WorldWideScience

Sample records for atom counting qspr

  1. An Atom Counting QSPR Protocol

    CERN Document Server

    Giri, S; Chattaraj, P K; Roy, D R; Subramanian, V

    2006-01-01

    A deceptively simple descriptor, viz. the number of carbon / non-hydrogenic atoms present in a molecule, is proposed for the development of useful quantitative-structure-property-relationship (QSPR) models. It is tested in models pertaining to the estimation of boiling point of alcohols, enthalpy of vaporization of polychlorinated biphenyls (PCBs), n-octanol / water partition coefficient of PCBs and chloroanisoles, pKa values of carboxylic acids, phenols and alcohols etc. Very high values of various regression coefficients (R2, R2CV, R2Ad) suggest the significance of this descriptor which further improves in the resulting two-parameter QSPR models with electrophilicity or its local variant as an additional descriptor.

  2. Resonance ionization spectroscopy: Counting noble gas atoms

    International Nuclear Information System (INIS)

    The purpose of this paper is to describe new work on the counting of noble gas atoms, using lasers for the selective ionization and detectors for counting individual particles (electrons or positive ions). When positive ions are counted, various kinds of mass analyzers (magnetic, quadrupole, or time-of-flight) can be incorporated to provide A selectivity. We show that a variety of interesting and important applications can be made with atom-counting techniques which are both atomic number (Z) and mass number (A) selective. (orig./FKS)

  3. QSPR Calculation of Normal Boiling Points of Organic Molecules Based on the Use of Correlation Weighting of Atomic Orbitals with Extended Connectivity of Zero- and First-Order Graphs of Atomic Orbitals

    Directory of Open Access Journals (Sweden)

    Eduardo A. Castro

    2004-12-01

    Full Text Available We report the results of a calculation of the normal boiling points of a representative set of 200 organic molecules through the application of QSPR theory. For this purpose we have used a particular set of flexible molecular descriptors, the so called Correlation Weighting of Atomic Orbitals with Extended Connectivity of Zero- and First-Order Graphs of Atomic Orbitals. Although in general the results show suitable behavior to predict this physical chemistry property, the existence of some deviant behaviors points to a need to complement this index with some other sort of molecular descriptors. Some possible extensions of this study are discussed.

  4. Radioactive krypton background evaluation using atom counting

    International Nuclear Information System (INIS)

    The beta-decay of 85Kr is a significant radioactive background for experiments that use liquified noble gases to search for dark matter and measure the low-energy solar neutrino flux. While there are several proposed methods for reducing Kr levels in these experiments, an independent technique is needed for measuring very low Kr levels. By selectively exciting Kr atoms to a metastable state, capturing them in a magneto-optical trap (MOT), and detecting fluorescence from the trapped atoms, individual Kr atoms can be counted with a high signal-to-noise ratio. This approach could be used to ascertain Kr impurity levels in other noble gases, with an estimated sensitivity of 3x10-14

  5. Resonance ionization spectroscopy: counting noble-gas atoms

    International Nuclear Information System (INIS)

    New work on the counting of noble gas atoms, using lasers for the selective ionization and detectors for counting individual particles (electrons or positive ions) is reported. When positive ions are counted, various kinds of mass analyzers (magnetic, quadrupole, or time-of-flight) can be incorporated to provide A selectivity. It is shown that a variety of interesting and important applications can be made with atom-counting techniques which are both atomic number (Z) and mass number (A) selective

  6. First AID (Atom counting for Isotopic Determination).

    Energy Technology Data Exchange (ETDEWEB)

    Roach, J. L. (Jeffrey L.); Israel, K. M. (Kimberly M.); Steiner, R. E. (Robert E.); Duffy, C. J. (Clarence J.); Roench, F. R. (Fred R.)

    2002-01-01

    Los Alamos National Laboratory (LANL) has established an in vitro bioassay monitoring program in compliance with the requirements in the Code of Federal Regulations, 10 CFR 835, Occupational Radiation Protection. One aspect of this program involves monitoring plutonium levels in at-risk workers. High-risk workers are monitored using the ultra-sensitive Therrnal Ionization Mass Spectrometry (TIMS) technique to ensure compliance with DOE standards. TIMS is used to measure atom ratios of 239Pua nd 240Puw ith respect to a tracer isotope ('Pu). These ratios are then used to calculate the amount of 239Pu and 240Pup resent. This low-level atom counting technique allows the calculation of the concentration levels of 239Pu and 240Pu in urine for at risk workers. From these concentration levels, dose assessments can be made and worker exposure levels can be monitored. Detection limits for TIMS analysis are on the order of millions of atoms, which translates to activity levels of 150 aCi 239Pua nd 500 aCi for 240Pu. pCi for Our poster presentation will discuss the ultra-sensitive, low-level analytical technique used to measure plutonium isotopes and the data verification methods used for validating isotopic measurements.

  7. Atom, Atom-Type, and Total Linear Indices of the “Molecular Pseudograph’s Atom Adjacency Matrix”: Application to QSPR/QSAR Studies of Organic Compounds

    Directory of Open Access Journals (Sweden)

    Eduardo A. Castro

    2004-12-01

    Full Text Available In this paper we describe the application in QSPR/QSAR studies of a newgroup of molecular descriptors: atom, atom-type and total linear indices of the molecularpseudograph’s atom adjacency matrix. These novel molecular descriptors were used forthe prediction of boiling point and partition coefficient (log P, specific rate constant (logk, and antibacterial activity of 28 alkyl-alcohols and 34 derivatives of 2-furylethylenes,respectively. For this purpose two quantitative models were obtained to describe thealkyl-alcohols’ boiling points. The first one includes only two total linear indices andshowed a good behavior from a statistical point of view (R2 = 0.984, s = 3.78, F = 748.57,q2 = 0.981, and scv = 3.91. The second one includes four variables [3 global and 1 local(heteroatom linear indices] and it showed an improvement in the description of physicalproperty (R2 = 0.9934, s = 2.48, F = 871.96, q2 = 0.990, and scv = 2.79. Later, linearmultiple regression analysis was also used to describe log P and log k of the 2-furyl-ethylenes derivatives. These models were statistically significant [(R2 = 0.984, s = 0.143, and F = 113.38 and (R2 = 0.973, s = 0.26 and F = 161.22, respectively] and showed very good stability to data variation in leave-one-out (LOO cross-validation experiment [(q2 = 0.93.8 and scv = 0.178 and (q2 = 0.948 and scv = 0.33, respectively]. Finally, a linear discriminant model for classifying antibacterial activity of these compounds was also achieved with the use of the atom and atom-type linear indices. The global percent of good classification in training and external test set obtained was of 94.12% and 100.0%, respectively. The comparison with other approaches (connectivity indices, total and local spectral moments, quantum chemical descriptors, topographic indices and E- state/biomolecular encounter parameters reveals a good behavior of our method. The approach described in this paper appears to be a

  8. Three L-subshells atomic model to compute counting efficiency of electron-capture nuclides

    International Nuclear Information System (INIS)

    The present paper develops a three L-subshell a and K, M-a hells atomic model in order to obtain the counting efficiency in liquid scintillation counting. Mathematical expressions are given to calculate the probabilities of 264 different atomic rearrangement way so as the corresponding effective energies. This new model will permit to test the influence of the different atomic and nuclear parameters upon the counting efficiency nuclides of low and medium atomic number decaying by electron capture. (Author) 8 refs

  9. A quantitative structure-property relationship (QSPR) study of singlet oxygen generation by pteridines.

    Science.gov (United States)

    Buglak, Andrey A; Telegina, Taisiya A; Kritsky, Mikhail S

    2016-06-01

    The QSPR method is used in photochemistry for the prediction of the absorption wavelength, fluorescence intensity, photolysis quantum yield, etc. However, to our knowledge, no attempts have been made to use the quantum yield of singlet oxygen ((1)O2) generation (ΦΔ) as an analyzed parameter in a QSPR study. We performed QSPR analysis of 29 pteridine compounds (including pterin and flavin sensitizers) for their ability to produce singlet oxygen in aqueous (D2O) solutions. Pteridines are ubiquitously present in living systems (mostly as coenzymes), possess high photochemical activity and have multiple applications as photosensitizers. Our goal was to develop a QSPR model for the fast virtual screening and prediction of the (1)O2 generation quantum yield of pteridines. Quantum-chemical descriptors were calculated using the AM1 semi-empirical method. The ability of pteridines to generate singlet oxygen was found to be significantly correlated with the HOMO orbital energy (R(2) = 0.806) and electronegativity (R(2) = 0.840). The best QSPR model obtained using electronegativity, dipole density and electrostatic charge of the N3 atom of the pteridine system allows us to predict ΦΔ of pterin and flavin photosensitizers. The model possesses high internal stability (q(2) = 0.881), as well as high predicting ability for the external dataset (pred_R(2) = 0.873). More QSPR analysis is needed for the prediction of ΦΔ of pteridines and other groups of sensitizers in aqueous as well as in non-polar solutions. PMID:27216311

  10. Isotopically selective counting of noble gas atoms, using resonance ionization spectroscopy

    International Nuclear Information System (INIS)

    The technique of Resonance Ionization Spectroscopy (RIS) is being extended to develop a means for counting individual atoms of a selected isotope of a noble gas. In this method, lasers are used for RIS to obtain atomic species (Z) selectivity and a small quadrupole mass spectrometer provides isotopic (A) selectivity. A progress report on the objective of counting each atom of a particular isotope of a noble gas is given. (author)

  11. Isotopically selective counting of noble gas atoms, using resonance ionization spectroscopy

    International Nuclear Information System (INIS)

    The technique of Resonance Ionization Spectroscopy (RIS) is being extended to develop a means for counting individual atoms of a selected isotope of a noble gas. In this method, lasers are used for RIS to obtain atomic species (Z) selectivity and a small quadrupole mass spectrometer provides isotopic (A) selectivity. A progress report on the objective of counting each atom of a particular isotope of a noble gas is given. 10 references, 4 figures

  12. A Review on Progress in QSPR Studies for Surfactants

    OpenAIRE

    Zhengwu Wang; Xiaoyi Zhang; Jiwei Hu

    2010-01-01

    This paper presents a review on recent progress in quantitative structure-property relationship (QSPR) studies of surfactants and applications of various molecular descriptors. QSPR studies on critical micelle concentration (cmc) and surface tension (γ) of surfactants are introduced. Studies on charge distribution in ionic surfactants by quantum chemical calculations and its effects on the structures and properties of the colloids of surfactants are also reviewed. The trends of QSPR studies o...

  13. Estimation of atomic interaction parameters by photon counting

    DEFF Research Database (Denmark)

    Kiilerich, Alexander Holm; Mølmer, Klaus

    2014-01-01

    Detection of radiation signals is at the heart of precision metrology and sensing. In this article we show how the fluctuations in photon counting signals can be exploited to optimally extract information about the physical parameters that govern the dynamics of the emitter. For a simple two...

  14. Optimal experimental design for nano-particle atom-counting from high-resolution STEM images

    Energy Technology Data Exchange (ETDEWEB)

    De Backer, A.; De wael, A.; Gonnissen, J.; Van Aert, S., E-mail: sandra.vanaert@uantwerpen.be

    2015-04-15

    In the present paper, the principles of detection theory are used to quantify the probability of error for atom-counting from high resolution scanning transmission electron microscopy (HR STEM) images. Binary and multiple hypothesis testing have been investigated in order to determine the limits to the precision with which the number of atoms in a projected atomic column can be estimated. The probability of error has been calculated when using STEM images, scattering cross-sections or peak intensities as a criterion to count atoms. Based on this analysis, we conclude that scattering cross-sections perform almost equally well as images and perform better than peak intensities. Furthermore, the optimal STEM detector design can be derived for atom-counting using the expression for the probability of error. We show that for very thin objects LAADF is optimal and that for thicker objects the optimal inner detector angle increases.

  15. Optimal experimental design for nano-particle atom-counting from high-resolution STEM images

    International Nuclear Information System (INIS)

    In the present paper, the principles of detection theory are used to quantify the probability of error for atom-counting from high resolution scanning transmission electron microscopy (HR STEM) images. Binary and multiple hypothesis testing have been investigated in order to determine the limits to the precision with which the number of atoms in a projected atomic column can be estimated. The probability of error has been calculated when using STEM images, scattering cross-sections or peak intensities as a criterion to count atoms. Based on this analysis, we conclude that scattering cross-sections perform almost equally well as images and perform better than peak intensities. Furthermore, the optimal STEM detector design can be derived for atom-counting using the expression for the probability of error. We show that for very thin objects LAADF is optimal and that for thicker objects the optimal inner detector angle increases

  16. Current Mathematical Methods Used in QSAR/QSPR Studies

    Directory of Open Access Journals (Sweden)

    Peixun Liu

    2009-04-01

    Full Text Available This paper gives an overview of the mathematical methods currently used in quantitative structure-activity/property relationship (QASR/QSPR studies. Recently, the mathematical methods applied to the regression of QASR/QSPR models are developing very fast, and new methods, such as Gene Expression Programming (GEP, Project Pursuit Regression (PPR and Local Lazy Regression (LLR have appeared on the QASR/QSPR stage. At the same time, the earlier methods, including Multiple Linear Regression (MLR, Partial Least Squares (PLS, Neural Networks (NN, Support Vector Machine (SVM and so on, are being upgraded to improve their performance in QASR/QSPR studies. These new and upgraded methods and algorithms are described in detail, and their advantages and disadvantages are evaluated and discussed, to show their application potential in QASR/QSPR studies in the future.

  17. An atom counting and electrophilicity based QSTR approach

    Indian Academy of Sciences (India)

    P K Chattara; D R Roy; S Giri; S Mukherjee; V Subramanian; R Parthasarathi; P Bultinck; S Van Damme

    2007-09-01

    Quantitative-structure-toxicity-relationship (QSTR) models are developed for predicting the toxicity (pIGC50) of 252 aliphatic compounds on Tetrahymena pyriformis. The single parameter models with a simple molecular descriptor, the number of atoms in the molecule, provide reasonable results. Better QSTR models with two parameters result when global electrophilicity is used as the second descriptor. In order to tackle both charge- and frontier-controlled reactions the importance of the local electro (nucleo) philicities and atomic charges is also analysed.

  18. Four shells atomic model to computer the counting efficiency of electron-capture nuclides

    International Nuclear Information System (INIS)

    The present paper develops a four-shells atomic model in order to obtain the efficiency of detection in liquid scintillation courting, Mathematical expressions are given to calculate the probabilities of the 229 different atomic rearrangements so as the corresponding effective energies. This new model will permit the study of the influence of the different parameters upon the counting efficiency for nuclides of high atomic number. (Author) 7 refs

  19. Microwave single photon counting by using Rydberg atoms and its application for searching invisible axions

    International Nuclear Information System (INIS)

    A high sensitivity single photon counting method using Rydberg atoms is discussed and shown to be a promissing technique for detecting microwave photons converted from cosmic axions in a strong magnetic field by the Primakov effect. This method could give much better results compared with conventional methods. (author)

  20. The Correlation of the NA Measurements by Counting 28Si Atoms

    International Nuclear Information System (INIS)

    An additional value of the Avogadro constant was obtained by counting the atoms in isotopically enriched Si spheres. With respect to the previous determination, the spheres were etched and repolished to eliminate metal contaminations and to improve the roundness. In addition, all the input quantities—molar mass, lattice parameter, mass, and volume—were remeasured aiming at a smaller uncertainty. In order to make the values given in Andreas et al. [Metrologia 48, S1 (2011)] and Azuma et al. [Metrologia 52, 360 (2015)] usable for a least squares adjustment, we report about the estimate of their correlation

  1. An accurate determination of the Avogadro constant by counting the atoms in a 28Si crystal

    CERN Document Server

    Andreas, B; Bartl, G; Becker, P; Bettin, H; Borys, M; Busch, I; Gray, M; Fuchs, P; Fujii, K; Fujimoto, H; Kessler, E; Krumrey, M; Kuetgens, U; Kuramoto, N; Mana, G; Manson, P; Massa, E; Mizushima, S; Nicolaus, A; Picard, A; Pramann, A; Rienitz, O; Schiel, D; Valkiers, S; Waseda, A

    2010-01-01

    The Avogadro constant links the atomic and the macroscopic properties of matter. Since the molar Planck constant is well known via the measurement of the Rydberg constant, it is also closely related to the Planck constant. In addition, its accurate determination is of paramount importance for a definition of the kilogram in terms of a fundamental constant. We describe a new approach for its determination by "counting" the atoms in 1 kg single-crystal spheres, which are highly enriched with the 28Si isotope. It enabled isotope dilution mass spectroscopy to determine the molar mass of the silicon crystal with unprecedented accuracy. The value obtained, 6.02214084(18) x 10^23 mol^-1, is the most accurate input datum for a new definition of the kilogram.

  2. Predicting p Ka values from EEM atomic charges.

    Science.gov (United States)

    Vařeková, Radka Svobodová; Geidl, Stanislav; Ionescu, Crina-Maria; Skřehota, Ondřej; Bouchal, Tomáš; Sehnal, David; Abagyan, Ruben; Koča, Jaroslav

    2013-01-01

    : The acid dissociation constant p Ka is a very important molecular property, and there is a strong interest in the development of reliable and fast methods for p Ka prediction. We have evaluated the p Ka prediction capabilities of QSPR models based on empirical atomic charges calculated by the Electronegativity Equalization Method (EEM). Specifically, we collected 18 EEM parameter sets created for 8 different quantum mechanical (QM) charge calculation schemes. Afterwards, we prepared a training set of 74 substituted phenols. Additionally, for each molecule we generated its dissociated form by removing the phenolic hydrogen. For all the molecules in the training set, we then calculated EEM charges using the 18 parameter sets, and the QM charges using the 8 above mentioned charge calculation schemes. For each type of QM and EEM charges, we created one QSPR model employing charges from the non-dissociated molecules (three descriptor QSPR models), and one QSPR model based on charges from both dissociated and non-dissociated molecules (QSPR models with five descriptors). Afterwards, we calculated the quality criteria and evaluated all the QSPR models obtained. We found that QSPR models employing the EEM charges proved as a good approach for the prediction of p Ka (63% of these models had R2 > 0.9, while the best had R2 = 0.924). As expected, QM QSPR models provided more accurate p Ka predictions than the EEM QSPR models but the differences were not significant. Furthermore, a big advantage of the EEM QSPR models is that their descriptors (i.e., EEM atomic charges) can be calculated markedly faster than the QM charge descriptors. Moreover, we found that the EEM QSPR models are not so strongly influenced by the selection of the charge calculation approach as the QM QSPR models. The robustness of the EEM QSPR models was subsequently confirmed by cross-validation. The applicability of EEM QSPR models for other chemical classes was illustrated by a case study focused on

  3. Dose limited reliability of quantitative annular dark field scanning transmission electron microscopy for nano-particle atom-counting

    Energy Technology Data Exchange (ETDEWEB)

    De Backer, A.; Martinez, G.T. [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); MacArthur, K.E.; Jones, L. [Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH (United Kingdom); Béché, A. [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Nellist, P.D. [Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH (United Kingdom); Van Aert, S., E-mail: sandra.vanaert@uantwerpen.be [Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium)

    2015-04-15

    Quantitative annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique to characterise nano-particles on an atomic scale. Because of their limited size and beam sensitivity, the atomic structure of such particles may become extremely challenging to determine. Therefore keeping the incoming electron dose to a minimum is important. However, this may reduce the reliability of quantitative ADF STEM which will here be demonstrated for nano-particle atom-counting. Based on experimental ADF STEM images of a real industrial catalyst, we discuss the limits for counting the number of atoms in a projected atomic column with single atom sensitivity. We diagnose these limits by combining a thorough statistical method and detailed image simulations. - Highlights: • Limited size and beam sensitivity of nano-particles challenge their quantification. • Keeping the electron dose to a minimum is therefore important. • Reliability of quantitative ADF STEM for atom-counting is demonstrated. • Limits for single atom sensitivity are discussed. • Limits are diagnosed by combining simulations and a statistical method.

  4. Dose limited reliability of quantitative annular dark field scanning transmission electron microscopy for nano-particle atom-counting

    International Nuclear Information System (INIS)

    Quantitative annular dark field scanning transmission electron microscopy (ADF STEM) has become a powerful technique to characterise nano-particles on an atomic scale. Because of their limited size and beam sensitivity, the atomic structure of such particles may become extremely challenging to determine. Therefore keeping the incoming electron dose to a minimum is important. However, this may reduce the reliability of quantitative ADF STEM which will here be demonstrated for nano-particle atom-counting. Based on experimental ADF STEM images of a real industrial catalyst, we discuss the limits for counting the number of atoms in a projected atomic column with single atom sensitivity. We diagnose these limits by combining a thorough statistical method and detailed image simulations. - Highlights: • Limited size and beam sensitivity of nano-particles challenge their quantification. • Keeping the electron dose to a minimum is therefore important. • Reliability of quantitative ADF STEM for atom-counting is demonstrated. • Limits for single atom sensitivity are discussed. • Limits are diagnosed by combining simulations and a statistical method

  5. A QSPR Study of Sweetness Potency Using the CODESSA Program

    OpenAIRE

    Alan R. Katritzky; Petrukhin, Ruslan; Perumal, Subbu; Karelson, Mati; Prakash, Indra; Desai, Nitin

    2002-01-01

    A total of 397 natural and artificial comprehensively referenced sweeteners were classified by their structures into nine sets. The sweetness potencies were correlated with quantum Chemical and other molecular descriptors using the heuristic and the best multi-linear regression methods of the CODESSA software package. QSPR models (two-parameter unless otherwise indicated) emerged for each subclass of sweeteners with R2 values of 0.835 for 47 aldoximes, 0.959 for 8 acesulfamates, 0.919 for 9 s...

  6. Longitudinal trends of total white blood cell and differential white blood cell counts of atomic bomb survivors

    International Nuclear Information System (INIS)

    In studying the late health effects of atomic-bomb (A-bomb) survivors, earlier findings were that white blood cell (WBC) count increased with radiation dose in cross-sectional studies. However, a persistent effect of radiation on WBC count and other risk factors has yet to be confirmed. The objectives of the present study were to examine the longitudinal relationship between A-bomb radiation dose and WBC and differential WBC counts among A-bomb survivors and to investigate the potential confounding risk factors (such as age at exposure and smoking status) as well as modification of the radiation dose-response. A total of 7,562 A-bomb survivors in Hiroshima and Nagasaki were included in this study from 1964-2004. A linear mixed model was applied using the repeated WBC measurements. During the study period, a secular downward trend of WBC count was observed. Radiation exposure was a significant risk factor for elevated WBC and differential WBC counts over time. A significant increase of WBC counts among survivors with high radiation dose (>2 Gy) was detected in men exposed below the age of 20 and in women regardless of age at exposure. Effects on WBC of low dose radiation remain unclear, however. Cigarette smoking produced the most pronounced effect on WBC counts and its impact was much larger than that of radiation exposure. (author)

  7. Longitudinal trends of total white blood cell and differential white blood cell counts of atomic bomb survivors.

    Science.gov (United States)

    Hsu, Wan-Ling; Tatsukawa, Yoshimi; Neriishi, Kazuo; Yamada, Michiko; Cologne, John; Fujiwara, Saeko

    2010-01-01

    In studying the late health effects of atomic-bomb (A-bomb) survivors, earlier findings were that white blood cell (WBC) count increased with radiation dose in cross-sectional studies. However, a persistent effect of radiation on WBC count and other risk factors has yet to be confirmed. The objectives of the present study were 1) to examine the longitudinal relationship between A-bomb radiation dose and WBC and differential WBC counts among A-bomb survivors and 2) to investigate the potential confounding risk factors (such as age at exposure and smoking status) as well as modification of the radiation dose-response. A total of 7,562 A-bomb survivors in Hiroshima and Nagasaki were included in this study from 1964-2004. A linear mixed model was applied using the repeated WBC measurements. During the study period, a secular downward trend of WBC count was observed. Radiation exposure was a significant risk factor for elevated WBC and differential WBC counts over time. A significant increase of WBC counts among survivors with high radiation dose (> 2 Gy) was detected in men exposed below the age of 20 and in women regardless of age at exposure. Effects on WBC of low dose radiation remain unclear, however. Cigarette smoking produced the most pronounced effect on WBC counts and its impact was much larger than that of radiation exposure. PMID:20543527

  8. MDF - A New QSPR/QSAR Molecular Descriptors Family

    OpenAIRE

    Jäntschi, Lorentz

    2004-01-01

    MotivationIn the present are many QSAR/QSPR models, based on varied considerations, from mathematical through topological and geometrical to 3D molecular geometry approaches.IdeaThe idea is to create a unitary approach, based on a minimal set of well-known truths, capable to generate an efficient model of property behavior depending on molecular structure.MethodFirst step in order to reach the proposed goal is to create a huge family of molecular descriptors starting from molecular structure ...

  9. Atoms

    International Nuclear Information System (INIS)

    Completed by recent contributions on various topics (atoms and the Brownian motion, the career of Jean Perrin, the evolution of atomic physics since Jean Perrin, relationship between scientific atomism and philosophical atomism), this book is a reprint of a book published at the beginning of the twentieth century in which the author addressed the relationship between atomic theory and chemistry (molecules, atoms, the Avogadro hypothesis, molecule structures, solutes, upper limits of molecular quantities), molecular agitation (molecule velocity, molecule rotation or vibration, molecular free range), the Brownian motion and emulsions (history and general features, statistical equilibrium of emulsions), the laws of the Brownian motion (Einstein's theory, experimental control), fluctuations (the theory of Smoluchowski), light and quanta (black body, extension of quantum theory), the electricity atom, the atom genesis and destruction (transmutations, atom counting)

  10. Influence of atomic and nuclear constants on the counting efficiency for 55Fe in liquid scintillators

    International Nuclear Information System (INIS)

    In this paper one considers the influence of the different parameters on the determination of the uncertainty of the detection efficiency for 55Fe when the counting technique of liquid scintillation is applied. The following parameters are considered: the relative probabilities of X and Auger emission so as their corresponding energies, the fluorescence yields WK and WL, and the non-interaction probabilities of the emitted X photons. (Author) 11 refs

  11. Configurable memory system and method for providing atomic counting operations in a memory device

    Science.gov (United States)

    Bellofatto, Ralph E.; Gara, Alan G.; Giampapa, Mark E.; Ohmacht, Martin

    2010-09-14

    A memory system and method for providing atomic memory-based counter operations to operating systems and applications that make most efficient use of counter-backing memory and virtual and physical address space, while simplifying operating system memory management, and enabling the counter-backing memory to be used for purposes other than counter-backing storage when desired. The encoding and address decoding enabled by the invention provides all this functionality through a combination of software and hardware.

  12. Radial Basis Function Neural Networks Based QSPR for the Prediction of log P

    Institute of Scientific and Technical Information of China (English)

    YAO,Xiao-Jun(姚小军); LIU,Man-Cang(刘满仓); ZHANG,Xiao-Yun(张晓昀); ZHANG,Rui-Sheng(张瑞生); HU,Zhi-De(胡之德); FAN,Bo-Tao(范波涛)

    2002-01-01

    Quantitative structure-property relatioonship (QSPR) method is used to study the correlation models between the structures of a set of diverse organic compounds and their log P. Molecular descriptors calculated from structure alone are used to describe the molecular structures. A subset of the calculated descriptors, selected using forward stepwise regression, is used in the QSPR models development. Multiple linear regression (MLR)and radial basis function neural networks (RBFNNs) are urilized to construct the linear and non-linear correlation model,respectively. The optimal QSPR model developedis based on a 7-17-1 RBFNNs architecture using seven calculated molecular descriptors. The root mean square errorsin predictions for the training, predicting and overall data sets are 0.284, 0.327 and 0.291 log P units, respectively.

  13. Radial Basis Function Neural Networks Based QSPR for the Prediction of log P

    Institute of Scientific and Technical Information of China (English)

    姚小军; 范波涛; 等

    2002-01-01

    Quantitative structure-property relationship(QSPR) method is used to study the correlation models between the structures of a set of diverse organic compounds and their log P.Molecular descriptors calculated from strucure alone are used to describe the molecular structures.A subset of the calcualted descriptors,selected using forward stepwise regression,is used in the QSPR models development.Multiple linear regression (MLR) and radial basis function neural networks (RBFNNs) are utilied to construct the linear and non-linear correlation model,respectively,The optimal QSPR model developed is based on a 7-17-1 RBFNNs architecture using sever calculated molecular descriptors .The root mean square errors in predictions for the training,predicting and overall data sets are 0.284,0.327 and 0.291 log P units respectively.

  14. Standards, intercomparisons and performance evaluations for low-level and environmental radionuclide mass spectrometry and atom counting

    International Nuclear Information System (INIS)

    Because of the demand for higher sensitivity radionuclide measurements, atom counting technology will become an increasingly used modality in geo-and bio-studies, and process control operations. It is anticipated that requests, intercomparisons and performance evaluations services will surge in near future. In anticipation of such requests, the state-of-the-art needed to be assessed for proactive planning purposes. The results of a workshop focused on these issues indicated that there are several ongoing standards, intercomparisons and performance evaluations thrusts which are expected to expand in the future. Furthermore, new projects were planned and the Council on Ionizing Radiation Measurements and Standards (Public and Environmental Radiation Protection subcommittee) ws proposed as an information coordinator. (author)

  15. Predicting the reaction rate constants of micropollutants with hydroxyl radicals in water using QSPR modeling.

    Science.gov (United States)

    Jin, Xiaohui; Peldszus, Sigrid; Huck, Peter M

    2015-11-01

    Quantitative structure-property relationship (QSPR) models which predict hydroxyl radical rate constants (kOH) for a wide range of emerging micropollutants are a cost effective approach to assess the susceptibility of these contaminants to advanced oxidation processes (AOPs). A QSPR model for the prediction of kOH of emerging micropollutants from their physico-chemical properties was developed with special attention to model validation, applicability domain and mechanistic interpretation. In this study, 118 emerging micropollutants including those experimentally determined by the author and data collected from the literature, were randomly divided into the training set (n=89) and validation set (n=29). 951 DRAGON molecular descriptors were calculated for model development. The QSPR model was calibrated by applying forward multiple linear regression to the training set. As a result, 7 DRAGON descriptors were found to be important in predicting the kOH values which related to the electronegativity, polarizability, and double bonds, etc. of the compounds. With outliers identified and removed, the final model fits the training set very well and shows good robustness and internal predictivity. The model was then externally validated with the validation set showing good predictive power. The applicability domain of the model was also assessed using the Williams plot approach. Overall, the developed QSPR model provides a valuable tool for an initial assessment of the susceptibility of micropollutants to AOPs. PMID:26005810

  16. Improvement of the signal-to-noise ratio of laser-induced-fluorescence photon-counting signals of single-atoms magneto-optical trap

    International Nuclear Information System (INIS)

    Employing grating extended-cavity diode lasers as the cooling/trapping and repumping lasers for preparing and manipulating single atoms, we have implemented a large-magnetic-gradient caesium magneto-optical trap (MOT). To detect and evaluate single caesium atoms trapped in MOT, laser-induced-fluorescence (LIF) photons of trapped atoms driven by MOT lasers are collected and counted by an avalanched photodiode worked in photon-counting mode. The dependences of LIF photon-counting signals of single atoms on a cooling laser's intensity, frequency detuning and frequency fluctuation are analysed and investigated. Remarkable improvement of the signal-to-noise ratio of LIF photon-counting signals is achieved by optimizing the cooling laser's intensity and frequency detuning and using the modulation-free polarization spectroscopic technique with feedback to both the slow channel (piezoelectric transducer channel with typical bandwidth of ∼2 kHz in the grating extended cavity) and the fast channel (current modulation channel with typical bandwidth of ∼200 kHz in the current driver).

  17. QSPR Models for Chromatographic Retention of Some Azoles with Physicochemical Properties

    International Nuclear Information System (INIS)

    This work deals with 24 substances composed of nitrogen-containing heterocycles. The relationships between the chromatographic retention factor (k) and those physicochemical properties which are relevant in quantitative structure-properties relationship (QSPR) studies, such as the polarizability (α), molar refractivity (MR), lipophilicity (logP), dipole moment (μ), total energy (Etot), heat of formation (ΔHf), molecular surface area (SM), and binding energy (Eb), were investigated. The accuracy of the simple linear regressions between the chromatographic retention and the descriptors for all of the compounds was satisfactory (correlation coefficient, 0.8 ≤ r ≤ 1.0). The QSPR models of these nitrogen-containing heterocyclic compounds could be predicted with a multiple linear regression equation having the statistical index, r = 1.000. This work demonstrated the successful application of the multiple linear approaches through the development of accurate predictive equations for retention factors in liquid chromatography

  18. QSPR study of molar diamagnetic susceptibility of diverse organic compounds using multiple linear regression analysis

    OpenAIRE

    *S. Saaidpour; S. A. Zarei; F. Nasri

    2012-01-01

    The multiple linear regression (MLR) was used to build the linear quantitative structure-property relationship (QSPR) model for the prediction of the molar diamagnetic susceptibility (χm) for 140 diverse organic compounds using the three significant descriptors calculated from the molecular structures alone and selected by stepwise regression method. Stepwise regression was employed to develop a regression equation based on 100 training compounds, and predictive ability was tested on 40 compo...

  19. A QSPR STUDY OF NORMAL BOILING POINT OF ORGANIC COMPOUNDS (ALIPHATIC ALKANES) USING MOLECULAR DESCRIPTORS

    OpenAIRE

    B. Souyei; M. Korichi

    2013-01-01

    A quantitative structure–property relationship (QSPR) study is carried out to develop correlations that relate the molecular structures of organic compounds (Aliphatic Alkanes) to their normal boiling point (NBP) and two correlations were proposed for constitutionals and connectivity indices Models. The correlations are simple in application with good accuracy, which provide an easy, direct and relatively accurate way to calculate NBP. Such calculation gives us a model that gives results in r...

  20. Predictive QSPR analysis of corrosion inhibitors for super 13% Cr steel in hydrochloric acid

    OpenAIRE

    S. P. Cardoso; J. A. C. P. Gomes; L. E. P. Borges; E. Hollauer

    2007-01-01

    An experimental and theoretical study on the inhibition corrosion efficiencies of twenty three compounds in hydrochloric acid (15% w/v) on 13% Cr modified stainless steel (martensitic) has been carried out. This inhibitor set includes amines, thiourea derivatives and acetylenic alcohols. Experimental weight losses at 60ºC were correlated with group and quantum AM1 descriptors obtained from QSPR analysis. Such data, for a large set of molecules, offer a unique opportunity for searching for cor...

  1. Calculations of Hyperpolarizabilities for Para-disubstituted Benzenes with the QSPR

    Institute of Scientific and Technical Information of China (English)

    Xian Dong ZENG; Xuan XU; Bing Feng WANG; Bing Can WANG

    2004-01-01

    A quantitative structure-property relationship (QSPR) was made for the prediction of the hyperpolarizabilities(β) of para-disubstituted benzenes with the nonlinear optical properties, and the βcal2 calculated by this model accorded better with the experimental values (βexpt) compared with theβcal1 calculated at the CPHF/6-31G*//HF/STO-3G level of theory, especially whenβ was big.

  2. Prediction of the thermal decomposition of organic peroxides by validated QSPR models

    International Nuclear Information System (INIS)

    Highlights: • QSPR models were developed for thermal stability of organic peroxides. • Two accurate MLR models were exhibited based on quantum chemical descriptors. • Performances were evaluated by a series of internal and external validations. • The new QSPR models satisfied all OCDE principles of validation for regulatory use. - Abstract: Organic peroxides are unstable chemicals which can easily decompose and may lead to explosion. Such a process can be characterized by physico-chemical parameters such as heat and temperature of decomposition, whose determination is crucial to manage related hazards. These thermal stability properties are also required within many regulatory frameworks related to chemicals in order to assess their hazardous properties. In this work, new quantitative structure–property relationships (QSPR) models were developed to predict accurately the thermal stability of organic peroxides from their molecular structure respecting the OECD guidelines for regulatory acceptability of QSPRs. Based on the acquisition of 38 reference experimental data using DSC (differential scanning calorimetry) apparatus in homogenous experimental conditions, multi-linear models were derived for the prediction of the decomposition heat and the onset temperature using different types of molecular descriptors. Models were tested by internal and external validation tests and their applicability domains were defined and analyzed. Being rigorously validated, they presented the best performances in terms of fitting, robustness and predictive power and the descriptors used in these models were linked to the peroxide bond whose breaking represents the main decomposition mechanism of organic peroxides

  3. Ant colony optimization as a descriptor selection in QSPR modeling for prediction of λmax of azo dyes

    Institute of Scientific and Technical Information of China (English)

    Morteza Atabati; Farzaneh Khandani

    2012-01-01

    A quantitative structure-property relationship (QSPR) study was suggested for the prediction of λmax of azo dyes.After optimization of 3D geometry of structures,different descriptors were calculated by the HyperChem and Dragon softwares.A major problem of QSPR is the high dimensionality of the descriptor space; therefore,descriptor selection is the most important step for these studies.In this paper,an ant colony optimization (ACO) algorithm was proposed to select the best descriptors.

  4. Prediction of standard chemical exergy by a three descriptors QSPR model

    International Nuclear Information System (INIS)

    A new quantitative structure-property relationship (QSPR) three parameter correlation (R 2 = 0.9977) of standard chemical exergy for a diverse set of 134 organic substances was developed by application of a genetic algorithm search. The descriptors are all calculated directly from the molecular structure, and the approach given is applicable, in principle, to all organic substances of regular structure. The application of the genetic algorithm in comparison with stepwise multi-variate linear regression (MLR) shows some advantages in required time for solving and in precision

  5. A QSPR STUDY OF NORMAL BOILING POINT OF ORGANIC COMPOUNDS (ALIPHATIC ALKANES USING MOLECULAR DESCRIPTORS

    Directory of Open Access Journals (Sweden)

    B. Souyei

    2013-12-01

    Full Text Available A quantitative structure–property relationship (QSPR study is carried out to develop correlations that relate the molecular structures of organic compounds (Aliphatic Alkanes to their normal boiling point (NBP and two correlations were proposed for constitutionals and connectivity indices Models. The correlations are simple in application with good accuracy, which provide an easy, direct and relatively accurate way to calculate NBP. Such calculation gives us a model that gives results in remarkable correlations with the descriptors of blokes constitutionals (CON, and connectivity indices (CI (R2 = 0.950, δ = 0.766 (R2 = 0.969, δ = 0.782 respectively.

  6. The Interplay between QSAR/QSPR Studiesand Partial Order Ranking and Formal Concept Analyses

    Directory of Open Access Journals (Sweden)

    Lars Carlsen

    2009-04-01

    Full Text Available The often observed scarcity of physical-chemical and well as toxicological data hampers the assessment of potentially hazardous chemicals released to the environment. In such cases Quantitative Structure-Activity Relationships/Quantitative Structure-Property Relationships (QSAR/QSPR constitute an obvious alternative for rapidly, effectively and inexpensively generatng missing experimental values. However, typically further treatment of the data appears necessary, e.g., to elucidate the possible relations between the single compounds as well as implications and associations between the various parameters used for the combined characterization of the compounds under investigation. In the present paper the application of QSAR/QSPR in combination with Partial Order Ranking (POR methodologies will be reviewed and new aspects using Formal Concept Analysis (FCA will be introduced. Where POR constitutes an attractive method for, e.g., prioritizing a series of chemical substances based on a simultaneous inclusion of a range of parameters, FCA gives important information on the implications associations between the parameters. The combined approach thus constitutes an attractive method to a preliminary assessment of the impact on environmental and human health by primary pollutants or possibly by a primary pollutant well as a possible suite of transformation subsequent products that may be both persistent in and bioaccumulating and toxic.The present review focus on the environmental – and human health impact by residuals of the rocket fuel 1,1-dimethyl- hydrazine (heptyl and its transformation products as an illustrative example.

  7. QSPR models based on molecular mechanics and quantum chemical calculations. 2. Thermodynamic properties of alkanes, alcohols, polyols, and ethers

    DEFF Research Database (Denmark)

    Dyekjær, Jane Dannow; Jonsdottir, Svava Osk

    2003-01-01

    Quantitative Structure-Property Relationship (QSPR) models for prediction of various thermodynamic properties of simple organic compounds have been developed. A number of new descriptors are proposed and used alongside with descriptors available within the Codessa program. An important feature in...

  8. Atoms

    Institute of Scientific and Technical Information of China (English)

    刘洪毓

    2007-01-01

    Atoms(原子)are all around us.They are something like the bricks (砖块)of which everything is made. The size of an atom is very,very small.In just one grain of salt are held millions of atoms. Atoms are very important.The way one object acts depends on what

  9. Preliminary description of a dedicated commercial ultra-sensitive mass spectrometer for direct atom counting of 14C

    International Nuclear Information System (INIS)

    A description is presented of a commercial, tandem-accelerator centered secondary ion double mass spectrometer dedicated to 14C/13C/12C ratio measurements. Some design philosophy of the instrument is presented and the performance is described. A scanning cesium ion source with primary beam diameters between 100 to 200 micrometers is used to produce C- beam intensities of 10 to 20μA with the intensities remaining constant to better than 0.1% per minute after the source stabilizes. For recent carbon, these currents correspond to 14C count rates from the ion source of 60 to 120 particles per second. Resolution of the first mass defining system, M/ΔM, is greater than 120 with the capability of rapid mass switching between isotopes. The measured isotopic ratios at the ion source for carbon are constant to better than 0.25%. The virtues of the 3MV parallel-fed Cockroft-Walton accelerator supply are presented. At the operating voltage of 2.5MV, the stability is better than 1:4000 with a terminal ripple 13C3+ and 12C3+ ions which originate from mass-14 molecular ions are measured to be 3.6mm away from the beam axis and so can be completely eliminated by the slits. Isotopic ratios have been measured beyond these slits, and it is shown that these ratios are constant to better than half a percent using recent samples. The final strong focusing magnet has a rejection ratio for unwanted carbon ions greater than 107

  10. Linear and Nonlinear QSPR Models for Predicting Thermal Stabilities of Nitroaromatic Compounds

    Institute of Scientific and Technical Information of China (English)

    SANG Peng; ZOU Jian-wei; XU Lin; ZHOU Peng

    2011-01-01

    Quantitative structure-property relationships(QSPRs) have been developed to predict the thermal stability for a set of 22 nitroaromatic compounds by means of the theoretical descriptors derived from electrostatic potentials on molecular surface.Several techniques,including partial least squares regression(PLS),least-squares support vector machine(LSSVM) and Gaussian process(GP) have been utilized to establish the relationships between the structural descriptor and the decomposition enthalpy.The nonlinear LSSVM and GP models have proven to own a better predictive ability than the linear PLS method.Moreover,owing to its ability to handle both linear- and nonlinear-hybrid relationship,GP gives a stronger fitting ability and a better predictive power than LSSVM,and therefore could be well applied to developing QSPR models for the thermal stability of nitroaromatic explosives.

  11. Quantitative Structure-Property Relationship (QSPR) Models for a Local Quantum Descriptor: Investigation of the 4- and 3-Substituted-Cinnamic Acid Esterification.

    Science.gov (United States)

    Rodrigues-Santos, Cláudio E; Echevarria, Aurea; Sant'Anna, Carlos M R; Bitencourt, Thiago B; Nascimento, Maria G; Bauerfeldt, Glauco F

    2015-01-01

    In this work, the theoretical description of the 4- and 3-substituted-cinnamic acid esterification with different electron donating and electron withdrawing groups was performed at the B3LYP and M06-2X levels, as a two-step process: the O-protonation and the nucleophile attack by ethanol. In parallel, an experimental work devoted to the synthesis and characterization of the substituted-cinnamate esters has also been performed. In order to quantify the substituents effects, quantitative structure-property relationship (QSPR) models based on the atomic charges, Fukui functions and the Frontier Effective-for-Reaction Molecular Orbitals (FERMO) energies were investigated. In fact, the Fukui functions, ƒ⁺C and ƒ(-)O, indicated poor correlations for each individual step, and in contrast with the general literature, the O-protonation step is affected both by the FERMO energies and the O-charges of the carbonyl group. Since the process was shown to not be totally described by either charge- or frontier-orbitals, it is proposed to be frontier-charge-miscere controlled. Moreover, the observed trend for the experimental reaction yields suggests that the electron withdrawing groups favor the reaction and the same was observed for Step 2, which can thus be pointed out as the determining step. PMID:26402661

  12. Quantitative Structure–Property Relationship (QSPR Models for a Local Quantum Descriptor: Investigation of the 4- and 3-Substituted-Cinnamic Acid Esterification

    Directory of Open Access Journals (Sweden)

    Cláudio E. Rodrigues-Santos

    2015-09-01

    Full Text Available In this work, the theoretical description of the 4- and 3-substituted-cinnamic acid esterification with different electron donating and electron withdrawing groups was performed at the B3LYP and M06-2X levels, as a two-step process: the O-protonation and the nucleophile attack by ethanol. In parallel, an experimental work devoted to the synthesis and characterization of the substituted-cinnamate esters has also been performed. In order to quantify the substituents effects, quantitative structure–property relationship (QSPR models based on the atomic charges, Fukui functions and the Frontier Effective-for-Reaction Molecular Orbitals (FERMO energies were investigated. In fact, the Fukui functions, ƒ+C and ƒ−O, indicated poor correlations for each individual step, and in contrast with the general literature, the O-protonation step is affected both by the FERMO energies and the O-charges of the carbonyl group. Since the process was shown to not be totally described by either charge- or frontier-orbitals, it is proposed to be frontier-charge-miscere controlled. Moreover, the observed trend for the experimental reaction yields suggests that the electron withdrawing groups favor the reaction and the same was observed for Step 2, which can thus be pointed out as the determining step.

  13. QSPR modeling of soil sorption coefficients (K(OC)) of pesticides using SPA-ANN and SPA-MLR.

    Science.gov (United States)

    Goudarzi, Nasser; Goodarzi, Mohammad; Araujo, Mario Cesar Ugulino; Galvão, Roberto Kawakami Harrop

    2009-08-12

    A quantitative structure-property relationship (QSPR) study was conducted to predict the adsorption coefficients of some pesticides. The successive projection algorithm feature selection (SPA) strategy was used as descriptor selection and model development method. Modeling of the relationship between selected molecular descriptors and adsorption coefficient data was achieved by linear (multiple linear regression; MLR) and nonlinear (artificial neural network; ANN) methods. The QSPR models were validated by cross-validation as well as application of the models to predict the K(OC) of external set compounds, which did not contribute to model development steps. Both linear and nonlinear methods provided accurate predictions, although more accurate results were obtained by the ANN model. The root-mean-square errors of test set obtained by MLR and ANN models were 0.3705 and 0.2888, respectively. PMID:19722589

  14. Cell counting.

    Science.gov (United States)

    Phelan, M C; Lawler, G

    2001-05-01

    This unit presents protocols for counting cells using either a hemacytometer or electronically using a Coulter counter. Cell counting with a hemacytometer permits effective discrimination of live from dead cells using trypan blue exclusion. In addition, the procedure is less subject to errors arising from cell clumping or size heterogeneity. Counting cells is more quickly and easily performed using an electronic counter, but live-dead discrimination is unreliable. Cell populations containing large numbers of dead cells and/or cell clumps are difficult to count accurately. In addition, electronic counting requires resetting of the instrument for cell populations of different sizes; heterogeneous populations can give rise to inaccurate counts, and resting and activated cells may require counting at separate settings. In general, electronic cell counting is best performed on fresh peripheral blood cells. PMID:18770655

  15. Seal Counts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Database of seal counts from aerial photography. Counts by image, site, species, and date are stored in the database along with information on entanglements and...

  16. Counting carbohydrates

    Science.gov (United States)

    Carb counting; Carbohydrate-controlled diet; Diabetic diet; Diabetes-counting carbohydrates ... goal is not to limit carbohydrates in the diet completely, but to make ... with diabetes can better control their blood sugar if they ...

  17. Sherlock Holmes counts the atoms

    Science.gov (United States)

    Tuniz, C.; Zoppi, U.; Hotchkis, M. A. C.

