Science.gov

Sample records for absolute dating methods

  1. Geomorphological Dating Using an Improved Scarp Degradation Model: Is This a Reliable Approach Compared With Common Absolute Dating Methods?

    NASA Astrophysics Data System (ADS)

    Oemisch, M.; Hergarten, S.; Neugebauer, H. J.

    2002-12-01

    Geomorphological dating of a certain landform or geomorphological structure is based on the evolution of the landscape itself. In this context it is difficult to use common absolute dating techniques such as luminescence and radiocarbon dating because they require datable material which is often not available. Additionally these methods do not always date the time since the formation of these structures. For these reasons the application of geomorphological dating seems one reliable possibility to date certain geomorphological features. The aim of our work is to relate present-day shapes of fault scarps and terrace risers to their ages. The time span since scarp formation ceased is reflected by the stage of degradation as well as the rounding of the profile edges due to erosive processes. It is assumed that the average rate of downslope soil movement depends on the local slope angle and can be described in terms of a diffusion equation. On the basis of these assumptions we present a model to simulate the temporal development of scarp degradation by erosion. A diffusivity reflecting the effects of soil erosion, surface runoff and detachability of particles as well as present-day shapes of scarps are included in the model. As observations of present-day scarps suggest a higher diffusivity at the toe than at the head of a slope, we suggest a linear approach with increasing diffusivities in downslope direction. First results show a better match between simulated and observed profiles of the Upper Rhine Graben in comparison to models using a constant diffusivity. To date the scarps the model has to be calibrated. For this purpose we estimate diffusivities by fitting modelled profiles to observed ones of known age. Field data have been collected in the area around Bonn, Germany and in the Alps, Switzerland. It is a matter of current research to assess the quality of this dating technique and to compare the results and the applicability with some of the absolute dating

  2. The quest for an absolute chronology in human prehistory: anthropologists, chemists and the fluorine dating method in palaeoanthropology.

    PubMed

    Goodrum, Matthew R; Olson, Cora

    2009-03-01

    By the early twentieth century there was a growing need within palaeoanthropology and prehistoric archaeology to find a way of dating fossils and artefacts in order to know the age of specific specimens, but more importantly to establish an absolute chronology for human prehistory. The radiocarbon and potassium-argon dating methods revolutionized palaeoanthropology during the last half of the twentieth century. However, prior to the invention of these methods there were attempts to devise chemical means of dating fossil bone. Collaborations between Emile Rivière and Adolphe Carnot in the 1890s led to the development of the fluorine dating method, but it was not until the 1940s that this method was improved and widely implemented by Kenneth Oakley to resolve a number of problems in palaeoanthropology, including the Piltdown Man controversy. The invention of the fluorine dating method marked a significant advance in the quest for absolute dating in palaeoanthropology, but it also highlights interesting problems and issues relating to the ability of palaeoanthropologists and chemists to bring together different skills and bodies of knowledge in order successfully to develop and apply the fluorine dating method.

  3. Suggested terminology for Quaternary dating methods

    USGS Publications Warehouse

    Colman, Steven M.; Pierce, K.L.; Birkeland, P.W.

    1987-01-01

    Classification of Quaternary dating methods should be based on the level of quantitative information and the degree of confidence contained in the age estimates produced by the dating methods. We recommend the use of the terms numerical-age, calibrated-age, relative-age, and correlated-age to describe these levels. We also classify dating methods by type into sideral, isotopic, radiogenic, chemical and biological, geomorphic, and correlation methods. The use of "absolute" is inappropriate for most dating methods, and should be replaced by "numerical." The use of "date" should be minimized in favor of "age" or "age estimate." We recommend use of the abbreviations ka and Ma for most ages; calender dates can be used where appropriate and yr B.P. can be used for radiocarbon ages. ?? 1987.

  4. Absolute dating and palaeoenvironmental evolution in Palaeolithic Mani, SW Peloponnesus

    NASA Astrophysics Data System (ADS)

    Christodoulakis, John; Bassiakos, Yannis; Athanassas, Constantin

    2013-04-01

    Data derived from palaeoenvironmental indicators are considered the most reliable in back casting former environmental contexts and also, where possible, in forecasting future trends in the environment. The peninsula of Mani, southern Peloponnesus, southwestern Greece, is a challenging area for studying past environmental changes of the Upper Quaternary, because of its nodal position between three continents, its long and multifarious coastal zone, as well as its active local tectonic regime. A great deal of sea level oscillations and palaeoclimatic and palaeoanthropological evidence have been well-documented in the terrestrial and coastal sedimentery deposits of the peninsula, particularly for the later part of the Quaternary (Kelletat und Gassert, 1975, Imperatori, 1966). That evidence mostly comes from paleoenvironmental indicators such as raised marine notches and marine terraces, as well as from other,indicators, and is frequently associated with sites of paleoanthropological significance An important parameter of those sedimentary deposits is their chronology. To date, the chronological framework of those processes is only loosely constrained. A first effort to produce chronological data for this area was made about twenty years ago by applying electron spin resonance (ESR) dating to speleothems from the local subsurface caverns system and other karst formations. Here, by engaging luminescence dating, we aimed to further control former ESR chronology as well as to extend numeric dating on sedimentary formations previously non-datable through ESR alone (i.e. fluvial/deltaic sediments occurring in the area as well as anthropogenic composite deposits usually including burnt bones and fragments of stone tools). Specifically, optically stimulated luminescence (OSL) dating, combined with the single-aliquot regenerative dose (SAR) protocol, produced a number of ages that are in fair agreement with the previous ESR chronology. Current data allowed us to comprehend

  5. Absolute method of measuring magnetic susceptibility

    USGS Publications Warehouse

    Thorpe, A.; Senftle, F.E.

    1959-01-01

    An absolute method of standardization and measurement of the magnetic susceptibility of small samples is presented which can be applied to most techniques based on the Faraday method. The fact that the susceptibility is a function of the area under the curve of sample displacement versus distance of the magnet from the sample, offers a simple method of measuring the susceptibility without recourse to a standard sample. Typical results on a few substances are compared with reported values, and an error of less than 2% can be achieved. ?? 1959 The American Institute of Physics.

  6. An absolute chronology for early Egypt using radiocarbon dating and Bayesian statistical modelling.

    PubMed

    Dee, Michael; Wengrow, David; Shortland, Andrew; Stevenson, Alice; Brock, Fiona; Girdland Flink, Linus; Bronk Ramsey, Christopher

    2013-11-08

    The Egyptian state was formed prior to the existence of verifiable historical records. Conventional dates for its formation are based on the relative ordering of artefacts. This approach is no longer considered sufficient for cogent historical analysis. Here, we produce an absolute chronology for Early Egypt by combining radiocarbon and archaeological evidence within a Bayesian paradigm. Our data cover the full trajectory of Egyptian state formation and indicate that the process occurred more rapidly than previously thought. We provide a timeline for the First Dynasty of Egypt of generational-scale resolution that concurs with prevailing archaeological analysis and produce a chronometric date for the foundation of Egypt that distinguishes between historical estimates.

  7. Absolute dating of Caribbean cores p6304-8 and p6304-9.

    PubMed

    Rona, E; Emiliani, C

    1969-01-03

    Two deep-sea cores from the central Caribbean have been dated by the thorium-230/ protactinium-231 method. The ages obtained are in agreement with the ages previously obtained from other deep-sea cores from the same area. Because of their greater precision, the new dates provide a more accurate time scale for the past 170,000 years.

  8. The Multispecimen Method for Absolute Paleointensity Determination

    NASA Astrophysics Data System (ADS)

    Dekkers, M. J.; de Groot, L. V.; Monster, M.

    2015-12-01

    Paleointensity methods have seen a large improvement in the 21th century. This included optimizing classic Thellier-style protocols along with establishing stringent sets of quality criteria, developing microwave excitation as an alternative to thermal treatment, selecting sample material that contains the most suitable remanence carriers (i.e. single domain magnetic particles), calibrating non-heating paleointensity methods, and the introduction of the multispecimen paleointensity (MSP) protocol. An MSP experiment is carried out at one specific temperature selected to avoid thermochemical alteration; a series of specimens is heated and cooled in various applied furnace fields oriented parallel to the specimen's NRM. The furnace field value at which no change in NRM occurs is the paleofield. While the rationale of the MSP approach is surprisingly straightforward, some of the original claims (Dekkers and Böhnel, 2006) are by now shown to be untenable. This pertains to the claimed domain state independence in the original MSP method, although the Fabian and Leonhardt (2010) extended protocol largely corrects for domain state effects. Here we describe the optimal workflow for MSP experiments derived from our collection of historic flows from four volcanic edifices: Mt. Etna, Hawaii, the Canary Islands, and the Azores. By comparing the experimental outcome derived from historic flows with known paleointensities we found that technically acceptable experiments may yield overestimates, correct determinations, as well as underestimates of the paleofield. The so-called "ARM test" (de Groot et al., 2012) can distinguish between those three options. Based on TRM and ARM being analogues, this test compares ARM acquisition curves of sister samples before and after heating to the MSP experiment temperature. Simulated paleointensity experiments following this workflow consistently deliver the correct answer (Monster et al., submitted).

  9. Absolute gain measurement by the image method under mismatched condition

    NASA Technical Reports Server (NTRS)

    Lee, Richard Q.; Baddour, Maurice F.

    1987-01-01

    Purcell's image method for measuring the absolute gain of an antenna is particularly attractive for small test antennas. The method is simple to use and utilizes only one antenna with a reflecting plane to provide an image for the receiving antenna. However, the method provides accurate results only if the antenna is matched to its waveguide. In this paper, a waveguide junction analysis is developed to determine the gain of an antenna under mismatched condition. Absolute gain measurements for two standard gain horn antennas have been carried out. Experimental results agree closely with published data.

  10. Non-Invasive Method of Determining Absolute Intracranial Pressure

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cantrell, John H., Jr. (Inventor); Hargens, Alan E. (Inventor)

    2004-01-01

    A method is presented for determining absolute intracranial pressure (ICP) in a patient. Skull expansion is monitored while changes in ICP are induced. The patient's blood pressure is measured when skull expansion is approximately zero. The measured blood pressure is indicative of a reference ICP value. Subsequently, the method causes a known change in ICP and measured the change in skull expansion associated therewith. The absolute ICP is a function of the reference ICP value, the known change in ICP and its associated change in skull expansion; and a measured change in skull expansion.

  11. Absolute Dating of Strath Terraces along the Western High Plains Reveals Complicated History of Occupation and Incision

    NASA Astrophysics Data System (ADS)

    Foster, M. A.; Anderson, R. S.; Gray, H. J.; Mahan, S.

    2015-12-01

    Gravel-capped strath terraces are preserved along the western High Plains, adjacent to the Colorado Front Range. Terrace elevations appear to connect across the landscape, representing previous levels of the Denver Basin during fluvial exhumation. In this tectonically quiescent region, climatically-driven fluctuations in sediment supply are often interpreted to drive terrace occupation and basin exhumation. We dated a series of strath terraces near Boulder, CO using 10Be/26Al cosmogenic radionuclides (CRNs) and optically stimulated luminescence. Results reveal: (1) a long history of fluvial occupation (0.5-1.0 Myr duration), with recent (<120 ka) fluvial abandonment of the highest surface; (2) a brief occupation of a narrow spillway, abandoned at 97.0 ± 4.2 ka, preserved because the stream was subsequently pirated; and (3) a long period of fluvial occupation of a lower terrace, recorded by the deposition of distinct gravel packages at 50-75 ka and 40.5 ± 5.0 ka. In conjunction with absolute dating on nearby terraces, our study indicates the system is more complex than originally thought. Ages are not consistent among terraces of similar elevations deposited by different stream systems. The link between terrace age and climate is not straightforward, as terraces can be occupied through several glacial-interglacial cycles. When a surface is abandoned, incision to the next level appears to occur quite rapidly through the soft Cretaceous shales. Long-term incision rates may be derived from elevations and ages of high preserved surfaces, but such incision rates reflect long periods of no vertical erosion punctuated with short periods of rapid incision. Such interpretations would not be possible without paired CRNs or combination with other geochronologic techniques. This study therefore represents a cautionary tale for the interpretation of tectonic or climatic processes and process rates from single-method dating of fluvial terraces.

  12. System and method for calibrating a rotary absolute position sensor

    NASA Technical Reports Server (NTRS)

    Davis, Donald R. (Inventor); Permenter, Frank Noble (Inventor); Radford, Nicolaus A (Inventor)

    2012-01-01

    A system includes a rotary device, a rotary absolute position (RAP) sensor generating encoded pairs of voltage signals describing positional data of the rotary device, a host machine, and an algorithm. The algorithm calculates calibration parameters usable to determine an absolute position of the rotary device using the encoded pairs, and is adapted for linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters. A method of calibrating the RAP sensor includes measuring the rotary position as encoded pairs of voltage signals, linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters, and calculating an absolute position of the rotary device using the calibration parameters. The calibration parameters include a positive definite matrix (A) and a center point (q) of the ellipse. The voltage signals may include an encoded sine and cosine of a rotary angle of the rotary device.

  13. Method and apparatus for two-dimensional absolute optical encoding

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B. (Inventor)

    2004-01-01

    This invention presents a two-dimensional absolute optical encoder and a method for determining position of an object in accordance with information from the encoder. The encoder of the present invention comprises a scale having a pattern being predetermined to indicate an absolute location on the scale, means for illuminating the scale, means for forming an image of the pattern; and detector means for outputting signals derived from the portion of the image of the pattern which lies within a field of view of the detector means, the field of view defining an image reference coordinate system, and analyzing means, receiving the signals from the detector means, for determining the absolute location of the object. There are two types of scale patterns presented in this invention: grid type and starfield type.

  14. Towards an absolute chronology for the Aegean iron age: new radiocarbon dates from Lefkandi, Kalapodi and Corinth.

    PubMed

    Toffolo, Michael B; Fantalkin, Alexander; Lemos, Irene S; Felsch, Rainer C S; Niemeier, Wolf-Dietrich; Sanders, Guy D R; Finkelstein, Israel; Boaretto, Elisabetta

    2013-01-01

    The relative chronology of the Aegean Iron Age is robust. It is based on minute stylistic changes in the Submycenaean, Protogeometric and Geometric styles and their sub-phases. Yet, the absolute chronology of the time-span between the final stages of Late Helladic IIIC in the late second millennium BCE and the archaic colonization of Italy and Sicily toward the end of the 8(th) century BCE lacks archaeological contexts that can be directly related to events carrying absolute dates mentioned in Egyptian/Near Eastern historical sources, or to well-dated Egyptian/Near Eastern rulers. The small number of radiocarbon dates available for this time span is not sufficient to establish an absolute chronological sequence. Here we present a new set of short-lived radiocarbon dates from the sites of Lefkandi, Kalapodi and Corinth in Greece. We focus on the crucial transition from the Submycenaean to the Protogeometric periods. This transition is placed in the late 11(th) century BCE according to the Conventional Aegean Chronology and in the late 12(th) century BCE according to the High Aegean Chronology. Our results place it in the second half of the 11(th) century BCE.

  15. Towards an Absolute Chronology for the Aegean Iron Age: New Radiocarbon Dates from Lefkandi, Kalapodi and Corinth

    PubMed Central

    Toffolo, Michael B.; Fantalkin, Alexander; Lemos, Irene S.; Felsch, Rainer C. S.; Niemeier, Wolf-Dietrich; Sanders, Guy D. R.; Finkelstein, Israel; Boaretto, Elisabetta

    2013-01-01

    The relative chronology of the Aegean Iron Age is robust. It is based on minute stylistic changes in the Submycenaean, Protogeometric and Geometric styles and their sub-phases. Yet, the absolute chronology of the time-span between the final stages of Late Helladic IIIC in the late second millennium BCE and the archaic colonization of Italy and Sicily toward the end of the 8th century BCE lacks archaeological contexts that can be directly related to events carrying absolute dates mentioned in Egyptian/Near Eastern historical sources, or to well-dated Egyptian/Near Eastern rulers. The small number of radiocarbon dates available for this time span is not sufficient to establish an absolute chronological sequence. Here we present a new set of short-lived radiocarbon dates from the sites of Lefkandi, Kalapodi and Corinth in Greece. We focus on the crucial transition from the Submycenaean to the Protogeometric periods. This transition is placed in the late 11th century BCE according to the Conventional Aegean Chronology and in the late 12th century BCE according to the High Aegean Chronology. Our results place it in the second half of the 11th century BCE. PMID:24386150

  16. Neutron activation analysis of certified samples by the absolute method

    NASA Astrophysics Data System (ADS)

    Kadem, F.; Belouadah, N.; Idiri, Z.

    2015-07-01

    The nuclear reactions analysis technique is mainly based on the relative method or the use of activation cross sections. In order to validate nuclear data for the calculated cross section evaluated from systematic studies, we used the neutron activation analysis technique (NAA) to determine the various constituent concentrations of certified samples for animal blood, milk and hay. In this analysis, the absolute method is used. The neutron activation technique involves irradiating the sample and subsequently performing a measurement of the activity of the sample. The fundamental equation of the activation connects several physical parameters including the cross section that is essential for the quantitative determination of the different elements composing the sample without resorting to the use of standard sample. Called the absolute method, it allows a measurement as accurate as the relative method. The results obtained by the absolute method showed that the values are as precise as the relative method requiring the use of standard sample for each element to be quantified.

  17. Progress Report of CNES Activities Regarding the Absolute Calibration Method

    DTIC Science & Technology

    2010-11-01

    several receivers (Ashtech Z12-T, Septentrio PolaRx2, and Dicom GTR50) and a GNSS signal simulator (Spirent 4760) according to the temperature and...laboratories, Ashtech Z12- T, Septentrio PolaRx2, and Dicom GTR50, can be calibrated with the absolute method [6,8]. The last works concerned the...Ashtech, Septentrio, and Dicom receiver calibrations. Table 2. Uncertainty of the different receiver calibrations. Uncertainty Source

  18. Estimating divergence dates and evaluating dating methods using phylogenomic and mitochondrial data in squamate reptiles.

    PubMed

    Mulcahy, Daniel G; Noonan, Brice P; Moss, Travis; Townsend, Ted M; Reeder, Tod W; Sites, Jack W; Wiens, John J

    2012-12-01

    Recently, phylogenetics has expanded to routinely include estimation of clade ages in addition to their relationships. Various dating methods have been used, but their relative performance remains understudied. Here, we generate and assemble an extensive phylogenomic data set for squamate reptiles (lizards and snakes) and evaluate two widely used dating methods, penalized likelihood in r8s (r8s-PL) and Bayesian estimation with uncorrelated relaxed rates among lineages (BEAST). We obtained sequence data from 25 nuclear loci (∼500-1,000 bp per gene; 19,020bp total) for 64 squamate species and nine outgroup taxa, estimated the phylogeny, and estimated divergence dates using 14 fossil calibrations. We then evaluated how well each method approximated these dates using random subsets of the nuclear loci (2, 5, 10, 15, and 20; replicated 10 times each), and using ∼1 kb of the mitochondrial ND2 gene. We find that estimates from r8s-PL based on 2, 5, or 10 loci can differ considerably from those based on 25 loci (mean absolute value of differences between 2-locus and 25-locus estimates were 9.0 Myr). Estimates from BEAST are somewhat more consistent given limited sampling of loci (mean absolute value of differences between 2 and 25-locus estimates were 5.0 Myr). Most strikingly, age estimates using r8s-PL for ND2 were ∼68-82 Myr older (mean=73.1) than those using 25 nuclear loci with r8s-PL. These results show that dates from r8s-PL with a limited number of loci (and especially mitochondrial data) can differ considerably from estimates derived from a large number of nuclear loci, whereas estimates from BEAST derived from fewer nuclear loci or mitochondrial data alone can be surprisingly similar to those from many nuclear loci. However, estimates from BEAST using relatively few loci and mitochondrial data could still show substantial deviations from the full data set (>50 Myr), suggesting the benefits of sampling many nuclear loci. Finally, we found that confidence

  19. Method of differential-phase/absolute-amplitude QAM

    DOEpatents

    Dimsdle, Jeffrey William

    2008-10-21

    A method of quadrature amplitude modulation involving encoding phase differentially and amplitude absolutely, allowing for a high data rate and spectral efficiency in data transmission and other communication applications, and allowing for amplitude scaling to facilitate data recovery; amplitude scale tracking to track-out rapid and severe scale variations and facilitate successful demodulation and data retrieval; 2.sup.N power carrier recovery; incoherent demodulation where coherent carrier recovery is not possible or practical due to signal degradation; coherent demodulation; multipath equalization to equalize frequency dependent multipath; and demodulation filtering.

  20. Method of differential-phase/absolute-amplitude QAM

    DOEpatents

    Dimsdle, Jeffrey William

    2007-07-03

    A method of quadrature amplitude modulation involving encoding phase differentially and amplitude absolutely, allowing for a high data rate and spectral efficiency in data transmission and other communication applications, and allowing for amplitude scaling to facilitate data recovery; amplitude scale tracking to track-out rapid and severe scale variations and facilitate successful demodulation and data retrieval; 2.sup.N power carrier recovery; incoherent demodulation where coherent carrier recovery is not possible or practical due to signal degradation; coherent demodulation; multipath equalization to equalize frequency dependent multipath; and demodulation filtering.

  1. Method of differential-phase/absolute-amplitude QAM

    DOEpatents

    Dimsdle, Jeffrey William

    2007-10-02

    A method of quadrature amplitude modulation involving encoding phase differentially and amplitude absolutely, allowing for a high data rate and spectral efficiency in data transmission and other communication applications, and allowing for amplitude scaling to facilitate data recovery; amplitude scale tracking to track-out rapid and severe scale variations and facilitate successful demodulation and data retrieval; 2.sup.N power carrier recovery; incoherent demodulation where coherent carrier recovery is not possible or practical due to signal degradation; coherent demodulation; multipath equalization to equalize frequency dependent multipath; and demodulation filtering.

  2. Method of differential-phase/absolute-amplitude QAM

    SciTech Connect

    Dimsdle, Jeffrey William

    2009-09-01

    A method of quadrature amplitude modulation involving encoding phase differentially and amplitude absolutely, allowing for a high data rate and spectral efficiency in data transmission and other communication applications, and allowing for amplitude scaling to facilitate data recovery; amplitude scale tracking to track-out rapid and severe scale variations and facilitate successful demodulation and data retrieval; 2.sup.N power carrier recovery; incoherent demodulation where coherent carrier recovery is not possible or practical due to signal degradation; coherent demodulation; multipath equalization to equalize frequency dependent multipath; and demodulation filtering.

  3. Method of differential-phase/absolute-amplitude QAM

    DOEpatents

    Dimsdle, Jeffrey William

    2007-07-17

    A method of quadrature amplitude modulation involving encoding phase differentially and amplitude absolutely, allowing for a high data rate and spectral efficiency in data transmission and other communication applications, and allowing for amplitude scaling to facilitate data recovery; amplitude scale tracking to track-out rapid and severe scale variations and facilitate successful demodulation and data retrieval; 2.sup.N power carrier recovery; incoherent demodulation where coherent carrier recovery is not possible or practical due to signal degradation; coherent demodulation; multipath equalization to equalize frequency dependent multipath; and demodulation filtering.

  4. Comparison of gestational dating methods and implications ...

    EPA Pesticide Factsheets

    OBJECTIVES: Estimating gestational age is usually based on date of last menstrual period (LMP) or clinical estimation (CE); both approaches introduce potential bias. Differences in methods of estimation may lead to misclassificat ion and inconsistencies in risk estimates, particularly if exposure assignment is also gestation-dependent. This paper examines a'what-if' scenario in which alternative methods are used and attempts to elucidate how method choice affects observed results.METHODS: We constructed two 20-week gestational age cohorts of pregnancies between 2000 and 2005 (New Jersey, Pennsylvania, Ohio, USA) using live birth certificates : one defined preterm birth (PTB) status using CE and one using LMP. Within these, we estimated risk for 4 categories of preterm birth (PTBs per 106 pregnancies) and risk differences (RD (95% Cl s)) associated with exposure to particulate matter (PM2. 5).RESULTS: More births were classified preterm using LMP (16%) compared with CE (8%). RD divergences increased between cohorts as exposure period approached delivery. Among births between 28 and 31 weeks, week 7 PM2.5 exposure conveyed RDs of 44 (21 to 67) for CE and 50 (18 to 82) for LMP populations, while week 24 exposure conveyed RDs of 33 (11 to 56) and -20 (-50 to 10), respectively.CONCLUSIONS: Different results from analyses restricted to births with both CE and LMP are most likely due to differences in dating methods rather than selection issues. Results are sensitive t

  5. Method and apparatus for making absolute range measurements

    DOEpatents

    Earl, Dennis D [Knoxville, TN; Allison, Stephen W [Knoxville, TN; Cates, Michael R [Oak Ridge, TN; Sanders, Alvin J [Knoxville, TN

    2002-09-24

    This invention relates to a method and apparatus for making absolute distance or ranging measurements using Fresnel diffraction. The invention employs a source of electromagnetic radiation having a known wavelength or wavelength distribution, which sends a beam of electromagnetic radiation through a screen at least partially opaque at the wavelength. The screen has an aperture sized so as to produce a Fresnel diffraction pattern. A portion of the beam travels through the aperture to a detector spaced some distance from the screen. The detector detects the central intensity of the beam as well as a set of intensities displaced from a center of the aperture. The distance from the source to the target can then be calculated based upon the known wavelength, aperture radius, and beam intensity.

  6. The absolute age of events in Earth and human history on the basis of radiocarbon dating

    NASA Astrophysics Data System (ADS)

    Pazdur, Anna

    2011-01-01

    Radiocarbon chronometry holds a special place among the many discoveries made in the field of applied nuclear research. Few discoveries in fact, even among those being honored with the Nobel Prize, have had such a powerful and lasting impact on the further development of science. This method, as well as many other complex research methods, which appear to constitute an independent scientific discipline, arose as a result of many years of work by a team of several scientists. However, the actual founder of radiocarbon chronometry was one man, Willard Frank Libby, honored for his contribution with the Nobel Prize in Chemistry in 1960. In Poland, the creative activity in this area was begun in the late 1940s by Włodzimierz Mościcki, who continued it in the last 10 years of his life in the Silesian University of Technology in Gliwice, where he founded the Gliwice Radiocarbon Laboratory.

  7. Weighted Wilcoxon-type Smoothly Clipped Absolute Deviation Method

    PubMed Central

    Wang, Lan; Li, Runze

    2009-01-01

    Summary Shrinkage-type variable selection procedures have recently seen increasing applications in biomedical research. However, their performance can be adversely influenced by outliers in either the response or the covariate space. This paper proposes a weighted Wilcoxon-type smoothly clipped absolute deviation (WW-SCAD) method, which deals with robust variable selection and robust estimation simultaneously. The new procedure can be conveniently implemented with the statistical software R. We establish that the WW-SCAD correctly identifies the set of zero coefficients with probability approaching one and estimates the nonzero coefficients with the rate n−1/2. Moreover, with appropriately chosen weights the WW-SCAD is robust with respect to outliers in both the x and y directions. The important special case with constant weights yields an oracle-type estimator with high efficiency at the presence of heavier-tailed random errors. The robustness of the WW-SCAD is partly justified by its asymptotic performance under local shrinking contamination. We propose a BIC-type tuning parameter selector for the WW-SCAD. The performance of the WW-SCAD is demonstrated via simulations and by an application to a study that investigates the effects of personal characteristics and dietary factors on plasma beta-carotene level. PMID:18647294

  8. Calibration method of absolute orientation of camera optical axis

    NASA Astrophysics Data System (ADS)

    Xu, Yong; Guo, Pengyu; Zhang, Xiaohu; Ding, Shaowen; Su, Ang; Li, Lichun

    2013-08-01

    Camera calibration is one of the most basic and important processes in optical measuring field. Generally, the objective of camera calibration is to estimate the internal and external parameters of object cameras, while the orientation error of optical axis is not included yet. Orientation error of optical axis is a important factor, which seriously affects measuring precision in high-precision measurement field, especially for those distant aerospace measurement in which object distance is much longer than focal length, that lead to magnifying the orientation errors to thousands times. In order to eliminate the influence of orientation error of camera optical axis, the imaging model of camera is analysed and established in this paper, and the calibration method is also introduced: Firstly, we analyse the reasons that cause optical axis error and its influence. Then, we find the model of optical axis orientation error and imaging model of camera basing on it's practical physical meaning. Furthermore, we derive the bundle adjustment algorithm which could compute the internal and external camera parameters and absolute orientation of camera optical axis simultaneously at high precision. In numeric simulation, we solve the camera parameters by using bundle adjustment optimization algorithm, then we correct the image points by calibration results according to the model of optical axis error, and the simulation result shows that our calibration model is reliable, effective and precise.

  9. Two methods for absolute calibration of dynamic pressure transducers

    NASA Astrophysics Data System (ADS)

    Swift, G. W.; Migliori, A.; Garrett, S. L.; Wheatley, J. C.

    1982-12-01

    Two techniques are described for absolute calibration of a dynamic pressure transducer from 0 to 400 Hz in 1-MPa helium gas. One technique is based on a comparison to a mercury manometer; the other is based on the principle of reciprocity. The two techniques agree within the instrumental uncertainties of 1%.

  10. Radioactive Dating: A Method for Geochronology.

    ERIC Educational Resources Information Center

    Rowe, M. W.

    1985-01-01

    Gives historical background on the discovery of natural radiation and discusses various techniques for using knowledge of radiochemistry in geochronological studies. Indicates that of these radioactive techniques, Potassium-40/Argon-40 dating is used most often. (JN)

  11. Single-track absolute position encoding method based on spatial frequency of stripes

    NASA Astrophysics Data System (ADS)

    Xiang, Xiansong; Lu, Yancong; Wei, Chunlong; Zhou, Changhe

    2014-11-01

    A new method of single-track absolute position encoding based on spatial frequency of stripes is proposed. Instead of using pseudorandom-sequence arranged stripes as in conventional situations, this kind of encoding method stores the location information in the frequency space of the stripes, which means the spatial frequency of stripes varies with position and indicates position. This encoding method has a strong fault-tolerant capability with single-stripe detecting errors. The method can be applied to absolute linear encoders, absolute photoelectric angle encoders or two-dimensional absolute linear encoders. The measuring apparatus includes a CCD image sensor and a microscope system, and the method of decoding this frequency code is based on FFT algorithm. This method should be highly interesting for practical applications as an absolute position encoding method.

  12. 29 CFR 4003.9 - Method and date of filing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Method and date of filing. 4003.9 Section 4003.9 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION GENERAL RULES FOR ADMINISTRATIVE REVIEW OF AGENCY DECISIONS General Provisions § 4003.9 Method and date of filing. (a) Method of filing. The PBGC applies the rules in...

  13. Methods to calibrate the absolute receive sensitivity of single-element, focused transducers.

    PubMed

    Rich, Kyle T; Mast, T Douglas

    2015-09-01

    Absolute pressure measurements of acoustic emissions by single-element, focused passive cavitation detectors would be facilitated by improved wideband receive calibration techniques. Here, calibration methods were developed to characterize the absolute, frequency-dependent receive sensitivity of a spherically focused, single-element transducer using pulse-echo and pitch-catch techniques. Validation of these calibration methods on a focused receiver were made by generating a pulse from a small diameter source at the focus of the transducer and comparing the absolute pressure measured by a calibrated hydrophone to that of the focused transducer using the receive sensitivities determined here.

  14. Combined use of relative and absolute dating techniques for detecting signals of Alpine landscape evolution during the late Pleistocene and early Holocene

    NASA Astrophysics Data System (ADS)

    Favilli, Filippo; Egli, Markus; Brandova, Dagmar; Ivy-Ochs, Susan; Kubik, Peter; Cherubini, Paolo; Mirabella, Aldo; Sartori, Giacomo; Giaccai, Daniele; Haeberli, Wilfried

    2009-11-01

    A combination of three relative and two absolute (numerical) dating techniques, applied on nine soil profiles in an Alpine environment located in Val di Rabbi (Trentino, Northern Italy), was used to improve the investigation methodology of Alpine sites in response to climate change and to reconstruct the chronology of late Pleistocene and early Holocene landscape evolution. The degree of podzolisation, clay mineral evolution and the element mass balances of each site were investigated. Furthermore, the stable fraction of the soil organic matter (SOM) was extracted with 10% H 2O 2 and 14C-dated. The age of the organic residues was compared with the age of charcoal fragments found in one of the studied soils and with the age of rock boulders obtained by surface exposure dating (SED) with cosmogenic 10Be. Numerical dating and weathering characteristics of the soils showed a fairly good agreement and enabled a relative and absolute differentiation of landscape elements. The combination of 14C-dating of SOM and SED indicated that deglaciation processes in Val di Rabbi were already far advanced by around 14 000 cal BP and that glacier oscillations affected the highest part of the region until about 9000 cal BP. The development of clay minerals is time-dependent and reflects weathering intensity. We found a close link between secondary clay minerals like smectite or vermiculite and soil age as obtained by the dating of the organic residues after the H 2O 2 treatment. Calculated element mass balances strongly correlated with the ages derived from 14C measurements. Old soils have lost a major part of base cations (up to 75% compared to the parent material), Fe and Al, which indicates a continuous high weathering intensity. Results of the chemical and mineralogical analyses were in good agreement with numerical dating techniques, showing the dynamics of an Alpine landscape within a relatively small area. The combination of relative and absolute dating techniques is a

  15. Analytical methods for dating modern writing instrument inks on paper.

    PubMed

    Ezcurra, Magdalena; Góngora, Juan M G; Maguregui, Itxaso; Alonso, Rosa

    2010-04-15

    This work reviews the different analytical methods that have been proposed in the field of forensic dating of inks from different modern writing instruments. The reported works have been classified according to the writing instrument studied and the ink component analyzed in relation to aging. The study, done chronologically, shows the advances experienced in the ink dating field in the last decades.

  16. A method to estimate the absolute ultrasonic nonlinearity parameter from relative measurements.

    PubMed

    Kim, Jongbeom; Song, Dong-Gi; Jhang, Kyung-Young

    2017-02-17

    The ultrasonic nonlinearity parameter, β, is determined from the displacement amplitude of the second-order harmonic frequency component generated during the propagation of ultrasonic waves through a material. This parameter is generally referred to as the absolute parameter. Meanwhile, it is difficult to measure the small displacement amplitude of the second-order harmonic component; therefore, most studies measure the relative parameter determined from the detected signal amplitude. However, for quantitative assessment of material degradation, the absolute parameter is still required. This study proposes a method to estimate the absolute parameter for damaged material by measuring the relative parameter. This method is based on the fact that the fractional ratio of the relative parameters between different materials is identical to that of the absolute parameters after compensation for material dependent differences such as the wavenumber and detection-sensitivity. In order to experimentally verify the method, the relative parameters of heat-treated Al6061-T6 alloy specimens with different aging times were measured to compare with absolute parameters directly measured by piezo-electric detection. The results show that the fluctuations of both parameters with respect to aging time were very similar to each other, and that the absolute parameters estimated by the proposed method were in good agreement with those measured directly.

  17. Age-dating of rockslides: Methods and limitations

    NASA Astrophysics Data System (ADS)

    Ostermann, M.; Sanders, D.; Prager, C.

    2009-04-01

    Age-dating of deposits of catastrophic rockslides is prerequisite to unravel the potential relation between the frequency of mass-wasting events with climatic change or earthquakes. In the Alps, about 250 rockslides exceeding 106 m3 in volume are known, but the age as yet is determined only for a comparatively small number of events. For age determination of rockslide events, different methods are available (e. g. Lang et al., 1999). Radiocarbon Dating In the past few decades, rockslide deposits commonly were proxy-dated by 14C age determination of organic remnants preserved (a) in glacial, fluvio-glacial sediments overridden by the rockslide, (b) within the rockslide mass, or (c) in rockslide-dammed backwater deposits or lakes situated atop the rockslide mass. In each case, the 14C age provides a different constraint on the age of the rockslide event: in case (a), the 14C age represents a maximum age of the event; in case (b), which is quite rare, the 14C age is generally considered as a good proxy of the event age; in case (c) the 14C age represents a minimum age for the rockslide event. Unfortunately, radiocarbon dating often cannot be applied because of absence of suited deposits or exposures thereof, lack of organic remnants or of remnants suited for age-dating, and/or because determined 14C ages are substantially biased. Optically Stimulated Luminescence (OSL) Proxy-dating of rockslide events by OSL can be applied to silt- to sand-sized quartzose sediments present (a) directly below, (b) within, or (c) above/laterally aside a rockslide mass. For each case (a) to (c), the determined ages are subject to the same constraints as outlined for radiocarbon dating. Unfortunately, situations allowing for application of OSL to rockslide event dating are comparatively rare, and the resulting ages tend to have a wide error range. Surface Exposure Dating with cosmogenic radionuclides Surface exposure ages can be determined for rock samples taken from the sliding planes at

  18. Re-creating Gauss's method for non-electrical absolute measurements of magnetic fields and moments

    NASA Astrophysics Data System (ADS)

    Van Baak, D. A.

    2013-10-01

    In 1832, Gauss made the first absolute measurements of magnetic fields and of magnetic moments in experiments that are straightforward and instructive to replicate. We show, using rare-earth permanent magnets and a variation of Gauss's technique, that the horizontal component of the ambient geomagnetic field, as well as the size of the magnetic moments of such magnets, can be found. The method shows the connection between the SI and cgs emu unit systems for these quantities and permits an absolute realization of the Ampere with considerable precision.

  19. Absolute age Determinations on Diamond by Radioisotopic Methods: NOT the way to Accurately Identify Diamond Provenance

    NASA Astrophysics Data System (ADS)

    Shirey, S. B.

    2002-05-01

    Gem-quality diamond contains such low abundances of parent-daughter radionuclides that dating the diamond lattice directly by isotopic measurements has been and will be impossible. Absolute ages on diamonds typically are obtained through measurements of their syngenetic mineral inclusions: Rb-Sr in garnet; Sm-Nd in garnet and pyroxene; Re-Os and U-Th-Pb in sulfide; K-Ar in pyroxene; and U-Pb in zircon. The application of the first two isotope schemes in the list requires putting together many inclusions from many diamonds whereas the latter isotope schemes permit ages on single diamonds. The key limitations on the application of these decay pairs are the availability and size of the inclusions, the abundance levels of the radionuclides, and instrumental sensitivity. Practical complications of radioisotope dating of inclusions are fatal to the application of the technique for diamond provenance. In all mines, the ratio of gem-quality diamonds to stones with datable inclusions is very high. Thus there is no way to date the valuable, marketable stones that are part of the conflict diamond problem, just their rare, flawed cousins. Each analysis destroys the diamond host plus the inclusion and can only be carried out in research labs by highly trained scientists. Thus, these methods can not be automated or applied to the bulk of diamond production. The geological problems with age dating are equally fatal to its application to diamond provenance. From the geological perspective, for age determination to work as a tool for diamond provenance studies, diamond ages would have to be specific to particular kimberlites or kimberlite fields and different between fields. The southern African Kaapvaal-Zimbabwe Craton and Limpopo Mobile Belt is the only cratonic region where age determinations have been applied on a large enough scale to a number of kimberlites to illustrate the geological problems in age measurements for diamond provenance. However, this southern African example

  20. A non-destructive method for dating human remains

    USGS Publications Warehouse

    Lail, Warren K.; Sammeth, David; Mahan, Shannon; Nevins, Jason

    2013-01-01

    The skeletal remains of several Native Americans were recovered in an eroded state from a creek bank in northeastern New Mexico. Subsequently stored in a nearby museum, the remains became lost for almost 36 years. In a recent effort to repatriate the remains, it was necessary to fit them into a cultural chronology in order to determine the appropriate tribe(s) for consultation pursuant to the Native American Grave Protection and Repatriation Act (NAGPRA). Because the remains were found in an eroded context with no artifacts or funerary objects, their age was unknown. Having been asked to avoid destructive dating methods such as radiocarbon dating, the authors used Optically Stimulated Luminescence (OSL) to date the sediments embedded in the cranium. The OSL analyses yielded reliable dates between A.D. 1415 and A.D. 1495. Accordingly, we conclude that the remains were interred somewhat earlier than A.D. 1415, but no later than A.D. 1495. We believe the remains are from individuals ancestral to the Ute Mouache Band, which is now being contacted for repatriation efforts. Not only do our methods contribute to the immediate repatriation efforts, they provide archaeologists with a versatile, non-destructive, numerical dating method that can be used in many burial contexts.

  1. Relative and Absolute Error Control in a Finite-Difference Method Solution of Poisson's Equation

    ERIC Educational Resources Information Center

    Prentice, J. S. C.

    2012-01-01

    An algorithm for error control (absolute and relative) in the five-point finite-difference method applied to Poisson's equation is described. The algorithm is based on discretization of the domain of the problem by means of three rectilinear grids, each of different resolution. We discuss some hardware limitations associated with the algorithm,…

  2. A high-resolution, absolute-dated deglacial speleothem record of Indian Ocean climate from Socotra Island, Yemen

    NASA Astrophysics Data System (ADS)

    Shakun, Jeremy D.; Burns, Stephen J.; Fleitmann, Dominik; Kramers, Jan; Matter, Albert; Al-Subary, Abdulkarim

    2007-07-01

    Stalagmite M1-5 from Socotra Island, Yemen in the northwest Indian Ocean provides a robust, high-resolution paleoclimate record from ˜ 27.4-11.1 ka based on 717 stable isotope and 28 230Th measurements. Variations in M1-5 oxygen isotope ratios ( δ18O) are interpreted to be primarily driven by an amount effect related to changes in the mean position and/or intensity of convection of the intertropical convergence zone, the island's only source of precipitation. The M1-5 δ18O time series is strongly correlated to the Greenland ice cores, similar to an older Socotra speleothem deposited from 53-40 ka [S.J. Burns, D. Fleitmann, A. Matter, J. Kramers, A. Al-Subbary, Indian Ocean climate and an absolute chronology over Dansgaard/Oeschger events 9 to 13, Science 301 (2003) 1365-1367], indicating that a North Atlantic-Indian Ocean cold-dry/warm-wet teleconnection persisted through the end of the last glacial period. Peak aridification occurred at ˜ 23 ka and a gradual increase in moisture thereafter was interrupted by an abrupt drying event at ˜ 16.4 ka, perhaps related to Heinrich event 1. Indian Ocean rainfall increased dramatically during the Bølling period and then decreased continuously and gradually through the Allerød and Younger Dryas. The Holocene began abruptly with increased precipitation at 11.4 ka and was followed by a major but short-lived drying during the Preboreal Oscillation at ˜ 11.2 ka. M1-5 is highly correlated to the Dongge Cave record from 15.5-11 ka, suggesting much of the Indian Ocean monsoon region responded similarly to the major climate changes of the last deglaciation. The transitions into the Younger Dryas and to a lesser extent the Bølling are remarkably gradual in M1-5, as they are in all other Asian speleothem records, occurring over several centuries. These gradual transitions are in striking contrast to high-resolution records from around the North Atlantic basin where the transitions are extremely abrupt and generally occur in

  3. [Study on the absolute spectral irradiation calibration method for far ultraviolet spectrometer in remote sensing].

    PubMed

    Yu, Lei; Lin, Guan-Yu; Chen, Bin

    2013-01-01

    The present paper studied spectral irradiation responsivities calibration method which can be applied to the far ultraviolet spectrometer for upper atmosphere remote sensing. It is difficult to realize the calibration for far ultraviolet spectrometer for many reasons. Standard instruments for far ultraviolet waveband calibration are few, the degree of the vacuum experiment system is required to be high, the stabilities of the experiment are hardly maintained, and the limitation of the far ultraviolet waveband makes traditional diffuser and the integrating sphere radiance calibration method difficult to be used. To solve these problems, a new absolute spectral irradiance calibration method was studied, which can be applied to the far ultraviolet calibration. We build a corresponding special vacuum experiment system to verify the calibration method. The light source system consists of a calibrated deuterium lamp, a vacuum ultraviolet monochromater and a collimating system. We used the calibrated detector to obtain the irradiance responsivities of it. The three instruments compose the calibration irradiance source. We used the "calibration irradiance source" to illuminate the spectrometer prototype and obtained the spectral irradiance responsivities. It realized the absolute spectral irradiance calibration for the far ultraviolet spectrometer utilizing the calibrated detector. The absolute uncertainty of the calibration is 7.7%. The method is significant for the ground irradiation calibration of the far ultraviolet spectrometer in upper atmosphere remote sensing.

  4. Effect of the absolute statistic on gene-sampling gene-set analysis methods.

    PubMed

    Nam, Dougu

    2015-03-02

    Gene-set enrichment analysis and its modified versions have commonly been used for identifying altered functions or pathways in disease from microarray data. In particular, the simple gene-sampling gene-set analysis methods have been heavily used for datasets with only a few sample replicates. The biggest problem with this approach is the highly inflated false-positive rate. In this paper, the effect of absolute gene statistic on gene-sampling gene-set analysis methods is systematically investigated. Thus far, the absolute gene statistic has merely been regarded as a supplementary method for capturing the bidirectional changes in each gene set. Here, it is shown that incorporating the absolute gene statistic in gene-sampling gene-set analysis substantially reduces the false-positive rate and improves the overall discriminatory ability. Its effect was investigated by power, false-positive rate, and receiver operating curve for a number of simulated and real datasets. The performances of gene-set analysis methods in one-tailed (genome-wide association study) and two-tailed (gene expression data) tests were also compared and discussed.

  5. Verification of 235U mass content in nuclear fuel plates by an absolute method

    NASA Astrophysics Data System (ADS)

    El-Gammal, W.

    2007-01-01

    Nuclear Safeguards is referred to a verification System by which a State can control all nuclear materials (NM) and nuclear activities under its authority. An effective and efficient Safeguards System must include a system of measurements with capabilities sufficient to verify such NM. Measurements of NM using absolute methods could eliminate the dependency on NM Standards, which are necessary for other relative or semi-absolute methods. In this work, an absolute method has been investigated to verify the 235U mass content in nuclear fuel plates of Material Testing Reactor (MTR) type. The most intense gamma-ray signature at 185.7 keV emitted after α-decay of the 235U nuclei was employed in the method. The measuring system (an HPGe-spectrometer) was mathematically calibrated for efficiency using the general Monte Carlo transport code MCNP-4B. The calibration results and the measured net count rate were used to estimate the 235U mass content in fuel plates at different detector-to-fuel plate distances. Two sets of fuel plates, containing natural and low enriched uranium, were measured at the Fuel Fabrication Facility. Average accuracies for the estimated 235U masses of about 2.62% and 0.3% are obtained for the fuel plates containing natural and low enriched uranium; respectively, with a precision of about 3%.

  6. Measurements of absolute concentrations of NADH in cells using the phasor FLIM method.

    PubMed

    Ma, Ning; Digman, Michelle A; Malacrida, Leonel; Gratton, Enrico

    2016-07-01

    We propose a graphical method using the phasor representation of the fluorescence decay to derive the absolute concentration of NADH in cells. The method requires the measurement of a solution of NADH at a known concentration. The phasor representation of the fluorescence decay accounts for the differences in quantum yield of the free and bound form of NADH, pixel by pixel of an image. The concentration of NADH in every pixel in a cell is obtained after adding to each pixel in the phasor plot a given amount of unmodulated light which causes a shift of the phasor towards the origin by an amount that depends on the intensity at the pixel and the fluorescence lifetime at the pixel. The absolute concentration of NADH is obtained by comparison of the shift obtained at each pixel of an image with the shift of the calibrated solution.

  7. Measurements of absolute concentrations of NADH in cells using the phasor FLIM method

    PubMed Central

    Ma, Ning; Digman, Michelle A.; Malacrida, Leonel; Gratton, Enrico

    2016-01-01

    We propose a graphical method using the phasor representation of the fluorescence decay to derive the absolute concentration of NADH in cells. The method requires the measurement of a solution of NADH at a known concentration. The phasor representation of the fluorescence decay accounts for the differences in quantum yield of the free and bound form of NADH, pixel by pixel of an image. The concentration of NADH in every pixel in a cell is obtained after adding to each pixel in the phasor plot a given amount of unmodulated light which causes a shift of the phasor towards the origin by an amount that depends on the intensity at the pixel and the fluorescence lifetime at the pixel. The absolute concentration of NADH is obtained by comparison of the shift obtained at each pixel of an image with the shift of the calibrated solution. PMID:27446681

  8. 29 CFR 4207.11 - Method of filing; method and date of issuance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Method of filing; method and date of issuance. 4207.11 Section 4207.11 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION WITHDRAWAL LIABILITY FOR MULTIEMPLOYER PLANS REDUCTION OR WAIVER OF COMPLETE WITHDRAWAL LIABILITY § 4207.11 Method of filing; method and date of...

  9. A new method to calibrate the absolute sensitivity of a soft X-ray streak camera

    NASA Astrophysics Data System (ADS)

    Yu, Jian; Liu, Shenye; Li, Jin; Yang, Zhiwen; Chen, Ming; Guo, Luting; Yao, Li; Xiao, Shali

    2016-12-01

    In this paper, we introduce a new method to calibrate the absolute sensitivity of a soft X-ray streak camera (SXRSC). The calibrations are done in the static mode by using a small laser-produced X-ray source. A calibrated X-ray CCD is used as a secondary standard detector to monitor the X-ray source intensity. In addition, two sets of holographic flat-field grating spectrometers are chosen as the spectral discrimination systems of the SXRSC and the X-ray CCD. The absolute sensitivity of the SXRSC is obtained by comparing the signal counts of the SXRSC to the output counts of the X-ray CCD. Results show that the calibrated spectrum covers the range from 200 eV to 1040 eV. The change of the absolute sensitivity in the vicinity of the K-edge of the carbon can also be clearly seen. The experimental values agree with the calculated values to within 29% error. Compared with previous calibration methods, the proposed method has several advantages: a wide spectral range, high accuracy, and simple data processing. Our calibration results can be used to make quantitative X-ray flux measurements in laser fusion research.

  10. Position error correction in absolute surface measurement based on a multi-angle averaging method

    NASA Astrophysics Data System (ADS)

    Wang, Weibo; Wu, Biwei; Liu, Pengfei; Liu, Jian; Tan, Jiubin

    2017-04-01

    We present a method for position error correction in absolute surface measurement based on a multi-angle averaging method. Differences in shear rotation measurements at overlapping areas can be used to estimate the unknown relative position errors of the measurements. The model and the solving of the estimation algorithm have been discussed in detail. The estimation algorithm adopts a least-squares technique to eliminate azimuthal errors caused by rotation inaccuracy. The cost functions can be minimized to determine the true values of the unknowns of Zernike polynomial coefficients and rotation angle. Experimental results show the validity of the method proposed.

  11. MARQUIS: A Multiplex Method for Absolute Quantification of Peptides and Post-Translational Modifications

    PubMed Central

    Curran, Timothy G; Zhang, Yi; Ma, Daniel J.; Sarkaria, Jann N.; White, Forest M

    2014-01-01

    Absolute quantification of protein expression and post-translational modifications by mass spectrometry has been challenging due to a variety of factors, including the potentially large dynamic range of phosphorylation response. To address these issues, we have developed MARQUIS — Multiplex Absolute Regressed Quantification with Internal Standards — a novel mass spectrometry-based approach using a combination of isobaric tags and heavy-labeled standard peptides to construct internal standard curves for peptides derived from key nodes in signal transduction networks. We applied MARQUIS to quantify phosphorylation dynamics within the EGFR network at multiple time points following stimulation with several ligands, enabling a quantitative comparison of EGFR phosphorylation sites and demonstrating that receptor phosphorylation is qualitatively similar but quantitatively distinct for each EGFR ligand tested. MARQUIS was also applied to quantify the effect of EGFR kinase inhibition on glioblastoma patient derived xenografts. MARQUIS is a versatile method, broadly applicable and extendable to multiple mass spectrometric platforms. PMID:25581283

  12. Comparison of three digital fringe signal processing methods in a ballistic free-fall absolute gravimeter

    NASA Astrophysics Data System (ADS)

    Svitlov, S.; Masłyk, P.; Rothleitner, Ch; Hu, H.; Wang, L. J.

    2010-12-01

    This paper reports results of comparison of three digital fringe signal processing methods implemented in the same free-fall absolute gravimeter. A two-sample zero-crossing method, a windowed second-difference method and a method of non-linear least-squares adjustment on the undersampled fringe signal are compared in numerical simulations, hardware tests and actual measurements with the MPG-2 absolute gravimeter, developed at the Max Planck Institute for the Science of Light, Germany. The two-sample zero-crossing method realizes data location schemes that are both equally spaced in distance and equally spaced in time (EST) along the free-fall trajectory. The windowed second-difference method and the method of non-linear least-squares adjustment with complex heterodyne demodulation operate with the EST data. Results of the comparison verify an agreement of the three methods within one part in 109 of the measured gravity value, provided a common data location scheme is considered.

  13. Tests of a comparative method of dating plutonium samples

    NASA Astrophysics Data System (ADS)

    West, D.

    1987-04-01

    Tests of a comparative method of dating plutonium samples have been carried out using 241Pu in aqueous solution. The six samples were of known ages (between 0.25 and 15 yr) and with one exception the measured ages, using particular samples as standards, agreed with the stated ages. In one case the agreement was beter than 1% in age. Mixed-oxide fuel pins were also intercompared. In this case it was with some difficulty that a sample of known age was obtaine. Comparison using this sample and an older one gave the same value (within ±1%) for the separation date of the unknown sample on three occasions over a three year period.

  14. Dating Indian corals by U-decay-series methods

    NASA Astrophysics Data System (ADS)

    Somayajulu, B. L. K.; Broecker, W. S.; Goddard, J.

    1985-09-01

    Nine samples of corals collected from seven locations in the Saurashtra Coastal region of India were dated by 238U series disequilibrium methods. Of the three age groups (6000, 30,000, and 120,000 yr) reported for this region by the earlier studies of S. K. Gupta and B. S. Amin (1974, Marine Geology16, 79-83), we could confirm only the 6000-yr group. Instead of a 120,000-yr group, we found a scatter of ages between 118,000 and 176,000 yr. There appears to be no evidence for 30,000-yr-old corals from this region.

  15. Dirhodium complexes: determination of absolute configuration by the exciton chirality method using VCD spectroscopy.

    PubMed

    Szilvágyi, Gábor; Brém, Balázs; Báti, Gábor; Tölgyesi, László; Hollósi, Miklós; Vass, Elemér

    2013-09-28

    Inherently chiral dinuclear rhodium complexes have been synthesized from the well-known dirhodium(II)-acetate and chiral/achiral amino acids. These complexes have a twisted paddlewheel structure due to axial chirality. Chiral induction could be observed when the ligands were chiral, opposite to the case of achiral ligands, where a racemic mixture was formed. The racemic mixture was separated by chiral HPLC-ECD. The stereochemical properties of these complexes were determined by VCD spectroscopy supported by theoretical calculations at the DFT level. We present a simple route to determine the absolute configuration by an exciton chirality method using VCD spectroscopy.

  16. Easy Absolute Values? Absolutely

    ERIC Educational Resources Information Center

    Taylor, Sharon E.; Mittag, Kathleen Cage

    2015-01-01

    The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…

  17. Simple absolute quantification method correcting for quantitative PCR efficiency variations for microbial community samples.

    PubMed

    Brankatschk, Robert; Bodenhausen, Natacha; Zeyer, Josef; Bürgmann, Helmut

    2012-06-01

    Real-time quantitative PCR (qPCR) is a widely used technique in microbial community analysis, allowing the quantification of the number of target genes in a community sample. Currently, the standard-curve (SC) method of absolute quantification is widely employed for these kinds of analysis. However, the SC method assumes that the amplification efficiency (E) is the same for both the standard and the sample target template. We analyzed 19 bacterial strains and nine environmental samples in qPCR assays, targeting the nifH and 16S rRNA genes. The E values of the qPCRs differed significantly, depending on the template. This has major implications for the quantification. If the sample and standard differ in their E values, quantification errors of up to orders of magnitude are possible. To address this problem, we propose and test the one-point calibration (OPC) method for absolute quantification. The OPC method corrects for differences in E and was derived from the ΔΔC(T) method with correction for E, which is commonly used for relative quantification in gene expression studies. The SC and OPC methods were compared by quantifying artificial template mixtures from Geobacter sulfurreducens (DSM 12127) and Nostoc commune (Culture Collection of Algae and Protozoa [CCAP] 1453/33), which differ in their E values. While the SC method deviated from the expected nifH gene copy number by 3- to 5-fold, the OPC method quantified the template mixtures with high accuracy. Moreover, analyzing environmental samples, we show that even small differences in E between the standard and the sample can cause significant differences between the copy numbers calculated by the SC and the OPC methods.

  18. Teaching Absolute Value Meaningfully

    ERIC Educational Resources Information Center

    Wade, Angela

    2012-01-01

    What is the meaning of absolute value? And why do teachers teach students how to solve absolute value equations? Absolute value is a concept introduced in first-year algebra and then reinforced in later courses. Various authors have suggested instructional methods for teaching absolute value to high school students (Wei 2005; Stallings-Roberts…

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

    ERIC Educational Resources Information Center

    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)

  20. Absolute Geostrophic Velocity Inverted from World Ocean Atlas 2013 (WOAV13) with the P-Vector Method

    DTIC Science & Technology

    2015-11-01

    1 WOAV13: world ocean absolute geostrophic velocity Absolute Geostrophic Velocity Inverted from... World Ocean Atlas 2013 (WOAV13) with the P-Vector Method P. C. Chu* and C. W. Fan Naval Ocean Analysis and Prediction (NOAP) Laboratory...from World Ocean Atlas-2013 (WOA13) temperature and salinity fields using the P-vector method. It provides a climatological velocity field that is

  1. Comparison and applications of label-free absolute proteome quantification methods on Escherichia coli.

    PubMed

    Arike, L; Valgepea, K; Peil, L; Nahku, R; Adamberg, K; Vilu, R

    2012-09-18

    Three different label-free proteome quantification methods--APEX, emPAI and iBAQ--were evaluated to measure proteome-wide protein concentrations in the cell. All the methods were applied to a sample from Escherichia coli chemostat culture. A Pearson squared correlation of approximately 0.6 among the three quantification methods was demonstrated. Importantly, the sum of quantified proteins by iBAQ and emPAI corresponded with the Lowry total protein quantification, demonstrating applicability of label-free methods for an accurate calculation of protein concentrations at the proteome level. The iBAQ method showed the best correlation between biological replicates, a normal distribution among all protein abundances, and the lowest variation among ribosomal protein abundances, which are expected to have equal amounts. Absolute quantitative proteome data enabled us to evaluate metabolic cost for protein synthesis and apparent catalytic activities of enzymes by integration with flux analysis. All the methods demonstrated similar ATP costs for protein synthesis for different cellular processes and that costs for expressing biomass synthesis related proteins were higher than those for energy generation. Importantly, catalytic activities of energy metabolism enzymes were an order or two higher than those of monomer synthesis. Interestingly, a staircase-like protein expression was demonstrated for most of the transcription units.

  2. Free volume hypothetical scanning molecular dynamics method for the absolute free energy of liquids

    PubMed Central

    White, Ronald P.; Meirovitch, Hagai

    2006-01-01

    The hypothetical scanning (HS) method is a general approach for calculating the absolute entropy, S, and free energy, F, by analyzing Boltzmann samples obtained by Monte Carlo (MC) or molecular dynamics (MD) techniques. With HS applied to a fluid, each configuration i of the sample is reconstructed by gradually placing the molecules in their positions at i using transition probabilities (TPs). With our recent version of HS, called HSMC-EV, each TP is calculated from MC simulations, where the simulated particles are excluded from the volume reconstructed in previous steps. In this paper we remove the excluded volume (EV) restriction, replacing it by a “free volume” (FV) approach. For liquid argon, HSMC-FV leads to an improvement in efficiency over HSMC-EV by a factor of 2–3. Importantly, the FV treatment greatly simplifies the HS implementation for liquids, allowing a much more natural application of the method for MD simulations. Given the success and popularity of MD, the present development of the HSMD method for liquids is an important advancement for HS methodology. Results for the HSMD-FV approach presented here agree well with our HSMC and thermodynamic integration results. The efficiency of HSMD-FV is equivalent to HSMC-EV. The potential use of HSMC(MD)-FV in protein systems with explicit water is discussed. PMID:16774320

  3. The high-precision videometrics methods to determining absolute vertical benchmark

    NASA Astrophysics Data System (ADS)

    Liu, Jinbo; Zhu, Zhaokun

    2013-01-01

    The mobile measurement equipment plays an important role in engineering measurement tasks and its measuring device is fixed with the vehicle platform. Therefore, how to correct the measured error in time that caused by swayed platform is a basic problem. Videometrics has its inherent advantages in solving this problem. First of all, videometrics technology is non-contact measurement, which has no effect on the target's structural characteristics and motion characteristics. Secondly, videometrics technology has high precision especially for surface targets and linear targets in the field of view. Thirdly, videometrics technology has the advantages of automatic, real-time and dynamic. This paper is mainly for mobile theodolite.etc that works under the environment of absolute vertical benchmark and proposed two high-precision methods to determine vertical benchmark: Direct-Extracting, which is based on the intersection of plats under the help of two cameras; Benchmark-Transformation, which gets the vertical benchmark by reconstructing the level-plat. Two methods both have the precision of under 10 seconds by digital simulation and physical experiments. The methods proposed by this paper have significance both on the theory and application.

  4. 29 CFR 4208.10 - Method of filing; method and date of issuance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Method of filing; method and date of issuance. 4208.10 Section 4208.10 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION WITHDRAWAL LIABILITY FOR MULTIEMPLOYER PLANS REDUCTION OR WAIVER OF PARTIAL WITHDRAWAL LIABILITY §...

  5. Tsunakawa-Shaw method - an absolute paleointensity technique using alternating field demagnetization

    NASA Astrophysics Data System (ADS)

    Yamamoto, Y.; Mochizuki, N.; Shibuya, H.; Tsunakawa, H.

    2015-12-01

    Among geologic materials volcanic rocks have been typically used to deduce an absolute paleointensity. In the last decade, however, there seems a becoming consensus that volcanic rocks are not so ideal materials due to such as magnetic grains other than non-interacting single domain particles. One approach to obtain a good paleointensity estimate from the rocks is to reduce and correct the non-ideality, suppress alterations in laboratory and screen out suspicious results. We have been working on a development and an application of the Tsunakawa-Shaw method, which has been previously called the LTD-DHT Shaw method. This method is an AF(alternating field)-based technique and thus a paleointensity is estimated using coercivity spectra. To reduce the non-ideality, all remanences undergo low-temperature demagnetization (LTD) before any AF demagnetizations to remove multi-domain like component. To correct the non-ideality, anhysteretic remanent magnetizations (ARMs) are imparted with their directions parallel to natural remanent magnetizations and laboratory-imparted thermoremanent magnetizations (TRMs) and measured before and after laboratory heating. These ARMs are used to correct remanence anisotropies, possible interaction effects originated from the non-ideal grains and TRM changes caused by laboratory alterations. TRMs are imparted by heating specimens above their Curie temperatures and then cooling to room temperature at once to simulate nature conditions. These cycles are done in vacuum to suppress alterations in laboratory. Obtained results are judged by selection criteria, including a check for validity of the ARM corrections.It has been demonstrated that successful paleointensities are obtained from historical lavas in Japan and Hawaii, and from baked clay samples from a reconstructed ancient kiln, with the flow-mean precision of 5-10%. In case of old volcanic rocks, however, the method does not necessarily seem to be perfect. We will summarize these points in

  6. A Method for Selecting between Fisher's Linear Classification Functions and Least Absolute Deviation in Predictive Discriminant Analysis.

