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Sample records for chemical u-th-pb dating

  1. Variscan crustal thickening in the Maures-Tanneron massif (South Variscan belt, France): new in situ monazite U-Th-Pb chemical dating of high-grade rocks

    International Nuclear Information System (INIS)

    Age constraints on the protoliths, deformation, metamorphism and melting events are key parameters when correlating different continental lithospheric remnants among each other and disentangling their evolution within large-scale orogens. In situ U-Th-Pb chemical dating on monazites using Electron Probe Micro-Analyser (EPMA) has been performed on eight samples throughout the Variscan Maures-Tanneron massif (SE France) in order to date the medium to high-tectono-thermal events related to the Variscan orogeny. Results indicate a poly-phased crustal evolution: (i) U-Th-Pb ages obtained in poly-genetic monazite grain cores gave inherited Upper Ordovician (456 ± 11 Ma) age, highlighting the large scale occurrence of the Ordovician magmatic activity in the North Gondwanian margin. An Early Devonian (404 ± 10 Ma) age may date a proto-lith emplacement related to calc-alkaline supra-subduction magmatism or could be associated to an early medium-grade metamorphism, prior to collisional stage. (ii) The crustal thickening stage has been further recorded in prograde metamorphic monazites formed during the under-thrusting and subsequent nappe stacking events, under amphibolite facies conditions. This stage is dated between 382 ± 11 (Middle Devonian) and 331 ± 5 Ma (Late Visean). (iii) An orogenic partial melting event took place during Middle Carboniferous and is accompanied by the crystallization of crustal peraluminous magmas (Plan-de-la-Tour granite, 329 ± 3 Ma). This contribution demonstrates the capacity of monazite to record the prograde path of rocks during increasing metamorphic conditions related to stages of crustal thickening, and the robustness of the U-Th-Pb chronometer in monazite despite the overprinting of high-grade thermal events, including partial melting. The age ranges of the different orogenic stages reported in this study are in good agreement with those reported in adjacent Variscan Corsica and Sardinia; while correlations with other nearest Variscan

  2. Chemical U-Th-Pb dating of monazite by 3D-Micro x-ray fluorescence analysis with synchrotron radiation

    DEFF Research Database (Denmark)

    Schmitz, Susanne; Möller, Andreas; Wilke, Max;

    2009-01-01

    A confocal set-up for three-dimensional (3D) micro X-ray fluorescence (micro-XRF) was used at the mySpot beamline at BESSY II, which allows compositional depth profiling for various applications. We present results obtained with a confocal 3D micro-XRF set-up for chemical age dating using the U, Th...... and Pb concentrations of monazite within rock thin sections. The probing volume was determined to be approximately 21 × 21 × 24 µm3 for W-La using an excitation energy of 19 keV. The relative detection limits particularly for Pb are below 10 ppm (for counting times of 1000 s). Therefore, this 3D micro-XRF...... ages, varying from 20 Ma to 1.82 Ga. Reference materials (GM3, F6, 3345) can be reproduced within error. The spread in the ages of all points determined by 3D micro-XRF is within 8 % of the isotopic reference value. The average 3D micro-XRF dates reproduce the reference ages with discrepancies between...

  3. Petrology and U-Th-Pb chemical monazite dating of the low-P metapelitic granulites at the region of Muzhaerte River in southwestern Tianshan, NW China, and their geological implications%新疆西南天山木扎尔特河一带低压泥质麻粒岩岩石学特征、独居石U-Th-Pb定年及其地质意义

    Institute of Scientific and Technical Information of China (English)

    苟龙龙; 张立飞

    2009-01-01

    During the closure of the South Tianshan Paleo-Ocean, a suite of low-pressure pelitic granulite-facies Crd-Grt-Sil-Bt gneiss was formed by the intrusion of arc magma into the landward continental margin of Muzhaerte River in South Tianshan, Xinjiang. Using the thermodynamic software of Theriak-Domino, we performed the NCKFMASH phase equilibria calculation on the Crd-Grt-Sil-Bt gneiss (WQ003) and the sillimanite-bearing Crd-Grt-Bt gneiss (WQ006) , and gained that their peak metamorphic conditions are T = 630 ~674℃ ,P = 5. 2~5.5kbar and T = 645 ~684℃ ,P = 5. 4 ~5. 7kbar, respectively. Moreover, we carried out the geochronological research on three monazite grains in sample WQ006 with the technique of U-Th-Pb chemical monazite dating by electron microprobe and got two characteristic isochron ages, 376 ±8Ma and 280 ±8Ma (2σ). Based on the petrographic study of monazite, 280 ±8Ma can be explained as the age of peak granulite-facies metamorphism, whereas 376 ± 8Ma (2σ) maybe represent the age of detrital or diagenesis, and we conclude that the subduction of South Tianshan oceanic crust began in Late Paleozoic and confirm the opinion that the subduction-collision of Southwest Tianshan orogen occurred after Late-Permian.%古南天山洋闭合过程中,由于洋壳俯冲产生的岛弧岩浆作用加热大陆地壳,在新疆西南天山木扎尔特一带形成了一套低压高温泥质麻粒岩相变质岩石.本文用Theriak-Domino热力学软件对该套岩石中的堇青石榴夕线石黑云母片麻岩和含夕线石堇青石榴黑云母片麻岩进行了岩石学相平衡计算研究,得到它们峰期变质的温压条件分别是:T=630~674℃,P=5.2~5.5kbar和T=645~684℃,P=5.4~5.7kbar.并采用独居石Th-U-Pb电子探针定年方法,对样品WQ006中的3颗独居石进行了原位年龄测定(38个分析点),得到2组等时线年龄,分别是376±8Ma和280σ8Ma(2σ).结合独居石的岩相学特征,提出了新

  4. Laser Ablation ICP-MS Titanite U-Th-Pb Dating of the Tonglushan Cu-Fe-Au Skarn Deposit, Southeastern Hubei Province%Laser Ablation ICP-MS Titanite U-Th-Pb Dating of the Tonglushan Cu-Fe-Au Skarn Deposit,Southeastern Hubei Province

    Institute of Scientific and Technical Information of China (English)

    LI Jian-wei; DENG Xiao-dong; ZHOU Mei-fu; LIU Yong-sheng

    2009-01-01

    @@ Titanite (CaTi_2SiO_5) is an important accessory mineral not only in magnatic and metamorphic rocks,but also commonly in hydrothermal mineral deposits.It incorporates appreciable amounts (usually 10 ×10~(-6) s to 100 × 10~(-6) s) of U and Th into its structure and has a closure temperature of Pb diffusion higher than 660 ~ 700 ℃ (Scott and St-Onge, 1995),making it an ideal U-Th-Pb geochronometer.

  5. The Carboniferous to Jurassic evolution of the pre-Alpine basement of Crete: Constraints from U-Pb and U-(Th)-Pb dating of orthogneiss, fission-track dating of zircon, structural and petrological data

    Czech Academy of Sciences Publication Activity Database

    Romano, S. S.; Brix, M. R.; Dörr, K.; Fiala, Jiří; Krenn, E.; Zulauf, G.

    2006-01-01

    Roč. 260, - (2006), s. 69-90. ISSN 0375-6440 Institutional research plan: CEZ:AV0Z30130516 Keywords : tectonic-evolution * Carboniferous * Jurassic * uranium-lead-dating * orthogneiss * fission-track-dating * zircon * structural-geology * petrology * metamorphism * high-temperature Subject RIV: DB - Geology ; Mineralogy

  6. U-Th-Pb systematics in zircon and titanite

    International Nuclear Information System (INIS)

    U-Th-Pb isotopic analyses of zircon and titanite were made for two core samples of granite from borehole ATK-1 drilled into the Eye-Dashwa Lakes pluton. One of the samples from near the bottom of the hole (990.97 to 996.78 m) yielded zircon and titanite that were slightly to severely disturbed isotopically. Eight fractions of zircon give an upper concordia intercept age of 2625 ± 16 Ma (MSWD = 34), which, based on an evaluation of the more concordant data points and on other geochronological results, is interpreted as being slightly too young. The time of crystallization is probably better approximated by the 207Pb/206Pb age of 2665 Ma determined on a slightly (∼8 percent) discordant titanite. The other sample from near the surface (3.85 to 9.61 m) generally revealed even more severely disturbed isotopic systematics for both zircon and titanite. The complex nature of the disturbances probably resulted from the penetration of meteoritic water into rock already modified by post-crystallization hydrothermal alteration. Nuclide migration occurred in both minerals -- during the Middle or Late Proterozoic for the zircon and during the modern weathering cycle for the titanite. Material balance calculations are used to demonstrate a recent relative gain of radiogenic Pb and/or loss of Th and U from the freshest-looking, least-altered titanite by exchange with altered, leucoxenite-bearing titanite

  7. U-Th-PbT Monazite Gechronology in the South Carpathian Basement: Variscan Syn-Metamorphic Tectonic Stacking and Long-Lasting Post-Peak Decompressional Overprints

    Science.gov (United States)

    Săbău, G.; Negulescu, E.

    2012-12-01

    Dating metamorphic events appears to be unsatisfactorily addressed by most of the widely-employed and otherwise accurate and productive isotopic techniques, because the phases and systems investigated do not directly relate to the metamorphic events themselves. An adequate answer to this challenge is instead provided by microprobe-assisted chemical U-Th-PbT monazite geochronology, by its spatial resolution, truly in situ character and the possibility to reference analyses against well-defined textural environments and features, as well as a qualitative timeframe derived therefrom. Though chemical U-Th-PbT monazite geochronology is increasingly applied to seek answers ranging form a general characterization to fine details of the thermotectonic evolution of magmatic and metamorphic rocks, there are so far, unlike in the case of isotopic geochronological methods, no clearly defined standard analytical and data processing protocols. Two main reasons for this have to be mentioned, namely that chemical U-Th-PbT chronology is actually a proxy for isotopic geochronology, and the quantification of the errors and their propagation cannot be directly assessed because apparent ages are related to the measured element concentrations by an implicit function, the law of radioactive decay. Current approaches rely on treating calculated individual age values as primary data, a priori grouping of analyses supposed (and subsequently tested) to be coeval, and their statistical processing in order to obtain age values. An alternative approach we applied in basement units of the South Carpathians consists in an explicit approximation of the age formula and associated errors propagated from element concentrations to age values, and individual treatment of each age datum. The separation of the age clusters from the overall age spectrum of each sample was operated by tracing the variations of the normalized age gradient on the age spectrum sorted by increasing age values, and fine

  8. Preliminary Report on U-Th-Pb Isotope Systematics of the Olivine-Phyric Shergottite Tissint

    Science.gov (United States)

    Moriwaki, R.; Usui, T.; Yokoyama, T.; Simon, J. I.; Jones, J. H.

    2014-01-01

    Geochemical studies of shergottites suggest that their parental magmas reflect mixtures between at least two distinct geochemical source reservoirs, producing correlations between radiogenic isotope compositions, and trace element abundances.. These correlations have been interpreted as indicating the presence of a reduced, incompatible-element- depleted reservoir and an oxidized, incompatible-element-rich reservoir. The former is clearly a depleted mantle source, but there has been a long debate regarding the origin of the enriched reservoir. Two contrasting models have been proposed regarding the location and mixing process of the two geochemical source reservoirs: (1) assimilation of oxidized crust by mantle derived, reduced magmas, or (2) mixing of two distinct mantle reservoirs during melting. The former clearly requires the ancient martian crust to be the enriched source (crustal assimilation), whereas the latter requires a long-lived enriched mantle domain that probably originated from residual melts formed during solidification of a magma ocean (heterogeneous mantle model). This study conducts Pb isotope and U-Th-Pb concentration analyses of the olivine-phyric shergottite Tissint because U-Th-Pb isotope systematics have been intensively used as a powerful radiogenic tracer to characterize old crust/sediment components in mantle- derived, terrestrial oceanic island basalts. The U-Th-Pb analyses are applied to sequential acid leaching fractions obtained from Tissint whole-rock powder in order to search for Pb isotopic source components in Tissint magma. Here we report preliminary results of the U-Th-Pb analyses of acid leachates and a residue, and propose the possibility that Tissint would have experienced minor assimilation of old martian crust.

  9. Formation ages and evolution of Shergotty and its parent planet from U-Th-Pb systematics

    International Nuclear Information System (INIS)

    The isotopic composition of lead was determined in different phases from Shergotty, Zagami and EETA 79001. Using phases with low 238U/204Pb, the initial leads of these meteorites could be well defined and are distinct from each other and have high 204Pb/206Pb (from 0.0652 to 0.0739). These leads evolved in different reservoirs over most of solar system history in a low 238U/204Pb approx. equal to 5 environment. It follows that the parent planet of the shergottites has a high 204Pb concentration relative to U and must also be high in other volatiles. If the parent planet of the shergottites is Mars, then this planet must be volatile-rich compared to the Earth by a factor of approx. 1.8. The U-Th-Pb isotopic relationships involving phases with high 238U/204Pb are quite regular and give ages for three shergottites which indicate an event of U-Th-Pb fractionation at approx. 200 m.y. The initial leads at that time were highly evolved relative to the primordial lead. The absence of substantial additions of radiogenic lead (above the initial lead) in high U phases precludes an older age for the U-Th-Pb fractionation. However, details of the data arrays are complex. (author)

  10. Evaluation of potential of adsorption of U, Th, Pb, Zn and Ni by coconut fibers

    International Nuclear Information System (INIS)

    The residual biomass from agricultural activities has been evaluated as biosorbent for metals and organic composts from aqueous solutions, because of its adsorptive properties, low cost, abundance and to be a renewable resource. In this work, the efficiency of coir pith as biosorbent for the removal of U, Th, Pb, Zn e Ni ions from the aqueous solutions is presented. The coir pith is a by-product of the harvest of the coconut, a renewable natural source. The study was conducted by batch method. The influence of pH from 1 to 8, the dosage of the coir pith and the equilibrium time were studied. The adsorption of metal ions increased with the increase of pH and the dose. The Langmuir and Freundlich models were applied to describe the adsorption equilibrium isotherm. The kinetic process was studied using the pseudo-first order and pseudo-second order models. The Gibbs free energy was calculated. In the concentration range of 100 mg.L-1 - 500 mg.L-1, the adsorption process was described better by the Langmuir equation for Pb2+ and Zn2+ ions and the Freundlich equation for UO2 2+, Th4+ and Ni2+ ions, and represented by the pseudo-second order model. The biosorption process for removal of metal ions from the solutions was considered spontaneous. The results were promising, showing perspectives of application of coir pith as biosorbent of U, Th, Pb, Zn and Ni ions in wastewater treatment processes. (author)

  11. Evaluation of potential of adsorption of U, Th, Pb, Zn and Ni by coconut fibers; Avaliacao do potencial de adsorcao de U, Th, Pb, Zn e Ni pelas fibras de coco

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Raquel Almeida

    2009-07-01

    The residual biomass from agricultural activities has been evaluated as biosorbent for metals and organic composts from aqueous solutions, because of its adsorptive properties, low cost, abundance and to be a renewable resource. In this work, the efficiency of coir pith as biosorbent for the removal of U, Th, Pb, Zn e Ni ions from the aqueous solutions is presented. The coir pith is a by-product of the harvest of the coconut, a renewable natural source. The study was conducted by batch method. The influence of pH from 1 to 8, the dosage of the coir pith and the equilibrium time were studied. The adsorption of metal ions increased with the increase of pH and the dose. The Langmuir and Freundlich models were applied to describe the adsorption equilibrium isotherm. The kinetic process was studied using the pseudo-first order and pseudo-second order models. The Gibbs free energy was calculated. In the concentration range of 100 mg.L{sup -1} - 500 mg.L{sup -1}, the adsorption process was described better by the Langmuir equation for Pb{sup 2+} and Zn{sup 2+} ions and the Freundlich equation for UO{sub 2} 2{sup +}, Th{sup 4+} and Ni{sup 2+} ions, and represented by the pseudo-second order model. The biosorption process for removal of metal ions from the solutions was considered spontaneous. The results were promising, showing perspectives of application of coir pith as biosorbent of U, Th, Pb, Zn and Ni ions in wastewater treatment processes. (author)

  12. Petrology and geochronology of ultra-high temperature granulites of the basic unit of Andriamena (north-central Madagascar). Contribution of in-situ U-Th-Pb geochronology to the interpretation of P-T paths

    International Nuclear Information System (INIS)

    reached thanks to the punctual and in-situ dating methods which allow to date the minerals in their textural context and thus to correlate the metamorphic mineralogy with the age. Therefore, a new method of in-situ U-Th-Pb dating on monazite has been developed which uses the chemical (microprobe) and conventional isotopic (ID-TIMS) methods. Using both methods, a high spatial resolution is combined to a high analytical precision. The particularity of this new approach is that the isotopic dating is performed on individual grains extracted by micro-drilling on the thin section after their determination by electron microprobe. The textural position of each dated grain is thus recorded. (J.S.)

  13. Petrology and geochronology of ultra-high temperature granulites of the basic unit of Andriamena (north-central Madagascar). Contribution of in-situ U-Th-Pb geochronology to the interpretation of P-T paths; Petrologie et geochronologie des granulites de ultra-hautes temperatures de l'unite basique d'Andriamena (Centre-Nord Madagascar). Apport de la geochronologie in-situ U-Th-Pb a l'interpretation des trajets P-T

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Ph

    2002-10-01

    reached thanks to the punctual and in-situ dating methods which allow to date the minerals in their textural context and thus to correlate the metamorphic mineralogy with the age. Therefore, a new method of in-situ U-Th-Pb dating on monazite has been developed which uses the chemical (microprobe) and conventional isotopic (ID-TIMS) methods. Using both methods, a high spatial resolution is combined to a high analytical precision. The particularity of this new approach is that the isotopic dating is performed on individual grains extracted by micro-drilling on the thin section after their determination by electron microprobe. The textural position of each dated grain is thus recorded. (J.S.)

  14. Sequential separation of ultra-trace U, Th, Pb, and lanthanides using a simple automatic system.

    Science.gov (United States)

    Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki

    2015-07-01

    Uranium, thorium, lead, and the lanthanides were automatically and sequentially separated with a single anion-exchange column. This separation was achieved using eluents consisting of a simple and highly pure acid mixture of HCl, HNO3, acetic acid, and HF. The elements of interest were separated from the major constituents, which included alkaline metal elements, alkaline earth metal elements, and iron. This simple and automatic system is driven with pressurized nitrogen gas and controlled using a computer program. An optimized separation was accomplished under the following conditions: a 50 mm long and 2 mm diameter column, 11 μm diameter anion-exchange resin, and a 35 μL min(-1) flow rate. Using this system, 50 ng of varied elements in a 100 μL feed solution were perfectly separated within 5 h with >400 decontamination factors and >95% yield. In order to evaluate the performance of this system, a reference powdered rock sample was separated using this system. Abundances of objective elements, including 0.23 ng of lutetium, were accurately determined without corrections of chemical recovery yield or subtraction of the process blank. This separation technique saves time and effort for chemical processing, and is useful for ultra-trace quantitative and isotopic analyses of elements in small environmental samples. PMID:25994104

  15. U-Th-Pb isotope data indicate phanerozoic age for oxidation of the 3.4 Ga Apex Basalt

    Science.gov (United States)

    Li, Weiqiang; Johnson, Clark M.; Beard, Brian L.

    2012-02-01

    The occurrence of ferric oxides in Archean rocks has played an important role in discussions on the amount of free oxygen in the atmosphere of the ancient Earth. Recognizing that post-Archean weathering may also produce oxide minerals, drill cores have been used to obtain samples beneath the depth of Phanerozoic weathering. The first core of the Archean Biosphere Drilling Project (ABDP-1) documented hematite as alteration products in 3.4 Ga basalts from the Marble Bar area of the Pilbara Craton, NW Australia, and this has been used to infer the presence of an O2-bearing atmosphere in the Archean. It is possible, however, that despite recovery of samples from > 100 m depth, oxidation of the basalts occurred much younger than the depositional age. In this study, the age of oxidation of the Apex Basalt from the ABDP-1 drill core at Marble Bar is constrained by U-Th-Pb geochronology. Lead and U concentrations of the basalts from the ABDP-1 drill core vary greatly, between < 1-58 ppm and 0.08-1.04 ppm, respectively, whereas Th contents are more restricted (0.24-0.71 ppm). 206Pb/204Pb ratios are non-radiogenic and vary from 12.44 to 14.69. The linear array in terms of 206Pb/204Pb-207Pb/204Pb variations does not reflect an age but reflects two-component mixing between a non-radiogenic "ore lead" end member and a radiogenic "basalt lead" end member. The samples do not form isochrons on 238U/204Pb-206Pb/204Pb, 235U/204Pb-207Pb/204Pb, or 232Th/204Pb-208Pb/204Pb diagrams, indicating post-formation U and Pb addition. Comparison of measured U/Th ratios with "model" U/Th ratios calculated based on 208Pb/204Pb-206Pb/204Pb variations indicates that U enrichment most likely occurred in the last 200 Ma. The degree of U enrichment in the samples is correlated with Fe(III)/FeTotal ratios, indicating that U addition and oxidation were related, most likely reflecting penetration of oxygenated surface waters in the Phanerozoic along bedding planes and shear zones. These results

  16. Chemical Principles Revisited: Archaeological Dating.

    Science.gov (United States)

    Rowe, M. W.

    1986-01-01

    Discusses methods used to date archaeological artifacts and other remains. They include: (1) nuclear dating techniques (radiocarbon dating, accelerator radiocarbon dating, thermoluminescence, and others); (2) chemical dating techniques (amino acid racemization, obsidian hydration dating, elemental content changes, and thermal analysis dating); and…

  17. Monazite U-Th-Pb EPMA and zircon U-Pb SIMS chronological constraints on the tectonic, metamorphic, and thermal events in the inner part of the Variscan orogen, example from the Sioule series, French Massif Central

    Science.gov (United States)

    Do Couto, Damien; Faure, Michel; Augier, Romain; Cocherie, Alain; Rossi, Philippe; Li, Xian-Hua; Lin, Wei

    2016-03-01

    In the northern Variscan French Massif Central, the Sioule metamorphic series exposes from top to bottom the tectonic superposition of the Upper Gneiss Unit (UGU), Lower Gneiss Unit (LGU), and Para-autochthonous Unit (PAU). The nappe stacking developed throughout two prograde syn-metamorphic events: D1 is a top-to-the-SW shearing coeval with a probable Devonian migmatization and D2 is a top-to-the-NW shearing event. Both events were completed before the unconformable deposition of the undeformed and unmetamorphosed "Tufs anthracifères" formation, dated at ca 330 Ma (Late Visean). Furthermore, the UGU experienced a high-pressure metamorphism ascribed to a D0 event during which eclogite or granulite crystallized in several parts of the UGU. Monazite U-Th-Pb and zircon U-Pb SIMS datings were carried out in order to constrain the ages of these D0, D1, and D2 tectono-metamorphic events. These new geochronological results are placed in a P-T-t diagram constructed for the UGU, LGU, and PAU. Monazite sampled in UGU, LGU, and PAU rocks yields similar 365-350 Ma ages consistent with the D2 event dated in other places of the French Massif Central. A zoned monazite grain from a granulitic paragneiss yields 416 ± 15 and 362 ± 14 Ma ages interpreted as those of the D0 and D2 events, respectively. Zircon from the same granulitic paragneiss yields SIMS ages at 343 ± 2 and 328 ± 2 Ma that are interpreted as recrystallization processes associated with post-thickening thermal events, possibly recording the onset of orogenic collapse of the Northern Massif Central. It is worth to note that neither monazite nor zircon recorded the D1 event.

  18. Age relationships from U-Th-Pb isotope studies of uranium mineralization in Wernecke breccias, Yukon Territory

    International Nuclear Information System (INIS)

    Pb-U ± Th isotope analyses for 17 specimens of uraniferous breccia from the northeastern Wernecke Mountains reveal several apparent ages for mineralization. The oldest date, 1194 Ma, reflects either initial emplacement of the breccias or their modification by effects of the Rackla of Rapitan (Windermere) thick clastic wedges and iron formation. The 510 Ma date reflects mid-Cambrian mineralization roughly coincident with regional uplift (and attendant karstification) and development of thick clastic wedges. This was also an important period for Pb-Zn mineralization. Younger dates resulted from continuing remobilization, and all isotopic ages for mineralized breccia reflect movements associated with the Richardson Fault array

  19. Zirconolite, zircon and monazite-(Ce) U-Th-Pb age constraints on the emplacement, deformation and alteration history of the Cummins Range Carbonatite Complex, Halls Creek Orogen, Kimberley region, Western Australia

    Science.gov (United States)

    Downes, Peter J.; Dunkley, Daniel J.; Fletcher, Ian R.; McNaughton, Neal J.; Rasmussen, Birger; Jaques, A. Lynton; Verrall, Michael; Sweetapple, Marcus T.

    2016-04-01

    In situ SHRIMP U-Pb dating of zirconolite in clinopyroxenite from the Cummins Range Carbonatite Complex, situated in the southern Halls Creek Orogen, Kimberley region, Western Australia, has provided a reliable 207Pb/206Pb age of emplacement of 1009 ± 16 Ma. Variably metamict and recrystallised zircons from co-magmatic carbonatites, including a megacryst ~1.5 cm long, gave a range of ages from ~1043-998 Ma, reflecting partial isotopic resetting during post-emplacement deformation and alteration. Monazite-(Ce) in a strongly foliated dolomite carbonatite produced U-Th-Pb dates ranging from ~900-590 Ma. Although the monazite-(Ce) data cannot give any definitive ages, they clearly reflect a long history of hydrothermal alteration/recrystallisation, over at least 300 million years. This is consistent with the apparent resetting of the Rb-Sr and K-Ar isotopic systems by a post-emplacement thermal event at ~900 Ma during the intracratonic Yampi Orogeny. The emplacement of the Cummins Range Carbonatite Complex probably resulted from the reactivation of a deep crustal structure within the Halls Creek Orogen during the amalgamation of Proterozoic Australia with Rodinia over the period ~1000-950 Ma. This may have allowed an alkaline carbonated silicate magma that was parental to the Cummins Range carbonatites, and generated by redox and/or decompression partial melting of the asthenospheric mantle, to ascend from the base of the continental lithosphere along the lithospheric discontinuity constituted by the southern edge of the Halls Creek Orogen. There is no evidence of a link between the emplacement of the Cummins Range Carbonatite Complex and mafic large igneous province magmatism indicative of mantle plume activity. Rather, patterns of Proterozoic alkaline magmatism in the Kimberley Craton may have been controlled by changing plate motions during the Nuna-Rodinia supercontinent cycles (~1200-800 Ma).

  20. LASS U-Th-Pb monazite and rutile geochronology of felsic high-pressure granulites (Rhodope, N Greece): Effects of fluid, deformation and metamorphic reactions in local subsystems

    Science.gov (United States)

    Wawrzenitz, Nicole; Krohe, Alexander; Baziotis, Ioannis; Mposkos, Evripidis; Kylander-Clark, Andrew R. C.; Romer, Rolf L.

    2015-09-01

    The specific chemical composition of monazite in shear zones is controlled by the syndeformation dissolution-precipitation reactions of the rock-forming minerals. This relation can be used for dating deformation, even when microfabric characteristics like shape preferred orientation or intracrystalline deformation of monazite itself are missing. Monazite contemporaneously formed in and around the shear zones may have different compositions. These depend on the local chemical context rather than reflecting successive crystallization episodes of monazite. This is demonstrated in polymetamorphic, mylonitic high-pressure (HP) garnet-kyanite granulites of the Alpine Sidironero Complex (Rhodope UHP terrain, Northern Greece). The studied mylonitic rocks escaped from regional migmatization at 40-36 Ma and from subsequent shearing through cooling until 36 Ma. In-situ laser-ablation split-stream inductively-coupled plasma mass spectrometry (LASS) analyses have been carried out on monazite from micro-scale shear zones, from pre-mylonitic microlithons as well as of monazite inclusions in relictic minerals complimented by U-Pb data on rutile and Rb-Sr data of biotite. Two major metamorphic episodes, Mesozoic and Cenozoic, are constrained. Chemical compositions, isotopic characteristics and apparent ages systematically vary among monazite of four different microfabric domains (I-IV). Within three pre-mylonitic domains (inclusions in (I) pre-mylonitic kyanite and (II) garnet porphyroclasts, and (III) in pre-mylonitic microlithons) monazite yields ages of ca. 130-150 Ma for HP-granulite metamorphism, in line with previous geochronological results in the area. Patchy alteration of the pre-mylonitic monazite by intra-grain dissolution-precipitation processes variably increased negative Eu anomaly and reduced the HREE contents. The apparent age of this altered monazite is reduced. Monazite in the syn-mylonitic shear bands (IV) differs in chemical composition from unaltered and

  1. Lattice distortion in a zircon population and its effects on trace element mobility and U-Th-Pb isotope systematics: examples from the Lewisian Gneiss Complex, northwest Scotland

    Science.gov (United States)

    MacDonald, John M.; Wheeler, John; Harley, Simon L.; Mariani, Elisabetta; Goodenough, Kathryn M.; Crowley, Quentin; Tatham, Daniel

    2013-07-01

    Zircon is a key mineral in geochemical and geochronological studies in a range of geological settings as it is mechanically and chemically robust. However, distortion of its crystal lattice can facilitate enhanced diffusion of key elements such as U and Pb. Electron backscatter diffraction (EBSD) analysis of ninety-nine zircons from the Lewisian Gneiss Complex (LGC) of northwest Scotland has revealed five zircons with lattice distortion. The distortion can take the form of gradual bending of the lattice or division of the crystal into subgrains. Zircon lattices are distorted because of either post-crystallisation plastic distortion or growth defects. Three of the five distorted zircons, along with many of the undistorted zircons in the population, were analysed by ion microprobe to measure U and Pb isotopes, Ti and REEs. Comparison of Th/U ratio, 207Pb/206Pb age, REE profile and Ti concentration between zircons with and without lattice distortion suggests that the distortion is variably affecting the concentration of these trace elements and isotopes within single crystals, within samples and between localities. REE patterns vary heterogeneously, sometimes relatively depleted in heavy REEs or lacking a Eu anomaly. Ti-in-zircon thermometry records temperatures that were either low (~700 °C) or high (>900 °C) relative to undistorted zircons. One distorted zircon records apparent 207Pb/206Pb isotopic ages (-3.0 to +0.3 % discordance) in the range of ~2,420-2,450 Ma but this does not correlate with any previously dated tectonothermal event in the LGC. Two other distorted zircons give discordant ages of 2,331 ± 22 and 2,266 ± 40 Ma, defining a discordia lower intercept within error of a late amphibolite-facies tectonothermal event. This illustrates that Pb may be mobilised in distorted zircons at lower metamorphic grade than in undistorted zircons. These differences in trace element abundances and isotope systematics in distorted zircons relative to undistorted

  2. Accessory mineral U-Th-Pb ages and 40Ar/39Ar eruption chronology, and their bearing on rhyolitic magma evolution in the Pleistocene Coso volcanic field, California

    Science.gov (United States)

    Simon, J.I.; Vazquez, J.A.; Renne, P.R.; Schmitt, A.K.; Bacon, C.R.; Reid, M.R.

    2009-01-01

    We determined Ar/Ar eruption ages of eight extrusions from the Pleistocene Coso volcanic field, a long-lived series of small volume rhyolitic domes in eastern California. Combined with ion-microprobe dating of crystal ages of zircon and allanite from these lavas and from granophyre geothermal well cuttings, we were able to track the range of magma-production rates over the past 650 ka at Coso. In ??? 230 ka rhyolites we find no evidence of protracted magma residence or recycled zircon (or allanite) from Pleistocene predecessors. A significant subset of zircon in the ???85 ka rhyolites yielded ages between ???100 and 200 Ma, requiring that generation of at least some rhyolites involves material from Mesozoic basement. Similar zircon xenocrysts are found in an ???200 ka granophyre. The new age constraints imply that magma evolution at Coso can occur rapidly as demonstrated by significant changes in rhyolite composition over short time intervals (???10's to 100's ka). In conjunction with radioisotopic age constraints from other young silicic volcanic fields, dating of Coso rhyolites highlights the fact that at least some (and often the more voluminous) rhyolites are produced relatively rapidly, but that many small-volume rhyolites likely represent separation from long-lived mushy magma bodies. ?? The Author(s) 2009.

  3. Rare-element granitic pegmatite of Miocene age emplaced in UHP rocks from Visole, Pohorje Mountains (Eastern Alps, Slovenia): accessory minerals, monazite and uraninite chemical dating

    Science.gov (United States)

    Uher, Pavel; Janák, Marian; Konečný, Patrik; Vrabec, Mirijam

    2014-04-01

    The granitic pegmatite dike intruded the Cretaceous UHP rocks at Visole, near Slovenska Bistrica, in the Pohorje Mountains (Slovenia). The rock consists mainly of K-feldspar, albite and quartz, subordinate muscovite and biotite, while the accessory minerals include spessartine-almandine, zircon, ferrocolumbite, fluorapatite, monazite- (Ce), uraninite, and magnetite. Compositions of garnet (Sps48-49Alm45-46Grs + And3-4 Prp1.5-2), metamict zircon with 3.5 to 7.8 wt. % HfO2 [atom. 100Hf/(Hf + Zr) = 3.3-7.7] and ferrocolumbite [atom. Mn/(Mn + Fe) = 0.27-0.43, Ta/(Ta + Nb) = 0.03-0.46] indicate a relatively low to medium degree of magmatic fractionation, characteristic of the muscovite - rare-element class or beryl-columbite subtype of the rare-element class pegmatites. Monazite-(Ce) reveals elevated Th and U contents (≤11 wt. % ThO2, ≤5 wt. % UO2). The monazite-garnet geothermometer shows a possible precipitation temperature of ~495 ± 30 °C at P~4 to 5 kbar. Chemical U-Th-Pb dating of the monazite yielded a Miocene age (17.2 ± 1.8 Ma), whereas uraninite gave a younger (~14 Ma) age. These ages are comtemporaneous with the main crystallization and emplacement of the Pohorje pluton and adjacent volcanic rocks (20 to 15 Ma), providing the first documented evidence of Neogene granitic pegmatites in the Eastern Alps. Consequently, the Visole pegmatite belongs to the youngest rare-element granitic pegmatite populations in Europe, together with the Paleogene pegmatite occurrences along the Periadriatic (Insubric) Fault System in the Alps and in the Rhodope Massif, as well as the Late Miocene to Pliocene pegmatites in the Tuscany magmatic province (mainly on the Island of Elba).

  4. Interim report task 2: performance testing - task 2.4: natural mineral analog studies physical and chemical characteristics of brannerite in natural systems to Lawrence Livermore National Laboratory under contract B345772

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, G R; Colella, M; Leung, S H F

    2000-04-30

    To investigate the long-term alteration behavior of brannerite, we have undertaken a study of 13 natural samples from various geological environments, including granites, granitic pegmatites, quartz veins, and placer deposits. Literature data and U-Th-Pb chemical dating carried out in this work indicate that the samples range in age from approximately 20 Ma to 1580 Ma. Where independent age data or estimates are available for comparison, the U-Th-Pb chemical ages are in reasonable agreement for the younger samples, but the older samples tend to show evidence for Pb loss (up to about 80%), a common feature of metamict Nb, Ta, and Ti oxide minerals. Our results show that many of the samples exhibit only minor alteration, usually within small patches, microfractures, or around the rims of the brannerite crystals. Other samples consist of variable amounts of unaltered and altered brannerite. Heavily altered samples may contain anatase and thorite as fine-grained alteration products. Certain samples exhibited fracturing of the associated rock matrix or mineral phase in the immediate vicinity of the brannerite grains. These fractures contain U bearing material and indicate that some U migrated locally from the source brannerite.

  5. Application of U-Th-Pb phosphate geochronology to young orogenic gold deposits: New age constraints on the formation of the Grass Valley gold district, Sierra Foothills province, California

    Science.gov (United States)

    Taylor, Ryan D.; Goldfarb, Richard J.; Monecke, Thomas; Fletcher, Ian R.; Cosca, Michael A.; Kelly, Nigel M.

    2015-01-01

    The Grass Valley orogenic gold district in the Sierra Nevada foothills province, central California, the largest historic gold producer of the North American Cordillera, comprises both steeply dipping east-west (E-W) veins located along lithologic contacts in accreted ca. 300 and 200 Ma oceanic rocks and shallowly dipping north-south (N-S) veins hosted by the Grass Valley granodiorite; the latter have yielded about 70 percent of the 13 million ounces of historic lode gold production in the district. The oceanic host rocks were accreted to the western margin of North America between 200 and 170 Ma, metamorphosed to greenschist and amphibolite facies, and uplifted between 175 and 160 Ma. Large-scale magmatism in the Sierra Nevada occurred between 170-140 Ma and 120-80 Ma, with the Grass Valley granodiorite being emplaced during the older episode of magmatism. Uranium-lead isotopic dating of hydrothermal xenotime yielded the first absolute age of 162±5 Ma for the economically more significant N-S veins. The vein-hosted xenotime, as well as associated monazite, are unequivocally of hydrothermal origin as indicated by textural and chemical characteristics, including grain shape, lack of truncated growth banding, lack of a Eu anomaly, and low U and Th concentrations. Furthermore, the crack-seal texture of the veins, with abundant wallrock slivers, suggests their formation as a result of episodic fluid flow possibly related to reoccurring seismic events, rather than a period of fluid exsolution from an evolving magma. The N-S veins are temporally distinct from a younger 153-151 Ma gold event that was previously reported for the E-W veins. Overlapping U-Pb zircon (159.9±2.2 Ma) and 40Ar/39Ar biotite and hornblende (159.7±0.6 to 161.9±1.4 Ma) ages and geothermobarometric calculations indicate that the Grass Valley granodiorite was emplaced at ca. 160 Ma at elevated temperatures (~800°C) within approximately 3 km of the paleosurface and rapidly cooled to the ambient

  6. Monitoring and Microbiological Characteristics of Physico-chemical Dates of Canned Juice by Gamma Irradiation

    International Nuclear Information System (INIS)

    During this work, we are interested to the survey of the effect of gamma irradiation on the conservation of the juices of the dates. The results gotten of the microbiological and physico-chemical analysis done on the four samples, show the efficiency of the method for the conservation of the juices of the dates. (Author)

  7. MINERAL CONTENTS AND PHYSICAL, CHEMICAL, SENSORY PROPERTIES OF ICE CREAM ENRICHED WITH DATE FIBRE

    Directory of Open Access Journals (Sweden)

    Filiz Yangılar

    2015-09-01

    Full Text Available Date samples of Amber cultivar straining from Medina region (Saudi Arabia were analysed for their chemical compositions and physicochemical properties of date fibre in the present study. Fibre rich date pieces were found to contain 80.2 g/100 g total dietary fibre, 16.32 g water/g sample water-holding capacity while 9.50 g oil/g sample oil-holding capacity. It can be stated from these results that fibre content of date is a valuable dietary fibre source and used in food production as an ingredient. Effects of the addition of date fibres at different concentrations (1, 2, 3 and 4% were investigated on the physical, chemical, sensory properties and mineral content of ice cream in the present study. It was found that elemental composition of ice cream samples was affected significantly by the addition of date fibre concentrations (p<0.05 and the rates of K, Mg and Zn especially increased in the samples depending on the content of date fibre while the content of Ca and P decreased. It was determined from the sensory results that ice cream sample containing date fibre in the rate of 1 and 2% received the highest score from panellists.

  8. Physico-Chemical Characteristics of Pollinated and Non Pollinated Date Fruit of District Khairpur, Sindh, Pakistan

    Directory of Open Access Journals (Sweden)

    Wahid Bux Jatoi

    2012-12-01

    Full Text Available Elemental patterns are often used for the classification or identification of date fruit varieties. Five ripening stages of six date varieties were collected and studied from the pre ripening to the post ripening stage. Pollinated and non-pollinated date fruit of the same varieties were compared for their physical and chemical parameters. Physical parameters such as size, mass, colour, moisture, and pH were measured. In case of chemical characteristics the mineral composition of six different varieties of district Khairpur dates palm (Phoenix dactylifera L. fruit (Gorho, Asul Khurmo, Nur Aseel, Ghuray Wari, Toto, and Allah Wari were analysed using Atomic Absorption Spectroscopy (AAS. Generally, size, moisture and mineral content of the pollinated fruit increased up to 3rd and 4th stage then declined.

  9. Physico-Chemical Characteristics of Date Seed Oil Grown in Sudan

    OpenAIRE

    Rehab Salih Mahmoud Abdalla; Alsheikh AlGilani Albasheer; Abdel Rahim Mohamed ELHussein; ELrasheed Ahmed Gadkariem

    2012-01-01

    Problem statement: Studies were conducted on the physical-chemical properties of Sudanese date seed oil extracted from two date palm cultivars (Phoenix dactylifera L.) ALBarakawi and Alqundeila. The extracted oil from ALBarakawi seeds weighed 6.833% w/w oil, Alqundeila oil extracted weighed 5.064% w/w. Approach: The physical properties of ALBarakawi oil were: viscosity: 17cp, refractive Index: 1.444, density: 0.9116 g cm-3 color: Within the range 1. 6-11.1 (red-yellow). For Alqundeila the phy...

  10. Chemical composition, antioxidant capacity, and mineral extractability of Sudanese date palm (Phoenix dactylifera L.) fruits

    Science.gov (United States)

    Mohamed, Rania M A; Fageer, Aisha S M; Eltayeb, Mohamed M; Mohamed Ahmed, Isam A

    2014-01-01

    The aim of the present work was to investigate the chemical composition, mineral extractability, and antioxidant capacity of six date palm varieties grown in Sudan. The results showed that Sudanese date varieties contained significantly different (P < 0.05) amounts of moisture, ash, fiber, oil, and carbohydrates, but have almost similar amounts of protein. Moreover, results revealed that date varieties contained significantly varied (P < 0.05) amounts of total polyphenols and total flavonoids, which ranged between 35.82 and 99.34 mg gallic acid equivalent/100 g and 1.74–3.39 mg catechin equivalent/100 g, respectively. The antioxidant activities of the studied date varieties were as follows: ferric-reducing antioxidant power (FRAP) was within the range of 2.82–27.5 mmol/100 g, chelation of Fe2+ ion ranged from 54.31% to 94.98%, and scavenging of H2O2 ranged from 38.48% to 49.13%. There were many correlations (positive, negative, and weak) between antioxidant and mineral extractability of Sudanese date fruits. PMID:25473506

  11. Sulfate incorporation in monazite lattice: potential for dating the cycle of sulfur in metamorphic belts

    Science.gov (United States)

    Laurent, Antonin; Seydoux-Guillaume, Anne-Magali; Duchene, Stéphanie; Bingen, Bernard; Bosse, Valérie

    2016-04-01

    Monazite is a common accessory mineral in magmatic and metamorphic rocks that often shows complex chemical zoning at the μm- to nm-scale. The large number of cations that may be accommodated in its lattice, makes monazite particularly responsive to changes in the rock-forming minerals and fluid composition. Chemical zoning resulting from replacement or overgrowth may coincide, or not, with age zoning derived from U-Th-Pb isotopes. In this study, we focus on the potential for monazite to record both the redox condition of its crystalizing medium and an absolute U-Th-Pb isotopic age, during polyphase metamorphism in the Proterozoic province of Rogaland, S. Norway. The metamorphic evolution of several samples is derived from phase diagrams and the oxygen fugacity estimated from the FeO/Fe2O3 ratio measured by titration. Monazite grains were mapped at high spatial resolution for minor elements with electron microprobe, revealing convolute chemical zoning. Some of these zones yield appreciable content of S (up to 7000 ppm), accommodated following the Ca2+ + S6+ = REE3+ + P5+ substitution vector. The incorporation of sulfate in monazite has been subsequently investigated by TEM thanks to site specific FIB preparations. Besides, LA-ICP-MS U‑Pb isotopic ages of monazite grains show a remarkable correlation with the sulfate content. It is therefore possible to distinguish different generations of monazite based on their S-content. From our petrological study we conclude that sulfate-bearing monazite reflects incongruent melting of Fe-Cu-As sulfides under oxidizing conditions, coeval with biotite dehydration melting. Monazite may therefore be used to probe the presence of sulfur in anatectic melts from high-grade terrains at a specific point in time. This property can be used to investigate the mineralization potential of a given geological event within a larger orogenic framework.

  12. Characterization of mesoporous carbon prepared from date stems by H3PO4 chemical activation

    International Nuclear Information System (INIS)

    The present work was focused on the determination of texture, morphology, crystanillity and oxygenated surface groups characteristics of an activated carbon prepared from date stems. Chemical activation of this precursor at different temperatures (450, 550 and 650 °C) was adopted using phosphoric acid as dehydrating agent at (2/1) impregnation ratio. Fourier transform infrared spectroscopy study was carried out to identify surface groups in date stems activated carbons. The microscopic structure was examined by nitrogen adsorption at 77 K. The interlayer spacing (d200 and d100), stack height (Lc), stack width (La) and effective dimension L of the turbostratic crystallites (microcrystallite) in the date stems activated carbons were estimated from X-ray diffraction data (XRD). Results yielded a surface area, SBET, and total pore volume of 682, 1455, 1319 m2/g and 0,343, 1,045 and 0.735 cm3/g, for the carbon prepared at 450, 550 and 650 °C, respectively. Scanning electron microscopy exhibits a highly developed porosity which is in good agreement with the porous texture derived from gas adsorption data and these results confirm that the activated carbon is dominated by network of slit-shaped mesopores morphology and in some cases by varied micropores morphologies.

  13. Physico-Chemical Characteristics of Date Seed Oil Grown in Sudan

    Directory of Open Access Journals (Sweden)

    Rehab Salih Mahmoud Abdalla

    2012-01-01

    Full Text Available Problem statement: Studies were conducted on the physical-chemical properties of Sudanese date seed oil extracted from two date palm cultivars (Phoenix dactylifera L. ALBarakawi and Alqundeila. The extracted oil from ALBarakawi seeds weighed 6.833% w/w oil, Alqundeila oil extracted weighed 5.064% w/w. Approach: The physical properties of ALBarakawi oil were: viscosity: 17cp, refractive Index: 1.444, density: 0.9116 g cm-3 color: Within the range 1. 6-11.1 (red-yellow. For Alqundeila the physical properties were: viscosity: 20cp, refractive index: 1.458, density: 0.9174 g cm-3 color: 1.8-12.1 (red yellow. Results: The chemical properties were: Acid value 2.55, saponfication value 0.255 mg g-1, iodine value 71.12 gm I2/100 gm fat, peroxide value: 4.8 mg. Peroxide/Kgoil for ALBarakawi. For Alqundeila they were: acid value 2.47, saponfication value 0.267 mg g-1 and iodine value 83.31gm I2/100 gm fat, peroxide value: 7.4 mg Peroxide/Kgoil. In this study, High Performance Liquid Chromatography (HPLC was utilized for the identification and quantification of vitamin E in these samples. The content of vitamin E for ALBarakawi was 5.821 and 6.054 ppm for Alqundeila. For the fatty acid content in these oils, Gas Chromatography-Mass Spectrometry (GC-MS was used. The constituents of fatty acids (calculated % relative to total fatty acid constituents in ALBarakawi were: Saturated lauric acid 37.10%, palmitic acid: 9.24%, Stearic acid 1.71%, Unsaturated fatty acids: Linoleic acid (Omega-6 4.33%, Oleic acid (Omega-9 32.66%. For Alqundeila, the found fatty acids were: Saturated lauric acid o.11%, Palmitic acid: o.42%, Stearic acid 46.93%. Conclusion/Recommendations: The elements types and contents in these oils were: Iron 0.27 ppm, Magnesium 0.204 ppm, Sodium 60 ppm, Potassium 470 ppm, Calcium 25 ppm, Selenium 34.4 ppb for ALBarakawi. The contents of these elements in Alqundeila were: iron 0.27 ppm Magnesium 0.07 ppm, Potassium 2.3 ppm, Selenium 12.6 ppb. The

  14. Topics in Chemical Instrumentation: Cl. Thermoluminescence. Part III. Application to Archeological Dating.

    Science.gov (United States)

    Manche, Emanuel P.; Ewing, Galen W., Ed.

    1979-01-01

    Thermoluminescence and its application to archeological dating are considered in this article. Descriptions are given of the method, the required doses, absolute and relative dating, complications, and the relation of this type of dating to other methods. (SA)

  15. U-Pb dating by zircon dissolution method using chemical abrasion

    Energy Technology Data Exchange (ETDEWEB)

    Takehara, Lucy, E-mail: lucytakehara@gmail.com.br [Servico Geologico do Brasil (CPRM), Brasilia, DF (Brazil); Chemale Junior, Farid [Universidade de Brasilia (UnB), Brasilia, DF (Brazil). Inst. de Geociencias. Lab. de Geocronologia; Hartmann, Leo A. [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Inst. de Geociencias; Dussin, Ivo A.; Kawashita, Koji [Universidade de Sao Paulo (USP), SP, (Brazil). Centro de Pesquisa Geocronologicas

    2012-06-15

    Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-Multi Collector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3 +- 4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using {sup 235}U-{sup 205}Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7 +- 1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I - 416.75 +- 1.3 Ma; Temora II - 416.78 +- 0.33 Ma) and established as 416 +- 0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. (author)

  16. U-Pb dating by zircon dissolution method using chemical abrasion

    International Nuclear Information System (INIS)

    Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-Multi Collector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3 +- 4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using 235U-205Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7 +- 1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I - 416.75 +- 1.3 Ma; Temora II - 416.78 +- 0.33 Ma) and established as 416 +- 0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. (author)

  17. Ciprofloxacin adsorption from aqueous solution onto chemically prepared carbon from date palm leaflets

    Institute of Scientific and Technical Information of China (English)

    El-Said Ibrahim El-Shafey; Haider Al-Lawati; Asmaa Soliman Al-Sumri

    2012-01-01

    A chemically prepared carbon was synthesized from date palm leaflets via sulphuric acid carbonization at 160℃.Adsorption of ciprofloxacin (CIP) from aqueous solution was investigated in terms of time,pH,concentration,temperature and adsorbent status (wet and dry).The equilibrium time was found to be 48 hr.The adsorption rate was enhanced by raising the temperature for both adsorbents,with adsorption data fitting a pseudo second-order model well.The activation energy,Ea,was found to be 17 kJ/mol,indicating a diffusion-controlled,physical adsorption process.The maximum adsorption was found at initial pH 6.The wet adsorbent showed faster removal with higher uptake than the dry adsorbent,with increased performance as temperature increased (25-45℃ ).The equilibrium data were found to fit the Langmuir model better than the Freundlich model.The thermodynamic parameters showed that the adsorption process is spontaneous and endothermic.The adsorption mechanism is mainly related to cation exchange and hydrogen bonding.

  18. Physico-Chemical Characteristics and Total Quality of Date Palm Varieties Grown in the Southern of Tunisia

    Directory of Open Access Journals (Sweden)

    Abdessalem Mrabet

    2008-01-01

    Full Text Available The date palm, Phoenix dactylifera, is a palm extensively cultivated for its edible fruit. The chemical composition and the water content of ten Tunisian date varieties were determined. For all analysis, the Deglet Nour variety was taken as reference. Compositional analysis showed that the littoral varieties were very rich in reducing sugars (26 to 51% than Deglet Nour which was rich in sucrose (54%. The relative results of the moisture content showed that the littoral varieties were classified as soft dates. The vitamin C analysis showed that the littoral varieties were very rich in this compound (24 to 46 mg/100 g than Deglet Nour (1.12 mg/100 g. The mineral analysis showed that the littoral dates were relatively rich in potassium (283 to 733 mg/100 g and presented a weak content in sodium (0.06 to 0.09 mg/100 g.

  19. Exploitation of chemical profiles by conjugate variable analysis: application to the dating of a tropical ice core (Nevado Illimani, Bolivia)

    Science.gov (United States)

    Gay, M.; De Angelis, M.; Lacoume, J.-L.

    2013-06-01

    Ice core dating is a key parameter for the interpretation of the ice archives. However, the relationship between ice depth and age can generally not be easily established and requires to combine a large number of investigations and/or modeling effort. This paper presents a new approach of ice core dating based on conjugate variable (depth and spatial frequency) analysis of chemical profiles. The relationship between the depth of a given ice layer and the date it was deposited is determined using ion concentration depth profiles obtained along a one hundred-meters deep ice core recovered in the summit area of the Nevado Illimani (6350 m a.s.l.), located in the Eastern Bolivian Andes (16°37' S, 67°46' W). The results of Fourier conjugate analysis and wavelet tranforms are first compared. Both methods are applied to nitrate concentration depth profile. The resulting chronologies are checked by comparison with the multi-proxy year-by-year dating published by de Angelis et al. (2003) and with volcanic tie points, demonstrating the efficiency of Fourier conjugate analysis when tracking the natural variability of chemical proxies. The Fourier conjugate analysis is then applied to concentration depth profiles of seven other ions thus providing information on the suitability of each of them for dating studies of tropical Andean ice cores.