    2004-01-01

    Modern forensic science has to deal not only with homicides and other traditional crimes but also with more global threats such as smuggling of nuclear materials, clandestine production of weapons of mass destruction, stockpiling of illicit drugs by state-controlled groups and war crimes. Forensic applications have always benefited from the use of advanced analytical tools that can characterise materials found at crime scenes. In this paper we will discuss the use of accelerator mass spectrometry as an ultra sensitive tool for the crime labs of the third millennium.

  18. Sherlock Holmes counts the atoms

    International Nuclear Information System (INIS)

    Modern forensic science has to deal not only with homicides and other traditional crimes but also with more global threats such as smuggling of nuclear materials, clandestine production of weapons of mass destruction, stockpiling of illicit drugs by state-controlled groups and war crimes. Forensic applications have always benefited from the use of advanced analytical tools that can characterise materials found at crime scenes. In this paper we will discuss the use of accelerator mass spectrometry as an ultra sensitive tool for the crime labs of the third millennium

  19. QSPR prediction of the hydroxyl radical rate constant of water contaminants.

    Science.gov (United States)

    Borhani, Tohid Nejad Ghaffar; Saniedanesh, Mohammadhossein; Bagheri, Mehdi; Lim, Jeng Shiun

    2016-07-01

    In advanced oxidation processes (AOPs), the aqueous hydroxyl radical (HO) acts as a strong oxidant to react with organic contaminants. The hydroxyl radical rate constant (kHO) is important for evaluating and modelling of the AOPs. In this study, quantitative structure-property relationship (QSPR) method is applied to model the hydroxyl radical rate constant for a diverse dataset of 457 water contaminants from 27 various chemical classes. The constricted binary particle swarm optimization and multiple-linear regression (BPSO-MLR) are used to obtain the best model with eight theoretical descriptors. An optimized feed forward neural network (FFNN) is developed to investigate the complex performance of the selected molecular parameters with kHO. Although the FFNN prediction results are more accurate than those obtained using BPSO-MLR, the application of the latter is much more convenient. Various internal and external validation techniques indicate that the obtained models could predict the logarithmic hydroxyl radical rate constants of a large number of water contaminants with less than 4% absolute relative error. Finally, the above-mentioned proposed models are compared to those reported earlier and the structural factors contributing to the AOP degradation efficiency are discussed. PMID:27124124

  20. Counting cormorants

    DEFF Research Database (Denmark)

    Bregnballe, Thomas; Carss, David N; Lorentsen, Svein-Håkon;

    2013-01-01

    This chapter focuses on Cormorant population counts for both summer (i.e. breeding) and winter (i.e. migration, winter roosts) seasons. It also explains differences in the data collected from undertaking ‘day’ versus ‘roost’ counts, gives some definitions of the term ‘numbers’, and presents two e...

  1. Maximum Topological Distances Based Indices as Molecular Descriptors for QSPR. 4. Modeling the Enthalpy of Formation of Hydrocarbons from Elements

    Directory of Open Access Journals (Sweden)

    Andrey A. Toropov

    2001-06-01

    Full Text Available The enthalpy of formation of a set of 60 hydroarbons is calculated on the basis of topological descriptors defined from the distance and detour matrices within the realm of the QSAR/QSPR theory. Linear and non-linear polynomials fittings are made and results show the need to resort to higher-order regression equations in order to get better concordances between theoretical results and experimental available data. Besides, topological indices computed from maximum order distances seems to yield rather satisfactory predictions of heats of formation for hydrocarbons.

  2. Multiplicity Counting

    Energy Technology Data Exchange (ETDEWEB)

    Geist, William H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-01

    This set of slides begins by giving background and a review of neutron counting; three attributes of a verification item are discussed: 240Pueff mass; α, the ratio of (α,n) neutrons to spontaneous fission neutrons; and leakage multiplication. It then takes up neutron detector systems – theory & concepts (coincidence counting, moderation, die-away time); detector systems – some important details (deadtime, corrections); introduction to multiplicity counting; multiplicity electronics and example distributions; singles, doubles, and triples from measured multiplicity distributions; and the point model: multiplicity mathematics.

  3. Star counts

    International Nuclear Information System (INIS)

    The number of stars counted along a particular line of sight depends on the spatial distribution of stars, the luminosity function, and the absorption. Thus star count programs designed to constrain or determine one or more of these functions. Early efforts to understand the structure of our Galaxy, including the fundamentals of stellar statistics, were largely based on work that involved star counts. Since then a growing appreciation has developed for the variety of forms the density function and the luminosity function can take, especially the recognition of different stellar populations, each with different density and luminosity functions. In the simplest formulation two distinct populations are considered: disk and halo. This suggests two distinct formation histories, but uncertainty in the picture remains. (Auth.)

  4. Understanding Blood Counts

    Science.gov (United States)

    ... Lab and Imaging Tests Understanding Blood Counts Understanding Blood Counts Understanding Blood Counts SHARE: Print Glossary Blood cell counts give ... your blood that's occupied by red cells. Normal Blood Counts Normal blood counts fall within a range ...

  5. Testing the Agreement/Tense Omission Model: Why the Data on Children's Use of Non-Nominative 3psg Subjects Count against the ATOM

    Science.gov (United States)

    Pine, Julian M.; Rowland, Caroline F.; Lieven, Elena V. M.; Theakston, Anna L.

    2005-01-01

    One of the most influential recent accounts of pronoun case-marking errors in young children's speech is Schutze & Wexler's (1996) Agreement/Tense Omission Model (ATOM). The ATOM predicts that the rate of agreeing verbs with non-nominative subjects will be so low that such errors can be reasonably disregarded as noise in the data. The present…

  6. Profile counting

    International Nuclear Information System (INIS)

    In ''profile counting'', a counter is moved progressively along the whole length of the body, and is so collimated that, at each position, it records the radioisotope content of the whole width of the body, but of only a short section of its length. If the counting rate at each position is plotted against the distance of the counter from the vertex of the head, the ''profile'' so obtained gives a rapid and quantitative measure of the radioisotope distribution throughout the body. When a suitable isotope is selectively concentrated in certain organs or tissues of the body, the profile will show peaks indicative of the sites and extent of such concentration, the organs concerned being identified by two-dimensional mapping, and profile counts continued to follow the turnover or changes of concentration in these organs. This technique has been used in the study of I131 concentration and metabolism in thyroid carcinomata, and its value in the management of the radioiodine treatment of such tumours will be discussed. It has also been used in examining the distribution of labelled thyroxine and triiodothyronine after intravenous administration, and of yttrium-90 oxide particles after intrapulmonary artery injection; and of other isotopes by gamma radiation or bremsstrahlung. The method gives a clinically convenient simplification of whole body mapping which lends itself particularly to the quantitative comparison of isotope distribution at different intervals after a radioisotope dose, or after successive doses. (author)

  7. A Quantitative Structure-Property Relationship (QSPR Study of Aliphatic Alcohols by the Method of Dividing the Molecular Structure into Substructure

    Directory of Open Access Journals (Sweden)

    Bin Cheng

    2011-04-01

    Full Text Available A quantitative structure–property relationship (QSPR analysis of aliphatic alcohols is presented. Four physicochemical properties were studied: boiling point (BP, n-octanol–water partition coefficient (lg POW, water solubility (lg W and the chromatographic retention indices (RI on different polar stationary phases. In order to investigate the quantitative structure–property relationship of aliphatic alcohols, the molecular structure ROH is divided into two parts, R and OH to generate structural parameter. It was proposed that the property is affected by three main factors for aliphatic alcohols, alkyl group R, substituted group OH, and interaction between R and OH. On the basis of the polarizability effect index (PEI, previously developed by Cao, the novel molecular polarizability effect index (MPEI combined with odd-even index (OEI, the sum eigenvalues of bond-connecting matrix (SX1CH previously developed in our team, were used to predict the property of aliphatic alcohols. The sets of molecular descriptors were derived directly from the structure of the compounds based on graph theory. QSPR models were generated using only calculated descriptors and multiple linear regression techniques. These QSPR models showed high values of multiple correlation coefficient (R > 0.99 and Fisher-ratio statistics. The leave-one-out cross-validation demonstrated the final models to be statistically significant and reliable.

  8. The diode pump: its application to nuclear particle counting and to the detection of rapid neutronic power excursions in atomic piles (1962)

    International Nuclear Information System (INIS)

    This work deals in particular with three applications of an electronic device whose principle is based on that of the diode pump. 1- Linear response circuit 2- Logarithmic response circuit 3- Detection of neutronic power excursions in atomic piles using a circuit or a combination of several circuits of the linear response type. Each of the applications has been studied theoretically and experimentally. Finally, the detection of rapid power excursions is extensively discussed with reference to the many methods available, emphasis being laid on the rapidity of the electronic response. (author)

  9. A comparative study of natural 40K content estimated through whole body counting and dietary intake around Narora Atomic Power Station

    International Nuclear Information System (INIS)

    773 radiation workers at NAPS, aged 20 to 59 years, were monitored using Shadow Shield Whole Body Counting System having NaI (Tl) crystal coupled with NETS-3 1 K Multi Channel Analyser (MCA) to determine the 40K activity in the body and assess internal dose due to naturally occurring 40K. The data have been segregated to make analyses for vegetarian and non-vegetarian. The average annual dose from 40K for the subjects is evaluated as 156.4 ± 36.1 mSv. Natural 40K content in 463 environmental samples collected from Narora environ estimated using NaI(Tl) well type detector coupled with 1 K NETS-3 Multichannel analyser (MCA). Assessment of daily intake of natural 40K has been estimated from average daily intake of dietary items and the associated 40K activity. It works out to be 67.17 ± 16.28 Bq/d and that obtained through analysis of complete meal samples was 73.22 ± 9.78 Bq/ d. The average annual dose to a member of public of this region due to natural 40K through ingestion route works out to be 152.12 ± 36.83 mSv/year. (author)

  10. Measurement of activity coefficients at infinite dilution for hydrocarbons in imidazolium-based ionic liquids and QSPR model

    Institute of Scientific and Technical Information of China (English)

    ZHU Jiqin; YU Yanmei; CHEN Jian; FEI Weiyang

    2007-01-01

    The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficients γ∞ at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation.In fact,the measurement of γ∞ by gas-liquid chromatography is a speedy and costsaving method.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylbenzenes,styrene,in 1-allyl-3-methylimidazolium tetrafluoroborate ([AMIM][BF4]) and 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM][PF6]), 1-isobutenyl-3-methylimidazolium tetrafluoroborate ([MPMIM][BF4]) and [MPMIM][BF4]-AgBF4 have been determined by gas-liquid chromatography using ionic liquids as stationary phase.The measurements were carried out at different temperatures from 298 to 318 K.The separating effects of these ionic liquids for alkanes/hexane,aliphatic hydrocarbons/benzene and hexene isomers have been discussed.The hydrophobic parameter,dipole element,frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method.The quantitative relations among the computed structure parameters and activity coefficients at infinite dilution were also developed.The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.

  11. QSPR Models for Predicting Log Pliver Values for Volatile Organic Compounds Combining Statistical Methods and Domain Knowledge

    Directory of Open Access Journals (Sweden)

    Mónica F. Díaz

    2012-12-01

    Full Text Available Volatile organic compounds (VOCs are contained in a variety of chemicals that can be found in household products and may have undesirable effects on health. Thereby, it is important to model blood-to-liver partition coefficients (log Pliver for VOCs in a fast and inexpensive way. In this paper, we present two new quantitative structure-property relationship (QSPR models for the prediction of log Pliver, where we also propose a hybrid approach for the selection of the descriptors. This hybrid methodology combines a machine learning method with a manual selection based on expert knowledge. This allows obtaining a set of descriptors that is interpretable in physicochemical terms. Our regression models were trained using decision trees and neural networks and validated using an external test set. Results show high prediction accuracy compared to previous log Pliver models, and the descriptor selection approach provides a means to get a small set of descriptors that is in agreement with theoretical understanding of the target property.

  12. 3D-QSPR Method of Computational Technique Applied on Red Reactive Dyes by Using CoMFA Strategy

    Directory of Open Access Journals (Sweden)

    Shahnaz Perveen

    2011-12-01

    Full Text Available Cellulose fiber is a tremendous natural resource that has broad application in various productions including the textile industry. The dyes, which are commonly used for cellulose printing, are “reactive dyes” because of their high wet fastness and brilliant colors. The interaction of various dyes with the cellulose fiber depends upon the physiochemical properties that are governed by specific features of the dye molecule. The binding pattern of the reactive dye with cellulose fiber is called the ligand-receptor concept. In the current study, the three dimensional quantitative structure property relationship (3D-QSPR technique was applied to understand the red reactive dyes interactions with the cellulose by the Comparative Molecular Field Analysis (CoMFA method. This method was successfully utilized to predict a reliable model. The predicted model gives satisfactory statistical results and in the light of these, it was further analyzed. Additionally, the graphical outcomes (contour maps help us to understand the modification pattern and to correlate the structural changes with respect to the absorptivity. Furthermore, the final selected model has potential to assist in understanding the charachteristics of the external test set. The study could be helpful to design new reactive dyes with better affinity and selectivity for the cellulose fiber.

  13. Experimental and QSPR Studies on n-Octanol/water Partition Coefficient(lgKow) of Substituted Aniline

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The n-octanol/water partition coefficients (lgKow) of 18 substituted anilines were determined at 25 ℃ by shake-flask method. The geometrical optimization of substituted anilines has been performed at B3LYP/6-311G** level with Gaussian98 program, and the molecular surface areas of substituted anilines were calculated using ChemOffice 2004 program. The calculated structural parameters of substituted anilines were used as theoretical descriptors and the two-parameter (molecular surface area (MA) and the energy of the highest occupied molecular orbital (EHOMO)) quantitative structure-property relationship (QSPR) model of lgKow for substituted aniline with molecular structural parameters was developed by multi-linear regression method. The regression coefficient square (r2) is 0.990 and the standard deviation SE 0.109. The model was validated by variance inflation factors (VIF) and t-test, and the results show that there exists small self-correlation between variables of the model with perfect stability. The model gives results in good qualitative agreement with experimental data. At last, the model was applied to predict lgKow values of five substituted anilines whose lgKow values have not been determined experimentally.

  14. QSPR models for predicting generator-column-derived octanol/water and octanol/air partition coefficients of polychlorinated biphenyls.

    Science.gov (United States)

    Yuan, Jintao; Yu, Shuling; Zhang, Ting; Yuan, Xuejie; Cao, Yunyuan; Yu, Xingchen; Yang, Xuan; Yao, Wu

    2016-06-01

    Octanol/water (KOW) and octanol/air (KOA) partition coefficients are two important physicochemical properties of organic substances. In current practice, KOW and KOA values of some polychlorinated biphenyls (PCBs) are measured using generator column method. Quantitative structure-property relationship (QSPR) models can serve as a valuable alternative method of replacing or reducing experimental steps in the determination of KOW and KOA. In this paper, two different methods, i.e., multiple linear regression based on dragon descriptors and hologram quantitative structure-activity relationship, were used to predict generator-column-derived log KOW and log KOA values of PCBs. The predictive ability of the developed models was validated using a test set, and the performances of all generated models were compared with those of three previously reported models. All results indicated that the proposed models were robust and satisfactory and can thus be used as alternative models for the rapid assessment of the KOW and KOA of PCBs. PMID:26943944

  15. Developing a support vector machine based QSPR model for prediction of half-life of some herbicides.

    Science.gov (United States)

    Samghani, Kobra; HosseinFatemi, Mohammad

    2016-07-01

    The half-life (t1/2) of 58 herbicides were modeled by quantitative structure-property relationship (QSPR) based molecular structure descriptors. After calculation and the screening of a large number of molecular descriptors, the most relevant those ones selected by stepwise multiple linear regression were used for developing linear and nonlinear models which developed by using multiple linear regression and support vector machine, respectively. Comparison between statistical parameters of linear and nonlinear models indicates the suitability of SVM over MLR model for predicting the half-life of herbicides. The statistical parameters of R(2) and standard error for training set of SVM model were; 0.96 and 0.087, respectively, and were 0.93 and 0.092 for the test set. The SVM model was evaluated by leave one out cross validation test, which its result indicates the robustness and predictability of the model. The established SVM model was used for predicting the half-life of other herbicides that are located in the applicability domain of model that were determined via leverage approach. The results of this study indicate that the relationship among selected molecular descriptors and herbicide's half-life is non-linear. These results emphases that the process of degradation of herbicides in the environment is very complex and can be affected by various environmental and structural features, therefore simple linear model cannot be able to successfully predict it. PMID:26970881

  16. A QSPR Study for the Prediction of the pKa of N-Base Ligands and Formation Constant Kc of Bis(2,2′-bipyridine)Platinum(II)-N-Base Adducts Using Quantum Mechanically Derived Descriptors

    OpenAIRE

    Selami Palaz; Baki Türkkan; Erol Eroğlu

    2012-01-01

    Quantitative structure-property relationship (QSPR) study on the acid dissociation constant, pKa of various 22 N-base ligands including pyridines, pyrimidines, purines, and quinolines has been carried out using Codessa Pro methodology and software. In addition, the formation constant, Kc of these ligands with Pt(II)(bpy)2 2+ (bpy = 2,2′-bipyridine) ion has also been modelled with the same methodology. Linear regression QSPR models of pKa and Kc were established with descriptors derived from A...

  17. A 2D-QSPR approach to predict blood-brain barrier penetration of drugs acting on the central nervous system

    Directory of Open Access Journals (Sweden)

    Matheus Malta de Sá

    2010-12-01

    Full Text Available Drugs acting on the central nervous system (CNS have to cross the blood-brain barrier (BBB in order to perform their pharmacological actions. Passive BBB diffusion can be partially expressed by the blood/brain partition coefficient (logBB. As the experimental evaluation of logBB is time and cost consuming, theoretical methods such as quantitative structure-property relationships (QSPR can be useful to predict logBB values. In this study, a 2D-QSPR approach was applied to a set of 28 drugs acting on the CNS, using the logBB property as biological data. The best QSPR model [n = 21, r = 0.94 (r² = 0.88, s = 0.28, and Q² = 0.82] presented three molecular descriptors: calculated n-octanol/water partition coefficient (ClogP, polar surface area (PSA, and polarizability (α. Six out of the seven compounds from the test set were well predicted, which corresponds to good external predictability (85.7%. These findings can be helpful to guide future approaches regarding those molecular descriptors which must be considered for estimating the logBB property, and also for predicting the BBB crossing ability for molecules structurally related to the investigated set.Fármacos que atuam no sistema nervoso central (SNC devem atravessar a barreira hematoencefálica (BHE para exercerem suas ações farmacológicas. A difusão passiva através da BHE pode ser parcialmente expressa pelo coeficiente de partição entre os compartimentos encefálico e sanguíneo (logBB, brain/blood partition coefficient. Considerando-se que a avaliação experimental de logBB é dispendiosa e demorada, métodos teóricos como estudos das relações entre estrutura química e propriedade (QSPR, Quantitative Structure-Property Relationships podem ser utilizados na previsão dos valores de logBB. Neste estudo, uma abordagem de QSPR-2D foi aplicada a um conjunto de 28 moléculas com ação central, usando logBB como propriedade biológica. O melhor modelo de QSPR [n = 21, r = 0,94 (r

  18. Eosinophil count - absolute

    Science.gov (United States)

    Eosinophils; Absolute eosinophil count ... the white blood cell count to give the absolute eosinophil count. ... than 500 cells per microliter (cells/mcL). Normal value ranges may vary slightly among different laboratories. Talk ...

  19. QSPR models based on molecular mechanics and quantum chemical calculations. 1. Construction of Boltzmann averaged descriptors for alkanes, alcohols, diols, ethers and cyclic compounds

    DEFF Research Database (Denmark)

    Dyekjær, Jane Dannow; Rasmussen, Kjeld; Jonsdottir, Svava Osk

    2002-01-01

    Values for nine descriptors for QSPR (quantitative structure-property relationships) modeling of physical properties of 96 alkanes, alcohols, ethers, diols, triols and cyclic alkanes and alcohols in conjunction with the program Codessa are presented. The descriptors are Boltzmann-averaged by...... selection of the most relevant conformers out of a set of possible molecular conformers generated by a systematic scheme presented in this paper. Six of these descriptors are calculated with molecular mechanics and three with quantum chemical methods. Especially interesting descriptors are the relative van...

  20. Improved QSPR Study of Diamagnetic Susceptibilities for Organic Compounds Using Two Novel Molecular Connectivity Indexes

    Institute of Scientific and Technical Information of China (English)

    MU Lailong; HE Hongmei; YANG Weihua

    2009-01-01

    For predicting the molar diamagnetic susceptibilities of organic compounds, a variable molecular connectivity index mχ' and its converse index mχ" based on adjacency matrix of molecular graphs and the variable atomic valence connectivity index δi' were proposed. The optimal values of parameters x, a, and y included in definition of δi', mχ' and mχ" can be found by an optimization method. When x=2.9, a= 1.10, and y=0.36, a good five-parameter model for the molar diamagnetic susceptibilities can be constructed from 0χ',1χ',2χ',1χ" and 2χ" by using the best subset re-gression analysis method. The correlation coefficient r, standard error s, and average absolute deviation of the mul-tilinear regression (MLR) model are 0.9930, 4.96 cgs, and 3.74 cgs, respectively, for the 721 organic compounds (training set). The cross-validation by using the leave-one-out method demonstrates that the MLR model is highly reliable from the point of view of statistics. The average absolute deviation of predicted values of the molar dia-magnetic susceptibility of another 360 organic compounds (test set) is 4.37 cgs for the MLR model. The results show that the current method is more effective than literature methods for estimating the molar diamagnetic suscep-tibility of an organic compound. The MLR method can provide an acceptable model for the prediction of the molar diamagnetic susceptibilities of organic compounds.

  1. The Big Pumpkin Count.

    Science.gov (United States)

    Coplestone-Loomis, Lenny

    1981-01-01

    Pumpkin seeds are counted after students convert pumpkins to jack-o-lanterns. Among the activities involved, pupils learn to count by 10s, make estimates, and to construct a visual representation of 1,000. (MP)

  2. White Blood Cell Count

    Science.gov (United States)

    ... and does not endorse non-AACC products and services. Advertising & Sponsorship: Policy | Opportunities PLEASE NOTE: Your web browser does not have JavaScript enabled. Unless you enable ... Share this page: Was this page helpful? Also known as: WBC Count; Leukocyte Count; White Count Formal name: White ...

  3. Molecular modelling studies on 2-amino 6-aryl-sulphonylbenzonitriles as non-nucleoside reverse transcriptase inhibitors of HIV-1: A QSPR approach

    Indian Academy of Sciences (India)

    Nitin S Sapre; Nilanjana Pancholi; Swagata Gupta; Arun Sikrwar; Neelima Sapre

    2007-11-01

    Lipophilicity or hydrophobicity is a crucial physico-chemical property of an oral drug compound. In the present study, we have analysed the structural parameters responsible for enhancing the lipophilicity expressed in terms of Octanol-Water partition coefficient, log , of 2-amino-6-arylsulfonylbenzonitrile (AASBN) derivatives used as NNRTIs in AIDS therapy. Connectivity based Randic () and Balaban () and atomistic Kier-Hall electrotopological state (-state) indices have been used to develop Quantitative Structure-Property Relationship (QSPR) and to predict the effect of substitution on the log . Model has been developed using multiple linear regression analysis (MLR) for the training set (67 compounds) and the model was tested on a test set (7 compounds). Significant results were obtained for the training set (2 = 0.948, $R^2_{\\text{adj}} = 0.939$, = 0.177, -ratio = 101.22). The results of the test set too implicated a good fit (2 = 0.941, $R^2_{\\text{adj}} = 0.929$, = 0.157, -ratio = 80.05). Among the two connectivity based topological indices; Randic () index showed better predictive ability than the Balaban () index. Kier-Hall -state indices indicated that among the functional groups, methyl, bromo, chloro groups on ring A, with their positive coefficients enhanced the lipophilicity. Amino, cyano group on ring B and the bridging S, SO, SO2 with their negative coefficients showed an adverse effect on the lipophilicity parameter. Thus, Kier-Hall -state indices along with topological indices could be well applied for deriving QSPR models and analysing substitution effects of various functional groups. The training set, correlation matrix and observed and experimental log values are available as supplementary material for this article.

  4. Counting techniques-statistics

    International Nuclear Information System (INIS)

    Referring to the determination of the activity of a given sample, the distribution of the counting results is analysed. The relation between the standard deviation and normal Gauss curve is studied. Student's -t-and X2 tests are presented in the systematic errors determination. Problems are discussed, such as: elimination of background radiation counting, optimum distribution of counting times, criterion of choice and adjustment of the equipment, as well as the elimination of doubtful results

  5. Health Physics counting room

    CERN Multimedia

    1970-01-01

    The Health Physics counting room, where the quantity of induced radioactivity in materials is determined. This information is used to evaluate possible radiation hazards from the material investigated.

  6. Atom trap trace analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Z.-T.; Bailey, K.; Chen, C.-Y.; Du, X.; Li, Y.-M.; O' Connor, T. P.; Young, L.

    2000-05-25

    A new method of ultrasensitive trace-isotope analysis has been developed based upon the technique of laser manipulation of neutral atoms. It has been used to count individual {sup 85}Kr and {sup 81}Kr atoms present in a natural krypton sample with isotopic abundances in the range of 10{sup {minus}11} and 10{sup {minus}13}, respectively. The atom counts are free of contamination from other isotopes, elements,or molecules. The method is applicable to other trace-isotopes that can be efficiently captured with a magneto-optical trap, and has a broad range of potential applications.

  7. Counting trees using symmetries

    CERN Document Server

    Bernardi, Olivier

    2012-01-01

    We present a new approach for counting trees, and we apply it to count multitype Cayley trees and to prove the multivariate Lagrange inversion formula. The gist of our approach is to exploit the symmetries of refined enumerative formulas: proving these symmetries is easy, and once the symmetries are proved the formulas follow effortlessly. Somewhat surprisingly, our formula for the generating function of multitype Cayley trees appears to be new, and implies certain recent results by Bousquet-M\\'elou and Chapuy. We also adapt our approach to recover known enumerative formulas for cacti counted according to their degree distribution.

  8. Sublattice Counting and Orbifolds

    CERN Document Server

    Hanany, Amihay; Reffert, Susanne

    2010-01-01

    Abelian orbifolds of C^3 are known to be encoded by hexagonal brane tilings. To date it is not known how to count all such orbifolds. We fill this gap by employing number theoretic techniques from crystallography, and by making use of Polya's Enumeration Theorem. The results turn out to be beautifully encoded in terms of partition functions and Dirichlet Series. The same methods apply to counting orbifolds of any toric non-compact Calabi-Yau singularity. As additional examples, we count the orbifolds of the conifold, of the L^{aba} theories, and of C^4.

  9. Sublattice counting and orbifolds

    Science.gov (United States)

    Hanany, Amihay; Orlando, Domenico; Reffert, Susanne

    2010-06-01

    Abelian orbifolds of mathbb{C}3 are known to be encoded by hexagonal brane tilings. To date it is not known how to count all such orbifolds. We fill this gap by employing number theoretic techniques from crystallography, and by making use of Polya's Enumeration Theorem. The results turn out to be beautifully encoded in terms of partition functions and Dirichlet series. The same methods apply to counting orbifolds of any toric non-compact Calabi-Yau singularity. As additional examples, we count the orbifolds of the conifold, of the L aba theories, and of mathbb{C}4.

  10. Calorie count - Alcoholic beverages

    Science.gov (United States)

    ... you drink. Cocktails mixed with soda, cream, or ice cream can have especially high calorie counts. If you ... A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among ...

  11. 1996 : Track Count Protocol

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The goal of St. Vincent National Wildlife Refuge's Track Count Protocol is to provide an index to the population size of game animals inhabiting St. Vincent Island.

  12. Blood Count Tests

    Science.gov (United States)

    Your blood contains red blood cells (RBC), white blood cells (WBC), and platelets. Blood count tests measure the number and types of cells in your blood. This helps doctors check on your overall health. ...

  13. Counting Knights and Knaves

    Science.gov (United States)

    Levin,Oscar; Roberts, Gerri M.

    2013-01-01

    To understand better some of the classic knights and knaves puzzles, we count them. Doing so reveals a surprising connection between puzzles and solutions, and highlights some beautiful combinatorial identities.

  14. Housing Inventory Count

    Data.gov (United States)

    Department of Housing and Urban Development — This report displays the data communities reported to HUD about the nature of their dedicated homeless inventory, referred to as their Housing Inventory Count...

  15. Influence of atomic and nuclear constants on the counting efficiency for 55{sup F}e in liquid scintillators; Influencia de los parametros atomicos y nucleares en la calibracion de 55{sup F}e mediante centelleo liquido

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, A.; Grau, A.; Arcos, J. M. los

    1985-07-01

    In this paper one considers the influence of the different parameters on the determination of the uncertainty of the detection efficiency for 55{sup F}e when the counting technique of liquid scintillation is applied. The following parameters are considered: the relative probabilities of X and Auger emission so as their corresponding energies, the fluorescence yields W{sup K} and W{sup L}, and the non-interaction probabilities of the emitted X photons. (Author) 11 refs.

  16. Design of an alpha-particle counting system at a defined solid angle at Turkish atomic energy authority-Sarayköy nuclear research and training center (TAEK-SANAEM)

    Science.gov (United States)

    Seferinoğlu, Meryem; Yeltepe, Emin

    2015-12-01

    The design details of an alpha-particle counting set-up at a defined solid angle (ACS-DSA) constructed in Radionuclide Metrology Department at TAEK-SANAEM for use in the primary standardization of radioactive solutions and determination of nuclear decay data of alpha-particle emitters is presented. The counting system is designed such that the solid angle is very well-defined and directly traceable to the national standards. The design involves mechanical construction of different parts like the source chamber, various coaxial flanges, and circular diaphragms in front of the passivated implanted planar silicon (PIPS®) detector, distance tubes, a digital caliper and a sliding piston to allow for different measurement configurations. All geometric configurations are easily changeable and characterisable with high accuracy which facilitates the solid angle calculation. A mixed alpha source was counted to check performance of assembled ACS-DSA system and good energy resolution and low peak tailing in the alpha energy spectrum was observed for small diaphragm apertures and far source-to-detector geometries.

  17. PREDICTING THE BOILING POINT OF PCDD/Fs BY THE QSPR METHOD BASED ON THE MOLECULAR DISTANCE-EDGE VECTOR INDEX

    Directory of Open Access Journals (Sweden)

    Long Jiao

    2015-05-01

    Full Text Available The quantitative structure property relationship (QSPR for the boiling point (Tb of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs was investigated. The molecular distance-edge vector (MDEV index was used as the structural descriptor. The quantitative relationship between the MDEV index and Tb was modeled by using multivariate linear regression (MLR and artificial neural network (ANN, respectively. Leave-one-out cross validation and external validation were carried out to assess the prediction performance of the models developed. For the MLR method, the prediction root mean square relative error (RMSRE of leave-one-out cross validation and external validation was 1.77 and 1.23, respectively. For the ANN method, the prediction RMSRE of leave-one-out cross validation and external validation was 1.65 and 1.16, respectively. A quantitative relationship between the MDEV index and Tb of PCDD/Fs was demonstrated. Both MLR and ANN are practicable for modeling this relationship. The MLR model and ANN model developed can be used to predict the Tb of PCDD/Fs. Thus, the Tb of each PCDD/F was predicted by the developed models.

  18. Ant Colony Optimization as a Powerful Tool for Descriptor Selection in QSPR Study of Infinite Dilution Activity Coefficients of Halogenated Hydrocarbons in Water

    Institute of Scientific and Technical Information of China (English)

    Morteza Atabati

    2012-01-01

    A quantitative structure-property relationship (QSPR) study was suggested for the prediction of infinite dilution activity coefficients of halogenated hydrocarbons, γ∞ , in water at 298.15 K. After optimization of 3D geometry of the halogenated hydrocarbons with semi-empirical quantum chemical calculations at the AM1 level, different descriptors (1514 descriptors) were calculated by the HyperChem and Dragon softwares. A major problem of QSPR is the high dimensionality of the descriptor space; therefore, descriptor selection is the most important step. In this paper, an ant colony optimization (ACO) algorithm was proposed to select the best descriptors. Then the selected descriptors were applied for model development using multiple linear regression. The average absolute relative deviation and correlation coefficient for the training set were obtained as 4.36% and 0.951, respectively, while the corresponding values for the test set were 5.96% and 0.929, respectively. The results showed that the applied procedure is suitable for the prediction of γ∞ of halogenated hydrocarbons in water.

  19. Alpha scintillation radon counting

    International Nuclear Information System (INIS)

    Radon counting chambers which utilize the alpha-scintillation properties of silver activated zinc sulfide are simple to construct, have a high efficiency, and, with proper design, may be relatively insensitive to variations in the pressure or purity of the counter filling. Chambers which were constructed from glass, metal, or plastic in a wide variety of shapes and sizes were evaluated for the accuracy and the precision of the radon counting. The principles affecting the alpha-scintillation radon counting chamber design and an analytic system suitable for a large scale study of the 222Rn and 226Ra content of either air or other environmental samples are described. Particular note is taken of those factors which affect the accuracy and the precision of the method for monitoring radioactivity around uranium mines

  20. Photon counting digital holography

    Science.gov (United States)

    Demoli, Nazif; Skenderović, Hrvoje; Stipčević, Mario; Pavičić, Mladen

    2016-05-01

    Digital holography uses electronic sensors for hologram recording and numerical method for hologram reconstruction enabling thus the development of advanced holography applications. However, in some cases, the useful information is concealed in a very wide dynamic range of illumination intensities and successful recording requires an appropriate dynamic range of the sensor. An effective solution to this problem is the use of a photon-counting detector. Such detectors possess counting rates of the order of tens to hundreds of millions counts per second, but conditions of recording holograms have to be investigated in greater detail. Here, we summarize our main findings on this problem. First, conditions for optimum recording of digital holograms for detecting a signal significantly below detector's noise are analyzed in terms of the most important holographic measures. Second, for time-averaged digital holograms, optimum recordings were investigated for exposures shorter than the vibration cycle. In both cases, these conditions are studied by simulations and experiments.

  1. Rainflow counting revisited

    Energy Technology Data Exchange (ETDEWEB)

    Soeker, H. [Deutsches Windenergie-Institut (Germany)

    1996-09-01

    As state of the art method the rainflow counting technique is presently applied everywhere in fatigue analysis. However, the author feels that the potential of the technique is not fully recognized in wind energy industries as it is used, most of the times, as a mere data reduction technique disregarding some of the inherent information of the rainflow counting results. The ideas described in the following aim at exploitation of this information and making it available for use in the design and verification process. (au)

  2. Computerized radioautographic grain counting

    International Nuclear Information System (INIS)

    In recent years, radiolabeling techniques have become fundamental assays in physiology and biochemistry experiments. They also have assumed increasingly important roles in morphologic studies. Characteristically, radioautographic analysis of structure has been qualitative rather than quantitative, however, microcomputers have opened the door to several methods for quantifying grain counts and density. The overall goal of this chapter is to describe grain counting using the Bioquant, an image analysis package based originally on the Apple II+, and now available for several popular microcomputers. The authors discuss their image analysis procedures by applying them to a study of development in the central nervous system

  3. Counting rate logarithmic circuits

    International Nuclear Information System (INIS)

    This paper describes the basic circuit and the design method for a multidecade logarithmic counting ratemeter. The method is based on the charging and discharging of several RC time constants. An F.E.T. switch is used and the drain current is converted into a proportional voltage by a current to voltage converter. The logarithmic linearity was estimated for 4 decades starting from 50 cps. This circuit can be used in several nuclear instruments like survey meters and counting systems. This circuits has been developed as part of campbell channel instrumentation. (author)

  4. What Counts as Evidence?

    Science.gov (United States)

    Dougherty Stahl, Katherine A.

    2014-01-01

    Each disciplinary community has its own criteria for determining what counts as evidence of knowledge in their academic field. The criteria influence the ways that a community's knowledge is created, communicated, and evaluated. Situating reading, writing, and language instruction within the content areas enables teachers to explicitly…

  5. Counting Hexagonal Lattice Animals

    OpenAIRE

    Mohammed, Mohamud

    2002-01-01

    We describe Maple packages for the automatic generation of generating functions(and series expansions) for counting lattice animals(fixed polyominoes), in the two-dimensional hexagonal lattice, of bounded but arbitrary width. Our Maple packages(complete with source code) are easy-to-use and available from my website.

  6. Counting on rectangular areas

    OpenAIRE

    Janjic, Milan

    2007-01-01

    In the first section of this paper we prove a theorem for the number of columns of a rectangular area that are identical to the given one. In the next section we apply this theorem to derive several combinatorial identities by counting specified subsets of a finite set.

  7. QSPR study of standard absolute entropies for gaseous organic compounds using novel molecular connectivity indexes and Ring parameter

    International Nuclear Information System (INIS)

    Highlights: ► Variable atomic valence connectivity index δ′i, Ring parameter H, and variable molecular connectivity index mχ′k were proposed. ► A good four-parameter model can be constructed from H and mχ′k by using the best subsets regression analysis method. ► The MLR method can provide an accurate model for the prediction of the standard absolute entropies of gaseous organic compounds. - Abstract: For predicting the standard absolute entropies of gaseous organic compounds, variable molecular connectivity index mχ′k and Ring parameter H, based on adjacency matrix of molecular graphs, variable atomic valence connectivity index δ′i, and the numbers of chains (cycles) atomic of molecule niR, were proposed. The optimal values of parameters c, a, mi, and y included in the definition of δ′i, and mχ′k can be found by optimization method. When c = 0.91, a = 1.3, and y = 0.22, a good four-parameter model can be constructed from H and mχ′k by using the best subsets regression analysis method for the standard absolute entropies of gaseous organic compounds. The results show that the MLR method can provide an accurate model for the prediction of the standard absolute entropies of gaseous organic compounds.

  8. The Syntax and Semantics of Purepecha Noun Phrases and the Mass/Count Distinction

    Science.gov (United States)

    Vazquez Rojas Maldonado, Violeta

    2012-01-01

    Purepecha (isolate, central Western Mexico) nouns can be assigned to one of three classes depending on their inherent number characteristics: count nouns denote atomic units, mass nouns denote plural entities and count-mass nouns (Doetjes 1997) denote sets that contain pluralities and atomic units as well. This tri-partite distinction guides the…

  9. Fragments of approximate counting

    Czech Academy of Sciences Publication Activity Database

    Buss, S.R.; Kolodziejczyk, L.. A.; Thapen, Neil

    2014-01-01

    Roč. 79, č. 2 (2014), s. 496-525. ISSN 0022-4812 R&D Projects: GA AV ČR IAA100190902 Institutional support: RVO:67985840 Keywords : approximate counting * bounded arithmetic * ordering principle Subject RIV: BA - General Mathematics Impact factor: 0.541, year: 2014 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9287274&fileId=S0022481213000376

  10. The right to count does not always count

    DEFF Research Database (Denmark)

    Sodemann, Morten

    2013-01-01

    The best prescription against illness is learning to read and to count. People who are unable to count have a harder time learning to read. People who have difficulty counting make poorer decisions, are less able to combine information and are less likely to have a strategy for life...

  11. CalCOFI Egg Counts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish egg counts and standardized counts for eggs captured in CalCOFI icthyoplankton nets (primarily vertical [Calvet or Pairovet], oblique [bongo or ring nets], and...

  12. A QSPR study on the solvent-induced frequency shifts of acetone and dimethyl sulfoxide in organic solvents.

    Science.gov (United States)

    Ou, Yu Heng; Chang, Chia Ming; Chen, Ying Shao

    2016-06-01

    In this study, solvent-induced frequency shifts (SIFS) in the infrared spectrum of acetone and dimethyl sulfoxide in organic solvents were investigated by using four types of quantum-chemical reactivity descriptors. The results showed that the SIFS of acetone is mainly affected by the electron-acceptance chemical potential and the maximum nucleophilic condensed local softness of organic solvents, which represent the electron flow and the polarization between acetone and solvent molecules. On the other hand, the SIFS of dimethyl sulfoxide changes with the maximum positive charge of hydrogen atom and the inverse of apolar surface area of solvent molecules, showing that the electrostatic and hydrophilic interactions are main mechanisms between dimethyl sulfoxide and solvent molecules. The introduction of the four-element theory model-based quantitative structure-property relationship approach improved the assessing quality and provided a basis for interpreting the solute-solvent interactions. PMID:26994584

  13. Counting RG flows

    Science.gov (United States)

    Gukov, Sergei

    2016-01-01

    Interpreting renormalization group flows as solitons interpolating between different fixed points, we ask various questions that are normally asked in soliton physics but not in renormalization theory. Can one count RG flows? Are there different "topological sectors" for RG flows? What is the moduli space of an RG flow, and how does it compare to familiar moduli spaces of (supersymmetric) dowain walls? Analyzing these questions in a wide variety of contexts — from counting RG walls to AdS/CFT correspondence — will not only provide favorable answers, but will also lead us to a unified general framework that is powerful enough to account for peculiar RG flows and predict new physical phenomena. Namely, using Bott's version of Morse theory we relate the topology of conformal manifolds to certain properties of RG flows that can be used as precise diagnostics and "topological obstructions" for the strong form of the C-theorem in any dimension. Moreover, this framework suggests a precise mechanism for how the violation of the strong C-theorem happens and predicts "phase transitions" along the RG flow when the topological obstruction is non-trivial. Along the way, we also find new conformal manifolds in well-known 4d CFT's and point out connections with the superconformal index and classifying spaces of global symmetry groups.

  14. Photon counting systems

    International Nuclear Information System (INIS)

    This paper is a review of the various photon counting systems, used in astronomy, at optical wavelengths. Technological differences between available devices are introduced according to the processes applied to these photoelectrons (multiplication and/or acceleration), and their impact targets (phosphors, photodetectors, resistive or conductive anodes...). Two detection processes are involved: threshold discrimination above noise for most types of devices, and analog measurement for systems using resistive and wedge-and-strip anodes. Devices currently used for astronomical observations are presented, and their performance characteristics. These devices are: photomultipliers, which are monopixel detectors, using multiplication with dynodes; images intensifiers cameras, most frequently read with CCDs; analog devices with resistive or wedge-and-strip anodes, behind microchannel plates (MCP); Digicons, using direct electronic bombardment; the MAMA detector, with coincidence anodes behind MCP; and then the PAPA detector using masks encoding readout. Dead time effects, which define the dynamic range are presented with some details. Finally, because of the improvement of low level readout noise devices (CCDs), the field of application of the photon counting techniques confines to the blue and the UV part of the spectrum, at low signal to noise ratios

  15. Combining radial basis function neural network with genetic algorithm to QSPR modeling of adsorption on multi-walled carbon nanotubes surface

    Science.gov (United States)

    Hassanzadeh, Zeinabe; Kompany-Zareh, Mohsen; Ghavami, Raouf; Gholami, Somayeh; Malek-Khatabi, Atefe

    2015-10-01

    The configuring of a radial basis function neural network (RBFN) consists of optimizing the architecture and the network parameters (centers, widths, and weights). Methods such as genetic algorithm (GA), K-means and cluster analysis (CA) are among center selection methods. In the most of reports on RBFN modeling optimum centers are selected among rows of descriptors matrix. A combination of RBFN and GA is introduced for better description of quantitative structure-property relationships (QSPR) models. In this method, centers are not exactly rows of the independent matrix and can be located in any point of the samples space. In the proposed approach, initial centers are randomly selected from the calibration set. Then GA changes the locations of the initially selected centers to find the optimum positions of centers from the whole space of scores matrix, in order to obtain highest prediction ability. This approach is called whole space GA-RBFN (wsGA-RBFN) and applied to predict the adsorption coefficients (logk), of 40 small molecules on the surface of multi-walled carbon nanotubes (MWCNTs). The data consists of five solute descriptors [R, π, α, β, V] of the molecules and known as data set1. Prediction ability of wsGA-RBFN is compared to GA-RBFN and MLR models. The obtained Q2 values for wsGA-RBFN, GA-RBFN and MLR are 0.95, 0.85, and 0.78, respectively, which shows the merit of wsGA-RBFN. The method is also applied on the logarithm of surface area normalized adsorption coefficients (logKSA), of organic compounds (OCs) on MWCNTs surface. The data set2 includes 69 aromatic molecules with 13 physicochemical properties of the OCs. Thirty-nine of these molecules were similar to those of data set1 and the others were aromatic compounds included of small and big molecules. Prediction ability of wsGA-RBFN for second data set was compared to GA-RBF. The Q2 values for wsGA-RBFN and GA-RBF are obtained as 0.89 and 0.80, respectively.

  16. LAWRENCE RADIATION LABORATORY COUNTING HANDBOOK

    Energy Technology Data Exchange (ETDEWEB)

    Group, Nuclear Instrumentation

    1966-10-01

    The Counting Handbook is a compilation of operational techniques and performance specifications on counting equipment in use at the Lawrence Radiation Laboratory, Berkeley. Counting notes have been written from the viewpoint of the user rather than that of the designer or maintenance man. The only maintenance instructions that have been included are those that can easily be performed by the experimenter to assure that the equipment is operating properly.

  17. SUMS Counts-Related Projects

    Data.gov (United States)

    Social Security Administration — Staging Instance for all SUMs Counts related projects including: Redeterminations/Limited Issue, Continuing Disability Resolution, CDR Performance Measures, Initial...

  18. Compton suppression gamma-counting: The effect of count rate

    Science.gov (United States)

    Millard, H.T., Jr.

    1984-01-01

    Past research has shown that anti-coincidence shielded Ge(Li) spectrometers enhanced the signal-to-background ratios for gamma-photopeaks, which are situated on high Compton backgrounds. Ordinarily, an anti- or non-coincidence spectrum (A) and a coincidence spectrum (C) are collected simultaneously with these systems. To be useful in neutron activation analysis (NAA), the fractions of the photopeak counts routed to the two spectra must be constant from sample to sample to variations must be corrected quantitatively. Most Compton suppression counting has been done at low count rate, but in NAA applications, count rates may be much higher. To operate over the wider dynamic range, the effect of count rate on the ratio of the photopeak counts in the two spectra (A/C) was studied. It was found that as the count rate increases, A/C decreases for gammas not coincident with other gammas from the same decay. For gammas coincident with other gammas, A/C increases to a maximum and then decreases. These results suggest that calibration curves are required to correct photopeak areas so quantitative data can be obtained at higher count rates. ?? 1984.

