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Sample records for crossover interference count

  1. Interference-mediated synaptonemal complex formation with embedded crossover designation

    PubMed Central

    Zhang, Liangran; Espagne, Eric; de Muyt, Arnaud; Zickler, Denise; Kleckner, Nancy E.

    2014-01-01

    Biological systems exhibit complex patterns at length scales ranging from the molecular to the organismic. Along chromosomes, events often occur stochastically at different positions in different nuclei but nonetheless tend to be relatively evenly spaced. Examples include replication origin firings, formation of chromatin loops along chromosome axes and, during meiosis, localization of crossover recombination sites (“crossover interference”). We present evidence in the fungus Sordaria macrospora that crossover interference is part of a broader pattern that includes synaptonemal complex (SC) nucleation. This pattern comprises relatively evenly spaced SC nucleation sites, among which a subset are crossover sites that show a classical interference distribution. This pattern ensures that SC forms regularly along the entire length of the chromosome as required for the maintenance of homolog pairing while concomitantly having crossover interactions locally embedded within the SC structure as required for both DNA recombination and structural events of chiasma formation. This pattern can be explained by a threshold-based designation and spreading interference process. This model can be generalized to give diverse types of related and/or partially overlapping patterns, in two or more dimensions, for any type of object. PMID:25380597

  2. Effect of sex, age and genetics on crossover interference in cattle

    PubMed Central

    Wang, Zhiying; Shen, Botong; Jiang, Jicai; Li, Jinquan; Ma, Li

    2016-01-01

    Crossovers generated by homologous recombination ensure proper chromosome segregation during meiosis. Crossover interference results in chiasmata being more evenly distributed along chromosomes, but the mechanism underlying crossover interference remains elusive. Based on large pedigrees of Holstein and Jersey cattle with genotype data, we extracted three-generation families, including 147,327 male and 71,687 female meioses in Holstein, and 108,163 male and 37,008 female meioses in Jersey, respectively. We identified crossovers in these meioses and fitted the Housworth-Stahl “interference-escape” model to study crossover interference patterns in the cattle genome. Our result reveals that the degree of crossover interference is stronger in females than in males. We found evidence for inter-chromosomal variation in the level of crossover interference, with smaller chromosomes exhibiting stronger interference. In addition, crossover interference levels decreased with maternal age. Finally, sex-specific GWAS analyses identified one locus near the NEK9 gene on chromosome 10 to have a significant effect on crossover interference levels. This locus has been previously associated with recombination rate in cattle. Collectively, this large-scale analysis provided a comprehensive description of crossover interference across chromosome, sex and age groups, identified associated candidate genes, and produced useful insights into the mechanism of crossover interference. PMID:27892966

  3. Concurrent counting and typing: lateralized interference depends on a difference between the hands in motor skill.

    PubMed

    Hiscock, Merrill; Caroselli, Jerome S; Wood, Stacey

    2006-01-01

    In previous demonstrations of differences between left- and right-handers in dual-task performance, participants' hand preference has been confounded with asymmetry of manual skill. The present study was designed to disentangle those two factors as sources of lateralized interference in the concurrent-task paradigm. Forty-eight normal adults (24 females and 24 males) counted backward by ones or by twos while typing an easy or difficult sequence of letters with either hand. When participants were grouped according to self-reported hand preference, both groups showed bilaterally symmetric slowing, relative to single-task conditions. However, when the same participants were grouped according to manual asymmetry in the baseline condition, the cognitive task interfered significantly more with the faster hand than with the slower hand. Baseline typing rate, averaged across hands, did not influence dual-task interference. Both self-reported left-hand preference and left-hand superiority in baseline typing were associated with reduced interference on the cognitive task, and the reduced interference in those groups seemed to reflect relatively loose coupling between manual and cognitive tasks. The results support and extend Caroselli et al.'s (1997) findings regarding the effect of baseline manual asymmetry on the pattern of dual-task interference. Irrespective of the participant's hand preference, the presence or absence of baseline asymmetry may be sufficient to determine whether dual-task interference is lateralized.

  4. Full counting statistics of the interference contrast from independent Bose-Einstein condensates

    SciTech Connect

    Rath, Steffen Patrick; Zwerger, Wilhelm

    2010-11-15

    We show that the visibility in interference experiments with Bose-Einstein condensates is directly related to the condensate fraction. The probability distribution of the contrast over many runs of an interference experiment thus gives the full counting statistics of the condensed atom number. For two-dimensional Bose gases, we discuss the universal behavior of the probability distribution in the superfluid regime and provide analytical expressions for the distributions for both homogeneous and harmonically trapped samples. They are non-Gaussian and unimodal with a variance that is directly related to the superfluid density. In general, the visibility is a self-averaging observable only in the presence of long-range phase coherence. Close to the transition temperature, the visibility distribution reflects the universal order-parameter distribution in the vicinity of the critical point.

  5. Accurate cell counts in live mouse embryos using optical quadrature and differential interference contrast microscopy

    NASA Astrophysics Data System (ADS)

    Warger, William C., II; Newmark, Judith A.; Zhao, Bing; Warner, Carol M.; DiMarzio, Charles A.

    2006-02-01

    Present imaging techniques used in in vitro fertilization (IVF) clinics are unable to produce accurate cell counts in developing embryos past the eight-cell stage. We have developed a method that has produced accurate cell counts in live mouse embryos ranging from 13-25 cells by combining Differential Interference Contrast (DIC) and Optical Quadrature Microscopy. Optical Quadrature Microscopy is an interferometric imaging modality that measures the amplitude and phase of the signal beam that travels through the embryo. The phase is transformed into an image of optical path length difference, which is used to determine the maximum optical path length deviation of a single cell. DIC microscopy gives distinct cell boundaries for cells within the focal plane when other cells do not lie in the path to the objective. Fitting an ellipse to the boundary of a single cell in the DIC image and combining it with the maximum optical path length deviation of a single cell creates an ellipsoidal model cell of optical path length deviation. Subtracting the model cell from the Optical Quadrature image will either show the optical path length deviation of the culture medium or reveal another cell underneath. Once all the boundaries are used in the DIC image, the subtracted Optical Quadrature image is analyzed to determine the cell boundaries of the remaining cells. The final cell count is produced when no more cells can be subtracted. We have produced exact cell counts on 5 samples, which have been validated by Epi-Fluorescence images of Hoechst stained nuclei.

  6. Studying the optical second-order interference pattern formation process with classical light in the photon counting regime.

    PubMed

    He, Yuchen; Liu, Jianbin; Zhang, Songlin; Wang, Wentao; Bai, Bin; Le, Mingnan; Xu, Zhuo

    2015-12-01

    The formation process of the second-order interference pattern is studied experimentally in the photon counting regime by superposing two independent single-mode continuous-wave lasers. Two-photon interference based on the superposition principle in Feynman's path integral theory is employed to interpret the experimental results. The second-order interference pattern of classical light can be formulated when, with high probability, there are only two photons in the interferometer at one time. The studies are helpful in understanding the second-order interference of classical light in the language of photons. The method and conclusions can be generalized to the third- and higher-order interference of light and interference of massive particles.

  7. Chip-interleaved optical code division multiple access relying on a photon-counting iterative successive interference canceller for free-space optical channels.

    PubMed

    Zhou, Xiaolin; Zheng, Xiaowei; Zhang, Rong; Hanzo, Lajos

    2013-07-01

    In this paper, we design a novel Poisson photon-counting based iterative successive interference cancellation (SIC) scheme for transmission over free-space optical (FSO) channels in the presence of both multiple access interference (MAI) as well as Gamma-Gamma atmospheric turbulence fading, shot-noise and background light. Our simulation results demonstrate that the proposed scheme exhibits a strong MAI suppression capability. Importantly, an order of magnitude of BER improvements may be achieved compared to the conventional chip-level optical code-division multiple-access (OCDMA) photon-counting detector.

  8. The choice in meiosis - defining the factors that influence crossover or non-crossover formation.

    PubMed

    Youds, Jillian L; Boulton, Simon J

    2011-02-15

    Meiotic crossovers are essential for ensuring correct chromosome segregation as well as for creating new combinations of alleles for natural selection to take place. During meiosis, excess meiotic double-strand breaks (DSBs) are generated; a subset of these breaks are repaired to form crossovers, whereas the remainder are repaired as non-crossovers. What determines where meiotic DSBs are created and whether a crossover or non-crossover will be formed at any particular DSB remains largely unclear. Nevertheless, several recent papers have revealed important insights into the factors that control the decision between crossover and non-crossover formation in meiosis, including DNA elements that determine the positioning of meiotic DSBs, and the generation and processing of recombination intermediates. In this review, we focus on the factors that influence DSB positioning, the proteins required for the formation of recombination intermediates and how the processing of these structures generates either a crossover or non-crossover in various organisms. A discussion of crossover interference, assurance and homeostasis, which influence crossing over on a chromosome-wide and genome-wide scale - in addition to current models for the generation of interference - is also included. This Commentary aims to highlight recent advances in our understanding of the factors that promote or prevent meiotic crossing over.

  9. Tower counts

    USGS Publications Warehouse

    Woody, Carol Ann; Johnson, D.H.; Shrier, Brianna M.; O'Neal, Jennifer S.; Knutzen, John A.; Augerot, Xanthippe; O'Neal, Thomas A.; Pearsons, Todd N.

    2007-01-01

    Counting towers provide an accurate, low-cost, low-maintenance, low-technology, and easily mobilized escapement estimation program compared to other methods (e.g., weirs, hydroacoustics, mark-recapture, and aerial surveys) (Thompson 1962; Siebel 1967; Cousens et al. 1982; Symons and Waldichuk 1984; Anderson 2000; Alaska Department of Fish and Game 2003). Counting tower data has been found to be consistent with that of digital video counts (Edwards 2005). Counting towers do not interfere with natural fish migration patterns, nor are fish handled or stressed; however, their use is generally limited to clear rivers that meet specific site selection criteria. The data provided by counting tower sampling allow fishery managers to determine reproductive population size, estimate total return (escapement + catch) and its uncertainty, evaluate population productivity and trends, set harvest rates, determine spawning escapement goals, and forecast future returns (Alaska Department of Fish and Game 1974-2000 and 1975-2004). The number of spawning fish is determined by subtracting subsistence, sport-caught fish, and prespawn mortality from the total estimated escapement. The methods outlined in this protocol for tower counts can be used to provide reasonable estimates ( plus or minus 6%-10%) of reproductive salmon population size and run timing in clear rivers. 

  10. [Cross-over studies].

    PubMed

    Bonten, Tobias N; Siegerink, Bob; van der Bom, Johanna G

    2013-01-01

    Randomized, parallel group clinical trials often require large groups of patients; this is expensive and takes time. A randomized cross-over trial can be an efficient and more affordable alternative. A cross-over design can be used to study chronic disorders in which treatments have temporary effects. Participants receive all treatments in consecutive periods and outcomes are measured after every period. In general, only a quarter of the total group size is needed for cross-over studies compared with parallel group studies. Results can be affected by period-effects and carry-over-effects, which can be prevented through randomization and a wash-out period of sufficient length. The dropping-out of participants has more negative consequences for cross-over studies than for parallel group studies.

  11. RNA Interference

    MedlinePlus

    ... NIGMS Home > Science Education > RNA Interference Fact Sheet RNA Interference Fact Sheet Tagline (Optional) Middle/Main Content Area What is RNA interference? RNA interference (RNAi) is a natural process ...

  12. WBC count

    MedlinePlus

    Leukocyte count; White blood cell count ... blood is 4,500 to 11,000 white blood cells per microliter (mcL) or 4.5 to 11. ... LOW WHITE BLOOD CELL (WBC) COUNT A low number of WBCs is called leukopenia. A WBC count below 4500 is below normal ...

  13. Low serum enterolactone concentration is associated with low colonic Lactobacillus-Enterococcus counts in men but is not affected by a synbiotic mixture in a randomised, placebo-controlled, double-blind, cross-over intervention study.

    PubMed

    Holma, Reetta; Kekkonen, Riina A; Hatakka, Katja; Poussa, Tuija; Vapaatalo, Heikki; Adlercreutz, Herman; Korpela, Riitta

    2014-01-28

    The aims of the present study were to assess the possible differences in faecal microbiota between men with a low serum enterolactone concentration and those with a high concentration, and to investigate the impact of a synbiotic mixture on serum enterolactone concentration in men with a low concentration. We compared faecal microbiota between ten men with the lowest serum enterolactone concentration and ten men with the highest concentration at recruitment (n 84). Furthermore, we carried out a randomised, double-blind, placebo-controlled, cross-over intervention study (6-week intervention periods and 4-week washout period) to investigate the impact of a synbiotic mixture (two Lactobacillus strains, one Bifidobacterium strain, one Propionibacterium strain and galacto-oligosaccharides (32 g/l)) on serum enterolactone concentration in fifty-two men who had a concentration < 20 nmol/l. Serum sensitive C-reactive protein (CRP) concentration was measured at the end of the first intervention period. Men with a low serum enterolactone concentration when compared with those with a high concentration had less faecal bacteria, especially those belonging to the Lactobacillus-Enterococcus group (median 8·2 (interquartile range 7·8-8·4) log10 colony-forming units/g v. median 8·8 (interquartile range 8·5-8·9) log10 colony-forming units/g, P= 0·009). The synbiotic mixture that was used did not have a significant effect on serum enterolactone (synbiotic v. placebo ratio 0·96 (95 % CI 0·76, 1·22), P= 0·724) or serum sensitive CRP (synbiotic v. placebo ratio 0·99 (95 % CI 0·74, 1·33), P= 0·954) concentration. Men with a low serum enterolactone concentration harbour less colonic bacteria, especially those belonging to the Lactobacillus-Enterococcus group. A synbiotic mixture does not increase serum enterolactone concentration.

  14. Crossover behavior in interface depinning.

    PubMed

    Chen, Y J; Zapperi, Stefano; Sethna, James P

    2015-08-01

    We study the crossover scaling behavior of the height-height correlation function in interface depinning in random media. We analyze experimental data from a fracture experiment and simulate an elastic line model with nonlinear couplings and disorder. Both exhibit a crossover between two different universality classes. For the experiment, we fit a functional form to the universal crossover scaling function. For the model, we vary the system size and the strength of the nonlinear term and describe the crossover between the two universality classes with a multiparameter scaling function. Our method provides a general strategy to extract scaling properties in depinning systems exhibiting crossover phenomena.

  15. Multiplicity Counting

    SciTech Connect

    Geist, William H.

    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.

  16. RBC count

    MedlinePlus

    ... marrow disease that causes abnormal increase in RBCs ( polycythemia vera ) Your RBC count will increase for several ... Multiple myeloma Myelofibrosis Paroxysmal nocturnal hemoglobinuria (PNH) Peripheral Polycythemia vera Renal cell carcinoma Splenomegaly Transfusion reaction - hemolytic ...

  17. Reticulocyte count

    MedlinePlus

    Anemia - reticulocyte ... A higher than normal reticulocytes count may indicate: Anemia due to red blood cells being destroyed earlier than normal ( hemolytic anemia ) Bleeding Blood disorder in a fetus or newborn ( ...

  18. White Blood Cell Count

    MedlinePlus

    ... limited. Home Visit Global Sites Search Help? White Blood Cell Count Share this page: Was this page helpful? ... Count; Leukocyte Count; White Count Formal name: White Blood Cell Count Related tests: Complete Blood Count , Blood Smear , ...

  19. Counting Populations

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

    Scientists use sampling to get an estimate of things they cannot easily count. A population is made up of all the organisms of one species living together in one place at the same time. All of the people living together in one town are considered a population. All of the grasshoppers living in a field are a population. Scientists keep track of the…

  20. Counting Penguins.

    ERIC Educational Resources Information Center

    Perry, Mike; Kader, Gary

    1998-01-01

    Presents an activity on the simplification of penguin counting by employing the basic ideas and principles of sampling to teach students to understand and recognize its role in statistical claims. Emphasizes estimation, data analysis and interpretation, and central limit theorem. Includes a list of items for classroom discussion. (ASK)

  1. Crossover studies with survival outcomes.

    PubMed

    Buyze, Jozefien; Goetghebeur, Els

    2013-12-01

    Crossover designs are well known to have major advantages when comparing the effect of two treatments which do not interact. With a right-censored survival endpoint, however, this design is quickly abandoned in favour of the more costly parallel design. Motivated by human immunodeficiency virus (HIV) prevention studies which lacked power, we evaluate what may be gained in this setting and compare parallel with crossover designs. In a heterogeneous population, we find and explain a substantial increase in power for the crossover study using a non-parametric logrank test. With frailties in a proportional hazards model, crossover designs equally lead to substantially smaller variance for the subject-specific hazard ratio (HR), while the population-averaged HR sees negligible gain. Its efficiency benefit is recovered when the population-averaged HR is reconstructed from estimated subject-specific hazard rates. We derive the time point for treatment crossover that optimizes efficiency and end with the analysis of two recent HIV prevention trials. We find that a Cellulose sulphate trial could have hardly gained efficiency from a crossover design, while a Nonoxynol-9 trial stood to gain substantial power. We conclude that there is a role for effective crossover designs in important classes of survival problems.

  2. 24 CFR 3285.701 - Electrical crossovers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ....701 Electrical crossovers. Multi-section homes with electrical wiring in more than one section require crossover connections to join all sections of the home. The crossover must be designed in accordance with... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Electrical crossovers....

  3. Reticulocyte Count Test

    MedlinePlus

    ... Reticulocyte Count Related tests: Red Blood Cell Count ; Hemoglobin ; Hematocrit ; Complete Blood Count ; Blood Smear ; Erythropoietin ; Vitamin ... on a complete blood count (CBC) , RBC count , hemoglobin or hematocrit , to help determine the cause To ...

  4. The BCS-BEC Crossover

    NASA Astrophysics Data System (ADS)

    Parish, Meera M.

    2015-09-01

    This chapter presents the crossover from the Bardeen-Cooper-Schrieffer (BCS) state of weakly correlated pairs of fermions to the Bose-Einstein condensation (BEC) of diatomic molecules in the atomic Fermi gas. Our aim is to provide a pedagogical review of the BCS-BEC crossover, with an emphasis on the basic concepts, particularly those that are not generally known or are difficult to find in the literature. We shall not attempt to give an exhaustive survey of current research in the limited space here; where possible, we will direct the reader to more extensive reviews.

  5. Tunneling above the crossover temperature.

    PubMed

    Alvarez-Barcia, Sonia; Flores, Jesús R; Kästner, Johannes

    2014-01-09

    Quantum mechanical tunneling of atoms plays a significant role in many chemical reactions. The crossover temperature between classical and quantum movement is a convenient preliminary indication of the importance of tunneling for a particular reaction. Here we show, using instanton theory, that quantum tunneling is possible significantly above this crossover temperature for specific forms of the potential energy surface. We demonstrate the effect on an analytic potential as well as a chemical system. While protons move asynchronously along a Grotthuss chain in the classical high-temperature range, the onset of tunneling results in a synchronization of their movement.

  6. Microelectronic superconducting crossover and coil

    DOEpatents

    Wellstood, Frederick C.; Kingston, John J.; Clarke, John

    1994-01-01

    A microelectronic component comprising a crossover is provided comprising a substrate, a first high T.sub.c superconductor thin film, a second insulating thin film comprising SrTiO.sub.3 ; and a third high T.sub.c superconducting film which has strips which crossover one or more areas of the first superconductor film. An in situ method for depositing all three films on a substrate is provided which does not require annealing steps and which can be opened to the atmosphere between depositions.

  7. Microelectronic superconducting crossover and coil

    DOEpatents

    Wellstood, F.C.; Kingston, J.J.; Clarke, J.

    1994-03-01

    A microelectronic component comprising a crossover is provided comprising a substrate, a first high T[sub c] superconductor thin film, a second insulating thin film comprising SrTiO[sub 3]; and a third high T[sub c] superconducting film which has strips which crossover one or more areas of the first superconductor film. An in situ method for depositing all three films on a substrate is provided which does not require annealing steps and which can be opened to the atmosphere between depositions. 13 figures.

  8. 30 CFR 57.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Conveyor crossovers. 57.11013 Section 57.11013... Escapeways Travelways-Surface and Underground § 57.11013 Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  9. 30 CFR 57.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Conveyor crossovers. 57.11013 Section 57.11013... Escapeways Travelways-Surface and Underground § 57.11013 Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  10. 30 CFR 56.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Conveyor crossovers. 56.11013 Section 56.11013 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  11. 30 CFR 57.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Conveyor crossovers. 57.11013 Section 57.11013... Escapeways Travelways-Surface and Underground § 57.11013 Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  12. 30 CFR 56.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Conveyor crossovers. 56.11013 Section 56.11013 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  13. 30 CFR 56.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Conveyor crossovers. 56.11013 Section 56.11013 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  14. 30 CFR 57.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Conveyor crossovers. 57.11013 Section 57.11013... Escapeways Travelways-Surface and Underground § 57.11013 Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  15. 30 CFR 56.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyor crossovers. 56.11013 Section 56.11013 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  16. 30 CFR 56.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Conveyor crossovers. 56.11013 Section 56.11013 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  17. 30 CFR 57.11013 - Conveyor crossovers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Conveyor crossovers. 57.11013 Section 57.11013... Escapeways Travelways-Surface and Underground § 57.11013 Conveyor crossovers. Crossovers shall be provided where it is necessary to cross conveyors....

  18. Dimensional crossover in semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    McDonald, Matthew P.; Chatterjee, Rusha; Si, Jixin; Jankó, Boldizsár; Kuno, Masaru

    2016-08-01

    Recent advances in semiconductor nanostructure syntheses provide unprecedented control over electronic quantum confinement and have led to extensive investigations of their size- and shape-dependent optical/electrical properties. Notably, spectroscopic measurements show that optical bandgaps of one-dimensional CdSe nanowires are substantially (approximately 100 meV) lower than their zero-dimensional counterparts for equivalent diameters spanning 5-10 nm. But what, exactly, dictates the dimensional crossover of a semiconductor's electronic structure? Here we probe the one-dimensional to zero-dimensional transition of CdSe using single nanowire/nanorod absorption spectroscopy. We find that carrier electrostatic interactions play a fundamental role in establishing dimensional crossover. Moreover, the critical length at which this transition occurs is governed by the aspect ratio-dependent interplay between carrier confinement and dielectric contrast/confinement energies.

  19. Dimensional crossover in semiconductor nanostructures

    PubMed Central

    McDonald, Matthew P.; Chatterjee, Rusha; Si, Jixin; Jankó, Boldizsár; Kuno, Masaru

    2016-01-01

    Recent advances in semiconductor nanostructure syntheses provide unprecedented control over electronic quantum confinement and have led to extensive investigations of their size- and shape-dependent optical/electrical properties. Notably, spectroscopic measurements show that optical bandgaps of one-dimensional CdSe nanowires are substantially (approximately 100 meV) lower than their zero-dimensional counterparts for equivalent diameters spanning 5–10 nm. But what, exactly, dictates the dimensional crossover of a semiconductor's electronic structure? Here we probe the one-dimensional to zero-dimensional transition of CdSe using single nanowire/nanorod absorption spectroscopy. We find that carrier electrostatic interactions play a fundamental role in establishing dimensional crossover. Moreover, the critical length at which this transition occurs is governed by the aspect ratio-dependent interplay between carrier confinement and dielectric contrast/confinement energies. PMID:27577091

  20. Crossover behavior in driven cascades.

    PubMed

    Burridge, James

    2013-09-01

    We propose a model which explains how power-law crossover behavior can arise in a system which is capable of experiencing cascading failure. In our model the susceptibility of the system to cascades is described by a single number, the propagation power, which measures the ease with which cascades propagate. Physically, such a number could represent the density of unstable material in a system, its internal connectivity, or the mean susceptibility of its component parts to failure. We assume that the propagation power follows an upward drifting Brownian motion between cascades, and drops discontinuously each time a cascade occurs. Cascades are described by a continuous state branching process with distributional properties determined by the value of the propagation power when they occur. In common with many cascading models, pure power-law behavior is exhibited at a critical level of propagation power, and the mean cascade size diverges. This divergence constrains large systems to the subcritical region. We show that as a result, crossover behavior appears in the cascade distribution when an average is performed over the distribution of propagation power. We are able to analytically determine the exponents before and after the crossover.

  1. Underbarrier interference

    SciTech Connect

    Ivlev, B.

    2011-04-15

    Research Highlights: > In tunneling a momentum, tangent to a border of the prebarrier region, is important. > A tangent momentum, transferred under the barrier, is real in contrast to normal one. > Real momenta lead to caustics points under the barrier where new branches are formed. > Resulting eigenstate can be not small after the barrier. > This results in a possibility of penetration through an almost classical barrier. - Abstract: Quantum tunneling through a two-dimensional static barrier becomes unusual when a momentum of an electron has a tangent component with respect to a border of the prebarrier region. If the barrier is not homogeneous in the direction perpendicular to tunneling a fraction of the electron state is waves propagating away from the barrier. When the tangent momentum is zero a mutual interference of the waves results in an exponentially small outgoing flux. The finite tangent momentum destroys the interference due to formation of caustics by the waves. As a result, a significant fraction of the prebarrier density is carried away from the barrier providing a not exponentially small penetration even through an almost classical barrier. The total electron energy is well below the barrier.

  2. The BCS Bose crossover theory

    NASA Astrophysics Data System (ADS)

    Adhikari, S. K.; de Llano, M.; Sevilla, F. J.; Solís, M. A.; Valencia, J. J.

    2007-03-01

    We contrast four distinct versions of the BCS-Bose statistical crossover theory according to the form assumed for the electron-number equation that accompanies the BCS gap equation. The four versions correspond to explicitly accounting for two-hole-(2h) as well as two-electron-(2e) Cooper pairs (CPs), or both in equal proportions, or only either kind. This follows from a recent generalization of the Bose-Einstein condensation (GBEC) statistical theory that includes not boson-boson interactions but rather 2e- and also (without loss of generality) 2h-CPs interacting with unpaired electrons and holes in a single-band model that is easily converted into a two-band model. The GBEC theory is essentially an extension of the Friedberg-Lee 1989 BEC theory of superconductors that excludes 2h-CPs. It can thus recover, when the numbers of 2h- and 2e-CPs in both BE-condensed and non-condensed states are separately equal, the BCS gap equation for all temperatures and couplings as well as the zero-temperature BCS (rigorous-upper-bound) condensation energy for all couplings. But ignoring either 2h- or 2e-CPs it can do neither. In particular, only half the BCS condensation energy is obtained in the two crossover versions ignoring either kind of CPs. We show how critical temperatures Tc from the original BCS-Bose crossover theory in 2D require unphysically large couplings for the Cooper/BCS model interaction to differ significantly from the Tcs of ordinary BCS theory (where the number equation is substituted by the assumption that the chemical potential equals the Fermi energy).

  3. Ordering and dimensional crossovers in metallic glasses and liquids

    NASA Astrophysics Data System (ADS)

    Chen, David Z.; An, Qi; Goddard, William A.; Greer, Julia R.

    2017-01-01

    The atomic-level structures of liquids and glasses are amorphous, lacking long-range order. We characterize the atomic structures by integrating radial distribution functions (RDF) from molecular dynamics (MD) simulations for several metallic liquids and glasses: C u46Z r54 , N i80A l20 , N i33.3Z r66.7 , and P d82S i18 . Resulting cumulative coordination numbers (CN) show that metallic liquids have a dimension of d =2.55 ±0.06 from the center atom to the first coordination shell and metallic glasses have d =2.71 ±0.04 , both less than 3. Between the first and second coordination shells, both phases crossover to a dimension of d =3 , as for a crystal. Observations from discrete atom center-of-mass position counting are corroborated by continuously counting Cu glass- and liquid-phase atoms on an artificial grid, which accounts for the occupied atomic volume. Results from Cu grid analysis show short-range d =2.65 for Cu liquid and d =2.76 for Cu glass. Cu grid structures crossover to d =3 at ξ ˜8 Å (˜3 atomic diameters). We study the evolution of local structural dimensions during quenching and discuss its correlation with the glass transition phenomenon.

  4. Becoming a crossover-competent DSB.

    PubMed

    Lake, Cathleen M; Hawley, R Scott

    2016-06-01

    The proper execution of meiotic recombination (or crossing over) is essential for chromosome segregation during the first meiotic division, and thus this process is regulated by multiple, and often elaborate, mechanisms. Meiotic recombination begins with the programmed induction of DNA double-strand breaks (DSBs), of which only a subset are selected to be repaired into crossovers. This crossover selection process is carried out by a number of pro-crossover proteins that regulate the fashion in which DSBs are repaired. Here, we highlight recent studies regarding the process of DSB fate selection by a family of pro-crossover proteins known as the Zip-3 homologs.

  5. All about Carbohydrate Counting

    MedlinePlus

    Toolkit No. 14 All About Carbohydrate Counting What is carbohydrate counting? Carbohydrate counting is a way to plan your meals. It can help ... Diabetes Association, Inc. 2/14 Toolkit No. 14: All About Carbohydrate Counting continued The chart at the ...

  6. 24 CFR 3285.701 - Electrical crossovers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Electrical crossovers. 3285.701... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Electrical Systems and Equipment § 3285.701 Electrical crossovers. Multi-section homes with electrical wiring in more than one section...

  7. 24 CFR 3285.701 - Electrical crossovers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Electrical crossovers. 3285.701... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Electrical Systems and Equipment § 3285.701 Electrical crossovers. Multi-section homes with electrical wiring in more than one section...

  8. 24 CFR 3285.701 - Electrical crossovers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Electrical crossovers. 3285.701... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Electrical Systems and Equipment § 3285.701 Electrical crossovers. Multi-section homes with electrical wiring in more than one section...

  9. 24 CFR 3285.701 - Electrical crossovers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Electrical crossovers. 3285.701... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Electrical Systems and Equipment § 3285.701 Electrical crossovers. Multi-section homes with electrical wiring in more than one section...

  10. The Big Pumpkin Count.

    ERIC Educational Resources Information Center

    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)

  11. Crossover critical phenomena in fluids

    NASA Astrophysics Data System (ADS)

    Kostrowicka Wyczalkowska, Anna Judyta

    In fluids the effects of critical density fluctuations remain significant over a large range of temperatures and densities. The nonanalytical behavior observed in real fluids in the vicinity of the critical point is well described by renormalization-group theory. This theory accounts properly for the influence of the critical fluctuations in density which are entirely neglected by the classical equations. Specifically, fluids asymptotically close to the critical point belong to the universality class of the 3-dimensional Ising model and their behavior near the critical point is governed by scaling laws with critical exponents appropriate for this universality class. The validity of the asymptotic power laws is, however, restricted to a very small region near the critical point. An approach to deal with the nonasymptotic behavior of fluids including the crossover from Ising behavior in the immediate vicinity of the critical point to classical behavior far away from the critical point has been developed by Chen and coworkers and is further improved in this thesis. This approach is based on earlier work of Nicoll and coworkers and it leads to a transformation of a classical Landau expansion to incorporate the effects of critical fluctuations. Here we show how this transformation applies to real fluids: water and sulfurhexafluoride. Nevertheless, even such a crossover Landau expansion still fails to make a connection with the behavior of the fluid very far away from the critical point like the ideal-gas limit at low densities. We demonstrate how a procedure, earlier developed to include the effects of critical fluctuations into a classical Landau expansion of the Helmholtz-energy density, can also be applied to a closed-form classical equation of state like the equation of van der Waals. One of the consequences of accounting for the presence of the critical fluctuations is a shift in the location of the critical point. The resulting equation incorporates the

  12. Magic angle effects and angular magnetoresistance oscillations as dimensional crossovers.

    PubMed

    Lebed, A G; Bagmet, N N; Naughton, M J

    2004-10-08

    Interference effects between velocity and density of states, which occur as electrons move along open orbits in the extended Brillouin zone in anisotropic conductors, result in a change of wave functions' dimensionality at magic angle (MA) directions of a magnetic field. In particular, these 1D-->2D dimensional crossovers result in the appearance of sharp minima in a resistivity component rho perpendicular (H,alpha), perpendicular to conducting layers. This explains the main qualitative features of MA and angular magnetoresistance oscillations' phenomena observed due to the existence of quasi-one-dimensional sheets of Fermi surface in (TMTSF)2X, (DMET-TSeF)2X, and kappa-(ET)2Cu(NCS)(2) conductors.

  13. Observation of a crossover in kinetic aggregation of Palladium colloids

    NASA Astrophysics Data System (ADS)

    Ghafari, M.; Ranjbar, M.; Rouhani, S.

    2015-10-01

    We use field emission scanning electron microscope (FE-SEM) to investigate the growth of palladium colloids over the surface of thin films of WO3/glass. The film is prepared by Pulsed Laser Deposition (PLD) at different temperatures. A PdCl2 (aq) droplet is injected on the surface and in the presence of steam hydrogen the droplet is dried through a reduction reaction process. Two distinct aggregation regimes of palladium colloids are observed over the substrates. We argue that the change in aggregation dynamics emerges when the measured water drop Contact Angel (CA) for the WO3/glass thin films passes a certain threshold value, namely CA ≈ 46°, where a crossover in kinetic aggregation of palladium colloids occurs. Our results suggest that the mass fractal dimension of palladium aggregates follows a power-law behavior. The fractal dimension (Df) in the fast aggregation regime, where the measured CA values vary from 27° up to 46° according to different substrate deposition temperatures, is Df = 1.75(± 0.02) - the value of Df is in excellent agreement with kinetic aggregation of other colloidal systems in fast aggregation regime. Whereas for the slow aggregation regime, with CA = 58°, the fractal dimension changes abruptly to Df = 1.92(± 0.03). We have also used a modified Box-Counting method to calculate fractal dimension of gray-level images and observe that the crossover at around CA ≈ 46° remains unchanged.

  14. The Misguided Ethics of Crossover Trials

    PubMed Central

    Prasad, Vinay; Grady, Christine

    2014-01-01

    Crossover is increasingly favored in trials of cancer therapies; even those that seek to establish the basic efficacy of novel drugs. Crossover is done in part for trial recruitment, but also out of a sense of doing the right thing—offering the investigational agent to more patients. In this paper, we argue that this ethical feeling—that crossover is a preferred trial choice—is misguided. In seeking to sate the desires of participants, we might undermine a trial’s ability to answer a meaningful clinical question. When a trial is incapable of answering a question, it becomes unethical. Using a crossover strategy in oncology clinical trials can make trials less ethical, not more. L’enfer est plein de bonnes volontés et désirs (Hell is full of good wishes and desires)--Saint Bernard of Clairvaux (c.1150) PMID:24365533

  15. Design, analysis, and presentation of crossover trials

    PubMed Central

    Mills, Edward J; Chan, An-Wen; Wu, Ping; Vail, Andy; Guyatt, Gordon H; Altman, Douglas G

    2009-01-01

    Objective Although crossover trials enjoy wide use, standards for analysis and reporting have not been established. We reviewed methodological aspects and quality of reporting in a representative sample of published crossover trials. Methods We searched MEDLINE for December 2000 and identified all randomized crossover trials. We abstracted data independently, in duplicate, on 14 design criteria, 13 analysis criteria, and 14 criteria assessing the data presentation. Results We identified 526 randomized controlled trials, of which 116 were crossover trials. Trials were drug efficacy (48%), pharmacokinetic (28%), and nonpharmacologic (30%). The median sample size was 15 (interquartile range 8–38). Most (72%) trials used 2 treatments and had 2 periods (64%). Few trials reported allocation concealment (17%) or sequence generation (7%). Only 20% of trials reported a sample size calculation and only 31% of these considered pairing of data in the calculation. Carry-over issues were addressed in 29% of trial's methods. Most trials reported and defended a washout period (70%). Almost all trials (93%) tested for treatment effects using paired data and also presented details on by-group results (95%). Only 29% presented CIs or SE so that data could be entered into a meta-analysis. Conclusion Reports of crossover trials frequently omit important methodological issues in design, analysis, and presentation. Guidelines for the conduct and reporting of crossover trials might improve the conduct and reporting of studies using this important trial design. PMID:19405975

  16. A matched crossover design for clinical trials.

    PubMed

    Simon, Laura J; Chinchilli, Vernon M

    2007-09-01

    Two design principles are used frequently in clinical trials: 1) A subject is "matched" or "paired" with a similar subject to reduce the chance that other variables obscure the primary comparison of interest. 2) A subject serves as his/her own control by "crossing over" from one treatment to another during the course of an experiment. There are situations in which it may be advantageous to use the two design principles - crossing over and matching - simultaneously. That is, it may be advantageous to conduct a "paired crossover design," in which each subject, while paired with a similar subject, crosses over and receives each experimental treatment. In this paper, we describe two clinical trials conducted by the National Heart, Lung and Blood Institute's Asthma Clinical Research Network that used a paired 2x2 crossover design. The Beta Adrenergic Response by GEnotype (BARGE) Study compared the effects of regular use of inhaled albuterol on mildly asthmatic patients with different genotypes at the 16th position of the beta-agonist receptor gene. The Smoking Modulates Outcomes of Glucocorticoid (SMOG) Therapy in Asthma Study evaluated the hypothesis that smoking reduces the response to inhaled corticosteroids. For such paired crossover designs, the primary parameter of interest is typically the treatment-by-pairing interaction term. In evaluating the relative efficiency of the paired 2x2 crossover design to two independent crossover designs with respect to this interaction term, we show that the paired 2x2 crossover design is more efficient if the correlations between the paired members on the same treatments are greater than their correlations on different treatments. This condition should hold in most circumstances, and therefore the paired crossover design deserves serious consideration for any clinical trial in which the crossing over and matching of subjects is deemed simultaneously beneficial.

  17. Fermionic full counting statistics with smooth boundaries: From discrete particles to bosonization

    NASA Astrophysics Data System (ADS)

    Ivanov, Dmitri A.; Levkivskyi, Ivan P.

    2016-01-01

    We revisit the problem of full counting statistics of particles on a segment of a one-dimensional gas of free fermions. Using a combination of analytical and numerical methods, we study the crossover between the counting of discrete particles and of the continuous particle density as a function of smoothing in the counting procedure. In the discrete-particle limit, the result is given by the Fisher-Hartwig expansion for Toeplitz determinants, while in the continuous limit we recover the bosonization results. This example of full counting statistics with smoothing is also related to orthogonality catastrophe, Fermi-edge singularity and non-equilibrium bosonization.

  18. Averaging of TNTC counts.

    PubMed Central

    Haas, C N; Heller, B

    1988-01-01

    When plate count methods are used for microbial enumeration, if too-numerous-to-count results occur, they are commonly discarded. In this paper, a method for consideration of such results in computation of an average microbial density is developed, and its use is illustrated by example. PMID:3178211

  19. Anarthria impairs subvocal counting.

    PubMed

    Cubelli, R; Nichelli, P; Pentore, R

    1993-12-01

    We studied subvocal counting in two pure anarthric patients. Analysis showed that they performed definitively worse than normal subjects free to articulate subvocally and their scores were in the lower bounds of the performances of subjects suppressing articulation. These results suggest that subvocal counting is impaired after anarthria.

  20. Complexities of Counting.

    ERIC Educational Resources Information Center

    Stake, Bernadine Evans

    This document focuses on one child's skip counting methods. The pupil, a second grade student at Steuben School, in Kankakee, Illinois, was interviewed as she made several attempts at counting twenty-five poker chips on a circular piece of paper. The interview was part of a larger study of "Children's Conceptions of Number and Numeral,"…

  1. Counting Sheep in Basque

    ERIC Educational Resources Information Center

    Araujo, Frank P.

    1975-01-01

    Demonstrates the interplay of a cognitive system, the Basque numerative system, and a behavioral one, counting sheep. The significant features of the Basque numerative system are analyzed; then it is shown how use of these features facilitates the counting of sheep on open ranges by Basque sheep farmers in California. (Author/RM)

  2. Spin-crossover molecule based thermoelectric junction

    SciTech Connect

    Ghosh, Dibyajyoti; Parida, Prakash; Pati, Swapan K.

    2015-05-11

    Using ab-initio numerical methods, we explore the spin-dependent transport and thermoelectric properties of a spin-crossover molecule (i.e., iron complex of 2-(1H-pyrazol-1-yl)-6-(1H-tetrazole-5-yl)pyridine) based nano-junction. We demonstrate a large magnetoresistance, efficient conductance-switching, and spin-filter activity in this molecule-based two-terminal device. The spin-crossover process also modulates the thermoelectric entities. It can efficiently switch the magnitude as well as spin-polarization of the thermocurrent. We find that thermocurrent is changed by ∼4 orders of magnitude upon spin-crossover. Moreover, it also substantially affects the thermopower and consequently, the device shows extremely efficient spin-crossover magnetothermopower generation. Furthermore, by tuning the chemical potential of electrodes into a certain range, a pure spin-thermopower can be achieved for the high-spin state. Finally, the reasonably large values of figure-of-merit in the presence and absence of phonon demonstrate a large heat-to-voltage conversion efficiency of the device. We believe that our study will pave an alternative way of tuning the transport and thermoelectric properties through the spin-crossover process and can have potential applications in generation of spin-dependent current, information storage, and processing.

  3. Multiferroic crossover in perovskite oxides

    NASA Astrophysics Data System (ADS)

    Weston, L.; Cui, X. Y.; Ringer, S. P.; Stampfl, C.

    2016-04-01

    drives the ferroelectric state (Kv). The recovery of the lattice instability for high-spin d5-d7 and d8 cations is due to (i) a reduction in K0 due to a significant volume increase arising from population of the σ -bonded axial d eg orbitals, and (ii) an increase in the Kv contribution arising from increased p -d hybridization; our calculations suggest that the former mechanism is dominant. Surprisingly, we are able to show that, in some cases unpaired electron spins actually drive ferroelectricity, rather than inhibit it, which represents a shift in the understanding of how ferroelectricity and magnetism interact in perovskite oxides. It follows, that for the case of BiCoO3, the Co3 + ion plays a major role in the ferroelectric lattice instability. Importantly, the ferroelectric polarization is greatly enhanced when the Co3 + ion is in the high-spin state, when compared to the nonmagnetic, low-spin state, and a large coupling of the electric and magnetic polarization is present. Generally, for d5-d7 B cations in A B O3 perovskites, an inherent and remarkably strong magnetoelectric coupling exists via the multiferroic crossover effect, whereby switching the spin state strongly affects the ferroelectric polarization and, potentially, manipulation of the polarization with an externally applied electric field could induce a spin-state transition. This novel effect is demonstrated for BiCoO3, for which the ground spin state is switched by reducing the internal ferroelectric polarization. These results provide a deeper insight into perovskite ferroelectrics and multiferroics.

  4. AUTOMATIC COUNTING APPARATUS

    DOEpatents

    Howell, W.D.

    1957-08-20

    An apparatus for automatically recording the results of counting operations on trains of electrical pulses is described. The disadvantages of prior devices utilizing the two common methods of obtaining the count rate are overcome by this apparatus; in the case of time controlled operation, the disclosed system automatically records amy information stored by the scaler but not transferred to the printer at the end of the predetermined time controlled operations and, in the case of count controlled operation, provision is made to prevent a weak sample from occupying the apparatus for an excessively long period of time.

  5. Understanding Blood Counts

    MedlinePlus

    ... Heart, Kidneys, Liver and Lung Function Infections Iron Overload Low Blood Counts Pain Disease- and Treatment-Related ... cancer research around the world and provides free information and support services. Privacy Policy Security Copyright Link ...

  6. Blood Count Tests

    MedlinePlus

    ... white blood cells (WBC), and platelets. Blood count tests measure the number and types of cells in ... helps doctors check on your overall health. The tests can also help to diagnose diseases and conditions ...

  7. Calorie count - Fast food

    MedlinePlus

    ... count - fast food FOOD ITEM SERVING SIZE CALORIES Breakfast Foods Dunkin Donuts Egg White Veggie Wrap 1 ... Cheese Biscuit Sandwich 1 sandwich 510 BK Ultimate Breakfast Platter 1 platter 1190 McDonalds Fruit 'n Yogurt ...

  8. Carbohydrate Counting and Diabetes

    MedlinePlus

    ... are the other main nutrients. Carbohydrates include sugars, starches, and fiber. Carbohydrate counting can help you control ... called starchy vegetables because they are high in starch. These vegetables have more carbohydrates per serving than ...

  9. Inventory count strategies.

    PubMed

    Springer, W H

    1996-02-01

    An important principle of accounting is that asset inventory needs to be correctly valued to ensure that the financial statements of the institution are accurate. Errors is recording the value of ending inventory in one fiscal year result in errors to published financial statements for that year as well as the subsequent fiscal year. Therefore, it is important that accurate physical counts be periodically taken. It is equally important that any system being used to generate inventory valuation, reordering or management reports be based on consistently accurate on-hand balances. At the foundation of conducting an accurate physical count of an inventory is a comprehensive understanding of the process coupled with a written plan. This article presents a guideline of the physical count processes involved in a traditional double-count approach.

  10. Crossover from incoherent to coherent phonon scattering in epitaxial oxide superlattices

    NASA Astrophysics Data System (ADS)

    Ravichandran, Jayakanth; Yadav, Ajay K.; Cheaito, Ramez; Rossen, Pim B.; Soukiassian, Arsen; Suresha, S. J.; Duda, John C.; Foley, Brian M.; Lee, Che-Hui; Zhu, Ye; Lichtenberger, Arthur W.; Moore, Joel E.; Muller, David A.; Schlom, Darrell G.; Hopkins, Patrick E.; Majumdar, Arun; Ramesh, Ramamoorthy; Zurbuchen, Mark A.

    2014-02-01

    Elementary particles such as electrons or photons are frequent subjects of wave-nature-driven investigations, unlike collective excitations such as phonons. The demonstration of wave-particle crossover, in terms of macroscopic properties, is crucial to the understanding and application of the wave behaviour of matter. We present an unambiguous demonstration of the theoretically predicted crossover from diffuse (particle-like) to specular (wave-like) phonon scattering in epitaxial oxide superlattices, manifested by a minimum in lattice thermal conductivity as a function of interface density. We do so by synthesizing superlattices of electrically insulating perovskite oxides and systematically varying the interface density, with unit-cell precision, using two different epitaxial-growth techniques. These observations open up opportunities for studies on the wave nature of phonons, particularly phonon interference effects, using oxide superlattices as model systems, with extensive applications in thermoelectrics and thermal management.

  11. Crossover from incoherent to coherent phonon scattering in epitaxial oxide superlattices.

    PubMed

    Ravichandran, Jayakanth; Yadav, Ajay K; Cheaito, Ramez; Rossen, Pim B; Soukiassian, Arsen; Suresha, S J; Duda, John C; Foley, Brian M; Lee, Che-Hui; Zhu, Ye; Lichtenberger, Arthur W; Moore, Joel E; Muller, David A; Schlom, Darrell G; Hopkins, Patrick E; Majumdar, Arun; Ramesh, Ramamoorthy; Zurbuchen, Mark A

    2014-02-01

    Elementary particles such as electrons or photons are frequent subjects of wave-nature-driven investigations, unlike collective excitations such as phonons. The demonstration of wave-particle crossover, in terms of macroscopic properties, is crucial to the understanding and application of the wave behaviour of matter. We present an unambiguous demonstration of the theoretically predicted crossover from diffuse (particle-like) to specular (wave-like) phonon scattering in epitaxial oxide superlattices, manifested by a minimum in lattice thermal conductivity as a function of interface density. We do so by synthesizing superlattices of electrically insulating perovskite oxides and systematically varying the interface density, with unit-cell precision, using two different epitaxial-growth techniques. These observations open up opportunities for studies on the wave nature of phonons, particularly phonon interference effects, using oxide superlattices as model systems, with extensive applications in thermoelectrics and thermal management.

  12. Neutron counting with cameras

    SciTech Connect

    Van Esch, Patrick; Crisanti, Marta; Mutti, Paolo

    2015-07-01

    A research project is presented in which we aim at counting individual neutrons with CCD-like cameras. We explore theoretically a technique that allows us to use imaging detectors as counting detectors at lower counting rates, and transits smoothly to continuous imaging at higher counting rates. As such, the hope is to combine the good background rejection properties of standard neutron counting detectors with the absence of dead time of integrating neutron imaging cameras as well as their very good spatial resolution. Compared to Xray detection, the essence of thermal neutron detection is the nuclear conversion reaction. The released energies involved are of the order of a few MeV, while X-ray detection releases energies of the order of the photon energy, which is in the 10 KeV range. Thanks to advances in camera technology which have resulted in increased quantum efficiency, lower noise, as well as increased frame rate up to 100 fps for CMOS-type cameras, this more than 100-fold higher available detection energy implies that the individual neutron detection light signal can be significantly above the noise level, as such allowing for discrimination and individual counting, which is hard to achieve with X-rays. The time scale of CMOS-type cameras doesn't allow one to consider time-of-flight measurements, but kinetic experiments in the 10 ms range are possible. The theory is next confronted to the first experimental results. (authors)

  13. The Design of Cluster Randomized Crossover Trials

    ERIC Educational Resources Information Center

    Rietbergen, Charlotte; Moerbeek, Mirjam

    2011-01-01

    The inefficiency induced by between-cluster variation in cluster randomized (CR) trials can be reduced by implementing a crossover (CO) design. In a simple CO trial, each subject receives each treatment in random order. A powerful characteristic of this design is that each subject serves as its own control. In a CR CO trial, clusters of subjects…

  14. Cedarwood: cross-over pressure research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of experiments were conducted to determine the cross-over pressure for cedarwood oil in carbon dioxide. A closed stirrer reactor with an in-line loop connected to the injector of a GC was used to measure the concentration of cedarwood oil in the carbon dioxide. Both neat cedarwood oil as ...

  15. Critical Crossover Functions for Simple Fluids: Towards the Crossover Modelling Uniqueness

    NASA Astrophysics Data System (ADS)

    Garrabos, Yves; Lecoutre, Carole; Marre, Samuel; LeNeindre, Bernard; Hahn, Inseob

    2016-11-01

    Based on a single non-universal temperature scaling factor present in a simple fluid case, a detailed analysis of non-universal parameters involved in different critical-to-classical crossover models is given. For the infinite limit of the cutoff wave number, a set of three scaling-parameters is defined for each model such that it shows all the shapes of the theoretical crossover functions overlap on the mean crossover function shapes close to the non-trivial fixed point. The analysis of corresponding links between their fluid-dependent parameters opens a route to define a parametric model of crossover equation-of-state, closely satisfying the universal features calculated from the Ising-like limit in the massive renormalization scheme.

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

    PubMed

    Janesick, James; Tower, John

    2016-05-12

    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.

  17. Fast counting electronics for neutron coincidence counting

    DOEpatents

    Swansen, James E.

    1987-01-01

    An amplifier-discriminator is tailored to output a very short pulse upon an above-threshold input from a detector which may be a .sup.3 He detector. The short pulse output is stretched and energizes a light emitting diode (LED) to provide a visual output of operation and pulse detection. The short pulse is further fed to a digital section for processing and possible ORing with other like generated pulses. Finally, the output (or ORed output ) is fed to a derandomizing buffer which converts the rapidly and randomly occurring pulses into synchronized and periodically spaced-apart pulses for the accurate counting thereof. Provision is also made for the internal and external disabling of each individual channel of amplifier-discriminators in an ORed plurality of same.

  18. Fast counting electronics for neutron coincidence counting

    DOEpatents

    Swansen, J.E.

    1985-03-05

    An amplifier-discriminator is tailored to output a very short pulse upon an above-threshold input from a detector which may be a /sup 3/He detector. The short pulse output is stretched and energizes a light emitting diode (LED) to provide a visual output of operation and pulse detection. The short pulse is further fed to a digital section for processing and possible ORing with other like generated pulses. Finally, the output (or ORed output) is fed to a derandomizing buffer which converts the rapidly and randomly occurring pulses into synchronized and periodically spaced-apart pulses for the accurate counting thereof. Provision is also made for the internal and external disabling of each individual channel of amplifier-discriminators in an ORed plurality of same.

  19. Interferences in Immunoassay

    PubMed Central

    Tate, Jill; Ward, Greg

    2004-01-01

    Substances that alter the measurable concentration of the analyte or alter antibody binding can potentially result in immunoassay interference. Interfering, endogenous substances that are natural, polyreactive antibodies or autoantibodies (heterophiles), or human anti-animal antibodies together with other unsuspected binding proteins that are unique to the individual, can interfere with the reaction between analyte and reagent antibodies in immunoassay. Lipaemia, cross-reactivity, and exogenous interferences due to pre-analytical variation, matrix and equipment reaction also affect immunoassay. Interfering substances may lead to falsely elevated or falsely low analyte concentration in one or more assay systems depending on the site of the interference in the reaction and possibly result in discordant results for other analytes. The prevalence of interference is generally low in assays containing blocking agents that neutralise or inhibit the interference but is often higher in new, untested immunoassays. A wide range of analytes measured by immunoassay including hormones, tumour markers, drugs, cardiac troponin and microbial serology may be affected. Interference in immunoassay may lead to the misinterpretation of a patient's results by the laboratory and the wrong course of treatment being given by the physician. Laboratories should put processes in place to detect, test and report suspected interferences. It is equally important that physicians communicate any clinical suspicion of discordance between the clinical and the laboratory data to the laboratory. The detection of interference may require the use of an alternate assay or additional measurements, before and after treatment with additional blocking reagent, or following dilution of the sample in non-immune serum. It is imperative that laboratories inform physicians of the follow-up procedure and report on the presence of any interference. The establishment of on-going laboratory-physician contact is

  20. Interpretation of galaxy counts

    SciTech Connect

    Tinsely, B.M.