  20. U-Pb dating by zircon dissolution method using chemical abrasion

    Directory of Open Access Journals (Sweden)

    Lucy Takehara

    2012-06-01

    Full Text Available Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-MultiCollector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3±4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using 235U-205Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7±1.8 Ma (error 0.43 % based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I – 416.75±1.3 Ma; Temora II – 416.78±0.33 Ma and established as 416±0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error Este trabalho apresenta a técnica de abrasão química em zircões do padrão Temora II aplicada em datação de U-Pb por Dissolução Isotópica e Espectrometria de Massa por Ionização Térmica, método DI-ESIT. O emprego deste método tem como princípio diminuir os efeitos da perda secundária de Pb radiogênico antes da dissolução. Em primeira instância, os zircões foram analisados pelo método in situ com uso de Microssonda Laser acoplada a um Espectrômetro de Massa Multicoletor com Plasma Acoplado Indutivamente (MC-ICP-MS, cujo objetivo foi identificar os grãos de zircão de fase de cristalização simples sem sobrecrescimento. Nove cristais de zircão analisados com microssonda a

  1. Chemical Analysis of Different Parts of Date Palm (Phoenix dactylifera L.) Using Ultimate, Proximate and Thermo-Gravimetric Techniques for Energy Production

    OpenAIRE

    Ramadan A. Nasser; Salem, Mohamed Z.M.; Salim Hiziroglu; Hamad A. Al-Mefarrej; Ahmed S. Mohareb; Manawwer Alam; Aref, Ibrahim M.

    2016-01-01

    The objective of the study was to analyze chemical structure of date palm (Phoenix dactylifera L.) by employing ultimate, proximate and thermo-gravimetric techniques. Samples from different anatomical parts of date palm, namely trunk, frond base, frond midrib, leaflets, coir, fruit stem, date stone, and fruit empty bunches were considered for the experiments. Based on the findings in this work palm leaflet samples gave the highest amount of extractives content (32.9%), followed by date palm s...

  2. Irradiation of dates: insect disinfestation, microbial and chemical assessments, and use of thermoluminescence technique

    International Nuclear Information System (INIS)

    Irradiation of dates (Khalas variety) at 0.9 kGy was sufficient to eliminate single insect infestation (Oryzaephilus surinamensis) and mixed infestation (O. surinamensis and Tribolium castaneum), whereas 0.3 kGy was effective only in controlling single infestation. Sensory properties were not affected but irradiation contributed to some reduction in microbial counts immediately after irradiation and counts remained low till the end of 6 months storage period. All sugars were significantly reduced immediately after irradiation but they increased gradually with increasing storage time. Thermoluminescence (TL) technique was useful in discriminating between irradiated and unirradiated dates during the entire storage period but was less sensitive as far as the dose estimation is concerned

  3. Irradiation of dates: insect disinfestation, microbial and chemical assessments, and use of thermoluminescence technique

    Energy Technology Data Exchange (ETDEWEB)

    Al-Kahtani, Hassan A.; Abu-Tarboush, Hamza M.; Ahmed, Mohamed A.; Bajaber, Adnan S. [Food Science and Nutrition Department, College of Agriculture, King Saud University, Riyadh (Saudi Arabia); Al-Dryhim, Yousif N.; Adam, El-Shami E. [Plant Protection Department, College of Agriculture, King Saud University, Riyadh (Saudi Arabia); El-Mojaddidi, Mohamed A. [King Faisal Specialist Hospital and Research Center, Riyadh (Saudi Arabia)

    1998-08-01

    Irradiation of dates (Khalas variety) at 0.9 kGy was sufficient to eliminate single insect infestation (Oryzaephilus surinamensis) and mixed infestation (O. surinamensis and Tribolium castaneum), whereas 0.3 kGy was effective only in controlling single infestation. Sensory properties were not affected but irradiation contributed to some reduction in microbial counts immediately after irradiation and counts remained low till the end of 6 months storage period. All sugars were significantly reduced immediately after irradiation but they increased gradually with increasing storage time. Thermoluminescence (TL) technique was useful in discriminating between irradiated and unirradiated dates during the entire storage period but was less sensitive as far as the dose estimation is concerned.

  4. Dating gasoline releases using ground-water chemical analyses: Case studies

    International Nuclear Information System (INIS)

    This paper presents case studies where geochemical data were analyzed in spatial and temporal relation to documented gasoline releases at typical service station sites. In particular, the authors present ground-water analytical data for sites where (1) the date of the gasoline release is known with a good degree of confidence, (2) the release is confined to a relatively short period of time so as to be considered essentially instantaneous, (3) antecedent geochemical condition are known or can be reasonably expected to have been either unaffected by previous hydrocarbon impacts or minor in comparison to known release events, and (4) where geologic materials can be classified as to structure and composition. The authors' intent is to provide empirical data regarding the hydrogeological fate of certain gasoline components, namely the compounds benzene, toluene, ethylbenzene and xylene isomers (BTEX) and methyl-tertiary-butyl ether (MTBE). Particular emphasis is placed on analysis of gasoline weathering as a means of comparing releases in given hydrogeologic environments. Trends seen in a variety of comparative hydrocarbon compound ratios may provide a basis for evaluating relative release dates

  5. Chemical techniques to extract organic fractions from fossil bones for accurate 14C dating

    International Nuclear Information System (INIS)

    We examined different concentrations of HCl, such as 0.4, 0.6, 0.8, 1.0 and 1.2 M, for decalcification of fossil bones and different times of 0.1 M NaOH treatment on collagens to determine the best conditions for purifying collagen through extraction of humic contaminants, and compared the alkali treatment method with the XAD-2 treatment method for several types of fossils. The yield of acid-insoluble bone fractions did not change over the range from 0.4 to 1.0 M HCl and decreased suddenly with 1.2 M HCl on decalcification, and the 14C ages of the extracted gelatins from the five decalcified fractions were unchanged, suggesting that 14C ages as those of the XAD-purified hydrolysates. The NaOH-treatment time should be less than several hours to avoid a loss of collagen. The fossil bones used are relatively well-preserved, but the alkali treatment could bring about a lot of loss of organic bone proteins for poorly-preserved bones. The XAD-2 treatment method is effective for accurate radiocarbon dating of fossil bones, if the XAD-2 resin is completely pre-cleaned

  6. U-Pb zircon in situ dating with LA-MC-ICP-MS using a mixed detector configuration

    Energy Technology Data Exchange (ETDEWEB)

    Chemale Junior, Farid, E-mail: fchemale@unb.br [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Geociencias; Kawashita, Koji; Dussin, Ivo A. [Universidade de Sao Paulo (USP), SP (Brazil). Centro de Pesquisas Geocronologicas; Avila, Janaina N. [Australian National University, Canberra, (Australia). Research School of Earth Sciences; Justino, Dayvisson; Bertotti, Anelise [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Curso de Pos-Graduacao em Geociencias

    2012-06-15

    The LA-MC-ICP-MS method applied to U-Pb in situ dating is still rapidly evolving due to improvements in both lasers and ICP-MS. To test the validity and reproducibility of the method, 5 different zircon samples, including the standard Temora-2, ranging in age between 2.2 Ga and 246 Ma, were dated using both LA-MC-ICP-MS and SHRIMP. The selected zircons were dated by SHRIMP and, after gentle polishing, the laser spot was driven to the same site or on the same zircon phase with a 213 nm laser microprobe coupled to a multi-collector mixed system. The data were collected with a routine spot size of 25 {mu}m and, in some cases, of 15 and 40 {mu}m. A careful cross-calibration using a diluted U-Th-Pb solution to calculate the Faraday reading to counting rate conversion factors and the highly suitable GJ-1 standard zircon for external calibrations were of paramount importance for obtaining reliable results. All age results were concordant within the experimental errors. The assigned age errors using the LA-MC-ICP-MS technique were, in most cases, higher than those obtained by SHRIMP, but if we are not faced with a high resolution stratigraphy, the laser technique has certain advantages. (author)

  7. U-Pb zircon in situ dating with LA-MC-ICP-MS using a mixed detector configuration

    International Nuclear Information System (INIS)

    The LA-MC-ICP-MS method applied to U-Pb in situ dating is still rapidly evolving due to improvements in both lasers and ICP-MS. To test the validity and reproducibility of the method, 5 different zircon samples, including the standard Temora-2, ranging in age between 2.2 Ga and 246 Ma, were dated using both LA-MC-ICP-MS and SHRIMP. The selected zircons were dated by SHRIMP and, after gentle polishing, the laser spot was driven to the same site or on the same zircon phase with a 213 nm laser microprobe coupled to a multi-collector mixed system. The data were collected with a routine spot size of 25 μm and, in some cases, of 15 and 40 μm. A careful cross-calibration using a diluted U-Th-Pb solution to calculate the Faraday reading to counting rate conversion factors and the highly suitable GJ-1 standard zircon for external calibrations were of paramount importance for obtaining reliable results. All age results were concordant within the experimental errors. The assigned age errors using the LA-MC-ICP-MS technique were, in most cases, higher than those obtained by SHRIMP, but if we are not faced with a high resolution stratigraphy, the laser technique has certain advantages. (author)

  8. Chemical characterization and 210Pb dating in wetland sediments from the Nhecolandia Pantanal Pond, Brazil

    International Nuclear Information System (INIS)

    Pantanal, located in the central region of South America, is recognized as one of the world's largest freshwater wetlands. In order to verify possible changes in this environment, a study was undertaken in Nhecolandia Pantanal, Mato Grosso do Sul State, Brazil. Two sediment cores from the Salina do Meio pond (SM1 and SM2) and one core from a small flood land named Ba (B5) were collected in 2001. The elements As, Ba, Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb, Zn and Zr were determined by instrumental neutron activation analysis (INAA). Cluster and factorial analysis were applied to the chemical data. The sedimentation rate in the SM2 core was determined by 210Pb method and the mean value found was 0.61 cm x y-1. The results obtained in the present study showed that recent geochemical processes such as desorption, precipitation and dissolution can contribute for the high water alkalinity and salinity in the saline ponds. (author)

  9. Chemical abrasion-SIMS (CA-SIMS) U-Pb dating of zircon from the late Eocene Caetano caldera, Nevada

    Science.gov (United States)

    Watts, Kathryn E.; Coble, Matthew A.; Vazquez, Jorge A.; Henry, Christopher D.; Colgan, Joseph P.; John, David A.

    2016-01-01

    Zircon geochronology is a critical tool for establishing geologic ages and time scales of processes in the Earth's crust. However, for zircons compromised by open system behavior, achieving robust dates can be difficult. Chemical abrasion (CA) is a routine step prior to thermal ionization mass spectrometry (TIMS) dating of zircon to remove radiation-damaged parts of grains that may have experienced open system behavior and loss of radiogenic Pb. While this technique has been shown to improve the accuracy and precision of TIMS dating, its application to high-spatial resolution dating methods, such as secondary ion mass spectrometry (SIMS), is relatively uncommon. In our efforts to U-Pb date zircons from the late Eocene Caetano caldera by SIMS (SHRIMP-RG: sensitive high resolution ion microprobe, reverse geometry), some grains yielded anomalously young U-Pb ages that implicated Pb-loss and motivated us to investigate with a comparative CA and non-CA dating study. We present CA and non-CA 206Pb/238U ages and trace elements determined by SHRIMP-RG for zircons from three Caetano samples (Caetano Tuff, Redrock Canyon porphyry, and a silicic ring-fracture intrusion) and for R33 and TEMORA-2 reference zircons. We find that non-CA Caetano zircons have weighted mean or bimodal U-Pb ages that are 2–4% younger than CA zircons for the same samples. CA Caetano zircons have mean U-Pb ages that are 0.4–0.6 Myr older than the 40Ar/39Ar sanidine eruption age (34.00 ± 0.03 Ma; error-weighted mean, 2σ), whereas non-CA zircons have ages that are 0.7–1.3 Myr younger. U-Pb ages do not correlate with U (~ 100–800 ppm), Th (~ 50–300 ppm) or any other measured zircon trace elements (Y, Hf, REE), and CA and non-CA Caetano zircons define identical trace element ranges. No statistically significant difference in U-Pb age is observed for CA versus non-CA R33 or TEMORA-2 zircons. Optical profiler measurements of ion microprobe pits demonstrate consistent depths of ~ 1.6

  10. Direct Dating and Physico-Chemical Analyses Cast Doubts on the Coexistence of Humans and Dwarf Hippos in Cyprus.

    Directory of Open Access Journals (Sweden)

    Antoine Zazzo

    Full Text Available In the Mediterranean, the island dwarf megafaunas became extinct around the end of the Pleistocene, during a period of rapid and global climate change. In Cyprus, this coincided with the first human presence on the island, as attested by the rock shelter of Akrotiri-Aetokremnos where an Epipaleolithic anthropogenic layer (stratum 2 was found overlying a massive accumulation of pygmy hippopotamus (Phanourios minor (Desmarest, 1822 [Boekschoten and Sondaar, 1972] bones (stratum 4. The relationship between the two layers is highly controversial and the role played by humans in hippo extinction remains fiercely debated. Here, we provide new, direct radiocarbon and physico-chemical analyses on calcined bones which elucidates the complex depositional history of the assemblage. Bone turquoise was identified using micro-PIXE analysis and depth-profiling together with Vis spectroscopy, demonstrating that these bones were not freshly burned. Bayesian modeling of the radiocarbon dates indicates that stratum 4 accumulated during the first half of the 13th mill cal BP and that calcination occurred several hundred years later. We conclude that accumulation occurred naturally during the beginning of the Younger Dryas and that Epipalaeolithic visitors subsequently used the bones as fuel, starting from the mid-13th mill cal BP. At that time, dwarf hippos were probably already extinct or at least highly endangered. Our results shed new light on the possible causes of hippo extinction, on the subsequent introduction of the wild boar and on the earliest occupation of the island by humans.

  11. Determination of PAH sources in dated sediments from Green Bay, Wisconsin, by a chemical mass balance model.

    Science.gov (United States)

    Su, M C; Christensen, E R; Karls, J F

    1998-01-01

    Six sediment cores were collected from Green Bay, Wisconsin, in order to identify possible sources of polycyclic aromatic hydrocarbons (PAHs) by a chemical mass balance (CMB) model. The cores which were obtained in 1995 had total PAH concentrations between 8.04 and 0.460 ppm. 210Pb and 137Cs dating was used to determine historical trends of PAH inputs, and elemental carbon particle analysis was done to characterize particles from combustion of coal, wood and petroleum. The results show that coke burning, highway dust, and wood burning are likely sources of PAHs to Green Bay. The contribution of coke oven emissions (CB) for the Green Bay cores is in the range of 5 to 90%. The overall highway dust (HWY) contribution is between 5 and 70%. There is a maximum (approximately 67%) contribution of HWY around 1988 which is in agreement with the historical US petroleum consumption. The wood burning (WB) contribution is between 1 to 30%, except in core GB-A where a maximum (approximately 50%) is found around 1994. The average relative errors of measurement for x2 equal to the number of degrees of freedom, are 52.5, 56.2, 36.2, 52.3, and 42.8 (df = 3) for the Green Bay cores A, B, C, E, and F, respectively. The sums of the contribution factors are less than one, indicating gain of inert biological or other bulk material between source and receptor. The results of carbon particles for Green Bay core D show that coal, oil, and wood burning are consistent with the CMB modeling results. PMID:15093306

  12. Chemical composition and pulping of date palm rachis and Posidonia oceanica--a comparison with other wood and non-wood fibre sources.

    Science.gov (United States)

    Khiari, R; Mhenni, M F; Belgacem, M N; Mauret, E

    2010-01-01

    In the present paper, the valorisation of two residues: Posidonia oceanica and date palm rachis was investigated. First, their chemical composition was studied and showed that they present amounts of holocellulose, lignin and cellulose similar to those encountered in softwood and hardwood. Extractives in different solvents and ash contents are relatively high. Moreover, ash composition assessment showed that silicon is the major component (17.7%) for P. oceanica. The high ash quantity and the low DP (about 370) may be considered as serious disadvantages of P. oceanica, in the pulping and papermaking context. Oppositely, the properties of rachis date palm and those of the ensuing pulp, obtained from a classical soda-anthraquinone cooking, demonstrated the suitability of this agricultural by-product for papermaking. Preliminary tests conducted on unrefined pulp suspensions and handsheets from date palm rachis in terms of freeness, Water Retention Value and mechanical properties allowed confirming the good quality of date palm rachis fibres. PMID:19766481

  13. Chemical Analysis of Different Parts of Date Palm (Phoenix dactylifera L. Using Ultimate, Proximate and Thermo-Gravimetric Techniques for Energy Production

    Directory of Open Access Journals (Sweden)

    Ramadan A. Nasser

    2016-05-01

    Full Text Available The objective of the study was to analyze chemical structure of date palm (Phoenix dactylifera L. by employing ultimate, proximate and thermo-gravimetric techniques. Samples from different anatomical parts of date palm, namely trunk, frond base, frond midrib, leaflets, coir, fruit stem, date stone, and fruit empty bunches were considered for the experiments. Based on the findings in this work palm leaflet samples gave the highest amount of extractives content (32.9%, followed by date palm stone specimens with 31.5%. Cellulose content values of 32.8% and 47.5% were obtained for date palm stone and palm coir samples, respectively. Overall the hemicellulose contents of all samples were relatively similar to those of typical wood or non-wood lignocellulosic materials with the two exceptions of palm coir and palm leaflets. Both palm coir and palm leaflet specimens had 12.6% and 16.1% hemicellulose content. Volatile matter values of 74.3% and 87.5% were determined for leaflets and fruit empty bunch samples. The ash content of the samples ranged from 1.4% for date stone to 15.2% for palm leaflet samples. The thermal decomposition was completed below a temperature of 500 °C with an exception of those samples taken from palm leaflets. Taken together the data indicate that date palm stone and palm coir revealed could be more viable for renewable energy production than the other specimens considered in this work.

  14. Chemical Composition of Date-Pits and Its Potential for Developing Value-Added Product - a Review

    Directory of Open Access Journals (Sweden)

    Hossain Mohammad Zakir

    2014-12-01

    Full Text Available Moisture, protein, oil and carbohydrate contents of date-pits varied from 3.1-12.5, 2.3-6.9, 5.0-12.5 and 70.9-86.9 g/100 g date-pits, respectively. BET-monolayer (i.e. strongly bound moisture content, solids-melting peak (at moisture: 6.7 g/100 g date-pits, and melting point of oil were 4.3 g/100 g dry-solids, 106oC, and 1.8oC, respectively. The major fatty acids were lauric, myristic, palmitic, stearic, oleic, and linoleic acids and polyphenol content varied from 21.0-62.0 mg/g date-pits depending on the varieties, types of solvent and temperature used for extraction. Date-pits showed effectives in animal and poultry feeds and it could be used as value added products, such as: dietary fibres, functional polysaccharides, caffeine-free drinks (similar to coffee, oil (biofuel or cooking oil, and other functional or medicinal products. Date-pits powder and activated carbon from date–pits showed effective in purifying water by removing different types of pollutants, such as heavy metals, boron, dyes, phenolic compounds, and pesticides. Date-pits also showed effective to be used as ingredient for composed, biomass, and fermentation processes.

  15. Ion microprobe U-Pb dating and REE abundance of biogenic apatite

    Science.gov (United States)

    Sano, Y.; Terada, K.; Ueki, S.

    2001-12-01

    If the direct U-Pb dating of a fossil itself is possible, the method could have great impact on stratigraphic studies in establishing the absolute chronology of sedimentary sequences. Micro fossil ?conodont? are candidates for this purpose since they consist of apatite (Ca2(PO5)3 (F,Cl,OH)), which would uptake U, Th and Pb after sedimentation no longer than a few million years and is supposed to remain closed to U and Pb under relatively low effective closure temperature. We report here results of direct ion microprobe U-Th-Pb dating of two conodonts; Trichognathus from Kinderhookian stage of Mississippian sedimentary sequence from Illinois Basin region in North America and Panderodus from a Llandoverian sedimentary sequence on Langkawi Island, northern Malaysia. Secondary purpose of the study is to indicate in situ analysis of all REE on the same spots of U-Pb measurements. Samples were cast into epoxy resin discs with a few grains of standard apatite, PRAP, derived from an alkaline rock of Prairie Lake circular complex in the Canadian Shield and polished until they were exposed through their mid-sections. U, Th and REE abundances, and Pb isotopic compositions were measured by using SHRIMP installed at Hiroshima University. Thirteen spots on Trichognathus yield a 238U/206Pb isochron age of 323+/-36 Ma, which is consistent with the depositional and early diagenetic ages. Fifteen spots on Panderodus give 232Th/208Pb isochron age of 429+/-50 Ma, which is again comparable to an early Silurian. Shale-normalized REE of Trichognathus shows a broadly flat pattern from light to middle REE and a decrease from middle to heavy REE with negative anomalies of Ce and Eu. In contrast Panderodus indicates a concave-shape pattern with middle REE enrichment. These characteristics are probably due to a different formation environment as suggested by other workers.

  16. Chemical pretreatments for improving the radiocarbon dates of peats and organic silts in a gley podzol environment : Grahams Terrace, north Westland

    International Nuclear Information System (INIS)

    Radiocarbon dates obtained for peats and organic silts from the high rainfall/leaching environment of North Westland have been shown to conflict with known stratigraphic evidence by yielding anomalously young dates. This study examines the effectiveness of 14 chemical pretreatment methods, including classical humus fractionation of soil organic matter, hydrolysis with mineral acids (6 M HCl and 70% HNO3), and extraction of lipids and cellulose, in removing young carbon contaminants from peat and organic silt samples prior to radiocarbon assay. The criterion chosen for judging the effectiveness of a treatment in removing young contaminants is an increase in 14C age, with the assumption that contamination is largely due to young carbon. Chemical pretreatments were undertaken on peat and organic silt samples taken immediately above (5-0 cm) and below (0-5 cm) a layer of Kawakawa Tephra found at Grahams Terrace in North Westland. Radiocarbon dates, obtained by accelerator mass spectrometer (AMS), showed that most of the pretreatments and their extracts improved the 14C ages compared with untreated samples. The hydrolysis of peat and organic silt samples with 70% HNO3 and dating the resultant residue produced significantly increased 14C dates (c. 6000 years) with respect to untreated samples. The major conclusion from this study is that existing radiocarbon dates of 12,000 yr B.P. and older, on peats and organic silts from gley podzol environments, are contaminated by younger, less stable, more mobile carbon, such as fulvic and humic acid fractions. (author). 20 refs., 1 fig., 1 tab

  17. Chemical characterization and AMS radiocarbon dating of the binder of a prehistoric rock pictograph at Tadrart Acacus, southern west Libya

    Czech Academy of Sciences Publication Activity Database

    Mori, F.; Ponti, R.; Messina, A.; Flieger, Miroslav; Havlíček, Vladimír; Sinibaldi, M.

    2006-01-01

    Roč. 7, - (2006), s. 344-349. ISSN 1296-2074 Institutional research plan: CEZ:AV0Z50200510 Keywords : rock pictograph * libya n sahara * radiocarbon dating Subject RIV: EE - Microbiology, Virology Impact factor: 0.738, year: 2006

  18. The effect of black cumin (nigella sativa L) oil on the chemical and physical properties of date paste

    International Nuclear Information System (INIS)

    Date paste was manufactured with the addition of back cumin (Nigella Sativa L.) oil at 2 levels namely 0.2 and 0.4% using 2 methods (a) externally coating (on the surface) and (b) internally (mixed with the paste) and stored for three months at two temperatures (room and refrigeration temperature). Compared to the control samples, addition of oil to the date paste resulted in significantly (p=0.05) higher moisture content and water activity (aw) which was proportional to the concentration of oil in the samples. In spite of this the microbial growth was negligible (aw less than 0.6). The addition of oil neither significantly (p=0.05) affected the pH nor the acidity, but at room temperature there was stepwise increase in acidity during storage. There was a significant (p=0.05) decrease in the TSS of all the samples treated with the oil although there was a stepwise increase in TSS during storage at room temperature. The addition of oil has significantly increased the softness of the paste during storage proportional to the concentration, which was better at room temperature than at cold storage. The browning has significantly increased during storage especially at room temperature. It is observed that good quality data paste could be produced with the addition 0.4% of black cumin oil especially at the surface and stored at room temperature. (Author)

  19. Date Rape

    Science.gov (United States)

    ... Can I Help a Friend Who Cuts? Date Rape KidsHealth > For Teens > Date Rape Print A A ... en español Violaciones durante citas What Is Date Rape? When people think of rape , they might picture ...

  20. Using chemical, hydrologic, and age dating analysis to delineate redox processes and flow paths in the riparian zone of a glacial outwash aquifer-stream system

    Science.gov (United States)

    Puckett, L.J.; Cowdery, T.K.; McMahon, P.B.; Tornes, L.H.; Stoner, J.D.

    2002-01-01

    A combination of chemical and dissolved gas analyses, chlorofluorocarbon age dating, and hydrologic measurements were used to determine the degree to which biogeochemical processes in a riparian wetland were responsible for removing NO3- from groundwaters discharging to the Otter Tail River in west central Minnesota. An analysis of river chemistry and flow data revealed that NO3- concentrations in the river increased in the lower half of the 8.3 km study reach as the result of groundwater discharge to the river. Groundwater head measurements along a study transect through the riparian wetland revealed a zone of groundwater discharge extending out under the river. On the basis of combined chemical, dissolved gas, age date, and hydrologic results, it was determined that water chemistry under the riparian wetland was controlled largely by upgradient groundwaters that followed flow paths up to 16 m deep and discharged under the wetland, creating a pattern of progressively older, more chemically reduced, low NO3- water the farther one progressed from the edge of the wetland toward the river. These findings pose challenges for researchers investigating biogeochemical processes in riparian buffer zones because the progressively older groundwaters entered the aquifer in earlier years when less NO3- fertilizer was being used. NO3- concentrations originally present in the groundwater had also decreased in the upgradient aquifer as a result of denitrification and progressively stronger reducing conditions there. The resulting pattern of decreasing NO3- concentrations across the riparian zone may be incorrectly interpreted as evidence of denitrification losses there instead of in the upgradient aquifer. Consequently, it is important to understand the hydrogeologic setting and age structure of the groundwaters being sampled in order to avgid misinterpreting biogeochemical processes in riparian zones.

  1. Thermoluminescence dating

    International Nuclear Information System (INIS)

    The method of dating archaeological pottery specimens by thermoluminescence is described. Techniques for measuring the radiation dose within the pottery fabric and from the surrounding burial medium are discussed. Examples are given of dating projects. (U.K.)

  2. Radiocarbon Dating

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A

    2007-12-20

    Radiocarbon dating can be used to determine the age of objects that contain components that were once alive. In the case of human remains, a radiocarbon date can distinguish between a crime scene and an archeological site. Documents, museum artifacts and art objects can be dated to determine if their age is correct for the historical context. A radiocarbon date does not confirm authenticity, but it can help identify a forgery.

  3. Radiometric dating

    International Nuclear Information System (INIS)

    The paper on radiometric dating is a chapter in a handbook of Holocene Palaeoecology and Palaeohydrology. This chapter is part of a section on dating methods. Radiocarbon dating is discussed with respect to the apparent ages of lake sediments, seawater, sea creatures and plants. Isotope dating methods for the late Holocene deposits involving 210Pb, 137Cs, sup(239, 240)Pu, 241Am, 32Si and 39Ar are also described. (U.K.)

  4. Dating Violence

    Science.gov (United States)

    Stader, David L.

    2011-01-01

    Dating violence is a form of student-on-student victimization and is a serious school safety issue. Research indicates that at a minimum, 10 percent of high school students are victims of dating violence in one form or another. Among female high school students that date, some data indicate that as many as 30 percent may be victims of dating…

  5. Effect of ultrafiltration process on physico-chemical, rheological, microstructure and thermal properties of syrups from male and female date palm saps.

    Science.gov (United States)

    Makhlouf-Gafsi, Ines; Baklouti, Samia; Mokni, Abir; Danthine, Sabine; Attia, Hamadi; Blecker, Christophe; Besbes, Souhail; Masmoudi, Manel

    2016-07-15

    This study investigates the effect of the ultrafiltration process on physicochemical, rheological, microstructure and thermal properties of syrups from male and female date palm sap. All the studied syrups switched from pseudoplastic rheological behaviour (n=0.783) to Newtonian behaviour (n∼1) from 10 to 50 °C respectively and present similar thermal profiles. Results revealed that the ultrafiltration process significantly affects the rheological behaviour of the male and female syrups. These differences on rheological properties are attributed to the variation of chemical composition between sap and sap permeate syrups. Furthermore, the effect of temperature on viscosity of the syrups was investigated during heating and cooling processes at the same shear rate (50s(-1)). This study provides idea of the stability of the syrup by evaluating the area between heating and cooling curves. Actually, the syrup prepared from male sap permeate is the most stable between the four studied syrups. PMID:26948603

  6. Chemical and U-Pb dating investigation of zircons from alnöites on Malaita, Solomon Islands: evidence for prolonged kimberlite-type magmatic activity

    Science.gov (United States)

    Simonetti, A.; Neal, C. R.

    2009-12-01

    The Solomon Islands chain is located in an area dominated by the Ontong Java Plateau (OJP). The island of Malaita formed at the obducted leading edge of the OJP and is geologically distinct from the islands to the west. Occurrences of pipe-like bodies of alnöite outcrop within limestones and mudstones in northern Malaita and have been seismically imaged offshore within the OJP. The Malaita alnöite is silica-undersaturated and contains a rich and varied suite of peridotite xenoliths and megacrysts (clinopyroxene, garnet, ilmenite, phlogopite, and minor zircon). The alnöite and associated megacrysts have been the focus of detailed chemical and radiogenic isotope investigations but the exact age of alnöite emplacement remains debatable. Previously reported ages for minerals associated with the Malaita alnöites include an Ar-Ar date of 34 Ma for phlogopite from a mantle xenolith, and a single 206Pb/238U date of 33.9 Ma obtained from a single zircon megacryst. Here we report on a detailed chemical (major and trace element) and U-Pb age investigation of zircon crystals recovered from rivers in the Aluta, Kwainale, and Faufaumela regions of central Malaita. The major element (SiO2, ZrO2, and HfO2) composition and back scattered electron (BSE) imaging of mm- to cm-sized zircons from the three locations were conducted by electron microprobe analysis. The data reveal a variation in the Zr/Hf ratio (45 to 57) for zircons from the Aluta area, whereas this ratio is relatively uniform in most zircons from Kwainale (Zr/Hf 45 to 48). Of importance, the BSE imaging reveals the homogeneous nature of the grains and the lack of inherited components. Trace element compositions of the zircon crystals were obtained by laser ablation (LA)-ICP-MS and these reveal similar chondrite-normalized REE patterns at variable enrichment levels for all grains analyzed; these patterns along with the U, Th, and Pb contents are similar to those documented for mantle-derived zircons formed within

  7. U-Th-Pb systematics of some granitoids from the northeastern Yilgarn Block, Western Australia and implications for uranium source rock potential

    International Nuclear Information System (INIS)

    The Mount Boreas-type granite and spatially associated syenitic granitoid of Western Australia yield Pb-Pb ages of 2370 +- 100 Ma and 2760 +- 210 Ma, respectively. Th-Pb ages, although less precise, are concordant with these ages, and therefore the apparent ages are interpreted to be the crystallisation ages for these two units. U-Pb ages are variable and for the most part anomalously old, which suggests a Cainozoic uranium loss. However, this loss is generally small (3μg/g); therefore, neither granitoid in its fresh state provides a good source for nearby calcrete-hosted uranium deposits. The possibility remains that the Mount Boreas-type granite that has been completely weathered during the Tertiary could have been a source for the calcrete-type uranium deposits in W.A. Although the Mount Boreas-type granite is highly fractionated, it does not bear a strong geochemical imprint of a sedimentary precursor. This feature contrasts it with apparently fresh granitoids from other parts of the world that have lost large amounts of uranium (approx. 20μg/g) and are associated with large roll-type and other low temperature-type uranium deposits

  8. Thermoluminescence dating

    International Nuclear Information System (INIS)

    The influence of radioactive disequilibrium on TL age accuracy is further checked. TL dating applied to pottery sets the beginning of the neolithic period in Lower Austria in the first half of 6th millenium B.C. (orig.)

  9. 2.9, 2.36, and 1.96 Ga zircons in orthogneiss south of the Red River shear zone in Viet Nam: evidence from SHRIMP U-Pb dating and tectonothermal implications

    Science.gov (United States)

    Nam, Tran Ngoc; Toriumi, Mitsuhiro; Sano, Yuji; Terada, Kentaro; Thang, Ta Trong

    2003-05-01

    Orthogneissic rocks coexisting with migmatites and containing small amphibolite lenses are exposed in the center of the metamorphic belt which runs parallel to the Day Nui Con Voi-Red River shear zone in northern Viet Nam. The orthogneiss complex has given some radiogenic dates of Early Proterozoic and Late Archean, which are the oldest ages ever registered for the Southeast Asian continent. Zircon grains separated from three samples of the orthogneiss complex have been dated to establish the protolith age and the timing of high-grade tectonothermal events in the complex. Sixty-five SHRIMP U-Th-Pb analyses of these zircons define three age groups of 2.84-2.91, 2.36, and 1.96 Ga. The age groups correspond to three periods of zircon generation. The oldest ˜2.9 Ga cores indicate a minimum age for the protolith of the orthogneiss complex. Two younger generations (including ˜2.36 Ga outer-cores and ˜1.96 Ga rims) probably grew during later high-grade tectono-metamorphic events, which were previously suggested by K-Ar and 40Ar/ 39Ar cooling ages of ˜2.0 Ga for synkinematic hornblendes. An early thermal history of the orthogneiss complex has been constrained, including a primary magma-crystallization stage starting at ˜2.9 Ga, followed by two Early Proterozoic (˜2.36 and ˜1.96 Ga) high-grade tectonothermal events. The ca. 2.9 Ga protolith age of the orthogneiss complex documented in this study provides new convincing evidence for the presence of Archean rocks in Indochina, and clearly indicates that the crustal evolution of northern Viet Nam started as early as Late Archean time.

  10. Thermoluminescence dating

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) dating of sediments depends upon the acquisition and long term stable storage of TL energy by crystalline minerals contained within a sedimentary unit. This energy is stored in the form of trapped electrons and quartz sand is the most commonly used mineral employed in the dating process. Prior to the final depositional episode it is necessary that any previously acquired TL is removed by exposure to sunlight. After burial the TL begins to build up again at a rate dependent upon the radiation flux delivered by long-lived isotopes of uranium, thorium and potassium. The presence of rubidium and cosmic radiation generally play a lesser but contributory roll, and the total radiation dose delivered to the TL phosphor is modified by the presence of water. The period since deposition is therefore measured by determining the total amount of stored TL energy, the palaeodose (P), and the rate at which this energy is acquired, the annual radiation dose (ARD). TL dating may be applied to eolian, fluvial, coastal and in some cases, marine sediments. the technique is also successfully applied to volcanic materials and to a certain extent to archeological specimens

  11. Thermoluminescence dating

    Energy Technology Data Exchange (ETDEWEB)

    Price, D.M. [University of Wollongong, Wollongong, NSW (Australia). School of Geosciences

    1999-11-01

    Thermoluminescence (TL) dating of sediments depends upon the acquisition and long term stable storage of TL energy by crystalline minerals contained within a sedimentary unit. This energy is stored in the form of trapped electrons and quartz sand is the most commonly used mineral employed in the dating process. Prior to the final depositional episode it is necessary that any previously acquired TL is removed by exposure to sunlight. After burial the TL begins to build up again at a rate dependent upon the radiation flux delivered by long-lived isotopes of uranium, thorium and potassium. The presence of rubidium and cosmic radiation generally play a lesser but contributory roll, and the total radiation dose delivered to the TL phosphor is modified by the presence of water. The period since deposition is therefore measured by determining the total amount of stored TL energy, the palaeodose (P), and the rate at which this energy is acquired, the annual radiation dose (ARD). TL dating may be applied to eolian, fluvial, coastal and in some cases, marine sediments. the technique is also successfully applied to volcanic materials and to a certain extent to archeological specimens

  12. Dating deformation - Lifetimes of phases vs. lifetimes of crystals and pulsed motion along fault zones

    Science.gov (United States)

    Chakraborty, Sumit

    2016-04-01

    these rocks are the ages of peak of metamorphism in the presence of melt, rather than from the prograde path. When these information are combined with those from phase equilibria and geospeedometry, a systematic P-T-t history of the rocks may be constructed and as a result, a history of pulsed motion along the MCT may be obtained. Dates of rocks from the MCT zone itself, on the other hand, preserve one point in the P-T-t evolution. It can be shown that different isotopic systems (e.g. Lu-Hf in garnet vs. U-Th-Pb in monazites or zircons) preserve dates from different stages of this pulsed history and interpolating linearly between them to obtain rates of motion may give misleading results. Combination of both kinds of information with proper attention to the P-T history of the rocks yields the most internally consistent picture of motion along the fault zone. Ref: Anzckiewicz, R., Chakraborty, S., Dasgupta, S., Mukhopadhyay, D., Koltonik, K.: Timing, duration and inversion of prograde Barrovian metamorphism constrained by high resolution Lu-Hf garnet dating: A case study from the Sikkim Himalaya, NE India; Earth and Planetary Science Letters, Volume 407, Pages 70 - 81, DOI: 10.1016/j.eps1.2014.09.035

  13. Qualitative and quantitative spectro-chemical analysis of dates using UV-pulsed laser induced breakdown spectroscopy and inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Mehder, A O; Habibullah, Y B; Gondal, M A; Baig, Umair

    2016-08-01

    Laser Induced Breakdown Spectroscopy (LIBS) is demonstrated for the spectral analysis of nutritional and toxic elements present in several varieties of date fruit samples available in the Saudi Arabia market. The method analyzes the optical emission of a test sample when subjected to pulsed laser ablation. In this demonstration, our primary focus is on calcium (Ca) and magnesium (Mg), as nutritional elements, and on chromium (Cr), as a toxic element. The local thermodynamic equilibrium (LTE) condition was confirmed prior to the elemental characterization of date samples to ensure accuracy of the LIBS analysis. This was achieved by measuring parameters associated with the plasma, such as the electron temperature and the electron number density. These plasma parameters aid interpretation of processes such as ionization, dissociation, and excitation occurring in the plasma plume formed by ablating the date palm sample. The minimum detection limit was established from calibration curves that involved plotting the LIBS signal intensity as a function of standard date samples with known concentrations. The concentration of Ca and Mg detected in different varieties of date samples was between 187 and 515 and 35-196mgL(-1) respectively, while Cr concentration measured between 1.72 and 7.76mgL(-1). In order to optimize our LIBS system, we have studied how the LIBS signal intensity depends on the incident laser energy and the delay time. In order to validate our LIBS analysis results, standard techniques such as inductively coupled plasma mass spectrometry (ICP-MS) were also applied on an identical (duplicate) date samples as those used for the LIBS analysis. The LIBS results exhibit remarkable agreement with those obtained from the ICP-MS analysis. In addition, the finger print wavelengths of other elements present in date samples were also identified and are reported here, which has not been previously reported, to the best of our knowledge. PMID:27216665

  14. Lunar Science Conference, 5th, Houston, Tex., March 18-22, 1974, Proceedings. Volume 1 - Mineralogy and petrology. Volume 2 Chemical and isotope analyses. Organic chemistry. Volume 3 - Physical properties

    Science.gov (United States)

    Gose, W. A.

    1974-01-01

    Numerous studies on the properties of the moon based on Apollo findings and samples are presented. Topics treated include ages of the lunar nearside light plains and maria, orange material in the Sulpicius Gallus formation at the southwestern edge of Mare Serenitatis, impact-induced fractionation in the lunar highlands, igneous rocks from Apollo 16 rake samples, experimental liquid line of descent and liquid immiscibility for basalt 70017, ion microprobe mass analysis of plagioclase from 'non-mare' lunar samples, grain size and the evolution of lunar soils, chemical composition of rocks and soils at Taurus-Littrow, the geochemical evolution of the moon, U-Th-Pb systematics of some Apollo 17 lunar samples and implications for a lunar basin excavation chronology, volatile-element systematics and green glass in Apollo 15 lunar soils, solar wind nitrogen and indigenous nitrogen in Apollo 17 lunar samples, lunar trapped xenon, solar flare and lunar surface process characterization at the Apollo 17 site, and the permanent and induced magnetic dipole moment of the moon. Individual items are announced in this issue.

  15. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  16. Evolution of chemical and isotopic composition of inorganic carbon in a complex semi-arid zone environment: Consequences for groundwater dating using radiocarbon

    Science.gov (United States)

    Meredith, K. T.; Han, L. F.; Hollins, S. E.; Cendón, D. I.; Jacobsen, G. E.; Baker, A.

    2016-09-01

    Estimating groundwater age is important for any groundwater resource assessment and radiocarbon (14C) dating of dissolved inorganic carbon (DIC) can provide this information. In semi-arid zone (i.e. water-limited environments), there are a multitude of reasons why 14C dating of groundwater and traditional correction models may not be directly transferable. Some include; (1) the complex hydrological responses of these systems that lead to a mixture of different ages in the aquifer(s), (2) the varied sources, origins and ages of organic matter in the unsaturated zone and (3) high evaporation rates. These all influence the evolution of DIC and are not easily accounted for in traditional correction models. In this study, we determined carbon isotope data for; DIC in water, carbonate minerals in the sediments, sediment organic matter, soil gas CO2 from the unsaturated zone, and vegetation samples. The samples were collected after an extended drought, and again after a flood event, to capture the evolution of DIC after varying hydrological regimes. A graphical method (Han et al., 2012) was applied for interpretation of the carbon geochemical and isotopic data. Simple forward mass-balance modelling was carried out on key geochemical processes involving carbon and agreed well with observed data. High values of DIC and δ13CDIC, and low 14CDIC could not be explained by a simple carbonate mineral-CO2 gas dissolution process. Instead it is suggested that during extended drought, water-sediment interaction leads to ion exchange processes within the top ∼10-20 m of the aquifer which promotes greater calcite dissolution in saline groundwater. This process was found to contribute more than half of the DIC, which is from a mostly 'dead' carbon source. DIC is also influenced by carbon exchange between DIC in water and carbonate minerals found in the top 2 m of the unsaturated zone. This process occurs because of repeated dissolution/precipitation of carbonate that is dependent on

  17. Dating by C14

    International Nuclear Information System (INIS)

    This report summarizes the results of studies made with two assemblies for dating geological and archaeological objects with C14. The advantages and drawbacks of three ways of determining C14 activity in solid, liquid and gaseous substances are discussed. Data are given of the chemical preparation and cleaning of the gaseous carbon compounds ethane, acetylene and carbon dioxide, and the calculation of their C14 activity. The report assesses the mistakes that can be made in determining age by C14, and gives data for geological and archaeological objects in the Soviet Union. (author)

  18. In-situ chemical, U-Pb dating, and Hf isotope investigation of megacrystic zircons, Malaita (Solomon Islands): Evidence for multi-stage alkaline magmatic activity beneath the Ontong Java Plateau

    Science.gov (United States)

    Simonetti, Antonio; Neal, Clive R.

    2010-06-01

    Previous investigations of pipe-like intrusions of alnöite within northern Malaita (Solomon Islands) have detailed the chemical and isotopic nature of the alnöite and entrained megacrysts/xenoliths. Alnöite emplacement is poorly constrained since available ages include an Ar-Ar date of 34 Ma (phlogopite) from a mantle xenolith, and a 206Pb/238U date of 33.9 Ma for a zircon megacryst. Hence, we report chemical data, in-situ U-Pb age determinations and Hf isotope compositions for megacrystic zircons recovered from alnöite-derived, ilmenite-rich gravels in the Auluta, Kwainale, and Faufaumela rivers of Malaita. The Zr/Hf ratio (39 to 50) is variable for zircons from Auluta and Faufaumela, whereas it is relatively uniform (40 to 42) in most zircons from Kwainale. Chemical imaging reveals the homogeneous nature for all of the 16 grains analyzed. Trace element compositions obtained by LA-ICP-MS indicate parallel chondrite-normalized REE patterns at variable levels of enrichment; these patterns combined with their low abundances (< 1 to 10 ppm) of U, Th, and Pb confirm their mantle origin. In-situ U-Pb dating conducted by LA-ICP-MS (n = 94 analyses) define a total range in weighted mean (WM) 206Pb/238U ages between ∼ 35 and ∼ 52 Ma. The zircons from Auluta define a range of WM 206Pb/238U ages between 34.9 ± 2.0 Ma and 45.1 ± 2.5 Ma (2σ) that correlate negatively with Zr/Hf ratios and total REE contents. Conversely, the chemically homogeneous zircons from Kwainale define a uniform age spectrum yielding a WM 206Pb/238U age of 36.7 ± 0.5 Ma (2σ). In-situ Hf isotope analyses (n = 30) are uniform and define a WM 176Hf/177Hf value of 0.282933 ± 0.000013 (2σ), which is identical to the previously reported whole rock value for the Malaitan alnöite (0.282939 ± 0.000007). Correlations between ages and chemical compositions (i.e., Auluta zircons), and the uniform Hf isotope compositions are consistent with zircon formation from a common Ontong Java Plateau (OJP

  19. Improving Consistency in Laser Ablation Geochronology

    Science.gov (United States)

    Horstwood, Matt; Gehrels, George; Bowring, James

    2010-07-01

    Workshop on Data Handling in LA-ICP-MS U-Th-Pb Geochronology; San Francisco, California, 12-13 December 2009; The use of uranium-thorium-lead (U-Th-Pb) laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) geochronology involves rapid analysis of U-and Th-rich accessory minerals. It routinely achieves 1-2% precision for U-Th-Pb dates constituting detrital mineral age spectra and for dating igneous and metamorphic events. The speed and low setup and analysis cost of LA-ICP-MS U-Th-Pb geochronology has led to a proliferation of active laboratories. Tens of thousands of analyses are produced per month, but there is little agreement on how to transform these data into accurate U-Th-Pb dates. Recent interlaboratory blind comparisons of zircon samples indicate that resolvable biases exist among laboratories and the sources of bias are not fully understood. Common protocols of data reduction and reporting are essential for scientists to be able to compare and interpret these data accurately.

  20. Up-to-date concentrations of long-lived artificial radionuclides in the Tom and Ob rivers in the area influenced by discharges from Siberian chemical combine

    International Nuclear Information System (INIS)

    The Siberian Chemical Combine (SCC) is located in Seversk (formerly known as Tomsk-7) in the Tomsk Region of the Russian Federation. The main contribution of radionuclides in the SCC process water discharged into the Tom River was from the single-pass reactors, now removed from service (the last SCC reactor was shutdown on June 5, 2008). The data on the concentrations of 90Sr, 137Cs, 239,240Pu and other artificial radionuclides in water, bottom sediments and flood-plain soils of the Tom and Ob rivers from Tomsk to the confluence of the rivers, are presented and discussed. The results of measurements carried out after shutdown of the last SCC single-pass reactor indicated no radiologically significant consequences of SCC activities for the studied water environment compartments. Contemporary activity concentrations of long-lived artificial radionuclides 3H, 90Sr, 137Cs and 239,240Pu in river water were below the intervention levels established by current regulations of the Russian Federation for these radionuclides. The results of 3H analysis in water from the Tom and Samuska rivers demonstrated no inflow of contaminated formation water to surface water from the sites where liquid radioactive wastes of the SCC were injected below the surface. However, the density of flood-plain soil contamination by long-lived 137Cs in the area influenced by SCC liquid discharges was higher than regional technogenic background. There were local flood-plain areas contaminated not only by 137Cs, but also other gamma-emitters, such as 60Co and 152Eu.

  1. Thermoluminescence dating of dental enamel

    International Nuclear Information System (INIS)

    Thermoluminescent response of the synthetic hydroxylapatite was studied, this material being the fundamental inorganic constituent of dental enamel. In order to make an attempt at archaeological TL dating of teeth, a chemical deproteination procedure of enamel was established, and the pre-dose effects of separated mineral grains extracted from 100 to 6000 years old human teeth were investigated. (orig.)

  2. Uranium-lead dating of perovskite from the Afrikanda plutonic complex (Kola Peninsula, Russia) using LA-ICP-MS.

    Science.gov (United States)

    Reguir, E.; Camacho, A.; Yang, P.; Chakhmouradian, A. R.; Halden, N. M.

    2009-04-01

    ) The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology. Chem. Geol.,211, 47-69. Kramm, U., Kogarko, L.N., Kononova, V.A. and Vartiainen, H. (1993) The Kola alkaline province of the CIS and Finland. Lithos, 30, 33-44. Tera, F. and Wasserburg, G.J. (1972) U-Th-Pb systematics in three Apollo 14 basalts and the problem of initial Pb in lunar rocks. Earth Planet. Sci. Lett., 14, 281-304.

  3. Teen Dating Violence

    Science.gov (United States)

    ... dating violence prevention initiative seeks to reduce dating violence and increase healthy relationships in high-risk urban communities through comprehensive, multisector prevention. Division of Adolescent ...

  4. Radiocarbon dating of artworks

    OpenAIRE

    Krajcar Bronić, Ines; Horvatinčić, Nada; Barešić, Jadranka; Sironić, Andreja

    2015-01-01

    Absolute dating of artworks and cultural heritage objects is one of the most important issues in art history studies and essential for evaluating original art objects, differentiating between originals and later imitations and/or frauds and recognizing subsequent repairs and restauration works. The radiocarbon dating (14C dating) method is one of the most well-known radiometric methods of absolute dating, which can be applied for dating materials of biogenic origin, such as wood, charcoal, bo...

  5. Expiration Dates Matter

    Medline Plus

    Full Text Available ... For Consumers Home For Consumers Consumer Updates Expiration Dates Matter Share Tweet Linkedin Pin it More sharing ... video, FDA Pharmacist Ilisa Bernstein explains how expiration dates help determine if medicine is safe to use ...

  6. Expiration Dates Matter

    Medline Plus

    Full Text Available ... Products For Consumers Home For Consumers Consumer Updates Expiration Dates Matter Share Tweet Linkedin Pin it More ... Update video, FDA Pharmacist Ilisa Bernstein explains how expiration dates help determine if medicine is safe to ...

  7. Radiometric Dating Does Work!

    Science.gov (United States)

    Dalrymple, G. Brent

    2000-01-01

    Discusses the accuracy of dating methods and creationist arguments that radiometric dating does not work. Explains the Manson meteorite impact and the Pierre shale, the ages of meteorites, the K-T tektites, and dating the Mount Vesuvius eruption. (Author/YDS)

  8. A Date with Violence.

    Science.gov (United States)

    Lowe, Robert; And Others

    1997-01-01

    Teen dating violence is common but preventable. A survey of Texas high schoolers showed that half of respondents had been victims of dating violence. A majority of both sexes believed that certain behaviors justified being hit by their dating partners. It is important to raise the awareness of school personnel, parents, and students. Peer…

  9. Carbon 14 dating method

    International Nuclear Information System (INIS)

    This document gives a first introduction to 14C dating as it is put into practice at the radiocarbon dating centre of Claude-Bernard university (Lyon-1 univ., Villeurbanne, France): general considerations and recalls of nuclear physics; the 14C dating method; the initial standard activity; the isotopic fractioning; the measurement of samples activity; the liquid-scintillation counters; the calibration and correction of 14C dates; the preparation of samples; the benzene synthesis; the current applications of the method. (J.S.)

  10. Dating and Sexual Feelings

    Science.gov (United States)

    ... take a quiz to find out if your relationship is one to love or leave. What teens are saying about sex Talking to your partner about sex It’s not too late to stop having sex Could I be gay? Dating older guys Staying safe when dating What ...

  11. Radiometric Dating in Geology.

    Science.gov (United States)

    Pankhurst, R. J.