  19. Negative Binomial Process Count and Mixture Modeling.

    Science.gov (United States)

    Zhou, Mingyuan; Carin, Lawrence

    2015-02-01

    The seemingly disjoint problems of count and mixture modeling are united under the negative binomial (NB) process. A gamma process is employed to model the rate measure of a Poisson process, whose normalization provides a random probability measure for mixture modeling and whose marginalization leads to an NB process for count modeling. A draw from the NB process consists of a Poisson distributed finite number of distinct atoms, each of which is associated with a logarithmic distributed number of data samples. We reveal relationships between various count- and mixture-modeling distributions and construct a Poisson-logarithmic bivariate distribution that connects the NB and Chinese restaurant table distributions. Fundamental properties of the models are developed, and we derive efficient Bayesian inference. It is shown that with augmentation and normalization, the NB process and gamma-NB process can be reduced to the Dirichlet process and hierarchical Dirichlet process, respectively. These relationships highlight theoretical, structural, and computational advantages of the NB process. A variety of NB processes, including the beta-geometric, beta-NB, marked-beta-NB, marked-gamma-NB and zero-inflated-NB processes, with distinct sharing mechanisms, are also constructed. These models are applied to topic modeling, with connections made to existing algorithms under Poisson factor analysis. Example results show the importance of inferring both the NB dispersion and probability parameters. PMID:26353243

  20. 烃类及其衍生物闪点、沸点的定量构效关系%QSPR study for predicting flash points and boiling points of hydrocarbon and their derivatives

    Institute of Scientific and Technical Information of China (English)

    杨惠; 陈利平; 谢传欣; 石宁; 陈网桦

    2011-01-01

    The quantitative relationships existed between flash points, boiling points and molecular structures of hydrocarbon and their derivatives were investigated based on the quantitative structure-property relationship ( QSPR) study. 384 molecular descriptors of hydrocarbon and their derivatives were calculated by CODESSA, and these descriptors were pre-selected by best multilinear regression method. Then QSPR models about flash points and boiling points were built. As a result, the five-descriptor linear models were developed to describe the relationship between the molecular structures and the flash points or the boiling points. The non-linear regression models were built based on support vector machine using the five descriptors selected by best multilinear regression method. The compounds were divided into a training set and a test set. The squared correlation coefficient, cross-validation coefficient and mean squared error of each model were calculated. The test set was used to validate the prediction performance of the resulting models. The predicted results indicated that, the prediction results were in good agreement with the experimental values. The models of flash points had robustness, strong generative ability and small prediction error. The predicted results were satisfactory. But the predicted results of boiling points remained to be improved. Compared to the models of hydrocarbons, the performance of the models which added derivatives was decreased. It can be very helpful to expand the applied scope of QSPR study.%基于定量结构-性质相关性( QSPR)原理,研究了烃类及其衍生物闪点、沸点与其分子结构间的内在定量关系.应用CODESSA软件计算384种烃类及其衍生物的分子结构描述符,建立了闪点和沸点的QSPR模型.用最佳多元线性回归(B-MLR)方法筛选得到的分子描述符建立了线性回归模型.用B-MLR方法所选择的5个描述符作为支持向量机(SVM)的输入建立了非线性模型.

  1. Integrated counting system - user guide

    International Nuclear Information System (INIS)

    The facilities of a nucleonic counting system in one module in the standard 6000 series and its use in applications is described. Details are given of ways of employing the module for the rapid and low cost development of computer-based systems in nucleonic counting applications. (author)

  2. Hanford whole body counting manual

    International Nuclear Information System (INIS)

    This document, a reprint of the Whole Body Counting Manual, was compiled to train personnel, document operation procedures, and outline quality assurance procedures. The current manual contains information on: the location, availability, and scope of services of Hanford's whole body counting facilities; the administrative aspect of the whole body counting operation; Hanford's whole body counting facilities; the step-by-step procedure involved in the different types of in vivo measurements; the detectors, preamplifiers and amplifiers, and spectroscopy equipment; the quality assurance aspect of equipment calibration and recordkeeping; data processing, record storage, results verification, report preparation, count summaries, and unit cost accounting; and the topics of minimum detectable amount and measurement accuracy and precision. 12 refs., 13 tabs

  3. Hanford whole body counting manual

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, H.E.; Brim, C.P.; Rieksts, G.A.; Rhoads, M.C.

    1987-05-01

    This document, a reprint of the Whole Body Counting Manual, was compiled to train personnel, document operation procedures, and outline quality assurance procedures. The current manual contains information on: the location, availability, and scope of services of Hanford's whole body counting facilities; the administrative aspect of the whole body counting operation; Hanford's whole body counting facilities; the step-by-step procedure involved in the different types of in vivo measurements; the detectors, preamplifiers and amplifiers, and spectroscopy equipment; the quality assurance aspect of equipment calibration and recordkeeping; data processing, record storage, results verification, report preparation, count summaries, and unit cost accounting; and the topics of minimum detectable amount and measurement accuracy and precision. 12 refs., 13 tabs.

  4. sup 4 sup 4 Ti atom counting for nuclear astrophysics

    CERN Document Server

    Hui, S K; Berkovits, D; Boaretto, E; Ghelberg, S; Hass, M; Hershkowitz, A; Navon, E

    2000-01-01

    The nuclide sup 4 sup 4 Ti (T sub 1 sub / sub 2 =59.2 yr) has recently become an important asset to nuclear astrophysics through the measurement of its cosmic radioactivity, yielding significant information on fresh sup 4 sup 4 Ti nucleosynthesis in supernovae. We propose to use AMS to determine the production rate of sup 4 sup 4 Ti by the main channel believed to be responsible for sup 4 sup 4 Ti astrophysical production, namely sup 4 sup 0 Ca(alpha,gamma). A preliminary experiment conducted at the Koffler 14UD Pelletron accelerator demonstrates a sensitivity of 1x10 sup - sup 1 sup 4 for the sup 4 sup 4 Ti/Ti ratio. The AMS detection was performed using sup 4 sup 4 Ti sup - ions sputtered from a TiO sub 2 sample, reducing considerably the sup 4 sup 4 Ca isobaric interference. The present limit corresponds effectively to sup 4 sup 4 Ti production with resonance strength in the range 10-100 meV for a one-day sup 4 sup 0 Ca(alpha,gamma) activation. Several such resonances are known to be responsible for sup 4 ...

  5. High Count Rate Single Photon Counting Detector Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An optical communications receiver requires efficient and high-rate photon-counting capability so that the information from every photon, received at the aperture,...

  6. Fundamental uncertainties in lung counting.

    Science.gov (United States)

    Kramer, Gary H; Hauck, Barry M

    2007-10-01

    The HML has investigated the effect the uncertainty introduced into an activity estimate from a lung count due to 1) replicate counts and 2) lung set variability. Replicate counts in the HML seem to only be affected by random statistics as the uncertainty can be predicted by Monte Carlo simulations. These findings from the lung set variability experiments suggest that a lung set has an unquantified uncertainty on its activity that adds a component to the uncertainty on the counting efficiency, and ultimately the activity estimate, as they can differ by as much as 30% at 17.5 keV or about 13% at 185.7 keV, when one is expecting only a 3% difference. PMID:17846529

  7. Counting Word Frequencies with Python

    OpenAIRE

    William J. Turkel; Adam Crymble

    2012-01-01

    Your list is now clean enough that you can begin analyzing its contents in meaningful ways. Counting the frequency of specific words in the list can provide illustrative data. Python has an easy way to count frequencies, but it requires the use of a new type of variable: the dictionary. Before you begin working with a dictionary, consider the processes used to calculate frequencies in a list.

  8. Counting Word Frequencies with Python

    Directory of Open Access Journals (Sweden)

    William J. Turkel

    2012-07-01

    Full Text Available Your list is now clean enough that you can begin analyzing its contents in meaningful ways. Counting the frequency of specific words in the list can provide illustrative data. Python has an easy way to count frequencies, but it requires the use of a new type of variable: the dictionary. Before you begin working with a dictionary, consider the processes used to calculate frequencies in a list.

  9. Particle Counting Statistics of Time and Space Dependent Fields

    CERN Document Server

    Braungardt, Sibylle; Glauber, Roy J; Lewenstein, Maciej

    2011-01-01

    The counting statistics give insight into the properties of quantum states of light and other quantum states of matter such as ultracold atoms or electrons. The theoretical description of photon counting was derived in the 1960s and was extended to massive particles more recently. Typically, the interaction between each particle and the detector is assumed to be limited to short time intervals, and the probability of counting particles in one interval is independent of the measurements in previous intervals. There has been some effort to describe particle counting as a continuous measurement, where the detector and the field to be counted interact continuously. However, no general formula applicable to any time and space dependent field has been derived so far. In our work, we derive a fully time and space dependent description of the counting process for linear quantum many-body systems, taking into account the back-action of the detector on the field. We apply our formalism to an expanding Bose-Einstein con...

  10. Standardization of 241Am by digital coincidence counting, liquid scintillation counting and defined solid angle counting

    CERN Document Server

    Balpardo, C; Rodrigues, D; Arenillas, P

    2010-01-01

    The nuclide 241Am decays by alpha emission to 237Np. Most of the decays (84.6 %) populate the excited level of 237Np with energy of 59.54 keV. Digital Coincidence Counting was applied to standardize a solution of 241Am by alpha-gamma coincidence counting with efficiency extrapolation. Electronic discrimination was implemented with a pressurized proportional counter and the results were compared with two other independent techniques: Liquid Scintillation Counting using the logical sum of double coincidences in a TDCR array and Defined Solid Angle Counting taking into account activity inhomogeneity in the active deposit. The results show consistency between the three methods within a limit of a 0.3%. An ampoule of this solution will be sent to the International Reference System (SIR) during 2009. Uncertainties were analysed and compared in detail for the three applied methods.

  11. Cerenkov counting as a complement to liquid scintillation counting

    International Nuclear Information System (INIS)

    A commercially available spectrometer was calibrated for liquid scintillation (LS) and Cerenkov counting efficiency (CCE) using National Institute of Standards and Technology traceable solutions. The CCE increased linearly over a 3 order of magnitude range in 40K β activity, and by 42% per MeV as β-energies increased from 0.300 to 3.54 MeV, achieving a maximum value of 80% for 106Ru/106Rh The CCE can be enhanced by 10-15% when a wavelength shifter is used. A comparison of the data showed that the CCE was typically 20-50% less than the LS counting efficiency for β-particles with maximum energies >1 MeV. Applications that utilize sequential CCE and LS counting to quantitate activity concentrations are discussed for samples containing two β-emitting nuclides of differing energies. (Author)

  12. Hanford whole body counting manual

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, H.E.; Rieksts, G.A.; Lynch, T.P.

    1990-06-01

    This document describes the Hanford Whole Body Counting Program as it is administered by Pacific Northwest Laboratory (PNL) in support of the US Department of Energy--Richland Operations Office (DOE-RL) and its Hanford contractors. Program services include providing in vivo measurements of internally deposited radioactivity in Hanford employees (or visitors). Specific chapters of this manual deal with the following subjects: program operational charter, authority, administration, and practices, including interpreting applicable DOE Orders, regulations, and guidance into criteria for in vivo measurement frequency, etc., for the plant-wide whole body counting services; state-of-the-art facilities and equipment used to provide the best in vivo measurement results possible for the approximately 11,000 measurements made annually; procedures for performing the various in vivo measurements at the Whole Body Counter (WBC) and related facilities including whole body counts; operation and maintenance of counting equipment, quality assurance provisions of the program, WBC data processing functions, statistical aspects of in vivo measurements, and whole body counting records and associated guidance documents. 16 refs., 48 figs., 22 tabs.

  13. Hanford whole body counting manual

    International Nuclear Information System (INIS)

    This document describes the Hanford Whole Body Counting Program as it is administered by Pacific Northwest Laboratory (PNL) in support of the US Department of Energy--Richland Operations Office (DOE-RL) and its Hanford contractors. Program services include providing in vivo measurements of internally deposited radioactivity in Hanford employees (or visitors). Specific chapters of this manual deal with the following subjects: program operational charter, authority, administration, and practices, including interpreting applicable DOE Orders, regulations, and guidance into criteria for in vivo measurement frequency, etc., for the plant-wide whole body counting services; state-of-the-art facilities and equipment used to provide the best in vivo measurement results possible for the approximately 11,000 measurements made annually; procedures for performing the various in vivo measurements at the Whole Body Counter (WBC) and related facilities including whole body counts; operation and maintenance of counting equipment, quality assurance provisions of the program, WBC data processing functions, statistical aspects of in vivo measurements, and whole body counting records and associated guidance documents. 16 refs., 48 figs., 22 tabs

  14. Atom Chips

    CERN Document Server

    Folman, R; Cassettari, D; Hessmo, B; Maier, T; Schmiedmayer, J; Folman, Ron; Krüger, Peter; Cassettari, Donatella; Hessmo, Björn; Maier, Thomas

    1999-01-01

    Atoms can be trapped and guided using nano-fabricated wires on surfaces, achieving the scales required by quantum information proposals. These Atom Chips form the basis for robust and widespread applications of cold atoms ranging from atom optics to fundamental questions in mesoscopic physics, and possibly quantum information systems.

  15. On the Count of Trees

    CERN Document Server

    Barcenas, Everardo; Layaida, Nabil; Schmitt, Alan

    2010-01-01

    Regular tree grammars and regular path expressions constitute core constructs widely used in programming languages and type systems. Nevertheless, there has been little research so far on frameworks for reasoning about path expressions where node cardinality constraints occur along a path in a tree. We present a logic capable of expressing deep counting along paths which may include arbitrary recursive forward and backward navigation. The counting extensions can be seen as a generalization of graded modalities that count immediate successor nodes. While the combination of graded modalities, nominals, and inverse modalities yields undecidable logics over graphs, we show that these features can be combined in a decidable tree logic whose main features can be decided in exponential time. Our logic being closed under negation, it may be used to decide typical problems on XPath queries such as satisfiability, type checking with relation to regular types, containment, or equivalence.

  16. Single ion counting with a MCP (microchannel plate) detector

    Energy Technology Data Exchange (ETDEWEB)

    Tawara, Hiroko; Sasaki, Shinichi; Miyajima, Mitsuhiro [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan); Shibamura, Eido

    1996-07-01

    In this study, a single-ion-counting method using alpha-particle-impact ionization of Ar atoms is demonstrated and the preliminary {epsilon}{sub mcp} for Ar ions with incident energies of 3 to 4.7 keV is determined. The single-ion counting by the MCP is aimed to be performed under experimental conditions as follows: (1) A signal from the MCP is reasonably identified as incidence of single Ar-ion. (2) The counting rate of Ar ions is less than 1 s{sup -1}. (3) The incident Ar ions are not focused on a small part of an active area of the MCP, namely, {epsilon}{sub mcp} is determined with respect to the whole active area of the MCP. So far, any absolute detection efficiency has not been reported under these conditions. (J.P.N.)

  17. Kids Count Data Sheet, 2000.

    Science.gov (United States)

    Annie E. Casey Foundation, Baltimore, MD.

    Data from the 50 United States are listed for 1997 from Kids Count in an effort to track state-by-state the status of children in the United States and to secure better futures for all children. Data include percent low birth weight babies; infant mortality rate; child death rate; rate of teen deaths by accident, homicide, and suicide; teen birth…

  18. Vote Counting as Mathematical Proof

    DEFF Research Database (Denmark)

    Schürmann, Carsten; Pattinson, Dirk

    then consists of a sequence (or tree) of rule applications and provides an independently checkable certificate of the validity of the result. This reduces the need to trust, or otherwise verify, the correctness of the vote counting software once the certificate has been validated. Using a rule...

  19. Verbal Counting in Bilingual Contexts

    Science.gov (United States)

    Donevska-Todorova, Ana

    2015-01-01

    Informal experiences in mathematics often include playful competitions among young children in counting numbers in as many as possible different languages. Can these enjoyable experiences result with excellence in the formal processes of education? This article discusses connections between mathematical achievements and natural languages within…

  20. Rational Formulation of Alternative Fuels using QSPR Methods: Application to Jet Fuels Développement d’un outil d’aide à la formulation des carburants alternatifs utilisant des méthodes QSPR (Quantitative Structure Property Relationship: application aux carburéacteurs

    Directory of Open Access Journals (Sweden)

    Saldana D.A.

    2013-06-01

    Full Text Available Alternative fuels are a promising solution for road transport but also for aircraft. In the aviation field, a huge amount of work has been done in the past years with the approval to use up to 50 % by volume of SPK (Synthetic Paraffinic Kerosene in blends with conventional fossil Jet A-1. SPK are Fischer-Tropsch (FT fuels but also Hydroprocessed Esters and Fatty Acids (HEFA. However, these alternative fuels can have different chemical properties depending on the process used for their production. These properties include normal to iso paraffin ratio, carbon chain length and level of branching. R&D studies of alternative fuels are based on the evaluation of products coming from identified production processes. However, it appears that a better way of studying them could be firstly to determine the best chemical composition regarding aviation problems and secondly to find the best process and finishing process in order to obtain such a product. The objective of this work is to design a tool that aims to guide the future formulation of alternative fuels for aviation through the prediction of targeted physical properties. Thus, it is proposed to apply a methodology that identifies relationships between the structure and properties of a molecule (QSPR for Quantitative Structure Property Relationship, with the aim of establishing predictive models. These models will be built for hydrocarbons (normal and iso paraffins, naphthenes, aromatics, etc. and oxygenated compounds (esters and alcohols. For aviation, oxygenated compounds are not considered as a drop-in fuel. It could be seen as a disruptive solution in a long term view. There are concerns with oxygenates in aviation that are covered in this paper such as the flash point but others such as the energetic content, the water affinity that are not taken into account in this paper. The properties currently studied are flash point, cetane number, density and viscosity. The data sets will contain data

  1. Atomic energy

    CERN Multimedia

    1996-01-01

    Interviews following the 1991 co-operation Agreement between the Department of Atomic Energy (DAE) of the Government of India and the European Organization for Nuclear Research (CERN) concerning the participation in the Large Hadron Collider Project (LHC) . With Chidambaram, R, Chairman, Atomic Energy Commission and Secretary, Department of Atomic Energy, Department of Atomic Energy (DAE) of the Government of India and Professor Llewellyn-Smith, Christopher H, Director-General, CERN.

  2. Atom chips

    CERN Document Server

    Reichel, Jakob

    2010-01-01

    This book provides a stimulating and multifaceted picture of a rapidly developing field. The first part reviews fundamentals of atom chip research in tutorial style, while subsequent parts focus on the topics of atom-surface interaction, coherence on atom chips, and possible future directions of atom chip research. The articles are written by leading researchers in the field in their characteristic and individual styles.

  3. Counting Statistics in Nanoscale Junctions

    OpenAIRE

    Liu, Yu-Shen; Chen, Yu-Chang

    2010-01-01

    We present first-principles calculations for moments of the current up to the third order in atomic-scale junctions. The quantum correlations of the current are calculated using the current operator in terms of the wave functions obtained self-consistently within the static density-functional theory. We investigate the relationships of the conductance, the second, and the third moment of the current for carbon atom chains of various lengths bridging two metal electrodes in the linear and nonl...

  4. Bayesian Kernel Mixtures for Counts.

    Science.gov (United States)

    Canale, Antonio; Dunson, David B

    2011-12-01

    Although Bayesian nonparametric mixture models for continuous data are well developed, there is a limited literature on related approaches for count data. A common strategy is to use a mixture of Poissons, which unfortunately is quite restrictive in not accounting for distributions having variance less than the mean. Other approaches include mixing multinomials, which requires finite support, and using a Dirichlet process prior with a Poisson base measure, which does not allow smooth deviations from the Poisson. As a broad class of alternative models, we propose to use nonparametric mixtures of rounded continuous kernels. An efficient Gibbs sampler is developed for posterior computation, and a simulation study is performed to assess performance. Focusing on the rounded Gaussian case, we generalize the modeling framework to account for multivariate count data, joint modeling with continuous and categorical variables, and other complications. The methods are illustrated through applications to a developmental toxicity study and marketing data. This article has supplementary material online. PMID:22523437

  5. Reference counting for reversible languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2014-01-01

    Modern programming languages and operating systems use heap memory that allows allocation and deallocation of memory to be decoupled, so they don't follow a stack discipline. Axelsen and Glück have presented a reversible heap manager where allocation and deallocation are each other's logical...... inverses: Freeing a block of memory is done by running the allocation procedure backwards. Axelsen and Glück use this heap manager to sketch implementation of a simple reversible functional language where pattern matching a constructor is the inverse of construction, so pattern-matching implies...... deallocation. This requires the language to be linear: A pointer can not be copied and it can only be eliminated by deallocating the node to which it points. We overcome this limitation by adding reference counts to nodes: Copying a pointer to a node increases the reference count of the node and eliminating...

  6. Atomic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Safronova, M. S. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Mitroy, J. [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Clark, Charles W. [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20899-8410 (United States); Kozlov, M. G. [Petersburg Nuclear Physics Institute, Gatchina 188300 (Russian Federation)

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  7. Atomic Physics

    CERN Document Server

    Foot, Christopher J

    2007-01-01

    This text will thoroughly update the existing literature on atomic physics. Intended to accompany an advanced undergraduate course in atomic physics, the book will lead the students up to the latest advances and the applications to Bose-Einstein Condensation of atoms, matter-wave inter-ferometry and quantum computing with trapped ions. The elementary atomic physics covered in the early chapters should be accessible to undergraduates when they are first introduced to the subject. To complement. the usual quantum mechanical treatment of atomic structure the book strongly emphasizes the experimen

  8. Atomic polarizabilities

    International Nuclear Information System (INIS)

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed

  9. Bayesian Kernel Mixtures for Counts

    OpenAIRE

    Canale, Antonio; David B Dunson

    2011-01-01

    Although Bayesian nonparametric mixture models for continuous data are well developed, there is a limited literature on related approaches for count data. A common strategy is to use a mixture of Poissons, which unfortunately is quite restrictive in not accounting for distributions having variance less than the mean. Other approaches include mixing multinomials, which requires finite support, and using a Dirichlet process prior with a Poisson base measure, which does not allow smooth deviatio...

  10. Radioactivity determination by coincidence counting

    International Nuclear Information System (INIS)

    The 4 π β-γ coincidence counting equipment used in the Lucas Heights radioisotope standards laboratory for international comparisons is described in detail. A radioactivity standard is a method rather than a material object; as such it can be specified clearly only by discussing fully the setting-up and operation of one particular set of equipment. This manual is written for persons who are setting up such equipment for the first time

  11. 10481 Abstracts Collection -- Computational Counting

    OpenAIRE

    Bürgisser, Peter; Goldberg, Leslie Ann; Jerrum, Mark

    2011-01-01

    From November 28 to December 3 2010, the Dagstuhl Seminar 10481 ``Computational Counting'' was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in ge...

  12. Constraint Satisfaction with Counting Quantifiers

    CERN Document Server

    Madelaine, Florent; Stacho, Juraj

    2011-01-01

    We initiate the study of constraint satisfaction problems (CSPs) in the presence of counting quantifiers, which may be seen as variants of CSPs in the mould of quantified CSPs (QCSPs). We show that a single counting quantifier strictly between exists^1:=exists and exists^n:=forall (the domain being of size n) already affords the maximal possible complexity of QCSPs (which have both exists and forall), being Pspace-complete for a suitably chosen template. Next, we focus on the complexity of subsets of counting quantifiers on clique and cycle templates. For cycles we give a full trichotomy -- all such problems are in L, NP-complete or Pspace-complete. For cliques we come close to a similar trichotomy, but one case remains outstanding. Afterwards, we consider the generalisation of CSPs in which we augment the extant quantifier exists^1:=exists with the quantifier exists^j (j not 1). Such a CSP is already NP-hard on non-bipartite graph templates. We explore the situation of this generalised CSP on bipartite templ...

  13. Optimal design for count data

    Directory of Open Access Journals (Sweden)

    Muritala Abdulkabir

    2015-01-01

    Full Text Available Optimal designs for generalized linear models (GLM have received increasing attention in recent years. Most of this research focuses on binary data model. This research extends to count data models. The aim and objectives of this research work to determine the appropriate generalized linear model (GLM that is suitable for count data and identify a design that is best according to statistical optimality criteria, the data use for this research work are simulated data from R statistical package using uniform distribution with sample size 300. The simplest distribution use for modeling count data is Poisson distribution, quasi Poisson were carried out to test for over dispersion in the Poisson regression model and the formal way of dealing with over dispersion is negative binomial regression model, thus AIC was use to compare the two models, the Poisson regression model shows the best with minimum AIC. Furthermore optimal design were carried out using the optimality criterion that is the A and D optimality criterion, using design efficiency to compare the two (2 designs the optimality criterion with the highest efficiency is the best, thus D optimality criterion shows the best design.

  14. Monitoring Milk Somatic Cell Counts

    Directory of Open Access Journals (Sweden)

    Gheorghe Şteţca

    2014-11-01

    Full Text Available The presence of somatic cells in milk is a widely disputed issue in milk production sector. The somatic cell counts in raw milk are a marker for the specific cow diseases such as mastitis or swollen udder. The high level of somatic cells causes physical and chemical changes to milk composition and nutritional value, and as well to milk products. Also, the mastitic milk is not proper for human consumption due to its contribution to spreading of certain diseases and food poisoning. According to these effects, EU Regulations established the maximum threshold of admitted somatic cells in raw milk to 400000 cells / mL starting with 2014. The purpose of this study was carried out in order to examine the raw milk samples provided from small farms, industrial type farms and milk processing units. There are several ways to count somatic cells in milk but the reference accepted method is the microscopic method described by the SR EN ISO 13366-1/2008. Generally samples registered values in accordance with the admissible limit. By periodical monitoring of the somatic cell count, certain technological process issues are being avoided and consumer’s health ensured.

  15. Atom interferometry

    International Nuclear Information System (INIS)

    We will first present a development of the fundamental principles of atom interferometers. Next we will discuss a few of the various methods now available to split and recombine atomic De Broglie waves, with special emphasis on atom interferometers based on optical pulses. We will also be particularly concerned with high precision interferometers with long measurement times such those made with atomic fountains. The application of atom interferometry to the measurement of the acceleration due to gravity will be detailed. We will also develop the atom interferometry based on adiabatic transfer and we will apply it to the measurement of the photon recoil in the case of the Doppler shift of an atomic resonance caused by the momentum recoil from an absorbed photon. Finally the outlook of future developments will be given. (A.C.)

  16. Repeatability of differential goat bulk milk culture and associations with somatic cell count, total bacterial count, and standard plate count

    NARCIS (Netherlands)

    Koop, G.; Dik, N.; Nielen, M.; Lipman, L.J.A.

    2010-01-01

    The aims of this study were to assess how different bacterial groups in bulk milk are related to bulk milk somatic cell count (SCC), bulk milk total bacterial count (TBC), and bulk milk standard plate count (SPC) and to measure the repeatability of bulk milk culturing. On 53 Dutch dairy goat farms,

  17. Tallahatchie NWR - Landbird Point Counts in 2009

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Avian point counts were done in selected areas of mature forest on Tallahatchie Refuge in 2009. Report contains summary of avain point counts done in mature...

  18. Alaska Steller Sea Lion Pup Count Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This database contains counts of Steller sea lion pups on rookeries in Alaska made between 1961 and 2015. Pup counts are conducted in late June-July. Pups are...

  19. Counting spanning trees in graphs

    OpenAIRE

    Azarija, Jernej

    2012-01-01

    The history of counting the number of spanning trees dates back into the year 1842 in which the German mathematician Gustav Kirchhoff derived a relation between the number of spanning trees of a graph G (τ(G)) and the determinant of a specific submatrix associated with G. After this result many other related results followed. For example in 1889 the British mathematician A. Cayley showed that the complete graph on n nodes has nn−2 spanning trees.The function τ can nowadays be found in the fi...

  20. Counting Square-Free Numbers

    OpenAIRE

    Pawlewicz, Jakub

    2011-01-01

    The main topic of this contribution is the problem of counting square-free numbers not exceeding $n$. Before this work we were able to do it in time (Comparing to the Big-O notation, Soft-O ($\\softO$) ignores logarithmic factors) $\\softO(\\sqrt{n})$. Here, the algorithm with time complexity $\\softO(n^{2/5})$ and with memory complexity $\\softO(n^{1/5})$ is presented. Additionally, a parallel version is shown, which achieves full scalability. As of now the highest computed value was for $n=10^{1...

  1. Model Counting in Product Configuration

    CERN Document Server

    Kübler, Andreas; Küchlin, Wolfgang; 10.4204/EPTCS.29.5

    2010-01-01

    We describe how to use propositional model counting for a quantitative analysis of product configuration data. Our approach computes valuable meta information such as the total number of valid configurations or the relative frequency of components. This information can be used to assess the severity of documentation errors or to measure documentation quality. As an application example we show how we apply these methods to product documentation formulas of the Mercedes-Benz line of vehicles. In order to process these large formulas we developed and implemented a new model counter for non-CNF formulas. Our model counter can process formulas, whose CNF representations could not be processed up till now.

  2. Schroedinger atom

    International Nuclear Information System (INIS)

    Features of an electrodynamical interpretation suggested by Schroedinger for the wave function are discribed. According to this conception electron charges are continuously distributed all over the volume of an atomic system. The proof is given that classical electrodynamics keeps its action inside atom. Schroedinger's atom has been shown to be the only model in which electrones do not lose their energy for emission when they move around nucleus. A significance of the distributed electron charge self-field is estimated. Practical applications of this conception have been noted including the new trend in quantum electrodynamics. Experimental and theoretical corroborations of the atom model with a continuous electron charge are adduced

  3. Atomic physics

    International Nuclear Information System (INIS)

    Research activities in atomic physics at Lawrence Berkeley Laboratory during 1976 are described. Topics covered include: experiments on stored ions; test for parity violation in neutral weak currents; energy conservation and astrophysics; atomic absorption spectroscopy, atomic and molecular detectors; theoretical studies of quantum electrodynamics and high-z ions; atomic beam magnetic resonance; radiative decay from the 23Po,2 levels of helium-like argon; quenching of the metastable 2S/sub 1/2/ state of hydrogen-like argon in an external electric field; and lifetime of the 23Po level of helium-like krypton

  4. DC KIDS COUNT e-Databook Indicators

    Science.gov (United States)

    DC Action for Children, 2012

    2012-01-01

    This report presents indicators that are included in DC Action for Children's 2012 KIDS COUNT e-databook, their definitions and sources and the rationale for their selection. The indicators for DC KIDS COUNT represent a mix of traditional KIDS COUNT indicators of child well-being, such as the number of children living in poverty, and indicators of…

  5. Spectral CT with photon counting detectors

    International Nuclear Information System (INIS)

    Full text: Spectral computed tomography measures the energy specific attenu ation of an object across the X-ray spectrum. The technique improves soft tissue contrast and enables functional imaging which are two important limitations of conventional CT. Clinical application under investigation include: (I) atheroma characterisation to determine plaque stability by assessment of iron content within the atheroma; (2) functional imaging using atomic substitution, such as K1Rb; (2) function imaging with gold nano-particles to asses membrane permeability. To perform spectral CT we have constructed a microCT, dubbed MARS. that incorporates the Medipix family of energy selective photon counting detectors. The X-ray source produces a standard broad (Bremsstrahlung) X-ray spectrum. For imaging, the X-rays pass through the object and energy selective projection images are obtained over a range of angles. The Medipix detectors have several modes of operation including, one energy per exposure and up to eight energies per exposure. Reconstruction and material differentiation has been performed using both quantitative and qualitative methods. The technology can be translated to human imaging by tiling the detectors in 2 x N arrays enabling an active area of 28 mm x I m. Both GaAs and CdTe are sensors have been tested enabling accept able conversation efficiency up to around 100 key.

  6. Counting efficiencies by liquid scintillation counting. Single isomeric transitions

    International Nuclear Information System (INIS)

    In this work we present liquid scintillation counting efficiency tables for several radionuclides with single isomeric transitions, in which electron conversion and gamma emission processes are competitive. We study the radionuclides: ''58m CO, ''77mSE, ''79mBR, ''87mSR,''89mY,''93mNB,''103mRh, ''107mAG, ''109mAG, ''113mIn, ''131mXe; ''133mXe,''135mBa, ''167mEr, for two different scintillators, Ultima-Gold and Insta-Gel. We consider volumes of 10 and 15 mL for Ultima gold, and 15 mL for Insta-Gel

  7. How much do women count if they not counted?

    Directory of Open Access Journals (Sweden)

    Federica Taddia

    2006-01-01

    Full Text Available The condition of women throughout the world is marked by countless injustices and violations of the most fundamental rights established by the Universal Declaration of human rights and every culture is potentially prone to commit discrimination against women in various forms. Women are worse fed, more exposed to physical violence, more exposed to diseases and less educated; they have less access to, or are excluded from, vocational training paths; they are the most vulnerable among prisoners of conscience, refugees and immigrants and the least considered within ethnic minorities; from their very childhood, women are humiliated, undernourished, sold, raped and killed; their work is generally less paid compared to men’s work and in some countries they are victims of forced marriages. Such condition is the result of old traditions that implicit gender-differentiated education has long promoted through cultural models based on theories, practices and policies marked by discrimination and structured differentially for men and women. Within these cultural models, the basic educational institutions have played and still play a major role in perpetuating such traditions. Nevertheless, if we want to overcome inequalities and provide women with empowerment, we have to start right from the educational institutions and in particular from school, through the adoption of an intercultural approach to education: an approach based on active pedagogy and on methods of analysis, exchange and enhancement typical of socio-educational animation. The intercultural approach to education is attentive to promote the realisation of each individual and the dignity and right of everyone to express himself/herself in his/her own way. Such an approach will give women the opportunity to become actual agents of collective change and to get the strength and wellbeing necessary to count and be counted as human beings entitled to freedom and equality, and to have access to all

  8. Atomic physics

    CERN Document Server

    Born, Max

    1989-01-01

    The Nobel Laureate's brilliant exposition of the kinetic theory of gases, elementary particles, the nuclear atom, wave-corpuscles, atomic structure and spectral lines, electron spin and Pauli's principle, quantum statistics, molecular structure and nuclear physics. Over 40 appendices, a bibliography, numerous figures and graphs.

  9. Complete blood count and retinal vessel calibers.

    Directory of Open Access Journals (Sweden)

    Gerald Liew

    Full Text Available OBJECTIVE: The influence of hematological indices such as complete blood count on microcirculation is poorly understood. Retinal microvasculature can be directly visualized and vessel calibers are associated with a range of ocular and systemic diseases. We examined the association of complete blood count with retinal vessel calibers. METHODS: Cross-sectional population-based Blue Mountains Eye Study, n = 3009, aged 49+ years. Complete blood count was measured from fasting blood samples taken at baseline examination, 1992-4. Retinal arteriolar and venular calibers were measured from digitized retinal photographs using a validated semi-automated computer program. RESULTS: All analyses adjusted for age, sex, systolic blood pressure, diabetes, smoking and fellow vessel caliber. Higher hematocrit, white cell count and platelet count were associated with narrower arteriolar caliber (p = 0.02, 0.03 and 0.001 respectively, while higher hemoglobin, hematocrit, red cell count, white cell count and platelet count were associated with wider venular caliber (p<0.0001 for all. Each quintile increase in hematocrit, white cell count and platelet count was associated with approximately 0.5 µm narrower arteriolar caliber; whereas each quintile increase in all of the complete blood count components was associated with approximately 1-2 µm wider venular caliber. CONCLUSIONS: These associations show that elevated levels of hematological indices can have adverse effects on the microcirculation.

  10. Counting hypermaps by Egorychev's method

    Science.gov (United States)

    Mednykh, Alexander; Nedela, Roman

    2015-11-01

    The aim of this paper is to find explicit formulae for the number of rooted hypermaps with a given number of darts on an orientable surface of genus g≤ 3 . Such formulae were obtained earlier for g=0 and g=1 by Walsh and Arquès respectively. We first employ the Egorychev's method of counting combinatorial sums to obtain a new version of the Arquès formula for genus g=1 . Then we apply the same approach to get new results for genus g=2,3 . We could do it due to recent results by Giorgetti, Walsh, and Kazarian, Zograf who derived two different, but equivalent, forms of the generating functions for the number of hypermaps of genus two and three.

  11. Counting solutions from finite samplings.

    Science.gov (United States)

    Huang, Haiping; Zhou, Haijun

    2012-02-01

    We formulate the solution counting problem within the framework of the inverse Ising problem and use fast belief propagation equations to estimate the entropy whose value provides an estimate of the true one. We test this idea on both diluted models [random 2-SAT (2-satisfiability) and 3-SAT problems] and a fully connected model (binary perceptron), and show that when the constraint density is small, this estimate can be very close to the true value. The information stored by the salamander retina under the natural movie stimuli can also be estimated, and our result is consistent with that obtained by the Monte Carlo method. Of particular significance is that the sizes of other metastable states for this real neuronal network are predicted. PMID:22463290

  12. Sediment varve counting with PIXE

    International Nuclear Information System (INIS)

    The feasibility of the particle induced X-ray emission (PIXE) technique for varve counting of vertically taken marine and lacustrine sediments was studied aiming at its possible use as a dating procedure by observing the yearly variation of the constituent elements. The samples were impregnated with a low viscosity epoxy resin to obtain slabs with preserved layered structure suitable for the PIXE analyses. PIXE-spectra were taken as a function of depth distance and the normalized X-ray peak area variations were determined. Especially, concentration changes of silicon and iron were found to be clear. Due to the employed sample preparation technique the observed chlorine concentration corresponds to the amount of water in the initial sample. Maximum chlorine concentration appeared at positions where the Si and Fe concentrations were near minimum. By plotting the Si/Cl or Fe/Cl peak area ratios, an even more distinct position dependent variation was noted. (author)

  13. Photon counting compressive depth mapping

    CERN Document Server

    Howland, Gregory A; Ware, Matthew R; Howell, John C

    2013-01-01

    We demonstrate a compressed sensing, photon counting lidar system based on the single-pixel camera. Our technique recovers both depth and intensity maps from a single under-sampled set of incoherent, linear projections of a scene of interest at ultra-low light levels around 0.5 picowatts. Only two-dimensional reconstructions are required to image a three-dimensional scene. We demonstrate intensity imaging and depth mapping at 256 x 256 pixel transverse resolution with acquisition times as short as 3 seconds. We also show novelty filtering, reconstructing only the difference between two instances of a scene. Finally, we acquire 32 x 32 pixel real-time video for three-dimensional object tracking at 14 frames-per-second.

  14. Counting Square-Free Numbers

    CERN Document Server

    Pawlewicz, Jakub

    2011-01-01

    The main topic of this contribution is the problem of counting square-free numbers not exceeding $n$. Before this work we were able to do it in time (Comparing to the Big-O notation, Soft-O ($\\softO$) ignores logarithmic factors) $\\softO(\\sqrt{n})$. Here, the algorithm with time complexity $\\softO(n^{2/5})$ and with memory complexity $\\softO(n^{1/5})$ is presented. Additionally, a parallel version is shown, which achieves full scalability. As of now the highest computed value was for $n=10^{17}$. Using our implementation we were able to calculate the value for $n=10^{36}$ on a cluster.

  15. Counting paths with Schur transitions

    CERN Document Server

    Diaz, Pablo; Veliz-Osorio, Alvaro

    2016-01-01

    In this work we explore the structure of the branching graph of the unitary group using Schur transitions. We find that these transitions suggest a new combinatorial expression for counting paths in the branching graph. This formula, which is valid for any rank of the unitary group, reproduces known asymptotic results. We proceed to establish the general validity of this expression by a formal proof. The form of this equation strongly hints towards a quantum generalization. Thus, we introduce a notion of quantum relative dimension and subject it to the appropriate consistency tests. This new quantity finds its natural environment in the context of RCFTs and fractional statistics; where the already established notion of quantum dimension has proven to be of great physical importance.

  16. Model Counting in Product Configuration

    Directory of Open Access Journals (Sweden)

    Andreas Kübler

    2010-07-01

    Full Text Available We describe how to use propositional model counting for a quantitative analysis of product configuration data. Our approach computes valuable meta information such as the total number of valid configurations or the relative frequency of components. This information can be used to assess the severity of documentation errors or to measure documentation quality. As an application example we show how we apply these methods to product documentation formulas of the Mercedes-Benz line of vehicles. In order to process these large formulas we developed and implemented a new model counter for non-CNF formulas. Our model counter can process formulas, whose CNF representations could not be processed up till now.

  17. Diprotonation process of meso-tetraphenylporphyrin derivatives designed for Photodynamic Therapy of cancers: From Multivariate Curve Resolution to predictive QSPR modeling

    International Nuclear Information System (INIS)

    Highlights: → Diprotonation of 17 meso-tetraphenylporphyrin derivatives. → MCR-ALS resolution of multi-component mixtures. → Determination of stepwise protonation constants. → Prediction of protonation constants from ET-State indices. - Abstract: Tetrapyrrole rings possess four nitrogen atoms, two of which act as Broendsted bases in acidic media. The two protonation steps occur on a close pH range, particularly in the case of meso-tetraphenylporphyrin (TPP) derivatives. If the cause of this phenomenon is well known - a protonation-induced distortion of the porphyrin ring - data on stepwise protonation constants and on electronic absorption spectra of monoprotonated TPPs are sparse. A multivariate approach has been systematically applied to a series of glycoconjugated and hydroxylated TPPs, potential anticancer drugs usable in Photodynamic Therapy. The dual purpose was determination of protonation constants and linking substitution with basicity. Hard-modeling version of MCR-ALS (Multivariate Curve Resolution Alternating Least Squares) has given access to spectra and distribution profile of pure components. Spectra of monoprotonated species (H3TPP+) in solution resemble those of diprotonated species (H4TPP2+), mainly differing by a slight blue-shift of bands. Overlap of H3TPP+ and H4TPP2+ spectra reinforces the difficulty to evidence an intermediate form only present in low relative abundance. Depending on macrocycle substitution, pK values ranged from 3.5 ± 0.1 to 5.1 ± 0.1 for the first protonation and from 3.2 ± 0.2 to 4.9 ± 0.1 for the second one. Inner nitrogens' basicity is affected by position, number and nature of peripheral substituents depending on their electrodonating character. pK values have been used to establish a predictive Multiple Linear Regression (MLR) model, relying on atom-type electrotopological indices. This model accurately describes our results and should be applied to new TPP derivatives in a drug-design perspective.

  18. Diprotonation process of meso-tetraphenylporphyrin derivatives designed for photodynamic therapy of cancers: from multivariate curve resolution to predictive QSPR modeling.

    Science.gov (United States)

    Chauvin, Benoît; Kasselouri, Athena; Chaminade, Pierre; Quiameso, Rita; Nicolis, Ioannis; Maillard, Philippe; Prognon, Patrice

    2011-10-31

    Tetrapyrrole rings possess four nitrogen atoms, two of which act as Bröndsted bases in acidic media. The two protonation steps occur on a close pH range, particularly in the case of meso-tetraphenylporphyrin (TPP) derivatives. If the cause of this phenomenon is well known--a protonation-induced distortion of the porphyrin ring--data on stepwise protonation constants and on electronic absorption spectra of monoprotonated TPPs are sparse. A multivariate approach has been systematically applied to a series of glycoconjugated and hydroxylated TPPs, potential anticancer drugs usable in Photodynamic Therapy. The dual purpose was determination of protonation constants and linking substitution with basicity. Hard-modeling version of MCR-ALS (Multivariate Curve Resolution Alternating Least Squares) has given access to spectra and distribution profile of pure components. Spectra of monoprotonated species (H(3)TPP(+)) in solution resemble those of diprotonated species (H(4)TPP(2+)), mainly differing by a slight blue-shift of bands. Overlap of H(3)TPP(+) and H(4)TPP(2+) spectra reinforces the difficulty to evidence an intermediate form only present in low relative abundance. Depending on macrocycle substitution, pK values ranged from 3.5±0.1 to 5.1±0.1 for the first protonation and from 3.2±0.2 to 4.9±0.1 for the second one. Inner nitrogens' basicity is affected by position, number and nature of peripheral substituents depending on their electrodonating character. pK values have been used to establish a predictive Multiple Linear Regression (MLR) model, relying on atom-type electrotopological indices. This model accurately describes our results and should be applied to new TPP derivatives in a drug-design perspective. PMID:21962373

  19. Probabilities and energies to obtain the counting efficiency of electron-capture nuclides, KLMN model

    International Nuclear Information System (INIS)

    An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electron-capture in the counting efficiency when the atomic number of the nuclide is high

  20. Very high count rate gamma spectroscopy

    International Nuclear Information System (INIS)

    Recent improvements in the electronics that amplify and analyze gamma photon-induced pulses have made it possible for HPGe coaxial detectors to accept input rates of one-million, one-MeV gamma photons-per-second and still provide the spectroscopist with spectra that can be analyzed. Data are presented that illustrate peak area variances and changes in counting uncertainty statistics due to the greatly extended count rate range. Software algorithms are presented that allow gain shift and peak resolution to be adjusted automatically on a sample-by-sample basis. Relationships are developed between integrated count rate and the variances of full energy photon peak area and counting uncertainty when using the real time correction mode of pulse processing. Finally, the results of integrating hardware and software into a system are used to illustrate that quantitative gamma spectroscopy over counting rates of one- to one-million counts-per-second are achievable

  1. Complete Blood Count and Retinal Vessel Calibers

    OpenAIRE

    Liew, Gerald; Wang, Jie Jin; Rochtchina, Elena; Wong, Tien Yin; Mitchell, Paul

    2014-01-01

    Objective The influence of hematological indices such as complete blood count on microcirculation is poorly understood. Retinal microvasculature can be directly visualized and vessel calibers are associated with a range of ocular and systemic diseases. We examined the association of complete blood count with retinal vessel calibers. Methods Cross-sectional population-based Blue Mountains Eye Study, n = 3009, aged 49+ years. Complete blood count was measured from fasting blood samples taken at...

  2. Vector perturbations of galaxy number counts

    CERN Document Server

    Durrer, Ruth

    2016-01-01

    We derive the contribution to relativistic galaxy number count fluctuations from vector and tensor perturbations within linear perturbation theory. Our result is consistent with the the relativistic corrections to number counts due to scalar perturbation, where the Bardeen potentials are replaced with line-of-sight projection of vector and tensor quantities. Since vector and tensor perturbations do not lead to density fluctuations the standard density term in the number counts is absent. We apply our results to vector perturbations which are induced from scalar perturbations at second order and give numerical estimates of their contributions to the power spectrum of relativistic galaxy number counts.

  3. Diprotonation process of meso-tetraphenylporphyrin derivatives designed for Photodynamic Therapy of cancers: From Multivariate Curve Resolution to predictive QSPR modeling

    Energy Technology Data Exchange (ETDEWEB)

    Chauvin, Benoit, E-mail: benoit.chauvin@u-psud.fr [Univ. Paris-Sud, EA 4041, IFR 141, Faculte de Pharmacie, F-92296 Chatenay-Malabry (France); Institut Curie, UMR 176 CNRS, Centre Universitaire, Univ Paris-Sud, F-91405 Orsay (France); Kasselouri, Athena; Chaminade, Pierre; Quiameso, Rita [Univ. Paris-Sud, EA 4041, IFR 141, Faculte de Pharmacie, F-92296 Chatenay-Malabry (France); Nicolis, Ioannis [Laboratoire de Biomathematiques et Informatique, Departement de Sante publique et biostatistiques et EA 4466, Faculte de Pharmacie, Universite Paris Descartes, 4, avenue de l' Observatoire, 75270 Paris cedex 06 (France); Maillard, Philippe [Institut Curie, UMR 176 CNRS, Centre Universitaire, Univ Paris-Sud, F-91405 Orsay (France); Prognon, Patrice [Univ. Paris-Sud, EA 4041, IFR 141, Faculte de Pharmacie, F-92296 Chatenay-Malabry (France)

    2011-10-31

    Highlights: {yields} Diprotonation of 17 meso-tetraphenylporphyrin derivatives. {yields} MCR-ALS resolution of multi-component mixtures. {yields} Determination of stepwise protonation constants. {yields} Prediction of protonation constants from ET-State indices. - Abstract: Tetrapyrrole rings possess four nitrogen atoms, two of which act as Broendsted bases in acidic media. The two protonation steps occur on a close pH range, particularly in the case of meso-tetraphenylporphyrin (TPP) derivatives. If the cause of this phenomenon is well known - a protonation-induced distortion of the porphyrin ring - data on stepwise protonation constants and on electronic absorption spectra of monoprotonated TPPs are sparse. A multivariate approach has been systematically applied to a series of glycoconjugated and hydroxylated TPPs, potential anticancer drugs usable in Photodynamic Therapy. The dual purpose was determination of protonation constants and linking substitution with basicity. Hard-modeling version of MCR-ALS (Multivariate Curve Resolution Alternating Least Squares) has given access to spectra and distribution profile of pure components. Spectra of monoprotonated species (H{sub 3}TPP{sup +}) in solution resemble those of diprotonated species (H{sub 4}TPP{sup 2+}), mainly differing by a slight blue-shift of bands. Overlap of H{sub 3}TPP{sup +} and H{sub 4}TPP{sup 2+} spectra reinforces the difficulty to evidence an intermediate form only present in low relative abundance. Depending on macrocycle substitution, pK values ranged from 3.5 {+-} 0.1 to 5.1 {+-} 0.1 for the first protonation and from 3.2 {+-} 0.2 to 4.9 {+-} 0.1 for the second one. Inner nitrogens' basicity is affected by position, number and nature of peripheral substituents depending on their electrodonating character. pK values have been used to establish a predictive Multiple Linear Regression (MLR) model, relying on atom-type electrotopological indices. This model accurately describes our results and

  4. Particle-counting statistics of time- and space-dependent fields

    Science.gov (United States)

    Braungardt, Sibylle; Rodríguez, Mirta; Glauber, Roy J.; Lewenstein, Maciej

    2012-03-01

    The counting statistics give insight into the properties of quantum states of light and other quantum states of matter such as ultracold atoms or electrons. The theoretical description of photon counting was derived in the 1960s and was extended to massive particles more recently. Typically, the interaction between each particle and the detector is assumed to be limited to short time intervals, and the probability of counting particles in one interval is independent of the measurements in previous intervals. There has been some effort to describe particle counting as a continuous measurement, where the detector and the field to be counted interact continuously. However, the formalism based on continuous measurements does not provide a formula applicable to general time- and space-dependent fields. In our work, we derive a fully time- and space-dependent description of the counting process for linear quantum many-body systems, taking into account the back-action of the detector on the field. We apply our formalism to an expanding Bose-Einstein condensate of ultracold atoms, and show that it describes the process correctly, whereas the standard approach gives unphysical results in some limits. The example illustrates that, in certain situations, the back-action of the detector cannot be neglected and has to be included in the description.