    1980-10-01

    New models are presented for the interpretation of recent counts of galaxies to 24th magnitude, and predictions are shown to 28th magnitude for future comparison with data from the Space Telescope. The results supersede earlier, more schematic models by the author. Tyson and Jarvis found in their counts a ''local'' density enhancement at 17th magnitude, on comparison with the earlier models; the excess is no longer significant when a more realistic mixture of galaxy colors is used. Bruzual and Kron's conclusion that Kron's counts show evidence for evolution at faint magnitudes is confirmed, and it is predicted that some 23d magnitude galaxies have redshifts greater than unity. These may include spheroidal systems, elliptical galaxies, and the bulges of early-type spirals and S0's, seen during their primeval rapid star formation.

  1. Whose interests count?

    PubMed

    Brudney, Daniel; Lantos, John D

    2014-10-01

    Whose interests should count and how should various interests be balanced at the pediatric patient's bedside? The interests of the child patient clearly count. Recently, however, many authors have argued that the family's interests also count. But how should we think about the interests of others? What does it mean to talk about "the family" in this context? Does it really just mean the interests of each individual family member? Or is the family itself a moral entity that has interests of its own independent of the interests of each of its members? Are such interests important only as they affect the patient's interest or also for their own sake? In this special supplement to Pediatrics, a group of pediatricians, philosophers, and lawyers grapple with these questions. They examine these issues from different angles and reach different conclusions. Jointly, they demonstrate the ethical importance and, above all, the ethical complexity of the family's role at the bedside.

  2. Crossover by Line Length and Spatial Location

    PubMed Central

    Mennemeier, Mark; Rapcsak, Steven Z.; Pierce, Chris; Vezey, Elsie

    2015-01-01

    It is well known that line length has a systematic influence on line bisection error in neglect. Most patients with neglect misbisect long lines on the same side of true center as their brain lesion but then cross over on short lines, misbisecting them on the opposite side (i.e., crossover by line length). What is less recognized is that the spatial location of lines relative to the viewer can similarly induce a crossover effect when one considers line bisection error scores that have been averaged across individual line lengths. Patients with right hemisphere injury and neglect classically make averaged line bisection errors that fall right of true center on lines located either at midline or to the left of the viewer; however, we observed that the averaged line bisection error can fall left of true center when lines are located to the right of the viewer (i.e., crossover by spatial location). We hypothesized that crossover by both line length and spatial location stem from systematic errors in magnitude estimation, i.e., perceived line length. We tested predictions based on this hypothesis by examining how the crossover effect by line length is altered by the spatial location of lines along a horizontal axis relative to the viewer. Participants included patients with unilateral lesions of the right and left cerebral hemispheres and age-appropriate normal subjects. All groups demonstrated a crossover effect by line length at the midline location but the effect was altered by placing lines to the right and left of the viewer. In particular, patients with right hemisphere injury and neglect crossed-over across a hroader range of line lengths when the lines were located to the right of the viewer rather than at either midline or left of the viewer. It is proposed that mental representations of stimulus magnitude are altered in neglect, in addition to mental representations of space, and that traditional accounts of neglect can be enhanced by including the

  3. Thick Film Interference.

    ERIC Educational Resources Information Center

    Trefil, James

    1983-01-01

    Discusses why interference effects cannot be seen with a thick film, starting with a review of the origin of interference patterns in thin films. Considers properties of materials in films, properties of the light source, and the nature of light. (JN)

  4. Suppression of Biodynamic Interference by Adaptive Filtering

    NASA Technical Reports Server (NTRS)

    Velger, M.; Merhav, S. J.; Grunwald, A. J.

    1984-01-01

    Preliminary experimental results obtained in moving base simulator tests are presented. Both for pursuit and compensatory tracking tasks, a strong deterioration in tracking performance due to biodynamic interference is found. The use of adaptive filtering is shown to substantially alleviate these effects, resulting in a markedly improved tracking performance and reduction in task difficulty. The effect of simulator motion and of adaptive filtering on human operator describing functions is investigated. Adaptive filtering is found to substantially increase pilot gain and cross-over frequency, implying a more tight tracking behavior. The adaptive filter is found to be effective in particular for high-gain proportional dynamics, low display forcing function power and for pursuit tracking task configurations.

  5. Interference laser processing

    NASA Astrophysics Data System (ADS)

    Nakata, Yoshiki

    2016-02-01

    The most important component of quantum optics is laser interference. Interference patterns are formed by splitting a coherent beam into multiple beams and correlating them. This study introduces a variety of beam correlators and discusses their characteristics. Beam correlator basics such as interference region in terms of pulse width, group delay dispersion effects on pulse width, optical delay adjustment, and interference pattern simulation are explained. A discussion of the history of interference processing begins with the method in 1967 and continues through the advancement of shorter wavelengths and pulse widths. The recent techniques of solid-liquid-solid for 3D nanofabrication, duplicated structures with laser-induced periodic surface structure, processing inside transparent materials, and 2D and 3D periodic structures fabricated by photo-sensitization are also presented.

  6. LOW ENERGY COUNTING CHAMBERS

    DOEpatents

    Hayes, P.M.

    1960-02-16

    A beta particle counter adapted to use an end window made of polyethylene terephthalate was designed. The extreme thinness of the film results in a correspondingly high transmission of incident low-energy beta particles by the window. As a consequence, the counting efficiency of the present counter is over 40% greater than counters using conventional mica end windows.

  7. WY Kids Count.

    ERIC Educational Resources Information Center

    Wyoming Kids Count, Cheyenne.

    This WY Kids Count brochure uses the metaphor of children's building blocks to present information on the current well-being of Wyoming children and to advocate enhancing the lives of young children. Each block (i.e., each develop the brochure) presents concerns in a separate area: (1) poverty, highlighting the number of children living in…

  8. What Counts as Evidence?

    ERIC Educational Resources Information Center

    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…

  9. Exchangeability in the case-crossover design.

    PubMed

    Mittleman, Murray A; Mostofsky, Elizabeth

    2014-10-01

    In cohort and case-control studies, confounding that arises as a result of differences in the distribution of determinants of the outcome between exposure groups leading to non-exchangeability are addressed by restriction, matching or with statistical models. In case-only studies, this issue is addressed by comparing each individual with his/herself. Although case-only designs use self-matching and only include individuals who develop the outcome of interest, issues of non-exchangeability are identical to those that arise in traditional case-control and cohort studies. In this review, we describe one type of case-only design, the case-crossover design, and discuss how the concept of exchangeability can be used to understand issues of confounding, carryover effects, period effects and selection bias in case-crossover studies.

  10. Dimensional crossover in dipolar magnetic layers

    NASA Astrophysics Data System (ADS)

    Bulenda, M.; Täuber, U. C.; Schwabl, F.

    2000-01-01

    We investigate the static critical behaviour of a uniaxial magnetic layer, with finite thickness L in one direction, yet infinitely extended in the remaining d dimensions. The magnetic dipole-dipole interaction is taken into account. We apply a variant of Wilson's momentum shell renormalization group approach to describe the crossover between the critical behaviour of the 3D Ising, 2D Ising, 3D uniaxial dipolar, and the 2D uniaxial dipolar universality classes. The corresponding renormalization group fixed points are in addition to different effective dimensionalities characterized by distinct analytic structures of the propagator, and are consequently associated with varying upper critical dimensions. While the limiting cases can be discussed by means of dimensional icons/Journals/Common/epsilon" ALT="epsilon" ALIGN="TOP"/> expansions with respect to the appropriate upper critical dimensions, respectively, the crossover features must be addressed in terms of the renormalization group flow trajectories at fixed dimensionality d .

  11. JavaGenes: Evolving Graphs with Crossover

    NASA Technical Reports Server (NTRS)

    Globus, Al; Atsatt, Sean; Lawton, John; Wipke, Todd

    2000-01-01

    Genetic algorithms usually use string or tree representations. We have developed a novel crossover operator for a directed and undirected graph representation, and used this operator to evolve molecules and circuits. Unlike strings or trees, a single point in the representation cannot divide every possible graph into two parts, because graphs may contain cycles. Thus, the crossover operator is non-trivial. A steady-state, tournament selection genetic algorithm code (JavaGenes) was written to implement and test the graph crossover operator. All runs were executed by cycle-scavagging on networked workstations using the Condor batch processing system. The JavaGenes code has evolved pharmaceutical drug molecules and simple digital circuits. Results to date suggest that JavaGenes can evolve moderate sized drug molecules and very small circuits in reasonable time. The algorithm has greater difficulty with somewhat larger circuits, suggesting that directed graphs (circuits) are more difficult to evolve than undirected graphs (molecules), although necessary differences in the crossover operator may also explain the results. In principle, JavaGenes should be able to evolve other graph-representable systems, such as transportation networks, metabolic pathways, and computer networks. However, large graphs evolve significantly slower than smaller graphs, presumably because the space-of-all-graphs explodes combinatorially with graph size. Since the representation strongly affects genetic algorithm performance, adding graphs to the evolutionary programmer's bag-of-tricks should be beneficial. Also, since graph evolution operates directly on the phenotype, the genotype-phenotype translation step, common in genetic algorithm work, is eliminated.

  12. Quantum-classical crossover in electrodynamics

    SciTech Connect

    Polonyi, Janos

    2006-09-15

    A classical field theory is proposed for the electric current and the electromagnetic field interpolating between microscopic and macroscopic domains. It represents a generalization of the density functional for the dynamics of the current and the electromagnetic field in the quantum side of the crossover and reproduces standard classical electrodynamics on the other side. The effective action derived in the closed time path formalism and the equations of motion follow from the variational principle. The polarization of the Dirac-sea can be taken into account in the quadratic approximation of the action by the introduction of the deplacement field strengths as in conventional classical electrodynamics. Decoherence appears naturally as a simple one-loop effect in this formalism. It is argued that the radiation time arrow is generated from the quantum boundary conditions in time by decoherence at the quantum-classical crossover and the Abraham-Lorentz force arises from the accelerating charge or from other charges in the macroscopic or the microscopic side, respectively. The functional form of the quantum renormalization group, the generalization of the renormalization group method for the density matrix, is proposed to follow the scale dependence through the quantum-classical crossover in a systematical manner.

  13. Geosat crossover analysis in the tropical Pacific. Part 1: Constrained sinusoidal crossover adjustment

    NASA Technical Reports Server (NTRS)

    Tai, Chang-Kou

    1988-01-01

    A new method (constrained sinusoidal crossover adjustment) for removing the orbit error in satellite altimetry is tested (using crossovers accumulated in the first 91 days of the Geosat non-repeat era in the tropical Pacific) and found to have excellent qualities. Two features distinguish the new method from the conventional bias-and-tilt crossover adjustment. First, a sine wave (with wavelength equaling the circumference of the Earth) is used to represent the orbit error for each satellite revolution, instead of the bias-and-tilt (and curvature, if necessary) approach for each segment of the satellite ground track. Secondly, the indeterminacy of the adjustment process is removed by a simple constraint minimizing the amplitudes of the sine waves, rather than by fixing selected tracks. Overall the new method is more accurate, more efficient, and much less cumbersome than the old. The idea of restricting the crossover adjustment to crossovers between tracks that are less than certain days apart in order to preserve the large-scale long-term oceanic variability is also tested with inconclusive results because the orbit error was unusually nonstationary in the initial 91 days of the GEOSAT mission.

  14. A new crossover operator in genetic programming for object classification.

    PubMed

    Zhang, Mengjie; Gao, Xiaoying; Lou, Weijun

    2007-10-01

    The crossover operator has been considered "the centre of the storm" in genetic programming (GP). However, many existing GP approaches to object recognition suggest that the standard GP crossover is not sufficiently powerful in producing good child programs due to the totally random choice of the crossover points. To deal with this problem, this paper introduces an approach with a new crossover operator in GP for object recognition, particularly object classification. In this approach, a local hill-climbing search is used in constructing good building blocks, a weight called looseness is introduced to identify the good building blocks in individual programs, and the looseness values are used as heuristics in choosing appropriate crossover points to preserve good building blocks. This approach is examined and compared with the standard crossover operator and the headless chicken crossover (HCC) method on a sequence of object classification problems. The results suggest that this approach outperforms the HCC, the standard crossover, and the standard crossover operator with hill climbing on all of these problems in terms of the classification accuracy. Although this approach spends a bit longer time than the standard crossover operator, it significantly improves the system efficiency over the HCC method.

  15. The Watt Count System

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The Watt Count System combines aerospace and computer technology, an engineering systems design approach and the environmental control expertise of a group of engineers who worked on Apollo. First step of the system is a computerized energy consumption analysis based on plans for a new home. Company calculates heating and cooling loads and customizes the most energy efficient system for the particular structure analyzed. A quality control engineer assures that insulation and ducting are installed to specifications. Analysis and design techniques are so accurate that company is able to give homeowner a two-year guarantee that the home's energy consumption will not exceed the kilowatt hour level determined by the computer in step one. In an annual energy performance comparison, a Watt Count home used 45 percent less energy than a conventionally equipped home.

  16. Plasmonic optical interference.

    PubMed

    Choi, Dukhyun; Shin, Chang Kyun; Yoon, Daesung; Chung, Deuk Seok; Jin, Yong Wan; Lee, Luke P

    2014-06-11

    Understanding optical interference is of great importance in fundamental and analytical optical design for next-generation personal, industrial, and military applications. So far, various researches have been performed for optical interference phenomena, but there have been no reports on plasmonic optical interference. Here, we report that optical interference could be effectively coupled with surface plasmons, resulting in enhanced optical absorption. We prepared a three-dimensional (3D) plasmonic nanostructure that consists of a plasmonic layer at the top, a nanoporous dielectric layer at the center, and a mirror layer at the bottom. The plasmonic layer mediates strong plasmonic absorption when the constructive interference pattern is matched with the plasmonic component. By tailoring the thickness of the dielectric layer, the strong plasmonic absorption can facilely be controlled and covers the full visible range. The plasmonic interference in the 3D nanostructure thus creates brilliant structural colors. We develop a design equation to determine the thickness of the dielectric layer in a 3D plasmonic nanostructure that could create the maximum absorption at a given wavelength. It is further demonstrated that the 3D plasmonic nanostructure can be realized on a flexible substrate. Our 3D plasmonic nanostructures will have a huge impact on the fields of optoelectronic systems, biochemical optical sensors, and spectral imaging.

  17. Shocks generate crossover behavior in lattice avalanches.

    PubMed

    Burridge, James

    2013-11-22

    A spatial avalanche model is introduced, in which avalanches increase stability in the regions where they occur. Instability is driven globally by a driving process that contains shocks. The system is typically subcritical, but the shocks occasionally lift it into a near- or supercritical state from which it rapidly retreats due to large avalanches. These shocks leave behind a signature-a distinct power-law crossover in the avalanche size distribution. The model is inspired by landslide field data, but the principles may be applied to any system that experiences stabilizing failures, possesses a critical point, and is subject to an ongoing process of destabilization that includes occasional dramatic destabilizing events.

  18. High Red Blood Cell Count

    MedlinePlus

    Symptoms High red blood cell count By Mayo Clinic Staff A high red blood cell count is an increase in oxygen-carrying cells in your bloodstream. Red blood cells transport oxygen from your lungs to tissues throughout ...

  19. Counting RG flows

    SciTech Connect

    Gukov, Sergei

    2016-01-05

    Here, 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.

  20. Counting RG flows

    DOE PAGES

    Gukov, Sergei

    2016-01-05

    Here, 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 powerfulmore » 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.« less

  1. Neural networks counting chimes.

    PubMed Central

    Amit, D J

    1988-01-01

    It is shown that the ideas that led to neural networks capable of recalling associatively and asynchronously temporal sequences of patterns can be extended to produce a neural network that automatically counts the cardinal number in a sequence of identical external stimuli. The network is explicitly constructed, analyzed, and simulated. Such a network may account for the cognitive effect of the automatic counting of chimes to tell the hour. A more general implication is that different electrophysiological responses to identical stimuli, at certain stages of cortical processing, do not necessarily imply synaptic modification, a la Hebb. Such differences may arise from the fact that consecutive identical inputs find the network in different stages of an active temporal sequence of cognitive states. These types of networks are then situated within a program for the study of cognition, which assigns the detection of meaning as the primary role of attractor neural networks rather than computation, in contrast to the parallel distributed processing attitude to the connectionist project. This interpretation is free of homunculus, as well as from the criticism raised against the cognitive model of symbol manipulation. Computation is then identified as the syntax of temporal sequences of quasi-attractors. PMID:3353371

  2. Localization of Interference Fringes.

    ERIC Educational Resources Information Center

    Simon, J. M.; Comastri, Silvia A.

    1980-01-01

    Discusses a proof for determining the localized fringes position arrived at when one considers the interference of two extended sources when one is able to observe fringes only at certain points in space. Shows how the localized fringes may be found in a device used to observe Newton's rings. (Author/CS)

  3. Interference and Sensitivity Analysis

    PubMed Central

    VanderWeele, Tyler J.; Tchetgen Tchetgen, Eric J.; Halloran, M. Elizabeth

    2014-01-01

    Causal inference with interference is a rapidly growing area. The literature has begun to relax the “no-interference” assumption that the treatment received by one individual does not affect the outcomes of other individuals. In this paper we briefly review the literature on causal inference in the presence of interference when treatments have been randomized. We then consider settings in which causal effects in the presence of interference are not identified, either because randomization alone does not suffice for identification, or because treatment is not randomized and there may be unmeasured confounders of the treatment-outcome relationship. We develop sensitivity analysis techniques for these settings. We describe several sensitivity analysis techniques for the infectiousness effect which, in a vaccine trial, captures the effect of the vaccine of one person on protecting a second person from infection even if the first is infected. We also develop two sensitivity analysis techniques for causal effects in the presence of unmeasured confounding which generalize analogous techniques when interference is absent. These two techniques for unmeasured confounding are compared and contrasted. PMID:25620841

  4. Quantum interference in polyenes

    NASA Astrophysics Data System (ADS)

    Tsuji, Yuta; Hoffmann, Roald; Movassagh, Ramis; Datta, Supriyo

    2014-12-01

    The explicit form of the zeroth Green's function in the Hückel model, approximated by the negative of the inverse of the Hückel matrix, has direct quantum interference consequences for molecular conductance. We derive a set of rules for transmission between two electrodes attached to a polyene, when the molecule is extended by an even number of carbons at either end (transmission unchanged) or by an odd number of carbons at both ends (transmission turned on or annihilated). These prescriptions for the occurrence of quantum interference lead to an unexpected consequence for switches which realize such extension through electrocyclic reactions: for some specific attachment modes the chemically closed ring will be the ON position of the switch. Normally the signs of the entries of the Green's function matrix are assumed to have no physical significance; however, we show that the signs may have observable consequences. In particular, in the case of multiple probe attachments - if coherence in probe connections can be arranged - in some cases new destructive interference results, while in others one may have constructive interference. One such case may already exist in the literature.

  5. Quantum interference in polyenes.

    PubMed

    Tsuji, Yuta; Hoffmann, Roald; Movassagh, Ramis; Datta, Supriyo

    2014-12-14

    The explicit form of the zeroth Green's function in the Hückel model, approximated by the negative of the inverse of the Hückel matrix, has direct quantum interference consequences for molecular conductance. We derive a set of rules for transmission between two electrodes attached to a polyene, when the molecule is extended by an even number of carbons at either end (transmission unchanged) or by an odd number of carbons at both ends (transmission turned on or annihilated). These prescriptions for the occurrence of quantum interference lead to an unexpected consequence for switches which realize such extension through electrocyclic reactions: for some specific attachment modes the chemically closed ring will be the ON position of the switch. Normally the signs of the entries of the Green's function matrix are assumed to have no physical significance; however, we show that the signs may have observable consequences. In particular, in the case of multiple probe attachments - if coherence in probe connections can be arranged - in some cases new destructive interference results, while in others one may have constructive interference. One such case may already exist in the literature.

  6. Quantum interference in polyenes

    SciTech Connect

    Tsuji, Yuta; Hoffmann, Roald; Movassagh, Ramis; Datta, Supriyo

    2014-12-14

    The explicit form of the zeroth Green's function in the Hückel model, approximated by the negative of the inverse of the Hückel matrix, has direct quantum interference consequences for molecular conductance. We derive a set of rules for transmission between two electrodes attached to a polyene, when the molecule is extended by an even number of carbons at either end (transmission unchanged) or by an odd number of carbons at both ends (transmission turned on or annihilated). These prescriptions for the occurrence of quantum interference lead to an unexpected consequence for switches which realize such extension through electrocyclic reactions: for some specific attachment modes the chemically closed ring will be the ON position of the switch. Normally the signs of the entries of the Green's function matrix are assumed to have no physical significance; however, we show that the signs may have observable consequences. In particular, in the case of multiple probe attachments – if coherence in probe connections can be arranged – in some cases new destructive interference results, while in others one may have constructive interference. One such case may already exist in the literature.

  7. Electromagnetic pump stator frame having power crossover struts

    DOEpatents

    Fanning, Alan W.; Olich, Eugene E.

    1995-01-01

    A stator frame for an electromagnetic pump includes a casing joined to a hub by a plurality of circumferentially spaced apart struts. At least one electrically insulated power crossover lead extends through the hub, through a crossover one of the struts, and through the casing for carrying electrical current therethrough.

  8. Orbital Transfer Rocket Engine Technology High Velocity Ratio Diffusing Crossover

    DTIC Science & Technology

    1992-12-01

    Inducer Tip Seal ......................... 21 Figure 13 - Crossover Tester Thrust Balance Disk...Crossover Tester Rotor Mode Shapes for 500 Kibin ............ ,.....2 9 Figure 18 - Inducer Deflections In Wattr . 0 ’Figure 19 - Impeller Tip...Inducer and Impeller subassembly cantilevered on a shalt supported by two ball bearings. The finite element model of the rotor Is shown in Figure 14

  9. Numerical simulation of bromine crossover behavior in flow battery

    NASA Astrophysics Data System (ADS)

    Jia, Yaobin; Cheng, Shijian; Chu, Dandan; Li, Xin

    2017-03-01

    Br2 and HBr has its own series of advantages as the positive electrolyte solution, so some batteries select the Br2/Br- as the positive electrolyte solution, such as sodium polysulfide/bromine flow battery, zinc/bromine flow battery, vanadium/ bromine flow batteries and hydrogen/bromine flow batteries. But the crossover benavior of bromine occurs in these batteries too, resulting in cross-contamination, capacity loss and affecting battery's performance. In this work, we build numerical models to study the influence of bromine crossover phenomenon on the three forms of bromine crossover, the concentration of electrolyte on the cathode side and the flow rate of the negative side in the quinone bromine flow battery, to find the main models affecting the bromine crossover and the impact of bromine crossover on battery performance. It was found that the three ways of crossover through the membranes was mainly by diffusion. By reducing the concentration of positive electrolyte solution, the bromine crossover can be reduced and Coulomb Efficiency can be improved. Rising the flow rate of the electrolyte solution on the negative side and reducing the differential between positive side's pressure and negative side's pressure can also reduce the amount of bromine crossover to improve Coulomb efficiency in the battery.

  10. A spin crossover ferrous complex with ordered magnetic ferric anions.

    PubMed

    Roubeau, Olivier; Evangelisti, Marco; Natividad, Eva

    2012-08-07

    The first tetrahaloferrate spin crossover compound, [Fe(Metz)(6)](FeBr(4))(2) (Metz = 1-methyltetrazole), is reported. The FeBr(4)(-) ions form ferromagnetically coupled 1D stacks and exhibit an antiferromagnetic order at 2.2 K, which coexists with the gradual spin crossover centred at 165 K.

  11. Research Update: The mechanocaloric potential of spin crossover compounds

    NASA Astrophysics Data System (ADS)

    Sandeman, Karl G.

    2016-11-01

    We present a first evaluation of the potential for spin crossover (SCO) compounds to be considered as a new class of giant mechanocaloric effect materials. From literature data on the variation of the spin crossover temperature with pressure, we estimate the maximum available adiabatic temperature change for several compounds and the relatively low pressures that may be required to observe these effects.

  12. Stress Crossover in Newlywed Marriage: A Longitudinal and Dyadic Perspective

    ERIC Educational Resources Information Center

    Neff, Lisa A.; Karney, Benjamin R.

    2007-01-01

    Studies of stress and marital quality often assess stress as an intrapersonal phenomenon, examining how spouses' stress may influence their own relationship well-being. Yet spouses' stress also may influence partners' relationship evaluations, a phenomenon referred to as stress crossover. This study examined stress crossover, and conditions that…

  13. An efficient algorithm for computing the crossovers in satellite altimetry

    NASA Technical Reports Server (NTRS)

    Tai, Chang-Kou

    1988-01-01

    An efficient algorithm has been devised to compute the crossovers in satellite altimetry. The significance of the crossovers is twofold. First, they are needed to perform the crossover adjustment to remove the orbit error. Secondly, they yield important insight into oceanic variability. Nevertheless, there is no published algorithm to make this very time consuming task easier, which is the goal of this report. The success of the algorithm is predicated on the ability to predict (by analytical means) the crossover coordinates to within 6 km and 1 sec of the true values. Hence, only one interpolation/extrapolation step on the data is needed to derive the crossover coordinates in contrast to the many interpolation/extrapolation operations usually needed to arrive at the same accuracy level if deprived of this information.

  14. Neutrino dynamics below the electroweak crossover

    SciTech Connect

    Ghiglieri, J.; Laine, M.

    2016-07-12

    We estimate the thermal masses and damping rates of active (m< eV) and sterile (M∼ GeV) neutrinos with thermal momenta k∼3T at temperatures below the electroweak crossover (5 GeV 130 GeV remains an option. Our differential rates are tabulated in a form suitable for studies of specific scenarios with given neutrino Yukawa matrices.

  15. Fuel cell membranes and crossover prevention

    DOEpatents

    Masel, Richard I.; York, Cynthia A.; Waszczuk, Piotr; Wieckowski, Andrzej

    2009-08-04

    A membrane electrode assembly for use with a direct organic fuel cell containing a formic acid fuel includes a solid polymer electrolyte having first and second surfaces, an anode on the first surface and a cathode on the second surface and electrically linked to the anode. The solid polymer electrolyte has a thickness t:.gtoreq..times..times..times..times. ##EQU00001## where C.sub.f is the formic acid fuel concentration over the anode, D.sub.f is the effective diffusivity of the fuel in the solid polymer electrolyte, K.sub.f is the equilibrium constant for partition coefficient for the fuel into the solid polymer electrolyte membrane, I is Faraday's constant n.sub.f is the number of electrons released when 1 molecule of the fuel is oxidized, and j.sub.f.sup.c is an empirically determined crossover rate of fuel above which the fuel cell does not operate.

  16. Phosphorylation of the Synaptonemal Complex Protein Zip1 Regulates the Crossover/Noncrossover Decision during Yeast Meiosis.

    PubMed

    Chen, Xiangyu; Suhandynata, Ray T; Sandhu, Rima; Rockmill, Beth; Mohibullah, Neeman; Niu, Hengyao; Liang, Jason; Lo, Hsiao-Chi; Miller, Danny E; Zhou, Huilin; Börner, G Valentin; Hollingsworth, Nancy M

    2015-12-01

    Interhomolog crossovers promote proper chromosome segregation during meiosis and are formed by the regulated repair of programmed double-strand breaks. This regulation requires components of the synaptonemal complex (SC), a proteinaceous structure formed between homologous chromosomes. In yeast, SC formation requires the "ZMM" genes, which encode a functionally diverse set of proteins, including the transverse filament protein, Zip1. In wild-type meiosis, Zmm proteins promote the biased resolution of recombination intermediates into crossovers that are distributed throughout the genome by interference. In contrast, noncrossovers are formed primarily through synthesis-dependent strand annealing mediated by the Sgs1 helicase. This work identifies a conserved region on the C terminus of Zip1 (called Zip1 4S), whose phosphorylation is required for the ZMM pathway of crossover formation. Zip1 4S phosphorylation is promoted both by double-strand breaks (DSBs) and the meiosis-specific kinase, MEK1/MRE4, demonstrating a role for MEK1 in the regulation of interhomolog crossover formation, as well as interhomolog bias. Failure to phosphorylate Zip1 4S results in meiotic prophase arrest, specifically in the absence of SGS1. This gain of function meiotic arrest phenotype is suppressed by spo11Δ, suggesting that it is due to unrepaired breaks triggering the meiotic recombination checkpoint. Epistasis experiments combining deletions of individual ZMM genes with sgs1-md zip1-4A indicate that Zip1 4S phosphorylation functions prior to the other ZMMs. These results suggest that phosphorylation of Zip1 at DSBs commits those breaks to repair via the ZMM pathway and provides a mechanism by which the crossover/noncrossover decision can be dynamically regulated during yeast meiosis.

  17. Phosphorylation of the Synaptonemal Complex Protein Zip1 Regulates the Crossover/Noncrossover Decision during Yeast Meiosis

    PubMed Central

    Chen, Xiangyu; Suhandynata, Ray T.; Sandhu, Rima; Rockmill, Beth; Mohibullah, Neeman; Niu, Hengyao; Liang, Jason; Lo, Hsiao-Chi; Miller, Danny E.; Zhou, Huilin; Börner, G. Valentin; Hollingsworth, Nancy M.

    2015-01-01

    Interhomolog crossovers promote proper chromosome segregation during meiosis and are formed by the regulated repair of programmed double-strand breaks. This regulation requires components of the synaptonemal complex (SC), a proteinaceous structure formed between homologous chromosomes. In yeast, SC formation requires the “ZMM” genes, which encode a functionally diverse set of proteins, including the transverse filament protein, Zip1. In wild-type meiosis, Zmm proteins promote the biased resolution of recombination intermediates into crossovers that are distributed throughout the genome by interference. In contrast, noncrossovers are formed primarily through synthesis-dependent strand annealing mediated by the Sgs1 helicase. This work identifies a conserved region on the C terminus of Zip1 (called Zip1 4S), whose phosphorylation is required for the ZMM pathway of crossover formation. Zip1 4S phosphorylation is promoted both by double-strand breaks (DSBs) and the meiosis-specific kinase, MEK1/MRE4, demonstrating a role for MEK1 in the regulation of interhomolog crossover formation, as well as interhomolog bias. Failure to phosphorylate Zip1 4S results in meiotic prophase arrest, specifically in the absence of SGS1. This gain of function meiotic arrest phenotype is suppressed by spo11Δ, suggesting that it is due to unrepaired breaks triggering the meiotic recombination checkpoint. Epistasis experiments combining deletions of individual ZMM genes with sgs1-md zip1-4A indicate that Zip1 4S phosphorylation functions prior to the other ZMMs. These results suggest that phosphorylation of Zip1 at DSBs commits those breaks to repair via the ZMM pathway and provides a mechanism by which the crossover/noncrossover decision can be dynamically regulated during yeast meiosis. PMID:26682552

  18. Transmission of Correlated Messages over Interference Channels with Strong Interference

    NASA Astrophysics Data System (ADS)

    Choi, Suhan; Yoon, Eunchul; Moon, Hichan

    Transmission of correlated messages over interference channels with strong interference is considered. As a result, an achievable rate region is presented. It is shown that if the messages are correlated, the achievable rate region can be larger than the capacity region given by Costa and El Gamal. As an example, the Gaussian interference channel is considered.

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

    USGS Publications Warehouse

    Millard, H.T.

    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.

  20. Kids Count [and] Families Count in Delaware: Fact Book, 1998.

    ERIC Educational Resources Information Center

    Nelson, Carl, Ed.; Wilson, Nancy, Ed.

    This Kids Count report is combined with Families Count, and provides information on statewide trends affecting children and families in Delaware. The first 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; (5) teen deaths; (6) juvenile…

  1. "Just" Counting: Young Children's Oral Counting and Enumeration

    ERIC Educational Resources Information Center

    Threlfall, John; Bruce, Bob

    2005-01-01

    This article focuses on the specific skills and abilities of young children in oral counting and enumeration. Responses to an oral counting task and an enumeration task by a sample (n=93) of 3- and 4-year old children attending a range of pre-five establishments in an urban district of northern England are described. The findings, whilst providing…

  2. Binaural modulation detection interference.

    PubMed

    Sheft, S; Yost, W A

    1997-09-01

    The ability to detect amplitude modulation (AM) of a tonal probe can be disrupted by the presence of modulated masking tones. Two experiments examined whether a disparity in the interaural parameters of the probe and masker can reduce the amount of interference. In the first experiment, the effects of interaural time and intensity differences were studied in separate sets of conditions. With low-frequency carriers, the detection of 10-Hz probe modulation in the presence of 10-Hz masker modulation was not significantly affected by interaural time differences. With higher-frequency carriers, dichotic stimuli were generated through combinations of diotic, dichotic, or monotic probe and masker presentations in which the probe and masker did not share a common interaural intensity difference. In these conditions, the amount of interference was affected by the interaural configuration. However, monotic level differences between the probe and masker may have contributed to the effect of interaural configuration. In the second experiment, the probe and masker were presented through separate speakers in an enclosed listening environment. Spatial separation between the sources for the probe and masker led to a small reduction in the amount of interference. When the masker modulation rate was varied with the probe AM rate fixed at 10 Hz, the extent of tuning in the modulation domain in the sound-field conditions was similar to that obtained with diotic stimulus presentation over headphones.

  3. Whole-Genome Analysis of Individual Meiotic Events in Drosophila melanogaster Reveals That Noncrossover Gene Conversions Are Insensitive to Interference and the Centromere Effect

    PubMed Central

    Miller, Danny E.; Smith, Clarissa B.; Kazemi, Nazanin Yeganeh; Cockrell, Alexandria J.; Arvanitakis, Alexandra V.; Blumenstiel, Justin P.; Jaspersen, Sue L.; Hawley, R. Scott

    2016-01-01

    A century of genetic analysis has revealed that multiple mechanisms control the distribution of meiotic crossover events. In Drosophila melanogaster, two significant positional controls are interference and the strongly polar centromere effect. Here, we assess the factors controlling the distribution of crossovers (COs) and noncrossover gene conversions (NCOs) along all five major chromosome arms in 196 single meiotic divisions to generate a more detailed understanding of these controls on a genome-wide scale. Analyzing the outcomes of single meiotic events allows us to distinguish among different classes of meiotic recombination. In so doing, we identified 291 NCOs spread uniformly among the five major chromosome arms and 541 COs (including 52 double crossovers and one triple crossover). We find that unlike COs, NCOs are insensitive to the centromere effect and do not demonstrate interference. Although the positions of COs appear to be determined predominately by the long-range influences of interference and the centromere effect, each chromosome may display a different pattern of sensitivity to interference, suggesting that interference may not be a uniform global property. In addition, unbiased sequencing of a large number of individuals allows us to describe the formation of de novo copy number variants, the majority of which appear to be mediated by unequal crossing over between transposable elements. This work has multiple implications for our understanding of how meiotic recombination is regulated to ensure proper chromosome segregation and maintain genome stability. PMID:26944917

  4. Whole-Genome Analysis of Individual Meiotic Events in Drosophila melanogaster Reveals That Noncrossover Gene Conversions Are Insensitive to Interference and the Centromere Effect.

    PubMed

    Miller, Danny E; Smith, Clarissa B; Kazemi, Nazanin Yeganeh; Cockrell, Alexandria J; Arvanitakas, Alexandra V; Blumenstiel, Justin P; Jaspersen, Sue L; Hawley, R Scott

    2016-05-01

    A century of genetic analysis has revealed that multiple mechanisms control the distribution of meiotic crossover events. In Drosophila melanogaster, two significant positional controls are interference and the strongly polar centromere effect. Here, we assess the factors controlling the distribution of crossovers (COs) and noncrossover gene conversions (NCOs) along all five major chromosome arms in 196 single meiotic divisions to generate a more detailed understanding of these controls on a genome-wide scale. Analyzing the outcomes of single meiotic events allows us to distinguish among different classes of meiotic recombination. In so doing, we identified 291 NCOs spread uniformly among the five major chromosome arms and 541 COs (including 52 double crossovers and one triple crossover). We find that unlike COs, NCOs are insensitive to the centromere effect and do not demonstrate interference. Although the positions of COs appear to be determined predominately by the long-range influences of interference and the centromere effect, each chromosome may display a different pattern of sensitivity to interference, suggesting that interference may not be a uniform global property. In addition, unbiased sequencing of a large number of individuals allows us to describe the formation of de novo copy number variants, the majority of which appear to be mediated by unequal crossing over between transposable elements. This work has multiple implications for our understanding of how meiotic recombination is regulated to ensure proper chromosome segregation and maintain genome stability.

  5. Particle and Photon Detection: Counting and Energy Measurement

    PubMed Central

    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

  6. Low-Background Counting at Homestake

    NASA Astrophysics Data System (ADS)

    Marshall, Iseley

    2009-10-01

    Background characterization at Homestake is an ongoing project crucial to the experiments located there. From neutrino physics to WIMP detection, low-background materials and their screening require highly sensitive detectors. Naturally, shielding is needed to lower ``noise'' in these detectors. Because of its vast depth, Homestake will be effective in shielding against cosmic-ray radiation. This means little, however, if radiation from materials used still interferes. Specifically, our group is working on designing the first low-background counting facility at the Homestake mine. Using a high-purity germanium crystal detector from ORTEC, measurements will be taken within a shield that is made to specifically account for radiation underground and fits the detector. Currently, in the design, there is a layer of copper surrounded by an intricate stainless steel casing, which will be manufactured air tight to accommodate for nitrogen purging. Lead will surround the stainless steel shell to further absorb gamma rays. A mobile lift system has been designed for easy access to the detector. In the future, this project will include multiple testing stations located in the famous Davis Cavern where future experiments will have the ability to use the site as an efficient and accurate counting facility for their needs (such as measuring radioactive isotopes in materials). Overall, this detector (and its shield system) is the beginning of a central testing facility that will serve Homestake's scientific community.

  7. Linguistic Interference in Immigrants' Interlanguage.

    ERIC Educational Resources Information Center

    Dole, Robert

    A study of the linguistic interference of nine multilingual immigrants to the Saguenay Peninsula of Quebec province examined three types of interference in their spoken English. They included: (1) interlingual interference from the mother tongue; (2) intralingual intrusion from structures and lexical items from within English in situations and…

  8. Interference Management in Heterogeneous Networks

    DTIC Science & Technology

    2013-06-01

    INTERFERENCE MANAGEMENT IN HETEROGENEOUS NETWORKS UNIVERSITY OF MARYLAND JUNE 2013 FINAL TECHNICAL REPORT APPROVED...3. DATES COVERED (From - To) AUG 2011 – FEB 2013 4. TITLE AND SUBTITLE INTERFERENCE MANAGEMENT IN HETEROGENEOUS NETWORKS 5a. CONTRACT NUMBER...However, such deployments require efficient frequency allocation schemes for managing interference from the pico- and macro base stations that are

  9. [Automated hematology analysers and spurious counts Part 3. Haemoglobin, red blood cells, cell count and indices, reticulocytes].

    PubMed

    Godon, Alban; Genevieve, Franck; Marteau-Tessier, Anne; Zandecki, Marc

    2012-01-01

    Several situations lead to abnormal haemoglobin measurement or to abnormal red blood cells (RBC) counts, including hyperlipemias, agglutinins and cryoglobulins, haemolysis, or elevated white blood cells (WBC) counts. Mean (red) cell volume may be also subject to spurious determination, because of agglutinins (mainly cold), high blood glucose level, natremia, anticoagulants in excess and at times technological considerations. Abnormality related to one measured parameter eventually leads to abnormal calculated RBC indices: mean cell haemoglobin content is certainly the most important RBC parameter to consider, maybe as important as flags generated by the haematology analysers (HA) themselves. In many circumstances, several of the measured parameters from cell blood counts (CBC) may be altered, and the discovery of a spurious change on one parameter frequently means that the validity of other parameters should be considered. Sensitive flags allow now the identification of several spurious counts, but only the most sophisticated HA have optimal flagging, and simpler ones, especially those without any WBC differential scattergram, do not share the same capacity to detect abnormal results. Reticulocytes are integrated into the CBC in many HA, and several situations may lead to abnormal counts, including abnormal gating, interference with intraerythrocytic particles, erythroblastosis or high WBC counts.

  10. Pressure and Temperature Sensors Using Two Spin Crossover Materials

    PubMed Central

    Jureschi, Catalin-Maricel; Linares, Jorge; Boulmaali, Ayoub; Dahoo, Pierre Richard; Rotaru, Aurelian; Garcia, Yann

    2016-01-01

    The possibility of a new design concept for dual spin crossover based sensors for concomitant detection of both temperature and pressure is presented. It is conjectured from numerical results obtained by mean field approximation applied to a Ising-like model that using two different spin crossover compounds containing switching molecules with weak elastic interactions it is possible to simultaneously measure P and T. When the interaction parameters are optimized, the spin transition is gradual and for each spin crossover compounds, both temperature and pressure values being identified from their optical densities. This concept offers great perspectives for smart sensing devices. PMID:26848663

  11. A crossover in the mechanical response of nanocrystalline ceramics.

    PubMed

    Szlufarska, Izabela; Nakano, Aiichiro; Vashishta, Priya

    2005-08-05

    Multimillion-atom molecular dynamics simulation of indentation of nanocrystalline silicon carbide reveals unusual deformation mechanisms in brittle nanophase materials, resulting from the coexistence of brittle grains and soft amorphous grain boundary phases. Simulations predict a crossover from intergranular continuous deformation to intragrain discrete deformation at a critical indentation depth. The crossover arises from the interplay between cooperative grain sliding, grain rotations, and intergranular dislocation formation similar to stick-slip behavior. The crossover is also manifested in switching from deformation dominated by indentation-induced crystallization to deformation dominated by disordering, leading to amorphization. This interplay between deformation mechanisms is critical for the design of ceramics with superior mechanical properties.

  12. Scale Invariance in 2D BCS-BEC Crossover

    NASA Astrophysics Data System (ADS)

    Sensarma, Rajdeep; Taylor, Edward; Randeria, Mohit

    2013-03-01

    In 2D BCS-BEC crossover, the frequency of the breathing mode in a harmonic trap, as well as the lower edge of the radio frequency spectroscopy response, show remarkable scale-invariance throughout the crossover regime, i.e. they are independent of the coupling constant. Using functional integral methods, we study the behaviour of these quantities in the 2D BCS-BEC crossover and comment on the possible reasons for this scale independence. RS was supported by DAE, Govt. of India. MR was supported by NSF Grant No. DMR-1006532. ET was supported by NSERC and the Canadian Institute for Advanced Research.

  13. Robust mainlobe interference suppression for coherent interference environment

    NASA Astrophysics Data System (ADS)

    Wang, Yasen; Bao, Qinglong; Chen, Zengping

    2016-12-01

    A mainlobe interference suppression method is proposed in this paper, which can still work when the signal of interest (SOI) is present in the training data. In this method, the iterative adaptive approach (IAA) is applied to spatial spectrum estimation at first. Then, IAA spatial spectrum is used to reconstruct the interference-plus-noise covariance matrix (INCM). Next, the eigenvector associated with mainlobe interference in INCM is determined, and the eigen-projection matrix can be calculated to suppress the mainlobe interference. Meanwhile, the sidelobe-interference-plus-noise covariance matrix (SINCM) can be reconstructed. Finally, the adaptive weight vector is obtained. One main advantage is that the proposed method can deal with coherent mainlobe interference and sidelobe interferences simultaneously. Simulation results demonstrate the effectiveness and robustness of the proposed method.

  14. Low White Blood Cell Count

    MedlinePlus

    Symptoms Low white blood cell count By Mayo Clinic Staff A low white blood cell count (leukopenia) is a decrease in disease-fighting cells ( ... a decrease in a certain type of white blood cell (neutrophil). The definition of low white blood cell ...

  15. Young Children Counting at Home

    ERIC Educational Resources Information Center

    Griffiths, Rose

    2007-01-01

    Learning to count is something that most children start to do by the time they are about two, and parents know from first-hand experience that family members play a big part in helping with this complex process. In this article, the author describes a project involving families sharing effective counting activities. The project called…

  16. Estimating efficacy in trials with selective crossover.

    PubMed

    Brentnall, Adam R; Sasieni, Peter; Cuzick, Jack

    2017-03-15

    When one arm in a trial has a worse early endpoint such as recurrence, a data-monitoring committee might recommend that all participants are offered the apparently superior treatment. The resultant crossover makes it difficult to measure differences between arms thereafter, including for longer-term endpoints such as mortality and disease-specific mortality. In this paper, we consider estimators of the efficacy of treatment on those who would not cross over if randomised to the apparently inferior arm. Binomial and proportional hazards maximum likelihood estimators are developed. The binomial estimator is applied to analysis of a breast cancer treatment trial and compared with intention-to-treat and inverse probability weighting estimators. Full and partial likelihood proportional-hazard model estimators are assessed through computer simulations, where they had similar bias and variance. The new efficacy estimators extend those for all-or-none compliance to this important problem. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  17. Laser frequency stabilization using bichromatic crossover spectroscopy

    SciTech Connect

    Jeong, Taek; Seb Moon, Han

    2015-03-07

    We propose a Doppler-free spectroscopic method named bichromatic crossover spectroscopy (BCS), which we then use for the frequency stabilization of an off-resonant frequency that does not correspond to an atomic transition. The observed BCS in the 5S{sub 1/2} → 5P{sub 1/2} transition of {sup 87}Rb is related to the hyperfine structure of the conventional saturated absorption spectrum of this transition. Furthermore, the Doppler-free BCS is numerically calculated by considering all of the degenerate magnetic sublevels of the 5S{sub 1/2} → 5P{sub 1/2} transition in an atomic vapor cell, and is found to be in good agreement with the experimental results. Finally, we successfully achieve modulation-free off-resonant locking at the center frequency between the two 5S{sub 1/2}(F = 1 and 2) → 5P{sub 1/2}(F′ = 1) transitions using a polarization rotation of the BCS. The laser frequency stability was estimated to be the Allan variance of 2.1 × 10{sup −10} at 1 s.

  18. Dimensional crossover in Richtmyer-Meshkov flows

    NASA Astrophysics Data System (ADS)

    Nishihara, Katsunobu; Bhowmick, Aklant K.; Abarzhi, Snezhana

    2016-11-01

    We analyze nonlinear dynamics of large scale coherent structures in Richtmyer-Meshkov flows. Group theory based analysis is applied with a detailed consideration of RM dynamics invariant with respect to p2mm (3D rectangular), p4mm (3D square) and pm1 (2D) groups. Symmetry dictates that asymptotic solutions form a 2 parameter family for rectangular flows and a 1 parameter family for 3D square and 2D flows. For 3D square and 2D symmetry, asymptotic solutions are obtained for the 1st and 2nd order of approximation and the fastest growth rate occurs at zero bubble curvatures. Fourier amplitudes exponentially decay with increase in order showing that solutions are convergent. Both 2D and 3D square solutions are stable with respect to symmetry conserving perturbations. Isotropic 3D square solutions are universally stable, while 2D solutions are unstable to anisotropic perturbations. Furthermore, the 3D and 2D solutions cannot be continuously transformed from one to another, and the dimensional crossover is discontinuous. The work is supported by the US National Science Foundation.

  19. Dimensional crossover in Richtmyer-Meshkov flows

    NASA Astrophysics Data System (ADS)

    Nishihara, Katsunobu; Bhowmick, Aklant; Abarzhi, Snezhana

    2016-10-01

    We analyze nonlinear dynamics of large scale coherent structures in Richtmyer-Meshkov flows. Group theoretic analysis is applied with a detailed consideration of p2mm (3D rectangular), p4mm (3D square) and pm1 (2D). Symmetry dictates that asymptotic solutions form a 2 parameter family for rectangular flows and a 1 parameter family for 3D square and 2D flows. For 3D square and 2D symmetry, asymptotic solutions are obtained for the 1st and 2nd order of approximation and the fastest growth rate occurs at zero bubble curvatures. Fourier amplitudes exponentially decay with increase in order showing that solutions are convergent. Both 2D and 3D square solutions are stable with respect to symmetry conserving perturbations. Isotropic 3D square solutions are universally stable, while 2D solutions are unstable to anisotropic perturbations. Furthermore, the 3D and 2D solutions cannot be continuously transformed from one form to another and the dimensional crossover is discontinuous. The work is supported by the US National Science Foundation.

  20. Standard Model thermodynamics across the electroweak crossover

    NASA Astrophysics Data System (ADS)

    Laine, M.; Meyer, M.

    2015-07-01

    Even though the Standard Model with a Higgs mass mH = 125GeV possesses no bulk phase transition, its thermodynamics still experiences a "soft point" at temperatures around T = 160GeV, with a deviation from ideal gas thermodynamics. Such a deviation may have an effect on precision computations of weakly interacting dark matter relic abundances if their mass is in the few TeV range, or on leptogenesis scenarios operating in this temperature range. By making use of results from lattice simulations based on a dimensionally reduced effective field theory, we estimate the relevant thermodynamic functions across the crossover. The results are tabulated in a numerical form permitting for their insertion as a background equation of state into cosmological particle production/decoupling codes. We find that Higgs dynamics induces a non-trivial "structure" visible e.g. in the heat capacity, but that in general the largest radiative corrections originate from QCD effects, reducing the energy density by a couple of percent from the free value even at T > 160GeV.

  1. Electrostatically-tuned dimensional crossover in nanowires

    NASA Astrophysics Data System (ADS)

    Tomczyk, Michelle; Cheng, Guanglei; Huang, Mengchen; Lee, Hyungwoo; Eom, Chang-Beom; Irvin, Patrick; Levy, Jeremy

    The electron system at the interface of two complex oxides, LaAlO3 and SrTiO3, exhibits a number of interesting strongly-correlated electronic properties, such as superconductivity and spin-orbit coupling. Reduced dimensionality is made accessible through nanowire devices created with conducting AFM lithography. Here, we describe an electrostatically-controlled dimensionality crossover in weak antilocalization behavior of LaAlO3/SrTiO3 nanowires at low temperature. These measurements give insight to the interplay of spin-orbit coupling and dimensionality. Characterizing the behavior of the strongly-correlated electronic properties in these reduced dimensions is necessary in order to develop this system as a multifunctional nanoelectronics platform. We gratefully acknowledge financial support from the following agencies and grants: ARO (W911NF-08-1-0317), AFOSR FA9550-10-1-0524 (JL) and FA9550-12-1-0342 (CBE), and NSF (DMR-1104191, DMR-1124131 (JL), ONR N00014-15-1-2847 (JL) and DMR-1234096 (CBE).

  2. Standard Model thermodynamics across the electroweak crossover

    SciTech Connect

    Laine, M.; Meyer, M. E-mail: meyer@itp.unibe.ch

    2015-07-01

    Even though the Standard Model with a Higgs mass m{sub H} = 125GeV possesses no bulk phase transition, its thermodynamics still experiences a 'soft point' at temperatures around T = 160GeV, with a deviation from ideal gas thermodynamics. Such a deviation may have an effect on precision computations of weakly interacting dark matter relic abundances if their mass is in the few TeV range, or on leptogenesis scenarios operating in this temperature range. By making use of results from lattice simulations based on a dimensionally reduced effective field theory, we estimate the relevant thermodynamic functions across the crossover. The results are tabulated in a numerical form permitting for their insertion as a background equation of state into cosmological particle production/decoupling codes. We find that Higgs dynamics induces a non-trivial 'structure' visible e.g. in the heat capacity, but that in general the largest radiative corrections originate from QCD effects, reducing the energy density by a couple of percent from the free value even at T > 160GeV.

  3. Standard Model thermodynamics across the electroweak crossover

    SciTech Connect

    Laine, M.; Meyer, M.

