cultivated peanut. Considerable phenotypic variation in oil content was observed among different sections and species. Nine alleles were identified as associated with oil content based on association analysis, of these, three alleles were associated with higher oil content but were absent in the cultivated peanut. The results demonstrated that there is great

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. Seasonal patterns of aster leafhopper (Hemiptera: Cicadellidae) abundance and aster yellows phytoplasma infectivity in Wisconsin carrot fields.

    PubMed

    Frost, K E; Esker, P D; Van Haren, R; Kotolski, L; Groves, R L

    2013-06-01

    In Wisconsin, vegetable crops are threatened annually by the aster yellows phytoplasma (AYp), which is obligately transmitted by the aster leafhopper. Using a multiyear, multilocation data set, seasonal patterns of leafhopper abundance and infectivity were modeled. A seasonal aster yellows index (AYI) was deduced from the model abundance and infectivity predictions to represent the expected seasonal risk of pathogen transmission by infectious aster leafhoppers. The primary goal of this study was to identify periods of time during the growing season when crop protection practices could be targeted to reduce the risk of AYp spread. Based on abundance and infectivity, the annual exposure of the carrot crop to infectious leafhoppers varied by 16- and 70-fold, respectively. Together, this corresponded to an estimated 1,000-fold difference in exposure to infectious leafhoppers. Within a season, exposure of the crop to infectious aster leafhoppers (Macrosteles quadrilineatus Forbes), varied threefold because of abundance and ninefold because of infectivity. Periods of above average aster leafhopper abundance occurred between 11 June and 2 August and above average infectivity occurred between 27 May and 13 July. A more comprehensive description of the temporal trends of aster leafhopper abundance and infectivity provides new information defining when the aster leafhopper moves into susceptible crop fields and when they transmit the pathogen to susceptible crops.

  10. 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

  11. Quality indexing with computer-aided lexicography

    NASA Technical Reports Server (NTRS)

    Buchan, Ronald L.

    1992-01-01

    Indexing with computers is a far cry from indexing with the first indexing tool, the manual card sorter. With the aid of computer-aided lexicography, both indexing and indexing tools can provide standardization, consistency, and accuracy, resulting in greater quality control than ever before. A brief survey of computer activity in indexing is presented with detailed illustrations from NASA activity. Applications from techniques mentioned, such as Retrospective Indexing (RI), can be made to many indexing systems. In addition to improving the quality of indexing with computers, the improved efficiency with which certain tasks can be done is demonstrated.

  12. Refinement, validation, and application of a benthic condition index for northern Gulf of Mexico estuaries

    USGS Publications Warehouse

    Engle, V.D.; Summers, J.K.

    1999-01-01

    By applying discriminant analysis to benthic macroinvertebrate data, we have developed an indicator of benthic condition for northern Gulf of Mexico estuaries. The data used were collected by the United States Environmental Protection Agency's Environmental Monitoring and Assessment Program (EMAP) in the Louisianian Province from 1991 to 1994. This benthic index represents a linear combination of the following weighted parameters: the proportion of expected species diversity, the mean abundance of tubificid oligochaetes, the percent of total abundance represented by capitellid polychaetes, the percent of total abundance represented by bivalve mollusks, and the percent of total abundance represented by amphipods. We successfully validated and retrospectively applied the benthic index to all of the benthic data collected by EMAP in the Louisianian Province. This benthic index was also calculated for independent data collected from Pensacola Bay, Florida, in order to demonstrate its flexibility and applicability to different estuarine systems within the same biogeographic region. The benthic index is a useful and valid indicator of estuarine condition that is intended to provide environmental managers with a simple tool for assessing the health of benthic macroinvertebrate communities.

  13. USE OF PERIPHYTON ASSEMBLAGE DATA AS AN INDEX OF BIOTIC INTEGRITY

    EPA Science Inventory

    Periphyton assemblages data collected from 233 stream site-visits (49 in 1993, 56 in 1994, and 128 in 1995) throughout the Mid-Appalachian region were used to develop a periphyton index of biotic integrity (PIBI} based on 1) algal genera richness; 2)the relative abundances of dia...

  14. Do abundance distributions and species aggregation correctly predict macroecological biodiversity patterns in tropical forests?

    PubMed Central

    Wiegand, Thorsten; Lehmann, Sebastian; Huth, Andreas; Fortin, Marie‐Josée

    2016-01-01

    Abstract Aim It has been recently suggested that different ‘unified theories of biodiversity and biogeography’ can be characterized by three common ‘minimal sufficient rules’: (1) species abundance distributions follow a hollow curve, (2) species show intraspecific aggregation, and (3) species are independently placed with respect to other species. Here, we translate these qualitative rules into a quantitative framework and assess if these minimal rules are indeed sufficient to predict multiple macroecological biodiversity patterns simultaneously. Location Tropical forest plots in Barro Colorado Island (BCI), Panama, and in Sinharaja, Sri Lanka. Methods We assess the predictive power of the three rules using dynamic and spatial simulation models in combination with census data from the two forest plots. We use two different versions of the model: (1) a neutral model and (2) an extended model that allowed for species differences in dispersal distances. In a first step we derive model parameterizations that correctly represent the three minimal rules (i.e. the model quantitatively matches the observed species abundance distribution and the distribution of intraspecific aggregation). In a second step we applied the parameterized models to predict four additional spatial biodiversity patterns. Results Species‐specific dispersal was needed to quantitatively fulfil the three minimal rules. The model with species‐specific dispersal correctly predicted the species–area relationship, but failed to predict the distance decay, the relationship between species abundances and aggregations, and the distribution of a spatial co‐occurrence index of all abundant species pairs. These results were consistent over the two forest plots. Main conclusions The three ‘minimal sufficient’ rules only provide an incomplete approximation of the stochastic spatial geometry of biodiversity in tropical forests. The assumption of independent interspecific placements is most

  15. Distribution and abundance of predators that affect duck production--prairie pothole region

    USGS Publications Warehouse

    Sargeant, A.B.; Greenwood, R.J.; Sovada, M.A.; Shaffer, T.L.

    1993-01-01

    During 1983-88, the relative abundance of 18 species and species-groups of mammalian and avian predators affecting duck production in the prairie pothole region was determined in 33 widely scattered study areas ranging in size from 23-26 km2. Accounts of each studied species and species-group include habitat and history, population structure and reported densities, and information on distribution and abundance from the present study. Index values of undetected, scarce, uncommon, common, or numerous were used to rate abundance of nearly all species in each study area. Principal survey methods were livetrapping of striped skunks (Mephitis mephitis) and Franklin's ground squirrels (Spermophilus franklinii), systematic searches for carnivore tracks in quarter sections (0.65 km2), daily records of sightings of individual predator species, and systematic searches for occupied nests of tree-nesting avian predators. Abundances of predators in individual areas were studied 1-3 years.The distribution and abundance of predator species throughout the prairie pothole region have undergone continual change since settlement of the region by Europeans in the late 1800's. Predator populations in areas we studied differed markedly from those of pristine times. The changes occurred from habitat alterations, human-inflicted mortality of predators, and interspecific relations among predator species. Indices from surveys of tracks revealed a decline in the abundance of red foxes (Vulpes vulpes) and an albeit less consistent decline in the abundance of raccoons (Procyon lotor) with an increase in the abundance of coyotes (Canis latrans). Records of locations of occupied nests revealed great horned owls (Bubo virginianus) and red-tailed hawks (Buteo jamaicensis) tended to nest 0.5 km apart, and American crows (Corvus brachyrhynchos) tended to avoid nesting 0.5 km of nests of red-tailed hawks. Excluding large gulls, for which no measurements of abundance were obtained, the number of

  16. 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.

  17. 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).

  18. 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.

  19. 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.

  20. [Seasonal evaluation of mammal species richness and abundance in the "Mário Viana" municipal reserve, Mato Grosso, Brasil].

    PubMed

    Rocha, Ednaldo Cândido; Silva, Elias; Martins, Sebastião Venâncio; Barreto, Francisco Cândido Cardoso

    2006-09-01

    We evaluated seasonal species presence and richness, and abundance of medium and large sized mammalian terrestrial fauna in the "Mário Viana" Municipal Biological Reserve, Nova Xavantina, Mato Grosso, Brazil. During 2001, two monthly visits were made to an established transect, 2,820 m in length. Records of 22 mammal species were obtained and individual footprint sequences quantified for seasonal calculation of species richness and relative abundance index (x footprints/km traveled). All 22 species occurred during the rainy season, but only 18 during the dry season. Pseudalopex vetulus (Lund, 1842) (hoary fox), Eira barbara (Linnaeus, 1758) (tayra), Puma concolor (Linnaeus, 1771) (cougar) and Hydrochaeris hydrochaeris (Linnaeus, 1766) (capybara) were only registered during the rainy season. The species diversity estimated using the Jackknife procedure in the dry season (19.83, CI = 2.73) was smaller than in the rainy season (25.67, CI = 3.43). Among the 18 species common in the two seasons, only four presented significantly different abundance indexes: Dasypus novemcinctus Linnaeus, 1758 (nine-banded armadillo), Euphractus sexcinctus (Linnaeus, 1758) (six-banded armadillo), Dasyprocta azarae Lichtenstein, 1823 (Azara's Agouti) and Tapirus terrestris (Linnaeus, 1758) (tapir). On the other hand, Priodontes maximus (Kerr, 1792) (giant armadillo) and Leopardus pardalis (Linnaeus, 1758) (ocelot) had identical abundance index over the two seasons. Distribution of species abundance in the sampled area followed the expected pattern for communities in equilibrium, especially in the rainy season, suggesting that the environment still maintains good characteristics for mammal conservation. The present study shows that the reserve, although only 470 ha in size, plays an important role for conservation of mastofauna of the area as a refuge in an environment full of anthropic influence (mainly cattle breeding in exotic pasture).

  1. 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.

  2. 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.

  3. 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

  4. Relations between fish abundances, summer temperatures, and forest harvest in a northern Minnesota stream system from 1997 to 2007

    USGS Publications Warehouse

    Merten, Eric C.; Hemstad, Nathaniel A.; Eggert, S.L.; Johnson, L.B.; Kolka, Randall K.; Newman, Raymond M.; Vondracek, Bruce C.