    1980-01-01

    Described are several aspects and methods of quantitatively measuring geologic time using a constant-rate natural process of radioactive decay. Topics include half lives and decay constants, radiogenic growth, potassium-argon dating, rubidium-strontium dating, and the role of geochronology in support of geological exploration. (DS)

  12. Second Quaternary dating workshop

    International Nuclear Information System (INIS)

    The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies emphasizing on the methodologies used and sample preparation

  13. Advance in thermoluminescence dating

    International Nuclear Information System (INIS)

    A review on the thermoluminescence dating is presented. It involves seven parts: 1). properties of TL in the phosphorus; 2). centers of luminescence in some crystals; 3). radiation dosimetry; 4). the accumulated dose in different kinds of specimen; 5). preparation of samples for TL determination; 6). calibration of radiation sources in TL dating; 7). equipments of TL determination

  14. Second Quaternary dating workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    The second Quaternary dating methods workshop was held at Lucas Heights and sponsored by ANSTO and AINSE. Topics covered include, isotope and thermoluminescence dating, usage of accelerator and thermal ionisation mass spectrometry in environmental studies emphasizing on the methodologies used and sample preparation

  15. Quaternary dating methods

    International Nuclear Information System (INIS)

    The papers in this book cover absolute, relative and multiple dating methods, and have been written by specialists from a number of different earth sciences disciplines - their common interest being the dating of geological materials within the Quaternary. Papers on absolute dating methods discuss radiocarbon, uranium-series, potassium argon, 40Ar/39Ar, paleomagnetic, obsidian hydration, thermoluminescence, amino acid racemization, tree rings, and lichenometric techniques. Those on relative dating include discussions on various geomorphic relative age indicators such as drainage density changes, hypsometric integrals, bifurcation ratios, stream junction angles, spur morphology, hillslope geometry, and till sheet characteristics. The papers on multiple dating cite examples from the Rocky Mountains, Australia, Lake Agassiz Basin, and the Southern Andes. Also included is the panel discussion which reviews and assesses the information presented, and a field trip guide which discusses the sequences of Wisconian tills and interlayered lacustrine and fluvial sediments. (orig.)

  16. National Geochronological Database

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Radiometric ages of geological materials by K-Ar, Rb-Sr, Sm-Nd, fission track, and U-Th-Pb dating methods. A revision of DDS-14 correcting locations and providing...

  17. Introduction to isotopic geochronology of pre-quaternary age

    International Nuclear Information System (INIS)

    The historical development of Geochronology is summarized, showing its strong relation to Physics. Considerations about radioactivity and its application to radiochronology are made, including the use of U, Th-Pb dating techniques. A vast list of bibliographical references is given for further consultation. (C.L.B.)

  18. Luminescence dating in archaeology

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) dating is routinely applied to burnt lithic material. Simple fires are capable of enabling stones weighing a few hundred grams to reach 450oC, thus zeroing the TL signal. TL dates have been obtained for Upper and Lower Paleolithic sites in Europe and the Near East. TL dating continues to be used for dating pottery and for authentification of ceramic works of art. Some recent studies report the use of optically stimulated luminescence (OSL) (also know as photoluminescence) for dating very small samples of quartz, e.g. from small pieces of pottery or frm metallurgical slag The major recent advance has been in the development of a reliable laboratory procedure for using the OSL signal from quartz to obtain the past radiation exposure. The quartz OSL signal is extremely sensitive to light and is reduced to a negligible level on exposure to direct sunlight for radionuclides during burial, signal to date san.sized quartz grains extracted from sediments, The OSL signal is stimulated by 470 nm light from emitting diodes and the detected using flirters centred on 340 nm A similar signal can be obtained from feldspar grain when are exposed to infrared wavelengths around 880 nm. The infrared stimulated luminescence (IRSL) signals is also rapidly depleted by exposure to sunlight, and dating of colluvial deposits from archaeological sites has been reported

  19. Why date old bones?

    International Nuclear Information System (INIS)

    The methods for pretreatment and purification of bone have not been accorded the same standard protocols that are applied to other sample materials. Many users lack confidence in bone dates, with some justification, and it is not clear how to proceed. With the advent of AMS dating, it is becoming easy to date very small amounts of highly purified samples such as single amino acids from bone collagen. This note serves a warning that there are dangers in the uncritical application of powerful separation and measurement techniques to uncharacterized material. (orig.)

  20. Disinfestation of Date Fruits by Gamma Radiation and Its Effect on the Nutritional Contents of Dates

    International Nuclear Information System (INIS)

    Irradiation dis infestations of Siwa date fruits seems to be a very promising method. Considerations of the health safety of irradiated date fruits involve nutritional contents has been investigated by chemical analysis. The dose of 400 and 1000 Gy were lethal for the different stages of oases date moth, Ephestia calidella. Dates are a good source of iron and potassium, they also contain calcium, magnesium, copper and other minerals. The radiation dose 1000 Gy had mostly affected the carbohydrates content, some minerals as Fe, Ca and Na partially changed by the treatment. Protein and vitamin contents were slightly affected

  1. Radiometric dating methods

    International Nuclear Information System (INIS)

    The general principle of isotope dating methods is based on the presence of radioactive isotopes in the geologic or archaeological object to be dated. The decay with time of these isotopes is used to determine the 'zero' time corresponding to the event to be dated. This paper recalls the general principle of isotope dating methods (bases, analytical methods, validation of results and uncertainties) and presents the methods based on natural radioactivity (Rb-Sr, Sm-Nd, U-Pb, Re-Os, K-Ar (Ar-Ar), U-Th-Ra-210Pb, U-Pa, 14C, 36Cl, 10Be) and the methods based on artificial radioactivity with their applications. Finally, the methods based on irradiation damages (thermoluminescence, fission tracks, electron spin resonance) are briefly evoked. (J.S.)

  2. Methods of dating

    International Nuclear Information System (INIS)

    Scientific methods of dating, born less than thirty years ago, have recently improved tremendously. First the dating principles will be given; then it will be explained how, through natural radioactivity, we can have access to the age of an event or an object; the case of radiocarbon will be especially emphasized. The principle of relative methods such as thermoluminescence or paleomagnetism will also be shortly given. What is the use for dating. The fields of its application are numerous; through these methods, relatively precise ages can be given to the major events which have been keys in the history of universe, life and man; thus, dating is a useful scientific tool in astrophysics, geology, biology, anthropology and archeology. Even if certain ages are still subject to controversies, we can say that these methods have confirmed evolution's continuity, be it on a cosmic, biologic or human scale, where ages are measured in billions, millions or thousands of years respectively

  3. Expiration Dates Matter

    Medline Plus

    Full Text Available ... E-mail | Consumer Updates RSS Feed If your medicine has expired, it may not provide the treatment ... Bernstein explains how expiration dates help determine if medicine is safe to use and will work as ...

  4. Dating and Marriage

    Science.gov (United States)

    ... National HIV/AIDS and Aging Awareness Day National Gay Men's HIV/AIDS Awareness Day National Latino AIDS Awareness Day World AIDS Day Conferences 30 Years of ... Subscribe Translate Text Size Print Dating and Marriage ...

  5. Food Product Dating

    Science.gov (United States)

    ... Standard Forms FSIS United States Department of Agriculture Food Safety and Inspection Service About FSIS District Offices ... Web Content Viewer (JSR 286) Actions ${title} Loading... Food Product Dating "Sell by Feb 14" is a ...

  6. Teen Dating Violence.

    Science.gov (United States)

    O'Keeffe, Nona K.; And Others

    1986-01-01

    Surveyed high school students (N=256) in Sacramento, California. Found that 35.1 percent had experienced some form of abuse in their dating relationships. Explored the severity of the violence and its intergenerational component. (Author/ABB)

  7. NAIP 2014 Image Dates

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — This map is produced by the Aerial Phtography Field Office (APFO) to show the image acquisition dates for the 2014 National Agriculture Imagery Program (NAIP)...

  8. NAIP 2012 Image Dates

    Data.gov (United States)

    Farm Service Agency, Department of Agriculture — This map is produced by the Aerial Phtography Field Office (APFO) to show the image acquisition dates for the 2012 National Agriculture Imagery Program (NAIP)...

  9. Expiration Dates Matter

    Medline Plus

    Full Text Available ... Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers Consumer Updates Expiration Dates Matter ... recalls [ARCHIVED] CDER FOIA Electronic Reading Room Related Consumer Updates How to Dispose of Unused Medicines Identifying ...

  10. A Blind Date

    Institute of Scientific and Technical Information of China (English)

    周立

    2003-01-01

    英语对话:A: Talking about girls, I still remember my first time to meet my girlfriend. Iwas so clumsy and very nervous.B: That’s the same case with me. I had the jitters at my blind date, too.A: Did you also meet your girlfriend at a blind date?B: Yeah. I was actually very shy of speaking to girls, you know?

  11. Principles of radiometric dating

    International Nuclear Information System (INIS)

    One of the major contributions that the study of meteorites has made to our understanding of the origin of the solar system is in defining when that event took place. In addition, several other important events in early solar-system history have been dated using radiochronological techniques applied to meteorites. The principles on which those applications of radiometric dating are based are outlined. 24 references

  12. Online dating and education

    OpenAIRE

    Fritze, Yvonne; Nordkvelle, Yngve Troye

    2012-01-01

    Taking its inspiration from Luhmann’s communication theory, this article looks at online dating from the perspective of teaching and education. While Eros obviously plays an important role in regenerating the desire to communicate, this ardour is often absent from the domain of net-based teaching. The article explores those features of online dating characteristic of distance dialogue, and discusses the extent to which these can be transferred to communication in the teaching context. We furt...

  13. Investigating Age Resolution in Laser Ablation Geochronology

    Science.gov (United States)

    Horstwood, Matt; Kosler, Jan; Jackson, Simon; Pearson, Norman; Sylvester, Paul

    2009-02-01

    Workshop on Data Handling in LA-ICP-MS U-Th-Pb Geochronology; Vancouver, British Columbia, Canada, 12-13 July 2008; Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) uranium-thorium-lead (U-Th-Pb) dating is an increasingly popular approach for determining the age of mineral grains and the timing of geological events. The spatial resolution offered by this technique allows detailed investigations of complex igneous and metamorphic processes, and the speed of data capture allows vast amounts of information to be gathered rapidly. Laser ablation U-Th-Pb dating is therefore becoming an increasingly influential technique to the geochronology community, providing cost-effective and ready access to age data for laboratories and end users worldwide. However, complications in acquiring, processing, and interpreting data can lead to inaccurate age information entering the literature. With the numbers of practitioners expanding rapidly, the need to standardize approaches and resolve difficulties (particularly involving the subjectivity in processing laser ablation U-Th-Pb data) is becoming important.

  14. Radiocarbon Dating the Anthropocene

    Science.gov (United States)

    Chaput, M. A.; Gajewski, K. J.

    2015-12-01

    The Anthropocene has no agreed start date since current suggestions for its beginning range from Pre-Industrial times to the Industrial Revolution, and from the mid-twentieth century to the future. To set the boundary of the Anthropocene in geological time, we must first understand when, how and to what extent humans began altering the Earth system. One aspect of this involves reconstructing the effects of prehistoric human activity on the physical landscape. However, for global reconstructions of land use and land cover change to be more accurately interpreted in the context of human interaction with the landscape, large-scale spatio-temporal demographic changes in prehistoric populations must be known. Estimates of the relative number of prehistoric humans in different regions of the world and at different moments in time are needed. To this end, we analyze a dataset of radiocarbon dates from the Canadian Archaeological Radiocarbon Database (CARD), the Palaeolithic Database of Europe and the AustArch Database of Australia, as well as published dates from South America. This is the first time such a large quantity of dates (approximately 60,000) has been mapped and studied at a global scale. Initial results from the analysis of temporal frequency distributions of calibrated radiocarbon dates, assumed to be proportional to population density, will be discussed. The utility of radiocarbon dates in studies of the Anthropocene will be evaluated and potential links between population density and changes in atmospheric greenhouse gas concentrations, climate, migration patterning and fire frequency coincidence will be considered.

  15. The Realities of Date Rape.

    Science.gov (United States)

    Presley, Cara; Watson, Jennifer; Williams, Audrey R.

    This poster presentation addresses the issue of date rape, specifically in the college environment. Highlighted are date rape statistics, demographics, and date rape drugs. Also discussed are date rape warnings and prevention strategies. It is concluded that college and university administrators must place the issue of date rape and acquaintance…

  16. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

    Chemicals are a part of our daily lives, providing many products and modern conveniences. With more than three decades of experience, The Centers for Disease Control and Prevention (CDC) has been in the forefront of efforts to protect and assess people's exposure to environmental and hazardous chemicals. This report provides information about hazardous chemicals and useful tips on how to protect you and your family from harmful exposure.  Created: 4/10/2007 by CDC National Center for Environmental Health.   Date Released: 4/13/2007.

  17. Expiration Dates Matter

    Medline Plus

    Full Text Available ... En Español Search FDA Submit search Popular Content Home Food Drugs Medical Devices Radiation-Emitting Products Vaccines, ... Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers Consumer Updates Expiration Dates Matter Share ...

  18. Quantum Dating Market

    OpenAIRE

    Arizmendi, C. M.; Zabaleta, O. G.

    2010-01-01

    We consider the dating market decision problem under the quantum mechanics point of view. Quantum states whose associated amplitudes are modified by men strategies are used to represent women. Grover quantum search algorithm is used as a playing strategy. Success is more frequently obtained by playing quantum than playing classic.

  19. Flirting in Online Dating

    DEFF Research Database (Denmark)

    Mortensen, Kristine Køhler

    2015-01-01

    Various fields have examined the activity of flirting, predominantly based on experimental and reported data; the interactional workings are therefore often overlooked. Based on emails and chats from two Danish online dating sites, this article investigates how users negotiate romantic connections...

  20. Thermoluminescence dating of sediments

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) dating of sediments is based on the observation that exposure of quartz and feldspar to sunlight rapidly reduces the TL level to a small residual value. Therefore, sediments transported by air or water will usually be deposited with a very small TL level. When the sediment has been covered as a result of subsequent sedimentation, the TL level again increases with time as a result of exposure of the minerals to the natural background radiation. The TL level is thus a measure of the accumulated radiation dose (the palaeodose), and the time elapsed since sedimentation is given by the ratio of the palaeodose to the annual dose. Techniques for determining the palaeodose are described including the regeneration, additive dose and R-GAMMA methods. Insufficient bleaching during transport, instability of the latent TL signal and non-linear dose response for older samples pose particular problems which are discussed. In several respects, TL dating of sediments is still at the experimental stage, but the method has a great potential for dating sediments within the last 500,000 years, a period for which there are few other absolute dating methods. (author)

  1. Thermoluminescence dating of pottery

    International Nuclear Information System (INIS)

    This report is divided into two parts. The first half describes on the history of thermoluminescence dating, and the latter half, the principle and measurement examples. It was in late 1955 that the measurement of radiation dose using thermoluminescence began. The method to thermoluminescence dating was developed when it was found that most natural stones emit the thermoluminescence. About Greek earthen wares, the study of which was presented in 1961 by G. Kennedy of University of California, the dating was able to be made within the standard deviation of 10%. Since then, this dating method progressed rapidly, and a number of laboratories are now forwarding the investigation. In the samples of natural materials, intensity of thermoluminescence I is proportional to natural radiation dose D which has been absorbed by the samples, i.e. I = kD, where k is the susceptibility of thermoluminescence of the samples. Since k is different in each sample, D can be determined by irradiating the sample with β or γ ray of known dose D0, measuring its luminescence I0, and eliminating k through these two equations, because i0 = kD0. Next, if t is assumed to be the time passed since a pottery was made, D is expressed as Rt, where R is the natural radiation dose per year absorbed by the pottery. Thus t is determined if R is known. The report describes on the method of measuring R. As an example, the results of measurement of the potteries excavated at Iwakura remains, Yorikura, Taishaku-kyo, are listed. Results by 14C dating are also described for reference. (Wakatsuki, Y.)

  2. Dating soil layers by 10Be

    International Nuclear Information System (INIS)

    The main problem in dating soil layers by the cosmogenic nuclide 10Be is the isolation of beryllium from big quantities of sample materials. The authors apply the following chemical process: leaching the sample material with HCl, extraction of Be as acetylacetonate, and ion exchange on diallyl phosphate. It is thus possible to isolate Be(OH)2 in a chemically pure form containing no other radionuclides. This procedure was tested by the determination of 7Be accumulated in soil. The measured 7Be activity corresponds well with the mean activity of 7Be in rain water. Besides humic acids in soils metal hydroxides are able to concentrate Be to a large extent. Thus 10Be was found in iron ore deposits containing limonite. A calculation of the 10Be production rate is given and the possibility of radioactive dating with 10Be using the chemical process mentioned above is discussed. (author)

  3. Plutonium age dating (production date measurement) by inductively coupled plasma mass spectrometry

    OpenAIRE

    Varga, Zsolt; Nicholl, Adrian; Wallenius, Maria; Mayer, Klaus

    2015-01-01

    This paper describes rapid methods for the determination of the production date (age dating) of plutonium (Pu) materials by inductively coupled plasma mass spectrometry (ICP-MS) for nuclear forensic and safeguards purposes. One of the presented methods is a rapid, direct measurement without chemical separation using 235U/239Pu and 236U/240Pu chronometers. The other method comprises a straightforward extraction chromatographic separation, followed by ICP-MS measurement for the 234U/238Pu, 235U...

  4. Truly Blind Dating

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ Compared to parties,bars and nightclubs,in many countries parks are a site for family leisure and recreation and not a spot to find a date.It is not the case in China.Spouse-hunting fairs in big city parks organized by parents eager to see their children tie the knot have made parks in China a haven for relationshiphunters and their parents.

  5. What's the date of

    Institute of Scientific and Technical Information of China (English)

    刘京西

    2009-01-01

    @@ A:What's the date of our final examination? B:I'm not sure.I'll have to look it up.I'll let youknow tomorrow. A:Thank you. A:我们期末考试是哪一天? B:我也说不清.我给你查查,明天告诉你. A:谢谢你.

  6. Radiocarbon dating for contributors

    International Nuclear Information System (INIS)

    This report describes the radiocarbon facility at the Institute of Nuclear Sciences, and is written for potential contributors, current users, and for those who advise others. The report briefly outlines the principles and practices of C-14 dating; with emphasis on factors that enable contributors to judge whether C-14 work is appropriate, and to assist them with the procedures to be followed in order to get the best results. Age determinations, being the main requirements by contributors, have been discussed in detail

  7. Dating Violence among College Students

    Science.gov (United States)

    Iconis, Rosemary

    2013-01-01

    Dating violence is a significant problem on college campuses. More than one-fifth of the undergraduate dating population are physically abused by their dating partners and an even greater percentage are psychologically abused. Researchers have identified risk factors for college student dating violence. Preventive interventions are strongly…

  8. Rendimento e composição química da forragem de sorgo em diferentes épocas de semeadura Yield and chemical composition of forage sorghum at different sowing dates

    Directory of Open Access Journals (Sweden)

    Hélio Peres de Alcântara

    2011-08-01

    Full Text Available Com o objetivo de avaliar o efeito de épocas de semeadura do híbrido de sorgo silageiro Volumax, foi conduzido um experimento no Campus da Universidade Federal de Lavras, em Lavras/MG, em dois anos agrícolas 2006/07 e 2007/08. O delineamento utilizado foi o de blocos ao caso, com cinco tratamentos e três repetições, compreendendo cinco épocas de semeadura (30 de outubro, 15 e 30 de novembro e 15 e 30 de dezembro. Foram avaliados o rendimento de massa verde, seca e proteína bruta além dos teores de P, Ca, K, Mg e S na forragem. Os resultados obtidos permitiram constatar decréscimos no rendimento de forragem com o atraso na época de semeadura. A semeadura de 30 de dezembro proporcionou menores teores de nutrientes na forragem do sorgo.To evaluate the effect of sowing dates of hybrid silage sorghum Volumax, an experiment was conducted on the campus of the Universidade Federal de Lavras, Lavras/MG, in two crop years 2006/07 and 2007/08. The design was to block the case, with five treatments and three replicates with five sowing dates (October 30, November 15 and 30 and December 15 and 30. We evaluated the yield of green mass, dry mass and crude protein and levels of P, Ca, K, Mg and S in forage. The results revealed a decline in forage yield with delayed sowing date. The sowing of December 30 provided lower levels of nutrients in forage sorghum.

  9. Radiocarbon dating: use and abuse

    International Nuclear Information System (INIS)

    Some of the problems associated with radiocarbon dating are discussed with particular reference to the British neolithic site of Briar Hill, Northampton, England. The problems arise when co-ordinating the radiocarbon dates with observed stratigraphy. In particular, three dates are much earlier than expected and no explanation of the early dates can be given as they represent neither sequence nor context. Doubts as to the validity of the dating and, hence, interpretation are expressed. (U.K.)

  10. Laboratory for Radiokrypton Dating

    Science.gov (United States)

    Zappala, J. C.; Jiang, W.; Bailey, K. G.; Lu, Z. T.; Mueller, P.; O'Connor, T. P.

    2015-12-01

    Due to its simple production and transport in the terrestrial environment, 81Kr (half-life = 230,000 yr) is the ideal tracer for old water and ice with mean residence times in the range of 105-106 years, a range beyond the reach of 14C. 81Kr-dating is now available to the earth science community at large thanks to the development of an efficient and selective atom counter based on the Atom Trap Trace Analysis (ATTA) method. ATTA is a laser-based atom counting method where individual neutral atoms of the desired isotope are selectively captured by laser beams, and their fluorescence detected via a CCD camera. ATTA is unique among trace analysis techniques in that it is free of interferences from any other isotopes, isobars, atomic or molecular species. The ATTA instrument at Argonne's Laboratory for Radiokrypton Dating is capable of measuring both 81Kr/Kr and 85Kr/Kr ratios of environmental samples in the range of 10-14-10-10. For 81Kr-dating in the age range of 150 kyr - 1500 kyr, the required sample size is 5 micro-L STP of krypton gas, which can be extracted from approximately 100 kg of water or 40 kg of ice. For 85Kr/Kr analysis, the sample size can be smaller by an order of magnitude. We are continually developing the method towards higher counting efficiency, smaller sample sizes requirements, and higher sample throughput rates. In the past four years, we have performed radiokrypton analysis of over 150 groundwater and ice samples extracted by collaborators from all seven continents. Sample collection and purification was performed by groups including the University of Chicago, the University of Illinois at Chicago, the University of Bern, and the International Atomic Energy Agency. This work is supported by the U.S. DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357.

  11. Bomb pulse radiocarbon dating

    International Nuclear Information System (INIS)

    Modern forensic science has to deal not only with homicides and other traditional crimes but also with more global threats such as the smuggling of nuclear materials, clandestine production of weapons of mass destruction, stockpiling of illicit drugs by state controlled groups and war crimes. Forensic applications have always benefited from the use of advanced analytical tools that can characterize materials found at crime scenes. In this paper we will discuss the use of accelerator mass spectrometry (AMS) as an ultrasensitive tool for the crime laboratories of the third millennium. An important objective in forensic science is to order past events chronologically by analysing materials associated with criminal actions. Radiocarbon dating is known to the general public for its application to historical and prehistorical investigations. Examples of forensic significance include the assassination of the Inca Atahualpa by Francisco Pizarro in the early 1530s, the possible murder of the Tyrolean Ice Man (Oetzi) 5300 years ago and the analysis of the burial cloths allegedly associated with the crucifixion of Jesus Christ . Recent murders, including those associated with war crimes in the Balkans during the 1990s, can be studied using 14C bomb pulse dating. This method has other forensic applications, including investigation of frauds related to food and wine counterfeiting, dating of opium crops and dating of substances used in biological warfare. AMS extends the applicability of the radiocarbon method, allowing the analysis of 14C in submilligram organic samples. Specific molecular compounds extracted from bones, hair, skin and other carbon bearing substances of forensic significance can now be dated, enhancing the sensitivity and reliability of chronological determinations. AMS can also be used to analyse rare actinide isotopes released into the environment during the clandestine production of nuclear weapons or associated with the smuggling of nuclear materials. In

  12. Thermoluminescence of laterites: applicability in dating

    International Nuclear Information System (INIS)

    The northward drift of the Indian subcontinent during the past geological periods brought it under the spell of humid tropical climate in post-mesozoic times which initiated chemical weathering processes (lateritization) of the ancient crustal rocks leading to neomineralization. In the present study, thermoluminescence (TL) of these 'later-formed minerals' has been used to date laterites from a number of localities in India. While the TL emission of most of the laterite samples was poor, three from Kerala, Tamil Nadu and Karnataka states, each derived from mineralogically dissimilar parent rock, yielded measurable TL and provided dates in the range of 2 to 3.6 x 105 yr. It is suggested that TL dating can be a promising tool for such samples, and especially those with low alpha activity (U, Th at sub-ppm levels). (author)

  13. ESR dating of pseudotachylite

    Science.gov (United States)

    Shimada, A.; Toyoda, S.; Takagi, H.; Arita, K.

    2002-12-01

    ESR (electron spin resonance) dating method has been used to determine the ages of quaternary events. When a mineral receives natural radiation, a part of paired electrons in quartz are ionized, and are trapped by lattice defects and impurties as unpaired electrons. The amount of unpaired electrons increases with time. The ESR age is obtained by dividing the total dose of natural radiation by the natural dose rate. Gamma ray doses are given to the sample to obtain the total dose by extrapolating the dose response of the signal intensity to the zero ordinate. The natural dose rate is calculated from U, Th, and K concentrations, and so on. Quartz is one of the promising minerals useful for ESR dating. In the present paper, we attempted to obtain ages of a land slide event. We collected pseudotachylite from Lantan, Himalaya. A land of about 4 km in diameter has found to have slid several kilometers resulting in pseudotachylite at the base. The samples were gently crushed sieved and soaked in 6N HCl for 1 night and then in 20% HF for two hours, but quartz grains were too small to be extracted. However, ESR signals of characteristic quartz were observed. As long as the sample is uniform, it is not crucial to extract pure quartz grains. With the usual procedure of ESR dating, gamma ray irradiation and ESR measurements, we obtained accumulated natural doses of 290 to 450 Gy. The concentrations of radioactive elements, K, U, Th, which give most of the natural dose to quartz grains, were measured by the low background gamma ray spectrometry. We obtained 7.62 ppm of uranium, 21.1 ppm of thorium, and 3.72% of K2O. Assuming the cosmic dose rate of 0.1mGy/y, we obtained 6.08 mGy/y as the natural dose rate. The ESR ages are obtained by dividing the accumulated doses by the natural dose rate to be 49ka from Al center signal (an electronic hole trapped at Al impurity in quartz) and 74ka from Ti center signal (an electron trapped at Ti impurity in quartz) for a sample, and 56ka and

  14. Radiocarbon dates XXI

    International Nuclear Information System (INIS)

    This list includes 105 radiocarbon age determinations on 104 geological samples made by the Radiocarbon Dating Laboratory. They are on samples from various areas as follows: Labrador Shelf (2); Newfoundland (12); Nova Scotia (2); New Brunswick (1); Quebec (3); Ontario (1); Manitoba (1); Alberta (2); British Columbia (15); Yukon Territory (35); Northwest Territories, Mainland (10); Northwest Territories, Arctic Archipelago (21). Details of background and standard for the 2 L and 5 L counters during the period from November 4, 1980 to October 31, 1981 are summarized in Tables 1 and 2; Table 3 gives the number of counts used to determine the average background and standard counting rates; and Table 4 lists the number of different background and standard gas preparations used for counting

  15. Laboratory for Radiokrypton Dating

    Science.gov (United States)

    Lu, Z.; Bailey, K.; Jiang, W.; Müller, P.; O'Connor, T. P.; Zappala, J. C.

    2013-12-01

    Due to its simple production and transport processes in the terrestrial environment, the long-lived noble-gas isotope 81Kr (half-life = 230 kyr) is the ideal tracer for studying old water and ice in the age range of 10^5-10^6 years, a range beyond the reach of 14C. 81Kr dating, a concept pursued in the past four decades by numerous laboratories employing a variety of techniques, is now available for the first time to the earth science community at large. This is made possible by the development of ATTA-3 (Jiang et al., GCA 91, 1-6; 2012), an efficient and selective atom counter based on the Atom Trap Trace Analysis method (Chen et al., Science 286, 1139-1141; 1999). The instrument is capable of measuring both 81Kr/Kr and 85Kr/Kr ratios of environmental samples in the range of 10^-14-10^-10. For 81Kr-dating in the age range of 150 - 1,500 kyr, the required sample size is 5 - 10 micro-L STP of krypton gas, which can be extracted from approximately 100 - 200 kg of water or 40 - 80 kg of ice. For 85Kr/Kr analysis, the required sample size is generally smaller by an order of magnitude because of the isotope's higher initial abundance in the atmosphere. The Laboratory for Radiokrypton Dating is currently equipped to analyze up to 120 samples per year. With future equipment upgrades, this limit can be increased as demand grows. In the period since November 2011, the Laboratory has measured both 81Kr/Kr and 85Kr/Kr ratios in over 50 samples that had been extracted by collaborators from six different continents. The samples were from groundwater wells in the Great Artesian Basin (Australia), Guarani Aquifer (Brazil), and Locust Grove (Maryland); from brine wells of the Waste Isolation Pilot Plant (New Mexico); from geothermal steam vents in Yellowstone National Park; from near-surface ice at Taylor Glacier, Antarctica; and from deep mines in South Africa. Sample collection and purification was performed by groups including the University of Illinois at Chicago, University

  16. Plutonium age dating (production date measurement) by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    This paper describes rapid methods for the determination of the production date (age dating) of plutonium (Pu) materials by inductively coupled plasma mass spectrometry (ICP-MS) for nuclear forensic and safeguards purposes. One of the presented methods is a rapid, direct measurement without chemical separation using 235U/239Pu and 236U/240Pu chronometers. The other method comprises a straightforward extraction chromatographic separation, followed by ICP-MS measurement for the 234U/238Pu, 235U/239Pu, 236U/240Pu and 238U/242Pu chronometers. Age dating results of two plutonium certified reference materials (SRM 946 and 947, currently distributed as NBL CRM 136 and 137) are in good agreement with the archive purification dates. (author)

  17. Dating fired – clay ceramics by rehydroxylation – an evolving method for absolute dating in archaeology

    International Nuclear Information System (INIS)

    Absolute dating is the ultimate tool to help understand the transition of human civilisations from prehistoric to historic times. Ceramics is the most abundant material recovered from archaeological excavations, and therefore its direct dating would be of great value. Dating by rehydroxylation of ceramics potentially is a method that could resolve prominent discrepancies between chronologies derived by science and by the humanities. The method was first suggested in 2009 by British scientists who found that the mass gain of fired clay material by chemically bonded hydroxyl water strictly follows a power law with time (t1/4). So far, a few groups in the world started to investigate this new dating tool, and the method is still in its infancy. In the first part of this talk, a review of the method and its development will be given. The second part will focus on preliminary experiments performed at the VERA laboratory in collaboration with the Atominstitut.(author)

  18. Thermoluminescence dating of historical buildings

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) dating of ceramic materials is nowadays a consolidated and powerful archaeometric technique. The Luminescence Dating Laboratory of the Department of Material Science (Milano Bicocca University) started its activity in this field in 1980 and since then several thousands of samples have been successfully dated. In recent years TL dating has been extensively and systematically applied to bricks sampled from historical buildings spanning from Roman period to the late XVIII century. This particular application of TL dating technique is presented, and its potential and specificity are illustrated and discussed. (author)

  19. Radiation in archaeometry: archaeological dating

    International Nuclear Information System (INIS)

    Crystalline inclusions contained in ceramics act as thermoluminescent dosimeters, the irradiation source being the natural radiation environment. Because of this, various ceramic materials (pottery, bricks, cooked clays, bronze clay-cores) have been dated by thermoluminescence (TL). A short review of the main possibilities of TL dating is given, with some examples that enlighten the advantages and limits of this method in the field of archaeological dating, compared to TL dating of buildings. The assessment of the chronology of Valdivia culture (Ecuador), based on a three-year project of TL dating, is presented and discussed. The overall uncertainty at around 4-5% can be considered the best limit presently available. The uncertainty distribution found among 700 archaeological TL datings and for about 500 building TL datings is also presented. (author)

  20. Dating of Artefacts. Chapter 4

    International Nuclear Information System (INIS)

    categories of such alterations are known: changes in chemical composition, radioactive decay and fission, migration of elements, deformation, depolymerization, ionization, leaching and hydrolysis. Thus, in principle, the modern materials used in recent times to imitate past or ancient objects are not naturally 'aged'. Among the laboratory processes used for art authenticity detection, the science based techniques of absolute dating play a predominant role, as they are considered highly reputable. Indeed, they are efficient in many, but not all, instances, for reasons explained below. This chapter briefly deals with luminescence and radiocarbon techniques, which exploit the above mentioned natural procedures of ionization and decay, respectively, as comprising the most frequently employed approaches in authenticity detection. Both techniques are regarded here as a means of investigating counterfeits.

  1. Duration of formation of magmatic system of polyphase paleozoic alkaline complexes of the Central Kola: U-Pb, Rb-Sr, Ar-Ar data

    International Nuclear Information System (INIS)

    Attempt was made for the determination of duration of all abyssal system formation in the central part of the Kola peninsula. System of isotope methods inclosing Rb-Sr-isochronic dating, 40Ar/39Ar-age analysis of rocks as well as U-Th-Pb-dating is applied. Formation of the Khibiny-Lovozero-Kurga volcano-plutonic system is proposed to have a multiphase character. Summary scheme of the order of events is performed

  2. New zircon data supporting models of short-lived igneous activity at 1.89 Ga in the western Skellefte District, central Fennoscandian Shield

    OpenAIRE

    P. Skyttä; Hermansson, T.; Andersson, J.; M. Whitehouse; P. Weihed

    2011-01-01

    New U-Th-Pb zircon data (SIMS) from three intrusive phases of the Palaeoproterozoic Viterliden intrusion in the western Skellefte District, central Fennoscandian Shield, dates igneous emplacement in a narrow time interval at about 1.89 Ga. A locally occurring quartz-plagioclase porphyritic tonalite, here dated at 1889 ± 3 Ma, is considered the youngest of the intrusive units, based on the new age data and field evidence. This supports an existing interpretation of its fault-controlled emplace...

  3. Radiation in archaeometry: archaeological dating

    International Nuclear Information System (INIS)

    One of the most recurring questions in archaeometry concerns the age of the studied objects. Not all the materials can be dated so far, but the presence of the natural radiation environment has been of great help in finding mechanisms on which many dating techniques are based. The continuous irradiation from the naturally occurring radioisotopes and from cosmic rays causes the filling of electronic trapping levels in non-metallic materials. This kind of materials can, in principles, be dated through the analysis of these filled electronic traps, provided that the manufacturing of the object to be dated coincides with the starting time of filling traps. This condition is satisfied in the case of Thermoluminescence (TL) Dating, that can in principle be applied to all materials whose manufacturing requires a high temperature heating, typically all kinds of clays, but also bricks, burnt flints, porcelains, cooked hearths, bronze clay-cores. The main fields of application of TL Dating are then architectural history, through the analysis of bricks, and Dating in Archaeology which is the subject of this work. A number of examples will be reported to put in evidence usefulness and limits of TL Dating in Archaeology. The statistical precision that can be achieved is limited by the number of different measurements and treatments that are necessary. In some cases the incompleteness of information, typically in relation to environmental radiation and water content in the burial site, can seriously limit TL Dating precision. The sources of errors that affect TL Dating and the meaningful contribution to the archaeological research coming from TL Dating, when correctly and extensively applied, will be discussed relatively to some archaeological excavations and to a few important bronze statues, that have been dated through the analysis of their clay-cores. (author)

  4. Microstructural observation and chemical dating on monazite from the Shilu Group, Hainan Province of South China: Implications for origin and evolution of the Shilu Fe-Co-Cu ore district

    Science.gov (United States)

    Xu, Deru; Kusiak, Monika A.; Wang, Zhilin; Chen, Huayong; Bakun-Czubarow, Nonna; Wu, Chuanjun; Konečný, Patrik; Hollings, Peter

    2015-02-01

    New monazite chemical U-Th-total-Pb (CHIME) ages, combined with microstructural observations, mineral compositions, and whole-rock geochemistry, indicate that the large-scale, banded iron formation (BIF)-type Shilu Fe-Co-Cu ore district in Hainan Province, South China is a multistage product of sedimentation, metamorphism, and hydrothermal-metasomatic alteration associated with multiple orogenies. Two types of monazite, i.e. "polygenetic" and "metamorphic", were identified. The "polygenetic monazite" comprises a magmatic and/or metamorphic core surrounded by a metamorphic rim, and shows complex zoning. Breakdown corona structure, with a core of monazite surrounded by a mantle of fluorapatite, allanite, and/or epidote as concentric growth rings, is commonly observed. This type of monazite yielded three main CHIME-age peaks at ca. 980 Ma, ca. 880 Ma and ca. 450 Ma. The ages which range up to ca. 880 Ma for detrital cores, record a pre-deformational magmatic and/or metamorphic event(s), and is considered to be the depositional time-interval of the Shilu Group and interbedded BIFs in a marine, back-arc foreland basin likely due to the Grenvillian or South China Sibao orogeny. After deposition, the Shilu district was subjected to an orogenic event, which is recorded by the syndeformational metamorphic monazite with ca. 560-450 Ma population. Probably this event not only caused amphibolite facies metamorphism and associated regional foliation S1 but also enriched the original BIFs, and most likely corresponds to the "Pan-African" and/or the South China Caledonian orogeny. The post-deformational "metamorphic" monazite occurs mostly as inclusions in garnet and shows ca. 260 Ma age. It likely represents the Late Permian post-magmatic hydrothermal and related retrograde event(s) initiated by the Indosinian orogeny due to the closure of the Paleo-Tethys. The breakdown of monazite to secondary coronal mineral phases as well as the Fe-remobilization and associated skarnization

  5. Optical stimulated luminescence (OSL) dating

    International Nuclear Information System (INIS)

    Since the pioneering work by Huntley et al. (1985), optical dating is being increasingly recognised as an important technique for establishing a time frame of deposition of sediments (Aitken, 1998). Optical dating differs from thermoluminescence (TL) dating in that visible/infrared light from lasers or LEDs (light-emitting-diodes) is used as a means of stimulation, in contrast to thermal stimulation. It has several advantages over TL dating: (i) the resetting of the OSL (optically stimulated luminescence) clock is more effective than that of TL clock; for sediments transported under water or in other situations where the sediment grains have undergone inhomogeneous bleaching, this property ensures that ages based on optical dating are generally more reliable than TL ages, (ii) the optical dating technique is non-destructive, and multiple readouts of the optical signal is possible; this feature has resulted in the development of single-aliquot and single-grain protocols (Murray and Wintle, 1999; Banerjee et al. 1999), (iii) the sample is not heated as in TL; thus, spurious luminescence is avoided and there is a significant reduction in blackbody radiation. Dating of materials which change phase on heating is also practical, and finally, (iv) thermal quenching of luminescence is negligible, allowing accurate estimation of kinetic parameters using standard techniques and providing access to deep OSL traps. This characteristic may be helpful in extending the limits of optical dating beyond the last 150 ka from a global point of view

  6. The comparison of absolute dating (Radiocarbon dating) and relative dating of Pringapus and Gondosuli temples

    International Nuclear Information System (INIS)

    The absolute dating (radiocarbon, 14C dating) and relative dating of Pringapus and Gondosuli temples in Temanggung regency (district) of Central Java Province have been carried out. The field sampling was done especially with the purpose to obtain vertical data, so that excavation method was adopted in the case. The main data were the ecofacts of organic habitation such as bones, woods, charcoals, shells, and paper artefacts. The artefacts data were used as a comparison. The comparative data analysis were conducted at Yogyakarta archaeological Department Laboratory, thus included dating of artefacts which were performed according to archaeological analysis procedures, generally based on the attributes attached to the artefacts, whereas the absolute dating of charcoal samples were performed in the Radiocarbon Dating Laboratory at Yogyakarta Nuclear Research Centre. Based on the relative dating of epigraphy content on the andesit rock from Gondosuli Temple which showed the year of 754 Saka or 832 AD, the Pringapus Temple was estimated to be built in the 850 AD. According to the absolute dating (Radiocarbon Dating with delta 13C and tree ring corrections) the age for Gondosuli temple based on GDS/LU-2/Spit-7 samples is (384 -602) AD and from GDS/LU-2/Spit-8 = (452 - 652) AD. With these significant differences in the results obtained, it can be concluded that culture environment where the sample were collected already existed before the temple was built. Further investigation is still required

  7. Dating the Quaternary: progress in luminescence dating of sediments

    Science.gov (United States)

    Lian, Olav B.; Roberts, Richard G.

    2006-10-01

    Luminescence dating comprises a collection of numerical-age techniques that are among the most significant chronological tools currently used in Quaternary research. This paper briefly reviews the key historical developments in luminescence dating, from its roots in thermoluminescence dating of heated minerals to the development of optical dating methods for sunlight-exposed sediments. We describe the principles and practicalities of the various techniques commonly used in luminescence dating, including multiple-aliquot, single-aliquot and single-grain procedures, and we discuss some of the latest approaches to recognising and minimising potential errors in age estimation (e.g., by means of component analysis and dose distribution methods in optical dating). The overview also introduces the other papers in this special issue of Quaternary Science Reviews, which address a selection of important issues in basic research, technique development and application of luminescence dating to critical questions in the geological and archaeological sciences, illustrated with examples from around the world and the last million years of Earth history.

  8. Control of insect pests in stored dates using ionizing radiation

    International Nuclear Information System (INIS)

    Arab countries produce more than 73% of the total world production of date palm and dates constitute an important part of the people's diet. They are produced at a certain time of the year and stored to be consumed all year around. Similar to most other agricultural crops, dates are attacked during storage by a number of insect pests causing sever losses. Methyl bromide, a chemical fumigant highly effective in controlling insect pests of stored dates, has been used for over half a century to protect stored food products, including dates, against insect attack. Because of its environmental drawbacks, methyl bromide is being phased out globally with no other chemical to replace it at present. Ionizing radiation, particularly gamma radiation, may offer a good alternative to methyl bromide for protecting food products including stored dates, against insect attack. In this paper, we present details on insect pests of stored dates, their sensitivity to gamma irradiation and the possibility of using gamma irradiation as an alternative to methyl bromide for their control. It also discusses the criteria used for determining the irradiation dose. In addition, it deals with the advantages, legality, practicality and the difficulties that hamper the practical application of this technology. (author)

  9. Date stones in broiler's feeding

    Directory of Open Access Journals (Sweden)

    Gualtieri, M.

    1990-01-01

    Full Text Available To evaluate date stones as dietary component for broilers, two trials were carried out. In the first trial, Tunisian Deglet date stones were used and in the second one, stones were the waste product of an Italian distillery. One-day-old Arbor Acres chickens were cage reared and fed for 6 weeks on 4 experimental diets, which were formulated to be isonitrogenous and isocaloric and differed in cereal component (maize or low tannin sorghum and in inclusion level (0 or 10 % of ground date stones. Birds ' performances were slightly different in the two trials, but overall results indicate that date stones are suitable for use in broiler's feeding under such conditions.

  10. Dating by electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Some natural materials behave like dosimeters in front of the ionizing particle flux coming from environmental radioactivity and the cosmic radiation. This property is used for the dating by Electron Paramagnetic Resonance (EPR). Before presenting the basic principles of the EPR analysis and the dating method which uses such a phenomenous, it is reviewed several types of application currently in course of development. (L.C.)

  11. Microscale radiocarbon dating of paintings

    Energy Technology Data Exchange (ETDEWEB)

    Hendriks, Laura; Hajdas, Irka; McIntyre, Cameron [ETH Zurich, Ion Beam Physics, Zurich (Switzerland); Kueffner, Markus; Ferreira, Ester S.B. [SIK-ISEA, Zurich, Zurich (Switzerland); Scherrer, Nadim C. [Bern University of Applied Sciences, HKB, Bern (Switzerland)

    2016-03-15

    In this paper, radiocarbon dating of paintings using minimal sample sizes has been investigated, in an effort to address the problem of limited access to sample material in paintings. {sup 14}C analyses were conducted on signed and dated paintings from two Swiss artists of the twentieth century. The selected paintings dated from the 1930s and 1960s, provided the opportunity to evaluate the dating accuracy on paintings realized before and after 1950 AD when the {sup 14}C bomb peak was created, as a result of the nuclear tests conducted in the 1950/1960s. The work focused on the one hand on minimizing the size of the canvas sample required for accelerator mass spectrometer radiocarbon measurement on the gas ion source of the MICADAS and, on the other hand, on testing the possibility of dating the organic binder of the paint. Following careful characterization of the paint composition by X-ray fluorescence spectroscopy, Fourier transformed infrared spectroscopy, and Raman spectroscopy, paints containing no other carbon source than the natural organic binder were identified and dated. (orig.)

  12. Re-Os isotopic system and formation age of subcontinental lithosphere mantle

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The determination of the formation age of subcontinental Lithosphere Mantle (SCLM) is a widely concerned issue in mantle geochemistry. It is difficult to obtain the formation age of SCLM using lithophile isotopic systems such as Rb-Sr, Sm-Nd, U-Th-Pb, etc., but as siderophile elements, the Re-Os isotopic system provides a powerful tool for that work. Here a comprehensive review on the recent development in Re-Os dating for SCLM has been given.

  13. Resolving Bias in Laser Ablation Geochronology

    Science.gov (United States)

    Bowring, James; Horstwood, Matthew; Gehrels, George

    2013-06-01

    Increasingly, scientific investigations requiring geochronology utilize laser ablation (LA)-inductively coupled plasma mass spectrometry (ICPMS), taking advantage of the efficiency and throughput possible for uranium-thorium-lead (U-Th-Pb) dating. A number of biases exist when comparing data among laboratories and an ongoing community-based effort is working to resolve and eliminate these biases to improve the accuracy of scientific interpretation based on these data.

  14. The Minerageny of Two Groups of Zircons from Plagioclase- Amphibolite of Mayuan Group in Northern Fujian

    CERN Document Server

    Bao, Xuezhao

    1996-01-01

    Zircon can crystallize in a wide range of physical and chemical conditions. At the same time, it has very high stability and durability. Therefore zircon can grow and survive in a variety of geological processes. In addition, the diffusivity of chemical compositions in its crystal is very low. Consequently, we can trace back the evolution history of the planetary materials containing zircon by zircon U-Th-Pb geochronology and geochemistry studies. However, this depends on our ability to decipher its genesis, namely magmatic or metamorphic origins. In this paper, magmatic and metamorphic zircons were found from plagioclase-amphibolite samples. Their geneses have been determined by zircon morphology, chemical composition zonations and geological field setting combined with their zircon U-Th-Pb ages. We have found obvious differences in micro-scale Raman spectra between these magmatic and metamorphic zircons. The magmatic zircons exhibit a high sloping background in their Raman spectra, but the metamorphic zirco...

  15. Effect of Algerian Varieties Dates on Glycemic, Arterial Blood Pressure and Satiety Responses

    OpenAIRE

    Gourchala Freha, Mihoub Fatma, Derradj Meriem, Henchiri Cherifa

    2016-01-01

    The purpose of our study is to determine the Glycemic Indexes (GIs)of three Algerians varieties of dates in healthy subjects, evaluate the satiety and effect on arterial pressure after their consumption. We have first documented the chemical composition of the dates. 10 healthy subjects consumed the dates (carbohydrates content of 50 g) in order to determine the GIs. The responses of glycaemia were monitored during two hours after the dates taking and compared to the reference glucose. In a r...

  16. Thermoluminescence dating (TL-Dating): an absolute method for archeological dating of ceramic base materials

    International Nuclear Information System (INIS)

    Thermoluminescence dating is one of the known techniques that have been established in many laboratories across the regions. This technique is capable to date the archeological ceramic base materials and provides an absolute measurement with an accuracy of 5%. The study involves the dating of ceramic clay from historical site at Sungai Mas, Kuala Muda, Kedah. Pieces of broken poetry of archeological sample excavated by the Museum Department and Antiquity (JM4) have been dated using the TLD techniques at MINT laboratory. A TLD dosemeter of LiF chips is used for the background and sample dose measurement. The preparation of sample and the calibration techniques for the estimation of palaedose or dose presented in the sample since distant past is established. Results indicate that the samples are in the era of civilization from 200BP to 1600BP. Error factors associated in the measurement procedures are also discussed

  17. Thermoluminescence dating (TL-dating): measurement and accuracy factors in archaeological dating of ceramic base materials

    International Nuclear Information System (INIS)

    Thermoluminescence dating is one of the known techniques that have been established in many laboratories across the region. This technique is capable of dating the archaeological ceramic base materials and provide an absolute measurement with an accuracy of ±15%. The study involves the dating of pottery from a historical site at Sungai Mas, Mukim Kota, Daerah Kuala Muda, Kedah. Pieces of broken pottery of archaeological sample excavated by the Museum Department and Antiquity (JMA) have been dated using the thermoluminescence detector (TLD) techniques at MINT laboratory. A TLD dosemeter of LiF chips is used for the measurement of background and sample dose measurement. The preparation of sample and the calibration techniques for the estimation of palaedose or dose presented in the sample since distant past is established. Results indicate that the samples are in the era of civilization from 200 BP to 1600 BP. Error factors associated in the measurement procedures were identified and discussed. (Author)

  18. Kimberley rock art dating project

    International Nuclear Information System (INIS)

    The art's additional value, unequalled by traditionally recognised artefacts, is its permanent pictorial documentation presenting a 'window' into the otherwise intangible elements of perceptions, vision and mind of pre-historic cultures. Unfortunately it's potential in establishing Kimberley archaeological 'big picture' still remains largely unrecognised. Some of findings of the Kimberley Rock Art Dating Project, using AMS and optical stimulated luminescence (OSL) dating techniques, are outlined. It is estimated that these findings will encourage involvement by a greater diversity of specialist disciplines to tie findings into levels of this art sequence as a primary reference point. The sequence represents a sound basis for selecting specific defined images for targeting detailed studies by a range of dating technique. This effectively removes the undesirable ad hoc sampling of 'apparently old paintings'; a process which must unavoidably remain the case with researchers working on most global bodies of rock art

  19. Thermoluminescence dating of ancient ceramics

    International Nuclear Information System (INIS)

    Absolute dating by the thermoluminescence technique, rather than the relative dating previously aimed for, is possible if allowance is made for radiation attenuation effects. To do this the thermoluminescence measurements are made on crystalline inclusions separated out from the fine-grained clay matrix. These inclusions, which are usually quartz, are large enough for their average radiation dose from alpha particles originating in the clay matrix to be negligible. Since the uranium and thorium are carried predominantly in the clay matrix, the natural thermoluminescence acquired by the inclusions comes effectively only from the beta and gamma contributions. A preliminary test programme on known-age pottery fragments dating back to 8000 B. P. has given correct absolute ages to within ± 20%. (author)

  20. The complexity behind the date

    CERN Multimedia

    2009-01-01

    For the waiting world, and indeed for most of us here at CERN, ‘the LHC schedule’ simply means the date that the LHC will restart - and we only take notice when that end-date changes. But in fact the schedule is a constantly evolving intricate document coordinating all the repairs, consolidation and commissioning in every part of the machine. So, what actually goes on behind the scenes in timing and planning all the work on one of the most complex scientific instruments ever built?

  1. Thermoluminescence dating of stalagmitic calcite

    International Nuclear Information System (INIS)

    The thermoluminescence (TL) method of dating stalagmitic calcite has been applied to twenty-seven samples from two paleolithic cave sites; Pontnewydd, Wales, and Caune de L'Arago, Tautavel, France. Environmental dose-rates were evaluated mainly by means of CaF2 capsule burials. The ages of the stalagmitic samples were independently determined by means of the uranium series disequilibrium method. In general, good agreement is found between the TL and uranium series dates, which cover a range from approximately 15 000 to 300 000 years B.P. It is estimated that the TL method should extend to the order of a million years in good circumstances. (author)

  2. 21 CFR 1312.25 - Expiration date.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Expiration date. 1312.25 Section 1312.25 Food and... SUBSTANCES Exportation of Controlled Substances § 1312.25 Expiration date. An export permit shall not be valid after the date specified therein, which date shall conform to the expiration date specified in...

