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Sample records for affected sib pair

  1. LOD wars: The affected-sib-pair paradigm strikes back!

    SciTech Connect

    Farrall, M.

    1997-03-01

    In a recent letter, Greenberg et al. aired their concerns that the affected-sib-pair (ASP) approach was becoming excessively popular, owing to misconceptions and ignorance of the properties and limitations of both the ASP and the classic LOD-score approaches. As an enthusiast of using the ASP approach to map susceptibility genes for multifactorial traits, I would like to contribute a few comments and explanatory notes in defense of the ASP paradigm. 18 refs.

  2. Reply to Farrall. LOD wars: The affected-sib-pair paradigm strikes back!

    SciTech Connect

    Greenberg, D.A.; Hodge, S.E.; Vieland, V.J.; Spence, M.A.

    1997-03-01

    Farrall, in his comments about our previous letter, eloquently points out some of the advantages of affected-sib-pair (ASP) analysis. It may surprise him to learn that we do not disagree with most of his comments, but we do feel that a few of them could be potentially misleading. Farrall says that {open_quotes}ASP tests are nonparametric{close_quote} in the limited sense that the investigator does not have to declare (or have prior knowledge of) an explicit set of genetic parameters before undertaking a meaningful analysis. He could have added that one does not have the option of changing genetic parameters. One does not have to declare genetic parameters, because the design of the test is such that certain assumptions are inherent in the method. These assumptions are not obvious - and even may not be known - in the nonparametric methods. However, they are still there. 4 refs.

  3. Efficient strategies for genome scanning using maximum-likelihood affected-sib-pair analysis

    SciTech Connect

    Holmans, P.; Craddock, N.

    1997-03-01

    Detection of linkage with a systematic genome scan in nuclear families including an affected sibling pair is an important initial step on the path to cloning susceptibility genes for complex genetic disorders, and it is desirable to optimize the efficiency of such studies. The aim is to maximize power while simultaneously minimizing the total number of genotypings and probability of type I error. One approach to increase efficiency, which has been investigated by other workers, is grid tightening: a sample is initially typed using a coarse grid of markers, and promising results are followed up by use of a finer grid. Another approach, not previously considered in detail in the context of an affected-sib-pair genome scan for linkage, is sample splitting: a portion of the sample is typed in the screening stage, and promising results are followed up in the whole sample. In the current study, we have used computer simulation to investigate the relative efficiency of two-stage strategies involving combinations of both grid tightening and sample splitting and found that the optimal strategy incorporates both approaches. In general, typing half the sample of affected pairs with a coarse grid of markers in the screening stage is an efficient strategy under a variety of conditions. If Hardy-Weinberg equilibrium holds, it is most efficient not to type parents in the screening stage. If Hardy-Weinberg equilibrium does not hold (e.g., because of stratification) failure to type parents in the first stage increases the amount of genotyping required, although the overall probability of type I error is not greatly increased, provided the parents are used in the final analysis. 23 refs., 4 figs., 5 tabs.

  4. Two-locus diseas models with two marker loci: The power of affected-sib-pair tests

    SciTech Connect

    Knapp, M.; Seuchter, S.A.; Bauer, M.P.

    1994-11-01

    Recently, Schork et al. found that two-trait-locus, two-marker-locus (parametric) linkage analysis can provide substantially more linkage information than can standard one-trait-locus, one-marker-locus methods. However, because of the increased burden of computation, Schork et al. do not expect that their approach will be applied in an initial genome scan. Further, the specification of a suitable two-locus segregation model can be crucial. Affected-sib-pair tests are computationally simple and do not require an explicit specification of the disease model. In the past, however, these tests mainly have been applied to data with a single marker locus. Here, we consider sib-pair tests that make it possible to analyze simultaneously two marker loci. The power of these tests is investigated for different (epistatic and heterogeneous) two-trait-locus models, each trait locus being linked to one of the marker loci. We compare these tests both with the test that is optimal for a certain model and with the strategy that analyzes each marker locus separately. The results indicate that a straightforward extension of the well-known mean test for two marker loci can be much more powerful than single-marker-locus analysis and that its power is only slightly inferior to the power of the optimal test. 21 refs., 5 figs., 2 tabs.

  5. Affected-sib-pair analyses reveal support of prior evidence for a susceptibility locus for bipolar disorder, on 21q

    SciTech Connect

    Detera-Wadleigh, S.D.; Badner, J.A.; Goldin, L.R.

    1996-06-01

    In 22 multiplex pedigrees screened for linkage to bipolar disorder, by use of 18 markers on chromosome 21q, single-locus affected-sib-pair (ASP) analysis detected a high proportion (57%-62%) of alleles shared identical by descent (IBD), with P values of .049-.0008 on nine marker loci. Multilocus ASP analyses revealed locus trios in the distal region between D21S270 and D21S171, with excess allele sharing (nominal P values <.01) under two affection-status models, ASM I (bipolars and schizoaffectives) and ASM II (ASM I plus recurrent unipolars). In addition, under ASM I, the proximal interval spanned by D21S1436 and D21S65 showed locus trios with excess allele sharing (nominal P values of .03-.0003). These findings support prior evidence that a susceptibility locus for bipolar disorder is on 21q. 38 refs., 4 tabs.

  6. Genetic copy number variants in sib pairs both affected with schizophrenia

    PubMed Central

    2010-01-01

    Background Schizophrenia is a complex disorder with involvement of multiple genes. Methods In this study, genome-wide screening for DNA copy-number variations (CNVs) was conducted for ten pairs, a total of 20 cases, of affected siblings using oligonucleotide array-based CGH. Results We found negative symptoms were significantly more severe (p < 0.05) in the subgroup that harbored more genetic imbalance (n ≧ 13, n = number of CNV-disrupted genes) as compared with the subgroup with fewer CNVs (n ≦ 6), indicating that the degree of genetic imbalance may influence the severity of the negative symptoms of schizophrenia. Four central nervous system (CNS) related genes including CCAAT/enhancer binding protein, delta (CEBPD, 8q11.21), retinoid × receptor, alpha (RXRA, 9q34.2), LIM homeobox protein 5 (LHX5, 12q24.13) and serine/threonine kinase 11 (STK11, 19p13.3) are recurrently (incidence ≧ 16.7%) disrupted by CNVs. Two genes, PVR (poliovirus receptor) and BU678720, are concordantly deleted in one and two, respectively, pairs of co-affected siblings. However, we did not find a significant association of this BU678720 deletion and schizophrenia in a large case-control sample. Conclusions We conclude that the high genetic loading of CNVs may be the underlying cause of negative symptoms of schizophrenia, and the CNS-related genes revealed by this study warrant further investigation. PMID:20064257

  7. Affected sib-pair interval mapping and exclusion for complex genetic traits: Inferring identity by descent status from relatives

    SciTech Connect

    Hauser, E.R.; Boehnke, M.; Guo, S.W.

    1994-09-01

    Affected sib-pair (ASP) methods provide a useful approach for the initial genetic mapping of complex diseases for which mode of inheritance is uncertain. Risch described a method for interval mapping and exclusion based on the ratio lambda comparing disease risk in the first degree relatives of affected individuals to disease risk in the general population. He assumed marker identity by descent (IBD) status for the ASP could be deduced from parental genotypes. For late onset diseases such as type 2 diabetes, parents may be dead or otherwise unavailable, so that marker IBD status generally cannot be inferred with certainty. Guo has developed efficient methods for probabilistic determination of marker IBD sharing for two or more loci. We have combined and extended the methods of Risch and Guo to carry out interval mapping and exclusion when parents are missing but other relatives such as additional siblings are available. Our method is based on calculating the likelihood of marker data of the ASP and their relatives conditional on the disease status of the ASP, as a function of lambda and the position of the disease locus within the genetic map. We currently are using this method to compare the information to detect or exclude linkage provided by various types of ASP nuclear families -- zero, one, or two typed parents and zero, one, two, or more additional siblings -- as a function of sample size, marker density and informativity, and risk ratio lambda.

  8. Power of sib-pair and sib-trio linkage analysis with assortative mating and multiple disease loci

    SciTech Connect

    Sribney, W.M.; Swift, M. )

    1992-10-01

    Sib-pair linkage analysis has been proposed for identifying genes that predispose to common diseases. The authors have shown that the presence of assortative mating and multiple disease-susceptibility loci (genetic heterogeneity) can increase the required sample size for affected-affected sib pairs several fold over the sample size required under random mating. They propose a new test statistic based on sib trios composed of either one unaffected and two affected siblings or one affected and two unaffected siblings. The sample-size requirements under assortative mating and multiple disease loci for these sib-trio statistics are much smaller, under most conditions, than the corresponding sample sizes for sib pairs. Study designs based on data from sib trios with one or two affected members are recommended whenever assortative mating and genetic heterogeneity are suspected. 31 refs.

  9. A combined analysis of D22S278 marker alleles in affected sib-pairs: Support for a susceptibility locus for schizophrenia at chromosome 22q12

    SciTech Connect

    Gill, M.; Vallada, H.; Collier, D.

    1996-02-16

    Several groups have reported weak evidence for linkage between schizophrenia and genetic markers located on chromosome 22q using the lod score method of analysis. However these findings involved different genetic markers and methods of analysis, and so were not directly comparable. To resolve this issue we have performed a combined analysis of genotypic data from the marker D22S278 in multiply affected schizophrenic families derived from 11 independent research groups worldwide. This marker was chosen because it showed maximum evidence for linkage in three independent datasets. Using the affected sib-pair method as implemented by the program ESPA, the combined dataset showed 252 alleles shared compared with 188 alleles not shared (chi-square 9.31, 1df, P = 0.001) where parental genotype data was completely known. When sib-pairs for whom parental data was assigned according to probability were included the number of alleles shared was 514.1 compared with 437.8 not shared (chi-square 6.12, 1df, P = 0.006). Similar results were obtained when a likelihood ratio method for sib-pair analysis was used. These results indicate that there may be a susceptibility locus for schizophrenia at 22q12. 27 refs., 3 tabs.

  10. A novel framework for sib pair linkage analysis.

    PubMed

    Poznik, G David; Adamska, Katarzyna; Xu, Xin; Krolewski, Andrzej S; Rogus, John J

    2006-02-01

    Sib pair linkage analysis of a dichotomous trait is a popular method for narrowing the search for genes that influence complex diseases. Although the pedigree structures are uncomplicated and the underlying genetic principles straightforward, a surprising degree of complexity is involved in implementing a sib pair study and interpreting the results. Ascertainment may be based on affected, discordant, or unaffected sib pairs, as well as on pairs defined by threshold values for quantitative traits, such as extreme discordant sib pairs. To optimize power, various domain restrictions and null hypotheses have been proposed for each of these designs, yielding a wide array of choices for the analyst. To begin, we systematically classify the major sources of discretion in sib pair linkage analysis. Then, we extend the work of Kruglyak and Lander (1995), to bring the various forms into a unified framework and to facilitate a more general approach to the analysis. Finally, we describe a new, freely available computer program, Splat (Sib Pair Linkage Analysis Testing), that can perform any sib pair statistical test currently in use, as well as any user-defined test yet to be proposed. Splat uses the expectation maximization algorithm to calculate maximum-likelihood estimates of sharing (subject to user-specified conditions) and then plots LOD scores versus chromosomal position. It includes a novel grid-scanning capability that enables simultaneous visualization of multiple test statistics. This can lead to further insight into the genetic basis of the disease process under consideration. In addition, phenotype definitions can be modified without the recalculation of inheritance vectors, thereby providing considerable flexibility for exploratory analysis. The application of Splat will be illustrated with data from studies on the genetics of diabetic nephropathy. PMID:16358216

  11. Transmission-Ratio Distortion and Allele Sharing in Affected Sib Pairs: A New Linkage Statistic with Reduced Bias, with Application to Chromosome 6q25.3

    PubMed Central

    Lemire, Mathieu; Roslin, Nicole M.; Laprise, Catherine; Hudson, Thomas J.; Morgan, Kenneth

    2004-01-01

    We studied the effect of transmission-ratio distortion (TRD) on tests of linkage based on allele sharing in affected sib pairs. We developed and implemented a discrete-trait allele-sharing test statistic, Sad, analogous to the Spairs test statistic of Whittemore and Halpern, that evaluates an excess sharing of alleles at autosomal loci in pairs of affected siblings, as well as a lack of sharing in phenotypically discordant relative pairs, where available. Under the null hypothesis of no linkage, nuclear families with at least two affected siblings and one unaffected sibling have a contribution to Sad that is unbiased, with respect to the effects of TRD independent of the disease under study. If more distantly related unaffected individuals are studied, the bias of Sad is generally reduced compared with that of Spairs, but not completely. Moreover, Sad has higher power, in some circumstances, because of the availability of unaffected relatives, who are ignored in affected-only analyses. We discuss situations in which it may be an efficient use of resources to genotype unaffected relatives, which would give insights for promising study designs. The method is applied to a sample of pedigrees ascertained for asthma in a chromosomal region in which TRD has been reported. Results are consistent with the presence of transmission distortion in that region. PMID:15322985

  12. Multipoint interval mapping of quantitative trait loci, using sib pairs

    SciTech Connect

    Fulker, D.W.; Cherny, S.S.; Cardon, L.R.

    1995-05-01

    The sib-pair interval-mapping procedure of Fulker and Cardon is extended to take account of all available marker information on a chromosome simultaneously. The method provides a computationally fast multipoint analysis of sib-pair data, using a modified Haseman-Elston approach. It gives results very similar to those of the earlier interval-mapping procedure when marker information is relatively uniform and a coarse map is used. However, there is substantial improvement over the original method when markers differ in information content and/or when a dense map is employed. The method is illustrated by using simulated sib-pair data. 14 refs., 4 figs., 2 tabs.

  13. Efficiency of typing unaffected relatives in an affected-sib-pair linkage study with single-locus and multiple tightly linked markers

    SciTech Connect

    Holmans, P.; Clayton, D.

    1995-11-01

    In an affected-sib-pair study, the parents are often unavailable for typing, particularly for diseases of late onset. In many cases, however, it is possible to sample unaffected siblings. It is therefore desirable to assess the contribution of such siblings to the power of such a study. The likelihood ratio introduced by Risch and improved by Holmans was extended to incorporate data from unaffected siblings. Tests based on two likelihoods were considered: the full likelihood of the data, based on the identity-by-descent (IBD) sharing states of the entire sibship, and a pseudolikelihood based on the IBD sharing states of the affected pair only, using the unaffected siblings to infer parental genotypes. The latter approach was found to be more powerful, except when penetrance was high. Typing an unaffected sibling, or just one parent, was found to give only a small increase in power except when the PIC of the marker was low. Even then, typing an unaffected relative increased the overall number of individuals that had to be typed to achieve a given power. If there is no highly informative marker locus in the area under study, it may be possible to {open_quotes}build{close_quotes} one by combining the alleles from two or more neighboring tightly linked loci into haplotypes. Typing two loci gave a sizeable power increase over a single locus, but typing further loci gave much smaller gains. Building haplotypes will introduce phase uncertainties, with the result that such a system will yield less power than will a single locus with the same number of alleles. This power loss was small, however, and did not affect the conclusions regarding the worth of typing unaffected relatives. 14 refs., 2 figs., 11 tabs.

  14. Affected-sib-pair mapping of a novel susceptibility gene to insulin-dependent diabetes mellitus (IDDM8) on chromosome 6q25-q27

    SciTech Connect

    Luo, D.F.; Bui, M.M.; Muir, A.