  5. Atomic secrecy

    International Nuclear Information System (INIS)

    An article, The H-Bomb Secret: How We Got It, Why We're Telling It, by Howard Morland was to be published in The Progressive magazine in February, 1979. The government, after learning of the author's and the editors' intention to publish the article and failing to persuade them to voluntarily delete about 20% of the text and all of the diagrams showing how an H-bomb works, requested a court injunction against publication. Acting under the Atomic Energy Act of 1954, US District Court Judge Robert W. Warren granted the government's request on March 26. Events dealing with the case are discussed in this publication. Section 1, Progressive Hydrogen Bomb Case, is discussed under the following: Court Order Blocking Magazine Report; Origins of the Howard Morland Article; Author's Motives, Defense of Publication; and Government Arguments Against Disclosure. Section 2, Access to Atomic Data Since 1939, contains information on need for secrecy during World War II; 1946 Atomic Energy Act and its effects; Soviet A-Bomb and the US H-Bomb; and consequences of 1954 Atomic Energy Act. Section 3, Disputed Need for Atomic Secrecy, contains papers entitled: Lack of Studies on H-Bomb Proliferation; Administration's Position on H-Bombs; and National Security Needs vs Free Press

  6. Applications of resonance ionization spectroscopy to ultralow-level counting and mass spectroscopy

    International Nuclear Information System (INIS)

    The ability to directly detect a daughter atom, using resonance ionization spectroscopy, in delayed time coincidence with the decay of a parent species promises to drastically reduce the background in low-level counting experiments. Resonance ionization can also be used as an ion source for a mass spectrometer system that is capable of discriminating between isobars

  7. Whole-body counting 1990

    International Nuclear Information System (INIS)

    In order to determine the doses from radiocesium in foods after the Chernobyl accident, four groups were chosen in 1987. Two groups, presumed to have a large consumption of food items with a high radiocesium content, were selected. These were Lapp reindeer breeders from central parts of Norway, and hunters a.o. from the municipality of Oeystre Slidre. Two other groups were randomly selected, one from the municipality of Sel, and one from Oslo. The persons in these two groups were presumed to have an average diet. The fall-out in Sel was fairly large (100 kBq/m2), whereas in Oslo the fall-out level was low (2 kBq/m2). The persons in each group were monitored once a year with whole-body counters, and in connection with these countings dietary surveys were preformed. In 1990 the Sel-group and the Lapps in central parts of Norway were followed. Average whole-body activity in each group is compared to earlier years's results, and an average yearly effective dose equivalent is computed. The Sel-group has an average whole-body activity of 2800 Bq for men, and 690 Bq for women. Compared to earlier years, there is a steady but slow decrease in whole-body activities. Yearly dose is calculated to 0.06 mSv for 1990. The Lapps in central parts of Norway have an average whole-body content of 23800 Bq for men and 13600 Bq for women. This results in an average yearly dose of 0.9 mSv for the individuals in the group. Compared to earlier years, the Lapp group show a decrease in whole-body contents since 1988. This decrease is larger among men than women. 5 refs., 8 figs., 6 tabs

  8. Atomic theories

    CERN Document Server

    Loring, FH

    2014-01-01

    Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec

  9. Counting results for sparse pseudorandom hypergraphs I

    OpenAIRE

    Kohayakawa, Yoshiharu; Mota, Guilherme O.; Schacht, Mathias; Taraz, Anusch

    2016-01-01

    We establish a so-called counting lemma that allows embeddings of certain linear uniform hypergraphs into sparse pseudorandom hypergraphs, generalizing a result for graphs [Embedding graphs with bounded degree in sparse pseudorandom graphs, Israel J. Math. 139 (2004), 93-137]. Applications of our result are presented in the companion paper [Counting results for sparse pseudorandom hypergraphs II].

  10. Lazy reference counting for the Microgrid

    NARCIS (Netherlands)

    R. Poss; C. Grelck; S. Herhut; S.-B. Scholz

    2012-01-01

    This papers revisits non-deferred reference counting, a common technique to ensure that potentially shared large heap objects can be reused safely when they are both input and output to computations. Traditionally, thread-safe reference counting exploit implicit memory-based communication of counter

  11. A simple bivariate count data regression model

    OpenAIRE

    Shiferaw Gurmu; John Elder

    2007-01-01

    This paper develops a simple bivariate count data regression model in which dependence between count variables is introduced by means of stochastically related unobserved heterogeneity components. Unlike existing commonly used bivariate models, we obtain a computationally simple closed form of the model with an unrestricted correlation pattern.

  12. Is It Counting, or Is It Adding?

    Science.gov (United States)

    Eisenhardt, Sara; Fisher, Molly H.; Thomas, Jonathan; Schack, Edna O.; Tassell, Janet; Yoder, Margaret

    2014-01-01

    The Common Core State Standards for Mathematics (CCSSI 2010) expect second grade students to "fluently add and subtract within 20 using mental strategies" (2.OA.B.2). Most children begin with number word sequences and counting approximations and then develop greater skill with counting. But do all teachers really understand how this…

  13. 2013 Kids Count in Colorado! Community Matters

    Science.gov (United States)

    Colorado Children's Campaign, 2013

    2013-01-01

    "Kids Count in Colorado!" is an annual publication of the Children's Campaign, providing state and county level data on child well-being factors including child health, education, and economic status. Since its first release 20 years ago, "Kids Count in Colorado!" has become the most trusted source for data and information on…

  14. Mediation Analysis for Count and Zero-Inflated Count Data without Sequential Ignorability

    OpenAIRE

    Guo, Zijian; Small, Dylan S.; Gansky, Stuart A.; Cheng, Jing

    2016-01-01

    Count or zero-inflated count data are common in many studies. Most existing mediation analysis approaches for count data assume sequential ignorability of the mediator. This is often not plausible because the mediator is not randomized so that there are unmeasured confounders associated with the mediator and the outcome. In this paper, we consider causal methods based on instrumental variable (IV) approaches for mediation analysis for count data possibly with a lot of zeros that do not requir...

  15. CORRELATION BETWEEN CLINICAL PROFILE, CD 4 COUNT AND TOTAL LYMPHOCYTE COUNT IN HIV INFECTED PERSONS

    OpenAIRE

    Keshava; Manjunath

    2014-01-01

    BACKGROUND & OBJECTIVES: HIV infection can be monitored by laboratory and clinical markers of disease progression. In the absence of CD 4 count , the use of Total Lymphocyte Count has been advocated to predict CD 4 count and to stage HIV disease. This study was undertaken to show whether the TLC accurately predicts a low CD 4 count in HIV infected persons and its clinical correlation. METHODOLOGY: The data for the study was collected from HIV positive inpatien...

  16. Atoms as Qed bound atoms

    International Nuclear Information System (INIS)

    The relevance of Quantum Electrodynamics (Qed) in contemporary atomic structure theory is reviewed. Recent experimental advances allow both the production of heavy ions of high charge as well as the measurement of atomic properties with a precision never achieved before. The description of heavy atoms with few electrons via the successive incorporation of one, two, etcetera photons in a rigorous manner and within the bound state Furry representation of Qed is technically feasible. For many-electron atoms the many-body (correlation) effects are very important and it is practically impossible to evaluate all the relevant Feynman diagrams to the required accuracy. Thus, it is necessary to develop a theoretical scheme in which the radiative and nonradiative effects are taken into account in an effective way making emphasis in electronic correlation. Preserving gauge invariance, and avoiding both continuum dissolution and variational collapse are basic problems that must be solved when using effective potential methods and finite-basis representations of them. In this context, we shall discuss advances and problems in the description of atoms as Qed bound states. (Author)

  17. Dying Dyons Don't Count

    CERN Document Server

    Cheng, Miranda C N

    2007-01-01

    The dyonic 1/4-BPS states in 4D string theory with N=4 spacetime supersymmetry are counted by a Siegel modular form. The pole structure of the modular form leads to a contour dependence in the counting formula obscuring its duality invariance. We exhibit the relation between this ambiguity and the (dis-)appearance of bound states of 1/2-BPS configurations. Using this insight we propose a precise moduli-dependent contour prescription for the counting formula. We then show that the degeneracies are duality-invariant and are correctly adjusted at the walls of marginal stability to account for the (dis-)appearance of the two-centered bound states. Especially, for large black holes none of these bound states exists at the attractor point and none of these ambiguous poles contributes to the counting formula. Using this fact we also propose a second, moduli-independent contour which counts the "immortal dyons" that are stable everywhere.

  18. Prediction of auto-ignition temperatures of hydrocarbons by neural network based on atom-type electrotopological-state indices

    International Nuclear Information System (INIS)

    A quantitative structure-property relationship (QSPR) model was constructed to predict the auto-ignition temperature (AIT) of 118 hydrocarbons by means of artificial neural network (ANN). Atom-type electrotopological-state indices were used as molecular structure descriptors which combined together both electronic and topological characteristics of the analyzed molecules. The typical back-propagation (BP) neural network was employed for fitting the possible non-linear relationship existed between the atom-type electrotopological-state indices and AIT. The dataset of 118 hydrocarbons was randomly divided into a training set (60), a validation set (16) and a testing set (42). The optimal condition of the neural network was obtained by adjusting various parameters by trial-and-error. Simulated with the final optimum BP neural network [16-8-1], the results show that most of the predicted AIT values are in good agreement with the experimental data, with the average absolute error being 21.6 deg. C, and the root mean square error (RMS) being 31.09 for the testing set, which are superior to those obtained by multiple linear regression analysis and traditional group contribution method. The model proposed can be used not only to reveal the quantitative relation between AIT and molecular structures of hydrocarbons, but also to predict the AIT values of hydrocarbons for chemical engineering

  19. Neutrinos, atoms and gravity

    International Nuclear Information System (INIS)

    A interesting overview of ongoing developments in neutrino physics and recent advances in atomic and optical physics and in gravitation emerged from the recent 'Moriond' Workshop on Perspectives in Neutrinos, Atomic Physics and Gravitation Theory, held from January 30 to February 6 at Villars sur Ollon in the Swiss Alps. Neutrino physics is a Moriond tradition, and the Workshop began with presentations of new measurements of the tritium beta spectrum by the Livermore and Mainz groups, setting limits on the mass of electron (anti)neutrino of 8 eV and 7.2 eV respectively. It is puzzling that the five most advanced experiments setting upper limits on the electron (anti)neutrino mass (Livermore, Los Alamos, Mainz, Tokyo and Zurich) report negative best-fit values for the square of the neutrino mass, with a weighted average of -59 ±177 ± 26 eV2. This corresponds to an excess of counts near the tritium endpoint, rather than a deficit which would indicate a nonzero neutrino mass. Gerry Stephenson presented a possible explanation, invoking a very light (or massless) scalar boson coupled only to neutrinos. Perhaps more plausibly, a systematic effect may be the cause, and further studies are underway. Nonetheless, the limits are unlikely to change significantly, and the results exclude electron neutrinos as the possible dominant component of dark matter. The solar neutrino problem persists

  20. Practical Gamma Counting of Unirradiated Uranium-235

    International Nuclear Information System (INIS)

    During the fabrication of reactor fuel elements it is necessary to have assurance regarding the accuracy of the fabricator's uranium assignment within the specified tolerances. Destructive analysis of random samples is both expensive and time-consuming. Where the uranium-bearing components are suitable for gamma counting, a non-destructive method of assay can be used with greater efficiency and equal accuracy. The particular method described was used for checking fuel cores of nominal 30 wt.% enriched uranium in aluminium measuring about two inches square by 0.080 in. and 0.160 in. thick. The equipment was a basic Nal scintillation counter equipped with a single-channel analyser. The analyser, however, was operated with a very wide window covering both the 90-keV and 184-keV peaks characteristic of uranium-235. In practice, the threshold level acid the window opening, were adjusted to give the optimum maximum count rate as indicated by a ratemeter. The counting of a fuel core was then performed with the Nal crystal essentially unshielded and located several inches above the fuel core. The counting time was adjusted to yield a total count in the range of 105 to 106 in order to minimize the counting error. Effects due to variations in the counting geometry and to non-uniform uranium distribution were minimized by the relatively large separation of the crystal from the fuel core. Effects due to shifting of analyser window were minimized by use of a wide opening. To compensate for possible non-uniform uranium distribution through the thickness of a fuel core, each core was counted on both sides. The total count obtained in this manner was directly proportioned to the uranium-235 content of the fuel core. In application, the counting equipment was set up in the fabricator's plant and a number of production fuel cores were counted. The plotting of the total counts against the fabricator's uranium-235 assignment revealed an unexpected error in the fabricator's system

  1. Linear operating region in the ozone dial photon counting system

    Science.gov (United States)

    Andrawis, Madeleine

    1995-01-01

    Ozone is a relatively unstable molecule found in Earth's atmosphere. An ozone molecule is made up of three atoms of oxygen. Depending on where ozone resides, it can protect or harm life on Earth. High in the atmosphere, about 15 miles up, ozone acts as a shield to protect Earth's surface from the sun's harmful ultraviolet radiation. Without this shield, we would be more susceptible to skin cancer, cataracts, and impaired immune systems. Closer to Earth, in the air we breathe, ozone is a harmful pollutant that causes damage to lung tissue and plants. Since the early 1980's, airborne lidar systems have been used for making measurements of ozone. The differential absorption lidar (DIAL) technique is used in the remote measurement of O3. This system allows the O3 to be measured as function of the range in the atmosphere. Two frequency-doubled Nd:YAG lasers are used to pump tunable dye lasers. The lasers are operating at 289 nm for the DIAL on-line wavelength of O3, and the other one is operated at 300 nm for the off-line wavelength. The DIAL wavelengths are produced in sequential laser pulses with a time separation of 300 micro s. The backscattered laser energy is collected by telescopes and measured using photon counting systems. The photon counting system measures the light signal by making use of the photon nature of light. The output pulse from the Photo-Multiplier Tube (PE), caused by a photon striking the PMT photo-cathode, is amplified and passed to a pulse height discriminator. The peak value of the pulse is compared to a reference voltage (discrimination level). If the pulse amplitude exceeds the discrimination level, the discriminator generates a standard pulse which is counted by the digital counter. Non-linearity in the system is caused by the overlapping of pulses and the finite response time of the electronics. At low count rates one expects the system to register one event for each output pulse from the PMT corresponding to a photon incident upon the

  2. Detection of single atoms by resonance ionization spectroscopy

    International Nuclear Information System (INIS)

    Rutherford's idea for counting individual atoms can, in principle, be implemented for nearly any type of atom, whether stable or radioactive, by using methods of resonance ionization. With the technique of resonance ionization spectroscopy (RIS), a laser is tuned to a wavelength that will promote a valence electron in a Z-selected atom to an excited level. Additional resonance or non-resonance photoabsorption steps are used to achieve nearly 100% ionization efficiencies. Hence, the RIS process can be saturated for the Z-selected atoms: and because detectors are available for counting either single electrons or positive ions, one-atom detection is possible. Some examples of one-atom detection are given, including that of the noble gases, to show complementarity with accelerator mass spectrometry AMS methods. For instance, the detection of 81Kr by using RIS has interesting applications for solar-neutrino research, ice-cap dating, and groundwater dating. (author)

  3. Detection of single atoms by resonance ionization spectroscopy

    International Nuclear Information System (INIS)

    Rutherford's idea for counting individual atoms can, in principle, be implemented for nearly any type of atom, whether stable or radioactive, by using methods of resonance ionization. With the RIS technique, a laser is tuned to a wavelength which will promote a valence electron in a Z-selected atom to an excited level. Additional resonance or nonresonance photoabsorption steps are used to achieve nearly 100% ionization efficiencies. Hence, the RIS process can be saturated for the Z-selected atoms; and since detectors are available for counting either single electrons or positive ions, one-atom detection is possible. Some examples are given of one-atom detection, including that of the noble gases, in order to show complementarity with AMS methods. For instance, the detection of 81Kr using RIS has interesting applications for solar neutrino research, ice-cap dating, and groundwater dating. 39 refs., 7 figs., 2 tabs

  4. An Adaptive Smoother for Counting Measurements

    International Nuclear Information System (INIS)

    Counting measurements associated with nuclear instruments are tricky to carry out due to the stochastic process of the radioactivity. Indeed events counting have to be processed and filtered in order to display a stable count rate value and to allow variations monitoring in the measured activity. Smoothers (as the moving average) are adjusted by a time constant defined as a compromise between stability and response time. A new approach has been developed and consists in improving the response time while maintaining count rate stability. It uses the combination of a smoother together with a detection filter. A memory of counting data is processed to calculate several count rate estimates using several integration times. These estimates are then sorted into the memory from short to long integration times. A measurement position, in terms of integration time, is then chosen into this memory after a detection test. An inhomogeneity into the Poisson counting process is detected by comparison between current position estimate and the other estimates contained into the memory in respect with the associated statistical variance calculated with homogeneous assumption. The measurement position (historical time) and the ability to forget an obsolete data or to keep in memory a useful data are managed using the detection test result. The proposed smoother is then an adaptive and a learning algorithm allowing an optimization of the response time while maintaining measurement counting stability and converging efficiently to the best counting estimate after an effective change in activity. This algorithm has also the specificity to be low recursive and thus easily embedded into DSP electronics based on FPGA or micro-controllers meeting 'real life' time requirements. (authors)

  5. B Counting at BaBar

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Grant Duncan

    2008-12-16

    In this thesis we examine the method of counting B{bar B} events produced in the BABAR experiment. The original method was proposed in 2000, but improvements to track reconstruction and our understanding of the detector since that date make it appropriate to revisit the B Counting method. We propose a new set of cuts designed to minimize the sensitivity to time-varying backgrounds. We find the new method counts B{bar B} events with an associated systematic uncertainty of {+-} 0.6%.

  6. Blood leucocyte count in the human fetus.

    OpenAIRE

    Davies, N P; Buggins, A G; Snijders, R J; Jenkins, E; Layton, D. M.; Nicolaides, K H

    1992-01-01

    Total and differential leucocyte counts were measured in cord blood samples obtained by cordocentesis (n = 316) or at elective caesarean section (n = 11) from normal fetuses of between 18 and 40 weeks' gestation. The total fetal leucocyte count increased exponentially from 2.8 x 10(9)/l at 18 weeks to 11.8 x 10(9)/l at term. The lymphocyte and monocyte counts increased linearly and the number of neutrophils increased exponentially from a mean value of 0.2 x 10(9)/l at 18 weeks to 0.8 x 10(9)/...

  7. Mourning Dove Call-count Survey

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Mourning Dove (Zenaida macroura) Call-Count Survey was developed to provide an index to population size and to detect annual changes in mourning dove breeding...

  8. Liquid scintillation counting of novel radionuclides

    International Nuclear Information System (INIS)

    The theoretical background of counting radionuclides in liquid scintillators is presented. The effects of quenching and finite scintillator size are briefly described and the theory is justified by an experimental comparison between 55Fe and 3H in which all facets of the theory are important. Counting efficiencies for other nuclides decaying by 100% electron capture are calculated and compared with efficiencies for the β emitters 3H, 14C and 36Cl. Also included are comments on the special problems associated with counting plutonium in biological materials. The essential conclusion is that in order to improve the technique and avoid unnecessary pitfalls it is necessary to have a sound understanding of the underlying theory of liquid scintillation counting

  9. CoC Housing Inventory Count Reports

    Data.gov (United States)

    Department of Housing and Urban Development — Continuum of Care (CoC) Homeless Assistance Programs Housing Inventory Count Reports are a snapshot of a CoC’s housing inventory, available at the national and...

  10. Four square mile survey pair count instructions

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This standard operating procedure (SOP) provides guidance for conducting bird pair count measurements on wetlands for the HAPETs Four-Square-Mile survey. This set...

  11. Furbearer track count index testing and development

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Indices of abundance can be useful in monitoring furbearer populations where actual counts of individual animals are difficult. I sampled marten and snowshoe hare...

  12. Taxonomic counts of cognition in the wild

    OpenAIRE

    Lefebvre, Louis

    2010-01-01

    In 1985, Kummer & Goodall pleaded for an ecology of intelligence and proposed that innovations might be a good way to measure cognition in the wild. Counts of innovation per taxonomic group are now available in hundreds of avian and primate species, as are counts of tactical deception, tool use and social learning. Robust evidence suggests that innovation rate and its neural correlates allow birds and mammals to cope better with environmental change. The positive correlations between taxonomi...

  13. A Generic Multivariate Distribution for Counting Data

    OpenAIRE

    Capistrán, Marcos; Christen, J. Andrés

    2011-01-01

    Motivated by the need, in some Bayesian likelihood free inference problems, of imputing a multivariate counting distribution based on its vector of means and variance-covariance matrix, we define a generic multivariate discrete distribution. Based on blending the Binomial, Poisson and Negative-Binomial distributions, and using a normal multivariate copula, the required distribution is defined. This distribution tends to the Multivariate Normal for large counts and has an approximate pmf versi...

  14. How to count an introduction to combinatorics

    CERN Document Server

    Allenby, RBJT

    2010-01-01

    What's It All About? What Is Combinatorics? Classic Problems What You Need to Know Are You Sitting Comfortably? Permutations and Combinations The Combinatorial Approach Permutations CombinationsApplications to Probability Problems The Multinomial Theorem Permutations and Cycles Occupancy Problems Counting the Solutions of Equations New Problems from Old A ""Reduction"" Theorem for the Stirling Numbers The Inclusion-Exclusion Principle Double Counting Derangements A Formula for the Stirling NumbersStirling and Catalan Numbers Stirling Numbers Permutations and Stirling Numbers Catalan Numbers Pa

  15. SIS Detectors for Terahertz Photon Counting System

    Science.gov (United States)

    Ezawa, Hajime; Matsuo, Hiroshi; Ukibe, Masahiro; Fujii, Go; Shiki, Shigetomo

    2016-07-01

    An Intensity interferometer with photon counting detector is a candidate to realize a THz interferometer for astronomical observations. We have demonstrated that synthesis imaging is possible even with intensity interferometers. An SIS junction (or STJ) with low leakage current of 1 pA is a suitable device for photon counting detectors. Readout circuit utilizing FETs with low gate leakage, low gate capacitance, and fast response is discussed.

  16. Photon counting statistics using a digital oscilloscope

    OpenAIRE

    Ricci, M. L. Martinez; Mazzaferri, J.; Bragas, A. V.; Martinez, O. E.

    2006-01-01

    We present a photon counting experiment designed for an undergraduate physics laboratory. The statistics of the number of photons of a pseudo-thermal light source is studied in two limiting cases: much longer and much shorter than the coherence time, giving Poisson and Bose-Einstein distributions, respectively. The experiment can be done in a reasonable time using a digital oscilloscope without the need of counting boards. The use of the oscilloscope has the advantage of allowing the storage ...

  17. Differential expression analysis for sequence count data

    OpenAIRE

    Anders, Simon; Huber, Wolfgang

    2010-01-01

    High-throughput sequencing assays such as RNA-Seq, ChIP-Seq or barcode counting provide quantitative readouts in the form of count data. To infer differential signal in such data correctly and with good statistical power, estimation of data variability throughout the dynamic range and a suitable error model are required. We propose a method based on the negative binomial distribution, with variance and mean linked by local regression and present an implementation, DESeq, as an R/Bioconductor ...

  18. Remote system for counting of nuclear pulses

    International Nuclear Information System (INIS)

    In this work, it is describe technically the remote system for counting of nuclear pulses, an integral system of the project radiological monitoring in a petroleum distillation tower. The system acquires the counting of incident nuclear particles in a nuclear detector which process this information and send it in serial form, using the RS-485 toward a remote receiver, which can be a Personal computer or any other device capable to interpret the communication protocol. (Author)

  19. Fetal leucocyte count in rhesus disease.

    OpenAIRE

    Davies, N P; Buggins, A G; Snijders, R J; Noble, P N; Layton, D. M.; Nicolaides, K H

    1992-01-01

    The effect of fetal anaemia on the total and differential leucocyte counts was studied by examining blood samples obtained by cordocentesis from 177 previously untransfused rhesus affected fetuses at 17-36 weeks' gestation. The mean fetal total leucocyte, lymphocyte, and monocyte counts were significantly lower than the corresponding values in normal controls and there were significant associations between the decrease in these cells and the degree of fetal anaemia. Possible mechanisms for le...

  20. The Complexity of Approximately Counting Stable Matchings

    CERN Document Server

    Chebolu, Prasad; Martin, Russell

    2010-01-01

    We investigate the complexity of approximately counting stable matchings in the $k$-attribute model, where the preference lists are determined by dot products of "preference vectors" with "attribute vectors", or by Euclidean distances between "preference points" and "attribute points". Irving and Leather proved that counting the number of stable matchings in the general case is $#P$-complete. Counting the number of stable matchings is reducible to counting the number of downsets in a (related) partial order and is interreducible, in an approximation-preserving sense, to a class of problems that includes counting the number of independent sets in a bipartite graph ($#BIS$). It is conjectured that no FPRAS exists for this class of problems. We show this approximation-preserving interreducibilty remains even in the restricted $k$-attribute setting when $k \\geq 3$ (dot products) or $k \\geq 2$ (Euclidean distances). Finally, we show it is easy to count the number of stable matchings in the 1-attribute dot-product ...

  1. Optimal Private Halfspace Counting via Discrepancy

    CERN Document Server

    Muthukrishnan, S

    2012-01-01

    A range counting problem is specified by a set $P$ of size $|P| = n$ of points in $\\mathbb{R}^d$, an integer weight $x_p$ associated to each point $p \\in P$, and a range space ${\\cal R} \\subseteq 2^{P}$. Given a query range $R \\in {\\cal R}$, the target output is $R(\\vec{x}) = \\sum_{p \\in R}{x_p}$. Range counting for different range spaces is a central problem in Computational Geometry. We study $(\\epsilon, \\delta)$-differentially private algorithms for range counting. Our main results are for the range space given by hyperplanes, that is, the halfspace counting problem. We present an $(\\epsilon, \\delta)$-differentially private algorithm for halfspace counting in $d$ dimensions which achieves $O(n^{1-1/d})$ average squared error. This contrasts with the $\\Omega(n)$ lower bound established by the classical result of Dinur and Nissim [PODS 2003] for arbitrary subset counting queries. We also show a matching lower bound on average squared error for any $(\\epsilon, \\delta)$-differentially private algorithm for hal...

  2. Factors affecting leukocyte count in healthy adults.

    Science.gov (United States)

    Carel, R S; Eviatar, J

    1985-09-01

    The relationships between white blood cell (WBC) count, smoking, and other health variables were determined among 35,000 apparently healthy men and women. The effect of smoking on the WBC count was greater than that of all other variables. The leukocyte level and the variance in WBC count values increased with increased smoking intensity. The relationship between smoking intensity and leukocyte level is expressed quantitatively by the following regression equation: WBC (10(3)/mm3) = 7.1 + 0.05(SM), where SM has seven values according to the smoking level. Multiple regression analysis with additional variables other than smoking did not much improve the predictive value of the equation. The effect of smoking on WBC count could be only partially explained by an inflammatory process, e.g., chronic bronchitis. Relationships of statistical significance (but mostly with r values of less than 0.10) were found between WBC count and the following variables: hemoglobin, heart rate, weight (or Quetelet index), cholesterol, uric acid, creatinine, sex, ethnic origin, systolic blood pressure, height, blood sugar, and diastolic blood pressure. The normal WBC count range for smokers differs from that of nonsmokers and is shifted to the right according to the smoking level. This may have both a diagnostic and prognostic significance in different clinical settings. PMID:4070192

  3. Exotic atoms

    International Nuclear Information System (INIS)

    The experiments use a solid hydrogen layer to form muonic hydrogen isotopes that escape into vacuum. The method relies on transfer of the muon from protium to either a deuteron or a triton. The resulting muonic deuterium or muonic tritium will not immediately thermalize because of the very low elastic cross sections, and may be emitted from the surface of the layer. Measurements which detect decay electrons, muonic x-rays, and fusion products have been used to study the processes. A target has been constructed which exploits muonic atom emission in order to learn more about the energy dependence of transfer and muon molecular formation

  4. Atomic Clocks

    Science.gov (United States)

    Wynands, Robert

    Time is a strange thing. On the one hand it is arguably the most inaccessible physical phenomenon of all: both in that it is impossible to manipulate or modify—for all we know—and in that even after thousands of years mankind's philosophers still have not found a fully satisfying way to understand it. On the other hand, no other quantity can be measured with greater precision. Today's atomic clocks allow us to reproduce the length of the second as the SI unit of time with an uncertainty of a few parts in 1016—orders of magnitude better than any other quantity. In a sense, one can say [1

  5. Single atom measurement and atomic manipulation using atomic force microscope

    International Nuclear Information System (INIS)

    This paper explains studies to measure atomic force as the force linking an atom and atom, using an atomic force microscope (AFM). First, it describes the principle and device configuration of AFM, and as an example of the atomic force measurement of Si atoms on the surface of Si(111)-(7x7), it describes the technique to measure atomic force using AFM, as well as the uncertainty of probe tip against atomic force. In addition, it describes the following items on the measurement results of chemical bonding force: (1) chemical bonding force vs physical force and chemical bonding force vs current on the surface of Si(111)-(7x7), (2) chemical bonding force and element dependence on the surface of Si/Sn(111)-(√3x√3), (3) atomic manipulation based on AMF, and (4) relationship between atomic manipulation and the size of chemical bonding force with a probe. (A.O.)

  6. Atom Skimmers and Atom Lasers Utilizing Them

    Science.gov (United States)

    Hulet, Randall; Tollett, Jeff; Franke, Kurt; Moss, Steve; Sackett, Charles; Gerton, Jordan; Ghaffari, Bita; McAlexander, W.; Strecker, K.; Homan, D.

    2005-01-01

    Atom skimmers are devices that act as low-pass velocity filters for atoms in thermal atomic beams. An atom skimmer operating in conjunction with a suitable thermal atomic-beam source (e.g., an oven in which cesium is heated) can serve as a source of slow atoms for a magneto-optical trap or other apparatus in an atomic-physics experiment. Phenomena that are studied in such apparatuses include Bose-Einstein condensation of atomic gases, spectra of trapped atoms, and collisions of slowly moving atoms. An atom skimmer includes a curved, low-thermal-conduction tube that leads from the outlet of a thermal atomic-beam source to the inlet of a magneto-optical trap or other device in which the selected low-velocity atoms are to be used. Permanent rare-earth magnets are placed around the tube in a yoke of high-magnetic-permeability material to establish a quadrupole or octupole magnetic field leading from the source to the trap. The atoms are attracted to the locus of minimum magnetic-field intensity in the middle of the tube, and the gradient of the magnetic field provides centripetal force that guides the atoms around the curve along the axis of the tube. The threshold velocity for guiding is dictated by the gradient of the magnetic field and the radius of curvature of the tube. Atoms moving at lesser velocities are successfully guided; faster atoms strike the tube wall and are lost from the beam.

  7. Adaptive and Approximate Orthogonal Range Counting

    DEFF Research Database (Denmark)

    Chan, Timothy M.; Wilkinson, Bryan Thomas

    2013-01-01

    ]. •We give an O(n loglog n)-space data structure for approximate 2-D orthogonal range counting that can compute a (1+δ)-factor approximation to the count in O(loglog n) time for any fixed constant δ>0. Again, our bounds match the state of the art for the 2-D orthogonal range emptiness problem. •Lastly......Close Abstract We present three new results on one of the most basic problems in geometric data structures, 2-D orthogonal range counting. All the results are in the w-bit word RAM model. •It is well known that there are linear-space data structures for 2-D orthogonal range counting with worst......-case optimal query time O(log_w n). We give an O(n loglog n)-space adaptive data structure that improves the query time to O(loglog n + log_w k), where k is the output count. When k=O(1), our bounds match the state of the art for the 2-D orthogonal range emptiness problem [Chan, Larsen, and Pătraşcu, SoCG 2011...

  8. Genetic regulatory networks that count to 3.

    Science.gov (United States)

    Lehmann, Malte; Sneppen, Kim

    2013-07-21

    Sensing a graded input and differentiating between its different levels is at the core of many developmental decisions. Here, we want to examine how this can be realized for a simple system. We model gene regulatory circuits that reach distinct states when setting the underlying gene copy number to 1, 2 and 3. This distinction can be considered as counting the copy number. We explore different circuits that allow for counting and keeping memory of the count after resetting the copy number to 1. For this purpose, we sample different architectures and parameters, only considering circuits that contain repressive links, which we model by Michaelis-Menten terms. Interestingly, we find that counting to 3 does not require a hierarchy in Hill coefficients, in contrast to counting to 2, which is known from lambda phage. Furthermore, we find two main circuit architectures: one design also found in the vertebrate neural tube in a development governed by the sonic hedgehog morphogen and the more robust design of a repressilator supplemented with a weak repressilator acting in the opposite direction. PMID:23567648

  9. Delta count-rate monitoring system

    International Nuclear Information System (INIS)

    A need for a more effective way to rapidly search for gamma-ray contamination over large areas led to the design and construction of a very sensitive gamma detection system. The delta count-rate monitoring system was installed in a four-wheel-drive van instrumented for environmental surveillance and accident response. The system consists of four main sections: (1) two scintillation detectors, (2) high-voltage power supply amplifier and single-channel analyzer, (3) delta count-rate monitor, and (4) count-rate meter and recorder. The van's 6.5-kW generator powers the standard nuclear instrument modular design system. The two detectors are mounted in the rear corners of the van and can be run singly or jointly. A solid-state bar-graph count-rate meter mounted on the dashboard can be read easily by both the driver and passenger. A solid-state strip chart recorder shows trends and provides a permanent record of the data. An audible alarm is sounded at the delta monitor and at the dashboard count-rate meter if a detected radiation level exceeds the set background level by a predetermined amount

  10. Correlation between Total Lymphocyte Count, Hemoglobin, Hematocrit and CD4 Count in HIV/AIDS Patients

    Directory of Open Access Journals (Sweden)

    Alavi S.M

    2009-04-01

    Full Text Available Lymphocyte CD4+count, a standard laboratory test for staging of HIV infection, is expensive and unavailable in resource-restricted countries. Total lymphocyte count (TLC and hemoglobin (Hb are recommended as simple & inexpensive surrogates. The aim of this study was to assess the correlation, sensitivity and predictive power of these parameters as substitutes for CD4 count. One hundred HIV patients enrolled in this analytic descriptive study in Ahvaz, a city in the South of Iran, from 2005 to 2006. They were tested for CD4 count, TLC, Hb, and hematocrit (Hct. The cutoffs were determined as: 200 cells/µL, 1200 cells/µL, 12 g/dl and 30%, respectively. We used Sys Max SE 9500 for CBC and Flow cytometry for CD4 count. The correlation coefficient established correlation between values. Sensitivity, specificity and positive predictive values were calculated. 2 females (%2 and 98 males (%98 of the mean age of 32±5 years were studied. 87 cases (%87 were IV drug users, the majority having a history of imprisonment. The mean CD4 count, TLC, Hb and Hct were 279±225, 2102±1250, 10.7±2.4 and 30.4±9.0, respectively. A strong correlation was observed between CD4 count and TLC (R = 0.645, P = 0.001, but no correlation was seen between CD4 count and Hb or Hct (R= 0.451, P=0.056 and R= 0.375, P=0.816 respectively. This study shows that TLC is a suitable surrogate marker for CD4 count. Hb and Hct are of limited value in predicting CD4 counts and should not be substituted for CD4counts.

  11. Counting Processes for Retail Default Modeling

    DEFF Research Database (Denmark)

    Kiefer, Nicholas Maximilian; Larson, C. Erik

    Counting processes provide a very flexible framework for modeling discrete events occurring over time. Estimation and interpretation is easy, and links to more familiar approaches are at hand. The key is to think of data as "event histories," a record of times of switching between states...... in a discrete state space. In a simple case, the states could be default/non-default; in other models relevant for credit modeling the states could be credit scores or payment status (30 dpd, 60 dpd, etc.). Here we focus on the use of stochastic counting processes for mortgage default modeling, using data...... by these different methods? We address this question in the counting process framework. In fact, MI is associated with lower d...

  12. Multi-window counting of radioactivity

    International Nuclear Information System (INIS)

    In counting of radioactivity, using for example gas proportional (GP) or liquid scintillation (LS) counters, one can set up two or more electronic windows, which can measure two or more radiation components. In this work, we derived general equations for n-window counting in matrix notation, including mutual crosstalk between the windows using both the ratio (not normalized) and the fraction (normalized) methods. A solution for n radiation components is presented. For the two-window measurements, we report complete statistical analysis of the results including propagation of all uncertainties. The decision-level and the detection-limit equations were derived including crosstalk correction, uncertainties of the variables, Gaussian continuity correction, interference correction, and the overdispersion correction. Numerical verifications of the two-window systems are presented, including conditions for the detection of a minor component in the presence of a major component. In addition, limited experimental verifications of the two-window systems using LS counting are reported.

  13. Efficient statistical mapping of avian count data

    Science.gov (United States)

    Royle, J. Andrew; Wikle, C.K.

    2005-01-01

    We develop a spatial modeling framework for count data that is efficient to implement in high-dimensional prediction problems. We consider spectral parameterizations for the spatially varying mean of a Poisson model. The spectral parameterization of the spatial process is very computationally efficient, enabling effective estimation and prediction in large problems using Markov chain Monte Carlo techniques. We apply this model to creating avian relative abundance maps from North American Breeding Bird Survey (BBS) data. Variation in the ability of observers to count birds is modeled as spatially independent noise, resulting in over-dispersion relative to the Poisson assumption. This approach represents an improvement over existing approaches used for spatial modeling of BBS data which are either inefficient for continental scale modeling and prediction or fail to accommodate important distributional features of count data thus leading to inaccurate accounting of prediction uncertainty.

  14. Metal ion levels and lymphocyte counts

    DEFF Research Database (Denmark)

    Penny, Jeannette Ø; Varmarken, Jens-Erik; Ovesen, Ole;

    2013-01-01

    BACKGROUND AND PURPOSE: Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA) and...... investigated whether cobalt and chromium ions affected the lymphocyte counts. METHOD: In a randomized controlled trial, we followed 19 RHA patients and 19 THA patients. Lymphocyte subsets and chromium and cobalt ion concentrations were measured at baseline, at 8 weeks, at 6 months, and at 1 and 2 years....... RESULTS: The T-lymphocyte counts for both implant types declined over the 2-year period. This decline was statistically significant for CD3(+)CD8(+) in the THA group, with a regression coefficient of -0.04 × 10(9)cells/year (95% CI: -0.08 to -0.01). Regression analysis indicated a depressive effect of...

  15. Dark count rates in the STIS MAMA

    Science.gov (United States)

    Cox, Colin

    2013-06-01

    The dark count rates in the STIS MAMA detectors have been monitored. This report covers the period since the Servicing Mission 4 of May 2009. We find both long-term and short-term variations which for the NUV side we express as a function of date and temperature. The NUV dark rate has declined significantly from its surprisingly high initial rate of 0.014 counts/pixel/s that was seen immediately after SM4. By October, 2012 it had dropped to an average value of about 0.002 counts/pixel/sec The behavior and characteristics of the FUV dark rate remain very similar to that seen in 2004, prior to the STIS side-2 failure and subsequent repair.

  16. Whole body counting of radon daughters

    International Nuclear Information System (INIS)

    This paper reports on five adult males that were exposed for one hour to radon and radon daughter products in an exposure chamber and subsequently measured for radon daughter product activity in the chest region by whole body counting methods. The gamma-ray detection rate was approximated by a single exponential with a 35 minute half period, consistent with the physical decay of a mixture of RaB and RaC. About half of the deposited activity was associated with internal deposition and half with external deposition on clothing, skin and hair. The average counting rate from radon daughters on clothing was 10 times the average from skin and hair. Under as well as outer clothing contributed substantially to the counting rate. A strong correlation was found between internal and external deposition indicating that total activity provides a useful index of internal deposition

  17. CERN_DxCTA counting mode chip

    CERN Document Server

    Moraes, D; Nygård, E

    2008-01-01

    This ASIC is a counting mode front-end electronic optimized for the readout of CdZnTe/CdTe and silicon sensors, for possible use in applications where the flux of ionizing radiation is high. The chip is implemented in 0.25 μm CMOS technology. The circuit comprises 128 channels equipped with a transimpedance amplifier followed by a gain shaper stage with 21 ns peaking time, two discriminators and two 18-bit counters. The channel architecture is optimized for the detector characteristics in order to achieve the best energy resolution at counting rates of up to 5 M counts/second. The amplifier shows a linear sensitivity of 118 mV/fC and an equivalent noise charge of about 711 e−, for a detector capacitance of 5 pF. Complete evaluation of the circuit is presented using electronic pulses and pixel detectors.

  18. Bacterial colony counting by Convolutional Neural Networks.

    Science.gov (United States)

    Ferrari, Alessandro; Lombardi, Stefano; Signoroni, Alberto

    2015-08-01

    Counting bacterial colonies on microbiological culture plates is a time-consuming, error-prone, nevertheless fundamental task in microbiology. Computer vision based approaches can increase the efficiency and the reliability of the process, but accurate counting is challenging, due to the high degree of variability of agglomerated colonies. In this paper, we propose a solution which adopts Convolutional Neural Networks (CNN) for counting the number of colonies contained in confluent agglomerates, that scored an overall accuracy of the 92.8% on a large challenging dataset. The proposed CNN-based technique for estimating the cardinality of colony aggregates outperforms traditional image processing approaches, becoming a promising approach to many related applications. PMID:26738016

  19. Single Photon Counting UV Solar-Blind Detectors Using Silicon and III-Nitride Materials.

    Science.gov (United States)

    Nikzad, Shouleh; Hoenk, Michael; Jewell, April D; Hennessy, John J; Carver, Alexander G; Jones, Todd J; Goodsall, Timothy M; Hamden, Erika T; Suvarna, Puneet; Bulmer, J; Shahedipour-Sandvik, F; Charbon, Edoardo; Padmanabhan, Preethi; Hancock, Bruce; Bell, L Douglas

    2016-01-01

    Ultraviolet (UV) studies in astronomy, cosmology, planetary studies, biological and medical applications often require precision detection of faint objects and in many cases require photon-counting detection. We present an overview of two approaches for achieving photon counting in the UV. The first approach involves UV enhancement of photon-counting silicon detectors, including electron multiplying charge-coupled devices and avalanche photodiodes. The approach used here employs molecular beam epitaxy for delta doping and superlattice doping for surface passivation and high UV quantum efficiency. Additional UV enhancements include antireflection (AR) and solar-blind UV bandpass coatings prepared by atomic layer deposition. Quantum efficiency (QE) measurements show QE > 50% in the 100-300 nm range for detectors with simple AR coatings, and QE ≅ 80% at ~206 nm has been shown when more complex AR coatings are used. The second approach is based on avalanche photodiodes in III-nitride materials with high QE and intrinsic solar blindness. PMID:27338399

  20. Nutsedge Counts Predict Meloidogyne incognita Juvenile Counts in an Integrated Management System.

    Science.gov (United States)

    Ou, Zhining; Murray, Leigh; Thomas, Stephen H; Schroeder, Jill; Libbin, James

    2008-06-01

    The southern root-knot nematode (Meloidogyne incognita), yellow nutsedge (Cyperus esculentus) and purple nutsedge (Cyperus rotundus) are important pests in crops grown in the southern US. Management of the individual pests rather than the pest complex is often unsuccessful due to mutually beneficial pest interactions. In an integrated pest management scheme using alfalfa to suppress nutsedges and M. incognita, we evaluated quadratic polynomial regression models for prediction of the number of M. incognita J2 in soil samples as a function of yellow and purple nutsedge plant counts, squares of nutsedge counts and the cross-product between nutsedge counts . In May 2005, purple nutsedge plant count was a significant predictor of M. incognita count. In July and September 2005, counts of both nutsedges and the cross-product were significant predictors. In 2006, the second year of the alfalfa rotation, counts of all three species were reduced. As a likely consequence, the predictive relationship between nutsedges and M. incognita was not significant for May and July. In September 2006, purple nutsedge was a significant predictor of M. incognita. These results lead us to conclude that nutsedge plant counts in a field infested with the M. incognita-nutsedge pest complex can be used as a visual predictor of M. incognita J2 populations, unless the numbers of nutsedge plants and M. incognita are all very low. PMID:19259526

  1. Count-to-count time interval distribution analysis in a fast reactor

    International Nuclear Information System (INIS)

    The most important kinetic parameters have been measured at the zero power fast reactor CORAL-I by means of the reactor noise analysis in the time domain, using measurements of the count-to-count time intervals. (Author) 69 refs

  2. The lost castle of Count Rodrigo Gonzalez

    OpenAIRE

    Ehrlich, Michael

    2015-01-01

    This article suggests that a castle called Toron built in 1137 by Count Rodrigo of Lara, and granted to the Templar Order was in Summil, where remains of a Crusader castles are still visible (ca. 25 km from Ascalon, in south west Israel). This opinion opposes a consensual view that the castle built by Count Rodrigo was in Latrun, midway between Tel-Aviv and Jerusalem. This identifi cation is based on names’ similarity and on the universal opinion that Latrun was a Templar castle. In this arti...

  3. Interpretation of automated blood cell counts

    Directory of Open Access Journals (Sweden)

    Zühre Kaya

    2013-09-01

    Full Text Available Complete blood count (CBC tests are rapid, inexpensiveand universally available, and often aid primary clinicianswith decision making about patients with severaldisorders. Thus the rapid availability of the results of CBCcould provide considerable advantage for both patientsand clinicians. Furthermore, physicians can also avoidunnecessary peripheral blood smear examination usingCBC parameters. Many hematology analyzers, which enabledus simultaneously, measure several different CBCparameters, are available for early diagnosis. Herein theimpact of both pre and post analytic variations on the interpretationof the CBC results with case reports are reviewedin the light of the latest literature.Key words: Complete blood count, interpretation

  4. Advances in photon counting for bioluminescence

    Science.gov (United States)

    Ingle, Martin B.; Powell, Ralph

    1998-11-01

    Photon counting systems were originally developed for astronomy, initially by the astronomical community. However, a major application area is in the study of luminescent probes in living plants, fishes and cell cultures. For these applications, it has been necessary to develop camera system capability at very low light levels -- a few photons occasionally -- and also at reasonably high light levels to enable the systems to be focused and to collect quality images of the object under study. The paper presents new data on MTF at extremely low photon flux and conventional ICCD illumination, counting efficiency and dark noise as a function of temperature.