  3. Nutritional quality evaluation of eighteen date pit varieties.

    Science.gov (United States)

    Habib, Hosam M; Ibrahim, Wissam H

    2009-01-01

    The pits from date palm fruits (Phoenix dactylifera L.) are nutrient dense but the nutrient composition across varieties has not been extensively studied. In the present study, 18 leading varieties of date pits from date fruits cultivated in the United Arab Emirates (Khalas, Barhe, Lulu, Shikat alkahlas, Sokkery, Bomaan, Sagay, Shishi, Maghool, Sultana, Fard, Maktoomi, Naptit Saif, Jabri, Kodary, Dabbas, Raziz and Shabebe) were analyzed and compared for their chemical and physical properties. Dietary fiber, proximate analysis, micronutrients, and physical properties (weight, length, and density) were determined. Significant differences (Pdifferent varieties. The results show that date pits, depending on the variety, contain significant but quite variable amounts of macronutrients and micronutrients, but all varieties are excellent sources of dietary fiber and may therefore serve as important constituents of functional foods. PMID:18925479

  4. Comparative study of radioimmunoassay dates

    International Nuclear Information System (INIS)

    The radioimmunoassay is frequently used in clinical chemistry for the concentration determination of several substances like hormones as thyrotropine and thyroxine. In this experiment the dates of tyroxine radioimmunoassay are processed by three methods: a) like the recommendation of the IAEA, b) Dr. G. Chase method, c) according to the provider. The best method was Dr. Chase's. (author)

  5. Linguistic Dating of Biblical Texts

    DEFF Research Database (Denmark)

    Ehrensvärd, Martin Gustaf

    For two centuries, scholars have pointed to consistent differences in the Hebrew of certain biblical texts and interpreted these differences as reflecting the date of composition of the texts. Until the 1980s, this was quite uncontroversial as the linguistic findings largely confirmed the...

  6. Online Dating and Conjugal Bereavement

    Science.gov (United States)

    Young, Dannagal Goldthwaite; Caplan, Scott E.

    2010-01-01

    This study examined self-presentation in the online dating profiles of 241 widowed and 280 divorced individuals between 18 and 40 years old. A content analysis of open-ended user-generated profiles assessed the presence or absence of various themes, including the user's marital status, the backstory of their lost relationship, and whether they…

  7. Teen-Age Dating Violence.

    Science.gov (United States)

    Kyle, Karla J.

    It has been estimated that one out of three teenage girls will be involved in an abusive relationship or experience violence in their relationships. Given the fact that studies are showing higher incidence of dating violence reported among teenagers, the importance and usefulness of this topic for anyone who works with adolescents cannot be…

  8. Dating volcanic ash by thermoluminescence

    International Nuclear Information System (INIS)

    We demonstrate that accurate thermoluminescence (TL) dates can be obtained on Holocene tephra, both distal and proximal, by utilizing the 2-11 μm glass particles. This glass has the desirable properties of showing no increase in α count-rates on sealing, having no supralinearity correction, exhibiting no anomalous fading, and being relatively sensitive to additive γ doses. (autor)

  9. Recent advances in thermoluminescence dating

    International Nuclear Information System (INIS)

    Initially the application of thermoluminescent dating was to ancient pottery and other baked clay, the detection of forgeries in art ceramics having a particularly powerful impact. In recent years there has been a growing extension of TL into non-pottery materials. Heated flints from paleolithic fire-places is one application. Another is in the dating of igneous rocks from recent volcanic events; formerly this had been impossible on account of the malign phenomenon of non-thermal ('anomalous') fading exhibited by volcanic minerals but this is now being circumvented by utilising TL in the 6000C region of the glow curve. TL dating has also been extended to unburnt calcite, one application being stalagmitic floors in paleolithic caves. Another recent development is the use of TL for dating aeolian sediment and some types of waterborne sediment. These developments give prospect of establishing a TL-based chronology, both for archaeology and quaternary research, extending back well beyond the range of radiocarbon, perhaps reaching a million years ago. (author)

  10. Models dated by 210Pb

    International Nuclear Information System (INIS)

    The 210Pbex present in sediments, regardless of their origin, decays following the law of radioactive decay. If the rate of sediment accumulation and flow of 210Pb are constant and there are no redistribution processes of 210Pbex in the sediment, a profile of 210Pbex should be perfectly exponential. Although some of these conditions are not met in all cases and observed profiles are rarely found perfect exponentials, models dated by 210Pb described in this chapter allow to obtain valid dated. Anyway, the models described should be seen as tools of interpretation and the dates obtained as estimates to be corroborated by alternative observations. It is recommended to the reader to go deeper into the topics discussed in this chapter reading references and bibliography at the end. Throughout, the closed system hypothesis must be met. For dating of sediments implies that the radionuclide used is integrated into the matrix tested unaffected by redistribution processes. No cases of mixed sediments or showing evidence of mobility by diagenesis are addressed in this chapter, although we believe that in some circumstances estimates of the accumulation rates are provided but not of the age of formation. Starting with the first published use of 210Pb as a tool dating ice cores, different authors develop model conditions adapted to the dating of sediments. In this chapter we describe the most widely used models, which are based on assumptions about the flow of 210Pbex the sediment surface, the rate of accumulation and concentration of initial210Pbex in surface sediments. The models describing nomenclatures have been different and even contradictory. To facilitate reading of the chapter we propose a nomenclature based on the fundamental assumptions of each model (not in implementation) and have homogenised the nomenclature used. While the model most commonly used for dating sediments is the CF (Constant Flux - Constant Flow), commonly known as CRS (Constant Rate of Supply), the

  11. What to Expect After Your Due Date

    Science.gov (United States)

    ... Management Education & Events Advocacy For Patients About ACOG What to Expect After Your Due Date Home For ... Your Due Date FAQ069, August 2011 PDF Format What to Expect After Your Due Date Pregnancy What ...

  12. Mold-Ripened Soft Cheeses Fortified with Date Palm Fruit Product as Functional Dairy Products.

    Science.gov (United States)

    Al-Otaibi, Mutlag M; Haddadin, Jamal S; Haddadin, Malik S Y

    2016-01-01

    Date fruit based products are gaining popularity among the consumers in almost all date growing countries due to its added nutritional value. Therefore, novel products were developed by combining two types of foods i.e., soft ripened cheeses and date fruit syrups or date powder. This study is the first to report the surface mold-ripened cheese production with date syrup and date powder. Model cheeses were prepared from pasteurized milk inoculated with Streptococcus thermophilus, Penicillium camemberti and Geotrichum candidum. Date syrup-1, date syrup-2, date powder or the date mixture were added at the stage of curdling. Based on the kinetic growth of the microbial groups in all the treatments, there was no change in the growth of these in various date palm product. On the contrary It may be said that addition of the date fruit product supports their growth. After 35 days, the amounts of total poly phenols were 128.3 ± 1.01, 81.8 ± 1.11, 33.5 ± 2.19, 156.23 ± 1.27 mg GAE/100 g in the cheeses support with date syrup-1, date syrup-2, date powder or the date mixture, respectively. Antioxidant activity of date fruits ranged from 80.13 IC50 (date syrup-2) to 82.23 IC50 (date syrup-1). Based on the chemical characteristics and sensory analysis, the study results showed the potential for innovative application of date products for developing new functional dairy products as an ideal medium for the delivery of biological active compounds with beneficial health effects over. PMID:26930796

  13. TL dating: a novel form of differential dating

    International Nuclear Information System (INIS)

    The basic age equation of thermoluminescence dating contains two types of quantities, namely accumulated dose and dose-rates which, on closer inspection, are dependent on the size of grains used in the dating experiment. This is caused by the attenuation of radiation within the grains and can be made more explicit by introducing functions into the age equation, which quantitatively describe the effect of attenuation. The age then becomes a function of grain size and concentration of radioactive elements. As the specific functions for alpha- beta- and gamma-radiation contribute to very different degrees to the total annual dose, a potential age determination is offered. In a first approximation it is based only on the grain size attenuation of beta-radiation to which the object was exposed. Such kind of dating requires several grain sizes to be investigated, preferably ranging from 100 to 1000 μm in order to make differences in the archaeodose more easily measurable. The linear relation between archaeodose and attenuation factor of beta-radiation permits the evaluation of the age from the gradient and the environmental dose-rate from the intercept of an appropriate plot. The technique has been tested with quartz grains extracted from 700 to 800-years-old bricks. (author)

  14. A method for dating small amounts of uranium

    International Nuclear Information System (INIS)

    In this study we describe a method for uranium dating (i.e. determination of the date of the last chemical purification undergone by the material) by measurement of the 230Th/234U ratio, applicable to sub-microgram quantities. The chosen protocol (AG1x8 resin in hydrochloric acid medium) has been tested on separation microcolumns (100 μl). This 'microchemistry' technique considerably limits the risks of contamination by reagents or the environment. Thorium extraction efficiencies were greater than 90 % and reproducible. The quantities of 230Th introduced by the chemical purification procedure were negligible. Using an ultra-sensitive inductively coupled plasma mass spectrometry measurement technique, detection limits of the order of femtograms (10-15 g) of 230Th were obtained. The complete procedure, chemical separation and isotope measurement, was successfully tested and validated on a few micrograms of uranium. (author)

  15. SHRIMP II analysis of minerals

    International Nuclear Information System (INIS)

    Full text: Ion microprobes are specialised mass spectrometers that allow in situ isotopic and abundance measurements of chemically complex materials with a spatial resolution of 5 to 20 micrometers. The Sensitive High mass Resolution Ion Micro-Probe (SHRIMP II), an Australian built instrument, is designed to achieve high mass resolution (>5000 MRP at the 1% level) and great sensitivity, with detection limits in the ppb range for most elements in the Periodic Table. The SHRIMP ion microprobes have revolutionised geochronology and they are primarily used for U-Th-Pb dating of zircons from geological samples. The in situ analysis capability of the SHRIMP is now recognised as the best method for obtaining highly precise ages for zircons and other accessory minerals in ancient rocks with complex geological histories. The Western Australian SHRIMP II, which is located at Curtin University, provides rapid, precise measurements of isotope ratios in minerals and glasses and has been applied to a wide variety of geological problems and to a few applied physics problems. During the last three years we have expanded the number of minerals that can be used for U-Th-Pb age dating to include titanite, rutile, apatite, badellyite, perovskite and monazite. In addition to age dating the SHRIMP can be used for isotopic tracing. SHRIMP analysis provides the spatial resolution required to study S isotopes in very complex ores from many of Australia's largest ore deposits (Mt Isa, Broken Hill, Olympic Dam). Sulphur isotope ratios can be measured with a precision of 1-2 ppm in both sulphides and sulphates. In situ S isotopic compositions of galena (PbS), sphalerite (ZnS), chalcopyrite (CuS) and pyrite (FeS) has been crucial in the development of models of ore deposition. The in situ analytical capability and the high sensitivity of the SHRIMP II has allowed measurement of, diffusion profiles of REE and other trace element in melt couples, the mineral-melt partition coefficients of these

  16. Composição físico-química e potencial para ensilagem do sorgo-de-guiné gigante em seis épocas de semeadura Physical-chemical composition and ensiling potential of Giant Guinea sorghum in six different sowing dates

    Directory of Open Access Journals (Sweden)

    Gustavo Pavan Mateus

    2005-09-01

    Full Text Available A ausência de culturas alternativas para o cultivo de outono-inverno é um entrave nos sistemas de produção agrícola, principalmente em regiões de inverno seco. O objetivo deste trabalho foi avaliar a produção de forragem, o potencial para ensilagem e a composição química do sorgo-de-guiné gigante (Sorghum bicolor subsp. bicolor raça guinea, de acordo com a época de semeadura. O delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições e seis épocas de semeadura. Verificou-se antecipação dos estádios de desenvolvimento da planta, à medida que houve atraso na semeadura, em virtude de a espécie apresentar sensibilidade ao fotoperíodo. Semeaduras tardias, apesar de menor produtividade, proporcionaram forragem com características químico-bromatológicas melhores. Diante da boa produção de matéria seca e seu potencial para ensilagem, esse genótipo é uma boa opção a ser utilizada.The lack of alternative crops for fall-winter cultivation is a drawback in the utilization of agricultural production systems, especialy in regions with dry winters. The purpose of this study was to evaluate the potential of Giant Guinea sorghum (Sorghum bicolor subsp. bicolor guinea race for forage production, ensiling and plant chemical composition, in different sowing dates. The experimental design was a randomized block, with four replications, and six sowing dates. Although sowing was late, Giant Guinea sorghum showed anticipation in development stages due to sensibility to photoperiod; its dry matter production was low, nevertheless the species presented a better quality of forage mass. Due to the considerable capacity of dry matter production and ensiling potential, this species is a good option.

  17. New application of thermoluminescence: dating

    International Nuclear Information System (INIS)

    The principle is described of applying thermoluminescence in archeological dating of ceramics, building material, glass and porcelain specimens containing a sufficient amount of silicate microcrystals capable of radiation excitation with a sufficient depth of electron traps in which trapped electrons reside at normal ambient temperature (+-40 degC). For measurement, a piece of the specimen (5 to 50 mg) is powdered and its thermoluminescent (TL) curve is measured by an appropriate equipment. The specimen is then irradiated several times with a known dose and the dose absorbed by the specimen during its history is determined from calibration TL curves. The dose rate due to cosmic radiation and natural radioactivity of the specimen and its environment can either be calculated or measured. The absolute age determination error is +-10%, the determinable range of age is 1 to 106 years. As against 14C dating the TL method is less labour demanding and costly. (Ha)

  18. Neutrino, radioactivity and dating wines

    International Nuclear Information System (INIS)

    Wine is a witness of the radioactivity of the atmosphere at the moment of grapes were collected. The possibility of measuring very low radioactivity levels (that was developed for studying neutrinos) has permitted the design of a new non-destructive method of dating bottled wines. This method is based on the detection of the 661 keV photon released whenever an atom of cesium 137 decays. This photon has enough energy to cross the thickness of glass and be detected. The presence of cesium 137 in the atmosphere is mainly due to the military atomic tests performed from 1950 to 1963 and to the Chernobyl accident that took place in 1986, as a consequence this method is valid to date wines that were produced only after 1950. (A.C.)

  19. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2008-01-01

    This series provides the chemical physics field with a forum for critical, authoritative evaluations of advances in every area of the discipline. This stand-alone special topics volume reports recent advances in electron-transfer research with significant, up-to-date chapters by internationally recognized researchers.

  20. Radiocarbon dating of old groundwater - History, potential, limits and future

    International Nuclear Information System (INIS)

    manifold efforts to search for other environmental isotopes applicable for water age determination. 36Cl has been a promising isotope to date fresh water resources with ages between 100 000 and more than 1.5 million years. However, there are several severe problems in the interpretation of 36Cl dates. One is underground production during groundwater aging and the other is the usually high mineralisation and chloride concentration of old groundwater which lower drastically the detection limit. Similar problems obstruct groundwater dating by 129I theoretically within 3 to 90 million years. Isotope hydrologists hope to simplify the detection of 81Kr. This method namely dates also mineralized groundwater with ages between 50 000 up to 1 million years. At present the analytic and detection requirements are, however, still too complicated for its wide use in applied hydrology. The uranium isotope compositions allow dating within the oxygenated zone of fresh groundwater resources as successfully proved for limestone and sandstone aquifers. The situation in the reduction zone is theoretically well evaluated but the complexity of processes as absorption and formation of chemical complex compounds has still prevented any successful application. Theoretically, the continuos formation of 3He and 4He as well as 40Ar in aquifers allows groundwater dating between 10 000 and 10 million years. Diffusion loss, complex exhaustion of such gases from both the earth mantle and crust prevents, however, reliable datings of groundwater. Age determination of old groundwater challenges modelers and isotope hydrologists to find a linkage between the results of finite element modeling and isotope hydrological studies. Even the basic principles are not yet elaborated. On one side a groundwater sample to be dated represents a relatively large compartment of unknown in size of the groundwater resource. On the other side, this compartment contains an unknown number of finite elements of the model

  1. Physicochemical studies for detection of irradiated dry date fruits

    International Nuclear Information System (INIS)

    The kinetic of the water absorption properties of a selected varieties from the Egyptian dry date fruits were carried out. Sakoti, shamia bida, sokaria, candela and malkabee varieties were used to get an idea about their water absorption properties. Malkabee variety was selected for irradiation at different doses of 0.5, 1, 2, 3, 4 and 5 KGy. In order to obtain a fast, reliable and easy techniques for detecting irradiated dates, several physico-chemical and ultrastructural properties were elucidated in this investigation. Regarding to water absorption, the statistical analysis of the water absorption data revealed that, the amount of water absorption (g water/g dry solid) was decreased with increasing the irradiation doses. This phenomena was confirmed when SEM technique was applied, since irradiation caused shrinkage and reduction in the inner cells. The colour indices were measured by colour analyzer (hunter colorimeter). An inversely proportional relationship was observed between the hue angle and the progress in the irradiation dose, In contrast, direct proportional relationship is strongly observed when the color combination a/b was measured. From the chemical analysis point of view, it was observed that irradiation lowered the amount of total sugars by enhanced reducing sugars. From elucidating the physico-chemical properties of the irradiation date palm, it is now possible to establish a stainable fast, reliable and cheap detection method that could be used to distinguish between the irradiated and non-irradiated dry date fruits

  2. 7 CFR 987.12 - Marketable dates.

    Science.gov (United States)

    2010-01-01

    ... RIVERSIDE COUNTY, CALIFORNIA Order Regulating Handling Definitions § 987.12 Marketable dates. Marketable... exeption of Canada. The Committee may establish different requirements for different countries. (d) Product dates. Product dates are marketable dates that are inspected and certified as meeting the...

  3. Thermoluminescence dating of pleistocene sediments

    International Nuclear Information System (INIS)

    After a short introduction on recent trends in quaternary geochronology, this article focuses on the thermoluminescence dating of sediments, whose principles and present limits and prospects are discussed. Results are presented for the TL behaviour of sands from various geological contexts in Brazil. They show that the coarse (approx. 100-200μm) quartz fraction of coastal and intra continental, eolian and fluvial-type deposits, might be datable by TL from the upper Holocene to at least the basis of the upper Pleistocene, with a precision of + - 10-15%. (Author)

  4. Age dating of young groundwater

    International Nuclear Information System (INIS)

    Full text: During the past 40 years, a variety of methods have been developed that can provide information on the age of young groundwater (0-50 year timescale). Groundwater age refers to the time elapsed since recharge, but is model dependent, being based on an interpretation of measured concentrations of environmental tracers in groundwater samples. As a reference point, an 'apparent age', which assumes unmixed samples (piston flow) is often reported, although a number of mathematical models have been developed that can be used to interpret mean age (residence time) of water that discharges from a groundwater reservoir. Other applications incorporate environmental tracer data in the calibration of numerical models of groundwater flow. Environmental tracers that have proven most useful in providing groundwater age information have an atmospheric source and can be grouped according to (1) those based on measurement of the concentrations of both parent and daughter isotopes, such as in applications of 3H/3He in groundwater, (2) those based on the measurement of the activity of a single radionuclide in groundwater, such as in applications of 3H and 85Kr in groundwater dating, and (3) those based on measurement of the concentration of anthropogenic gases in groundwater, such as in applications of chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF6). In the first case, the initial concentration of the radionuclide is reconstructed from the measured concentrations of the parent and daughter isotopes and age is then determined from the decay equation. The second case requires a priori definition of the initial concentration of the radionuclide recharged to the aquifer, and then age is estimated from the measured concentration and the decay equation. In the third case, age information is derived from a prior knowledge of the atmospheric input function of an anthropogenic gas, its solubility in water, and the measured concentration in the water sample. Each method has

  5. Thermoluminescence dating of pleistocene sediments

    International Nuclear Information System (INIS)

    After a short introduction on recent trends in quaternary geochronology, this article focuses on the thermoluminescence (TL) dating of sediments, whose principles, present limits and prospects are discussed. Results are presented for TL behavior of sands from various geological contexts in Brazil. They show that the coarse (approx. 100-200 μm) quartz fraction of coastal and intracontinental, eolian and fluvial - type deposits, might be datable by TL from the upper Holocene to at least the base of the upper Pleistocene, with a precision of +- 10-15%. (Author)

  6. Archaeological dating using physical phenomena

    International Nuclear Information System (INIS)

    A review is given of the science-based techniques that have been used to establish archaeological chronologies from the million-year range down to the historical period. In addition to the discussion of nuclear, atomic and chemical methods indication is given of the way in which the Earth's magnetic field and perturbations of the Earth's orbital motions are useful in this. (author)

  7. Tectonic calibrations in molecular dating

    Institute of Scientific and Technical Information of China (English)

    Ullasa KODANDARAMAIAH

    2011-01-01

    Molecular dating techniques require the use of calibrations, which are usually fossil or geological vicariance-based.Fossil calibrations have been criticised because they result only in minimum age estimates. Based on a historical biogeographic perspective, Ⅰ suggest that vicariance-based calibrations are more dangerous. Almost all analytical methods in historical biogeography are strongly biased towards inferring vicariance, hence vicariance identified through such methods is unreliable. Other studies, especially of groups found on Gondwanan fragments, have simply assumed vicariance. Although it was previously believed that vicariance was the predominant mode of speciation, mounting evidence now indicates that speciation by dispersal is common, dominating vicariance in several groups. Moreover, the possibility of speciation having occurred before the said geological event cannot be precluded. Thus, geological calibrations can under- or overestimate times, whereas fossil calibrations always result in minimum estimates. Another major drawback of vicariant calibrations is the problem of circular reasoning when the resulting estimates are used to infer ages of biogeographic events. Ⅰ argue that fossil-based dating is a superior alternative to vicariance, primarily because the strongest assumption in the latter, that speciation was caused by the said geological process, is more often than not the most tenuous. When authors prefer to use a combination of fossil and vicariant calibrations, one suggestion is to report results both with and without inclusion of the geological constraints. Relying solely on vicariant calibrations should be strictly avoided.

  8. Dating techniques in fault investigations

    International Nuclear Information System (INIS)

    Determining the time of most recent fault movement is an important part of assessing a possible site for a nuclear power plant. The purpose of this paper is not to present research information but to provide a practical guide to some of the dating techniques available to the engineering geologist working on nuclear power plant siting. Emphasis is placed on the practical aspects, such as usable minerals, conditions necessary for them to yield correct dates, degree of accuracy, sample collection, sample size, and sample packaging. In this paper, the usual geologic field techniques are taken for granted (such as those used in stratigraphy, paleontology, and structural analysis) for assessing fault history. Laboratory techniques used in conjunction with or supplemental to field methods are discussed. The specific radiometric methods discussed are 14C(carbon-14), fission track, K-Ar (potassium-argon), thermoluminescense, Rb-Sr (rubidium-strontium), and U-Th (uranium-thorium). Racemization of amino acids, paleomagnetism, and fluid-inclusion techniques are the nonradiometric methods that are discussed. Our experiences with some of these techniques are described as well

  9. A contribution to the study of post-depositional alterations of pottery using TL dating analysis

    OpenAIRE

    Zacharias, N.; Schwedt, A.; Buxeda i Garrigós, Jaume; Michael, C.T.; Mommsen, H.; Kilikoglou, V.

    2007-01-01

    In luminescence dating, the potassium concentration significantly contributes to the dose rate value in the age estimation. Within this study, fine-grain thermoluminescence dating has been applied on sherds of calcareous pottery of known age, excavated at a Roman site in Mallorca, Spain. For those of the samples that showed signs of severe potassium leaching, according to chemical and mineralogical examination, the thermoluminescence analysis provided overestimated dates. By using the known a...

  10. Archaeometric Contribution for Heritage Management Compositional Analysis and dating of ceramics from a Portuguese collection

    OpenAIRE

    Jayshree MUNGUR-MEDHI; Christopher Ian BURBIDGE; Maria Isabel DIAS; Coroado, João

    2010-01-01

    Different analytical methods comprising mineralogical and chemical analysis and thermoluminescence dating were used to assess the most appropriate techniques for the characterisation and dating of a ceramic collection. This study demonstrates the complementary nature of these techniques. The materials studied consist of ceramics from the collection of the Estrada Foundation, which will form part of a future museum in Abrantes Portugal.

  11. A turning-point in the evolution of the Variscan orogen: the ca. 325 Ma regional partial-melting event of the coastal South Armorican domain (South Brittany and Vendee, France)

    International Nuclear Information System (INIS)

    By drastically reducing the bulk strength of crustal materials, partial-melting is one of the main parameter controlling the rheological behaviour of the continental crust. With more than ca. 50% of the outcropping surface characterised by migmatites and granites, the coastal South Armorican domain, offers an opportunity to study deep-orogenic processes and more particularly, to understand the role of partial-melting for the late-evolution of the Variscan belt. To date, time-constraints are scarce hindering the understanding of this crucial stage in the Variscan belt evolution. This paper provides 29 new U-Th/Pb chemical ages on monazite collected over five sampling areas consisting in migmatite domes and late regional classic plutons. Based on structural, textural and chemical criteria, three main U-Th/Pb age-groups are distinguished. The first group, settled at ca. 335-330 Ma concerns samples of restites and core-domains of the monazite crystals for most of the granite massifs. Its significance is ascribed to inherited crystallisation ages probably recording the crossing of prograde monazite forming reactions (i.e. metamorphic iso-grads) during increasing P-T conditions in an overall nappe-stacking context. The second group that clusters at ca. 325-320 Ma corresponds to newly formed monazite grains that crystallised from juvenile silicate melts. Ages of this group are interpreted as crystallisation ages of leucosomes after a major partial-melting event that affected the whole domain. The last ca. 320 Ma group corresponds to rim-domains of monazite crystals. It is interpreted as the emplacement age of most of the large-scale granite massifs and therefore fixes the end of the partial-melting event. The inception and drastic generalisation of partial-melting at peak-P conditions therefore coincides with a major change in the tectonic regime recorded at regional-scale. In the lights of these results, this implies that (1) either continuous stacking of continental

  12. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  13. Dating and analysis of speleosediments from Aridaia at Macedonia, Greece

    Energy Technology Data Exchange (ETDEWEB)

    Zacharias, N. [Institute of Materials Science, N.C.S.R. Demokritos, 15 310 Ag. Paraskevi, Attiki (Greece)], E-mail: zacharias@ims.demokritos.gr; Kabouroglou, E. [Ephorate of Palaeoanthropology and Speleology of Southern Greece, 34B Ardittou Street, 116 36 Athens (Greece); Bassiakos, Y.; Michael, C.T. [Institute of Materials Science, N.C.S.R. Demokritos, 15 310 Ag. Paraskevi, Attiki (Greece)

    2008-02-15

    The study of the cave system A at Aridaia, Greece brought to light sequences of sediment formations including archaeological deposits at their topmost layers, and thin- to fine-quartzed sediment for the rest underneath deposits. Within past studies, radiocarbon and ESR dating provided ages for charcoal samples from the near-surface archaeological units and travertine layers, respectively, recent OSL dating has been focused on the grounds and formation time of mainly the lower most sequences. The study aims at the analysis and chronological estimation of quartz-rich fine sediments using OSL and combined grain size distributions and chemical/mineralogical analysis to provide data about the evolution of the cave environment. The results indicate clastic sedimentation during Late Pleistocene caused by a river flow in the vicinity of the system; neotectonic episodes interrupted this activity which then allowed speleo-chemical processes generating calcitic cave formations.

  14. Dating and analysis of speleosediments from Aridaia at Macedonia, Greece

    International Nuclear Information System (INIS)

    The study of the cave system A at Aridaia, Greece brought to light sequences of sediment formations including archaeological deposits at their topmost layers, and thin- to fine-quartzed sediment for the rest underneath deposits. Within past studies, radiocarbon and ESR dating provided ages for charcoal samples from the near-surface archaeological units and travertine layers, respectively, recent OSL dating has been focused on the grounds and formation time of mainly the lower most sequences. The study aims at the analysis and chronological estimation of quartz-rich fine sediments using OSL and combined grain size distributions and chemical/mineralogical analysis to provide data about the evolution of the cave environment. The results indicate clastic sedimentation during Late Pleistocene caused by a river flow in the vicinity of the system; neotectonic episodes interrupted this activity which then allowed speleo-chemical processes generating calcitic cave formations

  15. Retrospective Birth Dating of Cells

    Energy Technology Data Exchange (ETDEWEB)

    L.Spalding, K; Bhardwaj, R D; Buchholz, B A; Druid, H; Frisen, J

    2005-04-19

    The generation of cells in the human body has been difficult to study and our understanding of cell turnover is limited. Extensive testing of nuclear weapons resulted in a dramatic global increase in the levels of the isotope {sup 14}C in the atmosphere, followed by an exponential decrease after the test ban treaty in 1963. We show that the level of {sup 14}C in genomic DNA closely parallels atmospheric levels, and can be used to establish the time point when the DNA was synthesized and cells were born. We use this strategy to determine the age of cells in the cortex of the adult human brain, and show that whereas non-neuronal cells are exchanged, occipital neurons are as old as the individual, supporting the view that postnatal neurogenesis does not take place in this region. Retrospective birth dating is a generally applicable strategy that can be used to measure cell turnover in man under physiological and pathological conditions.

  16. Blind-date Conversation Joining

    Directory of Open Access Journals (Sweden)

    Luca Cesari

    2013-07-01

    Full Text Available We focus on a form of joining conversations among multiple parties in service-oriented applications where a client may asynchronously join an existing conversation without need to know in advance any information about it. More specifically, we show how the correlation mechanism provided by orchestration languages enables a form of conversation joining that is completely transparent to clients and that we call 'blind-date joining'. We provide an implementation of this strategy by using the standard orchestration language WS-BPEL. We then present its formal semantics by resorting to COWS, a process calculus specifically designed for modelling service-oriented applications. We illustrate our approach by means of a simple, but realistic, case study from the online games domain.

  17. Thermoluminescence dating of Hawaiian basalt

    Science.gov (United States)

    May, Rodd James

    1979-01-01

    The thermoluminescence (TL) properties of plagioclase separates from 11 independently dated alkalic basalts 4,500 years to 3.3 million years old and 17 tholeiitic basalts 16 years to 450,000 years old from the Hawaiian Islands were investigated for the purpose of developing a TL dating method for young volcanic rocks. Ratios of natural to artificial TL intensity, when normalized for natural radiation dose rates, were used to quantify the thermoluminescence response of individual samples for age-determination purposes. The TL ratios for the alkalic basalt plagioclase were found to increase with age at a predictable exponential rate that permits the use of the equation for the best-fit line through a plot of the TL ratios relative to known age as a TL age equation. The equation is applicable to rocks ranging in composition from basaltic andesite to trachyte over the age range from about 2,000 to at least 250,000 years before present (B.P.). The TL ages for samples older than 50,000 years have a calculated precision of less than :t 10 percent and a potential estimated accuracy relative to potassium-argon ages of approximately :t 10 percent. An attempt to develop a similar dating curve for the tholeiitic basalts was not as successful, primarily because the dose rates are on the average lower than those for the alkalic basalts by a factor of 6, resulting in lower TL intensities in the tholeiitic basalts for samples of equivalent age, and also because the age distribution of dated material is inadequate. The basic TL properties of the plagioclase from the two rock types are similar, however, and TL dating of tholeiitic basalts should eventually be feasible over the age range 10,000 to at least 200,000 years B.P. The average composition of the plagioclase separates from the alkalic basalts ranges from oligoclase to andesine; compositional variations within this range have no apparent effect on the TL ratios. The average composition of the plagioclase from the tholeiitic

  18. Teaching the Mathematics of Radioactive Dating.

    Science.gov (United States)

    Shea, James H.

    2001-01-01

    Describes a method used to teach the concept of radiometric dating using mathematical equations. Explores the lack of information in textbooks on how to solve radiometric dating problems using mathematical concepts. (SAH)

  19. What Is Rape and Date Rape?

    Science.gov (United States)

    ... What is rape and date rape? What is rape and date rape? Get help National Sexual Assault Hotline 800-656- ... drinking, it is NOT your fault. What is sexual assault? Sexual assault and abuse is any kind of ...

  20. Thermoluminescence dating: past progress and future trends

    International Nuclear Information System (INIS)

    An account of the historical development of thermoluminescence dating is followed by sections describing: non-thermal fading in volcanic feldspars; feldspars from pottery and burnt stones; stalagmitic calcite - use of image intensifier; sediment dating. (U.K.)

  1. Thermoluminescence dating of various archaeological materials

    International Nuclear Information System (INIS)

    The archaelogical application of thermoluminescence dating is demonstrated by presenting typical cases from the Heidelberg Thermoluminescence Laboratory. The application examples include thermoluminescence dating on various ceramic materials from Neolithic to Medieval periods. (author)

  2. 7 CFR 1773.8 - Audit date.

    Science.gov (United States)

    2010-01-01

    ... (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Audit Requirements § 1773.8 Audit date. (a) The annual... change the as of audit date is obtained, in writing, from RUS. (1) A borrower may request a change in...

  3. Luminescence dating of storm-surge sediment

    OpenAIRE

    Cunningham, A. C.

    2011-01-01

    Geological evidence of storm surges has the potential to provide vital information on storm-surge risk. Sediment from the coastal dunes of the Netherlands contains evidence of extreme floods that occurred before reliable measurements of water level began. For these sediments to be useful in flood-risk analysis, they need to be reliably dated. This thesis investigates the use of Luminescence dating for storm-surge sediment. Luminescence dating is a radiometric dating method, which uses tiny li...

  4. Rethinking benchmark dates in international relations

    OpenAIRE

    Buzan, Barry; Lawson, George

    2014-01-01

    International Relations (IR) has an ‘orthodox set’ of benchmark dates by which much of its research and teaching is organized: 1500, 1648, 1919, 1945 and 1989. This article argues that IR scholars need to question the ways in which these orthodox dates serve as internal and external points of reference, think more critically about how benchmark dates are established, and generate a revised set of benchmark dates that better reflects macro-historical international dynamics. The first part of t...

  5. The unexpected truth about dates and hypoglycemia

    OpenAIRE

    Mohammed I Yasawy

    2016-01-01

    Background: Dates are a concentrated source of essential nutrients, vitamins, minerals, and carbohydrates (CHOs), which are necessary for the maintenance of optimum health. Most of the CHOs in dates come from sugars including glucose and fructose. Dates are commonly consumed in Saudi Arabia, particularly at the time of breaking the fast to provide instant energy and maintain blood sugar level. However, dates may cause hypoglycemia in a rare condition named as heredity fructose intolerance (HF...

  6. Datingguiden - Din guide til bedre online dating

    OpenAIRE

    l'Anglois-Nordgren, Louise Axen; Clausen, Michelle Simone Gram; Nielsen, Helena Louise Lading; Rahbek, Simone Rebekka

    2015-01-01

    The following study will address in which manner it is possible to create an informative communication product, which informs users of online dating about the different aspects of using online dating. The overall purpose of this study is therefore to answer the problem statement listed below: How can we create an informative communication product, which can enlighten users of online dating at the age of 18-34? To answer the problem statement, an informative online dating guide website h...

  7. 38 CFR 21.4135 - Discontinuance dates.

    Science.gov (United States)

    2010-07-01

    ... training: Date of last training. (iv) Farm cooperative training: Date of last class attendance. (v....4135, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed... educational assistance shall be the last date of attendance. (Authority: 38 U.S.C. 3680) (b) Election...

  8. 29 CFR 4281.11 - Valuation dates.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Valuation dates. 4281.11 Section 4281.11 Labor Regulations... Valuation of Plan Benefits and Plan Assets § 4281.11 Valuation dates. (a) Annual valuations of mass-withdrawal-terminated plans. The valuation dates for the annual valuation required under section 4281(b)...

  9. 40 CFR 425.05 - Compliance dates.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Compliance dates. 425.05 Section 425.05 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS LEATHER TANNING AND FINISHING POINT SOURCE CATEGORY General Provisions § 425.05 Compliance dates. The compliance date for new source...

  10. 38 CFR 21.7635 - Discontinuance dates.

    Science.gov (United States)

    2010-07-01

    ...: last date of attendance; and (ii) Independent study: official date of change in status under the... course not leading to a standard college degree, VA will terminate payments effective the last date of...) Change in law or VA issue or interpretation. If there is a change in applicable law or VA issue, or...

  11. 40 CFR 57.106 - Expiration date.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Expiration date. 57.106 Section 57.106 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) PRIMARY NONFERROUS SMELTER ORDERS General § 57.106 Expiration date. Each NSO shall state its expiration date. No...

  12. 21 CFR 211.137 - Expiration dating.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Expiration dating. 211.137 Section 211.137 Food... § 211.137 Expiration dating. (a) To assure that a drug product meets applicable standards of identity, strength, quality, and purity at the time of use, it shall bear an expiration date determined...

  13. Thermoluminescence dating of Brazilian indigenous ceramics.

    Science.gov (United States)

    Farias, T M B; Gennari, R F; Etchevarne, C; Watanabe, S

    2009-08-01

    Two indigenous ceramics fragments, one from Lagoa Queimada (LQ) and another from Barra dos Negros (BN), both sites located on Bahia state (Brazil), were dated by thermoluminescence (TL) method. Each fragment was physically prepared and divided into two fractions, one was used for TL measurement and the other for annual dose determination. The TL fraction was chemically treated, divided in sub samples and irradiated with several doses. The plot extrapolation from TL intensities as function of radiation dose enabled the determination of the accumulated dose (D(ac)), 3.99 Gy and 1.88 Gy for LQ and BN, respectively. The annual dose was obtained through the uranium, thorium and potassium determination by ICP-MS. The annual doses (D(an)) obtained were 2.86 and 2.26 mGy/year. The estimated ages were approximately 1375 and 709 y for BN and LQ ceramics, respectively. The ages agreed with the archaeologists' estimation for the Aratu and Tupi tradition periods, respectively. PMID:19617598

  14. Thermoluminescence dating of Brazilian indigenous ceramics

    International Nuclear Information System (INIS)

    Two indigenous ceramics fragments, one from Lagoa Queimada (LQ) and another from Barra dos Negros (BN), both sites located on Bahia state (Brazil), were dated by thermoluminescence (TL) method. Each fragment was physically prepared and divided into two fractions, one was used for TL measurement and the other for annual dose determination. The TL fraction was chemically treated, divided in sub samples and irradiated with several doses. The plot extrapolation from TL intensities as function of radiation dose enabled the determination of the accumulated dose (Dac), 3.99 Gy and 1.88 Gy for LQ and BN, respectively. The annual dose was obtained through the uranium, thorium and potassium determination by ICP-MS. The annual doses (D an) obtained were 2.86 and 2.26 mGy/year. The estimated ages were ∼1375 and 709 y for BN and LQ ceramics, respectively. The ages agreed with the archaeologists' estimation for the Aratu and Tupi tradition periods, respectively. (authors)

  15. A recent application of thermoluminescence (TL) dating: the glass mosaic tesserae

    International Nuclear Information System (INIS)

    Archaeometry of ancient glass is a field of growing importance, also because absolute dating methods are not available for this material. So far, the presently assessed dating techniques apply only to a particular class of glasses. In the frame of a research project on chemical and physical characterisation of ancient glass, a thermoluminescence (TL) dating feasibility study of a particular class of glasses, the vitreous mosaic tesserae, has been carried out. Preliminary dating results are presented, together with a few considerations about the dependence of the TL sensitivity of such materials on the concentration of the main chromophorous and opacifiers ions. (author)

  16. Dating of fossil hominid: problems and perspectives

    International Nuclear Information System (INIS)

    The hominid dating anterior to the Homo Erectus has been based up to now on the rocks and minerals geochronology of vulcanic origem in stratigraphic relation with the fossils. Two methods are widely used, potassium-argon and uranium fission track dating. The vulcanic material dating; lava, lephra, associated with the hominid leavings show big difficults essentially connected to several types of contamination and modification. Two available examples inside the east-african rift show the probelms linked to these dating. The current progresses in the dating methods can contribute by one hand to a better utilization of the K-Ar and fisson track methods for the vulcanic materials. By other hand, with the introduction of new dating methods (thermoluminescence and electron paramagnetic resonance) will be possible to date directly whether the fossil bone itself or the associated sedimentar material. This open new perspectives in particular for every sites which are not inter-stratified with the vulcanic material. (L.C.)

  17. Example dated with 210Pb

    International Nuclear Information System (INIS)

    In this chapter we describe in detail, using an example, the procedure to date a core with the technique of 210Pb using the models described in Chapter 7. Described below, one by one, the spreadsheets containing the information and calculations necessary to complete a profile geochronology of 210Pb core adapted from Gulf of Tehuantepec, Mexico. In this case, the old model obtained from the CA model could not be validated with 137Cs because the peak age of 137Cs is too old (1985 ± 3 years). Moreover, there was an investment of age between sections 2-3 and 3-4 cm because the activity of the lower section is higher than at the top, most likely due to a change in sediment accumulation. The average value of MAR (obtained with the CFCS model: 0.222 ± 0.016 g cm-2 yr-1) is in good agreement with the range obtained with the model MAR CF (0.03 ± 0.02 to 0.30 ± 0.01 g cm-2 yr-1). The chronology obtained with the CF model is well validated with the peak of 137Cs (section 6-7 cm: 1960-1972). SAR profiles and MAR show a progressive increase from the late nineteenth century, due to economic development and population growth in the Gulf of Tehuantepec. This growth, which has altered the coastal marine circulation and sedimentation regimes, had its greatest impact during the past two decades, after the establishment of three major industrial complexes in the region.

  18. Constraining the Flux of Impactors Postdating Heavy Bombardment Using U-Pb Ages of Impact Glasses

    Science.gov (United States)

    Nemchin, A. A.; Norman, M. L.; Ziegler, R. A.; Grange, M. L.

    2013-01-01

    Spherules of glass varying in size from a few micrometres to a few millimetres are common in the lunar regolith. While some of these glass beads are products of pyroclastic fire fountains others originate as impact melt ejected from the target that breaks into small droplets and solidifies as spherical particles while raining back to the lunar surface. These glasses preserve information about the chemical composition of the target and often contain sufficient amount of radioactive nuclides such as 40K to enable Ar-40-Ar-39 dating of individual beads. Studies measuring the age of glass beads have been used in attempts to establish variations in the flux of impactors hitting the Moon, particularly during the period that postdates the formation of major impact basins [1,2]. These studies proposed a possibility of spike in the impact flux about 800 Ma [2] and over the last 400 Ma [1]. More recently U-Th-Pb isotopic systems have been also utilized to determine the age of impact glasses from the Apollo 17 regolith [3]. Our aim is to extend the application of the U-Pb system in impact glasses to spherules isolated from Apollo 14 soil 14163 in an attempt to further investigate the applicability of this isotopic system to the chronology of impact glass beads and gain additional information on the impact flux in the inner Solar system.

  19. Sampling pottery in luminescence dating studies

    International Nuclear Information System (INIS)

    A programme of dating pottery from Later Prehistoric sites in Britain revealed that pottery sampled from large features such as enclosure ditches is likely to be residual, i.e. not contemporary with the infilling of the feature. This is important since in luminescence dating such features are often preferred due to the simplification of the dosimetry. Dates obtained for the pottery from smaller contexts, however, were clustered and in agreement with the expected date. In the light of these findings, it is recommended that in situations where the purpose of dating the pottery is to date the feature, pottery be sampled from smaller, shorter-lived contexts. This introduces some complications in the dosimetry, but a simple means of determining the gamma dose rate is presented

  20. The Geological Survey of Canada Radiocarbon Dating Laboratory

    International Nuclear Information System (INIS)

    The Radiocarbon Dating Laboratory of the Geological Survey of Canada began routine 14C age determinations in 1961 using a 2 litre copper, proportional counter and CO2 as the counting gas. This counter is operated routinely at a pressure of 2 atmospheres where the maximum dating limit is approximately 40 000 years using the 4σ criterion. In 1964 a 5 litre counter was put into operation. Routinely this counter is operated at a pressure of 1 atmosphere where its dating limit is approximately 40 000 years. When operated at 4 atmospheres its age limit increases to about 54 000 years. Organic samples are burned in a stream of oxygen and the CO2 released is purified on passage through a series of chemicals and traps. Inorganic samples are dissolved in phosphoric acid. Up to the end of 1983 more than 3700 age determinations have been carried out on various types of sample material. Since 1963 twenty-three Geological Survey of Canada Date Lists have been published. The Laboratory also carries out a program of 14C determinations of samples of known age for the purpose of assessing the accuracy of the method and learning more about the natural and man-made 14C distribution and circulation in nature

  1. Petrogenesis and zircon U-Pb dating of skarnified pyroxene-bearing dioritic rocks in Bisheh area, south of Birjand, eastern Iran

    Directory of Open Access Journals (Sweden)

    Malihe Nakhaei

    2014-10-01

    during the melting of the source (Reagan and Gill, 1989. This pattern followed that of calc-alkaline magmas derived from a sub-arc mantle, with scarce or no garnet in the source. Furthermore, Bisheh subvolcanic bodies were enriched in Rb, Ba and Th, indicating that they had experienced interaction with the continental crust (Kuşcu et al., 2002. The chondrite-normalized rare earth element pattern of the studied rocks shows a high ratio of light rare earth elements (LREE to heavy rare earth elements (HREE. All the samples have been plotted in the VAG field. The dioritic rocks from the Bisheh have relatively high Mg# (0.4-0.56, which is consistent with derivation from mantle melts contaminated by continental crust (Rapp and Watson, 1995. The initial 87Sr/86Sr of Bisheh pyroxene diorite porphyry was 0.70606 and the (143Nd/144Ndi isotope compositions and εNd value of these rocks was 0.512424 and -3.05, respectively. These values show that the magma originated from an enriched mantle with crustal contamination. Acknowledgements The authors are grateful to Professor Sun-Lin Chung from the Department of Geosciences, National Taiwan University, for supporting the researchers in the use of U-Th-Pb zircon age dating. References Berberian, M. and King, G.C., 1981. Towards a palaeogeography and tectonics evolution of Iran. Canadian Journal of Earth Science, 18(2: 210–265. Esmaeily, D., Nedelec, A., Valizadeh, M.V., Moore, F. and Cotton, J., 2005. Petrology of the Jurassic Shah-Kuh granite (eastern Iran, with reference to tin mineralization. Journal of Asian Earth Sciences, 25(6: 961-980. Tarkian, M., Lotfi, M. and Baumann, A., 1983. Tectonic, magmatism and the formation of mineral deposits in the central Lut, east Iran. Geological Survey of Iran, geodynamic project (geotraverse in Iran, Tehran, Report 51, 519 pp. Moradi Noghondar, M., Karimpour, M.H., Farmer, G.L. and Stern, C.R., 2011-2012. Sr-Nd isotopic characteristic, U-Pb zircon geochronology, and petrogenesis of Najmabad

  2. Predictors of Male Violence in Dating Relationships

    OpenAIRE

    Jeffrey, Allison Clifford

    1996-01-01

    Dating violence among college students has become a pressing concern. However, to date, the bulk of the research in this area has attempted to discern correlates of marital violence. Little research has been paid to the isolation of predictors of violence that occurs early in the relationship. This paper demonstrates the utility of several risk factors identified among male college students in predicting dating violence. Factors included are history of abuse in the family of origin; inse...

  3. Thermoluminescence dating of Indian archaeological sites

    International Nuclear Information System (INIS)

    In an attempt to provide a chronology for Indian archaeological sites, an extensive pottery dating programme was initiated during 1978-1979. So far we have provided a chronology for seven important Indian archaeological sites. The dated cultures include: 1) the Ochre Colour Ware culture, 2) the Pre-Harappan culture, 3) the megalithic culture and 4) the Painted Grey Ware culture. A complete survey of recently measured TL dates are presented in a model format similar to that used in Radiocarbon. (author)

  4. Composição química, digestibilidade e cinética de degradação ruminal das silagens de híbridos de girassol em diferentes épocas de semeadura Effects of sowing dates on chemical composition, digestibility and ruminal degradation kinetics of silages from sunflower hybrids

    Directory of Open Access Journals (Sweden)

    Renius Mello

    2006-08-01

    hybrids: Rumbosol-91 (forage, M-734 (double purpose, C-11 (double purpose and BRS-191 (grain sowed in October (early, November (normal and December (late. A randomized complete block design in a 4 x 3 factorial arrangement (four hybrids x three seeding dates with three replicates was used. Dry matter values ranged from 23.2 to 43.0%, pH from 4.0 to 5.1, and NH3-N%/TN from 5.3 to 16.8%. Ash values increased from October to December ranging from 6.8 to 8.8%. The Rumbosol-91 showed the lowest content of EE and the highest contents of N in the cell wall, unavailable N and total carbohydrates (TC. Crude protein contents increased from October to December while the opposite was observed for TC. November sowing and the C-11 gave the lowest contents of NDF, NDFcp and ADF. The C-11 sowed in November gave the lowest ADL values. October sowing and the Rumbosol-91 gave the highest content of ADL%/NDF. The Rumbosol-91 gave higher IVDMD and IVNDFD. November sowing and the C-11 and M-734 hybrids gave the highest value of TDN. Only one degradation profile was necessary to fit DM disappearance data. The proportion of undegradable NDF (I increased from October to December sowing, being the BRS-191 sowed in December gave the highest values. The extent (Vf1 and rate (k1 of degradation of soluble fractions of rapid digestion decreased from October to December sowing, being the Rumbosol-91 sowed in October gave the highest values. The overall nutritive value measured by chemical composition, digestibility, total digestible nutrients and ruminal degradation kinetics was better for the M-734 and C-11 hybrids sowed in November.

  5. Research on genetics of rice heading date

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Heading date is one of the most important traits for rice adaptation to cultivation area and crop seasons, and it is mainly determined by photoperiod, basic vegetative growth, and temperature of cultivars. The diversity of combinations of photo-sensitive varieties and the basic vegetative, makes the heading date varied. On one hand, this supplies abundant resources for different ecotypes breeding; on the other hand, it complicates the inheritance of heading date. In recent years, transgression of late maturity has often been encountered, especially between indica and japonica subspecies, this had inhabited the use of hybrid vigor. Therefore, understanding the inheritance basis of heading date is very important for breeding practices.

  6. NERC radiocarbon dating: 1975-1985

    International Nuclear Information System (INIS)

    The paper reviews the work of the Natural Environment Research Council Radiocarbon Dating Laboratory in connection with Quaternary research, over the last decade. A description is given of the development of the dating service and in-house research. Quaternary research investigations aided by radiocarbon dating are described under the topic headings: The late Devensian glacial maximum, late glacial, middle Devensian, palaeomagnetic secular variation in lake sediments, vegetational history, faunal history, palaeolimnology, ground water, volcanology, periglacial research, palaoeohydrology, geomorphology, quaternary events in low-latitudes, environmental archaeology, archaeology, deep sea sediments, continental shelf, coastal geomorphology, and radiocarbon dating in Antarctica. (U.K.)

  7. IMPROVEMENT OF NUTRITIONAL AND HEALTHY VALUES OF YOGHURT BY FORTIFICATION WITH RUTUB DATE

    Directory of Open Access Journals (Sweden)

    Magdy M. Ismail

    2015-04-01

    Full Text Available As is well known, the date fruits are good sources of many nutrients. Also, yoghurt especially bio-yoghurt has a lot of nutritional and healthy benefits. The aim of this study was to combine the benefits of date and bio-yoghurt in one product which can be made by simple manner. Six treatments of yoghurt were made from cow's milk fortified with 10 and 15% rutub date and using classic or ABT-5 cultures. Changes in rheological, chemical, microbial and organoleptic properties of yoghurt were monitored during refrigerated storage (4°C of yoghurt for 15 d. Results showed that fortification with date accelerates the rates of fermentation and lowered coagulation time. For rheological analyses, curd tension, viscosity and water holding capacity values increased whereas curd syneresis values decreased in bio-yoghurt fortified with date. Redox potential values were lower in date yoghurt as compared with control. Acidity, carbohydrate, total solids, dietary fiber and ash contents of yoghurt supplemented with date were higher than those of control. Supplementation of date increased mineral contents (K, Ca, P, Mg, Na and Fe, total nitrogen, water soluble nitrogen, total phenols and total volatile fatty acids of yoghurt. The addition of date improved the viability of lactic acid bacteria and bifidobacteria. The bifidobacteria counts were sufficient to yield numbers of beneficial organisms that were higher than the accepted threshold (106cfu.g-1 for a probiotic effect. Also, date adding improved the body, texture and flavor of the yoghurt.