    1995-10-01

    Affected-sib-pair analyses were performed using 104 Caucasian families to map genes that predispose to insulin-dependent diabetes mellitus (IDDM). We have obtained linkage evidence for D6S446 (maximum lod score [MLS] = 2.8) and for D6S264 (MLS = 2.0) on 6q25q27. Together with a previously reported data set, linkage can be firmly established (MLS = 3.4 for D6S264), and the disease locus has been designated IDDM8. With analysis of independent families, we confirmed linkage evidence for the previously identified IDDM3 (15q) and DDM7 (2q). We also typed additional markers in the regions containing IDDM3, IDDM4, IDDM5, and IDDM8. Preliminary linkage evidence for a novel region on chromosome 4q (D4S1566) has been found in 47 Florida families (P < .03). We also found evidence of linkage for two regions previously identified as potential linkages in the Florida subset: D3S1303 on 3q (P < .04) and D7S486 on 7q (P < .03). We could not confirm linkage with eight other regions (D1S191, D1S412, D4S1604, D8S264, D8S556, D1OS193, D13S158, and D18S64) previously identified as potential linkages. 26 refs., 1 fig., 4 tabs.

  15. The immunoglobulin heavy-chain variable region in insulin-dependent diabetes mellitus: affected-sib-pair analysis and association studies.

    PubMed Central

    Veijola, R.; Knip, M.; Puukka, R.; Reijonen, H.; Cox, D. W.; Ilonen, J.

    1996-01-01

    We have analyzed immunoglobulin heavy-chain variable-region (VH) polymorphisms and genetic susceptibility to insulin-dependent diabetes mellitus (IDDM) by using a set of polymorphic loci that span approximately 1,000 kb of the VH region on chromosome 14q32. One hundred one Finnish families with at least two children affected with IDDM were studied. Conventional RFLPs determined by hybridization were used, since no microsatellite repeat markers have been available for this gene region. No evidence for linkage between the VH genes and IDDM could be obtained from haplotype-sharing analysis among the 133 diabetic sib pairs. The frequencies of various VH genotypes were also compared between 101 familial IDDM cases and 114 controls derived from the Finnish background population. The distribution of the genotypes at the VH2-B5 locus was significantly different between these groups (P=.004), the 3.4/3.4 genotype being less common in the IDDM cases. In addition, a different genotype distribution at the VH5-B2 locus was observed in the diabetic subjects (P = .022). When the IDDM cases were stratified by presence or absence of the high-risk HLA-DQB1*0302 allele, no differences in VH genotype frequencies were observed between the 0302-positive and 0302-negative cases. In the transmission test for linkage disequilibrium (TDT), no differences were found between the expected and observed frequencies of the transmitted alleles at the VH2-B5 or VH5-B2 locus. In conclusion, significant differences in VH genotype distributions were observed between the familial IDDM cases and the controls, but the observed associations could not be confirmed by the TDT. Haplotype sharing analysis provided no evidence for genetic linkage between the VH gene region and IDDM. Images Figure 1 PMID:8755935

  16. Complete multipoint sib-pair analysis of qualitative and quantitative traits

    SciTech Connect

    Kruglyak, L.; Lander, E.S.

    1995-08-01

    Sib-pair analysis is an increasingly important tool for genetic dissection of complex traits. Current methods for sib-pair analysis are primarily based on studying individual genetic markers one at a time and thus fail to use the full inheritance information provided by multipoint linkage analysis. In this paper, we describe how to extract the complete multipoint inheritance information for each sib pair. We then describe methods that use this information to map loci affecting traits, thereby providing a unified approach to both qualitative and quantitative traits. Specifically, complete multipoint approaches are presented for (1) exclusion mapping of qualitative traits; (2) maximum-likelihood mapping of qualitative traits; (3) information-content mapping, showing the extent to which all inheritance information has been extracted at each location in the genome; and (4) quantitative-trait mapping, by two parametric methods and one nonparametric method. In addition, we explore the effects of marker density, marker polymorphism, and availability of parents on the information content of a study. We have implemented the analysis methods in a new computer package, MAPMAKER/SIBS. With this computer package, complete multipoint analysis with dozens of markers in hundreds of sib pairs can be carried out in minutes. 25 refs., 8 figs.

  17. The phenotypic difference discards sib-pair QTL linkage information

    SciTech Connect

    Wright, F.A. |

    1997-03-01

    Kruglyak and Lander provide an important synthesis of methods for (IBD) sib-pair linkage mapping, with an emphasis on the use of complete multipoint inheritance information for each sib pair. These procedures are implemented in the computer program MAPMAKER/SIBS, which performs interval mapping for dichotomous and quantitative traits. The authors present three methods for mapping quantitative trait loci (QTLs): a variant of the commonly used Haseman-Elston regression approach, a maximum-likelihood procedure involving variance components, and a rank-based nonparametric procedure. These approaches and related work use the magnitude of the difference in the sibling phenotype values for each sib pair as the observation for analysis. Linkage is detected if siblings sharing more alleles IBD have similar phenotypes (i.e., a small difference in the phenotype values), while siblings sharing fewer alleles IBD have less similar phenotypes. Such techniques have been used to detect linkage for a number of quantitative traits. However, the exclusive reliance on the phenotypic differences may be due in large part to historical inertia. A likelihood argument is presented here to show that, under certain classical assumptions, the phenotypic differences do not contain the full likelihood information for QTL mapping. Furthermore, considerable gains in power to detect linkage can be achieved with an expanded likelihood model. The development here is related to previous work, which incorporates the full set of phenotypic data using likelihood and robust quasi-likelihood methods. The purpose of this letter is not to endorse a particular approach but to spur research in alternative and perhaps more powerful linkage tests. 17 refs.

  18. Consanguinity and the sib-pair method: An approach using identity by descent between and within individuals

    SciTech Connect

    Genin, E.; Clerget-Darpoux, F.

    1996-11-01

    To test for linkage between a trait and a marker, one can consider identical marker alleles in related individuals, for instance, sibs. For recessive diseases, it has been shown that some information may be gained from the identity by descent (IBD) of the two alleles of an affected inbred individual at the marker locus. The aim of this paper is to extend the sib-pair method of linkage analysis to the situation of sib pairs sampled from consanguineous populations. This extension takes maximum advantage of the information provided by both the IBD pattern between sibs and allelic identity within each sib of the pair. This is possible through the use of the condensed identity coefficients. Here, we propose a new test of linkage based on a {Chi}{sup 2}. We compare the performance of this test with that of the classical {Chi}{sup 2} test based on the distribution of sib pairs sharing 0, 1, or 2 alleles IBD. For sib pairs from first-cousin matings, the proposed test can better detect the role of a disease-susceptibility (DS) locus. Its power is shown to be greater than that of the classical test, especially for models where the DS allele may be common and incompletely penetrant; that is to say for situations that may be encountered in multifactorial diseases. A study of the impact of inbreeding on the expected proportions of sib pairs sharing 0, 1, or 2 alleles IBD is also performed here. Ignoring inbreeding, when in fact inbreeding exists, increases the rate of type I errors in tests of linkage. 21 refs., 8 figs., 9 tabs.

  19. Genome-wide search for type 2 diabetes in Japanese affected sib-pairs confirms susceptibility genes on 3q, 15q, and 20q and identifies two new candidate Loci on 7p and 11p.

    PubMed

    Mori, Yasumichi; Otabe, Shuichi; Dina, Christian; Yasuda, Kazuki; Populaire, Céline; Lecoeur, Cécile; Vatin, Vincent; Durand, Emmanuelle; Hara, Kazuo; Okada, Terumasa; Tobe, Kazuyuki; Boutin, Philippe; Kadowaki, Takashi; Froguel, Philippe

    2002-04-01

    The genetic background that predisposes the Japanese population to type 2 diabetes is largely unknown. Therefore, we conducted a 10-cM genome-wide scan for type 2 diabetes traits in the 359 affected individuals from 159 families, yielding 224 affected sib-pairs of Japanese origin. Nonparametric multipoint linkage analyses performed in the whole population showed one suggestive linked region on 11p13-p12 (maximum logarithm of odds score [MLS] 3.08, near Pax6) and seven potentially linked regions (MLS >1.17) at 1p36-p32, 2q34, 3q26-q28, 6p23, 7p22-p21, 15q13-q21, and 20q12-q13 (near the gene for hepatocyte nuclear factor-4alpha [HNF-4alpha]). Subset analyses according to maximal BMI and early age at diagnosis added suggestive evidence of linkage with type 2 diabetes at 7p22-p21 (MLS 3.51), 15q13-q21 (MLS 3.91), and 20q12-q13 (MLS 2.32). These results support previous indication for linkage found on chromosome 3q, 15q, and 20q in other populations and identifies two new potential loci on 7p and 11p that may confer genetic risk for type 2 diabetes in the Japanese population. PMID:11916952

  20. Using discordant sib pairs to map loci for qualitative traits with high sibling recurrence risk.

    PubMed

    Rogus, J J; Krolewski, A S

    1996-12-01

    A common approach for detecting genetic linkage using siblings is to collect affected sib pairs (ASPs) and to identify markers where allele sharing exceeds expectation. Alternatively, markers can be analyzed in discordant sib pairs (DSPs) for allele sharing below expectation. Relative to the ASP approach, according to Risch, the power of the DSP approach increases with sibling recurrence risk, the two approaches being equally effective at 50% recurrence risk. However, with many diseases associated with more moderate sibling recurrence risk, less emphasis has been placed on the use of DSPs and the development of the underlying theory. In this paper, we expand the work of Risch to provide a more general foundation for DSP studies, since power can be quite high under the appropriate conditions. For example, in some highly affected populations, such as the diabetes-prone Pima Indians, sibling recurrence risk can be very large and, thus, DSPs ideal. Similarly, as we show through simulation, DSPs are preferable for diabetic nephropathy due to a 70% recurrence rate among siblings with insulin-dependent diabetes mellitus. Following the diabetic nephropathy example, we consider more systematically the situations in which DSPs can provide an efficient alternative to ASPs. PMID:8940283

  1. Genetic association mapping based on discordant sib pairs: the discordant-alleles test.

    PubMed

    Boehnke, M; Langefeld, C D

    1998-04-01

    Family-based tests of association provide the opportunity to test for an association between a disease and a genetic marker. Such tests avoid false-positive results produced by population stratification, so that evidence for association may be interpreted as evidence for linkage or causation. Several methods that use family-based controls have been proposed, including the haplotype relative risk, the transmission-disequilibrium test, and affected family-based controls. However, because these methods require genotypes on affected individuals and their parents, they are not ideally suited to the study of late-onset diseases. In this paper, we develop several family-based tests of association that use discordant sib pairs (DSPs) in which one sib is affected with a disease and the other sib is not. These tests are based on statistics that compare counts of alleles or genotypes or that test for symmetry in tables of alleles or genotypes. We describe the use of a permutation framework to assess the significance of these statistics. These DSP-based tests provide the same general advantages as parent-offspring trio-based tests, while being applicable to essentially any disease; they may also be tailored to particular hypotheses regarding the genetic model. We compare the statistical properties of our DSP-based tests by computer simulation and illustrate their use with an application to Alzheimer disease and the apolipoprotein E polymorphism. Our results suggest that the discordant-alleles test, which compares the numbers of nonmatching alleles in DSPs, is the most powerful of the tests we considered, for a wide class of disease models and marker types. Finally, we discuss advantages and disadvantages of the DSP design for genetic association mapping. PMID:9529345

  2. Multipoint methods for linkage analysis of quantitative trait loci in sib pairs

    SciTech Connect

    Cardon, L.R. |; Cherny, S.S.; Fulker, D.W.

    1994-09-01

    The sib-pair method of Haseman and Elston is widely used for linkage analysis of quantitative traits. The method requires no assumptions concerning the mode of transmission of the trait, it is robust with respect to genetic heterogeneity, and it is computationally efficient. However, the practical usefulness of the method is limited by its statistical power, requiring large numbers of sib paris and highly informative markers to detect genetic loci of only moderate effect size. We have developed a family of interval mapping procedures which dramatically increase the statistical power of the classical sib-pair approach. The methods make use of information from pairs of markers which flank a putative quantitative trait locus (QTL) in order to estimate the location and effect size of the QTL. Here we describe an extension of the interval mapping procedure which takes into account all available marker information on a chromosome simultaneously, rather than just pairs of markers. The method provides a computationally fast approximation to full multipoint analysis of sib-pair data using a modified Haserman-Elston approach. It gives very similar results to the earlier interval mapping procedure when marker information is relatively uniform and a coarse map is used. However, there is a substantial improvement over the original method when markers differ in information content and when a dense map is employed. The method is illustrated using real and simulated sib-pair data.

  3. Multipoint linkage analysis using sib pairs: A interval mapping approach for dichotomous outcomes

    SciTech Connect

    Olson, J.M.

    1995-03-01

    I propose an interval mapping approach suitable for a dichotomous outcome, with emphasis on samples of affected sib pairs. The method computes a lod score for each of a set of locations in the interval between two flanking markers and takes as its estimate of trait-locus location the maximum lod score in the interval, provided it exceeds the prespecified critical value. Use of the method depends on prior knowledge of the genetic model for the disease only through available estimates of recurrence risk to relatives of affected individuals. The method gives an unbiased estimate of location, provided the recurrence risks are correctly specified and provided the marker identity-by-descent probabilities are jointly, rather than individually, estimated. I also discuss use of the method for traits determined by two loci and give an approximation that has good power for a wide range of two-locus models. 25 refs., 2 figs., 9 tabs.

  4. Mapping quantitative trait loci with extreme discordant sib pairs: Sampling considerations

    SciTech Connect

    Risch, N.J.; Zhang, H.

    1996-04-01

    Elsewhere we have proposed the use of extreme discordant sib pairs (EDSPs) for mapping quantitative trait loci in humans. Here we present sample sizes necessary to achieve a given level of power with this study design, as well as the number of sibs that need to be screened to obtain the required sample. Further, we present simple formulas for adjusting sample sizes to account for variable significance levels and power, as well as the density and informativeness of linkage markers in a multipoint sib-pair analysis. We conclude that with EDSPs, the most powerful study design, the smallest genetic effect detectable with a realistic sample size is {approximately}10% of the variance of the trait. 10 refs., 6 tabs.

  5. The power of interval mapping of quantitative trait loci, using selected sib pairs

    SciTech Connect

    Cardon, L.R.; Fulker, D.W.

    1994-10-01

    The interval-mapping procedure of Fulker and Cardon for analysis of a quantitative-trait loci (QTL) is extended for application to selected samples of sib pairs. Phenotypic selection of sib pairs, which is known to yield striking increases in power when a single marker is used, provides further increases in power when the interval-mapping approach is used. The greatest benefits of the combined approach are apparent with coarse maps, where QTLs of relatively modest (15%-20%) heritability can be detected with widely spaced markers (40-60 cM apart) in reasonably sized sibling samples. Useful information concerning QTL location is afforded by interval mapping in both selected and unselected samples. 12 refs., 3 figs., 2 tabs.

  6. Mapping quantitative-trait loci in humans by use of extreme concordant sib pairs: Selected sampling by parental phenotypes

    SciTech Connect

    Zhang, Heping; Risch, N.

    1996-10-01

    In two previous articles, we have considered sample sizes required to detect linkage for mapping quantitative-trait loci in humans, using extreme discordant sib pairs. Here, we examine further the use of extreme concordant sib pairs but consider the effect of parents` phenotypes. Sample sizes necessary to obtain a power of 80% with concordant sib pairs at a significance level of .0001 are given, stratified by parental phenotypes. When there is no residual correlation between sibs, the parental phenotypes have little impact on the sample sizes. When residual correlations between sibs exist, we show, however, that power can be considerably reduced by including extreme sib pairs when the parents also have similarly extreme values. Thus, we recommend the exclusion of such pairs from linkage studies. This recommendation reduces the required sample sizes by 3- to 28-fold. The degree of saving in the required sample sizes varies among different models and allele frequencies. The reduction is most dramatic (a 28-fold reduction) for a rare recessive gene. 5 refs., 6 tabs.