    2015-07-22

    Even though the Standard Model with a Higgs mass m{sub \\tiny H}=125 GeV possesses no bulk phase transition, its thermodynamics still experiences a “soft point” at temperatures around T=160 GeV, with a deviation from ideal gas thermodynamics. Such a deviation may have an effect on precision computations of weakly interacting dark matter relic abundances if their mass is in the few TeV range, or on leptogenesis scenarios operating in this temperature range. By making use of results from lattice simulations based on a dimensionally reduced effective field theory, we estimate the relevant thermodynamic functions across the crossover. The results are tabulated in a numerical form permitting for their insertion as a background equation of state into cosmological particle production/decoupling codes. We find that Higgs dynamics induces a non-trivial “structure” visible e.g. in the heat capacity, but that in general the largest radiative corrections originate from QCD effects, reducing the energy density by a couple of percent from the free value even at T>160 GeV.

  4. Microelectromechanical systems integrating molecular spin crossover actuators

    NASA Astrophysics Data System (ADS)

    Manrique-Juarez, Maria D.; Rat, Sylvain; Mathieu, Fabrice; Saya, Daisuke; Séguy, Isabelle; Leïchlé, Thierry; Nicu, Liviu; Salmon, Lionel; Molnár, Gábor; Bousseksou, Azzedine

    2016-08-01

    Silicon MEMS cantilevers coated with a 200 nm thin layer of the molecular spin crossover complex [Fe(H2B(pz)2)2(phen)] (H2B(pz)2 = dihydrobis(pyrazolyl)borate and phen = 1,10-phenantroline) were actuated using an external magnetic field and their resonance frequency was tracked by means of integrated piezoresistive detection. The light-induced spin-state switching of the molecules from the ground low spin to the metastable high spin state at 10 K led to a well-reproducible shift of the cantilever's resonance frequency (Δfr = -0.52 Hz). Control experiments at different temperatures using coated as well as uncoated devices along with simple calculations support the assignment of this effect to the spin transition. This latter translates into changes in mechanical behavior of the cantilever due to the strong spin-state/lattice coupling. A guideline for the optimization of device parameters is proposed so as to efficiently harness molecular scale movements for large-scale mechanical work, thus paving the road for nanoelectromechanical systems (NEMS) actuators based on molecular materials.

  5. Interference Rejection and Management

    DTIC Science & Technology

    2009-07-01

    filtering matrix for the noise and interference that is defined as Cnoise = [ 0N ,G−M Toeplitz ([ c∗M−1, 01,N−1 ]T [c∗, 01,N−1 ])] , (9.30) where 0i, j...is the i × j zero matrix. The Toeplitz operator, Toeplitz (column, row), generates a Toeplitz matrix from a column vector and a row vector. Note that...2002). 22. Gray, R.M.: Toeplitz and circulant matrices: A review. Foundations Trends Commun. Inform. Theory 2, 155–239 (2006). 23. Hara, S., Prasad, R

  6. Sensors Locate Radio Interference

    NASA Technical Reports Server (NTRS)

    2009-01-01

    After receiving a NASA Small Business Innovation Research (SBIR) contract from Kennedy Space Center, Soneticom Inc., based in West Melbourne, Florida, created algorithms for time difference of arrival and radio interferometry, which it used in its Lynx Location System (LLS) to locate electromagnetic interference that can disrupt radio communications. Soneticom is collaborating with the Federal Aviation Administration (FAA) to install and test the LLS at its field test center in New Jersey in preparation for deploying the LLS at commercial airports. The software collects data from each sensor in order to compute the location of the interfering emitter.

  7. Self-affinity and Crossover of A Clay Deposit

    NASA Astrophysics Data System (ADS)

    Fossum, J. O.; Huru Bergene, H.; Hansen, A.; Manificat, G.

    Self-affine dehydrated colloidal deposits on fresh mica surfaces of the synthetic 2:1 smectite clay laponite have been studied by means of Atomic Force Microscopy. AFM images of these prepared assemblies of sol and gel aggregates have been analyzed both by means of standard AFM software, and wavelet methods. The deposited surfaces show an anti-persistent to persistent crossover with a clay concentration dependent crossover length. It is thus concluded that the investigated electrolyte concentrations play a minor role

  8. White blood cell counting system

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The design, fabrication, and tests of a prototype white blood cell counting system for use in the Skylab IMSS are presented. The counting system consists of a sample collection subsystem, sample dilution and fluid containment subsystem, and a cell counter. Preliminary test results show the sample collection and the dilution subsystems are functional and fulfill design goals. Results for the fluid containment subsystem show the handling bags cause counting errors due to: (1) adsorption of cells to the walls of the container, and (2) inadequate cleaning of the plastic bag material before fabrication. It was recommended that another bag material be selected.

  9. Beamforming design with proactive interference cancelation in MISO interference channels

    NASA Astrophysics Data System (ADS)

    Li, Yang; Tian, Yafei; Yang, Chenyang

    2015-12-01

    In this paper, we design coordinated beamforming at base stations (BSs) to facilitate interference cancelation at users in interference networks, where each BS is equipped with multiple antennas and each user is with a single antenna. By assuming that each user can select the best decoding strategy to mitigate the interference, either canceling the interference after decoding when it is strong or treating it as noise when it is weak, we optimize the beamforming vectors that maximize the sum rate for the networks under different interference scenarios and find the solutions of beamforming with closed-form expressions. The inherent design principles are then analyzed, and the performance gain over passive interference cancelation is demonstrated through simulations in heterogeneous cellular networks.

  10. Separable Crossover-Promoting and Crossover-Constraining Aspects of Zip1 Activity during Budding Yeast Meiosis

    PubMed Central

    Voelkel-Meiman, Karen; Johnston, Cassandra; Thappeta, Yashna; Subramanian, Vijayalakshmi V.; Hochwagen, Andreas; MacQueen, Amy J.

    2015-01-01

    Accurate chromosome segregation during meiosis relies on the presence of crossover events distributed among all chromosomes. MutSγ and MutLγ homologs (Msh4/5 and Mlh1/3) facilitate the formation of a prominent group of meiotic crossovers that mature within the context of an elaborate chromosomal structure called the synaptonemal complex (SC). SC proteins are required for intermediate steps in the formation of MutSγ-MutLγ crossovers, but whether the assembled SC structure per se is required for MutSγ-MutLγ-dependent crossover recombination events is unknown. Here we describe an interspecies complementation experiment that reveals that the mature SC is dispensable for the formation of Mlh3-dependent crossovers in budding yeast. Zip1 forms a major structural component of the budding yeast SC, and is also required for MutSγ and MutLγ-dependent crossover formation. Kluyveromyces lactis ZIP1 expressed in place of Saccharomyces cerevisiae ZIP1 in S. cerevisiae cells fails to support SC assembly (synapsis) but promotes wild-type crossover levels in those nuclei that progress to form spores. While stable, full-length SC does not assemble in S. cerevisiae cells expressing K. lactis ZIP1, aggregates of K. lactis Zip1 displayed by S. cerevisiae meiotic nuclei are decorated with SC-associated proteins, and K. lactis Zip1 promotes the SUMOylation of the SC central element protein Ecm11, suggesting that K. lactis Zip1 functionally interfaces with components of the S. cerevisiae synapsis machinery. Moreover, K. lactis Zip1-mediated crossovers rely on S. cerevisiae synapsis initiation proteins Zip3, Zip4, Spo16, as well as the Mlh3 protein, as do the crossovers mediated by S. cerevisiae Zip1. Surprisingly, however, K. lactis Zip1-mediated crossovers are largely Msh4/Msh5 (MutSγ)-independent. This separation-of-function version of Zip1 thus reveals that neither assembled SC nor MutSγ is required for Mlh3-dependent crossover formation per se in budding yeast. Our data

  11. The dynamical crossover in attractive colloidal systems

    SciTech Connect

    Mallamace, Francesco; Corsaro, Carmelo; Stanley, H. Eugene; Mallamace, Domenico; Chen, Sow-Hsin

    2013-12-07

    We study the dynamical arrest in an adhesive hard-sphere colloidal system. We examine a micellar suspension of the Pluronic-L64 surfactant in the temperature (T) and volume fraction (ϕ) phase diagram. According to mode-coupling theory (MCT), this system is characterized by a cusp-like singularity and two glassy phases: an attractive glass (AG) phase and a repulsive glass (RG) phase. The T − ϕ phase diagram of this system as confirmed by a previous series of scattering data also exhibits a Percolation Threshold (PT) line, a reentrant behavior (AG-liquid-RG), and a glass-to-glass transition. The AG phase can be generated out of the liquid phase by using T and ϕ as control parameters. We utilize viscosity and nuclear magnetic resonance (NMR) techniques. NMR data confirm all the characteristic properties of the colloidal system phase diagram and give evidence of the onset of a fractal-like percolating structure at a precise threshold. The MCT scaling laws used to study the shear viscosity as a function of ϕ and T show in both cases a fragile-to-strong liquid glass-forming dynamic crossover (FSC) located near the percolation threshold where the clustering process is fully developed. These results suggest a larger thermodynamic generality for this phenomenon, which is usually studied only as a function of the temperature. We also find that the critical values of the control parameters, coincident with the PT line, define the locus of the FSC. In the region between the FSC and the glass transition lines the system dynamics are dominated by clustering effects. We thus demonstrate that it is possible, using the conceptual framework provided by extended mode-coupling theory, to describe the way a system approaches dynamic arrest, taking into account both cage and hopping effects.

  12. Counting Triangles to Sum Squares

    ERIC Educational Resources Information Center

    DeMaio, Joe

    2012-01-01

    Counting complete subgraphs of three vertices in complete graphs, yields combinatorial arguments for identities for sums of squares of integers, odd integers, even integers and sums of the triangular numbers.

  13. Demonstrations of beats as moving interference patterns

    NASA Astrophysics Data System (ADS)

    Stein, T. S.; Dishman, L. G.

    1982-02-01

    A ripple tank demonstration is described that displays the dynamic interference patterns responsible for producing beats. Photographs are provided of a computer simulation of various beat interference patterns. Young's two-slit interference pattern is presented as a special case (the zero-beat case) of the more general beat interference pattern. Equations for the constructive interference paths of beat interference patterns are derived.

  14. Single-plasmon interferences.

    PubMed

    Dheur, Marie-Christine; Devaux, Eloïse; Ebbesen, Thomas W; Baron, Alexandre; Rodier, Jean-Claude; Hugonin, Jean-Paul; Lalanne, Philippe; Greffet, Jean-Jacques; Messin, Gaétan; Marquier, François

    2016-03-01

    Surface plasmon polaritons are electromagnetic waves coupled to collective electron oscillations propagating along metal-dielectric interfaces, exhibiting a bosonic character. Recent experiments involving surface plasmons guided by wires or stripes allowed the reproduction of quantum optics effects, such as antibunching with a single surface plasmon state, coalescence with a two-plasmon state, conservation of squeezing, or entanglement through plasmonic channels. We report the first direct demonstration of the wave-particle duality for a single surface plasmon freely propagating along a planar metal-air interface. We develop a platform that enables two complementary experiments, one revealing the particle behavior of the single-plasmon state through antibunching, and the other one where the interferences prove its wave nature. This result opens up new ways to exploit quantum conversion effects between different bosonic species as shown here with photons and polaritons.

  15. Single-plasmon interferences

    PubMed Central

    Dheur, Marie-Christine; Devaux, Eloïse; Ebbesen, Thomas W.; Baron, Alexandre; Rodier, Jean-Claude; Hugonin, Jean-Paul; Lalanne, Philippe; Greffet, Jean-Jacques; Messin, Gaétan; Marquier, François

    2016-01-01

    Surface plasmon polaritons are electromagnetic waves coupled to collective electron oscillations propagating along metal-dielectric interfaces, exhibiting a bosonic character. Recent experiments involving surface plasmons guided by wires or stripes allowed the reproduction of quantum optics effects, such as antibunching with a single surface plasmon state, coalescence with a two-plasmon state, conservation of squeezing, or entanglement through plasmonic channels. We report the first direct demonstration of the wave-particle duality for a single surface plasmon freely propagating along a planar metal-air interface. We develop a platform that enables two complementary experiments, one revealing the particle behavior of the single-plasmon state through antibunching, and the other one where the interferences prove its wave nature. This result opens up new ways to exploit quantum conversion effects between different bosonic species as shown here with photons and polaritons. PMID:26998521

  16. Counting on Using a Number Game

    ERIC Educational Resources Information Center

    Betts, Paul

    2015-01-01

    Counting all and counting on are distinct counting strategies that can be used to compute such quantities as the total number of objects in two sets (Wright, Martland, and Stafford 2010). Given five objects and three more objects, for example, children who use counting all to determine quantity will count both collections; that is, they count…

  17. Optically bistable interference filter

    NASA Astrophysics Data System (ADS)

    Feng, Weiting

    1990-07-01

    In general the temperature dependence of refractive index of coating materials is usually small. The most notable exception being the lead telluride. Thinfilm filters made of PbTe possess anomalously high nortlinearily in refractive index. We have investigated the phenomenon theoretically and experimexitally. 2 . BISTABLE CHARACTERISTICS OF INTERFERENCE FILTERS It can be proved that the transmittance and reflectance of a twin-cavity NLIF which consists of two F-B filters coupled by a single low-index are given by 2 a(1r1 )(1-r0) T --i. -. (1) -d (1r01) (1r12) (1-i-Fsin 4)(1+sin p) where a r01 F . Te phase change of the cavity 0 IS 2r0dnAI0D (2) 2k5dT 1k where the absorbtance A 00 the initial detunning of fresonance and the first term on the right side of the equation(1)-(2) the output characteristics of the NLIF can be calculated. 3 . EXPERIMENTAL CASE The interference filters suggested to be used in my research will be made by vacuum deposition with a thermal source. The filters will be made according to the prescripti The dominant mechanism responsible for d(nhl) must be the change in the refractive index. A low limit on the OB switch-on time is found to be O. 35us and switch-off time is 5. 5us. 4. REFERENCES 1. W. T. Feng " Temperature effects on properties of zinc selenide and lead telluride" to be published in Infrared Physics. 2. H. S. Carslaw Conduction

  18. The limits of counting accuracy in distributed neural representations.

    PubMed

    Gardner-Medwin, A R; Barlow, H B

    2001-03-01

    Learning about a causal or statistical association depends on comparing frequencies of joint occurrence with frequencies expected from separate occurrences, and to do this, events must somehow be counted. Physiological mechanisms can easily generate the necessary measures if there is a direct, one-to-one relationship between significant events and neural activity, but if the events are represented across cell populations in a distributed manner, the counting of one event will be interfered with by the occurrence of others. Although the mean interference can be allowed for, there is inevitably an increase in the variance of frequency estimates that results in the need for extra data to achieve reliable learning. This lowering of statistical efficiency (Fisher, 1925) is calculated as the ratio of the minimum to actual variance of the estimates. We define two neural models, based on presynaptic and Hebbian synaptic modification, and explore the effects of sparse coding and the relative frequencies of events on the efficiency of frequency estimates. High counting efficiency must be a desirable feature of biological representations, but the results show that the number of events that can be counted simultaneously with 50% efficiency is fewer than the number of cells or 0.1-0.25 of the number of synapses (on the two models) - many fewer than can be unambiguously represented. Direct representations would lead to greater counting efficiency, but distributed representations have the versatility of detecting and counting many unforeseen or rare events. Efficient counting of rare but important events requires that they engage more active cells than common or unimportant ones. The results suggest reasons that representations in the cerebral cortex appear to use extravagant numbers of cells and modular organization, and they emphasize the importance of neuronal trigger features and the phenomena of habituation and attention.

  19. Experimental interference of independent photons.

    PubMed

    Kaltenbaek, Rainer; Blauensteiner, Bibiane; Zukowski, Marek; Aspelmeyer, Markus; Zeilinger, Anton

    2006-06-23

    Interference of photons emerging from independent sources is essential for modern quantum-information processing schemes, above all quantum repeaters and linear-optics quantum computers. We report an observation of nonclassical interference of two single photons originating from two independent, separated sources, which were actively synchronized with a rms timing jitter of 260 fs. The resulting (two-photon) interference visibility was (83+/-4)%.

  20. [Case-crossover design: Basic essentials and applications].

    PubMed

    Carracedo-Martínez, Eduardo; Tobías, Aurelio; Saez, Marc; Taracido, Margarita; Figueiras, Adolfo

    2009-01-01

    Case-crossover analysis is an observational epidemiological design that was proposed by Maclure in 1991 to assess whether a given intermittent or unusual exposure may have triggered an immediate short-term, acute event. The present article outlines the basics of case-crossover designs, as well as their applications and limitations. The case-crossover design is based on exclusively selecting case subjects. To calculate relative risk, exposure during the period of time prior to the event (case period) is compared against the same subject's exposure during one or more control periods. This method is only appropriate when the exposures are transient in time and have acute short-term effects. For exposures in which there is no trend, a unidirectional approach is the most frequent and consists of selecting one or more control periods prior to the case period. When the exposure displays a time trend (e.g., air pollution), a unidirectional approach will yield biased estimates, and therefore bidirectional case-crossover designs are used, which select control time intervals preceding and subsequent to that of the event. The case-crossover design is being increasingly used across a wide range of fields, including factors triggering traffic, occupational and domestic accidents and acute myocardial infarction, and those involved in air pollution and health and pharmacoepidemiology, among others. Insofar as data-analysis is concerned, case-crossover designs can generally be regarded as matched case-control studies and consequently conditional logistic regression can be applied. Lastly, this study analyzes practical examples of distinct applications of the case-crossover design.

  1. Detection of crossover time scales in multifractal detrended fluctuation analysis

    NASA Astrophysics Data System (ADS)

    Ge, Erjia; Leung, Yee

    2013-04-01

    Fractal is employed in this paper as a scale-based method for the identification of the scaling behavior of time series. Many spatial and temporal processes exhibiting complex multi(mono)-scaling behaviors are fractals. One of the important concepts in fractals is crossover time scale(s) that separates distinct regimes having different fractal scaling behaviors. A common method is multifractal detrended fluctuation analysis (MF-DFA). The detection of crossover time scale(s) is, however, relatively subjective since it has been made without rigorous statistical procedures and has generally been determined by eye balling or subjective observation. Crossover time scales such determined may be spurious and problematic. It may not reflect the genuine underlying scaling behavior of a time series. The purpose of this paper is to propose a statistical procedure to model complex fractal scaling behaviors and reliably identify the crossover time scales under MF-DFA. The scaling-identification regression model, grounded on a solid statistical foundation, is first proposed to describe multi-scaling behaviors of fractals. Through the regression analysis and statistical inference, we can (1) identify the crossover time scales that cannot be detected by eye-balling observation, (2) determine the number and locations of the genuine crossover time scales, (3) give confidence intervals for the crossover time scales, and (4) establish the statistically significant regression model depicting the underlying scaling behavior of a time series. To substantive our argument, the regression model is applied to analyze the multi-scaling behaviors of avian-influenza outbreaks, water consumption, daily mean temperature, and rainfall of Hong Kong. Through the proposed model, we can have a deeper understanding of fractals in general and a statistical approach to identify multi-scaling behavior under MF-DFA in particular.

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

    PubMed

    Balpardo, C; Capoulat, M E; Rodrigues, D; Arenillas, P

    2010-01-01

    The nuclide (241)Am decays by alpha emission to (237)Np. Most of the decays (84.6%) populate the excited level of (237)Np with energy of 59.54 keV. Digital coincidence counting was applied to standardize a solution of (241)Am 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.

  3. Macrocycle-based spin-crossover materials.

    PubMed

    El Hajj, Fatima; Sebki, Ghania; Patinec, Véronique; Marchivie, Mathieu; Triki, Smail; Handel, Henri; Yefsah, Said; Tripier, Raphaël; Gómez-García, Carlos J; Coronado, Eugenio

    2009-11-02

    New iron(II) complexes of formula [Fe(L1)](BF(4))(2) (1) and [Fe(L2)](BF(4))(2) x H(2)O (2) (L1 = 1,7-bis(2'-pyridylmethyl)-1,4,7,10-tetraazacyclododecane; L2 = 1,8-bis(2'-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane) have been synthesized and characterized by infrared spectroscopy, variable-temperature single-crystal X-ray diffraction, and variable-temperature magnetic susceptibility measurements. The crystal structure determinations of 1 and 2 reveal in both cases discrete iron(II) monomeric structures in which the two functionalized tetraazamacrocycles (L1 and L2) act as hexadentate ligands; the iron(II) ions are coordinated with six nitrogen atoms: four from the macrocycle and two from two pyridine groups occupying two cis positions around the metal ion. In 1, the N-Fe-N bond angles indicate that the Fe(II) ion adopts an unusual distorted trigonal prismatic geometry. In agreement with the observed paramagnetic behavior, the average of the six Fe-N distances at 293 K (2.218(6) A) and at 90 K (2.209(2) A) correspond well with distances observed for high-spin (HS) Fe(II) complexes with a coordination index of 6. For 2, the Fe(II) ion adopts a distorted octahedral geometry for which the six Fe-N distances (average 2.197(4) A) at room temperature are in the range expected for HS Fe(II) complexes. The crystal structure solved at 90 K showed a strong modification of the iron coordination sphere, suggesting the presence of a spin-crossover transition from HS to low spin (LS). Surprisingly, the averaged Fe-N value (2.077(4) A) at this temperature is not in agreement with the magnetic measurements since the chi(m)T product versus T showed a full LS state at 90 K. This may be explained by the presence of important distortions arising from the macrocycle constraints. To understand how the crystal and the lattice parameters were affected by the magnetic transition, the temperature dependence of the lattice parameters of 2 was determined in the range 293-90 K: the a and

  4. Interference pattern period measurement at picometer level

    NASA Astrophysics Data System (ADS)

    Xiang, Xiansong; Wei, Chunlong; Jia, Wei; Zhou, Changhe; Li, Minkang; Lu, Yancong

    2016-10-01

    To produce large scale gratings by Scanning Beam Interference Lithography (SBIL), a light spot containing grating pattern is generated by two beams interfering, and a scanning stage is used to drive the substrate moving under the light spot. In order to locate the stage at the proper exposure positions, the period of the Interference pattern must be measured accurately. We developed a set of process to obtain the period value of two interfering beams at picometer level. The process includes data acquisition and data analysis. The data is received from a photodiode and a laser interferometer with sub-nanometer resolution. Data analysis differs from conventional analyzing methods like counting wave peaks or using Fourier transform to get the signal period, after a preprocess of filtering and envelope removing, the mean square error is calculated between the received signal and ideal sinusoid waves to find the best-fit frequency, thus an accuracy period value is acquired, this method has a low sensitivity to amplitude noise and a high resolution of frequency. With 405nm laser beams interfering, a pattern period value around 562nm is acquired by employing this process, fitting diagram of the result shows the accuracy of the period value reaches picometer level, which is much higher than the results of conventional methods.

  5. Solving the Traveling Salesman Problem through Extended Changing Crossover Operators

    NASA Astrophysics Data System (ADS)

    Takahashi, Ryouei

    In order to efficiently obtain an approximate solution of the traveling salesman problem (TSP), extended changing crossover operators (ECXOs) which can substitute any crossover operator of genetic algorithms (GAs) and ant colony optimization (ACO) for another crossover operator at any time is proposed. In this investigation our ECXO uses both EX (or ACO) and EXX (Edge Exchange Crossover) in early generations to create local optimum sub-paths, and it uses EAX (Edge Assembly Crossover) to create a global optimum solution after generations. With EX or ACO any individual or any ant determines the next city he visits from lengths of edges or tours' lengths deposited on edges as pheromone, and he generates local optimum paths. With EXX the generated path converges to a provisional optimal path. With EAX a parent exchanges his edges with another parent's ones reciprocally to create sub-cyclic paths, before restructuring a cyclic path by combining the sub-cyclic paths with making distances between them minimum. In this paper validity of ECXO is verified by our C experiments using medium-sized problems in TSPLIB, and it is shown that ECXO can find the best solution earlier than EAX.

  6. Orbital Transfer Vehicle Engine Technology High Velocity Ratio Diffusing Crossover

    NASA Technical Reports Server (NTRS)

    Lariviere, Brian W.

    1992-01-01

    High speed, high efficiency head rise multistage pumps require continuous passage diffusing crossovers to effectively convey the pumped fluid from the exit of one impeller to the inlet of the next impeller. On Rocketdyne's Orbital Transfer Vehicle (OTV), the MK49-F, a three stage high pressure liquid hydrogen turbopump, utilizes a 6.23 velocity ratio diffusing crossover. This velocity ratio approaches the diffusion limits for stable and efficient flow over the operating conditions required by the OTV system. The design of the high velocity ratio diffusing crossover was based on advanced analytical techniques anchored by previous tests of stationary two-dimensional diffusers with steady flow. To secure the design and the analytical techniques, tests were required with the unsteady whirling characteristics produced by an impeller. A tester was designed and fabricated using a 2.85 times scale model of the MK49-F turbopumps first stage, including the inducer, impeller, and the diffusing crossover. Water and air tests were completed to evaluate the large scale turbulence, non-uniform velocity, and non-steady velocity on the pump and crossover head and efficiency. Suction performance tests from 80 percent to 124 percent of design flow were completed in water to assess these pump characteristics. Pump and diffuser performance from the water and air tests were compared with the actual MK49-F test data in liquid hydrogen.

  7. Orbital transfer vehicle engine technology high velocity ratio diffusing crossover

    NASA Astrophysics Data System (ADS)

    Lariviere, Brian W.

    1992-12-01

    High speed, high efficiency head rise multistage pumps require continuous passage diffusing crossovers to effectively convey the pumped fluid from the exit of one impeller to the inlet of the next impeller. On Rocketdyne's Orbital Transfer Vehicle (OTV), the MK49-F, a three stage high pressure liquid hydrogen turbopump, utilizes a 6.23 velocity ratio diffusing crossover. This velocity ratio approaches the diffusion limits for stable and efficient flow over the operating conditions required by the OTV system. The design of the high velocity ratio diffusing crossover was based on advanced analytical techniques anchored by previous tests of stationary two-dimensional diffusers with steady flow. To secure the design and the analytical techniques, tests were required with the unsteady whirling characteristics produced by an impeller. A tester was designed and fabricated using a 2.85 times scale model of the MK49-F turbopumps first stage, including the inducer, impeller, and the diffusing crossover. Water and air tests were completed to evaluate the large scale turbulence, non-uniform velocity, and non-steady velocity on the pump and crossover head and efficiency. Suction performance tests from 80 percent to 124 percent of design flow were completed in water to assess these pump characteristics. Pump and diffuser performance from the water and air tests were compared with the actual MK49-F test data in liquid hydrogen.

  8. A Link between Meiotic Prophase Progression and CrossoverControl

    SciTech Connect

    Carlton, Peter M.; Farruggio, Alfonso P.; Dernburg, Abby F.

    2005-07-06

    During meiosis, most organisms ensure that homologous chromosomes undergo at least one exchange of DNA, or crossover, to link chromosomes together and accomplish proper segregation. How each chromosome receives a minimum of one crossover is unknown. During early meiosis in Caenorhabditis elegans and many other species, chromosomes adopt a polarized organization within the nucleus, which normally disappears upon completion of homolog synapsis. Mutations that impair synapsis even between a single pair of chromosomes in C. elegans delay this nuclear reorganization. We quantified this delay by developing a classification scheme for discrete stages of meiosis. Immunofluorescence localization of RAD-51 protein revealed that delayed meiotic cells also contained persistent recombination intermediates. Through genetic analysis, we found that this cytological delay in meiotic progression requires double-strand breaks and the function of the crossover-promoting heteroduplex HIM-14 (Msh4) and MSH-5. Failure of X chromosome synapsis also resulted in impaired crossover control on autosomes, which may result from greater numbers and persistence of recombination intermediates in the delayed nuclei. We conclude that maturation of recombination events on chromosomes promotes meiotic progression, and is coupled to the regulation of crossover number and placement. Our results have broad implications for the interpretation of meiotic mutants, as we have shown that asynapsis of a single chromosome pair can exert global effects on meiotic progression and recombination frequency.

  9. Hanford whole body counting manual

    SciTech Connect

    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.

  10. Supersonic Wave Interference Affecting Stability

    NASA Technical Reports Server (NTRS)

    Love, Eugene S.

    1958-01-01

    Some of the significant interference fields that may affect stability of aircraft at supersonic speeds are briefly summarized. Illustrations and calculations are presented to indicate the importance of interference fields created by wings, bodies, wing-body combinations, jets, and nacelles.

  11. Sleep can reduce proactive interference.

    PubMed

    Abel, Magdalena; Bäuml, Karl-Heinz T

    2014-01-01

    Sleep has repeatedly been connected to processes of memory consolidation. While extensive research indeed documents beneficial effects of sleep on memory, little is yet known about the role of sleep for interference effects in episodic memory. Although two prior studies reported sleep to reduce retroactive interference, no sleep effect has previously been found for proactive interference. Here we applied a study format differing from that employed by the prior studies to induce a high degree of proactive interference, and asked participants to encode a single list or two interfering lists of paired associates via pure study cycles. Testing occurred after 12 hours of diurnal wakefulness or nocturnal sleep. Consistent with the prior work, we found sleep in comparison to wake did not affect memory for the single list, but reduced retroactive interference. In addition we found sleep reduced proactive interference, and reduced retroactive and proactive interference to the same extent. The finding is consistent with the view that arising benefits of sleep are caused by the reactivation of memory contents during sleep, which has been suggested to strengthen and stabilise memories. Such stabilisation may make memories less susceptible to competition from interfering memories at test and thus reduce interference effects.

  12. Output Interference in Recognition Memory

    ERIC Educational Resources Information Center

    Criss, Amy H.; Malmberg, Kenneth J.; Shiffrin, Richard M.

    2011-01-01

    Dennis and Humphreys (2001) proposed that interference in recognition memory arises solely from the prior contexts of the test word: Interference does not arise from memory traces of other words (from events prior to the study list or on the study list, and regardless of similarity to the test item). We evaluate this model using output…

  13. Interference Phenomenon with Mobile Displays

    ERIC Educational Resources Information Center

    Trantham, Kenneth

    2015-01-01

    A simple experiment is presented in which the spacing and geometric pattern of pixels in mobile displays is measured. The technique is based on optical constructive interference. While the experiment is another opportunity to demonstrate wave interference from a grating-like structure, this can also be used to demonstrate concepts of solid state…

  14. Corynebacterium glutamicum Metabolic Engineering with CRISPR Interference (CRISPRi).

    PubMed

    Cleto, Sara; Jensen, Jaide Vk; Wendisch, Volker F; Lu, Timothy K

    2016-05-20

    Corynebacterium glutamicum is an important organism for the industrial production of amino acids. Metabolic pathways in this organism are usually engineered by conventional methods such as homologous recombination, which depends on rare double-crossover events. To facilitate the mapping of gene expression levels to metabolic outputs, we applied CRISPR interference (CRISPRi) technology using deactivated Cas9 (dCas9) to repress genes in C. glutamicum. We then determined the effects of target repression on amino acid titers. Single-guide RNAs directing dCas9 to specific targets reduced expression of pgi and pck up to 98%, and of pyk up to 97%, resulting in titer enhancement ratios of l-lysine and l-glutamate production comparable to levels achieved by gene deletion. This approach for C. glutamicum metabolic engineering, which only requires 3 days, indicates that CRISPRi can be used for quick and efficient metabolic pathway remodeling without the need for gene deletions or mutations and subsequent selection.

  15. LINEAR COUNT-RATE METER

    DOEpatents

    Henry, J.J.

    1961-09-01

    A linear count-rate meter is designed to provide a highly linear output while receiving counting rates from one cycle per second to 100,000 cycles per second. Input pulses enter a linear discriminator and then are fed to a trigger circuit which produces positive pulses of uniform width and amplitude. The trigger circuit is connected to a one-shot multivibrator. The multivibrator output pulses have a selected width. Feedback means are provided for preventing transistor saturation in the multivibrator which improves the rise and decay times of the output pulses. The multivibrator is connected to a diode-switched, constant current metering circuit. A selected constant current is switched to an averaging circuit for each pulse received, and for a time determined by the received pulse width. The average output meter current is proportional to the product of the counting rate, the constant current, and the multivibrator output pulse width.

  16. Photon Counting - One More Time

    NASA Astrophysics Data System (ADS)

    Stanton, Richard H.

    2012-05-01

    Photon counting has been around for more than 60 years, and has been available to amateurs for most of that time. In most cases single photons are detected using photomultiplier tubes, "old technology" that became available after the Second World War. But over the last couple of decades the perfection of CCD devices has given amateurs the ability to perform accurate photometry with modest telescopes. Is there any reason to still count photons? This paper discusses some of the strengths of current photon counting technology, particularly relating to the search for fast optical transients. Technology advances in counters and photomultiplier modules are briefly mentioned. Illustrative data are presented including FFT analysis of bright star photometry and a technique for finding optical pulses in a large file of noisy data. This latter technique is shown to enable the discovery of a possible optical flare on the polar variable AM Her.

  17. Kentucky Kids Count 2001 County Data Book: Families Count.

    ERIC Educational Resources Information Center

    Salley, Valerie

    This Kids Count county data book is the eleventh in a series to measure the well-being of Kentucky's children and focuses on the vital role that families play in ensuring their children's success. Included at the beginning of this document is an executive summary of the databook providing an overview of the statewide data for six child and family…

  18. Effects of crossover hydrogen on platinum dissolution and agglomeration

    NASA Astrophysics Data System (ADS)

    Cheng, Tommy T. H.; Rogers, Erin; Young, Alan P.; Ye, Siyu; Colbow, Vesna; Wessel, Silvia

    2011-10-01

    The durability of catalysts in the polymer-electrolyte membrane fuel cell (PEMFC) is identified as a critical limiting factor for wide commercialization of fuel cells. Even though much progress has been made in understanding the degradation mechanisms, the phenomena of Pt dissolution and agglomeration and their contributing factors are not fully understood. In the present investigation, the effects of crossover hydrogen on Pt degradation are studied using an accelerated stress test (AST). The end-of-test (EOT) membrane-electrode-assemblies (MEAs) were characterized by X-ray diffraction (XRD), scanning-electron microscopy (SEM), and energy-dispersive X-ray (EDX). The results provided mechanistic understanding of Pt dissolution and agglomeration: Pt growth and agglomeration were found to be less severe with more crossover hydrogen due likely to the chemical reduction of Pt oxides by crossover hydrogen and the subsequently decrease in the amount of Pt ions formed via the oxide pathway.

  19. Influence analysis on crossover design experiment in bioequivalence studies.

    PubMed

    Huang, Yufen; Ke, Bo-Shiang

    2014-01-01

    Crossover designs are commonly used in bioequivalence studies. However, the results can be affected by some outlying observations, which may lead to the wrong decision on bioequivalence. Therefore, it is essential to investigate the influence of aberrant observations. Chow and Tse in 1990 discussed this issue by considering the methods based on the likelihood distance and estimates distance. Perturbation theory provides a useful tool for the sensitivity analysis on statistical models. Hence, in this paper, we develop the influence functions via the perturbation scheme proposed by Hampel as an alternative approach on the influence analysis for a crossover design experiment. Moreover, the comparisons between the proposed approach and the method proposed by Chow and Tse are investigated. Two real data examples are provided to illustrate the results of these approaches. Our proposed influence functions show excellent performance on the identification of outlier/influential observations and are suitable for use with small sample size crossover designs commonly used in bioequivalence studies.

  20. Self-affine crossover length in a layered silicate deposit.

    PubMed

    Fossum, J O; Bergene, H H; Hansen, Alex; O'Rourke, B; Manificat, G

    2004-03-01

    Self-affine dehydrated colloidal deposits on fresh mica surfaces of the synthetic layered silicate 2:1 smectite clay laponite have been studied by means of atomic force microscopy (AFM). AFM images of these prepared assemblies of sol and gel aggregates have been analyzed both by means of standard AFM Fourier software and a wavelet method. The deposited surfaces show a persistence to antipersistent crossover with a clay concentration dependent crossover length. It is concluded that the crossover length is associated with aggregate size, and further that the persistent roughness at small length scales signals near compact clusters of fractal dimension three, whereas the antipersistent roughness at large length scales signals a sedimentation process.

  1. Self-affine crossover length in a layered silicate deposit

    NASA Astrophysics Data System (ADS)

    Fossum, J. O.; Bergene, H. H.; Hansen, Alex; O'Rourke, B.; Manificat, G.

    2004-03-01

    Self-affine dehydrated colloidal deposits on fresh mica surfaces of the synthetic layered silicate 2:1 smectite clay laponite have been studied by means of atomic force microscopy (AFM). AFM images of these prepared assemblies of sol and gel aggregates have been analyzed both by means of standard AFM Fourier software and a wavelet method. The deposited surfaces show a persistence to antipersistent crossover with a clay concentration dependent crossover length. It is concluded that the crossover length is associated with aggregate size, and further that the persistent roughness at small length scales signals near compact clusters of fractal dimension three, whereas the antipersistent roughness at large length scales signals a sedimentation process.

  2. Dimensional crossover of the dephasing time in disordered mesoscopic rings

    NASA Astrophysics Data System (ADS)

    Treiber, M.; Yevtushenko, O. M.; Marquardt, F.; von Delft, J.; Lerner, I. V.

    2009-11-01

    We study dephasing by electron interactions in a small disordered quasi-one-dimensional (1D) ring weakly coupled to leads. We use an influence functional for quantum Nyquist noise to describe the crossover for the dephasing time τφ(T) from diffusive or ergodic 1D (τφ-1∝T2/3,T1) to zero-dimensional (0D) behavior (τφ-1∝T2) as T drops below the Thouless energy. The crossover to 0D, predicted earlier for two-dimensional and three-dimensional systems, has so far eluded experimental observation. The ring geometry holds promise of meeting this long-standing challenge, since the crossover manifests itself not only in the smooth part of the magnetoconductivity but also in the amplitude of Altshuler-Aronov-Spivak oscillations. This allows signatures of dephasing in the ring to be cleanly extracted by filtering out those of the leads.

  3. Optimization of simultaneous tritium–radiocarbon internal gas proportional counting

    SciTech Connect

    Bonicalzi, R. M.; Aalseth, C. E.; Day, A. R.; Hoppe, E. W.; Mace, E. K.; Moran, J. J.; Overman, C. T.; Panisko, M. E.; Seifert, A.

    2016-03-01

    Specific environmental applications can benefit from dual tritium and radiocarbon measurements in a single compound. Assuming typical environmental levels, it is often the low tritium activity relative to the higher radiocarbon activity that limits the dual measurement. In this paper, we explore the parameter space for a combined tritium and radiocarbon measurement using a methane sample mixed with an argon fill gas in low-background proportional counters of a specific design. We present an optimized methane percentage, detector fill pressure, and analysis energy windows to maximize measurement sensitivity while minimizing count time. The final optimized method uses a 9-atm fill of P35 (35% methane, 65% argon), and a tritium analysis window from 1.5 to 10.3 keV, which stops short of the tritium beta decay endpoint energy of 18.6 keV. This method optimizes tritium counting efficiency while minimizing radiocarbon beta decay interference.

  4. Optimization of simultaneous tritium-radiocarbon internal gas proportional counting

    NASA Astrophysics Data System (ADS)

    Bonicalzi, R. M.; Aalseth, C. E.; Day, A. R.; Hoppe, E. W.; Mace, E. K.; Moran, J. J.; Overman, C. T.; Panisko, M. E.; Seifert, A.

    2016-03-01

    Specific environmental applications can benefit from dual tritium and radiocarbon measurements in a single compound. Assuming typical environmental levels, it is often the low tritium activity relative to the higher radiocarbon activity that limits the dual measurement. In this paper, we explore the parameter space for a combined tritium and radiocarbon measurement using a natural methane sample mixed with an argon fill gas in low-background proportional counters of a specific design. We present an optimized methane percentage, detector fill pressure, and analysis energy windows to maximize measurement sensitivity while minimizing count time. The final optimized method uses a 9-atm fill of P35 (35% methane, 65% argon), and a tritium analysis window from 1.5 to 10.3 keV, which stops short of the tritium beta decay endpoint energy of 18.6 keV. This method optimizes tritium-counting efficiency while minimizing radiocarbon beta-decay interference.

  5. Full-counting statistics of time-dependent conductors

    NASA Astrophysics Data System (ADS)

    Benito, Mónica; Niklas, Michael; Kohler, Sigmund

    2016-11-01

    We develop a scheme for the computation of the full-counting statistics of transport described by Markovian master equations with an arbitrary time dependence. It is based on a hierarchy of generalized density operators, where the trace of each operator yields one cumulant. This direct relation offers a better numerical efficiency than the equivalent number-resolved master equation. The proposed method is particularly useful for conductors with an elaborate time dependence stemming, e.g., from pulses or combinations of slow and fast parameter switching. As a test bench for the evaluation of the numerical stability, we consider time-independent problems for which the full-counting statistics can be computed by other means. As applications, we study cumulants of higher order for two time-dependent transport problems of recent interest, namely steady-state coherent transfer by adiabatic passage (CTAP) and Landau-Zener-Stückelberg-Majorana (LZSM) interference in an open double quantum dot.

  6. Counting Multiplicity over Infinite Alphabets

    NASA Astrophysics Data System (ADS)

    Manuel, Amaldev; Ramanujam, R.

    In the theory of automata over infinite alphabets, a central difficulty is that of finding a suitable compromise between expressiveness and algorithmic complexity. We propose an automaton model where we count the multiplicity of data values on an input word. This is particularly useful when such languages represent behaviour of systems with unboundedly many processes, where system states carry such counts as summaries. A typical recognizable language is: “every process does at most k actions labelled a”. We show that emptiness is elementarily decidable, by reduction to the covering problem on Petri nets.

  7. Subcritical-supercritical bifurcation crossover in directional solidification

    SciTech Connect

    Liu, D.; Williams, L.; Cummins, H. )

    1994-12-01

    The Mullins-Sekerka planar-cellular instability in directional solidification should be subcritical when the partition coefficient [ital k][lt]0.45 and latent heat is ignored. However, Merchant and Davis [Phys. Rev. Lett. [bold 63], 573 (1989)] predicted that as the solute concentration is reduced, the increasingly important thermal diffusion field would lead to a crossover from a subcritical to a supercritical bifurcation. We have performed directional solidification experiments on a series of succinonitrile samples containing different concentrations of Coumarin 152, and have found preliminary evidence for the predicted crossover at a concentration [ital C][sub [ital t

  8. Counting a Culture of Mealworms

    ERIC Educational Resources Information Center

    Ashbrook, Peggy

    2007-01-01

    Math is not the only topic that will be discussed when young children are asked to care for and count "mealworms," a type of insect larvae (just as caterpillars are the babies of butterflies, these larvae are babies of beetles). The following activity can take place over two months as the beetles undergo metamorphosis from larvae to adults. As the…

  9. KIDS COUNT Data Brief, 2009

    ERIC Educational Resources Information Center

    Annie E. Casey Foundation, 2009

    2009-01-01

    This 2009 KIDS COUNT Data Brief features highlights of the enhanced, mobile-friendly Data Center; data on the 10 key indicators of child well-being for all U.S. states, the District of Columbia, and many cities, counties, and school districts; and a summary of this year's essay, which calls for improvements to the nation's ability to design and…

  10. Meal Counting and Claiming Manual.

    ERIC Educational Resources Information Center

    Food and Nutrition Service (USDA), Washington, DC.

    This manual contains information about the selection and implementation of a meal counting and claiming system for the National School Lunch Program (NSLP) and the School Breakfast Program (BSP). Federal reimbursement is provided for each meal that meets program requirements and is served to an eligible student. Part 1 explains the six elements of…

  11. KIDS COUNT New Hampshire, 2000.

    ERIC Educational Resources Information Center

    Shemitz, Elllen, Ed.

    This Kids Count report presents statewide trends in the well-being of New Hampshire's children. The statistical report is based on 22 indicators of child well-being in 5 interrelated areas: (1) children and families (including child population, births, children living with single parent, and children experiencing parental divorce); (2) economic…

  12. Wyoming Kids Count Factbook, 1997.

    ERIC Educational Resources Information Center

    Wyoming Kids Count, Cheyenne.

    This Kids Count factbook details statewide trends in the well-being of Wyoming's children. The 1997 report has been expanded to include detailed information on the status of children by categories of welfare, health, and education. The first part of the factbook documents trends by county for 15 indicators: (1) poverty and population; (2)…

  13. Wiskids Count Data Book, 2003.

    ERIC Educational Resources Information Center

    Cranley, M. Martha; Bianchi, J. P.; Eleson, Charity; Hall, Linda; Jacobson, Bob; Jackson, Kristin; Peacock, Jon

    This WisKids Count data book provides a statistical portrait of the well-being of Wisconsin's children. In addition to demographic data indicating changing communities, the indicators and data are organized into five overarching goals: (1) Healthy Families and Children Thrive, including births to single women, infant deaths, and health care…

  14. Shakespeare Live! and Character Counts.

    ERIC Educational Resources Information Center

    Brookshire, Cathy A.

    This paper discusses a live production of Shakespeare's "Macbeth" (in full costume but with no sets) for all public middle school and high school students in Harrisonburg and Rockingham, Virginia. The paper states that the "Character Counts" issues that are covered in the play are: decision making, responsibility and…

  15. South Carolina Kids Count, 2001.

    ERIC Educational Resources Information Center

    Holmes, A. Baron

    This Kids Count report examines statewide trends in the well-being of South Carolina's children. The statistical portrait is based on 42 indicators in the areas of demographics, family, economic status, health, readiness and early school performance, scholastic achievement, and adolescent risk behaviors. The indicators are: (1) population; (2)…

  16. South Carolina Kids Count, 2000.

    ERIC Educational Resources Information Center

    Holmes, A. Baron

    This Kids Count report examines statewide trends in the well-being of South Carolina's children. The statistical portrait is based on 41 indicators in the areas of demographics, family, economic status, health, readiness and early school performance, scholastic achievement, and adolescent risk behaviors. The indicators are: (1) population; (2)…

  17. Kids Count in Colorado! 2003.

    ERIC Educational Resources Information Center

    Boeke, Kaye

    This Kids Count report examines state, county, and regional trends in the well-being of Colorado's children. The first part of the report is presented in four chapters. Chapter 1 includes findings regarding the increasing diversity of the child population, linguistic isolation, the impact of parental unemployment, child poverty, and the affordable…

  18. Complete Blood Count (For Parents)

    MedlinePlus

    ... If the platelet count is too low, a person can be in danger of bleeding in any part of the body. The CBC can also test for loss of blood, abnormalities in the production or destruction of blood cells, acute and chronic infections, allergies, and problems with ...

  19. Maryland KIDS COUNT Factbook, 1999.

    ERIC Educational Resources Information Center

    Advocates for Children and Youth, Baltimore, MD.

    This Kids Count factbook is the fifth to examine statewide and county trends in the well-being of Maryland's children. The statistical portrait is based on indicators in the domains of economic well-being, good health, safety, and preparing for adulthood. The 16 indicators are: (1) child poverty; (2) child support; (3) births to teens; (4) low…

  20. Oklahoma Kids Count Factbook, 2002.

    ERIC Educational Resources Information Center

    Ingraham, Sandy

    This Kids Count Factbook details county and statewide trends in the well-being of children in Oklahoma. The statistical portrait is based on seven indicators or benchmarks of child well-being: (1) low birthweight infants; (2) infant mortality; (3) births to young teens; (4) child abuse and neglect; (5) child and teen death; (6) high school…

  1. Maryland Kids Count Factbook, 2001.

    ERIC Educational Resources Information Center

    Advocates for Children and Youth, Baltimore, MD.

    This 7th annual Kids Count Factbook provides information on trends in the well-being of children in Maryland and its 24 jurisdictions. The statistical portrait is based on 18 indicators of well-being: (1) low birth-weight infants; (2) infant mortality; (3) early prenatal care; (4) binge drinking; (5) child deaths; (6) child injury rate; (7) grade…

  2. Verbal Counting in Bilingual Contexts

    ERIC Educational Resources Information Center

    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…

  3. Teaching Emotionally Disturbed Students to Count Feelings.

    ERIC Educational Resources Information Center

    Bartels, Cynthia S.; Calkin, Abigail B.

    The paper describes a program to teach high school students with emotional and behavior problems to count their feelings, thereby improving their self concept. To aid in instruction, a hierarchy was developed which involved four phases: counting tasks completed and tasks not completed, counting independent actions in class, counting perceptions of…

  4. Optical interference with digital holograms

    NASA Astrophysics Data System (ADS)

    Gossman, David; Perez-Garcia, Benjamin; Hernandez-Aranda, Raul I.; Forbes, Andrew

    2016-07-01

    In 1804, Thomas Young reported the observation of fringes in the intensity of light, and attributed it to the concept of interference between coherent sources. In this paper, we revisit this famous experiment and show how it can easily be demonstrated with digital holography. We look closely at the concept of interference with light and ask, "fringes in what?" We then show that depending on how light interferes, fringe patterns in observables other than intensity can be seen. We explain this conceptually and demonstrate it experimentally. We provide a holistic approach to the topic, aided by modern laboratory practices for a straightforward demonstration of the underlying physics.

  5. Predictive Model Assessment for Count Data

    DTIC Science & Technology

    2007-09-05

    critique count regression models for patent data, and assess the predictive performance of Bayesian age-period-cohort models for larynx cancer counts...the predictive performance of Bayesian age-period-cohort models for larynx cancer counts in Germany. We consider a recent suggestion by Baker and...Figure 5. Boxplots for various scores for patent data count regressions. 11 Table 1 Four predictive models for larynx cancer counts in Germany, 1998–2002

  6. 47 CFR 87.425 - Interference.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Airport Control Tower Stations § 87.425 Interference. Control towers and RCOs must not cause harmful interference to control towers or RCOs at adjacent airports. If interference between adjacent control towers...

  7. 47 CFR 87.425 - Interference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Airport Control Tower Stations § 87.425 Interference. Control towers and RCOs must not cause harmful interference to control towers or RCOs at adjacent airports. If interference between adjacent control towers...

  8. 47 CFR 87.425 - Interference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Airport Control Tower Stations § 87.425 Interference. Control towers and RCOs must not cause harmful interference to control towers or RCOs at adjacent airports. If interference between adjacent control towers...

  9. 47 CFR 87.425 - Interference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Airport Control Tower Stations § 87.425 Interference. Control towers and RCOs must not cause harmful interference to control towers or RCOs at adjacent airports. If interference between adjacent control towers...

  10. 47 CFR 87.425 - Interference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Airport Control Tower Stations § 87.425 Interference. Control towers and RCOs must not cause harmful interference to control towers or RCOs at adjacent airports. If interference between adjacent control towers...

  11. Crossover Improvement for the Genetic Algorithm in Information Retrieval.

    ERIC Educational Resources Information Center

    Vrajitoru, Dana

    1998-01-01

    In information retrieval (IR), the aim of genetic algorithms (GA) is to help a system to find, in a huge documents collection, a good reply to a query expressed by the user. Analysis of phenomena seen during the implementation of a GA for IR has led to a new crossover operation, which is introduced and compared to other learning methods.…

  12. 50 CFR 660.120 - Trawl fishery-crossover provisions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Trawl fishery-crossover provisions. 660.120 Section 660.120 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OFF WEST COAST STATES West...

  13. Design and analysis of crossover trials for absorbing binary endpoints.

    PubMed

    Nason, Martha; Follmann, Dean

    2010-09-01

    The crossover is a popular and efficient trial design used in the context of patient heterogeneity to assess the effect of treatments that act relatively quickly and whose benefit disappears with discontinuation. Each patient can serve as her own control as within-individual treatment and placebo responses are compared. Conventional wisdom is that these designs are not appropriate for absorbing binary endpoints, such as death or HIV infection. We explore the use of crossover designs in the context of these absorbing binary endpoints and show that they can be more efficient than the standard parallel group design when there is heterogeneity in individuals' risks. We also introduce a new two-period design where first period "survivors" are rerandomized for the second period. This design combines the crossover design with the parallel design and achieves some of the efficiency advantages of the crossover design while ensuring that the second period groups are comparable by randomization. We discuss the validity of the new designs and evaluate both a mixture model and a modified Mantel-Haenszel test for inference. The mixture model assumes no carryover or period effects while the Mantel-Haenszel approach conditions out period effects. Simulations are used to compare the different designs and an example is provided to explore practical issues in implementation.

  14. The critical crossover at the n-hexane-water interface

    SciTech Connect

    Tikhonov, A. M.

    2010-06-15

    According to estimates of the parameters of the critical crossover in monolayers of long-chain alcohol molecules adsorbed at the n-hexane-water interface, all systems in which this phenomenon is observed are characterized by the same value of the critical exponent {nu} {approx} 1.8.

  15. Interference problems for nongeostationary satellites

    NASA Technical Reports Server (NTRS)

    Sollfrey, W.

    1984-01-01

    The interference problems faced by nongeostationary satellites may be of major significance. A general discussion indicates the scope of the problems and describes several configurations of importance. Computer programs are described, which are employed by NASA/JPL and the U.S. Air Force Satellite Control Facility to provide interference-free scheduling of commands and data transmission. Satellite system mission planners are not concerned with the precise prediction of interference episodes, but rather with the expected total amount of interference, the mean and maximum duration of events, and the mean spacing between episodes. The procedures in the theory of probability developed by the author which permit calculation of such quantities are described and applied to several real cases. It may be anticipated that the problems will become steadily worse in the future as more and more data transmissions attempt to occupy the same frequency band.