  5. One-atom detection and statistical studies with resonance ionization spectroscopy

    International Nuclear Information System (INIS)

    To learn how to take matter apart atom-by-atom and to count each atom according to its type, regardless of its initial chemical or physical state, is presumably a worthy goal in scientific research. The advent of the laser created real hope that these aspirations will be realized. The counting of atoms is not merely an intellectual exercise set apart from real-world applications. On the contrary, even though the capability is scarcely more than five years old, practical applications have been made in many fields of chemistry, physics, the environment, and industry. In this lecture we wish to review how the laser made possible the counting of atoms and how this capability has been put to use in situations where atoms are free to react chemically as they diffuse through a medium. Fluctuation phenomena and statistical mechanics can also be examined in these situations

  6. CORRELATION BETWEEN CLINICAL PROFILE, CD 4 COUNT AND TOTAL LYMPHOCYTE COUNT IN HIV INFECTED PERSONS

    Directory of Open Access Journals (Sweden)

    Keshava

    2014-01-01

    Full Text Available BACKGROUND & OBJECTIVES: HIV infection can be monitored by laboratory and clinical markers of disease progression. In the absence of CD 4 count , the use of Total Lymphocyte Count has been advocated to predict CD 4 count and to stage HIV disease. This study was undertaken to show whether the TLC accurately predicts a low CD 4 count in HIV infected persons and its clinical correlation. METHODOLOGY: The data for the study was collected from HIV positive inpatients and outpatients of KIMS Hospital , Bangalore fr om March 2004 to March 2006. A total 50 patients were subjected to clinical examination and relevant investigations including CD 4 Count and TLC. RESULTS: In our study , males (39 , outnumbered females (11. The major risk factor for HIV infection in these patients was unprotected , multiple sexual contacts. Fever , Anorexia , Weight loss , Lethargy , Cough , Diarrhea and Mouth ulcers were the common presenting symptoms. Tuberculosis , Chronic diarrhea , Oropharyngeal candidiasis were the most common opportunistic i nfections. Majority of the patients had CD 4 Count less than 350 cells/μl and were symptomatic. The Total Lymphocyte Counts of 1750 cells/μl and 2450 cells/μl correlated to CD 4 counts of 200 cells/μl and 350 cells/μl respectively. INTERPRETATION & CONCLUS ION: There was a highly significant correlation between CD 4 Count and Total Lymphocyte Count. TLC can be used as an effective laboratory tool to monitor disease progression in HIV infected persons where CD 4 is not available and in resource poor countries .

  7. Probabilities and energies to obtain the counting efficiency of electron-capture nuclides. KLMN model

    International Nuclear Information System (INIS)

    An intelligent computer program has been developed to obtain the mathematical formulae to compute the probabilities and reduced energies of the different atomic rearrangement pathways following electron-capture decay. Creation and annihilation operators for Auger and X processes have been introduced. Taking into account the symmetries associated with each process, 262 different pathways were obtained. This model allows us to obtain the influence of the M-electro capture in the counting efficiency when the atomic number of the nuclide is high. (Author)

  8. Axion Dark Matter Detection using Atomic Transitions

    CERN Document Server

    Sikivie, P

    2014-01-01

    Dark matter axions may cause transitions between atomic states that differ in energy by an amount equal to the axion mass. Such energy differences are conveniently tuned using the Zeeman effect. It is proposed to search for dark matter axions by cooling a kilogram-sized sample to milliKelvin temperatures and count axion induced transitions using laser techniques. This appears an appropriate approach to axion dark matter detection in the $10^{-4}$ eV mass range.

  9. Applications of resonance ionization spectroscopy to ultralow-level counting and mass spectroscopy

    International Nuclear Information System (INIS)

    In this paper it is shown that the ability to directly detect a daughter atom, using resonance ionization spectroscopy, in delayed time coincidence with the decay of a parent species promises to drastically reduce the background in low-level counting experiments. In addition, resonance ionization can also be used as an ion source for a mass spectrometer system that is capable of discriminating between isobars

  10. 7 CFR 51.1242 - Count per pound.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Count per pound. 51.1242 Section 51.1242 Agriculture... Standards for Cleaned Virginia Type Peanuts in the Shell Definitions § 51.1242 Count per pound. Count per pound means the number of peanuts in a pound. When determining the count per pound, one single...

  11. 20 CFR 418.3410 - Whose resources do we count?

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Whose resources do we count? 418.3410 Section... Subsidies Resources § 418.3410 Whose resources do we count? (a) We count your resources. We count the... subsidy if you are married and live with your spouse as of the month for which we determine...

  12. Project and construction of counting system for neutron probe

    International Nuclear Information System (INIS)

    A counting system was developed for coupling neutron probe aiming to register pulses produced by slow neutron interaction in the detector. The neutron probe consists of fast neutron source, thermal neutron detector, amplifier circuit and pulse counting circuit. The counting system is composed by counting circuit, timer and signal circuit. (M.C.K.)

  13. Differential white cell count by centrifugal microfluidics.

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Gregory Jon; Tentori, Augusto M.; Schaff, Ulrich Y.

    2010-07-01

    We present a method for counting white blood cells that is uniquely compatible with centrifugation based microfluidics. Blood is deposited on top of one or more layers of density media within a microfluidic disk. Spinning the disk causes the cell populations within whole blood to settle through the media, reaching an equilibrium based on the density of each cell type. Separation and fluorescence measurement of cell types stained with a DNA dye is demonstrated using this technique. The integrated signal from bands of fluorescent microspheres is shown to be proportional to their initial concentration in suspension. Among the current generation of medical diagnostics are devices based on the principle of centrifuging a CD sized disk functionalized with microfluidics. These portable 'lab on a disk' devices are capable of conducting multiple assays directly from a blood sample, embodied by platforms developed by Gyros, Samsung, and Abaxis. [1,2] However, no centrifugal platform to date includes a differential white blood cell count, which is an important metric complimentary to diagnostic assays. Measuring the differential white blood cell count (the relative fraction of granulocytes, lymphocytes, and monocytes) is a standard medical diagnostic technique useful for identifying sepsis, leukemia, AIDS, radiation exposure, and a host of other conditions that affect the immune system. Several methods exist for measuring the relative white blood cell count including flow cytometry, electrical impedance, and visual identification from a stained drop of blood under a microscope. However, none of these methods is easily incorporated into a centrifugal microfluidic diagnostic platform.

  14. Georgia Kids Count Factbook, 1998-99.

    Science.gov (United States)

    Georgians for Children, Atlanta, GA.

    This Kids Count factbook presents statistical data and examines trends for 10 indicators of children's well-being in Georgia. The indicators are: (1) low birthweight babies; (2) infant mortality; (3) child deaths; (4) teen deaths by accident, homicide, and suicide; (5) juvenile arrests; (6) reading and math scores on the Iowa Test of Basic Skills;…

  15. Kids Count in Delaware: Fact Book, 1997.

    Science.gov (United States)

    Dowshen, Steven, Ed.; Greback, Robert, Ed.; Nelson, Carl, Ed.; Schooley, Teresa L., Ed.; Sturgis, Janice, Ed.

    This KIDS COUNT report details statewide trends in the well-being of Delaware's children. The statistical profile is based on 10 main indicators of child well-being: (1) births to teens; (2) low birth weight babies; (3) infant mortality; (4) child deaths, age 1-14 years; (5) teen violent deaths by accident, homicide, and suicide; (6) juvenile…

  16. Interpretation of automated blood cell counts

    OpenAIRE

    Zühre Kaya

    2013-01-01

    Complete blood count (CBC) tests are rapid, inexpensiveand universally available, and often aid primary clinicianswith decision making about patients with severaldisorders. Thus the rapid availability of the results of CBCcould provide considerable advantage for both patientsand clinicians. Furthermore, physicians can also avoidunnecessary peripheral blood smear examination usingCBC parameters. Many hematology analyzers, which enabledus simultaneously, measure several different CBCparameters,...

  17. Counting Using Hall Algebras I. Quivers

    OpenAIRE

    Fei, Jiarui

    2011-01-01

    We survey some results on counting the rational points of moduli spaces of quiver representations. We then make generalizations to Grassmannians and flags of quiver representations. These results have nice applications to the cluster algebra. Along the way, we use the full Hopf structure of the Hall algebra of a quiver.

  18. Multidimensional time-correlated single photon counting

    Science.gov (United States)

    Becker, Wolfgang; Bergmann, Axel

    2006-10-01

    Time-correlated single photon counting (TCSPC) is based on the detection of single photons of a periodic light signal, measurement of the detection time of the photons, and the build-up of the photon distribution versus the time in the signal period. TCSPC achieves a near ideal counting efficiency and transit-time-spread-limited time resolution for a given detector. The drawback of traditional TCSPC is the low count rate, long acquisition time, and the fact that the technique is one-dimensional, i.e. limited to the recording of the pulse shape of light signals. We present an advanced TCSPC technique featuring multi-dimensional photon acquisition and a count rate close to the capability of currently available detectors. The technique is able to acquire photon distributions versus wavelength, spatial coordinates, and the time on the ps scale, and to record fast changes in the fluorescence lifetime and fluorescence intensity of a sample. Biomedical applications of advanced TCSPC techniques are time-domain optical tomography, recording of transient phenomena in biological systems, spectrally resolved fluorescence lifetime imaging, FRET experiments in living cells, and the investigation of dye-protein complexes by fluorescence correlation spectroscopy. We demonstrate the potential of the technique for selected applications.

  19. Approximate counting by hashing in bounded arithmetic

    Czech Academy of Sciences Publication Activity Database

    Jeřábek, Emil

    2009-01-01

    Roč. 74, č. 3 (2009), s. 829-860. ISSN 0022-4812 R&D Projects: GA AV ČR IAA1019401 Institutional research plan: CEZ:AV0Z10190503 Keywords : bounded arithmetic * approximate counting * universal hashing Subject RIV: BA - General Mathematics Impact factor: 0.631, year: 2009

  20. Alabama Kids Count 2001 Data Book.

    Science.gov (United States)

    Curtis, Apreill; Bogie, Don

    This Kids Count data book examines statewide trends in well-being for Alabama's children. The statistical portrait is based on 17 indicators in the areas of health, education, safety, and security. The indicators are: (1) infant mortality rate; (2) low weight births; (3) child health index; (4) births to unmarried teens; (5) first grade retention;…

  1. Alabama Kids Count 2002 Data Book.

    Science.gov (United States)

    Curtis, Apreill; Bogie, Don

    This Kids Count data book examines statewide trends in well-being of Alabamas children. The statistical portrait is based on 18 indicators in the areas of child health, education, safety, and security: (1) infant mortality rate; (2) low weight births; (3) child health index; (4) births to unmarried teens; (5) first grade retention; (6) school…

  2. A multilevel analysis of intercompany claim counts

    NARCIS (Netherlands)

    K. Antonio; E.W. Frees; E.A. Valdez

    2009-01-01

    In this paper, we use multilevel models to analyze data on claim counts provided by the General Insurance Association of Singapore, an organization consisting of most of the general insurers in Singapore. Our data comes from the financial records of automobile insurance policies followed over a peri

  3. A multilevel analysis of intercompany claim counts

    NARCIS (Netherlands)

    K. Antonio; E.W. Frees; E.A. Valdez

    2010-01-01

    It is common for professional associations and regulators to combine the claims experience of several insurers into a database known as an 'intercompany' experience data set. In this paper, we analyze data on claim counts provided by the General Insurance Association of Singapore, an organization co

  4. Reduced Component Count RGB LED Driver

    NARCIS (Netherlands)

    De Pedro, I.; Ackermann, B.

    2008-01-01

    The goal of this master thesis is to develop new drive and contrololutions, for creating white light from mixing the light of different-color LEDs, aiming at a reduced component count resulting in less space required by the electronics and lower cost. It evaluates the LED driver concept proposed in

  5. The analysis of dependent count data.

    NARCIS (Netherlands)

    Engel, J.

    1987-01-01

    In the literature, methods have been presented for the analysis of count data classified by fixed and crossed factors under the assumptions that this data can be modeled by independent binomial or Poisson distributions. In general, the mean value of these distributions depends on the levels of the c

  6. Atom trap trace analysis of {sup 39}Ar

    Energy Technology Data Exchange (ETDEWEB)

    Welte, Joachim

    2011-12-14

    Detection of {sup 39}Ar in natural water samples can be employed for radiometric dating on a timescale of 50 to 1000 years before present. This experimental work comprises the setup of an atomic beam and trap apparatus that captures and detects {sup 39}Ar atoms by the laser-cooling technique ''Atom Trap Trace Analysis''. With this approach, the limitations of low-level counting, regarding sample size and measurement time, could be overcome. In the course of this work, the hyperfine structure spectrum of the cooling transition 1s{sub 5}-2p{sub 9} has been experimentally determined. A high intensity, optically collimated beam of slow metastable argon atoms has been set up and fluorescence detection of individual {sup 39}Ar atoms in a magneto-optical trap is realized. {sup 39}Ar count rates of 1 atom in about 4 hours have been achieved for atmospheric argon. Recent improvements further suggest that even higher count rates of 1 atom/hour are within reach.

  7. Quantum abacus for counting and factorizing numbers

    International Nuclear Information System (INIS)

    We generalize the binary quantum counting algorithm of Lesovik, Suslov, and Blatter [Phys. Rev. A 82, 012316 (2010)] to higher counting bases. The algorithm makes use of qubits, qutrits, and qudits to count numbers in a base-2, base-3, or base-d representation. In operating the algorithm, the number nK is read into a K-qudit register through its interaction with a stream of n particles passing in a nearby wire; this step corresponds to a quantum Fourier transformation from the Hilbert space of particles to the Hilbert space of qudit states. An inverse quantum Fourier transformation provides the number n in the base-d representation; the inverse transformation is fully quantum at the level of individual qudits, while a simpler semiclassical version can be used on the level of qudit registers. Combining registers of qubits, qutrits, and qudits, where d is a prime number, with a simpler single-shot measurement allows us to find the powers of 2, 3, and other primes d in the number n. We show that the counting task naturally leads to the shift operation and an algorithm based on the quantum Fourier transformation. We discuss possible implementations of the algorithm using quantum spin-d systems, d-well systems, and their emulation with spin-1/2 or double-well systems. We establish the analogy between our counting algorithm and the phase estimation algorithm and make use of the latter's performance analysis in stabilizing our scheme. Applications embrace a quantum metrological scheme to measure voltage (an analog to digital converter) and a simple procedure to entangle multiparticle states.

  8. Bivariate Count Data Regression Using Series Expansions: With Applications

    OpenAIRE

    A. Colin Cameron; Per Johansson

    2004-01-01

    Most research on count data regression models, i.e. models for there the dependent variable takes only non-negative integer values or count values, has focused on the univariate case. Very little attention has been given to joint modeling of two or more counts. We propose parametric regression models for bivariate counts based on squared polynomial expansions around a baseline density. The models are more flexible than the current leading bivariate count model, the bivariate Poisson. The mode...

  9. "Bohr's Atomic Model."

    Science.gov (United States)

    Willden, Jeff

    2001-01-01

    "Bohr's Atomic Model" is a small interactive multimedia program that introduces the viewer to a simplified model of the atom. This interactive simulation lets students build an atom using an atomic construction set. The underlying design methodology for "Bohr's Atomic Model" is model-centered instruction, which means the central model of the…

  10. CONNECTIVITY INDEX OF ENVIRONMENT VALENCE AND QSPR RESEARCH FOR BOILING POINTS OF SATURATED HYDROCARBON%环价连接性指数与饱和烃沸点的QSPR研究

    Institute of Scientific and Technical Information of China (English)

    沐来龙; 冯长君

    2004-01-01

    In this paper, according to the peak numbers of the nuclear magnetic resonance and the Randic embranchment degree (δi) of carbon atom i, the carbon atom's environment valence gi is defined as. gi =(ti+δi)/2. The gi reflect the characteristic of each carbon atom, and as well as the conjunction detail of the carbon atom with other carbon atoms. So, the gi could distinguish better the chemical environment of each carbon atom in the molecule than δi. A connectivity index of environment valence (mS) and its athwart index (mS') are proposed based on the adjacency matrix and the carbon atom's environment valence gi. Among them, the 0S and 0S' include the characteristic and the connectivity of each carbon atom, the 1S and 1S' reflect the second conjunction between carbon atoms. Based on 0S' and N (the number of carbon atom), a new structural parameter symmetry degree (N∝), is defined as. N∝ =[ (0S's0Sc') N]2/3, and the N∝ reflect the size of the molecule as well as the symmetry of the molecule.The N∝, 0S and Rn (the biggest ring's edge numbers of cycloalkanes) of 474 saturated hydrocarbons (216 paraffins and 258 cycloalkanes) were calculated and correlated with their boiling points. The best regression equation was obtained as follow: In ( 1056 - Tb ) = 6. 9480 - 0. 1040N∝ - 0. 0086890S -0. 009614Rn+0. 01998Rm0.5, n=474, R=0. 9989, F=52627, S=5.63K. The model was checked up by the Jackknife's method. It should have overall steadiness and could be used for predicting the boiling point of saturated hydrocarbons.

  11. Atomic Energy Basics, Understanding the Atom Series.

    Science.gov (United States)

    Atomic Energy Commission, Oak Ridge, TN. Div. of Technical Information.

    This booklet is part of the "Understanding the Atom Series," though it is a later edition and not included in the original set of 51 booklets. A basic survey of the principles of nuclear energy and most important applications are provided. These major topics are examined: matter has molecules and atoms, the atom has electrons, the nucleus,…

  12. How fast can quantum annealers count?

    International Nuclear Information System (INIS)

    We outline an algorithm for the quantum counting problem using adiabatic quantum computation (AQC). We show that the mechanism of quantum-adiabatic evolution may be utilized toward estimating the number of solutions to a problem, and not only to find them. Using local adiabatic evolution, a process in which the adiabatic procedure is performed at a variable rate, the problem of counting the number of marked items in an unstructured database is solved quadratically faster than the corresponding classical algorithm. The above algorithm provides further evidence for the potentially powerful capabilities of AQC as a paradigm for more efficient problem solving on a quantum computer, and may be used as the basis for solving more sophisticated problems. (paper)

  13. MOIRCS Deep Survey. I: DRG Number Counts

    CERN Document Server

    Kajisawa, M; Suzuki, R; Tokoku, C; Uchimoto, Y K; Yoshikawa, T; Akiyama, M; Ichikawa, T; Ouchi, M; Omata, K; Tanaka, I; Nishimura, T; Yamada, T; Kajisawa, Masaru; Konishi, Masahiro; Suzuki, Ryuji; Tokoku, Chihiro; Uchimoto, Yuka Katsuno; Yoshikawa, Tomohiro; Akiyama, Masayuki; Ichikawa, Takashi; Ouchi, Masami; Omata, Koji; Tanaka, Ichi; Nishimura, Tetsuo; Yamada, Toru

    2006-01-01

    We use very deep near-infrared imaging data taken with Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru Telescope to investigate the number counts of Distant Red Galaxies (DRGs). We have observed a 4x7 arcmin^2 field in the Great Observatories Origins Deep Survey North (GOODS-N), and our data reach J=24.6 and K=23.2 (5sigma, Vega magnitude). The surface density of DRGs selected by J-K>2.3 is 2.35+-0.31 arcmin^-2 at K22 is smaller than that expected from the number counts at the brighter magnitude. The result indicates that while there are many bright galaxies at 222 suggest that the mass-dependent color distribution, where most of low-mass galaxies are blue while more massive galaxies tend to have redder colors, had already been established at that epoch.

  14. MOIRCS Deep Survey. I: DRG Number Counts

    Science.gov (United States)

    Kajisawa, Masaru; Konishi, Masahiro; Suzuki, Ryuji; Tokoku, Chihiro; Uchimoto, Yuka; Katsuno; Yoshikawa, Tomohiro; Akiyama, Masayuki; Ichikawa, Takashi; Ouchi, Masami; Omata, Koji; Tanaka, Ichi; Nishimura, Tetsuo; Yamada, Toru

    2006-12-01

    We used very deep near-infrared imaging data taken with the Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru Telescope to investigate the number counts of Distant Red Galaxies (DRGs). We observed a 4' × 7' field in the Great Observatories Origins Deep Survey-North (GOODS-N), and our data reached J=24.6 and K=23.2 (5σ, Vega magnitude). The surface density of DRGs selected by J - K > 2.3 is 2.35 ± 0.31 arcmin-2 at K 22 is smaller than that expected from the number counts at the brighter magnitude. The result indicates that while there are many bright galaxies at 2 22 suggest that the mass-dependent color distribution, where most of the low-mass galaxies are blue, while more massive galaxies tend to have redder colors, had already been established at that epoch.

  15. Efficient Prime Counting and the Chebyshev Primes

    Directory of Open Access Journals (Sweden)

    Michel Planat

    2013-01-01

    Full Text Available The function where is the logarithm integral and the number of primes up to is well known to be positive up to the (very large Skewes' number. Likewise, according to Robin's work, the functions and , where and are Chebyshev summatory functions, are positive if and only if Riemann hypothesis (RH holds. One introduces the jump function at primes and one investigates , , and . In particular, , and for . Besides, for any odd , an infinite set of the so-called Chebyshev primes. In the context of RH, we introduce the so-called Riemann primes as champions of the function (or of the function . Finally, we find a good prime counting function , that is found to be much better than the standard Riemann prime counting function.

  16. Pharmacy Automation-Pill Counting Design

    Directory of Open Access Journals (Sweden)

    Omer Mohamed Adam Adlan

    2015-03-01

    Full Text Available Dispensing medications in a community pharmacy was a time-consuming operation. The pharmacist dispensed most prescriptions that were in tablet or capsule form with a simple tray and spatula. Many new medications were being developed by pharmaceutical manufacturers at an ever-increasing pace, and the prices of those medications were rising steeply. A typical community pharmacist was working longer hours and often forced to hire additional staff to handle increased workloads. This extra workload did not allow the time to focus on safety issues. This new factor led to the concept of using a machine to count medications. This paper introduces a design based on using microcontrollers for counting tablets and capsules . A production flow is build to automate the whole operations

  17. Recent progress with digital coincidence counting

    International Nuclear Information System (INIS)

    Digital Coincidence Counting (DCC) is a new technique, based on the older method of analogue coincidence counting. It has been developed by ANSTO as a faster more reliable means of determining the activity of ionising radiation samples. The technique employs a dual channel analogue to digital converter acquisition system for collecting pulse information from a 4Π beta detector and a NaI(Tl) gamma detector. The digitised pulse information is stored on a high speed hard disk and timing information for both channels is also stored. The data may subsequently be recalled and analysed using software based algorithms. The system is operational and results are now being routinely collected and analysed. Some of the early work is presented for Co-60, Na-22 and Sm-153

  18. BMI in relation to sperm count

    DEFF Research Database (Denmark)

    Sermondade, N; Faure, C; Fezeu, L;

    2013-01-01

    BACKGROUND The global obesity epidemic has paralleled a decrease in semen quality. Yet, the association between obesity and sperm parameters remains controversial. The purpose of this report was to update the evidence on the association between BMI and sperm count through a systematic review with...... meta-analysis. METHODS A systematic review of available literature (with no language restriction) was performed to investigate the impact of BMI on sperm count. Relevant studies published until June 2012 were identified from a Pubmed and EMBASE search. We also included unpublished data (n = 717 men......) obtained from the Infertility Center of Bondy, France. Abstracts of relevant articles were examined and studies that could be included in this review were retrieved. Authors of relevant studies for the meta-analysis were contacted by email and asked to provide standardized data. RESULTS A total of 21...

  19. Photon Counting OTDR : Advantages and Limitations

    CERN Document Server

    Eraerds, Patrick; Zhang, Jun; Zbinden, Hugo; Gisin, Nicolas

    2010-01-01

    We give detailed insight into photon counting OTDR (nu-OTDR) operation, ranging from Geiger mode operation of avalanche photodiodes (APD), analysis of different APD bias schemes, to the discussion of OTDR perspectives. Our results demonstrate that an InGaAs/InP APD based nu-OTDR has the potential of outperforming the dynamic range of a conventional state-of-the-art OTDR by 10 dB as well as the 2-point resolution by a factor of 20. Considering the trace acquisition speed of nu-OTDRs, we find that a combination of rapid gating for high photon flux and free running mode for low photon flux is the most efficient solution. Concerning dead zones, our results are less promising. Without additional measures, e.g. an optical shutter, the photon counting approach is not competitive.

  20. Teach us atom structure

    International Nuclear Information System (INIS)

    This book is written to teach atom structure in very easy way. It is divided into nine chapters, which indicates what is the components of matter? when we divide matter continuously, it becomes atom, what did atom look like? particles comprised of matter is not only atom, discover of particles comprised of atom, symbol of element, various radiation, form alchemy to nuclear transmutation, shape of atom is evolving. It also has various pictures in each chapters to explain easily.

  1. Teach us atom structure

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Suh Yeon

    2006-08-15

    This book is written to teach atom structure in very easy way. It is divided into nine chapters, which indicates what is the components of matter? when we divide matter continuously, it becomes atom, what did atom look like? particles comprised of matter is not only atom, discover of particles comprised of atom, symbol of element, various radiation, form alchemy to nuclear transmutation, shape of atom is evolving. It also has various pictures in each chapters to explain easily.

  2. Exact and approximate Bayesian estimation of net counting rates

    International Nuclear Information System (INIS)

    The stochastic fluctuations in the number of disintegrations, which had already been studied experimentally by Rutherford and other investigators at the beginning of the twentieth century, make estimation of net counting rates in the presence of background counts a challenging statistical problem. Exact and approximate Bayesian estimates of net count rates using Poisson and normal distributions for the number of counts detected during varying counting intervals are derived. The posterior densities for the net count rate are derived and plotted for uniform priors. The graphs for the exact, Poisson based, and for the approximate posterior densities of the background and net count rates, resulting from the normal approximation to the Poisson distribution, were compared. No practical differences were found when the number of observed gross counts is large. Small numerical differences in the posterior expectations and standard deviation of the counting rates appeared when the number of observed counts was small. A table showing some of these numerical differences for different background and gross counts is included. A normal approximation to the Poisson is satisfactory for the analysis of counting data when the number of observed counts is large. Some caution has to be exercised when the number of observed counts is small. (author)

  3. Counting and Arithmetic of the Inca

    OpenAIRE

    Ximena Catepillán; Waclaw Szymanski

    2012-01-01

    The Inca Empire - the greatest pre-Columbian empire on the American continent - extended from Ecuador to central Chile for more than five thousand miles. Its capital was Cuzco established in the high Peruvian Andes. This highly advanced civilization developed a counting system used to run the empire - in particular, to build the 14,000 mile road structure and monumental architecture. Some of the algorithms believed to be used by the Inca to do computations using a yupana, an ancient calculati...

  4. Synchronous counting and computational algorithm design

    OpenAIRE

    Dolev, Danny; Korhonen, Janne H.; Lenzen, Christoph; Rybicki, Joel; Suomela, Jukka

    2013-01-01

    Consider a complete communication network on $n$ nodes, each of which is a state machine. In synchronous 2-counting, the nodes receive a common clock pulse and they have to agree on which pulses are "odd" and which are "even". We require that the solution is self-stabilising (reaching the correct operation from any initial state) and it tolerates $f$ Byzantine failures (nodes that send arbitrary misinformation). Prior algorithms are expensive to implement in hardware: they require a source of...

  5. What counts as evidence of inclusive education?

    OpenAIRE

    Florian, Lani

    2014-01-01

    Inclusive education takes many forms, raising important questions about what constitutes good practice, what counts as evidence of such practice and how it can be known. This paper responds to Göransson and Nilholm’s critical review of research on inclusive education by considering why a clear working definition of inclusion has thus far proved elusive. It agrees that new types of studies and more theoretically informed work is needed if knowledge about inclusive education is to advance. A fr...

  6. Inventory verification measurements using neutron multiplicity counting

    Energy Technology Data Exchange (ETDEWEB)

    Ensslin, N.; Foster, L.A.; Harker, W.C.; Krick, M.S.; Langner, D.G.

    1998-12-31

    This paper describes a series of neutron multiplicity measurements of large plutonium samples at the Los Alamos Plutonium Facility. The measurements were corrected for bias caused by neutron energy spectrum shifts and nonuniform multiplication, and are compared with calorimetry/isotopics. The results show that multiplicity counting can increase measurement throughput and yield good verification results for some inventory categories. The authors provide recommendations on the future application of the technique to inventory verification.

  7. Step Counting Using Smartphone-Based Accelerometer

    Directory of Open Access Journals (Sweden)

    Ms. Najme Zehra Naqvi

    2012-05-01

    Full Text Available This paper presents a method for counting the number of steps taken by a user, while walking at any variable speed, using smartphone-based accelerometer. For this purpose, the steps are detected based on a relation between frequency of step, which varies inversely with speed of motion, and the magnitude of accelerometer signal. The pattern of the forward acceleration was observed to arrive at the final relation.

  8. Counting Lattice Animals in High Dimensions

    OpenAIRE

    Luther, Sebastian; Mertens, Stephan

    2011-01-01

    We present an implementation of Redelemeier's algorithm for the enumeration of lattice animals in high dimensional lattices. The implementation is lean and fast enough to allow us to extend the existing tables of animal counts, perimeter polynomials and series expansion coefficients in $d$-dimensional hypercubic lattices for $3 \\leq d\\leq 10$. From the data we compute formulas for perimeter polynomials for lattice animals of size $n\\leq 11$ in arbitrary dimension $d$. When amended by combinat...

  9. Frontal subregions mediating Elevator Counting task performance

    OpenAIRE

    MacPherson, S. E.; Turner, M. S.; Bozzali, M; Cipolotti, L.; Shallice, T.

    2010-01-01

    Deficits in sustained attention may lead to action slips in everyday life as irrelevant action sequences are inappropriately triggered internally or by the environment While deficits in sustained attention have been associated with damage to the frontal lobes of the brain little is known about the role of the frontal lobes in the Elevator Counting subtest of the Test of Everyday Attention In the current study 55 frontal patients subdivided into medial orbital and lateral subgroups 18 patients...

  10. Counting graphene layers with very slow electrons

    Czech Academy of Sciences Publication Activity Database

    Frank, Luděk; Mikmeková, Eliška; Müllerová, Ilona; Lejeune, M.

    2015-01-01

    Roč. 106, 09 JAN (2015), 013117:1-5. ISSN 0003-6951 R&D Projects: GA TA ČR(CZ) TE01020118; GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : graphene * ultralow energy STEM * counting graphene layers * clean ing of graphene * 2D crystals Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.302, year: 2014

  11. Soudan Low Background Counting Facility (SOLO)

    International Nuclear Information System (INIS)

    The Soudan Low Background Counting Facility (SOLO) has been in operation at the Soudan Mine, MN since March 2003. In the past two years, we have gamma-screened samples for the Majorana, CDMS and XENON experiments. With individual sample exposure times of up to two weeks we have measured sample contamination down to the 0.1 ppb level for 238U / 232Th, and down to the 0.25 ppm level for 40K

  12. Phonon counting and intensity interferometry of a nanomechanical resonator.

    Science.gov (United States)

    Cohen, Justin D; Meenehan, Seán M; MacCabe, Gregory S; Gröblacher, Simon; Safavi-Naeini, Amir H; Marsili, Francesco; Shaw, Matthew D; Painter, Oskar

    2015-04-23

    In optics, the ability to measure individual quanta of light (photons) enables a great many applications, ranging from dynamic imaging within living organisms to secure quantum communication. Pioneering photon counting experiments, such as the intensity interferometry performed by Hanbury Brown and Twiss to measure the angular width of visible stars, have played a critical role in our understanding of the full quantum nature of light. As with matter at the atomic scale, the laws of quantum mechanics also govern the properties of macroscopic mechanical objects, providing fundamental quantum limits to the sensitivity of mechanical sensors and transducers. Current research in cavity optomechanics seeks to use light to explore the quantum properties of mechanical systems ranging in size from kilogram-mass mirrors to nanoscale membranes, as well as to develop technologies for precision sensing and quantum information processing. Here we use an optical probe and single-photon detection to study the acoustic emission and absorption processes in a silicon nanomechanical resonator, and perform a measurement similar to that used by Hanbury Brown and Twiss to measure correlations in the emitted phonons as the resonator undergoes a parametric instability formally equivalent to that of a laser. Owing to the cavity-enhanced coupling of light with mechanical motion, this effective phonon counting technique has a noise equivalent phonon sensitivity of 0.89 ± 0.05. With straightforward improvements to this method, a variety of quantum state engineering tasks using mesoscopic mechanical resonators would be enabled, including the generation and heralding of single-phonon Fock states and the quantum entanglement of remote mechanical elements. PMID:25903632

  13. Phonon counting and intensity interferometry of a nanomechanical resonator

    Science.gov (United States)

    Cohen, Justin D.; Meenehan, Seán M.; Maccabe, Gregory S.; Gröblacher, Simon; Safavi-Naeini, Amir H.; Marsili, Francesco; Shaw, Matthew D.; Painter, Oskar

    2015-04-01

    In optics, the ability to measure individual quanta of light (photons) enables a great many applications, ranging from dynamic imaging within living organisms to secure quantum communication. Pioneering photon counting experiments, such as the intensity interferometry performed by Hanbury Brown and Twiss to measure the angular width of visible stars, have played a critical role in our understanding of the full quantum nature of light. As with matter at the atomic scale, the laws of quantum mechanics also govern the properties of macroscopic mechanical objects, providing fundamental quantum limits to the sensitivity of mechanical sensors and transducers. Current research in cavity optomechanics seeks to use light to explore the quantum properties of mechanical systems ranging in size from kilogram-mass mirrors to nanoscale membranes, as well as to develop technologies for precision sensing and quantum information processing. Here we use an optical probe and single-photon detection to study the acoustic emission and absorption processes in a silicon nanomechanical resonator, and perform a measurement similar to that used by Hanbury Brown and Twiss to measure correlations in the emitted phonons as the resonator undergoes a parametric instability formally equivalent to that of a laser. Owing to the cavity-enhanced coupling of light with mechanical motion, this effective phonon counting technique has a noise equivalent phonon sensitivity of 0.89 +/- 0.05. With straightforward improvements to this method, a variety of quantum state engineering tasks using mesoscopic mechanical resonators would be enabled, including the generation and heralding of single-phonon Fock states and the quantum entanglement of remote mechanical elements.

  14. Enabling photon counting detectors with dynamic attenuators

    Science.gov (United States)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-03-01

    Photon-counting x-ray detectors (PCXDs) are being investigated as a replacement for conventional x-ray detectors because they promise several advantages, including better dose efficiency, higher resolution and spectral imaging. However, many of these advantages disappear when the x-ray flux incident on the detector is too high. We recently proposed a dynamic, piecewise-linear attenuator (or beam shaping filter) that can control the flux incident on the detector. This can restrict the operating range of the PCXD to keep the incident count rate below a given limit. We simulated a system with the piecewise-linear attenuator and a PCXD using raw data generated from forward projected DICOM files. We investigated the classic paralyzable and nonparalyzable PCXD as well as a weighted average of the two, with the weights chosen to mimic an existing PCXD (Taguchi et al, Med Phys 2011). The dynamic attenuator has small synergistic benefits with the nonparalyzable detector and large synergistic benefits with the paralyzable detector. Real PCXDs operate somewhere between these models, and the weighted average model still shows large benefits from the dynamic attenuator. We conclude that dynamic attenuators can reduce the count rate performance necessary for adopting PCXDs.

  15. Statistical treatment of nuclear counting results

    Directory of Open Access Journals (Sweden)

    Dolićanin Ćemal B.

    2011-01-01

    Full Text Available Since the exact time a specific nucleus undergoes radioactive decay cannot be specified, nor can showers caused by secondary cosmic rays be predicted, statistical laws play an important role in almost all cases of experimental nuclear physics. This paper describes the method for the statistical treatment of nuclear counting results obtained experimentally by taking into account random variables pertaining to both frequent and infrequent phenomena. When processing counting measurement data, it is recommended to first discard spurious random variables that spoil the statistics by using Chauvenet’s criterion, as well as to test if the results in the statistical sample follow a unique statistical distribution by using the Wilcoxon rank-sum test (U-test. The verification of the suggested statistical method was performed on counting statistics obtained both from the radioactive source Cs-137 and background radiation, expected to follow the normal distribution and the Poisson distribution, respectively. Results show that the application of the proposed statistical method excludes random fluctuations of the radioactive source or of the background radiation from the total statistical sample, as well as possible inadequacies in the experimental set-up and show an extremely effective agreement of the theoretical distribution of random variables with the corresponding experimentally obtained random variables.

  16. Savannah River National Laboratory Underground Counting Facility

    Science.gov (United States)

    Brown, Tim

    2006-10-01

    The SRNL UCF is capable of detecting extremely small amounts of radioactivity in samples, providing applications in forensics, environmental analyses, and nonproliferation. Past customers of the UCF have included NASA, (Long Duration Exposure Facility) the IAEA, (Iraq), and nonproliferation concerns. The SRNL UCF was designed to conduct ultra-low level gamma-ray analyses for radioisotopes at trace levels. Detection sensitivity is enhanced by background reduction, high detector efficiency, and long counting times. Backgrounds from cosmic-rays, construction materials, and radon are reduced by counting underground, active and passive shielding, (pre-WWII steel) and situation behind a Class 10,000 clean facility. High-detection efficiency is provided by a well detector for small samples and three large HPGe detectors. Sample concentration methods such as ashing or chemical separation are also used. Count times are measured in days. Recently, two SCUREF programs were completed with the University of South Carolina to further enhance UCF detection sensitivity. The first developed an ultra-low background HPGe detector and the second developed an anti-cosmic shield that further reduces the detector background. In this session, we will provide an overview status of the recent improvements made in the UCF and future directions for increasing sensitivity.

  17. Galactic structure studies with BATC star counts

    CERN Document Server

    Du, C; Ma, J; Chen, A B C; Yang, Y; Li, J; Wu, H; Jiang, Z; Chen, J; Du, Cuihua; Zhou, Xu; Ma, Jun; Chen, Alfred B-C; Yang, Yanbin; Li, Jiuli; Wu, Hong; Jiang, Zhaoji; Chen, Jiansheng

    2003-01-01

    We report the first results of star counts carried out with the National Astronomical Observatories (NAOC) 60/90 cm Schmidt Telescope in 15 intermediate-band filters from 3000 to 10000 {\\AA} in the BATC survey. We analyze a sample of over 1400 main sequence stars ($14\\le$V$\\le21$), which lie in the field with central coordinates R.A.=$09^h53^m13^s.30$ and DEC=47$^\\circ49^{\\prime}00^{\\prime\\prime}.0$ (J2000). The field of view is 0.95 deg$^{2}$, and the spatial scale was $1\\arcsec.67$. In our model, the distribution of stars perpendicular to the plane of the Galaxy is given by two exponential disks (thin disk plus thick disk) and a de Vaucouleurs halo. Based on star counts, we derive the scale heights of the thin disk to be $320^{+14}_{-15}$ pc and of the thick disk to be $640^{+30}_{-32}$ pc, respectively, with a local density of $7.0\\pm1%$ of the thin disk. We find that the observed counts support an axial ratio of $c/a\\le0.6$ for a de Vaucouleurs $r^{1/4}$ law, implying a more flattened halo. We also derive...

  18. Atomic phase diagram

    Institute of Scientific and Technical Information of China (English)

    LI Shichun

    2004-01-01

    Based on the Thomas-Fermi-Dirac-Cheng model, atomic phase diagram or electron density versus atomic radius diagram describing the interaction properties of atoms of different kinds in equilibrium state is developed. Atomic phase diagram is established based on the two-atoms model. Besides atomic radius, electron density and continuity condition for electron density on interfaces between atoms, the lever law of atomic phase diagram involving other physical parameters is taken into account, such as the binding energy, for the sake of simplicity.

  19. Atomizer design for viscous-melt atomization

    Energy Technology Data Exchange (ETDEWEB)

    Czisch, C. [Chemical Engineering Department, University Bremen, Badgasteiner Str. 3, 28359 Bremen (Germany); Fritsching, U. [Chemical Engineering Department, University Bremen, Badgasteiner Str. 3, 28359 Bremen (Germany)], E-mail: ufri@iwt.uni-bremen.de

    2008-03-25

    The development of a gas atomization unit is introduced, which utilizes characteristic flow effects for efficient fragmentation of viscous liquids and melts. The proposed device combines a classical rotary atomizer with an external mixing gas atomizer. Here, the liquid stream is first transformed into a thin liquid sheet before disintegration. Thereby the specific surface energy is increased without breakup. The movement of the free flowing liquid film is controlled by the local gas flow field in order to transport the film into the most effective atomization region. The fragmentation process itself is caused by a perpendicular impinging gas stream. Numerical flow simulations are used for the development of the hybrid atomizer construction. Experiments using viscous model liquids show that for constant air-to-liquid mass-flow ratio the particle size is reduced using the hybrid atomizer compared with a conventional gas atomizer. Results of model experiments as well as of experiments with a viscous mineral melt are discussed.

  20. Atomizer design for viscous-melt atomization

    International Nuclear Information System (INIS)

    The development of a gas atomization unit is introduced, which utilizes characteristic flow effects for efficient fragmentation of viscous liquids and melts. The proposed device combines a classical rotary atomizer with an external mixing gas atomizer. Here, the liquid stream is first transformed into a thin liquid sheet before disintegration. Thereby the specific surface energy is increased without breakup. The movement of the free flowing liquid film is controlled by the local gas flow field in order to transport the film into the most effective atomization region. The fragmentation process itself is caused by a perpendicular impinging gas stream. Numerical flow simulations are used for the development of the hybrid atomizer construction. Experiments using viscous model liquids show that for constant air-to-liquid mass-flow ratio the particle size is reduced using the hybrid atomizer compared with a conventional gas atomizer. Results of model experiments as well as of experiments with a viscous mineral melt are discussed

  1. Cold Matter Assembled Atom-by-Atom

    CERN Document Server

    Endres, Manuel; Keesling, Alexander; Levine, Harry; Anschuetz, Eric R; Krajenbrink, Alexandre; Senko, Crystal; Vuletic, Vladan; Greiner, Markus; Lukin, Mikhail D

    2016-01-01

    The realization of large-scale fully controllable quantum systems is an exciting frontier in modern physical science. We use atom-by-atom assembly to implement a novel platform for the deterministic preparation of regular arrays of individually controlled cold atoms. In our approach, a measurement and feedback procedure eliminates the entropy associated with probabilistic trap occupation and results in defect-free arrays of over 50 atoms in less than 400 ms. The technique is based on fast, real-time control of 100 optical tweezers, which we use to arrange atoms in desired geometric patterns and to maintain these configurations by replacing lost atoms with surplus atoms from a reservoir. This bottom-up approach enables controlled engineering of scalable many-body systems for quantum information processing, quantum simulations, and precision measurements.

  2. A mind you can count on: validating breath counting as a behavioral measure of mindfulness

    Directory of Open Access Journals (Sweden)

    Daniel B Levinson

    2014-10-01

    Full Text Available Mindfulness practice of present moment awareness promises many benefits, but has eluded rigorous behavioral measurement. To date, research has relied on self-reported mindfulness or heterogeneous mindfulness trainings to infer skillful mindfulness practice and its effects. In four independent studies with over 400 total participants, we present the first construct validation of a behavioral measure of mindfulness, breath counting. We found it was reliable, correlated with self-reported mindfulness, differentiated long-term meditators from age-matched controls, and was distinct from sustained attention and working memory measures. In addition, we employed breath counting to test the nomological network of mindfulness. As theorized, we found skill in breath counting associated with more meta-awareness, less mind wandering, better mood, and greater nonattachment (i.e. less attentional capture by distractors formerly paired with reward. We also found in a randomized online training study that 4 weeks of breath counting training improved mindfulness and decreased mind wandering relative to working memory training and no training controls. Together, these findings provide the first evidence for breath counting as a behavioral measure of mindfulness.

  3. CalCOFI Larvae Counts, Scientific Names TF to U

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish larvae counts and standardized counts for larvae captured in CalCOFI icthyoplankton nets (primarily vertical [Calvet or Pairovet], oblique [bongo or ring...

  4. Dahomey NWR - Avian Point Counts Reforestation Areas in 2009

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Report contains summary of avain point counts done in reforested areas on Dahomey NWR in 2009 including the actual point count data sheets. Data may have been put...

  5. Testing Crater Counting Assumptions with the Cratered Terrain Evolution Model

    Science.gov (United States)

    Minton, D. A.; Richardson, J. E.; Fassett, C. I.

    2015-05-01

    Using CTEM to answer the questions; 1) How close to Poisson-distributed are crater count uncertainties? and 2) How does observed clustering in crater count densities of large craters relate to the changes in the impactor flux?

  6. Avian Point Count Locations - Dahomey NWR 2007-2008

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Map depicts locations of avian point counts conducted on Dahomey in 2007 and 2008. Actual point count data are contained in the avian knowledge network database

  7. Alaska Steller sea lion Count Database (Non-pups)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This database contains counts of adult and juvenile (non-pup) Steller sea lions on rookeries and haulouts in Alaska made between 1904 and 2015. Non-pup counts have...

  8. CalCOFI Larvae Counts, Scientific Names SB to SC

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish larvae counts and standardized counts for larvae captured in CalCOFI icthyoplankton nets (primarily vertical [Calvet or Pairovet], oblique [bongo or ring...

  9. CalCOFI Larvae Counts, Scientific Names CI to CO

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Fish larvae counts and standardized counts for larvae captured in CalCOFI icthyoplankton nets (primarily vertical [Calvet or Pairovet], oblique [bongo or ring...

  10. Quantitative clinical uptake measurements using conjugate counting

    International Nuclear Information System (INIS)

    While the use of conjugate counting for determination of organ uptake in human subjects has been extensively described, in the present study the determination of the organ uptake of ortho-iodohippurate presented several opportunities for validation of the in vivo counting data. Ortho-iodohippurate is distributed in the extracellular space, is largely extracted on each pass through the kidneys, and is not significantly deiodinated in vivo. Thus, the kidney uptake rate should be proportional to the blood level, the appearance rate of activity in the bladder is equal to the disappearance rate from the kidneys, and direct measurement of activity in the urine after voiding provides an internal standard for imaging measurements of bladder activity. Since the activity levels in the kidneys, bladder, and remainder of the body changed fairly rapidly, especially in the first 20 to 30 minutes following injection, posterior images of the trunk including kidneys and bladder were obtained continuously using a gamma camera fitted with a diverging collimator for 30 minutes and then at intervals for several hours. Simultaneous conjugate counting determinations were made using a whole body scanning system previously described at these meetings. Imaging data corrected for decay and adjacent background were fitted by least squares methods to curves representing a sum of exponentials, and the curves were normalized to the conjugate uptake measurements. The uptake curves of the kidneys and bladder matched well with the direct measurements of the urinary excretion. Data were collected in 16 normal subjects, and the estimated absorbed dose was calculated for the kidneys, the bladder and the remainder of the body for seven radioisotopes of iodine. 4 references, 6 figures, 2 tables

  11. An exact exponential time algorithm for counting bipartite cliques

    DEFF Research Database (Denmark)

    Kutzkov, Konstantin

    2012-01-01

    We present a simple exact algorithm for counting bicliques of given size in a bipartite graph on n vertices. We achieve running time of O(1.249^n), improving upon known exact algorithms for finding and counting bipartite cliques.......We present a simple exact algorithm for counting bicliques of given size in a bipartite graph on n vertices. We achieve running time of O(1.249^n), improving upon known exact algorithms for finding and counting bipartite cliques....

  12. Modeling female fertility using inflated count data models

    OpenAIRE

    Maria Melkersson; Dan-Olof Rooth

    2000-01-01

    For modeling complete female fertility we propose a zero-and-two-inflated count data model, which accounts for a relative excess of both zero and two children. As the underlying distribution of counts we use the standard Poisson distribution and the more general Gamma count distribution. We compare our proposed model with standard count data models by using data on complete fertilities for a sample of Swedish women. The preferred specification for Swedish fertility data is the zero-and-two in...

  13. Stable atomic hydrogen: Polarized atomic beam source

    International Nuclear Information System (INIS)

    We have carried out experiments with stable atomic hydrogen with a view to possible applications in polarized targets or polarized atomic beam sources. Recent results from the stabilization apparatus are described. The first stable atomic hydrogen beam source based on the microwave extraction method (which is being tested ) is presented. The effect of the stabilized hydrogen gas density on the properties of the source is discussed. (orig.)