    2010-01-01

    Short-term effects of forest harvest on fish habitat have been well documented, including sediment inputs, leaf litter reductions, and stream warming. However, few studies have considered changes in local climate when examining postlogging changes in fish communities. To address this need, we examined fish abundances between 1997 and 2007 in a basin in a northern hardwood forest. Streams in the basin were subjected to experimental riparian forest harvest in fall 1997. We noted a significant decrease for fish index of biotic integrity and abundance of Salvelinus fontinalis and Phoxinus eos over the study period. However, for P. eos and Culaea inconstans, the temporal patterns in abundances were related more to summer air temperatures than to fine sediment or spring precipitation when examined using multiple regressions. Univariate regressions suggested that summer air temperatures influenced temporal patterns in fish communities more than fine sediment or spring precipitation.

  5. Relations between fish abundances, summer temperatures, and forest harvest in a northern Minnesota stream system from 1997 to 2007

    USGS Publications Warehouse

    Merten, Eric C.; Hemstad, Nathaniel A.; Eggert, L.S.; Johnson, L.B.; Kolka, R.K.; Newman, Raymond M.; Vondracek, Bruce C.

    2015-01-01

    Short-term effects of forest harvest on fish habitat have been well documented, including sediment inputs, leaf litter reductions, and stream warming. However, few studies have considered changes in local climate when examining postlogging changes in fish communities. To address this need, we examined fish abundances between 1997 and 2007 in a basin in a northern hardwood forest. Streams in the basin were subjected to experimental riparian forest harvest in fall 1997. We noted a significant decrease for fish index of biotic integrity and abundance of Salvelinus fontinalis and Phoxinus eos over the study period. However, for P. eos and Culaea inconstans, the temporal patterns in abundances were related more to summer air temperatures than to fine sediment or spring precipitation when examined using multiple regressions. Univariate regressions suggested that summer air temperatures influenced temporal patterns in fish communities more than fine sediment or spring precipitation.

  6. Effective indexing for face recognition

    NASA Astrophysics Data System (ADS)

    Sochenkov, I.; Sochenkova, A.; Vokhmintsev, A.; Makovetskii, A.; Melnikov, A.

    2016-09-01

    Face recognition is one of the most important tasks in computer vision and pattern recognition. Face recognition is useful for security systems to provide safety. In some situations it is necessary to identify the person among many others. In this case this work presents new approach in data indexing, which provides fast retrieval in big image collections. Data indexing in this research consists of five steps. First, we detect the area containing face, second we align face, and then we detect areas containing eyes and eyebrows, nose, mouth. After that we find key points of each area using different descriptors and finally index these descriptors with help of quantization procedure. The experimental analysis of this method is performed. This paper shows that performing method has results at the level of state-of-the-art face recognition methods, but it is also gives results fast that is important for the systems that provide safety.

  7. Thesaurus-Based Automatic Indexing: A Study of Indexing Failure.

    ERIC Educational Resources Information Center

    Caplan, Priscilla Louise

    This study examines automatic indexing performed with a manually constructed thesaurus on a document collection of titles and abstracts of library science master's papers. Errors are identified when the meaning of a posted descriptor, as identified by context in the thesaurus, does not match that of the passage of text which occasioned the…

  8. Indexes to Nuclear Regulatory Commission Issuances

    SciTech Connect

    1996-12-31

    Digests and indexes for issuances of the Commission (CLI), the Atomic Safety and licensing Board Panel (LBP), the Administrative Law Judges (ALJ) the Directors` Decisions (DD), and the Decisions on Petitions for Rulemaking (DPRM) are presented in this document. These digests and indexes are intended to serve as a guide to the issuances. Information elements are displayed in one or more of five separate formats arranged as follows: Case Name Index; Headers and Digests; Legal Citations Index; Subject Index; and Facility Index.

  9. Reflection based Extraordinary Optical Transmission Fiber Optic Probe for Refractive Index Sensing.

    PubMed

    Lan, Xinwei; Cheng, Baokai; Yang, Qingbo; Huang, Jie; Wang, Hanzheng; Ma, Yinfa; Shi, Honglan; Xiao, Hai

    2014-03-31

    Fiber optic probes for chemical sensing based on the extraordinary optical transmission (EOT) phenomenon are designed and fabricated by perforating subwavelength hole arrays on the gold film coated optical fiber endface. The device exhibits a red shift in response to the surrounding refractive index increases with high sensitivity, enabling a reflection-based refractive index sensor with a compact and simple configuration. By choosing the period of hole arrays, the sensor can be designed to operate in the near infrared telecommunication wavelength range, where the abundant source and detectors are available for easy instrumentation. The new sensor probe is demonstrated for refractive index measurement using refractive index matching fluids. The sensitivity reaches 573 nm/RIU in the 1.333~1.430 refractive index range.

  10. Habitat Suitability Index Models: Marten

    USGS Publications Warehouse

    Allen, Arthur W.

    1982-01-01

    Habitat preferences and species characteristics of the pine marten (Martes americana) are described in this publication. It is one of a series of Habitat Suitability Index (HSI) models and was developed through an analysis of available scientific data on the species-habitat requirements of the pine marten. Habitat use information is presented in a review of the literature, followed by the development of a HSI model. The model is presented in three formats: graphic, word and mathematical. Suitability index graphs quantify the species-habitat relationship. These data are then synthesized into a model which is designed to provide information for use in impact assessment and habitat management activities.

  11. Effects of transgenic cry1Ie maize on non-lepidopteran pest abundance, diversity and community composition.

    PubMed

    Guo, Jingfei; He, Kanglai; Bai, Shuxiong; Zhang, Tiantao; Liu, Yunjun; Wang, Fuxin; Wang, Zhenying

    2016-12-01

    Non-lepidopteran pests are exposed to, and may be influenced by, Bt toxins when feeding on Bt maize that express insecticidal Cry proteins derived from Bacillus thuringiensis (Bt). In order to assess the potential effects of transgenic cry1Ie maize on non-lepidopteran pest species and ecological communities, a 2-year field study was conducted to compare the non-lepidopteran pest abundance, diversity and community composition between transgenic cry1Ie maize (Event IE09S034, Bt maize) and its near isoline (Zong 31, non-Bt maize) by whole plant inspections. Results showed that Bt maize had no effects on non-lepidopteran pest abundance and diversity (Shannon-Wiener diversity index, Simpson's diversity index, species richness, and Pielou's index). There was a significant effect of year and sampling time on those indices analyzed. Redundancy analysis indicated maize type, sampling time and year totally explained 20.43 % of the variance in the non-lepidopteran pest community composition, but no association was presented between maize type (Bt maize and non-Bt maize) and the variance. Nonmetric multidimensional scaling analysis showed that sampling time and year, rather than maize type had close relationship with the non-lepidopteran pest community composition. These results corroborated the hypothesis that, at least in the short-term, the transgenic cry1Ie maize had negligible effects on the non-lepidopteran pest abundance, diversity and community composition.

  12. 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).

  13. 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

  14. 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

  15. The diversity and abundance of North American bird assemblages fail to track changing productivity.

    PubMed

    Dobson, LuAnna L; La Sorte, Frank A; Manne, Lisa L; Hawkins, Bradford A

    2015-04-01

    Plant biomass or productivity and the species richness of birds are associated across a range of spatial scales. Species-energy theory is generally assumed to explain these correlations. If true, bird richness should also track productivity temporally, and there should be spatial and temporal relationships between productivity and both bird abundance and bird richness. Using the summer normalized difference vegetation index (NDVI) for 1982-2006 and the North American Breeding Bird Survey, we evaluated the response of avian richness and abundance to interannual changes in plant biomass or productivity. We found positive spatial relationships between richness and NDVI for all 25 years. Temporally, however, richness and NDVI were positively associated at 1579 survey sites and negatively associated at 1627 sites (mean r2 = 0.09). Further, total abundance and NDVI were unrelated spatially (r2 values spanning < 0.01 and 0.03) and weakly related temporally (mean r2 = 0.10). We found no evidence that productivity drives bird richness beyond the spatial correlations, and neither prediction arising from species-energy theory was confirmed. Spatial relationships between productivity and bird richness may thus be largely spurious, arising via covariance between plant biomass or productivity and vegetation structural complexity, and the latter may be driving bird communities. This is consistent with the MacArthurs' classic hypothesis that the vertical profile of foliage drives bird species diversity.

  16. Diatom Abundance in Surface Sediments: A Quantitative Proxy for Primary Productivity at the Global Level?

    NASA Astrophysics Data System (ADS)

    Abrantes, F. F. G.; Lopes, C.; Romero, O. E.; Matos, L.; Rufino, M. M.; Magalhaes, V. H.; Cermeno, P.

    2014-12-01

    Diatom abundance and assemblage composition has for long been considered one of the best proxies for primary production, in particular for low latitude coastal upwelling areas, where they constitute the dominant phytoplankton. To investigate productivity conditions at those upwelling systems at any time and at the global level would be of great use for C export estimations and climate modeling, since primary production and C export in those systems is of major importance in controlling Earth's climate. To assess the value of the diatom sediment record at the global level, total abundance of marine diatoms was determined for 730 sites distributed by the five most important coastal upwelling systems of the modern ocean, and compared to several meaningful ecological parameters. Investigations of the satellite estimated primary productivity; upwelling index; water column physical properties and nutrient content, reveal a clear relation between sediment diatom abundance and primary production - although different between areas. Furthermore, upwelled waters [Si] appear as a determinant factor of the observed global diatom distribution.

  17. Mg, Al, Si, Ca, Ti, Fe, and Ni abundance for a sample of solar analogues

    NASA Astrophysics Data System (ADS)

    López-Valdivia, Ricardo; Bertone, Emanuele; Chávez, Miguel

    2017-01-01

    We report on the determination of chemical abundances of 38 solar analogues, including 11 objects previously identified as super metal-rich stars. We have measured the equivalent widths for 34 lines of 7 different chemical elements (Mg, Al, Si, Ca, Ti, Fe, and Ni) in high-resolution (R ˜ 80 000) spectroscopic images, obtained at the Observatorio Astrofísico Guillermo Haro (Sonora, Mexico), with the Cananea High-resolution Spectrograph. We derived chemical abundances using ATLAS12 model atmospheres and the Fortran code MOOG. We confirmed the super metallicity status of 6 solar analogues. Within our sample, BD+60 600 is the most metal-rich star ([Fe/H]=+0.35 dex), while for HD 166991 we obtained the lowest iron abundance ([Fe/H]=-0.53 dex). We also computed the so-called [Ref] index for 25 of our solar analogues, and we found, that BD+60 600 ([Ref]=+0.42) and BD+28 3198 ([Ref]=+0.34) are good targets for exoplanet search.