  7. A sib-pair approach to interval mapping a quantitative trait loci

    SciTech Connect

    Fulker, K.W. ); Cardon, L.R. )

    1994-06-01

    An interval mapping procedure based on the sib-pair method of Haseman and Elston is developed, and simulation studies are carried out to explore its properties. The procedure is analogous to other interval mapping procedures used with experimental material, such as plants and animals, and yields very similar results in terms of the location and effects size of a quantitative trait locus (QTL). The procedure offers an advantage over the conventional Haseman and Elston approach, in terms of power, and provides useful information concerning the location of a QTL. Because of its simplicity, the method readily lends itself to the analysis of selected samples for increased power and the evaluation of multilocus models of complex phenotypes. 26 refs., 4 figs., 5 tabs.

  8. Path analytic, sib-pair linkage and co-twin control studies of asthma and atopy

    SciTech Connect

    Duffy, D.L.; Healey, S.C.; Martin, N.G.

    1994-09-01

    Asthma and atopy are complex traits with multifactorial determinants, and require appropriate choice of phenotypes and analyses, including a linkage analysis of the putative 11q atopy locus. Participants in a large registry-based twin study of asthma were invited to take part in clinical testing. A total of 863 individuals including 419 complete twin pairs (where one or both members reported a history of wheeze) underwent histamine inhalation challenge, allergen skin prick testing, and venesection. Total serum immunoglobulin E (IgE) and bronchial responsiveness (BR) to histamine were highest in those who had wheezed most recently, and whose skin tests demonstrated allergy to house dust mite, cockroach, and rye grass. In ascertainment-corrected path analyses (FISHER), the heritability of IgE and BR were both 60%. Monozygotic (MZ) co-twin control analyses suggested house dust mite sensitization was the single strongest environmentally controlled risk factor for wheeze, while path analyses suggested genetic determination. In dizygotic (DZ) co-twin control analyses, sensitization to grasses was also an important predictor, suggesting pollinosis to be genetically correlated with wheezing, rather than causative. Multivariate path analyses suggested separate (correlated) genetic factors for BR, IgE, and allergy to house dust mite. A sib-pair (Haseman-Elston) linkage analysis of 220 DZ twin pairs did not support linkage to the high-affinity IgE receptor beta-subunit gene on 11q13 of atopy or BR. More recent linkage analyses that include parental genotyping will also be discussed. We conclude that the atopic phenotype consists of a number of traits with specific genetic allergens. Exposure to particular allergens can then cause specific outcomes, such as asthma.

  9. Neuropsychological and dimensional behavioral trait profiles in Costa Rican ADHD sib pairs: Potential intermediate phenotypes for genetic studies.

    PubMed

    Peskin, Viviana A; Ordóñez, Anna; Mackin, R Scott; Delucchi, Kevin; Monge, Silvia; McGough, James J; Chavira, Denise A; Berrocal, Monica; Cheung, Erika; Fournier, Eduardo; Badner, Judith A; Herrera, Luis Diego; Mathews, Carol A

    2015-06-01

    Attention deficit hyperactivity disorder (ADHD) is associated with substantial functional impairment in children and in adults. Many individuals with ADHD have clear neurocognitive deficits, including problems with visual attention, processing speed, and set shifting. ADHD is etiologically complex, and although genetic factors play a role in its development, much of the genetic contribution to ADHD remains unidentified. We conducted clinical and neuropsychological assessments of 294 individuals (269 with ADHD) from 163 families (48 multigenerational families created using genealogical reconstruction, 78 affected sib pair families, and 37 trios) from the Central Valley of Costa Rica (CVCR). We used principal components analysis (PCA) to group neurocognitive and behavioral variables using the subscales of the Child Behavior Checklist (CBCL) and 15 neuropsychological measures, and created quantitative traits for heritability analyses. We identified seven cognitive and two behavioral domains. Individuals with ADHD were significantly more impaired than their unaffected siblings on most behavioral and cognitive domains. The verbal IQ domain had the highest heritability (92%), followed by auditory attention (87%), visual processing speed and problem solving (85%), and externalizing symptoms (81%). The quantitative traits identified here have high heritabilities, similar to the reported heritability of ADHD (70-90%), and may represent appropriate alternative phenotypes for genetic studies. The use of multigenerational families from a genetically isolated population may facilitate the identification of ADHD risk genes in the face of phenotypic and genetic heterogeneity. PMID:25832558

  10. Neuropsychological and Dimensional Behavioral Trait Profiles in Costa Rican ADHD Sib Pairs: Potential Intermediate Phenotypes for Genetic Studies

    PubMed Central

    Peskin, Viviana A.; Ordóñez, Anna; Mackin, R. Scott; Delucchi, Kevin; Monge, Silvia; McGough, James J.; Chavira, Denise A.; Berrocal, Monica; Cheung, Erika; Fournier, Eduardo; Badner, Judith A.; Herrera, Luis Diego; Mathews, Carol A.

    2015-01-01

    Introduction Attention deficit hyperactivity disorder (ADHD) is associated with substantial functional impairment in children and in adults. Many individuals with ADHD have clear neurocognitive deficits, including problems with visual attention, processing speed, and set shifting. ADHD is etiologically complex, and although genetic factors play a role in its development, much of the genetic contribution to ADHD remains unidentified. Methods We conducted clinical and neuropsychological assessments of 294 individuals (269 with ADHD) from 163 families (48 multigenerational families created using genealogical reconstruction, 78 affected sib pair families, and 37 trios) from the Central Valley of Costa Rica (CVCR). We used principal components analysis (PCA) to group neurocognitive and behavioral variables using the subscales of the Child Behavior Checklist (CBCL) and 15 neuropsychological measures, and created quantitative traits for heritability analyses. Results We identified seven cognitive and two behavioral domains. Individuals with ADHD were significantly more impaired than their unaffected siblings on most behavioral and cognitive domains. The verbal IQ domain had the highest heritability (92%), followed by auditory attention (87%), visual processing speed and problem solving (85%), and externalizing symptoms (81%). Conclusions The quantitative traits identified here have high heritabilities, similar to the reported heritability of ADHD (70–90%), and may represent appropriate alternative phenotypes for genetic studies. The use of multigenerational families from a genetically isolated population may facilitate the identification of ADHD risk genes in the face of phenotypic and genetic heterogeneity. PMID:25832558

  11. A nonparametric regression-based linkage scan of rheumatoid factor-IgM using sib-pair squared sums and differences

    PubMed Central

    Ghosh, Saurabh; Rao, P Samba Siva; De, Gourab; Majumder, Partha P

    2007-01-01

    Parametric linkage methods for quantitative trait locus mapping require explicit specification of the probability model of the quantitative trait and hence can lead to misleading linkage inferences when the model assumptions are not valid. Ghosh and Majumder developed a nonparametric regression method based on kernel-smoothing for linkage mapping of quantitative trait locus using squared differences in trait values of independent sib pairs, which is relatively more robust than parametric methods with respect to violations in distributional assumptions. In this study, we modify the above mentioned nonparametric regression method by considering local linear polynomials instead of the Nadaraya-Watson estimator and squared sums of sib-pair trait values in addition to squared differences to perform a genome-wide scan of rheumatoid factor-IgM levels on sib pairs in the Genetic Analysis Workshop 15 simulated data set. We obtain significant evidence of linkage very close to the quantitative trait locus controlling for RF-IgM. We find that the simultaneous use of squared differences and squared sums increases the power to detect linkage compared to using only squared differences. However, because of all the sib pairs are selected for rheumatoid arthritis, there is reduced variance of RF-IgM values, and empirical power to detect linkage is not very high. We also compare the performance of our method with two linear regression approaches: the classical Haseman-Elston method using squared sib-pair trait differences and its extension proposed by Elston et al. using mean-corrected sib-pair cross-products. We find that the proposed nonparametric method yields more power than the linear regression approaches. PMID:18466603

  12. A genome-wide sib-pair scan for quantitative language traits reveals linkage to chromosomes 10 and 13

    PubMed Central

    Evans, P. D.; Mueller, K. L.; Gamazon, E. R.; Cox, N. J.; Tomblin, J. B.

    2016-01-01

    Although there is considerable evidence that individual differences in language development are highly heritable, there have been few genome-wide scans to locate genes associated with the trait. Previous analyses of language impairment have yielded replicable evidence for linkage to regions on chromosomes 16q, 19q, 13q (within lab) and at 13q (between labs). Here we report the first linkage study to screen the continuum of language ability, from normal to disordered, as found in the general population. 383 children from 147 sib-ships (214 sib-pairs) were genotyped on the Illumina® Linkage IVb Marker Panel using three composite language-related phenotypes and a measure of phonological memory (PM). Two regions (10q23.33; 13q33.3) yielded genome-wide significant peaks for linkage with PM. A peak suggestive of linkage was also found at 17q12 for the overall language composite. This study presents two novel genetic loci for the study of language development and disorders, but fails to replicate findings by previous groups. Possible reasons for this are discussed. PMID:25997078

  13. 21-hydroxylase deficiency families with HLA identical affected and unaffected sibs.

    PubMed Central

    Sinnott, P J; Dyer, P A; Price, D A; Harris, R; Strachan, T

    1989-01-01

    During our investigations of polymorphisms at, and in the immediate chromosomal vicinity of, the 21-hydroxylase locus in families with 21-hydroxylase deficiency, three families were found to show marked discordance in clinical features of HLA identical subjects. In one family, there is discordance between a boy with the simple virilising form of 21-hydroxylase deficiency and his two younger sisters, who are both HLA identical to their brother, but who have additional salt wasting features. In the other two families, one subject is severely affected and has very high 17-hydroxyprogesterone levels, but has an HLA identical sib who is asymptomatic and shows only slightly raised 17-hydroxyprogesterone levels. In all cases, HLA identity, as indicated by protein polymorphism studies (HLA-A, B, DR, C4A, C4B, and Bf typing), has been verified at the gene organisation level using 21-hydroxylase and complement C4 DNA probes. An HLA-Bw47 bearing haplotype in one of the latter families has not been transmitted to the affected child and appears to carry a normal 21-OHB allele and two genes which specify C4A allotypes. Images PMID:2783976

  14. Application of discordant sib-pair linkage analysis for mapping minor histocompatibility antigen loci in a novel graft-vs-host-disease model.

    PubMed

    Araki, J; Ohashi, J; Muramatsu, M

    2004-09-01

    Graft-vs-host disease (GVHD) is an adverse effect of allogenic bone marrow transplantation. Although a major cause of GVHD following bone marrow transplantation is incompatibility of major histocompatibility antigen (human leukocyte antigen, HLA) in donor-recipient pairs, the incompatibility of minor histocompatibility antigen (mHa) is known as another cause, especially in HLA-matched donor-recipient pairs. In 1998, Lunetta and Rogus proposed the use of discordant sib-pair (DSP) linkage analysis for detecting mHa and calculated the statistical power using the GVHD model, assuming single mHa locus with multiple alleles. Recently, we proposed a different GVHD model, assuming multiple mHa loci with two alleles (biallelic), considering the single-nucleotide polymorphisms. When the effect of each mHa locus on the occurrence of GVHD is independent, the possible triangle for DSP proposed by Lunetta and Rogus is not optimum, but a new possible triangle, named here as GVHD region, is needed. We evaluated, based on Monte Carlo simulation, the test criteria [log of odds (lod) score cutoffs] and power of DSP using the GVHD region for various parameter sets. The GVHD region showed a higher power than the DSP and entire regions in plausible situations. Our results suggest that the application of GVHD region to DSP is effective for the screening of mHa loci. PMID:15304004

  15. The distribution of genome shared identical by descent for a pair of full sibs by means of the continuous time Markov chain

    NASA Astrophysics Data System (ADS)

    Julie, Hongki; Pasaribu, Udjianna S.; Pancoro, Adi

    2015-12-01

    This paper will allow Markov Chain's application in genome shared identical by descent by two individual at full sibs model. The full sibs model was a continuous time Markov Chain with three state. In the full sibs model, we look for the cumulative distribution function of the number of sub segment which have 2 IBD haplotypes from a segment of the chromosome which the length is t Morgan and the cumulative distribution function of the number of sub segment which have at least 1 IBD haplotypes from a segment of the chromosome which the length is t Morgan. This cumulative distribution function will be developed by the moment generating function.

  16. Infantile refsum disease in four Amish sibs.

    PubMed

    Bader, P I; Dougherty, S; Cangany, N; Raymond, G; Jackson, C E

    2000-01-17

    Infantile Refsum disease (IRD) appears with varying degrees of impaired vision, hearing loss, developmental delays, and neuromotor deficiencies. We report on four Amish sibs with IRD from a consanguineous marriage; biochemical testing supported the diagnosis of IRD. Of particular interest in this sibship are characteristic poorly formed yellow-orange teeth in at least three of the four affected sibs and behavior problems in the affected females. PMID:10607947

  17. Image-Word Pairing-Congruity Effect on Affective Responses

    NASA Astrophysics Data System (ADS)

    Sanabria Z., Jorge C.; Cho, Youngil; Sambai, Ami; Yamanaka, Toshimasa

    The present study explores the effects of familiarity on affective responses (pleasure and arousal) to Japanese ad elements, based on the schema incongruity theory. Print ads showing natural scenes (landscapes) were used to create the stimuli (images and words). An empirical study was conducted to measure subjects' affective responses to image-word combinations that varied in terms of incongruity. The level of incongruity was based on familiarity levels, and was statistically determined by a variable called ‘pairing-congruity status’. The tested hypothesis proposed that even highly familiar image-word combinations, when combined incongruously, would elicit strong affective responses. Subjects assessed the stimuli using bipolar scales. The study was effective in tracing interactions between familiarity, pleasure and arousal, although the incongruous image-word combinations did not elicit the predicted strong effects on pleasure and arousal. The results suggest a need for further research incorporating kansei (i.e., creativity) into the process of stimuli selection.