    ERIC Educational Resources Information Center

    Meshbane, Alice; Morris, John D.

    A method for comparing the cross-validated classification accuracy of Fisher's linear classification functions (FLCFs) and the least absolute deviation is presented under varying data conditions for the two-group classification problem. With this method, separate-group as well as total-sample proportions of current classifications can be compared…

  7. Optimizing methods to recover absolute FRET efficiency from immobilized single molecules.

    PubMed

    McCann, James J; Choi, Ucheor B; Zheng, Liqiang; Weninger, Keith; Bowen, Mark E

    2010-08-04

    Microscopy-based fluorescence resonance energy transfer (FRET) experiments measure donor and acceptor intensities by isolating these signals with a series of optical elements. Because this filtering discards portions of the spectrum, the observed FRET efficiency is dependent on the set of filters in use. Similarly, observed FRET efficiency is also affected by differences in fluorophore quantum yield. Recovering the absolute FRET efficiency requires normalization for these effects to account for differences between the donor and acceptor fluorophores in their quantum yield and detection efficiency. Without this correction, FRET is consistent across multiple experiments only if the photophysical and instrument properties remain unchanged. Here we present what is, to our knowledge, the first systematic study of methods to recover the true FRET efficiency using DNA rulers with known fluorophore separations. We varied optical elements to purposefully alter observed FRET and examined protein samples to achieve quantum yields distinct from those in the DNA samples. Correction for calculated instrument transmission reduced FRET deviations, which can facilitate comparison of results from different instruments. Empirical normalization was more effective but required significant effort. Normalization based on single-molecule photobleaching was the most effective depending on how it is applied. Surprisingly, per-molecule gamma-normalization reduced the peak width in the DNA FRET distribution because anomalous gamma-values correspond to FRET outliers. Thus, molecule-to-molecule variation in gamma has an unrecognized effect on the FRET distribution that must be considered to extract information on sample dynamics from the distribution width.

  8. Using new luminescence methods to date the Palaeolithic: the example of Kalambo Falls

    NASA Astrophysics Data System (ADS)

    Duller, Geoff; Tooth, Stephen; Barham, Larry

    2013-04-01

    The Palaeolithic site of Kalambo Falls in the north of Zambia was the subject of detailed study by J.D. Clark in the 1950s with 4 excavations being located within 1 km of each other in a basin upstream of the falls. A rich palaeolithic tool record was recovered, but the value of this record was limited by the lack of chronological information available. In 2006, one of the excavation sites was re-investigated (Barham et al., 2009), including examination of the stratigraphic context and collection of samples for luminescence dating. Many of the sediments in the Kalambo basin were deposited by fluvial activity. Dose distributions in the single grain quartz optically stimulated luminescence (OSL) measurements of the youngest sediments are consistent with incomplete bleaching. However, the residual doses obtained are typically less than 10 Gy, and so for older sediments the impact of incomplete bleaching becomes insignificant. The oldest samples are affected by a different problem, namely saturation of the OSL signal, and many grains are saturated. However in all cases some grains give finite equivalent dose values, making it feasible to calculate single grain quartz OSL ages, but it is difficult to assess whether these ages are reliable or not. Thermally transferred OSL (TT-OSL) from quartz is able to date much older samples due to the high saturation dose of this signal (Duller and Wintle, 2012). Comparison of the TT-OSL and OSL demonstrates that the OSL signal yields age underestimates as samples near saturation. Only by using the two luminescence methods is it possible to create an absolute chronology for this key site stretching back over half a million years. This study demonstrates the potential of using these two luminescence signals together for dating Palaeolithic sites throughout Africa and beyond. Barham, L., Duller, G. A. T., Plater, A. J., Tooth, S. and Turner, S. (2009). Recent excavations at Kalambo Falls, Zambia. Antiquity 83(322). Duller, G. A. T. and

  9. Absolute calibration method for nanosecond-resolved, time-streaked, fiber optic light collection, spectroscopy systems

    NASA Astrophysics Data System (ADS)

    Johnston, Mark D.; Oliver, Bryan V.; Droemer, Darryl W.; Frogget, Brent; Crain, Marlon D.; Maron, Yitzhak

    2012-08-01

    This paper describes a convenient and accurate method to calibrate fast (<1 ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such systems are inherently difficult to calibrate due to the lack of sufficiently intense, calibrated light sources. Such a system is used to collect spectral data on plasmas generated in electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA) at Sandia National Laboratories. On RITS, plasma light is collected through a small diameter (200 μm) optical fiber and recorded on a fast streak camera at the output of a 1 meter Czerny-Turner monochromator. For this paper, a 300 W xenon short arc lamp (Oriel Model 6258) was used as the calibration source. Since the radiance of the xenon arc varies from cathode to anode, just the area around the tip of the cathode ("hotspot") was imaged onto the fiber, to produce the highest intensity output. To compensate for chromatic aberrations, the signal was optimized at each wavelength measured. Output power was measured using 10 nm bandpass interference filters and a calibrated photodetector. These measurements give power at discrete wavelengths across the spectrum, and when linearly interpolated, provide a calibration curve for the lamp. The shape of the spectrum is determined by the collective response of the optics, monochromator, and streak tube across the spectral region of interest. The ratio of the spectral curve to the measured bandpass filter curve at each wavelength produces a correction factor (Q) curve. This curve is then applied to the experimental data and the resultant spectra are given in absolute intensity units (photons/sec/cm2/steradian/nm). Error analysis shows this method to be accurate to within +/- 20%, which represents a high level of accuracy for this type of measurement.

  10. Absolute calibration method for nanosecond-resolved, time-streaked, fiber optic light collection, spectroscopy systems.

    PubMed

    Johnston, Mark D; Oliver, Bryan V; Droemer, Darryl W; Frogget, Brent; Crain, Marlon D; Maron, Yitzhak

    2012-08-01

    This paper describes a convenient and accurate method to calibrate fast (<1 ns resolution) streaked, fiber optic light collection, spectroscopy systems. Such systems are inherently difficult to calibrate due to the lack of sufficiently intense, calibrated light sources. Such a system is used to collect spectral data on plasmas generated in electron beam diodes fielded on the RITS-6 accelerator (8-12MV, 140-200kA) at Sandia National Laboratories. On RITS, plasma light is collected through a small diameter (200 μm) optical fiber and recorded on a fast streak camera at the output of a 1 meter Czerny-Turner monochromator. For this paper, a 300 W xenon short arc lamp (Oriel Model 6258) was used as the calibration source. Since the radiance of the xenon arc varies from cathode to anode, just the area around the tip of the cathode ("hotspot") was imaged onto the fiber, to produce the highest intensity output. To compensate for chromatic aberrations, the signal was optimized at each wavelength measured. Output power was measured using 10 nm bandpass interference filters and a calibrated photodetector. These measurements give power at discrete wavelengths across the spectrum, and when linearly interpolated, provide a calibration curve for the lamp. The shape of the spectrum is determined by the collective response of the optics, monochromator, and streak tube across the spectral region of interest. The ratio of the spectral curve to the measured bandpass filter curve at each wavelength produces a correction factor (Q) curve. This curve is then applied to the experimental data and the resultant spectra are given in absolute intensity units (photons/sec/cm(2)/steradian/nm). Error analysis shows this method to be accurate to within +∕- 20%, which represents a high level of accuracy for this type of measurement.

  11. AN ACCURATE NEW METHOD OF CALCULATING ABSOLUTE MAGNITUDES AND K-CORRECTIONS APPLIED TO THE SLOAN FILTER SET

    SciTech Connect

    Beare, Richard; Brown, Michael J. I.; Pimbblet, Kevin

    2014-12-20

    We describe an accurate new method for determining absolute magnitudes, and hence also K-corrections, that is simpler than most previous methods, being based on a quadratic function of just one suitably chosen observed color. The method relies on the extensive and accurate new set of 129 empirical galaxy template spectral energy distributions from Brown et al. A key advantage of our method is that we can reliably estimate random errors in computed absolute magnitudes due to galaxy diversity, photometric error and redshift error. We derive K-corrections for the five Sloan Digital Sky Survey filters and provide parameter tables for use by the astronomical community. Using the New York Value-Added Galaxy Catalog, we compare our K-corrections with those from kcorrect. Our K-corrections produce absolute magnitudes that are generally in good agreement with kcorrect. Absolute griz magnitudes differ by less than 0.02 mag and those in the u band by ∼0.04 mag. The evolution of rest-frame colors as a function of redshift is better behaved using our method, with relatively few galaxies being assigned anomalously red colors and a tight red sequence being observed across the whole 0.0 < z < 0.5 redshift range.

  12. A Concurrent Mixed Methods Approach to Examining the Quantitative and Qualitative Meaningfulness of Absolute Magnitude Estimation Scales in Survey Research

    ERIC Educational Resources Information Center

    Koskey, Kristin L. K.; Stewart, Victoria C.

    2014-01-01

    This small "n" observational study used a concurrent mixed methods approach to address a void in the literature with regard to the qualitative meaningfulness of the data yielded by absolute magnitude estimation scaling (MES) used to rate subjective stimuli. We investigated whether respondents' scales progressed from less to more and…

  13. The performance of different propensity score methods for estimating absolute effects of treatments on survival outcomes: A simulation study.

    PubMed

    Austin, Peter C; Schuster, Tibor

    2016-10-01

    Observational studies are increasingly being used to estimate the effect of treatments, interventions and exposures on outcomes that can occur over time. Historically, the hazard ratio, which is a relative measure of effect, has been reported. However, medical decision making is best informed when both relative and absolute measures of effect are reported. When outcomes are time-to-event in nature, the effect of treatment can also be quantified as the change in mean or median survival time due to treatment and the absolute reduction in the probability of the occurrence of an event within a specified duration of follow-up. We describe how three different propensity score methods, propensity score matching, stratification on the propensity score and inverse probability of treatment weighting using the propensity score, can be used to estimate absolute measures of treatment effect on survival outcomes. These methods are all based on estimating marginal survival functions under treatment and lack of treatment. We then conducted an extensive series of Monte Carlo simulations to compare the relative performance of these methods for estimating the absolute effects of treatment on survival outcomes. We found that stratification on the propensity score resulted in the greatest bias. Caliper matching on the propensity score and a method based on earlier work by Cole and Hernán tended to have the best performance for estimating absolute effects of treatment on survival outcomes. When the prevalence of treatment was less extreme, then inverse probability of treatment weighting-based methods tended to perform better than matching-based methods.

  14. The realization of the dipole (γ, γ) method and its application to determine the absolute optical oscillator strengths of helium

    PubMed Central

    Xu, Long-Quan; Liu, Ya-Wei; Kang, Xu; Ni, Dong-Dong; Yang, Ke; Hiraoka, Nozomu; Tsuei, Ku-Ding; Zhu, Lin-Fan

    2015-01-01

    The dipole (γ, γ) method, which is the inelastic x-ray scattering operated at a negligibly small momentum transfer, is proposed and realized to determine the absolute optical oscillator strengths of the vanlence-shell excitations of atoms and molecules. Compared with the conventionally used photoabsorption method, this new method is free from the line saturation effect, which can seriously limit the accuracies of the measured photoabsorption cross sections for discrete transitions with narrow natural linewidths. Furthermore, the Bethe-Born conversion factor of the dipole (γ, γ) method varies much more slowly with the excitation energy than does that of the dipole (e, e) method. Absolute optical oscillator strengths for the excitations of 1s2 → 1 snp(n = 3 − 7) of atomic helium have been determined using the high-resolution dipole (γ, γ) method, and the excellent agreement of the present measurements with both those measured by the dipole (e, e) method and the previous theoretical calculations indicates that the dipole (γ, γ) method is a powerful tool to measure the absolute optical oscillator strengths of the valence-shell excitations of atoms and molecules. PMID:26678298

  15. Determination of absolute configuration using heavy atom based co-crystallization method: Halogen atom effects

    NASA Astrophysics Data System (ADS)

    Wang, Jian-Rong; Fan, Xiaowu; Ding, Qiaoce; Mei, Xuefeng

    2016-09-01

    Heavy atom (chloride, bromide, and iodide) based co-crystals for determination of absolute configuration (AC) for chiral molecules were synthesized and evaluated. Co-crystals of cholestanol and L-ascorbic acid were analysed and the effects and potential benefits of varying the heavy atom are discussed. Changing the halogen atoms (chloride, bromide, or iodide) affects the co-crystal formation, X-ray absorption, and anomalous dispersion, and hence the ability to determine AC.

  16. Bringing the cross-correlation method up to date

    NASA Astrophysics Data System (ADS)

    Statler, Thomas

    1995-03-01

    The cross-correlation (XC) method of Tonry & Davis (1979, AJ, 84, 1511) is generalized to arbitrary parametrized line profiles. In the new algorithm the correlation function itself, rather than the observed galaxy spectrum, is fitted by the model line profile: this removes much of the complication in the error analysis caused by template mismatch. Like the Fourier correlation quotient (FCQ) method of Bender (1990, A&A, 229, 441), the inferred line profiles are, up to a normalization constant, independent of template mismatch as long as there are no blended lines. The standard reduced chi2 is a good measure of the fit of the inferred velocity distribution, largely decoupled from the fit of the spectral template. The updated XC method performs as well as other recently developed methods, with the added virtue of conceptual simplicity.

  17. Bringing the cross-correlation method up to date

    NASA Technical Reports Server (NTRS)

    Statler, Thomas

    1995-01-01

    The cross-correlation (XC) method of Tonry & Davis (1979, AJ, 84, 1511) is generalized to arbitrary parametrized line profiles. In the new algorithm the correlation function itself, rather than the observed galaxy spectrum, is fitted by the model line profile: this removes much of the complication in the error analysis caused by template mismatch. Like the Fourier correlation quotient (FCQ) method of Bender (1990, A&A, 229, 441), the inferred line profiles are, up to a normalization constant, independent of template mismatch as long as there are no blended lines. The standard reduced chi(exp 2) is a good measure of the fit of the inferred velocity distribution, largely decoupled from the fit of the spectral template. The updated XC method performs as well as other recently developed methods, with the added virtue of conceptual simplicity.

  18. 29 CFR 4011.9 - Method and date of issuance of notice; computation of time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Method and date of issuance of notice; computation of time. 4011.9 Section 4011.9 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION CERTAIN REPORTING AND DISCLOSURE REQUIREMENTS DISCLOSURE TO PARTICIPANTS § 4011.9 Method and date of issuance of notice; computation of...

  19. Application of Mean of Absolute Deviation Method for the Selection of Best Nonlinear Component Based on Video Encryption

    NASA Astrophysics Data System (ADS)

    Anees, Amir; Khan, Waqar Ahmad; Gondal, Muhammad Asif; Hussain, Iqtadar

    2013-07-01

    The aim of this work is to make use of the mean of absolute deviation (MAD) method for the evaluation process of substitution boxes used in the advanced encryption standard. In this paper, we use the MAD technique to analyze some popular and prevailing substitution boxes used in encryption processes. In particular, MAD is applied to advanced encryption standard (AES), affine power affine (APA), Gray, Lui J., Residue Prime, S8 AES, SKIPJACK, and Xyi substitution boxes.

  20. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2012-05-15

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  1. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K.; Snyderman, Neal J.; Rowland, Mark S.

    2010-07-13

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  2. Determination of the Absolute Configuration of the Pseudo-Symmetric Natural Product Elatenyne by the Crystalline Sponge Method.

    PubMed

    Urban, Sylvia; Brkljača, Robert; Hoshino, Manabu; Lee, Shoukou; Fujita, Makoto

    2016-02-18

    Elatenyne is a marine natural product that was isolated in 1986. Despite its simple 2,2'-bifuranyl backbone, its relative structure was only recently determined. The absolute configuration of elatenyne has still not been unequivocally confirmed because of its pseudo-meso core structure, which results in a specific rotation, [α]D  , of almost zero. In this work, the structure of natural elatenyne was determined by the crystalline sponge method and the use of a porous coordination network (a crystalline sponge) capable of absorbing organic guests; in the sponge, the absorbed guests are ordered and crystallographically observable. The crystalline sponge could differentiate between the two very similar alkyl side chains, and the absolute structure of elatenyne was thus reliably determined. The total amount required for the experiments was only approximately 100 μg, and the majority (95 μg) could be recovered after the experiments.

  3. Luminescence Dating of Sediments: An Increasingly Diverse Family of Methods and Range of Applications

    NASA Astrophysics Data System (ADS)

    Roberts, H. M.

    2015-12-01

    In recent years, the term 'luminescence dating' has expanded its meaning such that today it encompasses a range of luminescence dating methods and materials. Whilst the fundamental principles that underlie these different dating methods are essentially the same, namely that the event typically being recorded is the last exposure of the material to light or to heat, the various luminescence dating techniques do differ in their suitability in different situations. Today, in the field of luminescence dating of sediments, there are a number of minerals that can be used for dating (quartz and feldspar being the most commonly used), and for each mineral it is possible to obtain a number of different luminescence signals (some obtained using optical stimulation, and some obtained by heating). These different luminescence signals may build-up and deplete in the natural environment at different rates from each other, and can span quite different time ranges. Additionally, the scale of analysis used in luminescence dating can now be varied (ranging from single sand-sized grains to multiple grains), as can the size range of the materials used for dating (ranging from fine-silt, coarse-silt, and sand-sized grains, through to large clasts and rock surfaces). Having such flexibility in the range of minerals, luminescence signals, grain sizes, and the scales of analysis available for dating, means that it is now possible to optimise the materials and methods selected for dating in any particular study in response to the precise scientific question to be addressed, the time-range of interest, and the likely mechanisms of re-setting of the luminescence signal in the context that is to be dated. In this paper, the flexibility offered by the growing family of luminescence techniques will be outlined by considering some of the different minerals, luminescence signals, and dramatically different timescales (tens of years to millions of years) potentially available for sediment dating

  4. Method and apparatus for ultra-high-sensitivity, incremental and absolute optical encoding

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B. (Inventor)

    1999-01-01

    An absolute optical linear or rotary encoder which encodes the motion of an object (3) with increased resolution and encoding range and decreased sensitivity to damage to the scale includes a scale (5), which moves with the object and is illuminated by a light source (11). The scale carries a pattern (9) which is imaged by a microscope optical system (13) on a CCD array (17) in a camera head (15). The pattern includes both fiducial markings (31) which are identical for each period of the pattern and code areas (33) which include binary codings of numbers identifying the individual periods of the pattern. The image of the pattern formed on the CCD array is analyzed by an image processor (23) to locate the fiducial marking, decode the information encoded in the code area, and thereby determine the position of the object.

  5. Combining sub-Nyquist sampling and chirp decomposition for a high-precision and speed absolute distance measurement method.

    PubMed

    Liu, Guodong; Lu, Cheng; Liu, Bingguo; Chen, Fengdong; Gan, Yu

    2016-12-10

    A high-precision and speed absolute distance measurement based on swept-wavelength interferometry is reported. A powerful method combining sub-Nyquist sampling and chirp decomposition for dispersion mismatch compensation is proposed. A standard deviation of 0.72 μm is obtained for the measurement of a target located at 3.9 m, which is better than the traditional method. The measurement can be completed in 1.9 s when the frequency range is 4.26 THz, which is much better than chirp decomposition without sub-Nyquist sampling.

  6. 29 CFR 4062.10 - Method and date of filing; where to file.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Method and date of filing; where to file. 4062.10 Section 4062.10 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION LIABILITY LIABILITY FOR TERMINATION OF SINGLE-EMPLOYER PLANS § 4062.10 Method and date of filing; where to file. (a) Method of filing. The PBGC applies...

  7. An absolute method for determination of misalignment of an immersion ultrasonic transducer.

    PubMed

    Narayanan, M M; Singh, Narender; Kumar, Anish; Babu Rao, C; Jayakumar, T

    2014-12-01

    An absolute methodology has been developed for quantification of misalignment of an ultrasonic transducer using a corner-cube retroreflector. The amplitude based and the time of flight (TOF) based C-scans of the reflector are obtained for various misalignments of the transducer. At zero degree orientation of the transducer, the vertical positions of the maximum amplitude and the minimum TOF in the C-scan coincide. At any other orientation of the transducer with the horizontal plane, there is a vertical shift in the position of the maximum amplitude with respect to the minimum TOF. The position of the minimum (TOF) remains the same irrespective of the orientation of the transducer and hence is used as a reference for any misalignment of the transducer. With the measurement of the vertical shift and the horizontal distance between the transducer and the vertex of the reflector, the misalignment of the transducer is quantified. Based on the methodology developed in the present study, retroreflectors are placed in the Indian 500MWe Prototype Fast Breeder Reactor for assessment of the orientation of the ultrasonic transducer prior to the under-sodium ultrasonic scanning for detection of any protrusion of the subassemblies.

  8. ESR dating pleistocene barnacles from BC and Maine: a new method for tracking sea level change.

    PubMed

    Blackwell, Bonnie A B; Gong, J J J; Skinner, Anne R; Blais-Stevens, Andrée; Nelson, Robert E; Blickstein, Joel I B

    2010-02-01

    Barnacles have never been successfully dated by electron spin resonance (ESR). Living mainly in the intertidal zone, barnacles die when sea level changes cause their permanent exposure. Thus, dating the barnacles dates past sea level changes. From this, we can measure apparent sea level changes that occur due to ocean volume changes, crustal isostasy, and tectonics. ESR can date aragonitic mollusc shells ranging in age from 5 ka to at least 500 ka. By modifying the standard ESR method for molluscs to chemically dissolve 20 microm from off the shells, six barnacle samples from Norridgewock, Maine, and Khyex River, British Columbia, were tested for suitability for ESR dating. Due to Mn2+ interference peaks, the four Maine barnacle samples were not datable by ESR. Two barnacles from BC, which lacked Mn2+ interference, yielded a mean ESR age of 15.1 +/- 1.0 ka. These ages agree well with 14C dates on the barnacles themselves and wood in the overlying glaciomarine sediment. Although stability tests to calculate the mean dating signal lifetime and more ESR calibration tests against other barnacles of known age are needed to ensure the method's accuracy, ESR can indeed date Balanus, and thus, sea level changes.

  9. A practical method of estimating standard error of age in the fission track dating method

    USGS Publications Warehouse

    Johnson, N.M.; McGee, V.E.; Naeser, C.W.

    1979-01-01

    A first-order approximation formula for the propagation of error in the fission track age equation is given by PA = C[P2s+P2i+P2??-2rPsPi] 1 2, where PA, Ps, Pi and P?? are the percentage error of age, of spontaneous track density, of induced track density, and of neutron dose, respectively, and C is a constant. The correlation, r, between spontaneous are induced track densities is a crucial element in the error analysis, acting generally to improve the standard error of age. In addition, the correlation parameter r is instrumental is specifying the level of neutron dose, a controlled variable, which will minimize the standard error of age. The results from the approximation equation agree closely with the results from an independent statistical model for the propagation of errors in the fission-track dating method. ?? 1979.

  10. Method based on chirp decomposition for dispersion mismatch compensation in precision absolute distance measurement using swept-wavelength interferometry.

    PubMed

    Lu, Cheng; Liu, Guodong; Liu, Bingguo; Chen, Fengdong; Hu, Tao; Zhuang, Zhitao; Xu, Xinke; Gan, Yu

    2015-12-14

    We establish a theoretical model of dispersion mismatch in absolute distance measurements using swept-wavelength interferometry (SWI) and propose a novel dispersion mismatch compensation method called chirp decomposition. This method separates the dispersion coefficient and distance under test, which ensures dispersion mismatch compensation without introducing additional random errors. In the measurement of a target located at 3.9 m, a measurement resolution of 45.9 μm is obtained, which is close to the theoretical resolution, and a standard deviation of 0.74 μm is obtained, which is better than the traditional method. The measurement results are compared to a single-frequency laser interferometer. The target moves from 1 m to 3.7 m, and the measurement precision using the new method is less than 0.81 μm.

  11. Optical phase step method for absolute ranging interferometry using computer-generated holograms

    NASA Astrophysics Data System (ADS)

    Deininger, Martin; Wang, Lingli; Gerstner, Klaus; Tschudi, Theo

    1995-09-01

    One main problem of an interferometric measurement is to evaluate the object distance from the interference function. One of the known methods that delivers the object phase is the phase step method. Here we introduce computer-generated holograms to realize parallel phase steps without phase modulation of the reference path.

  12. Absolute Zero

    NASA Astrophysics Data System (ADS)

    Donnelly, Russell J.; Sheibley, D.; Belloni, M.; Stamper-Kurn, D.; Vinen, W. F.

    2006-12-01

    Absolute Zero is a two hour PBS special attempting to bring to the general public some of the advances made in 400 years of thermodynamics. It is based on the book “Absolute Zero and the Conquest of Cold” by Tom Shachtman. Absolute Zero will call long-overdue attention to the remarkable strides that have been made in low-temperature physics, a field that has produced 27 Nobel Prizes. It will explore the ongoing interplay between science and technology through historical examples including refrigerators, ice machines, frozen foods, liquid oxygen and nitrogen as well as much colder fluids such as liquid hydrogen and liquid helium. A website has been established to promote the series: www.absolutezerocampaign.org. It contains information on the series, aimed primarily at students at the middle school level. There is a wealth of material here and we hope interested teachers will draw their student’s attention to this website and its substantial contents, which have been carefully vetted for accuracy.

  13. Correction to Method of Establishing the Absolute Radiometric Accuracy of Remote Sensing Systems While On-orbit Using Characterized Stellar Sources

    NASA Technical Reports Server (NTRS)

    Bowen, Howard S.; Cunningham, Douglas M.

    2007-01-01

    The contents include: 1) Brief history of related events; 2) Overview of original method used to establish absolute radiometric accuracy of remote sensing instruments using stellar sources; and 3) Considerations to improve the stellar calibration approach.

  14. Development of absolute hot-wire anemometry by the 3omega method.

    PubMed

    Heyd, Rodolphe; Hadaoui, Abdallah; Fliyou, Mohamed; Koumina, Abdelaziz; El Hassani Ameziane, Lahcen; Outzourhit, Abdelkader; Saboungi, Marie-Louise

    2010-04-01

    We have developed hot-wire anemometry applying the 3omega method. The approach is based on the same heat transfer process as traditional anemometry, but substituting the constant current by a sinusoidal current and using synchronous detection to measure the conductive-convective exchange coefficient and the gas flow rate. Our theoretical model is tested with air flow at 300 K under atmospheric pressure: The experimental results are in agreement with the numerical simulation, justifying the technical choices in the 3omega method and the approximations made. The effectiveness of the 3omega method for measuring the flow rate and the conductive-convective exchange coefficient between the hot wire and flowing gas is discussed.

  15. ESR dating of quartz extracted from quaternary and neogene sediments: method, potential and actual limits

    NASA Astrophysics Data System (ADS)

    Laurent, M.; Falguères, C.; Bahain, J. J.; Rousseau, L.; Van Vliet Lanoé, B.

    ESR dating of fluvial, fluvio-marine and beach sediment has been tested using the Al centre in quartz grains from a basin and fossil beaches located around the Manche Channel. Dating was performed in conjunction with sedimentological, stratigraphical and neotectonical studies. The technical basis of the method is presented in the light of the study made on recent and fossil sediment in order to establish a procedure for the determination of the palaeodose. The application on a Neogene Basin samples allows to push back the dating ESR limits. Results show that ESR dating of sediment can provide chronozons which are necessary to the uderstanding of the history of a basin where classical chronological markers do not exist.

  16. Method of excess fractions with application to absolute distance metrology: wavelength selection and the effects of common error sources.

    PubMed

    Falaggis, Konstantinos; Towers, David P; Towers, Catherine E

    2012-09-20

    Multiwavelength interferometry (MWI) is a well established technique in the field of optical metrology. Previously, we have reported a theoretical analysis of the method of excess fractions that describes the mutual dependence of unambiguous measurement range, reliability, and the measurement wavelengths. In this paper wavelength, selection strategies are introduced that are built on the theoretical description and maximize the reliability in the calculated fringe order for a given measurement range, number of wavelengths, and level of phase noise. Practical implementation issues for an MWI interferometer are analyzed theoretically. It is shown that dispersion compensation is best implemented by use of reference measurements around absolute zero in the interferometer. Furthermore, the effects of wavelength uncertainty allow the ultimate performance of an MWI interferometer to be estimated.

  17. Absolute Summ

    NASA Astrophysics Data System (ADS)

    Phillips, Alfred, Jr.

    Summ means the entirety of the multiverse. It seems clear, from the inflation theories of A. Guth and others, that the creation of many universes is plausible. We argue that Absolute cosmological ideas, not unlike those of I. Newton, may be consistent with dynamic multiverse creations. As suggested in W. Heisenberg's uncertainty principle, and with the Anthropic Principle defended by S. Hawking, et al., human consciousness, buttressed by findings of neuroscience, may have to be considered in our models. Predictability, as A. Einstein realized with Invariants and General Relativity, may be required for new ideas to be part of physics. We present here a two postulate model geared to an Absolute Summ. The seedbed of this work is part of Akhnaton's philosophy (see S. Freud, Moses and Monotheism). Most important, however, is that the structure of human consciousness, manifest in Kenya's Rift Valley 200,000 years ago as Homo sapiens, who were the culmination of the six million year co-creation process of Hominins and Nature in Africa, allows us to do the physics that we do. .

  18. Mapping the African thunderstorm center in absolute units using Schumann resonance spectral decomposition method

    NASA Astrophysics Data System (ADS)

    Dyrda, Michal; Kulak, Andrzej; Mlynarczyk, Janusz

    2015-04-01

    Monitoring of the global lightning activity provides a very useful tool to study the global warming phenomenon and the other longer-scale climate changes induced by humans. The lightning activity is measured using various observational methods form space (optical satellite observations) as well as from the ground mostly by VLF /LF lightning detection networks, i.e. World Wide Lightning Location Network (WWLLN) or lightning detection network (LINET) in Europe. However, the global lightning activity measurements are possible only in the ELF range. Here we examine the African thunderstorm activity center, which is the most violent and active one. In a spherical damped resonator, such as the Earth-ionosphere cavity, the electromagnetic field is described by the solution of an inhomogeneous wave equation. For such equation the general solution can be expressed by the superposition of the solutions of the homogeneous equation, describing the resonance field, and the component, which is quite strong close to the source and weakens with source-observer separation. Thus, the superposition of the standing wave field with the field of traveling waves, which supply the energy from the lighting discharges to the global resonator, is a main reason for an asymmetric shape of the observational Schumann resonance (SR) power spectra, which highly deviate from the Lorentz curves. It is possible to separate this component from the signal using the spectrum decomposition method proposed by Kułak et al. [2006]. In our approach, we apply the inverse problem solution for determining the distance of the dominant lightning source. The distances to the thunderstorm centers are calculated using the analytical models for the electromagnetic waves propagation in the Earth-ionosphere cavity. Such forms of analytic solutions of the resonant field in the spherical cavity is the zonal harmonic series representation, described by Mushtak and Williams [2002] and we calculated the sets of such curves

  19. Absolute Photometry

    NASA Astrophysics Data System (ADS)

    Hartig, George

    1990-12-01

    The absolute sensitivity of the FOS will be determined in SV by observing 2 stars at 3 epochs, first in 3 apertures (1.0", 0.5", and 0.3" circular) and then in 1 aperture (1.0" circular). In cycle 1, one star, BD+28D4211 will be observed in the 1.0" aperture to establish the stability of the sensitivity and flat field characteristics and improve the accuracy obtained in SV. This star will also be observed through the paired apertures since these are not calibrated in SV. The stars will be observed in most detector/grating combinations. The data will be averaged to form the inverse sensitivity functions required by RSDP.

  20. A multi-centennial time series of well-constrained ΔR values for the Irish Sea derived using absolutely-dated shell samples from the mollusc Arctica islandica

    NASA Astrophysics Data System (ADS)

    Butler, P. G.; Scourse, J. D.; Richardson, C. A.; Wanamaker, A. D., Jr.

    2009-04-01

    Determinations of the local correction (ΔR) to the globally averaged marine radiocarbon reservoir age are often isolated in space and time, derived from heterogeneous sources and constrained by significant uncertainties. Although time series of ΔR at single sites can be obtained from sediment cores, these are subject to multiple uncertainties related to sedimentation rates, bioturbation and interspecific variations in the source of radiocarbon in the analysed samples. Coral records provide better resolution, but these are available only for tropical locations. It is shown here that it is possible to use the shell of the long-lived bivalve mollusc Arctica islandica as a source of high resolution time series of absolutely-dated marine radiocarbon determinations for the shelf seas surrounding the North Atlantic ocean. Annual growth increments in the shell can be crossdated and chronologies can be constructed in a precise analogue with the use of tree-rings. Because the calendar dates of the samples are known, ΔR can be determined with high precision and accuracy and because all the samples are from the same species, the time series of ΔR values possesses a high degree of internal consistency. Presented here is a multi-centennial (AD 1593 - AD 1933) time series of 31 ΔR values for a site in the Irish Sea close to the Isle of Man. The mean value of ΔR (-62 14C yrs) does not change significantly during this period but increased variability is apparent before AD 1750.

  1. 42 CFR 456.435 - Description of methods and criteria: Continued stay review dates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Description of methods and criteria: Continued stay review dates. 456.435 Section 456.435 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS UTILIZATION CONTROL Utilization Control: Intermediate Care Facilities...

  2. 29 CFR 4219.19 - Method and date of issuance; computation of time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Method and date of issuance; computation of time. 4219.19 Section 4219.19 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION WITHDRAWAL LIABILITY FOR MULTIEMPLOYER PLANS NOTICE, COLLECTION, AND REDETERMINATION OF WITHDRAWAL LIABILITY Redetermination of Withdrawal...

  3. Methods for calculating the absolute entropy and free energy of biological systems based on ideas from polymer physics.

    PubMed

    Meirovitch, Hagai

    2010-01-01

    The commonly used simulation techniques, Metropolis Monte Carlo (MC) and molecular dynamics (MD) are of a dynamical type which enables one to sample system configurations i correctly with the Boltzmann probability, P(i)(B), while the value of P(i)(B) is not provided directly; therefore, it is difficult to obtain the absolute entropy, S approximately -ln P(i)(B), and the Helmholtz free energy, F. With a different simulation approach developed in polymer physics, a chain is grown step-by-step with transition probabilities (TPs), and thus their product is the value of the construction probability; therefore, the entropy is known. Because all exact simulation methods are equivalent, i.e. they lead to the same averages and fluctuations of physical properties, one can treat an MC or MD sample as if its members have rather been generated step-by-step. Thus, each configuration i of the sample can be reconstructed (from nothing) by calculating the TPs with which it could have been constructed. This idea applies also to bulk systems such as fluids or magnets. This approach has led earlier to the "local states" (LS) and the "hypothetical scanning" (HS) methods, which are approximate in nature. A recent development is the hypothetical scanning Monte Carlo (HSMC) (or molecular dynamics, HSMD) method which is based on stochastic TPs where all interactions are taken into account. In this respect, HSMC(D) can be viewed as exact and the only approximation involved is due to insufficient MC(MD) sampling for calculating the TPs. The validity of HSMC has been established by applying it first to liquid argon, TIP3P water, self-avoiding walks (SAW), and polyglycine models, where the results for F were found to agree with those obtained by other methods. Subsequently, HSMD was applied to mobile loops of the enzymes porcine pancreatic alpha-amylase and acetylcholinesterase in explicit water, where the difference in F between the bound and free states of the loop was calculated. Currently

  4. Apatite fission track dating by LA-ICP-MS and External Detector Method: How do they stack up?

    NASA Astrophysics Data System (ADS)

    Seiler, C.; Gleadow, A. J.; Kohn, B. P.

    2013-12-01

    Analysis of trace element compositions by laser ablation ICP-MS has become a widely used tool to determine in-situ ages in geochronology. Although used primarily for U-Pb dating, LA-ICP-MS has been successfully adapted to other dating techniques such as apatite fission track (Hasebe et al., 2004) or (U-Th)/He (Boyce et al., 2006), making it an ideal tool for multi-system thermochronological studies. LA-ICP-MS fission track dating has several important advantages over the traditional external detector method (EDM), particularly in terms of sample turn-around time and the fact that neutron irradiations (and the handling of radioactive materials) are no longer necessary, while providing a similar level of in-situ information. Perhaps the most important benefits of LA-ICP-MS fission track dating is that it could potentially be used as an absolute dating technique with no Zeta-calibration necessary. However, beyond the initial study of Hasebe et al. (2004), little work has been done to compare results obtained by LA-ICP-MS with those from EDM analysis, and it remains unclear whether the two methods yield equivalent results. We present an extensive dataset of fission track results that were analysed using both LA-ICP-MS and EDM dating. The samples were selected to represent a variety of compositions, with single grain ages ranging from a few million to over a billion years. Both techniques were applied on identical grains, thereby eliminating uncertainties associated with natural variability. The comparison shows that, with a few exceptions, single grain fission track ages from LA-ICP-MS and EDM are concordant within analytical uncertainties and scatter symmetrically around the 1:1 correlation line. Although the relative difference in single grain ages varies significantly in either direction (up to 70%), there are no systematic variations between the two methods suggesting that this variation is simply due to random sampling effects. However, we did find systematic

  5. Absolute x-ray energy calibration over a wide energy range using a diffraction-based iterative method.

    PubMed

    Hong, Xinguo; Chen, Zhiqiang; Duffy, Thomas S

    2012-06-01

    In this paper, we report a method of precise and fast absolute x-ray energy calibration over a wide energy range using an iterative x-ray diffraction based method. Although accurate x-ray energy calibration is indispensable for x-ray energy-sensitive scattering and diffraction experiments, there is still a lack of effective methods to precisely calibrate energy over a wide range, especially when normal transmission monitoring is not an option and complicated micro-focusing optics are fixed in place. It is found that by using an iterative algorithm the x-ray energy is only tied to the relative offset of sample-to-detector distance, which can be readily varied with high precision of the order of 10(-5) -10(-6) spatial resolution using gauge blocks. Even starting with arbitrary initial values of 0.1 Å, 0.3 Å, and 0.4 Å, the iteration process converges to a value within 3.5 eV for 31.122 keV x-rays after three iterations. Different common diffraction standards CeO(2), Au, and Si show an energy deviation of 14 eV. As an application, the proposed method has been applied to determine the energy-sensitive first sharp diffraction peak of network forming GeO(2) glass at high pressure, exhibiting a distinct behavior in the pressure range of 2-4 GPa. Another application presented is pair distribution function measurement using calibrated high-energy x-rays at 82.273 keV. Unlike the traditional x-ray absorption-based calibration method, the proposed approach does not rely on any edges of specific elements, and is applicable to the hard x-ray region where no appropriate absorption edge is available.

  6. Improving age constraints on Patagonian glaciations using a new luminescence dating method for feldspars

    NASA Astrophysics Data System (ADS)

    Smedley, R. K.; Glasser, N. F.; Duller, G. A.

    2013-12-01

    Multiple moraine ridges are preserved in the Lago Buenos Aires and Lago Pueyrrédon valleys, east of the Northern Patagonian Icefield and offer a unique perspective on understanding past environmental change in the mid-latitudes of the Southern Hemisphere. Previous age constraints provided for the moraine ridges relies on cosmogenic isotope dating and constraining radiocarbon and 40Ar/36Ar ages. Providing age constraints using luminescence dating of the glaciofluvial landforms associated with the moraine ridges offers great potential to contribute towards improving the accuracy and precision of age constraints in such challenging glacial settings. This is the first study to use a new luminescence dating method recently developed for feldspars (Thomsen et al. 2008) to constrain the ages of moraine deposition. A range of sediments were sampled from the outwash plains and glaciofluvial channels that are associated with moraine deposition in the Lago Buenos Aires and Lago Pueyrrédon valleys. Elevation measurements and the geomorphological context of the outwash plains and glaciofluvial channels are used to relate the sampled material to the associated moraine ridges, and therefore constrain the ages of moraine deposition in the valleys. Moraine ridges dated using cosmogenic isotope dating to the Last Glacial Maximum are the main focus of this study, but the overall aim is to provide a new dating technique that can be used to understand the temporal and spatial extent of terrestrial environmental change during past glaciations of the mid-latitudes in the Southern Hemisphere. Thomsen, K.J., Murray, A.S., Jain, M. and Bøtter-Jensen, L. 2008. Laboratory fading rates of various luminescence signals from feldspar-rich sediment extracts. Radiation Measurements 43, 1474 - 1486.

  7. In vivo absolute quantification for mouse muscle metabolites using an inductively coupled synthetic signal injection method and newly developed 1H/31P dual tuned probe

    PubMed Central

    Lee, Donghoon; Marro, Kenneth; Mathis, Mark; Shankland, Eric; Hayes, Cecil

    2013-01-01

    Purpose To obtain robust estimates of 31P metabolite content in mouse skeletal muscles using our recently developed MR absolute quantification method and a custom-built 1H/31P dual tuned radiofrequency (RF) coil optimized for mouse leg. Materials and Methods We designed and fabricated a probe consisting of two dual tuned 1H/31P solenoid coils: one leg was inserted to each solenoid. The mouse leg volume coil was incorporated with injector coils for MR absolute quantification. The absolute quantification method uses a synthetic reference signal injection approach and solves several challenges in MR absolute quantification including changes of coil loading and receiver gains. Results The 1H/31P dual tuned probe was composed of two separate solenoid coils, one for each leg, to increase coil filling factors and signal-to-noise ratio. Each solenoid was equipped with a second coil to allow injection of reference signals. 31P metabolite concentrations determined for normal mice were well within the expected range reported in the literature. Conclusion We developed an RF probe and an absolute quantification approach adapted for mouse skeletal muscle. PMID:24464912

  8. Implementation of an absolute brain 1H-MRS quantification method to assess different tissue alterations in multiple sclerosis.

    PubMed

    Bagory, Matthieu; Durand-Dubief, Françoise; Ibarrola, Danielle; Comte, Jean-Christophe; Cotton, François; Confavreux, Christian; Sappey-Marinier, Dominique

    2012-10-01

    Magnetic resonance spectroscopy has emerged as a sensitive modality to detect early and diffuse alterations in multiple sclerosis. Recently, the hypothesis of neurodegenerative pathogenesis has highlightened the interest for measurement of metabolites concentrations, to gain specificity, in a large brain volume encompassing different tissue alterations. Therefore, we proposed in this paper the implementation of an absolute quantification method based on localized spectroscopy at short (30 ms) and long (135 ms) echo time of a volume including normal appearing white matter, cortical gray matter, and lesions. First, methodological developments were implemented including external calibration, and corrections of phased-array coil sensitivity and cerebrospinal fluid volume contribution. Second, these improvements were validated and optimized using an original methodology based on simulations of brain images with lesions. Finally, metabolic alterations were assessed in 65 patients including 26 relapsing-remitting, 17 primary-progressive (PP), 22 secondary-progressive (SP) patients, and in 23 normal subjects. Results showed increases of choline, creatine, and myo-inositol concentrations in PP and SP patients compared to controls, whereas the concentration of N-acetyl compounds remained constant. The major finding of this study was the identification of Cho concentration and Cho/tNA ratio as putative markers of progressive onset, suggesting interesting perspectives in detection and followup of neurodegenerative processes.

  9. The Impact of Enhanced He and CNONa Abundances on Globular Cluster Relative Age-Dating Methods

    NASA Astrophysics Data System (ADS)

    Marín-Franch, Antonio; Cassisi, Santi; Aparicio, Antonio; Pietrinferni, Adriano

    2010-05-01

    The impact that unrecognized differences in the chemical patterns of Galactic globular clusters (GGCs) have on their relative age determinations is studied. The two most widely used relative age-dating methods, horizontal and vertical, together with the more recent relative MS-fitting method, were carefully analyzed on a purely theoretical basis. The BaSTI library was adopted to perform the present analysis. We find that relative ages derived using the horizontal and vertical methods are largely dependent on the initial He content and heavy element distribution. Unrecognized cluster-to-cluster chemical abundance differences can lead to an error in the derived relative ages as large as ~0.5 (or ~6 Gyr if an age of 12.8 Gyr is adopted for normalization) and even larger for some extreme cases. It is shown that the relative MS-fitting method is by far the age-dating technique for which undetected cluster-to-cluster differences in the He abundance have less impact. Present results are used in order to pose constraints on the maximum possible spread in the He and CNONa elements abundances on the basis of the estimates—taken from the literature—of the GGCs relative age dispersion obtained with the various relative age-dating techniques. Finally, it is shown that the age-metallicity relation found for young GGCs by the GC Treasury program is a real age sequence and cannot be produced by variations in the He and/or heavy element distribution.

  10. Effect of various methods for rectum delineation on relative and absolute dose-volume histograms for prostate IMRT treatment planning

    SciTech Connect

    Kusumoto, Chiaki; Ohira, Shingo; Miyazaki, Masayoshi; Ueda, Yoshihiro; Isono, Masaru; Teshima, Teruki

    2016-07-01

    Several reports have dealt with correlations of late rectal toxicity with rectal dose-volume histograms (DVHs) for high dose levels. There are 2 techniques to assess rectal volume for reception of a specific dose: relative-DVH (R-DVH, %) that indicates relative volume for a vertical axis, and absolute-DVH (A-DVH, cc) with its vertical axis showing absolute volume of the rectum. The parameters of DVH vary depending on the rectum delineation method, but the literature does not present any standardization of such methods. The aim of the present study was to evaluate the effects of different delineation methods on rectal DVHs. The enrollment for this study comprised 28 patients with high-risk localized prostate cancer, who had undergone intensity-modulated radiation therapy (IMRT) with the prescription dose of 78 Gy. The rectum was contoured with 4 different methods using 2 lengths, short (Sh) and long (Lg), and 2 cross sections, rectum (Rec) and rectal wall (Rw). Sh means the length from 1 cm above the seminal vesicles to 1 cm below the prostate and Lg the length from the rectosigmoid junction to the anus. Rec represents the entire rectal volume including the rectal contents and Rw the rectal volume of the area with a wall thickness of 4 mm. We compared dose-volume parameters by using 4 rectal contour methods for the same plan with the R-DVHs as well as the A-DVHs. For the high dose levels, the R-DVH parameters varied widely. The mean of V{sub 70} for Sh-Rw was the highest (19.4%) and nearly twice as high as that for Lg-Rec (10.4%). On the contrary, only small variations were observed in the A-DVH parameters (4.3, 4.3, 5.5, and 5.5 cc for Sh-Rw, Lg-Rw, Sh-Rec, and Lg-Rec, respectively). As for R-DVHs, the parameters of V{sub 70} varied depending on the rectal lengths (Sh-Rec vs Lg-Rec: R = 0.76; Sh-Rw vs Lg-Rw: R = 0.85) and cross sections (Sh-Rec vs Sh-Rw: R = 0.49; Lg-Rec vs Lg-Rw: R = 0.65). For A-DVHs, however, the parameters of Sh rectal A-DVHs hardly changed

  11. Dating archeological ceramics from the Valley of Vitor, Arequipa by the TL method

    NASA Astrophysics Data System (ADS)

    Cano, N. F.; Arizaca, E. C.; Yauri, J. M.; Arenas, J. S. A.; Watanabe, S.

    The age of some ancient pottery from the Valley of Vitor in the region of Arequipa, Peru, is determined by the thermoluminescence (TL) method. For dating, a 325 °C TL peak was used and irradiation with γ-dose from 5 to 50 Gy was carried out for the additive method, and from 0.4 to 5 Gy for the regeneration method. For these dose values, the TL intensity is observed to grow linearly, obtaining an accumulated dose of 1.62±0.09 Gy and 1.36±0.03 Gy for the additive and regeneration methods, respectively. The age (A) of the sample was calculated by the two methods, being A=867±195 years after Christ (AC) for the additive method and A=1050±157 years AC for the regeneration method. Both results are within 800-1200 years AC, which is the period of the Wari culture.

  12. SU-E-T-804: Verification of the BJR-25 Method of KQ Determination for CyberKnife Absolute Dosimetry

    SciTech Connect

    Gersh, J; Willett, B

    2015-06-15

    Purpose: Absolute calibration of the CyberKnife is performed using a 6cm-diameter cone defined at 80cm SAD. Since kQ is defined using PDD values determined using 10×10 cm fields at 100cm SSD, the PDD must be corrected in order to correctly apply the quality conversion factor. The accepted method is based on equivalent field-size conversions of PDD values using BJR25. Using the new InCise MLC system, the CK is capable of generating a rectangular field equivalent to 10×10 cm square field. In this study, a comparison is made between kQ values determined using the traditional BJR25 method and the MLC method introduced herein. Methods: First, kQ(BJR) is determined: a PDD is acquired using a 6cm circular field at 100cm SSD, its field size converted to an equivalent square, and PDD converted to a 10×10cm field using the appropriate BJR25 table. Maintaining a consistent setup, the collimator is changed, and the MLC method is used. Finally, kQ is determined using PDDs acquired with a 9.71×10.31cm at 100cm SSD. This field is produced by setting the field to a size of 7.77×8.25cm (since it is defined at 80cm SAD). An exact 10×10cm field since field size is relegated to increments of its leaf width (0.25cm). This comparison is made using an Exradin A1SL, IBA CC08, IBA CC13, and an Exradin A19. For each detector and collimator type, the beam injector was adjusted to give 5 different beam qualities; representing a range of clinical systems. Results: Averaging across all beam qualities, kQ(MLC) differed from kQ(BJR) by less than 0.15%. The difference between the values increased with detector volume. Conclusion: For CK users with standard cone collimators, the BJR25 method has been verified. For CK users the MLC system, a technique is described to determine kQ. Primary author is the President/Owner of Spectrum Medical Physics, LLC, a company which maintains contracts with Siemens Healthcare and Standard Imaging, Inc.

  13. Development of a nanofiltration method for bone collagen 14C AMS dating

    NASA Astrophysics Data System (ADS)

    Boudin, Mathieu; Boeckx, Pascal; Buekenhoudt, Anita; Vandenabeele, Peter; Van Strydonck, Mark

    2013-01-01

    Radiocarbon dating of bones is usually performed on the collagen fraction. However, this collagen can contain exogenous molecules, including humic substances (HSs) and/or other soil components that may have a different age than the bone. Incomplete removal can result in biased 14C dates. Ultrafiltration of collagen, dissolved as gelatin (molecular weight (MW) ∼100,000 Dalton), has received considerable attention to obtain more reliable dates. Ultrafiltration is an effective method of removal of low-molecular weight contaminants from bone collagen but it does not remove high-molecular weight contaminants, such as cross-linked humic collagen complexes. However, comparative dating studies have raised the question whether this cleaning step itself may introduce contamination with carbon from the filters used. In this study, a nanofiltration method was developed using a ceramic filter to avoid a possible extraneous carbon contamination introduced by the filter. This method should be applicable to various protein materials e.g. collagen, silk, wool, leather and should be able to remove low-molecular and high molecular weight HSs. In this study bone collagen was hot acid hydrolyzed to amino acids and nanofiltrated. A filter with a molecular weight cutoff (MWCO) of 450 Dalton was chosen in order to collect the amino acids in the permeate and the HSs in the retentate. Two pilot studies were set up. Two nanofiltration types were tested in pilot study 1: dead end and cross flow filtration. Humic substance (HS)-solutions with fossil carbon and modern hydrolyzed collagen contaminated with HSs were filtrated and analyzed with spectrofluorescence to determine the HS removal. Cross flow nanofiltration showed the most efficient HS removal. A second pilot study based upon these results was set up wherein only cross flow filtration was performed. 14C measurements of the permeates of hydrolyzed modern collagen contaminated with fossil HSs demonstrate a significant but incomplete

  14. Dating of iron gall ink using the dissolution-diffusion method.

    PubMed

    Li, Biao; Xie, Peng

    2015-03-01

    In many criminal and civil cases, some questioned documents are written with iron gall ink. Determining the date when an iron gall ink entry was written can be important to assess the authenticity of a document. A dissolution-diffusion method was successfully employed to draw aging curves of iron gall ink entries stored in controlled conditions over 40 months. Calibration curves were created to indicate the relationship between the average dissolution-diffusion rate of ink components and the age of ink entries stored under natural aging conditions. As preliminary findings of this study, the mixed solution of dimethyl formamide (DMF) and anhydrous ethanol was suitable to dissolve the dye of iron gall ink strokes made at different time. It was also determined that brands of iron gall inks, types of paper, and thickness of iron gall ink strokes had varying impacts on estimating the dates of iron gall ink strokes.

  15. Proxy-dating the Tschirgant rockslide event with the U/Th method

    NASA Astrophysics Data System (ADS)

    Ostermann, Marc; Sanders, Diethard

    2010-05-01

    Age-dating of catastrophic rockslides is a prerequisite to understanding the potential controls over mass-wasting events. Rockslides are mostly dated with the radiocarbon method and/or surface exposure dating. In addition, in a pilot study on the carbonate-lithic rockslide of Fern Pass (Tyrol, Austria) it was demonstrated that U/Th dating of diagenetic cement formed newly within the rockslide deposit can provide a good proxy age of the mass-wasting event (Ostermann et al., 2007; Prager et al., 2009). Proxy-dating carbonate-lithic rockslides with the U/Th method is based on CaCO³ precipitates (cements, stalactites) formed along the underside of rockslide boulders. Because the CaCO³ precipitates form only after mass-wasting, their U/Th age represents a minimum proxy age of the event. In the present study, we applied U/Th dating to stalactites sampled from the prominent Tschirgant rockslide (Tyrol, Austria). The Tschirgant rockslide detached from a mountain flank more than 1400 m in vertical height, from an intensely deformed succession of Triassic dolostones and cellular dolomites. The rockslide mass with an estimated volume of >200 x 106 m³ is spread over an area of 9 km². The maximum runout of the rockslide is 6.2 km, and the fahrböschung is 12° (Prager et al., 2008). For the Tschirgant rockslide, five radiocarbon ages of organic remnants from five different locations suggest two distinct mass-wasting events (1: 3753 ± 191 cal. a BP; 2: 3151 ± 359 cal a BP) (Patzelt, 2004). We sampled soda-straw stalactites from the underside of boulders at two different locations for U/Th dating. The U/Th ages of the stalactites are 3650 ± 350 a and 2800 ± 100 a. These ages are consistent with a hypothesis (Ostermann et al., 2007) that, in carbonate-lithic rockslide masses, precipitation of cement and stalactites starts closely or perhaps immediately after mass-wasting. Thus, the U/Th ages may confirm the existence of two separate mass-wasting events, as suggested by the

  16. Crater-based dating of geological units on Mars: Methods and application for the new global geological map

    NASA Astrophysics Data System (ADS)

    Platz, Thomas; Michael, Gregory; Tanaka, Kenneth L.; Skinner, James A.; Fortezzo, Corey M.

    2013-07-01

    The new, post-Viking generation of Mars orbital imaging and topographical data provide significant higher-resolution details of surface morphologies, which induced a new effort to photo-geologically map the surface of Mars at 1:20,000,000 scale. Although from unit superposition relations a relative stratigraphical framework can be compiled, it was the ambition of this mapping project to provide absolute unit age constraints through crater statistics. In this study, the crater counting method is described in detail, starting with the selection of image data, type locations (both from the mapper's and crater counter's perspectives) and the identification of impact craters. We describe the criteria used to validate and analyse measured crater populations, and to derive and interpret crater model ages. We provide examples of how geological information about the unit's resurfacing history can be retrieved from crater size-frequency distributions. Three cases illustrate short-, intermediate, and long-term resurfacing histories. In addition, we introduce an interpretation-independent visualisation of the crater resurfacing history that uses the reduction of the crater population in a given size range relative to the expected population given the observed crater density at larger sizes. From a set of potential type locations, 48 areas from 22 globally mapped units were deemed suitable for crater counting. Because resurfacing ages were derived from crater statistics, these secondary ages were used to define the unit age rather than the base age. Using the methods described herein, we modelled ages that are consistent with the interpreted stratigraphy. Our derived model ages allow age assignments to be included in unit names. We discuss the limitations of using the crater dating technique for global-scale geological mapping. Finally, we present recommendations for the documentation and presentation of crater statistics in publications.

  17. Crater-based dating of geological units on Mars: methods and application for the new global geological map

    USGS Publications Warehouse

    Platz, Thomas; Michael, Gregory; Tanaka, Kenneth L.; Skinner, James A.; Fortezzo, Corey M.

    2013-01-01

    The new, post-Viking generation of Mars orbital imaging and topographical data provide significant higher-resolution details of surface morphologies, which induced a new effort to photo-geologically map the surface of Mars at 1:20,000,000 scale. Although from unit superposition relations a relative stratigraphical framework can be compiled, it was the ambition of this mapping project to provide absolute unit age constraints through crater statistics. In this study, the crater counting method is described in detail, starting with the selection of image data, type locations (both from the mapper’s and crater counter’s perspectives) and the identification of impact craters. We describe the criteria used to validate and analyse measured crater populations, and to derive and interpret crater model ages. We provide examples of how geological information about the unit’s resurfacing history can be retrieved from crater size–frequency distributions. Three cases illustrate short-, intermediate, and long-term resurfacing histories. In addition, we introduce an interpretation-independent visualisation of the crater resurfacing history that uses the reduction of the crater population in a given size range relative to the expected population given the observed crater density at larger sizes. From a set of potential type locations, 48 areas from 22 globally mapped units were deemed suitable for crater counting. Because resurfacing ages were derived from crater statistics, these secondary ages were used to define the unit age rather than the base age. Using the methods described herein, we modelled ages that are consistent with the interpreted stratigraphy. Our derived model ages allow age assignments to be included in unit names. We discuss the limitations of using the crater dating technique for global-scale geological mapping. Finally, we present recommendations for the documentation and presentation of crater statistics in publications.

  18. Simultaneous determination of the absolute configuration of twelve monosaccharide enantiomers from natural products in a single injection by UPLC-UV/MS method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In natural product chemistry, it is often crucial to determine sugar composition as well as the absolute configuration of each monosaccharide in glycosides. An ultra-performance liquid chromatography method using both photodiode array (PDA) and mass spectrometry detectors (UPLC-UV/MS) was developed....

  19. Radiocarbon Dating.

    PubMed

    Van Strydonck, Mark

    2016-04-01

    Although most historians and art historians consider the radiocarbon dating technique not to be very precise by their criteria, the method has gained much importance over the last decades. Radiocarbon dating is increasingly used in the field of textile research and old polychrome statues, but also objects made of ivory, stucco, paper, and parchment are dated with the technique. Especially after the introduction of the AMS technique, a boom of this type of research has been noticed.

  20. Simulated fissioning of uranium and testing of the fission-track dating method

    USGS Publications Warehouse

    McGee, V.E.; Johnson, N.M.; Naeser, C.W.

    1985-01-01

    A computer program (FTD-SIM) faithfully simulates the fissioning of 238U with time and 235U with neutron dose. The simulation is based on first principles of physics where the fissioning of 238U with the flux of time is described by Ns = ??f 238Ut and the fissioning of 235U with the fluence of neutrons is described by Ni = ??235U??. The Poisson law is used to set the stochastic variation of fissioning within the uranium population. The life history of a given crystal can thus be traced under an infinite variety of age and irradiation conditions. A single dating attempt or up to 500 dating attempts on a given crystal population can be simulated by specifying the age of the crystal population, the size and variation in the areas to be counted, the amount and distribution of uranium, the neutron dose to be used and its variation, and the desired ratio of 238U to 235U. A variety of probability distributions can be applied to uranium and counting-area. The Price and Walker age equation is used to estimate age. The output of FTD-SIM includes the tabulated results of each individual dating attempt (sample) on demand and/or the summary statistics and histograms for multiple dating attempts (samples) including the sampling age. An analysis of the results from FTD-SIM shows that: (1) The external detector method is intrinsically more precise than the population method. (2) For the external detector method a correlation between spontaneous track count, Ns, and induced track count, Ni, results when the population of grains has a stochastic uranium content and/or when the counting areas between grains are stochastic. For the population method no correlation can exist. (3) In the external detector method the sampling distribution of age is independent of the number of grains counted. In the population method the sampling distribution of age is highly dependent on the number of grains counted. (4) Grains with zero-track counts, either in Ns or Ni, are in integral part of

  1. Ascertaining year of birth/age at death in forensic cases: A review of conventional methods and methods allowing for absolute chronology.

    PubMed

    Lynnerup, Niels; Kjeldsen, Henrik; Zweihoff, Ralf; Heegaard, Steffen; Jacobsen, Christina; Heinemeier, Jan

    2010-09-10

    Based on an actual case, where we were able to ascertain the year of birth of three dead babies found in a deep-freezer to within 1-2 years (1986, 1988 and 2004, respectively), we review the current state of forensic age determination/year of birth determination. The age of an individual (year of birth) is often a fundamental piece of data in connection with forensic identification of unidentified bodies. The methods most often used are based on determining various morphological, age-related, changes on the skeleton (or teeth, although odontological methods are not reviewed in this paper). As such, these methods are all relative, i.e. they do not furnish calendar ages or years, but an estimate of the age at death, with a rather large range, i.e. the methods rely on biological aging following the chronological aging. More recently, methods have been proposed using more direct ascertainment of age at death, e.g. protein racemisation, or, as in our case, radiocarbon methods. Especially the latter method may in fact yield absolute ages (years of birth), because (14)C activity, as measured in specific proteins in specific cells or tissues in the body, were in equilibrium with the so-called bomb-pulse, when these proteins were formed (at birth). The bomb pulse reflects a dramatic change in atmospheric (14)C content due to nuclear bomb testing, and these dramatic changes can be rather tightly related to single calendar years.

  2. THE IMPACT OF ENHANCED He AND CNONa ABUNDANCES ON GLOBULAR CLUSTER RELATIVE AGE-DATING METHODS

    SciTech Connect

    MarIn-Franch, Antonio; Aparicio, Antonio; Cassisi, Santi; Pietrinferni, Adriano E-mail: antapaj@iac.e E-mail: pietrinferni@oa-teramo.inaf.i

    2010-05-10

    The impact that unrecognized differences in the chemical patterns of Galactic globular clusters (GGCs) have on their relative age determinations is studied. The two most widely used relative age-dating methods, horizontal and vertical, together with the more recent relative MS-fitting method, were carefully analyzed on a purely theoretical basis. The BaSTI library was adopted to perform the present analysis. We find that relative ages derived using the horizontal and vertical methods are largely dependent on the initial He content and heavy element distribution. Unrecognized cluster-to-cluster chemical abundance differences can lead to an error in the derived relative ages as large as {approx}0.5 (or {approx}6 Gyr if an age of 12.8 Gyr is adopted for normalization) and even larger for some extreme cases. It is shown that the relative MS-fitting method is by far the age-dating technique for which undetected cluster-to-cluster differences in the He abundance have less impact. Present results are used in order to pose constraints on the maximum possible spread in the He and CNONa elements abundances on the basis of the estimates-taken from the literature-of the GGCs relative age dispersion obtained with the various relative age-dating techniques. Finally, it is shown that the age-metallicity relation found for young GGCs by the GC Treasury program is a real age sequence and cannot be produced by variations in the He and/or heavy element distribution.

  3. A BAYESIAN METHOD FOR CALCULATING REAL-TIME QUANTITATIVE PCR CALIBRATION CURVES USING ABSOLUTE PLASMID DNA STANDARDS

    EPA Science Inventory

    In real-time quantitative PCR studies using absolute plasmid DNA standards, a calibration curve is developed to estimate an unknown DNA concentration. However, potential differences in the amplification performance of plasmid DNA compared to genomic DNA standards are often ignore...