  18. Ohio's Competency Analysis Profile. Index.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This index contains the unit titles from all 60 Ohio's Competency Analysis Profile (OCAP) lists. It is intended to facilitate the combination of units from different OCAPs in order to develop curricula that meet specific program needs (e.g., learner differences, labor market demands, and technological developments). OCAP titles are as follows:…

  19. A Glossary of Indexing Terms.

    ERIC Educational Resources Information Center

    Buchanan, Brian

    An expansion of a list developed at a British library school, this glossary contains terminology used in indexing work done by libraries and information scientists. Entries are arranged alphabetically and vary in length from one line to one page. There may be up to three parts in each entry. The first is a basic definition with examples where…

  20. Teaching Physiology with Citation Index

    ERIC Educational Resources Information Center

    Klemm, W. R.

    1976-01-01

    Explains use of the Citation Index in writing term papers by assigning an older publication as a starting point in a literature search. By reading the original research report and following its subsequent use by other researchers, the student discovers the impact of the original research. (CS)

  1. Index of Spectrum Signature Data

    DTIC Science & Technology

    1985-05-01

    Frederick Research Corporation. Alexandria. VA 163 AN/APG-030 Radar Receiver Heasureaents Electromagnetic Coapatibilitv Analysis Center, US Navv Marine ... Electromagnetic Compatibility Characteristics of the W 86 Gun Fire Control Svstem. Naval HEapons Lab, Dahlgren, VA 501 Partial Spectrum Signature...ECAC-I-IO-(SS) DEPARTMENT OF DEFENSE Electromagnetic Compatibility Analysis Center Annapolis, Maryland 21402 INDEX OF SPECTRUM SIGNATURE DATA

  2. An ESL Index of Development.

    ERIC Educational Resources Information Center

    Larsen-Freeman, Diane

    1978-01-01

    Reports on the progress being made in an attempt to establish a second language acquisition index of development that would gauge a learner's second language proficiency. A project was undertaken involving the analysis of 212 compositions written by university students of English as a second language. (CFM)

  3. Refractive Index Enhancement in Gases

    DTIC Science & Technology

    2012-02-29

    experimentally demonstrated the key ingredients of this approach in Rubidium vapor where we have observe enhanced refractive index with vanishing absorption...beam, Ep. We have recently experimentally demonstrated this effect in a 1-mm-long Rubidium (Rb) vapor cell at high vapor densities. Here, we utilize

  4. Competency Index. [Health Technology Cluster.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This competency index lists the competencies included in the 62 units of the Tech Prep Competency Profiles within the Health Technologies Cluster. The unit topics are as follows: employability skills; professionalism; teamwork; computer literacy; documentation; infection control and risk management; medical terminology; anatomy, physiology, and…

  5. 1988 Bulletin compilation and index

    SciTech Connect

    1989-02-01

    This document is published to provide current information about the national program for managing spent fuel and high-level radioactive waste. This document is a compilation of issues from the 1988 calendar year. A table of contents and one index have been provided to assist in finding information.

  6. USGS 1-min Dst index

    USGS Publications Warehouse

    Gannon, J.L.; Love, J.J.

    2011-01-01

    We produce a 1-min time resolution storm-time disturbance index, the USGS Dst, called Dst8507-4SM. This index is based on minute resolution horizontal magnetic field intensity from low-latitude observatories in Honolulu, Kakioka, San Juan and Hermanus, for the years 1985-2007. The method used to produce the index uses a combination of time- and frequency-domain techniques, which more clearly identifies and excises solar-quiet variation from the horizontal intensity time series of an individual station than the strictly time-domain method used in the Kyoto Dst index. The USGS 1-min Dst is compared against the Kyoto Dst, Kyoto Sym-H, and the USGS 1-h Dst (Dst5807-4SH). In a time series comparison, Sym-H is found to produce more extreme values during both sudden impulses and main phase maximum deviation, possibly due to the latitude of its contributing observatories. Both Kyoto indices are shown to have a peak in their distributions below zero, while the USGS indices have a peak near zero. The USGS 1-min Dst is shown to have the higher time resolution benefits of Sym-H, while using the more typical low-latitude observatories of Kyoto Dst. ?? 2010.

  7. Index and Description of Tests.

    ERIC Educational Resources Information Center

    New York Univ., NY. Inst. for Developmental Studies.

    The tests described in this index are used by the Institute for Developmental Studies in its principal areas of research and do not include recently developed tests. The research at the Institute is concerned with (1) the relationship of differing environments to language development, (2) classroom communication between teachers and children of…

  8. Mining and Indexing Graph Databases

    ERIC Educational Resources Information Center

    Yuan, Dayu

    2013-01-01

    Graphs are widely used to model structures and relationships of objects in various scientific and commercial fields. Chemical molecules, proteins, malware system-call dependencies and three-dimensional mechanical parts are all modeled as graphs. In this dissertation, we propose to mine and index those graph data to enable fast and scalable search.…

  9. Coming to Schools: Creativity Indexes

    ERIC Educational Resources Information Center

    Robelen, Erik W.

    2012-01-01

    At a time when U.S. political and business leaders are raising concerns about the need to better nurture creativity and innovative thinking among young people, several states are exploring the development of an index that would gauge the extent to which schools provide opportunities to foster those qualities. In Massachusetts, a new state…

  10. Future of gradient index optics

    NASA Astrophysics Data System (ADS)

    Hashizume, Hideki; Hamanaka, Kenjiro; Graham, Alan C., III; Zhu, X. Frank

    2001-11-01

    First developed over 30 years ago, gradient index lenses play an important role not only in telecommunications technology, but also in applications such as information interface and biomedical technology. Traditional manufacturing consists of doping a certain ion, A+ into the mother glass, drawing the glass into rods and then immersing the rods into s molten salt bath containing another certain ion B+. During a thermal ion exchange process, the original ion migrates out of the mother glass, and is replaced by the alternate ion, creating a refractive index variation. Current research is being conducted to improve the thermal ion exchange technology, and open new applications. This research includes extending working distances to greater than 100mm, decreasing the lens diameter, increasing the effective radius, and combining the technology with other technologies such as photolithographically etched masks to produce arrays of gradient index lenses. As a result of this ongoing research, the gradient index lens is expected to continue to be the enabling optical technology in the first decade of the new millennium and beyond.

  11. National hospital input price index.

    PubMed

    Freeland, M S; Anderson, G; Schendler, C E

    1979-01-01

    The national community hospital input price index presented here isolates the effects of prices of goods and services required to produce hospital care and measures the average percent change in prices for a fixed market basket of hospital inputs. Using the methodology described in this article, weights for various expenditure categories were estimated and proxy price variables associated with each were selected. The index is calculated for the historical period 1970 through 1978 and forecast for 1979 through 1981. During the historical period, the input price index increased an average of 8.0 percent a year, compared with an average rate of increase of 6.6 percent for overall consumer prices. For the period 1979 through 1981, the average annual increase is forecast at between 8.5 and 9.0 per cent. Using the index to deflate growth in expenses, the level of real growth in expenditures per inpatient day (net service intensity growth) averaged 4.5 percent per year with considerable annual variation related to government and hospital industry policies.

  12. Witten index for noncompact dynamics

    NASA Astrophysics Data System (ADS)

    Lee, Seung-Joo; Yi, Piljin

    2016-06-01

    Among gauged dynamics motivated by string theory, we find many with gapless asymptotic directions. Although the natural boundary condition for ground states is L 2, one often turns on chemical potentials or supersymmetric mass terms to regulate the infrared issues, instead, and computes the twisted partition function. We point out how this procedure generically fails to capture physical L 2 Witten index with often misleading results. We also explore how, nevertheless, the Witten index is sometimes intricately embedded in such twisted partition functions. For d = 1 theories with gapless continuum sector from gauge multiplets, such as non-primitive quivers and pure Yang-Mills, a further subtlety exists, leading to fractional expressions. Quite unexpectedly, however, the integral L 2 Witten index can be extracted directly and easily from the twisted partition function of such theories. This phenomenon is tied to the notion of the rational invariant that appears naturally in the wall-crossing formulae, and offers a general mechanism of reading off Witten index directly from the twisted partition function. Along the way, we correct early numerical results for some of mathcal{N} = 4 , 8 , 16 pure Yang-Mills quantum mechanics, and count threshold bound states for general gauge groups beyond SU( N ).

  13. A hierarchical spatial model of avian abundance with application to Cerulean Warblers

    USGS Publications Warehouse

    Thogmartin, Wayne E.; Sauer, John R.; Knutson, Melinda G.

    2004-01-01

    Surveys collecting count data are the primary means by which abundance is indexed for birds. These counts are confounded, however, by nuisance effects including observer effects and spatial correlation between counts. Current methods poorly accommodate both observer and spatial effects because modeling these spatially autocorrelated counts within a hierarchical framework is not practical using standard statistical approaches. We propose a Bayesian approach to this problem and provide as an example of its implementation a spatial model of predicted abundance for the Cerulean Warbler (Dendroica cerulea) in the Prairie-Hardwood Transition of the upper midwestern United States. We used an overdispersed Poisson regression with fixed and random effects, fitted by Markov chain Monte Carlo methods. We used 21 years of North American Breeding Bird Survey counts as the response in a loglinear function of explanatory variables describing habitat, spatial relatedness, year effects, and observer effects. The model included a conditional autoregressive term representing potential correlation between adjacent route counts. Categories of explanatory habitat variables in the model included land cover composition and configuration, climate, terrain heterogeneity, and human influence. The inherent hierarchy in the model was from counts occurring, in part, as a function of observers within survey routes within years. We found that the percentage of forested wetlands, an index of wetness potential, and an interaction between mean annual precipitation and deciduous forest patch size best described Cerulean Warbler abundance. Based on a map of relative abundance derived from the posterior parameter estimates, we estimated that only 15% of the species' population occurred on federal land, necessitating active engagement of public landowners and state agencies in the conservation of the breeding habitat for this species. Models of this type can be applied to any data in which the response

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. The impact of rare taxa on a fish index of biotic integrity

    USGS Publications Warehouse

    Wan, H.; Chizinski, C.J.; Dolph, C.L.; Vondracek, B.; Wilson, B.N.