  18. Familial Clustering of Executive Functioning in Affected Sibling Pair Families with ADHD

    ERIC Educational Resources Information Center

    Slaats-Willemse, Dorine; Swaab-Barneveld, Hanna; De Sonneville, Leo; Buitelaar, Jan

    2005-01-01

    Objective: To investigate familial clustering of executive functioning (i.e., response inhibition, fine visuomotor functioning, and attentional control) in attention-deficit/hyperactivity disorder (ADHD)-affected sibling pairs. Method: Fifty-two affected sibling pairs aged 6 to 18 years and diagnosed with ADHD according to DSM-IV performed the…

  19. Identification of Mendelian inconsistencies between SNP and pedigree information of sibs

    PubMed Central

    2011-01-01

    Background Using SNP genotypes to apply genomic selection in breeding programs is becoming common practice. Tools to edit and check the quality of genotype data are required. Checking for Mendelian inconsistencies makes it possible to identify animals for which pedigree information and genotype information are not in agreement. Methods Straightforward tests to detect Mendelian inconsistencies exist that count the number of opposing homozygous marker (e.g. SNP) genotypes between parent and offspring (PAR-OFF). Here, we develop two tests to identify Mendelian inconsistencies between sibs. The first test counts SNP with opposing homozygous genotypes between sib pairs (SIBCOUNT). The second test compares pedigree and SNP-based relationships (SIBREL). All tests iteratively remove animals based on decreasing numbers of inconsistent parents and offspring or sibs. The PAR-OFF test, followed by either SIB test, was applied to a dataset comprising 2,078 genotyped cows and 211 genotyped sires. Theoretical expectations for distributions of test statistics of all three tests were calculated and compared to empirically derived values. Type I and II error rates were calculated after applying the tests to the edited data, while Mendelian inconsistencies were introduced by permuting pedigree against genotype data for various proportions of animals. Results Both SIB tests identified animal pairs for which pedigree and genomic relationships could be considered as inconsistent by visual inspection of a scatter plot of pairwise pedigree and SNP-based relationships. After removal of 235 animals with the PAR-OFF test, SIBCOUNT (SIBREL) identified 18 (22) additional inconsistent animals. Seventeen animals were identified by both methods. The numbers of incorrectly deleted animals (Type I error), were equally low for both methods, while the numbers of incorrectly non-deleted animals (Type II error), were considerably higher for SIBREL compared to SIBCOUNT. Conclusions Tests to remove

  20. New support for an old hypothesis: density affects extra-pair paternity

    PubMed Central

    Mayer, Christian; Pasinelli, Gilberto

    2013-01-01

    Density has been suggested to affect variation in extra-pair paternity (EPP) in avian mating systems, because increasing density promotes encounter rates and thus mating opportunities. However, the significance of density affecting EPP variation in intra- and interspecific comparisons has remained controversial, with more support from intraspecific comparisons. Neither experimental nor empirical studies have consistently provided support for the density hypothesis. Testing the density hypothesis is challenging because density measures may not necessarily reflect extra-pair mating opportunities, mate guarding efforts may covary with density, populations studied may differ in migratory behavior and/or climatic conditions, and variation in density may be insufficient. Accounting for these potentially confounding factors, we tested whether EPP rates within and among subpopulations of the reed bunting (Emberiza schoeniclus) were related to density. Our analyses were based on data from 13 subpopulations studied over 4 years. Overall, 56.4% of totally 181 broods contained at least one extra-pair young (EPY) and 37.1% of totally 669 young were of extra-pair origin. Roughly 90% of the extra-pair fathers were from the adjacent territory or from the territory after the next one. Within subpopulations, the proportion of EPY in broods was positively related to local breeding density. Similarly, among subpopulations, proportion of EPY was positively associated with population density. EPP was absent in subpopulations consisting of single breeding pairs, that is, without extra-pair mating opportunities. Our study confirms that density is an important biological factor, which significantly influences the amount of EPP within and among subpopulations, but also suggests that other mechanisms influence EPP beyond the variation explained by density. PMID:23533071

  1. Multipoint Linkage Analysis of the Pseudoautosomal Regions, Using Affected Sibling Pairs

    PubMed Central

    Dupuis, Josée; Van Eerdewegh, Paul

    2000-01-01

    Affected sibling pairs are often the design of choice in linkage-analysis studies with the goal of identifying the genes that increase susceptibility to complex diseases. Methods for multipoint analysis based on sibling amount of sharing that is identical by descent are widely available, for both autosomal and X-linked markers. Such methods have the advantage of making few assumptions about the mode of inheritance of the disease. However, with this approach, data from the pseudoautosomal regions on the X chromosome pose special challenges. Same-sex sibling pairs will share, in that region of the genome, more genetic material identical by descent, with and without the presence of a disease-susceptibility gene. This increased sharing will be more pronounced for markers closely linked to the sex-specific region. For the same reason, opposite-sex sibling pairs will share fewer alleles identical by descent. Failure to take this inequality in sharing into account may result in a false declaration of linkage if the study sample contains an excess of sex-concordant pairs, or a linkage may be missed when an excess of sex-discordant pairs is present. We propose a method to take into account this expected increase/decrease in sharing when markers in the pseudoautosomal region are analyzed. For quantitative traits, we demonstrate, using the Haseman-Elston method, (1) the same inflation in type I error, in the absence of an appropriate correction, and (2) the inadequacy of permutation tests to estimate levels of significance when all phenotypic values are permuted, irrespective of gender. The proposed method is illustrated with a genome screen on 350 sibling pairs affected with type I diabetes. PMID:10869236

  2. Congenital familial myasthenic syndromes: disease and course in an affected dizygotic twin pair

    PubMed Central

    Pavone, Piero; Praticò, Andrea Domenico; Pavone, Vito; Falsaperla, Raffaele

    2013-01-01

    The present report describes clinical variability in an affected dizygotic twin pair. Twin 1 showed classical features of the congenital myasthenic syndromes (CMS), that is, ptosis, dysphonia, asthenia and hypotonia. In twin 2, these clinical signs were less pronounced, but subtle resulting in severe lumbar hyperlordosis. Molecular analysis, performed for both twins, revealed the presence of three polymorphisms in the heterozygous form in RAPSN gene. The present report highlights the clinical variability of the CMS. PMID:23365176

  3. How Does Guanine-Cytosine Base Pair Affect Excess-Electron Transfer in DNA?

    PubMed

    Lin, Shih-Hsun; Fujitsuka, Mamoru; Majima, Tetsuro

    2015-06-25

    Charge transfer and proton transfer in DNA have attracted wide attention due to their relevance in biological processes and so on. Especially, excess-electron transfer (EET) in DNA has strong relation to DNA repair. However, our understanding on EET in DNA still remains limited. Herein, by using a strongly electron-donating photosensitizer, trimer of 3,4-ethylenedioxythiophene (3E), and an electron acceptor, diphenylacetylene (DPA), two series of functionalized DNA oligomers were synthesized for investigation of EET dynamics in DNA. The transient absorption measurements during femtosecond laser flash photolysis showed that guanine:cytosine (G:C) base pair affects EET dynamics in DNA by two possible mechanisms: the excess-electron quenching by proton transfer with the complementary G after formation of C(•-) and the EET hindrance by inserting a G:C base pair as a potential barrier in consecutive thymines (T's). In the present paper, we provided useful information based on the direct kinetic measurements, which allowed us to discuss EET through oligonucleotides for the investigation of DNA damage/repair. PMID:26042867

  4. Occurrence of the Cys311 DRD2 variant in a pedigree multiply affected with panic disorder

    SciTech Connect

    Crawford, F.; Hoyne, J.; Diaz, P.

    1995-08-14

    Following the detection of the rare DRD2 codon 311 variant (Ser{yields}Cys) in an affected member from a large, multiply affected panic disorder family, we investigated the occurrence of this variant in other family members. The variant occurred in both affected and unaffected individuals. Further screening in panic disorder sib pairs unrelated to this family failed to detect the Cys311 variant. Our data suggests that this variant has no pathogenic role in panic disorder. 18 refs., 1 fig.

  5. ExPASy: SIB bioinformatics resource portal

    PubMed Central

    Artimo, Panu; Jonnalagedda, Manohar; Arnold, Konstantin; Baratin, Delphine; Csardi, Gabor; de Castro, Edouard; Duvaud, Séverine; Flegel, Volker; Fortier, Arnaud; Gasteiger, Elisabeth; Grosdidier, Aurélien; Hernandez, Céline; Ioannidis, Vassilios; Kuznetsov, Dmitry; Liechti, Robin; Moretti, Sébastien; Mostaguir, Khaled; Redaschi, Nicole; Rossier, Grégoire; Xenarios, Ioannis; Stockinger, Heinz

    2012-01-01

    ExPASy (http://www.expasy.org) has worldwide reputation as one of the main bioinformatics resources for proteomics. It has now evolved, becoming an extensible and integrative portal accessing many scientific resources, databases and software tools in different areas of life sciences. Scientists can henceforth access seamlessly a wide range of resources in many different domains, such as proteomics, genomics, phylogeny/evolution, systems biology, population genetics, transcriptomics, etc. The individual resources (databases, web-based and downloadable software tools) are hosted in a ‘decentralized’ way by different groups of the SIB Swiss Institute of Bioinformatics and partner institutions. Specifically, a single web portal provides a common entry point to a wide range of resources developed and operated by different SIB groups and external institutions. The portal features a search function across ‘selected’ resources. Additionally, the availability and usage of resources are monitored. The portal is aimed for both expert users and people who are not familiar with a specific domain in life sciences. The new web interface provides, in particular, visual guidance for newcomers to ExPASy. PMID:22661580

  6. General kin selection models for genetic evolution of sib altruism in diploid and haplodiploid species.

    PubMed Central

    Levitt, P R

    1975-01-01

    A population genetic approach is presented for general analysis and comparison of kin selection models of sib and half-sib altruism. Nine models are described, each assuming a particular mode of inheritance, number of female inseminations, and Mendelian dominance of the altruist gene. In each model, the selective effects of altruism are described in terms of two general fitness functions, A(beta) and S(beta), giving respectively the expected fitness of an altruist and a nonaltruist as a function of the fraction of altruists beta in a given sibship. For each model, exact conditions are reported for stability at altruist and nonaltruist fixation. Under the Table 3 axions, the stability conditions may then be partially ordered on the basis of implications holding between pairs of conditions. The partial orderings are compared with predictions of the kin selection theory of Hamilton. PMID:1060136

  7. General kin selection models for genetic evolution of sib altruism in diploid and haplodiploid species.

    PubMed

    Levitt, P R

    1975-11-01

    A population genetic approach is presented for general analysis and comparison of kin selection models of sib and half-sib altruism. Nine models are described, each assuming a particular mode of inheritance, number of female inseminations, and Mendelian dominance of the altruist gene. In each model, the selective effects of altruism are described in terms of two general fitness functions, A(beta) and S(beta), giving respectively the expected fitness of an altruist and a nonaltruist as a function of the fraction of altruists beta in a given sibship. For each model, exact conditions are reported for stability at altruist and nonaltruist fixation. Under the Table 3 axions, the stability conditions may then be partially ordered on the basis of implications holding between pairs of conditions. The partial orderings are compared with predictions of the kin selection theory of Hamilton. PMID:1060136

  8. How Proficiency-Pairing Affects Students' Peer-Mediated Revisions of EFL Writing: Three Case Studies

    ERIC Educational Resources Information Center

    Wang, Weiqiang

    2015-01-01

    The present study reports on a teacher's classroom-based research into the influence of proficiency-pairing on students' peer-mediated draft revisions. Three students of an EFL writing course at a Chinese university, who formed into peer dyads with their classmates voluntarily, participated in the study. Throughout the EFL writing course, they…

  9. Juvenile social experience affects pairing success at adulthood: congruence with the loser effect?

    PubMed

    Mariette, Mylene M; Cathaud, Charlène; Chambon, Rémi; Vignal, Clémentine

    2013-09-22

    Social interactions with adults are often critical for the development of mating behaviours. However, the potential role of other primary social partners such as juvenile counterparts is rarely considered. Most interestingly, it is not known whether interactions with juvenile females improve males' courtship and whether, similar to the winner and loser effects in a fighting context--outcome of these interactions shapes males' behaviour in future encounters. We investigated the combined effects of male quality and juvenile social experience on pairing success at adulthood in zebra finches (Taeniopygia guttata). We manipulated brood size to alter male quality and then placed males in either same- or mixed-sex juvenile dyads until adulthood. We found that males from reduced broods obtained more copulations and males from mixed-sex dyads had more complete courtships. Furthermore, independent of their quality, males that failed to pair with juvenile females, but not juvenile males, had a lower pairing success at adulthood. Our study shows that negative social experience with peers during adolescence may be a potent determinant of pairing success that can override the effects of early environmental conditions on male attractiveness and thereby supports the occurrence of an analogous process to the loser effect in a mating context. PMID:23902911

  10. Contribution of lone-pairs to birefringence affected by the Pb(II) coordination environment: a DFT investigation.

    PubMed

    Jing, Qun; Yang, Zhihua; Pan, Shilie; Xue, Dongfeng

    2015-09-14

    Pb(II) cations have long been associated with lone-pairs which can help to enhance the optical anisotropic birefringence. In this paper, the contribution of lead cations to birefringence has been investigated using first-principles and real-space atom-cutting methods. The results show that the contribution of lead cations to birefringence is determined by the degree of stereochemical activity, which is affected by the coordination environment of lead cations. PMID:26234398

  11. Conditioned water affects pair formation behaviour in the marine polychaete Neanthes (Nereis) acuminata.

    PubMed

    Storey, Ellen J; Reish, Don J; Hardege, Jörg D

    2013-01-01

    Assessing cues from conspecifics is paramount during mate choice decisions. Neanthes acuminata is a marine polychaete with a unique life cycle: pair formation, female death following reproduction, male parental care and male ability to mate again after egg care. Males completing such egg care are 'experienced'. Females have been shown to prefer experienced males over all others, including aggressively dominant males. As the female dies following reproduction, the reproductive success of her offspring depends upon successful parental care by the male. It is therefore vital that the female makes a good mate choice decision. This paper shows that the use of conditioned water from males caring for eggs and newly experienced males caused the female to alter her choice to a previously undesired male. However, conditioned water from males, which had reproduced but were isolated for 2 weeks, did not have the same effect on pairing behaviour. This indicates that the smell of experience is short lived. PMID:22941305

  12. Coulomb blockade and incoherent tunneling of Cooper pairs in ultrasmall junctions affected by strong quantum fluctuations

    NASA Astrophysics Data System (ADS)

    Kuzmin, L. S.; Nazarov, Yu. V.; Haviland, D. B.; Delsing, P.; Claeson, T.

    1991-08-01

    We have fabricated and investigated submicron-size (0.01 and 0.04 μm2) Pb-alloy single Josephson junctions attached to high-resistance thin-film NiCr or Cr leads which provide the necessary conditions for a strong charging effect. When the Josephson coupling energy is less than the charging energy, we find a novel shape of the current-voltage curves, with a Coulomb gap at small voltages, and a current peak at larger voltages. A theory based on the concept of incoherent Cooper-pair tunneling has explained the data well.

  13. Affecteds-only linkage methods are not a panacea

    SciTech Connect

    Greenberg, D.A.; Hodge, S.E. |; Vieland, V.J.; Spence, M.A.

    1996-04-01

    Affected-sib-pair (ASP) methods and their variations, such as the affected-pedigree-member (APM) method, have become preferred methods of analysis. Three reasons are usually given as the advantages of ASP/APM methods over LOD-score analysis (likelihood-maximization techniques). First, the most frequently cited is that ASP/APM analysis is non-parametric, whereas LOD-score analysis requires specification of a genetic model. A related consideration is that penetrance is not a confounding factor in ASP/APM analysis, as it is with LOD scores. Second, ASP/APM methods require the collection of data from only a limited number of family members - and, presumably, from those most motivated to help research in the disease, i.e., those affected. A third reason concerns the ease and intuitive appeal of the theory and calculations. Sib-pair analysis is easily understood and can be done on the {open_quotes}back of the envelope.{close_quotes} Except for the more sophisticated ASP methods, one need only count the numbers of sibs sharing no, one, or two alleles in common and apply conventional statistics, to get an answer (although APM methods do require more sophisticated analysis). LOD-score analysis, on the other hand, appears more complex, requiring likelihood maximization, computers and sophisticated programs, and the assumption of a mode of inheritance. 32 refs.

  14. Linkage of the VNTR/insulin-gene and type I diabetes mellitus: Increased gene sharing in affected sibling pairs

    SciTech Connect

    Owerbach, D.; Gabbay, K.H. )

    1994-05-01

    Ninety-six multiplex type I diabetic families were typed at the 5' flanking region of the insulin gene by using a PCR assay that better resolves the VNTR into multiple alleles. Affected sibling pairs shared 2, 1, and 0 VNTR alleles - identical by descent - at a frequency of .47, .45, and .08, respectively, a ratio that deviated from the expected 1:2:1 ratio (P<.001). These results confirm linkage of the chromosome 11p15.5 region with type I diabetes mellitus susceptibility. 20 refs., 2 tabs.

  15. SIB-DOTA: A trifunctional prosthetic group potentially amenable for multi-modal labeling that enhances tumor uptake of internalizing monoclonal antibodies

    PubMed Central

    Vaidyanathan, G.; White, B. J.; Affleck, D.J.; Zhao, X.G.; Welsh, P.C.; McDougald, D.; Choi, J.; Zalutsky, M. R.