  8. Using microwaves in Disinsection of dates

    International Nuclear Information System (INIS)

    The date palm plays a very significant role in Tunisia in term of culture as well as social, economic and ecological aspects. The production of the dates which is estimated to 120.000 tons/year ensures the principal income for the majority of the oasis population of the South of Tunisia and constitutes the basis for agricultural, industrial, commercial and tourist activities, offering million of working days. The date palm is cultivated mainly for the production of dates which are consumed locally or also exported abroad but for its by-products (food of the cattle, wind breaks, fuel, construction) which are marketed and/ or used in the everyday life thus taking part in the sedentarisation of the populations and the maintenance of a fragile socio-economic balance. The date moth, Ectomyelois ceratoniae Zell. ( L will epidoptera, Pyralidae) is without question the most significant problem of the Tunisian date palm. The infestation of dates in the field and in the storage and packing houses enormously depreciates the marketable quality of dates and risk to compromise exports in particular those of the variety Deglet Nour. rates of infestations of about 20% are often recorded in Tunisia where as the European standards require rates lower than 5%. In Tunisia the desinsectisation of dates is done until now by the use of methyl bromide, its high toxicity substantially reduces the duration of date treatment, and consequently the treated volumes. The replacement of this product becomes an urgent need its use will not be authorized by 2015. Within the framework of a agreement between the Regional Research Center in Oasis Agriculture (CRRAO), The Interprofessional Grouping of Fruits (GIF), and the Italian Company IMETEC, the use one of micro-waves as a desinsectisation method of dates was evaluated. The results of this present work showed that total desinsectisation of dates by microwaves can be obtained only with homogeneous dates in term of water content. Total

  9. 16 CFR 1201.7 - Effective date.

    Science.gov (United States)

    2010-01-01

    ... architectural glazing material is permanently labeled to indicate it conforms to ANSI Z97.1-1972 or 1975 or is... STANDARD FOR ARCHITECTURAL GLAZING MATERIALS The Standard § 1201.7 Effective date. The effective date of... be January 6, 1980. (b) Architectural glazing materials manufactured before July 6, 1977 may...

  10. Peer Involvement in Adolescent Dating Violence

    Science.gov (United States)

    Stephenson, Pam S.; Martsolf, Donna; Draucker, Claire Burke

    2013-01-01

    This study investigated the ways in which peers are involved in adolescent dating violence. Eighty-eight young adults aged 18-21 were interviewed and asked to reflect on aggressive dating relationships they experienced as teens. The researchers used grounded theory to analyze the data. Findings showed that male and female peers were involved in…

  11. 40 CFR 211.202 - Effective date.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Effective date. 211.202 Section 211.202 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS PRODUCT NOISE LABELING Hearing Protective Devices § 211.202 Effective date. Manufacturers of...

  12. 38 CFR 3.54 - Marriage dates.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Marriage dates. 3.54..., Compensation, and Dependency and Indemnity Compensation Relationship § 3.54 Marriage dates. A surviving spouse may qualify for pension, compensation, or dependency and indemnity compensation if the marriage to...

  13. 16 CFR 1306.5 - Effective date.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Effective date. 1306.5 Section 1306.5 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS BAN OF... lawn darts in the chain of distribution on or after that date....

  14. Accelerator mass spectrometry dating at Catalhoeyuek

    International Nuclear Information System (INIS)

    Several charred plant and charcoal samples from various stratigraphic levels of the Neolithic Site, Catalhoeyuek - Turkey, were dated in the AMS facility of Purdue University (PRIME Lab). Radiocarbon dates reveal a complicated chronology, as was foreseen from archeological investigations. Our measurements suggest that this unique Neolithic town may have been initiated at the East mound around 8390 BP. (orig.)

  15. Teen Dating Violence Prevention Program Assessment

    Science.gov (United States)

    Lucas, Quincy Arrianna Rose

    2013-01-01

    The American Psychological Association (APA) has identified the prevention of and intervention in relationship violence as a top priority (APA, n.d.). According to the Center for Disease Control and Prevention's 2012 Teen Dating Violence Fact Sheet, dating violence is a serious problem in the United States. In accordance with Foshee et al. (1998):…

  16. The Galileo arrival date selection process

    Science.gov (United States)

    Ludwinski, Jan M.; Gershman, Robert

    1988-01-01

    The Galileo arrival date selection process has culminated in the selection of December 7,1995. This arrival date will provide excellent science opportunities at Jupiter as well as the first spacecraft reconnaissance ever of not one, but two asteroids during the cruise to Jupiter.

  17. 7 CFR 953.120 - Nomination date.

    Science.gov (United States)

    2010-01-01

    ... § 953.120 Nomination date. The names of committee nominees shall be supplied to the Secretary in such... 7 Agriculture 8 2010-01-01 2010-01-01 false Nomination date. 953.120 Section 953.120 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing...

  18. 40 CFR 141.152 - Effective dates.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Effective dates. 141.152 Section 141.152 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Consumer Confidence Reports § 141.152 Effective dates. (a)...

  19. 28 CFR 57.4 - Expiration date.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Expiration date. 57.4 Section 57.4 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) INVESTIGATION OF DISCRIMINATION IN THE SUPPLY OF PETROLEUM TO THE ARMED FORCES § 57.4 Expiration date. This part shall remain in effect until...

  20. Radiocarbon dating prehistoric pottery from Northern Europe

    DEFF Research Database (Denmark)

    Philippsen, Bente; Craig, Oliver; Heron, Carl;

    2012-01-01

    -depositional contamination with organic carbon, such as humic acids, may also be problematic. We present these data with radiocarbon datings of contemporaneous terrestrial and aquatic samples to find out the true age of the pottery and estimate the reservoir age. Lipid analysis and bulk carbon and nitrogen stable isotope......Direct dating of the pottery is an important goal in archaeological research and many attempts have been made using radiocarbon. One important goal has been to date the earliest pottery in a region to assess the origin and dispersal of ceramic technology. Also with the increasing application of...... organic residue analysis to study pottery use, it has become important to combine residue data with direct dates on the artefact being investigated. In this study we have radiocarbon dated different organic materials associated with archaeological potsherds from three Ertebølle sites in Northern Germany...

  1. Chemical use

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of research and activities related to chemical use on Neal Smith National Wildlife Refuge between 1992 and 2009. The chemicals used on the Refuge...

  2. Automation of TL brick dating by ADAM-1

    International Nuclear Information System (INIS)

    Thermoluminescence has become an established dating method for ceramics and more recently for bricks. Based on the experiences of the work carried out since the late 1970's at the Rathgen-Forschungslabor in Berlin on the dating of bricks from historic architecture, and after evaluating all commercially available and some individually built automated and semi-automated TL-readers, a specially adapted machine for the fine grain dating of bricks was constructed in an interdisciplinary research project, undertaken by a team recruited from three faculties of the Czech Technical University in Prague. The result is the automated TL-reader ADAM-1 (Automated Dating Apparatus for Monuments) for the dating of historic architecture. Both the specific adaptation of the technique and the necessary optimal automation have influenced the design of this TL-reader. The principle advantage of brick as opposed to ceramic TL-dating emerges from the possibility of being able to obtain both a large number of samples and an above average quantity of datable material from each sample. This, together with the specific physical and chemical conditions in a brick wall, allowed a rethinking of the traditional error calculation and thus lower error margins as those obtained when dating ceramic shards. The TL-reader must therefore be able to measure and evaluate automatically numerous samples. The annular sample holder of ADAM-1 has 60 sample positions, which allow the irradiation and evaluation of samples taken from two locations. The thirty samples from one sampling point are divided into subgroups, which are processed in various ways. Three samples serve for a rough estimate of the TL sensitivity of the brick material. Nine samples are used for the measurement of 'natural TL' of the material. A further nine samples are used for testing the sensitivity of the material to beta radiation. The last nine samples serve for the testing of the sensitivity to alpha radiation. To determine the

  3. Parsing and Matching Dates in VIAF

    Directory of Open Access Journals (Sweden)

    Jenny A. Toves

    2014-10-01

    Full Text Available The Virtual International Authority File (OCLC Online Computer Library Center 2013 http://viaf.org is built from dozens of authority files with tens of millions of names in more than 150 million authority and bibliographic records expressed in multiple languages, scripts and formats. One of the main tasks in VIAF is to bring together personal names which may have various dates associated with them, such as birth, death or when they were active. These dates can be quite complicated with ranges, approximations, BCE dates, different scripts, and even different calendars. Analysis of the nearly 400,000 unique date strings in VIAF led us to a parsing technique that relies on only a few basic patterns for them. Our goal is to correctly interpret at least 99% of all the dates we find in each of VIAF’s authority files and to use the dates to facilitate matches between authority records. Python source code for the process described here is available at https://github.com/OCLC-Developer-Network/viaf-dates.

  4. Date Violence and Date Rape among Adolescents: Associations with Disordered Eating Behaviors and Psychological Health.

    Science.gov (United States)

    Ackard, Diann M.; Neumark-Sztainer, Dianne

    2002-01-01

    A study assessed prevalence of date violence and rape in 81,247 adolescents. Approximately 9% of girls and 6% of boys had experienced date violence or rape. Date violence and rape was associated with higher rates of disordered eating behaviors and suicidal thoughts and attempts, and lower emotional well-being and self-esteem. (Contains…

  5. A Phenomenological Investigation of Adolescent Dating Relationships and Dating Violence Counseling Interventions

    Science.gov (United States)

    Hays, Danica G.; Michel, Rebecca E.; Cole, Rebekah F.; Emelianchik, Kelly; Forman, Julia; Lorelle, Sonya; McBride, Rebecca; Sikes, April

    2011-01-01

    Despite the prevalence of dating violence, incidences often go unreported due to a lack of awareness among students as to appropriate dating behaviors. This phenomenology investigated how adolescents conceptualize and experience dating relationships. We explored adolescent females' definitions of healthy and abusive relationships, experiences with…

  6. Chemical sensor

    Science.gov (United States)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  7. Development of thermoluminescence dating techniques at Oxford

    International Nuclear Information System (INIS)

    The two-decade long history of thermoluminescene as a pottery dating method is surveyed with particular reference to the various problems that have been encountered in the Oxford Laboratory's research programme. Effects, such as supralinearity and radon emanation, are explained in terms of how they are measured and how their existence influences thermoluminescence (TL) dating accuracy (currently close to plus minus 7% per analysis). Illustrations of Thermoluminescence (TL) applications include a Nok culture terracotta from Nigeria and a Cambodia bronze Buddha figure of the Khmer period, dated ising the ceramic-like casting-core retained within it. (author)

  8. ESR dating of tooth enamel samples

    International Nuclear Information System (INIS)

    Five tooth samples from the palaeoanthropological site of Jinniushan were dated with both electron-spin-resonance (ESR) and uranium-series techniques. The ESR age of about 230 ka is in good agreement with the U-series dating result, which confirms the hypothesis of possible coexistence of Homo erect us and Homo sapiens in China. Problems in ESR dating are discussed such as: 1) inappropriate of simple exponential extrapolation for accumulated dose determination; 2)experimental measurement of alpha detection efficiency and radon emanation and 3)selection of U-uptake model

  9. Zircon dating of oceanic crustal accretion.

    Science.gov (United States)

    Lissenberg, C Johan; Rioux, Matthew; Shimizu, Nobumichi; Bowring, Samuel A; Mével, Catherine

    2009-02-20

    Most of Earth's present-day crust formed at mid-ocean ridges. High-precision uranium-lead dating of zircons in gabbros from the Vema Fracture Zone on the Mid-Atlantic Ridge reveals that the crust there grew in a highly regular pattern characterized by shallow melt delivery. Combined with results from previous dating studies, this finding suggests that two distinct modes of crustal accretion occur along slow-spreading ridges. Individual samples record a zircon date range of 90,000 to 235,000 years, which is interpreted to reflect the time scale of zircon crystallization in oceanic plutonic rocks. PMID:19179492

  10. TL and EPR dating: some applications

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S. [Institute of Physics, University of Sao Paulo, Sao Paulo (Brazil)

    2006-07-01

    The intensity of thermoluminescence light emitted by a crystal is a function of radiation dose. The number of defects or of radicals in a crystal or organic substances is also a function of radiation dose. Since such defects or radicals present EPR signals, the EPR intensity is also a function of radiation dose. These facts are basis for radiation dosimetry and can be applied in dating of archaeological potteries or other materials, as well as in dating geological substances such as sediments, caves speleothemes, animal teeth and bones. Recent investigation on sensitized quartz based dosimeters and dating calcite covering ancient wall painting to find early settlers in Brazil will be presented. (Author)

  11. TL and EPR dating: some applications

    International Nuclear Information System (INIS)

    The intensity of thermoluminescence light emitted by a crystal is a function of radiation dose. The number of defects or of radicals in a crystal or organic substances is also a function of radiation dose. Since such defects or radicals present EPR signals, the EPR intensity is also a function of radiation dose. These facts are basis for radiation dosimetry and can be applied in dating of archaeological potteries or other materials, as well as in dating geological substances such as sediments, caves speleothemes, animal teeth and bones. Recent investigation on sensitized quartz based dosimeters and dating calcite covering ancient wall painting to find early settlers in Brazil will be presented. (Author)

  12. Thermoluminescence dating of Australian palaeo-earthquakes

    Science.gov (United States)

    Hutton, J.T.; Prescott, J.R.; Bowman, J.R.; Dunham, M.N.E.; Crone, A.J.; Machette, M.N.; Twidale, C.R.

    1994-01-01

    Thermoluminescence (TL) dating is a useful tool for determining the age of prehistoric earthquakes by dating deposits that are stratigraphically related to fault scarps that formed during the earthquakes. TL dating of aeolian sand in the area of the 1988 Tennant Creek, Northern Territory, earthquakes provides evidence that similar earthquakes have not ruptured the causative faults for at least 50 ka. Pilot TL measurements of deposits associated with the Roopena and Ash Ridge fault scarps near Whyalla on Eyre Peninsula, South Australia, suggest an age of 140 ka for the Quaternary deposits associated with the formation of the scarps. ?? 1994.

  13. Annual radiation dose in thermoluminescence dating

    International Nuclear Information System (INIS)

    The annual radiation dose in thermoluminescence dating has been discussed. The autor gives an entirely new concept of the enviromental radiation in the thermoluminescence dating. Methods of annual dose detemination used by author are dating. Methods of annual dose determination used by author are summed up, and the results of different methods are compared. The emanium escapiug of three radioactive decay serieses in nature has been considered, and several determination methods are described. The contribution of cosmic rays for the annual radiation dose has been mentioned

  14. Thermoluminescence dating in archaeology and quaternary geology

    International Nuclear Information System (INIS)

    In the last four years progress in TL dating has been in three main directions. Extensive studies of both quartz and alkali feldspar inclusions extracted from the same pottery samples now enable us to obtain a TL age with a total uncertainty of less than 7%. A major obstacle, which until now has prevented the direct dating of lava flows, has been overcome by measuring very high temperature TL of plagioclase feldspars. Perhaps the most exciting development has been the application of TL dating to sedimentary deposits such as loess and deep-sea cores which have had their geological TL removed by sunlight during weathering. (author)

  15. ESR dating of pottery: a trial

    International Nuclear Information System (INIS)

    An attempt of electron spin resonance (ESR) dating of pottery is described using natural radiation defects in quartz grains. Fragments of a neolithic ''Trichterbecher'', previously dated by thermoluminescence (TL), were used. Although various radiation induced centres were identified, only the aluminium centre was useful for dating. The annual dose rate was calculated for a grain distribution from 0.1 to 1 mm, using external as well as internal components. The TL and ESR ages of (4720 ± 300)a and (4976 ± 800)a [(4589 ± 900)a], respectively, are in agreement; however, the uncertainty range in case of the ESR experiment is much larger. (Author)

  16. Thermoluminescence dating of late-glacial sand sediments

    International Nuclear Information System (INIS)

    Ten Late-Glacial sediments were dated by the regeneration method combined with the plateau criteria. The thermoluminescence (TL) dates were compared with independent dates assessed indirectly by radiocarbon dating or varve chronology. For comparison, the 14C dates were calibrated by adding 1000 yr to the conventional results. Eight TL dates agreed with the 14C dates within the uncertainty of the TL dates (± 1 ka), one was overestimated and one underestimated. (author)

  17. Perfect zircon for rock dating no fairy tale

    International Nuclear Information System (INIS)

    The scheme used to date rocks is based on the radioactive decay of uranium. Minute traces of uranium locked inside the zircon crystals have been decaying over aeons, producing lead. Scientists know that the decay occurs at a fixed rate and how quickly it happens. By measuring the relative amounts of uranium and lead encased in the crystals, scientists can determine how old the rock is. But sometimes lead is lost from zircon crystals via processes such as weathering (if the rocks were exposed on the surface) or deformation and metamorphism (if the rocks had crystallised deep in the earth and been subjected to high temperatures and pressure). Hence the special nature of the Temora rocks- a 417 million years old zirconium-containing rock which have been partially exposed in recent times in a remote paddock in NSW, Australia. SHRIMP dating was used for initial tests on the Temora rocks. Then, in December last year, the sample was sent to the world-recognised authority, Canada's Royal Ontario Museum, for independent analysis and dating via chemical decomposition. The museum confirmed the near perfect quality of the zircon and its age

  18. The interpretation of archaeological dates from an AMS perspective

    International Nuclear Information System (INIS)

    The XVII century saw the establishment of the scientific method and scholars such as Galileo were giving excellent contributions to a variety of fields ranging from the natural sciences to the humanities. At the dawn of the new millenium, after a period of excessive specialization, the scientific climate is once again encouraging broad collaborations across different disciplines. For projects involving AMS measurements in general and radiocarbon dating in particular, the benefits of this new trend are numerous. For example, the full potential of the radiocarbon dating method can be exploited only through the mutual understanding of the problems related to sample selection, chemical preparation, AMS measurement, data analysis and interpretation. This paper is intended to enhance the exchange of information by reporting to our current and potential collaborators about the latest technical developments undertaken at the ANTARES AMS facility at ANSTO. Furthermore, we will present two splendid examples of collaborative research: the radiocarbon dating of a replica of a famous chesspiece and the archaeological investigations at the ancient settlement of Sos Hoyuk (north-eastern Anatolia, Turkey) where the multidisciplinary approach was the key to a better understanding of the social structure, settlement patterns, land use and cultural contact, especially with the lands of Trans-Caucasus. (author). 12 refs., 4 figs

  19. Chemical machining

    Directory of Open Access Journals (Sweden)

    A. Yardimeden

    2007-08-01

    Full Text Available Purpose: Nontraditional machining processes are widely used to manufacture geometrically complex and precision parts for aerospace, electronics and automotive industries. There are different geometrically designed parts, such as deep internal cavities, miniaturized microelectronics and fine quality components may only be produced by nontraditional machining processes. This paper is aiming to give details of chemical machining process, industrial applications, applied chemical etchants and machined materials. Advantages and disadvantages of the chemical machining are mentioned.Design/methodology/approach: In this study, chemical machining process was described its importance as nontraditional machining process. The steps of process were discussed in detail. The tolerances of machined parts were examined.Findings: Paper describes the chemical machining process, industrial applications, applied chemical etchants and machined materials.Practical implications: The machining operation should be carried out carefully to produce a desired geometry. Environmental laws have important effects when chemical machining is used.Originality/value: The importance of nontraditional machining processes is very high.

  20. Chemical Leukoderma.

    Science.gov (United States)

    Bonamonte, Domenico; Vestita, Michelangelo; Romita, Paolo; Filoni, Angela; Foti, Caterina; Angelini, Gianni

    2016-01-01

    Chemical leukoderma, often clinically mimicking idiopathic vitiligo and other congenital and acquired hypopigmentation, is an acquired form of cutaneous pigment loss caused by exposure to a variety of chemicals that act through selective melanocytotoxicity. Most of these chemicals are phenols and aromatic or aliphatic catechols derivatives. These chemicals, however, are harmful for melanocytes in individuals with an individual susceptibility. Nowadays, chemical leukoderma is fairly common, caused by common domestic products. The presence of numerous acquired confetti- or pea-sized macules is clinically characteristic of chemical leukoderma, albeit not diagnostic. Other relevant diagnostic elements are a history of repeated exposure to a known or suspected depigmenting agent at the sites of onset and a macules distribution corresponding to sites of chemical exposure. Spontaneous repigmentation has been reported when the causative agent is avoided; the repigmentation process is perifollicular and gradual, taking place for a variable period of weeks to months. PMID:27172302

  1. Climate signatures of grape harvest dates

    Directory of Open Access Journals (Sweden)

    M. Krieger

    2010-08-01

    Full Text Available Grape harvest dates have been recorded in many European locations for several centuries, and potentially contain important information about past climate. In this study, we systematically analyse the relationship of grape harvest dates recorded in the Burgundy region (France with different climate data sets in order to understand the connection between climatic conditions and the time of harvest. The results point to a primary dependence of the grape harvest on the temperature from April to August. The strength of this connection depends on the winter to summer temperature relationship and increases over the last 100 years. The grape harvest date is also related to the winter temperature. This connection is non-stationary on interannual, but stable on decadal-to-multidecadal time scales. Therefore, the grape harvest date can be used for independent reconstructions of local April-to-August temperature on interannual time scales as well as remote winter temperature on decadal-to-multidecadal time scales.

  2. Coconut, date and oil palm genomics

    Science.gov (United States)

    A review of genomics research is presented for the three most economically important palm crops, coconut (Cocos nucifera), date palm (Phoenix dactylifera) and oil palm (Elaeis guineensis), encompassing molecular markers studies of genetic diversity, genetic mapping, quantitative trait loci discovery...

  3. Color features for dating historical color images

    OpenAIRE

    Fernando, Basura; Muselet, Damien; Khan, Rahat; Tuytelaars, Tinne

    2014-01-01

    Fernando B., Muselet D., Khan R., Tuytelaars T., ''Color features for dating historical color image'', IEEE international conference on image processing - ICIP 2014, 5 pp., October 27-30, 2014, Paris, France.

  4. Kommunikation på online dating

    OpenAIRE

    Steppat, Camilla Emilie; Kamphøvener, Sidsel Frederikke; Weis, Malte

    2015-01-01

    Abstract This project seeks to examine how the communication on Tinder and Elitedaters plays out. The difference between the two medias is examined on the background of two focus group interviews with users of the two dating sites. The rhetoric and communication on Tinder and Elitedaters is investigated using an analysis of the pictures and the profile text of different user profiles. Users of the dating sites must win peoples’ sympathy and interest by building up a big ethos appeal. Th...

  5. Date restricted queries in web search engines

    OpenAIRE

    Lewandowski, Dirk

    2004-01-01

    Search engines usually offer a date restricted search on their advanced search pages. But determining the actual update of a web page is not without problems. We conduct a study testing date restricted queries on the search engines Google, Teoma and Yahoo!. We find that these searches fail to work properly in the examined engines. We discuss implications of this for further research and search engine development.

  6. Luminescence dating applied to medieval architecture

    OpenAIRE

    Bouvier, Armel; Pinto, Grégory; Guibert, Pierre; Nicolas-Méry, David; Baylé, Maylis

    2014-01-01

    Avranches’ keep remains constitute a witness of Anglo-Norman knowledge on castle building. Their similarity with other buildings such as Ivry-la-Bataille castle or London Tower required determining the place of Avranches keep in this group: pioneer or imitation? Therefore, samples of brick for luminescence dating were taken from the remaining little tower. Results indicate a chronology later than assumed: second part of the 12th century and first part of 13th century. These dates tend to prov...

  7. Privacy Risks in Mobile Dating Apps

    OpenAIRE

    Farnden, Jody; Martini, Ben; Choo, Kim-Kwang Raymond

    2015-01-01

    Dating apps for mobile devices, one popular GeoSocial app category, are growing increasingly popular. These apps encourage the sharing of more personal information than conventional social media apps, including continuous location data. However, recent high profile incidents have highlighted the privacy risks inherent in using these apps. In this paper, we present a case study utilizing forensic techniques on nine popular proximity-based dating apps in order to determine the types of data tha...

  8. Dating ancient monuments by nuclear radiation

    International Nuclear Information System (INIS)

    In the fifties and sixties several disciplines dealing with chronologies but lacking precise methods of measurements (geology, biology, archaeology and art history) became aware of the radioactive decay as a tool of measuring elapsed time. Among the disciplines that benefit most from physical methods archaeology has to be named first. So was archaeological work revolutionised by the introduction of the C-14 dating method. A wider selection of material became datable after the introduction of luminescence techniques using the effect of nuclear radiation on semiconductors. These minerals are widespread among archaeological materials. In ancient monuments, the objective of this paper, semiconductors almost exclusively form the material basis. Over the last four millennia wood, stone, mortar and fired bricks have been used for the construction of buildings. After discussing methods taking wood as a dating material, a broader view will be given on the results achieved by luminescence dating of fired bricks, mortar and stone. For many years brick dating was performed by thermoluminescence, the recipes followed those of ceramic dating. Preferably multiple aliquot additive dose protocols were used on polymineral fine grain fractions (1-10 μm). It was expected that the error in dating monuments would be smaller compared to ceramic dating, because of the constancy of the environmental conditions which a brick experiences during its lifetime. However, the variability of firing temperatures in brick kilns overthrows this advantage. Therefore, the demands of art historians to fall short of an error margin of 5% could generally not be fulfilled. Especially in medieval or renaissance times the temporal resolution of thermoluminescence is inferior to traditional stylistic dating as long as specific stylistic forms are present. New optical luminescence techniques and a new philosophy of dose evaluation, based on single aliquot regeneration protocols, produce less scatter, and in

  9. Dating Antarctic soils with atmospherically-produced 10Be

    International Nuclear Information System (INIS)

    Traditionally, dating on-land soils (tills) in Antarctica has proved difficult due to a lack of suitable and reliable methods, and an absence of fixed points by which ages can be accurately determined. Cosmogenic isotopes, in particular 10Be, offer a solution to this problem through the application of surface exposure dating. Surface exposure dating of substrate, bouldery flows or tills can provide useful minimum ages, but is limited by uncertainties regarding production rates, degree of erosion and/or pre-existing snow/soil cover, and tectonism. Dating soils using 10Be has its own set of limitations, but a range of new interpretative approaches has recently yielded some promising results. However, it is difficult to accurately estimate 10Be flux, which can differ by orders of magnitude both spatially and over geological time. Alternatively 10Be/9Be ratios of easily leachable soil components, produced near the soil surface by equilibrium of atmospheric 10Be and common Be (9Be), may be presumed to be independent of 10Be flux. In soil of pH less than 5, this Be becomes relatively mobile and moves downwards slowly over several My, yielding 10Be/9Be decay curves from which age information can be inferred. An even more promising approach relies on an observed close correlation between 10Be ages, independent age estimations and nitrate inventories. The nitrate, like 10Be, is derived from chemical reactions in the stratosphere and is known to gradually accumulate with time in Antarctic soils as part of the total salt inventory. Evidence suggests that nitrate flux into the soils may be temporally and spatially constant. This suggests that, if they can be independently age calibrated (using 10Be/9Be), nitrate inventories could provide a reliable and widely applicable estimate of soil ages in Antarctica

  10. Bullying Predicts Reported Dating Violence and Observed Qualities in Adolescent Dating Relationships.

    Science.gov (United States)

    Ellis, Wendy E; Wolfe, David A

    2015-10-01

    The relationship between reported bullying, reported dating violence, and dating relationship quality measured through couple observations was examined. Given past research demonstrating similarity between peer and dating contexts, we expected that bullying would predict negative dating experiences. Participants with dating experience (n = 585; 238 males, M(age) = 15.06) completed self-report assessments of bullying and dating violence perpetration and victimization. One month later, 44 opposite-sex dyads (M(age) = 15.19) participated in behavioral observations. In 10-min sessions, couples were asked to rank and discuss areas of relationship conflict while being video-recorded. Qualities of the relationship were later coded by trained observers. Regression analysis revealed that bullying positively predicted dating violence perpetration and victimization. Self-reported bullying also predicted observations of lower relationship support and higher withdrawal. Age and gender interactions further qualified these findings. The bullying of boys, but not girls, was significantly related to dating violence perpetration. Age interactions showed that bullying was positively predictive of dating violence perpetration and victimization for older, but not younger adolescents. Positive affect was also negatively predicted by bullying, but only for girls. These findings add to the growing body of evidence that adolescents carry forward strategies learned in the peer context to their dating relationships. PMID:25355858

  11. Development of BASIC program for radiocarbon dating

    International Nuclear Information System (INIS)

    The continuous improvement of the system and the needs have produced the successful radiocarbon dating system of today to detect very low energy β-radioactivity. However, it still takes longer than 1,000 minutes for a sample counting. In a gas counting system, it is very difficult to keep the drift of impressed high voltage for a proportional counter less than 5 volts throughout the counting time. The temperature and the characteristics of gas itself also change during experiment. The accumulation of the above drift and errors are closely concerned with the accuracy and reliability of the radiocarbon date. The detection and reduction of the errors are only possible by using a ''fully automatic radiocarbon dating system'' linked to a personal computer system. In this paper, the author presents the BASIC (Beginners All-purpose Symbolic Instruction Code) program for a fully automatic radiocarbon dating system. In this paper, the outline of the system and software development are described. The details of the program include the description for gas-collection, gas-enclosing, plateau counting, β-ray counting, age calculation and data file maintenance. The author wrote numerous remark statements into the program so that it can be understood by users without detailed knowledge of the operation of a personal computer system or of the radiocarbon dating. Using this system, the author found that the radiocarbon dating has greatly progressed in speed and labour-saving, and that the accuracy and reliability of the date itself has also improved much than former manual systems. (Wakatsuki, Y.)

  12. The impact on archaeology of radiocarbon dating by accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Radiocarbon dating by accelerator mass spectrometry (AMS) is based on direct determination of the ratio of 14C: 12C atoms rather than on counting the radioactivity of 14C. It is therefore possible to measure much lower levels of 14C in a sample much more rapidly than the conventional technique allows. Consequently, minimum sample size is reduced approximately 1000-fold and the datable time span of the method can, theoretically, be doubled. Greater selectivity, in the field and the laboratory, is the most important archaeological attribute of AMS 14C dating. It allows on-site chronological consistency to be tested by multiple sampling; archaeological materials to be dated that contain too little C, or are too rare or valuable, to be dated by the conventional method; and the validity of a date to be tested by isolating and independently dating particular fractions in chemically complex samples. In this paper, recent archaeological applications of the new technique are reviewed under these two headings: verification dating applied to the origin and spread of anatomically modern humans in Europe and the Americas, to putative evidence for early (pre-Neolithic) agriculture in Israel and Egypt, and to the dating of rare Palaeolithic and later artefacts; and the building of new and more-detailed chronologies illustrated by reference to Upper Palaeolithic sequences in Europe, Mesolithic-Neolithic sequences in Southwest Asia, and Neolithic-Bronze Age chronologies in Britain. (author)

  13. Exploration of making date seed’s flour and its nutritional contents analysis

    Science.gov (United States)

    Wahini, M.

    2016-04-01

    The date palm (Phoenix dactylifera L) is one of the oldest fruit plants that identical with people’s lives in the Middle East including The Kingdom of Saudi Arabia since ancient times.The date palm is known and consumed by most of people in the form of fruit flesh, while its seed is discarded tough it is rich in nutrient. Therefore, need to be explored the potential of date seed through product innovation of foodstuffs with a high nutritional value. The aims of this study were to 1) know how to make flour from date seed, and 2) determine nutritional content of date seed’s flour. This study was experiment and conducted in July, 2015 at the laboratory of food technology, Family Welfare Education department. Chemical analysis was used to determine nutrients content. The results showed that 1) the flour of date seed produced from the process of washing, soaking, flushing, boiling, draining, drying, grinding, and sieving; 2) the flour of date seed’s flour have a macro nutrients value. This study explains that date seed is regarded as rubbish, in fact, it has a high value that can be an alternative substitution of wheat flour.

  14. Chemical networks*

    OpenAIRE

    Thi Wing-Fai

    2015-01-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One o...

  15. Aggressive events in adolescent dating violence.

    Science.gov (United States)

    Draucker, Claire Burke; Martsolf, Donna; Stephenson, Pamela; Risko, Judy; Heckman, Terri; Sheehan, Denice; Perkins, Shannon; Washington, Kalisha; Cook, Christina; Ferguson, Candice

    2010-09-01

    This purpose of this paper is to present a typology of common aggressive events that occur in the context of adolescent dating violence. The typology is based on 42 transcripts of interviews with young adults, ages 18 to 21, who described dating violence they had experienced when adolescents (ages 13-18). One-hundred and eighty-four text units that contained a description of an event involving aggression or violence between the participant and a dating partner were extracted from the transcripts. Cross-case analysis was used to create categories of events that shared similar characteristics. The analysis yielded eight types of aggressive events: (a) tumultuous, (b) explosive, (c) scuffling, (d) violating, (e) threatening, (f) controlling, (g) disparaging, and (h) rejecting, ignoring, or disrespecting. The typology can provide a foundation for further research on adolescent dating violence from a situational perspective and can be used as a tool to promote discussion of dating violence with victimized or at-risk youth. PMID:20701423

  16. OU3 sediment dating and sedimentation rates

    International Nuclear Information System (INIS)

    Environmental Technologies at Rocky Flats Environmental Technology Site (RFS) investigated the sediment history of Standley Lake, Great Western Reservoir, and Mower Reservoir using 137Cs and 239,240Pu global fall-out as dating indicators. These Colorado Front Range reservoirs have been the subject of study by various city, state and national agencies due to suspected Department of Energy Rocky Flats Plant impacts. We performed sediment dating as part of the RCRA Facility Investigation/Remedial Investigation Report for Operable Unit 3. A sediment chronology profile assists scientist in determining the year of sedimentation for a particular peak concentration of contaminants. Radioisotope sediment dating for the three reservoirs indicated sedimentation rates of 0.7 to 0.8 in./yr. for Standley Lake (SL), 0.9 in./yr. for Great Western Reservoir (GWR), and 0.3 in./yr. in Mower Reservoir (MR). RFS sediment dating for Operable Unit 3 compared favorably with the Hardy, Livingston, Burke, and Volchok Standley Lake study. This report describes the cesium/plutonium sediment dating method, estimates sedimentation rates for Operable Unit 3 reservoirs, and compares these results to previous investigations

  17. Radiocarbon dating of ancient Japanese documents

    International Nuclear Information System (INIS)

    History is a reconstruction of past human activity, evidence of which is remained in the form of documents or relics. For the reconstruction of historic period, the radiocarbon dating of ancient documents provides important information. Although radiocarbon age is converted into calendar age with the calibration curve, the calibrated radiocarbon age is still different from the historical age when the document was written. The difference is known as 'old wood effect' for wooden cultural property. The discrepancy becomes more serious problem for recent sample which requires more accurate age determination. Using Tandetron accelerator mass spectrometer at Nagoya University, we have measured radiocarbon ages of Japanese ancient documents, sutras and printed books written dates of which are clarified from the paleographic standpoint. The purpose is to clarify the relation between calibrated radiocarbon age and historical age of ancient Japanese document by AMS radiocarbon dating. This paper reports 23 radiocarbon ages of ancient Japanese documents, sutras and printed books. The calibrated radiocarbon ages are in good agreement with the corresponding historical ages. It was shown by radiocarbon dating of the ancient documents that Japanese paper has little gap by 'old wood effect'; accordingly, ancient Japanese paper is a suitable sample for radiocarbon dating of recent historic period. (author)

  18. Date attachable offline electronic cash scheme.

    Science.gov (United States)

    Fan, Chun-I; Sun, Wei-Zhe; Hau, Hoi-Tung

    2014-01-01

    Electronic cash (e-cash) is definitely one of the most popular research topics in the e-commerce field. It is very important that e-cash be able to hold the anonymity and accuracy in order to preserve the privacy and rights of customers. There are two types of e-cash in general, which are online e-cash and offline e-cash. Both systems have their own pros and cons and they can be used to construct various applications. In this paper, we pioneer to propose a provably secure and efficient offline e-cash scheme with date attachability based on the blind signature technique, where expiration date and deposit date can be embedded in an e-cash simultaneously. With the help of expiration date, the bank can manage the huge database much more easily against unlimited growth, and the deposit date cannot be forged so that users are able to calculate the amount of interests they can receive in the future correctly. Furthermore, we offer security analysis and formal proofs for all essential properties of offline e-cash, which are anonymity control, unforgeability, conditional-traceability, and no-swindling. PMID:24982931

  19. Thermoluminescence dating in the Soviet Union

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) dating of deposits is performed in the Soviet Union in three laboratories using widely differing techniques. 1. In the Institute of Geology of the Academy of Sciences of the Ukrainian SSR the investigators work with a polymineral fraction of 10-100 μm. In estimating age they make several methodical mistakes. The dating interval covered is 2x104-106 years. 2. In Moscow State University the scientists use the quartz fraction up to 250 μm without etching by HF. Using a complicated mathematical treatment of graphical results of dating, the authors come to the conclusion that their technique enables them to date deposits in the time interval 4x103-9.5x106 years. 3. In the Institute of Geology of the Academy of Sciences of the Estonian SSR, the quartz and feldspar inclusion technique is used. It is shown that quartz enables the dating of deposits to be made up to 105 years in age, and preliminary results indicate that with feldspars the age limit is 7x105 years. (author)

  20. Internet dating as a project: the commodification and rationalisation of online dating:

    OpenAIRE

    Tjaša Žakelj; Doris Kocon; Alenka Švab; Roman Kuhar

    2015-01-01

    Based on qualitative empirical data from two studies on Internet dating in Slovenia, this paper discusses the social contexts of the Internet dating of heterosexual men and women and homosexual men. Special attention is given to different aspects of the commodification and rationalisation of dating in the process of forming potential (romantic) partnerships. First, we discuss our respondents' reasons for using the Internet to get in touch with potential (romantic) partners. Second, we focus o...

  1. Geological Survey of Canada radiocarbon dates XXIX

    International Nuclear Information System (INIS)

    This list presents 622 radiocarbon age determinations made by the Radiocarbon Dating Laboratory. All samples dated more than two years ago have now been reported in date lists. The total number (609) of samples from various areas are as follows: Offshore (43); Newfoundland (42); Labrador (11); Nova Scotia (39); New Brunswick (7); Champlain Sea (38); Quebec (54); Ontario (23); Manitoba (3); Saskatchewan (9); Alberta (6); British Columbia (92); Yukon Territory (71); Northwest Territories, mainland (33); Northwest Territories, Arctic Archipelago (126); U.S.A. - New York (6); Washington (1); Denmark Greenland (3). Tables 1 and 2 summarize the details of background and standard counts for the 2 L and 5 L counters during the period from December 6, 1988 to January 9, 1990. (author). Refs

  2. Radiocarbon dating with accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Radiocarbon dating by means of accelerator mass spectrometry (AMS) has two great advantages over conventional dating: 1) much smaller samples can be handled and 2) counting time is significantly shorter. Three examples are given for Holocene-age material from east-central Ellesmere Island. The results demonstrate the potential use of this technique as a powerful research tool in studies of Quaternary chronology. Individual fragments of marine shells as small as 0.1 g have been dated successfully at the IsoTrace Laboratory, University of Toronto. In the case of an aquatic moss from a lake sediment core, an increment 0.5 cm thick could be used instead of a 5 cm-thick slice, thus allowing a much more precise estimate of the onset of organic sedimentation

  3. Chemical machining

    OpenAIRE

    A. Yardimeden; T. Ozben; O. Cakir

    2007-01-01

    Purpose: Nontraditional machining processes are widely used to manufacture geometrically complex and precision parts for aerospace, electronics and automotive industries. There are different geometrically designed parts, such as deep internal cavities, miniaturized microelectronics and fine quality components may only be produced by nontraditional machining processes. This paper is aiming to give details of chemical machining process, industrial applications, applied chemical etchants and mac...

  4. Chemical Radioprotectors

    Directory of Open Access Journals (Sweden)

    S. N. Upadhyay

    2005-10-01

    Full Text Available Protection of biological systems against radiation damage is of paramount importance during accidental and unavoidable exposure to radiation. Several physico-chemical and biological factors collectively contribute to the damage caused by radiation and are, therefore, targets for developing radioprotectors. Work on the development of chemicals capable of protecting biological systemsfrom radiation damage was initiated nearly six decades ago with cysteine being the first molecule to be reported. Chemicals capable of scavenging free radicals, inducing oxygen depletion,antioxidants and modulators of immune response have been some of the radioprotectors extensively investigated with limited success. Mechanism of action of some chemical radioprotectors and their combinations have been elucidated, while further understanding is required in many instances. The present review elaborates on structure-activity relationship of some of the chemical radioprotectors, their evaluation, and assessment, limitation, and future prospects.

  5. ESR dating of teeth from Brazilian megafauna

    Science.gov (United States)

    Oliveira, L. C.; Kinoshita, A.; Barreto, A. M. F.; Figueiredo, A. M.; Silva, J. L. L.; Baffa, O.

    2010-11-01

    The study of radiation defects created in biomaterials, such as bone and teeth, can be used in dating with importance to palaeontology and archaeology. Two Stegomastodon teeth (AL1 and AL2) from north-eastern Brazilian megafauna were studied by electron spin resonance (ESR) spectroscopy. The samples were collected in Fazenda Ovo da Ema, (913349 / 3714965) UTM, Alagoas state, Brazil. The dating of these samples can contribute to the better knowledge of megafauna presence in this region as well as to the events associated to the extinction of these species.

  6. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    case studies will show the degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants and animals, shows that age differences of up to 2000 years can occur within one river. In the Limfjord, freshwater influence...... caused reservoir ages to vary between 250 and 700 years during the period 5400 BC - AD 700. Finally, I will discuss the implications of the freshwater reservoir effect for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany....

  7. Thermoluminescence dating of Scottish vitrified forts

    International Nuclear Information System (INIS)

    The dating programme on Scottish vitrified forts has been continued. Implementation of a microscopic inspection for grains, which individually are a mixture of minerals fused together during vitrification has improved the purity of the mineral fractions following heavy liquid separation. In potassium feldspar grains from material being crushed using considerable force, there was found to be no occurrence of tribo-thermoluminescence that could not be removed by standard procedures. The inclusion technique used failed to give reproducible results for basic rocks. For other rocks the preliminary results were promising. Preliminary dates for the sites Mote of Mark, Kemp Law, Portencross and Dundonald are presented. (author)

  8. Thermoluminescence dating of old copper slags

    International Nuclear Information System (INIS)

    By means of the thermoluminescence method applied to copper slags, copper smelting sites in Turkey, Greece, Jordan, and the Federal Republic of Germany were dated. The samples for thermoluminescence dating were prepared in the same way as for the fine grain method. For the analysis of the radioactive components the following methods were applied: atomic absorption spectrometry, alpha counting, instrumental neutron activation analysis, gamma spectroscopy and fission track mapping. The calculation of the thermoluminescence ages was based on the assumption that the radioactive elements and thermoluminescence phosphorus are uniformly distributed in the slags. (DG)

  9. The TL dating of ancient porcelain

    International Nuclear Information System (INIS)

    The age determination of ancient porcelain using the pre-dose technique in TL dating was reported. The variation of beta dose with depth below the surface of the porcelain slice, the thermal activation characteristic (TAC) for 110 degree C peak, the measurement of paleodose and the estimation of annual dose were studied. The results show that this technique is suitable for authenticity testing of ancient porcelain, but both accuracy and precision for porcelain dating are worse than those for pottery, because porcelain differs from pottery on composition, structure and firing temperature. Besides, some complicated factors in the pre-dose technique would be the possible cause of the greater errors

  10. Dating and characterization of archaeological ceramics of the Araruama area at Rio de Janeiro, Brazil

    International Nuclear Information System (INIS)

    Ceramic of three archaeological sites (Serrano, Morro Grande, and condominium Bela Vista) of the Araruama area (Rio de Janeiro/Brazil), are being dated by the thermoluminescence technique. These ceramics are being characterized, in your elementary chemical composition, by INAA. Preliminary results are presented and the samples treatment method is described. (author)

  11. 46 CFR 115.310 - Certification expiration date stickers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Certification expiration date stickers. 115.310 Section... expiration date stickers. (a) A Certification Expiration Date Sticker indicates the date upon which the... Expiration Date Sticker affixed to the vessel on a place that is: (1) A glass or other smooth surface...

  12. Isotopic studies of the Eye-Dashwa Lakes pluton and the long-term integrity of whole-rock and mineral systems

    International Nuclear Information System (INIS)

    This report presents results of isotopic studies of the Eye-Dashwa Lakes pluton, located near Atikokan, Ontario. Suites of pristine unaltered and highly altered core samples from deep boreholes were used to study Rb-Sr, U-Th-Pb and Sr-Nd systematics, whole-rock Pb isotopes and fission track dating of apatite. The results have been used to investigate natural analogues for radionuclide migration in the geosphere, the tectonic stability of the pluton and the extent of water-rock interaction in fracture zones

  13. Applications of different dose of irradiation on dates followed by quality parameters

    International Nuclear Information System (INIS)

    The objective of this project is to evaluate the effects of radiation on the conservation of dates and the development of micro-organisms. Deglet Nour variety of dates were purchased from local market and irradiated at doses 0, 0.5, 0.75 and 1 kGy and stored at room temperature for 30 days. During storage, we evaluated the effects of radiation on the evolution of fructose, glucose, sucrose, pH, organic acid and moisture which are parameters of quality of dates. We have also checked its effect on the development on micro-organisms. During storage, there has been a change in the chemical composition and microbiological quality. However, these changes are proportional to the radiation doses applied. 1 kGy dose appears to be the best. It completely inhibits the development of micro-organisms and slows senescence dates. (Author)

  14. REIMEP-22 inter-laboratory comparison. ''U Age Dating - determination of the production date of a uranium certified test sample''

    International Nuclear Information System (INIS)

    The REIMEP-22 inter-laboratory comparison aimed at determining the production date of a uranium certified test sample (i.e. the last chemical separation date of the material). Participants in REIMEP-22 on ''U Age Dating - Determination of the production date of a uranium certified test sample'' received one low-enriched 20 mg uranium sample for mass spectrometry measurements and/or one 50 mg uranium sample for a-spectrometry measurements, with an undisclosed value for the production date. They were asked to report the isotope amount ratios n(230Th)/n(234U) for the 20 mg uranium sample and/or the activity ratios A(230Th)/A(234U) for the 50 mg uranium sample in addition to the calculated production date of the certified test samples with its uncertainty. Reporting of the 231Pa/235U ratio and the respective calculated production date was optional. Eleven laboratories reported results in REIMEP-22. Two of them reported results for both the 20 mg and 50 mg uranium certified test samples. The measurement capability of the participants was assessed against the independent REIMEP-22 reference value by means of z- and zeta-scores in compliance with ISO 13528:2005. Furthermore a performance assessment criterion for acceptable uncertainty was applied to evaluate the participants' results. In general, the REIMEP-22 participants' results were satisfactory. This confirms the analytical capabilities of laboratories to determine accurately the age of uranium materials with low amount of ingrown thorium (young certified test sample). The Joint Research Centre of the European Commission (EC-JRC) organised REIMEP-22 in parallel to the preparation and certification of a uranium reference material certified for the production date (IRMM-1000a and IRMM-1000b).

  15. REIMEP-22 inter-laboratory comparison. ''U Age Dating - determination of the production date of a uranium certified test sample''

    Energy Technology Data Exchange (ETDEWEB)

    Venchiarutti, Celia; Richter, Stephan; Jakopic, Rozle; Aregbe, Yetunde [European Commission, Joint Research Centre (JRC), Geel (Belgium). Institute for Reference Materials and Measurements (IRMM); Varga, Zsolt; Mayer, Klaus [European Commission, Joint Research Centre (JRC), Karlsruhe (Germany). Institute for Transuranium Elements (ITU)

    2015-07-01

    The REIMEP-22 inter-laboratory comparison aimed at determining the production date of a uranium certified test sample (i.e. the last chemical separation date of the material). Participants in REIMEP-22 on ''U Age Dating - Determination of the production date of a uranium certified test sample'' received one low-enriched 20 mg uranium sample for mass spectrometry measurements and/or one 50 mg uranium sample for a-spectrometry measurements, with an undisclosed value for the production date. They were asked to report the isotope amount ratios n({sup 230}Th)/n({sup 234}U) for the 20 mg uranium sample and/or the activity ratios A({sup 230}Th)/A({sup 234}U) for the 50 mg uranium sample in addition to the calculated production date of the certified test samples with its uncertainty. Reporting of the {sup 231}Pa/{sup 235}U ratio and the respective calculated production date was optional. Eleven laboratories reported results in REIMEP-22. Two of them reported results for both the 20 mg and 50 mg uranium certified test samples. The measurement capability of the participants was assessed against the independent REIMEP-22 reference value by means of z- and zeta-scores in compliance with ISO 13528:2005. Furthermore a performance assessment criterion for acceptable uncertainty was applied to evaluate the participants' results. In general, the REIMEP-22 participants' results were satisfactory. This confirms the analytical capabilities of laboratories to determine accurately the age of uranium materials with low amount of ingrown thorium (young certified test sample). The Joint Research Centre of the European Commission (EC-JRC) organised REIMEP-22 in parallel to the preparation and certification of a uranium reference material certified for the production date (IRMM-1000a and IRMM-1000b).

  16. Physical Dating Aggression Growth during Adolescence

    Science.gov (United States)

    Nocentini, Annalaura; Menesini, Ersilia; Pastorelli, Concetta

    2010-01-01

    The development of Physical Dating Aggression from the age of 16 to 18 years was investigated in relation to time-invariant predictors (gender, parental education, family composition, number of partners) and to time-varying effects of delinquent behavior and perception of victimization by the partner. The sample consisted of 181 adolescents with a…

  17. Radiocarbon Dating of Vertisols in China

    Institute of Scientific and Technical Information of China (English)

    LIULIANGWU

    1996-01-01

    Vertisols,which are mainly developed on fluvial and lacustrine deposits and basalt,are extensively distributed in China.66 samples of them for radiocarbon dating were collected across 5 porvinces and 1 autonomous region,ranging from warm-temperate to subtropical and tropical zones in China.The soil organic matter was dated via surface horizon,black soil horizon and dark-colour horizon of the vertisols,whereas carbonate through calcareous concretions and dispersed carbonate in soil profile using radiocarbon method.The present article elucidates the dates of genetic horizons,and of surface and buried vertisols as well.14C dating indicates that the surface vertisols were formed during the end of the late Pleistocene.ca.15600 years ageo.Correlation between depth of sampling and measured 14C age shows that age characteristics of the vertisols of China are close to those of West Germany,Italy,TUrnisia,Australia and Argentina,However,two buried vertisols developed on fluvial and lacustrine deposits were formed during different geological periods,The buried soils in warm-temperate zone were formed in the mid Holocene,while those in subtropics were buried at 12930 years B.P., and formed in the end of the late Pleistocene.

  18. Use of radiocarbon technique for archaelogic dating

    International Nuclear Information System (INIS)

    The nuclear technique based on the beta radiation measurements emitted by the radiocarbon is applied an the geochronologycal dating of organic samples of prehistoric fires and sambaqui shells. This paper describes the origin of the method, the technique used and its applications, the analysis method, the equipments and the experiences performed. (Author)

  19. The puzzle of dating the Santorini eruption

    International Nuclear Information System (INIS)

    Full text: Some 3500 years ago the Aegean island of Thera (modern Santorini) exploded in a cataclysmal volcanic eruption. This event provides, in principle, a distinct time marker in the Second Millennium B.C. An exact date would be of particular importance for the synchronization of ancient civilizations in the East Mediterranean in this time period. However, despite great efforts from different fields there is no consensus on the date. In essence, new 14C dating measurements determined the eruption to a period between 1650 to 1600 B.C., whereas archaeological evidence linked to the Egyptian historical chronology favors a date well after the beginning of the New Kingdom in Egypt (1530 B.C.). Although the difference of 100 to 140 years translates into an uncertainty of only 3 to 4 % in the absolute age of the eruption, it is nevertheless decisive for a correct understanding of the interactions of cultures in this time period. The radiocarbon evidence and the prospects of identifying Thera eruptive material in ice cores from Greenland - at present also controversial - will be discussed. (author)

  20. Screening Practices for Adolescent Dating Violence

    Science.gov (United States)

    Brown, Larry K.; Puster, Kristie L.; Vazquez, Elizabeth A.; Hunter, Heather L.; Lescano, Celia M.

    2007-01-01

    This study sought to determine the screening practices of child and adolescent psychiatrists regarding adolescent dating violence (DV). A questionnaire regarding screening practices for DV and other risk behaviors was administered to 817 child and adolescent psychiatrists via the Internet and mail. Twenty-one percent of clinicians screened for DV…

  1. 38 CFR 21.9625 - Beginning dates.

    Science.gov (United States)

    2010-07-01

    ...) (b) Certification for program of education that leads to a standard college degree. (1) When the... that does not lead to a standard college degree. (1) When an eligible individual enrolls at an... to a standard college degree, the beginning date of the award of educational assistance will be...

  2. Teaching Interactionist Gender Theory through Speed Dating

    Science.gov (United States)

    Messinger, Adam M.