    2010-01-01

    The index of biotic integrity (IBI) is a commonly used bioassessment tool that integrates abundance and richness measures to assess water quality. In developing IBIs that are both responsive to human disturbance and resistant to natural variability and sampling error, water managers must decide how to weigh information about rare and abundant taxa, which in turn requires an understanding of the sensitivity of indices to rare taxa. Herein, we investigated the influence of rare fish taxa (within the lower 5% of rank abundance curves) on IBI metric and total scores for stream sites in two of Minnesota's major river basins, the St. Croix (n = 293 site visits) and Upper Mississippi (n = 210 site visits). We artificially removed rare taxa from biological samples by (1) separately excluding each individual taxon that fell within the lower 5% of rank abundance curves; (2) simultaneously excluding all taxa that had an abundance of one (singletons) or two (doubletons); and (3) simultaneously excluding all taxa that fell within the lower 5% of rank abundance curves. We then compared IBI metric and total scores before and after removal of rare taxa using the normalized root mean square error (nRMSE) and regression analysis. The difference in IBI metric and total scores increased as more taxa were removed. Moreover, when multiple rare taxa were removed, the nRMSE was related to sample abundance and to total taxa richness, with greater nRMSE observed in samples with a larger number of taxa or sample abundance. Metrics based on relative abundance of fish taxa were less sensitive to the loss of rare taxa, whereas those based on taxa richness were more sensitive, because taxa richness metrics give more weight to rare taxa compared to the relative abundance metrics. ?? 2010 Elsevier Ltd.

  5. 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.

  6. 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.

  7. Indexing and Retrieval for the Web.

    ERIC Educational Resources Information Center

    Rasmussen, Edie M.

    2003-01-01

    Explores current research on indexing and ranking as retrieval functions of search engines on the Web. Highlights include measuring search engine stability; evaluation of Web indexing and retrieval; Web crawlers; hyperlinks for indexing and ranking; ranking for metasearch; document structure; citation indexing; relevance; query evaluation;…

  8. On the age-independent publication index.

    PubMed

    Sangwal, Keshra

    2012-06-01

    It is shown that the age-independent index based on h-type index per decade, called hereafter an α index instead of the a index, suggested by Kosmulski (Journal of Informetrics 3, 341-347, 2009) and Abt (Scientometrics 2012) is related to the square-root of the ratio of citation acceleration a to the Hirsch constant A.

  9. 13 CFR 102.9 - Public Index.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Public Index. 102.9 Section 102.9... Information § 102.9 Public Index. (a) The Public Index is a document that provides identifying information... FOIA, that periodic publication and distribution of the Public Index is unnecessary and...

  10. 32 CFR 701.39 - Vaughn index.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 5 2011-07-01 2011-07-01 false Vaughn index. 701.39 Section 701.39 National... DOCUMENTS AFFECTING THE PUBLIC FOIA Definitions and Terms § 701.39 Vaughn index. Itemized index, correlating... agency's nondisclosure justification. The index may contain such information as: date of...

  11. 32 CFR 701.39 - Vaughn index.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Vaughn index. 701.39 Section 701.39 National... DOCUMENTS AFFECTING THE PUBLIC FOIA Definitions and Terms § 701.39 Vaughn index. Itemized index, correlating... agency's nondisclosure justification. The index may contain such information as: date of...

  12. 36 CFR 200.5 - Indexes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Indexes. 200.5 Section 200.5..., AND PROCEDURES Functions and Procedures § 200.5 Indexes. Publication of the indexes described in § 200.... However, copies of the indexes are available for public review in the Forest Service headquarters...

  13. 36 CFR 200.5 - Indexes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Indexes. 200.5 Section 200.5..., AND PROCEDURES Functions and Procedures § 200.5 Indexes. Publication of the indexes described in § 200.... However, copies of the indexes are available for public review in the Forest Service headquarters...

  14. 13 CFR 102.9 - Public Index.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Public Index. 102.9 Section 102.9... Information § 102.9 Public Index. (a) The Public Index is a document that provides identifying information... FOIA, that periodic publication and distribution of the Public Index is unnecessary and...

  15. 40 CFR 58.50 - Index reporting.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Index reporting. 58.50 Section 58.50... QUALITY SURVEILLANCE Air Quality Index Reporting § 58.50 Index reporting. (a) The State or where... quality index that complies with the requirements of appendix G to this part. (b) Reporting is...

  16. 40 CFR 58.50 - Index reporting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Index reporting. 58.50 Section 58.50... QUALITY SURVEILLANCE Air Quality Index Reporting § 58.50 Index reporting. (a) The State or where... quality index that complies with the requirements of appendix G to this part. (b) Reporting is...

  17. Machine-Aided Indexing of Technical Literature

    ERIC Educational Resources Information Center

    Klingbiel, Paul H.

    1973-01-01

    To index at the Defense Documentation Center (DDC), an automated system must choose single words or phrases rapidly and economically. Automation of DDC's indexing has been machine-aided from its inception. A machine-aided indexing system is described that indexes one million words of text per hour of CPU time. (22 references) (Author/SJ)

  18. Development of indoor environmental index: Air quality index and thermal comfort index

    NASA Astrophysics Data System (ADS)

    Saad, S. M.; Shakaff, A. Y. M.; Saad, A. R. M.; Yusof, A. M.; Andrew, A. M.; Zakaria, A.; Adom, A. H.

    2017-03-01

    In this paper, index for indoor air quality (also known as IAQI) and thermal comfort index (TCI) have been developed. The IAQI was actually modified from previous outdoor air quality index (AQI) designed by the United States Environmental Protection Agency (US EPA). In order to measure the index, a real-time monitoring system to monitor indoor air quality level was developed. The proposed system consists of three parts: sensor module cloud, base station and service-oriented client. The sensor module cloud (SMC) contains collections of sensor modules that measures the air quality data and transmit the captured data to base station through wireless. Each sensor modules includes an integrated sensor array that can measure indoor air parameters like Carbon Dioxide, Carbon Monoxide, Ozone, Nitrogen Dioxide, Oxygen, Volatile Organic Compound and Particulate Matter. Temperature and humidity were also being measured in order to determine comfort condition in indoor environment. The result from several experiments show that the system is able to measure the air quality presented in IAQI and TCI in many indoor environment settings like air-conditioner, chemical present and cigarette smoke that may impact the air quality. It also shows that the air quality are changing dramatically, thus real-time monitoring system is essential.

  19. The Biodiversity Informatics Potential Index

    PubMed Central

    2011-01-01

    Background Biodiversity informatics is a relatively new discipline extending computer science in the context of biodiversity data, and its development to date has not been uniform throughout the world. Digitizing effort and capacity building are costly, and ways should be found to prioritize them rationally. The proposed 'Biodiversity Informatics Potential (BIP) Index' seeks to fulfill such a prioritization role. We propose that the potential for biodiversity informatics be assessed through three concepts: (a) the intrinsic biodiversity potential (the biological richness or ecological diversity) of a country; (b) the capacity of the country to generate biodiversity data records; and (c) the availability of technical infrastructure in a country for managing and publishing such records. Methods Broadly, the techniques used to construct the BIP Index were rank correlation, multiple regression analysis, principal components analysis and optimization by linear programming. We built the BIP Index by finding a parsimonious set of country-level human, economic and environmental variables that best predicted the availability of primary biodiversity data accessible through the Global Biodiversity Information Facility (GBIF) network, and constructing an optimized model with these variables. The model was then applied to all countries for which sufficient data existed, to obtain a score for each country. Countries were ranked according to that score. Results Many of the current GBIF participants ranked highly in the BIP Index, although some of them seemed not to have realized their biodiversity informatics potential. The BIP Index attributed low ranking to most non-participant countries; however, a few of them scored highly, suggesting that these would be high-return new participants if encouraged to contribute towards the GBIF mission of free and open access to biodiversity data. Conclusions The BIP Index could potentially help in (a) identifying countries most likely to

  20. RNDSI: A ratio normalized difference soil index for remote sensing of urban/suburban environments

    NASA Astrophysics Data System (ADS)

    Deng, Yingbin; Wu, Changshan; Li, Miao; Chen, Renrong

    2015-07-01

    Understanding land use land cover change (LULCC) is a prerequisite for urban planning and environment management. For LULCC studies in urban/suburban environments, the abundance and spatial distributions of bare soil are essential due to its biophysically different properties when compared to anthropologic materials. Soil, however, is very difficult to be identified using remote sensing technologies majorly due to its complex physical and chemical compositions, as well as the lack of a direct relationship between soil abundance and its spectral signatures. This paper presents an empirical approach to enhance soil information through developing the ratio normalized difference soil index (RNDSI). The first step involves the generation of random samples of three major land cover types, namely soil, impervious surface areas (ISAs), and vegetation. With spectral signatures of these samples, a normalized difference soil index (NDSI) was proposed using the combination of bands 7 and 2 of Landsat Thematic Mapper Image. Finally, a ratio index was developed to further highlight soil covers through dividing the NDSI by the first component of tasseled cap transformation (TC1). Qualitative (e.g., frequency histogram and box charts) and quantitative analyses (e.g., spectral discrimination index and classification accuracy) were adopted to examine the performance of the developed RNDSI. Analyses of results and comparative analyses with two other relevant indices, biophysical composition index (BCI) and enhanced built-up and bareness Index (EBBI), indicate that RNDSI is promising in separating soil from ISAs and vegetation, and can serve as an input to LULCC models.

  1. Quantification of nanoscale nuclear refractive index changes during the cell cycle

    NASA Astrophysics Data System (ADS)

    Bista, Rajan K.; Uttam, Shikhar; Wang, Pin; Staton, Kevin; Choi, Serah; Bakkenist, Christopher J.; Hartman, Douglas J.; Brand, Randall E.; Liu, Yang

    2011-07-01

    Intrigued by our recent finding that the nuclear refractive index is significantly increased in malignant cells and histologically normal cells in clinical histology specimens derived from cancer patients, we sought to identify potential biological mechanisms underlying the observed phenomena. The cell cycle is an ordered series of events that describes the intervals of cell growth, DNA replication, and mitosis that precede cell division. Since abnormal cell cycles and increased proliferation are characteristic of many human cancer cells, we hypothesized that the observed increase in nuclear refractive index could be related to an abundance or accumulation of cells derived from cancer patients at a specific point or phase(s) of the cell cycle. Here we show that changes in nuclear refractive index of fixed cells are seen as synchronized populations of cells that proceed through the cell cycle, and that increased nuclear refractive index is strongly correlated with increased DNA content. We therefore propose that an abundance of cells undergoing DNA replication and mitosis may explain the increase in nuclear refractive index observed in both malignant and histologically normal cells from cancer patients. Our findings suggest that nuclear refractive index may be a novel physical parameter for early cancer detection and risk stratification.