  4. Radioacarbon in dissolved organic carbon, a possible groundwater dating method: Case studies from western Canada

    SciTech Connect

    Wassenaar, L.; Aravena, R. ); Hendry, J. ); Fritz, P. )

    1991-08-01

    This paper explores the feasibility of using {sup 14}C in dissolved organic carbon (DOC) as an alternative isotopic groundwater dating method. Two hydrogeologically contrasting groundwater systems were tested; the Cretaceous age Milk River aquifer, and low-permeability, organic rich, Wisconsinan age Prairie tills in southern Alberta, Canada. Comparisons of radiocarbon data were made between DOC fractions, dissolved inorganic carbon (DIC), and several DIC geochemical age correction models along well defined flow paths. The data presented demonstrate that {sup 14}C dating of DOC fractions can indeed provide an alternative method for determining isotopic groundwater ages, under suitable conditions. However, detailed information may be required regarding (1) the geologic nature of the aquifer and its flow system, (2) the isotopically conservative behavior of DOC, (3) the initial {sup 14}C activity of DOC in recharge, and (4) the effect of bacterial redox processes on the {sup 14}C activity of DOC. In the Milk River aquifer, DOC {sup 14}C ages were successfully used to estimate groundwater residence times, as well as to further refine input parameter assumptions for the DIC method. In the Prairie tills, DOC {sup 14}C ages were used to establish a maximum age for the pore waters in an environment where the DIC method is especially problematic.

  5. 29 CFR 4041A.3 - Method and date of filing; where to file; computation of time; issuances to third parties.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Method and date of filing; where to file; computation of time; issuances to third parties. 4041A.3 Section 4041A.3 Labor Regulations Relating to Labor (Continued) PENSION BENEFIT GUARANTY CORPORATION PLAN TERMINATIONS TERMINATION OF MULTIEMPLOYER PLANS General Provisions § 4041A.3 Method and date of...

  6. Time lapse imaging of water content with geoelectrical methods: on the interest of working with absolute water content data

    NASA Astrophysics Data System (ADS)

    Dumont, Gaël; Pilawski, Tamara; Robert, Tanguy; Hermans, Thomas; Garré, Sarah; Nguyen, Frederic

    2016-04-01

    The electrical resistivity tomography is a suitable method to estimate the water content of a waste material and detect changes in water content. Various ERT profiles, both static data and time-lapse, where acquired on a landfill during the Minerve project. In the literature, the relative change of resistivity (Δρ/ρ) is generally computed. For saline or heat tracer tests in the saturated zone, the Δρ/ρ can be easily translated into pore water conductivity or underground temperature changes (provided that the initial salinity or temperature condition is homogeneous over the ERT panel extension). For water content changes in the vadose zone resulting of an infiltration event or injection experiment, many authors also work with the Δρ/ρ or relative changes of water content Δθ/θ (linked to the change of resistivity through one single parameter: the Archie's law exponent "m"). This parameter is not influenced by the underground temperature and pore fluid conductivity (ρ¬w) condition but is influenced by the initial water content distribution. Therefore, you never know if the loss of Δθ/θ signal is representative of the limit of the infiltration front or more humid initial condition. Another approach for the understanding of the infiltration process is the assessment of the absolute change of water content (Δθ). This requires the direct computation of the water content of the waste from the resistivity data. For that purpose, we used petrophysical laws calibrated with laboratory experiments and our knowledge of the in situ temperature and pore fluid conductivity parameters. Then, we investigated water content changes in the waste material after a rainfall event (Δθ= Δθ/θ* θ). This new observation is really representatives of the quantity of water infiltrated in the waste material. However, the uncertainty in the pore fluid conductivity value may influence the computed water changes (Δθ=k*m√(ρw) ; where "m" is the Archie's law exponent

  7. An absolutely dated high-resolution stalagmite record from Lianhua Cave in central China: Climate forcing and comparison with Wanxiang Cave and Dongge Cave records over the past 2000 years

    NASA Astrophysics Data System (ADS)

    Li, Hong-Chun; Yin, Jian-Jun; Shen, Chuan-Chou; Mii, Horng-Sheng; Li, Ting-Yong

    2015-04-01

    A 33-cm long aragonite stalagmite (LHD-1) from Lianhua Cave has been dated by MC-ICPMS 230Th/U method on 41 horizons. Very high U contents (1~6ppm) and low Th contents yield excellent 230Th/U dates which provide reliable chronology of the stalagmite on sub-decadal time scale over the past 3350 years. A total of 1716 samples have been measured for δ18O and δ13C, spanning annual resolution over the past 1820 years. The stalagmite δ18O is not only influenced by the 'amount effect', but also affected by the moisture source. Enhanced the tropical monsoon trough under strong EASM brings higher spring quarter rainfall with isotopically light monsoonal moisture in the cave site, resulting in lighter stalagmite δ18O. On decadal or longer time scales, increased solar activity produces warmer condition and stronger summer monsoon which lead to wet climates. On interannual-to-decadal scales, the Walker Circulation under El Niño conditions during cold periods will shift toward the central Pacific and result in weakening of EASM. Under such a circumstance, dry climates will be prevailed in the study area. Based on the δ18O and δ13C records, we have deciphered climatic and vegetation changes of the study area in decadal scales. The highly precise dated LHD-1 record has been compared with previous published Wanxiang Cave and Dongge Cave records. Although some similarities can be found, there are major discrepancies among the three well-dated records, especially during AD 500-700 and AD 1300-1600. In additional, the major weak monsoon periods defined in the Wanxiang Cave record during late Tang Dynasty, late Yuan Dynasty and late Ming Dynasty are not supported by the LHD-1 record. The heaviest δ18O peaks (more than five continuous heavy values) over the past 2000 years appeared around AD 1990-2003, 1657-1662, 1220-1228, 663-669, 363-370, and 1082-1090 (in the order of heavy to light). None of these periods occurred Chinese dynasty collapse.

  8. Video meteor light curve analysis of Orionids and Geminids and developing a method for obtaining the absolute light curves of shower meteors from the single station data

    NASA Astrophysics Data System (ADS)

    Grašić, L.; Milanović, N.; Pavlović, D.

    2016-01-01

    We developed a method for obtaining the absolute light curves of the shower meteors from single station video data. We found that even though the height of a meteor atmospheric trajectory obtained by using this method may have a large error, the absolute light curve shape is preserved. We used our method to calculate the F parameters of the Orionid and Geminid light curves. The light curves were obtained from the single station video data by the instrument with a limiting sensitivity of 3.5m. We found that for our sample of the light curves the zenith distance of meteor radiant does not affect the F parameter for either of the two showers. The value of F parameter of the Orionids obtained in this paper matches the values obtained by other authors, whilst for the Geminids it is significantly different.

  9. Testing the Multispecimen Absolute Paleointensity Method with Archaeological Baked Clays and Bricks: New Data for Central Europe

    NASA Astrophysics Data System (ADS)

    Schnepp, Elisabeth; Leonhardt, Roman

    2014-05-01

    The domain-state corrected multiple-specimen paleointensity determination technique (MSP-DSC, Fabian & Leonhardt, EPSL 297, 84, 2010) has been tested for archaeological baked clays and bricks. The following procedure was applied: (1) Exclusion of secondary overprints using alternating field (AF) or thermal demagnetization and assignment of characteristic remanent magnetization (ChRM) direction. (2) Determination of magneto mineralogical alteration using anhysteretic remanent magnetization (ARM) or temperature dependence of susceptibility. (3) Measurement of ARM anisotropy tensor, calculation of the ancient magnetic field direction. (4) Sister specimens were subjected to the MSP-DSC technique aligned (anti-)parallel to the ancient magnetic field direction. (5) Several checks were applied in order to exclude data points from further evaluation: (a) The accuracy of orientation (< 10°), (b) absence of secondary components (< 10°), (c) use of a considerable NRM fraction (20 to 80%), (d) weak alteration (smaller than for domain state change) and finally (e) domain state correction was applied. Bricks and baked clays from archaeological sites with ages between 645 BC and 2003 AD have been subjected to MSP-DSC absolute paleointensity (PI) determination. Aims of study are to check precision and reliability of the method. The obtained PI values are compared with direct field observation, the IGRF, the GUFM1 or Thellier results. The Thellier experiments often show curved lines and pTRM checks fail for higher temperatures. Nevertheless in the low temperature range straight lines have been obtained but they provide scattered paleointensity values. Mean paleointensites have relative errors often exceeding 10%, which are not considered as high quality PI estimates. MSP-DSC experiments for the structures older than 300 years are still under progress. The paleointensities obtained from the MSP-DSC experiments for the young materials (after 1700 AD) have small relative errors of a

  10. In-Situ Apatite Laser Ablation U-Th-Sm/He Dating, Methods and Challenges

    NASA Astrophysics Data System (ADS)

    Pickering, J. E.; Matthews, W.; Guest, B.; Hamilton, B.; Sykes, C.

    2015-12-01

    In-situ, laser ablation U-Th-Sm/He dating is an emerging technique in thermochronology that has been proven as a means to date zircon and monzonite1-5. In-situ U-Th-Sm/He thermochronology eliminates many of the problems and inconveniences associated with traditional, whole grain methods, including; reducing bias in grain selection based on size, shape and clarity; allowing for the use of broken grains and grains with inclusions; avoiding bad neighbour effects; and eliminating safety hazards associated with dissolution. In-situ apatite laser ablation is challenging due to low concentrations of U and Th and thus a low abundance of radiogenic He. For apatite laser ablation to be effective the ultra-high-vacuum (UHV) line must have very low and consistent background levels of He. To reduce He background, samples are mounted in a UHV stable medium. Our mounting process uses a MicroHePP (Microscope Mounted Heated Platen Press) to press samples into FEP (fluorinated ethylene propylene) bonded to an aluminum backing plate. Samples are ablated using a Resonetics 193 nm excimer laser and liberated He is measured using a quadrupole mass spectrometer on the ASI Alphachron noble gas line; collectively this system is known as the Resochron. The ablated sites are imaged using a Zygo Zescope optical profilometer and ablated pit volume measured using PitVol, a custom MatLab algorithm developed to enable precise and unbiased measurement of the ablated pit geometry. We use the well-characterized Durango apatite to demonstrate the accuracy and precision of the method. He liberated from forty-two pits, having volumes between 1700 and 9000 um3, were measured using the Resochron. The ablated sites were imaged using a Zygo Zescope optical profilometer and ablated pit volume measured using PitVol. U, Th and Sm concentrations were measured by laser ablation and the U-Th-Sm/He age calculated by standard age equation. An age of 33.8±0.31 Ma was determined and compares well with conventional

  11. Estimating sap flux densities in date palm trees using the heat dissipation method and weighing lysimeters.

    PubMed

    Sperling, Or; Shapira, Or; Cohen, Shabtai; Tripler, Effi; Schwartz, Amnon; Lazarovitch, Naftali

    2012-09-01

    In a world of diminishing water reservoirs and a rising demand for food, the practice and development of water stress indicators and sensors are in rapid progress. The heat dissipation method, originally established by Granier, is herein applied and modified to enable sap flow measurements in date palm trees in the southern Arava desert of Israel. A long and tough sensor was constructed to withstand insertion into the date palm's hard exterior stem. This stem is wide and fibrous, surrounded by an even tougher external non-conducting layer of dead leaf bases. Furthermore, being a monocot species, water flow does not necessarily occur through the outer part of the palm's stem, as in most trees. Therefore, it is highly important to investigate the variations of the sap flux densities and determine the preferable location for sap flow sensing within the stem. Once installed into fully grown date palm trees stationed on weighing lysimeters, sap flow as measured by the modified sensors was compared with the actual transpiration. Sap flow was found to be well correlated with transpiration, especially when using a recent calibration equation rather than the original Granier equation. Furthermore, inducing the axial variability of the sap flux densities was found to be highly important for accurate assessments of transpiration by sap flow measurements. The sensors indicated no transpiration at night, a high increase of transpiration from 06:00 to 09:00, maximum transpiration at 12:00, followed by a moderate reduction until 08:00; when transpiration ceased. These results were reinforced by the lysimeters' output. Reduced sap flux densities were detected at the stem's mantle when compared with its center. These results were reinforced by mechanistic measurements of the stem's specific hydraulic conductivity. Variance on the vertical axis was also observed, indicating an accelerated flow towards the upper parts of the tree and raising a hypothesis concerning dehydrating

  12. Better characterization of young and old groundwater systems through improved groundwater dating by isotope methods

    NASA Astrophysics Data System (ADS)

    Aggarwal, Pradeep; Suckow, Axel; Newman, Brent; Araguas, Luis; Groening, Manfred; Voss, Clifford; Vitvar, Tomas; Froehlich, Klaus; Kurttas, Turker

    2010-05-01

    . The combined use of radioactive tracers such as carbon-14, chlorine-36 and krypton-81, and numerical hydrodynamic modelling showed inconsistencies in residence time estimates made before the extensive use of accelerator mass spectrometry (AMS) dating methods. Most of the inconsistencies in the use of radiocarbon were the result of contamination with atmospheric CO2 during sampling by the conventional precipitation method. Duplicate analysis of radiocarbon by both sampling methods in selected large aquifers showed consistent differences, up to 10 pMC. The lack of radiocarbon in some deep groundwaters has been confirmed by other long-lived radioisotopes. We have re-evaluated groundwater ages of several of these aquifers coupled with 3-D groundwater models. Our study has demonstrated the usefulness of conservative long-lived radioisotopes for assessing groundwater dynamics of large aquifers containing fossil groundwaters, such as the Nubian Sandstone Aquifer System in Africa and the Guarani aquifer in South America. This presentation will discuss these and related IAEA initiatives in the field of isotope age dating of both young and old groundwaters under various climatic conditions.

  13. Testing the U-Th/4He dating method on carbonates I. Helium diffusion

    NASA Astrophysics Data System (ADS)

    Pinti, D. L.; Ghaleb, B. G.; Sano, Y.; Blanchette, S.; Mathouchanh, E.; Takahata, N.

    2012-12-01

    Corals and other carbonates, such as speleothems, are important climatic-change proxies which need to be precisely dated for paleoclimatic reconstructions. Yet, U-Th disequilibrium method is applicable up to ca. 500 ka old carbonates. Calcite is difficult to date precisely by U-Pb method because of the low U amounts often found and difficulties in correcting for the common lead. Radiogenic 4He produced by decay of 238U and 235U incorporated into carbonates is a potential chronometer of Quaternary, and possibly Tertiary, corals and speleothems. However, several limitations exist for this method, related to the few data on the He diffusion [1] and on the alpha recoil effect in carbonate minerals. We decided to measure 4He by step heating in carbonate samples dated previously by U-Th disequilibrium: a coral (Scleractinia) from Cape Verde dated at 125 ka; a stalagmite from Patagonia dated at 128 ka; and two hydrothermal travertines from the Ziz Valley in Morocco with ages ≥ 500 ka. A one cm3 of each sample was cut by saw, crushed, washed and sieved to 80-100μm and 100-125μm fractions. Crushed samples (0.5 to 1 gram) were loaded in a vacuum crucible and 4He extracted by step heating. Previous step heating experiments on a sub-Arctic flowstone suggested that 4He is mainly released between 400 and 600°C [2]. However, the first coral sample heated at 100°C steps, showed a release pattern profile with 4He mainly released between 200 and 400°C. Measured 4He amount of 2.05 x 10-8 (±0.03% 1σ) ccSTP/g and U content of 2.7 ppm yield a U-4He age of 62.5 ka, lower than that obtained by U-Th disequilibrium. Data were not precise enough to calculate diffusion parameters using the Arrhenius diagram. The second step-heating pyrolysis of the coral using 50°C-steps indicated that all 4He is released between 250 and 350°C. The measured 4He amount was 2.27 x 10-8 (±0.04% 1σ) ccSTP/g, yielding an age of 83 ka, again lower compared to that obtained by U-Th disequilibrium. The

  14. The Radial Growth Rate of Japanese Precious Corals Using Pb-210 Dating Method

    NASA Astrophysics Data System (ADS)

    Yamada, M.; Iwasaki, N.; Suzuki, A.; Aono, T.

    2014-12-01

    Precious corals belong to the subclass Octocorallia of the class Anthozoa. Its major component is calcium carbonate and the crystal structure is high-Mg calcite. Their skeletal axes are used for jewellery, rosary, amulet, etc. They are found mainly in the Japanese coast, the Mediterranean and off the Midway Islands and they are distributed at a depth of 100 m to 1500m. The growing skeletons of precious corals have potential for recording environmental change. Pb-210 is a naturally occurring radionuclide with a half-life of 22.3 years. Pb-210 is a natural sediment marker suitable for dating events that have occurred over the past 100 years and has been used to measure the sedimentation rates of lake and coastal marine sediments. The objectives of this study were to measure the Pb-210 concentration in the skeletons of Japanese red coral, pink coral and white coral and to estimate the radial growth rate using Pb-210 dating method. The radial growth rate of the skeleton can be estimated by the gradual decrease in Pb-210 concentrations measured from the surface inwards. The radial growth rate of the pink coral skeleton (Corallium elatius), collected at depths of 200 to 300 m off the coast of the Ryukyu Islands, Japan, was 0.15 mm/year, so slow that it would take as long as 50 years for a colony to grow to 15 mm in diameter.

  15. Evaluation of methods to derive green-up dates based on daily NDVI satellite observations

    NASA Astrophysics Data System (ADS)

    Doktor, Daniel

    2010-05-01

    Bridging the gap between satellite derived green-up dates and in situ phenological observations has been the purpose of many studies over the last decades. Despite substantial advancements in satellite technology and data quality checks there is as yet no universally accepted method for extracting phenological metrics based on satellite derived vegetation indices. Dependent on the respective method derived green-up dates can vary up to serveral weeks using identical data sets. Consequently, it is difficult to compare various studies and to accurately determine an increased vegetation length due to changing temperature patterns as observed by ground phenological networks. Here, I compared how the characteristic NDVI increase over temperate deciduous forests in Germany in spring relates to respective budburst events observed on the ground. MODIS Terra daily surface reflectances with a 250 m resolution (2000-2008) were gathered to compute daily NDVI values. As ground truth, observations of the extensive phenological network of the German Weather Service were used. About 1500 observations per year and species (Beech, Oak and Birch) were available evenly distributed all over Germany. Two filtering methods were tested to reduce the noisy raw data. The first method only keeps NDVI values which are classified as ‚ideal global quality' and applies on those a temporal moving window where values are removed which differ more than 20% of the mean. The second method uses an adaptation of the BISE (Best Index Slope Extraction) algorithm. Subsequently, three functions were fitted to the selected observations: a simple linear interpolation, a sigmoidal function and a double logistic sigmoidal function allowing to approximate two temporally separated green-up signals. The green-up date was then determined at halfway between minimum and maximum (linear interpolation) or at the inflexion point of the sigmoidal curve. A number of global threshold values (NDVI 0.4,0.5,0.6) and

  16. A single chiroptical spectroscopic method may not be able to establish the absolute configurations of diastereomers: dimethylesters of hibiscus and garcinia acids.

    PubMed

    Polavarapu, Prasad L; Donahue, Emily A; Shanmugam, Ganesh; Scalmani, Giovanni; Hawkins, Edward K; Rizzo, Carmelo; Ibnusaud, Ibrahim; Thomas, Grace; Habel, Deenamma; Sebastian, Dellamol

    2011-06-09

    Electronic circular dichroism (ECD), optical rotatory dispersion (ORD), and vibrational circular dichroism (VCD) spectra of hibiscus acid dimethyl ester have been measured and analyzed in combination with quantum chemical calculations of corresponding spectra. These results, along with those reported previously for garcinia acid dimethyl ester, reveal that none of these three (ECD, ORD, or VCD) spectroscopic methods, in isolation, can unequivocally establish the absolute configurations of diastereomers. This deficiency is eliminated when a combined spectral analysis of either ECD and VCD or ORD and VCD methods is used. It is also found that the ambiguities in the assignment of absolute configurations of diastereomers may also be overcome when unpolarized vibrational absorption is included in the spectral analysis.

  17. A Single Chiroptical Spectroscopic Method May Not Be Able To Establish the Absolute Configurations of Diastereomers: Dimethylesters of Hibiscus and Garcinia Acids

    PubMed Central

    Polavarapu, Prasad L.; Donahue, Emily A.; Shanmugam, Ganesh; Scalmani, Giovanni; Hawkins, Edward K.; Rizzo, Carmelo; Ibnusaud, Ibrahim; Thomas, Grace; Habel, Deenamma; Sebastian, Dellamol

    2013-01-01

    Electronic circular dichroism (ECD), optical rotatory dispersion (ORD), and vibrational circular dichroism (VCD) spectra of hibiscus acid dimethyl ester have been measured and analyzed in combination with quantum chemical calculations of corresponding spectra. These results, along with those reported previously for garcinia acid dimethyl ester, reveal that none of these three (ECD, ORD, or VCD) spectroscopic methods, in isolation, can unequivocally establish the absolute configurations of diastereomers. This deficiency is eliminated when a combined spectral analysis of either ECD and VCD or ORD and VCD methods is used. It is also found that the ambiguities in the assignment of absolute configurations of diastereomers may also be overcome when unpolarized vibrational absorption is included in the spectral analysis. PMID:21568330

  18. Absolute configurations of fungal and plant metabolites by chiroptical methods. ORD, ECD, and VCD studies on phyllostin, scytolide, and oxysporone.

    PubMed

    Mazzeo, Giuseppe; Santoro, Ernesto; Andolfi, Anna; Cimmino, Alessio; Troselj, Pavle; Petrovic, Ana G; Superchi, Stefano; Evidente, Antonio; Berova, Nina

    2013-04-26

    The absolute configuration (AC) of the bioactive metabolites phyllostin (1) and scytolide (2), two hexahydro-1,4-benzodioxines produced by Phyllosticta cirsii, and oxysporone (3), a dihydrofuropyranone recently isolated from a strain of Diplodia africana, has been assigned by computational analysis of their optical rotatory dispersion (ORD), electronic circular dichroism (ECD), and vibrational circular dichroism (VCD) spectra. Computational prediction of ORD, ECD, and VCD allowed us to assign (3S,4aR,8S,8aR) AC to naturally occurring (-)-1, while (4aR,8S,8aR) AC was assigned to (-)-2 employing only ECD and VCD, because in this case ORD analysis turned out to be unsuitable for AC assignment. Theoretical prediction of both ORD and ECD spectra of 3 led to assignment of (4S,5R,6R) AC to (+)-3. In this case a satisfactory agreement between experimental and calculated VCD spectra was obtained only after taking into account solvent effects. This study shows that in the case of flexible and complex natural products only a concerted application of more than a single chiroptical technique permits unambiguous assignment of absolute configuration.

  19. Brief Report: Two Day-Date Processing Methods in an Autistic Savant Calendar Calculator

    ERIC Educational Resources Information Center

    De Marco, Matteo; Iavarone, Alessandro; Santoro, Giovanna; Carlomagno, Sergio

    2016-01-01

    Special ability in computing the day of week for given dates was observed in a 24 year-old male (FB) diagnosed with Asperger syndrome. FB performed almost flawlessly (98.2%) both with past and future dates, over a span of 40 years. Response latency was slower as temporal remoteness of future dates increased. Within the future timespan, FB's…

  20. Dating of black gel pen ink using the dissolution-diffusion method.

    PubMed

    Li, Biao

    2014-01-01

    In many criminal and civil cases in China, the most commonly questioned documents are those written with gel pen ink. An important task for forensic document examiners is to identify whether two or more ink entries in one or more documents were written with the same ink type. The identification of the age of gel ink entries made poses an important and difficult problem for forensic document examiners. In this paper, a dissolution-diffusion method was successfully employed to estimate the relative age of gel ink entries by comparing dissolution-diffusion rates. Using extensive tests, the mixed solution of dimethyl formamide (DMF) and anhydrous ethanol proved to be a suitable solvent and was used to dissolve the dye of gel ink strokes made at different times. As preliminary findings of this study, calibration curves were created to indicate the relationship between the average dissolution-diffusion rate of soluble gel ink components and the age of gel ink entries stored under natural aging conditions. It was also determined that brands of gel inks, types of paper and thickness of gel ink strokes had varying impacts on estimating the dates of gel ink strokes. Experimental results showed that dissolution-diffusion method was applicable for determining the relative age of gel ink entries under certain conditions.

  1. Novel dating method to distinguish between forensic and archeological human skeletal remains by bone mineralization indexes.

    PubMed

    Patonai, Zoltan; Maasz, Gabor; Avar, Peter; Schmidt, Janos; Lorand, Tamas; Bajnoczky, Istvan; Mark, Laszlo

    2013-03-01

    The fast, high-throughput distinction between paleoanthropological remains and recent forensic/clinical bone samples is of vital importance in the field of medicolegal science. In this paper, a novel screening method has been described, using the crystallinity index (C.I.) and carbonate-phosphate index (C/P) as a means to distinguish between archeological and forensic anthropological skeletal findings. According to the Fourier transform infrared spectroscopy analyses, the archeological bone samples are characterized by a range of C.I. between 2.84 and 3.78 and by low C/P values of 0.10-0.33, while the C.I. and C/P ranges of forensic skeletal remains are 2.55-3.18 and 0.38-0.88, respectively. Significant (p < 0.05) changes were observed in C/P as well as C.I. values between the groups of forensic and archeological skeletal samples. The suggested dating method needs only a few milligramms of bone tissue; thus, it can be extremely useful for distiguishing ancient and recent bone fragments.

  2. Dating Violence among High-Risk Young Women: A Systematic Review Using Quantitative and Qualitative Methods

    PubMed Central

    Joly, Lauren E.; Connolly, Jennifer

    2016-01-01

    Our systematic review identified 21 quantitative articles and eight qualitative articles addressing dating violence among high risk young women. The groups of high-risk young women in this review include street-involved, justice-involved, pregnant or parenting, involved with Child Protective Services, and youth diagnosed with a mental health issue. Our meta-analysis of the quantitative articles indicated that 34% (CI = 0.24–0.45) of high-risk young women report that they have been victims of physical dating violence and 45% (CI = 0.31–0.61) of these young women report perpetrating physical dating violence. Significant moderator variables included questionnaire and timeframe. Meta-synthesis of the qualitative studies revealed that high-risk young women report perpetrating dating violence to gain power and respect, whereas women report becoming victims of dating violence due to increased vulnerability. PMID:26840336

  3. Microflora distributions in paleosols: a method for calculating the validity of radiocarbon-dated surfaces

    SciTech Connect

    Mahaney, W.C.; Boyer, M.G.

    1986-08-01

    Microflora (bacteria and fungi) distributions in several paleosols from Mount Kenya, East Africa, provide important information about contamination of buried soil horizons dated by radiocarbon. High counts of bacteria and fungi in buried soils provide evidence for contamination by plant root effects or ground water movement. Profiles with decreasing counts versus depth appear to produce internally consistent and accurate radiocarbon dates. Profiles with disjunct or bimodal distributions of microflora at various depths produce internally inconsistent chronological sequences of radiocarbon-dated buried surfaces. Preliminary results suggest that numbers up to 5 x 10/sup 2/ g/sup -1/ for bacteria in buried A horizons do not appear to affect the validity of /sup 14/C dates. Beyond this threshold value, contamination appears to produce younger dates, the difference between true age and /sup 14/C age increasing with the amount of microflora contamination.

  4. Absolute timing of sulfide and gold mineralization: A comparison of Re-Os molybdenite and Ar-Ar mica methods from the Tintina Gold Belt, Alaska

    USGS Publications Warehouse

    Selby, D.; Creaser, R.A.; Hart, C.J.R.; Rombach, C.S.; Thompson, J.F.H.; Smith, M.T.; Bakke, A.A.; Goldfarb, R.J.

    2002-01-01

    New Re-Os molybdenite dates from two lode gold deposits of the Tintina Gold Belt, Alaska, provide direct timing constraints for sulfide and gold mineralization. At Fort Knox, the Re-Os molybdenite date is identical to the U-Pb zircon age for the host intrusion, supporting an intrusive-related origin for the deposit. However, 40Ar/39Ar dates from hydrothermal and igneous mica are considerably younger. At the Pogo deposit, Re-Os molybdenite dates are also much older than 40Ar/39Ar dates from hydrothermal mica, but dissimilar to the age of local granites. These age relationships indicate that the Re-Os molybdenite method records the timing of sulfide and gold mineralization, whereas much younger 40Ar/39Ar dates are affected by post-ore thermal events, slow cooling, and/or systemic analytical effects. The results of this study complement a growing body of evidence to indicate that the Re-Os chronometer in molybdenite can be an accurate and robust tool for establishing timing relations in ore systems.

  5. An ensemble average method to estimate absolute TEC using radio beacon-based differential phase measurements: Applicability to regions of large latitudinal gradients in plasma density

    NASA Astrophysics Data System (ADS)

    Thampi, Smitha V.; Bagiya, Mala S.; Chakrabarty, D.; Acharya, Y. B.; Yamamoto, M.

    2014-12-01

    A GNU Radio Beacon Receiver (GRBR) system for total electron content (TEC) measurements using 150 and 400 MHz transmissions from Low-Earth Orbiting Satellites (LEOS) is fabricated in house and made operational at Ahmedabad (23.04°N, 72.54°E geographic, dip latitude 17°N) since May 2013. This system receives the 150 and 400 MHz transmissions from high-inclination LEOS. The first few days of observations are presented in this work to bring out the efficacy of an ensemble average method to convert the relative TECs to absolute TECs. This method is a modified version of the differential Doppler-based method proposed by de Mendonca (1962) and suitable even for ionospheric regions with large spatial gradients. Comparison of TECs derived from a collocated GPS receiver shows that the absolute TECs estimated by this method are reliable estimates over regions with large spatial gradient. This method is useful even when only one receiving station is available. The differences between these observations are discussed to bring out the importance of the spatial differences between the ionospheric pierce points of these satellites. A few examples of the latitudinal variation of TEC during different local times using GRBR measurements are also presented, which demonstrates the potential of radio beacon measurements in capturing the large-scale plasma transport processes in the low-latitude ionosphere.

  6. A high-performance liquid chromatography-electronic circular dichroism online method for assessing the absolute enantiomeric excess and conversion ratio of asymmetric reactions.

    PubMed

    Zhang, Xiang; Wang, Mingchao; Li, Li; Yin, Dali

    2017-03-02

    Asymmetric reactions often need to be evaluated during the synthesis of chiral compounds. However, traditional evaluation methods require the isolation of the individual enantiomer, which is tedious and time-consuming. Thus, it is desirable to develop simple, practical online detection methods. We developed a method based on high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) that simultaneously analyzes the material conversion ratio and absolute optical purity of each enantiomer. In particular, only a reverse-phase C18 column instead of a chiral column is required in our method because the ECD measurement provides a g-factor that describes the ratio of each enantiomer in the mixtures. We used our method to analyze the asymmetric hydrosilylation of β-enamino esters, and we discussed the advantage, feasibility, and effectiveness of this new methodology.

  7. A high-performance liquid chromatography-electronic circular dichroism online method for assessing the absolute enantiomeric excess and conversion ratio of asymmetric reactions

    PubMed Central

    Zhang, Xiang; Wang, Mingchao; Li, Li; Yin, Dali

    2017-01-01

    Asymmetric reactions often need to be evaluated during the synthesis of chiral compounds. However, traditional evaluation methods require the isolation of the individual enantiomer, which is tedious and time-consuming. Thus, it is desirable to develop simple, practical online detection methods. We developed a method based on high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) that simultaneously analyzes the material conversion ratio and absolute optical purity of each enantiomer. In particular, only a reverse-phase C18 column instead of a chiral column is required in our method because the ECD measurement provides a g-factor that describes the ratio of each enantiomer in the mixtures. We used our method to analyze the asymmetric hydrosilylation of β-enamino esters, and we discussed the advantage, feasibility, and effectiveness of this new methodology. PMID:28252028

  8. A high-performance liquid chromatography-electronic circular dichroism online method for assessing the absolute enantiomeric excess and conversion ratio of asymmetric reactions

    NASA Astrophysics Data System (ADS)

    Zhang, Xiang; Wang, Mingchao; Li, Li; Yin, Dali

    2017-03-01

    Asymmetric reactions often need to be evaluated during the synthesis of chiral compounds. However, traditional evaluation methods require the isolation of the individual enantiomer, which is tedious and time-consuming. Thus, it is desirable to develop simple, practical online detection methods. We developed a method based on high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) that simultaneously analyzes the material conversion ratio and absolute optical purity of each enantiomer. In particular, only a reverse-phase C18 column instead of a chiral column is required in our method because the ECD measurement provides a g-factor that describes the ratio of each enantiomer in the mixtures. We used our method to analyze the asymmetric hydrosilylation of β-enamino esters, and we discussed the advantage, feasibility, and effectiveness of this new methodology.

  9. The timing of river terrace formation - possibilities and challenges of luminescence dating methods: a case study from Northern Bavaria, Germany

    NASA Astrophysics Data System (ADS)

    Kolb, Thomas; Fuchs, Markus; Zöller, Ludwig

    2014-05-01

    Fluvial terraces are widespread geomorphic features of Quaternary landscapes. Besides tectonics, their formation is predominantly controlled by climatic conditions. Changes in either conditions cause changes in fluvial discharge and sediment load. Therefore, fluvial terraces can be used as important non-continuous sedimentary archives for paleotectonic and paleoenvironmental reconstruction. The information gained from fluvial archives and their significance for paleoenvironmental research, however, strongly depend on a precise dating of the terrace formation. In the past, numerical dating of fluvial sediments has often been proved to be difficult. Radiocarbon dating has been applied on fluvial sediments frequently, but it depends on the presence of organic remains and its dating range is limited to the last ca. 40-50 ka. In contrast, luminescence dating enables the dating of fluvial sediments far beyond the last glacial-interglacial cycle and due to the general abundances of quartz and feldspar, there is almost no limitation of dateable material. Thus, luminescence dating has become a commonly applied method for yielding sedimentation ages of fluvial deposits. Applying luminescence dating techniques to fluvial archives is, however, still far from being a standard method. Several problems, such as incomplete bleaching of the dated material, dosimetric inaccuracies due to the heterogeneity of terrace gravels and difficulties in estimating accurate water contents, have to be considered. Thus, the calculation of OSL ages for fluvial deposits often proves to be challenging and their implications for paleoenvironmental reconstructions always demand a careful interpretation. This contribution illustrates the informative value of fluvial archives for paleoenvironmental research and reveals some of the difficulties that may occur when luminescence dating techniques are applied to river terraces. The presented results are based on a case study, located in an oversized valley

  10. Brief Report: Two Day-Date Processing Methods in an Autistic Savant Calendar Calculator.

    PubMed

    De Marco, Matteo; Iavarone, Alessandro; Santoro, Giovanna; Carlomagno, Sergio

    2016-03-01

    Special ability in computing the day of week for given dates was observed in a 24 year-old male (FB) diagnosed with Asperger syndrome. FB performed almost flawlessly (98.2%) both with past and future dates, over a span of 40 years. Response latency was slower as temporal remoteness of future dates increased. Within the future timespan, FB's performance was consistent with the active use of calendar regularities. On the contrary, within the past timespan (for which no remoteness effect was seen), his performance was mainly linked to memory retrieval of personal events. The case presented here complements the existent literature on calendar calculators, as, for first time, two distinct day-date processing styles are described in the same individual.

  11. Absolute cascade-free cross-sections for the 2S to 2P transition in Zn(+) using electron-energy-loss and merged-beams methods

    NASA Technical Reports Server (NTRS)

    Smith, Steven J.; Man, K.-F.; Chutjian, A.; Mawhorter, R. J.; Williams, I. D.

    1991-01-01

    Absolute cascade-free excitation cross-sections in an ion have been measured for the resonance 2S to 2P transition in Zn(+) using electron-energy-loss and merged electron-ion beams methods. Measurements were carried out at electron energies of below threshold to 6 times threshold. Comparisons are made with 2-, 5-, and 15-state close-coupling and distorted-wave theories. There is good agreement between experiment and the 15-state close-coupling cross-sections over the energy range of the calculations.

  12. Revised method to detect the onset and demise dates of the rainy season in the South American Monsoon areas

    NASA Astrophysics Data System (ADS)

    Garcia, Sâmia R.; Calheiros, Alan J. P.; Kayano, Mary T.

    2016-11-01

    This paper proposes the detection of dates for the onset and demise of the rainy season (ONR and DER, respectively) for some areas within the South American monsoon system (SAMS) region using procedures based on indices which could be easily calculated and subjected to very simple criterion. Previously, the time series of the averaged antisymmetric outgoing longwave radiation ([AOLR]) in each region of interest was used by some authors to detect ONR and DER. This method is referred to as OLD. First, it was proposed in this paper to smooth this time series with the five-pentad running mean ([RM_AOLR]). This modified method is called NEW. Then, an additional modification was adopted by smoothing the [AOLR] with the three-pentad running mean but with the [AOLR] in the most recent pentad being replaced by its climatological value ([RM_AOLRCLI]). This method is called NEW_CLI. For these methods, the criterion was that the first pentad with negative (positive) [AOLR] (or [RM_AOLR] or [RM_AOLRCLI]) is the ONR (DER) date in the region of interest. All these methods were applied for the Central Amazon (CAM) and Western-Central Brazil (WCB) regions during the rainy seasons in the 2001-2013 period. The efficiency of these methods was analyzed using the precipitation estimated from the Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis. The spatial average of the TRMM ([TRMM]) time series with threshold values, which depends on the area and season, was used to determine the ONR and DER dates. In this case, the single method based on the threshold value is called RAIN, and the method which considers the persistence of dry or wet condition is referred to as NEW_RAIN. Comparisons between the methods were performed by calculating the root mean square error (RMSE) when ONR and DER dates obtained from a given method were considered as the true dates. The advantages and disadvantages of the methods were discussed here. It was previously noted that the

  13. Absolutely classical spin states

    NASA Astrophysics Data System (ADS)

    Bohnet-Waldraff, F.; Giraud, O.; Braun, D.

    2017-01-01

    We introduce the concept of "absolutely classical" spin states, in analogy to absolutely separable states of bipartite quantum systems. Absolutely classical states are states that remain classical (i.e., a convex sum of projectors on coherent states of a spin j ) under any unitary transformation applied to them. We investigate the maximal size of the ball of absolutely classical states centered on the maximally mixed state and derive a lower bound for its radius as a function of the total spin quantum number. We also obtain a numerical estimate of this maximal radius and compare it to the case of absolutely separable states.

  14. Recent developments on field gas extraction and sample preparation methods for radiokrypton dating of groundwater

    NASA Astrophysics Data System (ADS)

    Yokochi, Reika

    2016-09-01

    Current and foreseen population growths will lead to an increased demand in freshwater, large quantities of which is stored as groundwater. The ventilation age is crucial to the assessment of groundwater resources, complementing the hydrological model approach based on hydrogeological parameters. Ultra-trace radioactive isotopes of Kr (81 Kr and 85 Kr) possess the ideal physical and chemical properties for groundwater dating. The recent advent of atom trap trace analyses (ATTA) has enabled determination of ultra-trace noble gas radioisotope abundances using 5-10 μ L of pure Kr. Anticipated developments will enable ATTA to analyze radiokrypton isotope abundances at high sample throughput, which necessitates simple and efficient sample preparation techniques that are adaptable to various sample chemistries. Recent developments of field gas extraction devices and simple and rapid Kr separation method at the University of Chicago are presented herein. Two field gas extraction devices optimized for different sampling conditions were recently designed and constructed, aiming at operational simplicity and portability. A newly developed Kr purification system enriches Kr by flowing a sample gas through a moderately cooled (138 K) activated charcoal column, followed by a gentle fractionating desorption. This simple process uses a single adsorbent and separates 99% of the bulk atmospheric gases from Kr without significant loss. The subsequent two stages of gas chromatographic separation and a hot Ti sponge getter further purify the Kr-enriched gas. Abundant CH4 necessitates multiple passages through one of the gas chromatographic separation columns. The presented Kr separation system has a demonstrated capability of extracting Kr with > 90% yield and 99% purity within 75 min from 1.2 to 26.8 L STP of atmospheric air with various concentrations of CH4. The apparatuses have successfully been deployed for sampling in the field and purification of groundwater samples.

  15. Statistical methods to adjust for date and age misreporting to improve estimates of vital rates in Pakistan.

    PubMed

    Pullum, T W

    1991-02-01

    Misreporting of dates and ages poses serious difficulties for the estimation of the age distribution and birth and death rates in many developing countries. The pervasiveness of these problems is illustrated with data from a well-designed on-going survey in Pakistan, the Pakistan Demographic Survey. Methods for reconciling discrepancies, based on the assumptions of constant misreporting and survivorship patterns, are presented. The reasoning behind these methods could be applied much more generally. Research into the cultural interpretations of age and dates, and the nature of possible biases, is called for.

  16. A method for in situ absolute DD yield calibration of neutron time-of-flight detectors on OMEGA using CR-39-based proton detectors

    DOE PAGES

    Waugh, C. J.; Rosenberg, M. J.; Zylstra, A. B.; ...

    2015-05-27

    Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition,more » comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.« less

  17. A method for in situ absolute DD yield calibration of neutron time-of-flight detectors on OMEGA using CR-39-based proton detectors

    SciTech Connect

    Waugh, C. J.; Rosenberg, M. J.; Zylstra, A. B.; Frenje, J. A.; Seguin, F. H.; Petrasso, R. D.; Glebov, V. Yu.; Sangster, T. C.; Stoeckl, C.

    2015-05-27

    Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition, comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.

  18. A method for in situ absolute DD yield calibration of neutron time-of-flight detectors on OMEGA using CR-39-based proton detectors

    SciTech Connect

    Waugh, C. J. Zylstra, A. B.; Frenje, J. A.; Séguin, F. H.; Petrasso, R. D.; Rosenberg, M. J.; Glebov, V. Yu.; Sangster, T. C.; Stoeckl, C.

    2015-05-15

    Neutron time of flight (nTOF) detectors are used routinely to measure the absolute DD neutron yield at OMEGA. To check the DD yield calibration of these detectors, originally calibrated using indium activation systems, which in turn were cross-calibrated to NOVA nTOF detectors in the early 1990s, a direct in situ calibration method using CR-39 range filter proton detectors has been successfully developed. By measuring DD neutron and proton yields from a series of exploding pusher implosions at OMEGA, a yield calibration coefficient of 1.09 ± 0.02 (relative to the previous coefficient) was determined for the 3m nTOF detector. In addition, comparison of these and other shots indicates that significant reduction in charged particle flux anisotropies is achieved when bang time occurs significantly (on the order of 500 ps) after the trailing edge of the laser pulse. This is an important observation as the main source of the yield calibration error is due to particle anisotropies caused by field effects. The results indicate that the CR-39-nTOF in situ calibration method can serve as a valuable technique for calibrating and reducing the uncertainty in the DD absolute yield calibration of nTOF detector systems on OMEGA, the National Ignition Facility, and laser megajoule.

  19. ENHANCED RECOVERY METHODS FOR 85KR AGE-DATING GROUNDWATER: ROYAL WATERSHED, MAINE

    EPA Science Inventory

    Potential widespread use of 85Kr, having a constant input function in the northern hemisphere, for groundwater age-dating would advance watershed investigations. The current input function of tritium is not sufficient to estimate young modern recharge waters. While tri...

  20. A method for estimation of historic contaminant loads using dated sediment cores

    EPA Science Inventory

    Dated sediment cores were used to assess the history of contaminant loads. The contaminant selected must be one that is not significantly remobilized by post depositional processes such as diagenesis. In addition, the core must be from an area with a high deposition rate and litt...

  1. SU-E-T-33: An EPID-Based Method for Testing Absolute Leaf Position for MLC Without Backup Jaws

    SciTech Connect

    Hancock, S; Whitaker, M

    2014-06-01

    Purpose: Methods in common use for MLC leaf position QA are limited to measurements relative to an arbitrary reference position. The authors previously presented an EPID-based method for efficiently testing accuracy of leaf position relative to the mechanical isocenter for MLC with backup jaws. The purpose of this work is to extend that method to the general case of MLC without backup jaws. Methods: A pair of collimator walkout images is used to determine the location of the mechanical isocenter relative to the center of one field using a parameter called X-offset. The method allows for shift of the imager panel to cover subsets of MLC leaves within the limited field of view of the imager. For a shifted panel position, an image of three beam strips defined by a subset of MLC leaves allows determination of the position of each leaf relative to the isocenter. The location of the isocenter is determined by applying X-offset to an image of a single rectangular field obtained at that panel position. The method can also be used to test backup jaws instead of MLC leaves. A software tool was developed to efficiently analyze the images. Results: The software tool reports leaf position and deviation from nominal position, and provides visual displays to facilitate rapid qualitative interpretation. Test results using this method agree well with results using the previous method requiring backup jaws. Test results have been successfully used to recalibrate one model MLC (Elekta MLCi2™). Work in progress includes extension of the software tool to other MLC models, and quantification of reproducibility of the measurements. Conclusion: This work successfully demonstrates a method to efficiently and accurately measure MLC leaf position, or backup jaw position, relative to the mechanical isocenter of the collimator.

  2. Absolute entropy and free energy of fluids using the hypothetical scanning method. I. Calculation of transition probabilities from local grand canonical partition functions

    NASA Astrophysics Data System (ADS)

    Szarecka, Agnieszka; White, Ronald P.; Meirovitch, Hagai

    2003-12-01

    The hypothetical scanning (HS) method provides the absolute entropy and free energy from a Boltzmann sample generated by Monte Carlo, molecular dynamics or any other exact simulation procedure. Thus far HS has been applied successfully to magnetic and polymer chain models; in this paper and the following one it is extended to fluid systems by treating a Lennard-Jones model of argon. With HS a probability Pi approximating the Boltzmann probability of system configuration i is calculated with a stepwise reconstruction procedure, based on adding atoms gradually layer-by-layer to an initially empty volume, where they are replaced in their positions at i. At each step a transition probability (TP) is obtained from local grand canonical partition functions calculated over a limited space of the still unvisited (future) volume, the larger this space the better the approximation. Pi is the product of the step TPs, where ln Pi is an upper bound of the absolute entropy, which leads to upper and lower bounds for the free energy. We demonstrate that very good results for the entropy and the free energy can be obtained for a wide range of densities of the argon system by calculating TPs that are based on only a very limited future volume.

  3. Application of the standard addition method for the absolute quantification of neutral lipids in microalgae using Nile red.

    PubMed

    Bertozzini, Elena; Galluzzi, Luca; Penna, Antonella; Magnani, Mauro

    2011-10-01

    Microalgae are considered one of the best candidates for biofuel production due to their high content in neutral lipids, therefore, an accurate quantification of these lipids in microalgae is fundamental for the identification of the better candidates as biodiesel source. Nile red is a fluorescent dye widely employed for the quantification of neutral lipids in microalgae. Usually, the fluorescence intensity of the stained samples is correlated to the neutral lipid content determined with standard methods, in order to draw a standard curve and deduce the neutral lipids concentration of the unknown samples positioning their fluorescence intensity values on the curve. Standard methods used for the neutral lipids determination are laborious and often implying solvent extraction and/or other transformation (i.e. saponification or transesterification) of the sample. These methods are also time consuming and may give rise to an underestimation of the lipid content due to variable extraction yields. The approach described in this paper combines the standard addition method and the fluorometric staining using Nile red, avoiding the association of traditional neutral lipids quantification methods to the fluorometric determination. After optimization of instrument parameters and staining conditions, a linear correlation between the fluorescence intensity of each sample stained with the Nile red and its neutral lipids content deduced with the standard addition method was identified. The obtained curve allowed the direct determination of neutral lipids content maintaining a linearity range from 0.12 to 12 μg of neutral lipids per ml of sample, without need of pre-concentration. This curve was then used in the quantification of the neutral lipids content in culture of Skeletonema marinoi (Bacillariophyceae) at different days from the inoculum. This method was also successfully applied on Chaetoceros socialis (Bacillariophyceae) and Alexandrium minutum (Dinophyceae).

  4. 42 CFR 456.134 - Description of methods and criteria: Subsequent continued stay review dates; length of stay...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Description of methods and criteria: Subsequent continued stay review dates; length of stay modification. 456.134 Section 456.134 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE PROGRAMS UTILIZATION CONTROL...

  5. 42 CFR 456.129 - Description of methods and criteria: Initial continued stay review date; close professional...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Description of methods and criteria: Initial continued stay review date; close professional scrutiny; length of stay modification. 456.129 Section 456.129 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE...

  6. 42 CFR 456.235 - Description of methods and criteria: Continued stay review dates; length of stay modification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Description of methods and criteria: Continued stay review dates; length of stay modification. 456.235 Section 456.235 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE...

  7. 42 CFR 456.235 - Description of methods and criteria: Continued stay review dates; length of stay modification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 4 2014-10-01 2014-10-01 false Description of methods and criteria: Continued stay review dates; length of stay modification. 456.235 Section 456.235 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL ASSISTANCE...

  8. The Relationship between Balancing Reactions and Reaction Lifetimes: A Consideration of the Potassium-Argon Radiometric Method for Dating Minerals

    ERIC Educational Resources Information Center

    Howard, William A.

    2005-01-01

    A detailed examination of a commonly accepted practice in geology offers an example of how to stimulate critical thinking, teaches students how to read reactions, and challenges students to formulate better experiments for determining mineral ages more accurately. A demonstration of a Potassium-Argon radiometric method for dating minerals is…

  9. Methods for using argon-39 to age-date groundwater using ultra-low-background proportional counting

    DOE PAGES

    Mace, Emily; Aalseth, Craig; Brandenberger, Jill; ...

    2016-12-21

    Argon-39 can be used as a tracer for age-dating glaciers, oceans, and more recently, groundwater. With a half-life of 269 years, 39Ar fills an intermediate age range gap (50–1,000 years) not currently covered by other common groundwater tracers. Therefore, adding this tracer to the data suite for groundwater studies provides an important tool for improving our understanding of groundwater systems. Lastly, we present the methods employed for arriving at an age-date for a given sample of argon degassed from groundwater.

  10. Methods for using argon-39 to age-date groundwater using ultra-low-background proportional counting

    SciTech Connect

    Mace, Emily; Aalseth, Craig; Brandenberger, Jill; Day, Anthony; Hoppe, Eric; Humble, Paul; Keillor, Martin; Kulongoski, Justin; Overman, Cory; Panisko, Mark; Seifert, Allen; White, Signe; Freeburg, Eric Wilcox; Williams, Richard

    2016-12-21

    Argon-39 can be used as a tracer for age-dating glaciers, oceans, and more recently, groundwater. With a half-life of 269 years, 39Ar fills an intermediate age range gap (50–1,000 years) not currently covered by other common groundwater tracers. Therefore, adding this tracer to the data suite for groundwater studies provides an important tool for improving our understanding of groundwater systems. Lastly, we present the methods employed for arriving at an age-date for a given sample of argon degassed from groundwater.

  11. Methods for using argon-39 to age-date groundwater using ultra-low-background proportional counting.

    PubMed

    Mace, Emily; Aalseth, Craig; Brandenberger, Jill; Day, Anthony; Hoppe, Eric; Humble, Paul; Keillor, Martin; Kulongoski, Justin; Overman, Cory; Panisko, Mark; Seifert, Allen; White, Signe; Wilcox Freeburg, Eric; Williams, Richard

    2016-12-21

    Argon-39 can be used as a tracer for age-dating glaciers, oceans, and more recently, groundwater. With a half-life of 269 years, (39)Ar fills an intermediate age range gap (50-1,000 years) not currently covered by other common groundwater tracers. Therefore, adding this tracer to the data suite for groundwater studies provides an important tool for improving our understanding of groundwater systems. We present the methods employed for arriving at an age-date for a given sample of argon degassed from groundwater.

  12. 187Re - 187Os Nuclear Geochronometry: A New Dating Method Applied to Old Ores

    NASA Astrophysics Data System (ADS)

    Roller, Goetz

    2015-04-01

    187Re - 187Os nuclear geochronometry is a newly developed dating method especially (but not only) for PGE hosting magmatic ore deposits. It combines ideas of nuclear astrophysics with geochronology. For this, the concept of sudden nucleosynthesis [1-3] is used to calculate so-called nucleogeochronometric Rhenium-Osmium two-point-isochrone (TPI) ages. Here, the method is applied to the Sudbury Igneous Complex (SIC) and the Stillwater Complex (SC), using a set of two nuclear geochronometers. They are named the BARBERTON ( Re/Os = 0.849, 187Os/186Os = 10.04 ± 0.015 [4]) and the IVREA (Re/Os = 0.951, 187Os/186Os = 1.9360 ± 0.0015 [5]) nuclear geochronometer. Calculated TPI ages are consistent with results from Sm-Nd geochronology, a previously published Re-Os Molybdenum age of 2740 ± 80 Ma for the G-chromitite of the SC [6] and a Re-Os isochrone age of 1689 ± 160 Ma for the Strathcona ores of the SIC [7]. This leads to an alternative explanation of the peculiar and enigmatic 187Os/186Osi isotopic signatures reported from both ore deposits. For example, for a TPI age of 2717 ± 100 Ma the Ultramafic Series of the SC contains both extremely low (subchrondritic) 187Os/186Osi ratios (187Os/186Osi = 0.125 ± 0.067) and extremely radiogenic isotopic signatures (187Os/186Osi = 6.55 ± 1.7, [6]) in mineral separates (chromites) and whole rock samples, respectively. Within the Strathcona ores of the SIC, even more pronounced radiogenic 187Os/186Os initial ratios can be calculated for TPI ages between 1586 ± 63 Ma (187Os/186Osi = 8.998 ± 0.045) and 1733 ± 84 Ma (187Os/186Osi = 8.901 ± 0.059). These results are in line with the recalculated Re-Os isochrone age of 1689 ± 160 Ma (187Os/186Osi = 8.8 ± 2.3 [7]). In the light of nuclear geochronometry, the occurrence of such peculiar isotopic 187Os/186Osi signatures within one and the same lithological horizon are plausible if explained by mingling of the two nucleogeochronometric (BARBERTON and IVREA) reservoirs containing

  13. Establishing ion ratio thresholds based on absolute peak area for absolute protein quantification using protein cleavage isotope dilution mass spectrometry.

    PubMed

    Loziuk, Philip L; Sederoff, Ronald R; Chiang, Vincent L; Muddiman, David C

    2014-11-07

    Quantitative mass spectrometry has become central to the field of proteomics and metabolomics. Selected reaction monitoring is a widely used method for the absolute quantification of proteins and metabolites. This method renders high specificity using several product ions measured simultaneously. With growing interest in quantification of molecular species in complex biological samples, confident identification and quantitation has been of particular concern. A method to confirm purity or contamination of product ion spectra has become necessary for achieving accurate and precise quantification. Ion abundance ratio assessments were introduced to alleviate some of these issues. Ion abundance ratios are based on the consistent relative abundance (RA) of specific product ions with respect to the total abundance of all product ions. To date, no standardized method of implementing ion abundance ratios has been established. Thresholds by which product ion contamination is confirmed vary widely and are often arbitrary. This study sought to establish criteria by which the relative abundance of product ions can be evaluated in an absolute quantification experiment. These findings suggest that evaluation of the absolute ion abundance for any given transition is necessary in order to effectively implement RA thresholds. Overall, the variation of the RA value was observed to be relatively constant beyond an absolute threshold ion abundance. Finally, these RA values were observed to fluctuate significantly over a 3 year period, suggesting that these values should be assessed as close as possible to the time at which data is collected for quantification.

  14. Chemical Principles Revisited: Archaeological Dating.

    ERIC Educational Resources Information Center

    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…

  15. An in-situ K-Ar isochron dating method for planetary landers using a spot-by-spot laser-ablation technique

    NASA Astrophysics Data System (ADS)

    Cho, Yuichiro; Sugita, Seiji; Miura, Yayoi N.; Okazaki, Ryuji; Iwata, Naoyoshi; Morota, Tomokatsu; Kameda, Shingo

    2016-09-01

    Age is essential information for interpreting the geologic record on planetary surfaces. Although crater counting has been widely used to estimate the planetary surface ages, crater chronology in the inner solar system is largely built on radiometric age data from limited sites on the Moon. This has resulted in major uncertainty in planetary chronology. Because opportunities for sample-return missions are limited, in-situ geochronology measurements from one-way lander/rover missions are extremely valuable. Here we developed an in-situ isochron-based dating method using the K-Ar system, with K and Ar in a single rock sample extracted locally by laser ablation and measured using laser-induced breakdown spectroscopy (LIBS) and a quadrupole mass spectrometer (QMS), respectively. We built an experimental system combining flight-equivalent instruments and measured K-Ar ages for mineral samples with known ages (~1.8 Ga) and K contents (1-8 wt%); we achieved precision of 20% except for a mineral with low mechanical strength. Furthermore, validation measurements with two natural rocks (gneiss slabs) obtained K-Ar isochron ages and initial 40Ar consistent with known values for both cases. This result supports that our LIBS-MS approach can derive both isochron ages and contributions of non-in situ radiogenic 40Ar from natural rocks. Error assessments suggest that the absolute ages of key geologic events including the Noachian/Hesperian- and the Hesperian/Amazonian-transition can be dated with 10-20% errors for a rock containing ~1 wt% K2O, greatly reducing the uncertainty of current crater chronology models on Mars.

  16. Absolute method for the assay of oleuropein in olive oils by atmospheric pressure chemical ionization tandem mass spectrometry.

    PubMed

    De Nino, Antonio; Di Donna, Leonardo; Mazzotti, Fabio; Muzzalupo, Enzo; Perri, Enzo; Sindona, Giovanni; Tagarelli, Antonio

    2005-09-15

    Oleuropein (OLP, 1), the active ingredient present (i) in food integrators extracted from olive leaves, (ii) in table olives, and (iii) in extra virgin olive oils is a nutraceutical whose health benefits have been widely documented. A new analytical method for its assay, which is based on the utilization of atmospheric pressure chemical ionization tandem mass spectrometry and on the use of a synthetic labeled analogue, the 4-trideuteriocarboxyoleuropein (2), as an internal standard, is presented. The results obtained with extra virgin olive oils from different cultivars and different Italian regions are discussed.

  17. Eddy current modeling by finite element method for evaluation of mechanical properties of the structure cracked in absolute probe

    NASA Astrophysics Data System (ADS)

    Harzallah, Salaheddine; Chabaat, Mohamed; Belgacem, Fethi Bin Muhammad

    2014-12-01

    In this paper, a nondestructive evaluation by sensor Eddy current is used as a tool to control cracks and micro-cracks in materials. A simulation by a numerical approach based on the finite element method is employed to detect cracks in materials and eventually to study their propagation using a crucial parameter such as a Stress Intensity Factor (SIF). This method has emerged as one of the most efficient techniques for prospecting cracks in materials, evaluating SIFs and analyzing crack's growth in the context of linear elastic fracture mechanics (LEFM). This technique uses extrapolation of displacements from results compared with those obtained by the integral interaction. On the other hand, crack's growth is analyzed as a model by combining the maximum circumferential stress criteria with the critical plane for predicting the direction of crack growth. Moreover, a constant crack growth increment is determined using the modified Paris's model. Furthermore, stress intensity factors needed for these models are calculated using the domain form of the J-integral interactions.

  18. Aplisulfamines, new sulfoxide-containing metabolites from an aplidium tunicate: absolute stereochemistry at chiral sulfur and carbon atoms assigned through an original combination of spectroscopic and computational methods.

    PubMed

    Aiello, Anna; Fattorusso, Ernesto; Imperatore, Concetta; Luciano, Paolo; Menna, Marialuisa; Vitalone, Rocco

    2012-01-01

    Two new sulfoxide-containing metabolites, aplisulfamines A and B, have been isolated from an Aplidium sp. collected in the Bay of Naples. Their planar structure and geometry of a double bond were readily determined by using standard methods, mainly NMR spectroscopy. An original approach was used to assign the absolute configuration at the three contiguous chiral centers present in the structures of both aplisulfamines, two at carbon and one at sulfur. This involved Electronic Circular Dichroism (ECD) studies, J-based configuration analysis and Density Functional Theory (DFT) calculations and represents an interesting integration of modern techniques in stereoanalysis, which could contribute to the enhancement of theoretical protocols recently applied to solve stereochemical aspects in structure elucidation.

  19. The 1H NMR method for the determination of the absolute configuration of 1,2,3-prim,sec,sec-triols.

    PubMed

    Lallana, Enrique; Freire, Félix; Seco, José Manuel; Quiñoa, Emilio; Riguera, Ricardo

    2006-09-28

    The absolute configuration of 1,2,3-prim,sec,sec-triols can be assigned by comparison of the 1H NMR spectra of the tris-(R)- and the tris-(S)-MPA ester derivatives. An experimental demonstration of this correlation with 24 triols of known absolute configuration and a protocol using two parameters-Deltadelta(RS)(H3) and the difference between Deltadelta RS (H2) and Deltadelta RS (H3) = absolute value (Delta(Deltadelta RS))-for its application to the determination of the absolute configuration of other triols are presented.

  20. The evolutionary relationships and age of Homo naledi: An assessment using dated Bayesian phylogenetic methods.

    PubMed

    Dembo, Mana; Radovčić, Davorka; Garvin, Heather M; Laird, Myra F; Schroeder, Lauren; Scott, Jill E; Brophy, Juliet; Ackermann, Rebecca R; Musiba, Chares M; de Ruiter, Darryl J; Mooers, Arne Ø; Collard, Mark

    2016-08-01

    Homo naledi is a recently discovered species of fossil hominin from South Africa. A considerable amount is already known about H. naledi but some important questions remain unanswered. Here we report a study that addressed two of them: "Where does H. naledi fit in the hominin evolutionary tree?" and "How old is it?" We used a large supermatrix of craniodental characters for both early and late hominin species and Bayesian phylogenetic techniques to carry out three analyses. First, we performed a dated Bayesian analysis to generate estimates of the evolutionary relationships of fossil hominins including H. naledi. Then we employed Bayes factor tests to compare the strength of support for hypotheses about the relationships of H. naledi suggested by the best-estimate trees. Lastly, we carried out a resampling analysis to assess the accuracy of the age estimate for H. naledi yielded by the dated Bayesian analysis. The analyses strongly supported the hypothesis that H. naledi forms a clade with the other Homo species and Australopithecus sediba. The analyses were more ambiguous regarding the position of H. naledi within the (Homo, Au. sediba) clade. A number of hypotheses were rejected, but several others were not. Based on the available craniodental data, Homo antecessor, Asian Homo erectus, Homo habilis, Homo floresiensis, Homo sapiens, and Au. sediba could all be the sister taxon of H. naledi. According to the dated Bayesian analysis, the most likely age for H. naledi is 912 ka. This age estimate was supported by the resampling analysis. Our findings have a number of implications. Most notably, they support the assignment of the new specimens to Homo, cast doubt on the claim that H. naledi is simply a variant of H. erectus, and suggest H. naledi is younger than has been previously proposed.

  1. History of the youngest members of the Valles Rhyolite, Valles caldera, New Mexico using ESR dating method

    SciTech Connect

    Ogoh, K; Toyoda, S; Ikeda, S; Ikeya, M; Goff, F

    1991-01-01

    The cooling history of the Valles caldera was studied by the electron spin resonance (ESR) dating method using Al and Ti centers in quartz grains which were separated from the youngest units of the Valles Rhyolite. The ESR apparent ages are much younger than fission track ages and {sup 39}Ar- {sup 40}Ar ages. Three possibilities are suggested, the first is that the ESR ages are real, the second is that ESR method did not work for these samples, and the third is that about 10--40 ka, the signal intensity was partially reduced by a thermal event such as proposed by Harrison et al. (1986). Research on the first and second possibilities is continuing. The third possibility might explain the difference between ESR ages and those by other methods (fission track and {sup 39}Ar- {sup 40}Ar). ESR dating has produced new insights regarding the history of the Valles caldera.