    2015-01-01

    Few evaluated classroom exercises to date have addressed one of the most cited and compelling explanations of gender formation over the life course: interactionist gender theory. This theory posits that people actively "do" or "perform" their gender in every interaction, and as such, they often subconsciously reshape their…

  3. Radiocarbon dating of interlaboratory check samples

    International Nuclear Information System (INIS)

    This note presents the results of a series of interlaboratory age determinations in which the Geological Survey of Canada's Radiocarbon Dating Laboratory has been involved. There is good agreement between laboratories, although there may be other problems related to the interpretation of individual samples

  4. Radiocarbon dating of ancient rock paintings

    International Nuclear Information System (INIS)

    This report presents progress made on a technique for 14C dating pictographs. A low-temperature oxygen plasma is used coupled with high-vacuum technologies to selectively remove C-containing material in the paints without contamination from inorganic carbon from rock substrates or accretions

  5. Dating brittle tectonic movements with cleft monazite

    DEFF Research Database (Denmark)

    Berger, Alfons; Gnos, E.; Janots, E.; Whitehouse, M.; Soom, M.; Frei, Robert; Waight, Tod Earle

    2013-01-01

    phases. This allows the high precision isotope dating of cleft monazite. 232Th/208Pb ages are not affected by excess Pb and yield growth domain ages between 8.03 ± 0.22 Ma and 6.25 ± 0.60 Ma. Monazite crystallization in brittle structures is coeval or younger than 8 Ma zircon fission track data, and...

  6. 38 CFR 21.7135 - Discontinuance dates.

    Science.gov (United States)

    2010-07-01

    ..., 3683, Pub. L. 98-525) (p) Incarceration in prison or penal institution for conviction of a felony. (1... incarcerated in prison or penal institution, or (iii) The comencing date of the award as determined by § 21... quarter or semester system exhausts his or her entitlement under 38 U.S.C. chapter 30, the...

  7. Study of temperature control for thermoluminescence dating

    International Nuclear Information System (INIS)

    The requirements of the temperature control in thermoluminescence (TL) dating were described briefly. The basic principles of heating control and application design to achieve high accuracy were introduced. Heating curves of RGD-3B TL reader are measured as an applied example, and the results show that high accuracy and good repeatability can be acquired. (authors)

  8. The unexpected truth about dates and hypoglycemia

    Directory of Open Access Journals (Sweden)

    Mohammed I Yasawy

    2016-01-01

    Full Text Available Background: Dates are a concentrated source of essential nutrients, vitamins, minerals, and carbohydrates (CHOs, which are necessary for the maintenance of optimum health. Most of the CHOs in dates come from sugars including glucose and fructose. Dates are commonly consumed in Saudi Arabia, particularly at the time of breaking the fast to provide instant energy and maintain blood sugar level. However, dates may cause hypoglycemia in a rare condition named as heredity fructose intolerance (HFI, and a few families have been to see us with a history of that nature. This is to report the preliminary results of an on-going study of a group of patients who get symptoms of hypoglycemia following the ingestion of dates and have suffered for years without an accurate diagnosis. Methodology: This report is based on three patients, from the same family, living in a date growing region of the Kingdom of Saudi Arabia (KSA. The patients had been to several medical centers without getting any definite answers or diagnosis until they were referred to the Gastroenterology Clinic of King Fahd Hospital of the University, Al-Khobar, KSA. The data were obtained by careful history and laboratory investigations, and a final diagnosis of HFI made on fructose intolerance test (FIT. Results: The patients reported that they had avoided eating dates because of various symptoms, such as bloating, nausea, and even hypoglycemia when larger amounts were consumed. Their other symptoms included sleepiness, sweating, and shivering. After full examinations and necessary laboratory tests based on the above symptoms, FIT was performed and the patients were diagnosed with HFI. They were referred to a dietitian who advised a fructose-free diet. They felt well and were free of symptoms. Conclusion: HFI may remain undiagnosed until adulthood and may lead to disastrous complications and even death. The diagnosis can only be suspected after a careful dietary history is taken supported by

  9. Internet dating as a project: the commodification and rationalisation of online dating

    Directory of Open Access Journals (Sweden)

    Tjaša Žakelj

    2015-04-01

    Full Text Available Based on qualitative empirical data from two studies on Internet dating in Slovenia, this paper discusses the social contexts of the Internet dating of heterosexual men and women and homosexual men. Special attention is given to different aspects of the commodification and rationalisation of dating in the process of forming potential (romantic partnerships. First, we discuss our respondents’ reasons for using the Internet to get in touch with potential (romantic partners. Second, we focus on the demands and strategies of targeted market- ing in personal profile writing and, finally, on the process of selecting potential partners. Our study shows that the primary understanding of Internet dating among people who engage in it is its economic nature. Together with targeted marketing and the predeter- mined criteria for choosing interesting others, Internet dating can thus be understood as a market that encourages rationalisation and commodification in the process of forming intimate relationships.

  10. Witnessing Interparental Violence and Acceptance of Dating Violence as Predictors for Teen Dating Violence Victimization.

    Science.gov (United States)

    Karlsson, Marie E; Temple, Jeff R; Weston, Rebecca; Le, Vi Donna

    2016-04-01

    We examined the association between witnessing interparental violence, attitudes about dating violence, and physical and psychological teen dating violence (TDV) victimization. Participants were 918 teens with dating experience. Witnessing interparental violence and acceptance of dating violence were significant predictors of TDV victimization. Acceptance of dating violence was also a partial mediator between witnessing interparental violence and TDV victimization. Witnessing mother-to-father violence and acceptance of female-perpetrated violence were the most consistent predictors. TDV programs aiming to prevent victimization could benefit from targeting youth exposed to father-to-mother and mother-to-father violence, targeting attitudes about violence, and tailoring interventions to gender-specific risk factors. PMID:26452379

  11. Comparative studies on fumigation and irradiation of semi-dry date fruits

    International Nuclear Information System (INIS)

    The experiment was carried out on Egyptian semidried date fruits 'El-Seidi CV' which use to process paste of dates. It is aimed to compare the effect of irradiation (1.5, 3.0 kGy) and fumigation with methyl bromide (MB) on physical, chemical and mycological characteristics, especially on aflatoxin production during storage for dates for a long period (8 months). Irradiation was more effective than MB for disinfestation of dates, but caused significant loss in weight of dates. No changes were observed in irradiated samples as well as in MB samples in moisture content, pH-values and titratable acidity, but less significant changes were observed in browning and sugars, as well as in the total, reducing or non-reducing sugar/acid ratio. Irradiation (3,0 kGy) was more effective than other treatments for inhibition the growth of fungi and prevention of aflatoxin production in synthetic born media of date fruits. Therefore, the irradiation dose of 3.0 kGy instead of fumigation (MB) can be recommended to keep date fruits in good quality, free from infestation, contamination and safer for human consumption during a long storage period. (author)

  12. Chemical Peels

    Science.gov (United States)

    ... pills, who subsequently become pregnant or have a history of brownish facial discoloration. Scarring Reactivation of cold sores What can I expect after having a chemical peel? All peels require some follow-up care: ...

  13. Unnecessary Chemicals

    Science.gov (United States)

    Johnson, Anita

    1978-01-01

    Discusses the health hazards resulting from chemical additions of many common products such as cough syrups, food dyes, and cosmetics. Steps being taken to protect consumers from these health hazards are included. (MDR)

  14. Chemical kinetics

    International Nuclear Information System (INIS)

    This book gives descriptions of chemical kinetics. It starts summary of chemical kinetics and reaction mechanism, and explains basic velocity law, experiment method for determination of reaction velocity, temperature dependence of reaction velocity, theory of reaction velocity, theory on reaction of unimolecular, process of atom and free radical, reaction in solution, catalysis, photochemical reaction, such as experiment and photochemical law and rapid reaction like flame, beam of molecule and shock tube.

  15. ANALYSIS OF OUT OF DATE MCU MODIFIER LOCATED IN SRNL

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C.

    2014-10-22

    SRNL recently completed density measurements and chemical analyses on modifier samples stored in drums within SRNL. The modifier samples date back to 2008 and are in various quantities up to 40 gallons. Vendor information on the original samples indicates a shelf life of 5 years. There is interest in determining if samples that have been stored for more than the 5 year shelf life are still acceptable for use. The Modular Caustic Side Solvent Extraction Unit (MCU) Solvent component Cs-7SB [(2,2,3,3- tetraflouropropoxy)-3-(4-sec-butylphenoxy)-2-propanol, CAS #308362-88-1] is used as a diluent modifier to increase extractant solubility and provide physical characteristics necessary for diluent trimming.

  16. Optical dating of potteries excavated from Pungnabtoseong earthen wall, Seoul

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myung Jin; Park, Mi Seon [Neosiskorea Co., Daejeon (Korea, Republic of); Lee, Sung Joon; Nah, Hye Rim; Hong, Hyung Woo [National Research Institute of Cultural Heritage, Daejeon (Korea, Republic of)

    2012-05-15

    Thermoluminescence (TL) and optically stimulated luminescence (OSL) emitted from natural crystalline mineral, usually quartz, feldspar, and so on, are mainly used to evaluate the paleodose for the age determination of archaeological and geological sample and the equivalent dose for retrospective dosimetry. TL/OSL age can be calculated as the ratio of paleodose to total annual dose rate which is determined from surrounding soil. In this study, we chemically extracted the quartz samples from potteries excavated in Pungnabtoseong earthen wall and observed the TL/OSL characteristics for paleodose determination. With the converted annual dose rate from the concentration of radioactive isotopes in its surrounding soil, optical date was evaluated and finally illustrated for interpreting the construction stage of Pungnabtoseong

  17. Zircon crytallization and recycling in the magma chamber of the rhyolitic Kos Plateau Tuff (Aegean arc)

    Science.gov (United States)

    Bachman, O.; Charlier, B.L.A.; Lowenstern, J. B.

    2007-01-01

    In contrast to most large-volume silicic magmas in continental arcs, which are thought to evolve as open systems with significant assimilation of preexisting crust, the Kos Plateau Miff magma formed dominantly by crystal fractionation of mafic parents. Deposits from this ??? 60 km3 pyroclastic eruption (the largest known in the Aegean arc) lack xenocrystic zircons [secondary ion mass spectrometry (SIMS) U-Pb ages on zircon cores never older than 500 ka] and display Sr-Nd whole-rock isotopic ratios within the range of European mantle in an area with exposed Paleozoic and Tertiary continental crust; this evidence implies a nearly closed-system chemical differentiation. Consequently, the age range provided by zircon SIMS U-Th-Pb dating is a reliable indicator of the duration of assembly and longevity of the silicic magma body above its solidus. The age distribution from 160 ka (age of eruption by sanidine 40Ar/39Ar dating; Smith et al., 1996) to ca. 500 ka combined with textural characteristics (high crystal content, corrosion of most anhydrous phenocrysts, but stability of hydrous phases) suggest (1) a protracted residence in the crust as a crystal mush and (2) rejuvenation (reduced crystallization and even partial resorption of minerals) prior to eruption probably induced by new influx of heat (and volatiles). This extended evolution chemically isolated from the surrounding crust is a likely consequence of the regional geodynamics because the thinned Aegean microplate acts as a refractory container for magmas in the dying Aegean subduction zone (continent-continent subduction). ?? 2007 Geological Society of America.

  18. Zircon crystallization and recycling in the magma chamber of the rhyolitic Kos Plateau Tuff (Aegean arc)

    Science.gov (United States)

    Bachman, O.; Charlier, B.L.A.; Lowenstern, J. B.

    2007-01-01

    In contrast to most large-volume silicic magmas in continental arcs, which are thought to evolve as open systems with significant assimilation of preexisting crust, the Kos Plateau Tuff magma formed dominantly by crystal fractionation of mafic parents. Deposits from this ~60 km3 pyroclastic eruption (the largest known in the Aegean arc) lack xenocrystic zircons [secondary ion mass spectrometry (SIMS) U-Pb ages on zircon cores never older than 500 ka] and display Sr-Nd whole-rock isotopic ratios within the range of European mantle in an area with exposed Paleozoic and Tertiary continental crust; this evidence implies a nearly closed-system chemical differentiation. Consequently, the age range provided by zircon SIMS U-Th-Pb dating is a reliable indicator of the duration of assembly and longevity of the silicic magma body above its solidus. The age distribution from 160 ka (age of eruption by sanidine 40Ar/39Ar dating; Smith et al., 1996) to ca. 500 ka combined with textural characteristics (high crystal content, corrosion of most anhydrous phenocrysts, but stability of hydrous phases) suggest (1) a protracted residence in the crust as a crystal mush and (2) rejuvenation (reduced crystallization and even partial resorption of minerals) prior to eruption probably induced by new influx of heat (and volatiles). This extended evolution chemically isolated from the surrounding crust is a likely consequence of the regional geodynamics because the thinned Aegean microplate acts as a refractory container for magmas in the dying Aegean subduction zone (continent-continent subduction).

  19. Chemical Production using Fission Fragments

    International Nuclear Information System (INIS)

    Some reactor design considerations of the use of fission recoil fragment energy for the production of chemicals of industrial importance have been discussed previously in a paper given at the Second United Nations International Conference on the Peaceful Uses of Atomic Energy [A/Conf. 15/P.76]. The present paper summarizes more recent progress made on this topic at AERE, Harwell. The range-energy relationship for fission fragments is discussed in the context of the choice of fuel system for a chemical production reactor, and the experimental observation of a variation of chemical effect along the length of a fission fragment track is described for the irradiation of nitrogen-oxygen mixtures. Recent results are given on the effect of fission fragments on carbon monoxide-hydrogen gas mixtures and on water vapour. No system investigated to date shows any outstanding promise for large-scale chemical production. (author)

  20. Thermoluminescence dating of quaternary sediments and paleolithic sites

    International Nuclear Information System (INIS)

    The loess chronology of the latest glacial periods was established in great detail by thermoluminescence dating. Horizons containing Middle and Upper Palaeolithic finds were successfully dated. (orig.)

  1. The Nordic laboratory for thermoluminescence dating

    International Nuclear Information System (INIS)

    Thermoluminescence dating is based primarily on the minerals quartz and feldspar which are present in most sedimentary deposits and in many materials of archaeological interest, e.g. ceramics and tile. In nature the two minerals are affected by the radiation to which they are exposed from the omnipresent naturally occurring radioactive elements uranium, thorium and potassium. The radiation transfers energy to electrons which enables them to wander through the crystal. Some will be trapped at localities, called traps, where there are imperfections in the crystal, for example a missing negative ion. The number of trapped electrons is a measure of the radiation dose absorbed by the material. For minerals in Nature the number will also be related to the time elapsed since the traps were last emptied because one can assume that the intensity of the natural background radiation has been constant over the period relevant for TL dating, about one million years. The radiation dose accumulated in quartz and feldspar can be determined by heating the minerals to a temperature of about 500 deg. C. The heating will enable the trapped electrons to escape and return to their ground level. The energy liberated will be emitted as a blue/biolet light called thermoluminescence (abbreviated TL). The ligth signal from natural samples is compared with that emitted by samples which have been given a known dose of radiation in the laboratory. In this way the unknown dose absorbed by the minerals in Nature can be determined. Archeological materials datable by TL include ceramics, bricks and burnt clay from kilns and house walls, and burnt stones. Treatment of samples and dating procedure is described as is also the determination of background and beta radiation. TL dating can be applied over a time span ranging from the present to approximately 500.000 years, uncertainty varies from 50 to 200-300 years. An account is given of some of the major TL dating projects already undertaken by the

  2. Evaluation of the commercial FBR introduction date

    International Nuclear Information System (INIS)

    This report examines one criterion for introducing a commercial FBR: economic competitiveness with a Light Water Reactor (LWR). For this analysis, the commercial FBR is assumed to be the fifth-of-a kind replicate which represents an economically mature plant. This FBR is deemed economically competitive when its life-cycle energy cost is less than or equal to that of an LWR. Results of this analysis are used in a comparative analysis of alternative FBR development stategies. The strategies evaluated in these studies assume both 1000- and 1457-MWe FBRs. Since the capital costs per kilowatt, and therefore the energy costs, for these two FBR sizes are different, they will become economically competitive at different times. The probability density function for the 1457-MW(e) FBR has an expected value date or weighted average date of 2030, compared with 2033 for the probability density function for the 1000-MW(e) FBR

  3. Tolerance towards dating violence in Spanish adolescents.

    Science.gov (United States)

    Rodríguez Francos, Luis; Antuña Bellerín, María de los Ángeles; López-Cepero Borrego, Javier; Rodríguez Díaz, Francisco Javier; Bringas Molleda, Carolina

    2012-05-01

    The study of intimate partner violence among adolescent and young couples in Spain remains unattended, although such abuses are well known and more frequent than in adulthood. The aim of this study is, on the one hand, to provide epidemiological information on dating relationships, and on the other hand, to identify attitudes towards violence. 2205 women enrolled in schools in diverse provinces of Spain, participated in the study. Average age was near 19 years (SD= 2.25). The Dating Violence Questionnaire (DVQ, in Spanish, CUVINO), a questionnaire that assesses both frequency and distress associated with violent behavior, was used. The DVQ allowed differentiating between groups of women self-labeled as abused and not abused on the basis of the frequency of sustained violence, although the levels of distress in the face of violence were statistically similar in both groups. Implications for future research and prevention programs are discussed. PMID:22420351

  4. Optoelectronic date acquisition system based on FPGA

    Science.gov (United States)

    Li, Xin; Liu, Chunyang; Song, De; Tong, Zhiguo; Liu, Xiangqing

    2015-11-01

    An optoelectronic date acquisition system is designed based on FPGA. FPGA chip that is EP1C3T144C8 of Cyclone devices from Altera corporation is used as the centre of logic control, XTP2046 chip is used as A/D converter, host computer that communicates with the date acquisition system through RS-232 serial communication interface are used as display device and photo resistance is used as photo sensor. We use Verilog HDL to write logic control code about FPGA. It is proved that timing sequence is correct through the simulation of ModelSim. Test results indicate that this system meets the design requirement, has fast response and stable operation by actual hardware circuit test.

  5. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    2013-01-01

    The freshwater reservoir effect can result in anomalously old radiocarbon ages of samples from lakes and rivers. This includes the bones of people whose subsistence was based on freshwater fish, and pottery in which fish was cooked. Water rich in dissolved ancient calcium carbonates, commonly known...... order of magnitude and degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants, and animals, shows that age differences of up to 2000 14C years can occur within one river. The freshwater reservoir effect has also...... implications for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany. The surprisingly old ages of the earliest pottery most probably are caused by a freshwater reservoir effect. In a sediment core from the Limfjord, northern Denmark, the impact of the...

  6. Annual dose rate calculations for thermoluminescence dating

    International Nuclear Information System (INIS)

    Tabulations of decay data and dose rate calculations that are necessary for TL dating are presented. An effort has been made to collect the latest evaluated data and to catalog them in a form that is easily accessible, so that they may be updated as new revised values are reported. It is suggested that the largest error in thermoluminescence dating will come from sources other than the tabulated particle energies and branching ratios. These include: (a) the alpha to beta thermoluminescence efficiency determination; (b) concentration measurements of K, Rb, Th, and U; (c) all departures from secular equilibrium in the uranium and thorium decay chains; and (d) the imprecise calibration of laboratory radiation sources

  7. Thermoluminescence dating of partially bleached sediments

    International Nuclear Information System (INIS)

    A major problem in TL dating of sediments is the lack of knowledge concerning the degree of bleaching that took place during transport of the material prior to deposition. A method is proposed that may enable partially bleached sediments to be dated by determining the correct residual value to be used with the build-up curve. The method uses a combination of results for quartz and feldspar, presuming that these two minerals have the same age. Samples are bleached by sunlight for different periods, and the correct bleaching time is taken as that producing residual values which yield identical ages for the minerals. Preliminary results for a number of aeolian sediments from Jutland are presented. In most cases the TL ages were in acceptable agreement with expected ages. (author)

  8. Towards Luminescence Dating Of Mosaic Glass

    Science.gov (United States)

    Galli, A.; Martini, M.; Sibila, E.; Villa, I.

    The possibility of dating archaeological glass by means of luminescent techniques has been investigated in recent years, despite the difficulties of this application, mainly linked to the amorphous structure of the material. We focused in particular on mosaic glass, after the encouraging results obtained on byzantine and medieval samples. Further studies were devoted to the comprehension of the luminescent mechanisms in silica glasses, and to the investigation of the relationships between luminescence, colouring or opacifier ions and crystalline phase of the vitreous matrix. The results of a study on the dosimetric characteristics of thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) of a few medieval blue-green mosaic glasses from the San Lorenzo church (Milan) are presented, and the experimental protocols established to identify their suitability for dating are discussed.

  9. Luminescence dating of ancient Darhad basin, Mongolia

    Science.gov (United States)

    Cheul Kim, Jin; Yi, Sangheon; Lim, Jaesoo; Kim, Ju-Yong

    2016-04-01

    Darhad basin is located in the northern Mongolia, in the western end of the Baikal Rift Zone. In contrast to the neighboring Lake Hovsgol, Mongolia's largest and deepest lake, the Darhad is a drained lake basin. It is ~100 km long (north-south), 20-40 km wide and covered by sediments which locally exceed 500 m thickness (Zorin et al., 1989). Darhad basin is characterized by alternating episodes of expansion and desiccation that are closely related with the Pleistocene damming events. Previous studies of the Darhad Basin suggest that the last paleolake was dammed by a large glacier or the sediments (Selivanov, 1967, 1968; Krivonogov et al., 2005; Gillespie et al., 2008). Especially, recent expansion of the paleolake might be caused by the two glacial maxima during MIS 4 and 2. However, glacier-dammed lakes might be short-lived, dried up and permafrost occurred in the drained basin during the Holocene period. The uppermost paleolake sediments (13.2 m depth) are exposed following the curvature of the meandering river (called "Hodon outcrop"). It is considered the most likely site for the youngest paleolake sediments because it is distributed in the northern middle part of the paleolake. Krivonogov et al. 2012 described the Hodon outcrop with the sedimentological and chronological data. Age dating of 16 samples (11 mollusk shells, 5 wood fragments) indicated that Hodon outcrop sediments were deposited between 10.1±7 and 4.9±5 ka. However, the ages obtained on shells much older dates than the matched wood samples because of ingestion of old carbon by mollusks. The age difference between shells and wood fragments is a minimum of 1.73 ka and a maximum of 3.41 ka (average 2.5 ka). In this case, 14C ages from shells should be corrected with appropriate correction factor. However, the old carbon effects could vary temperally and spatially in the Darhad paleolake. The limited number of the 14C ages from wood fragments result in a simple linear trend in the depth-age curve

  10. Northern European adolescent attitudes toward dating violence.

    Science.gov (United States)

    Bowen, Erica; Holdsworth, Emma; Leen, Eline; Sorbring, Emma; Helsing, Bo; Jaans, Sebastian; Awouters, Valère

    2013-01-01

    A focus group methodology was used to examine attitudes toward dating violence among 86 adolescents (aged 12-17) from four northern European countries (England, Sweden, Germany, and Belgium). Four superordinate themes were identified from thematic analyses: gender identities, television as the educator, perceived acceptability of dating violence, and the decision to seek help/tell someone. Although violence in relationships was generally not condoned, when violence was used by females, was unintended (despite its consequences), or was in retaliation for infidelity, violence was perceived as acceptable. Adolescents indicated that their views were stereotypical and based solely on stereotypical television portrayals of violence in relationships. Stereotypical beliefs and portrayals generate barriers for victimized males to seek help because of fear of embarrassment. PMID:24047043

  11. Radiocarbon dating development and practices at MINT

    International Nuclear Information System (INIS)

    The MINT radiocarbon dating technique was introduced and a very well-designed vacuum line was developed to generate benzene from samples containing carbon. A liquid scintillation counter provides a very good prerequisite for precise measurement of the C-14 activity in the benzene. From time to time, assessment on the status of the analytical capabilities of the system and advice on improvement and upgrading required was made. For routine analysis, standard sampling, pretreatment, carbon dioxide conversion and measurement procedures were adopted. Radiocarbon dating is now, one of the most important developments of the twenties century in the comprehension of the history of human development, a quick, easy, reliable and scientifically acceptable method to determine the age of historical artefacts and archaeological samples. (Author)

  12. Dating cremated bone: the scientific background

    Directory of Open Access Journals (Sweden)

    Lanting, J. N.

    1999-12-01

    Full Text Available A new method of obtaining absolute chronology dates out of burnt or cremated bone is presented. The authors explain their recent experiments and give promising results.

    Los autores presentan un nuevo método para obtener fechas de datación absoluta a partir de restos de hueso sometidos a diferentes grados de combustión y explican algunas de sus recientes experiencias y los resultados obtenidos.

  13. Progress and problems with automated TL dating

    International Nuclear Information System (INIS)

    A number of basic problems connected with the measurement of beta and gamma dose-rates are discussed, and the possibility of using low-temperature peaks in quartz and feldspar for dose-rate measurements is examined. Preliminary results of TL measurements on individual grains of quartz and feldspar are presented. A TL dating method based on the difference in the archaeological dose received by potassium feldspar and quartz grains is proposed. (author)

  14. 14C AMS dating Yongcheon cave

    International Nuclear Information System (INIS)

    The biggest island in South Korea is Jeju Island, which lies 80 km south of the mainland and has one shield volcano, Mt. Halla. The volcanic island and its lava tubes were added to the world heritage list by UNESCO in 2007. Among the many lava tubes on the island, a unique cave had been accidentally found in 2005 while some workers were replacing a telephone pole. Until the discovery, it had been completely isolated from the outside by naturally-built sand blocks. Yongcheon cave is a lime-decorated lava tube showing both the properties of a volcanic lava tube and a limestone cave. This cave, about 3 km in length, is acknowledged to be the best of this type in the world and includes a large clean-water lake, lava falls, and richly developed speleothems inside it. Even though there is archaeological evidence from well preserved pottery that ancient people entered this place, the preservation of artifacts was ensured by a geological change that made later entrance difficult. We have collected charcoal samples scattered around the cave and dated them using AMS. Ages were in the range of ca. 1570-1260 BP (A.D. 340–880) and this corresponds to the Ancient Three Kingdoms and the Unified Silla era in Korean history. The 14C AMS measurement results presented in this paper on wood charcoal provide precise dates which will be very useful not only to clarify the nature of human activities in this cave but also to provide reference dates when comparing other dating methods.

  15. {sup 14}C AMS dating Yongcheon cave

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.H., E-mail: jefflee@snu.ac.kr [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Choe, K. [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, J.C. [Dept. of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Choi, S.H.; Kang, J.; Song, S.; Song, Y.M. [AMS Lab., NCIRF, Seoul National University, Seoul 151-742 (Korea, Republic of); Jang, J.G. [Jeju National Museum, Jeju 690-782 (Korea, Republic of)

    2013-01-15

    The biggest island in South Korea is Jeju Island, which lies 80 km south of the mainland and has one shield volcano, Mt. Halla. The volcanic island and its lava tubes were added to the world heritage list by UNESCO in 2007. Among the many lava tubes on the island, a unique cave had been accidentally found in 2005 while some workers were replacing a telephone pole. Until the discovery, it had been completely isolated from the outside by naturally-built sand blocks. Yongcheon cave is a lime-decorated lava tube showing both the properties of a volcanic lava tube and a limestone cave. This cave, about 3 km in length, is acknowledged to be the best of this type in the world and includes a large clean-water lake, lava falls, and richly developed speleothems inside it. Even though there is archaeological evidence from well preserved pottery that ancient people entered this place, the preservation of artifacts was ensured by a geological change that made later entrance difficult. We have collected charcoal samples scattered around the cave and dated them using AMS. Ages were in the range of ca. 1570-1260 BP (A.D. 340-880) and this corresponds to the Ancient Three Kingdoms and the Unified Silla era in Korean history. The {sup 14}C AMS measurement results presented in this paper on wood charcoal provide precise dates which will be very useful not only to clarify the nature of human activities in this cave but also to provide reference dates when comparing other dating methods.

  16. Dating of glaciers by lead-210

    International Nuclear Information System (INIS)

    A method is described of dating neve and ice, based on the radioactive decay of 210Pb or RaD (T1/2 = 22 yr). Two techniques have been developed to measure the very low activities of 210Pb (0.1 to 5 dpm). One uses a semi-conductor detector to take spectral measurements of the α-activity of 210Po labelled with 208Po; the other is based on measurement of the β-radiation of 210Bi by a proportional counter. The method has been applied to several sections of neve taken in the Antarctic, in Greenland and on an alpine glacier, each covering a period of more than 100 yr. The results show that in the Polar regions the neve behaves as a closed system from the moment of precipitation, the 210Pb dating this moment. The accumulation rates deduced from the 210Pb distribution as a function of depth are in excellent agreement with those of other methods. In temperate glaciers, because of the homogenization of the neve caused by percolation of the melting water, the event dated by the 210Pb is the transformation of the neve into compact ice. The 210Pb ages obtained with ice samples from the ablation area of the Kesselwandferner (Austrian Tyrol) are in good agreement with current ideas on glacier dynamics. Comparison of the 210Pb and fission product concentrations has revealed no evidence of the artificial production of 210Pb by the explosion of nuclear devices. With samples of 2 kg, this method can be used to date ice with an age of 100 yr in the Antarctic and more than 120 yr in Greenland and in temperate zones. (author)

  17. Carbon-14 Bomb-Pulse Dating

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, B A

    2007-12-16

    Atmospheric testing of nuclear weapons during the 1950s and early 1960s doubled the concentration of carbon-14 atmosphere and created a pulse that labeled everything alive in the past 50 years as carbon moved up the food chain. The variation in carbon-14 concentration in time is well-documented and can be used to chronologically date all biological materials since the mid-1950s.

  18. Thermoluminescence Dating of Early Ceramics from Oman

    OpenAIRE

    Wagner, Günther; Yule, Paul

    2007-01-01

    Thermoluminescence (TL) measurements at Samad al-Shan and al-Maysar were conducted in 1981 and evaluated at the Max Planck Institute for physics in Heidelberg. Unfortunately, these were never published. Since the time TL-measurements were made, the typology of slags and our knowledge of the different sites have advanced considerably for all of the periods. TL itself has been subject to considerable study since samples were taken in Oman in 1981. The new datings support other categories of evi...

  19. Improved heaters for a thermoluminescence dating equipment

    International Nuclear Information System (INIS)

    The improvement of the heater system used in a thermoluminescence dating apparatus is reported. Two variants of heater, planchet system and block system are presented. Made of a cheap material as graphite the heaters are very simple constructively, ensure minimal heat losses and a good linearity of the temperature rising under low power requirements. To minimized heat lass and to ensure maximum temperature uniformity over heated aria we have used cryogenic principals. (authors)

  20. ESR dating at Mezmaiskaya Cave, Russia

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, A.R. [Department of Chemistry, Williams College, Williamstown, MA, 01267 (United States)]. E-mail: anne.r.skinner@williams.edu; Blackwell, B.A.B. [Department of Chemistry, Williams College, Williamstown, MA, 01267 (United States); Martin, Sara [Department of Chemistry, Williams College, Williamstown, MA, 01267 (United States); Ortega, A. [RFK Science Research Institute, Flushing, NY, 11366 (United States); Blickstein, J.I.B. [RFK Science Research Institute, Flushing, NY, 11366 (United States); Golovanova, L.V. [Laboratory of Prehistory, St. Petersburg (Russian Federation); Doronichev, V.B. [Laboratory of Prehistory, St. Petersburg (Russian Federation)

    2005-02-01

    Mezmaiskaya Cave has yielded more than 10,000 artifacts, thousands of very well preserved faunal remains, and hominin remains, found in seven Middle Paleolithic (Mousterian) and three Upper Paleolithic levels. A complete Neanderthal infant skeleton was preserved in anatomical juxtaposition lying on a large limestone block, overlain by the earliest Mousterian layer, Layer 3. Twenty-four skull fragments from a 1-2 year-old Neanderthal infant, showing post-mortem deformation, occurred in a pit originating in the Mousterian Layer 2 and penetrating into underlying layers 2A and 2B(1). Bone from Layer 2A was dated by AMS {sup 14}C at 35.8-36.3{+-}0.5 kyr BP. Direct dating of Neanderthal bone from Layer 3 gave an age of 29 kyr, but that is now considered to be due to contamination by modern carbon. Fourteen large mammal teeth from Layers 2 through 3 have been dated by standard electron spin resonance (ESR). Low U concentrations in both the enamel and dentine ensure that ESR ages do not depend significantly on the U uptake model, but do depend strongly on the sedimentary dose rates. Assuming a sedimentary water concentration equal to 20 wt%, ESR ages for the Mousterian layers range from 36.2 to 73.0{+-}5.0 ka.

  1. Progress in ESR dating of fossils

    International Nuclear Information System (INIS)

    In this review the progress of ESR dating is briefly described together with its historical development. Examples of fossil dating include shells and corals in geological sediments, fossil bones and teeth in anthropology and fossil woods in geology. The total dose of natural radiation (TD) equivalent to the archaeological dose in TL dating was obtained by the additive dose method. Initially, the TDs were plotted against the known ages; using the apparent annual dose-rate thus obtained gives the ESR age within a factor of 2 or 3 for a fossil. Precise assessment of the radiation environment was made later taking the disequilibrium of uranium series disintegration into account. ESR ages of corals agreed well with those obtained by radiocarbon and uranium-thorium methods. The time-independent accumulation rate or a linear accumulation or uranium was adopted as a first sensible model for the opensystem fossil bones: the relation between the TD and the age explains the ages of anthropologically important bones. Lastly, geological assessment of fossil woods was made by ESR based on the organic radicals and electron traps in the silicified part. (author)

  2. Low energy cyclotron for radiocarbon dating

    International Nuclear Information System (INIS)

    The measurement of naturally occurring radioisotopes whose half lives are less than a few hundred million years but more than a few years provides information about the temporal behavior of geologic and climatic processes, the temporal history of meteoritic bodies as well as the production mechanisms of these radioisotopes. A new extremely sensitive technique for measuring these radioisotopes at tandem Van de Graaff and cyclotron facilities has been very successful though the high cost and limited availability have been discouraging. We have built and tested a low energy cyclotron for radiocarbon dating similar in size to a conventional mass spectrometer. These tests clearly show that with the addition of a conventional ion source, the low energy cyclotron can perform the extremely high sensitivity 14C measurements that are now done at accelerator facilities. We found that no significant background is present when the cyclotron is tuned to accelerate 14C negative ions and the transmission efficiency is adequate to perform radiocarbon dating on milligram samples of carbon. The internal ion source used did not produce sufficient current to detect 14C directly at modern concentrations. We show how a conventional carbon negative ion source, located outside the cyclotron magnet, would produce sufficient beam and provide for quick sampling to make radiocarbon dating milligram samples with a modest laboratory instrument feasible

  3. Low energy cyclotron for radiocarbon dating

    Energy Technology Data Exchange (ETDEWEB)

    Welch, J.J.

    1984-12-01

    The measurement of naturally occurring radioisotopes whose half lives are less than a few hundred million years but more than a few years provides information about the temporal behavior of geologic and climatic processes, the temporal history of meteoritic bodies as well as the production mechanisms of these radioisotopes. A new extremely sensitive technique for measuring these radioisotopes at tandem Van de Graaff and cyclotron facilities has been very successful though the high cost and limited availability have been discouraging. We have built and tested a low energy cyclotron for radiocarbon dating similar in size to a conventional mass spectrometer. These tests clearly show that with the addition of a conventional ion source, the low energy cyclotron can perform the extremely high sensitivity /sup 14/C measurements that are now done at accelerator facilities. We found that no significant background is present when the cyclotron is tuned to accelerate /sup 14/C negative ions and the transmission efficiency is adequate to perform radiocarbon dating on milligram samples of carbon. The internal ion source used did not produce sufficient current to detect /sup 14/C directly at modern concentrations. We show how a conventional carbon negative ion source, located outside the cyclotron magnet, would produce sufficient beam and provide for quick sampling to make radiocarbon dating milligram samples with a modest laboratory instrument feasible.

  4. Carbonates in leaching reactions in context of 14C dating

    Science.gov (United States)

    Michalska, Danuta; Czernik, Justyna

    2015-10-01

    Lime mortars as a mixture of binder and aggregate may contain carbon of various origins. If the mortars are made of totally burnt lime, radiocarbon dating of binder yields the real age of building construction. The presence of carbonaceous aggregate has a significant influence on the 14C measurements results and depending on the type of aggregate and fraction they may cause overaging. Another problem, especially in case of hydraulic mortars that continue to be chemically active for a very long time, is the recrystallization usually connected with rejuvenation of the results but also, depending on local geological structures, with so called reservoir effect yielding apparent ages. An attempt in separating the binder from other carbonaceous components successfully was made for samples from Israel by Nawrocka-Michalska et al. (2007). The same preparation procedure, after taking into account the petrographic composition, was used for samples coming from Poland, Nawrocka et al. (2009). To verify the procedure used previously for non-hydraulic samples determination an experimental tests on carbonaceous mortars with crushed bricks from Novae in Bulgaria were made. Additionally, to identify different carbonaceous structures and their morphology, a cathodoluminescence and scanning electron microscope with electron dispersive spectrometer were applied. The crushed bricks and brick dust used in mortars production process have been interpreted as an alternative use to other pozzolanic materials. The reaction between lime and pozzolanic additives take place easily and affects the rate and course of carbonates decomposition in orthophosphric acid, during the samples pretreatment for dating. The composition of the Bulgarian samples together with influence of climate conditions on mortar carbonates do not allow for making straightforward conclusions in chronology context, but gives some new guidelines in terms of hydraulic mortars application for dating. This work has mainly

  5. Chemical networks

    Science.gov (United States)

    Thi, Wing-Fai

    2015-09-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One on-going research subject is finding new paths to synthesize species either in the gas-phase or on grain surfaces. Specific formation routes for water or carbon monoxide are discussed in more details. 13th Lecture of the Summer School "Protoplanetary Disks: Theory and Modelling Meet Observations"

  6. Date-rape drugs scene in Poland.

    Science.gov (United States)

    Adamowicz, Piotr; Kała, Maria

    2005-01-01

    Since the beginnings of twenty-first century in Poland increasing number of reports about the drug-facilitated sexual assaults have been observed. Many drugs have been identified as so-called "date-rape drugs", because of their pharmacological properties, especially inducing amnesia. These drugs are used for the purpose of "drugging" unsuspected victims and than raping them. In a typical scenario, the perpetrator surreptitiously adds "date-rape drug" to the alcoholic or non-alcoholic beverage of an unsuspecting person, who is subsequently sexually assaulted while under the influence of this substance. Many victims do not report the incident until several days after the event or even do not report it at all. They report the incident so late after the events because they often have problems with remember the course of incident. It causes that victim is not reliable witness for justice. Detection of "date-rape drugs" in biological fluids is unequivocal evidence of perpetration. Analysis of biological fluids collected from victims of rapes for presence of drugs was rare in Poland up to now. The aim of this study is to show the use of "date-rape drugs" in Poland. Materials for this study were from the routine casework elaborated at the Institute of Forensic Research in Kraków. APCI-LC-MS methods were applied for screening of biological fluids (blood and/or urine) for amphetamine and its 6 analogues, for 12 substances from benzodiazepine group and for quantification of the detected drugs. HPLC-DAD was used as a screening method for wide range of medicinal drugs, and NCI-GC-MS methods for determination of ketamine and tetrahydrocannabinols (delta9-tetrahydrocannabinol, 9THC) and its metabolite (11-nor-carboxy-delta9-tetrahydrocannabinol, THCCOOH). In 2000-2004, the biological fluids taken from 33 persons, both sexually assaulted or perpetrators were analysed. In 2000 and 2002 not any case of this type was registered, in 2001 only two cases were recorded. After 2003

  7. Casual dating online: sexual norms and practices on French heterosexual dating sites

    OpenAIRE

    Bergström, Marie

    2011-01-01

    "Während über das Internet vermittelte gelegentliche Treffen zwischen homosexuellen Männern bereits ein etablierter Forschungsgegenstand in den Sozialwissenschaften sind, ist die Forschung zu heterosexuellem Online-Dating größtenteils auf die Suche nach romantischen Langzeitbeziehungen fokussiert. Der vorliegende Artikel will damit beginnen, diese Forschungslücke zu füllen, indem er den möglichen neuen sexuellen Bereich untersucht, der durch heterosexuelle Online-Dating-Plattformen entsteht. ...

  8. Isotopic signature of Madeira basaltic magmatism

    International Nuclear Information System (INIS)

    Chemical composition of the basalts of Madeira Island is studied. To assess the isotopic sources of magmatism the Pb-Sr, Sm-Nd, U-Th-Pb systems were investigated in a number of basalts. It is shown that the island's rocks are characterized by the mostly deplet sources in relation to Pb-Sr and Sm-Nd systems (87Sr/86Sr - 0.70282-0.70292, 143Nd/144Nd - 0.52303-0.51314). Isotopic composition of lead testifies that the magmatism reservoir is some enriched. It is concluded that the magmatism of Madeira Island is a new example of world ocean island's volcanism

  9. 7 CFR 35.8 - Date of export.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Date of export. 35.8 Section 35.8 Agriculture... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS EXPORT GRAPES AND PLUMS Definitions § 35.8 Date of export. Date of export means the date of loading on board...

  10. Improvement of date palm by radiation and growth requlators

    International Nuclear Information System (INIS)

    The efficiency of date palm breeding could be improved by changing the sex of date palm flowers, the identification of sexes at early stage and the induction of a sexual embryo in date palm. Date palm breeder wishes to find out source of apomixis because of its application

  11. 7 CFR 987.157 - Approved date product manufacturers.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Approved date product manufacturers. 987.157 Section... DATES PRODUCED OR PACKED IN RIVERSIDE COUNTY, CALIFORNIA Administrative Rules Qualification to Regulation § 987.157 Approved date product manufacturers. Any person, including date handlers,...

  12. 46 CFR 176.310 - Certification Expiration Date Stickers.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Certification Expiration Date Stickers. 176.310 Section... Letters § 176.310 Certification Expiration Date Stickers. (a) A Certification Expiration Date Sticker... operated without a valid Certification Expiration Date Sticker affixed to the vessel on a place that is:...

  13. 21 CFR 201.17 - Drugs; location of expiration date.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Drugs; location of expiration date. 201.17 Section...) DRUGS: GENERAL LABELING General Labeling Provisions § 201.17 Drugs; location of expiration date. When an expiration date of a drug is required, e.g., expiration dating of drug products required by § 211.137 of...

  14. 46 CFR 160.066-10 - Expiration date.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Expiration date. 160.066-10 Section 160.066-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) EQUIPMENT, CONSTRUCTION, AND MATERIALS....066-10 Expiration date. Each approved signal must have an expiration date marked on it. That date...

  15. 42 CFR 431.108 - Effective date of provider agreements.

    Science.gov (United States)

    2010-10-01

    ... perform. (b) All requirements are met on the date of survey. The agreement is effective on the date the... 42 Public Health 4 2010-10-01 2010-10-01 false Effective date of provider agreements. 431.108... Administrative Requirements: Provider Relations § 431.108 Effective date of provider agreements....

  16. Chemical cleaning, decontamination and corrosion

    International Nuclear Information System (INIS)

    Chemical cleaning of process equipments and pipings in chemical/petrochemical industries is necessitated for improving operation, for preventing premature failures and for avoiding contamination. In developing a chemical formulation for cleaning equipments, the important aspects to be considered include (i) effective removal of corrosion products and scales, (ii) minimum corrosion of the base metal, (iii) easy to handle chemicals and (iv) economic viability. As on date, a wide variety of chemical formulations are available, many of them are either proprietory or patented. For evolving an effective formulation, knowledge of the oxides of various metals and alloys on the one hand and acid concentration, complexing agents and inhibitors to be incorporated on the other, is quite essential. Organic acids like citric acid, acetic acid and formic acid are more popular ones, often used with EDTA for effective removal of corrosion products from ferrous components. The report enumerates some of the concepts in developing effective formulations for chemical cleaning of carbon steel components and further, makes an attempt to suggest simple formulations to be developed for chemical decontamination. (author). 6 refs., 3 fi gs., 4 tabs

  17. Chemical pressure

    OpenAIRE

    Hauser, Andreas; Amstutz, Nahid; Delahaye, Sandra; Sadki, Asmaâ; Schenker, Sabine; Sieber, Regula; Zerara, Mohamed

    2002-01-01

    The physical and photophysical properties of three classic transition metal complexes, namely [Fe(bpy)3]2+, [Ru(bpy)3]2+, and [Co(bpy)3]2+, can be tuned by doping them into a variety of inert crystalline host lattices. The underlying guest-host interactions are discussed in terms of a chemical pressure.

  18. Chemical Peels

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ... Chemical peels public SPOT Skin Cancer™ Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ...

  19. Chemical Mahjong

    Science.gov (United States)

    Cossairt, Travis J.; Grubbs, W. Tandy

    2011-01-01

    An open-access, Web-based mnemonic game is described whereby introductory chemistry knowledge is tested using mahjong solitaire game play. Several tile sets and board layouts are included that are themed upon different chemical topics. Introductory tile sets can be selected that prompt the player to match element names to symbols and metric…

  20. Chemical dispersants

    NARCIS (Netherlands)

    Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.

    2016-01-01

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil biodeg

  1. Characterization, analysis and dating of archaeological ceramics from the Amazon basin through nuclear techniques

    International Nuclear Information System (INIS)

    The aim of this work is to contribute to the research in the reconstruction of part of the pre-history of the Amazon Basin by means of an analytical methods combined with multivariate analysis, given a analytic basis that can be continued by the archaeological work, through the identification, classification, provenance and dating the ceramics found in different archaeological sites of the Hydro graphic Basin of the Purus river. Neutron activation analysis in conjunction multivariate statistical methods were used for the identification and classification and thermoluminescence was used for the dating. Chemical composition results were in better agreement with archaeological classification for the archaeologically define Iquiri, Quinan and Xapuri phases and less characteristics the Iaco and Jacuru archaeological phase were not well characterized. An homogeneous group was established by most of the samples collected from the Los Angeles Archaeological Site (LA) and was distinct from all the other groups analysed. The provenance studies made with ceramics collected at this site shows that they were made with clay from nearby river (Rio Ina). From the LA ceramics dating the average date of site occupation was 1660 years. The ceramic dating results from the external wall of a circular earth wall construction confirm the relation with the local pre-history. Beyond the Acre material two urns were dated from the Archaeological Site Morro Grande and Sao Jose at Araruama, Rio de Janeiro. (author)

  2. Direct dating of hominids using ESR and U-series dating

    Energy Technology Data Exchange (ETDEWEB)

    Gruen, R. [Australian National University, Canberra, ACT (Australia). Research School of Earth Science

    1999-11-01

    Full text: Dating studies on palaeoanthropological sites is usually carried out on material associated with the human remains, such as the sediment, charcoal or other fauna rather than the human specimen itself. The reason lies in the fact that most dating techniques are destructive and because the hominid remains are too rare to be sacrificed for dating. This indirect dating approach is in many cases not satisfactory, because:(i) the human remains are often buried into the sediments and the association with other materials is uncertain (e.g. Skhul, Qafzeh, etc.);(ii) faunal remains or minerals from the sediment are re-worked from older deposits (see e.g. present discussion of the age of the Homo erectus remains in Indonesia);(iii) the hominid specimen was discovered at a time when no careful excavations were carried out and it is impossible to correlate the specimen with other datable material (nearly 90% of all palaeoanthropological specimen). For example, the hominid burial site of Qafzeh in Israel has been dated by several independent dating laboratories with a multitude of methods. However, the data are still not accepted by some because the dating has not been carried out on the hominid specimen. Until recently, hominid fossils could only be dated by radiocarbon. This method reaches back to about 40,000 years. As a consequence, all the older fossils could not be analysed and many important questions in our understanding of human evolution could not be addressed. Human remains are scarce and extremely valuable, therefore any sort of destruction has to be kept to an absolute minimum. This is of particular importance in Australia where any human fossils are sacred. Thus, for the analysis of hominid material it was necessary to develop a more or less non-destructive techniques. This has been accomplished in recent years by the application of ESR dating of tooth enamel and a combination of gamma spectrometric and TIMS U-series dating of bones. The examples of

  3. Using thermoluminescence (TL) in ceramics dating

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) dating is a radiometric method based on the fact that trace amounts of radioactive atoms, such as uranium and thorium produce constant low doses of background ionizing radiation in rock, soil and clay. The atoms of crystalline solids, such as pottery and rock, can be altered by this radiation. Specifically, the electrons of quartz, feldspar, diamond or calcite crystals could be displaced from their normal positions in atoms and trapped in defects in crystal lattice of the clay. These electrons progressively accumulate over time. When a sample is heated to high temperatures the trapped electrons are released and return to their normal positions in their atoms. This causes them to give off their stored energy in the form of light impulses (photons). This light is referred to as thermoluminescence. A similar effect can be obtained by stimulating the sample with infrared light. The intensity of thermoluminescence is directly related to the amount of accumulated changes produced by background radiation, which, in turn, varies with the age of the sample and the amount of trace radioactive elements it contains. What is actually determined is the amount of elapsed time since the sample had previously been exposed to high temperatures. In the case of a pottery vessel, usually it is the time since it was fired. For the clay or rock lining of a hearth or oven, it is the time since the last intense fire burned there. The effective time range for TL dating is now about 300,000 years down to a few decades. Theoretically, this technique could date samples as old as the solar system. In our work we will present some preliminary results concerning samples and device (Harshaw-2000) preparation for thermoluminescence of feldspar separated from ceramic samples with a well known age. For external doses TLD-100 with high sensitivity (LiF-Mg-Cu-P) was used . (author)

  4. Thermoluminescence dating of some Hungarian medieval churches

    International Nuclear Information System (INIS)

    Thermoluminescence dating of three Hungarian historic churches was performed using the quarz inclusion technique and sup(60)Co gamma irradiation. Quarz grains obtained from the bricks were irradiated and the radiation doses were measured by CaSOsub(4):Dy TL dosemeters. Glow curves of irradiated and non-irradiated samples were also measured. From the results it was concluded that the ages of two churches were 10 and 30 percent less, respectively, than the ages estimated earlier. The age of the third church proved to be correct. (R.P.)

  5. Unperceived dating violence among Mexican students

    OpenAIRE

    María de Lourdes Cortés Ayala; Carolina Bringas Molleda; Luis Rodríguez-Franco; Mirta Flores Galaz; Tamara Ramiro-Sánchez; Francisco J. Rodríguez Díaz

    2014-01-01

    The aim of this ex post facto study was to determine the level of self-perceived abuse and the feelings of fear and entrapment that exist among Mexican students in a dating relationship. We intended to explore possible differences in the prevalence of the various types of violence or victimization between individuals who perceive themselves as being abused and those who do not, combining such perceptions with the feelings of fear and entrapment. The sample was composed of 3,495 Mexican studen...

  6. Radiometric dating of rocks. Chapter 18

    International Nuclear Information System (INIS)

    The study of the abundances and variations in the isotopes of several elements both stable and unstable has become an indispensable approach in earth sciences that helps in understanding the problems related to the age of the rocks and minerals, petrogenesis of a suite of rocks, provenance studies and others. In this article, some commonly used dating methods have been discussed with emphasis on their applications, experimental techniques and instrumentation. Zircon chronology which has now developed as a specialized branch of geochronology is discussed

  7. Water dating in groundwater resources management

    International Nuclear Information System (INIS)

    It is widely accepted that groundwater dating by tritium or radiocarbon can give valuable data on the groundwater age and, as a consequence, can provide information on the age structure and dynamics of the groundwater bodies. The question is: can they and to what extend can they give us a key to decide on the future dynamics on the man-impacted groundwater bodies? The three examples presented below attempt to demonstrate that the benefits and results can be gained from its use do not so much depend on the tool itself but on the art of using that tool

  8. Palm Date Fibers: Analysis and Enzymatic Hydrolysis

    OpenAIRE

    Taherzadeh, Mohammad J.; Keikhosro Karimi; Marzieh Shafiei

    2010-01-01

    Waste palm dates were subjected to analysis for composition and enzymatic hydrolysis of their flesh fibers. The fruit contained 32% glucose and 30% fructose, while the water-insoluble fibers of its flesh consisted of 49.9% lignin and 20.9% polysaccharides. Water-insoluble fibers were settled to 55% of its initial volume in 12 h. The presence of skin and flesh colloidal fibers results in high viscosity and clogging problems during industrial processes. The settling velocity of the fibers was i...