  2. A Benthic Community Index for streams in the Northern Lakes and Forests Ecoregion

    USGS Publications Warehouse

    Butcher, Jason T.; Stewart, Paul M.; Simon, Thomas P.

    2003-01-01

    Encompassing the northern glaciated section of the Midwest United States, the Northern Lakes and Forests Ecoregion is characterized by mixed conifer and deciduous forests and wetlands. Sites were randomly selected in the ecoregion using the Environmental Protection Agency's Environmental Monitoring and Assessment Program designed to develop an index of biotic integrity for wadeable streams. Macroinvertebrates were sampled during the fall of 1998 and 1999 using a multi-habitat, composite-sample method. Two hundred forty-six invertebrate taxa in 97 families were collected from 94 sites. Ten of 42 candidate metrics satisfied metric selection criteria, including six structural metrics (number of Ephemeroptera taxa, number of Diptera taxa, richness, Shannon-Wiener diversity, percent Trichoptera abundance, and percent Crustacea and Mollusca abundance), two functional metrics (number of Filterer taxa and number of Scraper taxa), and two conditional metrics (number of Ephemeroptera, Trichoptera, and Plecoptera taxa and Hilsenhoff Biotic Index). These metrics were used to develop a Benthic Community Index to assess the biological integrity of wadeable streams in the ecoregion. Index values ranged from 10 to 50, and scores from impaired sites were significantly different than non-impaired sites (P<0.001). Index values were divided into three narrative interpretations of biological integrity (poor, fair, and good). After further testing, the index may provide a useful biological assessment tool for resource managers in the ecoregion.

  3. [Composition, abundance and distribution of populations of commercially important gastropods in La Guajira, Colombian Caribbean].

    PubMed

    Nieto-Bernal, Ramón; Luis, Chasqui; Rodriguez, Angélica María; Castro, Erick; Gil-Agudelo, Diego L

    2013-06-01

    In the continental Colombian Caribbean the conch resource exploitation and the status of snails populations has been poorly studied, which are reflected in the lack of fisheries management. This study assesses composition, population density and distribution of the gastropods species that make conch resource in La Guajira region. Underwater visual censuses for snails were performed between September-November 2009 in 145100x4m (400m2) transects, spanning a total area of 56920m2 between Riohacha and Cabo de la Vela. The study was complemented with the evaluation of composition, abundance and size of gastropods conch found in the discarded-by-fishermen shell mounds in 13 beaches. In October 2010 another 40 transects were evaluated (16 000 m2) from the Southern of Riohacha to the Camarones village (La Guajira). We found a total of 9911 snails belonging to 12 species, the most abundant being Strombus pugilis with 8 912 individuals and an average density of 1 538.4 +/- 3 662.6 ind./ha, followed by Vasum muricatum with 374 individuals and an average density of 51.8 +/- 91.2 ind./ha. Calculating the importance value index (IVI) for both living organisms as the empty shells on beaches, shows that Turbinella angulata is the most used species by artisanal fishermen in the region. Cassis madagascariensis and Cassis tuberosa are also important snail resources in the region (as suggested by the number of empty shells found in beaches), but its densities were low. Strombus gigas, with only three living organisms found in the area, presented the lowest abundance ever found in the Colombian Caribbean (0.52 +/- 3.6 ind./ha), showing that queen conch population in La Guajira cannot support commercial exploitation. The abundance of discarded S. gigas shells on beaches suggests resource exploitation in the recent past. Results remarks the urgency of implementing management plans for snail fisheries in the region.

  4. CALCIUM AND LIGHT-ELEMENTS ABUNDANCE VARIATIONS FROM HIGH-RESOLUTION SPECTROSCOPY IN GLOBULAR CLUSTERS

    SciTech Connect

    Carretta, Eugenio; Bragaglia, Angela; Bellazzini, Michele; Gratton, Raffaele; Lucatello, Sara; D'Orazi, Valentina E-mail: angela.bragaglia@oabo.inaf.it E-mail: raffaele.gratton@oapd.inaf.it E-mail: valentina.dorazi@oapd.inaf.it

    2010-03-20

    We use abundances of Ca, O, Na, and Al from high-resolution UVES spectra of 200 red giants in 17 globular clusters (GCs) to investigate the correlation found by Lee et al. between chemical enrichment from SN II and star-to-star variations in light elements in GC stars. We find that (1) the [Ca/H] variations between first and second generation stars are tiny in most GCs ({approx}0.02-0.03 dex, comparable with typical observational errors). In addition, (2) using a large sample of red giants in M 4 with abundances from UVES spectra from Marino et al., we find that Ca and Fe abundances in the two populations of Na-poor and Na-rich stars are identical. These facts suggest that the separation seen in color-magnitude diagrams using the U band or hk index (as observed in NGC 1851 by Han et al.) are not due to Ca variations. Small differences in [Ca/H] as associated with hk variations might be due to a small systematic effect in abundance analysis, because most O-poor/Na-rich (He-rich) stars have slightly larger [Fe/H] (by 0.027 dex on average, due to decreased H in the ratio) than first generation stars and are then located at redder positions in the V, hk plane. While a few GCs (M 54, {omega} Cen, M 22, maybe even NGC 1851) do actually show various degree of metallicity spread, our findings eliminate the need of a close link between the enrichment by core-collapse supernovae with the mechanism responsible for the Na-O anticorrelation.

  5. Diatom species abundance and morphologically-based dissolution proxies in coastal Southern Ocean assemblages

    NASA Astrophysics Data System (ADS)

    Warnock, Jonathan P.; Scherer, Reed P.

    2015-07-01

    Taphonomic processes alter diatom assemblages in sediments, thus potentially negatively impacting paleoclimate records at various rates across space, time, and taxa. However, quantitative taphonomic data is rarely included in diatom-based paleoenvironmental reconstructions and no objective standard exists for comparing diatom dissolution in sediments recovered from marine depositional settings, including the Southern Ocean's opal belt. Furthermore, identifying changes to diatom dissolution through time can provide insight into the efficiency of both upper water column nutrient recycling and the biological pump. This is significant in that reactive metal proxies (e.g. Al, Ti) in the sediments only account for post-depositional dissolution, not the water column where the majority of dissolution occurs. In order to assess the range of variability of responses to dissolution in a typical Southern Ocean diatom community and provide a quantitative guideline for assessing taphonomic variability in diatoms recovered from core material, a sediment trap sample was subjected to controlled, serial dissolution. By evaluating dissolution-induced changes to diatom species' relative abundance, three preservational categories of diatoms have been identified: gracile, intermediate, and robust. The relative abundances of these categories can be used to establish a preservation grade for diatom assemblages. However, changes to the relative abundances of diatom species in sediment samples may reflect taphonomic or ecological factors. In order to address this complication, relative abundance changes have been tied to dissolution-induced morphological change to the areolae of Fragilariopsis curta, a significant sea-ice indicator in Southern Ocean sediments. This correlation allows differentiation between gracile species loss to dissolution versus ecological factors or sediment winnowing. These results mirror a similar morphological dissolution index from a parallel study utilizing

  6. The relative contribution of climate to changes in lesser prairie-chicken abundance

    USGS Publications Warehouse

    Ross, Beth E.; Haukos, David A.; Hagen, Christian A.; Pitman, James

    2016-01-01

    Managing for species using current weather patterns fails to incorporate the uncertainty associated with future climatic conditions; without incorporating potential changes in climate into conservation strategies, management and conservation efforts may fall short or waste valuable resources. Understanding the effects of climate change on species in the Great Plains of North America is especially important, as this region is projected to experience an increased magnitude of climate change. Of particular ecological and conservation interest is the lesser prairie-chicken (Tympanuchus pallidicinctus), which was listed as “threatened” under the U.S. Endangered Species Act in May 2014. We used Bayesian hierarchical models to quantify the effects of extreme climatic events (extreme values of the Palmer Drought Severity Index [PDSI]) relative to intermediate (changes in El Niño Southern Oscillation) and long-term climate variability (changes in the Pacific Decadal Oscillation) on trends in lesser prairie-chicken abundance from 1981 to 2014. Our results indicate that lesser prairie-chicken abundance on leks responded to environmental conditions of the year previous by positively responding to wet springs (high PDSI) and negatively to years with hot, dry summers (low PDSI), but had little response to variation in the El Niño Southern Oscillation and the Pacific Decadal Oscillation. Additionally, greater variation in abundance on leks was explained by variation in site relative to broad-scale climatic indices. Consequently, lesser prairie-chicken abundance on leks in Kansas is more strongly influenced by extreme drought events during summer than other climatic conditions, which may have negative consequences for the population as drought conditions intensify throughout the Great Plains.

  7. Calcium and Light-elements Abundance Variations from High-resolution Spectroscopy in Globular Clusters

    NASA Astrophysics Data System (ADS)

    Carretta, Eugenio; Bragaglia, Angela; Gratton, Raffaele; Lucatello, Sara; Bellazzini, Michele; D'Orazi, Valentina

    2010-03-01

    We use abundances of Ca, O, Na, and Al from high-resolution UVES spectra of 200 red giants in 17 globular clusters (GCs) to investigate the correlation found by Lee et al. between chemical enrichment from SN II and star-to-star variations in light elements in GC stars. We find that (1) the [Ca/H] variations between first and second generation stars are tiny in most GCs (~0.02-0.03 dex, comparable with typical observational errors). In addition, (2) using a large sample of red giants in M 4 with abundances from UVES spectra from Marino et al., we find that Ca and Fe abundances in the two populations of Na-poor and Na-rich stars are identical. These facts suggest that the separation seen in color-magnitude diagrams using the U band or hk index (as observed in NGC 1851 by Han et al.) are not due to Ca variations. Small differences in [Ca/H] as associated with hk variations might be due to a small systematic effect in abundance analysis, because most O-poor/Na-rich (He-rich) stars have slightly larger [Fe/H] (by 0.027 dex on average, due to decreased H in the ratio) than first generation stars and are then located at redder positions in the V, hk plane. While a few GCs (M 54, ω Cen, M 22, maybe even NGC 1851) do actually show various degree of metallicity spread, our findings eliminate the need of a close link between the enrichment by core-collapse supernovae with the mechanism responsible for the Na-O anticorrelation. Based on data collected at the European Southern Observatory, Chile, programmes 072.D-507, 073.D-0211, 072.D-0742, and 077.D-0182.