    2012-01-01

    A major drawback of internalizing monoclonal antibodies (mAbs) radioiodinated with direct electrophilic approaches is that tumor retention of radioactivity is compromised by the rapid washout of iodo-tyrosine, the primary labeled catabolite for mAbs labeled via this strategy. In our continuing efforts to develop more versatile residualizing labels that could overcome this problem, we have designed SIB-DOTA, a prosthetic labeling template that combines the features of the prototypical, dehalogenation resistant N-succinimidyl 3-iodobenzoate (SIB) with DOTA, a useful macrocyclic chelator for labeling with radiometals. Herein we describe the synthesis of the unlabeled standard of this prosthetic moiety, its protected tin precursor, and radioiodinated SIB-DOTA. An anti-EGFRvIII-reactive mAb, L8A4 was radiolabeled with [131I]SIB-DOTA in 27.1 ± 6.2% (n = 2) conjugation yields and its targeting properties to the same mAb labeled with [125I]SGMIB both in vitro and in vivo using U87MG·ΔEGFR cells and xenografts were compared. In vitro paired-label internalization assays showed that the intracellular radioactivity from [131I]SIB-DOTA-L8A4 was 21.4 ± 0.5% and 26.2 ± 1.1% of initially bound radioactivity at 16 and 24 h, respectively. In comparison, these values for [125I]SGMIB-L8A4 were 16.7 ± 0.5% and 14.9 ± 1.1%. Similarly, the SIB-DOTA prosthetic group provided better tumor targeting in vivo than SGMIB over 8 d period. These results suggest that SIB-DOTA warrants further evaluation as a residualizing agent for labeling internalizing mAbs including those targeted to EGFRvIII. PMID:23159039

  16. Genomic selection in a pig population including information from slaughtered full sibs of boars within a sib-testing program.

    PubMed

    Samorè, A B; Buttazzoni, L; Gallo, M; Russo, V; Fontanesi, L

    2015-05-01

    Genomic selection is becoming a common practise in dairy cattle, but only few works have studied its introduction in pig selection programs. Results described for this species are highly dependent on the considered traits and the specific population structure. This paper aims to simulate the impact of genomic selection in a pig population with a training cohort of performance-tested and slaughtered full sibs. This population is selected for performance, carcass and meat quality traits by full-sib testing of boars. Data were simulated using a forward-in-time simulation process that modeled around 60K single nucleotide polymorphisms and several quantitative trait loci distributed across the 18 porcine autosomes. Data were edited to obtain, for each cycle, 200 sires mated with 800 dams to produce 800 litters of 4 piglets each, two males and two females (needed for the sib test), for a total of 3200 newborns. At each cycle, a subset of 200 litters were sib tested, and 60 boars and 160 sows were selected to replace the same number of culled male and female parents. Simulated selection of boars based on performance test data of their full sibs (one castrated brother and two sisters per boar in 200 litters) lasted for 15 cycles. Genotyping and phenotyping of the three tested sibs (training population) and genotyping of the candidate boars (prediction population) were assumed. Breeding values were calculated for traits with two heritability levels (h 2=0.40, carcass traits, and h 2=0.10, meat quality parameters) on simulated pedigrees, phenotypes and genotypes. Genomic breeding values, estimated by various models (GBLUP from raw phenotype or using breeding values and single-step models), were compared with the classical BLUP Animal Model predictions in terms of predictive ability. Results obtained for traits with moderate heritability (h 2=0.40), similar to the heritability of traits commonly measured within a sib-testing program, did not show any benefit from the

  17. Superconducting state in (W, Ta)5SiB2

    NASA Astrophysics Data System (ADS)

    Fukuma, M.; Kawashima, K.; Akimitsu, J.

    We characterize the superconducting state in a boro-silicide (W, Ta)5SiB2, with Tc of 6.5 K by means of magnetization, electrical resistivity, and specific heat measurements. As x increased, the transition temperature Tc abruptly enhances from 5.8 to 6.5 K. The magnetization versus magnetic field (M-H) curve indicated that (W, Ta)5SiB2 was a conventional type-II superconductor. The estimated lower critical field Hc1(0) and upper critical field Hc2(T) are about 121 Oe and 14.7 kOe, respectively. The penetration depth λ(0) and coherence length ξ(0) are calculated to be approximately 369 and 14.9 nm, respectively, using Ginzburg-Landau (GL) equations. Specific heat data shows the superconductivity in W4.5Ta0.5SiB2 belongs to a week-coupling BCS superconductor. Finally, we discuss the increasing of Tc in of (W, Ta)5SiB2 system.

  18. A large phenotypic sib-sib discordance for the Rh blood system. A possible new feto-maternal compatibility system.

    PubMed Central

    Valenzuela, C Y; Harb, Z; Avendaño, A; Acuña, M P

    1982-01-01

    A large sib-sib phenotypic discordance for the Rh system has been found in a longitudinal follow-up study on growth and development. Sibs born no more than 3 years later than their respective indexes show a significant tendency to have a different phenotype from that of their indexes. The hypothesis that distortion is due to eggs or fetal loss finds support in the existence of increased time intervals between indexes' and sibs' births in those cases in which the losses were suspected. Two groups of index families made according to the presence or absence of the cde haplotype in their genotype show important differences in segregation and reproductive patterns. The observed distortions cannot be explained by the differences in known antigenic Rh specificities. The existence of a new feto-maternal compatibility system would better fit these facts and would also allow the reinterpretation of several distortions associated with Rh described in the literature that have never been satisfactorily explained. PMID:6808831

  19. Evaluation of Factors Affecting Continuous Performance Test Identical Pairs Version Score of Schizophrenic Patients in a Japanese Clinical Sample

    PubMed Central

    Koide, Takayoshi; Aleksic, Branko; Kikuchi, Tsutomu; Banno, Masahiro; Kohmura, Kunihiro; Adachi, Yasunori; Kawano, Naoko; Iidaka, Tetsuya; Ozaki, Norio

    2012-01-01

    Aim. Cognitive impairment in schizophrenia strongly relates to social outcome and is a good candidate for endophenotypes. When we accurately measure drug efficacy or effects of genes or variants relevant to schizophrenia on cognitive impairment, clinical factors that can affect scores on cognitive tests, such as age and severity of symptoms, should be considered. To elucidate the effect of clinical factors, we conducted multiple regression analysis using scores of the Continuous Performance Test Identical Pairs Version (CPT-IP), which is often used to measure attention/vigilance in schizophrenia. Methods. We conducted the CPT-IP (4-4 digit) and examined clinical information (sex, age, education years, onset age, duration of illness, chlorpromazine-equivalent dose, and Positive and Negative Symptom Scale (PANSS) scores) in 126 schizophrenia patients in Japanese population. Multiple regression analysis was used to evaluate the effect of clinical factors. Results. Age, chlorpromazine-equivalent dose, and PANSS-negative symptom score were associated with mean d′ score in patients. These three clinical factors explained about 28% of the variance in mean d′ score. Conclusions. As conclusion, CPT-IP score in schizophrenia patients is influenced by age, chlorpromazine-equivalent dose and PANSS negative symptom score. PMID:22966454

  20. Two male sibs with severe micrognathia and a missense variant in MED12.

    PubMed

    Prescott, Trine E; Kulseth, Mari Ann; Heimdal, Ketil R; Stadheim, Barbro; Hopp, Einar; Gambin, Tomasz; Coban Akdemir, Zeynep H; Jhangiani, Shalini N; Muzny, Donna M; Gibbs, Richard A; Lupski, James R; Stray-Pedersen, Asbjørg

    2016-08-01

    Missense variants in MED12 cause three partially overlapping dysmorphic X-linked intellectual disability (XLID) syndromes: Lujan-Fryns syndrome (also known as Lujan syndrome), FG syndrome (also known as Opitz-Kaveggia syndrome) and X-linked Ohdo syndrome. We report a family with two severely micrognathic male sibs, a 10½ year old boy and a fetus, in which hemizygosity for a previously unreported missense variant in exon 13 of MED12 (NM_005120.2), c.1862G > A, p.(Arg621Gln) was detected by whole exome sequencing. The affected sibs shared no other rare variant with relevance to the phenotype. X-chromosome inactivation in blood was completely skewed (100:0) in the unaffected heterozygous mother, most likely as a result of preferential inactivation of the X-chromosome harbouring the missense variant in MED12. Neither the unaffected brother nor the unaffected maternal grandfather carried the missense variant in MED12. In the 10½ year old boy, upper airway obstruction secondary to Pierre Robin sequence necessitated a tracheostomy for the first 10 months of life. He has mild to moderate intellectual disability and some dysmorphic features seen in MED12-related syndromes. In addition, he has a horizontal gaze paresis, anomalies of the inner ear, and a cervical block vertebra. This report contributes to the expanding phenotypic range associated with MED12-mutations. PMID:27286923

  1. Medical applications of poly(styrene-block-isobutylene-block-styrene) ("SIBS").

    PubMed

    Pinchuk, Leonard; Wilson, Gregory J; Barry, James J; Schoephoerster, Richard T; Parel, Jean-Marie; Kennedy, Joseph P

    2008-02-01

    Poly(Styrene-block-IsoButylene-block-Styrene) ("SIBS") is a biostable thermoplastic elastomer with physical properties that overlap silicone rubber and polyurethane. Initial data collected with SIBS stent-grafts and coatings on metallic stents demonstrate hemocompatibility, biocompatibility and long-term stability in contact with metal. SIBS has been used successfully as the carrier for a drug-eluting coronary stent; specifically Boston Scientific's TAXUS stent, and its uses are being investigated for ophthalmic implants to treat glaucoma, synthetic heart valves to possibly replace tissue valves and other applications. At present, researchers developing medical devices utilizing SIBS have found the following: (1) SIBS does not substantially activate platelets in the vascular system; (2) polymorphonuclear leukocytes in large numbers are not commonly observed around SIBS implants in the vascular system or in subcutaneous implants or in the eye; (3) myofibroblasts, scarring and encapsulation are not clinically significant with SIBS implanted in the eye; (4) embrittlement has not been observed in any implant location; (5) calcification within the polymer has not been observed; and (6) degradation has not been observed in any living system to date. Some deficiencies of SIBS that need to be addressed include creep deformation in certain load-bearing applications and certain sterilization requirements. The reason for the excellent biocompatibility of SIBS may be due to the inertness of SIBS and lack of cleavable moieties that could be chemotactic towards phagocytes. PMID:17980425

  2. Sibs with atopy and asthma share marker alleles at 11q13, but not at 7q31 or 14q32

    SciTech Connect

    Kate, L.P. ten; Collee, J.M.; Vries, H.G. de

    1994-09-01

    We studied allele sharing in 26 sib-pairs affected with atopy and asthma, recruited through a pediatric pulmonology department. Inclusion criteria were a positive score (2 symptoms or more) on a modified Dutch version of the MRC/ECCS questionnaire on respiratory symptoms and positive IgE tests (specific IgE 0.35 PRU/ml or more; total serum IgE for children under 10 years as described by Kjellmann et al., 1976; for older children 100 U/ml or over). Twenty-six sibpairs fulfilled these criteria. The microsatellites and polymorphic markers used in the analysis were 17bTA (an intragenic marker in the cystic fibrosis gene on 7q31); D11S534, D11S527, D11S97, PYGM, D11S480, Fc{epsilon}RI (all on 11q13, ordered from telomere to centromere) and D14S51 (a CA repeat close to the {alpha}-1-antitrypsin gene). We observed no sharing with the markers on 7q31 and 14q32, but significant sharing with markers on chromosome 11q13, especially D11S97, PYGM and D11S480. Sharing patterns were consistent with the existence of a dominant gene involved in the pathogenesis of atopic asthma on chromosome 11.

  3. Fifteen years SIB Swiss Institute of Bioinformatics: life science databases, tools and support.

    PubMed

    Stockinger, Heinz; Altenhoff, Adrian M; Arnold, Konstantin; Bairoch, Amos; Bastian, Frederic; Bergmann, Sven; Bougueleret, Lydie; Bucher, Philipp; Delorenzi, Mauro; Lane, Lydie; Le Mercier, Philippe; Lisacek, Frédérique; Michielin, Olivier; Palagi, Patricia M; Rougemont, Jacques; Schwede, Torsten; von Mering, Christian; van Nimwegen, Erik; Walther, Daniel; Xenarios, Ioannis; Zavolan, Mihaela; Zdobnov, Evgeny M; Zoete, Vincent; Appel, Ron D

    2014-07-01

    The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) was created in 1998 as an institution to foster excellence in bioinformatics. It is renowned worldwide for its databases and software tools, such as UniProtKB/Swiss-Prot, PROSITE, SWISS-MODEL, STRING, etc, that are all accessible on ExPASy.org, SIB's Bioinformatics Resource Portal. This article provides an overview of the scientific and training resources SIB has consistently been offering to the life science community for more than 15 years. PMID:24792157

  4. Fifteen years SIB Swiss Institute of Bioinformatics: life science databases, tools and support

    PubMed Central

    Stockinger, Heinz; Altenhoff, Adrian M.; Arnold, Konstantin; Bairoch, Amos; Bastian, Frederic; Bergmann, Sven; Bougueleret, Lydie; Bucher, Philipp; Delorenzi, Mauro; Lane, Lydie; Mercier, Philippe Le; Lisacek, Frédérique; Michielin, Olivier; Palagi, Patricia M.; Rougemont, Jacques; Schwede, Torsten; von Mering, Christian; van Nimwegen, Erik; Walther, Daniel; Xenarios, Ioannis; Zavolan, Mihaela; Zdobnov, Evgeny M.; Zoete, Vincent; Appel, Ron D.

    2014-01-01

    The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) was created in 1998 as an institution to foster excellence in bioinformatics. It is renowned worldwide for its databases and software tools, such as UniProtKB/Swiss-Prot, PROSITE, SWISS-MODEL, STRING, etc, that are all accessible on ExPASy.org, SIB's Bioinformatics Resource Portal. This article provides an overview of the scientific and training resources SIB has consistently been offering to the life science community for more than 15 years. PMID:24792157

  5. Inferring relationships between pairs of individuals from locus heterozygosities

    PubMed Central

    Presciuttini, Silvano; Toni, Chiara; Tempestini, Elena; Verdiani, Simonetta; Casarino, Lucia; Spinetti, Isabella; Stefano, Francesco De; Domenici, Ranieri; Bailey-Wilson, Joan E

    2002-01-01

    Background The traditional exact method for inferring relationships between individuals from genetic data is not easily applicable in all situations that may be encountered in several fields of applied genetics. This study describes an approach that gives affordable results and is easily applicable; it is based on the probabilities that two individuals share 0, 1 or both alleles at a locus identical by state. Results We show that these probabilities (zi) depend on locus heterozygosity (H), and are scarcely affected by variation of the distribution of allele frequencies. This allows us to obtain empirical curves relating zi's to H for a series of common relationships, so that the likelihood ratio of a pair of relationships between any two individuals, given their genotypes at a locus, is a function of a single parameter, H. Application to large samples of mother-child and full-sib pairs shows that the statistical power of this method to infer the correct relationship is not much lower than the exact method. Analysis of a large database of STR data proves that locus heterozygosity does not vary significantly among Caucasian populations, apart from special cases, so that the likelihood ratio of the more common relationships between pairs of individuals may be obtained by looking at tabulated zi values. Conclusions A simple method is provided, which may be used by any scientist with the help of a calculator or a spreadsheet to compute the likelihood ratios of common alternative relationships between pairs of individuals. PMID:12441003

  6. Infantile spinal muscular atrophy (SMA) and multiple congenital bone fractures in sibs: a lethal new syndrome.

    PubMed Central

    Borochowitz, Z; Glick, B; Blazer, S

    1991-01-01

    Acute infantile spinal muscular atrophy (SMA type I, Werdnig-Hoffmann disease) has generally been accepted as an autosomal recessive disorder. However, several investigators have noted a slightly increased male to female ratio. We describe here a family with two affected male sibs who had a form of acute infantile SMA with congenital bone fractures, whose parents were first cousins. Pedigree analysis strongly suggested autosomal recessive inheritance, but X linked recessive inheritance could not be ruled out. In view of the heterogeneity of the SMAs, and the distinct clinical features found in our patients, we suggest that their infantile SMA might well be a distinct entity. We suggest that SMA I with congenital contractures and bone fractures appears to be a recognisable disorder that can be distinguished from the more common classic form of SMA I. PMID:1865475