  2. Dating of Modern Human Evolution

    NASA Astrophysics Data System (ADS)

    Grun, R.

    Dating studies on palaoeanthropological sites is usually carried out on material associ- ated 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 fossils were discovered at a time when no careful excavations were carried out and it is impossible to correlate the specimen with other datable material (which applies tonearly 90% of all palaeoanthropological specimens). 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 ac- complished 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 exam

  3. LC-MS/MS methods for absolute quantification and identification of proteins associated with chimeric plant oil bodies.

    PubMed

    Capuano, Floriana; Bond, Nicholas J; Gatto, Laurent; Beaudoin, Frédéric; Napier, Johnathan A; Benvenuto, Eugenio; Lilley, Kathryn S; Baschieri, Selene

    2011-12-15

    Oil bodies (OBs) are plant cell organelles that consist of a lipid core surrounded by a phospholipid monolayer embedded with specialized proteins such as oleosins. Recombinant proteins expressed in plants can be targeted to OBs as fusions with oleosin. This expression strategy is attractive because OBs are easily enriched and purified from other cellular components, based on their unique physicochemical properties. For recombinant OBs to be a potential therapeutic agent in biomedical applications, it is necessary to comprehensively analyze and quantify both endogenous and heterologously expressed OB proteins. In this study, a mass spectrometry (MS)-based method was developed to accurately quantify an OB-targeted heterologously expressed fusion protein that has potential as a therapeutic agent. The effect of the chimeric oleosin expression upon the OB proteome in transgenic plants was also investigated, and the identification of new potential OB residents was pursued through a variety of liquid chromatography (LC)-MS/MS approaches. The results showed that the accumulation of the fusion protein on OBs was low. Moreover, no significant differences in the accumulation of OB proteins were revealed between transgenic and wild-type seeds. The identification of five new putative components of OB proteome was also reported.

  4. Potential and limitations of the ESR dating method applied to Lower Pleistocene epoch: some examples from Orce (Guadix-Baza basin, Andalusia, Spain)

    NASA Astrophysics Data System (ADS)

    Duval, Mathieu; Falguères, Christophe; Bahain, Jean-Jacques; Voinchet, Pierre; Grün, Rainer

    2010-05-01

    The range of absolute dating methods potentially applicable in archaeological and/or geological context appears quite limited for the Lower Pleistocene epoch. Indeed, their use is constrained by several factors such as the sedimentary context, the kind of material in situ available or the studied time range. Among these methods, Electron Spin Resonance (ESR) is undoubtedly the most commonly used for ancient archaeological sites, mainly because it can be applied to a large range of material: flowstone, sedimentary quartz and fossil teeth for example. The development of this method is therefore really crucial in order to complete the chronostratigraphical framework of the first human settlement in Europe. To illustrate this, we worked on several sites in the Guadix-Baza basin (Andalusia, Spain), one of the foremost places in Europe with evidence of early human occupation. The basin has accumulated a massive sequence of Neogen-Quaternary sediments which contains a detailed archive of palaeoenvironmental and palaeoclimatic changes since the Miocene. The numerous palaeontological remains discovered from more than a hundred sites, together with a well-defined magnetostratigraphical framework, have established the basin as a reference sequence for the European Pliocene-Quaternary period. The most famous Plio-Pleistocene localities are located in the eastern part of the basin, near the village of Orce. The sites of Fuente Nueva III and Barranco León have delivered an archaic lithic industry associated with Early Pleistocene fauna, indicating one of the oldest occupations of Western Europe. A third site, Venta Micena, which contained large and detailed palaeontological assemblages (several thousands of remains), has become a reference locality for the Early Pleistocene biochronology. The chronostratigraphical framework of these sites was established mainly by the combination of several methods: biochronology (small and large-mammals) and palaeomagnetism. In order to

  5. The effects of dual-domain mass transfer on the tritium-helium-3 dating method.

    PubMed

    Neumann, Rebecca B; Labolle, Eric M; Harvey, Charles F

    2008-07-01

    Diffusion of tritiated water (referred to as tritium) and helium-3 between mobile and immobile regions in aquifers (mass transfer) can affect tritium and helium-3 concentrations and hence tritium-helium-3 (3H/3He) ages that are used to estimate aquifer recharge and groundwater residence times. Tritium and helium-3 chromatographically separate during transport because their molecular diffusion coefficients differ. Simulations of tritium and helium-3 transport and diffusive mass transfer along stream tubes show that mass transfer can shift the 3H/3He age of the tritium and helium-3 concentration ([3H + 3He]) peak to dates much younger than the 1963 peak in atmospheric tritium. Furthermore, diffusive mass-transfer can cause the 3H/3He age to become younger downstream along a stream tube, even as the mean water-age must increase. Simulated patterns of [3H + 3He] versus 3H/3He age using a mass transfer model appear consistent with a variety of field data. These results suggest that diffusive mass transfer should be considered, especially when the [3H + 3He] peak is not well defined or appears younger than the atmospheric peak. 3H/3He data provide information about upstream mass-transfer processes that could be used to constrain mass-transfer models; however, uncritical acceptance of 3H/3He dates from aquifers with immobile regions could be misleading.

  6. Ages of Sevier thrusting from dating of metamorphic garnet using the Lu-Hf method

    NASA Astrophysics Data System (ADS)

    Cruz-Uribe, A. M.; Hoisch, T. D.; Wells, M. L.; Vervoort, J. D.

    2008-12-01

    Combined thermodynamic modeling of garnet growth zoning and Lu-Hf dating of garnet yield well-constrained pressure-temperature-time (PTt) paths. Here we present PTt paths from amphibolite-facies pelitic garnet from the Raft River-Albion-Grouse Creek metamorphic core complex that constrain the timing of thrusting in the hinterland of the Sevier thrust belt. Three general times of thrust burial are indicated: 150, 138, and 85 Ma. Lu-Hf garnet dating of burial-related garnet growth in the Raft River Mountains yielded a Late Jurassic age of 149.9 ± 1.2 Ma (2σ, MSWD = 1.1) based on three garnet fractions and a whole rock. A PT path from the schist of Mahogany Peaks in the Albion Range, Idaho, records an isothermal pressure increase indicating growth during thrusting. Lu-Hf dating of garnet from the same rock yielded an Early Cretaceous age of 138.7 ± 0.7 Ma (2σ, MSWD = 1.6) based on seven garnet fractions. An additional PT path from a nearby outcrop also records an isothermal pressure increase and a similar Lu-Hf garnet age of 132.1 ± 5.1 Ma (2σ, MSWD = 9.5) based on three garnet fractions and a whole rock. PT paths of multiple garnet grains from the schist of Stevens Spring in the Grouse Creek Mountains, Utah, exhibit isothermal pressure increases and yielded a Lu-Hf garnet age of 85.5 ± 1.9 Ma (2σ, MSWD = 3.9) based on five garnet fractions and a whole rock. The Late Jurassic burial event recorded in the Raft River Mountains is older than the ages of inception of thrusting of the western thrusts of the Sevier fold-thrust belt including the Canyon Range and Paris - Willard thrusts, but consistent with an eastward progression in initial shortening in the orogenic wedge and development of an inferred thrust load responsible for the retroarc Morrison Formation basin. Early Cretaceous hinterland burial recorded in the Albion Range is permissively coeval with activity on the Willard and Canyon Range thrusts. Finally, renewed hinterland thrust burial during the Late

  7. Diachroneity of the Clearwater West and Clearwater East impact structures indicated by the (U-Th)/He dating method

    NASA Astrophysics Data System (ADS)

    Biren, M. B.; van Soest, M. C.; Wartho, J.-A.; Hodges, K. V.; Spray, J. G.

    2016-11-01

    The (U-Th)/He method has been applied to constrain the formation ages of the Clearwater West and East impact structures of Quebec, Canada. Zircons were separated from impact melt samples derived from a surface exposure at Clearwater West (32 km diameter), and from a drill core at Clearwater East (26 km diameter). The (U-Th)/He results indicate ages of 280 ± 27 Ma (2σ, n = 7) for Clearwater West, and 450 ± 56 Ma (2σ, n = 8) for Clearwater East. Our (U-Th)/He date for Clearwater West supports the findings of previous Rb-Sr (266 ± 15 Ma; 2σ) and 40Ar/39Ar (280 ± 4 Ma and 283.8 ± 2.2 Ma, 2σ) impact melt studies. Our (U-Th)/He date for Clearwater East also overlaps with previously published 40Ar/39Ar dating results, which yielded U-shaped spectra, with 'maximum' and 'best-estimate' dates of ∼ 460-470 Ma. Our results support the contention, previously based solely on 40Ar/39Ar data, that the Clearwater West and East impact structures do not comprise an impact doublet that formed coevally from a binary asteroid pair.

  8. Dating of seals produced with stamp-pad ink using gas chromatography method.

    PubMed

    Li, Biao

    2014-09-01

    Seals are often placed on important documents, and determining the date when a seal was affixed can be important to assess the authenticity of a document. In this study, thirty-seven different brands of stamp-pad inks and three different types of paper were used to make diachronic samples of the seals. The volatile components of stamp-pad ink were determined, and the stamp-pad ink was classified by gas chromatography with a flame ionization detector. Calibration curves were created to show the relationship between the content of volatile stamp-pad ink components and the age of stamp-pad ink entries stored under natural aging, UV-induced aging, and heating aging conditions. The experimental results showed that GC was useful in the analysis of stamp-pad ink and applicable for determining the relative age of stamp-pad ink entries in some cases where the seal was placed on the document within 3 months.

  9. Comparing paired vs non-paired statistical methods of analyses when making inferences about absolute risk reductions in propensity-score matched samples.

    PubMed

    Austin, Peter C

    2011-05-20

    Propensity-score matching allows one to reduce the effects of treatment-selection bias or confounding when estimating the effects of treatments when using observational data. Some authors have suggested that methods of inference appropriate for independent samples can be used for assessing the statistical significance of treatment effects when using propensity-score matching. Indeed, many authors in the applied medical literature use methods for independent samples when making inferences about treatment effects using propensity-score matched samples. Dichotomous outcomes are common in healthcare research. In this study, we used Monte Carlo simulations to examine the effect on inferences about risk differences (or absolute risk reductions) when statistical methods for independent samples are used compared with when statistical methods for paired samples are used in propensity-score matched samples. We found that compared with using methods for independent samples, the use of methods for paired samples resulted in: (i) empirical type I error rates that were closer to the advertised rate; (ii) empirical coverage rates of 95 per cent confidence intervals that were closer to the advertised rate; (iii) narrower 95 per cent confidence intervals; and (iv) estimated standard errors that more closely reflected the sampling variability of the estimated risk difference. Differences between the empirical and advertised performance of methods for independent samples were greater when the treatment-selection process was stronger compared with when treatment-selection process was weaker. We recommend using statistical methods for paired samples when using propensity-score matched samples for making inferences on the effect of treatment on the reduction in the probability of an event occurring.

  10. Dating open systems by the 238U- 234U- 230Th method: application to Quaternary reef terraces

    NASA Astrophysics Data System (ADS)

    Villemant, B.; Feuillet, N.

    2003-05-01

    The sedimentation conditions and diagenetic processes of biogenic and inorganic carbonates are such that the assumptions of a closed system evolution and the absence of initial Th invoked in classical 238U- 234U- 230Th dating methods are very often not fulfilled for such material. This problem is of interest for all studies requiring accurate dating of corals or aragonite-rich sediments as in palaeoclimatology or neotectonics. Extending the approach of Henderson and Slowey [Nature 404 (2000) 61-66], we propose a consistent model that takes into account possible initial 230Th excess and where continuous selective redistribution (gain or loss) of 234U, 234Th and 230Th is controlled by recoil processes. This model applied to Quaternary marine terraces in Barbados, Marie Galante (Lesser Antilles arc) and Pacific islands, is able to explain the large scatter in isotopic compositions observed in the series of cogenetic corals or sediments. We show that recoil processes generally tend to increase the ( 234U/ 238U) and ( 230Th/ 234U) ratios with time, leading to an overestimation of the apparent ages calculated using classical methods. On the basis of simple assumptions (identical 'marine' initial ( 234U/ 238U) 0 and ( 230Th/ 232Th) 0 ratios), we propose a method for calculating a best estimate of the age of cogenetic series. Our model offers an alternative way to date old reef terraces where corals are almost systematically altered and where classical dating methods do not apply. It may also explain the apparent variations of the ( 234U/ 238U) seawater initial ratio estimated from corals formed in the last 300 ka and the apparent uncoupling between sea-level highstands and high-latitude Northern Hemisphere summer insolation. Our set of equations can be applied to all weathering processes where the mobility of U-series isotopes is controlled by recoil.

  11. Meteorite bombardment and dating of planetary surfaces. Thesis - Feb. 1983

    NASA Technical Reports Server (NTRS)

    Neukum, G.

    1984-01-01

    Dating by measurement of impact crater frequencies developed in the past years primarily on the basis of the data from the missions to the Moon and Mars. The method allows a good relative dating to be obtained and the moons of Jupiter and Saturn through photographic analyses. A cratering chronology was obtained for the period between the oldest Moon crust (4.3 to 4.4 billion years) to the present time which gives a good absolute dating of any areas of the Moon's surface.

  12. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  13. A simple method for DNA extraction from mature date palm leaves: impact of sand grinding and composition of lysis buffer.

    PubMed

    Arif, Ibrahim A; Bakir, Mohammad A; Khan, Haseeb A; Ahamed, Anis; Al Farhan, Ahmad H; Al Homaidan, Ali A; Al Sadoon, Mohammad; Bahkali, Ali H; Shobrak, Mohammad

    2010-09-08

    Molecular marker techniques have been widely used for cultivar identification of inbred date palms (Phoenix dactylifera L.; Arecaceae) and biodiversity conservation. Isolation of highly pure DNA is the prerequisite for PCR amplification and subsequent use such as DNA fingerprinting and sequencing of genes that have recently been developed for barcoding. To avoid problems related to the preservation and use of liquid nitrogen, we examined sterile sand for grinding the date palm leaves. Individual and combined effects of sodium chloride (NaCl), polyvinylpyrrolidone (PVP) and lithium chloride (LiCl) with the cetyltrimethylammonium bromide (CTAB) method for a DNA yield of sufficient purity and PCR amplification were evaluated in this study. Presence of LiCl and PVP alone or together in the lysis buffer did not significantly improve the DNA yield and purity compared with the addition of NaCl. Our study suggested that grinding of date palm leaf with sterile sand and inclusion of NaCl (1.4 M) in the lysis buffer without the costly use of liquid nitrogen, PVP and LiCl, provides a DNA yield of sufficient purity, suitable for PCR amplification.

  14. Absolute and relative blindsight.

    PubMed

    Balsdon, Tarryn; Azzopardi, Paul

    2015-03-01

    The concept of relative blindsight, referring to a difference in conscious awareness between conditions otherwise matched for performance, was introduced by Lau and Passingham (2006) as a way of identifying the neural correlates of consciousness (NCC) in fMRI experiments. By analogy, absolute blindsight refers to a difference between performance and awareness regardless of whether it is possible to match performance across conditions. Here, we address the question of whether relative and absolute blindsight in normal observers can be accounted for by response bias. In our replication of Lau and Passingham's experiment, the relative blindsight effect was abolished when performance was assessed by means of a bias-free 2AFC task or when the criterion for awareness was varied. Furthermore, there was no evidence of either relative or absolute blindsight when both performance and awareness were assessed with bias-free measures derived from confidence ratings using signal detection theory. This suggests that both relative and absolute blindsight in normal observers amount to no more than variations in response bias in the assessment of performance and awareness. Consideration of the properties of psychometric functions reveals a number of ways in which relative and absolute blindsight could arise trivially and elucidates a basis for the distinction between Type 1 and Type 2 blindsight.

  15. A new method for calculating the accumulated dose in ESR dating and retrospective dosimetry.

    PubMed

    Oliveira, Luiz Carlos; Kinoshita, Angela; Lopes, Renato P; Baffa, Oswaldo

    2010-02-01

    Dose evaluation by electron spin resonance (ESR) is usually accomplished by constructing a dose-response curve by measuring the peak-to-peak intensity of the dosimetric signals in the g = 2 region. In several cases, this signal is overlapped with others that can interfere with dose reconstruction. In this work a new method to correct the spectrum before the measurement of the signal intensity is proposed. Examples of dose determination of accumulated dose (AD) of two fossil teeth from southern Brazilian megafauna are given. One of them presents a dose-independent signal in the region of interest, and the validity of this method is shown. For the other, without interfering signals, no difference in the AD was found. This method can also be applied to retrospective dosimetry by ESR for any sample with dose-independent interfering signals, thus improving the accuracy in AD determination by ESR.

  16. Lower and upper bounds for the absolute free energy by the hypothetical scanning Monte Carlo method: application to liquid argon and water.

    PubMed

    White, Ronald P; Meirovitch, Hagai

    2004-12-08

    The hypothetical scanning (HS) method is a general approach for calculating the absolute entropy S and free energy F by analyzing Boltzmann samples obtained by Monte Carlo or molecular dynamics techniques. With HS applied to a fluid, each configuration i of the sample is reconstructed by gradually placing the molecules in their positions at i using transition probabilities (TPs). At each step of the process the system is divided into two parts, the already treated molecules (the "past"), which are fixed, and the as yet unspecified (mobile) "future" molecules. Obtaining the TP exactly requires calculating partition functions over all positions of the future molecules in the presence of the frozen past, thus it is customary to invoke various approximations to best represent these quantities. In a recent publication [Proc. Natl. Acad. Sci. USA 101, 9235 (2004)] we developed a version of HS called complete HSMC, where each TP is calculated from an MC simulation involving all of the future molecules (the complete future); the method was applied very successfully to Lennard-Jones systems (liquid argon) and a box of TIP3P water molecules. In its basic implementation the method provides lower and upper bounds for F, where the latter can be evaluated only for relatively small systems. Here we introduce a new expression for an upper bound, which can be evaluated for larger systems. We also propose a new exact expression for F and verify its effectiveness. These free energy functionals lead to significantly improved accuracy (as applied to the liquid systems above) which is comparable to our thermodynamic integration results. We formalize and discuss theoretical aspects of HSMC that have not been addressed in previous studies. Additionally, several functionals are developed and shown to provide the free energy through the analysis of a single configuration.

  17. Radioactive fallouts as temporal makers for glacier ice cores dating

    NASA Astrophysics Data System (ADS)

    Clemenza, M.; Cucciati, G.; Maggi, V.; Pattavina, L.; Previtali, E.

    2012-06-01

    In this paper, we intend to show how analytical methods used in nuclear physics, as gamma spectroscopy, are powerful tools for the dating of environmental archives. Specifically, we will show how events related to the release in the environment of great amount of radioactive isotopes ( e.g., atmospheric nuclear test explosions) can be used as temporal markers in alpine glaciers. The radio-isotope selected for the dating of ice carrots is 137Cs , because of its chemical and nuclear properties. The radioactive measurements have been conducted using a low-background high-purity germanium detector. The sensitivity for the prepared samples is 10mBq/kg. We will illustrate how dating curves (date versus depth of the sample) can be considered as an absolute calibrator for all the other chemical dating methods used on glacier samples analyses.

  18. Absolute neutrino mass scale

    NASA Astrophysics Data System (ADS)

    Capelli, Silvia; Di Bari, Pasquale

    2013-04-01

    Neutrino oscillation experiments firmly established non-vanishing neutrino masses, a result that can be regarded as a strong motivation to extend the Standard Model. In spite of being the lightest massive particles, neutrinos likely represent an important bridge to new physics at very high energies and offer new opportunities to address some of the current cosmological puzzles, such as the matter-antimatter asymmetry of the Universe and Dark Matter. In this context, the determination of the absolute neutrino mass scale is a key issue within modern High Energy Physics. The talks in this parallel session well describe the current exciting experimental activity aiming to determining the absolute neutrino mass scale and offer an overview of a few models beyond the Standard Model that have been proposed in order to explain the neutrino masses giving a prediction for the absolute neutrino mass scale and solving the cosmological puzzles.

  19. Dating human skeletal remains using a radiometric method: biogenic versus diagenetic 90Sr and 210Pb in vertebrae.

    PubMed

    Schrag, Bettina; Uldin, Tanya; Mangin, Patrice; Froidevaux, Pascal

    2012-07-10

    In forensic science, there is a strong interest in determining the post-mortem interval (PMI) of human skeletal remains up to 50 years after death. Currently, there are no reliable methods to resolve PMI, the determination of which relies almost exclusively on the experience of the investigating expert. Here we measured (90)Sr and (210)Pb ((210)Po) incorporated into bones through a biogenic process as indicators of the time elapsed since death. We hypothesised that the activity of radionuclides incorporated into trabecular bone will more accurately match the activity in the environment and the food chain at the time of death than the activity in cortical bone because of a higher remodelling rate. We found that determining (90)Sr can yield reliable PMI estimates as long as a calibration curve exists for (90)Sr covering the studied area and the last 50 years. We also found that adding the activity of (210)Po, a proxy for naturally occurring (210)Pb incorporated through ingestion, to the (90)Sr dating increases the reliability of the PMI value. Our results also show that trabecular bone is subject to both (90)Sr and (210)Po diagenesis. Accordingly, we used a solubility profile method to determine the biogenic radionuclide only, and we are proposing a new method of bone decontamination to be used prior to (90)Sr and (210)Pb dating.

  20. Comparison of manual and automated pretreatment methods for AMS radiocarbon dating of plant fossils

    USGS Publications Warehouse

    Bradley, L.-A.; Stafford, Thomas W.

    1994-01-01

    A new automated pretreatment system for the preparation of materials submitted for accelerator mass spectrometry (AMS) analysis is less time-consuming and results in a higher sample yield. The new procedure was tested using two groups of plant fossils: one group was pretreated using the traditional method, and the second, using the automated pretreatment apparatus. The time it took to complete the procedure and the amount of sample material remaining were compared. The automated pretreatment apparatus proved to be more than three times faster and, in most cases, produced a higher yield. A darker discoloration of the KOH solutions was observed indicating that the automated system is more thorough in removing humates from the specimen compared to the manual method. -Authors

  1. Radiocarbon Dating

    SciTech Connect

    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.

  2. The absolute path command

    SciTech Connect

    Moody, A.

    2012-05-11

    The ap command traveres all symlinks in a given file, directory, or executable name to identify the final absolute path. It can print just the final path, each intermediate link along with the symlink chan, and the permissions and ownership of each directory component in the final path. It has functionality similar to "which", except that it shows the final path instead of the first path. It is also similar to "pwd", but it can provide the absolute path to a relative directory from the current working directory.

  3. Dating Violence

    ERIC Educational Resources Information Center

    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…

  4. A method for determining weights for excess relative risk and excess absolute risk when applied in the calculation of lifetime risk of cancer from radiation exposure.

    PubMed

    Walsh, Linda; Schneider, Uwe

    2013-03-01

    Radiation-related risks of cancer can be transported from one population to another population at risk, for the purpose of calculating lifetime risks from radiation exposure. Transfer via excess relative risks (ERR) or excess absolute risks (EAR) or a mixture of both (i.e., from the life span study (LSS) of Japanese atomic bomb survivors) has been done in the past based on qualitative weighting. Consequently, the values of the weights applied and the method of application of the weights (i.e., as additive or geometric weighted means) have varied both between reports produced at different times by the same regulatory body and also between reports produced at similar times by different regulatory bodies. Since the gender and age patterns are often markedly different between EAR and ERR models, it is useful to have an evidence-based method for determining the relative goodness of fit of such models to the data. This paper identifies a method, using Akaike model weights, which could aid expert judgment and be applied to help to achieve consistency of approach and quantitative evidence-based results in future health risk assessments. The results of applying this method to recent LSS cancer incidence models are that the relative EAR weighting by cancer solid cancer site, on a scale of 0-1, is zero for breast and colon, 0.02 for all solid, 0.03 for lung, 0.08 for liver, 0.15 for thyroid, 0.18 for bladder and 0.93 for stomach. The EAR weighting for female breast cancer increases from 0 to 0.3, if a generally observed change in the trend between female age-specific breast cancer incidence rates and attained age, associated with menopause, is accounted for in the EAR model. Application of this method to preferred models from a study of multi-model inference from many models fitted to the LSS leukemia mortality data, results in an EAR weighting of 0. From these results it can be seen that lifetime risk transfer is most highly weighted by EAR only for stomach cancer. However

  5. Radiometric Dating Does Work!

    ERIC Educational Resources Information Center

    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)

  6. A graphical method to evaluate predominant geochemical processes occurring in groundwater systems for radiocarbon dating

    USGS Publications Warehouse

    Han, Liang-Feng; Plummer, L. Niel; Aggarwal, Pradeep

    2012-01-01

    A graphical method is described for identifying geochemical reactions needed in the interpretation of radiocarbon age in groundwater systems. Graphs are constructed by plotting the measured 14C, δ13C, and concentration of dissolved inorganic carbon and are interpreted according to specific criteria to recognize water samples that are consistent with a wide range of processes, including geochemical reactions, carbon isotopic exchange, 14C decay, and mixing of waters. The graphs are used to provide a qualitative estimate of radiocarbon age, to deduce the hydrochemical complexity of a groundwater system, and to compare samples from different groundwater systems. Graphs of chemical and isotopic data from a series of previously-published groundwater studies are used to demonstrate the utility of the approach. Ultimately, the information derived from the graphs is used to improve geochemical models for adjustment of radiocarbon ages in groundwater systems.

  7. Absolute quantitation of protein posttranslational modification isoform.

    PubMed

    Yang, Zhu; Li, Ning

    2015-01-01

    Mass spectrometry has been widely applied in characterization and quantification of proteins from complex biological samples. Because the numbers of absolute amounts of proteins are needed in construction of mathematical models for molecular systems of various biological phenotypes and phenomena, a number of quantitative proteomic methods have been adopted to measure absolute quantities of proteins using mass spectrometry. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with internal peptide standards, i.e., the stable isotope-coded peptide dilution series, which was originated from the field of analytical chemistry, becomes a widely applied method in absolute quantitative proteomics research. This approach provides more and more absolute protein quantitation results of high confidence. As quantitative study of posttranslational modification (PTM) that modulates the biological activity of proteins is crucial for biological science and each isoform may contribute a unique biological function, degradation, and/or subcellular location, the absolute quantitation of protein PTM isoforms has become more relevant to its biological significance. In order to obtain the absolute cellular amount of a PTM isoform of a protein accurately, impacts of protein fractionation, protein enrichment, and proteolytic digestion yield should be taken into consideration and those effects before differentially stable isotope-coded PTM peptide standards are spiked into sample peptides have to be corrected. Assisted with stable isotope-labeled peptide standards, the absolute quantitation of isoforms of posttranslationally modified protein (AQUIP) method takes all these factors into account and determines the absolute amount of a protein PTM isoform from the absolute amount of the protein of interest and the PTM occupancy at the site of the protein. The absolute amount of the protein of interest is inferred by quantifying both the absolute amounts of a few PTM

  8. An up-to-date overview of minimally invasive treatment methods in ureteropelvic junction obstruction

    PubMed Central

    Celik, Orcun; Ilbey, Yusuf Ozlem

    2015-01-01

    Introduction Over the last two decades, minimally invasive treatment options for ureteropelvic junction obstruction have been developed and are bcoming more popular. Multiple series of laparoscopic pyeloplasty have demonstrated high success rates and low perioperative morbidity in pediatric and adult populations, for both the transperitoneal and retroperitoneal approaches. In this review, we aimed to analyze the current status of minimally invasive therapy of ureteropelvic junction obstruction. Material and methods A PubMed database search was conducted to examine minimally invasive treatments of ureteropelvic junction obstruction. Results A large number of cases have been reported for adult patients, confirming that robotic pyeloplasty represents a viable option for either primary or secondary repair. Comparative studies demonstrate similar success and complication rates between minimally invasive and open pyeloplasty in both the adult and pediatric populations. A clear advantage, in terms of hospital stay, of minimally invasive over open pyeloplasty was observed only in the adult population. Conclusions Studies have shown that minimally invasive pyeloplasty techniques are a safe, effective, and feasible in adult and pediatric populations. PMID:26251754

  9. Development and Validation of an HPLC-UV Method for Determination of Eight Phenolic Compounds in Date Palms.

    PubMed

    Al-Rimawi, Fuad; Odeh, Imad

    2015-01-01

    A simple, precise, accurate, and selective method was developed and validated for determination of eight phenolic compounds (gallic acid, p-hydroxybenzoic acid, vanilic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, and sinapic acid) in date palms. Separation was achieved on an RP C18 column using the mobile phase methanol-water with 2% acetic acid (18+82, v/v). This method was validated according to the requirements for new methods, which include accuracy, precision, selectivity, robustness, LOD, LOQ, linearity, and range. The method demonstrated good linearity over the range 1-1000 ppm of gallic acid, p-hydroxybenzoic acid, vanilic acid, caffeic acid, and syringic acid with r2 greater than 0.99, and in the range of 3-1000 ppm for p-coumaric acid, ferulic acid, and sinapic acid with r2 greater than 0.99. The recovery of the eight phenolic compounds ranged from 97.1 to 102.2%. The method is selective because adjacent peaks of phenolic compounds were well separated with good resolution. The degree of reproducibility of the results obtained as a result of small deliberate variations in the method parameters and by changing analytical operators proved that the method is robust and rugged.

  10. Absolute entropy and free energy of fluids using the hypothetical scanning method. II. Transition probabilities from canonical Monte Carlo simulations of partial systems

    NASA Astrophysics Data System (ADS)

    White, Ronald P.; Meirovitch, Hagai

    2003-12-01

    A variant of the hypothetical scanning (HS) method for calculating the absolute entropy and free energy of fluids is developed, as applied to systems of Lennard-Jones atoms (liquid argon). As in the preceding paper (Paper I), a probability Pi approximating the Boltzmann probability of system configuration i, is calculated with a reconstruction procedure based on adding the atoms gradually to an initially empty volume, where they are placed in their positions at i; in this process the volume is divided into cubic cells, which are visited layer-by-layer, line-by-line. At each step a transition probability (TP) is calculated and the product of all the TPs leads to Pi. At step k, k-1 cells have already been treated, where among them Nk are occupied by an atom. A canonical metropolis Monte Carlo (MC) simulation is carried out over a portion of the still unvisited (future) volume thus providing an approximate representation of the N-Nk as yet untreated (future) atoms. The TP of target cell k is determined from the number of visits of future atoms to this cell during the simulation. This MC version of HS, called HSMC, is based on a relatively small number of efficiency parameters; their number does not grow and their values are not changed as the number of the treated future atoms is increased (i.e., as the approximation improves); therefore, implementing HSMC for a relatively large number of future atoms (up to 40 in this study) is straightforward. Indeed, excellent results have been obtained for the free energy and the entropy.

  11. Calculation of the Absolute Free Energy of Binding and Related Entropies with the HSMD-TI Method: The FKBP12-L8 Complex.

    PubMed

    General, Ignacio J; Dragomirova, Ralitsa; Meirovitch, Hagai

    2011-10-27

    The hypothetical scanning molecular dynamics (HSMD) method is used here for calculating the absolute free energy of binding, ΔA(0) of the complex of the protein FKBP12 with the ligand SB2 (also denoted L8) - a system that has been studied previously for comparing the performance of different methods. Our preliminary study suggests that considering long-range electrostatics is imperative even for a hydrophobic ligand such as L8. Therefore the system is modeled by the AMBER force field using Particle Mesh Ewald (PME). HSMD consists of three stages applied to both the ligand-solvent and ligand-protein systems. (1) A small set of system configurations (frames) is extracted from an MD trajectory. (2) The entropy of the ligand in each frame is calculated by a reconstruction procedure. (3) The contribution of water and protein to ΔA(0) is calculated for each frame by gradually increasing the ligand-environment interactions from zero to their full value using thermodynamic integration (TI). Unlike the conventional methods, the structure of the ligand is kept fixed during TI, and HSMD is thus free from the end-point problem encountered with the double annihilation method (DAM); therefore, the need for applying restraints is avoided. Furthermore, unlike the conventional methods, the entropy of the ligand and water is obtained directly as a byproduct of the simulation. In this paper, in addition to the difference in the internal entropies of the ligand in the two environments, we calculate for the first time the external entropy of the ligand, which provides a measure for the size of the active site. We obtain ΔA(0) = -10.7 ±1.0 as compared to the experimental values -10.9 and -10.6 kcal/mol. However, a protein/water system treated by periodic boundary conditions grows significantly with increasing protein size and the computation of ΔA(0) would become expensive by all methods. Therefore, we also apply HSMD to FKBP12-L8 described by the GSBP/SSBP model of Roux's group

  12. Absolute realization of low BRDF value

    NASA Astrophysics Data System (ADS)

    Liu, Zilong; Liao, Ningfang; Li, Ping; Wang, Yu

    2010-10-01

    Low BRDF value is widespread used in many critical domains such as space and military fairs. These values below 0.1 Sr-1 . So the Absolute realization of these value is the most critical issue in the absolute measurement of BRDF. To develop the Absolute value realization theory of BRDF , defining an arithmetic operators of BRDF , achieving an absolute measurement Eq. of BRDF based on radiance. This is a new theory method to solve the realization problem of low BRDF value. This theory method is realized on a self-designed common double orientation structure in space. By designing an adding structure to extend the range of the measurement system and a control and processing software, Absolute realization of low BRDF value is achieved. A material of low BRDF value is measured in this measurement system and the spectral BRDF value are showed within different angles allover the space. All these values are below 0.4 Sr-1 . This process is a representative procedure about the measurement of low BRDF value. A corresponding uncertainty analysis of this measurement data is given depend on the new theory of absolute realization and the performance of the measurement system. The relative expand uncertainty of the measurement data is 0.078. This uncertainty analysis is suitable for all measurements using the new theory of absolute realization and the corresponding measurement system.

  13. Effects of Mentoring Speed Dating as an Innovative Matching Tool in Undergraduate Medical Education: A Mixed Methods Study

    PubMed Central

    Guse, Jennifer; Schweigert, Eva; Kulms, Gerhild; Heinen, Ines; Martens, Claudia; Guse, Andreas H.

    2016-01-01

    Objectives Choosing the right mentor is crucial for effective mentorship. Yet, many medical students have difficulties finding a suitable mentor. Thus we developed mentoring speed dating (MSD) as a promising matching tool to connect students and faculty mentors successfully. The purpose of this study was to explore mentees’ and mentors’ experience with MSD and investigate the impact of MSD on the perceived mentorship quality and continuance of the mentoring relationship. Methods The authors completed a mixed methods study at the University Medical Center Hamburg-Eppendorf, Germany, between June 2011 and March 2014. They conducted four focus groups with mentees and mentors who participated in a mentoring speed dating event and analyzed transcripts using conventional content analysis with inductive categorizing. In addition, three mentoring cohorts (two matched via MSD, one matched via conventional online profiles) were surveyed on mentorship satisfaction and the 1-year continuance of their mentorship was monitored. Fifteen mentees and fifteen mentors participated in the focus groups. The authors identified several themes such as short and long term benefits of MSD and fulfillment of expectations. Benefits included finding out about the personal connection, matching expectations, providing an efficient overview of candidates. The survey was completed by 93 students (n = 29 without MSD; n = 64 with MSD). Independent t-tests and multivariate analysis of variance were used to analyze the impact of MSD on student’s mentorship satisfaction. Results There were significant differences in responses to the items “Commitment of mentor” (p = .019) and “Constructive feedback” (p = .038) among the students who attended MSD and the students without MSD. After one year far more mentoring relationships existed among those mentees who participated in MSD in comparison to the “no MSD group”. Conclusion MSD is a valuable matching tool with beneficial effects on the

  14. A simple-rapid method to separate uranium, thorium, and protactinium for U-series age-dating of materials.

    PubMed

    Knight, Andrew W; Eitrheim, Eric S; Nelson, Andrew W; Nelson, Steven; Schultz, Michael K

    2014-08-01

    Uranium-series dating techniques require the isolation of radionuclides in high yields and in fractions free of impurities. Within this context, we describe a novel-rapid method for the separation and purification of U, Th, and Pa. The method takes advantage of differences in the chemistry of U, Th, and Pa, utilizing a commercially-available extraction chromatographic resin (TEVA) and standard reagents. The elution behavior of U, Th, and Pa were optimized using liquid scintillation counting techniques and fractional purity was evaluated by alpha-spectrometry. The overall method was further assessed by isotope dilution alpha-spectrometry for the preliminary age determination of an ancient carbonate sample obtained from the Lake Bonneville site in western Utah (United States). Preliminary evaluations of the method produced elemental purity of greater than 99.99% and radiochemical recoveries exceeding 90% for U and Th and 85% for Pa. Excellent purity and yields (76% for U, 96% for Th and 55% for Pa) were also obtained for the analysis of the carbonate samples and the preliminary Pa and Th ages of about 39,000 years before present are consistent with (14)C-derived age of the material.

  15. Comparison of gestational dating methods and implications for exposure-outcome associations: an example with PM2.5 and preterm birth

    EPA Science Inventory

    OBJECTIVES: Estimating gestational age is usually based on date of last menstrual period (LMP) or clinical estimation (CE); both approaches introduce potential bias. Differences in methods of estimation may lead to misclassificat ion and inconsistencies in risk estimates, particu...

  16. Quantyfing the global lightning activity in absolute unints using Schumann resonance spectral decomposition method and the data from the World ELF Radiolocation Array

    NASA Astrophysics Data System (ADS)

    Dyrda, M.; Kulak, A.; Mlynarczyk, J.; Ostrowski, M.

    2015-12-01

    The extremely low frequency (ELF) electromagnetic waves in the Earth-ionosphere cavity are generated mainly by lightning discharges, originating from the tropical thunderstorm centers. The Earth-ionosphere spherical cavity forms a global resonator for the ELF waves. In a spherical damped resonator, like the Earth-ionosphere cavity, the electromagnetic field is the superposition of the standing wave (resonance) field with the traveling waves field, which transfers the energy from lightning flashes to the global resonator. This component is quite strong close to the source and weakens with source-observer separation and is a major reason for an asymmetric shape of the observational Schumann resonance (SR) power spectra. In physics the process, where the resonant field interference with the background is very well known and in such a case the resonant lines are always asymmetric. However, it is possible to separate the resonance field component from the signal using the spectrum decomposition method proposed by Kułak et al. [2006]. Here, we examine the activity of African thunderstorm center using Schumann resonance data collected by the two ELF stations built under the World ELF Radiolocation Array (WERA) project. The first ELF station in located in Poland and it has been recording data continuously since the end of 2004. In May 2015, another ELF station was installed in the Hugo Wildlife Area in Colorado as part of our project WERA. We binned the ELF data in 10-minute files and we derived the SR power spectra. In the next step the decomposition curve, which describes 7 asymmetric SR modes was fitted to the observational data. Using the algorithm, described in Dyrda et al. [2014], we calculated the distances to the tropical thunderstorm center located in Africa with the spatial resolution of 0.1 Mm. This is done independently for each of the ELF stations from WERA array. Then using the information about the distances and about the size of our magnetic antennas beam

  17. Radiocarbon Dating, Memories, and Hopes

    DOE R&D Accomplishments Database

    Libby, W. F.

    1972-10-01

    The history of radiocarbon dating from 1939 to the present is reviewed. The basic principles of radiocarbon dating are that cosmic rays make living things radioactive with {sup 14}C to a certain level fixed by the environment and that at death the intake of food stops so no replenishment of the {sup 14}C steadily lost by the immutable decay occurs. Therefore measurement of the degree of decay gives the time lapse since death, i.e., the radiocarbon age. The equipment developed and experiments performed to measure the specific activity of specimens to be dated are described. The results obtained by world-wide experimenters are discussed. These showed that on simultaneity radiocarbon dating is apparently reliable but that absolute dates may be incorrect by as much as 600 to 700 y. The value of radiocarbon dating to archaeologists, geologists, climatologists, and historians is stressed. (LCL)

  18. Electronic Absolute Cartesian Autocollimator

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B.

    2006-01-01

    An electronic absolute Cartesian autocollimator performs the same basic optical function as does a conventional all-optical or a conventional electronic autocollimator but differs in the nature of its optical target and the manner in which the position of the image of the target is measured. The term absolute in the name of this apparatus reflects the nature of the position measurement, which, unlike in a conventional electronic autocollimator, is based absolutely on the position of the image rather than on an assumed proportionality between the position and the levels of processed analog electronic signals. The term Cartesian in the name of this apparatus reflects the nature of its optical target. Figure 1 depicts the electronic functional blocks of an electronic absolute Cartesian autocollimator along with its basic optical layout, which is the same as that of a conventional autocollimator. Referring first to the optical layout and functions only, this or any autocollimator is used to measure the compound angular deviation of a flat datum mirror with respect to the optical axis of the autocollimator itself. The optical components include an illuminated target, a beam splitter, an objective or collimating lens, and a viewer or detector (described in more detail below) at a viewing plane. The target and the viewing planes are focal planes of the lens. Target light reflected by the datum mirror is imaged on the viewing plane at unit magnification by the collimating lens. If the normal to the datum mirror is parallel to the optical axis of the autocollimator, then the target image is centered on the viewing plane. Any angular deviation of the normal from the optical axis manifests itself as a lateral displacement of the target image from the center. The magnitude of the displacement is proportional to the focal length and to the magnitude (assumed to be small) of the angular deviation. The direction of the displacement is perpendicular to the axis about which the

  19. Absolute airborne gravimetry

    NASA Astrophysics Data System (ADS)

    Baumann, Henri

    This work consists of a feasibility study of a first stage prototype airborne absolute gravimeter system. In contrast to relative systems, which are using spring gravimeters, the measurements acquired by absolute systems are uncorrelated and the instrument is not suffering from problems like instrumental drift, frequency response of the spring and possible variation of the calibration factor. The major problem we had to resolve were to reduce the influence of the non-gravitational accelerations included in the measurements. We studied two different approaches to resolve it: direct mechanical filtering, and post-processing digital compensation. The first part of the work describes in detail the different mechanical passive filters of vibrations, which were studied and tested in the laboratory and later in a small truck in movement. For these tests as well as for the airborne measurements an absolute gravimeter FG5-L from Micro-G Ltd was used together with an Inertial navigation system Litton-200, a vertical accelerometer EpiSensor, and GPS receivers for positioning. These tests showed that only the use of an optical table gives acceptable results. However, it is unable to compensate for the effects of the accelerations of the drag free chamber. The second part describes the strategy of the data processing. It is based on modeling the perturbing accelerations by means of GPS, EpiSensor and INS data. In the third part the airborne experiment is described in detail, from the mounting in the aircraft and data processing to the different problems encountered during the evaluation of the quality and accuracy of the results. In the part of data processing the different steps conducted from the raw apparent gravity data and the trajectories to the estimation of the true gravity are explained. A comparison between the estimated airborne data and those obtained by ground upward continuation at flight altitude allows to state that airborne absolute gravimetry is feasible and

  20. Phylogenomic Dating-A Method of Constraining the Age of Microbial Taxa That Lack a Conventional Fossil Record

    NASA Astrophysics Data System (ADS)

    Blank, Carrine E.

    2009-03-01

    A phylogenomic dating approach was used to identify potential age constraints for multiple archaeal groups, many of which have no fossil, isotopic, or biomarker record. First, well-resolved phylogenetic trees were inferred with the use of multiple gene sequences obtained from whole genome sequences. Next, the ability to use oxygen as a terminal electron acceptor was coded into characters, and ancestral state reconstruction was used to identify clades with taxa that metabolize oxygen and likely had an aerobic ancestor. Next, the habitat of the ancestor was inferred. If the local presence of Cyanobacteria could be excluded from the putative ancestral habitat, then these clades would have originated after the rise in atmospheric oxygen 2.32 Ga. With this method, an upper age of 2.32 Ga (an "oxygen age constraint") is proposed for four major archaeal clades: the Sulfolobales, Thermoplasmatales, Thermoproteus neutrophilus/Pyrobaculum spp., and the Thermoproteales. It was also shown that the halophilic archaea likely had an aerobic common ancestor, yet the possibility of local oxygen oases before oxygenation of the atmosphere could not be formally rejected. Thus, an oxygen age constraint was not assessed for this group. This work suggests that many archaeal groups are not as ancient as many in the research community have previously assumed, and it provides a new method for establishing upper age constraints for major microbial groups that lack a conventional fossil record.

  1. A genetic method for dating ancient genomes provides a direct estimate of human generation interval in the last 45,000 years.

    PubMed

    Moorjani, Priya; Sankararaman, Sriram; Fu, Qiaomei; Przeworski, Molly; Patterson, Nick; Reich, David

    2016-05-17

    The study of human evolution has been revolutionized by inferences from ancient DNA analyses. Key to these studies is the reliable estimation of the age of ancient specimens. High-resolution age estimates can often be obtained using radiocarbon dating, and, while precise and powerful, this method has some biases, making it of interest to directly use genetic data to infer a date for samples that have been sequenced. Here, we report a genetic method that uses the recombination clock. The idea is that an ancient genome has evolved less than the genomes of present-day individuals and thus has experienced fewer recombination events since the common ancestor. To implement this idea, we take advantage of the insight that all non-Africans have a common heritage of Neanderthal gene flow into their ancestors. Thus, we can estimate the date since Neanderthal admixture for present-day and ancient samples simultaneously and use the difference as a direct estimate of the ancient specimen's age. We apply our method to date five Upper Paleolithic Eurasian genomes with radiocarbon dates between 12,000 and 45,000 y ago and show an excellent correlation of the genetic and (14)C dates. By considering the slope of the correlation between the genetic dates, which are in units of generations, and the (14)C dates, which are in units of years, we infer that the mean generation interval in humans over this period has been 26-30 y. Extensions of this methodology that use older shared events may be applicable for dating beyond the radiocarbon frontier.

  2. A genetic method for dating ancient genomes provides a direct estimate of human generation interval in the last 45,000 years

    PubMed Central

    Moorjani, Priya; Sankararaman, Sriram; Fu, Qiaomei; Przeworski, Molly; Patterson, Nick; Reich, David

    2016-01-01

    The study of human evolution has been revolutionized by inferences from ancient DNA analyses. Key to these studies is the reliable estimation of the age of ancient specimens. High-resolution age estimates can often be obtained using radiocarbon dating, and, while precise and powerful, this method has some biases, making it of interest to directly use genetic data to infer a date for samples that have been sequenced. Here, we report a genetic method that uses the recombination clock. The idea is that an ancient genome has evolved less than the genomes of present-day individuals and thus has experienced fewer recombination events since the common ancestor. To implement this idea, we take advantage of the insight that all non-Africans have a common heritage of Neanderthal gene flow into their ancestors. Thus, we can estimate the date since Neanderthal admixture for present-day and ancient samples simultaneously and use the difference as a direct estimate of the ancient specimen’s age. We apply our method to date five Upper Paleolithic Eurasian genomes with radiocarbon dates between 12,000 and 45,000 y ago and show an excellent correlation of the genetic and 14C dates. By considering the slope of the correlation between the genetic dates, which are in units of generations, and the 14C dates, which are in units of years, we infer that the mean generation interval in humans over this period has been 26–30 y. Extensions of this methodology that use older shared events may be applicable for dating beyond the radiocarbon frontier. PMID:27140627

  3. Absolute-structure reports.

    PubMed

    Flack, Howard D

    2013-08-01

    All the 139 noncentrosymmetric crystal structures published in Acta Crystallographica Section C between January 2011 and November 2012 inclusive have been used as the basis of a detailed study of the reporting of absolute structure. These structure determinations cover a wide range of space groups, chemical composition and resonant-scattering contribution. Defining A and D as the average and difference of the intensities of Friedel opposites, their level of fit has been examined using 2AD and selected-D plots. It was found, regardless of the expected resonant-scattering contribution to Friedel opposites, that the Friedel-difference intensities are often dominated by random uncertainty and systematic error. An analysis of data collection strategy is provided. It is found that crystal-structure determinations resulting in a Flack parameter close to 0.5 may not necessarily be from crystals twinned by inversion. Friedifstat is shown to be a robust estimator of the resonant-scattering contribution to Friedel opposites, very little affected by the particular space group of a structure nor by the occupation of special positions. There is considerable confusion in the text of papers presenting achiral noncentrosymmetric crystal structures. Recommendations are provided for the optimal way of treating noncentrosymmetric crystal structures for which the experimenter has no interest in determining the absolute structure.

  4. A New Experimental Method Assessing Attitudes toward Adolescent Dating and Sibling Violence Using Observations of Violent Interactions

    ERIC Educational Resources Information Center

    Reese-Weber, Marla

    2008-01-01

    The present study provides experimental data comparing emerging adults' attitudes toward dating and sibling violence in adolescence using a new methodology in which participants observe a violent interaction between adolescents. The reported amount of violence experienced in dating and sibling relationships among emerging adults is also compared.…

  5. Evolution of terrace risers along the upper Rhine graben inferred from morphologic dating methods: evidence of climatic and tectonic forcing

    NASA Astrophysics Data System (ADS)

    Nivière, B.; Marquis, Guy

    2000-06-01

    We show that morphologic dating techniques that have been applied successfully in arid and semi-arid areas are also suitable for slowly evolving scarps that are usually found in temperate climate environments. We have attempted two morphologic approaches, based on diffusion, to relate the present-day shape of an abandoned terrace riser to its age. The first assumes a model of scarp degradation based on a diffusive process (the D method). The second evaluates the state of scarp degradation using the slope distribution (the SD method) along a topographic profile. By using a manmade scarp of known age, we have obtained a mass diffusivity close to 1.4m2ka-1 when the area experiences a temperate climate characterized by a continuous vegetation cover. However, this value decreases during glacial episodes, probably on account of the permafrost. Even though the SD method requires an age correction that can be easily computed, only this method reveals that at several profiles a later scarp reactivation event has occurred. Indeed, along several profiles, the slope distribution was best fitted by two offset Gaussian curves, suggesting that some scarps have undergone a complex evolution that cannot be modelled with a single diffusive process. This scarp reactivation may correspond to a new incisive episode and allows one to estimate the vertical incision rate along the terrace riser. Applied to a Wurmian terrace riser of the upper Rhine valley (NE France), this approach reveals that the vertical incision rate ranges from 0.2 to 0.85mmyr-1 between 35 and 15ka and that the terrace bevelling occurred during two episodes related to climatic forcing. Moreover, we can identify a component of tectonic forcing evidenced by an increase to the north of vertical incision rate and Rhine stream-power. Another major result is showing that this terrace riser is not isochronous along its strike and that younger portions result from lateral incision of a 30ka pre-existing scarp.

  6. Reconnaissance dating: a new radiocarbon method applied to assessing the temporal distribution of Southern Ocean deep-sea corals

    USGS Publications Warehouse

    Burke, Andrea; Robinson, Laura F.; McNichol, Ann P.; Jenkins, William J.; Scanlon, Kathryn M.; Gerlach, Dana S.

    2010-01-01

    We have developed a rapid 'reconnaissance' method of preparing graphite for 14C/12C analysis. Carbonate (~15 mg) is combusted using an elemental analyzer and the resulting CO2 is converted to graphite using a sealed tube zinc reduction method. Over 85% (n=45 replicates on twenty-one individual corals) of reconnaissance ages measured on corals ranging in age from 500 to 33,000 radiocarbon years (Ryr) are within two standard deviations of ages generated using standard hydrolysis methods on the same corals, and all reconnaissance ages are within 300 Ryr of the standard hydrolysis ages. Replicate measurements on three individual aragonitic corals yielded ages of 1076±35 Ryr (standard deviation; n=5), 10,739±47 Ryr (n=8), and 40,146±3500 Ryr (n=9). No systematic biases were found using different cleaning methods or variable sample sizes. Analysis of 13C/12C was made concurrently with the 14C/12C measurement to correct for natural fractionation and for fractionation during sample processing and analysis. This technique provides a new, rapid method for making accurate, percent-level 14C/12C analyses that may be used to establish the rates and chronology of earth system processes where survey-type modes of age estimation are desirable. For example, applications may include creation of sediment core-top maps, preliminary age models for sediment cores, and growth rate studies of marine organisms such as corals or mollusks. We applied the reconnaissance method to more than 100 solitary deep-sea corals collected in the Drake Passage in the Southern Ocean to investigate their temporal and spatial distribution. The corals used in this study are part of a larger sample set, and the subset that was dated was chosen based on species as opposed to preservation state, so as to exclude obvious temporal biases. Similar to studies in other regions, the distribution of deep-sea corals is not constant through time across the Drake Passage. Most of the corals from the Burdwood Bank

  7. Reconnaissance dating: A new radiocarbon method applied to assessing the temporal distribution of Southern Ocean deep-sea corals

    NASA Astrophysics Data System (ADS)

    Burke, Andrea; Robinson, Laura F.; McNichol, Ann P.; Jenkins, William J.; Scanlon, Kathryn M.; Gerlach, Dana S.

    2010-11-01

    We have developed a rapid 'reconnaissance' method of preparing graphite for 14C/ 12C analysis. Carbonate (˜15 mg) is combusted using an elemental analyzer and the resulting CO 2 is converted to graphite using a sealed tube zinc reduction method. Over 85% ( n=45 replicates on twenty-one individual corals) of reconnaissance ages measured on corals ranging in age from 500 to 33,000 radiocarbon years (Ryr) are within two standard deviations of ages generated using standard hydrolysis methods on the same corals, and all reconnaissance ages are within 300 Ryr of the standard hydrolysis ages. Replicate measurements on three individual aragonitic corals yielded ages of 1076±35 Ryr (standard deviation; n=5), 10,739±47 Ryr ( n=8), and 40,146±3500 Ryr ( n=9). No systematic biases were found using different cleaning methods or variable sample sizes. Analysis of 13C/ 12C was made concurrently with the 14C/ 12C measurement to correct for natural fractionation and for fractionation during sample processing and analysis. This technique provides a new, rapid method for making accurate, percent-level 14C/ 12C analyses that may be used to establish the rates and chronology of earth system processes where survey-type modes of age estimation are desirable. For example, applications may include creation of sediment core-top maps, preliminary age models for sediment cores, and growth rate studies of marine organisms such as corals or mollusks. We applied the reconnaissance method to more than 100 solitary deep-sea corals collected in the Drake Passage in the Southern Ocean to investigate their temporal and spatial distribution. The corals used in this study are part of a larger sample set, and the subset that was dated was chosen based on species as opposed to preservation state, so as to exclude obvious temporal biases. Similar to studies in other regions, the distribution of deep-sea corals is not constant through time across the Drake Passage. Most of the corals from the Burdwood

  8. In situ dating on Mars: A new approach to the K-Ar method utilizing cosmogenic argon

    NASA Astrophysics Data System (ADS)

    Cassata, William S.

    2014-01-01

    Cosmogenic argon isotopes are produced in feldspars via nuclear reactions between cosmic rays and Ca and K atoms within the lattice. These cosmogenic isotopes can be used as proxies for K and Ca, much like nuclear reactor-derived 39Ar and 37Ar are used as proxies for K and Ca, respectively, in 40Ar/39Ar geochronology. If Ca and K are uniformly distributed, then the ratio of radiogenic 40Ar (40Ar*) to cosmogenic 38Ar or 36Ar (38Arcos or 36Arcos) is proportional to the difference between the radioisotopic and exposure ages, as well as the K/Ca ratio of the degassing phase. Thus cosmogenic, radiogenic, and trapped Ar isotopes, all of which can be measured remotely and are stable over geologic time, are sufficient to generate an isochron-like diagram from which the isotopic composition of the trapped component may be inferred. Such data also provide a means to assess the extent to which the system has remained closed with respect to 40Ar*, thereby mitigating otherwise unquantifiable uncertainties that complicate the conventional K-Ar dating method.

  9. Absolute Equilibrium Entropy

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    1997-01-01

    The entropy associated with absolute equilibrium ensemble theories of ideal, homogeneous, fluid and magneto-fluid turbulence is discussed and the three-dimensional fluid case is examined in detail. A sigma-function is defined, whose minimum value with respect to global parameters is the entropy. A comparison is made between the use of global functions sigma and phase functions H (associated with the development of various H-theorems of ideal turbulence). It is shown that the two approaches are complimentary though conceptually different: H-theorems show that an isolated system tends to equilibrium while sigma-functions allow the demonstration that entropy never decreases when two previously isolated systems are combined. This provides a more complete picture of entropy in the statistical mechanics of ideal fluids.

  10. In vivo visualization method by absolute blood flow velocity based on speckle and fringe pattern using two-beam multipoint laser Doppler velocimetry

    NASA Astrophysics Data System (ADS)

    Kyoden, Tomoaki; Naruki, Shoji; Akiguchi, Shunsuke; Ishida, Hiroki; Andoh, Tsugunobu; Takada, Yogo; Momose, Noboru; Homae, Tomotaka; Hachiga, Tadashi

    2016-08-01

    Two-beam multipoint laser Doppler velocimetry (two-beam MLDV) is a non-invasive imaging technique able to provide an image of two-dimensional blood flow and has potential for observing cancer as previously demonstrated in a mouse model. In two-beam MLDV, the blood flow velocity can be estimated from red blood cells passing through a fringe pattern generated in the skin. The fringe pattern is created at the intersection of two beams in conventional LDV and two-beam MLDV. Being able to choose the depth position is an advantage of two-beam MLDV, and the position of a blood vessel can be identified in a three-dimensional space using this technique. Initially, we observed the fringe pattern in the skin, and the undeveloped or developed speckle pattern generated in a deeper position of the skin. The validity of the absolute velocity value detected by two-beam MLDV was verified while changing the number of layers of skin around a transparent flow channel. The absolute velocity value independent of direction was detected using the developed speckle pattern, which is created by the skin construct and two beams in the flow channel. Finally, we showed the relationship between the signal intensity and the fringe pattern, undeveloped speckle, or developed speckle pattern based on the skin depth. The Doppler signals were not detected at deeper positions in the skin, which qualitatively indicates the depth limit for two-beam MLDV.

  11. Absolute multilateration between spheres

    NASA Astrophysics Data System (ADS)

    Muelaner, Jody; Wadsworth, William; Azini, Maria; Mullineux, Glen; Hughes, Ben; Reichold, Armin

    2017-04-01

    Environmental effects typically limit the accuracy of large scale coordinate measurements in applications such as aircraft production and particle accelerator alignment. This paper presents an initial design for a novel measurement technique with analysis and simulation showing that that it could overcome the environmental limitations to provide a step change in large scale coordinate measurement accuracy. Referred to as absolute multilateration between spheres (AMS), it involves using absolute distance interferometry to directly measure the distances between pairs of plain steel spheres. A large portion of each sphere remains accessible as a reference datum, while the laser path can be shielded from environmental disturbances. As a single scale bar this can provide accurate scale information to be used for instrument verification or network measurement scaling. Since spheres can be simultaneously measured from multiple directions, it also allows highly accurate multilateration-based coordinate measurements to act as a large scale datum structure for localized measurements, or to be integrated within assembly tooling, coordinate measurement machines or robotic machinery. Analysis and simulation show that AMS can be self-aligned to achieve a theoretical combined standard uncertainty for the independent uncertainties of an individual 1 m scale bar of approximately 0.49 µm. It is also shown that combined with a 1 µm m‑1 standard uncertainty in the central reference system this could result in coordinate standard uncertainty magnitudes of 42 µm over a slender 1 m by 20 m network. This would be a sufficient step change in accuracy to enable next generation aerospace structures with natural laminar flow and part-to-part interchangeability.

  12. Radiometric Dating in Geology.

    ERIC Educational Resources Information Center

    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)

  13. Absolute distance measurement method without a non-measurable range and directional ambiguity based on the spectral-domain interferometer using the optical comb of the femtosecond pulse laser

    NASA Astrophysics Data System (ADS)

    Park, J.; Jin, J.; Kim, J.-A.; Kim, J. W.

    2016-12-01

    With the help of the optical comb of a femtosecond pulse laser, a spectral-domain interferometer has been utilized for measuring absolute distances. Even if the technique can measure distances at a high speed and with good precision, it has two fundamental problems: non-measurable range and directional ambiguity. First, the non-measurable range arises due to the sampling limit of the interference spectra at very short distances or the integer multiple of a double non-ambiguity range. Second, the peak corresponding to the desired distance in the Fourier domain has a directional ambiguity owing to the repeated property of the optical comb. Therefore, due to these two fundamental problems, most previous works never measure the absolute distances by itself in a single operation. In this letter, an interferometric method for measuring arbitrary absolute distances based on a spectral-domain interferometer operating with two reference mirrors is proposed and demonstrated. The two reference mirrors generate two distinguishable signals, primary and secondary, with a predetermined offset, thus solving these fundamental problems clearly. More importantly, as a practical advantage, the simple layout of the proposed method makes it readily applicable to most previous studies.

  14. Bayesian methods applied to the interpretation of multiple OSL dates: high precision sediment ages from Old Scatness Broch excavations, Shetland Isles

    NASA Astrophysics Data System (ADS)

    Rhodes, E. J.; Bronk Ramsey, C.; Outram, Z.; Batt, C.; Willis, L.; Dockrill, S.; Bond, J.

    2003-05-01

    In this paper, we illustrate the ways in which Bayesian statistical techniques may be used to enhance chronological resolution when applied to a series of OSL sediment dates. Such application can achieve an optimal chronological model by incorporating stratigraphic and age information. The application to luminescence data is not straightforward owing to the sources of uncertainty in each date, and here we present one solution to overcoming these difficulties, and introduce the concept of "unshared systematic" errors. Using OSL sediment dates from the site of Old Scatness Broch, Shetland Isles, UK, many measured with a high degree of precision, we illustrate some of the ways in which Bayesian techniques may be applied, as a tool for assessing systematic errors when combined with independent chronological information, and to determine the optimum chronological information for specific events and contexts. We provide a detailed procedure for the application of Bayesian methods to OSL dates using the widely available radiocarbon calibration programme OxCal.

  15. Evaluating methods used for fission track dating of tephras: examples from the Afar Depression, Ethiopia, and the Denali fault zone, Alaska

    NASA Astrophysics Data System (ADS)

    Blythe, A. E.; Warfel, T. S.; Phillips, D. J.

    2015-12-01

    Although fission track geochronology has been successfully used to date volcanic glasses and tephras in several studies, a variety of approaches have been used (see Westgate et al., 2013), and no consensus for a standardized methodology has emerged. As a result, this technique is rarely employed, despite having the potential to date tephras and glasses that cannot be dated by other methods, such as K-Ar dating. We have been evaluating the various approaches used to address the technical issues in fission track dating of tephras, by applying them to standards of known ages, including Moldavite tektite, and Huckleberry and Bishop Tuffs. Some of these issues include track etching and counting protocol, and corrections for the effects of track fading at low temperatures. Track etching is generally done in 24% HF for 75 or more seconds, but the time necessary for optimal etching appears to vary according to sample composition and grain size. To correct for track fading, we are using the diameter correction technique of Sandhu and Westgate (1995). We have obtained tephra samples from two regions, the Afar Depression in Ethiopia, an area with significant early hominid fossils, and the Denali fault zone in Alaska, an area with a complicated tectonic evolution. For both of these regions, we have samples that have been dated by other methods for calibration purposes, and we will explore the application of a Zeta correction to the technique. This underutilized technique can provide powerful constraints on studies of timing in diverse geologic environments.