  8. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure.

    PubMed

    Roberson, Elizabeth J; Chips, Michael J; Carson, Walter P; Rooney, Thomas P

    2016-01-01

    Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7-12 times greater in deerfree plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread.

  9. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

    PubMed Central

    Chips, Michael J.; Carson, Walter P.

    2016-01-01

    Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7–12 times greater in deerfree plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread. PMID:27703868

  10. Liquefaction potential index: Field assessment

    USGS Publications Warehouse

    Toprak, S.; Holzer, T.L.

    2003-01-01

    Cone penetration test (CPT) soundings at historic liquefaction sites in California were used to evaluate the predictive capability of the liquefaction potential index (LPI), which was defined by Iwasaki et al. in 1978. LPI combines depth, thickness, and factor of safety of liquefiable material inferred from a CPT sounding into a single parameter. LPI data from the Monterey Bay region indicate that the probability of surface manifestations of liquefaction is 58 and 93%, respectively, when LPI equals or exceeds 5 and 15. LPI values also generally correlate with surface effects of liquefaction: Decreasing from a median of 12 for soundings in lateral spreads to 0 for soundings where no surface effects were reported. The index is particularly promising for probabilistic liquefaction hazard mapping where it may be a useful parameter for characterizing the liquefaction potential of geologic units.

  11. Reconstruction of Pacific salmon abundance from riparian tree-ring growth.

    PubMed

    Drake, D C; Naiman, Robert J

    2007-07-01

    We use relationships between modern Pacific salmon (Oncorhynchus spp.) escapement (migrating adults counted at weirs or dams) and riparian tree-ring growth to reconstruct the abundance of stream-spawning salmon over 150-350 years. After examining nine sites, we produced reconstructions for five mid-order rivers and four salmon species over a large geographic range in the Pacific Northwest: chinook (O. tschwatcha) in the Umpqua River, Oregon, USA; sockeye (O. nerka) in Drinkwater Creek, British Columbia, Canada; pink (O. gorbuscha) in Sashin Creek, southeastern Alaska, USA; chum (O. keta) in Disappearance Creek, southeastern Alaska, USA; and pink and chum in the Kadashan River, southeastern Alaska, USA. We first derived stand-level, non-climatic growth chronologies from riparian trees using standard dendroecology methods and differencing. When the chronologies were compared to 18-55 years of adult salmon escapement we detected positive, significant correlations at five of the nine sites. Regression models relating escapement to tree-ring growth at the five sites were applied to the differenced chronologies to reconstruct salmon abundance. Each reconstruction contains unique patterns characteristic of the site and salmon species. Reconstructions were validated by comparison to local histories (e.g., construction of dams and salmon canneries) and regional fisheries data such as salmon landings and aerial surveys and the Pacific Decadal Oscillation climate index. The reconstructions capture lower-frequency cycles better than extremes and are most useful for determination and comparison of relative abundance, cycles, and the effects of interventions. Reconstructions show lower population cycle maxima in both Umpqua River chinook and Sashin Creek pink salmon in recent decades. The Drinkwater Creek reconstruction suggests that sockeye abundance since the mid-1990s has been 15-25% higher than at any time since 1850, while no long-term deviations from natural cycles are

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. (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).

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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).

  3. 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.

  4. 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.

  5. Habitat Suitability Index Models: Pronghorn

    USGS Publications Warehouse

    Allen, Arthur W.; Cook, John G.; Armbruster, Michael J.

    1984-01-01

    This is one of a series of publications that provide information on the habitat requirements of selected fish and wildlife species. Literature describing the relationship between habitat variables related to life requisites and habitat suitability for the pronghorn (Antilocapra americana) are synthesized. These data are subsequently used to develop Habitat Suitability Index (HSI) models. The HSI models are designed to provide information that can be used in impact assessment and habitat management.

  6. Biomimetic Gradient Index (GRIN) Lenses

    DTIC Science & Technology

    2006-01-01

    optics include single lenses inspired by cephalopod (octopus) eyes and a three-lens, wide field of view, optical system for a surveillance sensor...camera. Details are easily resolv- able with the polymer lens. This lens system was installed on an Evolution unmanned aerial vehicle (UAV) with a...lens system was installed in an NRL Evolution UAV and used to record video images at a height of up to 1000 ft. The index gradients in the polymer

  7. The glycemic index: physiological significance.

    PubMed

    Esfahani, Amin; Wong, Julia M W; Mirrahimi, Arash; Srichaikul, Korbua; Jenkins, David J A; Kendall, Cyril W C

    2009-08-01

    The glycemic index (GI) is a physiological assessment of a food's carbohydrate content through its effect on postprandial blood glucose concentrations. Evidence from trials and observational studies suggests that this physiological classification may have relevance to those chronic Western diseases associated with overconsumption and inactivity leading to central obesity and insulin resistance. The glycemic index classification of foods has been used as a tool to assess potential prevention and treatment strategies for diseases where glycemic control is of importance, such as diabetes. Low GI diets have also been reported to improve the serum lipid profile, reduce C-reactive protein (CRP) concentrations, and aid in weight control. In cross-sectional studies, low GI or glycemic load diets (mean GI multiplied by total carbohydrate) have been associated with higher levels of high-density lipoprotein cholesterol (HDL-C), with reduced CRP concentrations, and, in cohort studies, with decreased risk of developing diabetes and cardiovascular disease. In addition, some case-control and cohort studies have found positive associations between dietary GI and risk of various cancers, including those of the colon, breast, and prostate. Although inconsistencies in the current findings still need to be resolved, sufficient positive evidence, especially with respect to renewed interest in postprandial events, suggests that the glycemic index may have a role to play in the treatment and prevention of chronic diseases.

  8. Refractive index measurements of Ge

    NASA Astrophysics Data System (ADS)

    Burnett, John H.; Kaplan, Simon G.; Stover, Eric; Phenis, Adam

    2016-09-01

    A program has been started at NIST to make high-accuracy measurements of the infrared (IR) index properties of technologically important IR materials, in order to provide the IR optics community with updated values for the highest quality materials now available. For this purpose, we designed and built a minimum-deviation-angle refractometry system enabling diffraction-limited index measurements for wavelengths from 0.12 μm to 14 μm. We discuss the apparatus and procedures that we use for IR measurements. First results are presented for germanium for the wavelength range from 2 μm to 14 μm, with standard uncertainties ranging from 2 × 10-5 near 2 μm to 8 × 10-5 near 14 μm. This is an improvement by about an order of magnitude of the uncertainty level for index data of germanium generally used for optic design. A Sellmeier formula fitting our data for this range is provided. An analysis of the uncertainty is presented in detail. These measurements are compared to previous measurements of Ge.

  9. 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

  10. 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).

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. Proteomic insights into metabolic adaptation to deletion of metE in Saccharopolyspora spinosa.

    PubMed

    Yang, Qi; Li, Yunlong; Yang, Huijun; Rang, Jie; Tang, Sijia; He, Lian; Li, Li; Ding, Xuezhi; Xia, Liqiu

    2015-10-01

    Saccharopolyspora spinosa can produce spinosad as a major secondary metabolite, which is an environmentally friendly agent for insect control. Cobalamin-independent methionine synthase (MetE) is an important enzyme in methionine biosynthesis, and this enzyme is probably closely related to spinosad production. In this study, its corresponding gene metE was inactivated, which resulted in a rapid growth and glucose utilisation rate and almost loss of spinosad production. A label-free quantitative proteomics-based approach was employed to obtain insights into the mechanism by which the metabolic network adapts to the absence of MetE. A total of 1440 proteins were detected from wild-type and ΔmetE mutant strains at three time points: stationary phase of ΔmetE mutant strain (S1ΔmetE , 67 h), first stationary phase of wild-type strain (S1WT, 67 h) and second stationary phase of wild-type strain (S2WT, 100 h). Protein expression patterns were determined using an exponentially modified protein abundance index (emPAI) and analysed by comparing S1ΔmetE /S1WT and S1ΔmetE /S2WT. Results showed that differentially expressed enzymes were mainly involved in primary metabolism and genetic information processing. This study demonstrated that the role of MetE is not restricted to methionine biosynthesis but rather is involved in global metabolic regulation in S. spinosa.

  19. Integrating understanding of hydrology, geomorphology and ecology to better predict periphyton abundance in New Zealand rivers

    NASA Astrophysics Data System (ADS)

    Hoyle, Jo; Kilroy, Cathy; Hicks, Murray

    2015-04-01

    Periphyton (the algae dominated community that grows on the bed of rivers) provide a rich food source for the upper trophic levels of stream ecosystems and can also provide an important ecological service by removing dissolved nutrients and contaminants from the flow. However, in excess, periphyton can have negative effects on habitat quality, water chemistry and biodiversity, and can reduce recreation and aesthetic values. The abundance of periphyton in rivers is influenced by a number of factors, but the two key factors that can be directly influenced by human activities are flow regime and nutrient concentrations. River managers in New Zealand are required to set objectives for periphyton abundance that meet or exceed national bottom lines, and they then need to set limits on freshwater quality and quantity in their region to ensure these objectives are met. Consequently, the ability to predict periphyton abundance under different conditions is crucial for management of rivers to protect ecological and other values. Establishing quantitative relationships between periphyton abundance, hydrologic regimes and nutrient concentrations has proven to be difficult but remains an urgent priority in New Zealand. A common index for predicting periphyton abundance has been the frequency of floods greater than 3 times the median flow (FRE3), and this has been successful on a regional average but can be quite unreliable on a site-specific basis. This stems largely from our limited ability to transform flow data into ecologically meaningful physical processes that directly affect periphyton removal (e.g., drag, abrasion, bed movement). The research we will present examines whether geomorphic variables, such as frequency of bed movement, are useful co-predictors in periphyton abundance-flow-nutrient relationships. We collected data on channel topography and bed material size for 20 reaches in the Manawatu-Wanganui Region which have at least 5 years of flow, nutrient

  20. Glophymed: an index to establish the ecological status for the Water Framework Directive based on phytoplankton in coastal waters.