  14. Full Counting Statistics of Stationary Particle Beams

    CERN Document Server

    Kiukas, J; Werner, R F

    2010-01-01

    We present a general scheme for treating particle beams, including stationary beams, as many particle systems. This includes the full counting statistics and the requirements of Bose/Fermi symmetry. We treat in detail a model of a source, creating particles in a fixed state, which then evolve under the free time evolution, and we determine the resulting stationary beam in the far field. In comparison to the one-particle picture we obtain a correction from Bose/Fermi statistics, which depends on the emission rate.

  15. A new sieve for distinct coordinate counting

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We present a new sieve for the distinct coordinate counting problem.This significantly improves the classical inclusion-exclusion sieve for this problem,in the sense that the number of terms is reduced from 2(k 2) to k!,and reduced further to p(k) in the symmetric case,where p(k) denotes the number of partitions of k.As an illustration of applications,we give an in-depth study of a basic example arising from coding theory and graph theory.

  16. Applications of low level liquid scintillation counting

    International Nuclear Information System (INIS)

    Low level liquid scintillation counting is reviewed in terms of its present use and capabilities for measuring low activity samples. New areas of application of the method are discussed with special interest directed to the food industry and environmental monitoring. Advantages offered in the use of a low background liquid scintillation counter for the nuclear power industry and nuclear navy are discussed. Attention is drawn to the need for commercial development of such instrumentation to enable wider use of the method. A user clientele is suggested as is the required technology to create such a counter

  17. Counting lattice animals in high dimensions

    Science.gov (United States)

    Luther, Sebastian; Mertens, Stephan

    2011-09-01

    We present an implementation of Redelemeier's algorithm for the enumeration of lattice animals in high-dimensional lattices. The implementation is lean and fast enough to allow us to extend the existing tables of animal counts, perimeter polynomials and series expansion coefficients in d-dimensional hypercubic lattices for 3 lattice animals of size n lattice animals of size n <= 14 and arbitrary d. We also use the enumeration data to compute numerical estimates for growth rates and exponents in high dimensions that agree very well with Monte Carlo simulations and recent predictions from field theory.

  18. Active neutron multiplicity counting of bulk uranium

    International Nuclear Information System (INIS)

    This paper describes a new nondestructive assay technique being developed to assay bulk uranium containing kilogram quantities of 235U. The new technique uses neutron multiplicity analysis of data collected with a coincidence counter outfitted with AmLi neutron sources. We have calculated the expected neutron multiplicity count rate and assay precision for this technique and will report on its expected performance as a function of detector design characteristics, 235U sample mass, AmLi source strength, and source-to-sample coupling. 11 refs., 2 figs., 2 tabs

  19. Strange Curves, Counting Rabbits, & Other Mathematical Explorations

    CERN Document Server

    Ball, Keith

    2011-01-01

    How does mathematics enable us to send pictures from space back to Earth? Where does the bell-shaped curve come from? Why do you need only 23 people in a room for a 50/50 chance of two of them sharing the same birthday? In Strange Curves, Counting Rabbits, and Other Mathematical Explorations, Keith Ball highlights how ideas, mostly from pure math, can answer these questions and many more. Drawing on areas of mathematics from probability theory, number theory, and geometry, he explores a wide range of concepts, some more light-hearted, others central to the development of the field and used dai

  20. Optimal Planar Orthogonal Skyline Counting Queries

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Larsen, Kasper Green

    2014-01-01

    counting queries, i.e. given a query rectangle R to report the size of the skyline of P\\cap R. We present a data structure for storing n points with integer coordinates having query time O(lg n/lglg n) and space usage O(n). The model of computation is a unit cost RAM with logarithmic word size. We prove...... that these bounds are the best possible by presenting a lower bound in the cell probe model with logarithmic word size: Space usage nlgO(1) n implies worst case query time Ω(lg n/lglg n)....

  1. Applied categorical and count data analysis

    CERN Document Server

    Tang, Wan; Tu, Xin M

    2012-01-01

    Introduction Discrete Outcomes Data Source Outline of the BookReview of Key Statistical ResultsSoftwareContingency Tables Inference for One-Way Frequency TableInference for 2 x 2 TableInference for 2 x r TablesInference for s x r TableMeasures of AssociationSets of Contingency Tables Confounding Effects Sets of 2 x 2 TablesSets of s x r TablesRegression Models for Categorical Response Logistic Regression for Binary ResponseInference about Model ParametersGoodness of FitGeneralized Linear ModelsRegression Models for Polytomous ResponseRegression Models for Count Response Poisson Regression Mode

  2. An approximation algorithm for counting contingency tables

    OpenAIRE

    Barvinok, Alexander; Luria, Zur; Samorodnitsky, Alex; Yong, Alexander

    2008-01-01

    We present a randomized approximation algorithm for counting contingency tables, mxn non-negative integer matrices with given row sums R=(r_1, ..., r_m) and column sums C=(c_1, ..., c_n). We define smooth margins (R,C) in terms of the typical table and prove that for such margins the algorithm has quasi-polynomial N^{O(ln N)} complexity, where N=r_1+...+r_m=c_1+...+c_n. Various classes of margins are smooth, e.g., when m=O(n), n=O(m) and the ratios between the largest and the smallest row sum...

  3. Optimal Planar Orthogonal Skyline Counting Queries

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Larsen, Kasper Green

    counting queries, i.e. given a query rectangle R to report the size of the skyline of P\\cap R. We present a data structure for storing n points with integer coordinates having query time O(lg n/lglg n) and space usage O(n). The model of computation is a unit cost RAM with logarithmic word size. We prove...... that these bounds are the best possible by presenting a lower bound in the cell probe model with logarithmic word size: Space usage nlgO(1) n implies worst case query time Ω(lg n/lglg n)....

  4. ARITHMETIC PROGRESSIONS FOR COUNTING PRIME NUMBERS

    Directory of Open Access Journals (Sweden)

    V.J.DEVASIA

    2014-11-01

    Full Text Available In this paper two arithmetic progressions are proposed for listing and counting the prime numbers less than or equal to a given integer. From these progressions, how one can filter out prime numbers is the topic of discussion in this paper. An easy to implement formula is presented to compute the number of primes by eliminating the number of composite numbers in an iterative and recursive manner. Numerical examples are presented to demonstrate how the procedure works in an efficient and simple way.

  5. Neutral atom traps.

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  6. MULTIPHOTON IONIZATION OF ATOMS

    OpenAIRE

    Mainfray, G.

    1985-01-01

    Multiphoton ionization of one-electron atoms, such as atomic hydrogen and alkaline atoms, is well understood and correctly described by rigorous theoretical models. The present paper will be devoted to collisionless multiphoton ionization of many-electron atoms as rare gases. It induces removal of several electrons and the production of multiply charged ions. Up to Xe5+ ions are produced in Xe atoms. Doubly charged ions can be produced, either by simultaneous excitation of two electrons, or b...

  7. 20 CFR 418.3310 - Whose income do we count?

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Whose income do we count? 418.3310 Section... Subsidies Income § 418.3310 Whose income do we count? (a) We count your income. If you are married and live with your spouse in the month you file for a subsidy, or when we redetermine your eligibility for...

  8. Putting Counting to Work: Preschoolers' Understanding of Cardinal Extension

    Science.gov (United States)

    Muldoon, Kevin; Lewis, Charlie; Freeman, Norman H.

    2003-01-01

    Preschool children are often good at counting things but seem slow to learn that there is more to counting than simply finding out how many are in a single set. Counting is useful when comparing sets and when creating new sets to match existing ones. This is part of the numerical understanding that educators wish to foster in schools. In two…

  9. Low-background β count and α spectrum measuring instrument

    International Nuclear Information System (INIS)

    An low-background β count and α spectrum measuring instrument which is used to ocean radiation investigation is introduced in this paper. It capable of simultaneously measure low activity β count and analyse α spectrum. Overcome by using two sets of Instrument were measured β count and α spectrum of trouble, and reduce the measurement error. (authors)

  10. Development of New Drummed Nuclear Waste Neutron Counting System

    Institute of Scientific and Technical Information of China (English)

    ZHU; Li-qun; XU; Xiao-ming; BAI; Lei; LI; Xin-jun; GU; Shao-gang; HE; Li-xia; WANG; Mian

    2012-01-01

    <正>The development of a new neutron counting system (Fig. 1) for 200 L drummed radioactive waste measurement has been accomplished in this year. This waste neutron counting system is mainly used for solid radioactive waste classification. It is based on the passive neutron counting technique. The amount of radionuclide contained in the waste is

  11. Improving material decomposition by spectral optimization of photon counting computed tomography

    Science.gov (United States)

    Polster, C.; Hahn, K.; Gutjahr, R.; Schöck, F.; Kappler, S.; Dietrich, O.; Flohr, T. G.

    2016-03-01

    Photon counting detectors in computed tomography facilitate measurements of spectral distributions of detected X-ray quanta in discrete energy bins. Along with the dependency on wavelength and atomic number of the mass attenuation coefficient, this information allows for reconstruction of CT images of different material bases. Decomposition of two materials is considered standard in today's dual-energy techniques. With photon-counting detectors the decomposition of more than two materials becomes achievable. Efficient detection of CT-typical X-ray spectra is a hard requirement in a clinical environment. This is fulfilled by only a few sensor materials such as CdTe or CdZnTe. In contrast to energy integrating CT-detectors, the pixel dimensions must be reduced to avoid pulse pile-up problems at clinically relevant count rates. However, reducing pixel sizes leads to increased K-escape and charge sharing effects. As a consequence, the correlation between incident and detected X-ray energy is reduced. This degradation is quantified by the detector response function. The goal of this study is to improve the achievable material decomposition by adapting the incident X-ray spectrum with respect to the properties (i.e. the detector response function) of a photon counting detector. A significant improvement of a material decomposition equivalent metric is achievable when using specific materials as X-ray pre-filtration (K-edge filtering) while maintaining the applied patient dose and image quality.

  12. Full counting statistics for a quantum nanoelectromechanical system

    Science.gov (United States)

    Bennett, Steven; Clerk, Aashish

    2007-03-01

    Experiments on nanoelectromechanical systems often involve the effects of a mechanical oscillator on the current noise of a mesoscopic conductor. Coupling to the oscillator induces correlations between tunneling electrons in the conductor, leading to signatures in the shot noise. To better characterize such correlations it is useful to consider full counting statistics (FCS), which describe the complete probability distribution of tunneled charge. We study theoretically the FCS in a tunnel junction coupled to a nanomechanical oscillator. This system has been realized in experiment using an atomic point contact where one electrode is free to vibrate and it has been predicted that the oscillator dynamics leads to large signatures in the shot noise that cannot be explained classically. Thus motivated, we investigate the FCS using a reduced density matrix tracking the oscillator and the number of tunneled electrons, for which we obtain an equation of Caldeira-Leggett form with additional terms due to tunneling. N. E. Flowers-Jacobs, D. R. Schmidt, and K. W. Lehnert (submitted). A. A. Clerk and S. M. Girvin, Phys. Rev. B 70, 121303(R) (2004).

  13. IEEE standard test procedures for photomultipliers for scintillation counting and glossary for scintillation counting field

    International Nuclear Information System (INIS)

    Photomultipliers are extensively used in scintillation counting for the detection and analysis of ionizing radiation. The utilization of these detectors in a variety of technical disciplines have made standard test procedures desirable so that measurements may have the same meaning to all manufacturers and users. This standard is not intended to imply that all tests and procedures described herein are mandatory for every application, but only that such tests as are carried out on photomultipliers for scintillation and Cerenkov counting should be performed in accordance with the procedures given in this document

  14. Photon Counts Statistics in Leukocyte Cell Dynamics

    International Nuclear Information System (INIS)

    In the present experiment ultra-weak photon emission/chemiluminescence from isolated neutrophils was recorded. It is associated with the production of reactive oxygen species (ROS) in the 'respiratory burst' process which can be activated by PMA (Phorbol 12-Myristate 13-Acetate). Commonly, the reaction is demonstrated utilizing the enhancer luminol. However, with the use of highly sensitive photomultiplier equipment it is also recorded without enhancer. In that case, it can be hypothesized that photon count statistics may assist in understanding the underlying metabolic activity and cooperation of these cells. To study this hypothesis leukocytes were stimulated with PMA and increased photon signals were recorded in the quasi stable period utilizing Fano factor analysis at different window sizes. The Fano factor is defined by the variance over the mean of the number of photon within the observation time. The analysis demonstrated that the Fano factor of true signal and not of the surrogate signals obtained by random shuffling increases when the window size increased. It is concluded that photon count statistics, in particular Fano factor analysis, provides information regarding leukocyte interactions. It opens the perspective to utilize this analytical procedure in (in vivo) inflammation research. However, this needs further validation.

  15. Testing gravity with gravitational wave source counts

    Science.gov (United States)

    Calabrese, Erminia; Battaglia, Nicholas; Spergel, David N.

    2016-08-01

    We show that the gravitational wave source counts distribution can test how gravitational radiation propagates on cosmological scales. This test does not require obtaining redshifts for the sources. If the signal-to-noise ratio (ρ) from a gravitational wave source is proportional to the strain then it falls as {R}-1, thus we expect the source counts to follow {{d}}{N}/{{d}}ρ \\propto {ρ }-4. However, if gravitational waves decay as they propagate or propagate into other dimensions, then there can be deviations from this generic prediction. We consider the possibility that the strain falls as {R}-γ , where γ =1 recovers the expected predictions in a Euclidean uniformly-filled Universe, and forecast the sensitivity of future observations to deviations from standard General Relativity. We first consider the case of few objects, seven sources, with a signal-to-noise from 8 to 24, and impose a lower limit on γ, finding γ \\gt 0.33 at 95% confidence level. The distribution of our simulated sample is very consistent with the distribution of the trigger events reported by Advanced LIGO. Future measurements will improve these constraints: with 100 events, we estimate that γ can be measured with an uncertainty of 15%. We generalize the formalism to account for a range of chirp masses and the possibility that the signal falls as {exp}(-R/{R}0)/{R}γ .

  16. Testing Gravity with Gravitational Wave Source Counts

    CERN Document Server

    Calabrese, Erminia; Spergel, David N

    2016-01-01

    We show that the gravitational wave source counts distribution can test how gravitational radiation propagates on cosmological scales. This test does not require obtaining redshifts for the sources. If the signal-to-noise from a gravitational wave source is proportional to the strain then it falls as $R^{-1}$, thus we expect the source counts to follow $dN/dS \\propto S^{-4}$. However, if gravitational waves decay as they propagate or can propagate into other dimensions, then there can be deviations from this generic prediction. We consider the possibility that the signal-to-noise falls as $R^{-\\gamma}$, where $\\gamma=1$ recovers the expected predictions in a Euclidean uniformly-filled universe. We forecast the sensitivity of future observations in constraining gravitational wave physics using this method by simulating sources distributed over a finite range of signal-to-noise. We first consider the case of few objects, 7 sources, with a signal-to-noise from 8 to 24, and impose a lower limit on $\\gamma$, findi...

  17. DUSEL Ultra-Low Background Counting Facility

    Science.gov (United States)

    Thomas, Keenan

    2007-10-01

    The Homestake Mine in western South Dakota has been confirmed by the National Science Foundation (NSF) as the site for a Deep Underground Science and Engineering Laboratory (DUSEL). Many of the physics, geosciences, and microbiology experiments in the facility will be funded by DOE and NSF, and will benefit the missions of these agencies. In support of these programs, physics faculty in South Dakota and scientists at Lawrence Berkeley National Laboratory have been working together to establish a multidisciplinary research cluster to provide baseline characterization for physics and geosciences/geomicrobiology experiments at the Homestake Mine through an Ultra-Low Background Counting Facility (ULBCoF). The proposed project utilizes two low-background germanium detectors with massive shielding underground to carefully analyze materials for low background experiments. Low background experiments such as double-beta decay, solar neutrino, geoneutrino, and dark matter must control the purity of all the materials used in the construction of a detector. Measuring such low counting rates is a very challenging task that will be best accomplished by primarily using high purity germanium (HPGe) detectors.

  18. It's not the pixel count, you fool

    Science.gov (United States)

    Kriss, Michael A.

    2012-01-01

    The first thing a "marketing guy" asks the digital camera engineer is "how many pixels does it have, for we need as many mega pixels as possible since the other guys are killing us with their "umpteen" mega pixel pocket sized digital cameras. And so it goes until the pixels get smaller and smaller in order to inflate the pixel count in the never-ending pixel-wars. These small pixels just are not very good. The truth of the matter is that the most important feature of digital cameras in the last five years is the automatic motion control to stabilize the image on the sensor along with some very sophisticated image processing. All the rest has been hype and some "cool" design. What is the future for digital imaging and what will drive growth of camera sales (not counting the cell phone cameras which totally dominate the market in terms of camera sales) and more importantly after sales profits? Well sit in on the Dark Side of Color and find out what is being done to increase the after sales profits and don't be surprised if has been done long ago in some basement lab of a photographic company and of course, before its time.

  19. Language and counting: Some recent results

    Science.gov (United States)

    Bell, Garry

    1990-02-01

    It has long been recognised that the language of mathematics is an important variable in the learning of mathematics, and there has been useful work in isolating and describing the linkage. Steffe and his co-workers at Georgia, for example, (Steffe, von Glasersfeld, Richardson and Cobb, 1983) have suggested that young children may construct verbal countable items to count objects which are hidden from their view. Although there has been a surge of research interest in counting and early childhood mathematics, and in cultural differences in mathematics attainment, there has been little work reported on the linkage between culture as exemplified by language, and initial concepts of numeration. This paper reports on some recent clinical research with kindergarten children of European and Asian background in Australia and America. The research examines the influence that number naming grammar appears to have on young children's understandings of two-digit numbers and place value. It appears that Transparent Standard Number Word Sequences such as Japanese, Chinese and Vietnamese which follow the numerical representation pattern by naming tens and units in order ("two tens three"), may be associated with distinctive place value concepts which may support sophisticated mental algorithms.

  20. Counting Value Sets: Algorithm and Complexity

    CERN Document Server

    Cheng, Qi; Wan, Daqing

    2011-01-01

    Let $p$ be a prime. Given a polynomial in $\\F_{p^m}[x]$ of degree $d$ over the finite field $\\F_{p^m}$, one can view it as a map from $\\F_{p^m}$ to $\\F_{p^m}$, and examine the image of this map, also known as the value set. In this paper, we present the first non-trivial algorithm and the first complexity result on computing the cardinality of this value set. We show an elementary connection between this cardinality and the number of points on a family of varieties in affine space. We then apply Lauder and Wan's $p$-adic point-counting algorithm to count these points, resulting in a non-trivial algorithm for calculating the cardinality of the value set. The running time of our algorithm is $(pmd)^{O(d)}$. In particular, this is a polynomial time algorithm for fixed $d$ if $p$ is reasonably small. We also show that the problem is #P-hard when the polynomial is given in a sparse representation, $p=2$, and $m$ is allowed to vary, or when the polynomial is given as a straight-line program, $m=1$ and $p$ is allowe...

  1. Photon Counting Using Edge-Detection Algorithm

    Science.gov (United States)

    Gin, Jonathan W.; Nguyen, Danh H.; Farr, William H.

    2010-01-01

    New applications such as high-datarate, photon-starved, free-space optical communications require photon counting at flux rates into gigaphoton-per-second regimes coupled with subnanosecond timing accuracy. Current single-photon detectors that are capable of handling such operating conditions are designed in an array format and produce output pulses that span multiple sample times. In order to discern one pulse from another and not to overcount the number of incoming photons, a detection algorithm must be applied to the sampled detector output pulses. As flux rates increase, the ability to implement such a detection algorithm becomes difficult within a digital processor that may reside within a field-programmable gate array (FPGA). Systems have been developed and implemented to both characterize gigahertz bandwidth single-photon detectors, as well as process photon count signals at rates into gigaphotons per second in order to implement communications links at SCPPM (serial concatenated pulse position modulation) encoded data rates exceeding 100 megabits per second with efficiencies greater than two bits per detected photon. A hardware edge-detection algorithm and corresponding signal combining and deserialization hardware were developed to meet these requirements at sample rates up to 10 GHz. The photon discriminator deserializer hardware board accepts four inputs, which allows for the ability to take inputs from a quadphoton counting detector, to support requirements for optical tracking with a reduced number of hardware components. The four inputs are hardware leading-edge detected independently. After leading-edge detection, the resultant samples are ORed together prior to deserialization. The deserialization is performed to reduce the rate at which data is passed to a digital signal processor, perhaps residing within an FPGA. The hardware implements four separate analog inputs that are connected through RF connectors. Each analog input is fed to a high-speed 1

  2. Absolute Lymphocyte Count Is Not a Suitable Alternative to CD4 Count for Determining Initiation of Antiretroviral Therapy in Fiji

    Directory of Open Access Journals (Sweden)

    Dashika A. Balak

    2014-01-01

    Full Text Available Introduction. An absolute lymphocyte count is commonly used as an alternative to a CD4 count to determine initiation of antiretroviral therapy for HIV-infected individuals in Fiji when a CD4 count is unavailable. Methods. We conducted a retrospective analysis of laboratory results of HIV-infected individuals registered at all HIV clinics in Fiji. Results. Paired absolute lymphocyte and CD4 counts were available for 101 HIV-infected individuals, and 96% had a CD4 count of ≤500 cells/mm3. Correlation between the counts in individuals was poor (Spearman rank correlation r=0.5. No absolute lymphocyte count could be determined in this population as a suitable surrogate for a CD4 count of either 350 cells/mm3 or 500 cells/mm3. The currently used absolute lymphocyte count of ≤2300 cells/μL had a positive predictive value of 87% but a negative predictive value of only 17% for a CD4 of ≤350 cells/mm3 and if used as a surrogate for a CD4 of ≤500 cells/mm3 it would result in all HIV-infected individuals receiving ART including those not yet eligible. Weight, CD4 count, and absolute lymphocyte count increased significantly at 3 months following ART initiation. Conclusions. Our findings do not support the use of absolute lymphocyte count to determine antiretroviral therapy initiation in Fiji.

  3. Atomic and molecular manipulation

    CERN Document Server

    Mayne, Andrew J

    2011-01-01

    Work with individual atoms and molecules aims to demonstrate that miniaturized electronic, optical, magnetic, and mechanical devices can operate ultimately even at the level of a single atom or molecule. As such, atomic and molecular manipulation has played an emblematic role in the development of the field of nanoscience. New methods based on the use of the scanning tunnelling microscope (STM) have been developed to characterize and manipulate all the degrees of freedom of individual atoms and molecules with an unprecedented precision. In the meantime, new concepts have emerged to design molecules and substrates having specific optical, mechanical and electronic functions, thus opening the way to the fabrication of real nano-machines. Manipulation of individual atoms and molecules has also opened up completely new areas of research and knowledge, raising fundamental questions of "Optics at the atomic scale", "Mechanics at the atomic scale", Electronics at the atomic scale", "Quantum physics at the atomic sca...

  4. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    2000-01-01

    This fifth volume of the successful series Advances in Atomic Spectroscopy continues to discuss and investigate the area of atomic spectroscopy.It begins with a description of the use of various atomic spectroscopic methods and applications of speciation studies in atomic spectroscopy. The emphasis is on combining atomic spectroscopy with gas and liquid chromatography. In chapter two the authors describe new developments in tunable lasers and the impact they will have on atomic spectroscopy. The traditional methods of detection, such as photography and the photomultiplier, and how they are being replaced by new detectors is discussed in chapter three. The very active area of glow discharge atomic spectrometry is presented in chapter four where, after a brief introduction and historical review, the use of glow discharge lamps for atomic spectroscopy and mass spectrometry are discussed. Included in this discussion is geometry and radiofrequency power. The future of this source in atomic spectroscopy is also dis...

  5. Improving EWMA Plans for Detecting Unusual Increases in Poisson Counts

    Directory of Open Access Journals (Sweden)

    R. S. Sparks

    2009-01-01

    adaptive exponentially weighted moving average (EWMA plan is developed for signalling unusually high incidence when monitoring a time series of nonhomogeneous daily disease counts. A Poisson transitional regression model is used to fit background/expected trend in counts and provides “one-day-ahead” forecasts of the next day's count. Departures of counts from their forecasts are monitored. The paper outlines an approach for improving early outbreak data signals by dynamically adjusting the exponential weights to be efficient at signalling local persistent high side changes. We emphasise outbreak signals in steady-state situations; that is, changes that occur after the EWMA statistic had run through several in-control counts.

  6. Counting efficiency of the lung monitor for sup 2 sup 4 sup 1 Am

    CERN Document Server

    Kinase, S; Sekiguchi, M

    2003-01-01

    The counting efficiencies of two lung monitor systems, phoswich detector system and germanium detector system, were measured for lungs and liver loaded with sup 2 sup 4 sup 1 Am in the Japan Atomic Energy Research Institute (JAERI) phantom. It was found that the germanium detector system for sup 2 sup 4 sup 1 Am loaded lungs counting gives the full-energy peak predominated by the absorption of the gamma-ray photon in a single photoelectric interaction and is less sensitive to sup 2 sup 4 sup 1 Am loaded liver. The sup 2 sup 4 sup 1 Am loaded lung activities could be reasonably estimated using germanium detector system rather than phoswich detector system.

  7. Enumeration of islets by nuclei counting and light microscopic analysis.

    Science.gov (United States)

    Pisania, Anna; Papas, Klearchos K; Powers, Daryl E; Rappel, Michael J; Omer, Abdulkadir; Bonner-Weir, Susan; Weir, Gordon C; Colton, Clark K

    2010-11-01

    Islet enumeration in impure preparations by conventional dithizone staining and visual counting is inaccurate and operator dependent. We examined nuclei counting for measuring the total number of cells in islet preparations, and we combined it with morphological analysis by light microscopy (LM) for estimating the volume fraction of islets in impure preparations. Cells and islets were disrupted with lysis solution and shear, and accuracy of counting successively diluted nuclei suspensions was verified with (1) visual counting in a hemocytometer after staining with crystal violet, and automatic counting by (2) aperture electrical resistance measurement and (3) flow cytometer measurement after staining with 7-aminoactinomycin-D. DNA content averaged 6.5 and 6.9 pg of DNA per cell for rat and human islets, respectively, in agreement with literature estimates. With pure rat islet preparations, precision improved with increasing counts, and samples with about ≥160 islets provided a coefficient of variation of about 6%. Aliquots of human islet preparations were processed for LM analysis by stereological point counting. Total nuclei counts and islet volume fraction from LM analysis were combined to obtain the number of islet equivalents (IEs). Total number of IE by the standard method of dithizone staining/manual counting was overestimated by about 90% compared with LM/nuclei counting for 12 freshly isolated human islet research preparations. Nuclei counting combined with islet volume fraction measurements from LM is a novel method for achieving accurate islet enumeration. PMID:20697375

  8. THE ORNL ATOM PROBE

    OpenAIRE

    Miller, M

    1986-01-01

    The ORNL Atom Probe is a microanalytical tool for studies in materials science. The instrument is a combination of a customized version of the vacuum system of the VG FIM-100 atom probe, an ORNL-designed microcomputer-controlled digital timing system, and a double curved CEMA Imaging Atom Probe detector. The atom probe combines four instruments into one - namely a field ion microscope, an energy compensated time-of-flight mass spectrometer, an imaging atom probe, and a pulsed laser atom probe.

  9. Analysis of General Power Counting Rules in Effective Field Theory

    CERN Document Server

    Gavela, B M; Manohar, A V; Merlo, L

    2016-01-01

    We derive the general counting rules for a quantum effective field theory (EFT) in $\\mathsf{d}$ dimensions. The rules are valid for strongly and weakly coupled theories, and predict that all kinetic energy terms are canonically normalized. They determine the energy dependence of scattering cross sections in the range of validity of the EFT expansion. The size of cross sections is controlled by the $\\Lambda$ power counting of EFT, not by chiral counting, even for chiral perturbation theory ($\\chi$PT). The relation between $\\Lambda$ and $f$ is generalized to $\\mathsf{d}$ dimensions. We show that the naive dimensional analysis $4\\pi$ counting is related to $\\hbar$ counting. The EFT counting rules are applied to $\\chi$PT, to Standard Model EFT and to the non-trivial case of Higgs EFT, which combines the $\\Lambda$ and chiral counting rules within a single theory.

  10. Method for effective dead time measurement in counting systems

    Energy Technology Data Exchange (ETDEWEB)

    Vinagre, F.L.R. E-mail: fleonor@saturno.fis.uc.pt; Conde, C.A.N

    2001-04-21

    The counting losses introduced by the dead time of a counting system are a limiting factor in counting measurements. The purpose of this work is to report an efficient method for the measurement of the effective dead time of a counting system and to characterize its dead time behavior, providing a way to investigate each experimental situation. The method, which we designate as Delayed and Mixed Pulses method, is based on the artificial piling-up of detector pulses with electronic pulses delayed by a specific time interval. It is applicable to the measurement of the effective dead time of a counting system, including both pile-up effects and the dead time characteristics of the elements of the counting chain. With counting systems relying on gaseous radiation detectors, we achieved a standard uncertainty of about 5-10% in the dead times measured.

  11. Optimization of high count rate event counting detector with Microchannel Plates and quad Timepix readout

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu; Vallerga, J.V.; McPhate, J.B.; Siegmund, O.H.W.

    2015-07-01

    Many high resolution event counting devices process one event at a time and cannot register simultaneous events. In this article a frame-based readout event counting detector consisting of a pair of Microchannel Plates and a quad Timepix readout is described. More than 10{sup 4} simultaneous events can be detected with a spatial resolution of ~55 µm, while >10{sup 3} simultaneous events can be detected with <10 µm spatial resolution when event centroiding is implemented. The fast readout electronics is capable of processing >1200 frames/sec, while the global count rate of the detector can exceed 5×10{sup 8} particles/s when no timing information on every particle is required. For the first generation Timepix readout, the timing resolution is limited by the Timepix clock to 10–20 ns. Optimization of the MCP gain, rear field voltage and Timepix threshold levels are crucial for the device performance and that is the main subject of this article. These devices can be very attractive for applications where the photon/electron/ion/neutron counting with high spatial and temporal resolution is required, such as energy resolved neutron imaging, Time of Flight experiments in lidar applications, experiments on photoelectron spectroscopy and many others.

  12. Modeling Repeated Count Data: Some Extensions of the Rasch Poisson Counts Model.

    Science.gov (United States)

    Duijn, Marijtje A. J. van; Jansen, Margo G. H.

    1995-01-01

    The Rasch Poisson Counts Model, a unidimensional latent trait model for tests that postulates that intensity parameters are products of test difficulty and subject ability parameters, is expanded into the Dirichlet-Gamma-Poisson model that takes into account variation between subjects and interaction between subjects and tests. (SLD)

  13. Modeling Repeated Count Data : Some Extensions of the Rasch Poisson Counts Model

    NARCIS (Netherlands)

    van Duijn, M.A.J.; Jansen, Margo

    1995-01-01

    We consider data that can be summarized as an N X K table of counts-for example, test data obtained by administering K tests to N subjects. The cell entries y(ij) are assumed to be conditionally independent Poisson-distributed random variables, given the NK Poisson intensity parameters mu(ij). The R

  14. Total leucocyte count, C-reactive protein and neutrophil count: Diagnostic Aid in acute appendicitis

    Directory of Open Access Journals (Sweden)

    Shafi Sheikh

    2009-01-01

    Full Text Available Background/Aim: Acute appendicitis is one of the most common acute intraabdominal affections seen in surgical departments, which can be treated easily if an accurate diagnosis is made in time. Otherwise, delay in diagnosis and treatment can lead to diffuse peritonitis. Materials and Methods: A study was conducted on 110 patients who were operated for acute appendicitis to determine the role and predictive value of the total leucocyte count (TLC, C-reactive protein (CRP and percentage of neutrophil count in the diagnosis of acute appendicitis. Preoperative TLC, CRP and percentage of neutrophil count were determined and were compared with the results of the histopathology of the removed appendix. Results: Of all the patients studied, 92 had histopathologically positive appendicitis. The TLC was found to be significantly high in 90 patients who proved to have acute appendicitis, whereas CRP was high in only 88 patients and neutrophil percentage was raised in 91; four had a normal CRP level. Thus, TLC had a sensitivity, specificity and positive predictive value of 97.82%, 55.55% and 91.8%, respectively. CRP had a sensitivity, specificity and positive predictive value of 95.6%, 77.77% and 95.6% respectively. Percentage of neutrophil count had a sensitivity, specificity and positive predictive value of 98.9%, 38.88% and 89.21%, respectively. When used in combination, there was a marked improvement in the specificity and the positive predictive value to 88.04% and 98.7%, respectively. Conclusion: The inflammatory markers, i.e., TLC, CRP and neutrophil count can be helpful in the diagnosis when measured together as this increases their specificity and positive predictive value.

  15. EMILIA, the LS counting efficiency for electron-capture and capture-gamma emitters

    Science.gov (United States)

    Grau Carles, A.

    2006-01-01

    This version includes new aspects that improve the computation of the counting efficiency for each one of the three available atomic rearrangement detection models (i.e., KLM, KL 1L 2L 3M and KLMN). The first modification involves a correction algorithm that simulates the non-linear response of the detector to photoionization for low-energy X-ray photons. Although this correction has the inconvenience of substantially increasing the number of atomic rearrangement detection pathways, the computed counting efficiency for low- Z nuclides is reduced by 2% for moderate quenching in agreement with experiment. The program also simulates how the addition of extra components, such as a quencher or aqueous solutions, affects the counting efficiency. Since the CIEMAT/NIST method requires identical ionization quench functions for the electron-capture nuclide and the tracer, the computation of the counting efficiency for 3H, the low-energy beta-ray emitter commonly used as tracer, is included in the program as an option. Program summaryTitle of program:EMILIA Catalogue identifier:ADWK Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADWK Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing previsions: none Computers: revisions: any IBM PC compatible with 80386 or higher Intel processors Operating systems under which the program has been tested:MS-DOS and higher systems Programming language used:FORTRAN 77 Memory required to execute with typical data: 253 kword No. of bits in a word: 32 No. of lines in distributed program, including test data, etc.:7147 No. of bytes in distributed program, including test data, etc.:74 776 Distribution format:tar.gz Nature of the physical problem: The determination of radioactivity in liquid samples of electron-capture nuclides is demanded in radiation physics, radiation protection, dosimetry, radiobiology and nuclear medicine. The CIEMAT/NIST method has proved to be suitable for radionuclide

  16. Counting and Arithmetic of the Inca

    Directory of Open Access Journals (Sweden)

    Ximena Catepillán

    2012-08-01

    Full Text Available The Inca Empire - the greatest pre-Columbian empire on the American continent - extended from Ecuador to central Chile for more than five thousand miles. Its capital was Cuzco established in the high Peruvian Andes. This highly advanced civilization developed a counting system used to run the empire - in particular, to build the 14,000 mile road structure and monumental architecture. Some of the algorithms believed to be used by the Inca to do computations using a yupana, an ancient calculating device, will be presented, as well as classroom activities for the course “Mathematics in Non-European Cultures” for non Mathematics and Science majors offered at Millersville University of Pennsylvania.

  17. Spectral shaping for photon counting digital mammography

    International Nuclear Information System (INIS)

    The spectral shaping properties of conventional filters have been evaluated for a photon counting digital mammography system, and the result has been compared with the theoretical spectrum from a multi-prism X-ray lens (MPL). The absorption filters and the MPL were evaluated using a theoretical model of the system which has been verified experimentally. The spectral shaping performance is quantified with the spectral quantum efficiency (SQE), calculated as the polychromatic signal-difference-to-noise ratio (SDNR) squared over the optimal monochromatic SDNR squared at the same average glandular dose. The MPL increases the SQE by 25% compared to the investigated absorption filter when compared with a Tungsten anode. This translates into a potential dose reduction of 20% at maintained SDNR

  18. Counting lattice animals in high dimensions

    International Nuclear Information System (INIS)

    We present an implementation of Redelemeier's algorithm for the enumeration of lattice animals in high-dimensional lattices. The implementation is lean and fast enough to allow us to extend the existing tables of animal counts, perimeter polynomials and series expansion coefficients in d-dimensional hypercubic lattices for 3 ≤ d ≤ 10. From the data we compute formulae for perimeter polynomials for lattice animals of size n ≤ 11 in arbitrary dimension d. When amended by combinatorial arguments, the new data suffice to yield explicit formulae for the number of lattice animals of size n ≤ 14 and arbitrary d. We also use the enumeration data to compute numerical estimates for growth rates and exponents in high dimensions that agree very well with Monte Carlo simulations and recent predictions from field theory

  19. The bispectrum of relativistic galaxy number counts

    CERN Document Server

    Di Dio, Enea; Marozzi, Giovanni; Montanari, Francesco

    2016-01-01

    Starting from the relativistic galaxy number counts to second order in cosmological perturbation theory which we have determined in a previous paper, we discuss the dominant terms on sub-Hubble scales and on intermediate to large redshifts. In particular, we determine their contribution to the bispectrum. In addition to the terms already known from Newtonian second order perturbation theory, we find that there are a series of additional `lensing-like' terms which contribute to the bispectrum. We derive analytical expressions for the full leading order bispectrum and we evaluate it numerically for different configurations, indicating how they can be measured with upcoming surveys. In particular, the new `lensing-like' terms are not negligible within large window functions and even dominate the bispectrum at well separated redshifts. This offers us the possibility to measure them in future surveys.

  20. Counting whales in a challenging, changing environment.

    Science.gov (United States)

    Williams, R; Kelly, N; Boebel, O; Friedlaender, A S; Herr, H; Kock, K-H; Lehnert, L S; Maksym, T; Roberts, J; Scheidat, M; Siebert, U; Brierley, A S

    2014-01-01

    Estimating abundance of Antarctic minke whales is central to the International Whaling Commission's conservation and management work and understanding impacts of climate change on polar marine ecosystems. Detecting abundance trends is problematic, in part because minke whales are frequently sighted within Antarctic sea ice where navigational safety concerns prevent ships from surveying. Using icebreaker-supported helicopters, we conducted aerial surveys across a gradient of ice conditions to estimate minke whale density in the Weddell Sea. The surveys revealed substantial numbers of whales inside the sea ice. The Antarctic summer sea ice is undergoing rapid regional change in annual extent, distribution, and length of ice-covered season. These trends, along with substantial interannual variability in ice conditions, affect the proportion of whales available to be counted by traditional shipboard surveys. The strong association between whales and the dynamic, changing sea ice requires reexamination of the power to detect trends in whale abundance or predict ecosystem responses to climate change. PMID:24622821

  1. Combining cluster number counts and galaxy clustering

    CERN Document Server

    Lacasa, Fabien

    2016-01-01

    We present a detailed modelling of the joint covariance matrix between cluster number counts and the galaxy angular power spectrum. To this end, we use a Halo Model framework complemented by a Halo Occupation Distribution model (HOD), and we work in full-sky. We demonstrate the importance of accounting for non-Gaussianity to produce accurate covariance predictions, as the Gaussian part of the covariance can in fact become subdominant in certain configurations. We discuss in particular the case of the super-sample covariance (SSC), including the effects of galaxy shot-noise, halo second order bias and non-local bias, and demonstrating interesting mathematical properties. Using the joint covariance matrix and a Fisher matrix methodology, we examine the prospects of combining these two probes to constrain cosmological and HOD parameters. We find that the combination indeed results in noticeable better constraints, in particular because the cross-covariance introduces a synergy between the probes on small scales....

  2. 13/2 ways to count curves

    CERN Document Server

    Pandharipande, R

    2011-01-01

    In the past 20 years, compactifications of the families of curves in algebraic varieties X have been studied via stable maps, Hilbert schemes, stable pairs, unramified maps, and stable quotients. Each path leads to a different enumeration of curves. A common thread is the use of a 2-term deformation/obstruction theory to define a virtual fundamental class. The richest geometry occurs when X is a nonsingular projective variety of dimension 3. We survey here the 13/2 principal ways to count curves with special attention to the 3-fold case. The different theories are linked by a web of conjectural relationships which we highlight. Our goal is to provide a guide for graduate students looking for an elementary route into the subject.

  3. Application Guide to Neutron Multiplicity Counting

    Energy Technology Data Exchange (ETDEWEB)

    D. G. Langner; J. E. Stewart; M. M. Pickrell; M. S. Krick; N. Ensslin; W. C. Harker

    1998-11-01

    This document is intended to serve as a comprehensive applications guide to passive neutron multiplicity counting, a new nondestructive assay (NDA) technique developed over the past ten years. The document describes the principles of multiplicity counter design, electronics, and mathematics. Existing counters in Department of Energy (DOE) facilities are surveyed, and their operating requirements and procedures and defined. Current applications to plutonium material types found in DOE facilities are described, and estimates of the expected assay precision and bias are given. Lastly, guidelines for multiplicity counter selection and procurement are summarized. The document also includes a detailed collection of references on passive neutron coincidence and multiplicity publications over the last ten to fifteen years.

  4. A generalized model for coincidence counting

    International Nuclear Information System (INIS)

    The aim of this paper is to provide a description of the multiplicative processes associated with coincidence counting techniques, for example in the NDA of plutonium bearing materials. The model elucidates both the physical processes and the underlying mathematical formalism in a relatively simple but comprehensive way. In particular, it includes the effect of absorption by impurities or poisons, as well as that of neutron leakage on a parallel basis to the treatment of induced fission itself. The work thus parallels and generalizes the methods of Boehnel of Hage and Cifarelli, and more recently of Yanjushkin. This paper introduces the concept of a dual probability generating function to account for both the basic physical multiplication phenomena, as well as the detection phenomena. The underlying approach extends the idea of a simple probability generating function, due to De Moivre. The basic mathematical background may be found, for example, in Feller 1966

  5. Weighted power counting and chiral dimensional regularization

    CERN Document Server

    Anselmi, Damiano

    2014-01-01

    We define a modified dimensional-regularization technique that overcomes several difficulties of the ordinary technique, and is specially designed to work efficiently in chiral and parity violating quantum field theories, in arbitrary dimensions greater than 2. When the dimension of spacetime is continued to complex values, spinors, vectors and tensors keep the components they have in the physical dimension, therefore the gamma matrices are the standard ones. Propagators are regularized with the help of evanescent higher-derivative kinetic terms, which are of Majorana type in the case of chiral fermions. If the new terms are organized in a clever way, weighted power counting provides an efficient control on the renormalization of the theory, and allows us to show that the resulting chiral dimensional regularization is consistent to all orders. The new technique considerably simplifies the proofs of properties that hold to all orders, and makes them suitable to be generalized to wider classes of models. Typica...

  6. Number Counts and Dynamical Vacuum Cosmologies

    CERN Document Server

    Devi, N Chandrachani; Carneiro, S; Alcaniz, J S

    2014-01-01

    We study non-linear structure formation in an interacting model of the dark sector of the Universe in which the dark energy density decays linearly with the Hubble parameter, $\\rho_{\\Lambda} \\propto H$, leading to a constant-rate creation of cold dark matter. We derive all relevant expressions to calculate the mass function and the cluster number density using the Sheth-Torman formalism and show that the effect of the interaction process is to increase the number of bound structures of large masses ($M \\gtrsim 10^{14} M_{\\odot}h^{-1}$) when compared to the standard $\\Lambda$CDM model. Since these models are not reducible to each other, this number counts signature can in principle be tested in future surveys.

  7. Optics study of liquid scintillation counting systems

    International Nuclear Information System (INIS)

    Optics is a key issue in the development of any liquid scintillation counting (LSC) system. Light emission in the scintillating solution, transmission through the vial and reflector design are some aspects that need to be considered in detail. This paper describes measurements and calculations carried out to optimise these factors for the design of a new family of LSC counters. Measurements of the light distribution emitted by a scintillation vial were done by autoradiographs of cylindrical vials made of various materials and results were compared to those obtained by direct measurements of the light distribution made by scanning the vial with a photomultiplier tube. Calculations were also carried out to study the light transmission in the vial and the optimal design of the reflector for a system with one photomultiplier tube. (Author)

  8. Tritium counting in the Geiger region

    International Nuclear Information System (INIS)

    In the course of research on exchange, the authors found it necessary to perfect a method of counting tritium in the form of a gaseous halogenated organic derivative. Special attention was paid to the design of a self-quenching counter operating in the Geiger region, for measuring the radiochemical concentration of tritium in methyl chloride. The effect of the nature and partial pressure of certain rare gases was determined. The effect of variation in the partial pressure of the methyl chloride was also ascertained. Finally, it was shown that the presence of small quantities of chlorine considerably increases the length of the plateau. The most interesting features discovered were: (a) A threshold at about 1200 V; (b) A plateau between 1400 and 2700 V; (c) A slope of less than 2% per 100 V; (d) A dead time of the order of 100 μs. There was no sign of any memory effect when using a stainless-steel cathode. (author)

  9. Number Counts and Non-Gaussianity

    CERN Document Server

    Shandera, Sarah; Scott, Pat; Galarza, Jhon Yana

    2013-01-01

    We describe a general procedure for using number counts of any object to constrain the probability distribution of the primordial fluctuations, allowing for generic weak non-Gaussianity. We apply this procedure to use limits on the abundance of primordial black holes and dark matter ultracompact minihalos (UCMHs) to characterize the allowed statistics of primordial fluctuations on very small scales. We present constraints on the power spectrum and the amplitude of the skewness for two different families of non-Gaussian distributions, distinguished by the relative importance of higher moments. Although primordial black holes probe the smallest scales, ultracompact minihalos provide significantly stronger constraints on the power spectrum and so are more likely to eventually provide small-scale constraints on non-Gaussianity.

  10. Single-atom detection of ytterbium by selective laser excitation field ionization from Rydberg states

    International Nuclear Information System (INIS)

    Detection of single atoms Yb has been achieved using the method of electric-field ionization from the high-lying Rydberg states. Atoms of Yb in a beam were excited in three steps to a 17-p state by radiation of three pulsed dye lasers. The statistics of an atom's appearance in the interaction volume have been studied in the single-ion counting regime at low beam density

  11. Atomic and molecular structure

    International Nuclear Information System (INIS)

    This book is a textbook for an introductory course of atomic physics for students of chemistry. After an introduction to the mathematical and physical foundations the quantum mechanical theory of atoms is described starting from simple examples of quantum mechanics. Then the atomic structure and the chemical bending are extensively discussed. This book is also suited for physicists who are especially interested in the atomic structure and the theory of chemical reactions. (HSI)

  12. Atomic Scale Plasmonic Switch

    OpenAIRE

    Emboras, A.; Niegemann, J.; Ma, P; Haffner, C; Pedersen, A.; Luisier, M.; Hafner, C; Schimmel, T.; Leuthold, J.

    2016-01-01

    The atom sets an ultimate scaling limit to Moore’s law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocat...

  13. Atomizing nozzle and process

    Science.gov (United States)

    Anderson, Iver E.; Figliola, Richard S.; Molnar, Holly M.

    1992-06-30

    High pressure atomizing nozzle includes a high pressure gas manifold having a divergent expansion chamber between a gas inlet and arcuate manifold segment to minimize standing shock wave patterns in the manifold and thereby improve filling of the manifold with high pressure gas for improved melt atomization. The atomizing nozzle is especially useful in atomizing rare earth-transition metal alloys to form fine powder particles wherein a majority of the powder particles exhibit particle sizes having near-optimum magnetic properties.

  14. Antiprotonic Helium Atoms

    OpenAIRE

    Kartavtsev, O. I.

    1995-01-01

    Metastable antiprotonic helium atoms $^{3,4}\\! H\\! e\\bar pe$ have been discovered recently in experiments of the delayed annihilation of antiprotons in helium media. These exotic atoms survive for an enormous time (about tens of microseconds) and carry the extremely large total angular momentum $L\\sim 30-40$. The theoretical treatment of the intrinsic properties of antiprotonic helium atoms, their formation and collisions with atoms and molecules is discussed.