  16. Bias Properties of Extragalactic Distance Indicators. XI. Methods to Correct for Observational Selection Bias for RR Lyrae Absolute Magnitudes from Trigonometric Parallaxes Expected from the Full-Sky Astrometric Mapping Explorer Satellite

    NASA Astrophysics Data System (ADS)

    Sandage, Allan; Saha, A.

    2002-04-01

    A short history is given of the development of the correction for observation selection bias inherent in the calibration of absolute magnitudes using trigonometric parallaxes. The developments have been due to Eddington, Jeffreys, Trumpler & Weaver, Wallerstein, Ljunggren & Oja, West, Lutz & Kelker, after whom the bias is named, Turon Lacarrieu & Crézé, Hanson, Smith, and many others. As a tutorial to gain an intuitive understanding of several complicated trigonometric bias problems, we study a toy bias model of a parallax catalog that incorporates assumed parallax measuring errors of various severities. The two effects of bias errors on the derived absolute magnitudes are (1) the Lutz-Kelker correction itself, which depends on the relative parallax error δπ/π and the spatial distribution, and (2) a Malmquist-like ``incompleteness'' correction of opposite sign due to various apparent magnitude cutoffs as they are progressively imposed on the catalog. We calculate the bias properties using simulations involving 3×106 stars of fixed absolute magnitude using Mv=+0.6 to imitate RR Lyrae variables in the mean. These stars are spread over a spherical volume bounded by a radius 50,000 pc with different spatial density distributions. The bias is demonstrated by first using a fixed rms parallax uncertainty per star of 50 μas and then using a variable rms accuracy that ranges from 50 μas at apparent magnitude V=9 to 500 μas at V=15 according to the specifications for the Full-Sky Astrometric Mapping Explorer (FAME) satellite to be launched in 2004. The effects of imposing magnitude limits and limits on the ``observer's'' error, δπ/π, are displayed. We contrast the method of calculating mean absolute magnitude directly from the parallaxes where bias corrections are mandatory, with an inverse method using maximum likelihood that is free of the Lutz-Kelker bias, although a Malmquist bias is present. Simulations show the power of the inverse method. Nevertheless, we

  17. Quantitative standards for absolute linguistic universals.

    PubMed

    Piantadosi, Steven T; Gibson, Edward

    2014-01-01

    Absolute linguistic universals are often justified by cross-linguistic analysis: If all observed languages exhibit a property, the property is taken to be a likely universal, perhaps specified in the cognitive or linguistic systems of language learners and users. In many cases, these patterns are then taken to motivate linguistic theory. Here, we show that cross-linguistic analysis will very rarely be able to statistically justify absolute, inviolable patterns in language. We formalize two statistical methods--frequentist and Bayesian--and show that in both it is possible to find strict linguistic universals, but that the numbers of independent languages necessary to do so is generally unachievable. This suggests that methods other than typological statistics are necessary to establish absolute properties of human language, and thus that many of the purported universals in linguistics have not received sufficient empirical justification.

  18. Universal Cosmic Absolute and Modern Science

    NASA Astrophysics Data System (ADS)

    Kostro, Ludwik

    The official Sciences, especially all natural sciences, respect in their researches the principle of methodic naturalism i.e. they consider all phenomena as entirely natural and therefore in their scientific explanations they do never adduce or cite supernatural entities and forces. The purpose of this paper is to show that Modern Science has its own self-existent, self-acting, and self-sufficient Natural All-in Being or Omni-Being i.e. the entire Nature as a Whole that justifies the scientific methodic naturalism. Since this Natural All-in Being is one and only It should be considered as the own scientifically justified Natural Absolute of Science and should be called, in my opinion, the Universal Cosmic Absolute of Modern Science. It will be also shown that the Universal Cosmic Absolute is ontologically enormously stratified and is in its ultimate i.e. in its most fundamental stratum trans-reistic and trans-personal. It means that in its basic stratum. It is neither a Thing or a Person although It contains in Itself all things and persons with all other sentient and conscious individuals as well, On the turn of the 20th century the Science has begun to look for a theory of everything, for a final theory, for a master theory. In my opinion the natural Universal Cosmic Absolute will constitute in such a theory the radical all penetrating Ultimate Basic Reality and will substitute step by step the traditional supernatural personal Absolute.

  19. Estimating Absolute Site Effects

    SciTech Connect

    Malagnini, L; Mayeda, K M; Akinci, A; Bragato, P L

    2004-07-15

    The authors use previously determined direct-wave attenuation functions as well as stable, coda-derived source excitation spectra to isolate the absolute S-wave site effect for the horizontal and vertical components of weak ground motion. They used selected stations in the seismic network of the eastern Alps, and find the following: (1) all ''hard rock'' sites exhibited deamplification phenomena due to absorption at frequencies ranging between 0.5 and 12 Hz (the available bandwidth), on both the horizontal and vertical components; (2) ''hard rock'' site transfer functions showed large variability at high-frequency; (3) vertical-motion site transfer functions show strong frequency-dependence, and (4) H/V spectral ratios do not reproduce the characteristics of the true horizontal site transfer functions; (5) traditional, relative site terms obtained by using reference ''rock sites'' can be misleading in inferring the behaviors of true site transfer functions, since most rock sites have non-flat responses due to shallow heterogeneities resulting from varying degrees of weathering. They also use their stable source spectra to estimate total radiated seismic energy and compare against previous results. they find that the earthquakes in this region exhibit non-constant dynamic stress drop scaling which gives further support for a fundamental difference in rupture dynamics between small and large earthquakes. To correct the vertical and horizontal S-wave spectra for attenuation, they used detailed regional attenuation functions derived by Malagnini et al. (2002) who determined frequency-dependent geometrical spreading and Q for the region. These corrections account for the gross path effects (i.e., all distance-dependent effects), although the source and site effects are still present in the distance-corrected spectra. The main goal of this study is to isolate the absolute site effect (as a function of frequency) by removing the source spectrum (moment-rate spectrum) from

  20. Landsat-5 TM reflective-band absolute radiometric calibration

    USGS Publications Warehouse

    Chander, G.; Helder, D.L.; Markham, B.L.; Dewald, J.D.; Kaita, E.; Thome, K.J.; Micijevic, E.; Ruggles, T.A.

    2004-01-01

    The Landsat-5 Thematic Mapper (TM) sensor provides the longest running continuous dataset of moderate spatial resolution remote sensing imagery, dating back to its launch in March 1984. Historically, the radiometric calibration procedure for this imagery used the instrument's response to the Internal Calibrator (IC) on a scene-by-scene basis to determine the gain and offset of each detector. Due to observed degradations in the IC, a new procedure was implemented for U.S.-processed data in May 2003. This new calibration procedure is based on a lifetime radiometric calibration model for the instrument's reflective bands (1-5 and 7) and is derived, in part, from the IC response without the related degradation effects and is tied to the cross calibration with the Landsat-7 Enhanced Thematic Mapper Plus. Reflective-band absolute radiometric accuracy of the instrument tends to be on the order of 7% to 10%, based on a variety of calibration methods.

  1. Development of absolute quantification method for genotype-specific Babesia microti using real-time PCR and practical experimental tips of real-time PCR.

    PubMed

    Ohmori, Shiho; Nagano-Fujii, Motoko; Saito-Ito, Atsuko

    2016-10-01

    Babesia microti, a rodent babesia, is known as a pathogen of zoonosis, human babesiosis, is composed of several genotypes of small subunit ribosomal RNA gene (SSUrDNA) and different genotypes have been suggested to have different infectivity and pathogenicity to humans. We established a real-time PCR assay using SYBR Green I, which allows specific detection and absolute quantification for each SSUrDNA-type-B. microti of four SSUrDNA-types found in Japanese rodents even in mixed infection. In this assay, four genotype-specific primer pairs targeted on internal transcribed spacer 1 or 2 sequences were used. Primer pairs have the characteristics for a high specificity for homologous genotype DNA. The calibration curves of cycle threshold (Ct) values versus log concentrations of DNA for all four genotypes were linear over 10(7) fold range of DNA concentrations with correlation coefficient from 0.95 to 1 and sufficient amplification efficiency from 90% to 110%. The standard curves for all four genotypes were not changed even in the presence of heterologous DNA. In this paper, we introduce how to establish and perform the genotype-specific real-time PCR and our practical experimental tips to be recommended.

  2. Radiocarbon dating of glacier ice: overview, optimisation, validation and potential

    NASA Astrophysics Data System (ADS)

    Uglietti, Chiara; Zapf, Alexander; Jenk, Theo Manuel; Sigl, Michael; Szidat, Sönke; Salazar, Gary; Schwikowski, Margit

    2016-12-01

    High-altitude glaciers and ice caps from midlatitudes and tropical regions contain valuable signals of past climatic and environmental conditions as well as human activities, but for a meaningful interpretation this information needs to be placed in a precise chronological context. For dating the upper part of ice cores from such sites, several relatively precise methods exist, but they fail in the older and deeper parts, where plastic deformation of the ice results in strong annual layer thinning and a non-linear age-depth relationship. If sufficient organic matter such as plant, wood or insect fragments were found, radiocarbon (14C) analysis would have thus been the only option for a direct and absolute dating of deeper ice core sections. However such fragments are rarely found and, even then, they would not be very likely to occur at the desired depth and resolution. About 10 years ago, a new, complementary dating tool was therefore introduced by our group. It is based on extracting the µg-amounts of the water-insoluble organic carbon (WIOC) fraction of carbonaceous aerosols embedded in the ice matrix for subsequent 14C dating. Since then this new approach has been improved considerably by reducing the measurement time and improving the overall precision. Samples with ˜ 10 µg WIOC mass can now be dated with reasonable uncertainty of around 10-20 % (variable depending on sample age). This requires about 300 to 800 g of ice for WIOC concentrations typically found in midlatitude and low-latitude glacier ice. Dating polar ice with satisfactory age precision is still not possible since WIOC concentrations are around 1 order of magnitude lower. The accuracy of the WIOC 14C method was validated by applying it to independently dated ice. With this method, the deepest parts of the ice cores from Colle Gnifetti and the Mt Ortles glacier in the European Alps, Illimani glacier in the Bolivian Andes, Tsambagarav ice cap in the Mongolian Altai, and Belukha glacier

  3. Absolute quantification of the alleles in somatic point mutations by bioluminometric methods based on competitive polymerase chain reaction in the presence of a locked nucleic acid blocker or an allele-specific primer.

    PubMed

    Iliadi, Alexandra; Petropoulou, Margarita; Ioannou, Penelope C; Christopoulos, Theodore K; Anagnostopoulos, Nikolaos I; Kanavakis, Emmanuel; Traeger-Synodinos, Jan

    2011-09-01

    In somatic (acquired) point mutations, the challenge is to quantify minute amounts of the mutant allele in the presence of a large excess of the normal allele that differs only in a single base pair. We report two bioluminometric methods that enable absolute quantification of the alleles. The first method exploits the ability of a locked nucleic acid (LNA) oligonucleotide to bind to and inhibit effectively the polymerase chain reaction (PCR) amplification of the normal allele while the amplification of the mutant allele remains unaffected. The second method employs allele-specific PCR primers, thereby allowing the amplification of the corresponding allele only. DNA internal standards (competitors) are added to the PCR mixture to compensate for any sample-to-sample variation in the amplification efficiency. The amplification products from the two alleles and the internal standards are quantified by a microtiter well-based bioluminometric hybridization assay using the photoprotein aequorin as a reporter. The methods allow absolute quantification of less than 300 copies of the mutant allele even in samples containing less than 1% of the mutant allele.

  4. Single-grain optical dating properties of JSC Mars-1: preliminary measurements of radiation dose response and sensitivity change.

    SciTech Connect

    Lepper, K. E.

    2003-01-01

    Martian surface deposits, including polar deposits, represent a vast storehouse of data recording the evolution Of Mars' climate and surface environment. However, the greatest challenge to deciphering these martian geo-records is the need for absolute dating techniques, Particularly those techniques applicable to the timeframes and surface processes of the 'Martian Quaternary'. Lepper and McKeever [3,4] have proposed developing optical dating, an established terrestrial chronometric dating method based on principles eri'solid-state physics, for retnote in-situ dating oCrnartian surface seditnents.

  5. Dating Techniques in Archaeology and Paleoanthropology.

    ERIC Educational Resources Information Center

    Taylor, R. E.

    1987-01-01

    Discusses some of the new physical dating methods being used by archaeologists and paleoanthropologists to study the material remains of ancient primates. Describes the quaternary physical dating techniques, advances in radiocarbon dating, and the radiocalcium data method. (TW)

  6. U-Pb dating of Plinian-eruption ashfalls by the isotope dilution method: A reliable and precise tool for time-scale calibration and biostratigraphic correlation

    SciTech Connect

    Tucker, R.D. . Dept. of Earth and Planetary Sciences)

    1992-01-01

    Through a combination of low analytical blanks, clean Pb-205 enriched tracer-solution, and refined procedures of sample preparation, it is possible to isolate and measure minute quantities of radiogenic Pb in concordant zircon, thereby permitting accurate isotopic age determinations of small multigrain samples of Paleozoic zircon with 7--20 ppm radiogenic Pb. Refinement of these procedures, including reduction of laboratory blank, allows for analysis of single grains of Paleozoic zircon with greater than 25 ppm radiogenic Pb with an age precision of better than 1%. Mass spectrometric measurement of all Pb and U isotopes allows for the calculation of three isotopic ages from a single sample. Concordant multigrain and single-grain U-Pb zircon analyses from 13 biostratigraphically dated K-bentonites in Europe and North America define an internally consistent, absolute chronostratigraphy of Middle ordovician to Upper silurian stratotypes. As a test of trans-Atlantic stratigraphic correlation, a volcanic ash from Middle Ordovician (Rocklandian) strata of North America was found to be in excellent age agreement with Caradocian K-bentonites in Britain and Sweden, demonstrating age equivalence of sedimentary sequences lacking directly comparable fauna. In other case, precise dating of single zircons from three Caradocian K-bentonite in Sweden and Virginia was performed to test a hypothesis that a single ultraplinian volcanic eruption deposited airborne debris on both Larentia and Baltica. The ages of these presumed correlative ashes will be shown to provide quantitative information about the depositional rates of their enclosing strata, as well as tectonic events affecting the margins of Iapetus in Ordovician time.

  7. Absolute nuclear material assay using count distribution (LAMBDA) space

    DOEpatents

    Prasad, Mano K.; Snyderman, Neal J.; Rowland, Mark S.

    2015-12-01

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  8. Absolute nuclear material assay using count distribution (LAMBDA) space

    DOEpatents

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2012-06-05

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  9. Urey: to measure the absolute age of Mars

    NASA Technical Reports Server (NTRS)

    Randolph, J. E.; Plescia, J.; Bar-Cohen, Y.; Bartlett, P.; Bickler, D.; Carlson, R.; Carr, G.; Fong, M.; Gronroos, H.; Guske, P. J.; Herring, M.; Javadi, H.; Johnson, D. W.; Larson, T.; Malaviarachchi, K.; Sherrit, S.; Stride, S.; Trebi-Ollennu, A.; Warwick, R.

    2003-01-01

    UREY, a proposed NASA Mars Scout mission will, for the first time, measure the absolute age of an identified igneous rock formation on Mars. By extension to relatively older and younger rock formations dated by remote sensing, these results will enable a new and better understanding of Martian geologic history.

  10. Onset of industrial pollution recorded in Mumbai mudflat sediments, using integrated magnetic, chemical, 210Pb dating, and microscopic methods.

    PubMed

    Blaha, U; Basavaiah, N; Deenadayalan, K; Borole, D V; Mohite, R D

    2011-01-15

    The onset and rise of urban and industrial pollution in the Mumbai region was reconstructed from an anthropogenically contaminated mudflat sediment profile from the adjacent Thane creek using magnetic parameters, polycyclic aromatic hydrocarbon (PAH) data, metal contents, and the (210)Pb dating technique. The 1.8 m vertical section at Airoli (Navi Mumbai) reveals an increase of magnetic susceptibility (χ) from background values of (20-50) to (75-100) × 10(-8) [m(3) kg(-1)] in the anthropogenically affected zone above ∼93 cm. A sharp rise of χ from (75-100) to (130-215) × 10(-8) [m(3) kg(-1)] subdivides the anthropogenically affected zone at a depth of ∼63 cm. Characterization with rock magnetic parameters (SIRM, Soft IRM, and S-ratio) reveals a significant contribution of ferri(o)magnetic phases in the upper zone. Based on the magnetic classification sampling intervals for cost-intensive PAH and metal analyses were determined. Steadily increasing contents of PAH and metals of anthropogenic origin are observed above the boundary depth at ∼93 cm. A sediment accumulation rate of 1.2 ± 0.3 cm/yr provided by (210)Pb dating dates the ∼63 cm boundary to 1951. Increasing industrial activity, including the establishment of a coal-fired power plant in 1956, and refineries between 1955 and 1960, correlates well with the substantial increase of χ, PAH, and metal contents. Scanning electron microscopy (SEM) investigation on magnetic extracts from the contaminated zone reveals the presence of magnetic spherules derived from industrial high-temperature processes.

  11. Dating the Martian meteorite Zagami by the 87Rb-87Sr isochron method with a prototype in situ resonance ionization mass spectrometer

    PubMed Central

    Scott Anderson, F; Levine, Jonathan; Whitaker, Tom J

    2015-01-01

    RATIONALE The geologic history of the Solar System builds on an extensive record of impact flux models, crater counts, and ∼270 kg of lunar samples analyzed in terrestrial laboratories. However, estimates of impactor flux may be biased by the fact that most of the dated Apollo samples were only tenuously connected to an assumed geologic context. Moreover, uncertainties in the modeled cratering rates are significant enough to lead to estimated errors for dates on Mars and the Moon of ∼1 Ga. Given the great cost of sample return missions, combined with the need to sample multiple terrains on multiple planets, we have developed a prototype instrument that can be used for in situ dating to better constrain the age of planetary samples. METHODS We demonstrate the first use of laser ablation resonance ionization mass spectrometry for 87Rb-87Sr isochron dating of geological specimens. The demands of accuracy and precision have required us to meet challenges including regulation of the ambient temperature, measurement of appropriate backgrounds, sufficient ablation laser intensity, avoidance of the defocusing effect of the plasma created by ablation pulses, and shielding of our detector from atoms and ions of other elements. RESULTS To test whether we could meaningfully date planetary materials, we have analyzed a piece of the Martian meteorite Zagami. In each of four separate measurements we obtained 87Rb-87Sr isochron ages for Zagami consistent with its published age, and, in both of two measurements that reached completion, we obtained better than 200 Ma precision. Combining all our data into a single isochron with 581 spot analyses gives an 87Rb-87Sr age for this specimen of 360 ±90 Ma. CONCLUSIONS Our analyses of the Zagami meteorite represent the first successful application of resonance ionization mass spectrometry to isochron geochronology. Furthermore, the technique is miniaturizable for spaceflight and in situ dating on other planetary bodies. © 2014 The

  12. Cryogenic, Absolute, High Pressure Sensor

    NASA Technical Reports Server (NTRS)

    Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

    2001-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  13. The performance of different propensity-score methods for estimating differences in proportions (risk differences or absolute risk reductions) in observational studies.

    PubMed

    Austin, Peter C

    2010-09-10

    Propensity score methods are increasingly being used to estimate the effects of treatments on health outcomes using observational data. There are four methods for using the propensity score to estimate treatment effects: covariate adjustment using the propensity score, stratification on the propensity score, propensity-score matching, and inverse probability of treatment weighting (IPTW) using the propensity score. When outcomes are binary, the effect of treatment on the outcome can be described using odds ratios, relative risks, risk differences, or the number needed to treat. Several clinical commentators suggested that risk differences and numbers needed to treat are more meaningful for clinical decision making than are odds ratios or relative risks. However, there is a paucity of information about the relative performance of the different propensity-score methods for estimating risk differences. We conducted a series of Monte Carlo simulations to examine this issue. We examined bias, variance estimation, coverage of confidence intervals, mean-squared error (MSE), and type I error rates. A doubly robust version of IPTW had superior performance compared with the other propensity-score methods. It resulted in unbiased estimation of risk differences, treatment effects with the lowest standard errors, confidence intervals with the correct coverage rates, and correct type I error rates. Stratification, matching on the propensity score, and covariate adjustment using the propensity score resulted in minor to modest bias in estimating risk differences. Estimators based on IPTW had lower MSE compared with other propensity-score methods. Differences between IPTW and propensity-score matching may reflect that these two methods estimate the average treatment effect and the average treatment effect for the treated, respectively.

  14. Absolute cavity pyrgeometer

    DOEpatents

    Reda, Ibrahim

    2013-10-29

    Implementations of the present disclosure involve an apparatus and method to measure the long-wave irradiance of the atmosphere or long-wave source. The apparatus may involve a thermopile, a concentrator and temperature controller. The incoming long-wave irradiance may be reflected from the concentrator to a thermopile receiver located at the bottom of the concentrator to receive the reflected long-wave irradiance. In addition, the thermopile may be thermally connected to a temperature controller to control the device temperature. Through use of the apparatus, the long-wave irradiance of the atmosphere may be calculated from several measurements provided by the apparatus. In addition, the apparatus may provide an international standard of pyrgeometers' calibration that is traceable back to the International System of Units (SI) rather than to a blackbody atmospheric simulator.

  15. Development and validation of a liquid chromatography/electrospray ionization time-of-flight mass spectrometry method for relative and absolute quantification of steroidal alkaloids in Fritillaria species.

    PubMed

    Zhou, Jian-Liang; Li, Ping; Li, Hui-Jun; Jiang, Yan; Ren, Mei-Ting; Liu, Ying

    2008-01-04

    Steroidal alkaloids are naturally occurring nitrogen-containing compounds in many edible or medicinal plants, such as potato, tomato, Fritillaria and American hellebore, which possess a variety of toxicological and pharmacological effects on humans. The aim of this study is to explore the potential of liquid chromatography/electrospray ionization time-of-flight mass spectrometry (LC/ESI-TOF-MS) method in the determination of these important alkaloids in plant matrices. The application of this method has been proven through 26 naturally occurring steroidal alkaloids in Fritillaria species. Accurate mass measurements within 4 ppm error were obtained for all the alkaloids detected out of various plant matrices, which allowed an unequivocal identification of the target steroidal alkaloids. The bunching factor for mass spectrometer, an important parameter significantly affecting the precision and accuracy of quantitative method, was firstly optimized in this work and satisfactory precision and linearity were achieved by the optimization of that parameter. The ranges of RSD values of intra-day and inter-day variability for all alkaloids were decreased remarkably from 41.8-159% and 13.2-140% to 0.32-7.98% and 2.37-16.1%, respectively, when the value of bunching factor was optimized from 1 to 3. Linearity of response more than two orders of magnitude was also demonstrated (regression coefficient >0.99). The LC/TOF-MS detection method offered improvements to the sensitivity, compared with previously applied LC (or GC) methods, with limits of detection down to 0.0014-0.0335 microg/ml. The results in this paper illustrate the robustness and applicability of LC/TOF-MS for steroidal alkaloids analysis in plant samples. In addition, relative quantitative determination of steroidal alkaloid with one popular analyte verticinone which is commercially available was also investigated in order to break through the choke point of lack of standards in phytochemical analysis. The

  16. A 20-ka reconstruction of a Sahelo-Sudanian paleoenvironment using multi-method dating on pedogenic carbonate

    NASA Astrophysics Data System (ADS)

    Diaz, Nathalie; Dietrich, Fabienne; King, Georgina E.; Valla, Pierre G.; Sebag, David; Herman, Frédéric; Verrecchia, Eric P.

    2016-04-01

    Soils can be precious environmental archives as they are open systems resulting from external persistent disturbance, or forcing (Jenny, 1941). Pedogenic carbonate nodules associated with clay-rich soils have been investigated in the Far North region of Cameroon in non-carbonate watersheds (Chad Basin). Nodule bearing soils have mima-like mound morphologies, within stream networks. Such settings raise questions on the processes leading to carbonate precipitation as well as landscape genesis. The mima-like mounds have been identified as degraded Vertisols, resulting from differential erosion induced by a former gilgai micro-relief (Diaz et al., 2016). Non-degraded Vertisols occur in waterlogged areas, located downstream from mima-like mound locations (Braband and Gavaud, 1985). Therefore during a former wetter period Vertisols may have been extended to the mima-like mound areas, followed by a shift toward drier conditions and erosion (Diaz et al., 2016). Consequently, mima-like mounds and associated carbonate nodules are inherited from climatic changes during the Late Pleistocene-Holocene period. The aim of this study is to validate the scenario above using the carbonate nodules collected in a mima-like mound as time archives. Optically stimulated luminescence (OSL) dating of K-feldspars trapped within the nodules is used to assess the deposition time of the soil parent material, composing the mima-like mounds. The carbonate and organic nodule parts have been radiocarbon dated with the aim of assessing the carbonate precipitation age and the age range of soil formation, respectively. Results show that the soil parent material was deposited between 18 ka and 12 ka BP and that the nodules precipitated between 7 ka and 5 ka BP. These results suggest that the deposition occurred during the arid climatic period of the Bossoumian (20 ka to 15 ka BP; Hervieu, 1970) and during the first drier part of the African Humid Period (14.8 ka to 11.5 ka BP; deMenocal et al., 2000

  17. Dating techniques in archaeology and paleoanthropology

    SciTech Connect

    Taylor, R.E.

    1987-02-15

    Archaeologists have an increasing array of physical dating methods at their disposal. R.E. Taylor of the University of California discusses available techniques, recent advances in radiocarbon dating, and current developments in radiocalcium dating.

  18. Age of the North Anatolian Fault Segments in the Yalova with U/Th Dating Method by Travertine Data

    NASA Astrophysics Data System (ADS)

    Selim, Haluk; Ömer Taş, K.

    2016-04-01

    Travertine occurrences developed along the segments of the North Anatolian Fault (NAF) in the south of Yalova. Travertines outcrop approximately 1 km2 area. These are middle-thick bedded approximately 20-40 m and back-tilted southward or horizontally. Lithology of travertines deposited such as physolite, stalactites-stalagmites, cave pearls, sharp pebble carbonate nodules, spherical-roller-intricate shapes or laminated banded travertine. Geochemical analyses were performed on the six samples of the travertines. X-ray analysis indicates that all samples are entirely composed of low-Mg calcite. Banded travertines with some tubular structures formed by precipitation from rising hot water are best developed near the toes of the large, hanging-wall-derived alluvial fans, whereas phreatic cement preferentially exists in footwall-derived, alluvial-fan conglomerates. The unit developed clarity which is controlled by normal fault as the structural and morphological, relationship with active tectonics. The travertines are a range-front type. U/Th series age dating results indicate that the travertine deposition extends back to 155 ka and yields ages of 60.000 (± 3, 091) to 153.149 (±13,466) from the range-front type travertines.

  19. Measurement of Absolute Myocardial Blood Flow in Humans Using Dynamic Cardiac SPECT and 99mTc-tetrofosmin: Method and Validation

    PubMed Central

    Shrestha, Uttam; Sciammarella, Maria; Alhassen, Fares; Yeghiazarians, Yerem; Ellin, Justin; Verdin, Emily; Boyle, Andrew; Seo, Youngho; Botvinick, Elias H.; Gullberg, Grant T.

    2015-01-01

    Background The objective of this study was to measure myocardial blood flow (MBF) in humans using 99mTc-tetrofosmin and dynamic single photon emission computed tomography (SPECT). Methods Dynamic SPECT using 99mTc-tetrofosmin and dynamic positron emission tomography (PET) was performed on a group of 16 patients. The SPECT data were reconstructed using a 4D-spatiotemporal iterative reconstruction method. The data corresponding to 9 patients were used to determine the flow-extraction curve for 99mTc-tefrofosmin while data from the remaining 7 patients were used for method validation. The nonlinear tracer correction parameters A and B for 99mTc-tefrofosmin were estimated for the 9 patients by fitting the flow-extraction curve K1=F(1−Aexp(−BF)) for K1 values estimated with 99mTc-tefrofosmin using SPECT and MBF values estimated with 13N-NH3 using PET. These parameters were then used to calculate MBF and coronary flow reserve (CFR) in three coronary territories (LAD, RCA, and LCX) using SPECT for an independent cohort of 7 patients. The results were then compared with that estimated with 13N-NH3 PET. The flow dependent permeability surface-area product (PS) for 99mTc-tefrofosmin was also estimated. Results The estimated flow extraction parameters for 99mTc-tefrofosmin was found to be A=0.91±0.11, B=0.34±0.20 (R2 = 0.49). The range of MBF in LAD, RCA, and LCX was 0.44 ml/min/g to 3.81 ml/min/g. The MBF between PET and SPECT in the group of independent cohort of 7 patients showed statistically significant correlation, r = 0.71 (p < 0.001). However, the corresponding CFR correlation was moderate r = 0.39 yet statistically significant (p = 0.037). The PS for 99mTc-tefrofosmin was (0.091 ± 0.10) * MBF = (0.32 ± 0.16). Conclusions Dynamic cardiac SPECT using 99mTc-tetrofosmin and a clinical two-headed SPECT/CT scanner can be a useful tool for estimation of MBF. PMID:26715603

  20. Absolute radiometric calibration of advanced remote sensing systems

    NASA Technical Reports Server (NTRS)

    Slater, P. N.

    1982-01-01

    The distinction between the uses of relative and absolute spectroradiometric calibration of remote sensing systems is discussed. The advantages of detector-based absolute calibration are described, and the categories of relative and absolute system calibrations are listed. The limitations and problems associated with three common methods used for the absolute calibration of remote sensing systems are addressed. Two methods are proposed for the in-flight absolute calibration of advanced multispectral linear array systems. One makes use of a sun-illuminated panel in front of the sensor, the radiance of which is monitored by a spectrally flat pyroelectric radiometer. The other uses a large, uniform, high-radiance reference ground surface. The ground and atmospheric measurements required as input to a radiative transfer program to predict the radiance level at the entrance pupil of the orbital sensor are discussed, and the ground instrumentation is described.

  1. Database applicaton for absolute spectrophotometry

    NASA Astrophysics Data System (ADS)

    Bochkov, Valery V.; Shumko, Sergiy

    2002-12-01

    32-bit database application with multidocument interface for Windows has been developed to calculate absolute energy distributions of observed spectra. The original database contains wavelength calibrated observed spectra which had been already passed through apparatus reductions such as flatfielding, background and apparatus noise subtracting. Absolute energy distributions of observed spectra are defined in unique scale by means of registering them simultaneously with artificial intensity standard. Observations of sequence of spectrophotometric standards are used to define absolute energy of the artificial standard. Observations of spectrophotometric standards are used to define optical extinction in selected moments. FFT algorithm implemented in the application allows performing convolution (deconvolution) spectra with user-defined PSF. The object-oriented interface has been created using facilities of C++ libraries. Client/server model with Windows Socket functionality based on TCP/IP protocol is used to develop the application. It supports Dynamic Data Exchange conversation in server mode and uses Microsoft Exchange communication facilities.

  2. Piloting the use of indigenous methods to prevent Nipah virus infection by interrupting bats' access to date palm sap in Bangladesh.

    PubMed

    Nahar, Nazmun; Mondal, Utpal Kumar; Sultana, Rebeca; Hossain, M Jahangir; Khan, M Salah Uddin; Gurley, Emily S; Oliveras, Elizabeth; Luby, Stephen P

    2013-09-01

    People in Bangladesh frequently drink fresh date palm sap. Fruit bats (Pteropus giganteus) also drink raw sap and may contaminate the sap by shedding Nipah virus through saliva and urine. In a previous study we identified two indigenous methods to prevent bats accessing the sap, bamboo skirts and lime (calcium carbonate). We conducted a pilot study to assess the acceptability of these two methods among sap harvesters. We used interactive community meetings and group discussions to encourage all the sap harvesters (n = 12) from a village to use either bamboo skirts or lime smear that some of them (n = 4) prepared and applied. We measured the preparation and application time and calculated the cost of bamboo skirts. We conducted interviews after the use of each method. The sap harvesters found skirts effective in preventing bats from accessing sap. They were sceptical that lime would be effective as the lime was washed away by the sap flow. Preparation of the skirt took ∼105 min. The application of each method took ∼1 min. The cost of the bamboo skirt is minimal because bamboo is widely available and they made the skirts with pieces of used bamboo. The bamboo skirt method appeared practical and affordable to the sap harvesters. Further studies should explore its ability to prevent bats from accessing date palm sap and assess if its use produces more or better quality sap, which would provide further incentives to make it more acceptable for its regular use.

  3. Absolute classification with unsupervised clustering

    NASA Technical Reports Server (NTRS)

    Jeon, Byeungwoo; Landgrebe, D. A.

    1992-01-01

    An absolute classification algorithm is proposed in which the class definition through training samples or otherwise is required only for a particular class of interest. The absolute classification is considered as a problem of unsupervised clustering when one cluster is known initially. The definitions and statistics of the other classes are automatically developed through the weighted unsupervised clustering procedure, which is developed to keep the cluster corresponding to the class of interest from losing its identity as the class of interest. Once all the classes are developed, a conventional relative classifier such as the maximum-likelihood classifier is used in the classification.

  4. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    NASA Astrophysics Data System (ADS)

    Bártová, H.; Kučera, J.; Musílek, L.; Trojek, T.

    2014-11-01

    In order to evaluate the age from the equivalent dose and to obtain an optimized and efficient procedure for thermoluminescence (TL) dating, it is necessary to obtain the values of both the internal and the external dose rates from dated samples and from their environment. The measurements described and compared in this paper refer to bricks from historic buildings and a fine-grain dating method. The external doses are therefore negligible, if the samples are taken from a sufficient depth in the wall. However, both the alpha dose rate and the beta and gamma dose rates must be taken into account in the internal dose. The internal dose rate to fine-grain samples is caused by the concentrations of natural radionuclides 238U, 235U, 232Th and members of their decay chains, and by 40K concentrations. Various methods can be used for determining trace concentrations of these natural radionuclides and their contributions to the dose rate. The dose rate fraction from 238U and 232Th can be calculated, e.g., from the alpha count rate, or from the concentrations of 238U and 232Th, measured by neutron activation analysis (NAA). The dose rate fraction from 40K can be calculated from the concentration of potassium measured, e.g., by X-ray fluorescence analysis (XRF) or by NAA. Alpha counting and XRF are relatively simple and are accessible for an ordinary laboratory. NAA can be considered as a more accurate method, but it is more demanding regarding time and costs, since it needs a nuclear reactor as a neutron source. A comparison of these methods allows us to decide whether the time- and cost-saving simpler techniques introduce uncertainty that is still acceptable.

  5. Absolute flux calibration of optical spectrophotometric standard stars

    NASA Technical Reports Server (NTRS)

    Colina, Luis; Bohlin, Ralph C.

    1994-01-01

    A method based on Landolt photometry in B and V is developed to correct for a wavelength independent offset of the absolute flux level of optical spectrophotometric standards. The method is based on synthetic photometry techniques in B and V and is accurate to approximately 1%. The correction method is verified by Hubble Space Telescope Faint Object Spectrograph absolute fluxes for five calibration stars, which agree with Landolt photometry to 0.5% in B and V.

  6. Reconstructing the paleoseismic history of the Priene-Sazli Fault using 36Cl cosmogenic nuclide dating method, Western Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Mozafari Amiri, Nasim; Sümer, Ökmen; Tikhomirov, Dmitry; Özkaymak, Çaǧlar; Ivy-Ochs, Susan; Uzel, Bora; Vockenhuber, Christof; Sözbilir, Hasan; Akçar, Naki

    2014-05-01

    The 300-km wide West Anatolian Extensional Province is one of the regions of intense seismic activity in the world within the Alpine-Himalayan belt. Deformation pattern in the area is controlled by three major E-W trending graben systems of Gediz, Küçük Menderes and Büyük Menderes which have been formed as a result of roughly N-S extensional tectonic regime since the early Miocene. These graben systems show evidences of surface faulting during the Pleistocene-Holocene and are geomorphologically characterized by well-exposed limestone normal fault scarps with a relief of tens of meters and well-preserved slickenlines. Since limestones are resistant to weathering, the limestone scarps can efficiently record several past earthquakes. Cosmogenic 36Cl is the only element to identify and date the rupture events. Each rupture causes exposure of previously buried section of the scarp to the surface. Accordingly, due to being well enough exposed to cosmic rays, accumulation of 36Cl accelerates during period of quiescence. Thus, distribution of measured 36Cl concentrations can be applied to investigate periods of seismic activity and inactivity and also to calculate the vertical displacement along the fault plane in association with each rupture. In this study, we focus on the Priene-Sazli Fault, located on the most western part of Büyük Menderes graben. Along the active fault zone, well exposed archaeological sites (e.g. Priene) have been discovered, where destructive historical earthquakes have left evidence of ancient damages in the historical period and during the 20th century. The Priene-Sazli Fault caused the July 16, 1955 Söke-Balat earthquake (M=6.8) with fault-plane solution indicating of normal southeast downthrow along with subsidiary dextral motion. We collected 117 samples from four continuous strips on the Priene-Sazli Fault to measure 36Cl concentrations. We used a new Matlab code to identify the significant ruptures and their timing. Our preliminary

  7. The Dating Game, Survivor, and Other War Games: Interesting, Enjoyable and Effective Methods for Conducting Collaborative Research

    DTIC Science & Technology

    2002-01-01

    techniques developed by the Naval War College’s Decision Strategies Department (DSD), and how these methods and techniques have allowed the DSD to meet the...Effective Methods for Conducting Collaborative Research 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval War College,Decision Strategies Dept,686 Cushing

  8. A double-spike method for K-Ar measurement: A technique for high precision in situ dating on Mars and other planetary surfaces

    NASA Astrophysics Data System (ADS)

    Farley, K. A.; Hurowitz, J. A.; Asimow, P. D.; Jacobson, N. S.; Cartwright, J. A.

    2013-06-01

    A new method for K-Ar dating using a double isotope dilution technique is proposed and demonstrated. The method is designed to eliminate known difficulties facing in situ dating on planetary surfaces, especially instrument complexity and power availability. It may also have applicability in some terrestrial dating applications. Key to the method is the use of a solid tracer spike enriched in both 39Ar and 41K. When mixed with lithium borate flux in a Knudsen effusion cell, this tracer spike and a sample to be dated can be successfully fused and degassed of Ar at <1000 °C. The evolved 40Ar∗/39Ar ratio can be measured to high precision using noble gas mass spectrometry. After argon measurement the sample melt is heated to a slightly higher temperature (˜1030 °C) to volatilize potassium, and the evolved 39K/41K ratio measured by Knudsen effusion mass spectrometry. Combined with the known composition of the tracer spike, these two ratios define the K-Ar age using a single sample aliquot and without the need for extreme temperature or a mass determination. In principle the method can be implemented using a single mass spectrometer. Experiments indicate that quantitative extraction of argon from a basalt sample occurs at a sufficiently low temperature that potassium loss in this step is unimportant. Similarly, potassium isotope ratios measured in the Knudsen apparatus indicate good sample-spike equilibration and acceptably small isotopic fractionation. When applied to a flood basalt from the Viluy Traps, Siberia, a K-Ar age of 351 ± 19 Ma was obtained, a result within 1% of the independently known age. For practical reasons this measurement was made on two separate mass spectrometers, but a scheme for combining the measurements in a single analytical instrument is described. Because both parent and daughter are determined by isotope dilution, the precision on K-Ar ages obtained by the double isotope dilution method should routinely approach that of a pair of

  9. Absolute transition probabilities of phosphorus.

    NASA Technical Reports Server (NTRS)

    Miller, M. H.; Roig, R. A.; Bengtson, R. D.

    1971-01-01

    Use of a gas-driven shock tube to measure the absolute strengths of 21 P I lines and 126 P II lines (from 3300 to 6900 A). Accuracy for prominent, isolated neutral and ionic lines is estimated to be 28 to 40% and 18 to 30%, respectively. The data and the corresponding theoretical predictions are examined for conformity with the sum rules.-

  10. Relativistic Absolutism in Moral Education.

    ERIC Educational Resources Information Center

    Vogt, W. Paul

    1982-01-01

    Discusses Emile Durkheim's "Moral Education: A Study in the Theory and Application of the Sociology of Education," which holds that morally healthy societies may vary in culture and organization but must possess absolute rules of moral behavior. Compares this moral theory with current theory and practice of American educators. (MJL)

  11. Absolute Standards for Climate Measurements

    NASA Astrophysics Data System (ADS)

    Leckey, J.

    2016-10-01

    In a world of changing climate, political uncertainty, and ever-changing budgets, the benefit of measurements traceable to SI standards increases by the day. To truly resolve climate change trends on a decadal time scale, on-orbit measurements need to be referenced to something that is both absolute and unchanging. One such mission is the Climate Absolute Radiance and Refractivity Observatory (CLARREO) that will measure a variety of climate variables with an unprecedented accuracy to definitively quantify climate change. In the CLARREO mission, we will utilize phase change cells in which a material is melted to calibrate the temperature of a blackbody that can then be observed by a spectrometer. A material's melting point is an unchanging physical constant that, through a series of transfers, can ultimately calibrate a spectrometer on an absolute scale. CLARREO consists of two primary instruments: an infrared (IR) spectrometer and a reflected solar (RS) spectrometer. The mission will contain orbiting radiometers with sufficient accuracy to calibrate other space-based instrumentation and thus transferring the absolute traceability. The status of various mission options will be presented.

  12. Absolute and relative dosimetry for ELIMED

    NASA Astrophysics Data System (ADS)

    Cirrone, G. A. P.; Cuttone, G.; Candiano, G.; Carpinelli, M.; Leonora, E.; Lo Presti, D.; Musumarra, A.; Pisciotta, P.; Raffaele, L.; Randazzo, N.; Romano, F.; Schillaci, F.; Scuderi, V.; Tramontana, A.; Cirio, R.; Marchetto, F.; Sacchi, R.; Giordanengo, S.; Monaco, V.

    2013-07-01

    The definition of detectors, methods and procedures for the absolute and relative dosimetry of laser-driven proton beams is a crucial step toward the clinical use of this new kind of beams. Hence, one of the ELIMED task, will be the definition of procedures aiming to obtain an absolute dose measure at the end of the transport beamline with an accuracy as close as possible to the one required for clinical applications (i.e. of the order of 5% or less). Relative dosimetry procedures must be established, as well: they are necessary in order to determine and verify the beam dose distributions and to monitor the beam fluence and the energetic spectra during irradiations. Radiochromic films, CR39, Faraday Cup, Secondary Emission Monitor (SEM) and transmission ionization chamber will be considered, designed and studied in order to perform a fully dosimetric characterization of the ELIMED proton beam.

  13. Radiation in archaeometry: archaeological dating

    NASA Astrophysics Data System (ADS)

    Martini, Marco; Sibilia, Emanuela

    2001-06-01

    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.

  14. Measuring the absolute magnetic field using high-Tc SQUID

    NASA Astrophysics Data System (ADS)

    He, D. F.; Itozaki, H.

    2006-06-01

    SQUID normally can only measure the change of magnetic field instead of the absolute value of magnetic field. Using a compensation method, a mobile SQUID, which could keep locked when moving in the earth's magnetic field, was developed. Using the mobile SQUID, it was possible to measure the absolute magnetic field. The absolute value of magnetic field could be calculated from the change of the compensation output when changing the direction of the SQUID in a magnetic field. Using this method and the mobile SQUID, we successfully measured the earth's magnetic field in our laboratory.

  15. L-Carnitine moiety assay: an up-to-date reappraisal covering the commonest methods for various applications.

    PubMed

    Marzo, A; Curti, S

    1997-11-21

    L-Carnitine and its esters are typical endogenous substances. Their homeostatic equilibria are effectively controlled by various mechanisms which include rate-limiting enteral absorption, a multicomponent endogenous pool which is regulated according to a mammillary metabolism, an asymmetric body distribution and a saturable tubular reabsorption process leading to renal thresholds. In formal pharmacokinetic and metabolic investigations, the whole L-carnitine pool should be investigated, owing to the rapid interchange process between the various components of the pool. Free L-carnitine, as well as its acyl esters, must therefore be considered from an analytical viewpoint. L-Carnitine, acetyl-L-carnitine and total L-carnitine (the latter as an expression of the whole pool) can easily be assayed by enzyme or radioenzyme methods. Propionyl-L-carnitine and other esters containing fatty acids with more than three carbon atoms can be assayed using various HPLC approaches. Tandem mass spectrometry is another excellent approach to the assay of carnitine and its short-chain, medium-chain and long-chain esters. As L-carnitine contains a chiral carbon atom, the enantioselectivity of the assays is also considered in this review. Metabolites produced by enteral bacteria, namely tri-, di- and mono-methylamine, gamma-butyrobetaine, along with other systemic metabolites, namely trimethylamine N-oxide and N-nitroso dimethylamine, are very important in quantitative and toxicokinetic terms and require specific assay methods. This review covers the commonest methods of assaying carnitine and its esters, their impurities and pre-systemic and systemic metabolites and gives analytical details and information on their applications in pharmaceutics, biochemistry, pharmacokinetics and toxicokinetics.

  16. Groundwater dating with the helium-tritium method to assess the long-term persistence of pharmaceuticals and their residues in groundwater

    NASA Astrophysics Data System (ADS)

    Massmann, G.; Burke, V.; Hass, U.; Dünnbier, U.

    2012-04-01

    The helium-tritium dating method is based on the analysis of tritium combined with its decay product, the lighter and rare 3He isotope. It was first suggested by Tolstikhin and Kamenskiy (1969) and has since been used in many groundwater studies. We applied the method to date groundwater recharged by bank filtration and former sewage irrigation onto sewage farms in Berlin, Germany, in order to assess the long-term persistence of several organic trace pollutants. In recent years, the occurrence of organic trace pollutants, such as pharmaceuticals and personal care products (PPCPs) as well as their metabolites, in the aquatic environment has been of increasing public and scientific interest (e.g. Schwarzenbach et al., 2006). In (urban) partly closed water cycles like Berlin, poorly biodegradable polar compounds may travel along the water path from wastewater via surface water to the raw water used for drinking water production (Reemtsma et al., 2006). In addition, raw or treated sewage irrigation onto sewage farms and/or agricultural land was common practice in Berlin until the 80s. Combined age dating and trace compound analysis revealed that several phenazone-type compounds (AMDOPH, AMPH, FAA and AAA) as well as a number of psychoactive compounds (meprobamate, pyrithyldione, primidone, and its metabolites phenobarbital and phenylethylmalonamide) are present in three decade old groundwater down gradient of a decommissioned sewage farm in Berlin, while a number of phenazone-type compounds (phenazone, propyphenazone, AMDOPH, AMPH) were present in decade-old bank filtrate. The results prove the long-term-persistence of the respective compounds under anoxic redox conditions, which are prevalent at the investigated sites. At the bank filtration sites, some of the compounds may regionally even be used as time markers for a certain infiltration period and reflect the surface water quality changes of the past few decades.

  17. An Astronomically Dated Standard in 40Ar/39Ar Geochronology?

    NASA Astrophysics Data System (ADS)

    Kuiper, K.; Hilgen, F.; Krijgsman, W.; Wijbrans, J.

    2003-12-01

    The standard geological time scale of Berggren et al. (1995) and Cande and Kent (1995) is calibrated with different absolute dating techniques, i.e. the Plio - Pleistocene relies on astronomical tuning, and older parts of the time scale are based on radio-isotopic (40Ar/39Ar and U/Pb) calibration methods. In the new edition of the standard geological timescale (Lourens et al., to be published in 2004) the entire Neogene will rely on astronomical dating. Therefore, it is of crucial importance that all dating methods produce equivalent absolute ages when the same geological event is dated. The Mediterranean Neogene provides an excellent opportunity to compare different dating methods by isotopic dating (40Ar/39Ar, U/Pb) of volcanic ash layers intercalated in astronomically dated sediments. Here we will show that in spite of potential errors in all methods, we succeeded to intercalibrate the 40Ar/39Ar and astronomical methods, arriving at astronomically calibrated age of 28.24 +/- 0.01 Ma for the in 40Ar/39Ar geochronology commonly used standard FCT sanidine. The advantage of an astronomically calibrated FCT above a K/Ar calibrated standard is a smaller error in the absolute age due to the lack of uncertainties related to 40K and radiogenic 40Ar contents in the primary standard and a decreasing influence of errors in the decay constant (branching ratio is not required). In addition to an astronomically calibrated FCT age we propose to introduce an astronomically dated standard. A direct astronomically dated standard can be regarded as a "primary" standard and does not require intercalibration with other standards, thus reducing analytical (and geological) uncertainties. Ash layers intercalated in sedimentary sequences in the Melilla Basin, Morocco appear to be the most suitable for this purpose. A reliable astronomical time control is available and intercalated ash layers contain sanidine phenocrysts up to 2 mm. Four ash layers are not or barely affected by

  18. Absolute calibration of optical flats

    DOEpatents

    Sommargren, Gary E.

    2005-04-05

    The invention uses the phase shifting diffraction interferometer (PSDI) to provide a true point-by-point measurement of absolute flatness over the surface of optical flats. Beams exiting the fiber optics in a PSDI have perfect spherical wavefronts. The measurement beam is reflected from the optical flat and passed through an auxiliary optic to then be combined with the reference beam on a CCD. The combined beams include phase errors due to both the optic under test and the auxiliary optic. Standard phase extraction algorithms are used to calculate this combined phase error. The optical flat is then removed from the system and the measurement fiber is moved to recombine the two beams. The newly combined beams include only the phase errors due to the auxiliary optic. When the second phase measurement is subtracted from the first phase measurement, the absolute phase error of the optical flat is obtained.

  19. The Absolute Spectrum Polarimeter (ASP)

    NASA Technical Reports Server (NTRS)

    Kogut, A. J.

    2010-01-01

    The Absolute Spectrum Polarimeter (ASP) is an Explorer-class mission to map the absolute intensity and linear polarization of the cosmic microwave background and diffuse astrophysical foregrounds over the full sky from 30 GHz to 5 THz. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r much greater than 1O(raised to the power of { -3}) and Compton distortion y < 10 (raised to the power of{-6}). We describe the ASP instrument and mission architecture needed to detect the signature of an inflationary epoch in the early universe using only 4 semiconductor bolometers.

  20. Physics of negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Abraham, Eitan; Penrose, Oliver

    2017-01-01

    Negative absolute temperatures were introduced into experimental physics by Purcell and Pound, who successfully applied this concept to nuclear spins; nevertheless, the concept has proved controversial: a recent article aroused considerable interest by its claim, based on a classical entropy formula (the "volume entropy") due to Gibbs, that negative temperatures violated basic principles of statistical thermodynamics. Here we give a thermodynamic analysis that confirms the negative-temperature interpretation of the Purcell-Pound experiments. We also examine the principal arguments that have been advanced against the negative temperature concept; we find that these arguments are not logically compelling, and moreover that the underlying "volume" entropy formula leads to predictions inconsistent with existing experimental results on nuclear spins. We conclude that, despite the counterarguments, negative absolute temperatures make good theoretical sense and did occur in the experiments designed to produce them.

  1. Optomechanics for absolute rotation detection

    NASA Astrophysics Data System (ADS)

    Davuluri, Sankar

    2016-07-01

    In this article, we present an application of optomechanical cavity for the absolute rotation detection. The optomechanical cavity is arranged in a Michelson interferometer in such a way that the classical centrifugal force due to rotation changes the length of the optomechanical cavity. The change in the cavity length induces a shift in the frequency of the cavity mode. The phase shift corresponding to the frequency shift in the cavity mode is measured at the interferometer output to estimate the angular velocity of absolute rotation. We derived an analytic expression to estimate the minimum detectable rotation rate in our scheme for a given optomechanical cavity. Temperature dependence of the rotation detection sensitivity is studied.

  2. Improved spatial resolution for U-series dating of opal at Yucca Mountain, Nevada, USA, using ion-microprobe and microdigestion methods

    USGS Publications Warehouse

    Paces, J.B.; Neymark, L.A.; Wooden, J.L.; Persing, H.M.

    2004-01-01

    Two novel methods of in situ isotope analysis, ion microprobe and microdigestion, were used for 230Th/U and 234U/238U dating of finely laminated opal hemispheres formed in unsaturated felsic tuff at Yucca Mountain, Nevada, proposed site for a high-level radioactive waste repository. Both methods allow analysis of layers as many as several orders of magnitude thinner than standard methods using total hemisphere digestion that were reported previously. Average growth rates calculated from data at this improved spatial resolution verified that opal grew at extremely slow rates over the last million years. Growth rates of 0.58 and 0.69 mm/m.y. were obtained for the outer 305 and 740 ??m of two opal hemispheres analyzed by ion microprobe, and 0.68 mm/m.y. for the outer 22 ??m of one of these same hemispheres analyzed by sequential microdigestion. These Pleistocene growth rates are 2 to 10 times slower than those calculated for older secondary calcite and silica mineral coatings deposited over the last 5 to 10 m.y. dated by the U-Pb method and may reflect differences between Miocene and Pleistocene seepage flux. The microdigestion data also imply that opal growth rates may have varied over the last 40 k.y. These data are the first indication that growth rates and associated seepage in the proposed repository horizon may correlate with changes in late Pleistocene climate, involving faster growth during wetter, cooler climates (glacial maximum), slower growth during transition climates, and no growth during the most arid climate (modern). Data collected at this refined spatial scale may lead to a better understanding of the hydrologic variability expected within the thick unsaturated zone at Yucca Mountain over the time scale of interest for radioactive waste isolation. ?? 2004 Elsevier Ltd.

  3. Hydration rind dates rhyolite flows.

    PubMed

    Friedman, I

    1968-02-23

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago.

  4. Ionium dating of igneous rocks.

    PubMed

    Kigoshi, K

    1967-05-19

    Local fractionation of uranium and thorium, between minerals within a sample of igneous rock at the time of crystallization, makes it possible to date its solidification by use of ionium and uranium. Results on samples of granite, pumice, and lava suggest that this method of dating is reliable.

  5. Radiocarbon Dating: An Annotated Bibliography.

    ERIC Educational Resources Information Center

    Fortine, Suellen

    This selective annotated bibliography covers various sources of information on the radiocarbon dating method, including journal articles, conference proceedings, and reports, reflecting the most important and useful sources of the last 25 years. The bibliography is divided into five parts--general background on radiocarbon, radiocarbon dating,…

  6. Hydration rind dates rhyolite flows

    USGS Publications Warehouse

    Friedman, I.

    1968-01-01

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago.

  7. Precise determination of the absolute isotopic abundance ratio and the atomic weight of chlorine in three international reference materials by the positive thermal ionization mass spectrometer-Cs2Cl+-graphite method.

    PubMed

    Wei, Hai-Zhen; Jiang, Shao-Yong; Xiao, Ying-Kai; Wang, Jun; Lu, Hai; Wu, Bin; Wu, He-Pin; Li, Qing; Luo, Chong-Guang

    2012-12-04

    Because the variation in chlorine isotopic abundances of naturally occurring chlorine bearing substances is significant, the IUPAC Inorganic Chemistry Division, Commission on Isotopic Abundances and Atomic Weights (CIAAW-IUPAC) decided that the uncertainty of atomic weight of chlorine (A(r)(Cl)) should be increased so that the implied range was related to terrestrial variability in 1999 (Coplen, T. B. Atomic weights of the elements 1999 (IUPAC Technical Report), Pure Appl. Chem.2001, 73(4), 667-683; and then, it emphasized that the standard atomic weights of ten elements including chlorine were not constants of nature but depend upon the physical, chemical, and nuclear history of the materials in 2009 (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396). According to the agreement by CIAAW that an atomic weight could be defined for one specified sample of terrestrial origin (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396), the absolute isotope ratios and atomic weight of chlorine in standard reference materials (NIST 975, NIST 975a, ISL 354) were accurately determined using the high-precision positive thermal ionization mass spectrometer (PTIMS)-Cs(2)Cl(+)-graphite method. After eliminating the weighing error caused from evaporation by designing a special weighing container and accurately determining the chlorine contents in two highly enriched Na(37)Cl and Na(35)Cl salts by the current constant coulometric titration, one series of gravimetric synthetic mixtures prepared from two highly enriched Na(37)Cl and Na(35)Cl salts was used to calibrate two thermal ionization mass spectrometers in two individual laboratories. The correction factors (i.e., K(37/35) = R(37/35meas)/R(37/35calc)) were obtained from five cycles of iterative calculations on the basis of calculated and determined R((37)Cl/(35)Cl) values in gravimetric synthetic mixtures. The absolute R((37)Cl/(35)Cl) ratios for NIST SRM 975, NIST 975a, and ISL 354 by the precise

  8. A nonmusical paradigm for identifying absolute pitch possessors

    NASA Astrophysics Data System (ADS)

    Ross, David A.; Olson, Ingrid R.; Marks, Lawrence E.; Gore, John C.

    2004-09-01

    The ability to identify and reproduce sounds of specific frequencies is remarkable and uncommon. The etiology and defining characteristics of this skill, absolute pitch (AP), have been very controversial. One theory suggests that AP requires a specific type of early musical training and that the ability to encode and remember tones depends on these learned musical associations. An alternate theory argues that AP may be strongly dependent on hereditary factors and relatively independent of musical experience. To date, it has been difficult to test these hypotheses because all previous paradigms for identifying AP have required subjects to employ knowledge of musical nomenclature. As such, these tests are insensitive to the possibility of discovering AP in either nonmusicians or musicians of non-Western training. Based on previous literature in pitch memory, a paradigm is presented that is intended to distinguish between AP possessors and nonpossessors independent of the subjects' musical experience. The efficacy of this method is then tested with 20 classically defined AP possessors and 22 nonpossessors. Data from these groups strongly support the validity of the paradigm. The use of a nonmusical paradigm to identify AP may facilitate research into many aspects of this phenomenon.

  9. Early Acheulean technology in the Rietputs Formation, South Africa, dated with cosmogenic nuclides.

    PubMed

    Gibbon, Ryan J; Granger, Darryl E; Kuman, Kathleen; Partridge, Timothy C

    2009-02-01

    An absolute dating technique based on the build-up and decay of (26)Al and (10)Be in the mineral quartz provides crucial evidence regarding early Acheulean hominid distribution in South Africa. Cosmogenic nuclide burial dating of an ancient alluvial deposit of the Vaal River (Rietputs Formation) in the western interior of South Africa shows that coarse gravel and sand aggradation there occurred ca 1.57+/-0.22Ma, with individual ages of samples ranging from 1.89+/-0.19 to 1.34+/-0.22Ma. This was followed by aggradation of laminated and cross-bedded fine alluvium at ca 1.26+/-0.10Ma. The Rietputs Formation provides an ideal situation for the use of the cosmogenic nuclide burial dating method, as samples could be obtained from deep mining pits at depths ranging from 7 to 16 meters. Individual dates provide only a minimum age for the stone tool technology preserved within the deposits. Each assemblage represents a time averaged collection. Bifacial tools distributed throughout the coarse gravel and sand unit can be assigned to an early phase of the Acheulean. This is the first absolute radiometric dated evidence for early Acheulean artefacts in South Africa that have been found outside of the early hominid sites of the Gauteng Province. These absolute dates also indicate that handaxe-using hominids inhabited southern Africa as early as their counterparts in East Africa. The simultaneous appearance of the Acheulean in different parts of the continent implies relatively rapid technology development and the widespread use of large cutting tools in the African continent by ca 1.6Ma.

  10. Absolute calibration of optical tweezers

    SciTech Connect

    Viana, N.B.; Mazolli, A.; Maia Neto, P.A.; Nussenzveig, H.M.; Rocha, M.S.; Mesquita, O.N.

    2006-03-27

    As a step toward absolute calibration of optical tweezers, a first-principles theory of trapping forces with no adjustable parameters, corrected for spherical aberration, is experimentally tested. Employing two very different setups, we find generally very good agreement for the transverse trap stiffness as a function of microsphere radius for a broad range of radii, including the values employed in practice, and at different sample chamber depths. The domain of validity of the WKB ('geometrical optics') approximation to the theory is verified. Theoretical predictions for the trapping threshold, peak position, depth variation, multiple equilibria, and 'jump' effects are also confirmed.

  11. Linear ultrasonic motor for absolute gravimeter.

    PubMed

    Jian, Yue; Yao, Zhiyuan; Silberschmidt, Vadim V

    2017-02-01

    Thanks to their compactness and suitability for vacuum applications, linear ultrasonic motors are considered as substitutes for classical electromagnetic motors as driving elements in absolute gravimeters. Still, their application is prevented by relatively low power output. To overcome this limitation and provide better stability, a V-type linear ultrasonic motor with a new clamping method is proposed for a gravimeter. In this paper, a mechanical model of stators with flexible clamping components is suggested, according to a design criterion for clamps of linear ultrasonic motors. After that, an effect of tangential and normal rigidity of the clamping components on mechanical output is studied. It is followed by discussion of a new clamping method with sufficient tangential rigidity and a capability to facilitate pre-load. Additionally, a prototype of the motor with the proposed clamping method was fabricated and the performance tests in vertical direction were implemented. Experimental results show that the suggested motor has structural stability and high dynamic performance, such as no-load speed of 1.4m/s and maximal thrust of 43N, meeting the requirements for absolute gravimeters.

  12. Achieving Climate Change Absolute Accuracy in Orbit

    NASA Technical Reports Server (NTRS)

    Wielicki, Bruce A.; Young, D. F.; Mlynczak, M. G.; Thome, K. J; Leroy, S.; Corliss, J.; Anderson, J. G.; Ao, C. O.; Bantges, R.; Best, F.; Bowman, K.; Brindley, H.; Butler, J. J.; Collins, W.; Dykema, J. A.; Doelling, D. R.; Feldman, D. R.; Fox, N.; Huang, X.; Holz, R.; Huang, Y.; Jennings, D.; Jin, Z.; Johnson, D. G.; Jucks, K.; Kato, S.; Kratz, D. P.; Liu, X.; Lukashin, C.; Mannucci, A. J.; Phojanamongkolkij, N.; Roithmayr, C. M.; Sandford, S.; Taylor, P. C.; Xiong, X.

    2013-01-01

    The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission will provide a calibration laboratory in orbit for the purpose of accurately measuring and attributing climate change. CLARREO measurements establish new climate change benchmarks with high absolute radiometric accuracy and high statistical confidence across a wide range of essential climate variables. CLARREO's inherently high absolute accuracy will be verified and traceable on orbit to Système Internationale (SI) units. The benchmarks established by CLARREO will be critical for assessing changes in the Earth system and climate model predictive capabilities for decades into the future as society works to meet the challenge of optimizing strategies for mitigating and adapting to climate change. The CLARREO benchmarks are derived from measurements of the Earth's thermal infrared spectrum (5-50 micron), the spectrum of solar radiation reflected by the Earth and its atmosphere (320-2300 nm), and radio occultation refractivity from which accurate temperature profiles are derived. The mission has the ability to provide new spectral fingerprints of climate change, as well as to provide the first orbiting radiometer with accuracy sufficient to serve as the reference transfer standard for other space sensors, in essence serving as a "NIST [National Institute of Standards and Technology] in orbit." CLARREO will greatly improve the accuracy and relevance of a wide range of space-borne instruments for decadal climate change. Finally, CLARREO has developed new metrics and methods for determining the accuracy requirements of climate observations for a wide range of climate variables and uncertainty sources. These methods should be useful for improving our understanding of observing requirements for most climate change observations.