  9. Uses of radiocarbon dating in archaeology

    International Nuclear Information System (INIS)

    Carbon dating is one of the mist effective tools in the archaeologist's kit. It has provided illumination where none was once thought possible. The historians of one hundred years ago could only dream of such a wonderful, albeit frightening atomic clock ticking away, helping to mark the passing of the years and the ages of man. It is a vital part in the investigation and preservation of our past and a lovely bit of analysis to compliment digital records of monuments. It places the plants, animals, and people of yore into an understandable and verifiable context

  10. Thermoluminescence dating of dune sands: some refinements

    International Nuclear Information System (INIS)

    Thermoluminescence data on two different grain size fractions 1-8 μm and 90-105 μm are compared with a view toward examining the post-dispositional mobility of the fine grain fraction within a dune matrix. A 'zero age' sample from a dune top yielded a low sediment equivalent dose. The TL dates at Amarpura suggest that the dune building activity at Amarpura in the Rajasthan desert terminated at around 13,000 years B.P. (author)

  11. Dating Norms and Dating Violence among Ninth Graders in Northeast Georgia: Reports from Student Surveys and Focus Groups

    Science.gov (United States)

    Reeves, Patricia M.; Orpinas, Pamela

    2012-01-01

    This mixed-methods study describes the norms supporting male-to-female and female-to-male dating violence in a diverse sample of ninth graders. The quantitative study, based on student surveys (n = 624), compared norms supporting dating violence by sex, race/ethnicity, and dating status, and it examined the relation between dating violence norms…

  12. The Rate of Cyber Dating Abuse among Teens and How It Relates to Other Forms of Teen Dating Violence

    Science.gov (United States)

    Zweig, Janine M.; Dank, Meredith; Yahner, Jennifer; Lachman, Pamela

    2013-01-01

    To date, little research has documented how teens might misuse technology to harass, control, and abuse their dating partners. This study examined the extent of cyber dating abuse--abuse via technology and new media--in youth relationships and how it relates to other forms of teen dating violence. A total of 5,647 youth from ten schools in three…

  13. Radiometric dating of ochoan (permian) evaporites, WIPP site, Delaware basin, New Mexico, USA

    International Nuclear Information System (INIS)

    The authors have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant - a US DOE facility) site. They undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization, (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data, and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. They have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites-anhydrites yield 220 +/- 10 Ma, even when some sylvites yield lower K-Ar dates due to loss of 40Ar*. K-Ar dates on leonites and kieserites are also low due to 40Ar* loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 +/- 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 +/- 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, they note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of their geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma. 19 references, 1 figure, 5 tables

  14. Palaeo-poo: date from rat scats

    International Nuclear Information System (INIS)

    AMS dating has allowed a detailed study of the stratigraphy of stick-nest rat (Leporillus spp.) middens. The results of multiple dates on apparently the same layers of the middens show that the taphonomy of the midden is complex. Nevertheless, the information recovered from this source is an exciting addition to understanding arid ecosystems. Information about the local and regional vegetation, possible CO2-induced changes in stomata, distribution of mammals and their predator-prey relations has been recovered from the middens. Palaeoecological information coming from the arid zone has been limited but this source provides a breakthrough in providing direct and detailed ecological information. This helps contextualise the late Holocene increase in arid zone archaeological site visibility. It emphasises the pattern of arid zone mammal losses. It provides important corroborating evidence to other palaeoecological records. It is emphasised that the deposits containing pollen and macrofossils are datable using radiocarbon but there are some serious problems in providing ecological information from stick-nest rat middens

  15. Gamma-thermoluminescence dating (GAMMA-TL)

    International Nuclear Information System (INIS)

    The experimental simplification of the TL dating method is one of the CRIAA Laboratory research fields in physics applied to archaeology. For radiochemical homogeneous systems GAMMA-TL allows a significant simplification for the measurement of the natural dose-rate I while preserving an accuracy as good as the one of classical TL dating within certain limiting circumstances. For instance, in the case of large heated structures determination of I reduces to Isub(γ) on site measurement and to k determination. The annual dose-rate is then given by I = GAMMA(k)Isub (γ) with GAMMA(k) = 12.17 k + 2.72. However, it is necessary to test the hypothesis that radioactivity in the structure is homogeneous. For this purpose high resolution γ spectrometry is used as a routine laboratory technique applied to several similar samples of structure. The comparison between the natural γ-ray criteria for the GAMMA-TL method, since for constant conditions, γ-ray intensities must be identical from one sample to another. We are now investigating structures of known age in order to find within what limits the GAMMA-TL can be used. (author)

  16. Chemical flashlamps

    International Nuclear Information System (INIS)

    The authors have characterized the optical output and Nd:glass pumping performance of large-scale (120-cm-long, 1.2-cm-inner-diam), metal-oxidizer chemical flashlamps supplied to us by G.T.E. Sylvania. The experimental results were obtained on the same test bed that was used to study xenon electrical flashlamps, as described in Dependence of Flashlamp Performance on Gas Fill and Bore Size, earlier in this section. The peak Nd inversion levels produced by the chemical lamps were less than or equal to 10% of those generated by a xenon lamp of similar size and energy loading. The Peak Nd levels are in good agreement with predictions for the pumping rates in Nd:glass by a blackbody at the color temperatures of 30000 to 50000C, which they have measured during the burn of the pyrotechnic lamp

  17. 14C dating with the bomb peak: An application to forensic medicine

    International Nuclear Information System (INIS)

    Samples originating from the time period after 1950 can be radiocarbon dated utilising the 14C bomb peak as a calibration curve. The applicability of 'radiocarbon dating' of recent organic human material for the determination of the time of death of humans was tested. The radiocarbon results from hair and lipid samples from individuals with known date of death were compared with the results from two individuals with unknown time of death. An estimate of the year of death for the unknowns could be derived by this way. Due to the long turnover time of collagen in human bones it is not possible to use the radiocarbon content of bone collagen for a reliable estimate. In order to study the time dependence of the collagen turnover we tested 'soft' chemical methods for the isolation of collagen from the bone matrix. First radiocarbon results of this investigation are presented

  18. Improvement of ternary recycled polymer blend reinforced with date palm fibre

    International Nuclear Information System (INIS)

    Highlights: • Date palm fibre treated with 1% MA improved adhesion and dispersion in the blend. • The improvement in mechanical properties and thermal stability were confirmed. • Fibre addition did not change melting and crystallisation temperature of the blends. - Abstract: This paper investigates the study and preparation of date palm fibre reinforced recycled polymer blend composites. This is the first paper which describes the recycled polymer ternary blends of (1) recycled low density polyethylene (RLDPE), (2) recycled high density polyethylene (RHDPE) and (3) recycled polypropylene (RPP). The date palm fibre reinforced composites (CD00) were prepared by maintaining constant weight% of fibre of 20 wt% without any fibre treatment. Maleic anhydride (MA) was used as the compatabilizer (1 and 2 wt%) and the effect of compatabilizer on the blend matrix composites was studied. The mechanical, thermal, morphological properties, water absorption and chemical resistance properties were evaluated for these composites and also studied for pure blend matrix (C00). Date palm fibre improved the tensile strength and hardness of recycled polymer blend matrix. Further improvement was achieved with 1% MA (CD1), which showed that 1% MA treated composites (CD1) had higher tensile strength, modulus and hardness properties. Thermal stability and water absorption were improved by 1% MA. These improvements were demonstrated at the nanoscale level by the decrease in roughness appearing in Atomic Force Spectroscopic Microscopy analysis indicating that flow is better under this concentration. The SEM analysis also showed that the fibre matrix adhesion improved by adding 1 wt% (CD1) of MA. The melting and crystallisation temperatures of the blends did not change with the addition of date palm fibre and MA, indicating that the additives did not influence the melting and crystallisation properties of the composites. The chemical resistance test results showed that these composites

  19. Drivers of hemispheric differences in return dates of mid-latitude stratospheric ozone to historical levels

    Directory of Open Access Journals (Sweden)

    H. Garny

    2012-12-01

    Full Text Available Chemistry-climate models (CCMs project an earlier return of northern mid-latitude total column ozone to 1980 values compared to the southern mid-latitudes. The chemical and dynamical drivers of this hemispheric difference are investigated in this study. The hemispheric asymmetry in return dates is a robust result across different CCMs and is qualitatively independent of the method used to estimate return dates. However, the differences in dates of return to 1980 levels between the southern and northern mid-latitudes can vary between 0 and 30 yr across the range of CCM projections analyzed. An attribution analysis performed with two CCMs shows that chemically-induced changes in ozone are the major driver of the earlier return of ozone to 1980 levels in northern mid-latitudes; transport changes are of minor importance. This conclusion is supported by the fact that the spread in the simulated hemispheric difference in return dates across an ensemble of twelve models is only weakly related to the spread in the simulated hemispheric asymmetry of trends in the strength of the Brewer–Dobson circulation. The causes for chemically-induced asymmetric ozone trends relevant for the total column ozone return date differences are found to be (i stronger increases in ozone production due to enhanced NOx concentrations in the Northern Hemisphere lowermost stratosphere and troposphere, (ii stronger decreases in the destruction rates of ozone by the NOx cycle in the Northern Hemisphere lower stratosphere linked to effects of dynamics and temperature on NOx concentrations and (iii an increasing efficiency of heterogeneous ozone destruction by Cly in the Southern Hemisphere mid-latitudes as a result of decreasing temperatures.

  20. Dating mortars: three medieval Spanish architectures

    Directory of Open Access Journals (Sweden)

    Quirós Castillo, Juan Antonio

    2011-12-01

    Full Text Available One of the major issues in building archaeology is finding the age of elements and structures discovered. Mortars represent a class of material basically constituted by a mixture of different phases (i.e. binder, aggregates, water and are widely used for constructive uses and artworks. Current scientific literature regarding the possibility of accurate radiocarbon dating for mortars reports different and still contradictory results. In this study, a new protocol for radiocarbon dating of mortar developed at the Centre for Isotopic Research on Cultural and Environmental heritage (CIRCE is used to perform 14C measurements on archaeological mortars coming from three medieval architectures of northern Spain (two churches and the walls of a castle. Results observed will be discussed and compared with independent age estimations (i.e. radiocarbon dating performed on organic materials found in the same study site, archaeological analyses in order to frame experimental observations in the actual site knowledge by means of a multidisciplinary approach.Una de las principales problemáticas a las que se enfrenta la arqueología de la arquitectura es datar los elementos y las estructuras. Las argamasas son un tipo de material constituido por una mezcla de diferentes elementos (agregados, agua y empleadas en muchos tipos de construcciones. Los estudios realizados hasta la actualidad en torno a la posibilidad de realizar dataciones radiocarbónicas precisas han proporcionado resultados contradictorios. El objetivo de este artículo es el de presentar un nuevo protocolo para datar la arquitectura histórica desarrollado por el Centre for Isotopic Research on Cultural and Enviromental Heritage (CIRCE, basado en la realización de dataciones radiocarbónicas de argamasas a partir del análisis de tres arquitecturas medievales del norte del España, dos iglesias y la muralla de un castillo. Los resultados obtenidos han sido confrontados y comparados con otros

  1. New dates reignite human evolution debate

    International Nuclear Information System (INIS)

    Australian research into the Asian fossil record is unearthing controversial evidence with implications for the evolution of humans. Dr Jian-xin Zhao and Prof Ken Collerson from the University of Queensland's Department of Earth Sciences have been studying the fossil record in East Asia for clues to the early migration of hominids out of Africa in collaboration with Chinese archaeologists Dr Kai Hu of Nanjing University and Hankui Xu of Nanjing Institute of Palaeontology, Academia Sinica. Together they have been studying the remains of Nanjing Man, the name given to two Homo erectus skulls and the tooth of a third individual discovered in Tangshan Cave 250 km north-west of Shanghai. Dr Zhao and Prof Collerson have now employed more accurate dating techniques and materials, using a mass spectrometer to analyse the amounts of thorium-230 and uranium-234 in a calcite flowstone above the Nanjing Man fossil bed. Unlike fossil teeth, uranium and thorium became locked into the flowstone's crystal lattice when the calcite became crystallised. Because of this, the U-series decay in the calcite reliably records when the calcite crystallised. Taking into account the half-lives of uranium-234 and thorium-230, Dr Zhao and Prof Collerson determined the age of the calcite flowstone to be 577,000 years old (+44,000/-34,000 years). As the flowstone overlies the fossil bed, this date only defines the minimum age of the Nanjing Man fossil bed. For comparison, the dentine and enamel components of one fossil deer tooth collected from the Nanjing Man fossil bed yielded discordant mass spectrometric U-series ages of 388,000 and 130,100 years, respectively. Dr Zhao says that this 'strongly demonstrates the unreliability of fossil teeth as a chronometer'. Other evidence in the sediments surrounding the fossils has been the presence of flora and fauna that are typical of a glacial period. Dr Zhao therefore believes that the skulls could have been deposited during a glacial period

  2. Dating methods enter high-school physics curriculum

    International Nuclear Information System (INIS)

    The new curriculum of physics of the upper forms in French grammar schools includes a part dedicated to ''nuclear transformations''. One of the applications most often considered in manuals is isotopic dating and generally several methods are explained to pupils: carbon 14 dating, potassium-argon dating (used for dating ancient lava layers) and uranium-thorium dating (used for dating corals). The author reviews with a critical eye the content of manuals and laments through concrete examples the lack of exactness and accuracy of some presentations. (A.C.)

  3. Ancestry sampling for Indo-European phylogeny and dates

    OpenAIRE

    Rama, Taraka

    2016-01-01

    The date of the root of the Indo-European language family received much attention due to the application of Bayesian phylogenetic methods since the beginning of the last decade. The inferred root date of the family moved along with the development of new methods and better data. In this paper, I compare two dating techniques known as node-dating and total evidence dating for the Indo-European language family. I find that the total evidence dating based on a birth death tree infers age which i...

  4. Methodology of the carbonates dating by the uranium series unbalance by mass spectrometry

    International Nuclear Information System (INIS)

    There are many dating methods largely used according to the kind of material to be dated. Methods that rely on the time-dependency of geochemical disequilibrium between daughter and parent isotope, from the '238U, 235U and 232Th natural decay system, whose final members are stable Pb isotopes, are the most useful in a broader variety of geological, hydrological and archaeological problems. The use of this method in cave deposits like speleothems and clastic sediments proved to be a powerful tool to study past climatic and environmental changes. Speleothems like stalagmites are frequently used in paleoenvironmental interpretations. This method may be applied to rocks and underground water dating, erosion studies, transport and sedimentation processes, interactions between rock-groundwater, among others. The present work focuses on the chemical preparation of the U-Th method including the chemical procedures to avoid laboratory contamination and the mass spectrometer precise calibration in order to get high reproducibility. The process has many steps: samples preparation; digestion and chromatographic separation using standards and samples already dated in other laboratories; determination of the isotopic ratios by mass spectrometers, and a case study based on a stalagmite from Joao Arruda cave, Bonito, Mato Grosso State, Brazil. The obtained data shows the reliability of the method works, mostly in relation to co precipitation of U and Th and to the chromatographic separation of these metals. It is also observed that the obtained dates are within the errors for each sample and are very similar to the dates obtained in other laboratories (validated to this methodology). Further improvements are necessary to achieve better results, mostly related to the reading method in the MC-ICP-MS. The case study in the JA-5 stalagmite shows that it stopped growing around 2,0 ky. This is a different result from that obtained on JA-3 stalagmite, from the same cave, but placed in a

  5. K/Ar dating of diagenetic illite

    International Nuclear Information System (INIS)

    Ascertaining the potassium/argon (K/Ar) age of diagenetic illite yields important information for hydrocarbon exploration since the growth of this mineral in the pores of sandstone reservoir and oil migration are inter linked events in the diagenetic evolution of rocks. Illite was mechanically separated by repeating a series of ultrasonic baths and ultrasonic probes followed by high-speed centrifuging. Resultant fractions were analyzed by X-ray diffractometry to measure the illite content of each sample. The separated illite material was found to be composed of illite and ordered mixed layer illite-smectite with 80% illite layers. Separated fractions were dated radiometrically by the K/Ar method. Preliminary results indicate an average age of some 200 m.y., which marks the end of the diagenetic development of the illite of this area. (author)

  6. Application of krypton-85 in groundwater dating

    International Nuclear Information System (INIS)

    The method for determination 85Kr activity in groundwater and its application in isotope hydrology is presented. Various aspects of 85Kr presence in the earth's ecosphere are discussed in the first part of the paper. The method for 85Kr activity measurement in groundwater is presented in the second part of the paper. Analytical procedure consists of the following steps: extraction of the gases dissolved in water sample, separation of the Ar+Kr mixture from the gases, 85Kr activity measurement in miniature proportional counter, mass spectrometry determination of the krypton gas volume in the proportional counter. About 7 days is necessary for complete analysis of one sample - the error of analysis not exceeds 10 per cent. The results of 85Kr activity measurements (together with tritium and carbon 14C determinations) in 14 different water samples allowed to verify usefulness of 85Kr dating of young water. (author)

  7. Dating human cultural capacity using phylogenetic principles.

    Science.gov (United States)

    Lind, J; Lindenfors, P; Ghirlanda, S; Lidén, K; Enquist, M

    2013-01-01

    Humans have genetically based unique abilities making complex culture possible; an assemblage of traits which we term "cultural capacity". The age of this capacity has for long been subject to controversy. We apply phylogenetic principles to date this capacity, integrating evidence from archaeology, genetics, paleoanthropology, and linguistics. We show that cultural capacity is older than the first split in the modern human lineage, and at least 170,000 years old, based on data on hyoid bone morphology, FOXP2 alleles, agreement between genetic and language trees, fire use, burials, and the early appearance of tools comparable to those of modern hunter-gatherers. We cannot exclude that Neanderthals had cultural capacity some 500,000 years ago. A capacity for complex culture, therefore, must have existed before complex culture itself. It may even originated long before. This seeming paradox is resolved by theoretical models suggesting that cultural evolution is exceedingly slow in its initial stages. PMID:23648831

  8. Radiocarbon dating in groundwater systems. Chapter 4

    International Nuclear Information System (INIS)

    The radioactive isotope of carbon, radiocarbon (14C), was first produced artificially in 1940 by Martin Kamen and Sam Ruben, who bombarded graphite in a cyclotron at the Radiation Laboratory at Berkeley, CA, in an attempt to produce a radioactive isotope of carbon that could be used as a tracer in biological systems (Kamen (1963) [101]; Ruben and Kamen (1941) [102]). Carbon-14 of cosmogenic origin was discovered in atmospheric CO2 in 1946 by Willard F. Libby, who determined a half-life of 5568 a. Libby and his co-workers (anderson et al. (1947) [103]; Libby et al. (1949) [104]) developed radiocarbon dating of organic carbon of biological origin, which revolutionized research in a number of fields, including archaeology and quaternary geology/climatology, by establishing ages and chronologies of events that have occurred over the past approximately 45 ka.

  9. Applicability of 32Si for groundwater dating

    International Nuclear Information System (INIS)

    The paper deals with the results of a study carried out to assess the applicability of 32Si for groundwater dating. Measurements of 32Si in soil samples of the unsaturated zone, of drainage waters and plant material provide the basis for estimating the 32Si initial concentration in groundwater. Different aquifers with groundwater of young and moderate ages have been selected for groundwater studies. For comparison purposes, tritium was found to be a suitable reference isotope. A quantitative interpretation of the 32Si data is generally complicated by geochemical processes, above all in the unsaturated zone. Favourable conditions concerning the use of 32Si in hydrogeology seem to exist in phreatic sand, in limestone and, depending on the thickness and composition of the unsaturated zone, in sandstone aquifers. Further improvement of the 32Si method requires deeper knowledge of the geochemical processes affecting this isotope

  10. Mercury in dated Greenland marine sediments

    DEFF Research Database (Denmark)

    Asmund, G.; Nielsen, S.P.

    2000-01-01

    Twenty marine sediment cores from Greenland were analysed for mercury, and dated by the lead-210 method. In general the cores exhibit a mercury profile with higher mercury concentrations in the upper centimetres of the core. The cores were studied by linear regression of In Hg vs, age of the...... sediment for the youngest 100 years. As a rule the mercury decreased with depth in the sediment with various degrees of significance. The increase of the mercury flux during the last 100 years is roughly a doubling. The increase may be of anthropogenic origin as it is restricted to the last 100 years. In...... four cores the concentration of manganese was found also to increase in the top layers indicating diagenesis. In the other cases the higher concentrations were not accompanied by higher manganese concentrations. The mercury flux to the sediment surface was generally proportional to the Pb-210 flux...

  11. Seasonal dating of Sappho's 'Midnight Poem' revisited

    Science.gov (United States)

    Cuntz, Manfred; Gurdemir, Levent; George, Martin

    2016-04-01

    Sappho was a Greek lyric poet who composed a significant array of pristine poetry. Although much of it has been lost, her reputation has endured thanks to numerous surviving fragments. One of her contributions includes the so-called 'Midnight Poem', which contains a line about the Pleiades, setting sometime before midnight, and supposedly observed from the island of Lesbos. This poem also refers to the setting of the Moon. Sappho's Midnight Poem thus represents a prime example of where ancient poetry and astronomy merge, and it also offers the possibility of seasonal dating. Previously, Herschberg and Mebius (1990) estimated that the poem was composed in late winter/early spring, a time frame that is not unusual for lyrics of an amorous nature. The aim of our paper is to revisit this earlier finding by using modern-day software. Our study confirms Herschberg and Mebius' result, but also conveys further information.

  12. Optically stimulated luminescence dating of rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza

    There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully...... of rock surfaces is successfully tested by application to two different quartz-rich rock types (sandstone and quartzite). Together with the measurement of infrared stimulated luminescence (IRSL) signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can....... Based on the studies of residual luminescence as a function of depth into a rock surface discussed above, a model is developed that relates this increase in residual luminescence to the exposure time. The model is then further developed using the quartz OSL signal from buried quartzite cobbles...

  13. Uranium series dating of Allan Hills ice

    Science.gov (United States)

    Fireman, E. L.

    1986-01-01

    Uranium-238 decay series nuclides dissolved in Antarctic ice samples were measured in areas of both high and low concentrations of volcanic glass shards. Ice from the Allan Hills site (high shard content) had high Ra-226, Th-230 and U-234 activities but similarly low U-238 activities in comparison with Antarctic ice samples without shards. The Ra-226, Th-230 and U-234 excesses were found to be proportional to the shard content, while the U-238 decay series results were consistent with the assumption that alpha decay products recoiled into the ice from the shards. Through this method of uranium series dating, it was learned that the Allen Hills Cul de Sac ice is approximately 325,000 years old.

  14. Role of radiation dating technique - one example

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Shigueo [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Etchevarne, Carlos A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Fac. de Filosofia e Ciencias Humanas. Dept. Antropologia e Etnologia; Cano, Nilo F.; Munita, C.S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-07-01

    Full text: The great majority of archaeological or geological dating technique is based on radiation effect. The so called radioactivity method uses radioactive decays of elements. This is the case of the well known radiocarbon or carbon-14 method. Also the method of relating daughter nucleus to decaying nucleus, as in K-40/Ar-40, Th- 230/U-234, etc. Here we will concentrate in the method based on energy deposition in a solid by radiation from the disintegration of U-series and Th-series. {beta}-rays emitted by the decay of K-40 into Ca-40 (80%) and Ar-40 (11%) also contributes. The role of {alpha}, {beta} and {gamma} radiation emitted by radionuclides in the U-238 and Th-232 series and of {beta} rays from the decay of K-40, all of them in the soil irradiate anything in their course. For dating, we can have sediments as well as potteries produced by ancient people and became buried. The important process consists in transferring a fraction of the energy of radiation to the solid, mainly liberating electrons from valence band to conduction band and from there to traps. In many case the energy of the radiation is used to create defects which in turn create energy levels (traps) in the forbidden gap (or energy gap). There are three ways to recover the energy stored in the solid: (1) by emission of light optically stimulated (OSL), (2) by emission of light thermally stimulated (TL), (3) by microwave absorption (EPR or ESR). Using these techniques among several applications, we will present one to find the first settlers in the northeaster region of Brazil. (author)

  15. Role of radiation dating technique - one example

    International Nuclear Information System (INIS)

    Full text: The great majority of archaeological or geological dating technique is based on radiation effect. The so called radioactivity method uses radioactive decays of elements. This is the case of the well known radiocarbon or carbon-14 method. Also the method of relating daughter nucleus to decaying nucleus, as in K-40/Ar-40, Th- 230/U-234, etc. Here we will concentrate in the method based on energy deposition in a solid by radiation from the disintegration of U-series and Th-series. β-rays emitted by the decay of K-40 into Ca-40 (80%) and Ar-40 (11%) also contributes. The role of α, β and γ radiation emitted by radionuclides in the U-238 and Th-232 series and of β rays from the decay of K-40, all of them in the soil irradiate anything in their course. For dating, we can have sediments as well as potteries produced by ancient people and became buried. The important process consists in transferring a fraction of the energy of radiation to the solid, mainly liberating electrons from valence band to conduction band and from there to traps. In many case the energy of the radiation is used to create defects which in turn create energy levels (traps) in the forbidden gap (or energy gap). There are three ways to recover the energy stored in the solid: (1) by emission of light optically stimulated (OSL), (2) by emission of light thermally stimulated (TL), (3) by microwave absorption (EPR or ESR). Using these techniques among several applications, we will present one to find the first settlers in the northeaster region of Brazil. (author)

  16. Groundwater dating and flow-model calibration in the Kern Water Bank, California

    OpenAIRE

    Loáiciga, HA; Meillier, L; Clark, JF

    2008-01-01

    This paper describes a study of groundwater characteristics and groundwater dating in the Kern Water Bank, west of Bakersfield, Calif. The paper also presents the results of developing a calibrated groundwater-flow model for the Kern Water Bank's aquifer. The Kern Water Bank is one of the largest artificial storage and recovery operations in the southwestern United States. This study sheds light on the chemical characteristics of groundwater, on the nature of the recharge water, on the subseq...

  17. Systems biology of stored blood cells: Can it help to extend the expiration date?

    OpenAIRE

    Paglia, Giuseppe; Bernhard Ø Palsson; Sigurjonsson, Olafur E.

    2012-01-01

    With increasingly stringent regulations regarding deferral and elimination of blood donors it will become increasingly important to extend the expiration date of blood components beyond the current allowed storage periods. One reason for the storage time limit for blood components is that platelets and red blood cells develop a condition called storage lesions during their storage in plastic blood containers. Systems biology provides comprehensive bio-chemical descriptions of organisms throug...

  18. Development of the correction method of 14C groundwater dating. Evaluating the groundwater evolution and dating at the Rokkasho site

    International Nuclear Information System (INIS)

    To estimate the 14C groundwater age, groundwater evolution of dissolved inorganic carbon (DIC) needs to be investigated at a site. Groundwater evolution depends on the geochemical setting at a site. This paper proposed a correction method of 14C groundwater dating by evaluating the DIC groundwater evolution at the site of low level radioactive waste disposal in Rokkasho, Aomori prefecture, Japan. The δ13C of DICs in the shallow part of the Rokkasho site (shallower than ∼-100m elevation) showed inhomogeneous values. From the rock core chemical analysis, no inorganic carbon exited and concentrations of DIC were unchanged with depths in the shallow part. It indicates that carbonate mineral has no effect on δ13C values in the shallow part but recharging system affected on the δ13C of DIC. It is expected that both of open system and closed system or partially open and closed system recharging were taken place in shallower depth of the site. On the other hand, in the deep of the site (deeper than approx. = -100m elevation), there are shell fossils in aquifer consisting rocks. The shell fossils are dissolved based on the Na-(Ca, Mg) ion exchange reaction. It causes higher δ13C and lower 14C in the groundwater DIC at the deep part. The result of mass balance calculation of DIC concentrations and δ13C of DIC showed that DIC concentrations and δ13C was affected by some sort of reaction other than shell fossil dissolution in the deep part in the site. Correction of 14C was conducted by the IAEA equation. The corrected 14C groundwater age in this study shows good correlation with the result of other dating study derived by hydrological flow analysis compare to uncorrected age. (author)

  19. Chemical cosmology

    CERN Document Server

    Boeyens, Jan CA

    2010-01-01

    The composition of the most remote objects brought into view by the Hubble telescope can no longer be reconciled with the nucleogenesis of standard cosmology and the alternative explanation, in terms of the LAMBDA-Cold-Dark-Matter model, has no recognizable chemical basis. A more rational scheme, based on the chemistry and periodicity of atomic matter, opens up an exciting new interpretation of the cosmos in terms of projective geometry and general relativity. The response of atomic structure to environmental pressure predicts non-Doppler cosmical redshifts and equilibrium nucleogenesis by alp

  20. Dating by fission tracks in archaeology. 3. Tephrochronology and Hominid dating

    International Nuclear Information System (INIS)

    Tephras (or volcanic ashes) are excellent stratigraphic tracers. Its utilization in this domain, or tephrochronology, is shortly presented. The main archaeological utilization of the tephrochronology is related with the dating of fossil hominids, there where exist the volcano-fossil sedimentar series, at Ceylon or at East-African Rift. (L.C.)

  1. Typologies of Adolescent Dating Violence: Identifying Typologies of Adolescent Dating Violence Perpetration

    Science.gov (United States)

    Foshee, Vangie A.; Bauman, Karl E.; Linder, Fletcher; Rice, Jennifer; Wilcher, Rose

    2007-01-01

    Acts scales, the most common way of measuring partner violence, have been criticized for being too simplistic to capture the complexities of partner violence. An alternative measurement approach is to use typologies that consider various aspects of context. In this study, the authors identified typologies of dating violence perpetration by…

  2. The Role of the New "Date Rape Drugs" in Attributions about Date Rape

    Science.gov (United States)

    Girard, April L.; Senn, Charlene Y.

    2008-01-01

    This study investigates the effect of voluntary and involuntary drug use on attributions about sexual assault. The sample was composed of 280 randomly selected male and female undergraduate students. The type of drug used (GHB, alcohol, or none) and the voluntariness of the administration were varied in an unambiguous date rape scenario.…

  3. College Students' Attitudes toward Date Rape and Date Rape Backlash: Implications for Prevention Programs.

    Science.gov (United States)

    Woods, Susan; Bower, Douglas J.

    2001-01-01

    Surveyed college students regarding their acceptance of rape-myth beliefs expounded by the date rape backlash movement. Results indicated that gender, adversarial attitudes toward sexual relationships, political and sex role views, perception of false accusation vulnerability, academic honorary membership, Greek affiliation, and knowledge of a…

  4. Perceptions of Dating Behaviors and Reasons Offered to Justify Date Rape.

    Science.gov (United States)

    Bostwick, Tracy; And Others

    1995-01-01

    Reports on a study that asked undergraduate students from a large, public midwestern university to identify specific dating behaviors that indicate an interest in sex, as well as perceptions of what women do that lead men to justify raping them and perceptions of what men say to justify having raped. (Author/JPS)

  5. Dimensions of Masculinity: Relations to Date Rape Supportive Attitudes and Sexual Aggression in Dating Situations.

    Science.gov (United States)

    Truman, Dana M.; And Others

    1996-01-01

    Extends and refines existing research on the links between masculine gender roles and date rape by exploring three masculinity-related constructs: masculinity ideology, attitudes toward feminism, and homophobia. Results show that combinations of masculinity-related constructs predicted self-reported acceptance or perpetration of sexually coercive…

  6. 76 FR 34590 - Bankruptcy Filing Date Treated as Plan Termination Date for Certain Purposes; Guaranteed Benefits...

    Science.gov (United States)

    2011-06-14

    ... changes made by section 404. On July 1, 2008 (at 73 FR 37390), PBGC published in the Federal Register a... CORPORATION 29 CFR Parts 4001, 4022, and 4044 RIN 1212-AA98 Bankruptcy Filing Date Treated as Plan Termination... contributing sponsor is in bankruptcy, sections 4022 and 4044(a)(3) of ERISA are applied by treating the...

  7. Incidence and Prevalence of Dating Partner Abuse and Its Relationship to Dating Practices.

    Science.gov (United States)

    Neufeld, Jonathan; McNamara, John R.; Ertl, Melissa

    1999-01-01

    Reports on sample of women college students who completed Abusive Behavior Inventory with reference to previous six-month period and their entire dating history. Findings of six-month incidence rate of physical abuse were comparable to previously reported rates. Over 77% reported experiencing some form of psychological abuse in that 6-month…

  8. Chemical spectroscopy

    International Nuclear Information System (INIS)

    The purpose of chemical spectroscopy with neutrons is to utilize the dependence of neutron scattering cross-sections on isotope and on momentum transfer (which probes the spatial extent of the excitation) to understand fundamental and applied aspects of the dynamics of molecules and fluids. Chemical spectroscopy is divided into three energy ranges: vibrational spectroscopy, 25-500 MeV, for which much of the work is done on Be-filter analyzer instruments; low energy spectroscopy, less than 25 MeV; and high resolution spectroscopy, less than 1 MeV, which typically is performed on backscattering spectrometers. Representative examples of measurements of the Q-depenence of vibrational spectra, higher energy resolution as well as extension of the Q-range to lower values at high energy transfers, and provisions of higher sensitivities in vibrational spectroscopy are discussed. High resolution, high sensitivity, and polarization analysis studies in low energy spectroscopy are discussed. Applications of very high resolution spectroscopy are also discussed

  9. Chemical sputtering

    International Nuclear Information System (INIS)

    In this thesis, the author focuses on chemical sputtering by keV ions, treating two specific examples: the chemical effects occurring when bombarding simple condensed gases and the mechanisms of the ion-assisted etching process. First, however, the mechanism of sputtering of condensed gases in general is discussed. These mechanisms have been investigated using condensed noble gases as target material. The thesis is a compilation of articles published elsewhere. Contents: sputtering of condensed noble gases by keV heavy ions; surface distribution as an observable factor in the energy distribution of sputtered particles; reactive sputtering of simple condensed gases by keV heavy ion bombardment; mass spectra of nozzle-produced small molecular clusters of H2O, NH3, CO and CH4; mass and energy distribution of particles sputter-etched from Si in a XeF2 environment; argon-ion assisted etching of silicon by molecular chlorine; energy distribution of sputtered poly-atomic molecules. (Auth.)

  10. 38 CFR 21.5831 - Commencing date of subsistence allowance.

    Science.gov (United States)

    2010-07-01

    ... by school or establishment-course does not lead to a standard college degree. First date of class attendance. (Authority: 10 U.S.C. 2144(a)) (d) Reopened application after abandonment. Date of receipt in...

  11. The use of fly-ash particles for dating lake sediments

    International Nuclear Information System (INIS)

    Fly-ash particles comprise two particle types, spheroidal carbonaceous particles (SCP) and inorganic ash spheres (IAS). In lake sediments, these particles form an unambiguous record of atmospheric deposition of industrial pollutants. The main temporal trends of these sediment records have been found to be remarkably consistent over wide geographical areas and these features can be used to ascribe dates to cores undated by other means. SCP are the main particle type used in this way as they are easier to extract and enumerate. IAS are morphologically similar to some natural particles (volcanic, meteoritic) and therefore show a natural background concentration at all pre-industrial sediment depths. Apart from this background temporal trends are similar to SCP and IAS could be used for dating in the same way. Gaining an indication of fuel-type change, either from IAS:SCP ratio or chemical characterization of SCP enables additional dates to be added to sediment cores through comparison with documentary evidence. In the future, as 210Pb becomes progressively unable to date the post-industrial sediment record, dating using fly-ash techniques may become increasingly important. (orig.)

  12. Doing Internet Dating : In the Search for the Future Someone

    OpenAIRE

    Fürst, Henrik

    2010-01-01

    In this explorative study internet dating is studied as shared commitment to a common collective activity. Focus is on social formative emotions and internet dating in the rhythm of everyday life. The study is based on an interactionist theory/method package related to grounded theory and situational analysis. Sixty-eight participants of a Swedish internet dating site have been interviewed by e-mail. Fifteen of these interviews were followed up by a second one. Internet dating mainly occurs d...

  13. 5 CFR 880.206 - Date of death.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Date of death. 880.206 Section 880.206...) RETIREMENT AND INSURANCE BENEFITS DURING PERIODS OF UNEXPLAINED ABSENCE Procedures § 880.206 Date of death... OPM, the date of death of a missing annuitant who has been determined to be dead by an...

  14. 32 CFR 1656.14 - Postponement of reporting date.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Postponement of reporting date. 1656.14 Section... ALTERNATIVE SERVICE § 1656.14 Postponement of reporting date. (a) General. The reporting date in any of the... a Job Interview; or (3) Report to an Employer to Commence Employment. (b) Requests for...

  15. Dating methods about bulk sediments in marine environment

    International Nuclear Information System (INIS)

    With the development of science and technology progress, the studies about dating methods of sediments become more and more precise. Widely used of so many dating methods have offered reliable scientific evidence for the foundation of accurate chronostratigraphic framework in different region. Considering the difference of sedimentary environment as well as sediment types between inland and submarine, the dating method should be secerned. However, there are few articles which specially introduce the dating methods about bulk sediments in submarine environment. Based on the conclusion and summarized about many dating methods, especially focus on the sediment types and dating range,the conformable isotope dating methods (210Pb, 14C), OSL dating and comparatively dating methods (ie., Oxygen isotope curve, Paleomagnetic) which suitable for the bulk sediments in marine environment are suggested. Dating have an very important function in marine geological studies. In order to enhance the veracity and reliability of the dating data, the proper methods based on sediment types and estimated age range are selected. On the other hand,the progress cross-comparison during different dating methods are given. (authors)

  16. A Survey of Archaeological Samples Dated in 1984

    DEFF Research Database (Denmark)

    Mejdahl, Vagn

    A survey is given of archaeological samples dated in 1984 at the Nordic Laboratory for Thermoluminescence Dating. A total of 79 samples were dated, 49 of which were burnt stones. All results were corrected for fading as measured for samples stored for four weeks at room temperature. The alpha dose...

  17. A Survey of Archaeological Samples Dated in 1985

    DEFF Research Database (Denmark)

    Mejdahl, Vagn

    1986-01-01

    A survey is given of archaeological samples received for dating in 1985 at the Nordic Laboratory for Thermoluminescence Dating. A total of 66 samples were dated, 42 of which were burnt stones. All results were corrected for short-term fading as measured for samples stored at room temperature for...

  18. 9 CFR 114.13 - Expiration date determination.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Expiration date determination. 114.13... BIOLOGICAL PRODUCTS § 114.13 Expiration date determination. Unless otherwise provided for in a Standard Requirement of filed Outline of Production, the expiration date for each product shall be computed from...

  19. 9 CFR 114.12 - Expiration date required.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Expiration date required. 114.12... BIOLOGICAL PRODUCTS § 114.12 Expiration date required. Each serial or subserial of biological product prepared in a licensed establishment shall be given an expiration date determined in accordance with...

  20. 76 FR 20249 - Update Station License Expiration Dates

    Science.gov (United States)

    2011-04-12

    ... COMMISSION 47 CFR Part 73 Update Station License Expiration Dates AGENCY: Federal Communications Commission... reflect the current license expiration dates for radio and television broadcast stations. The current version of the rule specifies license expiration dates from 2011 through 2014 for radio stations and...

  1. 21 CFR 1302.05 - Effective dates of labeling requirements.

    Science.gov (United States)

    2010-04-01

    ... PACKAGING REQUIREMENTS FOR CONTROLLED SUBSTANCES § 1302.05 Effective dates of labeling requirements. All... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Effective dates of labeling requirements. 1302.05..., on or before the effective date established in the final order for the transfer or addition....

  2. Magnetostratigraphic dating of early humans in China

    Science.gov (United States)

    Zhu, Rixiang; An, Zhisheng; Potts, Richard; Hoffman, Kenneth A.

    2003-06-01

    China is a key area for research into human occupation in the Old World after the initial expansion of early humans out of Africa. Reliable age determinations are pivotal for assessing the patterns of human evolution and dispersal in this region. This paper reviews magnetostratigraphic studies of some early Pleistocene strata bearing hominin remains and/or artifact stone tools from northern to southern China. The quality and reliability of the paleomagnetic dates are also evaluated. New magnetostratigraphic results for the Xihoudu Paleolithic site in north-central China are also presented. Among the few hominin or Paleolithic sites in China from the early Pleistocene, five have been well investigated. Three of these are in northern China at Xiaochangliang, Donggutuo and Gongwangling; the remaining two in southern China at Longgupo and Yuanmou. Considerable progress has been made during the past three decades towards paleomagnetically dating these sites. Indeed, the age estimates at Xiaochangliang and Gongwangling have been widely accepted. Magnetostratigraphic consensus about the age of the Donggutuo site has also been reached. However, the age determination for the two sites in southern China is still contested. The integration of rock-magnetic stratigraphy with magnetic polarity stratigraphy has resulted in a determined age of 1.36 Ma for a stone tool-containing layer of lacustrine sediments at the Xiaochangliang site in the Nihewan Basin. Lithostratigraphic constraints have significantly contributed to determining the age of Lantian Homo erectus at Gongwangling, which occurred in a loess-paleosol sequence of the southern Loess Plateau. Its age, paleomagnetically derived, is about 1.15 Ma. These two paleomagnetic ages suggest an expansion and flourishing of human groups from northern to north-central China during the early Pleistocene. This suggestion has been reinforced by our new magnetostratigraphic age estimate of about 1.27 Ma for the Xihoudu site as will be

  3. The physical and chemical evolution of protostellar disks. The growth of protostellar disks: Progress to date

    Science.gov (United States)

    Stahler, Steven W.

    1993-01-01

    This study constitutes one part of our multi-disciplinary approach to the evolution of planet-forming disks. The goal is to establish the disks' thermal and mechanical properties as they grow by the infall of their parent interstellar clouds. Thus far, significant advances toward establishing the evolving surface density of such disks was made.

  4. Genetic Algorithm for Scheduling Problem of Chemical Batch Process with Due Date Constraints

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The intense competition in the current marketplace ha s forced firms to reexamine their methods of doing business, using superior manu facturing practices in the form of just-in-time (JIT), production with JIT pra ctices pursue completion on time and zero inventory, which is often instruct ed according to the custom's demand or the sale contract. Earliness and tardine ss are undesirable because both of them will bring the extra cost, cost will als o be increased by some factors such as operation conditio...

  5. Dating of polyhalite and langbeinite: preliminary results from German Zechstein

    Science.gov (United States)

    Neubauer, Franz; Schorn, Anja; Leitner, Christoph; Genser, Johann

    2013-04-01

    Evaporite mélanges often form decollément surfaces of major extensional and contractional allochthons because of the very low shear resistance of halite. Due to the deposition of evaporites during an early stage of passive continental margin formation, evaporites are commonly overlain by thick successions of carbonates and/or siliciclastic rocks deposited during the main thermal subsidence stage of the passive margin formation. The most common cases of evaporite mélanges are such (1) at passive continental margins, where they are deformed during gravity-driven extension, commonly raft tectonics, in an extensional geodynamic setting, (2) in external foreland fold-thrust belts within a convergent geodynamic setting, and (3) in salt diapirs. In all these cases, halite is strongly deformed by late-stage deformation and only sulphate lenses composed of anhydrite and gypsum preserve early deformational stages. Dating of K-sulphates may allow the recognition of early stages of deformation although this method is poorly applied (Renne et al., 2001). Knowledge of the limitations of K-sulphate chronometers of langbeinite and polyhalite may allow, therefore, dating of full history of evaporite mélanges (for polyhalite, see Leitner et al., 2012). Polyhalite has the chemical formula [K2Ca2Mg(SO4)4?2 H2O] and commonly occurs in sedimentary evaporite successions. The mineral can be synthesised under laboratory conditions by a reaction of gypsum with appropriate solutions in the ternary system K2SO4-MgSO4-H2O at temperatures above 70 ° C (Freyer and Voigt, 2003). At lower temperatures, polyhalite crystallisation slows down (Wollmann, 2010). In nature, polyhalite, which is stable between ~ room temperature (0-25 ° C) and 255-343 ° C (Wollmann et al., 2008) or 285 ° C (Fischer et al., 1996), most commonly forms early-diagenetically or secondarily (Warren, 2006 and Leitner et al., 2012 and references therein). The secondary mineral langbeinite [K2Mg2(SO4)3],whose lower

  6. Palm Date Fibers: Analysis and Enzymatic Hydrolysis

    Directory of Open Access Journals (Sweden)

    Mohammad J. Taherzadeh

    2010-11-01

    Full Text Available Waste palm dates were subjected to analysis for composition and enzymatic hydrolysis of their flesh fibers. The fruit contained 32% glucose and 30% fructose, while the water-insoluble fibers of its flesh consisted of 49.9% lignin and 20.9% polysaccharides. Water-insoluble fibers were settled to 55% of its initial volume in 12 h. The presence of skin and flesh colloidal fibers results in high viscosity and clogging problems during industrial processes. The settling velocity of the fibers was improved by enzymatic hydrolysis. Hydrolysis resulted in 84.3% conversion of the cellulosic part of the fibers as well as reducing the settling time to 10 minutes and the final settled volume to 4% of the initial volume. It implies easier separation of the fibers and facilitates fermentation processes in the corresponding industries. Two kinds of high- and low-lignin fibers were identified from the water-insoluble fibers. The high-lignin fibers (75% lignin settled easily, while the low-lignin fibers (41.4% lignin formed a slurry suspension which settled very slowly. The hydrophilicity of these low-lignin fibers is the major challenge of the industrial processes.

  7. Photoreceptors mapping from past history till date.

    Science.gov (United States)

    Parihar, Parul; Singh, Rachana; Singh, Samiksha; Tripathi, Durgesh Kumar; Chauhan, Devendra Kumar; Singh, Vijay Pratap; Prasad, Sheo Mohan

    2016-09-01

    The critical source of information in plants is light, which is perceived by receptors present in plants and animals. Receptors present in plant and animal system regulate important processes, and knowing the chromophores and signalling domains for each receptor could pave a way to trace out links between these receptors. The signalling mechanism for each receptor will give insight knowledge. This review has focussed on the photoreceptors from past history till date, that have evolved in the plant as well as in the animal system (to lesser extent). We have also focussed our attention on finding the links between the receptors by showing the commonalities as well as the differences between them, and also tried to trace out the links with the help of chromophores and signalling domain. Several photoreceptors have been traced out, which share similarity in the chromophore as well as in the signalling domain, which indicate towards the evolution of photoreceptors from one another. For instance, cryptochrome has been found to evolve three times from CPD photolyase as well as evolution of different types of phytochrome is a result of duplication and divergence. In addition, similarity between the photoreceptors suggested towards evolution from one another. This review has also discussed possible mechanism for each receptor i.e. how they regulate developmental processes and involve what kinds of regulators and also gives an insight on signalling mechanisms by these receptors. This review could also be a new initiative in the study of UVR8 associated studies. PMID:27387671

  8. An improved technique for fission track dating

    International Nuclear Information System (INIS)

    The necessity of improving the fission track dating (FTD) technique both at home and abroad is illustrated. The ways of making such improvement are also proposed. It is suggested to calibrate the constant b value of the uranium standard glass by using the method of fission products activity. The 3 kinds of uranium standard glass which have been calibrated are NBS SRM962a, UB1 and UB2. An established new method σ·Φ ρd/b, to measure neutron fluence, avoids the influence of the varying neutron spectrum on measuring neutron fluence. The improved etching technique for fission tracks in zircon adopted a two-step method which includes the molten alkali system etching using NaOH + KOH and the mixed acid system etching using HNO3 + HF; this technique results in adequate track etching, increased track clarity and less interference. In this way the intensity of tracks is authentically reflected. Dividing angular zone in accordance with the angular distribution of spontaneous fission track on the crystal surface of minerals to count the tracks and using the improved etching technique to remove the non-uniform angular distribution of spontaneous fission tracks in zircon, ensure the accuracy of tracks count. The improved FTD techniques were used to finish Laboratory Standardized Calibration. The tests using international FTD age standards samples have proved that above mentioned techniques are reliable and practical in obtaining the accurate FTD data. (8 tabs.; 3 figs.)

  9. Dating of wines, neutrino and radioactivity

    International Nuclear Information System (INIS)

    14C dating of wines requires a heavy experimental technique implying the preparation of an alcoholic distillate and the use of a beta-radiation detector. Moreover the results have to be corrected in case the wine underwent a chaptalization process with sugar of a different age from that of grapes. A new method based on the detection of 137Cs is presented. 137Cs is an artificial gamma isotope that is produced in nuclear fission. Radioactivity measurement campaigns show a strong correlation between the quantity of 137Cs in wine and the year of production. The concentration of 137Cs varies from no traces in 1950 (<6 mBq/l) to 350 mBq/l in 1955 to 1070 mBq/l in 1963, since mid sixties a continuous decrease appears that lasts till now except for a short period pointed in 1986 when it peaks to 150 mBq/l, for 2000 the concentration is a few mBq/l. This chaotic curve is mainly due to the fallout of the atmospheric nuclear tests, that took place in the 1950-1963 years, and to the Chernobyl accident in 1986. Today this technique allows to check the validity of the year of production of a less than 50 years old bottled wine and it does not require the uncorking of the bottle. (A.C.)

  10. The determination of age of the fault activities of Shougou Hill, Guangzhou by thermoluminescence dating and nuclear fission track dating

    International Nuclear Information System (INIS)

    The age of the fault activities had been determined by TL dating and nuclear fission track dating. The results show that the fault of Shougou Hill had large and intense activities in mid-cenozoic era, however, intense activities still occurred in early pleistocene and mid-pleistocene. The last activity of the fault occurred 430 000 years ago. The data of TL dating are conformable with data of nuclear fission track dating

  11. Proximal antecedents to violent events in adolescent dating relationships.

    Science.gov (United States)

    Stephenson, Pamela S; Martsolf, Donna S; Draucker, Claire Burke

    2011-01-01

    Dating violence affects 25-60% of adolescents. This study developed a typology of proximal antecedents to violent events in adolescent dating relationships. Descriptions of 307 dating violence events were extracted from transcribed interviews with 87 young adults who experienced dating violence as adolescents. Verbatim text preceding the description of each violent event was identified as a proximal antecedent. Cross-case analysis was used to develop a typology of five antecedent categories: "pulling away,"  "demanding obedience," "discovering involvement with a rival," "defining the relationship," "demonstrating disrespect." Practitioners can use this typology to engage teens in discussions of factors that precede dating violence events. PMID:21992258

  12. Positives and negatives of online dating according to women 50.

    Science.gov (United States)

    Vandeweerd, Carla; Myers, Jaime; Coulter, Martha; Yalcin, Ali; Corvin, Jaime

    2016-01-01

    To understand the positives and negatives of online dating according to the lived experience of older women, telephone interviews were conducted with 45 women ages 50+ who date online. Interviews were audio recorded, transcribed verbatim, and thematically team coded. The opportunity to expand one's social network for both friendships and romantic partners, the ability to control dating risks and pace of relationship formation, and knowing more about one's partner were significant reported benefits of online dating. Dating online also includes unique risks, such as pervasive lying, attempted financial exploitation in the form of scammers, and unwanted electronic sexual aggression. PMID:27191792

  13. Thermoluminescence dating of pottery from Sringaverapura -- A Ramayana site

    International Nuclear Information System (INIS)

    The first thermoluminescence (TL) dates of pottery from a Ramayana associated site are reported. The TL dates for pre-NBPW Black-Slipped Ware levels are 730 and 765 B.C., while radiocarbon date takes the earliest Black Slipped Ware Level (for which no TL dates are available) to 905 B.C. (uncorrected). For the OCW level, three TL dates are available which range from 1035 B.C. to 875 B.C. The early NBPW period believed to be associated with the Ramayana episode will thus be post-750 B.C. (author)

  14. Electron spin resonance as a method of dating

    International Nuclear Information System (INIS)

    Electron spin resonance (ESR) dating is closely related to thermoluminescence (TL) dating. The principle and procedures of ESR are described together with the application to archaeological materials excavated at Petralona cave in Greece. Atomic models of defects responsible for TL and ESR in calcite are discussed. The age is deduced from the archaeological dose, the total dose of the natural radiation determined by ESR signal intensities, and from the dose rate. The ages by ESR dating are compared with those by TL and 14C dating and also by U-Th dating. The applications to geological and anthropological materials are described with main emphasis on cave deposits. (author)

  15. 7 CFR 987.164 - Shipments of product dates and disposition of restricted dates in approved product outlets.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Shipments of product dates and disposition of restricted dates in approved product outlets. 987.164 Section 987.164 Agriculture Regulations of the..., Vegetables, Nuts), DEPARTMENT OF AGRICULTURE DOMESTIC DATES PRODUCED OR PACKED IN RIVERSIDE...

  16. [Chemical constituents from Spatholobus sinensis].