  16. RNA interference: unraveling a mystery.

    PubMed

    Montgomery, Mary K

    2006-12-01

    Andrew Fire and Craig Mello have won the Nobel Prize in Medicine or Physiology for their discovery of RNA interference. Mary K. Montgomery, then a postdoc in the Fire laboratory, participated in some of the key experiments.

  17. Interference Colors in Thin Films.

    ERIC Educational Resources Information Center

    Armstrong, H. L.

    1979-01-01

    Explains interference colors in thin films as being due to the removal, or considerable reduction, of a certain color by destructive inteference that results in the complementary color being seen. (GA)

  18. Retrieval interference in sentence comprehension

    PubMed Central

    Van Dyke, Julie A.; McElree, Brian

    2007-01-01

    The role of interference effects in sentence processing has recently begun to receive attention, however whether these effects arise during encoding or retrieval remains unclear. This paper draws on basic memory research to help distinguish these explanations and reports data from an experiment that manipulates the possibility for retrieval interference while holding encoding conditions constant. We found clear support for the principle of cue-overload, wherein cues available at retrieval cannot uniquely distinguish among competitors, thus giving rise to interference effects. We discuss the data in relation to a cue-based parsing framework (Van Dyke & Lewis, 2003) and other interference effects observed in sentence processing (e.g., Gordon, Hendrick, & Johnson, 2001, 2004). We conclude from the available data that the memory system that subserves language comprehension operates according to similar principles as memory in other domains. PMID:18209744

  19. Stimulus Structure, Discrimination, and Interference

    ERIC Educational Resources Information Center

    Runquist, Willard N.

    1975-01-01

    The general purpose of this experiment was to determine whether differences in stimulus discrimination, as determined by the MIR (missing-item recognition) test, are correlated with interference in recall, as demanded by the discriminative coding hypothesis. (Author/RK)

  20. Evaluate interference in digital channels

    NASA Technical Reports Server (NTRS)

    Davarian, F.; Sumida, J.

    1985-01-01

    Any future mobile satellite service (MSS) which is to provide simultaneous mobile communications for a large number of users will have to make very efficient use of the spectrum. As the spectrum available for an MSS is limited, the system's channels should be packed as closely together as possible, with minimum-width guard bands. In addition the employment of frequency reuse schemes is an important factor. Difficulties regarding these solutions are related to the introduction of interference in the link. A balance must be achieved between the competing aims of spectrum conservation and low interference. While the interference phenomenon in narrowband FM voice channels is reasonably well understood, very little effort, however, has been devoted to the problem in digital radios. Attention is given to work, which illuminates the effects of cochannel and adjacent channel interference on digital FM (FSK) radios.

  1. Altered Crossover Distribution and Frequency in Spermatocytes of Infertile Men with Azoospermia

    PubMed Central

    Ren, He; Ferguson, Kyle; Kirkpatrick, Gordon; Vinning, Tanya; Chow, Victor; Ma, Sai

    2016-01-01

    During meiosis, homologous chromosomes pair to facilitate the exchange of DNA at crossover sites along the chromosomes. The frequency and distribution of crossover formation are tightly regulated to ensure the proper progression of meiosis. Using immunofluorescence techniques, our group and others have studied the meiotic proteins in spermatocytes of infertile men, showing that this population displays a reduced frequency of crossovers compared to fertile men. An insufficient number of crossovers is thought to promote chromosome missegregation, in which case the faulty cell may face meiotic arrest or contribute to the production of aneuploid sperm. Increasing evidence in model organisms has suggested that the distribution of crossovers may also be important for proper chromosome segregation. In normal males, crossovers are shown to be rare near centromeres and telomeres, while frequent in subtelomeric regions. Our study aims to characterize the crossover distribution in infertile men with non-obstructive (NOA) and obstructive azoospermia (OA) along chromosomes 13, 18 and 21. Eight of the 16 NOA men and five of the 21 OA men in our study displayed reduced crossover frequency compared to control fertile men. Seven NOA men and nine OA men showed altered crossover distributions on at least one of the chromosome arms studied compared to controls. We found that although both NOA and OA men displayed altered crossover distributions, NOA men may be at a higher risk of suffering both altered crossover frequencies and distributions compared to OA men. Our data also suggests that infertile men display an increase in crossover formation in regions where they are normally inhibited, specifically near centromeres and telomeres. Finally, we demonstrated a decrease in crossovers near subtelomeres, as well as increased average crossover distance to telomeres in infertile men. As telomere-guided mechanisms are speculated to play a role in crossover formation in subtelomeres, future

  2. Multipolar interference effects in nanophotonics.

    PubMed

    Liu, Wei; Kivshar, Yuri S

    2017-03-28

    Scattering of electromagnetic waves by an arbitrary nanoscale object can be characterized by a multipole decomposition of the electromagnetic field that allows one to describe the scattering intensity and radiation pattern through interferences of dominating multipole modes excited. In modern nanophotonics, both generation and interference of multipole modes start to play an indispensable role, and they enable nanoscale manipulation of light with many related applications. Here, we review the multipolar interference effects in metallic, metal-dielectric and dielectric nanostructures, and suggest a comprehensive view on many phenomena involving the interferences of electric, magnetic and toroidal multipoles, which drive a number of recently discussed effects in nanophotonics such as unidirectional scattering, effective optical antiferromagnetism, generalized Kerker scattering with controlled angular patterns, generalized Brewster angle, and non-radiating optical anapoles. We further discuss other types of possible multipolar interference effects not yet exploited in the literature and envisage the prospect of achieving more flexible and advanced nanoscale control of light relying on the concepts of multipolar interference through full phase and amplitude engineering.This article is part of the themed issue 'New horizons for nanophotonics'.

  3. Geodetic constraints from multi-beam laser altimeter crossovers

    NASA Astrophysics Data System (ADS)

    Mazarico, Erwan; Neumann, G. A.; Rowlands, D. D.; Smith, D. E.

    2010-06-01

    The round-trip travel time measurements made by spacecraft laser altimeters are primarily used to construct topographic maps of the target body. The accuracy of the calculated bounce point locations of the laser pulses depends on the quality of the spacecraft trajectory reconstruction. The trajectory constraints from Doppler and range radio tracking data can be supplemented by altimetric “crossovers”, to greatly improve the reconstruction of the spacecraft trajectory. Crossovers have been used successfully in the past (e.g., Mars Orbiter Laser Altimeter on Mars Global Surveyor), but only with single-beam altimeters. The same algorithms can be used with a multi-beam laser altimeter, but we present a method using the unique cross-track topographic information present in the multi-beam data. Those crossovers are especially adapted to shallow (small angle) intersections, as the overlapping area is large, reducing the inherent ambiguities of single-beam data in that situation. We call those “swath crossovers”. They prove particularly useful in the case of polar-orbiting spacecraft over slowly rotating bodies, because all the non-polar crossovers have small intersection angles. To demonstrate this method, we perform a simplified simulation based on the Lunar Reconnaissance Orbiter (LRO) and its five-beam Lunar Orbiter Laser Altimeter. We show that swath crossovers over one lunar month can independently, from geometry alone, recover the imposed orbital perturbations with great accuracy (5 m horizontal, < 1 m vertical, about one order of magnitude smaller than the imposed perturbations). We also present new types of constraints that can be derived from the swath crossovers, and designed to be used in a precision orbit determination setup. In future work, we will use such multi-beam altimetric constraints with data from LRO.

  4. Bayesian Kernel Mixtures for Counts.

    PubMed

    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.

  5. [Platelet count in the cat].

    PubMed

    Moritz, A; Hoffmann, C

    1997-11-01

    The technique of collecting blood samples is primarily responsible for the appearance of platelet-agglomeration in cats. Blood obtained by the conventional way ("one syringe technology", drips of blood) caused in 52% of the cases an activation of the large and therefore active thrombocytes however. Rejection of the first 2-5 ml blood for the platelet count ("two syringe technology") reduced the rate of platelet-agglomeration significantly. No big differences in platelet-agglomeration were found with regard to the place used for collecting blood (V. cephalica antebrachii/V. jugularis). Platelet-agglutination was observed with Li-Heparin, K-EDTA, Na-Citrat or ACD anticoagulated blood samples. Citrat (Na-Citrat, ACD) seemed to have a stabilizing effect on feline thrombocytes as has been described for human thrombocytes. The platelet count in cats should be performed within 30 minutes.

  6. What's Mine Is Yours: The Crossover of Day-Specific Self-Esteem

    ERIC Educational Resources Information Center

    Neff, Angela; Sonnentag, Sabine; Niessen, Cornelia; Unger, Dana

    2012-01-01

    This diary study examines the daily crossover of self-esteem within working couples. By integrating self-esteem research into the crossover framework, we hypothesized that the day-specific self-esteem experienced by one partner after work crosses over to the other partner. Furthermore, we proposed that this daily crossover process is moderated by…

  7. 49 CFR 236.203 - Hand operated crossover between main tracks; protection.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Hand operated crossover between main tracks..., AND APPLIANCES Automatic Block Signal Systems Standards § 236.203 Hand operated crossover between main tracks; protection. At hand-operated crossover between main tracks, protection shall be provided by...

  8. 49 CFR 236.203 - Hand operated crossover between main tracks; protection.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Hand operated crossover between main tracks..., AND APPLIANCES Automatic Block Signal Systems Standards § 236.203 Hand operated crossover between main tracks; protection. At hand-operated crossover between main tracks, protection shall be provided by...

  9. 49 CFR 236.203 - Hand operated crossover between main tracks; protection.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Hand operated crossover between main tracks..., AND APPLIANCES Automatic Block Signal Systems Standards § 236.203 Hand operated crossover between main tracks; protection. At hand-operated crossover between main tracks, protection shall be provided by...

  10. Counting Heron Triangles with Constraints

    DTIC Science & Technology

    2013-01-25

    A3 INTEGERS 13 (2013) COUNTING HERON TRIANGLES WITH CONSTRAINTS Pantelimon Stănică Applied Mathematics, Naval Postgraduate School, Monterey...12, Revised: 10/12/12, Accepted: 1/13/13, Published: 1/25/13 Abstract Heron triangles have the property that all three of their sides as well as their...area are positive integers. In this paper, we give some estimates for the number of Heron triangles with two of their sides fixed. We provide a

  11. Manual and automated reticulocyte counts.

    PubMed

    Simionatto, Mackelly; de Paula, Josiane Padilha; Chaves, Michele Ana Flores; Bortoloso, Márcia; Cicchetti, Domenic; Leonart, Maria Suely Soares; do Nascimento, Aguinaldo José

    2010-12-01

    Manual reticulocyte counts were examined under light microscopy, using the property whereby supravital stain precipitates residual ribosomal RNA versus the automated flow methods, with the suggestion that in the latter there is greater precision and an ability to determine both mature and immature reticulocyte fractions. Three hundred and forty-one venous blood samples of patients were analyzed of whom 224 newborn and the rest adults; 51 males and 66 females, with ages between 0 and 89 years, as part of the laboratory routine for hematological examinations at the Clinical Laboratory of the Hospital Universitário do Oeste do Paraná. This work aimed to compare manual and automated methodologies for reticulocyte countings and evaluate random and systematic errors. The results obtained showed that the difference between the two methods was very small, with an estimated 0·4% systematic error and 3·9% random error. Thus, it has been confirmed that both methods, when well conducted, can reflect precisely the reticulocyte counts for adequate clinical use.

  12. The MIC photon counting detector

    NASA Astrophysics Data System (ADS)

    Fordham, J. L. A.; Bone, D. A.; Oldfield, M. K.; Bellis, J. G.; Norton, T. J.

    1992-12-01

    The MIC (Microchannel plate Intensified CCD (Charge Coupled Device)) detector is an advanced performance Micro Channel Plate (MCP) intensified CCD photon counting detector developed for high resolution, high dynamic range, astronomical applications. The heart of the detector is an MCP intensifier developed specifically for photon counting applications. The maximum detector format is 3072 by 2304 pixels. The measured resolution of the detector system is 18 micrometers FWHM at 490 nm. The detector is linear to approximately 1,000,000 events/detector area/sec on a flat field and linear to count rates up to 200 events/object/s on star images. Two versions of the system have been developed. The first for ground based astronomical applications based around a 40 mm diameter intensifier, was proven in trials at a number of large optical telescopes. The second, specifically for the ESA X-Ray Multi Mirror Mission (XMM), where the MIC has been accepted as the blue detector for the incorporated Optical Monitor (OM). For the XMM-OM, the system is based around a 25 mm diameter intensifier. At present, under development, is a 75 mm diameter version of the detector which will have a maximum format of 6144 by 4608 pixels. Details of the MIC detector and its performance are presented.

  13. Approximate Counting of Graphical Realizations.

    PubMed

    Erdős, Péter L; Kiss, Sándor Z; Miklós, István; Soukup, Lajos

    2015-01-01

    In 1999 Kannan, Tetali and Vempala proposed a MCMC method to uniformly sample all possible realizations of a given graphical degree sequence and conjectured its rapidly mixing nature. Recently their conjecture was proved affirmative for regular graphs (by Cooper, Dyer and Greenhill, 2007), for regular directed graphs (by Greenhill, 2011) and for half-regular bipartite graphs (by Miklós, Erdős and Soukup, 2013). Several heuristics on counting the number of possible realizations exist (via sampling processes), and while they work well in practice, so far no approximation guarantees exist for such an approach. This paper is the first to develop a method for counting realizations with provable approximation guarantee. In fact, we solve a slightly more general problem; besides the graphical degree sequence a small set of forbidden edges is also given. We show that for the general problem (which contains the Greenhill problem and the Miklós, Erdős and Soukup problem as special cases) the derived MCMC process is rapidly mixing. Further, we show that this new problem is self-reducible therefore it provides a fully polynomial randomized approximation scheme (a.k.a. FPRAS) for counting of all realizations.

  14. Approximate Counting of Graphical Realizations

    PubMed Central

    2015-01-01

    In 1999 Kannan, Tetali and Vempala proposed a MCMC method to uniformly sample all possible realizations of a given graphical degree sequence and conjectured its rapidly mixing nature. Recently their conjecture was proved affirmative for regular graphs (by Cooper, Dyer and Greenhill, 2007), for regular directed graphs (by Greenhill, 2011) and for half-regular bipartite graphs (by Miklós, Erdős and Soukup, 2013). Several heuristics on counting the number of possible realizations exist (via sampling processes), and while they work well in practice, so far no approximation guarantees exist for such an approach. This paper is the first to develop a method for counting realizations with provable approximation guarantee. In fact, we solve a slightly more general problem; besides the graphical degree sequence a small set of forbidden edges is also given. We show that for the general problem (which contains the Greenhill problem and the Miklós, Erdős and Soukup problem as special cases) the derived MCMC process is rapidly mixing. Further, we show that this new problem is self-reducible therefore it provides a fully polynomial randomized approximation scheme (a.k.a. FPRAS) for counting of all realizations. PMID:26161994

  15. Skating crossovers on a motorized flywheel: a preliminary experimental design to test effect on speed and on crossovers.

    PubMed

    Smith, Aynsley M; Krause, David A; Stuart, Michael J; Montelpare, William J; Sorenson, Matthew C; Link, Andrew A; Gaz, Daniel V; Twardowski, Casey P; Larson, Dirk R; Stuart, Michael B

    2013-12-01

    Ice hockey requires frequent skater crossovers to execute turns. Our investigation aimed to determine the effectiveness of training crossovers on a motorized, polyethylene high-resistance flywheel. We hypothesized that high school hockey players training on the flywheel would perform as well as their peers training on ice. Participants were 23 male high-school hockey players (age 15-19 years). The study used an experimental prospective design to compare players who trained for 9 sessions on the 22-foot flywheel with players who trained for 9 sessions on a similarly sized on-ice circle. Both groups were compared with control subjects who were randomly selected from the same participant pool as those training on ice. All players were tested before and after their 3-week training regimens, and control subjects were asked to not practice crossovers between testing. Group 1 trained in a hockey training facility housing the flywheel, and group 2 trained in the ice hockey arena where testing occurred. Primary outcome measures tested in both directions were: (a) speed (time in seconds) required to skate crossovers for 3 laps of a marked face-off circle, (b) cadence of skating crossovers on the similarly sized circles, and (c) a repeat interval speed test, which measures anaerobic power. No significant changes were found between groups in on-ice testing before and after training. Among the group 1 players, 7 of 8 believed they benefited from flywheel training. Group 2 players, who trained on ice, did not improve performance significantly over group 1 players. Despite the fact that no significant on-ice changes in performance were observed in objective measures, players who trained on the flywheel subjectively reported that the flywheel is an effective cost-effective alternative to training on ice. This is a relevant finding when placed in context with limited availability of on-ice training.

  16. Detection of retinitis pigmentosa by differential interference contrast microscopy.

    PubMed

    Oh, Juyeong; Kim, Seok Hwan; Kim, Yu Jeong; Lee, Hyunho; Cho, Joon Hyong; Cho, Young Ho; Kim, Chul-Ki; Lee, Taik Jin; Lee, Seok; Park, Ki Ho; Yu, Hyeong Gon; Lee, Hyuk-Jae; Jun, Seong Chan; Kim, Jae Hun

    2014-01-01

    Differential interference contrast microscopy is designed to image unstained and transparent specimens by enhancing the contrast resulting from the Nomarski prism-effected optical path difference. Retinitis pigmentosa, one of the most common inherited retinal diseases, is characterized by progressive loss of photoreceptors. In this study, Differential interference contrast microscopy was evaluated as a new and simple application for observation of the retinal photoreceptor layer and retinitis pigmentosa diagnostics and monitoring. Retinal tissues of Royal College of Surgeons rats and retinal-degeneration mice, both well-established animal models for the disease, were prepared as flatmounts and histological sections representing different elapsed times since the occurrence of the disease. Under the microscopy, the retinal flatmounts showed that the mosaic pattern of the photoreceptor layer was irregular and partly collapsed at the early stage of retinitis pigmentosa, and, by the advanced stage, amorphous. The histological sections, similarly, showed thinning of the photoreceptor layer at the early stage and loss of the outer nuclear layer by the advanced stage. To count and compare the number of photoreceptors in the normal and early-retinitis pigmentosa-stage tissues, an automated cell-counting program designed with MATLAB, a numerical computing language, using a morphological reconstruction method, was applied to the differential interference contrast microscopic images. The number of cells significantly decreased, on average, from 282 to 143 cells for the Royal College of Surgeons rats and from 255 to 170 for the retinal-degeneration mouse. We successfully demonstrated the potential of the differential interference contrast microscopy technique's application to the diagnosis and monitoring of RP.

  17. Crossover between Weak Antilocalization and Weak Localization of Bulk States in Ultrathin Bi2Se3 Films

    NASA Astrophysics Data System (ADS)

    Wang, Huichao; Liu, Haiwen; Chang, Cui-Zu; Zuo, Huakun; Zhao, Yanfei; Sun, Yi; Xia, Zhengcai; He, Ke; Ma, Xucun; Xie, X. C.; Xue, Qi-Kun; Wang, Jian

    2014-07-01

    We report transport studies on the 5 nm thick Bi2Se3 topological insulator films which are grown via molecular beam epitaxy technique. The angle-resolved photoemission spectroscopy data show that the Fermi level of the system lies in the bulk conduction band above the Dirac point, suggesting important contribution of bulk states to the transport results. In particular, the crossover from weak antilocalization to weak localization in the bulk states is observed in the parallel magnetic field measurements up to 50 Tesla. The measured magneto-resistance exhibits interesting anisotropy with respect to the orientation of parallel magnetic field B// and the current I, signifying intrinsic spin-orbit coupling in the Bi2Se3 films. Our work directly shows the crossover of quantum interference effect in the bulk states from weak antilocalization to weak localization. It presents an important step toward a better understanding of the existing three-dimensional topological insulators and the potential applications of nano-scale topological insulator devices.

  18. Fano-Kondo and the Kondo box regimes crossover in a quantum dot coupled to a quantum box.

    PubMed

    Apel, Victor M; Orellana, Pedro A; Pacheco, Monica; Anda, Enrique V

    2013-12-18

    In this work, we study the Kondo effect of a quantum dot (QD) connected to leads and to a discrete set of one-particle states provided by a quantum box represented by a quantum ring (QR) pierced by a magnetic flux side attached to the QD. The interplay between the bulk Kondo effect and the so-called Kondo box regime is studied. In this system the QR energies can be continuously modified by the application of the magnetic field. The crossover between these two regimes is analyzed by changing the connection of the QD to the QR from the weak to the strong coupling regime. In the weak coupling regime, the differential conductance develops a sequence of Fano-Kondo anti-resonances due to destructive interference between the discrete quantum ring levels and the conducting Kondo channel provided by the leads. In the strong coupling regime the differential conductance has very sharp resonances when one of the Kondo discrete sub-levels characterizing the Kondo box is tuned by the applied potential. The conductance, the current fluctuations and the Fano coefficient result as being the relevant physical magnitudes to be analyzed to reveal the physical properties of these two Kondo regimes and the crossover region between them. The results were obtained by using the slave boson mean field theory (SBMFT).

  19. Crossover between Weak Antilocalization and Weak Localization of Bulk States in Ultrathin Bi2Se3 Films

    PubMed Central

    Wang, Huichao; Liu, Haiwen; Chang, Cui-Zu; Zuo, Huakun; Zhao, Yanfei; Sun, Yi; Xia, Zhengcai; He, Ke; Ma, Xucun; Xie, X. C.; Xue, Qi-Kun; Wang, Jian

    2014-01-01

    We report transport studies on the 5 nm thick Bi2Se3 topological insulator films which are grown via molecular beam epitaxy technique. The angle-resolved photoemission spectroscopy data show that the Fermi level of the system lies in the bulk conduction band above the Dirac point, suggesting important contribution of bulk states to the transport results. In particular, the crossover from weak antilocalization to weak localization in the bulk states is observed in the parallel magnetic field measurements up to 50 Tesla. The measured magneto-resistance exhibits interesting anisotropy with respect to the orientation of parallel magnetic field B// and the current I, signifying intrinsic spin-orbit coupling in the Bi2Se3 films. Our work directly shows the crossover of quantum interference effect in the bulk states from weak antilocalization to weak localization. It presents an important step toward a better understanding of the existing three-dimensional topological insulators and the potential applications of nano-scale topological insulator devices. PMID:25056600

  20. Demonstrations of Beats as Moving Interference Patterns.

    ERIC Educational Resources Information Center

    Stein, T. S.; Dishman, L. G.

    1982-01-01

    Describes a ripple tank demonstration that displays interference patterns responsible for producing beats and provides photographs of computer simulations of various beat interference patterns. Includes programs for the computer simulation and equations of constructive interference paths in beat interference patterns. (Author/SK)

  1. Low white blood cell count and cancer

    MedlinePlus

    Neutropenia and cancer; Absolute neutrophil count and cancer; ANC and cancer ... A person with cancer can get a low white blood cell count from the cancer or from treatment for the cancer. Cancer may ...

  2. Single Photon diffraction and interference

    NASA Astrophysics Data System (ADS)

    Hodge, John

    2015-04-01

    A previous paper based on the Scalar Theory of Everything studied photon diffraction and interference (IntellectualArchive, Vol.1, No. 3, P. 20, Toronto, Canada July 2012. http://intellectualarchive.com/?link=item&id=597). Several photons were required in the experiment at the same time. Interference experiments with one photon in the experiment at a time also showed interference patterns. The previous paper with the Bohm Interpretation, models of the screen and mask, and the Transaction Interpretation of Quantum Mechanics were combined. The reverse wave required by the Transaction Interpretation was provided by a reflected plenum wave rather than a reverse time wave. The speed of the plenum wave was assumed to be much faster than the speed of photons/light. Using the assumptions of Fraunhofer diffraction resulted in the same equation for the photon distribution on a screen as the intensity pattern of the Fraunhofer diffraction. (http://myplace.frontier.com/ ~ jchodge/)

  3. The spatial regulation of meiotic recombination hotspots: are all DSB hotspots crossover hotspots?

    PubMed

    Serrentino, Maria-Elisabetta; Borde, Valérie

    2012-07-15

    A key step for the success of meiosis is programmed homologous recombination, during which crossovers, or exchange of chromosome arms, take place. Crossovers increase genetic diversity but their main function is to ensure accurate chromosome segregation. Defects in crossover number and position produce aneuploidies that represent the main cause of miscarriages and chromosomal abnormalities such as Down's syndrome. Recombination is initiated by the formation of programmed double strand breaks (DSBs), which occur preferentially at places called DSB hotspots. Among all DSBs generated, only a small fraction is repaired by crossover, the other being repaired by other homologous recombination pathways. Crossover maps have been generated in a number of organisms, defining crossover hotspots. With the availability of genome-wide maps of DSBs as well as the ability to measure genetically the repair outcome at several hotspots, it is becoming more and more clear that not all DSB hotspots behave the same for crossover formation, suggesting that chromosomal features distinguish different types of hotspots.

  4. Control of Meiotic Crossovers: From Double-Strand Break Formation to Designation

    PubMed Central

    Gray, Stephen

    2017-01-01

    Meiosis, the mechanism of creating haploid gametes, is a complex cellular process observed across sexually reproducing organisms. Fundamental to meiosis is the process of homologous recombination, whereby DNA double-strand breaks are introduced into the genome and are subsequently repaired to generate either noncrossovers or crossovers. Although homologous recombination is essential for chromosome pairing during prophase I, the resulting crossovers are critical for maintaining homolog interactions and enabling accurate segregation at the first meiotic division. Thus, the placement, timing, and frequency of crossover formation must be exquisitely controlled. In this review, we discuss the proteins involved in crossover formation, the process of their formation and designation, and the rules governing crossovers, all within the context of the important landmarks of prophase I. We draw together crossover designation data across organisms, analyze their evolutionary divergence, and propose a universal model for crossover regulation. PMID:27648641

  5. Modeling and Simulation of Count Data

    PubMed Central

    Plan, E L

    2014-01-01

    Count data, or number of events per time interval, are discrete data arising from repeated time to event observations. Their mean count, or piecewise constant event rate, can be evaluated by discrete probability distributions from the Poisson model family. Clinical trial data characterization often involves population count analysis. This tutorial presents the basics and diagnostics of count modeling and simulation in the context of pharmacometrics. Consideration is given to overdispersion, underdispersion, autocorrelation, and inhomogeneity. PMID:25116273

  6. Crossover behavior in hydrogen sensing mechanism for palladium ultrathin films.

    SciTech Connect

    Darling, S. B.; Ramanathan, M.; Skudlarek, G.; Wang, H. H.; Illinois Math and Science Academy

    2010-01-01

    Palladium has been extensively studied as a material for hydrogen sensors because of the simplicity of its reversible resistance change when exposed to hydrogen gas. Various palladium films and nanostructures have been used, and different responses have been observed with these diverse morphologies. In some cases, such as with nanowires, the resistance will decrease, whereas in others, such as with thick films, the resistance will increase. Each of these mechanisms has been explored for several palladium structures, but the crossover between them has not been systematically investigated. Here we report on a study aimed at deciphering the nanostructure-property relationships of ultrathin palladium films used as hydrogen gas sensors. The crossover in these films is observed at a thickness of {approx} 5 nm. Ramifications for future sensor developments are discussed.

  7. Tuning the quantum critical crossover in quantum dots

    NASA Astrophysics Data System (ADS)

    Murthy, Ganpathy

    2005-03-01

    Quantum dots with large Thouless number g embody a regime where both disorder and interactions can be treated nonperturbatively using large-N techniques (with N=g) and quantum phase transitions can be studied. Here we focus on dots where the noninteracting Hamiltonian is drawn from a crossover ensemble between two symmetry classes, where the crossover parameter introduces a new, tunable energy scale independent of and much smaller than the Thouless energy. We show that the quantum critical regime, dominated by collective critical fluctuations, can be accessed at the new energy scale. The nonperturbative physics of this regime can only be described by the large-N approach, as we illustrate with two experimentally relevant examples. G. Murthy, PRB 70, 153304 (2004). G. Murthy, R. Shankar, D. Herman, and H. Mathur, PRB 69, 075321 (2004)

  8. Chiral relaxation time at the crossover of quantum chromodynamics

    NASA Astrophysics Data System (ADS)

    Ruggieri, M.; Peng, G. X.; Chernodub, M.

    2016-09-01

    We study microscopic processes responsible for chirality flips in the thermal bath of quantum chromodynamics at finite temperature and zero baryon chemical potential. We focus on the temperature range where the crossover from chirally broken phase to quark-gluon plasma takes place, namely, T ≃(150 ,200 ) MeV . The processes we consider are quark-quark scatterings mediated by collective excitations with the quantum number of pions and σ meson; hence we refer to these processes simply as one-pion (one-σ ) exchanges. We use a Nambu-Jona-Lasinio model to compute equilibrium properties of the thermal bath, as well as the relevant scattering kernel to be used in the collision integral to estimate the chiral relaxation time τ . We find τ ≃0.1 ÷1 fm /c around the chiral crossover.

  9. Isospin Dependent Pairing Interactions and BCS-BEC crossover

    SciTech Connect

    Sagawa, H.; Margueron, J.; Hagino, K.

    2008-11-11

    We propose new types of density dependent contact pairing interaction which reproduce the pairing gaps in symmetric and neutron matters obtained by a microscopic treatment based on the realistic nucleon-nucleon interaction. The BCS-BEC crossover of neutrons pairs in symmetric and asymmetric nuclear matters is studied by using these contact interactions. It is shown that the bare and screened pairing interactions lead to different features of the BCS-BEC crossover in symmetric nuclear matter. We perform Hartree-Fock-Bogoliubov (HFB) calculations for semi-magic Calcium, Nickel, Tin and Lead isotopes and N = 20, 28, 50 and 82 isotones using these density-dependent pairing interactions. Our calculations well account for the experimental data for the neutron number dependence of binding energy, two neutrons separation energy, and odd-even mass staggering of these isotopes. Especially the interaction IS+IV Bare without the medium polarization effect gives satisfactory results for all the isotopes.

  10. 3D Framework DNA Origami with Layered Crossovers.

    PubMed

    Hong, Fan; Jiang, Shuoxing; Wang, Tong; Liu, Yan; Yan, Hao

    2016-10-04

    Designer DNA architectures with nanoscale geometric controls provide a programmable molecular toolbox for engineering complex nanodevices. Scaffolded DNA origami has dramatically improved our ability to design and construct DNA nanostructures with finite size and spatial addressability. Here we report a novel design strategy to engineer multilayered wireframe DNA structures by introducing crossover pairs that connect neighboring layers of DNA double helices. These layered crossovers (LX) allow the scaffold or helper strands to travel through different layers and can control the relative orientation of DNA helices in neighboring layers. Using this design strategy, we successfully constructed four versions of two-layer parallelogram structures with well-defined interlayer angles, a three-layer structure with triangular cavities, and a 9- and 15-layer square lattices. This strategy provides a general route to engineer 3D framework DNA nanostructures with controlled cavities and opportunities to design host-guest networks analogs to those produced with metal organic frameworks.

  11. Cascading dynamics on random networks: crossover in phase transition.

    PubMed

    Liu, Run-Ran; Wang, Wen-Xu; Lai, Ying-Cheng; Wang, Bing-Hong

    2012-02-01

    In a complex network, random initial attacks or failures can trigger subsequent failures in a cascading manner, which is effectively a phase transition. Recent works have demonstrated that in networks with interdependent links so that the failure of one node causes the immediate failures of all nodes connected to it by such links, both first- and second-order phase transitions can arise. Moreover, there is a crossover between the two types of transitions at a critical system-parameter value. We demonstrate that these phenomena can occur in the more general setting where no interdependent links are present. A heuristic theory is derived to estimate the crossover and phase-transition points, and a remarkable agreement with numerics is obtained.

  12. Cascading dynamics on random networks: Crossover in phase transition

    NASA Astrophysics Data System (ADS)

    Liu, Run-Ran; Wang, Wen-Xu; Lai, Ying-Cheng; Wang, Bing-Hong

    2012-02-01

    In a complex network, random initial attacks or failures can trigger subsequent failures in a cascading manner, which is effectively a phase transition. Recent works have demonstrated that in networks with interdependent links so that the failure of one node causes the immediate failures of all nodes connected to it by such links, both first- and second-order phase transitions can arise. Moreover, there is a crossover between the two types of transitions at a critical system-parameter value. We demonstrate that these phenomena can occur in the more general setting where no interdependent links are present. A heuristic theory is derived to estimate the crossover and phase-transition points, and a remarkable agreement with numerics is obtained.

  13. Assestment of correlations and crossover scale in electroseismic time series

    NASA Astrophysics Data System (ADS)

    Guzman-Vargas, L.; Ramírez-Rojas, A.; Angulo-Brown, F.

    2009-04-01

    Evaluating complex fluctuations in electroseismic time series is an important task not only for earthquake prediction but also for understanding complex processes related to earthquake preparation. Previous studies have reported alterations, as the emergence of correlated dynamics in geoelectric potentials prior to an important earthquake (EQ). In this work, we apply the detrended fluctuation analysis and introduce a statistical procedure to characterize the presence of crossovers in scaling exponents, to analyze the fluctuations of geoelectric time series monitored in two sites located in Mexico. We find a complex behavior characterized by the presence of a crossover in the correlation exponents in the vicinity of a M=7.4 EQ occurred on Sept. 14, 1995. Finally, we apply the t-student test to evaluate the level of significance between short and large scaling exponents.

  14. Hot Neutron Stars with Hadron-Quark Crossover

    NASA Astrophysics Data System (ADS)

    Masuda, Kota; Hatsuda, Tetsuo; Takatsuka, Tatsuyuki

    2016-12-01

    The effects of the hadron-quark crossover on the bulk properties of cold and hot neutron stars (NSs) are studied. We suggested a new phenomenological equation of state (EOS), which interpolates the two phases at around 3 times the nuclear matter density (ρ0), and found that the cold NSs with the gravitational mass larger than 2M⊙ can be sustained. This is in sharp contrast to the case of the first-order hadron-quark transition where the quark matter inevitably leads to soft EOS. The interpolated EOS is also generalized to the supernova matter at finite temperature to describe the hot NSs at birth. The hadron-quark crossover is found to decrease the central temperature of the hot NSs under isentropic condition due to the color degrees of freedom.

  15. Thermodynamics of ultracold Bose gases at a dimensional crossover

    NASA Astrophysics Data System (ADS)

    Labouvie, Ralf; Vogler, Andreas; Guarrera, Vera; Ott, Herwig

    2013-05-01

    We have studied the thermodynamics of ultracold Bose gases in the crossover from a three-dimensional to a one-dimensional regime. In our experiment, we use a focused electron-beam to probe in situ atomic density distributions with high temporal and spatial resolution. Starting with a Bose-Einstein-Condensate in a single beam optical dipole trap we can create one-dimensional systems by loading the atoms in a two-dimensional blue-detuned optical lattice. With increasing strength of the lattices we go from a three-dimensional into a one-dimensional system. Furthermore we tune the interaction strengths of the one-dimensional quantum-gases from weak (quasi-condensate) to strong (Tonks-Girardeau). By measuring the density profiles and applying an inverse Abel-Transformation we extract the equation of states of these systems and characterize the crossover from the three-dimensional to the one-dimensional regime.

  16. Dynamical Crossover in Complex Networks near the Percolation Transition

    NASA Astrophysics Data System (ADS)

    Kawasaki, Fumiya; Yakubo, Kousuke

    2011-10-01

    The return probability P0(t) of random walkers is investigated numerically for several scale-free fractal networks. Our results show that P0(t) is proportional to t-ds/2 with the non-integer spectral dimension ds as in the case of non-scale free fractal networks. We also study how the diffusion process is affected by the structural crossover from a fractal to a small-world architecture in a network near the percolation transition. It is elucidated that the corresponding dynamical crossover is scaled only by the unique characteristic time tξ regardless of whether the network is scale free or not. In addition, the scaling relation ds= 2Df/dw is found to be valid even for scale-free fractal networks, where Df and dw are the fractal and the walk dimensions. These results suggest that qualitative properties of P0(t) are irrelevant to the scale-free nature of networks.

  17. Interference of probabilities in dynamics

    SciTech Connect

    Zak, Michail

    2014-08-15

    A new class of dynamical systems with a preset type of interference of probabilities is introduced. It is obtained from the extension of the Madelung equation by replacing the quantum potential with a specially selected feedback from the Liouville equation. It has been proved that these systems are different from both Newtonian and quantum systems, but they can be useful for modeling spontaneous collective novelty phenomena when emerging outputs are qualitatively different from the weighted sum of individual inputs. Formation of language and fast decision-making process as potential applications of the probability interference is discussed.

  18. Interference-based molecular transistors

    PubMed Central

    Li, Ying; Mol, Jan A.; Benjamin, Simon C.; Briggs, G. Andrew D.

    2016-01-01

    Molecular transistors have the potential for switching with lower gate voltages than conventional field-effect transistors. We have calculated the performance of a single-molecule device in which there is interference between electron transport through the highest occupied molecular orbital and the lowest unoccupied molecular orbital of a single molecule. Quantum interference results in a subthreshold slope that is independent of temperature. For realistic parameters the change in gate potential required for a change in source-drain current of two decades is 20 mV, which is a factor of six smaller than the theoretical limit for a metal-oxide-semiconductor field-effect transistor. PMID:27646692

  19. Hyperon puzzle, hadron-quark crossover and massive neutron stars

    NASA Astrophysics Data System (ADS)

    Masuda, Kota; Hatsuda, Tetsuo; Takatsuka, Tatsuyuki

    2016-03-01

    Bulk properties of cold and hot neutron stars are studied on the basis of the hadron-quark crossover picture where a smooth transition from the hadronic phase to the quark phase takes place at finite baryon density. By using a phenomenological equation of state (EOS) "CRover", which interpolates the two phases at around 3 times the nuclear matter density (ρ0, it is found that the cold NSs with the gravitational mass larger than 2M_{odot} can be sustained. This is in sharp contrast to the case of the first-order hadron-quark transition. The radii of the cold NSs with the CRover EOS are in the narrow range (12.5 ± 0.5) km which is insensitive to the NS masses. Due to the stiffening of the EOS induced by the hadron-quark crossover, the central density of the NSs is at most 4 ρ0 and the hyperon-mixing barely occurs inside the NS core. This constitutes a solution of the long-standing hyperon puzzle. The effect of color superconductivity (CSC) on the NS structures is also examined with the hadron-quark crossover. For the typical strength of the diquark attraction, a slight softening of the EOS due to two-flavor CSC (2SC) takes place and the maximum mass is reduced by about 0.2M_{odot}. The CRover EOS is generalized to the supernova matter at finite temperature to describe the hot NSs at birth. The hadron-quark crossover is found to decrease the central temperature of the hot NSs under isentropic condition. The gravitational energy release and the spin-up rate during the contraction from the hot NS to the cold NS are also estimated.

  20. Dimensional crossover in the torque in a layered superconductor

    NASA Astrophysics Data System (ADS)

    Klemm, R. A.

    1993-04-01

    The procedure of Bulaevski, Ledvij, and Kogan for evaluating the line energy of single, straight vortex in the Lawrence-Doniach model in the linearized phase-only approximation is modified to take accurate account of the vortex core cross-sections. Dimensional crossover effects are found to be pronounced, with oscillations in the regular dependence of the torque for theta approximately = pi/2 and T approximately = T* less than Tc.

  1. The case-crossover study design in pharmacoepidemiology.

    PubMed

    Delaney, Joseph A 'Chris'; Suissa, Samy

    2009-02-01

    In the study of the association of transient drug exposures with acute outcomes, the case-crossover design is an efficient alternative to the case-control approach. This design based exclusively on the case series uses within-subject comparisons of drug exposures over time to estimate the rate ratio of the outcome associated with the drug under study. This design inherently removes the biasing effects of unmeasured, time-invariant confounding factors from the estimated rate ratio, but is sensitive to several assumptions. We illustrated the case-crossover design and explored its sensitivity using data from 4028 cases of gastrointestinal bleeding from the General Practice Research Database in assessing the effects of the drug warfarin. We compared the use of different time window lengths to assess exposure and considered the use of a case-time-control design to account for exposure time trends. The case-crossover approach found no excess risk of bleeding with warfarin exposure [rate ratio 0.98; 95% confidence interval (CI): 0.74-1.28] using a 1-month time window. When we restricted the analysis to subjects with truly transient drug exposure, defined by 1 to 3 prescriptions in the previous year, the rate ratio was 2.59 (95% CI: 1.42-4.74). To consider the longer 1-year exposure time window, the case-time-control approach was used and resulted in a rate ratio of 1.72 (95% CI: 1.08-2.43). In conclusion, the case-crossover design is potentially a powerful approach to assess the risk of drugs. This design is, however, highly sensitive to assumptions about intermittency of drug use and the length of the exposure time window, as demonstrated with the example of bleeding associated with warfarin use.

  2. Surface and Size Effects in Spin-Crossover Nanocrystals

    NASA Astrophysics Data System (ADS)

    Gudyma, Iurii; Ivashko, Victor; Bobák, Andrej

    2017-02-01

    We perform Monte Carlo simulations to analyze the surface and size effects in spin-crossover nanocrystals using an Ising-like model including surface and core intermolecular interactions. The consequences of downsizing effect on the transition temperature and the width of hysteresis as finger of the system cooperativity are discussed. The critical temperature is calculated using the real-space renormalization method. The obtained results are in agreement with the experimental data.

  3. Persistent User Bias in Case-Crossover Studies in Pharmacoepidemiology.

    PubMed

    Hallas, Jesper; Pottegård, Anton; Wang, Shirley; Schneeweiss, Sebastian; Gagne, Joshua J

    2016-10-25

    Studying the effect of chronic medication exposure by means of a case-crossover design may result in an upward-biased odds ratio. In this study, our aim was to assess the occurrence of this bias and to evaluate whether it is remedied by including a control group (the case-time-control design). Using Danish data resources from 1995-2012, we conducted case-crossover and case-time-control analyses for 3 medications (statins, insulin, and thyroxine) in relation to 3 outcomes (retinal detachment, wrist fracture, and ischemic stroke), all with assumed null associations. Controls were matched on age, sex, and index date, and exposure over the preceding 12 months was ascertained. For retinal detachment, the case-crossover odds ratio was 1.60 (95% confidence interval (CI): 1.42, 1.80) for statins, 1.40 (95% CI: 1.02, 1.92) for thyroxine, and 1.53 (95% CI: 1.04, 2.24) for insulin. Estimates for the retinal detachment controls were similar, leading to near-null case-time-control estimates for all 3 medication classes. For wrist fracture and stroke, the odds ratios were higher for cases than for controls, and case-time-control odds ratios were consistently above unity, thus implying significant residual bias. In case-crossover studies of medications, contamination by persistent users confers a moderate bias upward, which is partly remedied by using a control group. The optimal strategy for dealing with this problem is currently unknown.

  4. Flow equations for the BCS-BEC crossover

    SciTech Connect

    Diehl, S.; Gies, H.; Pawlowski, J. M.; Wetterich, C.

    2007-08-15

    The functional renormalization group is used for the BCS-BEC crossover in gases of ultracold fermionic atoms. In a simple truncation, we see how universality and an effective theory with composite bosonic diatom states emerge. We obtain a unified picture of the whole phase diagram. The flow reflects different effective physics at different scales. In the BEC limit as well as near the critical temperature, it describes an interacting bosonic theory.

  5. SPERM COUNT DISTRIBUTIONS IN FERTILE MEN

    EPA Science Inventory

    Sperm concentration and count are often used as indicators of environmental impacts on male reproductive health. Existing clinical databases may be biased towards subfertile men with low sperm counts and less is known about expected sperm count distributions in cohorts of fertil...

  6. Monte Carlo Simulation of Counting Experiments.

    ERIC Educational Resources Information Center

    Ogden, Philip M.

    A computer program to perform a Monte Carlo simulation of counting experiments was written. The program was based on a mathematical derivation which started with counts in a time interval. The time interval was subdivided to form a binomial distribution with no two counts in the same subinterval. Then the number of subintervals was extended to…

  7. Count-doubling time safety circuit

    DOEpatents

    Rusch, Gordon K.; Keefe, Donald J.; McDowell, William P.

    1981-01-01

    There is provided a nuclear reactor count-factor-increase time monitoring circuit which includes a pulse-type neutron detector, and means for counting the number of detected pulses during specific time periods. Counts are compared and the comparison is utilized to develop a reactor scram signal, if necessary.

  8. DC KIDS COUNT e-Databook Indicators

    ERIC Educational Resources Information Center

    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…

  9. C_60/Ferromagnet Composites: Observation of a Temperature-Dependent Crossover from Negative to Positive Magnetoresistance

    NASA Astrophysics Data System (ADS)

    Hudspeth, Q. M.; Arnason, S. B.; Hebard, A. F.

    2001-03-01

    In this work we report on the fabrication and characterization of composite thin films (M_xC_60) of C_60 with ferromagnetic metals (M). Magnetoresistance (MR) measurements will be presented for Ni_xC_60 samples with x in the range 20 - 90. A change in MR from negative (characteristic of pure Ni) at high temperatures to positive at low temperatures is observed as the sample temperature is decreased from 300 to 2 K. This crossover from negative to positive MR is similar to that seen below 1 K in phosphorous-doped silicon[1], and more recently at higher temperatures in Fe_1-yCo_ySi[2] and is attributed to quantum interference effects in the presence of Coulomb interactions with spin splitting. This interpretation can be tested for the M_xC_60 composites by comparing the MR of M_xC_60 (M= Fe, Co, Ni) with Gd_xC_60. In the Gd composite we would expect the positive MR to be absent since magnetism in Gd arises from local moments and the carriers are no longer responsible for both magnetism and conduction as they are in Fe_1-yCo_ySi. [1] T. F. Rosenbaum et al., Phys. Rev. Lett. 47, 1758 (1981). [2] N. Manyala, et al., Nature 404, 581 (2000).

  10. Genome-Wide Crossover Distribution in Arabidopsis thaliana Meiosis Reveals Sex-Specific Patterns along Chromosomes

    PubMed Central

    Drouaud, Jan; Pereira, Lucie; Martin, Olivier C.; Mézard, Christine

    2011-01-01

    In most species, crossovers (COs) are essential for the accurate segregation of homologous chromosomes at the first meiotic division. Their number and location are tightly regulated. Here, we report a detailed, genome-wide characterization of the rate and localization of COs in Arabidopsis thaliana, in male and female meiosis. We observed dramatic differences between male and female meiosis which included: (i) genetic map length; 575 cM versus 332 cM respectively; (ii) CO distribution patterns: male CO rates were very high at both ends of each chromosome, whereas female CO rates were very low; (iii) correlations between CO rates and various chromosome features: female CO rates correlated strongly and negatively with GC content and gene density but positively with transposable elements (TEs) density, whereas male CO rates correlated positively with the CpG ratio. However, except for CpG, the correlations could be explained by the unequal repartition of these sequences along the Arabidopsis chromosome. For both male and female meiosis, the number of COs per chromosome correlates with chromosome size expressed either in base pairs or as synaptonemal complex length. Finally, we show that interference modulates the CO distribution both in male and female meiosis. PMID:22072983

  11. Pressure and Temperature Spin Crossover Sensors with Optical Detection

    PubMed Central

    Linares, Jorge; Codjovi, Epiphane; Garcia, Yann

    2012-01-01

    Iron(II) spin crossover molecular materials are made of coordination centres switchable between two states by temperature, pressure or a visible light irradiation. The relevant macroscopic parameter which monitors the magnetic state of a given solid is the high-spin (HS) fraction denoted nHS, i.e., the relative population of HS molecules. Each spin crossover material is distinguished by a transition temperature T1/2 where 50% of active molecules have switched to the low-spin (LS) state. In strongly interacting systems, the thermal spin switching occurs abruptly at T1/2. Applying pressure induces a shift from HS to LS states, which is the direct consequence of the lower volume for the LS molecule. Each material has thus a well defined pressure value P1/2. In both cases the spin state change is easily detectable by optical means thanks to a thermo/piezochromic effect that is often encountered in these materials. In this contribution, we discuss potential use of spin crossover molecular materials as temperature and pressure sensors with optical detection. The ones presenting smooth transitions behaviour, which have not been seriously considered for any application, are spotlighted as potential sensors which should stimulate a large interest on this well investigated class of materials. PMID:22666041

  12. Crossover among structural motifs in Pd-Au nanoalloys.

    PubMed

    Zhu, Beien; Guesmi, Hazar; Creuze, Jérôme; Legrand, Bernard; Mottet, Christine

    2015-11-14

    The crossovers among the most abundant structural motifs (icosahedra, decahedra and truncated octahedra) of Pd-Au nanoalloys have been determined theoretically in a size range between 2 and 7 nm and for three compositions equivalent to Pd3Au, PdAu and PdAu3. The chemical ordering and segregation optimisation are performed via Monte Carlo simulations using semi-empirical tight-binding potentials fitted to ab initio calculations. The chemical configurations are then quenched via molecular dynamic simulations in order to compare their energy and characterize the equilibrium structures as a function of the cluster size. For the smaller sizes (of around 300 atoms and fewer) the structures are also optimized at the electronic level within ab initio calculations in order to validate the semi-empirical potential. The predictions of the crossover sizes for the nanoalloys cannot be simply extrapolated from the crossover of the pure nanoparticles but imply stress release phenomena related to the size misfit between the two metals. Indeed, alloying extends the range of stability of the icosahedron beyond that of the pure systems and the energy differences between decahedra and truncated octahedra become asymptotic, around the sizes of 5-6 nm. Nevertheless, such equilibrium results should be modulated regarding kinetic considerations or possible gas adsorption under experimental conditions.

  13. Automatic identification of vessel crossovers in retinal images

    NASA Astrophysics Data System (ADS)

    Sánchez, L.; Barreira, N.; Penedo, M. G.; Cancela, B.

    2015-02-01

    Crossovers and bifurcations are interest points of the retinal vascular tree useful to diagnose diseases. Specifically, detecting these interest points and identifying which of them are crossings will give us the opportunity to search for arteriovenous nicking, this is, an alteration of the vessel tree where an artery is crossed by a vein and the former compresses the later. These formations are a clear indicative of hypertension, among other medical problems. There are several studies that have attempted to define an accurate and reliable method to detect and classify these relevant points. In this article, we propose a new method to identify crossovers. Our approach is based on segmenting the vascular tree and analyzing the surrounding area of each interest point. The minimal path between vessel points in this area is computed in order to identify the connected vessel segments and, as a result, to distinguish between bifurcations and crossovers. Our method was tested using retinographies from public databases DRIVE and VICAVR, obtaining an accuracy of 90%.

  14. Spin crossover in ferropericlase and some consequences for mantle velocities

    NASA Astrophysics Data System (ADS)

    Wentzcovitch, R. M.

    2015-12-01

    The spin crossover in ferropericlase ((Mg,Fe)O) introduces anomalies in its thermodynamics and thermoelastic properties [1] with impactful consequences on lower mantle velocities. These anomalies fundamentally change the interpretation of the origin of lateral heterogeneities in the mid lower mantle. In particular, SCF reduces the sensitivity of longitudinal velocity (VP) to lateral temperature variations around 1700 km [2]. It also dramatically impacts the manifestation of two important types of compositional heterogeneities, i.e., change in iron concentration in Fp or in molar fraction of Fp in the aggregate. It enhances the sensitivity of Vϕ and VP to these compositional variations by several-fold. In addition, it affects the mantle adiabatic geotherm, altering the radial velocity profile. Here I will review these effects and relate them to some potential features observed in seismic tomography models. [1] Wu, Z.Q., Justo, J. F., & Wentzcovitch, R.M. (2013). Elastic anomalies in a spin-crossover system: ferropericlase at lower mantle conditions, Phys. Rev. Lett. 110, 228501 (2013). [2] Wu, Z.Q., & Wentzcovitch, R.M. (2014). Spin crossover in ferropericlase and velocity heterogeneities in the lower mantle. Proc. Natl. Acad. Sci. U. S. A. 111: 10468-10472.

  15. Case-crossover design and its implementation in R.

    PubMed

    Zhang, Zhongheng

    2016-09-01

    Case-crossover design is a variation of case-control design that it employs persons' history periods as controls. Case-crossover design can be viewed as the hybrid of case-control study and crossover design. Characteristic confounding that is constant within one person can be well controlled with this method. The relative risk and odds ratio, as well as their 95% confidence intervals (CIs), can be estimated using Cochran-Mantel-Haenszel method. R codes for the calculation are provided in the main text. Readers may adapt these codes to their own task. Conditional logistic regression model is another way to estimate odds ratio of the exposure. Furthermore, it allows for incorporation of other time-varying covariates that are not constant within subjects. The model fitting per se is not technically difficult because there is well developed statistical package. However, it is challenging to convert original dataset obtained from case report form to that suitable to be passed to clogit() function. R code for this task is provided and explained in the text.