  7. The SIB Swiss Institute of Bioinformatics’ resources: focus on curated databases

    PubMed Central

    2016-01-01

    The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) provides world-class bioinformatics databases, software tools, services and training to the international life science community in academia and industry. These solutions allow life scientists to turn the exponentially growing amount of data into knowledge. Here, we provide an overview of SIB's resources and competence areas, with a strong focus on curated databases and SIB's most popular and widely used resources. In particular, SIB's Bioinformatics resource portal ExPASy features over 150 resources, including UniProtKB/Swiss-Prot, ENZYME, PROSITE, neXtProt, STRING, UniCarbKB, SugarBindDB, SwissRegulon, EPD, arrayMap, Bgee, SWISS-MODEL Repository, OMA, OrthoDB and other databases, which are briefly described in this article. PMID:26615188

  8. The SIB Swiss Institute of Bioinformatics' resources: focus on curated databases.

    PubMed

    2016-01-01

    The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) provides world-class bioinformatics databases, software tools, services and training to the international life science community in academia and industry. These solutions allow life scientists to turn the exponentially growing amount of data into knowledge. Here, we provide an overview of SIB's resources and competence areas, with a strong focus on curated databases and SIB's most popular and widely used resources. In particular, SIB's Bioinformatics resource portal ExPASy features over 150 resources, including UniProtKB/Swiss-Prot, ENZYME, PROSITE, neXtProt, STRING, UniCarbKB, SugarBindDB, SwissRegulon, EPD, arrayMap, Bgee, SWISS-MODEL Repository, OMA, OrthoDB and other databases, which are briefly described in this article. PMID:26615188

  9. Hurler-Scheie phenotype: a report of two pairs of inbred sibs.

    PubMed

    Kaibara, N; Eguchi, M; Shibata, K; Takagishi, K

    1979-01-01

    Four cases from two families with dermatan sulfate mucopolysacchariduria who lack alpha-L-iduronidase in peripheral leukocytes are described. The clinical and roentgenographic features of these cases represent an intermediate phenotype between Hurler's syndrome and Scheie's syndrome, and both parents in each family are first cousins. In the presence of parental consanguinity, a phenotypic variation or a third mutant allele at the iduronidase locus seems to be a more reasonable explanation for these cases than a genetic compound. PMID:119701

  10. Registration of Four Low-Phytate/Wild Type Pairs of Barley Germplasm.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four pairs of sib lines derived from low-phyate mutants have been developed and released in 2007 by The Agricultural Research Service, U.S. Department of Agriculture. Each pair consists of a low phytate (LP) and a wildtype (WT) line. These lines are designated LP1 (P.I. xxxxxx) and LP1-WT(P.I. xxxxx...

  11. SibRank: Signed bipartite network analysis for neighbor-based collaborative ranking

    NASA Astrophysics Data System (ADS)

    Shams, Bita; Haratizadeh, Saman

    2016-09-01

    Collaborative ranking is an emerging field of recommender systems that utilizes users' preference data rather than rating values. Unfortunately, neighbor-based collaborative ranking has gained little attention despite its more flexibility and justifiability. This paper proposes a novel framework, called SibRank that seeks to improve the state of the art neighbor-based collaborative ranking methods. SibRank represents users' preferences as a signed bipartite network, and finds similar users, through a novel personalized ranking algorithm in signed networks.

  12. A revised land surface parameterization (SiB2) for atmospheric GCMs. Part I: Model formulation

    SciTech Connect

    Sellers, P.J.; Collatz, G.J.

    1996-04-01

    The formulation of a revised land surface parameterization for use within atmospheric general circulation models (GCMs) is presented. The model (SiB2) incorporates several significant improvements over the first version of the Simple Biosphere model (SiB) described in Sellers et al. The improvements can be summarized as follows: (1) incorporation of a realistic canopy photosynthesis-conductance model to describe the simultaneous transfer of CO{sub 2} and water vapor into and out of the vegetation, respectively; (2) use of satellite data, as described in a companion paper, Part II, to describe the vegetation phenology; (3) modification of the hydrological submodel to give better descriptions of baseflows and a more reliable calculation of interlayer exchanges within the soil profile; (4) incorporation of a {open_quotes}patchy{close_quotes} snowmelt treatment, which prevents rapid thermal and surface reflectance transitions when the area-zveraged snow cover is low and decreasing. To accommodate the changes in (1) and (2) above, the original two-layer vegetation canopy structure of SiB1 has been reduced to a single layer in SiB2. The use of satellite data in SiB2 and the performance of SiB2 when coupled to a GCM are described in the two companion papers. 68 refs., 7 figs., 4 tabs.

  13. The Depression Network (DeNT) Study: methodology and sociodemographic characteristics of the first 470 affected sibling pairs from a large multi-site linkage genetic study

    PubMed Central

    Farmer, Anne; Breen, Gerome; Brewster, Shyama; Craddock, Nick; Gill, Mike; Korszun, Ania; Maier, Wolfgang; Middleton, Lefkos; Mors, Ole; Owen, Mike; Perry, Julia; Preisig, Martin; Rietschel, Marcella; Reich, Theodore; Jones, Lisa; Jones, Ian; McGuffin, Peter

    2004-01-01

    Background The Depression Network Study (DeNt) is a multicentre study designed to identify genes and/or loci linked to and/or associated with susceptibility to unipolar depression in Caucasian families. This study presents the method and socio-demographic details of the first 470 affected sibling pairs recruited from 8 different sites in Europe and the United States of America. Methods Probands fulfilling either the Diagnostic and Statistical Manual 4th edition (DSM-IV) or the International Classification of Diseases 10th edition (ICD-10) criteria for recurrent unipolar depression of moderate or severe degree and who had at least one similarly affected sibling were eligible for the study. Detailed clinical and psychological assessments were undertaken on all subjects including an interview using the Schedules for Clinical Assessment in Neuropsychiatry. Blood samples were collected from all participants to extract DNA for linkage analysis. Results The different sites used different recruitment strategies depending on local health care organisation but despite this there was remarkable similarity across sites for the subjects recruited. Although the Bonn site had significantly older subjects both for age of onset and age at interview, for the sample as a whole, subjects were interviewed in their mid-40s and had experienced the onset of their recurrent depression in their 20s. Preliminary genome screening was able to include 929 out of the 944 subjects (98.4%) typed at 932 autosomal and 544 X chromosome markers Conclusions This paper describes the methodology and the characteristics of the subjects from the 414 families included in the first wave of genotyping from the multi-site DeNT study. Ultimately the study aims to collect affected sibling pairs from approximately 1200 families. PMID:15588307

  14. Covariance Between Genotypic Effects and its Use for Genomic Inference in Half-Sib Families

    PubMed Central

    Wittenburg, Dörte; Teuscher, Friedrich; Klosa, Jan; Reinsch, Norbert

    2016-01-01

    In livestock, current statistical approaches utilize extensive molecular data, e.g., single nucleotide polymorphisms (SNPs), to improve the genetic evaluation of individuals. The number of model parameters increases with the number of SNPs, so the multicollinearity between covariates can affect the results obtained using whole genome regression methods. In this study, dependencies between SNPs due to linkage and linkage disequilibrium among the chromosome segments were explicitly considered in methods used to estimate the effects of SNPs. The population structure affects the extent of such dependencies, so the covariance among SNP genotypes was derived for half-sib families, which are typical in livestock populations. Conditional on the SNP haplotypes of the common parent (sire), the theoretical covariance was determined using the haplotype frequencies of the population from which the individual parent (dam) was derived. The resulting covariance matrix was included in a statistical model for a trait of interest, and this covariance matrix was then used to specify prior assumptions for SNP effects in a Bayesian framework. The approach was applied to one family in simulated scenarios (few and many quantitative trait loci) and using semireal data obtained from dairy cattle to identify genome segments that affect performance traits, as well as to investigate the impact on predictive ability. Compared with a method that does not explicitly consider any of the relationship among predictor variables, the accuracy of genetic value prediction was improved by 10–22%. The results show that the inclusion of dependence is particularly important for genomic inference based on small sample sizes. PMID:27402363

  15. Testing the Simple Biosphere Model (SiB) Using Point Micrometeorological and Biophysical Data.

    NASA Astrophysics Data System (ADS)

    Sellers, P. J.; Dorman, J. L.

    1987-05-01

    The Simple Biosphere model (SiB) of Sellers et al. (1986) was designed for use within General Circulation Models (GCMs) of the earth's atmosphere. The main objective of SiB is to provide a biophysically realistic description of those processes which control the transfer of radiation, sensible heat, latent heat and momentum between the terrestrial surface and the atmosphere. As a result, SiB is more complex and has a larger input parameter set than most equivalent formulations used in GCMs. Prior to implementing SiB in a GCM, it is essential that its components and its functioning as a whole, be thoroughly tested. Additionally, it is highly desirable that the model's response to errors or uncertainties in the input parameter set be explored. This paper discusses investigations that were directed at addressing then two issues.Micrometeorological and biophysical measurements from surface experiments conducted over arable crops in West Germany and the United States and a forested site in the United Kingdom were used to test the operation of SiB. Observed values of the downward radiative fluxes, wind speed, air temperature and water vapor pressure recorded above the surface were used as the boundary forcing for the SiB model. The predicted partitioning of the absorbed radiation into the sensible and latent heat fluxes compares well with observations and the various subcomponents of the model appear to operate realistically. The sensitivity of the model's energy balance calculations to changes in the various model parameters and the soil moisture initialization is examined. It is estimated that the model will generate uncertainties of the order of ±7% in the calculated net radiation, and up to ±25% in the calculated evapotranspiration rate, with typical values of ±15%.

  16. Crystal structure of stable protein CutA1 from psychrotrophic bacterium Shewanella sp. SIB1

    PubMed Central

    Sato, Aya; Yokotani, Sonoko; Tadokoro, Takashi; Tanaka, Shun-ichi; Angkawidjaja, Clement; Koga, Yuichi; Takano, Kazufumi; Kanaya, Shigenori

    2011-01-01

    CutA1 is widely found in bacteria, plants and animals, including humans. The functions of CutA1, however, have not been well clarified. It is known that CutA1s from Pyrococcus horikoshii, Thermus thermophilus and Oryza sativa unfold at temperatures remarkably higher than the growth temperatures of the host organisms. In this work the crystal structure of CutA1 from the psychrotrophic bacterium Shewanella sp. SIB1 (SIB1–CutA1) in a trimeric form was determined at 2.7 Å resolution. This is the first crystal structure of a psychrotrophic CutA1. The overall structure of SIB1–CutA1 is similar to those of CutA1 from Homo sapiens, Escherichia coli, Pyrococcus horikoshii, Thermus thermophilus, Termotoga maritima, Oryza sativa and Rattus norvergicus. A peculiarity is observed in the β2 strand. The β2 strand is divided into two short β strands, β2a and β2b, in SIB1–CutA1. A thermal denaturation experiment revealed that SIB1–CutA1 does not unfold completely at 363 K at pH 7.0, although Shewanella sp. SIB1 cannot grow at temperatures exceeding 303 K. These results indicate that the trimeric structural motif of CutA1 is the critical factor in its unusually high stability and suggest that CutA1 needs to maintain its high stability in order to function, even in psychrotrophs. PMID:21169681

  17. Genotypic association analysis using discordant-relative-pairs.

    PubMed

    Yan, T; Yang, Y-N; Cheng, X; DeAngelis, M M; Hoh, J; Zhang, H

    2009-01-01

    In practice, family-based design has been widely used in disease-gene association analysis. The major advantage of such design is that it is not subject to spurious association due to population structure such as population stratification (PS) and admixture. A disadvantage is that parental genotypes are hard to obtain if the disease is late onset for which a discordant-relative-pair design is useful. Designs of such kind include full-sib-pair, half-sib-pair, first-cousin-pair, and so on. The closer the relatedness of the pair, the less possible that they are subject to population stratification. On the other hand, the association test using close relative-pairs may be less powerful due to over-matching. Trade-off between these two factors (population structure and over-matching) is the major concern of this study. Some tests, namely McNemar's test, matched Cochran-Armitage trend tests (CATTs), matched maximum efficient robust test (MERT), and Bhapkar's test, are used for testing disease-gene association based on relative-pair designs. These tests are shown to be valid in the presence of PS but not admixture. Numerical studies show that the McNemar's test, additive CATT, MERT, and Bhapkar's test are robust in power, but none of them is uniformly more powerful than the others. In most simulations, the power of any of the tests increases as the pair is more distant. The proposed methods are applied to two real examples. PMID:19040657

  18. Non-random X chromosome inactivation in an affected twin in a monozygotic twin pair discordant for Wiedemann-Beckwith syndrome

    SciTech Connect

    Oestavik, R.E.; Eiklid, K.; Oerstavik, K.H.

    1995-03-27

    Wiedemann-Beckwith syndrome (WBS) is a syndrome including exomphalos, macroglossia, and generalized overgrowth. The locus has been assigned to 11p15, and genomic imprinting may play a part in the expression of one or more genes involved. Most cases are sporadic. An excess of female monozygotic twins discordant for WBS have been reported, and it has been proposed that this excess could be related to the process of X chromosome inactivation. We have therefore studied X chromosome inactivation in 13-year-old monozygotic twin girls who were discordant for WBS. In addition, both twins had Tourette syndrome. The twins were monochorionic and therefore the result of a late twinning process. This has also been the case in previously reported discordant twin pairs with information on placentation. X chromosome inactivation was determined in DNA from peripheral blood cells by PCR analysis at the androgen receptor locus. The affected twin had a completely skewed X inactivation, where the paternal allele was on the active X chromosome in all cells. The unaffected twin had a moderately skewed X inactivation in the same direction, whereas the mother had a random pattern. Further studies are necessary to establish a possible association between the expression of WBS and X chromosome inactivation. 18 refs., 2 figs., 1 tab.

  19. Using interviews and peer pairs to better understand how school environments affect young children's playground physical activity levels: a qualitative study.

    PubMed

    Parrish, Anne-Maree; Yeatman, Heather; Iverson, Don; Russell, Ken

    2012-04-01

    School break times provide a daily opportunity for children to be active; however, research indicates this time is underutilized. Reasons for low children's playground activity levels have primarily focused on physical barriers. This research aimed to contribute to physical environmental findings affecting children's playground physical activity levels by identifying additional variables through the interview process. Thirteen public schools were included in the sample (total 2946 children). Physical activity and environmental data were collected over 3 days. Environmental variables were manually assessed at each of the 13 schools. Observational data were used to determine which three schools were the most and least active. The principal, three teachers and 20 students in Grades 4-6 from these six schools (four lower and two average socioeconomic status) were invited to participate in the interview process. Student interviews involved the paired interview technique. The main themes generated from the school interviews included the effect of non-fixed equipment (including balls), playground markings, playground aesthetics, activity preference, clothing, the amount of break time available for play, teacher playground involvement, gender, bullying, school policies, student confidence in break-time activity and fundamental movement skills. The effect of bullying on playground physical activity levels was concerning. PMID:21712499

  20. A note on the change in gene frequency of a selected allele in partial full-sib mating populations

    SciTech Connect

    Caballero, A.

    1996-02-01

    The change in gene frequency of a selected allele in partial full-sib mating populations was analyzed. The implications of these papers is important in terms of the fixation probability of genes because, for the same equilibrium inbreeding coefficient, fixation rates of mutant genes would be larger for partial full-sib mating than for partial selfing. 4 refs.

  1. Renal dysfunction in sibs with band like calcification with simplified gyration and polymicrogyria: Report of a new mutation and review of literature.