  13. In vivo absorption spectroscopy for absolute measurement.

    PubMed

    Furukawa, Hiromitsu; Fukuda, Takashi

    2012-10-01

    In in vivo spectroscopy, there are differences between individual subjects in parameters such as tissue scattering and sample concentration. We propose a method that can provide the absolute value of a particular substance concentration, independent of these individual differences. Thus, it is not necessary to use the typical statistical calibration curve, which assumes an average level of scattering and an averaged concentration over individual subjects. This method is expected to greatly reduce the difficulties encountered during in vivo measurements. As an example, for in vivo absorption spectroscopy, the method was applied to the reflectance measurement in retinal vessels to monitor their oxygen saturation levels. This method was then validated by applying it to the tissue phantom under a variety of absorbance values and scattering efficiencies.

  14. Ore genesis dating: implication of Sm-Nd method using sulfide minerals for mafic-ultramafic layered intrusions of Fennoscandian Shield

    NASA Astrophysics Data System (ADS)

    Serov, Pavel; Bayanova, Tamara; Steshenko, Ekaterina; Ekimova, Nadezhda

    2015-04-01

    The main method of dating the ore process was the Re-Os method of sulfides (Luck, Allegre, 1983; Walker et. al., 1991). However, studies of Re-Os systematics of sulfide minerals do not always give the correct ages and showing the disturbances of the Re-Os systematics. At the same time, Sm-Nd age of sulfides in good agreement with the U-Pb dating on zircon and baddeleyite and suggests that the Sm-Nd system of sulfides is more resistant to secondary alteration processes. Our studies have shown that along with rock-forming, ore minerals (sulfides) can be used to determine the ore genesis time of industrially important geological sites, since exactly with the sulfides the industry Pt-Pd mineralization is closely connected. In to Sm-Nd measurements steadily introduce new minerals-geochronometers (i.e. titanite, burbancite, eudialite etc.). Of these, sulfides of PGE-bearing layered intrusions are quite important in terms of dating the process of ore origin. Studying the REE distribution in the sulfides of MOR hydrothermal sources has shown possible REE presence in the sulfide lattice (Rimskaya-Korsakova et. al., 2003). These are difficult to carry out because the concentrations of Sm and Nd isotopes in sulfides are much lower than those in chondrites (Rimskaya-Korsakova et. al., 2003). In (Kong et. al., 2000) sulfides from two metamorphosed chondrites were studied by instrumental neutron activation analysis (INAA) and ion probe. As shown, the level of REE in the sulfide phase determined by the ion probe is quite similar to that obtained by INAA. Although the concentrations of REE in the enstatite and the Fe, Si, Cr-rich inclusions are comparable to those in sulfide, estimates based on mass balance calculations show that the silicate inclusions would not noticeably contribute to the REE budget in sulfides (Kong et. al., 2000). For the first time in Russian geochemistry laboratories using sulfide and rock-forming minerals and WR in Sm-Nd method have been dated impregnated

  15. Monochromator-Based Absolute Calibration of Radiation Thermometers

    NASA Astrophysics Data System (ADS)

    Keawprasert, T.; Anhalt, K.; Taubert, D. R.; Hartmann, J.

    2011-08-01

    A monochromator integrating-sphere-based spectral comparator facility has been developed to calibrate standard radiation thermometers in terms of the absolute spectral radiance responsivity, traceable to the PTB cryogenic radiometer. The absolute responsivity calibration has been improved using a 75 W xenon lamp with a reflective mirror and imaging optics to a relative standard uncertainty at the peak wavelength of approximately 0.17 % ( k = 1). Via a relative measurement of the out-of-band responsivity, the spectral responsivity of radiation thermometers can be fully characterized. To verify the calibration accuracy, the absolutely calibrated radiation thermometer is used to measure Au and Cu freezing-point temperatures and then to compare the obtained results with the values obtained by absolute methods, resulting in T - T 90 values of +52 mK and -50 mK for the gold and copper fixed points, respectively.

  16. Why to compare absolute numbers of mitochondria.

    PubMed

    Schmitt, Sabine; Schulz, Sabine; Schropp, Eva-Maria; Eberhagen, Carola; Simmons, Alisha; Beisker, Wolfgang; Aichler, Michaela; Zischka, Hans

    2014-11-01

    Prompted by pronounced structural differences between rat liver and rat hepatocellular carcinoma mitochondria, we suspected these mitochondrial populations to differ massively in their molecular composition. Aiming to reveal these mitochondrial differences, we came across the issue on how to normalize such comparisons and decided to focus on the absolute number of mitochondria. To this end, fluorescently stained mitochondria were quantified by flow cytometry. For rat liver mitochondria, this approach resulted in mitochondrial protein contents comparable to earlier reports using alternative methods. We determined similar protein contents for rat liver, heart and kidney mitochondria. In contrast, however, lower protein contents were determined for rat brain mitochondria and for mitochondria from the rat hepatocellular carcinoma cell line McA 7777. This result challenges mitochondrial comparisons that rely on equal protein amounts as a typical normalization method. Exemplarily, we therefore compared the activity and susceptibility toward inhibition of complex II of rat liver and hepatocellular carcinoma mitochondria and obtained significant discrepancies by either normalizing to protein amount or to absolute mitochondrial number. Importantly, the latter normalization, in contrast to the former, demonstrated a lower complex II activity and higher susceptibility toward inhibition in hepatocellular carcinoma mitochondria compared to liver mitochondria. These findings demonstrate that solely normalizing to protein amount may obscure essential molecular differences between mitochondrial populations.

  17. Standardization of the cumulative absolute velocity

    SciTech Connect

    O'Hara, T.F.; Jacobson, J.P. )

    1991-12-01

    EPRI NP-5930, A Criterion for Determining Exceedance of the Operating Basis Earthquake,'' was published in July 1988. As defined in that report, the Operating Basis Earthquake (OBE) is exceeded when both a response spectrum parameter and a second damage parameter, referred to as the Cumulative Absolute Velocity (CAV), are exceeded. In the review process of the above report, it was noted that the calculation of CAV could be confounded by time history records of long duration containing low (nondamaging) acceleration. Therefore, it is necessary to standardize the method of calculating CAV to account for record length. This standardized methodology allows consistent comparisons between future CAV calculations and the adjusted CAV threshold value based upon applying the standardized methodology to the data set presented in EPRI NP-5930. The recommended method to standardize the CAV calculation is to window its calculation on a second-by-second basis for a given time history. If the absolute acceleration exceeds 0.025g at any time during each one second interval, the earthquake records used in EPRI NP-5930 have been reanalyzed and the adjusted threshold of damage for CAV was found to be 0.16g-set.

  18. Cosmology with negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Vieira, J. P. P.; Byrnes, Christian T.; Lewis, Antony

    2016-08-01

    Negative absolute temperatures (NAT) are an exotic thermodynamical consequence of quantum physics which has been known since the 1950's (having been achieved in the lab on a number of occasions). Recently, the work of Braun et al. [1] has rekindled interest in negative temperatures and hinted at a possibility of using NAT systems in the lab as dark energy analogues. This paper goes one step further, looking into the cosmological consequences of the existence of a NAT component in the Universe. NAT-dominated expanding Universes experience a borderline phantom expansion (w < -1) with no Big Rip, and their contracting counterparts are forced to bounce after the energy density becomes sufficiently large. Both scenarios might be used to solve horizon and flatness problems analogously to standard inflation and bouncing cosmologies. We discuss the difficulties in obtaining and ending a NAT-dominated epoch, and possible ways of obtaining density perturbations with an acceptable spectrum.

  19. Laboratory for Radiokrypton Dating

    NASA Astrophysics Data System (ADS)

    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.

  20. Toward The Absolute Age of M92 With MIST

    NASA Astrophysics Data System (ADS)

    Choi, Jieun; Conroy, Charlie; Dotter, Aaron; Weisz, Daniel; Rosenfield, Philip; Dolphin, Andrew

    2016-08-01

    Globular clusters provide a fundamental link between stars and galaxies. For example, it has been suggested that ultra faint dwarf galaxies formed all of their stars prior to the epoch of reionization, but this conclusion hinges entirely on the striking similarity of their stellar populations to the ancient, metal-poor globular cluster M92. The accurate measurement of absolute ages of ancient globular clusters therefore has direct implications for the formation histories of the smallest galaxies in the Universe. However, a reliable determination of the absolute ages of globular clusters has proven to be a challenge due to uncertainties in stellar physics and complications in how the models are compared to observations. I will present preliminary results from a comprehensive study to measure the absolute age of M92 using high-quality HST archival imaging data. We pair our new MESA Isochrones and Stellar Tracks (MIST) models with a full CMD fitting framework to jointly fit multi-color CMDs, taking into account the uncertainties in abundances, distance, and stellar physics. The goal of this project is two-fold. First, we aim to provide the most secure absolute age of M92 to date with robustly estimated uncertainties. Second, we explore and quantify the degeneracies between uncertain physical quantities and model variables, such as the distance, mixing-length-alpha parameter, and helium abundance, with the ultimate goal of better constraining these unknowns with data from ongoing and future surveys such as K2, Gaia, TESS, JWST, and WFIRST.

  1. Teaching the Mathematics of Radioactive Dating.

    ERIC Educational Resources Information Center

    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)

  2. Large-Scale Measurement of Absolute Protein Glycosylation Stoichiometry.

    PubMed

    Sun, Shisheng; Zhang, Hui

    2015-07-07

    Protein glycosylation is one of the most important protein modifications. Glycosylation site occupancy alteration has been implicated in human diseases and cancers. However, current glycoproteomic methods focus on the identification and quantification of glycosylated peptides and glycosylation sites but not glycosylation occupancy or glycoform stoichiometry. Here we describe a method for large-scale determination of the absolute glycosylation stoichiometry using three independent relative ratios. Using this method, we determined 117 absolute N-glycosylation occupancies in OVCAR-3 cells. Finally, we investigated the possible functions and the determinants for partial glycosylation.

  3. Absolute measurements of the uranium concentration in thick samples using fission-track detectors

    NASA Astrophysics Data System (ADS)

    Enkelmann, Eva; Jonckheere, Raymond; Ratschbacher, Lothar

    2005-04-01

    We propose an improved equation for calculating the uranium concentration in thick samples based on induced fission-track counts in an external detector that takes into consideration (1) the fission-fragment ranges in the sample and external detector, (2) the etchable track length and (3) the track counting efficiency in the external detector. The values of these parameters have been determined by calculation and experiment and are shown to have a significant effect on the calculated uranium concentrations. The new equation was tested by calculating the uranium concentrations in standard uranium glasses (CN-5; IRMM-540R) and apatite samples (Durango; horse tooth) in which the uranium content was also determined with independent methods (INAA; ENAA; TIMS). The results show that: (1) accurate measurements with the fission-track method are feasible within a broad range of uranium concentrations and (2) uranium determinations based on standards are only accurate if the standard and sample are made of the same material. Because the absolute fission-tack dating method is also based on accurate thermal neutron fluence measurements and similar correction factors for the track registration and counting efficiencies, this study provides a strong endorsement for the fact that absolute fission-track ages are accurate.

  4. MAGSAT: Vector magnetometer absolute sensor alignment determination

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.

    1981-01-01

    A procedure is described for accurately determining the absolute alignment of the magnetic axes of a triaxial magnetometer sensor with respect to an external, fixed, reference coordinate system. The method does not require that the magnetic field vector orientation, as generated by a triaxial calibration coil system, be known to better than a few degrees from its true position, and minimizes the number of positions through which a sensor assembly must be rotated to obtain a solution. Computer simulations show that accuracies of better than 0.4 seconds of arc can be achieved under typical test conditions associated with existing magnetic test facilities. The basic approach is similar in nature to that presented by McPherron and Snare (1978) except that only three sensor positions are required and the system of equations to be solved is considerably simplified. Applications of the method to the case of the MAGSAT Vector Magnetometer are presented and the problems encountered discussed.

  5. Direct dating of human fossils.

    PubMed

    Grün, Rainer

    2006-01-01

    The methods that can be used for the direct dating of human remains comprise of radiocarbon, U-series, electron spin resonance (ESR), and amino acid racemization (AAR). This review gives an introduction to these methods in the context of dating human bones and teeth. Recent advances in ultrafiltration techniques have expanded the dating range of radiocarbon. It now seems feasible to reliably date bones up to 55,000 years. New developments in laser ablation mass spectrometry permit the in situ analysis of U-series isotopes, thus providing a rapid and virtually non-destructive dating method back to about 300,000 years. This is of particular importance when used in conjunction with non-destructive ESR analysis. New approaches in AAR analysis may lead to a renaissance of this method. The potential and present limitations of these direct dating techniques are discussed for sites relevant to the reconstruction of modern human evolution, including Florisbad, Border Cave, Tabun, Skhul, Qafzeh, Vindija, Banyoles, and Lake Mungo.

  6. 210Pb dating

    USGS Publications Warehouse

    Swarzenski, Peter W.

    2014-01-01

    Roughly fifty years ago, a small group of scientists from Belgium and the United States, trying to better constrain ice sheet accumulation rates, attempted to apply what was then know about environmental lead as a potential geochronometer. Thus Goldberg (1963) developed the first principles of the 210Pb dating method, which was soon followed by a paper by Crozaz et al. (1964), who examined accumulation history of Antarctic snow using 210Pb. Shortly thereafter, Koide et al. (1972, 1973) adapted this technique to unravel sediment deposition and accumulation records in deep-sea environments. Serendipitously, they chose to work in a deep basin off California, where an independent and robust age model had already been developed. Krishanswami et al. (1971) extended the use of this technique to lacustrine deposits to reconstruct depositional histories of lake sediment, and maybe more importantly, contaminant inputs and burial. Thus, the powerful tool for dating recent (up to about one century old) sediment deposits was established and soon widely adopted. Today almost all oceanographic or limnologic studies that address recent depositional reconstructions employ 210Pb as one of several possible geochronometers (Andrews et al., 2009; Gale, 2009; Baskaran, 2011; Persson and Helms, 2011). This paper presents a short overview of the principles of 210Pb dating and provides a few examples that illustrate the utility of this tracer in contrasting depositional systems. Potential caveats and uncertainties (Appleby et al., 1986; Binford, 1990; Binford et al., 1993; Smith, 2001; Hancock et al., 2002) inherent to the use and interpretation of 210Pb-derived age-models are also introduced. Recommendations as to best practices for most reliable uses and reporting are presented in the summary.

  7. A Method for Application of Classification Tree Models to Map Aquatic Vegetation Using Remotely Sensed Images from Different Sensors and Dates

    PubMed Central

    Jiang, Hao; Zhao, Dehua; Cai, Ying; An, Shuqing

    2012-01-01

    In previous attempts to identify aquatic vegetation from remotely-sensed images using classification trees (CT), the images used to apply CT models to different times or locations necessarily originated from the same satellite sensor as that from which the original images used in model development came, greatly limiting the application of CT. We have developed an effective normalization method to improve the robustness of CT models when applied to images originating from different sensors and dates. A total of 965 ground-truth samples of aquatic vegetation types were obtained in 2009 and 2010 in Taihu Lake, China. Using relevant spectral indices (SI) as classifiers, we manually developed a stable CT model structure and then applied a standard CT algorithm to obtain quantitative (optimal) thresholds from 2009 ground-truth data and images from Landsat7-ETM+, HJ-1B-CCD, Landsat5-TM and ALOS-AVNIR-2 sensors. Optimal CT thresholds produced average classification accuracies of 78.1%, 84.7% and 74.0% for emergent vegetation, floating-leaf vegetation and submerged vegetation, respectively. However, the optimal CT thresholds for different sensor images differed from each other, with an average relative variation (RV) of 6.40%. We developed and evaluated three new approaches to normalizing the images. The best-performing method (Method of 0.1% index scaling) normalized the SI images using tailored percentages of extreme pixel values. Using the images normalized by Method of 0.1% index scaling, CT models for a particular sensor in which thresholds were replaced by those from the models developed for images originating from other sensors provided average classification accuracies of 76.0%, 82.8% and 68.9% for emergent vegetation, floating-leaf vegetation and submerged vegetation, respectively. Applying the CT models developed for normalized 2009 images to 2010 images resulted in high classification (78.0%–93.3%) and overall (92.0%–93.1%) accuracies. Our results suggest

  8. Food Product Dating

    MedlinePlus

    ... of date you might find on a meat, poultry, or egg product label. Are dates required on ... is not required by Federal regulations. For meat, poultry, and egg products under the jurisdiction of the ...

  9. An estimate of global absolute dynamic topography

    NASA Technical Reports Server (NTRS)

    Tai, C.-K.; Wunsch, C.

    1984-01-01

    The absolute dynamic topography of the world ocean is estimated from the largest scales to a short-wavelength cutoff of about 6700 km for the period July through September, 1978. The data base consisted of the time-averaged sea-surface topography determined by Seasat and geoid estimates made at the Goddard Space Flight Center. The issues are those of accuracy and resolution. Use of the altimetric surface as a geoid estimate beyond the short-wavelength cutoff reduces the spectral leakage in the estimated dynamic topography from erroneous small-scale geoid estimates without contaminating the low wavenumbers. Comparison of the result with a similarly filtered version of Levitus' (1982) historical average dynamic topography shows good qualitative agreement. There is quantitative disagreement, but it is within the estimated errors of both methods of calculation.

  10. Absolute GPS Positioning Using Genetic Algorithms

    NASA Astrophysics Data System (ADS)

    Ramillien, G.

    A new inverse approach for restoring the absolute coordinates of a ground -based station from three or four observed GPS pseudo-ranges is proposed. This stochastic method is based on simulations of natural evolution named genetic algorithms (GA). These iterative procedures provide fairly good and robust estimates of the absolute positions in the Earth's geocentric reference system. For comparison/validation, GA results are compared to the ones obtained using the classical linearized least-square scheme for the determination of the XYZ location proposed by Bancroft (1985) which is strongly limited by the number of available observations (i.e. here, the number of input pseudo-ranges must be four). The r.m.s. accuracy of the non -linear cost function reached by this latter method is typically ~10-4 m2 corresponding to ~300-500-m accuracies for each geocentric coordinate. However, GA can provide more acceptable solutions (r.m.s. errors < 10-5 m2), even when only three instantaneous pseudo-ranges are used, such as a lost of lock during a GPS survey. Tuned GA parameters used in different simulations are N=1000 starting individuals, as well as Pc=60-70% and Pm=30-40% for the crossover probability and mutation rate, respectively. Statistical tests on the ability of GA to recover acceptable coordinates in presence of important levels of noise are made simulating nearly 3000 random samples of erroneous pseudo-ranges. Here, two main sources of measurement errors are considered in the inversion: (1) typical satellite-clock errors and/or 300-metre variance atmospheric delays, and (2) Geometrical Dilution of Precision (GDOP) due to the particular GPS satellite configuration at the time of acquisition. Extracting valuable information and even from low-quality starting range observations, GA offer an interesting alternative for high -precision GPS positioning.

  11. Accurate dating of fluvial deposits in the Lateglacial Niers Valley system (Germany) using a multiple dating strategy

    NASA Astrophysics Data System (ADS)

    Hoek, W. Z.; Kasse, C.; Peeters, J.; Wallinga, J.

    2009-04-01

    The River Rhine occupied the Niers Valley (Germany) from the Saalian Glaciation (MIS 6) until the Early Holocene (Kasse et al., Journal of Quaternary Science 2005). The fluvial landscape of the time of abandonment has been exceptionally well preserved, leaving a series of cut-off meanders and residual channels. This unique preservation provides the possibility to investigate Late Weichselian fluvial dynamics of the River Rhine. We combined several dating techniques to accurately determine the age of the deposits. We developed a sampling strategy based on detailed field survey and cross sectioning. 1) The geomorphological relationships of the cut-off meanders gave a relative age for the successive stages of meandering. 2) The occurrence of Laacher See Pumice in the point bar deposits gave a maximum age for these deposits. 3) Optically Stimulated Luminescence (OSL)-dating on sandy point bar and channel-fill deposits yielded absolute ages for active meandering and channel abandonment. 4) AMS-14C dates on terrestrial macrofossils from the basal fills of the residual channels yielded minimum ages for abandonment. 5) Biostratigraphy of the organic channel fills using palynology gave a relative chronology, which could be linked to the well-dated regional biostratigraphy of the nearby Netherlands and is cross-checked by additional AMS-14C dates. By combining these dating techniques we obtained a firm chronological framework that allows linkage to climate records and above the cross-validation of the different dating techniques. All techniques gave consistent ages that confirm the Lateglacial age and Early Holocene abandonment of the Niers Valley by the River Rhine. Palynology and 14C-dating on the channels fills supported the relative chronology indicated by the cross-cut relationships. The presence of the Laacher See Pumice in the point bar deposits, which has an unambiguous age of 12.9 ka cal. BP concurs with the organic channel fill ages. Because OSL signals in some

  12. Estimation of Absolute Protein Quantities of Unlabeled Samples by Selected Reaction Monitoring Mass Spectrometry*

    PubMed Central

    Ludwig, Christina; Claassen, Manfred; Schmidt, Alexander; Aebersold, Ruedi

    2012-01-01

    For many research questions in modern molecular and systems biology, information about absolute protein quantities is imperative. This information includes, for example, kinetic modeling of processes, protein turnover determinations, stoichiometric investigations of protein complexes, or quantitative comparisons of different proteins within one sample or across samples. To date, the vast majority of proteomic studies are limited to providing relative quantitative comparisons of protein levels between limited numbers of samples. Here we describe and demonstrate the utility of a targeting MS technique for the estimation of absolute protein abundance in unlabeled and nonfractionated cell lysates. The method is based on selected reaction monitoring (SRM) mass spectrometry and the “best flyer” hypothesis, which assumes that the specific MS signal intensity of the most intense tryptic peptides per protein is approximately constant throughout a whole proteome. SRM-targeted best flyer peptides were selected for each protein from the peptide precursor ion signal intensities from directed MS data. The most intense transitions per peptide were selected from full MS/MS scans of crude synthetic analogs. We used Monte Carlo cross-validation to systematically investigate the accuracy of the technique as a function of the number of measured best flyer peptides and the number of SRM transitions per peptide. We found that a linear model based on the two most intense transitions of the three best flying peptides per proteins (TopPep3/TopTra2) generated optimal results with a cross-correlated mean fold error of 1.8 and a squared Pearson coefficient R2 of 0.88. Applying the optimized model to lysates of the microbe Leptospira interrogans, we detected significant protein abundance changes of 39 target proteins upon antibiotic treatment, which correlate well with literature values. The described method is generally applicable and exploits the inherent performance advantages of SRM

  13. Radiocarbon dating of terrestrial carbonates

    USGS Publications Warehouse

    Pigati, Jeffrey S.; Rink, W. Jack; Thompson, Jeroen

    2014-01-01

    Terrestrial carbonates encompass a wide range of materials that potentially could be used for radiocarbon (14C) dating. Biogenic carbonates, including shells and tests of terrestrial and aquatic gastropods, bivalves, ostracodes, and foraminifera, are preserved in a variety of late Quaternary deposits and may be suitable for 14C dating. Primary calcareous deposits (marls, tufa, speleothems) and secondary carbonates (rhizoliths, fracture fill, soil carbonate) may also be targeted for dating when conditions are favorable. This chapter discusses issues that are commonly encountered in 14C dating of terrestrial carbonates, including isotopic disequilibrium and open-system behavior, as well as methods used to determine the reliability of ages derived from these materials. Recent methodological advancements that may improve the accuracy and precision of 14C ages of terrestrial carbonates are also highlighted.

  14. Laboratory for Radiokrypton Dating

    NASA Astrophysics Data System (ADS)

    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

  15. Absolute bioavailability of quinine formulations in Nigeria.

    PubMed

    Babalola, C P; Bolaji, O O; Ogunbona, F A; Ezeomah, E

    2004-09-01

    This study compared the absolute bioavailability of quinine sulphate as capsule and as tablet against the intravenous (i.v.) infusion of the drug in twelve male volunteers. Six of the volunteers received intravenous infusion over 4 h as well as the capsule formulation of the drug in a cross-over manner, while the other six received the tablet formulation. Blood samples were taken at predetermined time intervals and plasma analysed for quinine (QN) using reversed-phase HPLC method. QN was rapidly absorbed after the two oral formulations with average t(max) of 2.67 h for both capsule and tablet. The mean elimination half-life of QN from the i.v. and oral dosage forms varied between 10 and 13.5 hr and were not statistically different (P > 0.05). On the contrary, the maximum plasma concentration (C(max)) and area under the curve (AUC) from capsule were comparable to those from i.v. (P > 0.05), while these values were markedly higher than values from tablet formulation (P < 0.05). The therapeutic QN plasma levels were not achieved with the tablet formulation. The absolute bioavailability (F) were 73% (C.l., 53.3 - 92.4%) and 39 % (C.I., 21.7 - 56.6%) for the capsule and tablet respectively and the difference was significant (P < 0.05). The subtherapeutic levels obtained from the tablet form used in this study may cause treatment failure during malaria and caution should be taken when predictions are made from results obtained from different formulations of QN.

  16. Absolute optical metrology : nanometers to kilometers

    NASA Technical Reports Server (NTRS)

    Dubovitsky, Serge; Lay, O. P.; Peters, R. D.; Liebe, C. C.

    2005-01-01

    We provide and overview of the developments in the field of high-accuracy absolute optical metrology with emphasis on space-based applications. Specific work on the Modulation Sideband Technology for Absolute Ranging (MSTAR) sensor is described along with novel applications of the sensor.

  17. ON A SUFFICIENT CONDITION FOR ABSOLUTE CONTINUITY.

    DTIC Science & Technology

    The formulation of a condition which yields absolute continuity when combined with continuity and bounded variation is the problem considered in the...Briefly, the formulation is achieved through a discussion which develops a proof by contradiction of a sufficiently theorem for absolute continuity which uses in its hypothesis the condition of continuity and bounded variation .

  18. Introducing the Mean Absolute Deviation "Effect" Size

    ERIC Educational Resources Information Center

    Gorard, Stephen

    2015-01-01

    This paper revisits the use of effect sizes in the analysis of experimental and similar results, and reminds readers of the relative advantages of the mean absolute deviation as a measure of variation, as opposed to the more complex standard deviation. The mean absolute deviation is easier to use and understand, and more tolerant of extreme…

  19. Monolithically integrated absolute frequency comb laser system

    SciTech Connect

    Wanke, Michael C.

    2016-07-12

    Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

  20. On the limits of using combined U-series/ESR method to date fossil teeth from two Early Pleistocene archaeological sites of the Orce area (Guadix-Baza basin, Spain)

    NASA Astrophysics Data System (ADS)

    Duval, Mathieu; Falguères, Christophe; Bahain, Jean-Jacques; Grün, Rainer; Shao, Qingfeng; Aubert, Maxime; Dolo, Jean-Michel; Agustí, Jordi; Martínez-Navarro, Bienvenido; Palmqvist, Paul; Toro-Moyano, Isidro

    2012-05-01

    The combined U-series/electron spin resonance (ESR) dating method was applied to nine teeth from two Early Pleistocene archaeological sites located in the Orce area (Guadix-Baza Basin, Southern Spain): Fuente Nueva-3 (FN-3) and Barranco León (BL). The combination of biostratigraphy and magnetostratigraphy places both sites between the Olduvai and Jaramillo subchrons (1.78-1.07 Ma). Our results highlight the difficulty of dating such old sites and point out the limits of the combined U-series/ESR dating method based on the US model. We identified several sources of uncertainties that may lead to inaccurate age estimates. Seven samples could not be dated because the dental tissues had (230Th/234U) activity ratios higher than equilibrium, indicating that uranium had probably leached from these tissues. It was however possible to calculate numerical estimates for two of the teeth, both from FN-3. One yielded a Middle Pleistocene age that seems to be strongly underestimated; the other provided an age of 1.19 ± 0.21 Ma, in agreement with data obtained from independent methods. The latter result gives encouragement that there are samples that can be used for routine dating of old sites.

  1. Accurate absolute GPS positioning through satellite clock error estimation

    NASA Astrophysics Data System (ADS)

    Han, S.-C.; Kwon, J. H.; Jekeli, C.

    2001-05-01

    An algorithm for very accurate absolute positioning through Global Positioning System (GPS) satellite clock estimation has been developed. Using International GPS Service (IGS) precise orbits and measurements, GPS clock errors were estimated at 30-s intervals. Compared to values determined by the Jet Propulsion Laboratory, the agreement was at the level of about 0.1 ns (3 cm). The clock error estimates were then applied to an absolute positioning algorithm in both static and kinematic modes. For the static case, an IGS station was selected and the coordinates were estimated every 30 s. The estimated absolute position coordinates and the known values had a mean difference of up to 18 cm with standard deviation less than 2 cm. For the kinematic case, data obtained every second from a GPS buoy were tested and the result from the absolute positioning was compared to a differential GPS (DGPS) solution. The mean differences between the coordinates estimated by the two methods are less than 40 cm and the standard deviations are less than 25 cm. It was verified that this poorer standard deviation on 1-s position results is due to the clock error interpolation from 30-s estimates with Selective Availability (SA). After SA was turned off, higher-rate clock error estimates (such as 1 s) could be obtained by a simple interpolation with negligible corruption. Therefore, the proposed absolute positioning technique can be used to within a few centimeters' precision at any rate by estimating 30-s satellite clock errors and interpolating them.

  2. Development of molecular method for sex identification in date palm (Phoenix dactylifera L.) plantlets using novel sex-linked microsatellite markers.

    PubMed

    Maryam; Jaskani, Muhammad Jafar; Awan, Faisal Saeed; Ahmad, Saeed; Khan, Iqrar A

    2016-06-01

    Microsatellite markers containing simple sequence repeats (SSRs) are a valuable tool for genetic analysis. Date palm is a dioecious and slow flowering and is very difficult to identify the gender of the trees until it reaches the reproductive age (5-10 years). A total of 12 microsatellite primers were used with 30 date palm samples, 14 parents (8 male + 6 females) and 16 progeny (developed from parents breeding) which showed that microsatellites were highly polymorphic, having a great number of alleles. A total of 124 alleles were characterized in 12 SSR loci. On average, there are 9.08 alleles per locus, with a range from 5 to 16 alleles, for primers mpdCIR15 and mpdCIR57, respectively. These primers produced 15 polymorphic loci specifically in male date palm samples and the seedlings harboring the unique fragments were further characterized as male plants. Increasingly, 38.46 % of these loci were scored as homozygous alleles while 61.53 % heterozygous allelic loci were determined. Primer mpdCIR48 produced a specific locus (250/250) in all male samples whereas the same locus was absent in female samples. Similarly, a locus of 300/310 bp reoccurred in 5 date palm male samples using marker DP-168 which indicated that these are the promising candidate marker to detect the sex in date palm seedlings at early stage. The data resulted from combination of 12 primers enabled the 16 seedling samples progeny (developed from parents breeding) of date palm cultivars to divide into two groups i.e., male and female regarding their sex expression comparative to the parents (male + female) using the principle coordinate analysis.

  3. Absolute instability of the Gaussian wake profile

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.; Aggarwal, Arun K.

    1987-01-01

    Linear parallel-flow stability theory has been used to investigate the effect of viscosity on the local absolute instability of a family of wake profiles with a Gaussian velocity distribution. The type of local instability, i.e., convective or absolute, is determined by the location of a branch-point singularity with zero group velocity of the complex dispersion relation for the instability waves. The effects of viscosity were found to be weak for values of the wake Reynolds number, based on the center-line velocity defect and the wake half-width, larger than about 400. Absolute instability occurs only for sufficiently large values of the center-line wake defect. The critical value of this parameter increases with decreasing wake Reynolds number, thereby indicating a shrinking region of absolute instability with decreasing wake Reynolds number. If backflow is not allowed, absolute instability does not occur for wake Reynolds numbers smaller than about 38.

  4. Measurements of the reactor neutron power in absolute units

    SciTech Connect

    Lebedev, G. V.

    2015-12-15

    The neutron power of the reactor of the Yenisei space nuclear power plant is measured in absolute units using the modernized method of correlation analysis during the ground-based tests of the Yenisei prototypes. Results of the experiments are given. The desired result is obtained in a series of experiments carried out at the stage of the plant preparation for tests. The acceptability of experimental data is confirmed by the results of measuring the reactor neutron power in absolute units at the nominal level by the thermal balance during the life cycle tests of the ground prototypes.

  5. Absolute Stability Analysis of a Phase Plane Controlled Spacecraft

    NASA Technical Reports Server (NTRS)

    Jang, Jiann-Woei; Plummer, Michael; Bedrossian, Nazareth; Hall, Charles; Jackson, Mark; Spanos, Pol

    2010-01-01

    Many aerospace attitude control systems utilize phase plane control schemes that include nonlinear elements such as dead zone and ideal relay. To evaluate phase plane control robustness, stability margin prediction methods must be developed. Absolute stability is extended to predict stability margins and to define an abort condition. A constrained optimization approach is also used to design flex filters for roll control. The design goal is to optimize vehicle tracking performance while maintaining adequate stability margins. Absolute stability is shown to provide satisfactory stability constraints for the optimization.

  6. Absolute distance sensing by two laser optical interferometry.

    PubMed

    Thurner, Klaus; Braun, Pierre-François; Karrai, Khaled

    2013-11-01

    We have developed a method for absolute distance sensing by two laser optical interferometry. A particularity of this technique is that a target distance is determined in absolute and is no longer limited to within an ambiguity range affecting usually multiple wavelength interferometers. We implemented the technique in a low-finesse Fabry-Pérot miniature fiber based interferometer. We used two diode lasers, both operating in the 1550 nm wavelength range. The wavelength difference is chosen to create a 25 μm long periodic beating interferometric pattern allowing a nanometer precise position measurement but limited to within an ambiguity range of 25 μm. The ambiguity is then eliminated by scanning one of the wavelengths over a small range (3.4 nm). We measured absolute distances in the sub-meter range and this with just few nanometer repeatability.

  7. Absolute Value Inequalities: High School Students' Solutions and Misconceptions

    ERIC Educational Resources Information Center

    Almog, Nava; Ilany, Bat-Sheva

    2012-01-01

    Inequalities are one of the foundational subjects in high school math curricula, but there is a lack of academic research into how students learn certain types of inequalities. This article fills part of the research gap by presenting the findings of a study that examined high school students' methods of approaching absolute value inequalities,…

  8. Mathematical Model for Absolute Magnetic Measuring Systems in Industrial Applications

    NASA Astrophysics Data System (ADS)

    Fügenschuh, Armin; Fügenschuh, Marzena; Ludszuweit, Marina; Mojsic, Aleksandar; Sokół, Joanna

    2015-09-01

    Scales for measuring systems are either based on incremental or absolute measuring methods. Incremental scales need to initialize a measurement cycle at a reference point. From there, the position is computed by counting increments of a periodic graduation. Absolute methods do not need reference points, since the position can be read directly from the scale. The positions on the complete scales are encoded using two incremental tracks with different graduation. We present a new method for absolute measuring using only one track for position encoding up to micrometre range. Instead of the common perpendicular magnetic areas, we use a pattern of trapezoidal magnetic areas, to store more complex information. For positioning, we use the magnetic field where every position is characterized by a set of values measured by a hall sensor array. We implement a method for reconstruction of absolute positions from the set of unique measured values. We compare two patterns with respect to uniqueness, accuracy, stability and robustness of positioning. We discuss how stability and robustness are influenced by different errors during the measurement in real applications and how those errors can be compensated.

  9. Analysis of standard reference materials by absolute INAA

    SciTech Connect

    Heft, R.E.; Koszykowski, R.F.

    1981-07-01

    Three standard reference materials, flyash, soil, and ASI 4340 steel, were analyzed by a method of absolute instrumental neutron activation analysis (INAA). Two different light water pool-type reactors were used to produce equivalent analytical results even though the epithermal to thermal flux ratio in one reactor was higher than that in the other by a factor of two.

  10. Infrared and Visible Absolute and Difference Spectra of Bacteriorhodopsin Photocycle Intermediates

    PubMed Central

    Hendler, Richard W.; Meuse, Curtis W.; Braiman, Mark S.; Smith, Paul D.; Kakareka, John W.

    2014-01-01

    We have used new kinetic fitting procedures to obtain IR absolute spectra for intermediates of the main bacteriorhodopsin (bR) photocycle(s). The linear algebra-based procedures of Hendler et al. (2001) J. Phys. Chem. B, 105, 3319–3228, for obtaining clean absolute visible spectra of bR photocycle intermediates, were adapted for use with IR data. This led to isolation, for the first time, of corresponding clean absolute IR spectra, including the separation of the M intermediate into its MF and MS components from parallel photocycles. This in turn permitted the computation of clean IR difference spectra between pairs of successive intermediates, allowing for the most rigorous analysis to date of changes occurring at each step of the photocycle. The statistical accuracy of the spectral calculation methods allows us to identify, with great confidence, new spectral features. One of these is a very strong differential IR band at 1650 cm−1 for the L intermediate at room temperature that is not present in analogous L spectra measured at cryogenic temperatures. This band, in one of the noisiest spectral regions, has not been identified in any previous time-resolved IR papers, although retrospectively it is apparent as one of the strongest L absorbance changes in their raw data, considered collectively. Additionally, our results are most consistent with Arg82 as the primary proton-release group (PRG), rather than a protonated water cluster or H-bonded grouping of carboxylic residues. Notably, the Arg82 deprotonation occurs exclusively in the MF pathway of the parallel cycles model of the photocycle. PMID:21929858

  11. Dating the Crucifixion

    NASA Astrophysics Data System (ADS)

    Humphreys, Colin J.; Waddington, W. G.

    1983-12-01

    The date of the Crucifixion has been debated for many years, but there has been no agreement on the year nor the day. Astronomical calculations have now been used to reconstruct the Jewish calendar in the first century AD and to date a lunar eclipse that biblical and other references suggest followed the Crucifixion. The evidence points to Friday 3 April AD 33 as the date when Jesus Christ died.

  12. Use of an intravenous microdose of 14C-labeled drug and accelerator mass spectrometry to measure absolute oral bioavailability in dogs; cross-comparison of assay methods by accelerator mass spectrometry and liquid chromatography-tandem mass spectrometry.

    PubMed

    Miyaji, Yoshihiro; Ishizuka, Tomoko; Kawai, Kenji; Hamabe, Yoshimi; Miyaoka, Teiji; Oh-hara, Toshinari; Ikeda, Toshihiko; Kurihara, Atsushi

    2009-01-01

    A technique utilizing simultaneous intravenous microdosing of (14)C-labeled drug with oral dosing of non-labeled drug for measurement of absolute bioavailability was evaluated using R-142086 in male dogs. Plasma concentrations of R-142086 were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and those of (14)C-R-142086 were measured by accelerator mass spectrometry (AMS). The absence of metabolites in the plasma and urine was confirmed by a single radioactive peak of the parent compound in the chromatogram after intravenous microdosing of (14)C-R-142086 (1.5 microg/kg). Although plasma concentrations of R-142086 determined by LC-MS/MS were approximately 20% higher than those of (14)C-R-142086 as determined by AMS, there was excellent correlation (r=0.994) between both concentrations after intravenous dosing of (14)C-R-142086 (0.3 mg/kg). The oral bioavailability of R-142086 at 1 mg/kg obtained by simultaneous intravenous microdosing of (14)C-R-142086 was 16.1%, this being slightly higher than the value (12.5%) obtained by separate intravenous dosing of R-142086 (0.3 mg/kg). In conclusion, on utilizing simultaneous intravenous microdosing of (14)C-labeled drug in conjunction with AMS analysis, absolute bioavailability could be approximately measured in dogs, but without total accuracy. Bioavailability in humans may possibly be approximately measured at an earlier stage and at a lower cost.

  13. The Absolute Gravimeter FG5 - Adjustment and Residual Data Evaluation

    NASA Astrophysics Data System (ADS)

    Orlob, M.; Braun, A.; Henton, J.; Courtier, N.; Liard, J.

    2009-05-01

    The most widely used method of direct terrestrial gravity determination is performed by using a ballistic absolute gravimeter. Today, the FG5 (Micro-g LaCoste; Lafayette, CO) is the most common free-fall absolute gravimeter. It uses the Michelson-type interferometer to determine the absolute gravity value with accuracies up to one part- per-billion of g. Furthermore, absolute gravimeter measurements can be used to assist in the validation and interpretation of temporal variations of the global gravity field, e.g. from the GRACE mission. In addition, absolute gravimetry allows for monitoring gravity changes which are caused by subsurface mass redistributions and/or vertical displacements. In this study,adjustment software was developed and applied to the raw data sets of FG5#106 and FG5#236, made available by Natural Resources Canada. Both data sets have been collected at the same time and place which leads to an intercomparison of the instruments performance. The adjustment software was validated against the official FG5 software package developed by Micro-g Lacoste. In order to identify potential environmental or instrument disturbances in the observed time series, a Lomb- Scargle periodogram analysis was employed. The absolute gravimeter FG5 is particularly sensitive to low frequencies between 0-3Hz. Hence, the focus of the analysis is to detect signals in the band of 0-100 Hz. An artificial signal was added to the measurements for demonstration purposes. Both the performance of the adjustment software and the Lomb-Scargle analysis will be discussed.

  14. Choosing a calving date

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calving date affects cost and timing of production events. Due to the polyestrous nature of beef females, producers can choose a calving date that fits their production system and geographic region. Any time an entire production system is considered, decision making becomes complex. Any calving syst...

  15. Pests of stored dates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dates are a major food crop across a large band of Africa and Eurasia, and to a lesser extent elsewhere. In most of its growing range, dates are threatened with infestation in the field by a complex of pests including nitidulid beetles and pyralid moths of the Subfamily Phycitinae. They are further ...

  16. Date Palm Germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter reviews date palm genetic resources and their conservation. Date palm (Phoenix dactylifera) is an important food crop in the Middle East and North Africa. Its center of origin and diversity most probably is the area near Iraq/Iran. From there, it spread throughout its present range...

  17. Dating Violence in Russia

    ERIC Educational Resources Information Center

    Lysova, A. V.

    2007-01-01

    The phenomenon of violence in interpersonal relationships has been little studied in Russia, and the phenomenon of violence between dating partners has not been the object of scientific interest at all. The study on which the present article is based was designed to obtain information about the violence in dating among students enrolled in…

  18. Radiocarbon dating accuracy improved

    NASA Astrophysics Data System (ADS)

    Scientists have extended the accuracy of carbon-14 (14C) dating by correlating dates older than 8,000 years with uranium-thorium dates that span from 8,000 to 30,000 years before present (ybp, present = 1950). Edouard Bard, Bruno Hamelin, Richard Fairbanks and Alan Zindler, working at Columbia University's Lamont-Doherty Geological Observatory, dated corals from reefs off Barbados using both 14C and uranium-234/thorium-230 by thermal ionization mass spectrometry techniques. They found that the two age data sets deviated in a regular way, allowing the scientists to correlate the two sets of ages. The 14C dates were consistently younger than those determined by uranium-thorium, and the discrepancy increased to about 3,500 years at 20,000 ybp.

  19. Determination of absolute internal conversion coefficients using the SAGE spectrometer

    NASA Astrophysics Data System (ADS)

    Sorri, J.; Greenlees, P. T.; Papadakis, P.; Konki, J.; Cox, D. M.; Auranen, K.; Partanen, J.; Sandzelius, M.; Pakarinen, J.; Rahkila, P.; Uusitalo, J.; Herzberg, R.-D.; Smallcombe, J.; Davies, P. J.; Barton, C. J.; Jenkins, D. G.

    2016-03-01

    A non-reference based method to determine internal conversion coefficients using the SAGE spectrometer is carried out for transitions in the nuclei of 154Sm, 152Sm and 166Yb. The Normalised-Peak-to-Gamma method is in general an efficient tool to extract internal conversion coefficients. However, in many cases the required well-known reference transitions are not available. The data analysis steps required to determine absolute internal conversion coefficients with the SAGE spectrometer are presented. In addition, several background suppression methods are introduced and an example of how ancillary detectors can be used to select specific reaction products is given. The results obtained for ground-state band E2 transitions show that the absolute internal conversion coefficients can be extracted using the methods described with a reasonable accuracy. In some cases of less intense transitions only an upper limit for the internal conversion coefficient could be given.

  20. A New Gimmick for Assigning Absolute Configuration.

    ERIC Educational Resources Information Center

    Ayorinde, F. O.

    1983-01-01

    A five-step procedure is provided to help students in making the assignment absolute configuration less bothersome. Examples for both single (2-butanol) and multi-chiral carbon (3-chloro-2-butanol) molecules are included. (JN)

  1. Magnifying absolute instruments for optically homogeneous regions

    SciTech Connect

    Tyc, Tomas

    2011-09-15

    We propose a class of magnifying absolute optical instruments with a positive isotropic refractive index. They create magnified stigmatic images, either virtual or real, of optically homogeneous three-dimensional spatial regions within geometrical optics.

  2. The Simplicity Argument and Absolute Morality

    ERIC Educational Resources Information Center

    Mijuskovic, Ben

    1975-01-01

    In this paper the author has maintained that there is a similarity of thought to be found in the writings of Cudworth, Emerson, and Husserl in his investigation of an absolute system of morality. (Author/RK)

  3. Absolute cross sections of compound nucleus reactions

    NASA Astrophysics Data System (ADS)

    Capurro, O. A.

    1993-11-01

    The program SEEF is a Fortran IV computer code for the extraction of absolute cross sections of compound nucleus reactions. When the evaporation residue is fed by its parents, only cumulative cross sections will be obtained from off-line gamma ray measurements. But, if one has the parent excitation function (experimental or calculated), this code will make it possible to determine absolute cross sections of any exit channel.

  4. Kelvin and the absolute temperature scale

    NASA Astrophysics Data System (ADS)

    Erlichson, Herman

    2001-07-01

    This paper describes the absolute temperature scale of Kelvin (William Thomson). Kelvin found that Carnot's axiom about heat being a conserved quantity had to be abandoned. Nevertheless, he found that Carnot's fundamental work on heat engines was correct. Using the concept of a Carnot engine Kelvin found that Q1/Q2 = T1/T2. Thermometers are not used to obtain absolute temperatures since they are calculated temperatures.

  5. A New Absolute Plate Motion Model for Africa

    NASA Astrophysics Data System (ADS)

    Maher, S. M.; Wessel, P.; Müller, D.; Harada, Y.

    2013-12-01

    The India-Eurasia collision, a change in relative plate motion between Australia and Antarctica, and the coeval ages of the Hawaiian Emperor Bend (HEB) and Louisville Bend of ~Chron 22-21 all provide convincing evidence of a global tectonic plate reorganization at ~50 Ma. Yet if it were a truly global event, then there should be a contemporaneous change in Africa absolute plate motion (APM) reflected by physical evidence somewhere on the Africa plate. This evidence might be visible in the Reunion-Mascarene bend, which exhibits many HEB-like features such as a large angular change close to ~50 Ma. Recently, the Reunion hotpot trail has been interpreted as a continental feature with incidental hotspot volcanism. Here we propose the alternative hypothesis that the northern portion of the chain between Saya de Malha and the Seychelles (Mascarene Plateau) formed as the Reunion hotspot was situated on the Carlsberg Ridge, contemporaneously forming the Chagos-Laccadive Ridge on the India plate. We have created a 4-stage model that explores how a simple APM model fitting the Mascarene Plateau can also satisfy the age progressions and geometry of other hotspot trails on the Africa plate. This type of model could explain the apparent bifurcation of the Tristan hotspot chain, the age reversals seen along the Walvis Ridge and the diffuse nature of the St. Helena chain. To test this hypothesis we have made a new African APM model that goes back to ~80 Ma using a modified version of the Hybrid Polygonal Finite Rotation Method. This method uses seamount chains and their associated hotspots as geometric constraints for the model, and seamount age dates to determine its motion through time. The positions of the hotspots can be moved to get the best fit for the model and to explore the possibility that the ~50 Ma bend in the Reunion-Mascarene chain reflects Africa plate motion. We will examine how well this model can predict the key features reflecting Africa plate motion and

  6. The importance and attainment of accurate absolute radiometric calibration

    NASA Technical Reports Server (NTRS)

    Slater, P. N.

    1984-01-01

    The importance of accurate absolute radiometric calibration is discussed by reference to the needs of those wishing to validate or use models describing the interaction of electromagnetic radiation with the atmosphere and earth surface features. The in-flight calibration methods used for the Landsat Thematic Mapper (TM) and the Systeme Probatoire d'Observation de la Terre, Haute Resolution visible (SPOT/HRV) systems are described and their limitations discussed. The questionable stability of in-flight absolute calibration methods suggests the use of a radiative transfer program to predict the apparent radiance, at the entrance pupil of the sensor, of a ground site of measured reflectance imaged through a well characterized atmosphere. The uncertainties of such a method are discussed.

  7. A direct way to observe absolute molecular handedness

    NASA Astrophysics Data System (ADS)

    Vager, Zeev

    2014-07-01

    We claim that the polarization of electrons tunneling through the molecular electric dipole direction uniquely determines the handedness of chiral centers. Unique labeling of chiral stereo-centers must include their handedness. The conventional method is formally known as the R, S nomenclature or the Ingold-Prelog priority (CIP) rules. It requires knowledge of the spatial absolute configuration of that center. Traditionally, experimental methods of extracting handedness go through the absolute configuration and only then would the CIP convention be applied. Here we show that a direct experimental method of determination of the natural molecular handedness by the polarization of tunneling electrons is almost always compatible with the CIP convention. By the sole use of symmetry arguments we show that the chiral molecular symmetry eliminates the need of fine structure splitting. As a consequence, the polarization of electrons tunneling through the molecular electric dipole direction uniquely determines their handedness.

  8. The Relation between the Absolute Level of Parenting and Differential Parental Treatment with Adolescent Siblings' Adjustment

    ERIC Educational Resources Information Center

    Tamrouti-Makkink, Ilse D.; Dubas, Judith Semon; Gerris, Jan R. M.; van Aken, Marcel A. G.

    2004-01-01

    Background: The present study extends existing studies on the role of differential parental treatment in explaining individual differences in adolescent problem behaviors above the absolute level of parenting and clarifies the function of gender of the child, birth rank and gender constellation of the sibling dyads. Method: The absolute level of…

  9. Date Rape Drugs

    MedlinePlus

    ... also are used to help people commit other crimes, like robbery and physical assault. They are used ... be misleading because the person who commits the crime might not be dating the victim. Rather, it ...

  10. Date Rape (For Teens)

    MedlinePlus

    ... ve been drinking. continue Protect Yourself The best defense against date rape is to try to prevent ... for help if you feel threatened. Take self-defense courses. These can build confidence and teach valuable ...

  11. Dating the Vinland Map

    ScienceCinema

    None

    2016-07-12

    Scientists from Brookhaven National Laboratory, the University of Arizona, and the Smithsonian Institution used carbon-dating technology to determine the age of a controversial parchment that might be the first-ever map of North America.

  12. Dating the Vinland Map

    SciTech Connect

    2013-01-04

    Scientists from Brookhaven National Laboratory, the University of Arizona, and the Smithsonian Institution used carbon-dating technology to determine the age of a controversial parchment that might be the first-ever map of North America.

  13. Teen Dating Violence

    MedlinePlus

    ... Violence Featured Topic: Opportunities for Action Featured Topic: Bullying Research Featured Topic: Prevent Gang Membership Featured Topic: ... and alcohol Involvement in antisocial behaviors Thoughts about suicide Additionally, youth who are victims of dating violence ...

  14. Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica.

    PubMed

    Buizert, Christo; Baggenstos, Daniel; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V; Lu, Zheng-Tian; Müller, Peter; Kuhl, Tanner; Lee, James; Severinghaus, Jeffrey P; Brook, Edward J

    2014-05-13

    We present successful (81)Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ∼350-kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The (81)Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 ± 2.5 ka. Our experimental methods and sampling strategy are validated by (i) (85)Kr and (39)Ar analyses that show the samples to be free of modern air contamination and (ii) air content measurements that show the ice did not experience gas loss. We estimate the error in the (81)Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the previous interglacial period (Marine Isotope Stage 5e, 130-115 ka before present) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites where large samples are available, greatly enhancing their scientific value as archives of old ice and meteorites. At present, ATTA (81)Kr analysis requires a 40-80-kg ice sample; as sample requirements continue to decrease, (81)Kr dating of ice cores is a future possibility.

  15. Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica

    PubMed Central

    Buizert, Christo; Baggenstos, Daniel; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V.; Lu, Zheng-Tian; Müller, Peter; Kuhl, Tanner; Lee, James; Severinghaus, Jeffrey P.; Brook, Edward J.

    2014-01-01

    We present successful 81Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ∼350-kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The 81Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 ± 2.5 ka. Our experimental methods and sampling strategy are validated by (i) 85Kr and 39Ar analyses that show the samples to be free of modern air contamination and (ii) air content measurements that show the ice did not experience gas loss. We estimate the error in the 81Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the previous interglacial period (Marine Isotope Stage 5e, 130–115 ka before present) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites where large samples are available, greatly enhancing their scientific value as archives of old ice and meteorites. At present, ATTA 81Kr analysis requires a 40–80-kg ice sample; as sample requirements continue to decrease, 81Kr dating of ice cores is a future possibility. PMID:24753606

  16. Cation-ratio dating: A new rock varnish age-determination technique

    NASA Astrophysics Data System (ADS)

    Dorn, Ronald I.

    1983-07-01

    Rock varnish coats many surfaces of geomorphic and archaeologic interest in arid lands. All varnish dating techniques are limited by the time lag between the exposure of a surface to subaerial processes and the onset of varnishing. They are valid only where manganese is not remobilized after deposition, for example, in most arid environments. The premise of a new age-determination method, cation-ratio dating, is that the ratio of the more mobile cations (e.g., K and Ca) to titanium in varnish decreases with time. Although there are many inherent assumptions and potential limitations, cation-ratio dating has been verified on relative age-sequences from a Death Valley debris cone, Negev Desert talus flatirons, and prehistoric lake levels at Searles Lake in California. Varnish cation ratios have been calibrated to independently dated surfaces in the Coso volcanic field and vicinity in California. Tentative absolute dates have been assigned to geomorphic surfaces in the Coso area. Cation ratios have been used to distinguish relative ages of archaeologic artifacts in southwestern North America and to demonstrate that varnish at the South Stoddard locality, Mojave Desert, did not form in 25 yr.

  17. Jasminum flexile flower absolute from India--a detailed comparison with three other jasmine absolutes.

    PubMed

    Braun, Norbert A; Kohlenberg, Birgit; Sim, Sherina; Meier, Manfred; Hammerschmidt, Franz-Josef

    2009-09-01

    Jasminum flexile flower absolute from the south of India and the corresponding vacuum headspace (VHS) sample of the absolute were analyzed using GC and GC-MS. Three other commercially available Indian jasmine absolutes from the species: J. sambac, J. officinale subsp. grandiflorum, and J. auriculatum and the respective VHS samples were used for comparison purposes. One hundred and twenty-one compounds were characterized in J. flexile flower absolute, with methyl linolate, benzyl salicylate, benzyl benzoate, (2E,6E)-farnesol, and benzyl acetate as the main constituents. A detailed olfactory evaluation was also performed.

  18. Absolute determination of local tropospheric OH concentrations

    NASA Technical Reports Server (NTRS)

    Armerding, Wolfgang; Comes, Franz-Josef

    1994-01-01

    Long path absorption (LPA) according to Lambert Beer's law is a method to determine absolute concentrations of trace gases such as tropospheric OH. We have developed a LPA instrument which is based on a rapid tuning of the light source which is a frequency doubled dye laser. The laser is tuned across two or three OH absorption features around 308 nm with a scanning speed of 0.07 cm(exp -1)/microsecond and a repetition rate of 1.3 kHz. This high scanning speed greatly reduces the fluctuation of the light intensity caused by the atmosphere. To obtain the required high sensitivity the laser output power is additionally made constant and stabilized by an electro-optical modulator. The present sensitivity is of the order of a few times 10(exp 5) OH per cm(exp 3) for an acquisition time of a minute and an absorption path length of only 1200 meters so that a folding of the optical path in a multireflection cell was possible leading to a lateral dimension of the cell of a few meters. This allows local measurements to be made. Tropospheric measurements have been carried out in 1991 resulting in the determination of OH diurnal variation at specific days in late summer. Comparison with model calculations have been made. Interferences are mainly due to SO2 absorption. The problem of OH self generation in the multireflection cell is of minor extent. This could be shown by using different experimental methods. The minimum-maximum signal to noise ratio is about 8 x 10(exp -4) for a single scan. Due to the small size of the absorption cell the realization of an open air laboratory is possible in which by use of an additional UV light source or by additional fluxes of trace gases the chemistry can be changed under controlled conditions allowing kinetic studies of tropospheric photochemistry to be made in open air.

  19. Evaluating melt onset date in the United States using remotely sensed passive microwave derived brightness temperature

    NASA Astrophysics Data System (ADS)

    Osborne, Douglas J.

    The timing and magnitude of spring snowmelt events impact riverine flooding and inform reservoir operations. This study evaluates the ability of the Diurnal Amplitude Variation (DAV), Frequency Difference (FD) and Polarization Ratio (PR) melt onset detection algorithms to determine melt onset dates (MOD) in the mid-latitudes of the United States. The methods are evaluated using satellite remotely sensed passive microwave observations from the Advanced Microwave Scanning Radiometer - EOS (AMSR-E) sensor and compare against in situ snow measurements from 763 Snow Telemetry (SNOTEL) and Soil Climate Analysis Network (SCAN) stations. The DAV method performs best in Alaska, predicting the MOD with a mean absolute error of 9.4 days, while the Frequency Difference and Polarization Ratio methods produce mean absolute errors of 12.5 and 11.9 days, respectively. The DAV method also clearly produced the best results in Vermont, the FD method worked best in South Dakota and the PR method performed best in Arizona. None of the study's methods are recommended for California, Minnesota, Oregon and Washington. The remaining states did not have an algorithm that worked notably better than the others and it was discovered that the methods do not work for a shallow snowpack. Tree cover was also found to have little effect on the performance of the melt onset detection methods for pixels having less than 50% tree cover.

  20. Remote ultrasound palpation for robotic interventions using absolute elastography.

    PubMed

    Schneider, Caitlin; Baghani, Ali; Rohling, Robert; Salcudean, Septimiu

    2012-01-01

    Although robotic surgery has addressed many of the challenges presented by minimally invasive surgery, haptic feedback and the lack of knowledge of tissue stiffness is an unsolved problem. This paper presents a system for finding the absolute elastic properties of tissue using a freehand ultrasound scanning technique, which utilizes the da Vinci Surgical robot and a custom 2D ultrasound transducer for intraoperative use. An external exciter creates shear waves in the tissue, and a local frequency estimation method computes the shear modulus. Results are reported for both phantom and in vivo models. This system can be extended to any 6 degree-of-freedom tracking method and any 2D transducer to provide real-time absolute elastic properties of tissue.

  1. Simultaneously improving the sensitivity and absolute accuracy of CPT magnetometer.

    PubMed

    Liang, Shang-Qing; Yang, Guo-Qing; Xu, Yun-Fei; Lin, Qiang; Liu, Zhi-Heng; Chen, Zheng-Xiang

    2014-03-24

    A new method to improve the sensitivity and absolute accuracy simultaneously for coherent population trapping (CPT) magnetometer based on the differential detection method is presented. Two modulated optical beams with orthogonal circular polarizations are applied, in one of which two magnetic resonances are excited simultaneously by modulating a 3.4GHz microwave with Larmor frequency. When a microwave frequency shift is introduced, the difference in the power transmitted through the cell in each beam shows a low noise resonance. The sensitivity of 2pT/Hz @ 10Hz is achieved. Meanwhile, the absolute accuracy of ± 0.5nT within the magnetic field ranging from 20000nT to 100000nT is realized.

  2. Absolute configuration determination using enantiomeric pairs of molecularly imprinted polymers.

    PubMed

    Meador, Danielle S; Spivak, David A

    2014-03-07

    A new method for determination of absolute configuration (AC) is demonstrated using an enantiomeric pair of molecularly imprinted polymers, referred to as "DuoMIPs". The ratio of HPLC capacity factors (k') for the analyte on each of the DuoMIPs is defined as the γ factor and can be used to determine AC when above 1.2. A mnemonic based on the complementary binding geometry of the DuoMIPs was used to aid in understanding and prediction of AC.

  3. ABSOLUTE PROPERTIES OF THE ECLIPSING BINARY STAR V335 SERPENTIS

    SciTech Connect

    Lacy, Claud H. Sandberg; Fekel, Francis C.; Claret, Antonio E-mail: fekel@evans.tsuniv.edu

    2012-08-15

    V335 Ser is now known to be an eccentric double-lined A1+A3 binary star with fairly deep (0.5 mag) partial eclipses. Previous studies of the system are improved with 7456 differential photometric observations from the URSA WebScope and 5666 from the NFO WebScope, and 67 high-resolution spectroscopic observations from the Tennessee State University 2 m automatic spectroscopic telescope. From dates of minima, the apsidal period is about 880 years. Accurate (better than 2%) masses and radii are determined from analysis of the two new light curves and the radial velocity curve. Theoretical models match the absolute properties of the stars at an age of about 380 Myr, though the age agreement for the two components is poor. Tidal theory correctly confirms that the orbit should still be eccentric, but we find that standard tidal theory is unable to match the observed asynchronous rotation rates of the components' surface layers.

  4. Absolute Distance Measurement with the MSTAR Sensor

    NASA Technical Reports Server (NTRS)

    Lay, Oliver P.; Dubovitsky, Serge; Peters, Robert; Burger, Johan; Ahn, Seh-Won; Steier, William H.; Fetterman, Harrold R.; Chang, Yian

    2003-01-01

    The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. The sensor uses a single laser in conjunction with fast phase modulators and low frequency detectors. We describe the design of the system - the principle of operation, the metrology source, beamlaunching optics, and signal processing - and show results for target distances up to 1 meter. We then demonstrate how the system can be scaled to kilometer-scale distances.

  5. Absolutely relative or relatively absolute: violations of value invariance in human decision making.

    PubMed

    Teodorescu, Andrei R; Moran, Rani; Usher, Marius

    2016-02-01

    Making decisions based on relative rather than absolute information processing is tied to choice optimality via the accumulation of evidence differences and to canonical neural processing via accumulation of evidence ratios. These theoretical frameworks predict invariance of decision latencies to absolute intensities that maintain differences and ratios, respectively. While information about the absolute values of the choice alternatives is not necessary for choosing the best alternative, it may nevertheless hold valuable information about the context of the decision. To test the sensitivity of human decision making to absolute values, we manipulated the intensities of brightness stimuli pairs while preserving either their differences or their ratios. Although asked to choose the brighter alternative relative to the other, participants responded faster to higher absolute values. Thus, our results provide empirical evidence for human sensitivity to task irrelevant absolute values indicating a hard-wired mechanism that precedes executive control. Computational investigations of several modelling architectures reveal two alternative accounts for this phenomenon, which combine absolute and relative processing. One account involves accumulation of differences with activation dependent processing noise and the other emerges from accumulation of absolute values subject to the temporal dynamics of lateral inhibition. The potential adaptive role of such choice mechanisms is discussed.

  6. Absolute Radiometric Calibration of KOMPSAT-3A

    NASA Astrophysics Data System (ADS)

    Ahn, H. Y.; Shin, D. Y.; Kim, J. S.; Seo, D. C.; Choi, C. U.