    Science.gov (United States)

    Yin, Ting; Liu, Hua; Wang, Bin; Tu, Guang-Zhong; Liang, Hong; Zhao, Yu-Ying

    2008-01-01

    Spatholobus sinensis is a plant of the Spatholobus genus (Leguminosae family). Its caulis are used as "ji-xue-teng" regionally. However, to our knowledge, no phytochemical investigation on S. sinensis has been reported to date. In this study, eight compounds were isolated from the ethanol extract of the caulis of S. sinensis, by solvents extraction and column chromatography methods. By analysis of their physic-chemical constants and spectral data, the structures of 8 compounds were identified as spatholosineside A (1), 2',4',5,7-tetrahydroxyisoflavone (2), isoliquiritigenin (3), lupinalbin A (4), coumestrol (5), naringenin (6), protocatechuic acid (7), leonuriside A (8). Compound 1 is a new compound. PMID:18357735

  17. Dating hapuka otoliths using 210 Pb/226 Ra, with comments on dating orange roughy otoliths

    International Nuclear Information System (INIS)

    It is shown that Hapuka otoliths cannot be reliably dated using the 210 Pb/ 226 Ra method because contrary to previous assumptions, excess 210 Pb is incorporated into the outer layers of otoliths which have been taken from old fish, though the 226 Ra incorporation remains normal. This is shown to apply also to Orange Roughy otoliths. Ages based on calculations using previously published methods will be artificially old. (author). 13 refs., 2 tabs., 3 figs

  18. Thermoluminescence dates for the Lake Mungo aboriginal fireplaces and the implications for radiocarbon dating

    International Nuclear Information System (INIS)

    During the Quaternary period in Australia large areas of western New South Wales and northern Victoria were covered by hundreds of lakes, both large and small. Nearly all are dry today but some may still be recognized by the long low dunes that follow the eastern shorelines. Many traces of early human occupation have been found along the shorelines of nearly all the major lakes and some of the best exposures have occurred on the lunette along the eastern shore of Lake Mungo. This lunette, has suffered massive erosion in recent times and this has uncovered the sites of many ancient fireplaces. Charcoal from some of these fireplaces has been dated by Barbetti and Polach (1973) using the radiocarbon method and the ages place the lakeside dwellers at Mungo in an area of Australian prehistory around 30 000 years ago. The baked sediment from below the fireplaces appears to have been heated to a temperature in excess of 400oC according to archaeomagnetic studies carried out by Barbetti (1973) and this indicated that the fireplaces might lend themselves to the technique of thermoluminescence (TL) dating. The results of the TL dating programme are described elsewhere. (author)

  19. Optimized preparation for large surface area activated carbon from date (Phoenix dactylifera L.) stone biomass

    International Nuclear Information System (INIS)

    The preparation of activated carbon from date stone treated with phosphoric acid was optimized using rotatable central composite design of response surface methodology (RSM). The chemical activating agent concentration and temperature of activation plays a crucial role in preparation of large surface area activated carbons. The optimized activated carbon was characterized using thermogravimetric analysis, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, powder X-ray diffraction, and Fourier transform infrared spectroscopy. The results showed that the larger surface area of activated carbon from date stone can be achieved under optimum activating agent (phosphoric acid) concentration, 50.0% (8.674 mol L−1) and activation temperature, 900 °C. The Brunauer–Emmett–Teller (BET) surface area of optimized activated carbon was found to be 1225 m2 g−1, and thermogravimetric analysis revealed that 55.2% mass of optimized activated carbon was found thermally stable till 900 °C. The leading chemical functional groups found in the date stone activated carbon were aliphatic carboxylic acid salt ν(C=O) 1561.22 cm−1 and 1384.52 cm−1, aliphatic hydrocarbons ν(C–H) 2922.99 cm−1 (C–H sym./asym. stretch frequency), aliphatic phosphates ν(P–O–C) 1054.09 cm−1, and secondary aliphatic alcohols ν(O–H) 3419.81 cm−1 and 1159.83 cm−1. - Highlights: • RSM optimization was done for the production of large surface area activated carbon. • Two independent variables with two responses were selected for optimization. • Characterization was done for surface area, morphology and chemical constituents. • Optimized date stone activated carbon achieved surface area 1225 m2 g−1

  20. Dating sediment cores from Hudson River marshes

    International Nuclear Information System (INIS)

    There are several methods for determining sediment accumulation rates in the Hudson River estuary. One involves the analysis of the concentration of certain radionuclides in sediment core sections. Radionuclides occur in the Hudson River as a result of: natural sources, fallout from nuclear weapons testing and low level aqueous releases from the Indian Point Nuclear Power Facility. The following radionuclides have been studied in the authors work: Cesium-137, which is derived from global fallout that started in the 1950's and has peaked in 1963. Beryllium-7, a natural radionuclide with a 53 day half-life and found associated with very recently deposited sediments. Another useful natural radionuclide is Lead-210 derived from the decay of Radon-222 in the atmosphere. Lead-210 has a half-life of 22 years and can be used to date sediments up to about 100 years old. In the Hudson River, Cobalt-60 is a marker for Indian Point Nuclear Reactor discharges. The author's research involved taking sediment core samples from four sites in the Hudson River Estuarine Research Reserve areas. These core samples were sectioned, dried, ground and analyzed for the presence of radionuclides by the method of gamma-ray spectroscopy. The strength of each current pulse is proportional to the energy level of the gamma ray absorbed. Since different radionuclides produce gamma rays of different energies, several radionuclides can be analyzed simultaneously in each of the samples. The data obtained from this research will be compared to earlier work to obtain a complete chronology of sediment deposition in these Reserve areas of the river. Core samples may then by analyzed for the presence of PCB's, heavy metals and other pollutants such as pesticides to construct a pollution history of the river

  1. CHEMICAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Calvin, Melvin

    1965-06-01

    How did life come to be on the surface of the earth? Darwin himself recognized that his basic idea of evolution by variation and natural selection must be a continuous process extending backward in time through that period in which the first living things arose and into the period of 'Chemical Evolution' which preceded it. We are approaching the examination of these events by two routes. One is to seek for evidence in the ancient rocks of the earth which were laid down prior to that time in which organisms capable of leaving their skeletons in the rocks to be fossilized were in existence. This period is sometime prior to approximately 600 million years ago. The earth is believed to have taken its present form approximately 4700 million years ago. We have found in rocks whose age is about 1000 million years certain organic molecules which are closely related to the green pigment of plants, chlorophyll. This seems to establish that green plants were already fluorishing prior to that time. We have now found in rocks of still greater age, namely, 2500 million years, the same kinds of molecules mentioned above which can be attributed to the presence of living organisms. If these molecules are as old as the rocks, we have thus shortened the time available for the generation of the complex biosynthetic sequences which give rise to these specific hydrocarbons (polyisoprenoids) to less than 2000 million years.

  2. The players of micro-dating: Individual and gender differences in goal orientations toward micro-dating apps

    OpenAIRE

    Carpenter, Christopher J.; McEwan, Bree

    2016-01-01

    Dating apps on smartphones have brought speed dating on the Internet to a new level. This exploratory investigation sought to determine what kinds of people use these apps, what their motivations are, and what precautions they take before meeting someone. One hundred and seventy-three non-users and 57 current users of dating apps were surveyed. The data suggest that the strongest motive for using dating apps is not for dating or sex, but for entertainment. On the other hand, the more frequent...

  3. Toward sufficient reduction of radio-impurities for 32Si sediment age dating

    International Nuclear Information System (INIS)

    This project is focused on developing a geochronology tool enabling age dating of coastal marine sediments in the 100-1000 year age range. The technique employs the 32Si/32P radio-chronometer with an ultra-lowbackground gas proportional beta detector with a background count rate approaching 10 counts per day (cpd), which will require significant decontamination of radiogenic nuclides present in the original sediment samples. This paper describes the multiple physical and chemical separation methods employed to maintain a high final chemical yield of P while reducing the radiogenic contributions. The final purified 32P samples had, on average 100 ± 7 % chemical yields with no quantifiable gamma emissions present. (author)

  4. Drivers of hemispheric differences in return dates of mid-latitude stratospheric ozone to historical levels

    Directory of Open Access Journals (Sweden)

    H. Garny

    2013-08-01

    Full Text Available Chemistry-climate models (CCMs project an earlier return of northern mid-latitude total column ozone to 1980 values compared to the southern mid-latitudes. The chemical and dynamical drivers of this hemispheric difference are investigated in this study. The hemispheric asymmetry in return dates is a robust result across different CCMs and is qualitatively independent of the method used to estimate return dates. However, the differences in dates of return to 1980 levels between the southern and northern mid-latitudes can vary between 0 and 30 yr across the range of CCM projections analyzed. Positive linear trends in ozone lead to an earlier return of ozone than expected from the return of Cly to 1980 levels. This forward shift is stronger in the Northern than in the Southern Hemisphere because (i trends have a larger effect on return dates if the sensitivity of ozone to Cly is lower and (ii the trends in the Northern Hemisphere are stronger than in the Southern Hemisphere. An attribution analysis performed with two CCMs shows that chemically-induced changes in ozone are the major driver of the earlier return of ozone to 1980 levels in northern mid-latitudes; therefore transport changes are of minor importance. This conclusion is supported by the fact that the spread in the simulated hemispheric difference in return dates across an ensemble of twelve models is only weakly related to the spread in the simulated hemispheric asymmetry of trends in the strength of the Brewer–Dobson circulation. The causes for chemically-induced asymmetric ozone trends relevant for the total column ozone return date differences are found to be (i stronger increases in ozone production due to enhanced NOx concentrations in the Northern Hemisphere lowermost stratosphere and troposphere, (ii stronger decreases in the destruction rates of ozone by the NOx cycle in the Northern Hemisphere lower stratosphere linked to effects of dynamics and temperature on NOx

  5. Groundwater dating by means of isotopes

    International Nuclear Information System (INIS)

    A short review is given of method for dating old groundwater by isotopetechniques. The carbon-14 method is then treated in detail; Carbon dioxide, released by root respiration of plants, and by decomposition of organic matter in the soil, is dissolved in soil water. The production of carbon dioxide in the root zone is high and the 14C/12C ratio is therefore assumed to be the same as in the plants. The residence time of water in the groundwater zone may then be computed, according to the laws of radioactive decay. No attempts have been made to compute the changes in the carbon-14 content of the soil air due to weathering. To do this, one would need to consider diffusion of gaseous carbon dioxide into and out of the soil. The amount of carbon entering the water through weathering in the groundwater zone may be compute if certain assumptions are made. To know if these assumptions are valid for the water of a special area, detailed knowledge about the area is required. In this report, an attempt is made to follow the changes in the composition of the water as the water moves through the ground. The differentiated equilibrium equations of the carbon dioxide system and the ionic balance are used for the calculations. It is assumed that when calcite is present in the ground, weathering of other minerals may be neglected. In order to test its usefulness, the method has been tried on groundwater from a borehole in Kraakemaala, Sweden. The results are very much dependent on the values of some of the parameters used in the calculations. The σ 13C values especially have a great influence on the calculated age. As long as additional information on conditions at different depth remains unavailable, it seems impossible to determine the age of water with any accuracy. Only a range, which sometimes embraces several thousand years, can be given. A good aid to a better estimate of the age would be obtained if samples of water along a flow path were available. One way to get such

  6. On the optical dating signal from quartz

    International Nuclear Information System (INIS)

    A series of experiments were conducted on the optical dating signal from quartz. Results are presented showing the quantitative equivalence of the light sums of the optically stimulated luminescence (OSL) emitted by quartz under exposure to 514.5 nm light and that of the quartz ''325oC'' thermoluminescence (TL) peak. Discrepancies observed between the OSL and TL light sums under ''typical'' measurement conditions (i.e. when OSL is measured at ∼ 293 K and the 325oC TL peak is measured at ∼ 600 K, in both cases observing ultraviolet emissions) are attributed to thermal quenching of luminescence at the recombination centres (non-radiative recombination). The bleach response spectrum (using bleaching wavebands ranging from 400.6 Δ 10.1 nm to 899.1 Δ 13.2 nm) of OSL from quartz (514.5 nm stimulation) was measured and found, within experimental errors, to be indistinguishable from that previously measured for the 325oC TL peak of quartz. Also measured was the thermal dependence of the OSL signal under stimulation by various wavebands ranging from 480.9 Δ 6.8 nm to 861.1 Δ 12.5 nm, in the temperature range from ∼ 100 to ∼ 500 K. Strong thermal assistance was found for all wavebands tested, with the magnitude of thermal assistance increasing as stimulation wavelength increased-behaviour not inconsistent with photoionization. Supplementary work showed that OSL production involves a single-photon-absorption untrapping step. Supplementary work showed that OSL production involves a single-photon-absorption untrapping step. It is concluded that the OSL emitted by quartz under exposure to visible light, and the 325oC TL peak of quartz, originate from one and the same trapped electron population. Furthermore, optical untrapping of this trapped charge population, resulting in both the bleaching of the 325oC TL peak and the prompt emission of OSL, proceeds by the same mechanism: single-photon-absorption photoionization direct to the conduction band. (author)

  7. TL dating of vases with elephant ears in Yuan Dynasty

    International Nuclear Information System (INIS)

    Thermoluminescence (TL) dating using an activation method in pre-dose technique was described. Three vases in underglaze blue with elephant ears and one vase in underglaze red with elephant ears in Yuan Dynasty were dated by this method. The results show that the TL ages are all less than 100 a B.P., and in which sbc 648 and sbc 649 were imitated in recent years. This method is quick, convenient and reliable for porcelain dating with the age of less than 1000 a B.P.. As a comparison, a porcelain sample with underglaze blue in Yuan Dynasty was dated too, and its TL age is 620 ± 140 B.P.. In addition, some complex factors associated with dating have been discussed and a resolution has been raised, which will help improve the accuracy of TL dating. (authors)

  8. Endemic insular and coastal Tunisian date palm genetic diversity.

    Science.gov (United States)

    Zehdi-Azouzi, Salwa; Cherif, Emira; Guenni, Karim; Abdelkrim, Ahmed Ben; Bermil, Aymen; Rhouma, Soumaya; Salah, Mohamed Ben; Santoni, Sylvain; Pintaud, Jean Christophe; Aberlenc-Bertossi, Frédérique; Hannachi, Amel Salhi

    2016-04-01

    The breeding of crop species relies on the valorisation of ancestral or wild varieties to enrich the cultivated germplasm. The Tunisian date palm genetic patrimony is being threatened by diversity loss and global climate change. We have conducted a genetic study to evaluate the potential of spontaneous coastal resources to improve the currently exploited Tunisian date palm genetic pool. Eighteen microsatellite loci of Phoenix dactylifera L. were used to compare the genetic diversity of coastal accessions from Kerkennah, Djerba, Gabès and continental date palm accessions from Tozeur. A collection of 105 date palms from the four regions was analysed. This study has provided us with an extensive understanding of the local genetic diversity and its distribution. The coastal date palm genotypes exhibit a high and specific genetic diversity. These genotypes are certainly an untapped reservoir of agronomically important genes to improve cultivated germplasm in continental date palm. PMID:26895027

  9. Production and testing of dates oil and its bio diesel

    International Nuclear Information System (INIS)

    Date palms are very famous trees in Iraq and some other countries. The date oil might use as a fuel in a compression ignition engines. Also, this oil can be used as a raw material to produce a date-bio diesel. In this paper, a new method to extract oil from dates is showed and synthesized bio diesel from this oil. Full description to extraction as well as to Transesterification methods is achieved. The main fuel properties tests are done on the oil and the date-bio diesel. The caloric values, viscosity, density, pour point, cloud point and diesel index are tested for date's oil and for its bio diesel. A comparison with diesel oil is hold to show the utility of this oil and its bio diesel for using in compression ignition engines. (author)

  10. TUNISIAN DATE PALM RACHIS USED AS AN ALTERNATIVE SOURCE OF FIBRES FOR PAPERMAKING APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Ramzi Khiari

    2011-02-01

    Full Text Available Every year, significant amounts of date palm rachises are accumulated in Tunisia. The rational valorisation of this renewable resource is therefore imperative, in order to fulfil the sustainability approach. In this context, this work aims to study the potential use of date palm rachises as a raw material for papermaking and to compare it with other sources of lignocellulosic fibres, such as wood, non-wood species, and agricultural wastes. For this purpose, soda-anthraquinone pulping of date palm rachis was performed giving rise to a yield of 45% (w/w. This value is similar to that obtained by pulping non-wood materials and is higher than that corresponding to the pulping of agricultural residues. The resulting pulps were subsequently refined using a PFI mill refiner at 0, 500, 1500, and 3000 revolutions, screened through a 0.15 mm mesh size sieve and used to produce conventional handsheets. Both pulps and papers were fully characterized in terms of morphological, chemical and physical properties, according to commonly used standards. The physical properties of the prepared handsheets were very similar to those displayed by other papers made of common lignocellulosic fibres. Furthermore, the pulps exhibited a good drainability together with excellent mechanical properties of the ensuing papers. For these reasons, date palm rachises could be considered as a potential source of fibres for papermaking applications.

  11. Production of activated carbon from raw date palm fronds by ZnCI/sub 2/ activation

    International Nuclear Information System (INIS)

    Annually a large volume of date palm frond waste is produced in Saudi Arabia as a result of the pruning of date palm trees. In this research activated carbon (AC) was prepared from date frond through a single step chemical activation method by ZnCl/sub 2/. The influence of ZnCl/sub 2/ concentrations (in the range of 0, 20, 40, 60 and 80 percentage) on the surface areas, pore volumes and carbon yield of ACs prepared from raw date frond (RDF) was studied with various analytical techniques. The RDF and ACs were characterized by Thermogravimetric Analysis (TGA), nitrogen adsorption Brunauer-Emmett-Teller (BET) for surface areas and pore volumes, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) for surface morphology and elemental composition respectively. In the present study we have obtained the highest BET surface area 1581.67 m/sup 2/g/sup -1/ and total pore volume 0.629 cm/sup 3/ g/sup -1/ at 60 percentage ZnCl/sub 2/ concentration. The percentage yield of ACs increased with increase in ZnCl/sub 2/ concentration and reached to 39 percent at 60 percent ZnCl/sub 2/ concentration. The surface area obtained in the present study is highest amongst the results report in literature. (author)

  12. Dating of the archaeological site 'El Tigre' by the thermoluminescent method

    International Nuclear Information System (INIS)

    Full text: The dating of pre hispanic pottery, is supported by techniques such as stratigraphy, typology, in physical and chemical procedures, as the analysis of 14C and the thermoluminescence (TL). The last one permits us obtain absolute dating of archaeological pottery with an acceptable precision. In this work we apply the applied the thermoluminescent technique to verify the age of the Pre-Classic and Classic Terminal periods proposed for the archaeological site 'El Tigre', Campeche. The samples were obtained during a work period and the radiation of the ground of background (emitted by the ground), as well as the contribution of the cosmic radiation was measured with thermoluminescent dosemeters of LiF: Mg,Cu,P + PTFE, put in the sample zone. The preliminary results indicate that not all the analyzed samples can be dated. The viability of the dating of the samples is discussed based on the fact and function of the presence of certain crystalline phases such as calcite and quartz. The discussion is complemented emphsizing the importance of handling the conditions of handling of samples. (Author)

  13. Socio-economic characterisation of date palm (Phoenix dactylifera L.) growers and date value chains in Pakistan.

    Science.gov (United States)

    Fatima, Ghayoor; Khan, Iqrar Ahmad; Buerkert, Andreas

    2016-01-01

    Increasing food production to feed its rapidly growing population is a major policy goal of Pakistan. The production of traditional staples such as rice (Oryza sativa L.) and bread wheat (Triticum aestivum L.) has been intensified in many regions, but not in remote, drought-ridden areas. In these arid, marginal environments dates and their by-products are an option to complement staples given their high nutritive value and storability. To fill knowledge gaps about the role of date palm in the household (HH) income of rural communities and the structure of date value chains, this project studied date palm production across six districts in four provinces of Pakistan. During 2012-2013 a total of 170 HHs were interviewed with a structured questionnaire using a snowball sampling approach. The results showed that most of the HH were headed by males (99 %) who were married (74 %) and often illiterate (40 %). Agriculture was the main occupation of date palm growers (56 %), while a few coupled agricultural activities with business (17 %) or extra-farm employment opportunities (government 9 %; private sector 8 %). Date sales contributed >50 % to the total income of 39 % of HH and 90-100 % to 24 % of HH. Overall farmers grew a total of 39 date palm cultivars and cultivated an average of 409 ± 559 mature date palms. The majority of the respondents sold dates to commission agents (35 %), contractors (22 %) and wholesalers (21 %), while 28 % of HH cultivated date palms only for self-consumption. Date palm growers had only limited knowledge about high quality date cultivars, optimized farm management and about effective post-harvest conservation. Changes in extension and marketing efforts are needed to allow farmers to better exploit value chains in date thereby reaping higher benefits from improved market access to secure their often marginal income. PMID:27536506

  14. Physical dating violence among college students in Chile

    OpenAIRE

    Lehrer, Jocelyn A.; Lehrer, Vivian L.; Lehrer, Evelyn Lilian; Zhao, Zhenxiang

    2007-01-01

    Dating violence is a serious public health concern both per se and because victimization in the young adult years can be a precursor to more severe incidents of domestic violence later, in the context of cohabitation or marriage. To date, no quantitative studies have examined dating violence among college students in Chile. To address this gap, a survey on this topic was administered to students at a major public university. The present analyses focused on the female sample (n=441). Generaliz...

  15. A revised dated phylogeny of the arachnid order Opiliones

    OpenAIRE

    Sharma, Prashant P; Giribet, Gonzalo

    2014-01-01

    Dating the Opiliones tree of life has become an important enterprise for this group of arthropods, due to their ancient origins and important biogeographic implications. To incorporate both methodological innovations in molecular dating as well as new systematic discoveries of harvestman diversity, we conducted total evidence dating on a data set uniting morphological and/or molecular sequence data for 47 Opiliones species, including all four well-known Palaeozoic fossils, to test the placeme...

  16. THE VALIDITY AND RELIABILITY OF ATTITUDES TOWARDS DATING VIOLENCE SCALES

    OpenAIRE

    Ahmet YUMUŞAK; ŞAHİN, Rukiye

    2014-01-01

    ABSTRACT: In this study, The Attitudes towards Dating Violence Scales was adapted into Turkish and their validity and reliability were determined. The sample of the study was determined through random sampling method from students of a Middle Black Sea Region University in 2012-2013 academic years. "The Attitudes towards Dating Violence Scales" were developed by Price, Byers and Dating Violence Research Team (1999) on the purpose of determining the male and female participants' attitudes ...

  17. Dating burial practices and architecture at Lepenski Vir

    OpenAIRE

    Bonsall, Clive; Radovanović, Ivana; Roksandic, Mirjana; Cook, Gordon T.; Higham, Thomas; Pickard, Catriona

    2008-01-01

    Previous attempts to establish a chronology for Lepenski Vir using three different methods (stratigraphy, radiometric 14C dating of bulk charcoal samples, and AMS 14C dating of human bone collagen) produced inconsistent results. Discrepancies between the human bone and charcoal ages were found to result from a reservoir effect in the bones of people who ate significant quantities of Danube fish. When a reservoir ‘correction’ is applied, the human bone 14C dates are consistent with the charcoa...

  18. Dating the Italian Business Cycle: A Comparison of Procedures

    OpenAIRE

    Bruno Giancarlo; Edoardo Otranto

    2003-01-01

    The problem of dating the business cycle has recently received many contributions, with a lot of proposed statistical methodologies, parametric and non parametric. Despite of this, only a few countries produce an official dating of the business cycle. In this work we try to apply some procedures for an automatic dating of the Italian business cycle in the last thirty years, checking differences among various methodologies and with the ISAE chronology. To this end parametric as well as non par...

  19. Technology Corner: Dating of Electronic Hardware for Prior Art Investigations

    OpenAIRE

    Sellam Ismail

    2012-01-01

    In many legal matters, specifically patent litigation, determining and authenticating the date of computer hardware or other electronic products or components is often key to establishing the item as legitimate evidence of prior art. Such evidence can be used to buttress claims of technologies available or of events transpiring by or at a particular date.In 1945, the Electronics Industry Association published a standard, EIA 476-A, standardized in the reference Source and Date Code Marking (E...

  20. Online Dating Recommendations: Matching Markets and Learning Preferences

    OpenAIRE

    Tu, Kun; Ribeiro, Bruno; Jiang, Hua; Wang, Xiaodong; Jensen, David; Liu, Benyuan; Towsley, Don

    2014-01-01

    Recommendation systems for online dating have recently attracted much attention from the research community. In this paper we proposed a two-side matching framework for online dating recommendations and design an LDA model to learn the user preferences from the observed user messaging behavior and user profile features. Experimental results using data from a large online dating website shows that two-sided matching improves significantly the rate of successful matches by as much as 45%. Final...

  1. Luminescence dating: a guide for non-specialists

    Energy Technology Data Exchange (ETDEWEB)

    Aitken, M.J. (Oxford Univ. (UK). Research Lab. for Archaeology and the History of Art)

    1989-08-01

    The basic notions involved in the thermoluminescence (TL) dating of pottery are outlined as well as the technique's extension to other materials, e.g. burnt flint, unburnt calcite and unburnt sediment, and the use of the new technique of optical dating for the latter; this uses optically-stimulated luminescence (OSL). The rapid growth of activity in dating windblown and waterborne deposits of the last few hundred thousand years is noted. (author).

  2. Thermoluminescence dating of Zhuoshui Fan-delta, Yunlin, Taiwan

    International Nuclear Information System (INIS)

    Five samples, collected from different depth of one core drilled from Zhuoshui Fan-delta, Yunlin, Taiwan of China, were preliminarily tested by thermoluminescence dating. Ages of the sample younger than 50 ka are consistent with those from 14C dating method. This result indicates that the TL dating is a feasible method for the age determination of late Quaternary coastal sediments in Taiwan, China

  3. A Survey of Archaeological Samples Dated in 1984

    OpenAIRE

    Mejdahl, Vagn

    1985-01-01

    A survey is given of archaeological samples dated in 1984 at the Nordic Laboratory for Thermoluminescence Dating. A total of 79 samples were dated, 49 of which were burnt stones. All results were corrected for fading as measured for samples stored for four weeks at room temperature. The alpha dose contribution from uranium in the quartz and feldspar grains was included assuming an alpha efficiency factor of 0.1 for quartz and 0.2 for feldspars.

  4. Luminescence dating: a guide for non-specialists

    International Nuclear Information System (INIS)

    The basic notions involved in the thermoluminescence (TL) dating of pottery are outlined as well as the technique's extension to other materials, e.g. burnt flint, unburnt calcite and unburnt sediment, and the use of the new technique of optical dating for the latter; this uses optically-stimulated luminescence (OSL). The rapid growth of activity in dating windblown and waterborne deposits of the last few hundred thousand years is noted. (author)

  5. A survey of archaeological samples dated in 1984

    International Nuclear Information System (INIS)

    A survey is given of archaeological samples dated in 1984 at the Nordic Laboratory for Thermoluminescence Dating. A total of 79 samples were dated, 49 of which were burnt stones. All results were corrected for fading as measured for samples stored for four weeks at room temperature. The alpha dose contribution from uranium in the quartz and feldspar grains was included assuming an alpha efficiency facotr of 0.1 for quartz and 0.2 for feldspars. (author)

  6. New dating methods: The interior of matter reveals its age

    International Nuclear Information System (INIS)

    The author describes the various methods used for dating archeological material. The dating of ceramics and stone by thermoluminescence is explained, as is the use of the C14 dating method. The modification of the traditional C14 method by the use of mass spectrometry is described and the extension of this method with the use of a tandem Van der Graaff accelerator. (H.J.P.)

  7. Hydrodynamic aspects of carbon-14 groundwater dating

    International Nuclear Information System (INIS)

    The influence of man-made hydraulic disturbances on the 14C ages of groundwater from confined aquifers is examined, also taking into account 14C diffusion, which has an effect on 14C ages only if the hydrostatic pressure in the lower, confined aquifer is not more than 0.5m higher than that in the upper, unconfined aquifer. If the water head of the lower aquifer exceeds this value, the 14C ages of the confined groundwater are reliable. If the water head is lower, the 14C water ages rapidly approach values of a few thousand years, which no longer reflect the history of the groundwater regeneration. With regard to the palaeohydrogeological situation in Central Europe and the Central Sahara during the last 40,000 years, the 14C ages of Holocene groundwater, and the duration of the preceding hiatus of the groundwater regeneration during the last glacial period, can be determined reliably. 14C ages older than that are too small in many cases; thus, groundwater velocities derived from such data are too great. Recently operations were started to use the groundwater from confined aquifers associated with rates for lowering the water table at 0.1-0.5m/a that result in a rapid decrease in the 14C ages determined for these aquifers, delayed for one or two decades after the beginning of the withdrawal. The 3H level and the chemical content of the groundwater may also be changed after the same delay period. Changes of this kind can be used to estimate the hydraulic properties of the aquifer system. In conclusion, an interpretation of the 14C content of the groundwater from confined aquifers in terms of its age is only possible if the water head of the confined aquifer has not been lower than that of the upper aquifer for even a relatively short period. (author)

  8. Nutritional and functional properties of dates: a review.

    Science.gov (United States)

    Al-Farsi, Mohamed Ali; Lee, Chang Yong

    2008-11-01

    This review article provides information on the nutritional and functional constituents of dates (Phoenix dactylifera L.) and their seeds from over 80 references. Date flesh is found to be low in fat and protein but rich in sugars, mainly fructose and glucose. It is a high source of energy, as 100 g of flesh can provide an average of 314 kcal. Ten minerals were reported, the major being selenium, copper, potassium, and magnesium. The consumption of 100 g of dates can provide over 15% of the recommended daily allowance from these minerals. Vitamins B-complex and C are the major vitamins in dates. High in dietary fiber (8.0 g/100 g), insoluble dietary fiber was the major fraction of dietary fiber in dates. Dates are a good source of antioxidants, mainly carotenoids and phenolics. Date seeds contain higher protein (5.1 g/100 g) and fat (9.0 g/100 g) as compared to the flesh. It is also high in dietary fiber (73.1 g/100 g), phenolics (3942 mg/100 g) and antioxidants (80400 micromol/100 g). This detailed information on nutritional and health promoting components of dates and their seeds will enhance our knowledge and appreciation for the use of dates in our daily diet and their seeds as a functional food ingredient. PMID:18949591

  9. Assessment of the lower ESR dating range in Greek speleothems

    International Nuclear Information System (INIS)

    Pilot ESR dating studies on geologically young calcitic sinters were carried out, aiming at assessment of the lower ESR dating range in characteristic Greek speleoenvironments. Five stalactites were dated, coming from an ancient mining gallery, idle for the last 2,500 years, found on Siphnos island (Aegean). The calculated ages range between 1,7-2,0 ka. Medium to low measured external dose rates (aprox. 900 μGy/a) and very low measured radioelement concentration in samples are very usual in the Mediterranean environments. The study concludes that ESR dating of speleothems younger than two millenia is practically unattainable. Some geoarchaeological implications of the obtained ages are discussed. (author)

  10. Effects of light exposure on the TL dating of pottery

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Bleaching experiments on Chinese pottery fine grains were conducted under sunlight and laboratory light conditions. It is found that the thermoluminescence (TL) at high temperatures can be bleached significantly, but no effects were observed on TL signals used for the pre-dose dating technique. It is concluded that the pre-dose dating technique can be applied to samples even after light exposures. Pottery samples of Tang Dynasty and New Stone Age were studied. Modifications to routine pre-dose dating technique are proposed with adding preheat procedures and using saturation exponential fitting for the sensitivity change data. The modified technique can extend the dating range to New Stone Age.

  11. TL-dating of archaeological samples from Carnuntum

    International Nuclear Information System (INIS)

    A dating project was carried out aimed at optimizing the standard thermoluminescence (TL) procedure for pottery samples from Carnuntum, Austria. More than 70 samples of different types of pottery were analysed using the fine-grain technique. The environmental dose-rate at the excavation site was measured by different methods and a test programme with archaeologically well-dated samples was used to find the best procedure for dating. Bricks from a bath, a lime-kiln and pieces of pottery from the fill of a post hole were dated to an accuracy ranging from ± 3 to ± 14%. (author)

  12. Adsorption of triton X100 and potassium hydrogen phthalate on granular activated carbon from date pits

    Energy Technology Data Exchange (ETDEWEB)

    Merzougui, Z.; Nedjah, S.; Azoudj, Y.; Addoun, F. [Laboratoire d' etude physic-chimique des materiaux et application a l' environnement, Faculte de Chimie, USTHB (Algeria)], E-mail: zmerzougi@yahoo.fr

    2011-07-01

    Activated carbons, thanks to their versatility, are being used in the water treatment sector to absorb pollutants. Several factors influence the adsorption capacity of activated carbon and the aim of this study was to assess the effects of the porous texture and chemical nature of activated carbons on the adsorption of triton X100 and potassium hydrogen phthalate. Activated carbons used in this study were prepared from date pits with ZnCl2, KOH and H3PO4 by carbonization without adjuvant and adsorption of triton X100 and potassium hydrogen phthalate was conducted at 298K. Results showed that activated carbons prepared from date pits have a great potential for removing organic and inorganic pollutants from water and that the adsorption potential depends on the degree of activation of the activated carbons and on the compounds to absorb. This study highlighted that an increase of the carbon surface area and porosity results in a better adsorption capacity.

  13. NUTRITIONAL PRELIMINARY CHARACTERIZATION OF SOME VARIETIES OF DATES AND PALM DOWNGRADED AS RUMINANT FEED

    Directory of Open Access Journals (Sweden)

    H. SELMI

    2011-03-01

    Full Text Available In Saharan regions, the date palm which forms the backbone of agriculture, offers a wide range of agricultural by-products, traditionally used for domestic purposes. The determination of chemical composition and nutritional value of these byproducts for rational use in feeding livestock is needed. The analysis showed that the byproducts of palm have total nitrogen content (CP, lipid (FAT and (CB, NDF, ADF and ADL also with a higher nutritional value close to that of straw and hay. The scrap value of dates offers a relatively high energy (0.87 UFL / kg DM which is comparable to the concentrate feed but with relatively low levels of nitrogen or the need for supplementation or nitrogen treatment.

  14. The potential of using date palm fibres as reinforcement for polymeric composites

    International Nuclear Information System (INIS)

    Highlights: ► High concentration of chemical treatment may deteriorate the natural fibre strength. ► Fibre length in the composite significantly influences the interfacial adhesion property. ► 6% NaOH treatment is the optimum concentration to treat the natural fibres. ► Chemical treatment enhances the surface characteristics of the fibres. ► Chemical treatment reduces the porosity of the composites. -- Abstract: Interfacial adhesion of natural fibres as reinforcement for fibre polymeric composites is the key parameter in designing composites. In the current study, interfacial adhesion of date palm fibre with epoxy matrix is experimentally investigated using single fibre pull out technique. The influence of NaOH treatment concentrations (0–9%), fibre embedded length and fibre diameter on the interfacial adhesion property was considered in this study. Scanning Electron Microscopy (SEM) was used to observe the surface morphology and damage feature on the fibre and bonding area before and after conducting the experiments. The results revealed that 6% concentration of NaOH is the optimum solution for treating the date palm fibre to maintain high interfacial adhesion and strength with epoxy matrix. The embedded length of the fibre controlled the interfacial adhesion property, where 10 mm embedded length was the optimum fibre length.

  15. Social Information Processing in Dating Conflicts: Reciprocal Relationships With Dating Aggression in a One-Year Prospective Study.

    Science.gov (United States)

    Calvete, Esther; Orue, Izaskun; Gamez-Guadix, Manuel; López de Arroyabe, Elena

    2016-04-01

    The aim of this study was to assess the reciprocal associations among social information processing (SIP) in dating conflicts and the perpetration of dating aggression. A first step involved the development of a measure (The Social Information Processing Questionnaire in Dating Conflicts, SIPQ-DC) to assess social information in scenarios of conflict with dating partners. A sample of 1,272 adolescents (653 girls, 619 boys; Mage = 14.74 years, SD = 1.21) completed measures of SIP and dating aggression perpetration in two different times, which were spaced 1 year apart. Confirmatory factor analyses provided support for a model with five correlated factors for the SIPQ-DC, namely, hostile attribution, anger, aggressive response access, anticipation of positive consequences for oneself, and anticipation of negative consequences for partners. Although the perpetration of dating aggression at T1 was cross-sectionally associated with all the SIP components, anger was the only component that predicted the residual increase in dating aggression behavior over time. The perpetration of dating aggression predicted a worsening of cognitive-emotional processes involved in dating conflicts. Some longitudinal paths were significant only in male adolescents. In conclussion, relationships among SIP and aggression are reciprocal. Gender differences in longitudinal paths can contribute to explaining men's higher perpetration of violence in adulthood. PMID:25524267

  16. OSL versus 14C dating of sandy pedosediments as paleo-ecological archives in cultural landscapes

    Science.gov (United States)

    van Mourik, J. M.

    2009-04-01

    Late glacial aeolian coversand dominates the surface geology of an extensive area in Northwest Europe. During prehistoric and early historic time, forest grazing, wood cutting and shifting cultivation gradually transformed natural forest into heath land. Subsequently the use of the heath for the production of organic manure during the period of plaggen agriculture (from early Middle Ages to the invention of chemical fertilizers around 1900 AD) resulted in the comeback of active sand drifting. Locally the coversand landscape transformed into a driftsand landscape with characteristic new landforms and soils. Important parts of soil archives in these cultural landscapes are fimic covers, records of a long period of agricultural history and polycyclic driftsand deposits, records of alternating instable and stable phases in landscape development. Based on pollen analysis of fimic covers and buried humic soil horizons in polycyclic driftsand sequences, a lot of paleoecological information is available to reconstruct the development of soils and landforms in cultural landscapes, but we need a correct chronological framework to correlate information of various sources and sites. Traditionally 14C dating was applied on humic horizons of buried soils and a 14C based chronological framework was designed to estimate the accumulation rate of fimic covers and to date stable and instable periods in polycyclic driftsand profiles. However, 14C dates of extracted SOM (soil organic matter) are not always reliable. Firstly, in studies of fimic antrosols arose disagreement between paleoecological and historical interpretators of the evolution of these antrosols. The results of soil micromorphology and 14C dating, applied on separated SOM fractions (humine, humic acids and fulvic acids) showed that SOM, present in fimic horizons, consists of a complex mix of compounds of different ages and sources. Secondly, 14C dates of buried humic soil horizons are not always reliable. In thin

  17. Dating and Sex among Emerging Adults in Nepal

    Science.gov (United States)

    Regmi, Pramod R.; van Teijlingen, Edwin R.; Simkhada, Padam; Acharya, Dev R.

    2011-01-01

    Social and cultural changes in Nepal, including better communication facilities and transport, more urbanization and a rising age at which people marry, have created more opportunities for young people for "dating." Our qualitative study explores whether the existence of dating cultures influences young people's sexual behavior in Nepal. Focus…

  18. Dating Violence and Girls in the Juvenile Justice System

    Science.gov (United States)

    Kelly, Patricia J.; Cheng, An-Lin; Peralez-Dieckmann, Esther; Martinez, Elisabeth

    2009-01-01

    The purpose of this study is to explore the prevalence and associated behaviors of dating violence among a population of girls in the juvenile justice system. A sample of 590 girls from an urban juvenile justice system completed a questionnaire assessing attitudes and self-efficacy about and occurrence of dating violence. The analysis developed a…

  19. 5 CFR 844.301 - Commencing date of disability annuity.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Commencing date of disability annuity... SERVICE REGULATIONS (CONTINUED) FEDERAL EMPLOYEES' RETIREMENT SYSTEM-DISABILITY RETIREMENT Computation of Disability Annuity § 844.301 Commencing date of disability annuity. A disability annuity under this...

  20. Dating, sexual activity, and well-being in Italian adolescents

    NARCIS (Netherlands)

    Ciairano, S; Bonino, S; Kliewer, W; Miceli, R; Jackson, S

    2006-01-01

    Associations among dating, sexual activity, gender and adjustment were investigated in 2,2 73 Italian adolescents (54% female, ages 14 to 19 years) attending public high schools. After controlling for age and type of school attended, both being in a dating relationship and being male were associated

  1. 7 CFR 52.1003 - Grades of dates.

    Science.gov (United States)

    2010-01-01

    ... dates. (a) U.S. Grade A or U.S. Fancy is the quality of whole or pitted dates that are of one variety, that possess a good color, that are practically uniform in size, that are practically free from defects, that possess a good character, and that score not less than 90 points when scored in accordance...

  2. 17 CFR 230.459 - Calculation of effective date.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Calculation of effective date. 230.459 Section 230.459 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION GENERAL RULES AND REGULATIONS, SECURITIES ACT OF 1933 Filings; Fees; Effective Date § 230.459 Calculation...

  3. Dating violence experiences of lesbian, gay, bisexual, and transgender youth.

    Science.gov (United States)

    Dank, Meredith; Lachman, Pamela; Zweig, Janine M; Yahner, Jennifer

    2014-05-01

    Media attention and the literature on lesbian, gay, and bisexual youth overwhelmingly focus on violence involving hate crimes and bullying, while ignoring the fact that vulnerable youth also may be at increased risk of violence in their dating relationships. In this study, we examine physical, psychological, sexual, and cyber dating violence experiences among lesbian, gay, and bisexual youth--as compared to those of heterosexual youth, and we explore variations in the likelihood of help-seeking behavior and the presence of particular risk factors among both types of dating violence victims. A total of 5,647 youth (51 % female, 74 % White) from 10 schools participated in a cross-sectional anonymous survey, of which 3,745 reported currently being in a dating relationship or having been in one during the prior year. Results indicated that lesbian, gay, and bisexual youth are at higher risk for all types of dating violence victimization (and nearly all types of dating violence perpetration), compared to heterosexual youth. Further, when looking at gender identity, transgender and female youth are at highest risk of most types of victimization, and are the most likely perpetrators of all forms of dating violence but sexual coercion, which begs further exploration. The findings support the development of dating violence prevention programs that specifically target the needs and vulnerabilities of lesbian, gay, and bisexual youth, in addition to those of female and transgender youth. PMID:23861097

  4. Dating Violence: Youth at Risk. The Family Forum Library.

    Science.gov (United States)

    Sculli, Joan G.

    Dating violence can be described as a pattern of repeated threats or acts of physical, sexual, or emotional abuse by a member of an unmarried, noncohabitating couple. Dating violence is most often a pattern of behavior that begins with verbal and emotional abuse and eventually escalates into physical battering. Teens are particularly at risk…

  5. Dating Violence and Substance Use among Ethnically Diverse Adolescents

    Science.gov (United States)

    Temple, Jeff R.; Freeman, Daniel H., Jr.

    2011-01-01

    Teen dating violence is a serious public health concern with numerous and long-lasting consequences. Although alcohol and drug use have been associated with dating violence, little is known about the role of specific substances, especially the use of club drugs and the nonmedical use of prescription drugs. Thus, the authors examined the…

  6. Premarital Sex: Attitudes and Behavior by Dating Stage.

    Science.gov (United States)

    Roche, John P.

    1986-01-01

    Investigated differences between what people believe is proper premarital sexual behavior, what they do and what they think others are doing at five stages of dating. Results indicated persons are more restrictive in beliefs, more permissive in behavior, and most permissive in perceptions of others. During the early stages of dating, males and…

  7. 7 CFR 987.112 - Identification of dates.

    Science.gov (United States)

    2010-01-01

    ... IN RIVERSIDE COUNTY, CALIFORNIA Administrative Rules Identification and Outlet Specifications § 987... paragraphs (b) and (c), respectively, of this section, may be exported without change of marking. (e) Product... subcontainers) of Product dates, or Utility dates when approved for use in products, with the lot number and,...

  8. Date and Acquaintance Rape: Perceptions and Attitude Change Strategies.

    Science.gov (United States)

    Harrison, Patrick J.; And Others

    1991-01-01

    Investigated the dimensions of university students' (n=96) attitudes toward date and acquaintance rape. Examined the effects of a program designed to change those attitudes. Found college men had substantially greater tendencies to blame the victim for date and acquaintance rape than did women. (Author/ABL)

  9. Sexual Coercion on Dates: It's Not Just Rape.

    Science.gov (United States)

    Waldner-Haugrud, Lisa

    1995-01-01

    Contends that sexual coercion while dating falls under the umbrella of school-related violence. Discusses acquaintance and date rape, a sexual coercion continuum, and coercion victims. Concludes with a discussion of six techniques to reduce risk of sexual coercion. (CFR)

  10. A Typology for Sexually Aggressive Males in Dating Relationships.

    Science.gov (United States)

    Skinner, Linda J.; And Others

    1995-01-01

    Delineates a typology for sexual aggressors involved in dating relationships. Sexual aggressors involved in "date" or "acquaintance" rape fall into two categories, each with three subtypes. Is designed to assist in the implementation of treatment and prevention programs and lead to a better understanding of the differential effects of sexual…

  11. Deviations in the Accumulated Dose For Archaeological Dating

    Science.gov (United States)

    Farias, T. M. B.; Gennari, R. F.; Santana, J. C. C.; Calarge, F.

    The archaeological dating by thermoluminescence (TL) method is obtained through the determination of the accumulative dose and the annual. In this work, an evaluation of two factors which can cause deviations in the accumulative dose in archaeological dating of sediments by TL method was carried out.

  12. 21 CFR 1312.16 - Cancellation of permit; expiration date.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Cancellation of permit; expiration date. 1312.16 Section 1312.16 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE IMPORTATION AND...; expiration date. (a) A permit may be canceled after being issued, at the request of the importer, provided...

  13. Separation of uranium in bone rest for their dating

    International Nuclear Information System (INIS)

    The uranium (U) and thorium (Th) recovery, as fundamental part of the 'uranium serie' technique is an alternative method for dating of bone rests in Mexico. That so is how it has been possible its application for dating geological material and in this research it has been determined the age of some mammoth samples from the basin of Mexico valley. (Author)

  14. 16 CFR 1700.4 - Effective date of standards.

    Science.gov (United States)

    2010-01-01

    ... REGULATIONS POISON PREVENTION PACKAGING § 1700.4 Effective date of standards. (a) The FR document promulgating... shall apply. (b) Upon becoming effective, a child protection packaging standard shall apply only to... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Effective date of standards. 1700.4...

  15. 7 CFR 215.9 - Effective date for reimbursement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 4 2010-01-01 2010-01-01 false Effective date for reimbursement. 215.9 Section 215.9 Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE CHILD NUTRITION PROGRAMS SPECIAL MILK PROGRAM FOR CHILDREN § 215.9 Effective date for reimbursement. (a) A State Agency,...

  16. On the possible role of macrofungi in the biogeochemical fate of uranium in polluted forest soils

    International Nuclear Information System (INIS)

    Highlights: • Uranium is not accumulated in ectomycorrhizal and saprotrophic macrofungi. • Uranium is not accumulated in ectomycorrhizal roots of Picea abies. • Accumulation of metals in macrofungi does not depend on their fractionation in soils. - Abstract: Interactions of macrofungi with U, Th, Pb and Ag were investigated in the former ore mining district of Příbram, Czech Republic. Samples of saprotrophic (34 samples, 24 species) and ectomycorrhizal (38 samples, 26 species) macrofungi were collected from a U-polluted Norway spruce plantation and tailings and analyzed for metal content. In contrast to Ag, which was highly accumulated in fruit-bodies, concentrations of U generally did not exceed 3 mg/kg which indicates a very low uptake rate and efficient exclusion of U from macrofungi. In ectomycorrhizal tips (mostly determined to species level by DNA sequencing), U contents were practically identical with those of the non-mycorrhizal fine spruce roots. These findings suggest a very limited role of macrofungi in uptake and biotransformation of U in polluted forest soils. Furthermore, accumulation of U, Th, Pb and Ag in macrofungal fruit-bodies apparently does not depend on total content and chemical fractionation of these metals in soils (tested by the BCR sequential extraction in this study)

  17. On the possible role of macrofungi in the biogeochemical fate of uranium in polluted forest soils

    Energy Technology Data Exchange (ETDEWEB)

    Kubrová, Jaroslava [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University, Albertov 6, CZ-12843 Prague 2 (Czech Republic); Nuclear Physics Institute, v.v.i., Academy of Sciences of the Czech Republic, Husinec–Řež 130, CZ-25068 Řež near Prague (Czech Republic); Žigová, Anna [Institute of Geology, v.v.i., Academy of Sciences of the Czech Republic, Rozvojová 269, CZ-16500 Prague 6 (Czech Republic); Řanda, Zdeněk [Nuclear Physics Institute, v.v.i., Academy of Sciences of the Czech Republic, Husinec–Řež 130, CZ-25068 Řež near Prague (Czech Republic); Rohovec, Jan [Institute of Geology, v.v.i., Academy of Sciences of the Czech Republic, Rozvojová 269, CZ-16500 Prague 6 (Czech Republic); Gryndler, Milan [Institute of Microbiology, v.v.i., Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ-142 20 Prague 4 (Czech Republic); Krausová, Ivana [Nuclear Physics Institute, v.v.i., Academy of Sciences of the Czech Republic, Husinec–Řež 130, CZ-25068 Řež near Prague (Czech Republic); Dunn, Colin E. [8756 Pender Park Drive, Sidney, BC, V8L 3Z5 Canada (Canada); Kotrba, Pavel [Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague, Technická 3, CZ-166 28 Prague 6 (Czech Republic); and others

    2014-09-15

    Highlights: • Uranium is not accumulated in ectomycorrhizal and saprotrophic macrofungi. • Uranium is not accumulated in ectomycorrhizal roots of Picea abies. • Accumulation of metals in macrofungi does not depend on their fractionation in soils. - Abstract: Interactions of macrofungi with U, Th, Pb and Ag were investigated in the former ore mining district of Příbram, Czech Republic. Samples of saprotrophic (34 samples, 24 species) and ectomycorrhizal (38 samples, 26 species) macrofungi were collected from a U-polluted Norway spruce plantation and tailings and analyzed for metal content. In contrast to Ag, which was highly accumulated in fruit-bodies, concentrations of U generally did not exceed 3 mg/kg which indicates a very low uptake rate and efficient exclusion of U from macrofungi. In ectomycorrhizal tips (mostly determined to species level by DNA sequencing), U contents were practically identical with those of the non-mycorrhizal fine spruce roots. These findings suggest a very limited role of macrofungi in uptake and biotransformation of U in polluted forest soils. Furthermore, accumulation of U, Th, Pb and Ag in macrofungal fruit-bodies apparently does not depend on total content and chemical fractionation of these metals in soils (tested by the BCR sequential extraction in this study)

  18. 76 FR 14970 - National Starch and Chemical Company, Salisbury, Rowan County, NC; Notice of Settlement

    Science.gov (United States)

    2011-03-18

    ... AGENCY National Starch and Chemical Company, Salisbury, Rowan County, NC; Notice of Settlement AGENCY... National Starch and Chemical Company Site located in Mobile, Mobile County, Alabama for publication. DATES..., identified by Docket ID No. EPA-RO4- SFUND-2011-0278 or Site name National Starch and Chemical...

  19. Physicochemical properties and antioxidant activity of Tunisian date palm (Phoenix dactylifera L.) oil as affected by different extraction methods

    OpenAIRE

    Wahid Herch; Habib Kallel; Sadok Boukhchina

    2014-01-01

    The chemical analysis of flesh and seed of date palm fruit (Kentichi) was evaluated. Carbohydrates were the predominant component in all studied date cultivars (~78.69-83.46 g/100g dry matter), followed by moisture content (~9.23-11.17%), along with moderate amount of fat (~0.56-7.10 g/100g dry matter), protein (~2.16-2.80 g/100g dry matter), and ash (~1.18-1.64 g/100 g dry matter). Some antioxidants (Ascorbic acid, total phenolic, total flavonoid, chlorophyll and carotenoids) were found in d...

  20. The history of anthropogenic heavy metal input into North German lakes obtained from gammaspectrometrically dated sediment cores

    International Nuclear Information System (INIS)

    A simple freezing technique allows the recovery of undisturbed sediment cores from the topmost meter of the sediment column together with the semi-liquid sediment water interface. The technique is shown to produce reproducible results. Sediment cores from three lakes were radiometrically dated and analysed for their heavy metal contents. The activities of 134Cs (Chernobyl fallout), 137Cs (Chernobyl and bomb fallout), 241Am (bomb fallout), 214Pb, 214Bi and 210Pb (210Pbexc dating) were measured using gamma spectrometry on freeze-dried samples. Chemical analysis and stable lead isotope ratio analysis were carried out on completely dissolved samples using high resolution ICP-MS