    PubMed

    Romero, I; Pachés, M; Martínez-Guijarro, R; Ferrer, J

    2013-10-15

    Phytoplankton and its attributes (biomass, abundance, composition, and frequency and intensity of phytoplankton blooms) are essential to establish the ecological status in the Water Frame Directive. The aim of this study is to develop an index "Glophymed" based on all phytoplankton attributes for coastal water bodies according to the directive requirements. It is also developed an anthropogenic pressure index that takes into account population density, tourism, urbanization, industry, agriculture, fisheries and maritime transport for Comunitat Valenciana (Spain). Both indexes (Glophymed and human pressure index) based on a multisampling dataset collected monthly during several years, show a significant statistical correlation (r2 0.75 α<0.01) for typology IIA and (r2 0.93 α<0.01) for typology III-W. The relation between these indexes provides suitable information about the integrated management plans and protection measures of water resources since the Glophymed index is very sensitive to human pressures.

  1. 7 CFR 5.1 - Parity index and index of prices received by farmers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false Parity index and index of prices received by farmers. 5.1 Section 5.1 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.1 Parity index and index of prices received by farmers. (a) The parity index and related...

  2. 7 CFR 5.1 - Parity index and index of prices received by farmers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Parity index and index of prices received by farmers. 5.1 Section 5.1 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.1 Parity index and index of prices received by farmers. (a) The parity index and related...

  3. 7 CFR 5.1 - Parity index and index of prices received by farmers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Parity index and index of prices received by farmers. 5.1 Section 5.1 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.1 Parity index and index of prices received by farmers. (a) The parity index and related...

  4. 7 CFR 5.1 - Parity index and index of prices received by farmers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Parity index and index of prices received by farmers. 5.1 Section 5.1 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.1 Parity index and index of prices received by farmers. (a) The parity index and related...

  5. 7 CFR 5.1 - Parity index and index of prices received by farmers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Parity index and index of prices received by farmers. 5.1 Section 5.1 Agriculture Office of the Secretary of Agriculture DETERMINATION OF PARITY PRICES § 5.1 Parity index and index of prices received by farmers. (a) The parity index and related...

  6. 34 CFR Subject Index to Title IX... - Subject Index to Title IX Preamble and Regulation 1

    Code of Federal Regulations, 2010 CFR

    2016-07-01

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    2007-07-01

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    Code of Federal Regulations, 2010 CFR

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  14. 34 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation 1

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  15. 34 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation 1

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  16. 34 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation 1

    Code of Federal Regulations, 2010 CFR

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  17. 45 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation \\1\\

    Code of Federal Regulations, 2010 CFR

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  18. 45 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation 1

    Code of Federal Regulations, 2010 CFR

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  19. 34 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation 1

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  20. 45 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation 1

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  1. 34 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation 1

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  2. 45 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation \\1\\

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  3. 45 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation 1

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  4. 34 CFR Subject Index to Title Ix... - Subject Index to Title IX Preamble and Regulation 1

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  5. Experimental comparison between speech transmission index, rapid speech transmission index, and speech intelligibility index.

    PubMed

    Larm, Petra; Hongisto, Valtteri

    2006-02-01

    During the acoustical design of, e.g., auditoria or open-plan offices, it is important to know how speech can be perceived in various parts of the room. Different objective methods have been developed to measure and predict speech intelligibility, and these have been extensively used in various spaces. In this study, two such methods were compared, the speech transmission index (STI) and the speech intelligibility index (SII). Also the simplification of the STI, the room acoustics speech transmission index (RASTI), was considered. These quantities are all based on determining an apparent speech-to-noise ratio on selected frequency bands and summing them using a specific weighting. For comparison, some data were needed on the possible differences of these methods resulting from the calculation scheme and also measuring equipment. Their prediction accuracy was also of interest. Measurements were made in a laboratory having adjustable noise level and absorption, and in a real auditorium. It was found that the measurement equipment, especially the selection of the loudspeaker, can greatly affect the accuracy of the results. The prediction accuracy of the RASTI was found acceptable, if the input values for the prediction are accurately known, even though the studied space was not ideally diffuse.

  6. 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.

  7. 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.

  8. 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).

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. [Diversity and ichthyofaunistic abundance of the Rio Grande de Térraba, south of Costa Rica].

    PubMed

    Rodrigo Rojas, José; Rodríguez, Omar

    2008-09-01

    The diversity, abundance and distributional pattern of freshwater fish communities in the Térraba River, south Costa Rica, were investigated from the early dry season of 2004 to early rain season of 2005. There have been no preview studies on the freshwater fish distribution in Térraba. Therefore, the aims of this study were to determine fish species richness, abundance and distribution there. Fish sampling was done using a combination of gears such as gill net, fine mesh net and visual observation. Thirty three species, 26 genera and 14 families were collected in four sampling sites along the river. The number and biomass captured during the entire study was 984 individuals and 147 410.9 g respectively. Most of them are carnivorous species (48%), 33.3% are omnivorous and 12% detritivorous, and only two species are herbivorous. The most important species in relative abundance (56.5%) and biomass (53.7%) in the study area was the machaca (Brycon behreae). It should be clear that although the list of fish species that occur in Térraba River is reasonably complete, knowledge of their ichthyogeographic history patterns is superficial. The main community component was secondary freshwater species; with 17 invading brackish water species and one introduced species (tilapia O. niloticus). Nine species are reported for the first time in this river. The diversity index H' varied from 2.32 (El Brujo) to 1.67 (Coto), a similar pattern was also showed for the other indexes. Most of our results were similar to those of previous studies on freshwater fish distribution elsewhere, however no significant correlation between species distribution and environmental variables was found, and we hypothesized that the depth and water velocity and geomorphological are major environmental variables that influence the fish distribution. Our findings are opposed to the tendency, for species composition, to increase from upstream to the mouth of the river, which is probably due to two major

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Braking index of isolated pulsars

    NASA Astrophysics Data System (ADS)

    Hamil, O.; Stone, J. R.; Urbanec, M.; Urbancová, G.

    2015-03-01

    Isolated pulsars are rotating neutron stars with accurately measured angular velocities Ω , and their time derivatives that show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of detailed debate, the commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. Other processes, including the emission of gravitational radiation, and of relativistic particles (pulsar wind), are also being considered. The calculated energy loss by a rotating pulsar with a constant moment of inertia is assumed proportional to a model dependent power of Ω . This relation leads to the power law Ω ˙ =-K Ωn where n is called the braking index. The MDR model predicts n exactly equal to 3. Selected observations of isolated pulsars provide rather precise values of n , individually accurate to a few percent or better, in the range 1 index within the MDR model. Four microscopic equations of state are employed as input to two different computational codes that solve Einstein's equations numerically, either exactly or using the perturbative Hartle-Thorne method, to calculate the

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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).

  11. 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.

  12. 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.

  13. 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.

  14. 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}.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Study of biological communities subject to imperfect detection: Bias and precision of community N-mixture abundance models in small-sample situations

    USGS Publications Warehouse

    Yamaura, Yuichi; Kery, Marc; Royle, Andy

    2016-01-01

    Community N-mixture abundance models for replicated counts provide a powerful and novel framework for drawing inferences related to species abundance within communities subject to imperfect detection. To assess the performance of these models, and to compare them to related community occupancy models in situations with marginal information, we used simulation to examine the effects of mean abundance (λ¯: 0.1, 0.5, 1, 5), detection probability (p¯: 0.1, 0.2, 0.5), and number of sampling sites (n site : 10, 20, 40) and visits (n visit : 2, 3, 4) on the bias and precision of species-level parameters (mean abundance and covariate effect) and a community-level parameter (species richness). Bias and imprecision of estimates decreased when any of the four variables (λ¯, p¯, n site , n visit ) increased. Detection probability p¯ was most important for the estimates of mean abundance, while λ¯ was most influential for covariate effect and species richness estimates. For all parameters, increasing n site was more beneficial than increasing n visit . Minimal conditions for obtaining adequate performance of community abundance models were n site  ≥ 20, p¯ ≥ 0.2, and λ¯ ≥ 0.5. At lower abundance, the performance of community abundance and community occupancy models as species richness estimators were comparable. We then used additive partitioning analysis to reveal that raw species counts can overestimate β diversity both of species richness and the Shannon index, while community abundance models yielded better estimates. Community N-mixture abundance models thus have great potential for use with community ecology or conservation applications provided that replicated counts are available.

  1. Habitat Suitability Index Models: Beaver

    USGS Publications Warehouse

    Allen, Arthur W.

    1982-01-01

    Habitat preferences of the beaver (Castor canadensis) are described in this publication, which is one of a series of Habitat Suitability Index (HSI) models. Habitat use information is presented in a synthesis of the literature on the species-habitat requirements of the beaver, followed by the development of the HSI model. The model is designed to provide information for use in impact assessment and habitat management activities, and should be used in conjunction with habitat evaluation procedures previously developed by the Fish and Wildlife Service. This revised model updates the original publication dated September 1982.

  2. Sulfamethoxazole and COD increase abundance of sulfonamide resistance genes and change bacterial community structures within sequencing batch reactors.

    PubMed

    Guo, Xueping; Pang, Weihai; Dou, Chunling; Yin, Daqiang

    2017-05-01

    The abundant microbial community in biological treatment processes in wastewater treatment plants (WWTPs) may potentially enhance the horizontal gene transfer of antibiotic resistance genes with the presence of antibiotics. A lab-scale sequencing batch reactor was designed to investigate response of sulfonamide resistance genes (sulI, sulII) and bacterial communities to various concentrations of sulfamethoxazole (SMX) and chemical oxygen demand (COD) of wastewater. The SMX concentrations (0.001 mg/L, 0.1 mg/L and 10 mg/L) decreased with treatment time and higher SMX level was more difficult to remove. The presence of SMX also significantly reduced the removal efficiency of ammonia nitrogen, affecting the normal function of WWTPs. All three concentrations of SMX raised both sulI and sulII genes with higher concentrations exhibiting greater increases. The abundance of sul genes was positive correlated with treatment time and followed the second-order reaction kinetic model. Interestingly, these two genes have rather similar activity. SulI and sulII gene abundance also performed similar response to COD. Simpson index and Shannon-Weiner index did not show changes in the microbial community diversity. However, the 16S rRNA gene cloning and sequencing results showed the bacterial community structures varied during different stages. The results demonstrated that influent antibiotics into WWTPs may facilitate selection of ARGs and affect the wastewater conventional treatment as well as the bacteria community structures.