    2016-06-01

    This paper presents a vicarious radiometric calibration of the Korea Multi-Purpose Satellite-3A (KOMPSAT-3A) performed by the Korea Aerospace Research Institute (KARI) and the Pukyong National University Remote Sensing Group (PKNU RSG) in 2015.The primary stages of this study are summarized as follows: (1) A field campaign to determine radiometric calibrated target fields was undertaken in Mongolia and South Korea. Surface reflectance data obtained in the campaign were input to a radiative transfer code that predicted at-sensor radiance. Through this process, equations and parameters were derived for the KOMPSAT-3A sensor to enable the conversion of calibrated DN to physical units, such as at-sensor radiance or TOA reflectance. (2) To validate the absolute calibration coefficients for the KOMPSAT-3A sensor, we performed a radiometric validation with a comparison of KOMPSAT-3A and Landsat-8 TOA reflectance using one of the six PICS (Libya 4). Correlations between top-of-atmosphere (TOA) radiances and the spectral band responses of the KOMPSAT-3A sensors at the Zuunmod, Mongolia and Goheung, South Korea sites were significant for multispectral bands. The average difference in TOA reflectance between KOMPSAT-3A and Landsat-8 image over the Libya 4, Libya site in the red-green-blue (RGB) region was under 3%, whereas in the NIR band, the TOA reflectance of KOMPSAT-3A was lower than the that of Landsat-8 due to the difference in the band passes of two sensors. The KOMPSAT-3Aensor includes a band pass near 940 nm that can be strongly absorbed by water vapor and therefore displayed low reflectance. Toovercome this, we need to undertake a detailed analysis using rescale methods, such as the spectral bandwidth adjustment factor.

  7. Absolute length measurement using manually decided stereo correspondence for endoscopy

    NASA Astrophysics Data System (ADS)

    Sasaki, M.; Koishi, T.; Nakaguchi, T.; Tsumura, N.; Miyake, Y.

    2009-02-01

    In recent years, various kinds of endoscope have been developed and widely used to endoscopic biopsy, endoscopic operation and endoscopy. The size of the inflammatory part is important to determine a method of medical treatment. However, it is not easy to measure absolute size of inflammatory part such as ulcer, cancer and polyp from the endoscopic image. Therefore, it is required measuring the size of those part in endoscopy. In this paper, we propose a new method to measure the absolute length in a straight line between arbitrary two points based on the photogrammetry using endoscope with magnetic tracking sensor which gives camera position and angle. In this method, the stereo-corresponding points between two endoscopic images are determined by the endoscopist without any apparatus of projection and calculation to find the stereo correspondences, then the absolute length can be calculated on the basis of the photogrammetry. The evaluation experiment using a checkerboard showed that the errors of the measurements are less than 2% of the target length when the baseline is sufficiently-long.

  8. Radiocarbon Dating the Anthropocene

    NASA Astrophysics Data System (ADS)

    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.

  9. Plutonium age dating reloaded

    NASA Astrophysics Data System (ADS)

    Sturm, Monika; Richter, Stephan; Aregbe, Yetunde; Wellum, Roger; Mayer, Klaus; Prohaska, Thomas

    2014-05-01

    Although the age determination of plutonium is and has been a pillar of nuclear forensic investigations for many years, additional research in the field of plutonium age dating is still needed and leads to new insights as the present work shows: Plutonium is commonly dated with the help of the 241Pu/241Am chronometer using gamma spectrometry; in fewer cases the 240Pu/236U chronometer has been used. The age dating results of the 239Pu/235U chronometer and the 238Pu/234U chronometer are scarcely applied in addition to the 240Pu/236U chronometer, although their results can be obtained simultaneously from the same mass spectrometric experiments as the age dating result of latter. The reliability of the result can be tested when the results of different chronometers are compared. The 242Pu/238U chronometer is normally not evaluated at all due to its sensitivity to contamination with natural uranium. This apparent 'weakness' that renders the age dating results of the 242Pu/238U chronometer almost useless for nuclear forensic investigations, however turns out to be an advantage looked at from another perspective: the 242Pu/238U chronometer can be utilized as an indicator for uranium contamination of plutonium samples and even help to identify the nature of this contamination. To illustrate this the age dating results of all four Pu/U clocks mentioned above are discussed for one plutonium sample (NBS 946) that shows no signs of uranium contamination and for three additional plutonium samples. In case the 242Pu/238U chronometer results in an older 'age' than the other Pu/U chronometers, contamination with either a small amount of enriched or with natural or depleted uranium is for example possible. If the age dating result of the 239Pu/235U chronometer is also influenced the nature of the contamination can be identified; enriched uranium is in this latter case a likely cause for the missmatch of the age dating results of the Pu/U chronometers.

  10. The Realities of Date Rape.

    ERIC Educational Resources Information Center

    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…

  11. East, West, North, South: A look at a method available to prehistoric cultures to both determine cardinality and the date of the equinox

    NASA Astrophysics Data System (ADS)

    Hull, Anthony B.; Ambruster, C.; Jewell, E.

    2014-01-01

    Many prehistoric world cultures have public and sacred buildings and roads which may exhibit cardinality (alignment to the true cardinal directions) to impressive precision. Careful alignment of such buildings would seem a means to relate the ground hemisphere to the celestial hemisphere. Not all prehistoric cultures cared about true cardinality, but apparently many did. Even today, lacking surveying instruments or GPS, determination of the cardinal directions, even to ±1-2 degrees, is challenging. In this paper we examine how these directions could have been accurately determined by prehistoric peoples with attentive observation using simply a gnomon. While we will not examine here their models of the cosmos, nor why they would construct to these alignments, we do examine expected systematic and random errors in such determinations if a gnomon is used. Our models demonstrate that marking the shadow locus from a gnomon not only can inform on cardinality to remarkable precision, but also is capable of giving the date of equinox to perhaps ±1-2days

  12. Absolute distance measurement based on multiple self-mixing interferometry

    NASA Astrophysics Data System (ADS)

    Duan, Zhiwei; Yu, Yangyang; Gao, Bingkun; Jiang, Chunlei

    2017-04-01

    To improve the precision of distance measurement using laser Self-Mixing Interferometry (SMI) and compute short distance, we propose a method of Multiple Self-Mixing Interferometry (MSMI) that is modulated with a triangular wave. The principle of this method has been described in this paper. Experiments at different distances and amplitudes of modulation current are based on the proposed method. Low-priced and easily operated experimental devices are built. Experimental results show that a resolution of 2.7 mm can be achieved for absolute distance ranging from 2.2 to 23 cm.

  13. Comparative vs. Absolute Judgments of Trait Desirability

    ERIC Educational Resources Information Center

    Hofstee, Willem K. B.

    1970-01-01

    Reversals of trait desirability are studied. Terms indicating conservativw behavior appeared to be judged relatively desirable in comparative judgement, while traits indicating dynamic and expansive behavior benefited from absolute judgement. The reversal effect was shown to be a general one, i.e. reversals were not dependent upon the specific…

  14. New Techniques for Absolute Gravity Measurements.

    DTIC Science & Technology

    1983-01-07

    Hammond, J.A. (1978) Bollettino Di Geofisica Teorica ed Applicata Vol. XX. 8. Hammond, J. A., and Iliff, R. L. (1979) The AFGL absolute gravity system...International Gravimetric Bureau, No. L:I-43. 7. Hammond. J.A. (1978) Bollettino Di Geofisica Teorica ed Applicata Vol. XX. 8. Hammond, J.A., and

  15. An Absolute Electrometer for the Physics Laboratory

    ERIC Educational Resources Information Center

    Straulino, S.; Cartacci, A.

    2009-01-01

    A low-cost, easy-to-use absolute electrometer is presented: two thin metallic plates and an electronic balance, usually available in a laboratory, are used. We report on the very good performance of the device that allows precise measurements of the force acting between two charged plates. (Contains 5 footnotes, 2 tables, and 6 figures.)

  16. Stimulus Probability Effects in Absolute Identification

    ERIC Educational Resources Information Center

    Kent, Christopher; Lamberts, Koen

    2016-01-01

    This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of…

  17. Absolute Positioning Using the Global Positioning System

    DTIC Science & Technology

    1994-04-01

    Global Positioning System ( GPS ) has becom a useful tool In providing relativ survey...Includes the development of a low cost navigator for wheeled vehicles. ABSTRACT The Global Positioning System ( GPS ) has become a useful tool In providing...technique of absolute or point positioning involves the use of a single Global Positioning System ( GPS ) receiver to determine the three-dimenslonal

  18. Biodiversity of date palm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The date palm (Phoenix dactylifera) is the dominant component upon which the sustainable biophysical and socio-economic structures of the oasis ecosystem are based; a fruit tree with unique nutritional, biochemical and biophysical characteristics, a rich source of aesthetic and cultural values, and ...

  19. The Dating Game.

    ERIC Educational Resources Information Center

    Zerger, Monte J.

    1998-01-01

    Presents activities to cultivate the tendency to see special qualities in numbers that can be played on certain calendar days. Includes games on the constant of the day, Fibonacci and golden ratio dates, primes, powers, December 25, and the day of the year. (ASK)

  20. Absolute concentration measurements inside a jet plume using video digitization

    NASA Astrophysics Data System (ADS)

    Vauquelin, O.

    An experimental system based on digitized video image analysis is used to measure the local value of the concentration inside a plume. Experiments are carried out in a wind-tunnel for a smoke-seeded turbulent jet plume illuminated with a laser beam. Each test is filmed, subsequently video images are digitized and analysed in order to determine the smoke absolute concentration corresponding to each pixel gray level. This non-intrusive measurement technique is first calibrated and different laws connecting gray level to concentration are established. As a first application, concentration measurements are made inside a turbulent jet plume and compared with measurements conducted using a classic gas analysis method. We finally present and discuss the possibilities offered for the measurements of absolute concentration fluctuations.

  1. Oblique-incidence sounder measurements with absolute propagation delay timing

    SciTech Connect

    Daehler, M.

    1990-05-03

    Timing from the Global Position Satellite (GPS) system has been applied to HF oblique incidence sounder measurements to produce ionograms whose propagation delay time scale is absolutely calibrated. Such a calibration is useful for interpreting ionograms in terms of the electron density true-height profile for the ionosphere responsible for the propagation. Use of the time variations in the shape of the electron density profile, in conjunction with an HF propagation model, is expected to provide better near-term (1-24 hour) HF propagation forecasts than are available from current updating systems, which use only the MUF. Such a capability may provide the basis for HF frequency management techniques which are more efficient than current methods. Absolute timing and other techniques applicable to automatic extraction of the electron-density profile from an ionogram will be discussed.

  2. Self consistent, absolute calibration technique for photon number resolving detectors.

    PubMed

    Avella, A; Brida, G; Degiovanni, I P; Genovese, M; Gramegna, M; Lolli, L; Monticone, E; Portesi, C; Rajteri, M; Rastello, M L; Taralli, E; Traina, P; White, M

    2011-11-07

    Well characterized photon number resolving detectors are a requirement for many applications ranging from quantum information and quantum metrology to the foundations of quantum mechanics. This prompts the necessity for reliable calibration techniques at the single photon level. In this paper we propose an innovative absolute calibration technique for photon number resolving detectors, using a pulsed heralded photon source based on parametric down conversion. The technique, being absolute, does not require reference standards and is independent upon the performances of the heralding detector. The method provides the results of quantum efficiency for the heralded detector as a function of detected photon numbers. Furthermore, we prove its validity by performing the calibration of a Transition Edge Sensor based detector, a real photon number resolving detector that has recently demonstrated its effectiveness in various quantum information protocols.

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

    ERIC Educational Resources Information Center

    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…

  4. Absolute Radiation Thermometry in the NIR

    NASA Astrophysics Data System (ADS)

    Bünger, L.; Taubert, R. D.; Gutschwager, B.; Anhalt, K.; Briaudeau, S.; Sadli, M.

    2017-04-01

    A near infrared (NIR) radiation thermometer (RT) for temperature measurements in the range from 773 K up to 1235 K was characterized and calibrated in terms of the "Mise en Pratique for the definition of the Kelvin" (MeP-K) by measuring its absolute spectral radiance responsivity. Using Planck's law of thermal radiation allows the direct measurement of the thermodynamic temperature independently of any ITS-90 fixed-point. To determine the absolute spectral radiance responsivity of the radiation thermometer in the NIR spectral region, an existing PTB monochromator-based calibration setup was upgraded with a supercontinuum laser system (0.45 μm to 2.4 μm) resulting in a significantly improved signal-to-noise ratio. The RT was characterized with respect to its nonlinearity, size-of-source effect, distance effect, and the consistency of its individual temperature measuring ranges. To further improve the calibration setup, a new tool for the aperture alignment and distance measurement was developed. Furthermore, the diffraction correction as well as the impedance correction of the current-to-voltage converter is considered. The calibration scheme and the corresponding uncertainty budget of the absolute spectral responsivity are presented. A relative standard uncertainty of 0.1 % (k=1) for the absolute spectral radiance responsivity was achieved. The absolute radiometric calibration was validated at four temperature values with respect to the ITS-90 via a variable temperature heatpipe blackbody (773 K ...1235 K) and at a gold fixed-point blackbody radiator (1337.33 K).

  5. Establishing a numerical chronology for the Middle Pleistocene glaciofluvial sediment record of an eastern alpine valley (Ybbs) using luminescence dating methods

    NASA Astrophysics Data System (ADS)

    Lüthgens, Christopher; Bickel, Lukas; Lomax, Johanna; Fiebig, Markus

    2014-05-01

    In the beginning of the 20th century, Albrecht Penck & Eduard Brückner developed the concept of four large scale Quaternary alpine glaciations extending into the alpine foreland. Since then, the Northern Alpine Foreland (NAF) has played a major role in the investigation of glacial and furthermore paleo-climatic events. This study focuses on the penultimate glaciation (attributed to MIS 6 in Austrian geological maps) when vast areas of the inner Alps were glaciated. In the easternmost part of the north draining valleys of the Alps, the glaciers did not reach the foreland, but formed valley glaciers confined by the mountainous terrain. This also applies for the Ybbs valley. Samples for Optically Stimulated Luminescence (OSL) dating were taken from glaciofluvial sediments exposed in three gravel pits situated close to the present day river course. Short transport distances as well as a highly dynamic depositional environment of a glacier-fed river system enhance the chances of incomplete resetting of the OSL signal prior to deposition. In such cases, quartz usually is the mineral of choice over feldspar, especially if dose rates are low and theoretically allow gaining quartz ages even beyond 150 ka. However, analyses of the quartz OSL signal characteristics by LM-OSL experiments and by CW pulse annealing have revealed the presence of a thermally unstable medium component contributing to the bulk quartz OSL signal, which may result in age underestimation. To obtain reliable age estimates for the samples, three luminescence signals were investigated (blue stimulated quartz OSL, infrared stimulated feldspar luminescence at 50°C (IRSL) and at an elevated temperature of 225°C (pIRIR)). Based on the results from these different methodological approaches, a luminescence based chronology was established for the deposition of glaciofluvial sediments in the Ybbs valley. This allows the temporal reconstruction of the glacial processes within the Ybbs catchment area during the

  6. 76 FR 77831 - 2012 Presidential Candidate Matching Fund Submission Dates and Post Date of Ineligibility Dates...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... Submit Statements of Net Outstanding Campaign Obligations AGENCY: Federal Election Commission. ACTION: Notice of matching fund submission dates and submission dates for statements of net outstanding campaign... statements of net outstanding campaign obligations (``NOCO statement'') after their dates of...

  7. Application of the authigenic 10Be/ 9Be dating method to continental sediments: Reconstruction of the Mio-Pleistocene sedimentary sequence in the early hominid fossiliferous areas of the northern Chad Basin

    NASA Astrophysics Data System (ADS)

    Lebatard, Anne-Elisabeth; Bourlès, Didier L.; Braucher, Régis; Arnold, Maurice; Duringer, Philippe; Jolivet, Marc; Moussa, Abderamane; Deschamps, Pierre; Roquin, Claude; Carcaillet, Julien; Schuster, Mathieu; Lihoreau, Fabrice; Likius, Andossa; Mackaye, Hassan Taisso; Vignaud, Patrick; Brunet, Michel

    2010-08-01

    The concentrations of atmospheric cosmogenic 10Be normalized to the solubilized fraction of its stable isotope 9Be have been measured in the authigenic phase leached from silicated continental sediments deposited since the upper Miocene in the northern Chad Basin. This method is validated by the systematic congruence with the biochronological estimations based on the fossil mammal evolutive degree of faunal assemblages. The fifty-five authigenic 10Be/ 9Be ages obtained along 12 logs distributed along two West-East cross sections that encompass best representative Mio-Pliocene outcrops including paleontological sites show a systematic stratigraphic decrease when considering all studied sedimentary facies extending from the Pleistocene up to 8 Ma and allow performing geologic correlations otherwise impossible in the studied area. The resulting global sequence evidences and temporally specifies the succession of the main paleoenvironments that have developed in this region since the Miocene. Under the special conditions encountered in the northern Chad Basin, this study demonstrates that the authigenic 10Be/ 9Be ratio may be used as a dating tool of continental sedimentary deposits from 1 to 8 Ma. The half-life of 10Be theoretically allowing dating up to 14 Ma, it may have fundamental implications on important field research such as paleoclimatology and, through the dating of fossiliferous deposits in paleontology and paleoanthropology.

  8. Date canning: a new approach for the long time preservation of date.

    PubMed

    Homayouni, Aziz; Azizi, Aslan; Keshtiban, Ata Khodavirdivand; Amini, Amir; Eslami, Ahad

    2015-04-01

    Dramatic growth in date (Phoenix dactylifera L.) production, makes it clear to apply proper methods to preserve this nutritious fruit for a long time. Numerous methods have been used to gain this goal in recent years that can be classified into non-thermal (fumigation, ozonation, irradiation, and packaging) and thermal (heat treatment, cold storage, dehydration, jam etc.) processing methods. In this paper these methods were reviewed and novel methods for date preservation were presented.

  9. Absolute Radiometric Calibration of Narrow-Swath Imaging Sensors with Reference to Non-Coincident Wide-Swath Sensors

    NASA Technical Reports Server (NTRS)

    McCorkel, Joel; Thome, Kurtis; Lockwood, Ronald

    2012-01-01

    An inter-calibration method is developed to provide absolute radiometric calibration of narrow-swath imaging sensors with reference to non-coincident wide-swath sensors. The method predicts at-sensor radiance using non-coincident imagery from the reference sensor and knowledge of spectral reflectance of the test site. The imagery of the reference sensor is restricted to acquisitions that provide similar view and solar illumination geometry to reduce uncertainties due to directional reflectance effects. Spectral reflectance of the test site is found with a simple iterative radiative transfer method using radiance values of a well-understood wide-swath sensor and spectral shape information based on historical ground-based measurements. At-sensor radiance is calculated for the narrow-swath sensor using this spectral reflectance and atmospheric parameters that are also based on historical in situ measurements. Results of the inter-calibration method show agreement on the 2 5 percent level in most spectral regions with the vicarious calibration technique relying on coincident ground-based measurements referred to as the reflectance-based approach. While the variability of the inter-calibration method based on non-coincident image pairs is significantly larger, results are consistent with techniques relying on in situ measurements. The method is also insensitive to spectral differences between the sensors by transferring to surface spectral reflectance prior to prediction of at-sensor radiance. The utility of this inter-calibration method is made clear by its flexibility to utilize image pairings with acquisition dates differing in excess of 30 days allowing frequent absolute calibration comparisons between wide- and narrow-swath sensors.

  10. From Hubble's NGSL to Absolute Fluxes

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Lindler, Don

    2012-01-01

    Hubble's Next Generation Spectral Library (NGSL) consists of R-l000 spectra of 374 stars of assorted temperature, gravity, and metallicity. Each spectrum covers the wavelength range, 0.18-1.00 microns. The library can be viewed and/or downloaded from the website, http://archive.stsci.edu/prepds/stisngsll. Stars in the NGSL are now being used as absolute flux standards at ground-based observatories. However, the uncertainty in the absolute flux is about 2%, which does not meet the requirements of dark-energy surveys. We are therefore developing an observing procedure that should yield fluxes with uncertainties less than 1 % and will take part in an HST proposal to observe up to 15 stars using this new procedure.

  11. Consistent thermostatistics forbids negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Dunkel, Jörn; Hilbert, Stefan

    2014-01-01

    Over the past 60 years, a considerable number of theories and experiments have claimed the existence of negative absolute temperature in spin systems and ultracold quantum gases. This has led to speculation that ultracold gases may be dark-energy analogues and also suggests the feasibility of heat engines with efficiencies larger than one. Here, we prove that all previous negative temperature claims and their implications are invalid as they arise from the use of an entropy definition that is inconsistent both mathematically and thermodynamically. We show that the underlying conceptual deficiencies can be overcome if one adopts a microcanonical entropy functional originally derived by Gibbs. The resulting thermodynamic framework is self-consistent and implies that absolute temperature remains positive even for systems with a bounded spectrum. In addition, we propose a minimal quantum thermometer that can be implemented with available experimental techniques.

  12. Absolute measurement of length with nanometric resolution

    NASA Astrophysics Data System (ADS)

    Apostol, D.; Garoi, F.; Timcu, A.; Damian, V.; Logofatu, P. C.; Nascov, V.

    2005-08-01

    Laser interferometer displacement measuring transducers have a well-defined traceability route to the definition of the meter. The laser interferometer is de-facto length scale for applications in micro and nano technologies. However their physical unit -half lambda is too large for nanometric resolution. Fringe interpolation-usual technique to improve the resolution-lack of reproducibility could be avoided using the principles of absolute distance measurement. Absolute distance refers to the use of interferometric techniques for determining the position of an object without the necessity of measuring continuous displacements between points. The interference pattern as produced by the interference of two point-like coherent sources is fitted to a geometric model so as to determine the longitudinal location of the target by minimizing least square errors. The longitudinal coordinate of the target was measured with accuracy better than 1 nm, for a target position range of 0.4μm.

  13. Asteroid absolute magnitudes and slope parameters

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    1991-01-01

    A new listing of absolute magnitudes (H) and slope parameters (G) has been created and published in the Minor Planet Circulars; this same listing will appear in the 1992 Ephemerides of Minor Planets. Unlike previous listings, the values of the current list were derived from fits of data at the V band. All observations were reduced in the same fashion using, where appropriate, a single basis default value of 0.15 for the slope parameter. Distances and phase angles were computed for each observation. The data for 113 asteroids was of sufficiently high quality to permit derivation of their H and G. These improved absolute magnitudes and slope parameters will be used to deduce the most reliable bias-corrected asteroid size-frequency distribution yet made.

  14. Computer processing of spectrograms for absolute intensities.

    PubMed

    Guttman, A; Golden, J; Galbraith, H J

    1967-09-01

    A computer program was developed to process photographically recorded spectra for absolute intensity. Test and calibration films are subjected to densitometric scans that provide digitally recorded densities on magnetic tapes. The nonlinear calibration data are fitted by least-squares cubic polynomials to yield a good approximation to the monochromatic H&D curves for commonly used emulsions (2475 recording film, Royal-X, Tri-X, 4-X). Several test cases were made. Results of these cases show that the machine processed absolute intensities are accurate to within 15%o. Arbitrarily raising the sensitivity threshold by 0.1 density units above gross fog yields cubic polynomial fits to the H&D curves that are radiometrically accurate within 10%. In addition, curves of gamma vs wavelength for 2475, Tri-X, and 4-X emulsions were made. These data show slight evidence of the photographic Purkinje effect in the 2475 emulsion.

  15. An absolute measure for a key currency

    NASA Astrophysics Data System (ADS)

    Oya, Shunsuke; Aihara, Kazuyuki; Hirata, Yoshito

    It is generally considered that the US dollar and the euro are the key currencies in the world and in Europe, respectively. However, there is no absolute general measure for a key currency. Here, we investigate the 24-hour periodicity of foreign exchange markets using a recurrence plot, and define an absolute measure for a key currency based on the strength of the periodicity. Moreover, we analyze the time evolution of this measure. The results show that the credibility of the US dollar has not decreased significantly since the Lehman shock, when the Lehman Brothers bankrupted and influenced the economic markets, and has increased even relatively better than that of the euro and that of the Japanese yen.

  16. Probing absolute spin polarization at the nanoscale.

    PubMed

    Eltschka, Matthias; Jäck, Berthold; Assig, Maximilian; Kondrashov, Oleg V; Skvortsov, Mikhail A; Etzkorn, Markus; Ast, Christian R; Kern, Klaus

    2014-12-10

    Probing absolute values of spin polarization at the nanoscale offers insight into the fundamental mechanisms of spin-dependent transport. Employing the Zeeman splitting in superconducting tips (Meservey-Tedrow-Fulde effect), we introduce a novel spin-polarized scanning tunneling microscopy that combines the probing capability of the absolute values of spin polarization with precise control at the atomic scale. We utilize our novel approach to measure the locally resolved spin polarization of magnetic Co nanoislands on Cu(111). We find that the spin polarization is enhanced by 65% when increasing the width of the tunnel barrier by only 2.3 Å due to the different decay of the electron orbitals into vacuum.

  17. Comparison of amino acid racemization geochronometry with lithostratigraphy, biostratigraphy, uranium-series coral dating, and magnetostratigraphy in the Atlantic Coastal Plain of the southeastern United States

    USGS Publications Warehouse

    McCartan, L.; Owens, J.P.; Blackwelder, B. W.; Szabo, B. J.; Belknap, D.F.; Kriausakul, N.; Mitterer, R.M.; Wehmiller, J. F.

    1982-01-01

    The results of an integrated study comprising litho- and biostratigraphic investigations, uranium-series coral dating, amino acid racemization in molluscs, and paleomagnetic measurements are compared to ascertain relative and absolute ages of Pleistocene deposits of the Atlantic Coastal Plain in North and South Carolina. Four depositional events are inferred for South Carolina and two for North Carolina by all methods. The data suggest that there are four Pleistocene units containing corals that have been dated at about 100,000 yr, 200,000 yr, 450,000 yr, and over 1,000,000 yr. Some conflicts exist between the different methods regarding the correlation of the younger of these depositional events between Charleston and Myrtle Beach. Lack of good uranium-series dates for the younger material at Myrtle Beach makes the correlation with the deposits at Charleston more difficult. ?? 1982.

  18. Comparison of amino acid racemization geochronometry with lithostratigraphy, biostratigraphy, uranium-series coral dating, and magnetostratigraphy in the Atlantic Coastal Plain of the southeastern United States

    NASA Astrophysics Data System (ADS)

    McCartan, L.; Owens, J. P.; Blackwelder, B. W.; Szabo, B. J.; Belknap, D. F.; Kriausakul, N.; Mitterer, R. M.; Wehmiller, J. F.

    1982-11-01

    The results of an integrated study comprising litho- and biostratigraphic investigations, uranium-series coral dating, amino acid racemization in molluscs, and paleomagnetic measurements are compared to ascertain relative and absolute ages of Pleistocene deposits of the Atlantic Coastal Plain in North and South Carolina. Four depositional events are inferred for South Carolina and two for North Carolina by all methods. The data suggest that there are four Pleistocene units containing corals that have been dated at about 100,000 yr, 200,000 yr, 450,000 yr, and over 1,000,000 yr. Some conflicts exist between the different methods regarding the correlation of the younger of these depositional events between Charleston and Myrtle Beach. Lack of good uranium-series dates for the younger material at Myrtle Beach makes the correlation with the deposits at Charleston more difficult.

  19. Silicon Absolute X-Ray Detectors

    SciTech Connect

    Seely, John F.; Korde, Raj; Sprunck, Jacob; Medjoubi, Kadda; Hustache, Stephanie

    2010-06-23

    The responsivity of silicon photodiodes having no loss in the entrance window, measured using synchrotron radiation in the 1.75 to 60 keV range, was compared to the responsivity calculated using the silicon thickness measured using near-infrared light. The measured and calculated responsivities agree with an average difference of 1.3%. This enables their use as absolute x-ray detectors.

  20. Negative absolute temperature for mobile particles

    NASA Astrophysics Data System (ADS)

    Braun, Simon; Ronzheimer, Philipp; Schreiber, Michael; Hodgman, Sean; Bloch, Immanuel; Schneider, Ulrich

    2013-05-01

    Absolute temperature is usually bound to be strictly positive. However, negative absolute temperature states, where the occupation probability of states increases with their energy, are possible in systems with an upper energy bound. So far, such states have only been demonstrated in localized spin systems with finite, discrete spectra. We realized a negative absolute temperature state for motional degrees of freedom with ultracold bosonic 39K atoms in an optical lattice, by implementing the attractive Bose-Hubbard Hamiltonian. This new state strikingly revealed itself by a quasimomentum distribution that is peaked at maximum kinetic energy. The measured kinetic energy distribution and the extracted negative temperature indicate that the ensemble is close to degeneracy, with coherence over several lattice sites. The state is as stable as a corresponding positive temperature state: The negative temperature stabilizes the system against mean-field collapse driven by negative pressure. Negative temperatures open up new parameter regimes for cold atoms, enabling fundamentally new many-body states. Additionally, they give rise to several counterintuitive effects such as heat engines with above unity efficiency.

  1. Measurement of absolute gravity acceleration in Firenze

    NASA Astrophysics Data System (ADS)

    de Angelis, M.; Greco, F.; Pistorio, A.; Poli, N.; Prevedelli, M.; Saccorotti, G.; Sorrentino, F.; Tino, G. M.

    2011-01-01

    This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the University of Firenze (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the Newtonian law at short distances are in progress. Both experiments require an independent knowledge on the local value of g. The only available datum, pertaining to the italian zero-order gravity network, was taken more than 20 years ago at a distance of more than 60 km from the study site. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are (980 492 160.6 ± 4.0) μGal and (980 492 048.3 ± 3.0) μGal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

  2. System for absolute measurements by interferometric sensors

    NASA Astrophysics Data System (ADS)

    Norton, Douglas A.

    1993-03-01

    The most common problem of interferometric sensors is their inability to measure absolute path imbalance. Presented in this paper is a signal processing system that gives absolute, unambiguous reading of optical path difference for almost any style of interferometric sensor. Key components are a wide band (incoherent) optical source, a polychromator, and FFT electronics. Advantages include no moving parts in the signal processor, no active components at the sensor location, and the use of standard single mode fiber for sensor illumination and signal transmission. Actual absolute path imbalance of the interferometer is determined without using fringe counting or other inferential techniques. The polychromator extracts the interference information that occurs at each discrete wavelength within the spectral band of the optical source. The signal processing consists of analog and digital filtering, Fast Fourier analysis, and a peak detection and interpolation algorithm. This system was originally designed for use in a remote pressure sensing application that employed a totally passive fiber optic interferometer. A performance qualification was made using a Fabry-Perot interferometer and a commercially available laser interferometer to measure the reference displacement.

  3. Chemical composition of French mimosa absolute oil.

    PubMed

    Perriot, Rodolphe; Breme, Katharina; Meierhenrich, Uwe J; Carenini, Elise; Ferrando, Georges; Baldovini, Nicolas

    2010-02-10

    Since decades mimosa (Acacia dealbata) absolute oil has been used in the flavor and perfume industry. Today, it finds an application in over 80 perfumes, and its worldwide industrial production is estimated five tons per year. Here we report on the chemical composition of French mimosa absolute oil. Straight-chain analogues from C6 to C26 with different functional groups (hydrocarbons, esters, aldehydes, diethyl acetals, alcohols, and ketones) were identified in the volatile fraction. Most of them are long-chain molecules: (Z)-heptadec-8-ene, heptadecane, nonadecane, and palmitic acid are the most abundant, and constituents such as 2-phenethyl alcohol, methyl anisate, and ethyl palmitate are present in smaller amounts. The heavier constituents were mainly triterpenoids such as lupenone and lupeol, which were identified as two of the main components. (Z)-Heptadec-8-ene, lupenone, and lupeol were quantified by GC-MS in SIM mode using external standards and represents 6%, 20%, and 7.8% (w/w) of the absolute oil. Moreover, odorant compounds were extracted by SPME and analyzed by GC-sniffing leading to the perception of 57 odorant zones, of which 37 compounds were identified by their odorant description, mass spectrum, retention index, and injection of the reference compound.

  4. Constrained Least Absolute Deviation Neural Networks

    PubMed Central

    Wang, Zhishun; Peterson, Bradley S.

    2008-01-01

    It is well known that least absolute deviation (LAD) criterion or L1-norm used for estimation of parameters is characterized by robustness, i.e., the estimated parameters are totally resistant (insensitive) to large changes in the sampled data. This is an extremely useful feature, especially, when the sampled data are known to be contaminated by occasionally occurring outliers or by spiky noise. In our previous works, we have proposed the least absolute deviation neural network (LADNN) to solve unconstrained LAD problems. The theoretical proofs and numerical simulations have shown that the LADNN is Lyapunov-stable and it can globally converge to the exact solution to a given unconstrained LAD problem. We have also demonstrated its excellent application value in time-delay estimation. More generally, a practical LAD application problem may contain some linear constraints, such as a set of equalities and/or inequalities, which is called constrained LAD problem, whereas the unconstrained LAD can be considered as a special form of the constrained LAD. In this paper, we present a new neural network called constrained least absolute deviation neural network (CLADNN) to solve general constrained LAD problems. Theoretical proofs and numerical simulations demonstrate that the proposed CLADNN is Lyapunov stable and globally converges to the exact solution to a given constrained LAD problem, independent of initial values. The numerical simulations have also illustrated that the proposed CLADNN can be used to robustly estimate parameters for nonlinear curve fitting, which is extensively used in signal and image processing. PMID:18269958

  5. Dating Violence among College Students

    ERIC Educational Resources Information Center

    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…

  6. The study of absolute distance measurement based on the self-mixing interference in laser diode

    NASA Astrophysics Data System (ADS)

    Wang, Ting-ting; Zhang, Chuang

    2009-07-01

    In this work, an absolute distance measurement method based on the self-mixing interference is presented. The principles of the method used three-mirror cavity equivalent model are studied in this paper, and the mathematical model is given. Wavelength modulation of the laser beam is obtained by saw-tooth modulating the infection current of the laser diode. Absolute distance of the external target is determined by Fourier analysis method. The frequency of signal from PD is linearly dependent on absolute distance, but also affected by temperature and fluctuation of current source. A dual-path method which uses the reference technique for absolute distance measurement has been proposed. The theoretical analysis shows that the method can eliminate errors resulting from distance-independent variations in the setup. Accuracy and stability can be improved. Simulated results show that a resolution of +/-0.2mm can be achieved for absolute distance ranging from 250mm to 500mm. In the same measurement range, the resolution we obtained is better than other absolute distance measurement system proposed base on self-mixing interference.

  7. FINAL REPORT (MILESTONE DATE 9/30/11) FOR SUBCONTRACT NO. B594099 NUMERICAL METHODS FOR LARGE-SCALE DATA FACTORIZATION

    SciTech Connect

    De Sterck, H

    2011-10-18

    The following work has been performed by PI Hans De Sterck and graduate student Manda Winlaw for the required tasks 1-5 (as listed in the Statement of Work). Graduate student Manda Winlaw has visited LLNL January 31-March 11, 2011 and May 23-August 19, 2010, working with Van Henson and Mike O'Hara on non-negative matrix factorizations (NMF). She has investigated the dense subgraph clustering algorithm from 'Finding Dense Subgraphs for Sparse Undirected, Directed, and Bipartite Graphs' by Chen and Saad, testing this method on several term-document matrices and adapting it to cluster based on the rank of the subgraphs instead of the density. Manda Winlaw was awarded a first prize in the annual LLNL summer student poster competition for a poster on her NMF research. PI Hans De Sterck has developed a new adaptive algebraic multigrid algorithm for computing a few dominant or minimal singular triplets of sparse rectangular matrices. This work builds on adaptive algebraic multigrid methods that were further developed by the PI and collaborators (including Sanders and Henson) for Markov chains. The method also combines and extends existing multigrid algorithms for the symmetric eigenproblem. The PI has visited LLNL February 22-25, 2011, and has given a CASC seminar 'Algebraic Multigrid for the Singular Value Problem' on this work on February 23, 2011. During his visit, he has discussed this work and related topics with Van Henson, Geoffrey Sanders, Panayot Vassilevski, and others. He has tested the algorithm on PDE matrices and on a term-document matrix, with promising initial results. Manda Winlaw has also started to work, with O'Hara, on estimating probability distributions over undirected graph edges. The goal is to estimate probabilistic models from sets of undirected graph edges for the purpose of prediction, anomaly detection and support to supervised learning. Graduate student Manda Winlaw is writing a paper on the results obtained with O'Hara which will be

  8. Absolute thickness metrology with submicrometer accuracy using a low-coherence distance measuring interferometer.

    PubMed

    Zhao, Yang; Schmidt, Greg; Moore, Duncan T; Ellis, Jonathan D

    2015-09-01

    Absolute physical thickness across the sample aperture is critical in determining the index of a refraction profile from the optical path length profile for gradient index (GRIN) materials, which have a designed inhomogeneous refractive index. Motivated by this application, instrumentation was established to measure the absolute thickness of samples with nominally plane-parallel surfaces up to 50 mm thick. The current system is capable of measuring absolute thickness with 120 nm (1σ) repeatability and submicrometer expanded measurement uncertainty. Beside GRIN materials, this method is also capable of measuring other inhomogeneous and opaque materials.

  9. Absolute value equations - what can we learn from their graphical representation?

    NASA Astrophysics Data System (ADS)

    Stupel, Moshe; Ben-Chaim, David

    2014-08-01

    Understanding graphical representations of algebraic equations, particularly graphical representations of absolute value equations, significantly improves students' mathematical comprehension and ignites within them an appreciation of the beauty and aesthetics of mathematics. In this paper, we focus on absolute value equations of linear and quadratic expressions, by examining various cases, presenting different methods of solving them by graphical representation, exhibiting the advantage of using dynamic software such as GeoGebra in solving them, and illustrating some examples of interesting graphical solutions. We recommend that teachers take advantage of the rapid development in technology to help learners tangibly visualize the solutions of absolute value equations before proceeding to the analytical solutions.

  10. Vulcanism and Radiocarbon Dates

    DOE R&D Accomplishments Database

    Libby, L. M.; Libby, W. F.

    1972-10-01

    We consider whether the long term perturbation of radiocarbon dates, which is known to be approximately a sin function of period about 8000 years and amplitude of about 8% peak-to-peak, could have been caused in any major part by vulcanism. We conclude that this is not the case. On the contrary, present day volcanoes are a far less important source of inert CO{sub 2} (about 100 fold less) than is man's burning of fossil fuels which has caused the Suess dilution of about 2%. (auth)

  11. Recent documents dating: an approach using radiocarbon techniques.

    PubMed

    Zavattaro, D; Quarta, G; D'Elia, M; Calcagnile, L

    2007-04-11

    The possibility to develop an absolute technique, independent from the paper conservation conditions, to date recent paper documents (i.e. less than 50 years old) for forensics purposes is discussed. We suggest the possibility to use the curve representing the strong increase in the atmospheric radiocarbon concentration induced in the last 50 years by nuclear weapons tests as reference to date paper documents, with a resolution down to a few months. The results obtained in the analysis of two known age documents are presented together with a first order mathematical model developed in order to take into account the contributions of the different tree rings employed in the paper production.

  12. Application of LiDAR Date to Assess the Landslide Susceptibility Map Using Weights of Evidence Method - AN Example from Podhale Region (southern Poland)

    NASA Astrophysics Data System (ADS)

    Kamiński, Mirosław

    2016-06-01

    Podhale is a region in southern Poland, which is the northernmost part of the Central Carpathian Mountains. It is characterized by the presence of a large number of landslides that threaten the local infrastructure. In an article presents application of LiDAR data and geostatistical methods to assess landslides susceptibility map. Landslide inventory map were performed using LiDAR data and field work. The Weights of Evidence method was applied to assess landslides susceptibility map. Used factors for modeling: slope gradient, slope aspect, elevation, drainage density, faults density, lithology and curvature. All maps were subdivided into different classes. Then were converted to grid format in the ArcGIS 10.0. The conditional independence test was carried out to determine factors that are conditionally independent of each other with landslides. As a result, chi-square test for further GIS analysis used only five factors: slope gradient, slope aspect, elevation, drainage density and lithology. The final prediction results, it is concluded that the susceptibility map gives useful information both on present instability of the area and its possible future evolution in agreement with the morphological evolution of the area.

  13. The activity ratio of 228Th to 228Ra in bone tissue of recently deceased humans: a new dating method in forensic examinations.

    PubMed

    Zinka, Bettina; Kandlbinder, Robert; Schupfner, Robert; Haas, Gerald; Wolfbeis, Otto S; Graw, Matthias

    2012-01-01

    Reliable determination of time since death in human skeletons or single bones often is limited by methodically difficulties. Determination of the specific activity ratio of natural radionuclides, in particular of 232Th (Thorium), 228Th and 228Ra (Radium) seems to be a new appropriate method to calculate the post mortem interval. These radionuclides are incorporated by any human being, mainly from food. So with an individual's death the uptake of radionuclides ends. But the decay of 232Th produces 228Ra and 228Th due to its decay series, whereas 228Th is continuously built up in the human's bones. Thus, it can be concluded that in all deceased humans at different times after death different activity ratios of 228Th to 228Ra will develop in bone. According to this fact it should be possible to calculate time since death of an individual by first analysing the specific activities of 228Th and 228Ra in bones of deceased and then determining the 228Th/228Ra activity ratio, which can be assigned to a certain post-mortem interval.

  14. On determining absolute entropy without quantum theory or the third law of thermodynamics

    NASA Astrophysics Data System (ADS)

    Steane, Andrew M.

    2016-04-01

    We employ classical thermodynamics to gain information about absolute entropy, without recourse to statistical methods, quantum mechanics or the third law of thermodynamics. The Gibbs-Duhem equation yields various simple methods to determine the absolute entropy of a fluid. We also study the entropy of an ideal gas and the ionization of a plasma in thermal equilibrium. A single measurement of the degree of ionization can be used to determine an unknown constant in the entropy equation, and thus determine the absolute entropy of a gas. It follows from all these examples that the value of entropy at absolute zero temperature does not need to be assigned by postulate, but can be deduced empirically.

  15. Absolute flatness testing of skip-flat interferometry by matrix analysis in polar coordinates.

    PubMed

    Han, Zhi-Gang; Yin, Lu; Chen, Lei; Zhu, Ri-Hong

    2016-03-20

    A new method utilizing matrix analysis in polar coordinates has been presented for absolute testing of skip-flat interferometry. The retrieval of the absolute profile mainly includes three steps: (1) transform the wavefront maps of the two cavity measurements into data in polar coordinates; (2) retrieve the profile of the reflective flat in polar coordinates by matrix analysis; and (3) transform the profile of the reflective flat back into data in Cartesian coordinates and retrieve the profile of the sample. Simulation of synthetic surface data has been provided, showing the capability of the approach to achieve an accuracy of the order of 0.01 nm RMS. The absolute profile can be retrieved by a set of closed mathematical formulas without polynomial fitting of wavefront maps or the iterative evaluation of an error function, making the new method more efficient for absolute testing.

  16. Landsat-7 ETM+ radiometric stability and absolute calibration

    USGS Publications Warehouse

    Markham, B.L.; Barker, J.L.; Barsi, J.A.; Kaita, E.; Thome, K.J.; Helder, D.L.; Palluconi, Frank Don; Schott, J.R.; Scaramuzza, P.; ,

    2002-01-01

    Launched in April 1999, the Landsat-7 ETM+ instrument is in its fourth year of operation. The quality of the acquired calibrated imagery continues to be high, especially with respect to its three most important radiometric performance parameters: reflective band instrument stability to better than ??1%, reflective band absolute calibration to better than ??5%, and thermal band absolute calibration to better than ??0.6 K. The ETM+ instrument has been the most stable of any of the Landsat instruments, in both the reflective and thermal channels. To date, the best on-board calibration source for the reflective bands has been the Full Aperture Solar Calibrator, which has indicated changes of at most -1.8% to -2.0% (95% C.I.) change per year in the ETM+ gain (band 4). However, this change is believed to be caused by changes in the solar diffuser panel, as opposed to a change in the instrument's gain. This belief is based partially on ground observations, which bound the changes in gain in band 4 at -0.7% to +1.5%. Also, ETM+ stability is indicated by the monitoring of desert targets. These image-based results for four Saharan and Arabian sites, for a collection of 35 scenes over the three years since launch, bound the gain change at -0.7% to +0.5% in band 4. Thermal calibration from ground observations revealed an offset error of +0.31 W/m 2 sr um soon after launch. This offset was corrected within the U. S. ground processing system at EROS Data Center on 21-Dec-00, and since then, the band 6 on-board calibration has indicated changes of at most +0.02% to +0.04% (95% C.I.) per year. The latest ground observations have detected no remaining offset error with an RMS error of ??0.6 K. The stability and absolute calibration of the Landsat-7 ETM+ sensor make it an ideal candidate to be used as a reference source for radiometric cross-calibrating to other land remote sensing satellite systems.

  17. On the convective-absolute nature of river bedform instabilities

    NASA Astrophysics Data System (ADS)

    Vesipa, Riccardo; Camporeale, Carlo; Ridolfi, Luca; Chomaz, Jean Marc

    2014-12-01

    River dunes and antidunes are induced by the morphological instability of stream-sediment boundary. Such bedforms raise a number of subtle theoretical questions and are crucial for many engineering and environmental problems. Despite their importance, the absolute/convective nature of the instability has never been addressed. The present work fills this gap as we demonstrate, by the cusp map method, that dune instability is convective for all values of the physical control parameters, while the antidune instability exhibits both behaviors. These theoretical predictions explain some previous experimental and numerical observations and are important to correctly plan flume experiments, numerical simulations, paleo-hydraulic reconstructions, and river works.

  18. Lens transmission measurement for an absolute radiation thermometer

    SciTech Connect

    Hao, X.; Yuan, Z.; Lu, X.

    2013-09-11

    The lens transmission for the National Institute of Metrology of China absolute radiation thermometer is measured by a hybrid method. The results of the lens transmission measurements are 99.002% and 86.792% for filter radiometers with center wavelengths 633 nm and 900 nm, respectively. These results, after correcting for diffraction factors and the size-of-source effect when the lens is incorporated within the radiometer, can be used for measurement of thermodynamic temperature. The expanded uncertainty of the lens transmission measurement system has been evaluated. It is 1.3×10{sup −3} at 633 nm and 900 nm, respectively.

  19. Absolute cross-section normalization of magnetic neutron scattering data.

    PubMed

    Xu, Guangyong; Xu, Zhijun; Tranquada, J M

    2013-08-01

    We discuss various methods to obtain the resolution volume for neutron scattering experiments, in order to perform absolute normalization on inelastic magnetic neutron scattering data. Examples from previous experiments are given. We also try to provide clear definitions of a number of physical quantities which are commonly used to describe neutron magnetic scattering results, including the dynamic spin correlation function and the imaginary part of the dynamic susceptibility. Formulas that can be used for general purposes are provided and the advantages of the different normalization processes are discussed.

  20. Absolute cross-section normalization of magnetic neutron scattering data

    NASA Astrophysics Data System (ADS)

    Xu, Guangyong; Xu, Zhijun; Tranquada, J. M.

    2013-08-01

    We discuss various methods to obtain the resolution volume for neutron scattering experiments, in order to perform absolute normalization on inelastic magnetic neutron scattering data. Examples from previous experiments are given. We also try to provide clear definitions of a number of physical quantities which are commonly used to describe neutron magnetic scattering results, including the dynamic spin correlation function and the imaginary part of the dynamic susceptibility. Formulas that can be used for general purposes are provided and the advantages of the different normalization processes are discussed.

  1. Uranium-series dating and growth characteristics of the deep-sea scleractinian coral: Enallopsammia rostrata from the Equatorial Pacific

    NASA Astrophysics Data System (ADS)

    Houlbrèque, Fanny; McCulloch, Malcolm; Roark, Brendan; Guilderson, Tom; Meibom, Anders; Kimball, Justine; Mortimer, Graham; Cuif, Jean-Pierre; Dunbar, Robert

    2010-04-01

    The deep-sea coral, Enallopsammia rostrata, a member of the Dendrophylliidae family, is a major structure-forming species that creates massive dendroid colonies, up to 1 m wide and 0.5 m tall. Living colonies of E. rostrata have been collected using the PISCES submersibles from three locations from 480 to 788 m water depth in the Line Islands (˜160°W) in the Equatorial Pacific. We have applied to these colonies a high sensitivity, low blank technique to determine U-series ages in small quantities (70 ± 15 mg) of modern and near modern calcareous skeletons using MC-ICP-MS (Multi-collector Inductively Coupled Plasma Mass Spectrometer). The application of this method to living slow-growing colonies from a range of sites as well as the observations of axial growth patterns in thin sections of their skeletons offer the first expanded and well constrained data on longevity, growth pattern and mean growth rates in E. rostrata. Absolute dated specimens indicate life spans of colonies ranging from 209 ± 8 yrs to 605 ± 7 yrs with radial growth rates from 0.012 to 0.072 mm yr -1 and vertical extension rates from 0.6 to 1.9 mm yr -1. The linear growth rates reported here are lower than those reported for other deep-sea scleractinian corals ( Lophelia pertusa and Madrepora oculata). The U-series dating indicates that the growth ring patterns of E. rostrata are not consistent with annual periodicity emphasizing the importance of absolute radiometric dating methods to constrain growth rates. Slow accretion and extreme longevity make this species and its habitat especially vulnerable to disturbances and impacts from human activities. This dating method combined with observation of growth patterns opens up new perspectives in the field of deep-sea corals since it can provide quantitative estimates of growth rates and longevity of deep-sea corals in general.

  2. The absolute radiometric calibration of the advanced very high resolution radiometer

    NASA Technical Reports Server (NTRS)

    Slater, P. N.; Teillet, P. M.; Ding, Y.

    1988-01-01

    The need for independent, redundant absolute radiometric calibration methods is discussed with reference to the Thematic Mapper. Uncertainty requirements for absolute calibration of between 0.5 and 4 percent are defined based on the accuracy of reflectance retrievals at an agricultural site. It is shown that even very approximate atmospheric corrections can reduce the error in reflectance retrieval to 0.02 over the reflectance range 0 to 0.4.

  3. VCD to determine absolute configuration of natural product molecules: secolignans from Peperomia blanda.

    PubMed

    Felippe, Lidiane G; Batista, João M; Baldoqui, Debora C; Nascimento, Isabele R; Kato, Massuo J; He, Yanan; Nafie, Laurence A; Furlan, Maysa

    2012-06-07

    The absolute configuration and solution-state conformers of three peperomin-type secolignans isolated from Peperomia blanda (Piperaceae) are unambiguously determined by using vibrational circular dichroism (VCD) spectroscopy associated with density functional theory (DFT) calculations. Advantages of VCD over the electronic form of CD for the analysis of diastereomers are also discussed. This work extends our growing knowledge about secondary metabolites within the Piperaceae family species while providing a definitive and straightforward method to assess the absolute stereochemistry of secolignans.

  4. Clock time is absolute and universal

    NASA Astrophysics Data System (ADS)

    Shen, Xinhang

    2015-09-01

    A critical error is found in the Special Theory of Relativity (STR): mixing up the concepts of the STR abstract time of a reference frame and the displayed time of a physical clock, which leads to use the properties of the abstract time to predict time dilation on physical clocks and all other physical processes. Actually, a clock can never directly measure the abstract time, but can only record the result of a physical process during a period of the abstract time such as the number of cycles of oscillation which is the multiplication of the abstract time and the frequency of oscillation. After Lorentz Transformation, the abstract time of a reference frame expands by a factor gamma, but the frequency of a clock decreases by the same factor gamma, and the resulting multiplication i.e. the displayed time of a moving clock remains unchanged. That is, the displayed time of any physical clock is an invariant of Lorentz Transformation. The Lorentz invariance of the displayed times of clocks can further prove within the framework of STR our earth based standard physical time is absolute, universal and independent of inertial reference frames as confirmed by both the physical fact of the universal synchronization of clocks on the GPS satellites and clocks on the earth, and the theoretical existence of the absolute and universal Galilean time in STR which has proved that time dilation and space contraction are pure illusions of STR. The existence of the absolute and universal time in STR has directly denied that the reference frame dependent abstract time of STR is the physical time, and therefore, STR is wrong and all its predictions can never happen in the physical world.

  5. Absolute Radiometric Calibration of EUNIS-06

    NASA Technical Reports Server (NTRS)

    Thomas, R. J.; Rabin, D. M.; Kent, B. J.; Paustian, W.

    2007-01-01

    The Extreme-Ultraviolet Normal-Incidence Spectrometer (EUNIS) is a soundingrocket payload that obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. Shortly after its successful initial flight last year, a complete end-to-end calibration was carried out to determine the instrument's absolute radiometric response over its Longwave bandpass of 300 - 370A. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibrations of both SOHO/CDS and Hinode/EIS, as well as in three post-flight calibrations of our SERTS sounding rocket payload, the precursor to EUNIS. The unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) had been calibrated to an absolute accuracy of 7% (l-sigma) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is itself a primary radiometric source standard. Scans of the EUNIS aperture were made to determine the instrument's absolute spectral sensitivity to +- 25%, considering all sources of error, and demonstrate that EUNIS-06 was the most sensitive solar E W spectrometer yet flown. The results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted 'insensitive' line ratios. Coordinated observations were made during the EUNIS-06 flight by SOHO/CDS and EIT that will allow re-calibrations of those instruments as well. In addition, future EUNIS flights will provide similar calibration updates for TRACE, Hinode/EIS, and STEREO/SECCHI/EUVI.

  6. Brownian motion: Absolute negative particle mobility

    NASA Astrophysics Data System (ADS)

    Ros, Alexandra; Eichhorn, Ralf; Regtmeier, Jan; Duong, Thanh Tu; Reimann, Peter; Anselmetti, Dario

    2005-08-01

    Noise effects in technological applications, far from being a nuisance, can be exploited with advantage - for example, unavoidable thermal fluctuations have found application in the transport and sorting of colloidal particles and biomolecules. Here we use a microfluidic system to demonstrate a paradoxical migration mechanism in which particles always move in a direction opposite to the net acting force (`absolute negative mobility') as a result of an interplay between thermal noise, a periodic and symmetric microstructure, and a biased alternating-current electric field. This counterintuitive phenomenon could be used for bioanalytical purposes, for example in the separation and fractionation of colloids, biological molecules and cells.

  7. Arbitrary segments of absolute negative mobility

    NASA Astrophysics Data System (ADS)

    Chen, Ruyin; Nie, Linru; Chen, Chongyang; Wang, Chaojie

    2017-01-01

    In previous research work, investigators have reported only one or two segments of absolute negative mobility (ANM) in a periodic potential. In fact, many segments of ANM also occur in the system considered here. We investigate transport of an inertial particle in a gating ratchet periodic potential subjected to a constant bias force. Our numerical results show that its mean velocity can decrease with the bias force increasing, i.e. ANM phenomenon. Furthermore, the ANM can take place arbitrary segments, even up to more than thirty. Intrinsic physical mechanism and conditions for arbitrary segments of ANM to occur are discussed in detail.

  8. Absolute quantification of myocardial blood flow.

    PubMed

    Yoshinaga, Keiichiro; Manabe, Osamu; Tamaki, Nagara

    2016-07-21

    With the increasing availability of positron emission tomography (PET) myocardial perfusion imaging, the absolute quantification of myocardial blood flow (MBF) has become popular in clinical settings. Quantitative MBF provides an important additional diagnostic or prognostic information over conventional visual assessment. The success of MBF quantification using PET/computed tomography (CT) has increased the demand for this quantitative diagnostic approach to be more accessible. In this regard, MBF quantification approaches have been developed using several other diagnostic imaging modalities including single-photon emission computed tomography, CT, and cardiac magnetic resonance. This review will address the clinical aspects of PET MBF quantification and the new approaches to MBF quantification.

  9. An absolute radius scale for Saturn's rings

    NASA Technical Reports Server (NTRS)

    Nicholson, Philip D.; Cooke, Maren L.; Pelton, Emily

    1990-01-01

    Radio and stellar occultation observations of Saturn's rings made by the Voyager spacecraft are discussed. The data reveal systematic discrepancies of almost 10 km in some parts of the rings, limiting some of the investigations. A revised solution for Saturn's rotation pole has been proposed which removes the discrepancies between the stellar and radio occultation profiles. Corrections to previously published radii vary from -2 to -10 km for the radio occultation, and +5 to -6 km for the stellar occultation. An examination of spiral density waves in the outer A Ring supports that the revised absolute radii are in error by no more than 2 km.

  10. Absolute Rate Theories of Epigenetic Stability

    NASA Astrophysics Data System (ADS)

    Walczak, Aleksandra M.; Onuchic, Jose N.; Wolynes, Peter G.

    2006-03-01

    Spontaneous switching events in most characterized genetic switches are rare, resulting in extremely stable epigenetic properties. We show how simple arguments lead to theories of the rate of such events much like the absolute rate theory of chemical reactions corrected by a transmission factor. Both the probability of the rare cellular states that allow epigenetic escape, and the transmission factor, depend on the rates of DNA binding and unbinding events and on the rates of protein synthesis and degradation. Different mechanisms of escape from the stable attractors occur in the nonadiabatic, weakly adiabatic and strictly adiabatic regimes, characterized by the relative values of those input rates.

  11. Absolute rate theories of epigenetic stability

    NASA Astrophysics Data System (ADS)

    Walczak, Aleksandra M.; Onuchic, José N.; Wolynes, Peter G.

    2005-12-01

    Spontaneous switching events in most characterized genetic switches are rare, resulting in extremely stable epigenetic properties. We show how simple arguments lead to theories of the rate of such events much like the absolute rate theory of chemical reactions corrected by a transmission factor. Both the probability of the rare cellular states that allow epigenetic escape and the transmission factor depend on the rates of DNA binding and unbinding events and on the rates of protein synthesis and degradation. Different mechanisms of escape from the stable attractors occur in the nonadiabatic, weakly adiabatic, and strictly adiabatic regimes, characterized by the relative values of those input rates. rate theory | stochastic gene expression | gene switches

  12. Absolute Priority for a Vehicle in VANET

    NASA Astrophysics Data System (ADS)

    Shirani, Rostam; Hendessi, Faramarz; Montazeri, Mohammad Ali; Sheikh Zefreh, Mohammad

    In today's world, traffic jams waste hundreds of hours of our life. This causes many researchers try to resolve the problem with the idea of Intelligent Transportation System. For some applications like a travelling ambulance, it is important to reduce delay even for a second. In this paper, we propose a completely infrastructure-less approach for finding shortest path and controlling traffic light to provide absolute priority for an emergency vehicle. We use the idea of vehicular ad-hoc networking to reduce the imposed travelling time. Then, we simulate our proposed protocol and compare it with a centrally controlled traffic light system.

  13. Petroleum fingerprinting: Dating a gasoline release

    SciTech Connect

    Johnson, M.D.; Morrison, R.D.

    1996-09-01

    Dating a gasoline releases is particularly important in situations involving a contaminated gasoline service station. Often the station begins under the control of a major oil company, and as it ages and deteriorates it may be operated by a series of smaller operators. When facing a claim for contamination, often operators blame former operators. Fingerprinting is one of several successful methods used to date petroleum releases on contaminated sites. The topics covered in this article are inventory reconciliation; reverse groundwater modeling; hydrocarbon fingerprinting.

  14. Absolute Spectrophotometry of 237 Open Cluster Stars

    NASA Astrophysics Data System (ADS)

    Clampitt, L.; Burstein, D.

    1994-12-01

    We present absolute spectrophotometry of 237 stars in 7 nearby open clusters: Hyades, Pleiades, Alpha Persei, Praesepe, Coma Berenices, IC 4665, and M 39. The observations were taken using the Wampler single-channel scanner (Wampler 1966) on the Crossley 0.9m telescope at Lick Observatory from July 1973 through December 1974. 21 bandpasses spanning the spectral range 3500 Angstroms to 7780 Angstroms were observed for each star, with bandwiths ranging from 32Angstroms to 64 Angstroms. Data are standardized to the Hayes--Latham (1975) system. Our measurements are compared to filter colors on the Johnson BV, Stromgren ubvy, and Geneva U V B_1 B_2 V_1 G systems, as well as to spectrophotometry of a few stars published by Gunn, Stryker & Tinsley and in the Spectrophotometric Standards Catalog (Adelman; as distributed by the NSSDC). Both internal and external comparisons to the filter systems indicate a formal statistical accuracy per bandpass of 0.01 to 0.02 mag, with apparent larger ( ~ 0.03 mag) differences in absolute calibration between this data set and existing spectrophotometry. These data will comprise part of the spectrophotometry that will be used to calibrate the Beijing-Arizona-Taipei-Connecticut Color Survey of the Sky (see separate paper by Burstein et al. at this meeting).

  15. The absolute threshold of cone vision

    PubMed Central

    Koeing, Darran; Hofer, Heidi

    2013-01-01

    We report measurements of the absolute threshold of cone vision, which has been previously underestimated due to sub-optimal conditions or overly strict subjective response criteria. We avoided these limitations by using optimized stimuli and experimental conditions while having subjects respond within a rating scale framework. Small (1′ fwhm), brief (34 msec), monochromatic (550 nm) stimuli were foveally presented at multiple intensities in dark-adapted retina for 5 subjects. For comparison, 4 subjects underwent similar testing with rod-optimized stimuli. Cone absolute threshold, that is, the minimum light energy for which subjects were just able to detect a visual stimulus with any response criterion, was 203 ± 38 photons at the cornea, ∼0.47 log units lower than previously reported. Two-alternative forced-choice measurements in a subset of subjects yielded consistent results. Cone thresholds were less responsive to criterion changes than rod thresholds, suggesting a limit to the stimulus information recoverable from the cone mosaic in addition to the limit imposed by Poisson noise. Results were consistent with expectations for detection in the face of stimulus uncertainty. We discuss implications of these findings for modeling the first stages of human cone vision and interpreting psychophysical data acquired with adaptive optics at the spatial scale of the receptor mosaic. PMID:21270115

  16. [Estimation of absolute risk for fracture].

    PubMed

    Fujiwara, Saeko

    2009-03-01

    Osteoporosis treatment aims to prevent fractures and maintain the QOL of the elderly. However, persons at high risk of future fracture cannot be effectively identified on the basis of bone density (BMD) alone, although BMD is used as an diagnostic criterion. Therefore, the WHO recommended that absolute risk for fracture (10-year probability of fracture) for each individual be evaluated and used as an index for intervention threshold. The 10-year probability of fracture is calculated based on age, sex, BMD at the femoral neck (body mass index if BMD is not available), history of previous fractures, parental hip fracture history, smoking, steroid use, rheumatoid arthritis, secondary osteoporosis and alcohol consumption. The WHO has just announced the development of a calculation tool (FRAX: WHO Fracture Risk Assessment Tool) in February this year. Fractures could be prevented more effectively if, based on each country's medical circumstances, an absolute risk value for fracture to determine when to start medical treatment is established and persons at high risk of fracture are identified and treated accordingly.

  17. Absolute stereochemistry of altersolanol A and alterporriols.

    PubMed

    Kanamaru, Saki; Honma, Miho; Murakami, Takanori; Tsushima, Taro; Kudo, Shinji; Tanaka, Kazuaki; Nihei, Ken-Ichi; Nehira, Tatsuo; Hashimoto, Masaru

    2012-02-01

    The absolute stereochemistry of altersolanol A (1) was established by observing a positive exciton couplet in the circular dichroism (CD) spectrum of the C3,C4-O-bis(2-naphthoyl) derivative 10 and by chemical correlations with known compound 8. Before the discussion, the relative stereochemistry of 1 was confirmed by X-ray crystallographic analysis. The shielding effect at C7'-OMe group by C1-O-benzoylation established the relative stereochemical relationship between the C8-C8' axial bonding and the C1-C4/C1'-C4' polyol moieties of alterporriols E (3), an atropisomer of the C8-C8' dimer of 1. As 3 could be obtained by dimerization of 1 in vitro, the absolute configuration of its central chirality elements (C1-C4) must be identical to those of 1. Spectral comparison between the experimental and theoretical CD spectra supported the above conclusion. Axial stereochemistry of novel C4-O-deoxy dimeric derivatives, alterporriols F (4) and G (5), were also revealed by comparison of their CD spectra to those of 2 and 3.