    PubMed

    Aggarwal, Shagun; Bahal, Ashish; Dalal, Ashwin

    2016-01-01

    Band like calcification with simplified gyration and polymicrogyria (BLC-PMG) is a distinct neuroradiological phenotype initially reported as a pseudo-TORCH syndrome and known to result from biallelic mutations in the Occludin(OCLN) gene. This is report of a family of Indian origin with two affected sibs and segregation of a homozygous novel OCLN mutation in the exon 3(NG_028291.1(OCLN_v001):c.252delC). A literature review suggests that renal dysfunction may be an unrecognized phenotypic manifestation of OCLN mutations and monitoring for the same should form part of the clinical care of these individuals. PMID:26689621

  2. Association of syndactyly, ectodermal dysplasia, and cleft lip and palate: report of two sibs from Turkey.

    PubMed Central

    Oğur, G; Yüksel, M

    1988-01-01

    Two Turkish sibs, products of a second cousin marriage, with tetramelic syndactyly, ectodermal dysplasia, cleft lip and palate, renal anomalies, and mental retardation are reported. Similarities between these two brothers and previously reported cases and their mode of transmission are discussed. Images PMID:2832607

  3. Maternal systemic lupus erythematosus and chondrodysplasia punctata in two sibs: phenocopy or coincidence?

    PubMed Central

    Elçioglu, N; Hall, C M

    1998-01-01

    Two sibs with chondrodysplasia punctata in whom the mother was suffering from systemic lupus erythematosus are presented and the radiological features described. Comparison with other forms of chondrodysplasia punctata with a review of the relevant publications is presented and the possible association with maternal systemic lupus erythematosus is highlighted. Images PMID:9719382

  4. Endophyte Effect on Seedling Vigor in 19 Half-sib Familes of Tall Fescue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seedling mass and emergence force were studied in two greenhouse experiments using 19 half-sib families of ‘Kentucky 31' tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] each of which was produced from genotypes with or without the common toxic endophyte [Neotyphodium coenophialum (Morgan-Jones ...

  5. A large set of Finnish affected sibling pair families with type 2 diabetes suggests susceptibility loci on chromosomes 6, 11, and 14.

    PubMed

    Silander, Kaisa; Scott, Laura J; Valle, Timo T; Mohlke, Karen L; Stringham, Heather M; Wiles, Kerry R; Duren, William L; Doheny, Kimberly F; Pugh, Elizabeth W; Chines, Peter; Narisu, Narisu; White, Peggy P; Fingerlin, Tasha E; Jackson, Anne U; Li, Chun; Ghosh, Soumitra; Magnuson, Victoria L; Colby, Kimberly; Erdos, Michael R; Hill, Jason E; Hollstein, Pablo; Humphreys, Kathleen M; Kasad, Roshni A; Lambert, Jessica; Lazaridis, Konstantinos N; Lin, George; Morales-Mena, Anabelle; Patzkowski, Kristin; Pfahl, Carrie; Porter, Rachel; Rha, David; Segal, Leonid; Suh, Yong D; Tovar, Jason; Unni, Arun; Welch, Christian; Douglas, Julie A; Epstein, Michael P; Hauser, Elizabeth R; Hagopian, William; Buchanan, Thomas A; Watanabe, Richard M; Bergman, Richard N; Tuomilehto, Jaakko; Collins, Francis S; Boehnke, Michael

    2004-03-01

    The aim of the Finland-United States Investigation of NIDDM Genetics (FUSION) study is to identify genes that predispose to type 2 diabetes or are responsible for variability in diabetes-related traits via a positional cloning and positional candidate gene approach. In a previously published genome-wide scan of 478 Finnish affected sibling pair (ASP) families (FUSION 1), the strongest linkage results were on chromosomes 20 and 11. We now report a second genome-wide scan using an independent set of 242 Finnish ASP families (FUSION 2), a detailed analysis of the combined set of 737 FUSION 1 + 2 families (495 updated FUSION 1 families), and fine mapping of the regions of chromosomes 11 and 20. The strongest FUSION 2 linkage results were on chromosomes 6 (maximum logarithm of odds score [MLS] = 2.30 at 95 cM) and 14 (MLS = 1.80 at 57 cM). For the combined FUSION 1 + 2 families, three results were particularly notable: chromosome 11 (MLS = 2.98 at 82 cM), chromosome 14 (MLS = 2.74 at 58 cM), and chromosome 6 (MLS = 2.66 at 96 cM). We obtained smaller FUSION 1 + 2 MLSs on chromosomes X (MLS = 1.27 at 152 cM) and 20p (MLS = 1.21 at 20 cM). Among the 10 regions that showed nominally significant evidence for linkage in FUSION 1, four (on chromosomes 6, 11, 14, and X) also showed evidence for linkage in FUSION 2 and stronger evidence for linkage in the combined FUSION 1 + 2 sample. PMID:14988269

  6. Quantitative trait loci analysis for growth and carcass traits in a half-sib family of purebred Japanese Black (Wagyu) cattle.

    PubMed

    Mizoshita, K; Watanabe, T; Hayashi, H; Kubota, C; Yamakuchi, H; Todoroki, J; Sugimoto, Y

    2004-12-01

    We used a half-sib family of purebred Japanese Black (Wagyu) cattle to locate economically important quantitative trait loci. The family was composed of 348 fattened steers, 236 of which were genotyped for 342 microsatellite markers spanning 2,664 cM of 29 bovine autosomes. The genome scan revealed evidence of 15 significant QTL (<5% chromosome-wise level) affecting growth and carcass traits. Of the 15 QTL, six QTL were significant at the 5% experiment-wise level and were located in bovine chromosomes (BTA) 4, 5, and 14. We analyzed these three chromosomes in more detail in the 348 steers, with an average marker interval of 1.2 cM. The second scan revealed that the same haplotype of the BTA 4 region (52 to 67 cM) positively affected LM area and marbling. We confirmed the QTL for carcass yield estimate on BTA 5 in the region of 45 to 54 cM. Five growth-related QTL located on BTA 14, including slaughter and carcass weights, were positively affected by the same region of the haplotype of BTA 14 (29-51 cM). These data should provide a useful reference for further marker-assisted selection in the family and positional cloning research. The research indicates that progeny design with moderate genotyping efforts is a powerful method for detecting QTL in a purebred half-sib family. PMID:15537759

  7. Multi-pair states in electron-positron pair creation

    NASA Astrophysics Data System (ADS)

    Wöllert, Anton; Bauke, Heiko; Keitel, Christoph H.

    2016-09-01

    Ultra strong electromagnetic fields can lead to spontaneous creation of single or multiple electron-positron pairs. A quantum field theoretical treatment of the pair creation process combined with numerical methods provides a description of the fermionic quantum field state, from which all observables of the multiple electron-positron pairs can be inferred. This allows to study the complex multi-particle dynamics of electron-positron pair creation in-depth, including multi-pair statistics as well as momentum distributions and spin. To illustrate the potential benefit of this approach, it is applied to the intermediate regime of pair creation between nonperturbative Schwinger pair creation and perturbative multiphoton pair creation where the creation of multi-pair states becomes nonnegligible but cascades do not yet set in. Furthermore, it is demonstrated how spin and helicity of the created electrons and positrons are affected by the polarization of the counterpropagating laser fields, which induce the creation of electron-positron pairs.

  8. Supporting NEESPI with Data Services - The SIB-ESS-C e-Infrastructure

    NASA Astrophysics Data System (ADS)

    Gerlach, R.; Schmullius, C.; Frotscher, K.

    2009-04-01

    Data discovery and retrieval is commonly among the first steps performed for any Earth science study. The way scientific data is searched and accessed has changed significantly over the past two decades. Especially the development of the World Wide Web and the technologies that evolved along shortened the data discovery and data exchange process. On the other hand the amount of data collected and distributed by earth scientists has increased exponentially requiring new concepts for data management and sharing. One such concept to meet the demand is to build up Spatial Data Infrastructures (SDI) or e-Infrastructures. These infrastructures usually contain components for data discovery allowing users (or other systems) to query a catalogue or registry and retrieve metadata information on available data holdings and services. Data access is typically granted using FTP/HTTP protocols or, more advanced, through Web Services. A Service Oriented Architecture (SOA) approach based on standardized services enables users to benefit from interoperability among different systems and to integrate distributed services into their application. The Siberian Earth System Science Cluster (SIB-ESS-C) being established at the University of Jena (Germany) is such a spatial data infrastructure following these principles and implementing standards published by the Open Geospatial Consortium (OGC) and the International Organization for Standardization (ISO). The prime objective is to provide researchers with focus on Siberia with the technical means for data discovery, data access, data publication and data analysis. The region of interest covers the entire Asian part of the Russian Federation from the Ural to the Pacific Ocean including the Ob-, Lena- and Yenissey river catchments. The aim of SIB-ESS-C is to provide a comprehensive set of data products for Earth system science in this region. Although SIB-ESS-C will be equipped with processing capabilities for in-house data generation

  9. Critical Schwinger Pair Production

    NASA Astrophysics Data System (ADS)

    Gies, Holger; Torgrimsson, Greger

    2016-03-01

    We investigate Schwinger pair production in spatially inhomogeneous electric backgrounds. A critical point for the onset of pair production can be approached by fields that marginally provide sufficient electrostatic energy for an off-shell long-range electron-positron fluctuation to become a real pair. Close to this critical point, we observe features of universality which are analogous to continuous phase transitions in critical phenomena with the pair-production rate serving as an order parameter: electric backgrounds can be subdivided into universality classes and the onset of pair production exhibits characteristic scaling laws. An appropriate design of the electric background field can interpolate between power-law scaling, essential Berezinskii-Kosterlitz-Thouless-type scaling, and a power-law scaling with log corrections. The corresponding critical exponents only depend on the large-scale features of the electric background, whereas the microscopic details of the background play the role of irrelevant perturbations not affecting criticality.

  10. Critical Schwinger Pair Production.

    PubMed

    Gies, Holger; Torgrimsson, Greger

    2016-03-01

    We investigate Schwinger pair production in spatially inhomogeneous electric backgrounds. A critical point for the onset of pair production can be approached by fields that marginally provide sufficient electrostatic energy for an off-shell long-range electron-positron fluctuation to become a real pair. Close to this critical point, we observe features of universality which are analogous to continuous phase transitions in critical phenomena with the pair-production rate serving as an order parameter: electric backgrounds can be subdivided into universality classes and the onset of pair production exhibits characteristic scaling laws. An appropriate design of the electric background field can interpolate between power-law scaling, essential Berezinskii-Kosterlitz-Thouless-type scaling, and a power-law scaling with log corrections. The corresponding critical exponents only depend on the large-scale features of the electric background, whereas the microscopic details of the background play the role of irrelevant perturbations not affecting criticality. PMID:26991162

  11. Pick a Pair. Pancake Pairs

    ERIC Educational Resources Information Center

    Miller, Pat

    2005-01-01

    Cold February weather and pancakes are a traditional pairing. Pancake Day began as a way to eat up the foods that were abstained from in Lent--traditionally meat, fat, eggs and dairy products. The best-known pancake event is The Pancake Day Race in Buckinghamshire, England, which has been run since 1445. This column describes pairs of books that…

  12. SIB-ESS-C - A Spatial Data Infrastructure to Facilitate Earth System Science in Siberia

    NASA Astrophysics Data System (ADS)

    Schmullius, C. C.; Gerlach, R.; Hese, S.

    2006-12-01

    The potential of Spatial Data Infrastructures (SDI) to share geoinformation and services over the Internet has been widely recognized and various initiatives (e.g. INSPIRE, GMES, GEOSS) are actively engaged to implement such systems on local, national or global level. Standards published by the Open Geospatial Consortium (OGC), the International Organization for Standardization (ISO) or the World Wide Web Consortium (W3C) provide the basis for distributed yet interoperable SDI's. Following the available guidelines and standards the Siberian Earth System Science Cluster (SIB-ESS-C) is being developed as a spatial data infrastructure for remote sensing product generation, data dissemination and scientific data analysis. This paper describes the concept of the Siberian Earth System Science Cluster. SIB-ESS-C emerged from the EU funded SIBERIA-II project (EVG2-2001-00008, 2002-2005) which was a joint Russian-European remote sensing project focusing on a 300 Million ha area in the central Siberian region. This area represents a significant part of the Earth's boreal biome which plays a critical role in global climate change in Northern Eurasia. The overall objective of the SIBERIA-II project was to demonstrate the viability of full carbon accounting including greenhouse gases (GHG) on a regional basis using state-of-the-art environmental methods and advanced remote sensing technologies. The tools and systems which have been employed include a selected yet spectrally and temporally diverse set of 15 Earth observation instruments on 8 satellites, detailed GIS databases and Dynamic Global Vegetation Models to account for fluxes between land and atmosphere. The data sets and value-added products created within the SIBERIA-II project will form the basic set of products for SIB-ESS-C. These products include regional maps of land cover, fire induced disturbances, phenology, snow depth, snow melt date, onset and duration of freeze and thaw, LAI and others. Since these products

  13. Testing the Simple Biosphere model (SiB) using point micrometeorological and biophysical data

    NASA Technical Reports Server (NTRS)

    Sellers, P. J.; Dorman, J. L.

    1987-01-01

    The suitability of the Simple Biosphere (SiB) model of Sellers et al. (1986) for calculation of the surface fluxes for use within general circulation models is assessed. The structure of the SiB model is described, and its performance is evaluated in terms of its ability to realistically and accurately simulate biophysical processes over a number of test sites, including Ruthe (Germany), South Carolina (U.S.), and Central Wales (UK), for which point biophysical and micrometeorological data were available. The model produced simulations of the energy balances of barley, wheat, maize, and Norway Spruce sites over periods ranging from 1 to 40 days. Generally, it was found that the model reproduced time series of latent, sensible, and ground-heat fluxes and surface radiative temperature comparable with the available data.

  14. Keratoconus posticus circumscriptus, cleft lip and palate, genitourinary abnormalities, short stature, and mental retardation in sibs

    PubMed Central

    Young, I D; Macrae, W G; Hughes, H E; Crawford, J S

    1982-01-01

    This paper describes two sibs in each of whom Keratoconus posticus circumscriptus is associated with multiple abnormalities. These include short stature, mental retardation, cleft lip and palate, and vertebral anomalies. The authors have been unable to trace any former reports of an identical condition and suggest that the findings in these children may represent a previously unrecognised malformation syndrome showing probable autosomal recessive inheritance. Images PMID:7143385

  15. Two sibs with chorioretinal dystrophy, hypogonadotrophic hypogonadism, and cerebellar ataxia: Boucher-Neuhäuser syndrome.