  3. Using larval fish abundance in the St. Clair and Detroit Rivers to predict year-class strength of forage fish in Lakes Huron and Erie

    USGS Publications Warehouse

    Hatcher, Charles O.; Nester, Robert T.; Muth, Kenneth M.

    1991-01-01

    Larval fish samples were collected in plankton tow nets in spring and summer, 1977–1978 and 1983–1984, in the St. Clair and Detroit rivers which are part of the connecting waterway between Lakes Huron and Erie. Larvae abundance of the major forage fish in the rivers are compared with their year-class abundance, as measured by bottom trawl catches of later life stages in Lakes Huron and Erie. Abundance of rainbow smelt, Osmerus mordax, and alewife, Alosa pseudo-harengus, larvae in the St. Clair River in adjacent years of the 4-year study was correlated with the abundance of yearlings captured in bottom trawls in lower Lake Huron in the spring of the following years. Abundance of locally produced larval rainbow smelt, alewives, and gizzard shad, Dorosoma cepedianum, in the Detroit River in adjacent years was correlated with the abundance oj’ young-of -t he-year captured in bottom trawls in western Lake Erie the following fall. Sampling fish larvae in the main channels of the St. Clair and Detroit rivers thus provided a potential early index of forage fish abundance in the lakes.

  4. Estimating wetland vegetation abundance from Landsat-8 operational land imager imagery: a comparison between linear spectral mixture analysis and multinomial logit modeling methods

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Gong, Zhaoning; Zhao, Wenji; Pu, Ruiliang; Liu, Ke

    2016-01-01

    Mapping vegetation abundance by using remote sensing data is an efficient means for detecting changes of an eco-environment. With Landsat-8 operational land imager (OLI) imagery acquired on July 31, 2013, both linear spectral mixture analysis (LSMA) and multinomial logit model (MNLM) methods were applied to estimate and assess the vegetation abundance in the Wild Duck Lake Wetland in Beijing, China. To improve mapping vegetation abundance and increase the number of endmembers in spectral mixture analysis, normalized difference vegetation index was extracted from OLI imagery along with the seven reflective bands of OLI data for estimating the vegetation abundance. Five endmembers were selected, which include terrestrial plants, aquatic plants, bare soil, high albedo, and low albedo. The vegetation abundance mapping results from Landsat OLI data were finally evaluated by utilizing a WorldView-2 multispectral imagery. Similar spatial patterns of vegetation abundance produced by both fully constrained LSMA algorithm and MNLM methods were observed: higher vegetation abundance levels were distributed in agricultural and riparian areas while lower levels in urban/built-up areas. The experimental results also indicate that the MNLM model outperformed the LSMA algorithm with smaller root mean square error (0.0152 versus 0.0252) and higher coefficient of determination (0.7856 versus 0.7214) as the MNLM model could handle the nonlinear reflection phenomenon better than the LSMA with mixed pixels.

  5. Multiple Timescale Comparison of the Aggregate Drought Index (ADI), the Standardized Precipitation Index (SPI), and Tree Rings in Southern California

    NASA Astrophysics Data System (ADS)

    Keyantash, J.; Sakata, C.

    2012-12-01

    The Aggregate Drought Index (ADI) [Keyantash and Dracup, 2004] is a drought index computed using the principal components of selected hydrological variables such as precipitation, evaporation, streamflow, reservoir storage, soil moisture, and alpine snowpack. Like the widely-used Standardized Precipitation Index (SPI), the ADI possesses the ability to simultaneously assess the shortage/abundance of water over a variety of desired timescales (e.g., 1 month, 12 month, 24 month, etc.). In this paper, the ADI is compared against the SPI, over multiple timescales, in the San Jacinto and Santa Ana River basins of Southern California. The comparisons occur between water years 1962 and 2011, an interval which spans three historic Southern California droughts (1976-77, 1987-1992, and 2007-2009). In both river basins, the drought indices are also compared against tree ring reconstructions of Big Cone Douglas Fir (Pseudotsuga macrocarpa), during a common crossover period in the latter 20th century. For historical perspective, the oldest tree ring reconstruction extends back to the year 1375.

  6. Indexing for ERIC. Volume 2, Lesson 1-Introduction to Indexing; Lesson 2-How to Index a Document.

    ERIC Educational Resources Information Center

    Langridge, D.W.; And Others

    This volume contains the first two lessons of a course in subject indexing based upon the Educational Resources Information Center (ERIC) Thesaurus, Lesson 1 is an introduction to indexing, containing definitions and concepts related to the theory of indexing and information retrieval as well as an introduction to the ERIC Thesaurus. Lesson 2 is…

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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.

  12. Scintillation Monitoring Using Asymmetry Index

    NASA Astrophysics Data System (ADS)

    Shaikh, Muhammad Mubasshir; Mahrous, Ayman; Abdallah, Amr; Notarpietro, Riccardo

    Variation in electron density can have significant effect on GNSS signals in terms of propagation delay. Ionospheric scintillation can be caused by rapid change of such delay, specifically, when they last for a longer period of time. Ionospheric irregularities that account for scintillation may vary significantly in spatial range and drift with the background plasma at speeds of 45 to 130 m/sec. These patchy irregularities may occur several times during night, e.g. in equatorial region, with the patches move through the ray paths of the GNSS satellite signals. These irregularities are often characterized as either ‘large scale’ (which can be as large as several hundred km in East-West direction and many times that in the North-South direction) or ‘small scale’ (which can be as small as 1m). These small scale irregularities are regarded as the main cause of scintillation [1,2]. In normal solar activity conditions, the mid-latitude ionosphere is not much disturbed. However, during severe magnetic storms, the aurora oval extends towards the equator and the equator anomaly region may stretched towards poles extending the scintillation phenomena more typically associated with those regions into mid-latitudes. In such stormy conditions, the predicted TEC may deviate largely from the true value of the TEC both at low and mid-latitudes due to which GNSS applications may be strongly degraded. This work is an attempt to analyze ionospheric scintillation (S4 index) using ionospheric asymmetry index [3]. The asymmetry index is based on trans-ionospheric propagation between GPS and LEO satellites in a radio occultation (RO) scenario, using background ionospheric data provided by MIDAS [4]. We attempted to simulate one of the recent geomagnetic storms (NOAA scale G4) occurred over low/mid-latitudes. The storm started on 26 September 2011 at UT 18:00 and lasted until early hours of 27 September 2011. The scintillation data for the storm was taken from an ionospheric

  13. Indexes to Nuclear Regulatory Commission Issuances, July--December 1993. Volume 38, Index 2

    SciTech Connect

    Not Available

    1994-04-01

    Digests and indexes for issuances of the Commission (CLI), the Atomic Safety and Licensing Board Panel (LBP), the Administrative Law Judges (ALJ), the Directors` Decisions (DD), and the Denials of Petitions for Rulemaking (DPRM) are presented in this document. These digests and indexes are intended to serve as a guide to the issuances. These information elements are displayed in one or more of five separate formats arranged as follows: Case Name Index; Digests and Headers; Legal Citations Index; Subject Index, and Facility Index.

  14. Baseband frequency response of a graded-index fiber excited by a step-index fiber.

    PubMed

    Horiguchi, T; Tanifuji, T; Tokuda, M

    1980-08-01

    Input modal power distribution and baseband frequency response of a graded-index fiber have been investigated theoretically and experimentally, when the fiber was excited by a step-index fiber. It is found that the bandwidth of the graded-index fiber is measured with good reproducibility and accuracy by using the step-index fiber as an exciter. An appropriate choice of step-index fiber parameters is made with respect to the test graded-index fiber.

  15. Indexes to Nuclear Regulatory Commission issuances, January--June 1995. Volume 41, Index 2

    SciTech Connect

    1995-09-01

    Digests and indexes for issuances of the Commission (CLI), the Atomic Safety and Licensing Board Panel (LBP), the Administrative Law Judges (ALJ), the directors` Decisions (DD), and the Denials of Petitions for rulemaking (DPRM) are presented in this document. These digests and indexes are intended to serve as a guide to the issuances. The information elements are displayed in one or more of five separate formats arranged as follows: Case name index; digests and headers; legal citations index; subject index; and facility index.

  16. Enhanced index tracking modelling in portfolio optimization

    NASA Astrophysics Data System (ADS)

    Lam, W. S.; Hj. Jaaman, Saiful Hafizah; Ismail, Hamizun bin

    2013-09-01

    Enhanced index tracking is a popular form of passive fund management in stock market. It is a dual-objective optimization problem, a trade-off between maximizing the mean return and minimizing the risk. Enhanced index tracking aims to generate excess return over the return achieved by the index without purchasing all of the stocks that make up the index by establishing an optimal portfolio. The objective of this study is to determine the optimal portfolio composition and performance by using weighted model in enhanced index tracking. Weighted model focuses on the trade-off between the excess return and the risk. The results of this study show that the optimal portfolio for the weighted model is able to outperform the Malaysia market index which is Kuala Lumpur Composite Index because of higher mean return and lower risk without purchasing all the stocks in the market index.

  17. Aerospace Medicine and Biology: Cumulative index, 1979

    NASA Technical Reports Server (NTRS)

    1980-01-01

    This publication is a cumulative index to the abstracts contained in the Supplements 190 through 201 of 'Aerospace Medicine and Biology: A Continuing Bibliography.' It includes three indexes-subject, personal author, and corporate source.

  18. 30 CFR 250.1401 - Index table.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Outer Continental Shelf Civil Penalties Outer Continental Shelf Lands Act Civil Penalties § 250.1401 Index table. The following table is an index of...

  19. 30 CFR 250.1401 - Index table.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Outer Continental Shelf Civil Penalties Outer Continental Shelf Lands Act Civil Penalties § 250.1401 Index table. The following table is an index of...

  20. 30 CFR 250.1401 - Index table.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Outer Continental Shelf Civil Penalties Outer Continental Shelf Lands Act Civil Penalties § 250.1401 Index table. The following table is an index of...