  18. Absolute Electron Extraction Efficiency of Liquid Xenon

    NASA Astrophysics Data System (ADS)

    Kamdin, Katayun; Mizrachi, Eli; Morad, James; Sorensen, Peter

    2016-03-01

    Dual phase liquid/gas xenon time projection chambers (TPCs) currently set the world's most sensitive limits on weakly interacting massive particles (WIMPs), a favored dark matter candidate. These detectors rely on extracting electrons from liquid xenon into gaseous xenon, where they produce proportional scintillation. The proportional scintillation from the extracted electrons serves to internally amplify the WIMP signal; even a single extracted electron is detectable. Credible dark matter searches can proceed with electron extraction efficiency (EEE) lower than 100%. However, electrons systematically left at the liquid/gas boundary are a concern. Possible effects include spontaneous single or multi-electron proportional scintillation signals in the gas, or charging of the liquid/gas interface or detector materials. Understanding EEE is consequently a serious concern for this class of rare event search detectors. Previous EEE measurements have mostly been relative, not absolute, assuming efficiency plateaus at 100%. I will present an absolute EEE measurement with a small liquid/gas xenon TPC test bed located at Lawrence Berkeley National Laboratory.

  19. Swarm's Absolute Scalar Magnetometers Burst Mode Results

    NASA Astrophysics Data System (ADS)

    Coisson, P.; Vigneron, P.; Hulot, G.; Crespo Grau, R.; Brocco, L.; Lalanne, X.; Sirol, O.; Leger, J. M.; Jager, T.; Bertrand, F.; Boness, A.; Fratter, I.

    2014-12-01

    Each of the three Swarm satellites embarks an Absolute Scalar Magnetometer (ASM) to provide absolute scalar measurements of the magnetic field with high accuracy and stability. Nominal data acquisition of these ASMs is 1 Hz. But they can also run in a so-called "burst mode" and provide data at 250 Hz. During the commissioning phase of the mission, seven burst mode acquisition campaigns have been run simultaneously for all satellites, obtaining a total of ten days of burs-mode data. These campaigns allowed the identification of issues related to the operations of the piezo-electric motor and the heaters connected to the ASM, that do not impact the nominal 1 Hz scalar data. We analyze the burst mode data to identify high frequency geomagnetic signals, focusing the analysis in two regions: the low latitudes, where we seek signatures of ionospheric irregularities, and the high latitudes, to identify high frequency signals related to polar region currents. Since these campaigns have been conducted during the initial months of the mission, the three satellites where still close to each other, allowing to analyze the spatial coherency of the signals. Wavelet analysis have revealed 31 Hz signals appearing in the night-side in the equatorial region.

  20. Extracting infrared absolute reflectance from relative reflectance measurements.

    PubMed

    Berets, Susan L; Milosevic, Milan

    2012-06-01

    Absolute reflectance measurements are valuable to the optics industry for development of new materials and optical coatings. Yet, absolute reflectance measurements are notoriously difficult to make. In this paper, we investigate the feasibility of extracting the absolute reflectance from a relative reflectance measurement using a reference material with known refractive index.

  1. A Conceptual Approach to Absolute Value Equations and Inequalities

    ERIC Educational Resources Information Center

    Ellis, Mark W.; Bryson, Janet L.

    2011-01-01

    The absolute value learning objective in high school mathematics requires students to solve far more complex absolute value equations and inequalities. When absolute value problems become more complex, students often do not have sufficient conceptual understanding to make any sense of what is happening mathematically. The authors suggest that the…

  2. Music Technology in the Preschool? Absolutely!

    ERIC Educational Resources Information Center

    Nardo, Rachel

    2008-01-01

    Most music educators are unaware that one of the earliest known electronic music keyboards for children dates back to 1952. It was unsophisticated in appearance, but much like the inventions of today, the mid-century electronic musical toy piqued the interest of children, and they begged their parents to buy it for them. The invention was named…

  3. Violence in Adolescent Dating Relationships

    ERIC Educational Resources Information Center

    Jouriles, Ernest N.; Platt, Cora; McDonald, Renee

    2009-01-01

    Beginning with a definition of dating and dating violence among adolescents, this article explores the factors which impact such violence. It concludes with a review of two school-based prevention/intervention programs (Safe Dates and The Youth Relationships Project). (Contains 1 table.)

  4. Sex Role and Dating Orientation.

    ERIC Educational Resources Information Center

    McCabe, M. P.; Collins, J. K.

    1979-01-01

    Male and female subjects from three age groups completed questionnaires on sex roles and dating orientations. Males approached dating from both a psychoaffectional and psychobiological orientation, while females approached it from a psychoaffectional orientation. Significant differences were found in dating attitudes between male and female…

  5. Standardization of the cumulative absolute velocity. Final report

    SciTech Connect

    O`Hara, T.F.; Jacobson, J.P.

    1991-12-01

    EPRI NP-5930, ``A Criterion for Determining Exceedance of the Operating Basis Earthquake,`` was published in July 1988. As defined in that report, the Operating Basis Earthquake (OBE) is exceeded when both a response spectrum parameter and a second damage parameter, referred to as the Cumulative Absolute Velocity (CAV), are exceeded. In the review process of the above report, it was noted that the calculation of CAV could be confounded by time history records of long duration containing low (nondamaging) acceleration. Therefore, it is necessary to standardize the method of calculating CAV to account for record length. This standardized methodology allows consistent comparisons between future CAV calculations and the adjusted CAV threshold value based upon applying the standardized methodology to the data set presented in EPRI NP-5930. The recommended method to standardize the CAV calculation is to window its calculation on a second-by-second basis for a given time history. If the absolute acceleration exceeds 0.025g at any time during each one second interval, the earthquake records used in EPRI NP-5930 have been reanalyzed and the adjusted threshold of damage for CAV was found to be 0.16g-set.

  6. Absolute Binding Energies of Core Levels in Solids from First Principles

    NASA Astrophysics Data System (ADS)

    Ozaki, Taisuke; Lee, Chi-Cheng

    2017-01-01

    A general method is presented to calculate absolute binding energies of core levels in metals and insulators, based on a penalty functional and an exact Coulomb cutoff method in the framework of density functional theory. The spurious interaction of core holes between supercells is avoided by the exact Coulomb cutoff method, while the variational penalty functional enables us to treat multiple splittings due to chemical shift, spin-orbit coupling, and exchange interaction on equal footing, both of which are not accessible by previous methods. It is demonstrated that the absolute binding energies of core levels for both metals and insulators are calculated by the proposed method in a mean absolute (relative) error of 0.4 eV (0.16%) for eight cases compared to experimental values measured with x-ray photoemission spectroscopy within a generalized gradient approximation to the exchange-correlation functional.

  7. Absolute paleointensity from Hawaiian lavas younger than 35 ka

    USGS Publications Warehouse

    Valet, J.-P.; Tric, E.; Herrero-Bervera, E.; Meynadier, L.; Lockwood, J.P.

    1998-01-01

    Paleointensity studies have been conducted in air and in argon atmosphere on nine lava flows with radiocarbon ages distributed between 3.3 and 28.2 ka from the Mauna Loa volcano in the big island of Hawaii. Determinations of paleointensity obtained at eight sites depict the same overall pattern as the previous results for the same period in Hawaii, although the overall average field intensity appears to be lower. Since the present results were determined at higher temperatures than in the previous studies, this discrepancy raises questions regarding the selection of low versus high-temperature segments that are usually made for absolute paleointensity. The virtual dipole moments are similar to those displayed by the worldwide data set obtained from dated lava flows. When averaged within finite time intervals, the worldwide values match nicely the variations of the Sint-200 synthetic record of relative paleointensity and confirm the overall decrease of the dipole field intensity during most of this period. The convergence between the existing records at Hawaii and the rest of the world does not favour the presence of persistent strong non-dipole components beneath Hawaii for this period.

  8. Fine structure of the age-chromospheric activity relation in solar-type stars. I. The Ca II infrared triplet: Absolute flux calibration

    NASA Astrophysics Data System (ADS)

    Lorenzo-Oliveira, D.; Porto de Mello, G. F.; Dutra-Ferreira, L.; Ribas, I.

    2016-10-01

    Context. Strong spectral lines are useful indicators of stellar chromospheric activity. They are physically linked to the convection efficiency, differential rotation, and angular momentum evolution and are a potential indicator of age. However, for ages > 2 Gyr, the age-activity relationship remains poorly constrained thus hampering its full application. Aims: The Ca II infrared triplet (IRT lines, λλ 8498, 8542, and 8662) has been poorly studied compared to classical chromospheric indicators. We report in this paper absolute chromospheric fluxes in the three Ca II IRT lines, based on a new calibration tied to up-to-date model atmospheres. Methods: We obtain the Ca II IRT absolute fluxes for 113 FGK stars from high signal-to-noise ratio (S/N) and high-resolution spectra covering an extensive domain of chromospheric activity levels. We perform an absolute continuum flux calibration for the Ca II IRT lines anchored in atmospheric models calculated as an explicit function of effective temperatures (Teff), metallicity ([Fe/H]), and gravities (log g) avoiding the degeneracy usually present in photometric continuum calibrations based solely on color indices. Results: The internal uncertainties achieved for continuum absolute flux calculations are ≈2% of the solar chromospheric flux, one order of magnitude lower than for photometric calibrations. Using Monte Carlo simulations, we gauge the impact of observational errors on the final chromospheric fluxes due to the absolute continuum flux calibration and find that Teffuncertainties are properly mitigated by the photospheric correction leaving [Fe/H] as the dominating factor in the chromospheric flux uncertainty. Conclusions: Across the FGK spectral types, the Ca II IRT lines are sensitive to chromospheric activity. The reduced internal uncertainties reported here enable us to build a new chromospheric absolute flux scale and explore the age-activity relation from the active regime down to very low activity levels and

  9. Use of Absolute and Comparative Performance Feedback in Absolute and Comparative Judgments and Decisions

    ERIC Educational Resources Information Center

    Moore, Don A.; Klein, William M. P.

    2008-01-01

    Which matters more--beliefs about absolute ability or ability relative to others? This study set out to compare the effects of such beliefs on satisfaction with performance, self-evaluations, and bets on future performance. In Experiment 1, undergraduate participants were told they had answered 20% correct, 80% correct, or were not given their…

  10. Obsidian Hydration Dating in the Undergraduate Curriculum.

    ERIC Educational Resources Information Center

    Manche, Emanuel P.; Lakatos, Stephen

    1986-01-01

    Provides an overview of obsidian hydration dating for the instructor by presenting: (1) principles of the method; (2) procedures; (3) applications; and (4) limitations. The theory of the method and one or more laboratory exercises can be easily introduced into the undergraduate geology curriculum. (JN)

  11. Reduction of date microbial load with ozone

    PubMed Central

    Farajzadeh, Davood; Qorbanpoor, Ali; Rafati, Hasan; Isfeedvajani, Mohsen Saberi

    2013-01-01

    Background: Date is one of the foodstuffs that are produced in tropical areas and used worldwide. Conventionally, methyl bromide and phosphine are used for date disinfection. The toxic side effects of these usual disinfectants have led food scientists to consider safer agents such as ozone for disinfection, because food safety is a top priority. The present study was performed to investigate the possibility of replacing common conventional disinfectants with ozone for date disinfection and microbial load reduction. Materials and Methods: In this experimental study, date samples were ozonized for 3 and 5 hours with 5 and 10 g/h concentrations and packed. Ozonized samples were divided into two groups and kept in an incubator which was maintained at 25°C and 40°C for 9 months. During this period, every 3 month, microbial load (bacteria, mold, and yeast) were examined in ozonized and non-ozonized samples. Results: This study showed that ozonization with 5 g/h for 3 hours, 5 g/h for 5 hours, 10 g/h for 3 hours, and 10 g/h for 5 hours leads to about 25%, 25%, 53%, and 46% reduction in date mold and yeast load and about 6%, 9%, 76%, and 74.7% reduction in date bacterial load at baseline phase, respectively. Appropriate concentration and duration of ozonization for microbial load reduction were 10 g/h and 3 hours. Conclusion: Date ozonization is an appropriate method for microbial load reduction and leads to an increase in the shelf life of dates. PMID:24124432

  12. Direct Dating of Hominids Remains In Eurasia

    NASA Astrophysics Data System (ADS)

    Yokoyama, Y.; Falguères, C.

    When archaeological sites are associated with human remains, it is relevant to be able to date those valuable remains for different reasons. The main one is that it avoids the stratigraphical problems which can be due to intrusive burials in the sequence. The other reason consists in the fact that human bones may be encountered out of established stratigraphical context. On the other hand, the majority of dating methods currently used are destructive and can not be applied on these precious samples particularly when they are older than 40,000 years and can not be dated by radiocarbon. Since several years, we have developped a completely non-destructive method which consists in the measurement of human remains using the gamma -ray spectrometry. This technique has been used recently by other laboratories. We present here two important cases for the knowledge of human evolution in Eurasia. The first example is Qafzeh site in Israel where many human skeletons have been unearthed from burials associated with fauna and lithic artefacts. This site has been dated by several independent radiometric methods. So, it was possible to compare our gamma results with the other results yielded by the different methods. The second case concerns the most evolved Homo erectus found in Java, Indonesia, at Ngandong site, close to the Solo river. A recent debate has been focused on the age of these fossils and their direct dating is of outmost importance for the knowledge of settlement of Modern Humans in South-East Asia.

  13. Absolute nonlocality via distributed computing without communication

    NASA Astrophysics Data System (ADS)

    Czekaj, Ł.; Pawłowski, M.; Vértesi, T.; Grudka, A.; Horodecki, M.; Horodecki, R.

    2015-09-01

    Understanding the role that quantum entanglement plays as a resource in various information processing tasks is one of the crucial goals of quantum information theory. Here we propose an alternative perspective for studying quantum entanglement: distributed computation of functions without communication between nodes. To formalize this approach, we propose identity games. Surprisingly, despite no signaling, we obtain that nonlocal quantum strategies beat classical ones in terms of winning probability for identity games originating from certain bipartite and multipartite functions. Moreover we show that, for a majority of functions, access to general nonsignaling resources boosts success probability two times in comparison to classical ones for a number of large enough outputs. Because there are no constraints on the inputs and no processing of the outputs in the identity games, they detect very strong types of correlations: absolute nonlocality.

  14. Determining Absolute Zero Using a Tuning Fork

    NASA Astrophysics Data System (ADS)

    Goldader, Jeffrey D.

    2008-04-01

    The Celsius and Kelvin temperature scales, we tell our students, are related. We explain that a change in temperature of 1°C corresponds to a change of 1 Kelvin and that atoms and molecules have zero kinetic energy at zero Kelvin, -273°C. In this paper, we will show how students can derive the relationship between the Celsius and Kelvin temperature scales using a simple, well-known physics experiment. By making multiple measurements of the speed of sound at different temperatures, using the classic physics experiment of determining the speed of sound with a tuning fork and variable-length tube, they can determine the temperature at which the speed of sound is zero—absolute zero.

  15. Micron Accurate Absolute Ranging System: Range Extension

    NASA Technical Reports Server (NTRS)

    Smalley, Larry L.; Smith, Kely L.

    1999-01-01

    The purpose of this research is to investigate Fresnel diffraction as a means of obtaining absolute distance measurements with micron or greater accuracy. It is believed that such a system would prove useful to the Next Generation Space Telescope (NGST) as a non-intrusive, non-contact measuring system for use with secondary concentrator station-keeping systems. The present research attempts to validate past experiments and develop ways to apply the phenomena of Fresnel diffraction to micron accurate measurement. This report discusses past research on the phenomena, and the basis of the use Fresnel diffraction distance metrology. The apparatus used in the recent investigations, experimental procedures used, preliminary results are discussed in detail. Continued research and equipment requirements on the extension of the effective range of the Fresnel diffraction systems is also described.

  16. Absolute measurements of fast neutrons using yttrium.

    PubMed

    Roshan, M V; Springham, S V; Rawat, R S; Lee, P; Krishnan, M

    2010-08-01

    Yttrium is presented as an absolute neutron detector for pulsed neutron sources. It has high sensitivity for detecting fast neutrons. Yttrium has the property of generating a monoenergetic secondary radiation in the form of a 909 keV gamma-ray caused by inelastic neutron interaction. It was calibrated numerically using MCNPX and does not need periodic recalibration. The total yttrium efficiency for detecting 2.45 MeV neutrons was determined to be f(n) approximately 4.1x10(-4) with an uncertainty of about 0.27%. The yttrium detector was employed in the NX2 plasma focus experiments and showed the neutron yield of the order of 10(8) neutrons per discharge.

  17. Measured and modelled absolute gravity in Greenland

    NASA Astrophysics Data System (ADS)

    Nielsen, E.; Forsberg, R.; Strykowski, G.

    2012-12-01

    Present day changes in the ice volume in glaciated areas like Greenland will change the load on the Earth and to this change the lithosphere will respond elastically. The Earth also responds to changes in the ice volume over a millennial time scale. This response is due to the viscous properties of the mantle and is known as Glaical Isostatic Adjustment (GIA). Both signals are present in GPS and absolute gravity (AG) measurements and they will give an uncertainty in mass balance estimates calculated from these data types. It is possible to separate the two signals if both gravity and Global Positioning System (GPS) time series are available. DTU Space acquired an A10 absolute gravimeter in 2008. One purpose of this instrument is to establish AG time series in Greenland and the first measurements were conducted in 2009. Since then are 18 different Greenland GPS Network (GNET) stations visited and six of these are visited more then once. The gravity signal consists of three signals; the elastic signal, the viscous signal and the direct attraction from the ice masses. All of these signals can be modelled using various techniques. The viscous signal is modelled by solving the Sea Level Equation with an appropriate ice history and Earth model. The free code SELEN is used for this. The elastic signal is modelled as a convolution of the elastic Greens function for gravity and a model of present day ice mass changes. The direct attraction is the same as the Newtonian attraction and is calculated as this. Here we will present the preliminary results of the AG measurements in Greenland. We will also present modelled estimates of the direct attraction, the elastic and the viscous signals.

  18. Topology, divergence dates, and macroevolutionary inferences vary between different tip-dating approaches applied to fossil theropods (Dinosauria).

    PubMed

    Bapst, D W; Wright, A M; Matzke, N J; Lloyd, G T

    2016-07-01

    Dated phylogenies of fossil taxa allow palaeobiologists to estimate the timing of major divergences and placement of extinct lineages, and to test macroevolutionary hypotheses. Recently developed Bayesian 'tip-dating' methods simultaneously infer and date the branching relationships among fossil taxa, and infer putative ancestral relationships. Using a previously published dataset for extinct theropod dinosaurs, we contrast the dated relationships inferred by several tip-dating approaches and evaluate potential downstream effects on phylogenetic comparative methods. We also compare tip-dating analyses to maximum-parsimony trees time-scaled via alternative a posteriori approaches including via the probabilistic cal3 method. Among tip-dating analyses, we find opposing but strongly supported relationships, despite similarity in inferred ancestors. Overall, tip-dating methods infer divergence dates often millions (or tens of millions) of years older than the earliest stratigraphic appearance of that clade. Model-comparison analyses of the pattern of body-size evolution found that the support for evolutionary mode can vary across and between tree samples from cal3 and tip-dating approaches. These differences suggest that model and software choice in dating analyses can have a substantial impact on the dated phylogenies obtained and broader evolutionary inferences.

  19. Relative Dating Via Fractures

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    This VIS image of the eastern part of the Tharsis region illustrates how fractures can be used in relative dating of a surface. The fractured materials on the right side of the image are embayed by younger volcanic flows originating to the west of the image. Note how the younger flows cover the ends of the fractures, and are not at all fractured themselves.

    Image information: VIS instrument. Latitude 43.2, Longitude 269.4 East (90.6 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  20. Radioisotope Dating with Accelerators.

    ERIC Educational Resources Information Center

    Muller, Richard A.

    1979-01-01

    Explains a new method of detecting radioactive isotopes by counting their accelerated ions rather than the atoms that decay during the counting period. This method increases the sensitivity by several orders of magnitude, and allows one to find the ages of much older and smaller samples. (GA)

  1. Absolute Temperature Monitoring Using RF Radiometry in the MRI Scanner

    PubMed Central

    El-Sharkawy, AbdEl-Monem M.; Sotiriadis, Paul P.; Bottomley, Paul A.; Atalar, Ergin

    2007-01-01

    Temperature detection using microwave radiometry has proven value for noninvasively measuring the absolute temperature of tissues inside the body. However, current clinical radiometers operate in the gigahertz range, which limits their depth of penetration. We have designed and built a noninvasive radiometer which operates at radio frequencies (64 MHz) with ∼100-kHz bandwidth, using an external RF loop coil as a thermal detector. The core of the radiometer is an accurate impedance measurement and automatic matching circuit of 0.05 Ω accuracy to compensate for any load variations. The radiometer permits temperature measurements with accuracy of ±0.1°K, over a tested physiological range of 28° C–40° C in saline phantoms whose electric properties match those of tissue. Because 1.5 T magnetic resonance imaging (MRI) scanners also operate at 64 MHz, we demonstrate the feasibility of integrating our radiometer with an MRI scanner to monitor RF power deposition and temperature dosimetry, obtaining coarse, spatially resolved, absolute thermal maps in the physiological range. We conclude that RF radiometry offers promise as a direct, noninvasive method of monitoring tissue heating during MRI studies and thereby providing an independent means of verifying patient-safe operation. Other potential applications include titration of hyper- and hypo-therapies. PMID:18026562

  2. Automatic section thickness determination using an absolute gradient focus function.

    PubMed

    Elozory, D T; Kramer, K A; Chaudhuri, B; Bonam, O P; Goldgof, D B; Hall, L O; Mouton, P R

    2012-12-01

    Quantitative analysis of microstructures using computerized stereology systems is an essential tool in many disciplines of bioscience research. Section thickness determination in current nonautomated approaches requires manual location of upper and lower surfaces of tissue sections. In contrast to conventional autofocus functions that locate the optimally focused optical plane using the global maximum on a focus curve, this study identified by two sharp 'knees' on the focus curve as the transition from unfocused to focused optical planes. Analysis of 14 grey-scale focus functions showed, the thresholded absolute gradient function, was best for finding detectable bends that closely correspond to the bounding optical planes at the upper and lower tissue surfaces. Modifications to this function generated four novel functions that outperformed the original. The 'modified absolute gradient count' function outperformed all others with an average error of 0.56 μm on a test set of images similar to the training set; and, an average error of 0.39 μm on a test set comprised of images captured from a different case, that is, different staining methods on a different brain region from a different subject rat. We describe a novel algorithm that allows for automatic section thickness determination based on just out-of-focus planes, a prerequisite for fully automatic computerized stereology.

  3. Simulation of absolute amplitudes of ultrasound signals using equivalent circuits.

    PubMed

    Johansson, Jonny; Martinsson, Pär-Erik; Delsing, Jerker

    2007-10-01

    Equivalent circuits for piezoelectric devices and ultrasonic transmission media can be used to cosimulate electronics and ultrasound parts in simulators originally intended for electronics. To achieve efficient system-level optimization, it is important to simulate correct, absolute amplitude of the ultrasound signal in the system, as this determines the requirements on the electronics regarding dynamic range, circuit noise, and power consumption. This paper presents methods to achieve correct, absolute amplitude of an ultrasound signal in a simulation of a pulse-echo system using equivalent circuits. This is achieved by taking into consideration loss due to diffraction and the effect of the cable that connects the electronics and the piezoelectric transducer. The conductive loss in the transmission line that models the propagation media of the ultrasound pulse is used to model the loss due to diffraction. Results show that the simulated amplitude of the echo follows measured values well in both near and far fields, with an offset of about 10%. The use of a coaxial cable introduces inductance and capacitance that affect the amplitude of a received echo. Amplitude variations of 60% were observed when the cable length was varied between 0.07 m and 2.3 m, with simulations predicting similar variations. The high precision in the achieved results show that electronic design and system optimization can rely on system simulations alone. This will simplify the development of integrated electronics aimed at ultrasound systems.

  4. Utilizing a reference material for assessing absolute tumor mechanical properties in modality independent elastography

    NASA Astrophysics Data System (ADS)

    Kim, Dong Kyu; Weis, Jared A.; Yankeelov, Thomas E.; Miga, Michael I.

    2014-03-01

    There is currently no reliable method for early characterization of breast cancer response to neoadjuvant chemotherapy (NAC) [1,2]. Given that disruption of normal structural architecture occurs in cancer-bearing tissue, we hypothesize that further structural changes occur in response to NAC. Consequently, we are investigating the use of modalityindependent elastography (MIE) [3-8] as a method for monitoring mechanical integrity to predict long term outcomes in NAC. Recently, we have utilized a Demons non-rigid image registration method that allows 3D elasticity reconstruction in abnormal tissue geometries, making it particularly amenable to the evaluation of breast cancer mechanical properties. While past work has reflected relative elasticity contrast ratios [3], this study improves upon that work by utilizing a known stiffness reference material within the reconstruction framework such that a stiffness map becomes an absolute measure. To test, a polyvinyl alcohol (PVA) cryogel phantom and a silicone rubber mock mouse tumor phantom were constructed with varying mechanical stiffness. Results showed that an absolute measure of stiffness could be obtained based on a reference value. This reference technique demonstrates the ability to generate accurate measurements of absolute stiffness to characterize response to NAC. These results support that `referenced MIE' has the potential to reliably differentiate absolute tumor stiffness with significant contrast from that of surrounding tissue. The use of referenced MIE to obtain absolute quantification of biomarkers is also translatable across length scales such that the characterization method is mechanics-consistent at the small animal and human application.

  5. Regional absolute conductivity reconstruction using projected current density in MREIT.

    PubMed

    Sajib, Saurav Z K; Kim, Hyung Joong; Kwon, Oh In; Woo, Eung Je

    2012-09-21

    Magnetic resonance electrical impedance tomography (MREIT) is a non-invasive technique for imaging the internal conductivity distribution in tissue within an MRI scanner, utilizing the magnetic flux density, which is introduced when a current is injected into the tissue from external electrodes. This magnetic flux alters the MRI signal, so that appropriate reconstruction can provide a map of the additional z-component of the magnetic field (B(z)) as well as the internal current density distribution that created it. To extract the internal electrical properties of the subject, including the conductivity and/or the current density distribution, MREIT techniques use the relationship between the external injection current and the z-component of the magnetic flux density B = (B(x), B(y), B(z)). The tissue studied typically contains defective regions, regions with a low MRI signal and/or low MRI signal-to-noise-ratio, due to the low density of nuclear magnetic resonance spins, short T(2) or T*(2) relaxation times, as well as regions with very low electrical conductivity, through which very little current traverses. These defective regions provide noisy B(z) data, which can severely degrade the overall reconstructed conductivity distribution. Injecting two independent currents through surface electrodes, this paper proposes a new direct method to reconstruct a regional absolute isotropic conductivity distribution in a region of interest (ROI) while avoiding the defective regions. First, the proposed method reconstructs the contrast of conductivity using the transversal J-substitution algorithm, which blocks the propagation of severe accumulated noise from the defective region to the ROI. Second, the proposed method reconstructs the regional projected current density using the relationships between the internal current density, which stems from a current injection on the surface, and the measured B(z) data. Combining the contrast conductivity distribution in the entire

  6. Computational Age Dating of Special Nuclear Materials

    SciTech Connect

    None, None

    2012-06-30

    This slide-show presented an overview of the Constrained Progressive Reversal (CPR) method for computing decays, age dating, and spoof detecting. The CPR method is: Capable of temporal profiling a SNM sample; Precise (compared with known decay code, such a ORIGEN); Easy (for computer implementation and analysis). We have illustrated with real SNM data using CPR for age dating and spoof detection. If SNM is pure, may use CPR to derive its age. If SNM is mixed, CPR will indicate that it is mixed or spoofed.

  7. Combined use of relative and numerical dating techniques for detecting signals of Alpine landscape evolution during the late Pleistocene and early Holocene in Val di Rabbi (Trentino, northern Italy)

    NASA Astrophysics Data System (ADS)

    Favilli, F.; Egli, M.; Brandova, D.; Ivy-Ochs, S.; Kubik, P.; Cherubini, P.; Mirabella, A.; Sartori, G.; Giaccai, D.; Haeberli, W.

    2009-04-01

    A combined use of relative and absolute dating techniques was applied on nine soil profiles in order to reconstruct late Pleistocene and early Holocene landscape evolution in an Alpine environment located in Val di Rabbi (Trentino, northern Italy). The degree of podzolisation, clay mineral evolution and element mass balances of each site were investigated. Furthermore, the stable fraction of the soil organic matter (SOM) was extracted from selected horizons with 10% H2O2 and 14C-dated. The ages of the organic residues were compared with the ages of charcoal fragments found in one of the studied soils and with the ages of rock boulders obtained by the surface exposure dating (SED) method with cosmogenic 10Be. The combination of 14C dating of SOM and SED indicated that deglaciation processes in Val di Rabbi were very much advanced around 14000 cal BP and that glacier oscillations have affected the highest part of the region until about 9000 cal BP. The development of clay mineral reflects weathering intensity. We found a close link between secondary clay minerals like smectite and vermiculite and soil age as obtained by H2O2. The degree of podzolisation is time dependent and was used as an evidence of surface stability. The amount of Fe and Al forms that migrated and accumulated in the illuvial horizon correlated well with the time of soil development. Element mass balance calculations strongly correlated with the ages derived from 14C measurements. Old soils have lost a major part of base cations (up to 75%), Fe and Al. Chemical and mineralogical analyses were in good agreement with numerical dating techniques, showing the dynamics of an Alpine landscape within a relatively small area and enabling a relative and absolute differentiation of landscape elements. The combination of relative and numerical dating techniques is a promising tool to understand landscape evolution and to provide absolute chronologies of the Late glacial in high-elevation Alpine areas with

  8. Effect of Absolute From Hibiscus syriacus L. Flower on Wound Healing in Keratinocytes

    PubMed Central

    Yoon, Seok Won; Lee, Kang Pa; Kim, Do-Yoon; Hwang, Dae Il; Won, Kyung-Jong; Lee, Dae Won; Lee, Hwan Myung

    2017-01-01

    Background: Proliferation and migration of keratinocytes are essential for the repair of cutaneous wounds. Hibiscus syriacus L. has been used in Asian medicine; however, research on keratinocytes is inadequate. Objective: To establish the dermatological properties of absolute from Hibiscus syriacus L. flower (HSF) and to provide fundamental research for alternative medicine. Materials and Methods: We identified the composition of HSF absolute using gas chromatography-mass spectrometry analysis. We also examined the effect of HSF absolute in HaCaT cells using the XTT assay, Boyden chamber assay, sprout-out growth assay, and western blotting. We conducted an in-vivo wound healing assay in rat tail-skin. Results: Ten major active compounds were identified from HSF absolute. As determined by the XTT assay, Boyden chamber assay, and sprout-out growth assay results, HSF absolute exhibited similar effects as that of epidermal growth factor on the proliferation and migration patterns of keratinocytes (HaCaT cells), which were significantly increased after HSF absolute treatment. The expression levels of the phosphorylated signaling proteins relevant to proliferation, including extracellular signal-regulated kinase 1/2 (Erk 1/2) and Akt, were also determined by western blot analysis. Conclusion: These results of our in-vitro and ex-vivo studies indicate that HSF absolute induced cell growth and migration of HaCaT cells by phosphorylating both Erk 1/2 and Akt. Moreover, we confirmed the wound-healing effect of HSF on injury of the rat tail-skin. Therefore, our results suggest that HSF absolute is promising for use in cosmetics and alternative medicine. SUMMARY Hisbiscus syriacus L. flower absolute increases HaCaT cell migration and proliferation.Hisbiscus syriacus L. flower absolute regulates phosphorylation of ERK 1/2 and Akt in HaCaT cell.Treatment with Hisbiscus syriacus L. flower induced sprout outgrowth.The wound in the tail-skin of rat was reduced by Hisbiscus syriacus

  9. Radiometric dating of the Siloam Tunnel, Jerusalem.

    PubMed

    Frumkin, Amos; Shimron, Aryeh; Rosenbaum, Jeff

    2003-09-11

    The historical credibility of texts from the Bible is often debated when compared with Iron Age archaeological finds (refs. 1, 2 and references therein). Modern scientific methods may, in principle, be used to independently date structures that seem to be mentioned in the biblical text, to evaluate its historical authenticity. In reality, however, this approach is extremely difficult because of poor archaeological preservation, uncertainty in identification, scarcity of datable materials, and restricted scientific access into well-identified worship sites. Because of these problems, no well-identified Biblical structure has been radiometrically dated until now. Here we report radiocarbon and U-Th dating of the Siloam Tunnel, proving its Iron Age II date; we conclude that the Biblical text presents an accurate historic record of the Siloam Tunnel's construction. Being one of the longest ancient water tunnels lacking intermediate shafts, dating the Siloam Tunnel is a key to determining where and when this technological breakthrough took place. Siloam Tunnel dating also refutes a claim that the tunnel was constructed in the second century bc.

  10. VIEW OF DATE DRIVE, SHOWING DATE PALMS. NOTE TRELLIS ON ...

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

    VIEW OF DATE DRIVE, SHOWING DATE PALMS. NOTE TRELLIS ON TYPE 11 FACILITY, FACILITY 808. VIEW FACING NORTHWEST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  11. Absolute calibration for complex-geometry biomedical diffuse optical spectroscopy

    NASA Astrophysics Data System (ADS)

    Mastanduno, Michael A.; Jiang, Shudong; El-Ghussein, Fadi; diFlorio-Alexander, Roberta; Pogue, Brian W.; Paulsen, Keith D.

    2013-03-01

    We have presented methodology to calibrate data in NIRS/MRI imaging versus an absolute reference phantom and results in both phantoms and healthy volunteers. This method directly calibrates data to a diffusion-based model, takes advantage of patient specific geometry from MRI prior information, and generates an initial guess without the need for a large data set. This method of calibration allows for more accurate quantification of total hemoglobin, oxygen saturation, water content, scattering, and lipid concentration as compared with other, slope-based methods. We found the main source of error in the method to be derived from incorrect assignment of reference phantom optical properties rather than initial guess in reconstruction. We also present examples of phantom and breast images from a combined frequency domain and continuous wave MRI-coupled NIRS system. We were able to recover phantom data within 10% of expected contrast and within 10% of the actual value using this method and compare these results with slope-based calibration methods. Finally, we were able to use this technique to calibrate and reconstruct images from healthy volunteers. Representative images are shown and discussion is provided for comparison with existing literature. These methods work towards fully combining the synergistic attributes of MRI and NIRS for in-vivo imaging of breast cancer. Complete software and hardware integration in dual modality instruments is especially important due to the complexity of the technology and success will contribute to complex anatomical and molecular prognostic information that can be readily obtained in clinical use.

  12. Absolute calibration of forces in optical tweezers

    NASA Astrophysics Data System (ADS)

    Dutra, R. S.; Viana, N. B.; Maia Neto, P. A.; Nussenzveig, H. M.

    2014-07-01

    Optical tweezers are highly versatile laser traps for neutral microparticles, with fundamental applications in physics and in single molecule cell biology. Force measurements are performed by converting the stiffness response to displacement of trapped transparent microspheres, employed as force transducers. Usually, calibration is indirect, by comparison with fluid drag forces. This can lead to discrepancies by sizable factors. Progress achieved in a program aiming at absolute calibration, conducted over the past 15 years, is briefly reviewed. Here we overcome its last major obstacle, a theoretical overestimation of the peak stiffness, within the most employed range for applications, and we perform experimental validation. The discrepancy is traced to the effect of primary aberrations of the optical system, which are now included in the theory. All required experimental parameters are readily accessible. Astigmatism, the dominant effect, is measured by analyzing reflected images of the focused laser spot, adapting frequently employed video microscopy techniques. Combined with interface spherical aberration, it reveals a previously unknown window of instability for trapping. Comparison with experimental data leads to an overall agreement within error bars, with no fitting, for a broad range of microsphere radii, from the Rayleigh regime to the ray optics one, for different polarizations and trapping heights, including all commonly employed parameter domains. Besides signaling full first-principles theoretical understanding of optical tweezers operation, the results may lead to improved instrument design and control over experiments, as well as to an extended domain of applicability, allowing reliable force measurements, in principle, from femtonewtons to nanonewtons.

  13. Elevation correction factor for absolute pressure measurements

    NASA Technical Reports Server (NTRS)

    Panek, Joseph W.; Sorrells, Mark R.

    1996-01-01

    With the arrival of highly accurate multi-port pressure measurement systems, conditions that previously did not affect overall system accuracy must now be scrutinized closely. Errors caused by elevation differences between pressure sensing elements and model pressure taps can be quantified and corrected. With multi-port pressure measurement systems, the sensing elements are connected to pressure taps that may be many feet away. The measurement system may be at a different elevation than the pressure taps due to laboratory space or test article constraints. This difference produces a pressure gradient that is inversely proportional to height within the interface tube. The pressure at the bottom of the tube will be higher than the pressure at the top due to the weight of the tube's column of air. Tubes with higher pressures will exhibit larger absolute errors due to the higher air density. The above effect is well documented but has generally been taken into account with large elevations only. With error analysis techniques, the loss in accuracy from elevation can be easily quantified. Correction factors can be applied to maintain the high accuracies of new pressure measurement systems.

  14. What is Needed for Absolute Paleointensity?

    NASA Astrophysics Data System (ADS)

    Valet, J. P.

    2015-12-01

    Many alternative approaches to the Thellier and Thellier technique for absolute paleointensity have been proposed during the past twenty years. One reason is the time consuming aspect of the experiments. Another reason is to avoid uncertainties in determinations of the paleofield which are mostly linked to the presence of multidomain grains. Despite great care taken by these new techniques, there is no indication that they always provide the right answer and in fact sometimes fail. We are convinced that the most valid approach remains the original double heating Thellier protocol provided that natural remanence is controlled by pure magnetite with a narrow distribution of small grain sizes, mostly single domains. The presence of titanium, even in small amount generates biases which yield incorrect field values. Single domain grains frequently dominate the magnetization of glass samples, which explains the success of this selective approach. They are also present in volcanic lava flows but much less frequently, and therefore contribute to the low success rate of most experiments. However the loss of at least 70% of the magnetization at very high temperatures prior to the Curie point appears to be an essential prerequisite that increases the success rate to almost 100% and has been validated from historical flows and from recent studies. This requirement can easily be tested by thermal demagnetization while low temperature experiments can document the detection of single domain magnetite using the δFC/δZFC parameter as suggested (Moskowitz et al, 1993) for biogenic magnetite.

  15. Gyrokinetic Statistical Absolute Equilibrium and Turbulence

    SciTech Connect

    Jian-Zhou Zhu and Gregory W. Hammett

    2011-01-10

    A paradigm based on the absolute equilibrium of Galerkin-truncated inviscid systems to aid in understanding turbulence [T.-D. Lee, "On some statistical properties of hydrodynamical and magnetohydrodynamical fields," Q. Appl. Math. 10, 69 (1952)] is taken to study gyrokinetic plasma turbulence: A finite set of Fourier modes of the collisionless gyrokinetic equations are kept and the statistical equilibria are calculated; possible implications for plasma turbulence in various situations are discussed. For the case of two spatial and one velocity dimension, in the calculation with discretization also of velocity v with N grid points (where N + 1 quantities are conserved, corresponding to an energy invariant and N entropy-related invariants), the negative temperature states, corresponding to the condensation of the generalized energy into the lowest modes, are found. This indicates a generic feature of inverse energy cascade. Comparisons are made with some classical results, such as those of Charney-Hasegawa-Mima in the cold-ion limit. There is a universal shape for statistical equilibrium of gyrokinetics in three spatial and two velocity dimensions with just one conserved quantity. Possible physical relevance to turbulence, such as ITG zonal flows, and to a critical balance hypothesis are also discussed.

  16. Climate Absolute Radiance and Refractivity Observatory (CLARREO)

    NASA Technical Reports Server (NTRS)

    Leckey, John P.

    2015-01-01

    The Climate Absolute Radiance and Refractivity Observatory (CLARREO) is a mission, led and developed by NASA, that will measure a variety of climate variables with an unprecedented accuracy to quantify and attribute climate change. CLARREO consists of three separate instruments: an infrared (IR) spectrometer, a reflected solar (RS) spectrometer, and a radio occultation (RO) instrument. The mission will contain orbiting radiometers with sufficient accuracy, including on orbit verification, to calibrate other space-based instrumentation, increasing their respective accuracy by as much as an order of magnitude. The IR spectrometer is a Fourier Transform spectrometer (FTS) working in the 5 to 50 microns wavelength region with a goal of 0.1 K (k = 3) accuracy. The FTS will achieve this accuracy using phase change cells to verify thermistor accuracy and heated halos to verify blackbody emissivity, both on orbit. The RS spectrometer will measure the reflectance of the atmosphere in the 0.32 to 2.3 microns wavelength region with an accuracy of 0.3% (k = 2). The status of the instrumentation packages and potential mission options will be presented.

  17. Absolute flux measurements for swift atoms

    NASA Technical Reports Server (NTRS)

    Fink, M.; Kohl, D. A.; Keto, J. W.; Antoniewicz, P.

    1987-01-01

    While a torsion balance in vacuum can easily measure the momentum transfer from a gas beam impinging on a surface attached to the balance, this measurement depends on the accommodation coefficients of the atoms with the surface and the distribution of the recoil. A torsion balance is described for making absolute flux measurements independent of recoil effects. The torsion balance is a conventional taut suspension wire design and the Young modulus of the wire determines the relationship between the displacement and the applied torque. A compensating magnetic field is applied to maintain zero displacement and provide critical damping. The unique feature is to couple the impinging gas beam to the torsion balance via a Wood's horn, i.e., a thin wall tube with a gradual 90 deg bend. Just as light is trapped in a Wood's horn by specular reflection from the curved surfaces, the gas beam diffuses through the tube. Instead of trapping the beam, the end of the tube is open so that the atoms exit the tube at 90 deg to their original direction. Therefore, all of the forward momentum of the gas beam is transferred to the torsion balance independent of the angle of reflection from the surfaces inside the tube.

  18. Dating human bone: is racemization dating species-specific?

    PubMed

    Moini, Mehdi; Rollman, Christopher M; France, Christine A M

    2013-12-03

    Our recently developed dating technique based on the racemization rate of aspartic acid was applied to dating human bone, as well as that of other mammals, utilizing capillary electrophoresis mass spectrometry. First, several well-dated (mostly (14)C-dated and with strong archeological evidence) human bones ranging in age from 150 to ~10,000 years were used to develop a calibration curve for human bone. The D/L ratio of aspartic acid for these specimens ranged from 2.4% to ~10%, with a correlation coefficient of better than 0.99, indicating a strong linear relationship between the d/l ratio of aspartic acid and the age of the specimens. This calibration curve can now be used to date human archeological specimens of unknown age, up to ~10,000 years. However, when the technique was applied to well-dated mixed species of larger mammal bones such as bison, whale, llama, etc., the calibration curve showed a slower rate of racemization with a lower correlation (0.88). As additional large mammal bones with less certain age (i.e., using archeological evidence alone with no (14)C-dating) were dated the correlation coefficient decreased to 0.70. The correlation coefficient decreased further to 0.58 when the racemization data from all mammals (including human) were added to the calibration curve, indicating the importance of using well-dated, species-specific specimens for forming a calibration curve. This conclusion is consistent with our previously published calibration curve for a single species of silk (Bombyx mori), which followed the expected reversible first-order kinetics. These results support species specificity of amino acid racemization dating.

  19. Assignment of absolute stereostructures through quantum mechanics electronic and vibrational circular dichroism calculations.

    PubMed

    Dai, Peng; Jiang, Nan; Tan, Ren-Xiang

    2016-01-01

    Elucidation of absolute configuration of chiral molecules including structurally complex natural products remains a challenging problem in organic chemistry. A reliable method for assigning the absolute stereostructure is to combine the experimental circular dichroism (CD) techniques such as electronic and vibrational CD (ECD and VCD), with quantum mechanics (QM) ECD and VCD calculations. The traditional QM methods as well as their continuing developments make them more applicable with accuracy. Taking some chiral natural products with diverse conformations as examples, this review describes the basic concepts and new developments of QM approaches for ECD and VCD calculations in solution and solid states.

  20. Positioning, alignment and absolute pointing of the ANTARES neutrino telescope

    NASA Astrophysics Data System (ADS)

    Fehr, F.; Distefano, C.; Antares Collaboration

    2010-01-01

    A precise detector alignment and absolute pointing is crucial for point-source searches. The ANTARES neutrino telescope utilises an array of hydrophones, tiltmeters and compasses for the relative positioning of the optical sensors. The absolute calibration is accomplished by long-baseline low-frequency triangulation of the acoustic reference devices in the deep-sea with a differential GPS system at the sea surface. The absolute pointing can be independently verified by detecting the shadow of the Moon in cosmic rays.

  1. Absolute Measurement of Tilts via Fourier Analysis of Interferograms

    NASA Technical Reports Server (NTRS)

    Toland, Ronald W.

    2004-01-01

    The Fourier method of interferogram analysis requires the introduction of a constant tilt into the interferogram to serve as a carrier signal for information on the figure of the surface under test. This tilt is usually removed in the first steps of analysis and ignored thereafter. However, in the problem of aligning optical components and systems, knowledge of part orientation is crucial to proper instrument performance. This paper outlines an algorithm which uses the normally ignored carrier signal in Fourier analysis to compute an absolute tilt (orientation) of the test surface. We also provide a brief outline of how this technique, incorporated in a rotating Twyman-Green interferometer, can be used in alignment and metrology of optical systems.

  2. Absolute Measurement of Tilts via Fourier Analysis of Interferograms

    NASA Technical Reports Server (NTRS)

    Toland, Ronald W.

    2004-01-01

    The Fourier method of interferogram analysis requires the introduction of a constant tilt into the inteferogram to serve as a 'carrier signal' for information on the figure of the surface under test. This tilt is usually removed in the first steps of analysis and ignored thereafter. However, in the problem of aligning optical components and systems, knowledge of part orientation is crucial to proper instrument performance. This paper outlines an algorithm which uses the normally ignored carrier signal in Fourier analysis to compute an absolute tilt (orientation) of the test surface. We also provide a brief outline of how this technique, incorporated in a rotating Twyman-Green interferometer, can be used in alignment and metrology of optical systems.

  3. Full field imaging based instantaneous hyperspectral absolute refractive index measurement

    SciTech Connect

    Baba, Justin S; Boudreaux, Philip R

    2012-01-01

    Multispectral refractometers typically measure refractive index (RI) at discrete monochromatic wavelengths via a serial process. We report on the demonstration of a white light full field imaging based refractometer capable of instantaneous multispectral measurement of absolute RI of clear liquid/gel samples across the entire visible light spectrum. The broad optical bandwidth refractometer is capable of hyperspectral measurement of RI in the range 1.30 1.70 between 400nm 700nm with a maximum error of 0.0036 units (0.24% of actual) at 414nm for a = 1.50 sample. We present system design and calibration method details as well as results from a system validation sample.

  4. Superfast 3D absolute shape measurement using five binary patterns

    NASA Astrophysics Data System (ADS)

    Hyun, Jae-Sang; Zhang, Song

    2017-03-01

    This paper presents a method that recovers high-quality 3D absolute coordinates point by point with only five binary patterns. Specifically, three dense binary dithered patterns are used to compute the wrapped phase; and the average intensity is combined with two additional binary patterns to determine fringe order pixel by pixel in phase domain. The wrapped phase is temporarily unwrapped point by point by referring to the fringe order. We further developed a computational framework to reduce random noise impact due to dithering, defocusing and random noise. Since only five binary fringe patterns are required to recover one 3D frame, extremely high speed 3D shape measurement can be achieved. For example, we developed a system that captures 2D images at 3333 Hz, and thus performs 3D shape measurement at 667 Hz.

  5. Absolute blood velocity measured with a modified fundus camera

    NASA Astrophysics Data System (ADS)

    Duncan, Donald D.; Lemaillet, Paul; Ibrahim, Mohamed; Nguyen, Quan Dong; Hiller, Matthias; Ramella-Roman, Jessica

    2010-09-01

    We present a new method for the quantitative estimation of blood flow velocity, based on the use of the Radon transform. The specific application is for measurement of blood flow velocity in the retina. Our modified fundus camera uses illumination from a green LED and captures imagery with a high-speed CCD camera. The basic theory is presented, and typical results are shown for an in vitro flow model using blood in a capillary tube. Subsequently, representative results are shown for representative fundus imagery. This approach provides absolute velocity and flow direction along the vessel centerline or any lateral displacement therefrom. We also provide an error analysis allowing estimation of confidence intervals for the estimated velocity.

  6. Absolute stellar photometry on moderate-resolution FPA images

    USGS Publications Warehouse

    Stone, T.C.

    2009-01-01

    An extensive database of star (and Moon) images has been collected by the ground-based RObotic Lunar Observatory (ROLO) as part of the US Geological Survey program for lunar calibration. The stellar data are used to derive nightly atmospheric corrections for the observations from extinction measurements, and absolute calibration of the ROLO sensors is based on observations of Vega and published reference flux and spectrum data. The ROLO telescopes were designed for imaging the Moon at moderate resolution, thus imposing some limitations for the stellar photometry. Attaining accurate stellar photometry with the ROLO image data has required development of specialized processing techniques. A key consideration is consistency in discriminating the star core signal from the off-axis point spread function. The analysis and processing methods applied to the ROLO stellar image database are described. ?? 2009 BIPM and IOP Publishing Ltd.

  7. A three-axis SQUID-based absolute vector magnetometer.

    PubMed

    Schönau, T; Zakosarenko, V; Schmelz, M; Stolz, R; Anders, S; Linzen, S; Meyer, M; Meyer, H-G

    2015-10-01

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth's magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz(1/2). The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  8. Active radiometric calorimeter for absolute calibration of radioactive sources

    SciTech Connect

    Stump, K.E.; DeWerd, L.A.; Rudman, D.A.; Schima, S.A.

    2005-03-01

    This report describes the design and initial noise floor measurements of a radiometric calorimeter designed to measure therapeutic medical radioactive sources. The instrument demonstrates a noise floor of approximately 2 nW. This low noise floor is achieved by using high temperature superconducting (HTS) transition edge sensor (TES) thermometers in a temperature-control feedback loop. This feedback loop will be used to provide absolute source calibrations based upon the electrical substitution method. Other unique features of the calorimeter are (a) its ability to change sources for calibration without disrupting the vacuum of the instrument, and (b) the ability to measure the emitted power of a source in addition to the total contained source power.

  9. Absolute stress measurements at the rangely anticline, Northwestern Colorado

    USGS Publications Warehouse

    de la Cruz, R. V.; Raleigh, C.B.

    1972-01-01

    Five different methods of measuring absolute state of stress in rocks in situ were used at sites near Rangely, Colorado, and the results compared. For near-surface measurements, overcoring of the borehole-deformation gage is the most convenient and rapid means of obtaining reliable values for the magnitude and direction of the state of stress in rocks in situ. The magnitudes and directions of the principal stresses are compared to the geologic features of the different areas of measurement. The in situ stresses are consistent in orientation with the stress direction inferred from the earthquake focal-plane solutions and existing joint patterns but inconsistent with stress directions likely to have produced the Rangely anticline. ?? 1972.

  10. A three-axis SQUID-based absolute vector magnetometer

    SciTech Connect

    Schönau, T.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, H.-G.; Zakosarenko, V.; Meyer, M.

    2015-10-15

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz{sup 1/2}. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  11. Absolute and Convective Instability of a Liquid Jet

    NASA Technical Reports Server (NTRS)

    Lin, S. P.; Hudman, M.; Chen, J. N.

    1999-01-01

    The existence of absolute instability in a liquid jet has been predicted for some time. The disturbance grows in time and propagates both upstream and downstream in an absolutely unstable liquid jet. The image of absolute instability is captured in the NASA 2.2 sec drop tower and reported here. The transition from convective to absolute instability is observed experimentally. The experimental results are compared with the theoretical predictions on the transition Weber number as functions of the Reynolds number. The role of interfacial shear relative to all other relevant forces which cause the onset of jet breakup is explained.

  12. DATINK pilot study: an effective methodology for ballpoint pen ink dating in questioned documents.

    PubMed

    San Román, I; Bartolomé, L; Alonso, M L; Alonso, R M; Ezcurra, M

    2015-09-10

    Establishing the approximate age of an ink entry from a questioned document is often a complicated task and a controversial issue in forensic sciences. Among the existing approaches, the analysis of solvents in ballpoint inks may be a useful parameter for determining the age of ink on paper. In recent years, several ink dating methods have been proposed. These methods have been based on the analysis of common ink solvents using gas chromatography/mass spectrometry (GC/MS) as the analytical platform. Despite these recent methods, several questions remain. The aim of this work was to develop an ink dating methodology (DATINK) for documents written by ballpoint pens based on the disappearance of volatile solvents from the ink entry. Multiple solid-phase microextraction (MHS-SPME) coupled to GC/MS was used to measure the solvents from ink entries made with four BIC(®) ballpoint pens. The β parameter, the remaining fraction of the analyte in the system after one equilibration, corresponding to the successive extractions was considered for modelling a mathematical equation for later ink age dating. Preliminary tests of DATINK method showed that it was possible to detect the presence of ink solvents on documents up to the studied five years. The analyses of different real samples of known age were analyzed in terms of β values, which provided a mean relative error of 21%. The proposed use of β parameter for estimating the absolute age of ballpoint ink entries has shown promising results with a standard deviation of β ranging from 0.002 to 0.004.

  13. National Date Palm Germplasm Repository

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Clonal Germplasm Repository for Citrus & Dates (NCGRCD), located in Riverside, California USA, is a project of the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA). The NCGRCD maintains a collection of germplasm of date palm (Phoneix dactylifera ...

  14. Thorough subcells diagnosis in a multi-junction solar cell via absolute electroluminescence-efficiency measurements.

    PubMed

    Chen, Shaoqiang; Zhu, Lin; Yoshita, Masahiro; Mochizuki, Toshimitsu; Kim, Changsu; Akiyama, Hidefumi; Imaizumi, Mitsuru; Kanemitsu, Yoshihiko

    2015-01-16

    World-wide studies on multi-junction (tandem) solar cells have led to record-breaking improvements in conversion efficiencies year after year. To obtain detailed and proper feedback for solar-cell design and fabrication, it is necessary to establish standard methods for diagnosing subcells in fabricated tandem devices. Here, we propose a potential standard method to quantify the detailed subcell properties of multi-junction solar cells based on absolute measurements of electroluminescence (EL) external quantum efficiency in addition to the conventional solar-cell external-quantum-efficiency measurements. We demonstrate that the absolute-EL-quantum-efficiency measurements provide I-V relations of individual subcells without the need for referencing measured I-V data, which is in stark contrast to previous works. Moreover, our measurements quantify the absolute rates of junction loss, non-radiative loss, radiative loss, and luminescence coupling in the subcells, which constitute the "balance sheets" of tandem solar cells.

  15. Absolute Plate Velocities from Seismic Anisotropy

    NASA Astrophysics Data System (ADS)

    Kreemer, Corné; Zheng, Lin; Gordon, Richard

    2015-04-01

    The orientation of seismic anisotropy inferred beneath plate interiors may provide a means to estimate the motions of the plate relative to the sub-asthenospheric mantle. Here we analyze two global sets of shear-wave splitting data, that of Kreemer [2009] and an updated and expanded data set, to estimate plate motions and to better understand the dispersion of the data, correlations in the errors, and their relation to plate speed. We also explore the effect of using geologically current plate velocities (i.e., the MORVEL set of angular velocities [DeMets et al. 2010]) compared with geodetically current plate velocities (i.e., the GSRM v1.2 angular velocities [Kreemer et al. 2014]). We demonstrate that the errors in plate motion azimuths inferred from shear-wave splitting beneath any one tectonic plate are correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. The SKS-MORVEL absolute plate angular velocities (based on the Kreemer [2009] data set) are determined from the poles from eight plates weighted proportionally to the root-mean-square velocity of each plate. SKS-MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25±0.11° Ma-1 (95% confidence limits) right-handed about 57.1°S, 68.6°E. The within-plate dispersion of seismic anisotropy for oceanic lithosphere (σ=19.2° ) differs insignificantly from that for continental lithosphere (σ=21.6° ). The between-plate dispersion, however, is significantly smaller for oceanic lithosphere (σ=7.4° ) than for continental

  16. Absolute Measurements Of Methane On Mars: The Current Status.

    NASA Astrophysics Data System (ADS)

    Mumma, Michael J.; Villanueva, G. L.; Novak, R. E.; Hewagama, T.; Bonev, B. P.; DiSanti, M. A.; Smith, M. D.

    2008-09-01

    Our study of methane on Mars now extends over three Mars years, sampling a wide range of seasons with significant spatial coverage. Three spectrometer-telescope combinations were used. With the spectrometer slit oriented North-South on the planet, we obtain simultaneous spectra at latitudes along the central meridian. Successive longitudes are sampled as the planet rotates, and the combination then permits partial mapping of the planet. We earlier reported differential detections of methane and water on Mars. Here, we present absolute extractions of methane, based on improved analytical procedures developed since 2005. We now identify and correct instrumental effects such as variations in resolving power along the slit, second-order optical fringe removal, and correction of (minor) internal scattered light. We synthesize the fully-resolved terrestrial transmittance spectrum, convolve it to the instrumental resolution, and subtract it from the measured Mars-Earth spectrum. Fraunhofer lines are removed from the residual Mars spectra along with spectral lines of water and of (newly identified by us) carbon dioxide isotopomers. The residuals are then inspected for signatures of methane and other possible trace constituents such as HDO and H2O (Villanueva et al., this Conference). On certain dates, the residual spectra display spectral lines at the Doppler-shifted positions expected for methane on Mars. The positive indications favor certain seasons (e.g., Ls = 121° & 155°) and locations. Mixing ratios derived from those residuals (up to 60 ppb) greatly exceed upper limits obtained at other seasons (e.g., < 3ppb at Ls = 17°) these variations could be consistent with episodic release. The CH4 spatial extent requires transport over large distances (coupled with eddy diffusion), and destruction lifetimes of order one year. Details will be presented and implications will be discussed. This work was supported by NASA's Astrobiology, Planetary Astronomy, and Postdoctoral

  17. Orion Absolute Navigation System Progress and Challenge

    NASA Technical Reports Server (NTRS)

    Holt, Greg N.; D'Souza, Christopher

    2012-01-01

    The absolute navigation design of NASA's Orion vehicle is described. It has undergone several iterations and modifications since its inception, and continues as a work-in-progress. This paper seeks to benchmark the current state of the design and some of the rationale and analysis behind it. There are specific challenges to address when preparing a timely and effective design for the Exploration Flight Test (EFT-1), while still looking ahead and providing software extensibility for future exploration missions. The primary onboard measurements in a Near-Earth or Mid-Earth environment consist of GPS pseudo-range and delta-range, but for future explorations missions the use of star-tracker and optical navigation sources need to be considered. Discussions are presented for state size and composition, processing techniques, and consider states. A presentation is given for the processing technique using the computationally stable and robust UDU formulation with an Agee-Turner Rank-One update. This allows for computational savings when dealing with many parameters which are modeled as slowly varying Gauss-Markov processes. Preliminary analysis shows up to a 50% reduction in computation versus a more traditional formulation. Several state elements are discussed and evaluated, including position, velocity, attitude, clock bias/drift, and GPS measurement biases in addition to bias, scale factor, misalignment, and non-orthogonalities of the accelerometers and gyroscopes. Another consideration is the initialization of the EKF in various scenarios. Scenarios such as single-event upset, ground command, and cold start are discussed as are strategies for whole and partial state updates as well as covariance considerations. Strategies are given for dealing with latent measurements and high-rate propagation using multi-rate architecture. The details of the rate groups and the data ow between the elements is discussed and evaluated.

  18. Evaluation of the Absolute Regional Temperature Potential

    NASA Technical Reports Server (NTRS)

    Shindell, D. T.

    2012-01-01

    The Absolute Regional Temperature Potential (ARTP) is one of the few climate metrics that provides estimates of impacts at a sub-global scale. The ARTP presented here gives the time-dependent temperature response in four latitude bands (90-28degS, 28degS-28degN, 28-60degN and 60-90degN) as a function of emissions based on the forcing in those bands caused by the emissions. It is based on a large set of simulations performed with a single atmosphere-ocean climate model to derive regional forcing/response relationships. Here I evaluate the robustness of those relationships using the forcing/response portion of the ARTP to estimate regional temperature responses to the historic aerosol forcing in three independent climate models. These ARTP results are in good accord with the actual responses in those models. Nearly all ARTP estimates fall within +/-20%of the actual responses, though there are some exceptions for 90-28degS and the Arctic, and in the latter the ARTP may vary with forcing agent. However, for the tropics and the Northern Hemisphere mid-latitudes in particular, the +/-20% range appears to be roughly consistent with the 95% confidence interval. Land areas within these two bands respond 39-45% and 9-39% more than the latitude band as a whole. The ARTP, presented here in a slightly revised form, thus appears to provide a relatively robust estimate for the responses of large-scale latitude bands and land areas within those bands to inhomogeneous radiative forcing and thus potentially to emissions as well. Hence this metric could allow rapid evaluation of the effects of emissions policies at a finer scale than global metrics without requiring use of a full climate model.

  19. Thermoluminescence dating of Hawaiian basalt

    USGS Publications Warehouse

    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

  20. Estimating Divergence Dates and Substitution Rates in the Drosophila Phylogeny

    PubMed Central

    Obbard, Darren J.; Maclennan, John; Kim, Kang-Wook; Rambaut, Andrew; O’Grady, Patrick M.; Jiggins, Francis M.

    2012-01-01

    An absolute timescale for evolution is essential if we are to associate evolutionary phenomena, such as adaptation or speciation, with potential causes, such as geological activity or climatic change. Timescales in most phylogenetic studies use geologically dated fossils or phylogeographic events as calibration points, but more recently, it has also become possible to use experimentally derived estimates of the mutation rate as a proxy for substitution rates. The large radiation of drosophilid taxa endemic to the Hawaiian islands has provided multiple calibration points for the Drosophila phylogeny, thanks to the "conveyor belt" process by which this archipelago forms and is colonized by species. However, published date estimates for key nodes in the Drosophila phylogeny vary widely, and many are based on simplistic models of colonization and coalescence or on estimates of island age that are not current. In this study, we use new sequence data from seven species of Hawaiian Drosophila to examine a range of explicit coalescent models and estimate substitution rates. We use these rates, along with a published experimentally determined mutation rate, to date key events in drosophilid evolution. Surprisingly, our estimate for the date for the most recent common ancestor of the genus Drosophila based on mutation rate (25–40 Ma) is closer to being compatible with independent fossil-derived dates (20–50 Ma) than are most of the Hawaiian-calibration models and also has smaller uncertainty. We find that Hawaiian-calibrated dates are extremely sensitive to model choice and give rise to point estimates that range between 26 and 192 Ma, depending on the details of the model. Potential problems with the Hawaiian calibration may arise from systematic variation in the molecular clock due to the long generation time of Hawaiian Drosophila compared with other Drosophila and/or uncertainty in linking island formation dates with colonization dates. As either source of error will