  15. Atoms Talking to SQUIDs

    OpenAIRE

    2011-01-01

    We present a scheme to couple trapped $^{87}$Rb atoms to a superconducting flux qubit through a magnetic dipole transition. We plan to trap atoms on the evanescent wave outside an ultrathin fiber to bring the atoms to less than 10 $\\mu$m above the surface of the superconductor. This hybrid setup lends itself to probing sources of decoherence in superconducting qubits. Our current plan has the intermediate goal of coupling the atoms to a superconducting LC resonator.

  16. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  17. Atomic Energy Control Act

    International Nuclear Information System (INIS)

    This act provides for the establishment of the Atomic Energy Control Board. The board is responsible for the control and supervision of the development, application and use of atomic energy. The board is also considered necessary to enable Canada to participate effectively in measures of international control of atomic energy

  18. Single atom electrochemical and atomic analytics

    Science.gov (United States)

    Vasudevan, Rama

    In the past decade, advances in electron and scanning-probe based microscopies have led to a wealth of imaging and spectroscopic data with atomic resolution, yielding substantial insight into local physics and chemistry in a diverse range of systems such as oxide catalysts, multiferroics, manganites, and 2D materials. However, typical analysis of atomically resolved images is limited, despite the fact that image intensities and distortions of the atoms from their idealized positions contain unique information on the physical and chemical properties inherent to the system. Here, we present approaches to data mine atomically resolved images in oxides, specifically in the hole-doped manganite La5/8Ca3/8MnO3, on epitaxial films studied by in-situ scanning tunnelling microscopy (STM). Through application of bias to the STM tip, atomic-scale electrochemistry is demonstrated on the manganite surface. STM images are then further analyzed through a suite of algorithms including 2D autocorrelations, sliding window Fourier transforms, and others, and can be combined with basic thermodynamic modelling to reveal relevant physical and chemical descriptors including segregation energies, existence and strength of atomic-scale diffusion barriers, surface energies and sub-surface chemical species identification. These approaches promise to provide tremendous insights from atomically resolved functional imaging, can provide relevant thermodynamic parameters, and auger well for use with first-principles calculations to yield quantitative atomic-level chemical identification and structure-property relations. This research was sponsored by the Division of Materials Sciences and Engineering, BES, DOE. Research was conducted at the Center for Nanophase Materials Sciences, which also provided support and is a DOE Office of Science User Facility.

  19. Atomic swelling upon compression

    CERN Document Server

    Dolmatov, V K

    2012-01-01

    The hydrogen atom under the pressure of a spherical penetrable confinement potential of a decreasing radius $r_{0}$ is explored, as a case study. A novel counter-intuitive effect of atomic swelling rather than shrinking with decreasing $r_{0}$ is unraveled, when $r_{0}$ reaches, and remains smaller than, a certain critical value. Upon swelling, the size of the atom is shown to increase by an order of magnitude, or more, compared to the size of the free atom. Examples of changes of photoabsorption properties of confined hydrogen atom upon its swelling are uncovered and demonstrated.

  20. Total lymphocyte count as a substitute to cd4 count in management of hiv infected individuals in resource limited society

    International Nuclear Information System (INIS)

    Pakistan is a resource limited society and gold standard parameters to monitor HIV disease activity are very costly. The objective of the study was to evaluate total lymphocyte count (TLC) as a surrogate to CD4 count to monitor disease activity in HIV/AIDS in resource limited society. Methods: This cross sectional study was carried out at HIV/AIDS treatment centre, Pakistan Institute of Medical Sciences (PIMS), Islamabad. A total of seven hundred and seventy four (774) HIV positive patients were enrolled in this study, and their CD4 count and total lymphocyte count were checked to find any correlation between the two by using Spearman ranked correlation coefficient. Results: The mean CD4 count was (434.30 ± 269.23), with minimum CD4 count of (9.00), and maximum of (1974.00). The mean total lymphocyte count (TLC) was (6764.0052 ± 2364.02) with minimum TLC (1200.00) and maximum TLC was (20200.00). Using the Pearson's correlation (r) there was a significant and positive correlation between TLC and CD4 count. (r2=0.127 and p=0.000) at 0.01 level. Conclusion: Our study showed a significant positive correlation between CD4 count and total lymphocyte count (TLC), so TLC can be used as a marker of disease activity in HIV infected patients. (author)

  1. Image-based red cell counting for wild animals blood.

    Science.gov (United States)

    Mauricio, Claudio R M; Schneider, Fabio K; Dos Santos, Leonilda Correia

    2010-01-01

    An image-based red blood cell (RBC) automatic counting system is presented for wild animals blood analysis. Images with 2048×1536-pixel resolution acquired on an optical microscope using Neubauer chambers are used to evaluate RBC counting for three animal species (Leopardus pardalis, Cebus apella and Nasua nasua) and the error found using the proposed method is similar to that obtained for inter observer visual counting method, i.e., around 10%. Smaller errors (e.g., 3%) can be obtained in regions with less grid artifacts. These promising results allow the use of the proposed method either as a complete automatic counting tool in laboratories for wild animal's blood analysis or as a first counting stage in a semi-automatic counting tool. PMID:21096766

  2. Ionization of atomic oxygen by protons

    International Nuclear Information System (INIS)

    A crossed-beam technique incorporating time-of-flight analysis and coincidence counting of the collision products, recently used in this laboratory to study one-electron capture in collisions of H+ ions with ground-state oxygen atoms, has been adapted to allow measurements of the corresponding cross sections for ionization for the first time. Cross sections for the single ionization of O atoms have been determined within the range 34-100 keV. These cross sections pass through a peak value at an energy of about 60 keV. At higher energies, the process of ionization rather than electron capture becomes the main source of O+ production. On+ formation for n > 2 was too small to detect in the energy range considered. It is also shown that although production of O2+ through transfer ionization is quite significant, the yield of O2+ from pure ionization is unimportant. (author)

  3. A mind you can count on: validating breath counting as a behavioral measure of mindfulness

    OpenAIRE

    Levinson, Daniel B.; Eli Lucus Stoll; Sonam Dolker Kindy; Hillary Leah Merry; Davidson, Richard J.

    2014-01-01

    Mindfulness practice of present moment awareness promises many benefits, but has eluded rigorous behavioral measurement. To date, research has relied on self-reported mindfulness or heterogeneous mindfulness trainings to infer skillful mindfulness practice and its effects. In four independent studies with over 400 total participants, we present the first construct validation of a behavioral measure of mindfulness, breath counting. We found it was reliable, correlated with self-reported mi...

  4. Counting in the dark: Non-intrusive laser scanning for population counting and identifying roosting bats

    OpenAIRE

    Suzanna Noor Azmy; Shahrul Anuar Mohd Sah; Nur Juliani Shafie; Azman Ariffin; Zulkepli Majid; Muhamad Nor Akmal Ismail; Mohd Shahir Shamsir

    2012-01-01

    Population surveys and species recognition for roosting bats are either based on capture, sight or optical-mechanical count methods. However, these methods are intrusive, are tedious and, at best, provide only statistical estimations. Here, we demonstrated the successful use of a terrestrial Light Detection and Ranging (LIDAR) laser scanner for remotely identifying and determining the exact population of roosting bats in caves. LIDAR accurately captured the 3D features of the roosting bats an...

  5. The lost castle of Count Rodrigo Gonzalez

    Directory of Open Access Journals (Sweden)

    Ehrlich, Michael

    2015-12-01

    Full Text Available This article suggests that a castle called Toron built in 1137 by Count Rodrigo of Lara, and granted to the Templar Order was in Summil, where remains of a Crusader castles are still visible (ca. 25 km from Ascalon, in south west Israel. This opinion opposes a consensual view that the castle built by Count Rodrigo was in Latrun, midway between Tel-Aviv and Jerusalem. This identifi cation is based on names’ similarity and on the universal opinion that Latrun was a Templar castle. In this article it is demonstrated that the geographic setting of Summil fi ts the Count’s castle, whereas Latrun does not; that Toron was a common name in the Crusader Kingdom; and, moreover, it is not certain that Latrun was a Templar castle. The article also suggest that there was a village near the castle, called Casale Sancti Salvatoris, and also discusses Frankish fortifi cation and settlement policy during the twelfth century.Este artículo sugiere que un castillo llamado Toron, construido el año 1137 por el conde Rodrigo González de Lara, y que fue luego otorgado a la orden del Temple, estaba en Summil, donde todavía permanecen las ruinas de un castillo de los cruzados (a unos 25 km de Ascalon, en el sudoeste de Israel. Esta opinión se contrapone a la tesis general que sostiene que el castillo construido por el conde estuvo situado en Latrun, a medio camino entre Tel-Aviv y Jerusalén. Una identificación basada en la similitud de nombres y en la común opinión que Latrun era un castillo templario. En este estudio se demuestra que la ubicación geográfica de Summil encaja con la del castillo del conde, mientras que Latrun no lo hace; que Toron fue un nombre habitual en el reino cruzado y que, por otra parte, no es cierto que Latrun fuera un castillo templario. Se sugiere también que cerca del castillo de Summil existía un pueblo llamado casale Sancti Salvatoris, analizándose asimismo la política de fortificación y colonización llevada a cabo por

  6. Statistical mapping of count survey data

    Science.gov (United States)

    Royle, J. Andrew; Link, W.A.; Sauer, J.R.

    2002-01-01

    We apply a Poisson mixed model to the problem of mapping (or predicting) bird relative abundance from counts collected from the North American Breeding Bird Survey (BBS). The model expresses the logarithm of the Poisson mean as a sum of a fixed term (which may depend on habitat variables) and a random effect which accounts for remaining unexplained variation. The random effect is assumed to be spatially correlated, thus providing a more general model than the traditional Poisson regression approach. Consequently, the model is capable of improved prediction when data are autocorrelated. Moreover, formulation of the mapping problem in terms of a statistical model facilitates a wide variety of inference problems which are cumbersome or even impossible using standard methods of mapping. For example, assessment of prediction uncertainty, including the formal comparison of predictions at different locations, or through time, using the model-based prediction variance is straightforward under the Poisson model (not so with many nominally model-free methods). Also, ecologists may generally be interested in quantifying the response of a species to particular habitat covariates or other landscape attributes. Proper accounting for the uncertainty in these estimated effects is crucially dependent on specification of a meaningful statistical model. Finally, the model may be used to aid in sampling design, by modifying the existing sampling plan in a manner which minimizes some variance-based criterion. Model fitting under this model is carried out using a simulation technique known as Markov Chain Monte Carlo. Application of the model is illustrated using Mourning Dove (Zenaida macroura) counts from Pennsylvania BBS routes. We produce both a model-based map depicting relative abundance, and the corresponding map of prediction uncertainty. We briefly address the issue of spatial sampling design under this model. Finally, we close with some discussion of mapping in relation to

  7. Cascaded systems analysis of photon counting detectors

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Zbijewski, W.; Gang, G.; Stayman, J. W. [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Taguchi, K.; Carrino, J. A. [Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Lundqvist, M.; Fredenberg, E. [Philips Healthcare, Solna 171 41 (Sweden); Siewerdsen, J. H., E-mail: jeff.siewerdsen@jhu.edu [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21205 (United States)

    2014-10-15

    Purpose: Photon counting detectors (PCDs) are an emerging technology with applications in spectral and low-dose radiographic and tomographic imaging. This paper develops an analytical model of PCD imaging performance, including the system gain, modulation transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). Methods: A cascaded systems analysis model describing the propagation of quanta through the imaging chain was developed. The model was validated in comparison to the physical performance of a silicon-strip PCD implemented on an experimental imaging bench. The signal response, MTF, and NPS were measured and compared to theory as a function of exposure conditions (70 kVp, 1–7 mA), detector threshold, and readout mode (i.e., the option for coincidence detection). The model sheds new light on the dependence of spatial resolution, charge sharing, and additive noise effects on threshold selection and was used to investigate the factors governing PCD performance, including the fundamental advantages and limitations of PCDs in comparison to energy-integrating detectors (EIDs) in the linear regime for which pulse pileup can be ignored. Results: The detector exhibited highly linear mean signal response across the system operating range and agreed well with theoretical prediction, as did the system MTF and NPS. The DQE analyzed as a function of kilovolt (peak), exposure, detector threshold, and readout mode revealed important considerations for system optimization. The model also demonstrated the important implications of false counts from both additive electronic noise and charge sharing and highlighted the system design and operational parameters that most affect detector performance in the presence of such factors: for example, increasing the detector threshold from 0 to 100 (arbitrary units of pulse height threshold roughly equivalent to 0.5 and 6 keV energy threshold, respectively), increased the f{sub 50} (spatial

  8. Leukocyte nucleus segmentation and nucleus lobe counting

    Directory of Open Access Journals (Sweden)

    Zheng Zong-Han

    2010-11-01

    Full Text Available Abstract Background Leukocytes play an important role in the human immune system. The family of leukocytes is comprised of lymphocytes, monocytes, eosinophils, basophils, and neutrophils. Any infection or acute stress may increase or decrease the number of leukocytes. An increased percentage of neutrophils may be caused by an acute infection, while an increased percentage of lymphocytes can be caused by a chronic bacterial infection. It is important to realize an abnormal variation in the leukocytes. The five types of leukocytes can be distinguished by their cytoplasmic granules, staining properties of the granules, size of cell, the proportion of the nuclear to the cytoplasmic material, and the type of nucleolar lobes. The number of lobes increased when leukemia, chronic nephritis, liver disease, cancer, sepsis, and vitamin B12 or folate deficiency occurred. Clinical neutrophil hypersegmentation has been widely used as an indicator of B12 or folate deficiency.Biomedical technologists can currently recognize abnormal leukocytes using human eyes. However, the quality and efficiency of diagnosis may be compromised due to the limitations of the biomedical technologists' eyesight, strength, and medical knowledge. Therefore, the development of an automatic leukocyte recognition system is feasible and necessary. It is essential to extract the leukocyte region from a blood smear image in order to develop an automatic leukocyte recognition system. The number of lobes increased when leukemia, chronic nephritis, liver disease, cancer, sepsis, and vitamin B12 or folate deficiency occurred. Clinical neutrophil hypersegmentation has been widely used as an indicator of B12 or folate deficiency. Results The purpose of this paper is to contribute an automatic leukocyte nuclei image segmentation method for such recognition technology. The other goal of this paper is to develop the method of counting the number of lobes in a cell nucleus. The experimental results

  9. Single Atom Plasmonic Switch

    CERN Document Server

    Emboras, Alexandros; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most - a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ration of 10 dB and operation at room temperature with femtojoule (fJ) power consumption for a single switch operation. This demonstration of a CMOS compatible, integrated quantum device allowing to control photons at the single-atom level opens intriguing perspectives for a fully i...

  10. Excited atoms. Vozbuzhdennye atomy

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, B.M.

    1982-01-01

    An examination is made of the properties of excited atoms and molecules, the processes of their formation in a gas and plasma, and the diffusion of excited atoms in a gas. A presentation is made of the processes in which excited and metastable atoms and molecules in a gas are destroyed upon collision with electrons, atoms, and molecules. A study is made of the relaxation of excited states during collisions - excitation transfer, depolarization, transitions between fine structure states, etc. Information is given on ionization that includes the participation of excited atoms - the Penning process, associative ionization. An examination is made of highly excited states of atoms and the processes that take place during their participation. The book is intended for personnel in the area of physics and chemistry of plasma, atomic and molecular physics, chemical physics as well as in allied areas of physics. 1280 references, 52 figures, 76 tables.

  11. Interferometry with atoms

    International Nuclear Information System (INIS)

    Optics and interferometry with matter waves is the art of coherently manipulating the translational motion of particles like neutrons, atoms and molecules. Coherent atom optics is an extension of techniques that were developed for manipulating internal quantum states. Applying these ideas to translational motion required the development of techniques to localize atoms and transfer population coherently between distant localities. In this view position and momentum are (continuous) quantum mechanical degrees of freedom analogous to discrete internal quantum states. In our contribution we start with an introduction into matter wave optics in sect. 1, discuss coherent atom optics and atom interferometry techniques for molecular beams in sect. 2 and for trapped atoms in sect. 3. In sect. 4 we then describe tools and experiments that allow to probe the evolution of quantum states of many-body systems by atom interference.

  12. Thoughts on the new whole body counting techniques using short counting times

    International Nuclear Information System (INIS)

    The history of the beginnings of ''Whole Body Counters'' which employ short counting times is discussed as well as some of the methodology used in this work. Originally, the purpose of this type of counter was to screen people quickly; those who showed evidence of a recent increase in internal deposition would be counted on a more sensitive counter for a better definition of their body burdens, while those who showed no change were not studied further. This conservative practice was rapidly dropped by client end-users who responded to economic pressures and began to use the counter more as an ''ultimate truth'' machine. Thus, software and counting methods necessarily had to be changed to provide the end-user with equipment which could also provide both qualitative and quantitative results within the intent of ANSI Standard N343. A proposal is made which may be controversial with the legal staff, but which holds tenaciously to the principle of ALARA; provide a proper balance between internal and external dose commitments through the careful choice of the need for wearing respiratory protective equipment and its resultant decrease in the efficiency of a worker, thus potentially increasing the external exposure

  13. Somatic Cell Count, Importance and Effect Factors in Dairy Cattle

    OpenAIRE

    İbrahim Aytekin; Saim Boztepe

    2014-01-01

    The somatic cell count (SCC) is commonly used as a measure of udder health and milk quality. Thus, to determine the milk quality standards in many countries, it legally determined as an indicator of somatic cell count raw milk and determines the level of payments to milk producers. The present study investigated that the somatic cell count is an indicator of udder health status, diagnosis of subclinical mastitis, health and quality of milk and milk products, its importance and effect factors ...

  14. Three-dimensional photon counting double-random-phase encryption.

    Science.gov (United States)

    Cho, Myungjin; Javidi, Bahram

    2013-09-01

    In this Letter, we present a three-dimensional (3D) photon counting double-random-phase encryption (DRPE) technique using passive integral imaging. A 3D photon counting DRPE can encrypt a 3D scene and provides more security and authentications due to photon counting Poisson nonlinear transformation on the encrypted image. In addition, 3D imaging allows verification of the 3D object at different depths. Preliminary results and performance evaluation have been presented. PMID:23988912

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

    Science.gov (United States)

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

    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.

  16. Enumeration of islets by nuclei counting and light microscopic analysis

    OpenAIRE

    Pisania, Anna; Papas, Klearchos K.; Powers, Daryl E.; Rappel, Michael J.; Omer, Abdulkadir; Bonner-Weir, Susan; Weir, Gordon C.; Colton, Clark K.

    2010-01-01

    Islet enumeration in impure preparations by conventional dithizone staining and visual counting is inaccurate and operator dependent. We examined nuclei counting for measuring the total number of cells in islet preparations, and we combined it with morphological analysis by light microscopy (LM) for estimating the volume fraction of islets in impure preparations. Cells and islets were disrupted with lysis solution and shear, and accuracy of counting successively diluted nuclei suspensions was...

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

    Science.gov (United States)

    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.

  18. Analysis of General Power Counting Rules in Effective Field Theory

    OpenAIRE

    Gavela, B. M.; Jenkins, E. E.; Manohar, A. V.; Merlo, L.

    2016-01-01

    We derive the general counting rules for a quantum effective field theory (EFT) in $\\mathsf{d}$ dimensions. The rules are valid for strongly and weakly coupled theories, and predict that all kinetic energy terms are canonically normalized. They determine the energy dependence of scattering cross sections in the range of validity of the EFT expansion. The size of cross sections is controlled by the $\\Lambda$ power counting of EFT, not by chiral counting, even for chiral perturbation theory ($\\...

  19. A comparison of phytoplankton and total particle counts

    OpenAIRE

    Beattie, I.H.

    1981-01-01

    Phytoplankton counts made under the light microscope were compared to counts using an electronic dimensional particle counter. Counts were made on a monthly basis, on water samples taken from one station in the Sanyati Basin. Neither total particle numbers nor total particle volume compare closely with phytoplankton numbers. Total particle numbers were of the order of one and a half to two times greater than the phytoplankton numbers.

  20. Digital frequency meter using DMA Terminal Count stop method

    OpenAIRE

    Mr. B.pramod Kumar; Dr.D.V.RamaKotiReddy; Mr. N.Suresh kumar; Mr. A. Harish

    2010-01-01

    This paper presents a new wide-range speed easurement method, using the direct memory access (DMA) terminal count register(TCR). The DMAmethod is based on both pulse counting in the constant sampling time at terminal count stop pin of a DMA controller. The hardware configuration and algorithms for a microcontroller implementation are also presented. The proposed method is suitable in systems using microcontrollers with DMA controller and timers. Limitations and sources of errors are discusse...

  1. Men of physics Count Rumford on the nature of heat

    CERN Document Server

    Brown, Sanborn C

    2013-01-01

    Men of Physics: Benjamin Thompson—Count Rumford: Count Rumford on the Nature of Heat presents the life and works of Count Rumford, an American-born British physicist and inventor. This book is divided in two parts. The first part gives a biographical sketch of Count Rumford, Benjamin Thompson, who was born on March 23, 1753 and died in 1814. This part also discusses the contemporary caloric theory and the reason why Rumford disbelieved the theory. The second part presents his technical works, discoveries, and contributions in the field of physics. Some of which are his demonstration of the e

  2. Problems and precision of the alpha scintillation radon counting system

    International Nuclear Information System (INIS)

    Variations in efficiency as large as 3% have been found for radon scintillation counting systems in which the photomultiplier tubes are sensitive to the thermoluminescent photons emitted by the scintillator after exposure to light or for which the resolution has deteriorated. The additional standard deviation caused by counting a radon chamber on multiple counting systems has been evaluated and the effect, if present, did not exceed about 0.1%. The chambers have been calibrated for the measurement of radon in air, and the standard deviation was equal to statistical counting error combined with a systematic error of 1.1%. 3 references, 2 figures, 2 tables

  3. Digital frequency meter using DMA Terminal Count stop method

    Directory of Open Access Journals (Sweden)

    Mr. B.pramod Kumar

    2010-04-01

    Full Text Available This paper presents a new wide-range speed easurement method, using the direct memory access (DMA terminal count register(TCR. The DMAmethod is based on both pulse counting in the constant sampling time at terminal count stop pin of a DMA controller. The hardware configuration and algorithms for a microcontroller implementation are also presented. The proposed method is suitable in systems using microcontrollers with DMA controller and timers. Limitations and sources of errors are discussed in details. The DMA Terminal count register method is suitable for real-time speed control systems.

  4. Probing Cosmology with Weak Lensing Peak Counts

    CERN Document Server

    Kratochvil, Jan M; May, Morgan

    2009-01-01

    We propose counting peaks in weak lensing (WL) maps, as a function of their height, to probe models of dark energy and to constrain cosmological parameters. Because peaks can be identified in two-dimensional WL maps directly, they can provide constraints that are free from potential selection effects and biases involved in identifying and determining the masses of galaxy clusters. We have run cosmological N-body simulations to produce WL convergence maps in three models with different constant values of the dark energy equation of state parameter, w=-0.8, -1, and -1.2, with a fixed normalization of the primordial power spectrum (corresponding to present-day normalizations of sigma8=0.742, 0.798, and 0.839, respectively). By comparing the number of WL peaks in 8 convergence bins in the range of -0.1 < kappa < 0.2, in multiple realizations of a single simulated 3x3 degree field, we show that the first (last) pair of models can be distinguished at the 95% (85%) confidence level. A survey with depth and are...

  5. Approximating Document Frequency with Term Count Values

    CERN Document Server

    Klein, Martin

    2008-01-01

    For bounded datasets such as the TREC Web Track (WT10g) the computation of term frequency (TF) and inverse document frequency (IDF) is not difficult. However, when the corpus is the entire web, direct IDF calculation is impossible and values must instead be estimated. Most available datasets provide values for term count (TC) meaning the number of times a certain term occurs in the entire corpus. Intuitively this value is different from document frequency (DF), the number of documents (e.g., web pages) a certain term occurs in. We conduct a comparison study between TC and DF values within the Web as Corpus (WaC). We found a very strong correlation with Spearman's rho >0.8 (p<0.005) which makes us confident in claiming that for such recently created corpora the TC and DF values can be used interchangeably to compute IDF values. These results are useful for the generation of accurate lexical signatures based on the TF-IDF scheme.

  6. Weighted power counting and chiral dimensional regularization

    Science.gov (United States)

    Anselmi, Damiano

    2014-06-01

    We define a modified dimensional-regularization technique that overcomes several difficulties of the ordinary technique, and is specially designed to work efficiently in chiral and parity violating quantum field theories, in arbitrary dimensions greater than 2. When the dimension of spacetime is continued to complex values, spinors, vectors and tensors keep the components they have in the physical dimension; therefore, the γ matrices are the standard ones. Propagators are regularized with the help of evanescent higher-derivative kinetic terms, which are of the Majorana type in the case of chiral fermions. If the new terms are organized in a clever way, weighted power counting provides an efficient control on the renormalization of the theory, and allows us to show that the resulting chiral dimensional regularization is consistent to all orders. The new technique considerably simplifies the proofs of properties that hold to all orders, and makes them suitable to be generalized to wider classes of models. Typical examples are the renormalizability of chiral gauge theories and the Adler-Bardeen theorem. The difficulty of explicit computations, on the other hand, may increase.

  7. Statistical treatment of photon/electron counting; extending the linear dynamic range from the dark count rate to saturation

    OpenAIRE

    Kissick, David J.; Muir, Ryan D.; Simpson, Garth J.

    2010-01-01

    An experimentally simple photon counting method is demonstrated providing seven orders of magnitude in linear dynamic range (LDR) for a single photomultiplier tube (PMT) detector. In conventional photon/electron counting methods, the linear range is dictated by the agreement between the binomially distributed measurement of counted events and the underlying Poisson distribution of photons/electrons. By explicitly considering the lognormal probability distribution in voltage transients as a fu...

  8. Nuclear and atomic data activities in Malaysia

    International Nuclear Information System (INIS)

    Nuclear and atomic data measurements and calculations in Malaysia are mostly done at the National University of Malaysia (UKM) and Malaysian Institute for Nuclear Technology Research (MINT). At UKM, (n,t) reactions for 6Li, 10B and reactor structural materials have been investigated using liquid scintillation counting and gas phase β- anticoincidence counting. Tritium productions via ternary fission in 235U and 232Th are measured using vacuum extraction and β- counting of accumulated tritium. In addition, γ-ray attenuation coefficients on cooking oil, petroleum products, building materials, natural rubber and tropical woods have also been measured. Calculations to determine μ-value according to Hubbel method are initiated. Some collaborative works between UKM and Juelich Research Centre of Germany have been completed while others are in progress namely; (n,t) reactions study on 9Be, 10B, 14N and also measurement of excitation functions and isomer ratios of fast neutron induced reactions on Zn, Ga and Ge. At MINT, the 1-D diffusion code TRIGAM and the 2-D EXTERMINATOR code are used for neutronic analyses of TRIGA Reactor. The radiation shielding calculation have been carried out by using ANISN, a 1-D discrete ordinates code. Some preliminary calculations for the fuel transfer cask using ORIGEN2 and MERCURE-4 have been performed. Response functions for neutrons and the associated secondary photons for neutron skyshine analyses have been generated using the MCNP code. (author)

  9. Single Photon Counting UV Solar-Blind Detectors Using Silicon and III-Nitride Materials

    Directory of Open Access Journals (Sweden)

    Shouleh Nikzad

    2016-06-01

    Full Text Available Ultraviolet (UV studies in astronomy, cosmology, planetary studies, biological and medical applications often require precision detection of faint objects and in many cases require photon-counting detection. We present an overview of two approaches for achieving photon counting in the UV. The first approach involves UV enhancement of photon-counting silicon detectors, including electron multiplying charge-coupled devices and avalanche photodiodes. The approach used here employs molecular beam epitaxy for delta doping and superlattice doping for surface passivation and high UV quantum efficiency. Additional UV enhancements include antireflection (AR and solar-blind UV bandpass coatings prepared by atomic layer deposition. Quantum efficiency (QE measurements show QE > 50% in the 100–300 nm range for detectors with simple AR coatings, and QE ≅ 80% at ~206 nm has been shown when more complex AR coatings are used. The second approach is based on avalanche photodiodes in III-nitride materials with high QE and intrinsic solar blindness.

  10. Atomic collisions research with excited atomic species

    International Nuclear Information System (INIS)

    Measurements and calculations of fundamental atomic collision and spectroscopic properties such as collision cross sections, reaction rates, transition probabilities etc. underpin the understanding and operation of many plasma and gas-discharge-based devices and phenomena, for example plasma processing and deposition. In almost all cases the complex series of reactions which sustains the discharge or plasma, or produces the reactive species of interest, has a precursor electron impact excitation, attachment, dissociation or ionisation event. These processes have been extensively studied in a wide range of atomic and molecular species and an impressive data base of collision cross sections and reaction rates now exists. However, most of these measurements are for collisions with stable atomic or molecular species which are initially in their ground electronic state. Relatively little information is available for scattering from excited states or for scattering from unstable molecular radicals. Examples of such species would be metastable excited rare gases, which are often used as buffer gases, or CF2 radicals formed by electron impact dissociation in a CF4 plasma processing discharge. We are interested in developing experimental techniques which will enable the quantitative study of such exotic atomic and molecular species. In this talk I would like to outline one such facility which is being used for studies of collisions with metastable He(23S) atoms

  11. Long range intermolecular forces in triatomic systems: connecting the atom-diatom and atom-atom-atom representations

    OpenAIRE

    Cvitas, Marko T.; Soldan, Pavel; Hutson, Jeremy M.

    2005-01-01

    The long-range forces that act between three atoms are analysed in both atom-diatom and atom-atom-atom representations. Expressions for atom-diatom dispersion coefficients are obtained in terms of 3-body nonadditive coefficients. The anisotropy of atom-diatom C_6 dispersion coefficients arises primarily from nonadditive triple-dipole and quadruple-dipole forces, while pairwise-additive forces and nonadditive triple-dipole and dipole-dipole-quadrupole forces contribute significantly to atom-di...

  12. Effect of a biological activated carbon filter on particle counts

    Institute of Scientific and Technical Information of China (English)

    Su-hua WU; Bing-zhi DONG; Tie-jun QIAO; Jin-song ZHANG

    2008-01-01

    Due to the importance of biological safety in drinking water quality and the disadvantages which exist in traditional methods of detecting typical microorganisms such as Cryptosporidium and Giardia,it is necessary to develop an alternative.Particle counts is a qualitative measurement of the amount of dissolved solids in water.The removal rate of particle counts was previously used as an indicator of the effectiveness of a biological activated carbon(BAC)filter in removing Cryptosporidium and Giardia.The particle counts in a BAC filter effluent over one operational period and the effects of BAC filter construction and operational parameters were investigated with a 10 m3/h pilot plant.The results indicated that the maximum particle count in backwash remnant water was as high as 1296 count/ml and it needed about 1.5 h to reduce from the maximum to less than 50 count/ml.During the standard filtration period,particle counts stay constant at less than 50 count/ml for 5 d except when influ-enced by sand filter backwash remnant water.The removal rates of particle counts in the BAC filter are related to characteristics of the carbon.For example,a columned carbon and a sand bed removed 33.3% and 8.5% of particles,respectively,while the particle counts in effluent from a cracked BAC filter was higher than that of the influent.There is no significant difference among particle removal rates with different filtration rates.High post-ozone dosage(>2 mg/L)plays an important role in particle count removal;when the dosage was 3 mg/L,the removal rates by carbon layers and sand beds decreased by 17.5% and increased by 9.5%,respectively,compared with a 2 mg/L dosage.

  13. Low background counting of 222Rn, 220Rn and 219Rn with electrostatic counters

    Science.gov (United States)

    Mong, Brian; EXO-200 Collaboration; nEXO Collaboration

    2014-09-01

    The radon counting technique based on electrostatic precipitation of progenies in gas followed by alpha spectroscopy has been applied to support the material selection programs of low background, neutrino and dark matter experiments with emphasis on EXO. An array of 8 counters operated by Laurentian University at SNOLAB and the Waste Isolation Pilot Plant have reached the sensitivity of 10 atoms/day in the uranium, thorium and actinium chains. Hardware improvements are underway to further increase the capacity and sensitivity in support of nEXO. The radon counting technique based on electrostatic precipitation of progenies in gas followed by alpha spectroscopy has been applied to support the material selection programs of low background, neutrino and dark matter experiments with emphasis on EXO. An array of 8 counters operated by Laurentian University at SNOLAB and the Waste Isolation Pilot Plant have reached the sensitivity of 10 atoms/day in the uranium, thorium and actinium chains. Hardware improvements are underway to further increase the capacity and sensitivity in support of nEXO. Supported by NSERC Project Grants ``Search for Double Beta Decay with EXO.''

  14. Graphite filter atomizer in atomic absorption spectrometry

    Science.gov (United States)

    Katskov, Dmitri A.

    2007-09-01

    Graphite filter atomizers (GFA) for electrothermal atomic absorption spectrometry (ETAAS) show substantial advantages over commonly employed electrothermal vaporizers and atomizers, tube and platform furnaces, for direct determination of high and medium volatility elements in matrices associated with strong spectral and chemical interferences. Two factors provide lower limits of detection and shorter determination cycles with the GFA: the vaporization area in the GFA is separated from the absorption volume by a porous graphite partition; the sample is distributed over a large surface of a collector in the vaporization area. These factors convert the GFA into an efficient chemical reactor. The research concerning the GFA concept, technique and analytical methodology, carried out mainly in the author's laboratory in Russia and South Africa, is reviewed. Examples of analytical applications of the GFA in AAS for analysis of organic liquids and slurries, bio-samples and food products are given. Future prospects for the GFA are discussed in connection with analyses by fast multi-element AAS.

  15. From particle counting to Gaussian tomography

    Science.gov (United States)

    Parthasarathy, K. R.; Sengupta, Ritabrata

    2015-12-01

    The momentum and position observables in an n-mode boson Fock space Γ(ℂn) have the whole real line ℝ as their spectrum. But the total number operator N has a discrete spectrum ℤ+ = {0, 1, 2,…}. An n-mode Gaussian state in Γ(ℂn) is completely determined by the mean values of momentum and position observables and their covariance matrix which together constitute a family of n(2n + 3) real parameters. Starting with N and its unitary conjugates by the Weyl displacement operators and operators from a representation of the symplectic group Sp(2n) in Γ(ℂn), we construct n(2n + 3) observables with spectrum ℤ+ but whose expectation values in a Gaussian state determine all its mean and covariance parameters. Thus measurements of discrete-valued observables enable the tomography of the underlying Gaussian state and it can be done by using five one-mode and four two-mode Gaussian symplectic gates in single and pair mode wires of Γ(ℂn) = Γ(ℂ)⊗n. Thus the tomography protocol admits a simple description in a language similar to circuits in quantum computation theory. Such a Gaussian tomography applied to outputs of a Gaussian channel with coherent input states permit a tomography of the channel parameters. However, in our procedure the number of counting measurements exceeds the number of channel parameters slightly. Presently, it is not clear whether a more efficient method exists for reducing this tomographic complexity. As a byproduct of our approach an elementary derivation of the probability generating function of N in a Gaussian state is given. In many cases the distribution turns out to be infinitely divisible and its underlying Lévy measure can be obtained. However, we are unable to derive the exact distribution in all cases. Whether this property of infinite divisibility holds in general is left as an open problem.

  16. Atomic Power Safety

    Energy Technology Data Exchange (ETDEWEB)

    Hogerton, John F

    1964-01-01

    This booklet is condensed from a larger publication, -Background Information on Atomic Power Safety-, published in January 1964, by the .Atomic Industrial Forum. That publication and this abridgment were produced in recognition of the emergence of commercial atomic power as an important factor in our national economy, and of the resulting need for readily available information in nontechnical form on the characteristics of nuclear power plants and on the various measures taken during their design, construction, and operation for public safety.

  17. Atomic Oxygen Effects

    Science.gov (United States)

    Miller, Sharon K. R.

    2014-01-01

    Atomic oxygen, which is the most predominant species in low Earth orbit, is highly reactive and can break chemical bonds on the surface of a wide variety of materials leading to volatilization or surface oxidation which can result in failure of spacecraft materials and components. This presentation will give an overview of how atomic oxygen reacts with spacecraft materials, results of space exposure testing of a variety of materials, and examples of failures caused by atomic oxygen.

  18. Metal atom oxidation laser

    International Nuclear Information System (INIS)

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides

  19. Metal atom oxidation laser

    Science.gov (United States)

    Jensen, R.J.; Rice, W.W.; Beattie, W.H.

    1975-10-28

    A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides. (auth)

  20. Hirshfeld atom refinement

    OpenAIRE

    Capelli, Silvia C; Hans-Beat Bürgi; Birger Dittrich; Simon Grabowsky; Dylan Jayatilaka

    2014-01-01

    Hirshfeld atom refinement (HAR) is a method which determines structural parameters from single-crystal X-ray diffraction data by using an aspherical atom partitioning of tailor-made ab initio quantum mechanical molecular electron densities without any further approximation. Here the original HAR method is extended by implementing an iterative procedure of successive cycles of electron density calculations, Hirshfeld atom scattering factor calculations and structural least-squares refinements,...

  1. Advances in atomic physics

    OpenAIRE

    Tharwat M. El-Sherbini

    2015-01-01

    Graphical abstract In this review article, important developments in the field of atomic physics are highlighted and linked to research works the author was involved in himself as a leader of the Cairo University – Atomic Physics Group. Starting from the late 1960s – when the author first engaged in research - an overview is provided of the milestones in the fascinating landscape of atomic physics.

  2. Atomic and Molecular Physics

    OpenAIRE

    Cohen-Tannoudji, Claude

    2015-01-01

    When physicists began to explore the world of atoms more precisely, as they endeavoured to understand its structure and the laws governing its behaviour, they soon encountered serious difficulties. Our intuitive concepts, based on our daily experience of the macroscopic world around us, proved to be completely erroneous on the atomic scale; the atom was incomprehensible within the framework of classical physics. In order to uncover these new mysteries, after a great deal of trial and error, e...

  3. Solar Spectroscopy: Atomic Processes

    Science.gov (United States)

    Mason, H.; Murdin, P.

    2000-11-01

    A Greek philosopher called DEMOCRITUS (c. 460-370 BC) first introduced the concept of atoms (which means indivisible). His atoms do not precisely correspond to our atoms of today, which are not indivisible, but made up of a nucleus (protons with positive charge and neutrons which have no charge) and orbiting electrons (with negative charge). Indeed, in the solar atmosphere, the temperature is suc...

  4. Advances in atomic spectroscopy

    CERN Document Server

    Sneddon, J

    1997-01-01

    This series describes selected advances in the area of atomic spectroscopy. It is primarily intended for the reader who has a background in atmoic spectroscopy; suitable to the novice and expert. Although a widely used and accepted method for metal and non-metal analysis in a variety of complex samples, Advances in Atomic Spectroscopy covers a wide range of materials. Each Chapter will completely cover an area of atomic spectroscopy where rapid development has occurred.

  5. Phantom of the atom

    Energy Technology Data Exchange (ETDEWEB)

    Jones, G.

    1988-01-28

    The paper traces the radiation work of Ernest Rutherford, the founder of nuclear physics who died fifty years ago in 1937. The work on the 'plum pudding' model of the atom, the discovery of ..cap alpha.. and ..beta.. particles, disintegration theory, transmutation, model of the atom (with a small nucleus), and disintegration of the nitrogen atom using ..cap alpha.. particles, are all briefly described. (U.K.).

  6. 20 CFR 416.1104 - Income we count.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Income we count. 416.1104 Section 416.1104... DISABLED Income General § 416.1104 Income we count. We have described generally what income is and is not for SSI purposes (§ 416.1103). There are different types of income, earned and unearned, and we...

  7. Analysis of spatial count data using Kalman smoothing

    DEFF Research Database (Denmark)

    Dethlefsen, Claus

    2007-01-01

    We consider spatial count data from an agricultural field experiment. Counts of weed plants in a field have been recorded in a project on precision farming. Interest is in mapping the weed intensity so that the dose of herbicide applied at any location can be adjusted to the amount of weed presen...... combining approximate Kalman filter techniques with importance sampling....

  8. Analysis of spatial count data using Kalman smoothing

    DEFF Research Database (Denmark)

    Dethlefsen, Claus

    This paper considers spatial count data from an agricultural field experiment. Counts of weed plants in a field have been recorded in a project on precision farming. Interest is in mapping the weed intensity so that the dose of herbicide applied at any location can be adjusted to the amount of we...... combining approximate Kalman filter techniques with importance sampling....

  9. New Jersey Kids Count 2011: The State of Our Children

    Science.gov (United States)

    Advocates for Children of New Jersey, 2011

    2011-01-01

    "New Jersey Kids Count 2011" again documents both advances and setbacks in key areas that affect child well-being--poverty, health, child protection, education, including early learning, and adolescent well-being. To better gauge New Jersey's progress in essential areas, a "New Jersey Kids Count Report Card" that identifies trends in 15 key…

  10. Quantitative gamma spectroscopy at very high counting rates

    International Nuclear Information System (INIS)

    Loss-free net peak areas at variable input rates of more than 690,000 c/s have been obtained by means of a high-rate gamma spectroscopy system with real-time compensation of counting losses, thus providing evidence for the feasibility of quantitative gamma spectroscopy at counting rates not attained until now. (orig.)

  11. Counting efficiency formulae for two, three or four photomultiplier systems

    International Nuclear Information System (INIS)

    Counting efficiency formulae as a function of the non-detection probability and the electron distributions for systems with two, three or dour photomultipliers are obtained in this paper. It is assumed that the photocathode electron emission follows the Poisson distribution. The obtained formulae are basic to compute the counting efficiency in liquid scintillation spectrometers

  12. Apparatus characterization as a standard for neutron correlation counting

    International Nuclear Information System (INIS)

    Neutron correlation counting has the property that the count rate is predictable from first principles. This allows, in certain instances, replacing standards of the conventional types with a careful characterization of the apparatus. Multiplication would have to be small, and the material well characterized. An instance where circumstances forced used of such a procedure, with excellent results, is described

  13. Automated counting of white blood cells in synovial fluid.

    NARCIS (Netherlands)

    R. de Jonge (Robert); R.W. Brouwer (Reinoud); M. Smit (Marij); M. de Frankrijker-Merkestijn; R.J. Dolhain; J.M.W. Hazes (Mieke); A.W. van Toorenenbergen (Albert); J. Lindemans (Jan)

    2004-01-01

    textabstractOBJECTIVES: To evaluate the performance of automated leucocyte (white blood cell; WBC) counting by comparison with manual counting. METHODS: The number of WBC was determined in heparinized synovial fluid samples by the use of (i) a standard urine cytometer (Kova) and a

  14. Liquid scintillation counting system with automatic gain correction

    International Nuclear Information System (INIS)

    An automatic liquid scintillation counting apparatus is described including a scintillating medium in the elevator ram of the sample changing apparatus. An appropriate source of radiation, which may be the external source for standardizing samples, produces reference scintillations in the scintillating medium which may be used for correction of the gain of the counting system

  15. 34 CFR 200.91 - SEA counts of eligible children.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false SEA counts of eligible children. 200.91 Section 200.91... Prevention and Intervention Programs for Children and Youth Who are Neglected, Delinquent, or At-Risk of Dropping Out § 200.91 SEA counts of eligible children. To receive an allocation under part D, subpart 1...

  16. Important aspects of 14CO2 gas counting

    International Nuclear Information System (INIS)

    The major problems encountered when constructing a proportional counter for low background applications are discussed. They are: obtaining the low background count-rate, and the technology involved with the counter construction. In the case of CO2 counting the purification of the counter gas and the vacuum properties of the counter give additional problems

  17. Law on Atomic Energy

    International Nuclear Information System (INIS)

    The Law defines the legislative foundation and concepts for peaceful uses of atomic energy in Vietnam. The Law, including 11 chapters, 93 articles and coming into force on the 1 Jan 2009, regulates utilization of atomic energy and assurance of safety and security. The Law contains issues: general provisions; measures to promote development and application of atomic energy for peaceful purposes; radiation safety, nuclear safety and security of radioactive sources, nuclear material and facilities; exploration, exploitation and processing radioactive ores; transportation, import and export of radioactive materials and nuclear equipment; atomic energy application services; declaration and licensing; response to radiation or nuclear incidents and compensation for damage caused by these incidents. (VAEC)

  18. Atomic swelling upon compression

    OpenAIRE

    Dolmatov, V. K.; King, J L

    2012-01-01

    The hydrogen atom under the pressure of a spherical penetrable confinement potential of a decreasing radius $r_{0}$ is explored, as a case study. A novel counter-intuitive effect of atomic swelling rather than shrinking with decreasing $r_{0}$ is unraveled, when $r_{0}$ reaches, and remains smaller than, a certain critical value. Upon swelling, the size of the atom is shown to increase by an order of magnitude, or more, compared to the size of the free atom. Examples of changes of photoabsorp...

  19. Deeply bound pionic atom

    International Nuclear Information System (INIS)

    The standard method of pionic atom formation does not produce deeply bound pionic atoms. A study is made on the properties of deeply bound pionic atom states by using the standard pion-nucleus optical potential. Another study is made to estimate the cross sections of the formation of ls pionic atom states by various methods. The pion-nucleus optical potential is determined by weakly bound pionic atom states and pion nucleus scattering. Although this potential may not be valid for deeply bound pionic atoms, it should provide some hint on binding energies and level widths of deeply bound states. The width of the ls state comes out to be 0.3 MeV and is well separated from the rest. The charge dependence of the ls state is investigated. The binding energies and the widths increase linearly with Z azbove a Z of 30. The report then discusses various methods to populate deeply bound pionic atoms. In particular, 'pion exchange' reactions are proposed. (n, pπ) reaction is discussed first. The cross section is calculated by assuming the in- and out-going nucleons on-shell and the produced pion in (n1) pionic atom states. Then, (n, dπ-) cross sections are estimated. (p, 2Heπ-) reaction would have cross sections similar to the cross section of (n, dπ-) reaction. In conclusion, it seems best to do (n, p) experiment on heavy nuclei for deeply bound pionic atom. (Nogami, K.)

  20. Computed neutron coincidence counting applied to passive waste assay

    Energy Technology Data Exchange (ETDEWEB)

    Bruggeman, M.; Baeten, P.; De Boeck, W.; Carchon, R. [Nuclear Research Centre, Mol (Belgium)

    1997-11-01

    Neutron coincidence counting applied for the passive assay of fissile material is generally realised with dedicated electronic circuits. This paper presents a software based neutron coincidence counting method with data acquisition via a commercial PC-based Time Interval Analyser (TIA). The TIA is used to measure and record all time intervals between successive pulses in the pulse train up to count-rates of 2 Mpulses/s. Software modules are then used to compute the coincidence count-rates and multiplicity related data. This computed neutron coincidence counting (CNCC) offers full access to all the time information contained in the pulse train. This paper will mainly concentrate on the application and advantages of CNCC for the non-destructive assay of waste. An advanced multiplicity selective Rossi-alpha method is presented and its implementation via CNCC demonstrated. 13 refs., 4 figs., 2 tabs.