  16. Residuals and outliers in replicate design crossover studies.

    PubMed

    Schall, Robert; Endrenyi, Laszlo; Ring, Arne

    2010-07-01

    Outliers in bioequivalence trials may arise through various mechanisms, requiring different interpretation and handling of such data points. For example, regulatory authorities might permit exclusion from analysis of outliers caused by product or process failure, while exclusion of outliers caused by subject-by-treatment interaction generally is not acceptable. In standard 2 x 2 crossover studies it is not possible to distinguish between relevant types of outliers based on statistical criteria alone. However, in replicate design (2-treatment, 4-period) crossover studies three types of outliers can be distinguished: (i) Subject outliers are usually unproblematic, at least regarding the analysis of bioequivalence, and may require no further action; (ii) Subject-by-formulation outliers may affect the outcome of the bioequivalence test but generally cannot simply be removed from analysis; and (iii) Removal of single-data-point outliers from analysis may be justified in certain cases. As a very simple but effective diagnostic tool for the identification and classification of outliers in replicate design crossover studies we propose to calculate and plot three types of residual corresponding to the three different types of outliers that can be distinguished. The residuals are obtained from four mutually orthogonal linear contrasts of the four data points associated with each subject. If preferred, outlier tests can be applied to the resulting sets of residuals after suitable standardization.

  17. Master crossover functions for one-component fluids.

    PubMed

    Garrabos, Yves; Lecoutre, Carole; Palencia, Fabien; Le Neindre, Bernard; Erkey, Can

    2008-02-01

    By introducing three well-defined dimensionless numbers, we establish the link between the scale dilatation method able to estimate master (i.e., unique) singular behaviors of the one-component fluid subclass and the universal crossover functions recently estimated [Garrabos and Bervillier, Phys. Rev. E 74, 021113 (2006)] from the bounded results of the massive renormalization scheme applied to the Phi(d)(4)(n) model of scalar order parameter (n=1) and three dimensions (d=3), representative of the Ising-like universality class. The master (i.e., rescaled) crossover functions are then able to fit the singular behaviors of any one-component fluid without adjustable parameter, using only one critical energy scale factor, one critical length scale factor, and two dimensionless asymptotic scale factors, which characterize the fluid critical interaction cell at its liquid-gas critical point. An additional adjustable parameter accounts for quantum effects in light fluids at the critical temperature. The effective extension of the thermal field range along the critical isochore where the master crossover functions seems to be valid corresponds to a correlation length greater than three times the effective range of the microscopic short-range molecular interaction.

  18. Digital coincidence counting - initial results

    NASA Astrophysics Data System (ADS)

    Butcher, K. S. A.; Watt, G. C.; Alexiev, D.; van der Gaast, H.; Davies, J.; Mo, Li; Wyllie, H. A.; Keightley, J. D.; Smith, D.; Woods, M. J.

    2000-08-01

    Digital Coincidence Counting (DCC) is a new technique in radiation metrology, based on the older method of analogue coincidence counting. It has been developed by the Australian Nuclear Science and Technology Organisation (ANSTO), in collaboration with the National Physical Laboratory (NPL) of the United Kingdom, 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 an 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. In this letter we describe some recent results obtained with the new acquistion hardware being tested at ANSTO. The system is fully operational and is now in routine use. Results for 60Co and 22Na radiation activity calibrations are presented, initial results with 153Sm are also briefly mentioned.

  19. Analysis of radioactive strontium-90 in food by Čerenkov liquid scintillation counting.

    PubMed

    Pan, Jingjing; Emanuele, Kathryn; Maher, Eileen; Lin, Zhichao; Healey, Stephanie; Regan, Patrick

    2017-01-27

    A simple liquid scintillation counting method using DGA/TRU resins for removal of matrix/radiometric interferences, Čerenkov counting for measuring (90)Y, and EDXRF for quantifying Y recovery was validated for analyzing (90)Sr in various foods. Analysis of samples containing energetic β emitters required using TRU resin to avoid false detection and positive bias. Additional 34% increase in Y recovery was obtained by stirring the resin while eluting Y with H2C2O4. The method showed acceptable accuracy (±10%), precision (10%), and detectability (~0.09Bqkg(-1)).

  20. A Next Generation Digital Counting System For Low-Level Tritium Studies (Project Report)

    SciTech Connect

    Bowman, P.

    2016-10-03

    Since the early seventies, SRNL has pioneered low-level tritium analysis using various nuclear counting technologies and techniques. Since 1999, SRNL has successfully performed routine low-level tritium analyses with counting systems based on digital signal processor (DSP) modules developed in the late 1990s. Each of these counting systems are complex, unique to SRNL, and fully dedicated to performing routine tritium analyses of low-level environmental samples. It is time to modernize these systems due to a variety of issues including (1) age, (2) lack of direct replacement electronics modules and (3) advances in digital signal processing and computer technology. There has been considerable development in many areas associated with the enterprise of performing low-level tritium analyses. The objective of this LDRD project was to design, build, and demonstrate a Next Generation Tritium Counting System (NGTCS), while not disrupting the routine low-level tritium analyses underway in the facility on the legacy counting systems. The work involved (1) developing a test bed for building and testing new counting system hardware that does not interfere with our routine analyses, (2) testing a new counting system based on a modern state of the art DSP module, and (3) evolving the low-level tritium counter design to reflect the state of the science.

  1. Fano Interference in Classical Oscillators

    ERIC Educational Resources Information Center

    Satpathy, S.; Roy, A.; Mohapatra, A.

    2012-01-01

    We seek to illustrate Fano interference in a classical coupled oscillator by using classical analogues of the atom-laser interaction. We present an analogy between the dressed state picture of coherent atom-laser interaction and a classical coupled oscillator. The Autler-Townes splitting due to the atom-laser interaction is analogous to the…

  2. Suprasegmental Aspects of Reading Interference.

    ERIC Educational Resources Information Center

    Westbrook, Colston R.

    Information is presented in this paper regarding suprasegmental features of Black English thay may cause reading interference for some Black children. Much of the research concerning reading problems of many Afro-American students stresses the segmental differences of the phonology, the morphology, the syntax, and lexical selection between two…

  3. "Quantum Interference with Slits" Revisited

    ERIC Educational Resources Information Center

    Rothman, Tony; Boughn, Stephen

    2011-01-01

    Marcella has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his…

  4. Kids Count in Delaware, Families Count in Delaware: Fact Book, 2003.

    ERIC Educational Resources Information Center

    Delaware Univ., Newark. Kids Count in Delaware.

    This Kids Count Fact Book is combined with the Families Count Fact Book to provide information on statewide trends affecting children and families in Delaware. The Kids Count and Families Count indicators have been combined into four new categories: health and health behaviors, educational involvement and achievement, family environment and…

  5. Measuring 36Ar without H35Cl interference

    NASA Astrophysics Data System (ADS)

    Saxton, John

    2015-04-01

    Noble gas measurements are usually made in static mode, when the mass spectrometer sensitivity is inversely proportional to volume: this makes the building of very large instruments to obtain high mass resolution impracticable. A particularly challenging interference has hitherto been H35Cl, which differs in mass from 36Ar by 1 part in 3937. We have developed a method which makes improved use of the available MRP to remove interferences, and used it to obtain HCl-free 36Ar measurements on a multicollector instrument with MRP of only ~6000 (MRP= mass resolving power = m/dm 5-95% on side of peak). By arranging that the target mass position on a minor isotope (e.g. 36Ar), from which the interference must be removed, coincides with the ~50% point on the side of a major isotope (e.g. 40Ar), it is possible both to set the mass accurately and to verify the mass position and stability during measurements. The peak top of 40Ar is measured in a separate mass step. Two small corrections are necessary. One compensates for the residual HCl tail at the 36Ar position. The other arises because the peak is not totally flat in the region of interest: 40Ar and 36Ar+HCl are measured on the peak top, whilst 36Ar is measured at the extreme edge, with slightly lower efficiency. The required correction parameters can be obtained from a series of air calibrations with different target/interference ratios. With samples containing 4x10-15to 3x10-14moles of 40Ar, 36Ar/40Ar was measured, without HCl interference, to a 1σ precision of 0.5%, only slightly worse than counting statistics. This is potentially useful for 40Ar/39Ar dating, where 36Ar is used to correct for trapped air, and may be particularly significant for smaller or younger samples.

  6. Fine-Scale Crossover Rate Variation on the Caenorhabditis elegans X Chromosome

    PubMed Central

    Bernstein, Max R.; Rockman, Matthew V.

    2016-01-01

    Meiotic recombination creates genotypic diversity within species. Recombination rates vary substantially across taxa, and the distribution of crossovers can differ significantly among populations and between sexes. Crossover locations within species have been found to vary by chromosome and by position within chromosomes, where most crossover events occur in small regions known as recombination hotspots. However, several species appear to lack hotspots despite significant crossover heterogeneity. The nematode Caenorhabditis elegans was previously found to have the least fine-scale variation in crossover distribution among organisms studied to date. It is unclear whether this pattern extends to the X chromosome given its unique compaction through the pachytene stage of meiotic prophase in hermaphrodites. We generated 798 recombinant nested near-isogenic lines (NILs) with crossovers in a 1.41 Mb region on the left arm of the X chromosome to determine if its recombination landscape is similar to that of the autosomes. We find that the fine-scale variation in crossover rate is lower than that of other model species, and is inconsistent with hotspots. The relationship of genomic features to crossover rate is dependent on scale, with GC content, histone modifications, and nucleosome occupancy being negatively associated with crossovers. We also find that the abundances of 4- to 6-bp DNA motifs significantly explain crossover density. These results are consistent with recombination occurring at unevenly distributed sites of open chromatin. PMID:27172189

  7. Photon counting compressive depth mapping.

    PubMed

    Howland, Gregory A; Lum, Daniel J; Ware, Matthew R; Howell, John C

    2013-10-07

    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 × 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 × 32 pixel real-time video for three-dimensional object tracking at 14 frames-per-second.

  8. Counting solutions from finite samplings

    NASA Astrophysics Data System (ADS)

    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.

  9. Counting paths with Schur transitions

    NASA Astrophysics Data System (ADS)

    Díaz, Pablo; Kemp, Garreth; Véliz-Osorio, Alvaro

    2016-10-01

    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.

  10. Yoctocalorimetry: phonon counting in nanostructures

    NASA Astrophysics Data System (ADS)

    Roukes, M. L.

    1999-03-01

    It appears feasible with nanostructures to perform calorimetry at the level of individual thermal phonons. Here I outline an approach employing monocrystalline mesoscopic insulators, which can now be patterned from semiconductor heterostructures into complex geometries with full, three-dimensional relief. Successive application of these techniques also enables definition of integrated nanoscale thermal transducers; coupling these to a dc SQUID readout yields the requisite energy sensitivity and temporal resolution with minimal back action. The prospect of phonon counting opens intriguing experimental possibilities with analogies in quantum optics. These include fluctuation-based phonon spectroscopy, phonon shot noise in the energy relaxation of nanoscale systems, and quantum statistical phenomena such as phonon bunching and anticorrelated electron-phonon exchange.

  11. EASI - EQUILIBRIUM AIR SHOCK INTERFERENCE

    NASA Technical Reports Server (NTRS)

    Glass, C. E.

    1994-01-01

    New research on hypersonic vehicles, such as the National Aero-Space Plane (NASP), has raised concerns about the effects of shock-wave interference on various structural components of the craft. State-of-the-art aerothermal analysis software is inadequate to predict local flow and heat flux in areas of extremely high heat transfer, such as the surface impingement of an Edney-type supersonic jet. EASI revives and updates older computational methods for calculating inviscid flow field and maximum heating from shock wave interference. The program expands these methods to solve problems involving the six shock-wave interference patterns on a two-dimensional cylindrical leading edge with an equilibrium chemically reacting gas mixture (representing, for example, the scramjet cowl of the NASP). The inclusion of gas chemistry allows for a more accurate prediction of the maximum pressure and heating loads by accounting for the effects of high temperature on the air mixture. Caloric imperfections and specie dissociation of high-temperature air cause shock-wave angles, flow deflection angles, and thermodynamic properties to differ from those calculated by a calorically perfect gas model. EASI contains pressure- and temperature-dependent thermodynamic and transport properties to determine heating rates, and uses either a calorically perfect air model or an 11-specie, 7-reaction reacting air model at equilibrium with temperatures up to 15,000 K for the inviscid flowfield calculations. EASI solves the flow field and the associated maximum surface pressure and heat flux for the six common types of shock wave interference. Depending on the type of interference, the program solves for shock-wave/boundary-layer interaction, expansion-fan/boundary-layer interaction, attaching shear layer or supersonic jet impingement. Heat flux predictions require a knowledge (from experimental data or relevant calculations) of a pertinent length scale of the interaction. Output files contain flow

  12. Avian leucocyte counting using the hemocytometer

    USGS Publications Warehouse

    Dein, F.J.; Wilson, A.; Fischer, D.; Langenberg, P.

    1994-01-01

    Automated methods for counting leucocytes in avian blood are not available because of the presence of nucleated erythrocytes and thrombocytes. Therefore, total white blood cell counts are performed by hand using a hemocytometer. The Natt and Herrick and the Unopette methods are the most common stain and diluent preparations for this procedure. Replicate hemocytometer counts using these two methods were performed on blood from four birds of different species. Cells present in each square of the hemocytometer were counted. Counting cells in the corner, side, or center hemocytometer squares produced statistically equivalent results; counting four squares per chamber provided a result similar to that obtained by counting nine squares; and the Unopette method was more precise for hemocytometer counting than was the Natt and Herrick method. The Unopette method is easier to learn and perform but is an indirect process, utilizing the differential count from a stained smear. The Natt and Herrick method is a direct total count, but cell identification is more difficult.

  13. REM sleep rescues learning from interference.

    PubMed

    McDevitt, Elizabeth A; Duggan, Katherine A; Mednick, Sara C

    2015-07-01

    Classical human memory studies investigating the acquisition of temporally-linked events have found that the memories for two events will interfere with each other and cause forgetting (i.e., interference; Wixted, 2004). Importantly, sleep helps consolidate memories and protect them from subsequent interference (Ellenbogen, Hulbert, Stickgold, Dinges, & Thompson-Schill, 2006). We asked whether sleep can also repair memories that have already been damaged by interference. Using a perceptual learning paradigm, we induced interference either before or after a consolidation period. We varied brain states during consolidation by comparing active wake, quiet wake, and naps with either non-rapid eye movement sleep (NREM), or both NREM and REM sleep. When interference occurred after consolidation, sleep and wake both produced learning. However, interference prior to consolidation impaired memory, with retroactive interference showing more disruption than proactive interference. Sleep rescued learning damaged by interference. Critically, only naps that contained REM sleep were able to rescue learning that was highly disrupted by retroactive interference. Furthermore, the magnitude of rescued learning was correlated with the amount of REM sleep. We demonstrate the first evidence of a process by which the brain can rescue and consolidate memories damaged by interference, and that this process requires REM sleep. We explain these results within a theoretical model that considers how interference during encoding interacts with consolidation processes to predict which memories are retained or lost.

  14. REM sleep rescues learning from interference

    PubMed Central

    McDevitt, Elizabeth A.; Duggan, Katherine A.; Mednick, Sara C.

    2015-01-01

    Classical human memory studies investigating the acquisition of temporally-linked events have found that the memories for two events will interfere with each other and cause forgetting (i.e., interference; Wixted, 2004). Importantly, sleep helps consolidate memories and protect them from subsequent interference (Ellenbogen, Hulbert, Stickgold, Dinges, & Thompson-Schill, 2006). We asked whether sleep can also repair memories that have already been damaged by interference. Using a perceptual learning paradigm, we induced interference either before or after a consolidation period. We varied brain states during consolidation by comparing active wake, quiet wake, and naps with either non-rapid eye movement sleep (NREM), or both NREM and REM sleep. When interference occurred after consolidation, sleep and wake both produced learning. However, interference prior to consolidation impaired memory, with retroactive interference showing more disruption than proactive interference. Sleep rescued learning damaged by interference. Critically, only naps that contained REM sleep were able to rescue learning that was highly disrupted by retroactive interference. Furthermore, the magnitude of rescued learning was correlated with the amount of REM sleep. We demonstrate the first evidence of a process by which the brain can rescue and consolidate memories damaged by interference, and that this process requires REM sleep. We explain these results within a theoretical model that considers how interference during encoding interacts with consolidation processes to predict which memories are retained or lost. PMID:25498222

  15. Crossover of marital dissatisfaction during military downsizing among Russian army officers and their spouses.

    PubMed

    Westman, Mina; Vinokur, Amiram D; Hamilton, V Lee; Roziner, Ilan

    2004-10-01

    This study examined mechanisms of strain crossover within couples and the moderating role of gender. Data were collected at a time of military downsizing from a sample of 1,250 Russian army officers and their spouses. The authors tested a model that incorporated 3 mechanisms for the crossover of marital dissatisfaction among dual-earner couples. The model provided support for 2 suggested crossover mechanisms: direct reactions of crossover and indirect mediated effects through social undermining. Strong evidence was also provided for gender asymmetry in the crossover process. Marital dissatisfaction crossed over from husbands to wives but not vice versa, and social undermining behavior played a role in the process of crossover of marital dissatisfaction for husbands but not for wives.

  16. Silicon superconducting quantum interference device

    SciTech Connect

    Duvauchelle, J. E.; Francheteau, A.; Marcenat, C.; Lefloch, F.; Chiodi, F.; Débarre, D.; Hasselbach, K.; Kirtley, J. R.

    2015-08-17

    We have studied a Superconducting Quantum Interference Device (SQUID) made from a single layer thin film of superconducting silicon. The superconducting layer is obtained by heavily doping a silicon wafer with boron atoms using the gas immersion laser doping technique. The SQUID is composed of two nano-bridges (Dayem bridges) in a loop and shows magnetic flux modulation at low temperature and low magnetic field. The overall behavior shows very good agreement with numerical simulations based on the Ginzburg-Landau equations.

  17. Interference techniques in fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Dogan, Mehmet

    We developed a set of interference-based optical microscopy techniques to study biological structures through nanometer-scale axial localization of fluorescent biomarkers. Spectral self-interference fluorescence microscopy (SSFM) utilizes interference of direct and reflected waves emitted from fluorescent molecules in the vicinity of planar reflectors to reveal the axial position of the molecules. A comprehensive calculation algorithm based on Green's function formalism is presented to verify the validity of approximations used in a far-field approach that describes the emission of fluorescent markers near interfaces. Using the validated model, theoretical limits of axial localization were determined with emphasis given to numerical aperture (NA) dependence of localization uncertainty. SSFM was experimentally demonstrated in conformational analysis of nucleoproteins. In particular, interaction between surface-tethered 75-mer double strand DNA and integration host factor (IHF) protein was probed on Si-SiO2 substrates by determining the axial position of fluorescent labels attached to the free ends of DNA molecules. Despite its sub-nanometer precision axial localization capability, SSFM lacks high lateral resolution due to the low-NA requirement for planar reflectors. We developed a second technique, 4Pi-SSFM, which improves the lateral resolution of a conventional SSFM system by an order of magnitude while achieving nanometer-scale axial localization precision. Using two opposing high-NA objectives, fluorescence signal is interferometrically collected and spectral interference pattern is recorded. Axial position of emitters is found from analysis of the spectra. The 4Pi-SSFM technique was experimentally demonstrated by determining the surface profiles of fabricated glass surfaces and outer membranes of Shigella, a type of Gram-negative bacteria. A further discussion is presented to localize surface O antigen, which is an important oligosaccharide structure in the

  18. Structural insights into RNA interference.

    PubMed

    Sashital, Dipali G; Doudna, Jennifer A

    2010-02-01

    Virtually all animals and plants utilize small RNA molecules to control protein expression during different developmental stages and in response to viral infection. Structural and mechanistic studies have begun to illuminate three fundamental aspects of these pathways: small RNA biogenesis, formation of RNA-induced silencing complexes (RISCs), and targeting of complementary mRNAs. Here we review exciting recent progress in understanding how regulatory RNAs are produced and how they trigger specific destruction of mRNAs during RNA interference (RNAi).

  19. Extensive Interallelic Polymorphisms Drive Meiotic Recombination into a Crossover Pathway

    PubMed Central

    Dooner, Hugo K.

    2002-01-01

    Recombinants isolated from most meiotic intragenic recombination experiments in maize, but not in yeast, are borne principally on crossover chromosomes. This excess of crossovers is not explained readily by the canonical double-strand break repair model of recombination, proposed to account for a large body of yeast data, which predicts that crossovers (COs) and noncrossovers (NCOs) should be recovered equally. An attempt has been made here to identify general rules governing the recovery of the CO and NCO classes of intragenic recombinants in maize. Recombination was analyzed in bz heterozygotes between a variety of mutations derived from the same or different progenitor alleles. The mutations include point mutations, transposon insertions, and transposon excision footprints. Consequently, the differences between the bz heteroalleles ranged from just two nucleotides to many nucleotides, indels, and insertions. In this article, allelic pairs differing at only two positions are referred to as dimorphic to distinguish them from polymorphic pairs, which differ at multiple positions. The present study has revealed the following effects at these bz heteroalleles: (1) recombination between polymorphic heteroalleles produces mostly CO chromosomes; (2) recombination between dimorphic heteroalleles produces both CO and NCO chromosomes, in ratios apparently dependent on the nature of the heteroalleles; and (3) in dimorphic heterozygotes, the two NCO classes are recovered in approximately equal numbers when the two mutations are point mutations but not when one or both mutations are insertions. These observations are discussed in light of a recent version of the double-strand break repair model of recombination that postulates separate pathways for the formation of CO and NCO products. PMID:12034905

  20. Single water entropy: hydrophobic crossover and application to drug binding.

    PubMed

    Sasikala, Wilbee D; Mukherjee, Arnab

    2014-09-11

    Entropy of water plays an important role in both chemical and biological processes e.g. hydrophobic effect, molecular recognition etc. Here we use a new approach to calculate translational and rotational entropy of the individual water molecules around different hydrophobic and charged solutes. We show that for small hydrophobic solutes, the translational and rotational entropies of each water molecule increase as a function of its distance from the solute reaching finally to a constant bulk value. As the size of the solute increases (0.746 nm), the behavior of the translational entropy is opposite; water molecules closest to the solute have higher entropy that reduces with distance from the solute. This indicates that there is a crossover in translational entropy of water molecules around hydrophobic solutes from negative to positive values as the size of the solute is increased. Rotational entropy of water molecules around hydrophobic solutes for all sizes increases with distance from the solute, indicating the absence of crossover in rotational entropy. This makes the crossover in total entropy (translation + rotation) of water molecule happen at much larger size (>1.5 nm) for hydrophobic solutes. Translational entropy of single water molecule scales logarithmically (Str(QH) = C + kB ln V), with the volume V obtained from the ellipsoid of inertia. We further discuss the origin of higher entropy of water around water and show the possibility of recovering the entropy loss of some hypothetical solutes. The results obtained are helpful to understand water entropy behavior around various hydrophobic and charged environments within biomolecules. Finally, we show how our approach can be used to calculate the entropy of the individual water molecules in a protein cavity that may be replaced during ligand binding.

  1. Quantum interference in plasmonic circuits.

    PubMed

    Heeres, Reinier W; Kouwenhoven, Leo P; Zwiller, Valery

    2013-10-01

    Surface plasmon polaritons (plasmons) are a combination of light and a collective oscillation of the free electron plasma at metal/dielectric interfaces. This interaction allows subwavelength confinement of light beyond the diffraction limit inherent to dielectric structures. As a result, the intensity of the electromagnetic field is enhanced, with the possibility to increase the strength of the optical interactions between waveguides, light sources and detectors. Plasmons maintain non-classical photon statistics and preserve entanglement upon transmission through thin, patterned metallic films or weakly confining waveguides. For quantum applications, it is essential that plasmons behave as indistinguishable quantum particles. Here we report on a quantum interference experiment in a nanoscale plasmonic circuit consisting of an on-chip plasmon beamsplitter with integrated superconducting single-photon detectors to allow efficient single plasmon detection. We demonstrate a quantum-mechanical interaction between pairs of indistinguishable surface plasmons by observing Hong-Ou-Mandel (HOM) interference, a hallmark non-classical interference effect that is the basis of linear optics-based quantum computation. Our work shows that it is feasible to shrink quantum optical experiments to the nanoscale and offers a promising route towards subwavelength quantum optical networks.

  2. Oculomotor interference of bimodal distractors.

    PubMed

    Heeman, Jessica; Nijboer, Tanja C W; Van der Stoep, Nathan; Theeuwes, Jan; Van der Stigchel, Stefan

    2016-06-01

    When executing an eye movement to a target location, the presence of an irrelevant distracting stimulus can influence the saccade metrics and latency. The present study investigated the influence of distractors of different sensory modalities (i.e. auditory, visual and audiovisual) which were presented at various distances (i.e. close or remote) from a visual target. The interfering effects of a bimodal distractor were more pronounced in the spatial domain than in the temporal domain. The results indicate that the direction of interference depended on the spatial layout of the visual scene. The close bimodal distractor caused the saccade endpoint and saccade trajectory to deviate towards the distractor whereas the remote bimodal distractor caused a deviation away from the distractor. Furthermore, saccade averaging and trajectory deviation evoked by a bimodal distractor was larger compared to the effects evoked by a unimodal distractor. This indicates that a bimodal distractor evoked stronger spatial oculomotor competition compared to a unimodal distractor and that the direction of the interference depended on the distance between the target and the distractor. Together, these findings suggest that the oculomotor vector to irrelevant bimodal input is enhanced and that the interference by multisensory input is stronger compared to unisensory input.

  3. Critical Temperature Curve in BEC-BCS Crossover

    SciTech Connect

    Burovski, Evgeni; Kozik, Evgeny |; Prokofev, Nikolay ||; Svistunov, Boris |; Troyer, Matthias

    2008-08-29

    The strongly correlated regime of the crossover from Bardeen-Cooper-Schrieffer pairing to Bose-Einstein condensation can be realized by diluting a system of two-component fermions with a short-range attractive interaction. We investigate this system via a novel continuous-space-time diagrammatic determinant Monte Carlo method and determine the universal curve T{sub c}/{epsilon}{sub F} for the transition temperature between the normal and the superfluid states as a function of the scattering length with the maximum on the Bose-Einstein condensation side. At unitarity, we confirm that T{sub c}/{epsilon}{sub F}=0.152(7)

  4. Meige syndrome: double-blind crossover study of sodium valproate.

    PubMed Central

    Snoek, J W; van Weerden, T W; Teelken, A W; van den Burg, W; Lakke, J P

    1987-01-01

    A double-blind crossover study of sodium valproate and placebo was conducted in five patients with Meige syndrome. CSF neurotransmitter studies were performed at the end of each treatment period. GABA levels were not influenced by the administration of sodium valproate. An increase in HVA levels was observed in every patient, which may reflect an increase in central dopaminergic activity. This finding may explain the trend towards clinical deterioration which was observed during treatment with sodium valproate. Sodium valproate appears to be ineffective in Meige syndrome. PMID:3121795

  5. Computational approach to the study of thermal spin crossover phenomena

    SciTech Connect

    Rudavskyi, Andrii; Broer, Ria; Sousa, Carmen

    2014-05-14

    The key parameters associated to the thermally induced spin crossover process have been calculated for a series of Fe(II) complexes with mono-, bi-, and tridentate ligands. Combination of density functional theory calculations for the geometries and for normal vibrational modes, and highly correlated wave function methods for the energies, allows us to accurately compute the entropy variation associated to the spin transition and the zero-point corrected energy difference between the low- and high-spin states. From these values, the transition temperature, T{sub 1/2}, is estimated for different compounds.

  6. Analysis of cross-over studies with missing data.

    PubMed

    Rosenkranz, Gerd K

    2015-08-01

    This paper addresses some aspects of the analysis of cross-over trials with missing or incomplete data. A literature review on the topic reveals that many proposals provide correct results under the missing completely at random assumption while only some consider the more general missing at random situation. It is argued that mixed-effects models have a role in this context to recover some of the missing intra-subject from the inter-subject information, in particular when missingness is ignorable. Eventually, sensitivity analyses to deal with more general missingness mechanisms are presented.

  7. White blood cell counts: reference methodology.

    PubMed

    Chabot-Richards, Devon S; George, Tracy I

    2015-03-01

    Modern hematology laboratories use automated hematology analyzers to perform cell counts. These instruments provide accurate, precise, low-cost differential counts with fast turnaround times. Technologies commonly used include electrical impedance, radiofrequency conductivity, laser light scattering, and cytochemistry. This article reviews the principles of these methodologies and possible sources of error, provides guidance for selecting flagging criteria, and discusses novel, clinically relevant white blood cell parameters provided by new instruments, including immature granulocyte count and granularity index.

  8. Low Background Counting at LBNL

    SciTech Connect

    Smith, A. R.; Thomas, K. J.; Norman, E. B.; Chan, Y. D.; Lesko, K. T.; Hurley, D. L.

    2015-03-24

    The Low Background Facility (LBF) at Lawrence Berkeley National Laboratory in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background cave and remotely at an underground location that historically has operated underground in Oroville, CA, but has recently been relocated to the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K) or common cosmogenic/anthropogenic products, as well as active screening via Neutron Activation Analysis for specific applications. The LBF also provides hosting services for general R&D testing in low background environments on the surface or underground for background testing of detector systems or similar prototyping. A general overview of the facilities, services, and sensitivities is presented. Recent activities and upgrades will also be presented, such as the completion of a 3π anticoincidence shield at the surface station and environmental monitoring of Fukushima fallout. The LBF is open to any users for counting services or collaboration on a wide variety of experiments and projects.

  9. Low Background Counting at LBNL

    DOE PAGES

    Smith, A. R.; Thomas, K. J.; Norman, E. B.; ...

    2015-03-24

    The Low Background Facility (LBF) at Lawrence Berkeley National Laboratory in Berkeley, California provides low background gamma spectroscopy services to a wide array of experiments and projects. The analysis of samples takes place within two unique facilities; locally within a carefully-constructed, low background cave and remotely at an underground location that historically has operated underground in Oroville, CA, but has recently been relocated to the Sanford Underground Research Facility (SURF) in Lead, SD. These facilities provide a variety of gamma spectroscopy services to low background experiments primarily in the form of passive material screening for primordial radioisotopes (U, Th, K)more » or common cosmogenic/anthropogenic products, as well as active screening via Neutron Activation Analysis for specific applications. The LBF also provides hosting services for general R&D testing in low background environments on the surface or underground for background testing of detector systems or similar prototyping. A general overview of the facilities, services, and sensitivities is presented. Recent activities and upgrades will also be presented, such as the completion of a 3π anticoincidence shield at the surface station and environmental monitoring of Fukushima fallout. The LBF is open to any users for counting services or collaboration on a wide variety of experiments and projects.« less

  10. DNA methylation epigenetically silences crossover hot spots and controls chromosomal domains of meiotic recombination in Arabidopsis.

    PubMed

    Yelina, Nataliya E; Lambing, Christophe; Hardcastle, Thomas J; Zhao, Xiaohui; Santos, Bruno; Henderson, Ian R

    2015-10-15

    During meiosis, homologous chromosomes undergo crossover recombination, which is typically concentrated in narrow hot spots that are controlled by genetic and epigenetic information. Arabidopsis chromosomes are highly DNA methylated in the repetitive centromeres, which are also crossover-suppressed. Here we demonstrate that RNA-directed DNA methylation is sufficient to locally silence Arabidopsis euchromatic crossover hot spots and is associated with increased nucleosome density and H3K9me2. However, loss of CG DNA methylation maintenance in met1 triggers epigenetic crossover remodeling at the chromosome scale, with pericentromeric decreases and euchromatic increases in recombination. We used recombination mutants that alter interfering and noninterfering crossover repair pathways (fancm and zip4) to demonstrate that remodeling primarily involves redistribution of interfering crossovers. Using whole-genome bisulfite sequencing, we show that crossover remodeling is driven by loss of CG methylation within the centromeric regions. Using cytogenetics, we profiled meiotic DNA double-strand break (DSB) foci in met1 and found them unchanged relative to wild type. We propose that met1 chromosome structure is altered, causing centromere-proximal DSBs to be inhibited from maturation into interfering crossovers. These data demonstrate that DNA methylation is sufficient to silence crossover hot spots and plays a key role in establishing domains of meiotic recombination along chromosomes.

  11. Identification of CSF fistulas by radionuclide counting

    SciTech Connect

    Yamamoto, Y.; Kunishio, K.; Sunami, N.; Yamamoto, Y.; Satoh, T.; Suga, M.; Asari, S. )

    1990-07-01

    A radionuclide counting method, performed with the patient prone and the neck flexed, was used successfully to diagnose CSF rhinorrhea in two patients. A normal radionuclide ratio (radionuclide counts in pledget/radionuclide counts in 1-ml blood sample) was obtained in 11 normal control subjects. Significance was determined to be a ratio greater than 0.37. Use of radionuclide counting method of determining CSF rhinorrhea is recommended when other methods have failed to locate a site of leakage or when posttraumatic meningitis suggests subclinical CSF rhinorrhea.

  12. Statistical aspects of point count sampling

    USGS Publications Warehouse

    Barker, R.J.; Sauer, J.R.; Ralph, C.J.; Sauer, J.R.; Droege, S.

    1995-01-01

    The dominant feature of point counts is that they do not census birds, but instead provide incomplete counts of individuals present within a survey plot. Considering a simple model for point count sampling, we demon-strate that use of these incomplete counts can bias estimators and testing procedures, leading to inappropriate conclusions. A large portion of the variability in point counts is caused by the incomplete counting, and this within-count variation can be confounded with ecologically meaningful varia-tion. We recommend caution in the analysis of estimates obtained from point counts. Using; our model, we also consider optimal allocation of sampling effort. The critical step in the optimization process is in determining the goals of the study and methods that will be used to meet these goals. By explicitly defining the constraints on sampling and by estimating the relationship between precision and bias of estimators and time spent counting, we can predict the optimal time at a point for each of several monitoring goals. In general, time spent at a point will differ depending on the goals of the study.

  13. Effect of counting errors on immunoassay precision

    SciTech Connect

    Klee, G.G.; Post, G. )

    1989-07-01

    Using mathematical analysis and computer simulation, we studied the effect of gamma scintillation counting error on two radioimmunoassays (RIAs) and an immunoradiometric assay (IRMA). To analyze the propagation of the counting errors into the estimation of analyte concentration, we empirically derived parameters for logit-log data-reduction models for assays of digoxin and triiodothyronine (RIAs) and ferritin (IRMA). The component of the analytical error attributable to counting variability, when expressed as a CV of the analyte concentration, decreased approximately linearly with the inverse of the square root of the maximum counts bound. Larger counting-error CVs were found at lower concentrations for both RIAs and the IRMA. Substantially smaller CVs for overall assay were found when the maximum counts bound progressively increased from 500 to 10,000 counts, but further increases in maximum bound counts resulted in little decrease in overall assay CV except when very low concentrations of analyte were being measured. Therefore, RIA and IRMA systems based in duplicate determinations having at least 10,000 maximum counts bound should have adequate precision, except possibly at very low concentrations.

  14. 7 CFR 1220.625 - Counting requests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN PROMOTION, RESEARCH, AND... ineligibility determinations, the requests shall be counted no later than the 14th business day following...

  15. 7 CFR 1205.28 - Counting.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION... Administrator for Field Operations (DAFO), shall begin counting requests no later than November 30, 2007....

  16. High-Resolution Mapping of Crossover and Non-crossover Recombination Events by Whole-Genome Re-sequencing of an Avian Pedigree.

    PubMed

    Smeds, Linnéa; Mugal, Carina F; Qvarnström, Anna; Ellegren, Hans

    2016-05-01

    Recombination is an engine of genetic diversity and therefore constitutes a key process in evolutionary biology and genetics. While the outcome of crossover recombination can readily be detected as shuffled alleles by following the inheritance of markers in pedigreed families, the more precise location of both crossover and non-crossover recombination events has been difficult to pinpoint. As a consequence, we lack a detailed portrait of the recombination landscape for most organisms and knowledge on how this landscape impacts on sequence evolution at a local scale. To localize recombination events with high resolution in an avian system, we performed whole-genome re-sequencing at high coverage of a complete three-generation collared flycatcher pedigree. We identified 325 crossovers at a median resolution of 1.4 kb, with 86% of the events localized to <10 kb intervals. Observed crossover rates were in excellent agreement with data from linkage mapping, were 52% higher in male (3.56 cM/Mb) than in female meiosis (2.28 cM/Mb), and increased towards chromosome ends in male but not female meiosis. Crossover events were non-randomly distributed in the genome with several distinct hot-spots and a concentration to genic regions, with the highest density in promoters and CpG islands. We further identified 267 non-crossovers, whose location was significantly associated with crossover locations. We detected a significant transmission bias (0.18) in favour of 'strong' (G, C) over 'weak' (A, T) alleles at non-crossover events, providing direct evidence for the process of GC-biased gene conversion in an avian system. The approach taken in this study should be applicable to any species and would thereby help to provide a more comprehensive portray of the recombination landscape across organism groups.

  17. High-Resolution Mapping of Crossover and Non-crossover Recombination Events by Whole-Genome Re-sequencing of an Avian Pedigree

    PubMed Central

    Qvarnström, Anna; Ellegren, Hans

    2016-01-01

    Recombination is an engine of genetic diversity and therefore constitutes a key process in evolutionary biology and genetics. While the outcome of crossover recombination can readily be detected as shuffled alleles by following the inheritance of markers in pedigreed families, the more precise location of both crossover and non-crossover recombination events has been difficult to pinpoint. As a consequence, we lack a detailed portrait of the recombination landscape for most organisms and knowledge on how this landscape impacts on sequence evolution at a local scale. To localize recombination events with high resolution in an avian system, we performed whole-genome re-sequencing at high coverage of a complete three-generation collared flycatcher pedigree. We identified 325 crossovers at a median resolution of 1.4 kb, with 86% of the events localized to <10 kb intervals. Observed crossover rates were in excellent agreement with data from linkage mapping, were 52% higher in male (3.56 cM/Mb) than in female meiosis (2.28 cM/Mb), and increased towards chromosome ends in male but not female meiosis. Crossover events were non-randomly distributed in the genome with several distinct hot-spots and a concentration to genic regions, with the highest density in promoters and CpG islands. We further identified 267 non-crossovers, whose location was significantly associated with crossover locations. We detected a significant transmission bias (0.18) in favour of ‘strong’ (G, C) over ‘weak’ (A, T) alleles at non-crossover events, providing direct evidence for the process of GC-biased gene conversion in an avian system. The approach taken in this study should be applicable to any species and would thereby help to provide a more comprehensive portray of the recombination landscape across organism groups. PMID:27219623

  18. 49 CFR 193.2633 - Interference currents.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...: FEDERAL SAFETY STANDARDS Maintenance § 193.2633 Interference currents. (a) Each component that is subject to electrical current interference must be protected by a continuing program to minimize the... 49 Transportation 3 2012-10-01 2012-10-01 false Interference currents. 193.2633 Section...

  19. 49 CFR 193.2633 - Interference currents.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...: FEDERAL SAFETY STANDARDS Maintenance § 193.2633 Interference currents. (a) Each component that is subject to electrical current interference must be protected by a continuing program to minimize the... 49 Transportation 3 2014-10-01 2014-10-01 false Interference currents. 193.2633 Section...

  20. 49 CFR 193.2633 - Interference currents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...: FEDERAL SAFETY STANDARDS Maintenance § 193.2633 Interference currents. (a) Each component that is subject to electrical current interference must be protected by a continuing program to minimize the... 49 Transportation 3 2011-10-01 2011-10-01 false Interference currents. 193.2633 Section...

  1. Traffic effects on bird counts on North American Breeding Bird Survey routes

    USGS Publications Warehouse

    Griffith, Emily H.; Sauer, John R.; Royle, J. Andrew

    2010-01-01

    The North American Breeding Bird Survey (BBS) is an annual roadside survey used to estimate population change in >420 species of birds that breed in North America. Roadside sampling has been criticized, in part because traffic noise can interfere with bird counts. Since 1997, data have been collected on the numbers of vehicles that pass during counts at each stop. We assessed the effect of traffic by modeling total vehicles as a covariate of counts in hierarchical Poisson regression models used to estimate population change. We selected species for analysis that represent birds detected at low and high abundance and birds with songs of low and high frequencies. Increases in vehicle counts were associated with decreases in bird counts in most of the species examined. The size and direction of these effects remained relatively constant between two alternative models that we analyzed. Although this analysis indicated only a small effect of incorporating traffic effects when modeling roadside counts of birds, we suggest that continued evaluation of changes in traffic at BBS stops should be a component of future BBS analyses.

  2. Source counting in MEG neuroimaging

    NASA Astrophysics Data System (ADS)

    Lei, Tianhu; Dell, John; Magee, Ralphy; Roberts, Timothy P. L.

    2009-02-01

    Magnetoencephalography (MEG) is a multi-channel, functional imaging technique. It measures the magnetic field produced by the primary electric currents inside the brain via a sensor array composed of a large number of superconducting quantum interference devices. The measurements are then used to estimate the locations, strengths, and orientations of these electric currents. This magnetic source imaging technique encompasses a great variety of signal processing and modeling techniques which include Inverse problem, MUltiple SIgnal Classification (MUSIC), Beamforming (BF), and Independent Component Analysis (ICA) method. A key problem with Inverse problem, MUSIC and ICA methods is that the number of sources must be detected a priori. Although BF method scans the source space on a point-to-point basis, the selection of peaks as sources, however, is finally made by subjective thresholding. In practice expert data analysts often select results based on physiological plausibility. This paper presents an eigenstructure approach for the source number detection in MEG neuroimaging. By sorting eigenvalues of the estimated covariance matrix of the acquired MEG data, the measured data space is partitioned into the signal and noise subspaces. The partition is implemented by utilizing information theoretic criteria. The order of the signal subspace gives an estimate of the number of sources. The approach does not refer to any model or hypothesis, hence, is an entirely data-led operation. It possesses clear physical interpretation and efficient computation procedure. The theoretical derivation of this method and the results obtained by using the real MEG data are included to demonstrates their agreement and the promise of the proposed approach.

  3. A Comparison of Methods for Counting Viruses in Aquatic Systems

    PubMed Central

    Bettarel, Yvan; Sime-Ngando, Telesphore; Amblard, Christian; Laveran, Henri

    2000-01-01

    In this study, we compared different methods—including transmission electron microscopy—and various nucleic acid labeling methods in which we used the fluorochromes 4′,6′-diamidino-2-phenylindole (DAPI), 4-[3-methyl-2,3-dihydro-(benzo-1,3-oxazole)-2-methylmethyledene]-1-(3′-trimethyl ammoniumpropyl)-quinilinium diioide (YOPRO-1), and SYBR Green I, which can be detected by epifluorescence microscopy (EM), for counting viruses in samples obtained from freshwater ecosystems whose trophic status varied and from a culture of T7 phages. From a quantitative and qualitative viewpoint, our results showed that the greatest efficiency for all ecosystems was obtained when we used the EM counting protocol in which YOPRO-1 was the label, as this fluorochrome exhibited strong and very stable fluorescence. A modification of the original protocol in which YOPRO-1 was used is recommended, because this modification makes the protocol faster and allows it to be used for routine analysis of fixed samples. Because SYBR Green I fades very quickly, the use of this fluorochrome is not recommended for systems in which the viral content is very high (>108 particles/ml), such as treated domestic sewage effluents. Experiments in which we used DNase and RNase revealed that the number of viruses determined by EM was slightly overestimated (by approximately 15%) because of interference caused by the presence of free nucleic acids. PMID:10831400

  4. Metal-to-insulator crossover in alkali doped zeolite

    PubMed Central

    Igarashi, Mutsuo; Jeglič, Peter; Krajnc, Andraž; Žitko, Rok; Nakano, Takehito; Nozue, Yasuo; Arčon, Denis

    2016-01-01

    We report a systematic nuclear magnetic resonance investigation of the 23Na spin-lattice relaxation rate, 1/T1, in sodium loaded low-silica X (LSX) zeolite, Nan/Na12-LSX, for various loading levels of sodium atoms n across the metal-to-insulator crossover. For high loading levels of n ≥ 14.2, 1/T1T shows nearly temperature-independent behaviour between 10 K and 25 K consistent with the Korringa relaxation mechanism and the metallic ground state. As the loading levels decrease below n ≤ 11.6, the extracted density of states (DOS) at the Fermi level sharply decreases, although a residual DOS at Fermi level is still observed even in the samples that lack the metallic Drude-peak in the optical reflectance. The observed crossover is a result of a complex loading-level dependence of electric potential felt by the electrons confined to zeolite cages, where the electronic correlations and disorder both play an important role. PMID:26725368

  5. Spin-Crossover Materials towards Microwave Radiation Switches

    PubMed Central

    Kucheriv, Olesia I.; Oliynyk, Viktor V.; Zagorodnii, Volodymyr V.; Launets, Vilen L.; Gural’skiy, Il’ya A.

    2016-01-01

    Microwave electromagnetic radiation that ranges from one meter to one millimetre wavelengths is finding numerous applications for wireless communication, navigation and detection, which makes materials able to tune microwave radiation getting widespread interest. Here we offer a new way to tune GHz frequency radiation by using spin-crossover complexes that are known to change their various physical properties under the influence of diverse external stimuli. As a result of electronic re-configuration process, microwave absorption properties differ for high spin and low spin forms of the complex. The evolution of a microwave absorption spectrum for the switchable compound within the region of thermal transition indicates that the high-spin and the low-spin forms are characterized by a different attenuation of electromagnetic waves. Absorption and reflection coefficients were found to be higher in the high-spin state comparing to the low-spin state. These results reveal a considerable potential for the implementation of spin-crossover materials into different elements of microwave signal switching and wireless communication. PMID:27910956

  6. Recombination patterns in maize reveal limits to crossover homeostasis.

    PubMed

    Sidhu, Gaganpreet K; Fang, Celestia; Olson, Mischa A; Falque, Matthieu; Martin, Olivier C; Pawlowski, Wojciech P

    2015-12-29

    During meiotic recombination, double-strand breaks (DSBs) are formed in chromosomal DNA and then repaired as either crossovers (COs) or non-crossovers (NCOs). In most taxa, the number of DSBs vastly exceeds the number of COs. COs are required for generating genetic diversity in the progeny, as well as proper chromosome segregation. Their formation is tightly controlled so that there is at least one CO per pair of homologous chromosomes whereas the maximum number of COs per chromosome pair is fairly limited. One of the main mechanisms controlling the number of recombination events per meiosis is CO homeostasis, which maintains a stable CO number even when the DSB number is dramatically altered. The existence of CO homeostasis has been reported in several species, including mouse, yeast, and Caenorhabditis elegans. However, it is not known whether homeostasis exists in the same form in all species. In addition, the studies of homeostasis have been conducted using mutants and/or transgenic lines exhibiting fairly severe meiotic phenotypes, and it is unclear how important homeostasis is under normal physiological conditions. We found that, in maize, CO control is robust only to ensure one CO per chromosome pair. However, once this limit is reached, the CO number is linearly related to the DSB number. We propose that CO control is a multifaceted process whose different aspects have a varying degree of importance in different species.

  7. Low Crossover Polymer Electrolyte Membranes for Direct Methanol Fuel Cells

    NASA Technical Reports Server (NTRS)

    Prakash, G. K. Surya; Smart, Marshall; Atti, Anthony R.; Olah, George A.; Narayanan, S. R.; Valdez, T.; Surampudi, S.

    1996-01-01

    Direct Methanol Fuel Cells (DMFC's) using polymer electrolyte membranes are promising power sources for portable and vehicular applications. State of the art technology using Nafion(R) 117 membranes (Dupont) are limited by high methanol permeability and cost, resulting in reduced fuel cell efficiencies and impractical commercialization. Therefore, much research in the fuel cell field is focused on the preparation and testing of low crossover and cost efficient polymer electrolyte membranes. The University of Southern California in cooperation with the Jet Propulsion Laboratory is focused on development of such materials. Interpenetrating polymer networks are an effective method used to blend polymer systems without forming chemical links. They provide the ability to modify physical and chemical properties of polymers by optimizing blend compositions. We have developed a novel interpenetrating polymer network based on poly (vinyl - difluoride)/cross-linked polystyrenesulfonic acid polymer composites (PVDF PSSA). Sulfonation of polystyrene accounts for protonic conductivity while the non-polar, PVDF backbone provides structural integrity in addition to methanol rejection. Precursor materials were prepared and analyzed to characterize membrane crystallinity, stability and degree of interpenetration. USC JPL PVDF-PSSA membranes were also characterized to determine methanol permeability, protonic conductivity and sulfur distribution. Membranes were fabricated into membrane electrode assemblies (MEA) and tested for single cell performance. Tests include cell performance over a wide range of temperatures (20 C - 90 C) and cathode conditions (ambient Air/O2). Methanol crossover values are measured in situ using an in-line CO2 analyzer.

  8. Chaos based crossover and mutation for securing DICOM image.

    PubMed

    Ravichandran, Dhivya; Praveenkumar, Padmapriya; Balaguru Rayappan, John Bosco; Amirtharajan, Rengarajan

    2016-05-01

    This paper proposes a novel encryption scheme based on combining multiple chaotic maps to ensure the safe transmission of medical images. The proposed scheme uses three chaotic maps namely logistic, tent and sine maps. To achieve an efficient encryption, the proposed chao-cryptic system employs a bio-inspired crossover and mutation units to confuse and diffuse the Digital Imaging and Communications in Medicine (DICOM) image pixels. The crossover unit extensively permutes the image pixels row-wise and column-wise based on the chaotic key streams generated from the Combined Logistic-Tent (CLT) system. Prior to mutation, the pixels of the crossed over image are decomposed into two images with reduced bit depth. The decomposed images are then mutated by XOR operation with quantized chaotic sequences from Combined Logistic-Sine (CLS) system. In order to validate the sternness of the proposed algorithm, the developed chao-cryptic scheme is subjected to various security analyses such as statistical, differential, key space, key sensitivity, intentional cropping attack and chosen plaintext attack analyses. The experimental results prove the proposed DICOM cryptosystem has achieved a desirable amount of protection for real time medical image security applications.

  9. Dimensional crossover of a boson gas in multilayers

    SciTech Connect

    Salas, P.; Sevilla, F. J.; Fortes, M.; Solis, M. A.; Llano, M. de; Camacho, A.

    2010-09-15

    We obtain the thermodynamic properties for a noninteracting Bose gas constrained on multilayers modeled by a periodic Kronig-Penney delta potential in one direction and allowed to be free in the other two directions. We report Bose-Einstein condensation (BEC) critical temperatures, chemical potential, internal energy, specific heat, and entropy for different values of a dimensionless impenetrability P{>=}0 between layers. The BEC critical temperature T{sub c} coincides with the ideal gas BEC critical temperature T{sub 0} when P=0 and rapidly goes to zero as P increases to infinity for any finite interlayer separation. The specific heat C{sub V} as a function of absolute temperature T for finite P and plane separation a exhibits one minimum and one or two maxima in addition to the BEC, for temperatures larger than that of BEC T{sub c}. This highlights the effects due to particle confinement. We then discuss a distinctive dimensional crossover of the system through the specific heat behavior driven by the magnitude of P. For Tcrossover is revealed by a change in slope of logC{sub V}(T) and when T>T{sub c}, it is exhibited by a broad minimum in C{sub V}(T).

  10. Spin-Crossover Materials towards Microwave Radiation Switches.

    PubMed

    Kucheriv, Olesia I; Oliynyk, Viktor V; Zagorodnii, Volodymyr V; Launets, Vilen L; Gural'skiy, Il'ya A

    2016-12-02

    Microwave electromagnetic radiation that ranges from one meter to one millimetre wavelengths is finding numerous applications for wireless communication, navigation and detection, which makes materials able to tune microwave radiation getting widespread interest. Here we offer a new way to tune GHz frequency radiation by using spin-crossover complexes that are known to change their various physical properties under the influence of diverse external stimuli. As a result of electronic re-configuration process, microwave absorption properties differ for high spin and low spin forms of the complex. The evolution of a microwave absorption spectrum for the switchable compound within the region of thermal transition indicates that the high-spin and the low-spin forms are characterized by a different attenuation of electromagnetic waves. Absorption and reflection coefficients were found to be higher in the high-spin state comparing to the low-spin state. These results reveal a considerable potential for the implementation of spin-crossover materials into different elements of microwave signal switching and wireless communication.