  1. The automated counting of spots for the ELISpot assay.

    Science.gov (United States)

    Hawkins, Natalie; Self, Steve; Wakefield, Jon

    2006-10-20

    An automated method for counting spot-forming units in the ELISpot assay is described that uses a statistical model fit to training data that is based on counts from one or more experts. The method adapts to variable background intensities and provides considerable flexibility with respect to what image features can be used to model expert counts. Point estimates of spot counts are produced together with intervals that reflect the degree of uncertainty in the count. Finally, the approach is completely transparent and "open source" in contrast to methods embedded in current commercial software. An illustrative application to data from a study of the reactivity of T-cells from healthy human subjects to a pool of immunodominant peptides from CMV, EBV and flu is presented. PMID:17010368

  2. Computed neutron coincidence counting applied to passive waste assay

    International Nuclear Information System (INIS)

    Neutron coincidence counting applied for the passive assay of fissile material is generally realised with dedicated electronic circuits. This paper presents a software based neutron coincidence counting method with data acquisition via a commercial PC-based Time Interval Analyser (TIA). The TIA is used to measure and record all time intervals between successive pulses in the pulse train up to count-rates of 2 Mpulses/s. Software modules are then used to compute the coincidence count-rates and multiplicity related data. This computed neutron coincidence counting (CNCC) offers full access to all the time information contained in the pulse train. This paper will mainly concentrate on the application and advantages of CNCC for the non-destructive assay of waste. An advanced multiplicity selective Rossi-alpha method is presented and its implementation via CNCC demonstrated. 13 refs., 4 figs., 2 tabs

  3. The Internal Gas Counter as a Precision Absolute Counting Device

    International Nuclear Information System (INIS)

    The internal gas counter is the most accurate device for the absolute counting of low energy radiations. Its usefulness can be extended to higher energies if the possible error effects are investigated and corrected thoroughly and the measuring conditions are properly chosen. The different sources of error in internal gas counting, e.g. field distortion by the isolators and guard tubes at the counter ends, irradiation from the ineffective end volumes into the counting volume, escape from the counting volume into the ends and walls, all kinds of sorption effects, and counting loss due to the finite energy discrimination during counting, are discussed in detail. The optimum counter design is derived from this discussion. The corrections for these error effects can be described with simple semi-empirical formulas, which depend only on a few constants which have to be determined. Measurements of T, 14C, 35S, 37A and 85Kr at counting-gas pressures of 200-750 Torr have been performed. They make it possible to determine all corrections in internal gas counting, depending on the energy and kind of the radiation and on the counting-gas pressure. This determination has.been done by using empirical extrapolation techniques as well as the derived formulas. The results make it possible to correct nearly every internal gas counting measurement of β-radiations, electrons and X-rays and to obtain final accuracies of 1%. Some examples of such measurements - the determination of the decay scheme of 85Kr, the measurement of the fluorescence yield of 37Cl and the half-life determination of 131mXe - are discussed briefly. (author)

  4. Total and Local Quadratic Indices of the Molecular Pseudograph's Atom Adjacency Matrix: Applications to the Prediction of Physical Properties of Organic Compounds

    Directory of Open Access Journals (Sweden)

    Yovani Marrero Ponce

    2003-08-01

    Full Text Available A novel topological approach for obtaining a family of new molecular descriptors is proposed. In this connection, a vector space E (molecular vector space, whose elements are organic molecules, is defined as a “direct sum“ of different ℜi spaces. In this way we can represent molecules having a total of i atoms as elements (vectors of the vector spaces ℜi (i=1, 2, 3,..., n; where n is number of atoms in the molecule. In these spaces the components of the vectors are atomic properties that characterize each kind of atom in particular. The total quadratic indices are based on the calculation of mathematical quadratic forms. These forms are functions of the k-th power of the molecular pseudograph's atom adjacency matrix (M. For simplicity, canonical bases are selected as the quadratic forms' bases. These indices were generalized to “higher analogues“ as number sequences. In addition, this paper also introduces a local approach (local invariant for molecular quadratic indices. This approach is based mainly on the use of a local matrix [Mk(G, FR]. This local matrix is obtained from the k-th power (Mk(G of the atom adjacency matrix M. Mk(G, FR includes the elements of the fragment of interest and those that are connected with it, through paths of length k. Finally, total (and local quadratic indices have been used in QSPR studies of four series of organic compounds. The quantitative models found are significant from a statistical point of view and permit a clear interpretation of the studied properties in terms of the structural features of molecules. External prediction series and cross-validation procedures (leave-one-out and leave-group-out assessed model predictability. The reported method has shown similar results, compared with other topological approaches. The results obtained were the following: a Seven physical properties of 74 normal and branched alkanes (boiling points

  5. Evanescent Wave Atomic Mirror

    Science.gov (United States)

    Ghezali, S.; Taleb, A.

    2008-09-01

    A research project at the "Laboratoire d'électronique quantique" consists in a theoretical study of the reflection and diffraction phenomena via an atomic mirror. This poster presents the principle of an atomic mirror. Many groups in the world have constructed this type of atom optics experiments such as in Paris-Orsay-Villetaneuse (France), Stanford-Gaithersburg (USA), Munich-Heidelberg (Germany), etc. A laser beam goes into a prism with an incidence bigger than the critical incidence. It undergoes a total reflection on the plane face of the prism and then exits. The transmitted resulting wave out of the prism is evanescent and repulsive as the frequency detuning of the laser beam compared to the atomic transition δ = ωL-ω0 is positive. The cold atomic sample interacts with this evanescent wave and undergoes one or more elastic bounces by passing into backward points in its trajectory because the atoms' kinetic energy (of the order of the μeV) is less than the maximum of the dipolar potential barrier ℏΩ2/Δ where Ω is the Rabi frequency [1]. In fact, the atoms are cooled and captured in a magneto-optical trap placed at a distance of the order of the cm above the prism surface. The dipolar potential with which interact the slow atoms is obtained for a two level atom in a case of a dipolar electric transition (D2 Rubidium transition at a wavelength of 780nm delivered by a Titane-Saphir laser between a fundamental state Jf = l/2 and an excited state Je = 3/2). This potential is corrected by an attractive Van der Waals term which varies as 1/z3 in the Lennard-Jones approximation (typical atomic distance of the order of λ0/2π where λ0 is the laser wavelength) and in 1/z4 if the distance between the atom and its image in the dielectric is big in front of λ0/2π. This last case is obtained in a quantum electrodynamic calculation by taking into account an orthornormal base [2]. We'll examine the role of spontaneous emission for which the rate is inversely

  6. Do Not Divide Count Data with Count Data; A Story from Pollination Ecology with Implications Beyond.

    Science.gov (United States)

    Reitan, Trond; Nielsen, Anders

    2016-01-01

    Studies in ecology are often describing observed variations in a certain ecological phenomenon by use of environmental explanatory variables. A common problem is that the numerical nature of the ecological phenomenon does not always fit the assumptions underlying traditional statistical tests. A text book example comes from pollination ecology where flower visits are normally reported as frequencies; number of visits per flower per unit time. Using visitation frequencies in statistical analyses comes with two major caveats: the lack of knowledge on its error distribution and that it does not include all information found in the data; 10 flower visits in 20 flowers is treated the same as recording 100 visits in 200 flowers. We simulated datasets with various "flower visitation distributions" over various numbers of flowers observed (exposure) and with different types of effects inducing variation in the data. The different datasets were then analyzed first with the traditional approach using number of visits per flower and then by using count data models. The analysis of count data gave a much better chance of detecting effects than the traditionally used frequency approach. We conclude that if the data structure, statistical analyses and interpretations of results are mixed up, valuable information can be lost. PMID:26872136

  7. Zeeman atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    A new method of background correction in atomic absorption spectroscopy has recently been introduced, based on the Zeeman splitting of spectral lines in a magnetic field. A theoretical analysis of the background correction capability observed in such instruments is presented. A Zeeman atomic absorption spectrometer utilizing a 50 Hz sine wave modulated magnetic field is described. (Auth.)

  8. When Atoms Want

    Science.gov (United States)

    Talanquer, Vicente

    2013-01-01

    Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use…

  9. Spectroscopic atom symbolism

    International Nuclear Information System (INIS)

    Quantum numbers are introduced of the individual electrons of a multi-electron atom as are the concepts of electron configuration and configuration state diagram. An atom is described in Russell-Saunders approximation using the vector model concept. Overall quantum numbers are introduced for the electron shell and their relationships are discussed to the quantum numbers of the individual shell electrons. (author)

  10. Atoms, Molecules, and Compounds

    CERN Document Server

    Manning, Phillip

    2007-01-01

    Explores the atoms that govern chemical processes. This book shows how the interactions between simple substances such as salt and water are crucial to life on Earth and how those interactions are predestined by the atoms that make up the molecules.

  11. Multiphoton ionization of atoms

    International Nuclear Information System (INIS)

    The paper is devoted to the analysis of high intensity effects which result from multiphoton ionization of atoms in a high laser intensity, ranging from 1010 to 1015 W cm-2. Resonant multiphoton ionization of atoms, the production of multiply charged ions, and electron energy spectra, are all discussed. (U.K.)

  12. Greek Atomic Theory.

    Science.gov (United States)

    Roller, Duane H. D.

    1981-01-01

    Focusing on history of physics, which began about 600 B.C. with the Ionian Greeks and reaching full development within three centuries, suggests that the creation of the concept of the atom is understandable within the context of Greek physical theory; so is the rejection of the atomic theory by the Greek physicists. (Author/SK)

  13. Atomic Scale Plasmonic Switch.

    Science.gov (United States)

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Pedersen, Andreas; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2016-01-13

    The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level. PMID:26670551

  14. Atomic Energy Control Board

    International Nuclear Information System (INIS)

    This paper has been prepared to provide an overview of the responsibilities and activities of the Atomic Energy Control Board. It is designed to address questions that are often asked concerning the establishment of the Atomic Energy Control Board, its enabling legislation, licensing and compliance activities, federal-provincial relationships, international obligations, and communications with the public

  15. Dark-count-less photon-counting x-ray computed tomography system using a YAP-MPPC detector

    Science.gov (United States)

    Sato, Eiichi; Sato, Yuich; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

    2012-10-01

    A high-sensitive X-ray computed tomography (CT) system is useful for decreasing absorbed dose for patients, and a dark-count-less photon-counting CT system was developed. X-ray photons are detected using a YAP(Ce) [cerium-doped yttrium aluminum perovskite] single crystal scintillator and an MPPC (multipixel photon counter). Photocurrents are amplified by a high-speed current-voltage amplifier, and smooth event pulses from an integrator are sent to a high-speed comparator. Then, logical pulses are produced from the comparator and are counted by a counter card. Tomography is accomplished by repeated linear scans and rotations of an object, and projection curves of the object are obtained by the linear scan. The image contrast of gadolinium medium slightly fell with increase in lower-level voltage (Vl) of the comparator. The dark count rate was 0 cps, and the count rate for the CT was approximately 250 kcps.

  16. In-trap fluorescence detection of atoms in a microscopic dipole trap

    CERN Document Server

    Hilliard, A J; Sompet, P; Carpentier, A V; Andersen, M F

    2015-01-01

    We investigate fluorescence detection using a standing wave of blue-detuned light of one or more atoms held in a deep, microscopic dipole trap. The blue-detuned standing wave realizes a Sisyphus laser cooling mechanism so that an atom can scatter many photons while remaining trapped. When imaging more than one atom, the blue detuning limits loss due to inelastic light-assisted collisions. Using this standing wave probe beam, we demonstrate that we can count from one to the order of 100 atoms in the microtrap with sub-poissonian precision.

  17. Antiprotonic-hydrogen atoms

    International Nuclear Information System (INIS)

    Experimental studies of antiprotonic-hydrogen atoms have recently made great progress following the commissioning of the low energy antiproton facility (LEAR) at CERN in 1983. At the same time our understanding of the atomic cascade has increased considerably through measurements of the X-ray spectra. The life history of the p-bar-p atom is considered in some detail, from the initial capture of the antiproton when stopping in hydrogen, through the atomic cascade with the emission of X-rays, to the final antiproton annihilation and production of mesons. The experiments carried out at LEAR are described and the results compared with atomic cascade calculations and predictions of strong interaction effects. (author)

  18. Atomic diffusion in stars

    CERN Document Server

    Michaud, Georges; Richer, Jacques

    2015-01-01

    This book gives an overview of atomic diffusion, a fundamental physical process, as applied to all types of stars, from the main sequence to neutron stars. The superficial abundances of stars as well as their evolution can be significantly affected. The authors show where atomic diffusion plays an essential role and how it can be implemented in modelling.  In Part I, the authors describe the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. One of the goals of this book is to provide the means for the astrophysicist or graduate student to evaluate the importanc...

  19. Moving Single Atoms

    Science.gov (United States)

    Stuart, Dustin

    2016-05-01

    Single neutral atoms are promising candidates for qubits, the fundamental unit of quantum information. We have built a set of optical tweezers for trapping and moving single Rubidium atoms. The tweezers are based on a far off-resonant dipole trapping laser focussed to a 1 μm spot with a single aspheric lens. We use a digital micromirror device (DMD) to generate dynamic holograms of the desired arrangement of traps. The DMD has a frame rate of 20 kHz which, when combined with fast algorithms, allows for rapid reconfiguration of the traps. We demonstrate trapping of up to 20 atoms in arbitrary arrangements, and the transport of a single-atom over a distance of 14 μm with continuous laser cooling, and 5 μm without. In the meantime, we are developing high-finesse fibre-tip cavities, which we plan to use to couple pairs of single atoms to form a quantum network.

  20. The piecewise-linear dynamic attenuator reduces the impact of count rate loss with photon-counting detectors

    International Nuclear Information System (INIS)

    Photon counting x-ray detectors (PCXDs) offer several advantages compared to standard energy-integrating x-ray detectors, but also face significant challenges. One key challenge is the high count rates required in CT. At high count rates, PCXDs exhibit count rate loss and show reduced detective quantum efficiency in signal-rich (or high flux) measurements. In order to reduce count rate requirements, a dynamic beam-shaping filter can be used to redistribute flux incident on the patient. We study the piecewise-linear attenuator in conjunction with PCXDs without energy discrimination capabilities. We examined three detector models: the classic nonparalyzable and paralyzable detector models, and a ‘hybrid’ detector model which is a weighted average of the two which approximates an existing, real detector (Taguchi et al 2011 Med. Phys. 38 1089–102 ). We derive analytic expressions for the variance of the CT measurements for these detectors. These expressions are used with raw data estimated from DICOM image files of an abdomen and a thorax to estimate variance in reconstructed images for both the dynamic attenuator and a static beam-shaping (‘bowtie’) filter. By redistributing flux, the dynamic attenuator reduces dose by 40% without increasing peak variance for the ideal detector. For non-ideal PCXDs, the impact of count rate loss is also reduced. The nonparalyzable detector shows little impact from count rate loss, but with the paralyzable model, count rate loss leads to noise streaks that can be controlled with the dynamic attenuator. With the hybrid model, the characteristic count rates required before noise streaks dominate the reconstruction are reduced by a factor of 2 to 3. We conclude that the piecewise-linear attenuator can reduce the count rate requirements of the PCXD in addition to improving dose efficiency. The magnitude of this reduction depends on the detector, with paralyzable detectors showing much greater benefit than nonparalyzable

  1. The piecewise-linear dynamic attenuator reduces the impact of count rate loss with photon-counting detectors

    Science.gov (United States)

    Hsieh, Scott S.; Pelc, Norbert J.

    2014-06-01

    Photon counting x-ray detectors (PCXDs) offer several advantages compared to standard energy-integrating x-ray detectors, but also face significant challenges. One key challenge is the high count rates required in CT. At high count rates, PCXDs exhibit count rate loss and show reduced detective quantum efficiency in signal-rich (or high flux) measurements. In order to reduce count rate requirements, a dynamic beam-shaping filter can be used to redistribute flux incident on the patient. We study the piecewise-linear attenuator in conjunction with PCXDs without energy discrimination capabilities. We examined three detector models: the classic nonparalyzable and paralyzable detector models, and a ‘hybrid’ detector model which is a weighted average of the two which approximates an existing, real detector (Taguchi et al 2011 Med. Phys. 38 1089-102 ). We derive analytic expressions for the variance of the CT measurements for these detectors. These expressions are used with raw data estimated from DICOM image files of an abdomen and a thorax to estimate variance in reconstructed images for both the dynamic attenuator and a static beam-shaping (‘bowtie’) filter. By redistributing flux, the dynamic attenuator reduces dose by 40% without increasing peak variance for the ideal detector. For non-ideal PCXDs, the impact of count rate loss is also reduced. The nonparalyzable detector shows little impact from count rate loss, but with the paralyzable model, count rate loss leads to noise streaks that can be controlled with the dynamic attenuator. With the hybrid model, the characteristic count rates required before noise streaks dominate the reconstruction are reduced by a factor of 2 to 3. We conclude that the piecewise-linear attenuator can reduce the count rate requirements of the PCXD in addition to improving dose efficiency. The magnitude of this reduction depends on the detector, with paralyzable detectors showing much greater benefit than nonparalyzable detectors.

  2. The piecewise-linear dynamic attenuator reduces the impact of count rate loss with photon-counting detectors.

    Science.gov (United States)

    Hsieh, Scott S; Pelc, Norbert J

    2014-06-01

    Photon counting x-ray detectors (PCXDs) offer several advantages compared to standard energy-integrating x-ray detectors, but also face significant challenges. One key challenge is the high count rates required in CT. At high count rates, PCXDs exhibit count rate loss and show reduced detective quantum efficiency in signal-rich (or high flux) measurements. In order to reduce count rate requirements, a dynamic beam-shaping filter can be used to redistribute flux incident on the patient. We study the piecewise-linear attenuator in conjunction with PCXDs without energy discrimination capabilities. We examined three detector models: the classic nonparalyzable and paralyzable detector models, and a 'hybrid' detector model which is a weighted average of the two which approximates an existing, real detector (Taguchi et al 2011 Med. Phys. 38 1089-102). We derive analytic expressions for the variance of the CT measurements for these detectors. These expressions are used with raw data estimated from DICOM image files of an abdomen and a thorax to estimate variance in reconstructed images for both the dynamic attenuator and a static beam-shaping ('bowtie') filter. By redistributing flux, the dynamic attenuator reduces dose by 40% without increasing peak variance for the ideal detector. For non-ideal PCXDs, the impact of count rate loss is also reduced. The nonparalyzable detector shows little impact from count rate loss, but with the paralyzable model, count rate loss leads to noise streaks that can be controlled with the dynamic attenuator. With the hybrid model, the characteristic count rates required before noise streaks dominate the reconstruction are reduced by a factor of 2 to 3. We conclude that the piecewise-linear attenuator can reduce the count rate requirements of the PCXD in addition to improving dose efficiency. The magnitude of this reduction depends on the detector, with paralyzable detectors showing much greater benefit than nonparalyzable detectors. PMID

  3. Modelling of fire count data: fire disaster risk in Ghana.

    Science.gov (United States)

    Boadi, Caleb; Harvey, Simon K; Gyeke-Dako, Agyapomaa

    2015-01-01

    Stochastic dynamics involved in ecological count data require distribution fitting procedures to model and make informed judgments. The study provides empirical research, focused on the provision of an early warning system and a spatial graph that can detect societal fire risks. It offers an opportunity for communities, organizations, risk managers, actuaries and governments to be aware of, and understand fire risks, so that they will increase the direct tackling of the threats posed by fire. Statistical distribution fitting method that best helps identify the stochastic dynamics of fire count data is used. The aim is to provide a fire-prediction model and fire spatial graph for observed fire count data. An empirical probability distribution model is fitted to the fire count data and compared to the theoretical probability distribution of the stochastic process of fire count data. The distribution fitted to the fire frequency count data helps identify the class of models that are exhibited by the fire and provides time leading decisions. The research suggests that fire frequency and loss (fire fatalities) count data in Ghana are best modelled with a Negative Binomial Distribution. The spatial map of observed fire frequency and fatality measured over 5 years (2007-2011) offers in this study a first regional assessment of fire frequency and fire fatality in Ghana. PMID:26702383

  4. Study on advancement of in vivo counting using mathematical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kinase, Sakae [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-05-01

    To obtain an assessment of the committed effective dose, individual monitoring for the estimation of intakes of radionuclides is required. For individual monitoring of exposure to intakes of radionuclides, direct measurement of radionuclides in the body - in vivo counting- is very useful. To advance in a precision in vivo counting which fulfills the requirements of ICRP 1990 recommendations, some problems, such as the investigation of uncertainties in estimates of body burdens by in vivo counting, and the selection of the way to improve the precision, have been studied. In the present study, a calibration technique for in vivo counting application using Monte Carlo simulation was developed. The advantage of the technique is that counting efficiency can be obtained for various shapes and sizes that are very difficult to change for phantoms. To validate the calibration technique, the response functions and counting efficiencies of a whole-body counter installed in JAERI were evaluated using the simulation and measurements. Consequently, the calculations are in good agreement with the measurements. The method for the determination of counting efficiency curves as a function of energy was developed using the present technique and a physiques correction equation was derived from the relationship between parameters of correction factor and counting efficiencies of the JAERI whole-body counter. The uncertainties in body burdens of {sup 137}Cs estimated with the JAERI whole-body counter were also investigated using the Monte Carlo simulation and measurements. It was found that the uncertainties of body burdens estimated with the whole-body counter are strongly dependent on various sources of uncertainty such as radioactivity distribution within the body and counting statistics. Furthermore, the evaluation method of the peak efficiencies of a Ge semi-conductor detector was developed by Monte Carlo simulation for optimum arrangement of Ge semi-conductor detectors for

  5. Study on advancement of in vivo counting using mathematical simulation

    International Nuclear Information System (INIS)

    To obtain an assessment of the committed effective dose, individual monitoring for the estimation of intakes of radionuclides is required. For individual monitoring of exposure to intakes of radionuclides, direct measurement of radionuclides in the body - in vivo counting- is very useful. To advance in a precision in vivo counting which fulfills the requirements of ICRP 1990 recommendations, some problems, such as the investigation of uncertainties in estimates of body burdens by in vivo counting, and the selection of the way to improve the precision, have been studied. In the present study, a calibration technique for in vivo counting application using Monte Carlo simulation was developed. The advantage of the technique is that counting efficiency can be obtained for various shapes and sizes that are very difficult to change for phantoms. To validate the calibration technique, the response functions and counting efficiencies of a whole-body counter installed in JAERI were evaluated using the simulation and measurements. Consequently, the calculations are in good agreement with the measurements. The method for the determination of counting efficiency curves as a function of energy was developed using the present technique and a physiques correction equation was derived from the relationship between parameters of correction factor and counting efficiencies of the JAERI whole-body counter. The uncertainties in body burdens of 137Cs estimated with the JAERI whole-body counter were also investigated using the Monte Carlo simulation and measurements. It was found that the uncertainties of body burdens estimated with the whole-body counter are strongly dependent on various sources of uncertainty such as radioactivity distribution within the body and counting statistics. Furthermore, the evaluation method of the peak efficiencies of a Ge semi-conductor detector was developed by Monte Carlo simulation for optimum arrangement of Ge semi-conductor detectors for designing a

  6. High nevus counts confer a favorable prognosis in melanoma patients

    OpenAIRE

    Ribero, Simone; Davies, John R; Requena, Celia; Carrera, Cristina; Glass, Daniel; Rull, Ramon; Vidal-Sicart, Sergi; Vilalta, Antonio; Alos, Lucia; Soriano, Virtudes; Quaglino, Pietro; Traves, Victor; Newton-Bishop, Julia A; Nagore, Eduardo; Malvehy, Josep

    2015-01-01

    A high number of nevi is the most significant phenotypic risk factor for melanoma and is in part genetically determined. The number of nevi decreases from middle age onward but this senescence can be delayed in patients with melanoma. We investigated the effects of nevus number count on sentinel node status and melanoma survival in a large cohort of melanoma cases. Out of 2,184 melanoma cases, 684 (31.3%) had a high nevus count (>50). High nevus counts were associated with favorable progno...

  7. A Novel Method for Ion Track Counting in Polycarbonate Detector

    Directory of Open Access Journals (Sweden)

    Gholam Hossein Roshani

    2013-01-01

    Full Text Available A computer program for recognizing and counting the track of ions that are detected with polycarbonate detector has been written using MATLAB software. There are different programs for counting the track of ions in different detectors. Algorithm of this program specially has been written for polycarbonate detector and also for low magnification of optical microscope. Thus, with this method as per image of optical microscope, greater numbers of ions are visible and general distribution of ions can be better known. However, the accuracy of counting program is very high.

  8. Scheme dependence of instanton counting in ALE spaces

    CERN Document Server

    Ito, Yuto; Okuda, Takuya

    2013-01-01

    There have been two distinct schemes studied in the literature for instanton counting in A_{p-1} asymptotically locally Euclidean (ALE) spaces. We point out that the two schemes---namely the counting of orbifolded instantons and instanton counting in the resolved space---lead in general to different results for partition functions. We illustrate this observation in the case of N=2 U(N) gauge theory with 2N flavors on the A_{p-1} ALE space. We propose simple relations between the instanton partition functions given by the two schemes and test them by explicit calculations.

  9. Galaxy number counts to second order and their bispectrum

    CERN Document Server

    Di Dio, Enea; Marozzi, Giovanni; Montanari, Francesco

    2014-01-01

    We determine the number counts to second order in cosmological perturbation theory in the Poisson gauge and allowing for anisotropic stress. The calculation is performed using an innovative approach based on the recently proposed "geodesic light-cone" gauge. This allows us to determine the number counts in a purely geometric way, without using Einstein's equation. The result is valid for general dark energy models and (most) modified gravity models. We then evaluate numerically the relevant contributions to the number counts bispectrum. In particular we consider the terms involving the density, redshift space distortion and lensing.

  10. Galaxy number counts to second order and their bispectrum

    Energy Technology Data Exchange (ETDEWEB)

    Dio, Enea Di; Durrer, Ruth; Marozzi, Giovanni; Montanari, Francesco, E-mail: Enea.DiDio@unige.ch, E-mail: Ruth.Durrer@unige.ch, E-mail: Giovanni.Marozzi@unige.ch, E-mail: Francesco.Montanari@unige.ch [Université de Genève, Département de Physique Théorique and CAP, 24 quai Ernest-Ansermet, CH-1211 Genève 4 (Switzerland)

    2014-12-01

    We determine the number counts to second order in cosmological perturbation theory in the Poisson gauge and allowing for anisotropic stress. The calculation is performed using an innovative approach based on the recently proposed ''geodesic light-cone'' gauge. This allows us to determine the number counts in a purely geometric way, without using Einstein's equation. The result is valid for general dark energy models and (most) modified gravity models. We then evaluate numerically some relevant contributions to the number counts bispectrum. In particular we consider the terms involving the density, redshift space distortion and lensing.

  11. Fast sequential Monte Carlo methods for counting and optimization

    CERN Document Server

    Rubinstein, Reuven Y; Vaisman, Radislav

    2013-01-01

    A comprehensive account of the theory and application of Monte Carlo methods Based on years of research in efficient Monte Carlo methods for estimation of rare-event probabilities, counting problems, and combinatorial optimization, Fast Sequential Monte Carlo Methods for Counting and Optimization is a complete illustration of fast sequential Monte Carlo techniques. The book provides an accessible overview of current work in the field of Monte Carlo methods, specifically sequential Monte Carlo techniques, for solving abstract counting and optimization problems. Written by authorities in the

  12. Heterotrophic plate count methodology in the United States.

    Science.gov (United States)

    Reasoner, Donald J

    2004-05-01

    In the United States (US), the history of bacterial plate counting (BPC) methods used for water can be traced largely through Standard Methods for the Examination of Water and Wastewater (Standard Methods). The bacterial count method has evolved from the original Standard Methods (1st edition, 1905) plate count which used nutrient gelatin and incubation at 20 degrees C for 48 h, to the HPC method options in the latest edition of Standard Methods that provide greater flexibility of application, depending on the data needs of the water analyst. The use of agar-agar as a gelling agent, replacing gelatin, allowed the use of higher incubation temperatures and resulted in the "body temperature count" (37 degrees C) found in the 3rd through the 8th edition of Standard Methods. The change from 37 degrees C incubation to 35+/-0.5 degrees C accommodated laboratories that did both milk and water analyses. By using a single temperature, fewer incubators were needed. The term "standard plate count" (SPC) first appeared in 1960 (11th edition) along with plate count agar. Incubation at 20 degrees C for the plate count was dropped from the 13th to 15th editions and few changes were made in the SPC method from the 11th edition through the 13th editions. Plate count analysis of bottled waters was included in the 14th edition (1975), calling for incubation at 35+/-0.5 degrees C for 72+/-4 h. Perhaps the most significant changes in plate count methods occurred with the 16th edition (1985). The term heterotrophic plate count replaced the standard plate count, and the spread plate (SP) and membrane filter (MF) methods were added along with new media for pour and spread plates (R2A agar and NWRI agar, both low nutrient) and for the membrane filter method (mHPC medium). The use of low nutrient media, lower incubation temperature, and longer incubation times, results in higher plate count results for most water samples. The options currently available, including low and high nutrient media

  13. Exponential Time Complexity of Weighted Counting of Independent Sets

    OpenAIRE

    Hoffmann, Christian

    2010-01-01

    We consider weighted counting of independent sets using a rational weight x: Given a graph with n vertices, count its independent sets such that each set of size k contributes x^k. This is equivalent to computation of the partition function of the lattice gas with hard-core self-repulsion and hard-core pair interaction. We show the following conditional lower bounds: If counting the satisfying assignments of a 3-CNF formula in n variables (#3SAT) needs time 2^{\\Omega(n)} (i.e. there is a c>0 ...

  14. Beam test results of high counting rate MRPCs at GSI

    International Nuclear Information System (INIS)

    The usage of electrodes made of semi-conductive glass is an inspiring way of improving the counting rate capability of resistive plate chamber. We developed 6 and 10-gap multi-gap resistive plate chambers (MRPCs) with low resistive silicate glass electrodes (bulk resistivity ∼1010 Ωcm) for applications in time-of-flight (TOF) at high counting rates. These two prototypes were tested with secondary irradiation from 2.5 GeV proton beam at GSI. Time resolutions below 90 ps and efficiencies above 90% were obtained at counting rates up to 28 kHz/cm2 for the 10-gap MRPC.

  15. Terrain dependant hop count selection for transparent relay transmissions

    Directory of Open Access Journals (Sweden)

    Cibile K. Kanjirathumkal

    2013-12-01

    Full Text Available In this Letter, the selection of the best hop count for a particular topography, in the context of enhanced connectivity using multi-hop transparent relay communication is addressed. Based on the coefficient of variation and the terrain specific fading severity factor of the distribution, it is possible to estimate the optimal hop count that can provide the required performance at detector. Two distribution models, which can adequately characterise the terrain fading effects on empirical data are considered for performance comparison. The results are useful in selecting branches, with low variability and optimal hop count for connectivity, in multi-stream switched diversity combining systems.

  16. Daily variability of strongyle fecal egg counts in horses

    DEFF Research Database (Denmark)

    Carstensen, Helena; Larsen, Lene; Ritz, Christian;

    2013-01-01

    Strongyle parasites are ubiquitous in grazing horses and constitute a potential threat to equine health. Feces were collected from six horses four times daily over a period of 5 days. Fecal egg counts (FECs) were performed to identify any diurnal rhythms in strongyle egg shedding and to quantify...... variability at the different levels: individual horses, repeated counts, repeated subsamples, different time points, and different days. No significant differences in FECs were found between the different time points (P = .11). The variables-horse, day, subsample, and egg count-accounted for a variance of 104...

  17. Particle and Photon Detection: Counting and Energy Measurement.

    Science.gov (United States)

    Janesick, James; Tower, John

    2016-01-01

    Fundamental limits for photon counting and photon energy measurement are reviewed for CCD and CMOS imagers. The challenges to extend photon counting into the visible/nIR wavelengths and achieve energy measurement in the UV with specific read noise requirements are discussed. Pixel flicker and random telegraph noise sources are highlighted along with various methods used in reducing their contribution on the sensor's read noise floor. Practical requirements for quantum efficiency, charge collection efficiency, and charge transfer efficiency that interfere with photon counting performance are discussed. Lastly we will review current efforts in reducing flicker noise head-on, in hopes to drive read noise substantially below 1 carrier rms. PMID:27187398

  18. External guard counters for low-level counting systems

    International Nuclear Information System (INIS)

    The high background reduction that has been obtained with a low-level Ge-crystal counting system with external, rather than internal, guard counters is analyzed. It is shown that this arrangement eliminates not only the muon component of the cosmic rays, but also a large part of the secondary gamma radiation it produces in the passive shield and therefore gives a much higher background reduction than the conventional arrangement with the guard system inside the main passive shield. The implication of this result for low-level counting is discussed with special reference to gas proportional counting systems used for radiocarbon dating. (orig.)

  19. Detection of single atoms in particle tracks

    International Nuclear Information System (INIS)

    The one-atom detection technique was used to search for atoms which are created from the neutralization of heavy ions as they lose their energy in a gas. When 252Cf decays by binary fission, Cs/super n+/ ions are formed approximately 14% of the time (in the heavy mass peak). Thus, these ions were injected into a gas at a low rate such that the Cs neutral atom could be searched for individually and at a known time after its production. A delay of a few microseconds allowed time for collection of the 3 x 106 electrons created by the 80-MeV Cs/sup n+/ energy; then a pulsed laser was fired along each particle track to remove one electron from each Cs atom by the saturated two-step resonance ionization process. These electrons were then drifted into a gas proportional counter and detected individually to measure the probability that a neutral Cs atom would be found at the end of the fission particle track. The results show that a Cs neutral species is formed about 14% of the time, and thus nearly all Cs/sup n+/ ions become Cs0 when the ions are thermalized in P-10 (90% Ar plus 10% CH4) counting gas. Extensions of the technique to obtain other details of particle track structure are discussed. For example, it is possible to detect even one negative ion created in a track where nearly 100 MeV of energy is absorbed; it is likewise possible to determine the population of quantum-selected excited states left in the wake of these tracks. 4 figures

  20. High Speed Large Format Photon Counting Microchannel Plate Imaging Sensors

    Science.gov (United States)

    Siegmund, O.; Ertley, C.; Vallerga, J.

    The development of a new class of microchannel plate technology, using atomic layer deposition (ALD) techniques applied to a borosilicate microcapillary array is enabling the implementation of larger, more stable detectors for Astronomy and remote sensing. Sealed tubes with MCPs with SuperGenII, bialkali, GaAs and GaN photocathodes have been developed to cover a wide range of optical/UV sensing applications. Formats of 18mm and 25mm circular, and 50mm (Planacon) and 20cm square have been constructed for uses from night time remote reconnaissance and biological single-molecule fluorescence lifetime imaging microscopy, to large area focal plane imagers for Astronomy, neutron detection and ring imaging Cherenkov detection. The large focal plane areas were previously unattainable, but the new developments in construction of ALD microchannel plates allow implementation of formats of 20cm or more. Continuing developments in ALD microchannel plates offer improved overall sealed tube lifetime and gain stability, and furthermore show reduced levels of radiation induced background. High time resolution astronomical and remote sensing applications can be addressed with microchannel plate based imaging, photon time tagging detector sealed tube schemes. Photon counting imaging readouts for these devices vary from cross strip (XS), cross delay line (XDL), to stripline anodes, and pad arrays depending on the intended application. The XS and XDL readouts have been implemented in formats from 22mm, and 50mm to 20cm. Both use MCP charge signals detected on two orthogonal layers of conductive fingers to encode event X-Y positions. XDL readout uses signal propagation delay to encode positions while XS readout uses charge cloud centroiding. Spatial resolution readout of XS detectors can be better than 20 microns FWHM, with good image linearity while using low gain (5 MHz and event timing accuracy of ~100ps. We will discuss how we are applying these detector system developments for

  1. Atomic Structure Theory Lectures on Atomic Physics

    CERN Document Server

    Johnson, Walter R

    2007-01-01

    Atomic Structure Theory is a textbook for students with a background in quantum mechanics. The text is designed to give hands-on experience with atomic structure calculations. Material covered includes angular momentum methods, the central field Schrödinger and Dirac equations, Hartree-Fock and Dirac-Hartree-Fock equations, multiplet structure, hyperfine structure, the isotope shift, dipole and multipole transitions, basic many-body perturbation theory, configuration interaction, and correlation corrections to matrix elements. Numerical methods for solving the Schrödinger and Dirac eigenvalue problems and the (Dirac)-Hartree-Fock equations are given as well. B-spline basis sets are used to carry out sums arising in higher-order many-body calculations. Illustrative problems are provided, together with solutions. FORTRAN programs implementing the numerical methods in the text are included.

  2. Linear atomic quantum coupler

    CERN Document Server

    El-Orany, Faisal A A

    2009-01-01

    In this paper, we develop the notion of the linear atomic quantum coupler. This device consists of two modes propagating into two waveguides, each of them includes a localized and/or a trapped atom. These waveguides are placed close enough to allow exchanging energy between them via evanescent waves. Each mode interacts with the atom in the same waveguide in the standard way, i.e. as the Jaynes-Cummings model (JCM), and with the atom-mode in the second waveguide via evanescent wave. We present the Hamiltonian for the system and deduce the exact form for the wavefunction. We investigate the atomic inversions and the second-order correlation function. In contrast to the conventional linear coupler, the atomic quantum coupler is able to generate nonclassical effects. The atomic inversions can exhibit long revival-collapse phenomenon as well as subsidiary revivals based on the competition among the switching mechanisms in the system. Finally, under certain conditions, the system can yield the results of the two-m...

  3. Atomic Dark Matter

    OpenAIRE

    Kaplan, David E.; Krnjaic, Gordan Z.; Rehermann, Keith R.; Wells, Christopher M.

    2009-01-01

    We propose that dark matter is dominantly comprised of atomic bound states. We build a simple model and map the parameter space that results in the early universe formation of hydrogen-like dark atoms. We find that atomic dark matter has interesting implications for cosmology as well as direct detection: Protohalo formation can be suppressed below $M_{proto} \\sim 10^3 - 10^6 M_{\\odot}$ for weak scale dark matter due to Ion-Radiation interactions in the dark sector. Moreover, weak-scale dark a...

  4. EINSTEIN, SCHROEDINGER, AND ATOM

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2014-03-01

    Full Text Available In this paper, we consider gravitation theory in multidimensional space. The model of the metric satisfying the basic requirements of quantum theory is proposed. It is shown that gravitational waves are described by the Liouville equation and the Schrodinger equation as well. The solutions of the Einstein equations describing the stationary states of arbitrary quantum and classical systems with central symmetry have been obtained. Einstein’s atom model has been developed, and proved that atoms and atomic nuclei can be represented as standing gravitational waves

  5. Single-atom nanoelectronics

    CERN Document Server

    Prati, Enrico

    2013-01-01

    Single-Atom Nanoelectronics covers the fabrication of single-atom devices and related technology, as well as the relevant electronic equipment and the intriguing new phenomena related to single-atom and single-electron effects in quantum devices. It also covers the alternative approaches related to both silicon- and carbon-based technologies, also from the point of view of large-scale industrial production. The publication provides a comprehensive picture of the state of the art at the cutting edge and constitutes a milestone in the emerging field of beyond-CMOS technology. Although there are

  6. Division of atomic physics

    International Nuclear Information System (INIS)

    The Division of Atomic Physics, Lund Institute of Technology (LTH), is responsible for the basic physics teaching in all subjects at LTH and for specialized teaching in Optics, Atomic Physics, Atomic and Molecular Spectroscopy and Laser Physics. The Division has research activities in basic and applied optical spectroscopy, to a large extent based on lasers. It is also part of the Physics Department, Lund University, where it forms one of eight divisions. Since the beginning of 1980 the research activities of our division have been centred around the use of lasers. The activities during the period 1991-1992 is described in this progress reports

  7. The CHIANTI atomic database

    CERN Document Server

    Young, Peter R; Landi, Enrico; Del Zanna, Giulio; Mason, Helen

    2015-01-01

    The CHIANTI atomic database was first released in 1996 and has had a huge impact on the analysis and modeling of emissions from astrophysical plasmas. The database has continued to be updated, with version 8 released in 2015. Atomic data for modeling the emissivities of 246 ions and neutrals are contained in CHIANTI, together with data for deriving the ionization fractions of all elements up to zinc. The different types of atomic data are summarized here and their formats discussed. Statistics on the impact of CHIANTI to the astrophysical community are given and examples of the diverse range of applications are presented.

  8. Inside the Hydrogen Atom

    CERN Document Server

    Nowakowski, M; Fierro, D Bedoya; Manjarres, A D Bermudez

    2016-01-01

    We apply the non-linear Euler-Heisenberg theory to calculate the electric field inside the hydrogen atom. We will demonstrate that the electric field calculated in the Euler-Heisenberg theory can be much smaller than the corresponding field emerging from the Maxwellian theory. In the hydrogen atom this happens only at very small distances. This effect reduces the large electric field inside the hydrogen atom calculated from the electromagnetic form-factors via the Maxwell equations. The energy content of the field is below the pair production threshold.

  9. Atoms, molecules, solids

    International Nuclear Information System (INIS)

    This book is an introduction to modern physics for undergraduate students of physics or students of related fields. After an introduction to the wave-particle dualism the structure of atoms is considered with regards to atomic models. Then the foundations of quantum mechanics are introduced with regards to their application to atomic structure calculations. Thereafter the chemical bond and the molecular structure are discussed. Then classical and quantum statistical mechanics are introduced. Thereafter the crystal binding, the crystal structure, and the specific heat of solids are considered. Finally the band theory of solids is briefly introduced. Every chapter contains exercise problems. (HSI)

  10. Rydberg atoms in astrophysics

    CERN Document Server

    Gnedin, Yu N; Ignjatovic, Lj M; Sakan, N M; Sreckovic, V A; Zakharov, M Yu; Bezuglov, N N; Klycharev, A N; 10.1016/j.newar.2009.07.003

    2012-01-01

    Elementary processes in astrophysical phenomena traditionally attract researchers attention. At first this can be attributed to a group of hemi-ionization processes in Rydberg atom collisions with ground state parent atoms. This processes might be studied as a prototype of the elementary process of the radiation energy transformation into electrical one. The studies of nonlinear mechanics have shown that so called regime of dynamic chaos should be considered as typical, rather than exceptional situation in Rydberg atoms collision. From comparison of theory with experimental results it follows that a such kind of stochastic dynamic processes, occurred during the single collision, may be observed.

  11. Tightly confined atoms in optical dipole traps

    International Nuclear Information System (INIS)

    This thesis reports on the design and setup of a new atom trap apparatus, which is developed to confine few rubidium atoms in ultrahigh vacuum and make them available for controlled manipulations. To maintain low background pressure, atoms of a vapour cell are transferred into a cold atomic beam by laser cooling techniques, and accumulated by a magneto-optic trap (MOT) in a separate part of the vacuum system. The laser cooled atoms are then transferred into dipole traps made of focused far-off-resonant laser fields in single- or crossed-beam geometry, which are superimposed with the center of the MOT. Gaussian as well as hollow Laguerre-Gaussian (LG$(01)$) beam profiles are used with red-detuned or blue-detuned light, respectively. Microfabricated dielectric phase objects allow efficient and robust mode conversion of Gaussian into Laguerre-Gaussian laser beams. Trap geometries can easily be changed due to the highly flexible experimental setup. The dipole trap laser beams are focused to below 10 microns at a power of several hundred milliwatts. Typical trap parameters, at a detuning of several ten nanometers from the atomic resonance, are trag depths of few millikelvin, trap frequencies near 30-kHz, trap light scattering rates of few hundred photons per atom and second, and lifetimes of several seconds. The number of dipole-trapped atoms ranges from more than ten thousand to below ten. The dipole-trapped atoms are detected either by a photon counting system with very efficient straylight discrimination, or by recapture into the MOT, which is imaged onto a sensitive photodiode and a CCD-camera. Due to the strong AC-Stark shift imposed by the high intensity trapping light, energy-selective resonant excitation and detection of the atoms is possible. The measured energy distribution is consistent with a harmonic potential shape and allows the determination of temperatures and heating rates. In first measurements, the thermal energy is found to be about 10 % of the trap

  12. Accurate atomic data for industrial plasma applications

    Energy Technology Data Exchange (ETDEWEB)

    Griesmann, U.; Bridges, J.M.; Roberts, J.R.; Wiese, W.L.; Fuhr, J.R. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

    1997-12-31

    Reliable branching fraction, transition probability and transition wavelength data for radiative dipole transitions of atoms and ions in plasma are important in many industrial applications. Optical plasma diagnostics and modeling of the radiation transport in electrical discharge plasmas (e.g. in electrical lighting) depend on accurate basic atomic data. NIST has an ongoing experimental research program to provide accurate atomic data for radiative transitions. The new NIST UV-vis-IR high resolution Fourier transform spectrometer has become an excellent tool for accurate and efficient measurements of numerous transition wavelengths and branching fractions in a wide wavelength range. Recently, the authors have also begun to employ photon counting techniques for very accurate measurements of branching fractions of weaker spectral lines with the intent to improve the overall accuracy for experimental branching fractions to better than 5%. They have now completed their studies of transition probabilities of Ne I and Ne II. The results agree well with recent calculations and for the first time provide reliable transition probabilities for many weak intercombination lines.

  13. 78 FR 58571 - Maine Yankee Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic...

    Science.gov (United States)

    2013-09-24

    ... Atomic Power Company, Connecticut Yankee Atomic Power Company, and The Yankee Atomic Electric Company... Power Company (Maine Yankee), Connecticut Yankee Atomic Power Company (Connecticut Yankee), and the Yankee Atomic Electric Company (Yankee Atomic) (together, ``licensees'' or ``the Yankee Companies'')...

  14. Counts of low-Redshift SDSS quasar candidates

    International Nuclear Information System (INIS)

    We analyze the counts of low-redshift quasar candidates selected using nine-epoch SDSS imaging data. The co-added catalogs are more than 1 mag deeper than single-epoch SDSS data, and allow the selection of low-redshift quasar candidates using UV-excess and also variability techniques. The counts of selected candidates are robustly determined down to g = 21.5. This is about 2 magnitudes deeper than the position of a change in the slope of the counts reported by Boyle (and others) (1990, 2000) for a sample selected by UV-excess, and questioned by Hawkins and Veron (1995), who utilized a variability-selected sample. Using SDSS data, we confirm a change in the slope of the counts for both UV-excess and variability selected samples, providing strong support for the Boyle (and others) results

  15. Microfluidic Cytometer for Complete Blood Count Analysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We will fabricate and test microfluidic designs for a micro-electromechanical system based complete blood count (CBC) analysis in separate modules and integrate...

  16. Calibration of sample channel ratio (SCR) in liquid scintillation counting

    International Nuclear Information System (INIS)

    In PHWR type nuclear power plants tritium is a major internal exposure hazard for the plant personnel. The dose due to tritium is measured by periodic analysis of urine samples by the liquid scintillation counting method. Due to the coloured and other impurity content in the urine, varying levels of quenching of the counts occur, thereby affecting the liquid scintillation counting efficiency. In using the sample channel ratio (SCR) method of quench correction it was observed that a single calibration curve does not hold good for all types of urine samples. The variations seem to result due to different quench characteristics applicable to the coloured and colourless samples. Hence the urine samples are segregated into coloured and colourless samples using a UV-spectrophotometer and separate calibration curves are drawn for these. The use of the appropriate calibration curves for the urine samples minimises the errors associated with quenching during tritium measurement by liquid scintillation counting. (author). 1 tab., 1 fig

  17. Fitting a distribution to miccrobial counts: making sense of zeros

    DEFF Research Database (Denmark)

    Ribeiro Duarte, Ana Sofia; Stockmarr, Anders; Nauta, Maarten

    “artificial zeros” are only a share of the total number of zero counts resulting from a sample, as their number adds up to the number of “true zeros” resulting from uncontaminated units. In the process of fitting a probability distribution to microbial counts, “artificial” and “true” zeros are usually...... standard deviation) and the prevalence of contaminated food units (one minus the proportion of “true zeros”) from a set of microbial counts. By running the model with in silico generated concentration and count data, we could evaluate the performance of this method in terms of estimation of the three...... of the distribution parameters mean and standard deviation by running the same model for different prevalence scenarios....

  18. A new method for counting trees with vertex partition

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A direct and elementary method is provided in this paper for counting trees with vertex partition instead of recursion, generating function, functional equation, Lagrange inversion, and matrix methods used before.

  19. Butterfly Count 2001 Wallkill River National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These are the data sheets from the annual butterfly count at Wallkill River National Wildlife Refuge for 2001. There were 20 people involved in this one-day survey.

  20. Butterfly Count 2002 Wallkill River National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These are the data sheets from the annual butterfly count at Wallkill River National Wildlife Refuge for 2002. There were 20 people involved in this one-day survey.