  11. More than one dynamic crossover in protein hydration water

    PubMed Central

    Mazza, Marco G.; Stokely, Kevin; Pagnotta, Sara E.; Bruni, Fabio; Stanley, H. Eugene; Franzese, Giancarlo

    2011-01-01

    Studies of liquid water in its supercooled region have helped us better understand the structure and behavior of water. Bulk water freezes at its homogeneous nucleation temperature (approximately 235 K), but protein hydration water avoids this crystallization because each water molecule binds to a protein. Here, we study the dynamics of the hydrogen bond (HB) network of a percolating layer of water molecules and compare the measurements of a hydrated globular protein with the results of a coarse-grained model that successfully reproduces the properties of hydration water. Using dielectric spectroscopy, we measure the temperature dependence of the relaxation time of proton charge fluctuations. These fluctuations are associated with the dynamics of the HB network of water molecules adsorbed on the protein surface. Using Monte Carlo simulations and mean-field calculations, we study the dynamics and thermodynamics of the model. Both experimental and model analyses are consistent with the interesting possibility of two dynamic crossovers, (i) at approximately 252 K and (ii) at approximately 181 K. Because the experiments agree with the model, we can relate the two crossovers to the presence at ambient pressure of two specific heat maxima. The first is caused by fluctuations in the HB formation, and the second, at a lower temperature, is due to the cooperative reordering of the HB network. PMID:22135473

  12. More than one dynamic crossover in protein hydration water.

    PubMed

    Mazza, Marco G; Stokely, Kevin; Pagnotta, Sara E; Bruni, Fabio; Stanley, H Eugene; Franzese, Giancarlo

    2011-12-13

    Studies of liquid water in its supercooled region have helped us better understand the structure and behavior of water. Bulk water freezes at its homogeneous nucleation temperature (approximately 235 K), but protein hydration water avoids this crystallization because each water molecule binds to a protein. Here, we study the dynamics of the hydrogen bond (HB) network of a percolating layer of water molecules and compare the measurements of a hydrated globular protein with the results of a coarse-grained model that successfully reproduces the properties of hydration water. Using dielectric spectroscopy, we measure the temperature dependence of the relaxation time of proton charge fluctuations. These fluctuations are associated with the dynamics of the HB network of water molecules adsorbed on the protein surface. Using Monte Carlo simulations and mean-field calculations, we study the dynamics and thermodynamics of the model. Both experimental and model analyses are consistent with the interesting possibility of two dynamic crossovers, (i) at approximately 252 K and (ii) at approximately 181 K. Because the experiments agree with the model, we can relate the two crossovers to the presence at ambient pressure of two specific heat maxima. The first is caused by fluctuations in the HB formation, and the second, at a lower temperature, is due to the cooperative reordering of the HB network.

  13. Dimensional crossover and universal roughness distributions in Barkhausen noise.

    PubMed

    de Queiroz, S L A

    2004-02-01

    We investigate the dimensional crossover of scaling properties of avalanches (domain-wall jumps) in a single-interface model, used for the description of Barkhausen noise in disordered magnets. By varying the transverse aspect ratio A=L(y)/L(x) of simulated samples, the system dimensionality changes from two to three. We find that perturbing away from d=2 is a relevant field. The exponent tau characterizing the power-law scaling of avalanche distributions varies between 1.06(1) for d=2 and 1.275(15) for d=3, according to a crossover function f(x), x identical with (L-1x)(phi)/A, with phi=0.95(3). We discuss the possible relevance of our results to the interpretation of thin-film measurements of Barkhausen noise. We also study the probability distributions of interface roughness, sampled among successive equilibrium configurations in the Barkhausen noise regime. Attempts to fit our data to the class of universality distributions associated to 1/f(alpha) noise give alpha approximately 1-1.1 for d=2 and 3 (provided that suitable boundary conditions are used in the latter case).

  14. Analysis of Poisson frequency data under a simple crossover trial.

    PubMed

    Lui, Kung-Jong; Chang, Kuang-Chao

    2016-02-01

    When the frequency of occurrence for an event of interest follows a Poisson distribution, we develop asymptotic and exact procedures for testing non-equality, non-inferiority and equivalence, as well as asymptotic and exact interval estimators for the ratio of mean frequencies between two treatments under a simple crossover design. Using Monte Carlo simulations, we evaluate the performance of these test procedures and interval estimators in a variety of situations. We note that all asymptotic test procedures developed here can generally perform well with respect to Type I error and can be preferable to the exact test procedure with respect to power if the number of patients per group is moderate or large. We further find that in these cases the asymptotic interval estimator with the logarithmic transformation can be more precise than the exact interval estimator without sacrificing the accuracy with respect to the coverage probability. However, the exact test procedure and exact interval estimator can be of use when the number of patients per group is small. We use a double-blind randomized crossover trial comparing salmeterol with a placebo in exacerbations of asthma to illustrate the practical use of these estimators.

  15. Crossover from attractive to repulsive Casimir forces and vice versa.

    PubMed

    Schmidt, Felix M; Diehl, H W

    2008-09-05

    Systems described by an O(n) symmetrical varphi;{4} Hamiltonian are considered in a d-dimensional film geometry at their bulk critical points. The critical Casimir forces between the film's boundary planes B_{j}, j=1,2, are investigated as functions of film thickness L for generic symmetry-preserving boundary conditions partial differential_{n}phi=c[over composite function]_{j}phi. The L-dependent part of the reduced excess free energy per cross-sectional area takes the scaling form f_{res} approximately D(c_{1}L;{Phi/nu},c_{2}L;{Phi/nu})/L;{d-1} when d<4, where c_{i} are scaling fields associated with the variables c[over composite function]_{i} and Phi is a surface crossover exponent. Explicit two-loop renormalization group results for the function D(c_{1},c_{2}) at d=4- dimensions are presented. These show that (i) the Casimir force can have either sign, depending on c_{1} and c_{2}, and (ii) for appropriate choices of the enhancements c[over composite function]_{j}, crossovers from attraction to repulsion and vice versa occur as L increases.

  16. Bcs-Bec Crossover Without Appeal to Scattering Length Theory

    NASA Astrophysics Data System (ADS)

    Malik, G. P.

    2014-01-01

    BCS-BEC (an acronym formed from Bardeen, Cooper, Schrieffer and Bose-Einstein condensation) crossover physics has customarily been addressed in the framework of the scattering length theory (SLT), which requires regularization/renormalization of equations involving infinities. This paper gives a frame by frame picture, as it were, of the crossover scenario without appealing to SLT. While we believe that the intuitive approach followed here will make the subject accessible to a wider readership, we also show that it sheds light on a feature that has not been under the purview of the customary approach: the role of the hole-hole scatterings vis-à-vis the electron-electron scatterings as one goes from the BCS to the BEC end. More importantly, we show that there are critical values of the concentration (n)and the interaction parameter (λ) at which the condensation of Cooper pairs takes place; this is a finding in contrast with the view that such pairs are automatically condensed.

  17. Metal-to-insulator crossover in alkali doped zeolite

    NASA Astrophysics Data System (ADS)

    Igarashi, Mutsuo; Jeglič, Peter; Krajnc, Andraž; Žitko, Rok; Nakano, Takehito; Nozue, Yasuo; Arčon, Denis

    2016-01-01

    We report a systematic nuclear magnetic resonance investigation of the 23Na spin-lattice relaxation rate, 1/T1, in sodium loaded low-silica X (LSX) zeolite, Nan/Na12-LSX, for various loading levels of sodium atoms n across the metal-to-insulator crossover. For high loading levels of n ≥ 14.2, 1/T1T shows nearly temperature-independent behaviour between 10 K and 25 K consistent with the Korringa relaxation mechanism and the metallic ground state. As the loading levels decrease below n ≤ 11.6, the extracted density of states (DOS) at the Fermi level sharply decreases, although a residual DOS at Fermi level is still observed even in the samples that lack the metallic Drude-peak in the optical reflectance. The observed crossover is a result of a complex loading-level dependence of electric potential felt by the electrons confined to zeolite cages, where the electronic correlations and disorder both play an important role.

  18. IETS and quantum interference: Propensity rules in the presence of an interference feature

    SciTech Connect

    Lykkebo, Jacob; Solomon, Gemma C.; Gagliardi, Alessio; Pecchia, Alessandro

    2014-09-28

    Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low current or a particular line shape in current-voltage curves, depending on the position of the interference feature. Second, we consider how inelastic electron tunneling spectroscopy can be used to probe the presence of an interference feature by identifying vibrational modes that are selectively suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference.

  19. Corynebacterium glutamicum Metabolic Engineering with CRISPR Interference (CRISPRi)

    PubMed Central

    2016-01-01

    Corynebacterium glutamicum is an important organism for the industrial production of amino acids. Metabolic pathways in this organism are usually engineered by conventional methods such as homologous recombination, which depends on rare double-crossover events. To facilitate the mapping of gene expression levels to metabolic outputs, we applied CRISPR interference (CRISPRi) technology using deactivated Cas9 (dCas9) to repress genes in C. glutamicum. We then determined the effects of target repression on amino acid titers. Single-guide RNAs directing dCas9 to specific targets reduced expression of pgi and pck up to 98%, and of pyk up to 97%, resulting in titer enhancement ratios of l-lysine and l-glutamate production comparable to levels achieved by gene deletion. This approach for C. glutamicum metabolic engineering, which only requires 3 days, indicates that CRISPRi can be used for quick and efficient metabolic pathway remodeling without the need for gene deletions or mutations and subsequent selection. PMID:26829286

  20. Wall interference assessment and corrections

    NASA Technical Reports Server (NTRS)

    Newman, P. A.; Kemp, W. B., Jr.; Garriz, J. A.

    1989-01-01

    Wind tunnel wall interference assessment and correction (WIAC) concepts, applications, and typical results are discussed in terms of several nonlinear transonic codes and one panel method code developed for and being implemented at NASA-Langley. Contrasts between 2-D and 3-D transonic testing factors which affect WIAC procedures are illustrated using airfoil data from the 0.3 m Transonic Cryogenic Tunnel and Pathfinder 1 data from the National Transonic Facility. Initial results from the 3-D WIAC codes are encouraging; research on and implementation of WIAC concepts continue.

  1. Structured interference optical coherence tomography.

    PubMed

    Yi, Ji; Wei, Qing; Zhang, Hao F; Backman, Vadim

    2012-08-01

    We developed a structured interference optical coherence tomography (SIOCT) to enhance the lateral resolution beyond the diffraction limit. A sinusoidal pattern is created on the interferometric beam with the reference intensity temporally modulated. In the Fourier domain, the high spatial frequencies are shifted into the detectable range, which enhances the lateral resolution beyond the diffraction limit by a factor of 2. The lateral resolution of SIOCT was characterized in our study as ~5.5 μm, surpassing the diffraction limit ~9.6 μm as in conventional Fourier-domain optical coherence tomography. SIOCT was demonstrated on phantoms and ex vivo adipose tissues.

  2. Long working distance interference microscope

    DOEpatents

    Sinclair, Michael B.; DeBoer, Maarten P.; Smith, Norman F.

    2004-04-13

    Disclosed is a long working distance interference microscope suitable for three-dimensional imaging and metrology of MEMS devices and test structures on a standard microelectronics probe station. The long working distance of 10-30 mm allows standard probes or probe cards to be used. This enables nanometer-scale 3-D height profiles of MEMS test structures to be acquired across an entire wafer. A well-matched pair of reference/sample objectives is not required, significantly reducing the cost of this microscope, as compared to a Linnik microinterferometer.

  3. 2008 KidsCount in Colorado!

    ERIC Educational Resources Information Center

    Colorado Children's Campaign, 2008

    2008-01-01

    "KidsCount in Colorado!" is an annual publication of the Colorado Children's Campaign, which provides the best available state- and county-level data to measure and track the education, health and general well-being of the state's children. KidsCount in Colorado! informs policy debates and community discussions, serving as a valuable…

  4. Is It Counting, or Is It Adding?

    ERIC Educational Resources Information Center

    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…

  5. "Knots on a Counting Rope": Teaching Stories.

    ERIC Educational Resources Information Center

    Key, Daphne

    2001-01-01

    Argues that reflecting on important "marker" stories in people's lives by using counting ropes (based on the children's book "Knots on a Counting Rope" by Bill Martin Jr. and John Archambault) helps students and teachers make sense of their complex worlds. Describes how they are used in the author's language arts methods course. Describes a…

  6. Photon counts from stellar occultation sources

    NASA Technical Reports Server (NTRS)

    Buglia, James J.

    1987-01-01

    The feasibility of using stars as radiation sources for Earth atmospheric occultation experiments is investigated. Exoatmospheric photon counts of the order of 10 to the 6th power photons/sq cm/sec are realized for the 15 visually brightest stars. Most photon counts appear to be marginally detectable unless photomultiplier or cascade detection devices can be used.

  7. 2013 Kids Count in Colorado! Community Matters

    ERIC Educational Resources Information Center

    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…

  8. Early Concepts of Number and Counting

    ERIC Educational Resources Information Center

    Box, Katherine; Scott, Paul

    2004-01-01

    Before primitive man had grasped the concept of number, the written word or even speech, he was able to count. This was important for keeping track of food supplies, sending messages, trading between villages and even keeping track of how many animals were in their herd. Counting was done in various ways, but in all cases, the underlying principle…

  9. Kids Count in Delaware, Families Count in Delaware: Fact Book, 2002.

    ERIC Educational Resources Information Center

    Delaware Univ., Newark. Kids Count in Delaware.

    This Kids Count Fact Book is combined with the Families Count Fact Book to provide information on statewide trends affecting children and families in Delaware. The Kids Count statistical profile is based on 11 main indicators of child well-being: (1) births to teens 15-17 years; (2) births to teens 10 to 14 years; (3) low birth weight babies; (3)…

  10. Kids Count in Delaware: Fact Book 1999 [and] Families Count in Delaware: Fact Book, 1999.

    ERIC Educational Resources Information Center

    Delaware Univ., Newark. Kids Count in Delaware.

    This Kids Count Fact Book is combined with the Families Count Fact Book to provide information on statewide trends affecting children and families in Delaware. The Kids Count 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; (5) teen…

  11. Motor interference in interactive contexts

    PubMed Central

    Chinellato, Eris; Castiello, Umberto; Sartori, Luisa

    2015-01-01

    Action observation and execution share overlapping neural substrates, so that simultaneous activation by observation and execution modulates motor performance. Previous literature on simple prehension tasks has revealed that motor influence can be two-sided: facilitation for observed and performed congruent actions and interference for incongruent actions. But little is known of the specific modulations of motor performance in complex forms of interaction. Is it possible that the very same observed movement can lead either to interference or facilitation effects on a temporally overlapping congruent executed action, depending on the context? To answer this question participants were asked to perform a reach-to-grasp movement adopting a precision grip (PG) while: (i) observing a fixation cross, (ii) observing an actor performing a PG with interactive purposes, (iii) observing an actor performing a PG without interactive purposes. In particular, in the interactive condition the actor was shown trying to pour some sugar on a large cup located out of her reach but close to the participant watching the video, thus eliciting in reaction a complementary whole-hand grasp. Notably, fine-grained kinematic analysis for this condition revealed a specific delay in the grasping and reaching components and an increased trajectory deviation despite the observed and executed movement’s congruency. Moreover, early peaks of trajectory deviation seem to indicate that socially relevant stimuli are acknowledged by the motor system very early. These data suggest that interactive contexts can determine a prompt modulation of stimulus–response compatibility effects. PMID:26113835

  12. Modal interference in spiky nanoshells.

    PubMed

    Hastings, Simon P; Qian, Zhaoxia; Swanglap, Pattanawit; Fang, Ying; Engheta, Nader; Park, So-Jung; Link, Stephan; Fakhraai, Zahra

    2015-05-04

    Near-field enhancement of the electric field by metallic nanostructures is important in non-linear optical applications such as surface enhanced Raman scattering. One approach to producing strong localization of the electric field is to couple a dark, non-radiating plasmonic mode with a broad dipolar resonator that is detectable in the far-field. However, characterizing or predicting the degree of the coupling between these modes for a complicated nanostructure can be quite challenging. Here we develop a robust method to solve the T-matrix, the matrix that predicts the scattered electric fields of the incident light, based on finite-difference time-domain (FDTD) simulations and least square fitting algorithms. This method allows us to simultaneously calculate the T-matrix for a broad spectral range. Using this method, the coupling between the electric dipole and quadrupole modes of spiky nanoshells is evaluated. It is shown that the built-in disorder in the structure of these nanoshells allows for coupling between the dipole modes of various orientations as well as coupling between the dipole and the quadrupole modes. A coupling strength of about 5% between these modes can explain the apparent interference features observed in the single particle scattering spectrum. This effect is experimentally verified by single particle backscattering measurements of spiky nanoshells. The modal interference in disordered spiky nanoshells can explain the origin of the spectrally broad quadrupole resonances that result in strong Quadrupole Enhanced Raman Scattering (QERS) in these nanoparticles.

  13. Natural variation and dosage of the HEI10 meiotic E3 ligase control Arabidopsis crossover recombination

    PubMed Central

    Ziolkowski, Piotr A.; Underwood, Charles J.; Lambing, Christophe; Martinez-Garcia, Marina; Lawrence, Emma J.; Ziolkowska, Liliana; Griffin, Catherine; Choi, Kyuha; Franklin, F. Chris H.; Martienssen, Robert A.; Henderson, Ian R.

    2017-01-01

    During meiosis, homologous chromosomes undergo crossover recombination, which creates genetic diversity and balances homolog segregation. Despite these critical functions, crossover frequency varies extensively within and between species. Although natural crossover recombination modifier loci have been detected in plants, causal genes have remained elusive. Using natural Arabidopsis thaliana accessions, we identified two major recombination quantitative trait loci (rQTLs) that explain 56.9% of crossover variation in Col×Ler F2 populations. We mapped rQTL1 to semidominant polymorphisms in HEI10, which encodes a conserved ubiquitin E3 ligase that regulates crossovers. Null hei10 mutants are haploinsufficient, and, using genome-wide mapping and immunocytology, we show that transformation of additional HEI10 copies is sufficient to more than double euchromatic crossovers. However, heterochromatic centromeres remained recombination-suppressed. The strongest HEI10-mediated crossover increases occur in subtelomeric euchromatin, which is reminiscent of sex differences in Arabidopsis recombination. Our work reveals that HEI10 naturally limits Arabidopsis crossovers and has the potential to influence the response to selection. PMID:28223312

  14. A Cross-Over Experimental Design for Testing Audiovisual Training Materials.

    ERIC Educational Resources Information Center

    Stolovitch, Harold D.; Bordeleau, Pierre

    This paper contains a description of the cross-over type of experimental design as well as a case study of its use in field testing audiovisual materials related to teaching handicapped children. Increased efficiency is an advantage of the cross-over design, while difficulty in selecting similar format audiovisual materials for field testing is a…

  15. Methods for adjusting for bias due to crossover in oncology trials.

    PubMed

    Ishak, K Jack; Proskorovsky, Irina; Korytowsky, Beata; Sandin, Rickard; Faivre, Sandrine; Valle, Juan

    2014-06-01

    Trials of new oncology treatments often involve a crossover element in their design that allows patients receiving the control treatment to crossover to receive the experimental treatment at disease progression or when sufficient evidence about the efficacy of the new treatment is achieved. Crossover leads to contamination of the initial randomized groups due to a mixing of the effects of the control and experimental treatments in the reference group. This is further complicated by the fact that crossover is often a very selective process whereby patients who switch treatment have a different prognosis than those who do not. Standard statistical techniques, including those that attempt to account for the treatment switch, cannot fully adjust for the bias introduced by crossover. Specialized methods such as rank-preserving structural failure time (RPSFT) models and inverse probability of censoring weighted (IPCW) analyses are designed to deal with selective treatment switching and have been increasingly applied to adjust for crossover. We provide an overview of the crossover problem and highlight circumstances under which it is likely to cause bias. We then describe the RPSFT and IPCW methods and explain how these methods adjust for the bias, highlighting the assumptions invoked in the process. Our aim is to facilitate understanding of these complex methods using a case study to support explanations. We also discuss the implications of crossover adjustment on cost-effectiveness results.

  16. 49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Additional operational requirements for hand... hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule which... requirements of this section. (b) Hand-operated crossover switches, generally. Both hand-operated switches of...

  17. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Hand-operated switches, including crossover... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...) General. Employees operating or verifying the position of a hand-operated switch shall: (1) Conduct...

  18. 49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Additional operational requirements for hand... hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule which... requirements of this section. (b) Hand-operated crossover switches, generally. Both hand-operated switches of...

  19. 49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Additional operational requirements for hand... hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule which... requirements of this section. (b) Hand-operated crossover switches, generally. Both hand-operated switches of...

  20. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Hand-operated switches, including crossover... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...) General. Employees operating or verifying the position of a hand-operated switch shall: (1) Conduct...

  1. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Hand-operated switches, including crossover... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...) General. Employees operating or verifying the position of a hand-operated switch shall: (1) Conduct...

  2. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Hand-operated switches, including crossover switches. 218.103 Section 218.103 Transportation Other Regulations Relating to Transportation (Continued... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches....

  3. 49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-operated crossover switches. 218.107 Section 218.107 Transportation Other Regulations Relating to... PRACTICES Handling Equipment, Switches, and Fixed Derails § 218.107 Additional operational requirements for hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule...

  4. 49 CFR 236.203 - Hand operated crossover between main tracks; protection.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of the following: (a) An arrangement of one or more track circuits and switch circuit controllers, (b) Facing point locks on both switches of the crossover, with both locks operated by a single lever, or (c) Electric locking of the switches of the crossover. Signals governing movements over either switch...

  5. 49 CFR 218.107 - Additional operational requirements for hand-operated crossover switches.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-operated crossover switches. 218.107 Section 218.107 Transportation Other Regulations Relating to... PRACTICES Handling Equipment, Switches, and Fixed Derails § 218.107 Additional operational requirements for hand-operated crossover switches. (a) Each railroad shall adopt and comply with an operating rule...

  6. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Hand-operated switches, including crossover switches. 218.103 Section 218.103 Transportation Other Regulations Relating to Transportation (Continued... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches....

  7. 50 CFR 660.220 - Fixed gear fishery-crossover provisions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Fixed gear fishery-crossover provisions... West Coast Groundfish-Limited Entry Fixed Gear Fisheries § 660.220 Fixed gear fishery—crossover... fixed gear fishery....

  8. Spillover and Crossover of Exhaustion and Life Satisfaction among Dual-Earner Parents

    ERIC Educational Resources Information Center

    Demerouti, Evangelia; Bakker, Arnold B.; Schaufeli, Wilmar B.

    2005-01-01

    This study integrates spillover research of stress transferring from work to home and crossover research of strains transferring from one spouse to another. A spillover and crossover model was tested among 191 (couples of) dual-earner parents. For both males and females, it was hypothesized that (self-reported and partners' rating of)…

  9. 50 CFR 660.320 - Open access fishery-crossover provisions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Open access fishery-crossover provisions... West Coast Groundfish-Open Access Fisheries § 660.320 Open access fishery—crossover provisions. (a) Operating in both limited entry and open access fisheries. See provisions at § 660.60, subpart C....

  10. Hematological clozapine monitoring with a point-of-care device: a randomized cross-over trial.

    PubMed

    Nielsen, Jimmi; Thode, Dorrit; Stenager, Elsebeth; Andersen, Kristian Øllegaard; Sondrup, Ulla; Hansen, Tine N; Munk, Anne Marie; Lykkegaard, Signe; Gosvig, Annette; Petrov, Igor; le Quach, Phuong

    2012-06-01

    Clozapine remains the drug of choice for patients with treatment-resistant schizophrenia, who show a response rate of about 50% despite their unresponsiveness to other antipsychotics. Although treatment with clozapine can lead to considerable savings on bed days, the drug is underutilized for several reasons, perhaps most importantly because of the mandatory hematological monitoring. The Chempaq Express Blood Counter (Chempaq XBC) is a point-of-care device providing counts of white blood cells (WBC) and granulocytes based on a capillary blood sampling. A randomized cross-over trial design was used comparing capillary blood sampling using a point-of-care device with traditional venous blood sampling. Patients were randomized to two sequences starting with either capillary or venous blood sampling followed by a repeated sequence. Primary outcome was measured on a 10-cm visual analog scale. Eighty-five patients were included in the test. Eight (9.4%) dropped out before completion. Patients indicated that they found capillary blood monitoring less painful than venous sampling (VAS ratings: 0.55 cm 25-75 percentiles: 0.1-1.4 cm vs. 1.75 cm 25-75 percentiles: 0.7-2.6, p<0.001). They also felt less inconvenienced by the point-of-care method than the traditional blood sampling, which involved traveling to the laboratory clinical (0.3 cm 25-75 percentiles: 0.05-0.7 vs. 2.3 cm 25-75 percentiles: 0.75-4.5, p<0.001). For hematological monitoring of clozapine patients a point-of-care device based on capillary blood sampling is better tolerated than traditional venous blood sampling.

  11. Biases in Attentional Orientation and Magnitude Estimation Explain Crossover: Neglect is a Disorder of Both

    PubMed Central

    Mennemeier, Mark; Pierce, Christopher A.; Chatterjee, Anjan; Anderson, Britt; Jewell, George; Dowler, Rachael; Woods, Adam J.; Glenn, Tannahill; Mark, Victor W.

    2015-01-01

    Crossover refers to a pattern of performance on the line bisection test in which short lines are bisected on the side opposite the true center of long lines. Although most patients with spatial neglect demonstrate crossover, contemporary theories of neglect cannot explain it. In contrast, we show that blending the psychophysical construct of magnitude estimation with neglect theory not only explains crossover, but also addresses a quantitative feature of neglect that is independent of spatial deficits. We report a prospective validation study of the orientation/estimation hypothesis of crossover. Forty subjects (17 patients with and without neglect following unilateral brain injury and 23 normal controls) completed four experiments that examined crossover using line bisection, line bisection with cueing, and reproducing line lengths from both memory and a standard. Replicating earlier findings, all except one subject group exhibited crossover on the standard line bisection test, all groups showed a spontaneous preference to orient attention to one end of the lines, and all groups overestimated the length of short lines and underestimated long lines. Biases in attentional orientation and magnitude estimation are exaggerated in patients with neglect. The truly novel finding of this study occurred when, after removing the line from the bisection task, the direction of crossover was completely reversed in all subject groups depending on where attention was oriented. These findings are consistent with our hypothesis of crossover: (1) crossover is a normal component of performance on line bisection; (2) crossover results from the interplay of biases in attentional orientation and magnitude estimation; and (3) attentional orientation predicts the direction of crossover, whereas a disorder of magnitude estimation, not previously emphasized in neglect, accounts for the quantitative changes in length estimation that make crossover more obvious in neglect subjects

  12. Biases in attentional orientation and magnitude estimation explain crossover: neglect is a disorder of both.

    PubMed

    Mennemeier, Mark; Pierce, Christopher A; Chatterjee, Anjan; Anderson, Britt; Jewell, George; Dowler, Rachael; Woods, Adam J; Glenn, Tannahill; Mark, Victor W

    2005-08-01

    Crossover refers to a pattern of performance on the line bisection test in which short lines are bisected on the side opposite the true center of long lines. Although most patients with spatial neglect demonstrate crossover, contemporary theories of neglect cannot explain it. In contrast, we show that blending the psychophysical construct of magnitude estimation with neglect theory not only explains crossover, but also addresses a quantitative feature of neglect that is independent of spatial deficits. We report a prospective validation study of the orientation/estimation hypothesis of crossover. Forty subjects (17 patients with and without neglect following unilateral brain injury and 23 normal controls) completed four experiments that examined crossover using line bisection, line bisection with cueing, and reproducing line lengths from both memory and a standard. Replicating earlier findings, all except one subject group exhibited crossover on the standard line bisection test, all groups showed a spontaneous preference to orient attention to one end of the lines, and all groups overestimated the length of short lines and underestimated long lines. Biases in attentional orientation and magnitude estimation are exaggerated in patients with neglect. The truly novel finding of this study occurred when, after removing the line from the bisection task, the direction of crossover was completely reversed in all subject groups depending on where attention was oriented. These findings are consistent with our hypothesis of crossover: (1) crossover is a normal component of performance on line bisection; (2) crossover results from the interplay of biases in attentional orientation and magnitude estimation; and (3) attentional orientation predicts the direction of crossover, whereas a disorder of magnitude estimation, not previously emphasized in neglect, accounts for the quantitative changes in length estimation that make crossover more obvious in neglect subjects

  13. Crossover from nucleation to spinodal decomposition in a condensing vapor.

    PubMed

    Wedekind, Jan; Chkonia, Guram; Wölk, Judith; Strey, Reinhard; Reguera, David

    2009-09-21

    The mechanism controlling the initial step of a phase transition has a tremendous influence on the emerging phase. We study the crossover from a purely nucleation-controlled transition toward spinodal decomposition in a condensing Lennard-Jones vapor using molecular dynamics simulations. We analyze both the kinetics and at the same time the thermodynamics by directly reconstructing the free energy of cluster formation. We estimate the location of the spinodal, which lies at much deeper supersaturations than expected. Moreover, the nucleation barriers we find differ only by a constant from the classical nucleation theory predictions and are in very good agreement with semiempirical scaling relations. In the regime from very small barriers to the spinodal, growth controls the rate of the transition but not its nature because the activation barrier has not yet vanished. Finally, we discuss in detail the influence of the chosen reaction coordinate on the interpretation of such simulation results.

  14. Berezinskii-Kosterlitz-Thouless crossover in a photonic lattice

    SciTech Connect

    Small, Eran; Pugatch, Rami; Silberberg, Yaron

    2011-01-15

    We show that a periodic two-dimensional (2D) photonic lattice with Kerr nonlinearity exhibits a Berezinskii-Kosterlitz-Thouless (BKT) crossover associated with a vortex-unbinding transition. We find that averaging over random initial conditions is equivalent to Boltzmann thermal averaging with the discrete nonlinear Schro{center_dot}{center_dot}dinger Hamiltonian. By controlling the initial randomness we can continuously vary the effective temperature. Since this Hamiltonian is in the 2D XY universality class, a BKT transition ensues. We verify this prediction using experimentally accessible observables and find good agreement between theory and simulations. This opens the possibility of experimental access to interesting phase transitions known in condensed matter using nonlinear optics.

  15. Charge crossover at the U(1)-Higgs phase transition

    SciTech Connect

    Freire, Filipe; Litim, Daniel F.

    2001-08-15

    The type-I region of phase transitions at finite temperature of the U(1)-Higgs theory in 3+1 dimensions is investigated in detail using a Wilsonian renormalization group. We consider, in particular, the quantitative effects induced through the crossover of the scale-dependent Abelian charge from the Gaussian to a nontrivial Abelian fixed point. As a result, the strength of the first-order phase transition is weakened. Analytical solutions to approximate flow equations are obtained, and all characteristics of the phase transition are discussed and compared to the results obtained from perturbation theory. In addition, we present a detailed quantitative study regarding the dependence of the physical observables on the coarse-graining scheme. This results in error bars for the regularization scheme (RS) dependence. We find quantitative evidence for an intimate link between the RS dependence and truncations of flow equations.

  16. Dimensionality crossover and frustrated spin dynamics on a triangular lattice

    NASA Astrophysics Data System (ADS)

    Wikberg, J. M.; Dahbi, M.; Saadoune, I.; Gustafsson, T.; Edström, K.; Svedlindh, P.

    2010-06-01

    Investigations of the magnetic behavior of the layered oxide, LiNi0.65Co0.25Mn0.10O2 , through ac and time-dependent susceptibility, dc linear and nonlinear susceptibility as well as neutron-diffraction measurements are presented. A ferrimagneticlike spin ordering appears at 119 K with a spontaneous magnetization coexisting with spin frustration in two dimensions (2D). At lower temperature, a cluster-glass transition is found at 17.4 K indicating a transformation to a completely frustrated state in three dimensions (3D). A dimensionality crossover with temperature, from 2D to 3D, in a magnetically frustrated system has been demonstrated. The observed magnetic behavior is believed to originate from a percolating system of spin clusters defined by disordered and frustrated exchange interactions and the findings conform well with predictions of the percolation cluster model.

  17. Quantum Corrections Crossover and Ferromagnetism in Magnetic Topological Insulators

    PubMed Central

    Bao, Lihong; Wang, Weiyi; Meyer, Nicholas; Liu, Yanwen; Zhang, Cheng; Wang, Kai; Ai, Ping; Xiu, Faxian

    2013-01-01

    Revelation of emerging exotic states of topological insulators (TIs) for future quantum computing applications relies on breaking time-reversal symmetry and opening a surface energy gap. Here, we report on the transport response of Bi2Te3 TI thin films in the presence of varying Cr dopants. By tracking the magnetoconductance (MC) in a low doping regime we observed a progressive crossover from weak antilocalization (WAL) to weak localization (WL) as the Cr concentration increases. In a high doping regime, however, increasing Cr concentration yields a monotonically enhanced anomalous Hall effect (AHE) accompanied by an increasing carrier density. Our results demonstrate a possibility of manipulating bulk ferromagnetism and quantum transport in magnetic TI, thus providing an alternative way for experimentally realizing exotic quantum states required by spintronic applications. PMID:23928713

  18. Crossover Phenomena in Detrended Fluctuation Analysis Used in Financial Markets

    NASA Astrophysics Data System (ADS)

    Ma, Shi-Hao

    2009-02-01

    A systematic analysis of Shanghai and Japan stock indices for the period of Jan. 1984 to Dec. 2005 is performed. After stationarity is verified by ADF (Augmented Dickey-Fuller) test, the power spectrum of the data exhibits a power law decay as a whole characterized by 1/fβ processes with possible long range correlations. Subsequently, by using the method of detrended fluctuation analysis (DFA) of the general volatility in the stock markets, we find that the long-range correlations are occurred among the return series and the crossover phenomena exhibit in the results obviously. Further, Shanghai stock market shows long-range correlations in short time scale and shows short-range correlations in long time scale. Whereas, for Japan stock market, the data behaves oppositely absolutely. Last, we compare the varying of scale exponent in large volatility between two stock markets. All results obtained may indicate the possibility of characteristic of multifractal scaling behavior of the financial markets.

  19. Metal ion sensing solution containing double crossover DNA

    NASA Astrophysics Data System (ADS)

    Park, Byeongho; Dugasani, Sreekantha R.; Cho, Youngho; Oh, Juyeong; Kim, Chulki; Seo, Min Ah; Lee, Taikjin; Jhon, Young Miin; Woo, Deok Ha; Lee, Seok; Jun, Seong Chan; Park, Sung Ha; Kim, Jae Hun

    2015-07-01

    The current study describes metal ion sensing with double crossover DNAs (DX1 and DX2), artificially designed as a platform of doping. The sample for sensing is prepared by a facile annealing method to grow the DXs lattice on a silicon/silicon oxide. Adding and incubating metal ion solution with the sensor substrate into the micro-tube lead the optical property change. Photoluminescence (PL) is employed for detecting the concentration of metal ion in the specimen. We investigated PL emission for sensor application with the divalent copper. In the range from 400 to 650 nm, the PL features of samples provide significantly different peak positions with excitation and emission detection. Metal ions contribute to modify the optical characteristics of DX with structural and functional change, which results from the intercalation of them into hydrogen bonding positioned at the center of double helix. The PL intensity is decreased gradually after doping copper ion in the DX tile on the substrate.

  20. Optimal adaptive sequential designs for crossover bioequivalence studies.

    PubMed

    Xu, Jialin; Audet, Charles; DiLiberti, Charles E; Hauck, Walter W; Montague, Timothy H; Parr, Alan F; Potvin, Diane; Schuirmann, Donald J

    2016-01-01

    In prior works, this group demonstrated the feasibility of valid adaptive sequential designs for crossover bioequivalence studies. In this paper, we extend the prior work to optimize adaptive sequential designs over a range of geometric mean test/reference ratios (GMRs) of 70-143% within each of two ranges of intra-subject coefficient of variation (10-30% and 30-55%). These designs also introduce a futility decision for stopping the study after the first stage if there is sufficiently low likelihood of meeting bioequivalence criteria if the second stage were completed, as well as an upper limit on total study size. The optimized designs exhibited substantially improved performance characteristics over our previous adaptive sequential designs. Even though the optimized designs avoided undue inflation of type I error and maintained power at ≥ 80%, their average sample sizes were similar to or less than those of conventional single stage designs.

  1. Crossover from adiabatic to antiadiabatic quantum pumping with dissipation.

    PubMed

    Pellegrini, Franco; Negri, C; Pistolesi, F; Manini, Nicola; Santoro, Giuseppe E; Tosatti, Erio

    2011-08-05

    Quantum pumping, in its different forms, is attracting attention from different fields, from fundamental quantum mechanics, to nanotechnology, to superconductivity. We investigate the crossover of quantum pumping from the adiabatic to the antiadiabatic regime in the presence of dissipation, and find general and explicit analytical expressions for the pumped current in a minimal model describing a system with the topology of a ring forced by a periodic modulation of frequency ω. The solution allows following in a transparent way the evolution of pumped dc current from much smaller to much larger ω values than the other relevant energy scale, the energy splitting introduced by the modulation. We find and characterize a temperature-dependent optimal value of the frequency for which the pumped current is maximal.

  2. Factors underlying restricted crossover localization in barley meiosis.

    PubMed

    Higgins, James D; Osman, Kim; Jones, Gareth H; Franklin, F Chris H

    2014-01-01

    Meiotic recombination results in the formation of cytological structures known as chiasmata at the sites of genetic crossovers (COs). The formation of at least one chiasma/CO between homologous chromosome pairs is essential for accurate chromosome segregation at the first meiotic division as well as for generating genetic variation. Although DNA double-strand breaks, which initiate recombination, are widely distributed along the chromosomes, this is not necessarily reflected in the chiasma distribution. In many species there is a tendency for chiasmata to be distributed in favored regions along the chromosomes, whereas in others, such as barley and some other grasses, chiasma localization is extremely pronounced. Localization of chiasma to the distal regions of barley chromosomes restricts the genetic variation available to breeders. Studies reviewed herein are beginning to provide an explanation for chiasma localization in barley. Moreover, they suggest a potential route to manipulating chiasma distribution that could be of value to plant breeders.

  3. Crossover behavior of conductivity in a discontinuous percolation model.

    PubMed

    Kim, Seongmin; Cho, Y S; Araújo, N A M; Kahng, B

    2014-03-01

    When conducting bonds are occupied randomly in a two-dimensional square lattice, the conductivity of the system increases continuously as the density of those conducting bonds exceeds the percolation threshold. Such a behavior is well known in percolation theory; however, the conductivity behavior has not been studied yet when the percolation transition is discontinuous. Here we investigate the conductivity behavior through a discontinuous percolation model evolving under a suppressive external bias. Using effective medium theory, we analytically calculate the conductivity behavior as a function of the density of conducting bonds. The conductivity function exhibits a crossover behavior from a drastically to a smoothly increasing function beyond the percolation threshold in the thermodynamic limit. The analytic expression fits well our simulation data.

  4. Crossover from BCS to Bose superconductivity: A functional integral approach

    SciTech Connect

    Randeria, M.; Sa de Melo, C.A.R.; Engelbrecht, J.R.

    1993-04-01

    We use a functional integral formulation to study the crossover from cooperative Cooper pairing to the formation and condensation of tightly bound pairs in a 3D continuum model of fermions with attractive interactions. The inadequacy of a saddle point approximation with increasing coupling is pointed out, and the importance of temporal (quantum) fluctuations for normal state properties at intermediate and strong coupling is emphasized. In addition to recovering the Nozieres-Schmitt-Pink interpolation scheme for T{sub c}, and the Leggett variational results for T = 0, we also present results for evolution of the time-dependent Ginzburg-Landau equation and collective mode spectrum as a function of the coupling.

  5. A crossover in anisotropic nanomechanochemistry of van der Waals crystals

    SciTech Connect

    Shimamura, Kohei; Misawa, Masaaki; Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya; Shimojo, Fuyuki

    2015-12-07

    In nanoscale mechanochemistry, mechanical forces selectively break covalent bonds to essentially control chemical reactions. An archetype is anisotropic detonation of layered energetic molecular crystals bonded by van der Waals (vdW) interactions. Here, quantum molecular dynamics simulations reveal a crossover of anisotropic nanomechanochemistry of vdW crystal. Within 10{sup −13} s from the passage of shock front, lateral collision produces NO{sub 2} via twisting and bending of nitro-groups and the resulting inverse Jahn-Teller effect, which is mediated by strong intra-layer hydrogen bonds. Subsequently, as we transition from heterogeneous to homogeneous mechanochemical regimes around 10{sup −12} s, shock normal to multilayers becomes more reactive, producing H{sub 2}O assisted by inter-layer N-N bond formation. These time-resolved results provide much needed atomistic understanding of nanomechanochemistry that underlies a wider range of technologies.

  6. Economic crossover parameters for outsourcing water treatment equipment

    SciTech Connect

    Sinha, K.; Khan, S.

    1998-12-31

    Outsourcing water treatment systems is an attractive alternative to installing permanent systems. The current industry trend favors leased and outsourced systems for demineralized water applications when water demands are small and no pretreatment system is required. This paper provides economic crossover parameters for power plant applications, taking life cycle costs into consideration, including operation and maintenance (O and M) and capital costs, auxiliary load and heat rate penalties, O and M personnel requirements, and other economic considerations. Furthermore, the paper establishes ground rules for such comparisons between outsourced and permanent water treatment systems considering demineralization of water as well as impact on other power plant systems. Water production costs and $/1,000 gallon cost parameters for water production are presented, with graphical references to the economic parameters discussed.

  7. A luminescent Pt2Fe spin crossover complex.

    PubMed

    Schäfer, Bernhard; Bauer, Thomas; Faus, Isabelle; Wolny, Juliusz A; Dahms, Fabian; Fuhr, Olaf; Lebedkin, Sergei; Wille, Hans-Christian; Schlage, Kai; Chevalier, Katharina; Rupp, Fabian; Diller, Rolf; Schünemann, Volker; Kappes, Manfred M; Ruben, Mario

    2017-02-14

    A heterotrinuclear [Pt2Fe] spin crossover (SCO) complex was developed and synthesized employing a ditopic bridging bpp-alkynyl ligand L and alkynyl coordinated Pt(II) terpy units: [Fe(II)(L-Pt(II))2]2(BF4)2 (1). We identified two different types of crystals of 1 which differ in their molecular packing and the number of co-crystallized solvent molecules: 1H (1·3.5CH2Cl2 in P1[combining macron]) and 1L (1·10CH2Cl2 in C2/c); while 1L shows a reversible SCO with a transition temperature of 268 K, the analogous compound 1H does not show any SCO and remains blocked in the HS state. The temperature-dependent magnetic properties of 1H and 1L were complementarily studied by Mössbauer spectroscopy. It has been shown that 1L performs thermal spin crossover and that 1L can be excited to a LIESST state. The vibrational properties of 1 were investigated by experimental nuclear resonance vibrational spectroscopy. The experimentally determined partial density of vibrational states (pDOS) was compared to a DFT-based simulation of the pDOS. The vibrational modes of the different components were assigned and visualized. In addition, the photophysical properties of 1 and L-Pt were investigated in the solid state and in solution. The ultrafast transient absorption spectroscopy of 1 in solution was carried out to study the PL quenching channel via energy transfer from photoexcited Pt(II) terpy units to the Fe(II)-moiety.

  8. Design and numerical characterization of a crossover EBIS

    NASA Astrophysics Data System (ADS)

    Geyer, Sabrina; Langbein, A.; Meusel, Oliver; Kester, Oliver

    2015-01-01

    For the investigation of highly charged ions, a crossover EBIS (XEBIS) was developed at the University of Frankfurt. In contrast to conventional EBIS/T devices the compression of the electron beam is achieved by electrostatic focusing to a crossover point in the interaction region. This concept allows a compact and simple design. Simulations performed with EGUN show a perveance of 2.1×10-7 A/V3/2 for the realized gun system. In the interaction region the electron beam has a density of around 10 A/cm2 and a minimum radius of 0.15 mm. The XEBIS has a total length of 112 mm with a trap length of 26 mm. It is designed for electron beam energies of up to 6 keV/q. The storage capacity of the trap region is in the order of 1×108 charges. Charge state breeding studies with CBSIM indicate for the noble gases as maximal achievable charge state Ar16+, Kr30+ and Xe35+. Thus ion beam currents of around 2.04 nA assuming 50 Hz repetition rate can be expected. The emittance of the extracted beam is approximated to 8 mm mrad. After completion of the construction phase, the XEBIS will be installed for first performance investigations at a dedicated test bench, equipped with a fast Faraday Cup (FC), a retarding field spectrometer, a luminescence screen and optical diagnostics. Subsequently the XEBIS will serve as source for highly charged ions at different experimental setups.

  9. Design and numerical characterization of a crossover EBIS

    SciTech Connect

    Geyer, Sabrina Langbein, A. Meusel, Oliver; Kester, Oliver

    2015-01-09

    For the investigation of highly charged ions, a crossover EBIS (XEBIS) was developed at the University of Frankfurt. In contrast to conventional EBIS/T devices the compression of the electron beam is achieved by electrostatic focusing to a crossover point in the interaction region. This concept allows a compact and simple design. Simulations performed with EGUN show a perveance of 2.1×10{sup −7} A/V{sup 3/2} for the realized gun system. In the interaction region the electron beam has a density of around 10 A/cm{sup 2} and a minimum radius of 0.15 mm. The XEBIS has a total length of 112 mm with a trap length of 26 mm. It is designed for electron beam energies of up to 6 keV/q. The storage capacity of the trap region is in the order of 1×10{sup 8} charges. Charge state breeding studies with CBSIM indicate for the noble gases as maximal achievable charge state Ar{sup 16+}, Kr{sup 30+} and Xe{sup 35+}. Thus ion beam currents of around 2.04 nA assuming 50 Hz repetition rate can be expected. The emittance of the extracted beam is approximated to 8 mm mrad. After completion of the construction phase, the XEBIS will be installed for first performance investigations at a dedicated test bench, equipped with a fast Faraday Cup (FC), a retarding field spectrometer, a luminescence screen and optical diagnostics. Subsequently the XEBIS will serve as source for highly charged ions at different experimental setups.

  10. Bacterial colony counting by Convolutional Neural Networks.

    PubMed

    Ferrari, Alessandro; Lombardi, Stefano; Signoroni, Alberto

    2015-01-01

    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.

  11. B Counting at BaBar

    SciTech Connect

    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%.

  12. Direct Validation of the Wall Interference Correction System of the Ames 11-Foot Transonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Ulbrich, Norbert; Boone, Alan R.

    2003-01-01

    Data from the test of a large semispan model was used to perform a direct validation of a wall interference correction system for a transonic slotted wall wind tunnel. At first, different sets of uncorrected aerodynamic coefficients were generated by physically changing the boundary condition of the test section walls. Then, wall interference corrections were computed and applied to all data points. Finally, an interpolation of the corrected aerodynamic coefficients was performed. This interpolation made sure that the corrected Mach number of a given run would be constant. Overall, the agreement between corresponding interpolated lift, drag, and pitching moment coefficient sets was very good. Buoyancy corrections were also investigated. These studies showed that the accuracy goal of one drag count may only be achieved if reliable estimates of the wall interference induced buoyancy correction are available during a test.

  13. Ramsey Interference with Single Photons

    NASA Astrophysics Data System (ADS)

    Clemmen, Stéphane; Farsi, Alessandro; Ramelow, Sven; Gaeta, Alexander L.

    2016-11-01

    Interferometry using discrete energy levels of nuclear, atomic, or molecular systems is the foundation for a wide range of physical phenomena and enables powerful techniques such as nuclear magnetic resonance, electron spin resonance, Ramsey-based spectroscopy, and laser or maser technology. It also plays a unique role in quantum information processing as qubits may be implemented as energy superposition states of simple quantum systems. Here, we demonstrate quantum interference involving energy states of single quanta of light. In full analogy to the energy levels of atoms or nuclear spins, we implement a Ramsey interferometer with single photons. We experimentally generate energy superposition states of a single photon and manipulate them with unitary transformations to realize arbitrary projective measurements. Our approach opens the path for frequency-encoded photonic qubits in quantum information processing and quantum communication.

  14. Spatial light interference tomography (SLIT)

    PubMed Central

    Wang, Zhuo; Marks, Daniel L.; Carney, Paul Scott; Millet, Larry J.; Gillette, Martha U.; Mihi, Agustin; Braun, Paul V.; Shen, Zhen; Prasanth, Supriya G.; Popescu, Gabriel

    2011-01-01

    We present spatial light interference tomography (SLIT), a label-free method for 3D imaging of transparent structures such as live cells. SLIT uses the principle of interferometric imaging with broadband fields and combines the optical gating due to the micron-scale coherence length with that of the high numerical aperture objective lens. Measuring the phase shift map associated with the object as it is translated through focus provides full information about the 3D distribution associated with the refractive index. Using a reconstruction algorithm based on the Born approximation, we show that the sample structure may be recovered via a 3D, complex field deconvolution. We illustrate the method with reconstructed tomographic refractive index distributions of microspheres, photonic crystals, and unstained living cells. PMID:21996999

  15. Age determination in manatees using growth-layer-group counts in bone

    USGS Publications Warehouse

    Marmontel, M.; O'Shea, T.J.; Kochman, H.I.; Humphrey, S.R.

    1996-01-01

    Growth layers were observed in histological preparations of bones of known-age, known minimum-age, and tetracycline-marked free-ranging and captive Florida manatees (Trichechus manatus latirostris), substantiating earlier preliminary findings of other studies. Detailed analysis of 17 new case histories showed that growth-layer group (GLG) counts in the periotic bone were consistent with known age, or time since tetracycline administration, but were less reliable in other bones. GLG counts were also made in periotic bones of 1,196 Florida manatees of unknown age found dead from 1974 through 1991. These counts were conducted in order to assess variability and to determine relationships among estimated age, size, sex, and degree of bone resorption. Resorption can interfere with accuracy of GLG counts. This effect does not occur until ages greater than about 15 yr and body lengths greater than 300 cm are attained. GLGs were also observed in periotic bones of Antillean manatees (Trichechus manatus manatus) but were not validated against known-age specimens. Use of GLG counts in the periotic bone is suitable for application to studies of population dynamics and other age-related aspects of manatee biology.

  16. Investigation of interference in multiple-input multiple-output wireless transmission at W band for an optical wireless integration system.

    PubMed

    Li, Xinying; Yu, Jianjun; Dong, Ze; Zhang, Junwen; Chi, Nan; Yu, Jianguo

    2013-03-01

    We experimentally investigate the interference in multiple-input multiple-output (MIMO) wireless transmission by adjusting the relative locations of horn antennas (HAs) in a 100 GHz optical wireless integration system, which can deliver a 50 Gb/s polarization-division-multiplexing quadrature-phase-shift-keying signal over 80 km single-mode fiber-28 and a 2×2 MIMO wireless link. For the parallel 2×2 MIMO wireless link, each receiver HA can only get wireless power from the corresponding transmitter HA, while for the crossover ones, the receiver HA can get wireless power from two transmitter HAs. At the wireless receiver, polarization demultiplexing is realized by the constant modulus algorithm (CMA) in the digital-signal-processing part. Compared to the parallel case, wireless interference causes about 2 dB optical signal-to-noise ratio penalty at a bit-error ratio (BER) of 3.8×10(-3) for the crossover cases if similar CMA taps are employed. The increase in CMA tap length can reduce wireless interference and improve BER performance. Furthermore, more CMA taps should be adopted to overcome the severe wireless interference when two pairs of transmitter and receiver HAs have different wireless distances.

  17. Calorie count - sodas and energy drinks

    MedlinePlus

    ... ency/patientinstructions/000888.htm Calorie count - sodas and energy drinks To use the sharing features on this ... to have a few servings of soda or energy drinks a day without thinking about it. Like ...

  18. 7 CFR 1280.628 - Counting ballots.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE LAMB PROMOTION, RESEARCH, AND..., the requests shall be counted no later than the 14th business day following the final day of...

  19. Pneumotachometer counts respiration rate of human subject

    NASA Technical Reports Server (NTRS)

    Graham, O.

    1964-01-01

    To monitor breaths per minute, two rate-to-analog converters are alternately used to read and count the respiratory rate from an impedance pneumograph sequentially displayed numerically on electroluminescent matrices.

  20. The perirhinal cortex and recognition memory interference

    PubMed Central

    Watson, H.C.; Lee, A. C. H.

    2013-01-01

    There has recently been an increase in interest in the effects of visual interference on memory processing, with the aim of eluciating the role of the perirhinal cortex (PRC) in recognition memory. One view argues that the PRC processes highly complex conjunctions of object features, and recent evidence from rodents suggests that these representations may be vital for buffering against the effects of pre-retrieval interference on object recognition memory. To investigate whether PRC-dependent object representations play a similar role in humans, we used functional magnetic resonance imaging to scan neurologically healthy participants while they carried out a novel interference-match-to-sample task. This paradigm was specifically designed to concurrently assess the impact of object vs. spatial interference, on recognition memory for objects or scenes, while keeping constant the amount of object and scene information presented across all trials. Activity at retrieval was examined, within an anatomically defined PRC region of interest, according to the demand for object or scene memory, following a period of object compared to spatial interference. Critically, we found greater PRC activity for object memory following object interference, compared to object memory following scene interference, and no difference between object and scene interference for scene recognition. These data demonstrate a role for the human PRC following a period of object, but not scene, interference, during object recognition memory, and emphasize the importance of representational content to mnemonic processing. PMID:23447626

  1. The perirhinal cortex and recognition memory interference.

    PubMed

    Watson, Hilary C; Lee, Andy C H

    2013-02-27

    There has recently been an increase in interest in the effects of visual interference on memory processing, with the aim of elucidating the role of the perirhinal cortex (PRC) in recognition memory. One view argues that the PRC processes highly complex conjunctions of object features, and recent evidence from rodents suggests that these representations may be vital for buffering against the effects of pre-retrieval interference on object recognition memory. To investigate whether PRC-dependent object representations play a similar role in humans, we used functional magnetic resonance imaging to scan neurologically healthy participants while they performed a novel interference-match-to-sample task. This paradigm was specifically designed to concurrently assess the impact of object versus spatial interference, on recognition memory for objects or scenes, while keeping constant the amount of object and scene information presented across all trials. Activity at retrieval was examined, within an anatomically defined PRC region of interest, according to the demand for object or scene memory, following a period of object compared with spatial interference. Critically, we found greater PRC activity for object memory following object interference, compared with object memory following scene interference, and no difference between object and scene interference for scene recognition. These data demonstrate a role for the human PRC during object recognition memory, following a period of object, but not scene interference, and emphasize the importance of representational content to mnemonic processing.

  2. Quantum interference of edge supercurrents in a two-dimensional topological insulator

    NASA Astrophysics Data System (ADS)

    Tkachov, Grigory; Burset, Pablo; Trauzettel, Bjoern; Hankiewicz, Ewelina

    2015-03-01

    Josephson weak links made of two-dimensional topological insulators (TIs) exhibit magnetic oscillations of the supercurrent that are reminiscent of those in superconducting quantum interference devices. We propose a microscopic theory of such a TI SQUID effect. The key ingredient of our model is the exact treatment of the influence of an external magnetic field on the edge supercurrents. We show that this influence has the form of a 1D Doppler effect that describes the flux-controlled interference of the edge currents with superimposed suppression of Andreev reflection. Both long and short junctions are discussed. In particular, for long junctions the theory shows a temperature-driven crossover from the normal Φ0-periodic SQUID pattern to a 2 Φ0- quasiperiodic pattern consisting of a series of alternating even and odd peaks (where Φ0=ch/2e is the magnetic flux quantum). The predicted even-odd effect is the signature of gapless (protected) Andreev bound states with a sawtooth dependence on the magnetic flux. Our findings may shed some light on the recently observed even-odd interference pattern in InAs/GaSb-based TI Josephson junctions, suggesting new operation regimes for nano-SQUIDs. G.T. acknowledges financial support of the German Research Foundation (DFG Grant No TK60/1-1). This work was also supported by DFG FOR 1162, SPP1666, JST research unit ``Topotronics'' and the ENB graduate school ``Topological insulators.''

  3. Statistical modelling for falls count data.

    PubMed

    Ullah, Shahid; Finch, Caroline F; Day, Lesley

    2010-03-01

    Falls and their injury outcomes have count distributions that are highly skewed toward the right with clumping at zero, posing analytical challenges. Different modelling approaches have been used in the published literature to describe falls count distributions, often without consideration of the underlying statistical and modelling assumptions. This paper compares the use of modified Poisson and negative binomial (NB) models as alternatives to Poisson (P) regression, for the analysis of fall outcome counts. Four different count-based regression models (P, NB, zero-inflated Poisson (ZIP), zero-inflated negative binomial (ZINB)) were each individually fitted to four separate fall count datasets from Australia, New Zealand and United States. The finite mixtures of P and NB regression models were also compared to the standard NB model. Both analytical (F, Vuong and bootstrap tests) and graphical approaches were used to select and compare models. Simulation studies assessed the size and power of each model fit. This study confirms that falls count distributions are over-dispersed, but not dispersed due to excess zero counts or heterogeneous population. Accordingly, the P model generally provided the poorest fit to all datasets. The fit improved significantly with NB and both zero-inflated models. The fit was also improved with the NB model, compared to finite mixtures of both P and NB regression models. Although there was little difference in fit between NB and ZINB models, in the interests of parsimony it is recommended that future studies involving modelling of falls count data routinely use the NB models in preference to the P or ZINB or finite mixture distribution. The fact that these conclusions apply across four separate datasets from four different samples of older people participating in studies of different methodology, adds strength to this general guiding principle.

  4. Minimum Disclosure Counting for the Alternative Vote

    NASA Astrophysics Data System (ADS)

    Wen, Roland; Buckland, Richard

    Although there is a substantial body of work on preventing bribery and coercion of voters in cryptographic election schemes for plurality electoral systems, there are few attempts to construct such schemes for preferential electoral systems. The problem is preferential systems are prone to bribery and coercion via subtle signature attacks during the counting. We introduce a minimum disclosure counting scheme for the alternative vote preferential system. Minimum disclosure provides protection from signature attacks by revealing only the winning candidate.

  5. Preverbal and verbal counting and computation.

    PubMed

    Gallistel, C R; Gelman, R

    1992-08-01

    We describe the preverbal system of counting and arithmetic reasoning revealed by experiments on numerical representations in animals. In this system, numerosities are represented by magnitudes, which are rapidly but inaccurately generated by the Meck and Church (1983) preverbal counting mechanism. We suggest the following. (1) The preverbal counting mechanism is the source of the implicit principles that guide the acquisition of verbal counting. (2) The preverbal system of arithmetic computation provides the framework for the assimilation of the verbal system. (3) Learning to count involves, in part, learning a mapping from the preverbal numerical magnitudes to the verbal and written number symbols and the inverse mappings from these symbols to the preverbal magnitudes. (4) Subitizing is the use of the preverbal counting process and the mapping from the resulting magnitudes to number words in order to generate rapidly the number words for small numerosities. (5) The retrieval of the number facts, which plays a central role in verbal computation, is mediated via the inverse mappings from verbal and written numbers to the preverbal magnitudes and the use of these magnitudes to find the appropriate cells in tabular arrangements of the answers. (6) This model of the fact retrieval process accounts for the salient features of the reaction time differences and error patterns revealed by experiments on mental arithmetic. (7) The application of verbal and written computational algorithms goes on in parallel with, and is to some extent guided by, preverbal computations, both in the child and in the adult.

  6. Using RNA interference to identify genes required for RNA interference

    PubMed Central

    Dudley, Nathaniel R.; Labbé, Jean-Claude; Goldstein, Bob

    2002-01-01

    RNA interference (RNAi) is a phenomenon in which double-stranded RNA (dsRNA) silences endogenous gene expression. By injecting pools of dsRNAs into Caenorhabditis elegans, we identified a dsRNA that acts as a potent suppressor of the RNAi mechanism. We have used coinjection of dsRNAs to identify four additional candidates for genes involved in the RNAi mechanism in C. elegans. Three of the genes are C. elegans mes genes, some of which encode homologs of the Drosophila chromatin-binding Polycomb-group proteins. We have used loss-of-function mutants to confirm a role for mes-3, -4, and -6 in RNAi. Interestingly, introducing very low levels of dsRNA can bypass a requirement for these genes in RNAi. The finding that genes predicted to encode proteins that associate with chromatin are involved in RNAi in C. elegans raises the possibility that chromatin may play a role in RNAi in animals, as it does in plants. PMID:11904378

  7. Cosmic ray neutron background reduction using localized coincidence veto neutron counting

    DOEpatents

    Menlove, Howard O.; Bourret, Steven C.; Krick, Merlyn S.

    2002-01-01

    This invention relates to both the apparatus and method for increasing the sensitivity of measuring the amount of radioactive material in waste by reducing the interference caused by cosmic ray generated neutrons. The apparatus includes: (a) a plurality of neutron detectors, each of the detectors including means for generating a pulse in response to the detection of a neutron; and (b) means, coupled to each of the neutrons detectors, for counting only some of the pulses from each of the detectors, whether cosmic ray or fission generated. The means for counting includes a means that, after counting one of the pulses, vetos the counting of additional pulses for a prescribed period of time. The prescribed period of time is between 50 and 200 .mu.s. In the preferred embodiment the prescribed period of time is 128 .mu.s. The veto means can be an electronic circuit which includes a leading edge pulse generator which passes a pulse but blocks any subsequent pulse for a period of between 50 and 200 .mu.s. Alternately, the veto means is a software program which includes means for tagging each of the pulses from each of the detectors for both time and position, means for counting one of the pulses from a particular position, and means for rejecting those of the pulses which originate from the particular position and in a time interval on the order of the neutron die-away time in polyethylene or other shield material. The neutron detectors are grouped in pods, preferably at least 10. The apparatus also includes means for vetoing the counting of coincidence pulses from all of the detectors included in each of the pods which are adjacent to the pod which includes the detector which produced the pulse which was counted.

  8. Effect of gas composition on Ru dissolution and crossover in polymer-electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Cheng, Tommy T. H.; Jia, Nengyou; Colbow, Vesna; Wessel, Silvia; Dutta, Monica

    Pt-Ru-based anodes are commonly used in polymer-electrolyte membrane fuel cells (PEMFCs) to provide improved CO tolerance for reformate fuel applications. However, Ru crossover from the anode to the cathode has been identified as a critical durability problem that has severe performance implications. In the present study, an anode accelerated stress test (AST) was used to simulate potential spikes that occur during fuel cell start-ups and shutdowns to induce Ru crossover. The effects of fuel gas composition, namely hydrogen and carbon dioxide concentrations, on Ru dissolution and crossover were investigated. The cell performance losses were correlated with the degree of Ru crossover as determined by the changes in cathode cyclic voltammetry (CV) characteristics and neutron activation analysis (NAA). It was found that higher hydrogen concentration in the fuel accelerated Ru crossover and that the presence of carbon dioxide hindered Ru crossover. In particular, the injection of 20 vol.% carbon dioxide during potential cycling resulted in very minor Ru crossover, which showed essentially identical performance losses and CV characteristic changes as a fuel cell composed of a Ru-free anode. The experimental results suggest that the Ru species in our Pt-Ru metal oxide catalysts need to go through a reduction step by hydrogen before dissolution. The presence of carbon dioxide may play a role in hindering the reduction step.

  9. Temporal coherence and indistinguishability in two-photon interference effects

    SciTech Connect

    Jha, Anand Kumar; O'Sullivan, Malcolm N.; Chan, Kam Wai Clifford; Boyd, Robert W.

    2008-02-15

    We show that temporal two-photon interference effects involving the signal and idler photons created by parametric down-conversion can be fully characterized in terms of the variations of two length parameters--called the biphoton path-length difference and the biphoton path-asymmetry-length difference--which we construct using the six different length parameters that a general two-photon interference experiment involves. We perform an experiment in which the effects of the variations of these two parameters can be independently controlled and studied. In our experimental setup, which does not involve mixing of signal and idler photons at a beam splitter, we further report observations of Hong-Ou-Mandel- (HOM-)like effects both in coincidence and in one-photon count rates. As an important consequence, we argue that the HOM and the HOM-like effects are best described as observations of how two-photon coherence changes as a function of the biphoton path-asymmetry-length difference.

  10. A Pilot Study on Culottes versus Crossover Single Stenting for True Coronary Bifurcation Lesions

    PubMed Central

    Zhang, Linlin; Zhong, Wenliang; Luo, Yukun; Chen, Lianglong

    2016-01-01

    Background The purpose of our study was to compare clinical and angiographic outcomes of planned culottes technique with that of provisional crossover single stenting in the treatment of true coronary bifurcation lesions (CBL) with drug-eluting stent (DES). Methods True CBL patients (n = 104) were randomly assigned to either the provisional stenting of the side branch (crossover group) or the culottes group. Additional side branch (SB) stenting in the crossover group was required if there was thrombolysis in myocardial infarction flow ≤ 1 flow). The primary end point was the occurrence of major adverse cardiac events (MACE) at nine months, including cardiac death, myocardial infarction, target lesion/vessel revascularization and in-stent thrombosis. The secondary end point was angiographic in-segment restenosis at nine months. Results The rate of MACE at nine months was similar between the crossover and culottes groups (7.7% vs. 7.7%, p = 1.000). Additional SB stenting in the crossover group was required in 3.8% of patients. There was one procedural occlusion of SB in the crossover group. At nine months, the rate of in-segment restenosis was similar in the parent main vessel (0% vs. 1.9%, p = 1.000), main branch (1.9% vs. 7.7%, p = 0.363) and SB (17.3% vs. 9.6%, p = 0.250) between the crossover and culottes groups, respectively. Conclusions This study demonstrated that there is no significant difference in cumulative MACE or in-segment restenosis between crossover and culottes groups. Larger randomized clinical trials are warranted to re-evaluate the outcomes of the provisional crossover stenting versus the culottes stenting techniques utilizing DES for true CBL. PMID:27471358

  11. Multiray interference in a segment of fiber optic communication line

    NASA Astrophysics Data System (ADS)

    Sultanov, Albert H.; Vinogradova, Irina L.

    2001-10-01

    The influence of multiray interference on a propagation pulsed signal in fiber-optic communication line (FOCL) is considered. The multiray interference appears for each place, where the defect on optical factor of refraction occurs. The problem of distortion pulsed signal becomes particularly actual with development high speed calculate optical networks, which have a high degree an structure, and appearance of transmit technology of information with a spectral compaction. This is explained increasing amount of components in a transmit tract. Such optical processes are like the processes, appearing in multiray Fabry-Perot interferometer (FPI). In approach to a propagation light wave is close to flat, the model of a segment FOCL is built on the base of an independent FPI elements composition. Such model has allowed to make the quantitative estimation of interference multiplicated hindrance parameters by means statistical description of many elements FPI in FOCL system. The studies have shown, that for reflect index from butt-end of fiber within 3...5% the typical peaks of intensity during increasing of a signal pulse front are appeared. This case the count threshold in a decisive device for pulse with garbled fronts is reached in other moment of time to not-garbled fronts. The time delay result in a phase delay between consequences of pulses, which increase the probability of reading errors the bits. For active components FOCL situation is danger, when all or part of interferometers leave maximum their own transmission and the reflected wave will appear. The estimation of its amplitude is carried out, the correlation function and the spectrum of many elements FPI in FOCL hindrances are putted.

  12. Crossover replantation as a salvage procedure following bilateral transhumeral upper limb amputation: a case report.

    PubMed

    Ozçelik, Ismail Bülent; Mersa, Berkan; Kabakaş, Fatih; Saçak, Bülent; Kuvat, Samet Vasfi

    2011-04-01

    Cross-over replantation is a salvage option for cases with bilateral extremity amputations where the wound conditions do not enable an orthotopic replantation. Here, we present a 24-year-old patient who applied to our center with bilateral transhumeral amputations. Due to the wound conditions, a cross-over replantation was performed. 24 months after the initial operation, the patient exhibits good protective sensation at the distal levels and function to some degree, whereas the active range of motion is not as promising as previously expected. In this article, we present this case together with its immediate and long-term outcomes and the consequences of the cross-over replantation.

  13. Crossover versus parallel designs: dose-escalation design comparisons for first-in-human studies.

    PubMed

    Yan, Zhiwu; Hosmane, Balakrishna; Locke, Charles

    2013-01-01

    We study the statistical efficiency for rising-dose designs in the context of first-in-human studies. Specifically, we identify a class of crossover designs that are appealing in terms of both subject safety and statistical efficiency and, for a three-period, two-panel design in such a class, we compare its A-efficiency relative to the corresponding parallel designs and optimal/efficient crossover designs, respectively, under various plausible models. In the meantime, we also evaluate the impact of inclusion of baseline measurements as a covariate in the statistical analysis, for both crossover and parallel studies.

  14. 47 CFR 74.604 - Interference avoidance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Stations § 74.604 Interference avoidance. (a) (b) Where two or more licensees are assigned a common channel..., including time sharing arrangements, to assure an equitable distribution of available frequencies. (c) For those interference disputes brought to the Commission for resolution, TV broadcast auxiliary...

  15. The Contextual Interference Effect in Applied Settings

    ERIC Educational Resources Information Center

    Barreiros, Joao; Figueiredo, Teresa; Godinho, Mario

    2007-01-01

    This paper analyses the research literature that approaches the contextual interference effect in applied settings. In contrast to the laboratory settings, in which high interference conditions depress acquisition and promote learning evaluated in retention and transfer tests, in applied settings most of the studies (60%) fail to observe positive…

  16. Is There Semantic Interference in Delayed Naming?

    ERIC Educational Resources Information Center

    Madebach, Andreas; Oppermann, Frank; Hantsch, Ansgar; Curda, Christian; Jescheniak, Jorg D.

    2011-01-01

    The semantic interference effect in the picture-word interference task is interpreted as an index of lexical competition in prominent speech production models. Janssen, Schirm, Mahon, and Caramazza (2008) challenged this interpretation on the basis of experiments with a novel version of this task, which introduced a task-switching component.…

  17. Synthesis of an algorithm for interference immunity

    NASA Astrophysics Data System (ADS)

    Kartsan, I. N.; Tyapkin, V. N.; Dmitriev, D. D.; Goncharov, A. E.; Zelenkov, P. V.; Kovalev, I. V.

    2016-11-01

    This paper discusses the synthesis of an algorithm for adaptive interference nulling of an 8-element phased antenna array. An adaptive beamforming system has been built on the basis of the algorithm. The paper discusses results of experimental functioning of navigation satellite systems user equipment fitted with an adaptive phased antenna array in interference environments.

  18. Interference and the Law of Energy Conservation

    ERIC Educational Resources Information Center

    Drosd, Robert; Minkin, Leonid; Shapovalov, Alexander S.

    2014-01-01

    Introductory physics textbooks consider interference to be a process of redistribution of energy from the wave sources in the surrounding space resulting in constructive and destructive interferences. As one can expect, the total energy flux is conserved. However, one case of apparent non-conservation energy attracts great attention. Imagine that…

  19. 47 CFR 90.511 - Interference.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Interference. 90.511 Section 90.511 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Developmental Operation § 90.511 Interference. The operation of any station...

  20. 47 CFR 90.511 - Interference.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Interference. 90.511 Section 90.511 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Developmental Operation § 90.511 Interference. The operation of any station...

  1. 47 CFR 90.511 - Interference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Interference. 90.511 Section 90.511 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES PRIVATE LAND MOBILE RADIO SERVICES Developmental Operation § 90.511 Interference. The operation of any station...

  2. Optimal interference code based on machine learning

    NASA Astrophysics Data System (ADS)

    Qian, Ye; Chen, Qian; Hu, Xiaobo; Cao, Ercong; Qian, Weixian; Gu, Guohua

    2016-10-01

    In this paper, we analyze the characteristics of pseudo-random code, by the case of m sequence. Depending on the description of coding theory, we introduce the jamming methods. We simulate the interference effect or probability model by the means of MATLAB to consolidate. In accordance with the length of decoding time the adversary spends, we find out the optimal formula and optimal coefficients based on machine learning, then we get the new optimal interference code. First, when it comes to the phase of recognition, this study judges the effect of interference by the way of simulating the length of time over the decoding period of laser seeker. Then, we use laser active deception jamming simulate interference process in the tracking phase in the next block. In this study we choose the method of laser active deception jamming. In order to improve the performance of the interference, this paper simulates the model by MATLAB software. We find out the least number of pulse intervals which must be received, then we can make the conclusion that the precise interval number of the laser pointer for m sequence encoding. In order to find the shortest space, we make the choice of the greatest common divisor method. Then, combining with the coding regularity that has been found before, we restore pulse interval of pseudo-random code, which has been already received. Finally, we can control the time period of laser interference, get the optimal interference code, and also increase the probability of interference as well.

  3. Spin Interference in Rashba 2DEG Systems

    NASA Astrophysics Data System (ADS)

    Nitta, Junsaku

    The gate controllable SOI provides useful information about spin interference.1 Spin interference effects are studied in two different interference loop structures. It is known that sample specific conductance fluctuations affect the conductance in the interference loop. By using array of many interference loops, we carefully pick up TRS Altshuler-Aronov-Spivak (AAS)-type oscillation which is not sample specific and depends on the spin phase. The experimentally obtained gate voltage dependence of AAS oscillations indicates that the spin precession angle can be controlled by the gate voltage.2 We demonstrate the time reversal Aharonov-Casher (AC) effect in small arrays of mesoscopic rings.3 By using an electrostatic gate we can control the spin precession angle rate and follow the AC phase over several interference periods. We also see the second harmonic of the AC interference, oscillating with half the period. The spin interference is still visible after more than 20π precession angle. We have proposed a Stern-Gerlach type spin filter based on the Rashba SOI.4 A spatial gradient of effective magnetic field due to the nonuniform SOI separates spin up and down electrons. This spin filter works even without any external magnetic fields and ferromagnetic contacts. We show the semiconductor/ferromagnet hybrid structure is an effective way to detect magnetization process of submicron magnets. The problem of the spin injection from ferromagnetic contact into 2DEG is also disicussed. Note from Publisher: This article contains the abstract only.

  4. 7 CFR 51.564 - Requirements as to count.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... STANDARDS) United States Standards for Celery Count § 51.564 Requirements as to count. (a) The number of stalks of celery in the container may be specified by numerical count or in terms of dozens or...

  5. 7 CFR 51.564 - Requirements as to count.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... STANDARDS) United States Standards for Celery Count § 51.564 Requirements as to count. (a) The number of stalks of celery in the container may be specified by numerical count or in terms of dozens or...

  6. 7 CFR 51.564 - Requirements as to count.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... STANDARDS) United States Standards for Celery Count § 51.564 Requirements as to count. (a) The number of stalks of celery in the container may be specified by numerical count or in terms of dozens or...

  7. 7 CFR 51.564 - Requirements as to count.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Celery Count § 51.564 Requirements as to count. (a) The number of stalks of celery in the container may be specified by numerical count...

  8. 7 CFR 51.564 - Requirements as to count.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Celery Count § 51.564 Requirements as to count. (a) The number of stalks of celery in the container may be specified by numerical count...

  9. Effect of pedometer use and goal setting on walking and functional status in overweight adults with multimorbidity: a crossover clinical trial

    PubMed Central

    Takahashi, Paul Y; Quigg, Stephanie M; Croghan, Ivana T; Schroeder, Darrell R; Ebbert, Jon O

    2016-01-01

    Background Walking can improve functional status, and a pedometer and goal setting can increase walking and, potentially, gait speed. The efficacy of pedometer use and goal setting for increasing step counts among overweight and obese adults with multiple comorbid conditions has not been evaluated. Methods We recruited and randomly assigned obese or overweight adults with multimorbidity to immediate pedometer use with goal setting or delayed pedometer use, using a crossover design. The primary outcome of interest was step count, with secondary outcomes of gait speed and grip strength, with comparison between the intervention and delayed pedometer groups. Results Mean (standard deviation [SD]) age of the 130 participants was 63.4 (15.0) years. At 2 months, mean (SD) steps for the immediate pedometer use group (n=64) was 5,337 (3,096), compared with 4,446 (2,422) steps in the delayed pedometer group (n=66) (P=0.08). Within-group step count increased nonsignificantly, by 179 steps in the immediate pedometer group and 212 steps in the delayed pedometer group after 2 months of intervention, with no significant difference between the groups. Gait speed significantly increased by 0.08 m/s (P<0.05) and grip strength significantly increased by 1.6 kg (P<0.05) in the immediate pedometer group. Conclusion Pedometer use and goal setting did not significantly increase step count among overweight and obese adults with multimorbidity. The absolute step count was lower than many reported averages. Gait speed and grip strength increased with immediate pedometer use. The use of pedometers and goal setting may have an attenuated response in this population. PMID:27621602

  10. Exposures from headset interference tones

    NASA Astrophysics Data System (ADS)

    May, Noal D.

    1992-01-01

    This study evaluated the acoustic characteristics of interference tones as experienced by FAA Air Traffic Control Specialists (ATCS's) and pilots who wear headsets with insert type ear pieces. The sound pressure levels (SPL's) of generated tones were measured through the headset at five randomly selected ATCS positions in each of seven Air Route Traffic Control Centers (ARTCC's). The SPL's were compared within and between four frequencies (.5, 1, 2, and 3 KHz) over ten discrete signal power levels. The comparisons demonstrated that SPL's of tones could not be predicted for ARTCC's or for positions within an ARTCC, and that the durations of exposure were brief, i.e., limited to the time needed to remove the headset earpiece from the ear canal. Potential amounts of temporary threshold shifts (TTS's) also were evaluated in a laboratory by checking hearing levels following exposures to tones played with ATCS/pilot communication through the same headset. Audiometric checks of 20 volunteer subjects indicated TTS could be detected following 1 KHz/114 dB/60 and 145 seconds, 2 KHz/108 dB/60 and 145 seconds, and 3 KHz/99 dB/145 seconds exposures, when hearing checks were made within the first 15 minutes. Such extended durations are highly unlikely for pilots and ATCS's and no TTS was detectable following exposures to shorter durations or to other frequencies with equivalent durations.

  11. Alternative splicing interference by xenobiotics.

    PubMed

    Zaharieva, Emanuela; Chipman, J Kevin; Soller, Matthias

    2012-06-14

    The protein coding sequence of most eukaryotic genes (exons) is interrupted by non-coding parts (introns), which are excised in a process termed splicing. To generate a mature messenger RNA (mRNA) hundreds of combinatorial protein-protein and RNA-protein interactions are required to splice out often very large introns with high fidelity and accuracy. Inherent to splicing is the use of alternative splice sites generating immense proteomic diversity from a limited number of genes. In humans, alternative splicing is a major mode of regulating gene expression, occurs in over 90% of genes and is particularly abundant in the brain. Only recently, it has been recognized that the complexity of the splicing process makes it susceptible to interference by various xenobiotics. These compounds include antineoplastic substances, commonly used drugs and food supplements and cause a spectrum of effects ranging from deleterious inhibition of general splicing to highly specific modifications of alternative splicing affecting only certain genes. Alterations in splicing have been implicated in numerous diseases such as cancer and neurodegeneration. Splicing regulation plays an important role in the execution of programmed cell death. The switch between anti- and pro-apoptotic isoforms by alternative splice site selection and misregulation of a number of splicing factors impacts on cell survival and disease. Here, our current knowledge is summarized on compounds interfering with general and alternative splicing and of the current methodology to study changes in these processes relevant to the field of toxicology and future risk assessments.

  12. Optics Technologies for LUVOIR & HabEx: Polarization & Mirror Count

    NASA Astrophysics Data System (ADS)

    Breckinridge, James B.

    2017-01-01

    We show that polarization aberrations and mirror count will limit the optical system performance of LUVOIR and HabEx and thus both their exoplanet science yield and their UV science. In addition we show how increased mirror count reduces optical system transmittance and increases cost in large aperture telescopes. We make the observation that orthogonally polarized light does not interfere to form an intensity image. We show how the two polarization aberrations (diattenuation & and retardance) distort the system PSF, decrease transmittance, and increase the unwanted background above that predicted using scalar models. An optical system corrected for geometric path difference errors is a necessary but not sufficient condition for the perfect image formation needed to directly image terrestrial exoplanets. Geometric (trigonometric) path difference errors are controlled using adaptive optics (tip-tilt & wavefront), active metrology and precision pointing. However, image quality is also determined by several physical optics factors: diffraction, polarization, partial coherence, and chromatism all of which degrade image quality and are not corrected through the control of geometric path difference. The source of physical optics errors lies in the opto-mechanical packaging of optical elements, masks, stops and the thin film coatings needed to obtain high transmittance. Adaptive optics corrects wavefront errors described by geometric or optical path length errors but not those wavefront errors introduced by physical optics. We show that for large telescopes each reflection costs over $100 million to increase the collecting area in order to recover lost SNR. Examples will be shown. The LUVOIR and HabEx systems will need fewer optical surfaces than current systems

  13. Scaling, genetic drift, and clonal interference in the extinction pattern of asexual population

    NASA Astrophysics Data System (ADS)

    Rosas, Alexandre; Gordo, Isabel; Campos, Paulo R. A.

    2005-07-01

    We investigate the dynamics of loss of favorable mutations in an asexual haploid population. In the current work, we consider homogeneous as well as spatially structured population models. We focus our analysis on statistical measurements of the probability distribution of the maximum population size Nsb achieved by those mutations that have not reached fixation. Our results show a crossover behavior which demonstrates the occurrence of two evolutionary regimes. In the first regime, which takes place for small Nsb , the probability distribution is described by a power law with characteristic exponent θd=1.86±0.01 . This power law is not influenced by the rate of beneficial mutations. The second regime, which occurs for intermediate to large values of Nsb , has a characteristic exponent θc which increases as the rate of beneficial mutations grows. These results establish where genetic drift and clonal interference become the main underlying mechanism in the extinction of advantageous mutations.

  14. Improved CDMA Performance Using Parallel Interference Cancellation

    NASA Technical Reports Server (NTRS)

    Simon, Marvin; Divsalar, Dariush

    1995-01-01

    This report considers a general parallel interference cancellation scheme that significantly reduces the degradation effect of user interference but with a lesser implementation complexity than the maximum-likelihood technique. The scheme operates on the fact that parallel processing simultaneously removes from each user the interference produced by the remaining users accessing the channel in an amount proportional to their reliability. The parallel processing can be done in multiple stages. The proposed scheme uses tentative decision devices with different optimum thresholds at the multiple stages to produce the most reliably received data for generation and cancellation of user interference. The 1-stage interference cancellation is analyzed for three types of tentative decision devices, namely, hard, null zone, and soft decision, and two types of user power distribution, namely, equal and unequal powers. Simulation results are given for a multitude of different situations, in particular, those cases for which the analysis is too complex.

  15. [Nonlalocalized interference in multiple-beam interferometer].

    PubMed

    Chen, Hai-Liang; Li, Shu-Guang; Wang, Suo-Ming; Sun, Xin; Li, Xing-Yuan; Zhu, Er-Kuang

    2013-12-01

    The authors studied the nonlocalized interference in multiple-beam interferometer. The light intensity distribution function was obtained. The result shows that the function in the circle center has the same form with localized interference. Numerical simulation method was used to analyse the light intensity distribution function. As the reflection coefficient increases, the stripe becomes sharp, Resolution ratio was improved, while the noise occured around the lower interference index. The noise becomes obviously as the reflection coefficient increases. While changing the receiving screen distance, the simulation result shows that linear relationship exists between inteference index and cosine value of interference stripe dip angle. The mirror spacing can be obtained through the straight line slope. With changing the mirror spacing, the numerical simulation result shows that linear relationship exists between interference index and stripe radii square. The straight slope shows a linear relationship with the mirror spacing.

  16. Phonon-Mediated Nonclassical Interference in Diamond

    NASA Astrophysics Data System (ADS)

    England, Duncan G.; Fisher, Kent A. G.; MacLean, Jean-Philippe W.; Bustard, Philip J.; Heshami, Khabat; Resch, Kevin J.; Sussman, Benjamin J.

    2016-08-01

    Quantum interference of single photons is a fundamental aspect of many photonic quantum processing and communication protocols. Interference requires that the multiple pathways through an interferometer be temporally indistinguishable to within the coherence time of the photon. In this Letter, we use a diamond quantum memory to demonstrate interference between quantum pathways, initially temporally separated by many multiples of the optical coherence time. The quantum memory can be viewed as a light-matter beam splitter, mapping a THz-bandwidth single photon to a variable superposition of the output optical mode and stored phononic mode. Because the memory acts both as a beam splitter and as a buffer, the relevant coherence time for interference is not that of the photon, but rather that of the memory. We use this mechanism to demonstrate nonclassical single-photon and two-photon interference between quantum pathways initially separated by several picoseconds, even though the duration of the photons themselves is just ˜250 fs .

  17. Multipoint linkage map of the human pseudoautosomal region, based on single-sperm typing: Do double crossovers occur during male meiosis?

    SciTech Connect

    Schmitt, K.; Arnheim, N.; Lazzeroni, L.C.; Goradia, T.M.; Lange, K.; Foote, S.; Vollrath, D.; Fisher, E.M.C.; Page, D.C.

    1994-09-01

    Sperm typing was used to measure recombination fractions among pseudoautosomal markers and the beginning of the X/Y-specific sequences located at the pseudoautosomal boundary. These experiments included primer-extension preamplification and PCR followed by allele typing using gel electrophoresis. A newly developed data-analysis program allowed the construction of the first multipoint-linkage sperm-typing map, using results obtained on seven loci from three individuals. The large sample size not only confirmed the increased recombination activity of the pseudoautosomal region but allowed an estimate of interference of recombination to be made. The coefficient of coincidence was calculated to be .26 over a physical distance of only {approximately} 1,800 kb. The observation of a few sperm presumably resulting from double recombination argues that more than one crossover event can occur in this region during male meiosis. 44 refs., 1 fig., 4 tabs.

  18. Attention and visual interference stimulation affect somatosensory processing: a magnetoencephalographic study.

    PubMed

    Lam, K; Kakigi, R; Mukai, T; Yamasaki, H

    2001-01-01

    In our previous study, continuous visual (cartoon and random dot motion) and auditory (music) stimulation changed the somatosensory evoked magnetic fields following electrical stimulation of the median nerve in human subjects. They enhanced the middle-latency components (3M and 4M) generated in the contralateral primary somatosensory cortex, and reduced the MI component generated in the ipsilateral secondary somatosensory cortex. We speculated that such interference effects were caused by activation of polymodal neurons in areas 5 and/or 7 of the parietal lobe as well as in the medial superior temporal region and superior temporal sulcus. However, we could not exclude the effect of attention on such interference effects. In the present study, to know the effect of attention on visual and auditory interference in these changes, we stimulated the bilateral median nerves unilaterally in a random order, and asked subjects to count the number of times the left median nerve was stimulated while visual or auditory interference was applied. Five components (1M-5M) were identified in the hemisphere contralateral to the stimulated nerve and only one component (MI) was found in the ipsilateral hemisphere. The 3M and 4M components (33-75 ms in latency) were enhanced by both attention and visual interference stimulation but not by auditory stimulation. The 5M component (70-115 ms) and MI component (70-133 ms) were enhanced by attention, but were not changed by attention together with visual or auditory interference. Summarizing the results of our previous study and the present study, (1) visual interference alone enhanced the 3M and 4M but reduced the MI, and (2) attention alone also enhanced the 3M and 4M, and enhanced the 5M and MI. As a result, (3) visual interference with attention enhanced the 3M and 4M more, and showed no significant change of the 5M and MI. This was compatible with a summation of the effects caused by visual interference alone and attention alone, but

  19. Counting white blood cells using morphological granulometries

    NASA Astrophysics Data System (ADS)

    Theera-Umpon, Nipon; Gader, Paul D.

    2000-04-01

    We describe a modification of the mixture proportion estimation algorithm based on the granulometric mixing theorem. The modified algorithm is applied to the problem of counting different types of white blood cells in bone marrow images. In principle, the algorithm can be used to count the proportion of cells in each class without explicitly segmenting and classifying them. The direct application of the original algorithm does not converge well for more than two classes. The modified algorithm uses prior statistics to initially segment the mixed pattern spectrum and then applies the one-primitive estimation algorithm to each initial component. Applying the algorithm to one class at a time results in better convergence. The counts produced by the modified algorithm on six classes of cells--myeloblast, promyelocyte, myelocyte, metamyelocyte, band, and PolyMorphoNuclear--are very close to the human expert's numbers; the deviation of the algorithm counts is similar to the deviation of counts produced by human experts. The important technical contributions are that the modified algorithm uses prior statistics for each shape class in place or prior knowledge of the total number of objects in an image, and it allows for more than one primitive from each class.

  20. Sedimentation counting and morphology of Mycoplasma.

    PubMed

    Clark, H W

    1965-11-01

    Clark, Harold W. (The George Washington University School of Medicine, Washington, D.C.). Sedimentation counting and morphology of Mycoplasma. J. Bacteriol. 90:1373-1386. 1965.-The sedimentation technique for counting viral particles was applied to the quantitation and morphological identification of Mycoplasma in broth cultures. Mycoplasma, apparently in their native form, firmly adhered to the surface, when sedimented on glass cover slips or onto electron microscope grids. The sedimented cover slip preparations stained with crystal violet could be readily counted in the light microscope. The cultures sedimented onto electron microscope grids were readily counted at low magnification and provided excellent preparations for morphological examination at higher magnifications. It was found that air-dried Mycoplasma particles were enlarged considerably because of excessive flattening. Fixation of sedimented Mycoplasma particles in diluted OsO(4) prior to air drying yielded a more realistic morphology, with various sizes and shapes in the stages of the growth cycle exhibited. A new technique of differentially staining Mycoplasma colonies on agar plates was developed to facilitate the quantitation of viable colony-forming units for comparison with total counts. The use of plastic or Parafilm gaskets for dry mounting was developed to facilitate the handling and examination of the stained cover slip preparations. The results of this investigation indicated that the growth cycle of some Mycoplasma species includes a stage of hexadic fission with the cleavage of minimal reproductive units (less than 100 mmu) containing a limited deoxyribonucleic acid genetic coding molecule (approximately 4 x 10(6)).

  1. Protecting count queries in study design

    PubMed Central

    Sarwate, Anand D; Boxwala, Aziz A

    2012-01-01

    Objective Today's clinical research institutions provide tools for researchers to query their data warehouses for counts of patients. To protect patient privacy, counts are perturbed before reporting; this compromises their utility for increased privacy. The goal of this study is to extend current query answer systems to guarantee a quantifiable level of privacy and allow users to tailor perturbations to maximize the usefulness according to their needs. Methods A perturbation mechanism was designed in which users are given options with respect to scale and direction of the perturbation. The mechanism translates the true count, user preferences, and a privacy level within administrator-specified bounds into a probability distribution from which the perturbed count is drawn. Results Users can significantly impact the scale and direction of the count perturbation and can receive more accurate final cohort estimates. Strong and semantically meaningful differential privacy is guaranteed, providing for a unified privacy accounting system that can support role-based trust levels. This study provides an open source web-enabled tool to investigate visually and numerically the interaction between system parameters, including required privacy level and user preference settings. Conclusions Quantifying privacy allows system administrators to provide users with a privacy budget and to monitor its expenditure, enabling users to control the inevitable loss of utility. While current measures of privacy are conservative, this system can take advantage of future advances in privacy measurement. The system provides new ways of trading off privacy and utility that are not provided in current study design systems. PMID:22511018

  2. Photon-counting spaceborne altimeter simulator

    NASA Astrophysics Data System (ADS)

    Blazej, Josef

    2004-11-01

    We are presenting of a photon counting laser altimeter simulator. The simulator is designed to be a theoretical and numerical complement for a Technology Demonstrator of the space born laser altimeter for planetary studies built on our university. The European Space Agency has nominated the photon counting altimeter as one of the attractive devices for planetary research. The device should provide altimetry in the range 400 to 1400 km with one meter range resolution under rough conditions - Sun illumination, radiation, etc. The general altimeter concept expects the photon counting principle laser radar. According to this concept, the simulator is based on photon counting radar simulation, which has been enhanced to handle planetary surface roughness, vertical terrain profile and its reflectivity. The simulator is useful complement for any photon counting altimeter both for altimeter design and for measured data analysis. Our simulator enables to model the orbital motion, range, terrain profile, reflectivity, and their influence on the over all energy budget and the ultimate signal to noise ratio acceptable for the altimetry. The simulator can be adopted for various air or space born application.

  3. Crossover from retro to specular Andreev reflections in bilayer graphene

    NASA Astrophysics Data System (ADS)

    Efetov, Dmitri K.; Efetov, Konstantin B.

    2016-08-01

    Ongoing experimental progress in the preparation of ultraclean graphene/superconductor (SC) interfaces enabled the recent observation of specular interband Andreev reflections (ARs) at bilayer graphene (BLG )/NbSe2 van der Waals interfaces [Efetov et al., Nat. Phys. 12, 328 (2016), 10.1038/nphys3583]. Motivated by this experiment we theoretically study the differential conductance across a BLG/SC interface at the continuous transition from high to ultralow Fermi energies EF in BLG. Using the Bogoliubov-de Gennes equations and the Blonder-Tinkham-Klapwijk formalism we derive analytical expressions for the differential conductance across the BLG/SC interface. We find a characteristic signature of the crossover from intraband retro (high EF) to interband specular (low EF) ARs that manifests itself in a strongly suppressed interfacial conductance when the excitation energy |ɛ |=| EF|<Δ (the SC gap). The sharpness of these conductance dips is strongly dependent on the size of the potential step at the BLG/SC interface U0.

  4. Analysis of crossover between local and massive separation on airfoils

    NASA Technical Reports Server (NTRS)

    Barnett, Mark

    1987-01-01

    The occurrence of massive separation on airfoils operating at high Reynolds number poses an important problem to the aerodynamicist. In the present study, the phenomenon of crossover, induced by airfoil thickness, between local separation and massive separation is investigated for low speed (incompressible), symmetric flow past realistic airfoil geometries. This problem is studied both for the infinite Reynolds number asymptotic limit using triple-deck theory and for finite Reynolds number using interacting boundary-layer theory. Numerical results are presented which illustrate how the flow evolves from local to massive separation as the airfoil thickness is increased. The results of the triple-deck and the interacting boundary-layer analyses are found to be in qualitative agreement for the NACA four digit series and an uncambered supercritical airfoil. The effect of turbulence on the evolution of the flow is also considered. Solutions are presented for turbulent flows past a NACA 0014 airfoil and a circular cylinder. For the latter case, the calculated surface pressure distribution is found to agree well with experimental data if the proper eddy pressure level is specified.

  5. Quantum crossover of the switching rate of a modulated oscillator

    NASA Astrophysics Data System (ADS)

    Peano, Vittorio; Guo, Lingzhen; Marthaler, Michael; Dykman, Mark; Schoen, Gerd

    2012-02-01

    Experiments with Josephson bifurcation amplifiers have reached the regime where switching between coexisting stable vibrational states is due to quantum fluctuations. In switching the oscillator goes over the effective dynamical barrier that separates the states. It was found earlier that, for small damping, the barrier height calculated for T->0 is smaller than for T=0. Respectively, the switching rates calculated in these two limits are exponentially different, the effect of fragility. If other parameters are fixed, both barrier heights are proportional to the number of bound quantum states localized mostly in the basin of attraction of the corresponding stable state. Here we show that for large but finite values of the number of states the T=0 solution is stabilized. For some temperature Tc there occurs a sharp crossover to the finite-temperature regime. Our analytical results are corroborated by numerical results.[4pt] [1] Vijay et al., Rev. Sci. Instr. (2009)[0pt] [2] M. Dykman et al., JETP (1988)[0pt] [3] M. Marthaler et al, PRA (2005)

  6. Finite size induces crossover temperature in growing spin chains.

    PubMed

    Sienkiewicz, Julian; Suchecki, Krzysztof; Hołyst, Janusz A

    2014-01-01

    We introduce a growing one-dimensional quenched spin model that bases on asymmetrical one-side Ising interactions in the presence of external field. Numerical simulations and analytical calculations based on Markov chain theory show that when the external field is smaller than the exchange coupling constant J there is a nonmonotonous dependence of the mean magnetization on the temperature in a finite system. The crossover temperature Tc corresponding to the maximal magnetization decays with system size, approximately as the inverse of the Lambert W function. The observed phenomenon can be understood as an interplay between the thermal fluctuations and the presence of the first cluster determined by initial conditions. The effect exists also when spins are not quenched but fully thermalized after the attachment to the chain. By performing tests on real data we conceive the model is in part suitable for a qualitative description of online emotional discussions arranged in a chronological order, where a spin in every node conveys emotional valence of a subsequent post.

  7. Sequential design approaches for bioequivalence studies with crossover designs.

    PubMed

    Potvin, Diane; DiLiberti, Charles E; Hauck, Walter W; Parr, Alan F; Schuirmann, Donald J; Smith, Robert A

    2008-01-01

    The planning of bioequivalence (BE) studies, as for any clinical trial, requires a priori specification of an effect size for the determination of power and an assumption about the variance. The specified effect size may be overly optimistic, leading to an underpowered study. The assumed variance can be either too small or too large, leading, respectively, to studies that are underpowered or overly large. There has been much work in the clinical trials field on various types of sequential designs that include sample size reestimation after the trial is started, but these have seen only little use in BE studies. The purpose of this work was to validate at least one such method for crossover design BE studies. Specifically, we considered sample size reestimation for a two-stage trial based on the variance estimated from the first stage. We identified two methods based on Pocock's method for group sequential trials that met our requirement for at most negligible increase in type I error rate.

  8. Tuning size and thermal hysteresis in bistable spin crossover nanoparticles.

    PubMed

    Galán-Mascarós, José Ramón; Coronado, Eugenio; Forment-Aliaga, Alicia; Monrabal-Capilla, María; Pinilla-Cienfuegos, Elena; Ceolin, Marcelo

    2010-06-21

    Nanoparticles of iron(II) triazole salts have been prepared from water-organic microemulsions. The mean size of the nanoparticles can be tuned down to 6 nm in diameter, with a narrow size distribution. A sharp spin transition from the low spin (LS) to the high spin (HS) state is observed above room temperature, with a 30-40-K-wide thermal hysteresis. The same preparation can yield second generation nanoparticles containing molecular alloys by mixing triazole with triazole derivatives, or from metallic mixtures of iron(II) and zinc(II). In these nanoparticles of 10-15 nm, the spin transition "moves" towards lower temperatures, reaching a 316 K limit for the cooling down transition and maintaining a thermal hysteresis over 15-20-K-wide. The nanoparticles were characterized by dynamic light scattering, TEM, and AFM, after deposition on gold or silicon surfaces. The spin transition was characterized by magnetic susceptibility measurements and EXAFS (in solid samples after solvent removal) and also by the color change between the LS (violet) and HS (colorless) states in an organic solvent suspension. The discovery of bistable magnetic nanoparticles of 6 nm with a wide thermal hysteresis above room temperature showcases the actual possibilities of spin crossover materials for nanotechnological applications.

  9. Quantum-to-classical crossover near quantum critical point

    DOE PAGES

    Vasin, M.; Ryzhov, V.; Vinokur, V. M.

    2015-12-21

    A quantum phase transition (QPT) is an inherently dynamic phenomenon. However, while non-dissipative quantum dynamics is described in detail, the question, that is not thoroughly understood is how the omnipresent dissipative processes enter the critical dynamics near a quantum critical point (QCP). Here we report a general approach enabling inclusion of both adiabatic and dissipative processes into the critical dynamics on the same footing. We reveal three distinct critical modes, the adiabatic quantum mode (AQM), the dissipative classical mode [classical critical dynamics mode (CCDM)], and the dissipative quantum critical mode (DQCM). We find that as a result of the transitionmore » from the regime dominated by thermal fluctuations to that governed by the quantum ones, the system acquires effective dimension d+zΛ(T), where z is the dynamical exponent, and temperature-depending parameter Λ(T)ε[0, 1] decreases with the temperature such that Λ(T=0) = 1 and Λ(T →∞) = 0. Lastly, our findings lead to a unified picture of quantum critical phenomena including both dissipation- and dissipationless quantum dynamic effects and offer a quantitative description of the quantum-to-classical crossover.« less

  10. Blinded placebo crossover study of gabapentin in primary orthostatic tremor.

    PubMed

    Rodrigues, Julian P; Edwards, Dylan J; Walters, Susan E; Byrnes, Michelle L; Thickbroom, Gary W; Stell, Rick; Mastaglia, Frank L

    2006-07-01

    Primary orthostatic tremor (OT) is a rare but disabling condition characterized by leg tremor and feelings of instability during stance. Previous studies have reported a reduction in OT symptoms with gabapentin treatment. In this study, we report on the benefits of gabapentin treatment in a double-blind placebo-controlled crossover study of 6 OT patients. First, the maximally effective gabapentin dosage (600-2,700 mg/day) for each patient was determined during an initial dose-titration phase. Patients were then studied 7 days after drug withdrawal and again after two 2-week periods of treatment with either gabapentin or placebo, using force platform posturography to quantify postural sway and tremor. Other medications for OT were continued unchanged. Symptomatic response was assessed by a patient-rated severity scale and quality of life (QOL) questionnaire. All patients reported an increase in symptoms during the washout phase and symptom reduction (50%-75%) during gabapentin treatment. Tremor amplitude was reduced to 79% +/- 11% and sway area to 71% +/- 11% of the placebo state. QOL improved in all patients, no adverse drug effects were noted, and symptomatic benefit was maintained at follow-up (mean = 19 months). The findings confirm that gabapentin is an effective treatment for OT, reducing both tremor and postural instability and improving quality of life, and support its use as add-on or first-line therapy for OT.

  11. BCS-BEC crossover with unequal-mass fermions

    SciTech Connect

    Diener, Roberto B.; Randeria, Mohit

    2010-03-15

    We investigate the crossover from BCS pairing to molecular Bose-Einstein condensation (BEC) in an atomic gas with two fermion species with masses m{sub {up_arrow}{ne}m{down_arrow}}tuned through a Feshbach resonance. We present results for the T=0 equation of state as a function of the scattering length including the effects of Gaussian fluctuations about the mean field ground state. We compute the ground state energy as a function of m{sub {up_arrow}/}m{sub {down_arrow}}at unitarity and find excellent agreement with the quantum Monte Carlo result for m{sub {up_arrow}/}m{sub {down_arrow}=}6.67 for a {sup 40}K-{sup 6}Li mixture. We show that the dimer scattering length in the BEC limit as a function of m{sub {up_arrow}/}m{sub {down_arrow}}compares well with the exact four-body results of Petrov et al. [J. Phys. B 38, S645 (2005)]. We also derive the condition for trapping frequencies to obtain an unpolarized gas in a harmonic trap.

  12. Finite size induces crossover temperature in growing spin chains

    NASA Astrophysics Data System (ADS)

    Sienkiewicz, Julian; Suchecki, Krzysztof; Hołyst, Janusz A.

    2014-01-01

    We introduce a growing one-dimensional quenched spin model that bases on asymmetrical one-side Ising interactions in the presence of external field. Numerical simulations and analytical calculations based on Markov chain theory show that when the external field is smaller than the exchange coupling constant J there is a nonmonotonous dependence of the mean magnetization on the temperature in a finite system. The crossover temperature Tc corresponding to the maximal magnetization decays with system size, approximately as the inverse of the Lambert W function. The observed phenomenon can be understood as an interplay between the thermal fluctuations and the presence of the first cluster determined by initial conditions. The effect exists also when spins are not quenched but fully thermalized after the attachment to the chain. By performing tests on real data we conceive the model is in part suitable for a qualitative description of online emotional discussions arranged in a chronological order, where a spin in every node conveys emotional valence of a subsequent post.

  13. Quantum-to-classical crossover near quantum critical point

    PubMed Central

    Vasin, M.; Ryzhov, V.; Vinokur, V. M.

    2015-01-01

    A quantum phase transition (QPT) is an inherently dynamic phenomenon. However, while non-dissipative quantum dynamics is described in detail, the question, that is not thoroughly understood is how the omnipresent dissipative processes enter the critical dynamics near a quantum critical point (QCP). Here we report a general approach enabling inclusion of both adiabatic and dissipative processes into the critical dynamics on the same footing. We reveal three distinct critical modes, the adiabatic quantum mode (AQM), the dissipative classical mode [classical critical dynamics mode (CCDM)], and the dissipative quantum critical mode (DQCM). We find that as a result of the transition from the regime dominated by thermal fluctuations to that governed by the quantum ones, the system acquires effective dimension d + zΛ(T), where z is the dynamical exponent, and temperature-depending parameter Λ(T) ∈ [0, 1] decreases with the temperature such that Λ(T = 0) = 1 and Λ(T → ∞) = 0. Our findings lead to a unified picture of quantum critical phenomena including both dissipation- and dissipationless quantum dynamic effects and offer a quantitative description of the quantum-to-classical crossover. PMID:26688102

  14. At grade optical crossover for monolithic optial circuits

    NASA Technical Reports Server (NTRS)

    Jamieson, Robert S. (Inventor)

    1983-01-01

    Planar optical circuits may be made to cross through each other, (thus eliminating extra steps required to fabricate elevated, nonintersecting crossovers) by control of the dimensions of the crossing light conductors (10, 12) to be significantly greater than d=0.89.lambda. and the angle of crossing as nearly 90.degree. as conveniently possible. A light trap may be provided just ahead of the intersection to trap any light being reflected in the source conductor at angles greater than about 45.degree.. The light trap may take the form of triangular shaped portions (16a, 16b) on each side of the source conductor with the far side of the triangular portion receiving incident light at an angle so that incident light will be reflected to the other side, or it may take the form of windows (18a, 18b) in place of the triangular portions. Planar optical circuit boards (21-23) may be fabricated and stacked to form a keyboard (20) with intersecting conductors (26-29) and keyholes (0-9) where conductors merge at the broad side of the circuit boards. These keyholes may be prearranged to form an array or matrix of keyholes.

  15. Flooding and Clostridium difficile Infection: A Case-Crossover Analysis

    PubMed Central

    Lin, Cynthia J.; Wade, Timothy J.; Hilborn, Elizabeth D.

    2015-01-01

    Clostridium difficile is a bacterium that can spread by water. It often causes acute gastrointestinal illness in older adults who are hospitalized and/or receiving antibiotics; however, community-associated infections affecting otherwise healthy individuals have become more commonly reported. A case-crossover study was used to assess emergency room (ER) and outpatient visits for C. difficile infection following flood events in Massachusetts from 2003 through 2007. Exposure status was based on whether or not a flood occurred prior to the case/control date during the following risk periods: 0–6 days, 7–13 days, 14–20 days, and 21–27 days. Fixed-effects logistic regression was used to estimate the risk of diagnosis with C. difficile infection following a flood. There were 129 flood events and 1575 diagnoses of C. difficile infection. Among working age adults (19–64 years), ER and outpatient visits for C. difficile infection were elevated during the 7–13 days following a flood (Odds Ratio, OR = 1.69; 95% Confidence Interval, CI: 0.84, 3.37). This association was more substantial among males (OR = 3.21; 95% CI: 1.01–10.19). Associations during other risk periods were not observed (p < 0.05). Although we were unable to differentiate community-associated versus nosocomial infections, a potential increase in C. difficile infections should be considered as more flooding is projected due to climate change. PMID:26090609

  16. Thermopower of molecular junctions: Tunneling to hopping crossover in DNA

    NASA Astrophysics Data System (ADS)

    Korol, Roman; Kilgour, Michael; Segal, Dvira

    2016-12-01

    We study the electrical conductance G and the thermopower S of single-molecule junctions and reveal signatures of different transport mechanisms: off-resonant tunneling, on-resonant coherent (ballistic) motion, and multi-step hopping. These mechanisms are identified by studying the behavior of G and S while varying molecular length and temperature. Based on a simple one-dimensional model for molecular junctions, we derive approximate expressions for the thermopower in these different regimes. Analytical results are compared to numerical simulations, performed using a variant of Büttiker's probe technique, the so-called voltage-temperature probe, which allows us to phenomenologically introduce environmentally induced elastic and inelastic electron scattering effects, while applying both voltage and temperature biases across the junction. We further simulate the thermopower of GC-rich DNA sequences with mediating A:T blocks and manifest the tunneling-to-hopping crossover in both the electrical conductance and the thermopower, in accord with measurements by Li et al. [Nat. Commun. 7, 11294 (2016)].

  17. Does milk cause constipation? A crossover dietary trial.

    PubMed

    Crowley, Elesa T; Williams, Lauren T; Roberts, Tim K; Dunstan, Richard H; Jones, Peter D

    2013-01-22

    The aims of this study were to: (1) determine whether replacement of cow's milk protein with soy resolves Chronic Functional Constipation (CFC); and (2) investigate the effects of cow's milk β casein A1 and cow's milk β casein A2 on CFC. Children diagnosed with CFC were recruited to one of two crossover trials: Trial 1 compared the effects of cow's milk and soy milk; Trial 2 compared the effects of cow's milk β casein A1 and cow's milk β casein A2. Resolution of constipation was defined as greater than eight bowel motions during a two week intervention. Thirteen children (18 to 144 months) participated in Trial 1 (6 boys, 7 girls). Nine participants who completed the soy epoch all experienced resolution (p < 0.05). Thirty-nine children (21 to 144 months) participated in Trial 2 (25 boys, 14 girls). Resolution of constipation was highest during the washout epoch, 81%; followed by cow's milk β casein A2, 79%; and cow's milk β casein A1, 57%; however, the proportions did not differ statistically. The results of Trial 1 demonstrate an association between CFC and cow's milk consumption but Trial 2 failed to show an effect from type of casein. Some other component in cow's milk common to both A1 and A2 milk may be causing a problem in these susceptible children.

  18. Characterization of Non-Specific Crossover in SPLITT Fractionation

    PubMed Central

    Williams, P. Stephen; Hoyos, Mauricio; Kurowski, Pascal; Salhi, Dorra; Moore, Lee R.; Zborowski, Maciej

    2009-01-01

    Split-flow thin channel (SPLITT) fractionation is a technique for continuous separation of particles or macromolecules in a fluid stream into fractions according to the lateral migration induced by application of a field perpendicular to the direction of flow. Typical applications have involved isolation of different fractions from a polydisperse sample. Some specialized applications involve the separation of the fraction influenced by the transverse field from the fraction that is not. For example, immuno-magnetically labeled biological cells may be separated from non-labeled cells with the application of a transverse magnetic field gradient. In such cases, it may be critically important to minimize contamination of the labeled cells with non-labeled cells while at the same time maximizing the throughput. Such contamination is known as non-specific crossover (NSC) and refers to the real or apparent migration of non-mobile particles or cells across streamlines with the mobile material. The possible mechanisms for NSC are discussed, and experimental results interpreted in terms of shear-induced diffusion (SID) caused by viscous interactions between particles in a sheared flow. It is concluded that SID may contribute to NSC, but that further experiments and mathematical modeling are necessary to more fully explore the phenomenon. PMID:18698797

  19. Quantum-to-classical crossover near quantum critical point

    SciTech Connect

    Vasin, M.; Ryzhov, V.; Vinokur, V. M.

    2015-12-21

    A quantum phase transition (QPT) is an inherently dynamic phenomenon. However, while non-dissipative quantum dynamics is described in detail, the question, that is not thoroughly understood is how the omnipresent dissipative processes enter the critical dynamics near a quantum critical point (QCP). Here we report a general approach enabling inclusion of both adiabatic and dissipative processes into the critical dynamics on the same footing. We reveal three distinct critical modes, the adiabatic quantum mode (AQM), the dissipative classical mode [classical critical dynamics mode (CCDM)], and the dissipative quantum critical mode (DQCM). We find that as a result of the transition from the regime dominated by thermal fluctuations to that governed by the quantum ones, the system acquires effective dimension d+zΛ(T), where z is the dynamical exponent, and temperature-depending parameter Λ(T)ε[0, 1] decreases with the temperature such that Λ(T=0) = 1 and Λ(T →∞) = 0. Lastly, our findings lead to a unified picture of quantum critical phenomena including both dissipation- and dissipationless quantum dynamic effects and offer a quantitative description of the quantum-to-classical crossover.

  20. Quantum-to-classical crossover near quantum critical point.

    PubMed

    Vasin, M; Ryzhov, V; Vinokur, V M

    2015-12-21

    A quantum phase transition (QPT) is an inherently dynamic phenomenon. However, while non-dissipative quantum dynamics is described in detail, the question, that is not thoroughly understood is how the omnipresent dissipative processes enter the critical dynamics near a quantum critical point (QCP). Here we report a general approach enabling inclusion of both adiabatic and dissipative processes into the critical dynamics on the same footing. We reveal three distinct critical modes, the adiabatic quantum mode (AQM), the dissipative classical mode [classical critical dynamics mode (CCDM)], and the dissipative quantum critical mode (DQCM). We find that as a result of the transition from the regime dominated by thermal fluctuations to that governed by the quantum ones, the system acquires effective dimension d + zΛ(T), where z is the dynamical exponent, and temperature-depending parameter Λ(T) ∈ [0, 1] decreases with the temperature such that Λ(T = 0) = 1 and Λ(T → ∞) = 0. Our findings lead to a unified picture of quantum critical phenomena including both dissipation- and dissipationless quantum dynamic effects and offer a quantitative description of the quantum-to-classical crossover.

  1. Measuring Meiotic Crossovers via Multi-Locus Genotyping of Single Pollen Grains in Barley.

    PubMed

    Dreissig, Steven; Fuchs, Jörg; Cápal, Petr; Kettles, Nicola; Byrne, Ed; Houben, Andreas

    2015-01-01

    The detection of meiotic crossovers in crop plants currently relies on scoring DNA markers in a segregating population or cytological visualization. We investigated the feasibility of using flow-sorted haploid nuclei, Phi29 DNA polymerase-based whole-genome-amplification (WGA) and multi-locus KASP-genotyping to measure meiotic crossovers in individual barley pollen grains. To demonstrate the proof of concept, we used 24 gene-based physically mapped single nucleotide polymorphisms to genotype the WGA products of 50 single pollen nuclei. The number of crossovers per chromosome, recombination frequencies along chromosome 3H and segregation distortion were analysed and compared to a doubled haploid (DH) population of the same genotype. The number of crossovers and chromosome wide recombination frequencies show that this approach is able to produce results that resemble those obtained from other methods in a biologically meaningful way. Only the segregation distortion was found to be lower in the pollen population than in DH plants.

  2. Studies on Methanol Crossover in Liquid-Feed Direct Methanol Pem Fuel Cells

    NASA Technical Reports Server (NTRS)

    Narayanan, S. R.

    1995-01-01

    The performance of liquid feed direct methanol fuel cells using various types of Nafion membranes as the solid polymer electrolyte have been studied. The rate of fuel crossover and electrical performance has been measured for cells with Nafion membranes of various thicknesses and equivalent weights. The crossover rate is found to decrease with increasing thickness and applied current. The dependence of crossover rate on current density can be understood in terms of a simple linear diffusion model which suggests that the crossover rate can be influenced by the electrode structure in addition to the membrane. The studies suggest that Nafion EW 1500 is a very promising alternate to Nafion EW 1100 for direct methanol fuel cells.

  3. An end to crossover designs for studies on the effect of sugar substitutes on caries?

    PubMed

    Mäkinen, K K

    2009-01-01

    Clinical trials and laboratory studies involving the administration of oral health treatments and foods have benefited from the observance of the so-called crossover study design. Field experience and a growing number of laboratory experiments have shown, however, that 'blind' reliance on crossover designs may in some instances lead to unexpected results and erroneous conclusions. Some dietary substances, antibiotic agents, and even fluoride applications may have long-term effects that call into question the appropriateness of the washout periods between treatments. Studies have also been conducted on compounds that have turned out to display synergistic effects. When long-term and synergistic effects are simultaneously present in trials involving a crossover design, difficulties may arise in the interpretation of results. This communication uses as an example the long-term clinical and microbiological effects of xylitol and suggests that inclusion of the crossover practice in clinical trials should be separately and carefully contemplated in each instance.

  4. Design evaluation and optimisation in crossover pharmacokinetic studies analysed by nonlinear mixed effects models.

    PubMed

    Nguyen, Thu Thuy; Bazzoli, Caroline; Mentré, France

    2012-05-20

    Bioequivalence or interaction trials are commonly studied in crossover design and can be analysed by nonlinear mixed effects models as an alternative to noncompartmental approach. We propose an extension of the population Fisher information matrix in nonlinear mixed effects models to design crossover pharmacokinetic trials, using a linearisation of the model around the random effect expectation, including within-subject variability and discrete covariates fixed or changing between periods. We use the expected standard errors of treatment effect to compute the power for the Wald test of comparison or equivalence and the number of subjects needed for a given power. We perform various simulations mimicking crossover two-period trials to show the relevance of these developments. We then apply these developments to design a crossover pharmacokinetic study of amoxicillin in piglets and implement them in the new version 3.2 of the r function PFIM.

  5. Fragile-strong fluid crossover and universal relaxation times in a confined hard-disk fluid.

    PubMed

    Yamchi, Mahdi Zaeifi; Ashwin, S S; Bowles, Richard K

    2012-11-30

    We show that a system of hard disks confined to a narrow channel exhibits a fragile-strong fluid crossover located at the maximum of the isobaric heat capacity and that the relaxation times for different channel widths fall onto a single master curve when rescaled by the relaxation times and temperatures of the crossover. Calculations of the configurational entropy and the inherent structure equation of state find that the crossover is related to properties of the jamming landscape for the model but that the Adam-Gibbs relation does not predict the relaxation behavior. We also show that a facilitated dynamics description of the system, where kinetically excited regions are identified with local packing arrangements of the disks, successfully describes the fragile-strong crossover.

  6. Time-dependent couplings and crossover length scales in nonequilibrium surface roughening

    NASA Astrophysics Data System (ADS)

    Pradas, Marc; López, Juan M.; Hernández-Machado, A.

    2007-07-01

    We show that time-dependent couplings may lead to nontrivial scaling properties of the surface fluctuations of the asymptotic regime in nonequilibrium kinetic roughening models. Three typical situations are studied. In the case of a crossover between two different rough regimes, the time-dependent coupling may result in anomalous scaling for scales above the crossover length. In a different setting, for a crossover from a rough to either a flat or damping regime, the time-dependent crossover length may conspire to produce a rough surface, although the most relevant term tends to flatten the surface. In addition, our analysis sheds light into an existing debate in the problem of spontaneous imbibition, where time-dependent couplings naturally arise in theoretical models and experiments.

  7. A Fine-Structure Map of Spontaneous Mitotic Crossovers in the Yeast Saccharomyces cerevisiae

    PubMed Central

    Lee, Phoebe S.; Greenwell, Patricia W.; Dominska, Margaret; Gawel, Malgorzata; Hamilton, Monica; Petes, Thomas D.

    2009-01-01

    Homologous recombination is an important mechanism for the repair of DNA damage in mitotically dividing cells. Mitotic crossovers between homologues with heterozygous alleles can produce two homozygous daughter cells (loss of heterozygosity), whereas crossovers between repeated genes on non-homologous chromosomes can result in translocations. Using a genetic system that allows selection of daughter cells that contain the reciprocal products of mitotic crossing over, we mapped crossovers and gene conversion events at a resolution of about 4 kb in a 120-kb region of chromosome V of Saccharomyces cerevisiae. The gene conversion tracts associated with mitotic crossovers are much longer (averaging about 12 kb) than the conversion tracts associated with meiotic recombination and are non-randomly distributed along the chromosome. In addition, about 40% of the conversion events have patterns of marker segregation that are most simply explained as reflecting the repair of a chromosome that was broken in G1 of the cell cycle. PMID:19282969

  8. Spin crossover in ferropericlase and velocity heterogeneities in the lower mantle.

    PubMed

    Wu, Zhongqing; Wentzcovitch, Renata M

    2014-07-22

    Deciphering the origin of seismic velocity heterogeneities in the mantle is crucial to understanding internal structures and processes at work in the Earth. The spin crossover in iron in ferropericlase (Fp), the second most abundant phase in the lower mantle, introduces unfamiliar effects on seismic velocities. First-principles calculations indicate that anticorrelation between shear velocity (VS) and bulk sound velocity (Vφ) in the mantle, usually interpreted as compositional heterogeneity, can also be produced in homogeneous aggregates containing Fp. The spin crossover also suppresses thermally induced heterogeneity in longitudinal velocity (VP) at certain depths but not in VS. This effect is observed in tomography models at conditions where the spin crossover in Fp is expected in the lower mantle. In addition, the one-of-a-kind signature of this spin crossover in the RS/P (∂ ln VS/∂ ln VP) heterogeneity ratio might be a useful fingerprint to detect the presence of Fp in the lower mantle.

  9. Efficient statistical mapping of avian count data

    USGS Publications Warehouse

    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.

  10. Comparison study of membrane filtration direct count and an automated coliform and Escherichia coli detection system for on-site water quality testing.

    PubMed

    Habash, Marc; Johns, Robert

    2009-10-01

    This study compared an automated Escherichia coli and coliform detection system with the membrane filtration direct count technique for water testing. The automated instrument performed equal to or better than the membrane filtration test in analyzing E. coli-spiked samples and blind samples with interference from Proteus vulgaris or Aeromonas hydrophila.

  11. High Count Rate Electron Probe Microanalysis.

    PubMed

    Geller, Joseph D; Herrington, Charles

    2002-01-01

    Reducing the measurement uncertainty of quantitative analyses made using electron probe microanalyzers (EPMA) requires a careful study of the individual uncertainties from each definable step of the measurement. Those steps include measuring the incident electron beam current and voltage, knowing the angle between the electron beam and the sample (takeoff angle), collecting the emitted x rays from the sample, comparing the emitted x-ray flux to known standards (to determine the k-ratio) and transformation of the k-ratio to concentration using algorithms which includes, as a minimum, the atomic number, absorption, and fluorescence corrections. This paper discusses the collection and counting of the emitted x rays, which are diffracted into the gas flow or sealed proportional x-ray detectors. The representation of the uncertainty in the number of collected x rays collected reduces as the number of counts increase. The uncertainty of the collected signal is fully described by Poisson statistics. Increasing the number of x rays collected involves either counting longer or at a higher counting rate. Counting longer means the analysis time increases and may become excessive to get to the desired uncertainty. Instrument drift also becomes an issue. Counting at higher rates has its limitations, which are a function of the detector physics and the detecting electronics. Since the beginning of EPMA analysis, analog electronics have been used to amplify and discriminate the x-ray induced ionizations within the proportional counter. This paper will discuss the use of digital electronics for this purpose. These electronics are similar to that used for energy dispersive analysis of x rays with either Si(Li) or Ge(Li) detectors except that the shaping time constants are much smaller.

  12. Topical Effect of a Medically Prescribed Pediatric Antibiotic on Dental Biofilm: A Cross-Over, In Situ Study

    PubMed Central

    Pierro, Viviane Santos da Silva; Ferreira, Dennis de Carvalho; de Jesus, Hugo Emiliano; Rosado, Alexandre Soares; Luiz, Ronir Raggio; dos Santos, Kátia Regina Netto; Maia, Lucianne Cople

    2013-01-01

    Objective This study aimed to investigate the possible topical effect of a broad-spectrum antibiotic on dental biofilm formed in situ in the absence or presence of sucrose. Methods A crossover study was conducted in three phases of 14 days each, during which 11 volunteers wore palatal devices containing 6 enamel blocks covered with meshes to allow biofilm formation. Dental blocks were extraorally submitted to a 20% sucrose solution at three different frequencies of exposure (0, 3 and 8 times/day), and to a suspension of amoxicillin/clavulanate potassium (A/CP) or a placebo (P) suspension at an 8-hour time interval application regimen. On the 14th day of each phase, biofilms were collected for microbiological (conventional culture) and molecular (Denaturing Gradient Gel Electrophoresis – DGGE) analyses. Results In the absence of sucrose exposure (SE) and at the 3-time daily frequency, dental biofilms treated with A/CP showed lower total biofilm weight and lower counts of total microbiota than the ones treated with P (p>0.05). A/CP presented higher counts of Candida spp. when compared with P in the presence of SE, especially at the 8-time daily frequency (p<0.05). Considering the DGGE analysis, the mean number of bands was higher for P (p>0.05), regardless of SE. However, DGGE profiles demonstrated large interindividual variability. Conclusion Both conventional culture and DGGE have demonstrated some differences on total microbiota of dental biofilms when exposed to the A/CP or P suspensions, mainly in the absence of sucrose, which suggests a possible topical effect of the sugar-free A/CP suspension on dental biofilm. PMID:23383224

  13. Splitter imperfections in annular split-flow thin separation channels: experimental study of nonspecific crossover.

    PubMed

    Williams, P Stephen; Decker, Keith; Nakamura, Masayuki; Chalmers, Jeffrey J; Moore, Lee R; Zborowski, Maciej

    2003-12-01

    The separation performance of a split-flow thin (SPLITT) separation device depends on uniformity of channel thickness and the precise placement of the flow splitters at fixed distances between the channel walls. The observation of nonspecific crossover, that is, the transport of sample materials across the channel thickness without the influence of an applied field, has routinely been taken to indicate the presence of irregularities in splitter shape or placement. Computational fluid dynamics software may be used to predict the influence of splitter imperfections on nonspecific crossover, where it is assumed that sample transport is by convection alone. A previous study has shown how small inlet splitter imperfections can account for the relatively low levels of nonspecific crossover observed with typical annular SPLITT devices. This study, however, could not distinguish between the possible sources of nonspecific crossover; hydrodynamic lift or shear-induced diffusion could have contributed. To confirm the validity of the computational approach, a series of experiments has been carried out on a channel having a deliberately and severely bent splitter. Nonspecific crossover was measured for a range of inlet and outlet flow rate ratios, with the bent splitter placed at both the channel inlet and outlet. The severity of the splitter distortion was sufficient to produce significant nonspecific crossover over a wide range of flow conditions. Good agreement was found between experiment and prediction based on computational fluid dynamics, with experiment generally showing only slightly higher crossover than prediction. The quantitative agreement for this extreme case suggests that the contribution to nonspecific crossover due to geometrical imperfections can be well described using computational fluid dynamics.

  14. Measures of Child Well-Being in Utah, 2002: Counting the Kids Who Count on Us. Utah KIDS COUNT.

    ERIC Educational Resources Information Center

    Haven, Terry, Ed.

    This Kids Count report details statewide trends in the well-being of Utah's children. The statistical portrait is based on 29 indicators of children's well-being in five areas: (1) child health and safety (prenatal care, low birthweight, infant mortality, child injury deaths, injury-related hospital discharges, child abuse, childhood…

  15. Suppression: sound and light interference with targeting

    NASA Astrophysics Data System (ADS)

    VanMeenen, Kirsten M.; Short, Kenneth R.; DeMarco, Robert M.; Chua, Florence B.; Janal, Malvin N.; Servatius, Richard J.

    2006-05-01

    Civilian law enforcement and military operations on urban terrain (MOUT) regularly enter into unknown situations where some unidentified subset of the populace may possess armaments that may be used against them. Ultimately, the most relevant test of the effectiveness of non-lethal energies in these situations is their ability to interfere with the targeting of those weapons on the friendly forces. It is also the test that offers the most immediate and tangible reward in the prevention of personnel injuries. Perceptual interference (e.g., light-induced flash blindness) or distractions from loud noises may contribute to targeting interference. How much do various energies or perceptual interventions actually interfere with targeting? We have devised a program of experimentation that allows for the pure and precise measurement of interference with the targeting process by any of a broad range of energies and stimuli. Our primary focus has been on sound and light interference with targeting, and experiments toward that purpose are described here. As expected, targeting accuracy decreased and targeting latency increased as the distance from fixation point to the target increased. The light flash interfered more with shots at more distant targets. Furthermore, as the angle between the fixation point and the flash increased, targeting latency increased but targeting accuracy was unaffected. Thus, light interference is greatest when the flash is not at the point of fixation. These studies suggest that foveal flashes are less disruptive than peripheral flashes, and that disruption increases as targeting task demands increase.

  16. Applying contextual interference to the Pawlata roll.

    PubMed

    Smith, P J; Davies, M

    1995-12-01

    Contextual interference is manipulated by changing the practice order of a number of similar motor tasks, so that the learning context of each interferes with that of the other. The effect has been found to generalize to baseball batting, badminton serving and volleyball skills. The present study examined whether this practice technique could be applied to a Pawlata roll in a kayak. The study was further motivated by the fact that many instructors in Britain currently advocate learning the Pawlata roll in one direction only to a criterion of accuracy, thereafter transferring to the opposite direction. Contextual interference literature predicts that skill retention would be better served by practising on alternate sides. Accordingly, 16 undergraduate students with no kayaking experience were randomly allocated to either a low contextual interference group, which followed U'ren's (1993) recommendations, or a high contextual interference group, which practised the skill on alternate sides. The high contextual interference group took less time to acquire the skill, and were also quicker to achieve successful performance in retention (full roll) and transfer (half roll) tests, regardless of the direction of the roll, 1 week later. The time savings in practice were not expected, as acquisition under high contextual interference was improved rather than impaired. This finding suggests that bilateral transfer was increased by randomizing practice. These results are worthy of further investigation, in that they suggest that the recommended training methods may not be optimal.

  17. Retrospective Revaluation of Associative Retroactive Cue Interference

    PubMed Central

    Miguez, Gonzalo; Laborda, Mario A.; Miller, Ralph R.

    2013-01-01

    Two fear-conditioning experiments with rats assessed whether retrospective revaluation, which has been observed in cue competition (i.e., when compounded cues are followed with an outcome), can also be observed in retroactive cue interference (i.e., when different cues are reinforced in separate phases with the same outcome). Experiment 1 found that after inducing retroactive cue interference (i.e., X-outcome followed by A-outcome), nonreinforced presentations of the interfering cue (A) decreases interference with responding to the target cue (X), just as has been observed in retrospective revaluation experiments in cue competition. Using the opposite manipulation (i.e., adding reinforced presentations of A), Experiment 2 demonstrated that after inducing retroactive cue interference, additional reinforced presentations of the interfering cue (A) increases interference with responding to the target cue (X); alternatively stated, the amount of interference increases with the amount of training with the interfering cue. Thus, both types of retrospective revaluation occur in retroactive cue competition. The results are discussed in terms of the possibility that similar associative mechanisms underlie cue competition and cue interference. PMID:24142799

  18. Optical planar waveguide for cell counting

    NASA Astrophysics Data System (ADS)

    LeBlanc, John; Mueller, Andrew J.; Prinz, Adrian; Butte, Manish J.

    2012-01-01

    Low cost counting of cells has medical applications in screening, military medicine, disaster medicine, and rural healthcare. In this report, we present a shallow, buried, planar waveguide fabricated by potassium ion exchange in glass that enables low-cost and rapid counting of metal-tagged objects that lie in the evanescent field of the waveguide. Laser light transmitted through the waveguide was attenuated proportionately to the presence of metal-coated microstructures fabricated from photoresist. This technology enables the low-cost enumeration of cells from blood, urine, or other biofluids.

  19. A Hop-Count Analysis Scheme for Avoiding Wormhole Attacks in MANET

    PubMed Central

    Jen, Shang-Ming; Laih, Chi-Sung; Kuo, Wen-Chung

    2009-01-01

    MANET, due to the nature of wireless transmission, has more security issues compared to wired environments. A specific type of attack, the Wormhole attack does not require exploiting any nodes in the network and can interfere with the route establishment process. Instead of detecting wormholes from the role of administrators as in previous methods, we implement a new protocol, MHA, using a hop-count analysis from the viewpoint of users without any special environment assumptions. We also discuss previous works which require the role of administrator and their reliance on impractical assumptions, thus showing the advantages of MHA. PMID:22408566

  20. A Hop-Count Analysis Scheme for Avoiding Wormhole Attacks in MANET.

    PubMed

    Jen, Shang-Ming; Laih, Chi-Sung; Kuo, Wen-Chung

    2009-01-01

    MANET, due to the nature of wireless transmission, has more security issues compared to wired environments. A specific type of attack, the Wormhole attack does not require exploiting any nodes in the network and can interfere with the route establishment process. Instead of detecting wormholes from the role of administrators as in previous methods, we implement a new protocol, MHA, using a hop-count analysis from the viewpoint of users without any special environment assumptions. We also discuss previous works which require the role of administrator and their reliance on impractical assumptions, thus showing the advantages of MHA.

  1. Analysis of Crossovers in the Interbeat Sequences of Elderly Individuals and Heart Failure Patients

    NASA Astrophysics Data System (ADS)

    Muñoz-Diosdado, A.; del Río Correa, J. L.

    2006-09-01

    Many physical and biological systems exhibit complex behavior characterized by long-range power-law correlations. Detrended fluctuation analysis (DFA) is a scaling analysis method that provides a scaling parameter to represent the correlation properties of a signal. The study of interbeat sequences with the DFA method has revealed the presence of crossovers associated with physiological aging and heart with failure; the hinges present in the crossover region from both the elderly healthy individuals and the patients with congestive heart failure (CHF) are in opposite directions. The interbeat sequences of healthy young persons do not show crossovers. In this paper we study interbeat time series of healthy young and elderly persons and patients with CHF. We use the DFA-m method, where m refers to the order of the polynomial function used for the fitting. For instance, DFA-2 filters linear trends and DFA-3 filters quadratic trends. We found that the presence of the crossovers and the direction of the hinges are conserved when we apply the DFA method for different values of m. Therefore we conclude that the DFA-m method is a reliable method to accurately quantify correlations in interbeat time series even if there are polynomial trends. We can characterize the crossovers and we can conclude that the crossovers are not a result of the trends; they are part of the system dynamics.

  2. Local chromosome context is a major determinant of crossover pathway biochemistry during budding yeast meiosis

    PubMed Central

    Medhi, Darpan; Goldman, Alastair SH; Lichten, Michael

    2016-01-01

    The budding yeast genome contains regions where meiotic recombination initiates more frequently than in others. This pattern parallels enrichment for the meiotic chromosome axis proteins Hop1 and Red1. These proteins are important for Spo11-catalyzed double strand break formation; their contribution to crossover recombination remains undefined. Using the sequence-specific VMA1-derived endonuclease (VDE) to initiate recombination in meiosis, we show that chromosome structure influences the choice of proteins that resolve recombination intermediates to form crossovers. At a Hop1-enriched locus, most VDE-initiated crossovers, like most Spo11-initiated crossovers, required the meiosis-specific MutLγ resolvase. In contrast, at a locus with lower Hop1 occupancy, most VDE-initiated crossovers were MutLγ-independent. In pch2 mutants, the two loci displayed similar Hop1 occupancy levels, and VDE-induced crossovers were similarly MutLγ-dependent. We suggest that meiotic and mitotic recombination pathways coexist within meiotic cells, and that features of meiotic chromosome structure determine whether one or the other predominates in different regions. DOI: http://dx.doi.org/10.7554/eLife.19669.001 PMID:27855779

  3. Empirical power and sample size calculations for cluster-randomized and cluster-randomized crossover studies.

    PubMed

    Reich, Nicholas G; Myers, Jessica A; Obeng, Daniel; Milstone, Aaron M; Perl, Trish M

    2012-01-01

    In recent years, the number of studies using a cluster-randomized design has grown dramatically. In addition, the cluster-randomized crossover design has been touted as a methodological advance that can increase efficiency of cluster-randomized studies in certain situations. While the cluster-randomized crossover trial has become a popular tool, standards of design, analysis, reporting and implementation have not been established for this emergent design. We address one particular aspect of cluster-randomized and cluster-randomized crossover trial design: estimating statistical power. We present a general framework for estimating power via simulation in cluster-randomized studies with or without one or more crossover periods. We have implemented this framework in the clusterPower software package for R, freely available online from the Comprehensive R Archive Network. Our simulation framework is easy to implement and users may customize the methods used for data analysis. We give four examples of using the software in practice. The clusterPower package could play an important role in the design of future cluster-randomized and cluster-randomized crossover studies. This work is the first to establish a universal method for calculating power for both cluster-randomized and cluster-randomized clinical trials. More research is needed to develop standardized and recommended methodology for cluster-randomized crossover studies.

  4. Crossover versus Stabilometric Platform for the Treatment of Balance Dysfunction in Parkinson's Disease: A Randomized Study

    PubMed Central

    Frazzitta, G.; Bossio, F.; Maestri, R.; Palamara, G.; Bera, R.; Ferrazzoli, D.

    2015-01-01

    Balance dysfunctions are a major challenge in the treatment of Parkinson's disease (PD). Previous studies have shown that rehabilitation can play a role in their treatment. In this study, we have compared the efficacy of two different devices for balance training: stabilometric platform and crossover. We have enrolled 60 PD patients randomly assigned to two groups. The first one (stabilometric group) performed a 4-week cycle of balance training, using the stabilometric platform, whereas the second one (crossover group) performed a 4-week cycle of balance training, using the crossover. The outcome measures used were Unified Parkinson's Disease Rating Scale (UPDRS) part II, Berg Balance Scale (BBS), Timed Up and Go (TUG), and Six Minutes Walking Test (6MWT). Results showed that TUG, BBS, and UPDRS II improved in both groups. There was not difference in the efficacy of the two balance treatments. Patients in both groups improved also the meters walked in the 6MWT at the end of rehabilitation, but the improvement was better for patients performing crossover training. Our results show that the crossover and the stabilometric platform have the same effect on balance dysfunction of Parkinsonian patients, while crossover gets better results on the walking capacity. PMID:26583142

  5. Crossover versus Stabilometric Platform for the Treatment of Balance Dysfunction in Parkinson's Disease: A Randomized Study.

    PubMed

    Frazzitta, G; Bossio, F; Maestri, R; Palamara, G; Bera, R; Ferrazzoli, D

    2015-01-01

    Balance dysfunctions are a major challenge in the treatment of Parkinson's disease (PD). Previous studies have shown that rehabilitation can play a role in their treatment. In this study, we have compared the efficacy of two different devices for balance training: stabilometric platform and crossover. We have enrolled 60 PD patients randomly assigned to two groups. The first one (stabilometric group) performed a 4-week cycle of balance training, using the stabilometric platform, whereas the second one (crossover group) performed a 4-week cycle of balance training, using the crossover. The outcome measures used were Unified Parkinson's Disease Rating Scale (UPDRS) part II, Berg Balance Scale (BBS), Timed Up and Go (TUG), and Six Minutes Walking Test (6MWT). Results showed that TUG, BBS, and UPDRS II improved in both groups. There was not difference in the efficacy of the two balance treatments. Patients in both groups improved also the meters walked in the 6MWT at the end of rehabilitation, but the improvement was better for patients performing crossover training. Our results show that the crossover and the stabilometric platform have the same effect on balance dysfunction of Parkinsonian patients, while crossover gets better results on the walking capacity.

  6. Monitoring cellular mechanosensing using time-correlated single photon counting

    NASA Astrophysics Data System (ADS)

    Tabouillot, Tristan; Gullapalli, Ramachandra; Butler, Peter J.

    2006-10-01

    Endothelial cells (ECs) convert mechanical stimuli into chemical signaling pathways to regulate their functions and properties. It is hypothesized that perturbation of cellular structures by force is accompanied by changes in molecular dynamics. In order to address these fundamental issues in mechanosensation and transduction, we have developed a hybrid multimodal microscopy - time-correlated single photon counting (TCSPC) spectroscopy system intended to determine time- and position dependent mechanically-induced changes in the dynamics of molecules in live cells as determined from fluorescence lifetimes and autocorrelation analysis (fluorescence correlation spectroscopy). Colocalization of cell-structures and mechanically-induced changes in molecular dynamics can be done in post-processing by comparing TCSPC data with 3-D models generated from total internal reflection fluorescence (TIRF), differential interference contrast (DIC), epifluorescence, and deconvolution. We present control experiments in which the precise location of the apical cell membrane with respect to a confocal probe is assessed using information obtainable only from TCSPC. Such positional accuracy of TCSPC measurements is essential to understanding the role of the membrane in mechanotransduction. We predict that TCSPC will become a useful method to obtain high temporal and spatial resolution information on localized mechanical phenomena in living endothelial cells. Such insight into mechanotransduction phenomenon may uncover the origins of mechanically-related diseases such as atherosclerosis.

  7. Calcium from salmon and cod bone is well absorbed in young healthy men: a double-blinded randomised crossover design

    PubMed Central

    2010-01-01

    Background Calcium (Ca) - fortified foods are likely to play an important role in helping the consumer achieve an adequate Ca intake, especially for persons with a low intake of dairy products. Fish bones have a high Ca content, and huge quantities of this raw material are available as a by-product from the fish industry. Previously, emphasis has been on producing high quality products from fish by-products by use of bacterial proteases. However, documentation of the nutritional value of the enzymatically rinsed Ca-rich bone fraction remains unexplored. The objective of the present study was to assess the bioavailability of calcium in bones of Atlantic salmon (oily fish) and Atlantic cod (lean fish) in a double-blinded randomised crossover design. Methods Ca absorption was measured in 10 healthy young men using 47Ca whole body counting after ingestion of a test meal extrinsically labelled with the 47Ca isotope. The three test meals contained 800 mg of Ca from three different calcium sources: cod bones, salmon bones and control (CaCO3). Results Mean Ca absorption (± SEE) from the three different Ca sources were 21.9 ± 1.7%, 22.5 ± 1.7% and 27.4 ± 1.8% for cod bones, salmon bones, and control (CaCO3), respectively. Conclusion We conclude that bones from Atlantic salmon and Atlantic cod are suitable as natural Ca sources in e.g. functional foods or as supplements. PMID:20646299

  8. Heparin versus low molecular weight heparin K 2165 in chronic hemodialysis patients: a randomized cross-over study.

    PubMed

    Borm, J J; Krediet, R; Sturk, A; ten Cate, J W

    1986-01-01

    Ten patients on chronic intermittent hemodialysis treatment received either unfractionated heparin or low molecular weight (LMW) heparin K 2165 in a single-blinded randomized cross-over study to assess: effects on hemostasis and ex vivo platelet functions, and effectiveness, i.e. prevention of fibrin formation in the extracorporeal circuit. The 20 dialysis treatments were without untoward side effects, for both drugs used. The variation in the plasma anti-Xa activities was significantly less during K 2165 treatment than during heparinization. No differences between the drugs were observed regarding the Ivy bleeding time, platelet count and platelet aggregation (spontaneous, and induced by ADP and collagen). Plasma platelet factor 4 levels did not increase under K 2165 to such an extent as under heparin. Both drugs did not influence the plasma levels of beta-thromboglobulin, thromboxane B2 and platelet serotonin content. K 2165 did not affect platelet adhesion to collagen, in contrast to heparin which substantially inhibited platelet adhesion. Under both treatments, 4 minor clots were observed in 4 artificial kidneys, despite plasma anti-Xa levels in between 0.19 and 0.46 U/ml. K 2165 may therefore be considered as effective an anticoagulant as heparin, with less effects on ex vivo platelet functions.

  9. Gaseous air pollution and acute myocardial infarction mortality in Hong Kong: A time-stratified case-crossover study

    NASA Astrophysics Data System (ADS)

    Lin, Hualiang; An, Qingzhu; Luo, Chao; Pun, Vivian C.; Chan, Chi Sing; Tian, Linwei

    2013-09-01

    Acute myocardial infarction (AMI) is a common disease with serious consequences in mortality and morbidity. An association between gaseous air pollution and AMI has been suggested, but the epidemiological evidence is still limited. For the study period 1998-2010, daily counts of AMI deaths were collected, as well as daily air pollution data including concentrations of particulates (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3) and carbon monoxide (CO) were also obtained. The associations between gaseous air pollutants and AMI mortality were estimated using time-stratified case-crossover analyses. NO2 and SO2 were found to be significantly associated with increased AMI mortality. The odds ratios (ORs) were 1.0455 (95% confidence interval (CI): 1.017-1.0748) and 1.0256 (95% CI: 1.0027-1.0489) for an interquartile range (IQR) increase in the current day's NO2 and SO2 concentration, respectively, and this association persisted in 2-pollutant models; and no association was observed for CO and O3. It is likely that exposure to elevated ambient NO2 and SO2 air pollution contributed to increased AMI mortality.

  10. Fano interference in two-photon transport

    NASA Astrophysics Data System (ADS)

    Xu, Shanshan; Fan, Shanhui

    2016-10-01

    We present a general input-output formalism for the few-photon transport in multiple waveguide channels coupled to a local cavity. Using this formalism, we study the effect of Fano interference in two-photon quantum transport. We show that the physics of Fano interference can manifest as an asymmetric spectral line shape in the frequency dependence of the two-photon correlation function. The two-photon fluorescence spectrum, on the other hand, does not exhibit the physics of Fano interference.

  11. Gas Interference in Sucker Rod Pump

    NASA Astrophysics Data System (ADS)

    Samad, Abdus

    2010-10-01

    Commonly used artificial lift or dewatering system is sucker rod pump and gas interference of the pump is the biggest issue in the oil and gas industry. Gas lock or fluid pound problems occur due to the gas interference when the pump has partially or completely unfilled plunger barrel. There are several techniques available in the form of patents to solve these problems but those techniques have positive as well as negative aspects. Some of the designs rely on the leakage and some of the designs rely on the mechanical arrangements etc to break the gas lock. The present article compares the existing gas interference handling techniques.

  12. Neurogenesis-mediated forgetting minimizes proactive interference

    PubMed Central

    Epp, Jonathan R.; Silva Mera, Rudy; Köhler, Stefan; Josselyn, Sheena A.; Frankland, Paul W.

    2016-01-01

    Established memories may interfere with the encoding of new memories, particularly when existing and new memories overlap in content. By manipulating levels of hippocampal neurogenesis, here we show that neurogenesis regulates this form of proactive interference. Increasing hippocampal neurogenesis weakens existing memories and, in doing so, facilitates the encoding of new, conflicting (but not non-conflicting) information in mice. Conversely, decreasing neurogenesis stabilizes existing memories, and impedes the encoding of new, conflicting information. These results suggest that reduced proactive interference is an adaptive benefit of neurogenesis-induced forgetting. PMID:26917323

  13. Wave and Particle in Molecular Interference Lithography

    SciTech Connect

    Juffmann, Thomas; Truppe, Stefan; Geyer, Philipp; Major, Andras G.; Arndt, Markus; Deachapunya, Sarayut; Ulbricht, Hendrik

    2009-12-31

    The wave-particle duality of massive objects is a cornerstone of quantum physics and a key property of many modern tools such as electron microscopy, neutron diffraction or atom interferometry. Here we report on the first experimental demonstration of quantum interference lithography with complex molecules. Molecular matter-wave interference patterns are deposited onto a reconstructed Si(111) 7x7 surface and imaged using scanning tunneling microscopy. Thereby both the particle and the quantum wave character of the molecules can be visualized in one and the same image. This new approach to nanolithography therefore also represents a sensitive new detection scheme for quantum interference experiments.

  14. Burst interference in TDMA radio systems

    NASA Astrophysics Data System (ADS)

    Lei, Z.; Chen, M.-X.; Feher, K.

    1985-12-01

    Burst interference is inherent in TDMA subscriber radio and satellite communications systems. Spectral and interference properties of burst modulated signals are investigated. Owing to the burst mode operation of the TDMA system its spectrum spreads; this spread increases with the increase of burst gating rate and the decrease of the burst length. A theoretical derivation of the Pe = f(Eb/N0; I) performance, computer simulation and experimental results of IJF-OQPSK and conventional QPSK burst operated systems are presented. The performance of these systems in the presence of burst mode TDMA co-channel and adjacent channel interference (I) is evaluated.

  15. Diet restriction in migraine, based on IgG against foods: A clinical double-blind, randomised, cross-over trial

    PubMed Central

    Alpay, Kadriye; Ertaş, Mustafa; Orhan, Elif Kocasoy; Üstay, Didem Kanca; Lieners, Camille; Baykan, Betül

    2010-01-01

    Introduction: It is well-known that specific foods trigger migraine attacks in some patients. We aimed to investigate the effect of diet restriction, based on IgG antibodies against food antigens on the course of migraine attacks in this randomised, double blind, cross-over, headache-diary based trial on 30 patients diagnosed with migraine without aura. Methods: Following a 6-week baseline, IgG antibodies against 266 food antigens were detected by ELISA. Then, the patients were randomised to a 6-week diet either excluding or including specific foods with raised IgG antibodies, individually. Following a 2-week diet-free interval after the first diet period, the same patients were given the opposite 6-week diet (provocation diet following elimination diet or vice versa). Patients and their physicians were blinded to IgG test results and the type of diet (provocation or elimination). Primary parameters were number of headache days and migraine attack count. Of 30 patients, 28 were female and 2 were male, aged 19–52 years (mean, 35 ± 10 years). Results: The average count of reactions with abnormally high titre was 24 ± 11 against 266 foods. Compared to baseline, there was a statistically significant reduction in the number of headache days (from 10.5 ± 4.4 to 7.5 ± 3.7; P < 0.001) and number of migraine attacks (from 9.0 ± 4.4 to 6.2 ± 3.8; P < 0.001) in the elimination diet period. Conclusion: This is the first randomised, cross-over study in migraineurs, showing that diet restriction based on IgG antibodies is an effective strategy in reducing the frequency of migraine attacks. PMID:20647174

  16. ATP bioluminescence rapid detection of total viable count in soy sauce.

    PubMed

    Yan, Shou-Lei; Miao, Su-Na; Deng, Shao-Ya; Zou, Min-Juan; Zhong, Fo-Sheng; Huang, Wen-Biao; Pan, Si-Yi; Wang, Qing-Zhang

    2012-01-01

    The adenosine triphosphate (ATP) bioluminescence rapid determination method may be useful for enumerating the total viable count (TVC) in soy sauce, as it has been previously used in food and beverages for sanitation with good precision. However, many factors interfere with the correlation between total aerobic plate counts and ATP bioluminescence. This study investigated these interfering factors, including ingredients of soy sauce and bacteria at different physiological stages. Using the ATP bioluminescence method, TVC was obtained within 4 h, compared to 48 h required for the conventional aerobic plate count (APC) method. Our results also indicated a high correlation coefficient (r = 0.90) between total aerobic plate counts and ATP bioluminescence after filtration and resuscitation with special medium. The limit of quantification of the novel detection method is 100 CFU/mL; there is a good linear correlation between the bioluminescence intensity and TVC in soy sauce in the range 1 × 10(2) -3 × 10(4) CFU/mL and even wider. The method employed a luminescence recorder (Tristar LB-941) and 96-well plates and could analyse 50-100 samples simultaneously at low cost. In this study, we evaluated and eliminated the interfering factors and made the ATP bioluminescence rapid method available for enumerating TVC in soy sauce.

  17. Coherent transport through spin-crossover magnet Fe2 complexes

    NASA Astrophysics Data System (ADS)

    Huang, Jing; Xie, Rong; Wang, Weiyi; Li, Qunxiang; Yang, Jinlong

    2015-12-01

    As one of the most promising building blocks in molecular spintronics, spin crossover (SCO) complexes have attracted increasing attention due to their magnetic bistability between the high-spin (HS) and low-spin (LS) states. Here, we explore the electronic structures and transport properties of SCO magnet Fe2 complexes with three different spin-pair configurations, namely [LS-LS], [LS-HS], and [HS-HS], by performing extensive density functional theory calculations combined with the non-equilibrium Green's function technique. Our calculations clearly reveal that the SCO magnet Fe2 complexes should display two-step spin transitions triggered by external stimuli, i.e. temperature or light, which confirm the previous phenomenological model and agree well with previous experimental measurements. Based on the calculated transport results, we observe a nearly perfect spin-filtering effect and negative differential resistance (NDR) behavior integrated in the SCO magnet Fe2 junction with the [HS-HS] configuration. The current through the [HS-HS] SCO magnet Fe2 complex under a small bias voltage is mainly contributed by the spin-down electrons, which is significantly larger than those of the [LS-LS] and [LS-HS] cases. The bias-dependent transmissions are responsible for the observed NDR effect. These theoretical findings suggest that SCO Fe2 complexes hold potential applications in molecular spintronic devices.As one of the most promising building blocks in molecular spintronics, spin crossover (SCO) complexes have attracted increasing attention due to their magnetic bistability between the high-spin (HS) and low-spin (LS) states. Here, we explore the electronic structures and transport properties of SCO magnet Fe2 complexes with three different spin-pair configurations, namely [LS-LS], [LS-HS], and [HS-HS], by performing extensive density functional theory calculations combined with the non-equilibrium Green's function technique. Our calculations clearly reveal that the SCO

  18. Randomized Polypill Crossover Trial in People Aged 50 and Over

    PubMed Central

    Wald, David S.; Morris, Joan K.; Wald, Nicholas J.

    2012-01-01

    Background A Polypill is proposed for the primary prevention of cardiovascular disease in people judged to be at risk on account of their age alone. Its efficacy in reducing cholesterol and blood pressure is uncertain. Methods We conducted a randomized double-blind placebo-controlled crossover trial of a Polypill among individuals aged 50+ without a history of cardiovascular disease and compared the reductions with those predicted from published estimates of the effects of the individual drugs. Participants took the Polypill (amlodipine 2.5 mg, losartan 25 mg, hydrochlorothiazide 12.5 mg and simvastatin 40 mg) each evening for 12 weeks and a placebo each evening for 12 weeks in random sequence. The mean within-person differences in blood pressure and low density lipoprotein (LDL) cholesterol at the end of each 12 week period were determined. Results 84 out of 86 participants completed both treatment periods. The mean systolic blood pressure was reduced by 17.9 mmHg (95% CI, 15.7–20.1) on the Polypill, diastolic blood pressure by 9.8 mmHg (8.1–11.5), and LDL cholesterol by 1.4 mmol/L (1.2–1.6), reductions of 12%, 11%, and 39% respectively. The results were almost identical to those predicted; 18.4 mmHg, 9.7 mmHg, and 1.4 mmol/L respectively. Conclusion The Polypill resulted in the predicted reductions in blood pressure and LDL cholesterol. Long term reductions of this magnitude would have a substantial effect in preventing heart attacks and strokes. Trial Registration Controlled-Trials.com ISRCTN36672232 PMID:22815989

  19. Pharmacokinetic-pharmacodynamic crossover comparison of two levodopa extension strategies.

    PubMed

    LeWitt, Peter A; Jennings, Danna; Lyons, Kelly E; Pahwa, Rajesh; Rabinowicz, Adrian L; Wang, James; Guarnieri, Maria; Hubble, Jean P; Murck, Harold

    2009-07-15

    Controlled-release carbidopa and levodopa (CL-CR) and the combination of carbidopa, levodopa, and entacapone (CLE) are used for extending levodopa (L-dopa) effects. In a randomized, open-label crossover study of 17 PD subjects with wearing-off responses, we compared 8-hour L-dopa pharmacokinetics (PK) and clinical effects after two doses of CL-CR (50 and 200 mg, respectively) and CLE (37.7, 150, 200 mg, respectively). PK analysis revealed the anticipated near-equivalent mean L-dopa area-under-the-concentration-curve values (639,490 ng min/mL for two doses of CLE, and 662,577 for CL-CR, P = 0.86). The mean hourly fluctuation index for L-dopa concentration was 235% for CLE and 196% for CL-CR (P = 0.004). The mean maximal concentration for the first CLE dose was 1,926 +/- 760 ng/mL and for CL-CR, 1,840 +/- 889 (P = 0.33). During the PK studies, the mean time that L-dopa concentration was > or =1,000 ng/mL for CLE was 291 +/- 88 minutes and for CL-CR, 306 +/- 86 (P = 0.33). The mean percent-time in "off" state was 18% for CLE and 28% for CL-CR (P = 0.017), "on state without dyskinesia" was 64% for CLE and 65% for CL-CR (P = 0.803), and "on state with nontroublesome dyskinesia" was 18% for CLE and 7% for CL-CR (P = 0.03). Despite less "off" time with CLE, both formulations demonstrated similar mean PK values and marked intersubject PK variability.

  20. Clarithromycin in GABA-related Hypersomnolence: A Randomized, Crossover Trial

    PubMed Central

    Trotti, Lynn Marie; Saini, Prabhjyot; Bliwise, Donald L.; Freeman, Amanda A.; Jenkins, Andrew; Rye, David B.

    2016-01-01

    Objective Some central hypersomnolence syndromes are associated with a positive allosteric modulator of GABA-A receptors in cerebrospinal fluid. Negative allosteric modulators of GABA-A receptors, including clarithromycin, have been reported to reduce sleepiness in these patients. We sought to systematically assess the effects of clarithromycin on objective vigilance and subjective sleepiness. Methods This was a five-week, randomized, placebo-controlled, double-blind, crossover trial of clarithromycin 500 mg with breakfast and lunch, in patients with hypersomnolence syndromes (excluding narcolepsy with cataplexy) and evidence for abnormal cerebrospinal fluid potentiation of GABA-A receptors. The study occurred at a university-affiliated medical center. The primary outcome measure was median reaction time on the psychomotor vigilance task (PVT) at week 2 in each condition. Secondary outcomes included the Epworth Sleepiness Scale, Stanford Sleepiness Scale, Functional Outcomes of Sleep, Pittsburgh Sleep Quality Index, the SF-36, and additional PVT measures. Results Twenty-three patients began treatment. Three patients dropped out, and final analyses were performed on twenty complete cases. Median reaction time was not significantly different between clarithromycin and placebo. Subjective measures of sleepiness were significantly improved on clarithromycin versus placebo. Altered taste perception occurred, but was the only side effect more common on clarithromycin than placebo. No serious adverse events occurred. Interpretation Subjective sleepiness, but not psychomotor vigilance, improved during a two-week course of clarithromycin. Although additional studies are needed, this suggests that clarithromycin may be a reasonable treatment option in patients with treatment-refractory hypersomnolence. This trial was registered at clinicaltrials.gov (NCT01146600) and supported by the American Sleep Medicine Foundation. PMID:26094838