    PubMed Central

    Rump, R; Hamel, B C; Pinckers, A J; van Dop, P A

    1997-01-01

    We describe two sibs with chorioretinal dystrophy, hypogonadotrophic hypogonadism, and cerebellar ataxia, Boucher-Neuhäuser syndrome, a rare but distinct pleiotropic single gene disorder with an autosomal recessive pattern of inheritance. The cases presented illustrate that this syndrome is still poorly recognised. We provide a review and analysis of previously reported cases and the differential diagnosis, which might aid in the identification of additional cases. Images PMID:9321767

  16. New styrene-b-isobutylene-b-styrene (SIBS) glaucoma drainage implant

    NASA Astrophysics Data System (ADS)

    Orozco, Marcia A.; Acosta, Ana C.; Espana, Edgar M.; Pinchuk, Leonard; Weber, Bruce; Davis, Stewart; Arrieta, Esdras; Dubovy, Sander; Fantes, Francisco; Aly, Mohamed; Zhou, Yonghua; Parel, Jean-Marie

    2006-02-01

    Purpose: To design and test the Miami-InnFocus Drainage Implant (MiDi) as a glaucoma shunt that is biocompatible, flexible, and significantly smaller than existing commercial implants in order to prevent postoperative hypotony, inflammation, scarring, erosion, and extrusion. Methods: A new biomaterial composed of styrene-b-isobutylene-b-styrene (SIBS) was used in a novel design for a glaucoma drainage implant. The implant consists of a tube 11mm long with an inner diameter of 70, 100, and 150 μm and outer diameter of 250 μm with a 1mm2 tab located 4.5mm from the proximal tip to prevent migration. The device was implanted in 15 New Zealand White rabbits for biocompatibility and efficacy testing. A similarly designed implant made of polydimethylsiloxane was implanted in 6 other animals as a pseudo-control. Typical GDI implantation technique was modified for this device. The proximal end of the new SIBS implant was inserted 2mm into the anterior chamber and the distal end placed in a subconjunctival space created by the surgeon. Biocompatibility of the device was studied by slit-lamp follow-up and intraocular pressure (IOP) measurements recorded periodically. Results: Biocompatibility of the MiDi was excellent. A low and diffuse bleb was observed with these devices. All SIBS tubes were patent 9 months after insertion. Immunostaining demonstrated non-continuous deposition of collagen with virtually no encapsulation. No macrophages or myofibroblast were visible around the SIBS polymer which was found more bioinert than the control PDMS. Conclusion: This newly designed glaucoma implant is clinically biocompatible in the rabbit model and maintained 100% patency at 9 months.

  17. Ab Initio Calculated Thermodynamic Properties of Mo5SiB2 Phase and Nb5SiB2 Phase

    NASA Astrophysics Data System (ADS)

    Kim, Sungtae; Park, J. S.

    2013-11-01

    Due to their attractive high-temperature properties, multiphase Mo-Si-B alloys in the Mo-rich Mo-Si-B ternary system have been identified for high-temperature applications. The ternary intermetallic T2 (Mo5SiB2) phase is a central feature of the phase equilibria within this ternary system. Experimental stability analyses of the T2 phase shows its broad homogeneous composition ranges that can yield a constitutional defect structure such as vacancies for Mo-rich compositions and antisite defects for Mo-lean compositions. Previous thermodynamic model did not conform to the defect structures as reported in experiments, and thus subsequently a new sublattice thermodynamic model for the T2 phase is initiated in this study. To support the new sublattice thermodynamic model, ab initio calculations were implemented to compute formation energy data. The calculated formation energy data explain a source for broad compositional homogeneity range of T2 structure.

  18. Winning Pairs.

    ERIC Educational Resources Information Center

    Monsour, Florence

    2000-01-01

    Mentoring programs that pair experienced and first-time teachers are gaining prominence in supporting, developing, and retaining new teachers. The successful Beginning Teacher Assistance program at University of Wisconsin-River Falls was designed to give new K-12 teachers the opportunity for yearlong, structured support from mentor teachers. (MLH)

  19. Larval and juvenile growth performance of Manila clam hybrids of two full-sib families

    NASA Astrophysics Data System (ADS)

    Huo, Zhongming; Yan, Xiwu; Zhao, Liqiang; Liang, Jian; Yang, Feng; Zhang, Guofan

    2015-06-01

    In order to determine whether growth performance could be improved by hybridizing full-sib families of Manila clam ( Ruditapes philippinarum), crosses between two full-sib families including self and reciprocal crosses were carried out. The effects of heterosis, combining ability and interaction on the growth of shell length were estimated. The results showed that the growth of hybrid larvae was intermediate between parents on days 6 and 9. Heterosis on shell length was observed, which varied at juvenile stage. The cross of ♂A × ♀B ( Hp varied between 10.41% and 68.27%) displayed larger heterosis than ♂B × ♀A ( Hp varied between 1.89% and 32.33%) did, suggesting that ♂A × ♀B was an ideal hatchery method of improving the growth performance of Manila clam. The variances of general combining ability (GCA), special combining ability (SCA) and interaction (I) were significant in shell length (P < 0.05), indicating that both additive and non-additive genetic factors were important contributors to the growth of larvae and juveniles. The GCA for shell length of ♂A × ♀B was higher than that of ♂B × ♀A at both larval and juvenile stages. This confirmed that the cross between ♂A and ♀B showed great growth in shell length. In summary, the growth of Manila clam seeds could be improved by hybridizing selected parents from large numbers of full-sib families.

  20. A simplified treatment of SiB's land surface albedo parameterization

    NASA Technical Reports Server (NTRS)

    Koster, Randal D.; Suarez, Max J.

    1991-01-01

    The earlier presented surface albedo parameterization is simplified by assuming that the reflectance of direct solar radiation is a simple function of solar zenith angle. The function chosen contains three parameters that vary with vegetation type, greenness, and leaf area index. Tables of parameter values are presented. Using these tables, SiB's (Simple Biosphere model) absorbances of direct solar radiation can be reproduced with an average relative error of less than 0.5 percent. Finally, the direct reflectance function is integrated over zenith angle to produce an equation for the surface reflectance of diffuse radiation.

  1. Multiple congenital malformations in two sibs reminiscent of hydrolethalus and pseudotrisomy 13 syndromes

    SciTech Connect

    Dincsoy, M.Y.; Salih, M.A.M.; Al-Jurayyan, N.

    1995-04-10

    We report on two sibs, born to consanguineous parents, with defects of the midline including cleft lip and palate, flat nose, hypotelorism, and dysgenesis of corpus callosum, in addition to short limbs, radiolucent tibial notch, digital anomalies, ambiguous genitalia, and hypopituitarism. In spite of the similarities between this condition and the hydrolethalus and pseudotrisomy 13 syndromes, our patients had neither preaxial nor postaxial polydactyly, but had previously undescribed bilateral radiolucent tibial notch, which is not known to be part of those two syndromes. The cases presented here may very well represent a new autosomal recessive syndrome. 20 refs., 4 figs., 1 tab.

  2. Using Interviews and Peer Pairs to Better Understand How School Environments Affect Young Children's Playground Physical Activity Levels: A Qualitative Study

    ERIC Educational Resources Information Center

    Parrish, Anne-Maree; Yeatman, Heather; Iverson, Don; Russell, Ken

    2012-01-01

    School break times provide a daily opportunity for children to be active; however, research indicates this time is underutilized. Reasons for low children's playground activity levels have primarily focused on physical barriers. This research aimed to contribute to physical environmental findings affecting children's playground physical activity…

  3. Very low levels of high density lipoprotein cholesterol in four sibs of a family with non-neuropathic Niemann-Pick disease and sea-blue histiocytosis.

    PubMed Central

    Viana, M B; Giugliani, R; Leite, V H; Barth, M L; Lekhwani, C; Slade, C M; Fensom, A

    1990-01-01

    Very low serum levels of high density lipoprotein cholesterol ranging from 8.6 to 13.9 mg/dl were detected in four out of 12 sibs of a Brazilian kindred with the non-neuropathic form of Niemann-Pick disease. Hepatosplenomegaly, interstitial infiltration of the lungs, absence of neurological signs, sea-blue histiocytes in the bone marrow and liver, and high values for serum acid phosphatase (18 to 32 U/l) were common to all affected children. Leucocyte acid sphingomyelinase activity ranged from 3.6 to 6.5% of mean control values, and fibroblast activity from 9 to 13% of mean controls. The parents had low-normal levels. The relationship between these findings is unclear and deserves further investigation. Images PMID:2120445

  4. Implementing the Simple Biosphere Model (SiB) in a general circulation model: Methodologies and results

    NASA Technical Reports Server (NTRS)

    Sato, N.; Sellers, P. J.; Randall, D. A.; Schneider, E. K.; Shukla, J.; Kinter, J. L., III; Hou, Y.-T.; Albertazzi, E.

    1989-01-01

    The Simple Biosphere MOdel (SiB) of Sellers et al., (1986) was designed to simulate the interactions between the Earth's land surface and the atmosphere by treating the vegetation explicitly and relistically, thereby incorporating biophysical controls on the exchanges of radiation, momentum, sensible and latent heat between the two systems. The steps taken to implement SiB in a modified version of the National Meteorological Center's spectral GCM are described. The coupled model (SiB-GCM) was used with a conventional hydrological model (Ctl-GCM) to produce summer and winter simulations. The same GCM was used with a conventional hydrological model (Ctl-GCM) to produce comparable 'control' summer and winter variations. It was found that SiB-GCM produced a more realistic partitioning of energy at the land surface than Ctl-GCM. Generally, SiB-GCM produced more sensible heat flux and less latent heat flux over vegetated land than did Ctl-GCM and this resulted in the development of a much deeper daytime planetary boundary and reduced precipitation rates over the continents in SiB-GCM. In the summer simulation, the 200 mb jet stream and the wind speed at 850 mb were slightly weakened in the SiB-GCM relative to the Ctl-GCM results and equivalent analyses from observations.

  5. Electrochemical properties of carbon-coated Si/B composite anode for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Kim, Hyung Sun; Chung, Kyung Yoon; Cho, Byung Won

    Carbon-coated Si and Si/B composite powders prepared by hydrocarbon gas (argon + 10 mol% propylene) pyrolysis were investigated as the anodes for lithium-ion batteries. Carbon-coated silicon anode demonstrated the first discharge and charge capacity as 1568 mAh g -1 and 1242 mAh g -1, respectively, with good capacity retention for 10 cycles. The capacity fading rate of carbon-coated Si/B composite anode decreased as the amounts of boron increased. In addition, the cycle life of carbon-coated Si/B/graphite composite anode has been significantly improved by using sodium carboxymethyl cellulose (NaCMC) and styrene butadiene rubber (SBR)/NaCMC mixture binders compared to the poly(vinylidene fluoride, PVdF) binder. A reversible capacity of about 550 mAh g -1 has been achieved at 0.05 mAm g -1 rate and its capacity could be maintained up to 450 mAh g -1 at high rate of 0.2 mAm g -1 even after 30 cycles. The improvement of the cycling performance is attributed to the lower interfacial resistance due to good electric contact between silicon particles and copper substrate.

  6. Sib risk and the dizygotic twin concordance rate for multiple sclerosis.

    PubMed Central

    James, W H

    1985-01-01

    Data have been reviewed on sib risk and the dizygotic twin concordance rate in multiple sclerosis. Even when rigorous criteria are applied, the dizygotic twin concordance rate for multiple sclerosis is apparently higher (perhaps 10 times higher) than could be explained by the sib risk. In contrast, twins with Parkinson's disease have low concordance rates even when ascertainment is by informal methods. It is concluded that such methods of ascertainment are not as biased as has been suggested, and that the high concordance rates reported for multiple sclerosis are a characteristic of the disease rather than an artifact of the ascertainment. Three hypotheses are considered which might, in principle, explain this high dizygotic twin concordance rate in multiple sclerosis: 1 One is certainly false, viz, that it is due to an excessive liability of dizygotic twins to the disease. 2 It is possible that a pathogen occurs in early infancy or in pregnancy itself. 3 It seems more likely that the high concordance rate may be explained in terms of age related events or sequences of events. (If such events were pathogenic for one member of a sibship, they would be pathogenic for another only if it were a co-twin). PMID:4039354

  7. Variability studies for needle and wood traits of different half sib progenies of Pinus roxburghii Sargent.

    PubMed

    Bhat, Sheeraz Saleem; Singh, N B; Sankhyan, H P; Sharma, K R

    2016-04-01

    Genetic variability studies for needle and wood traits were carried out for the different half sib progenies of Chir pine, raised in 1985 at the main campus of University. There existed a significant variation for these traits among the different half sib progenies, viz., needle length (18.1-24.6 cm), needle thickness (0.53-0.71 mm), number of stomata per mm of a row (7.3-12.0), specific gravity of wood (0.36-0.46), tracheid length (1.51-1.85) and moisture content of wood (47.76-58.81). This variability was found under genetic control, as all these progenies are growing under same environment, and are of same age. Traits having high heritability and genetic gain like, needle thickness, wood specific gravity, tracheid length and others, indicate high genetic control. This variability can be exploited in tree improvement programs through selection and breeding approaches for development of advanced generations. Correlation studies for different traits at genotypic and phenotypic levels provided the basic knowledge of association to chalk out efficient breeding strategy for higher productivity through indirect selection. PMID:27436914

  8. Severe infantile carnitine palmitoyltransferase II deficiency in 19-week fetal sibs.

    PubMed

    Meir, Karen; Fellig, Yakov; Meiner, Vardiella; Korman, Stanley H; Shaag, Avraham; Nadjari, Michel; Soffer, Dov; Ariel, Ilana

    2009-01-01

    Antenatal presentation of carnitine palmitoyltransferase type II deficiency due to mutations in the CPT2 gene has been rarely reported. We report an Ashkenazi Jewish family with 3 terminated pregnancies for multicystic kidneys and/or hydrocephalus. Fetal autopsy after termination of the couple's 4th pregnancy (sib 2) showed renal parenchyma replaced by cysts that appeared to increase in diameter toward the medulla. Fetopsy after termination of the 7th pregnancy (sib 3) revealed micrognathia; hypospadias; cystic renal dysplasia; hepatosteatosis; and lipid accumulation in the renal tubular epithelium, myocardium, and skeletal muscle. Microvascular proliferative changes and focal polymicrogyria were seen in the brain. A beta-oxidative enzyme deficiency was suspected. CPT2 gene analysis showed a homozygous complex haplotype for the F448L mutation associated with a c.del1238_1239AG (p.Q413fs) truncating mutation in exon 4. Carnitine palmitoyltransferase type II deficiency should be included in the differential diagnosis in fetuses of Ashkenazi origin with multicystic kidneys and unusual cerebral findings. PMID:19335026

  9. Lymphocyte interphase chromatin in healthy subjects, patients with Down's syndrome, and their parents and sibs.

    PubMed Central

    Fedorova, K N; Yudina, I E

    1982-01-01

    A study of the interphase chromatin structure of lymphocytes in healthy subjects, patients with Down's syndrome, and their parents and sibs was carried out by AO labelled fluorometry using our modification of DNP cell thermal denaturation. Analysis by the Sperry Univac 90/30-B computer showed that in 40% of healthy subjects the lymphocyte chromatin melting profiles had a regularly repeated curve with six (seven) maxima at definite temperatures. In the remaining 60% some regularly repeated deviations were present and were correlated with the sex of the subject examined. There were five subgroups in the female group and seven subgroups in the male group. In 97% of patients with Down's syndrome the lymphocyte chromatin melting profiles gave curves with three maxima at temperatures of 65, 85, and 92 degrees C (+/- 2 degrees). Maxima at 78 and 45 degrees C were absent. In 80% of the mothers of probands with Down's syndrome and in 30% of female sibships, lymphocyte melting profiles also produced curves with three maxima: 65, 85, and 92 degrees C (+/- 2 degrees). In view of the fact that similar changes were observed in mothers and female sibs only, we propose that some women may have genotypical peculiarities which may possibly contribute to the origin of this chromosome pathology. PMID:6218303

  10. Lymphocyte interphase chromatin in healthy subjects, patients with Down's syndrome, and their parents and sibs.

    PubMed

    Fedorova, K N; Yudina, I E

    1982-12-01

    A study of the interphase chromatin structure of lymphocytes in healthy subjects, patients with Down's syndrome, and their parents and sibs was carried out by AO labelled fluorometry using our modification of DNP cell thermal denaturation. Analysis by the Sperry Univac 90/30-B computer showed that in 40% of healthy subjects the lymphocyte chromatin melting profiles had a regularly repeated curve with six (seven) maxima at definite temperatures. In the remaining 60% some regularly repeated deviations were present and were correlated with the sex of the subject examined. There were five subgroups in the female group and seven subgroups in the male group. In 97% of patients with Down's syndrome the lymphocyte chromatin melting profiles gave curves with three maxima at temperatures of 65, 85, and 92 degrees C (+/- 2 degrees). Maxima at 78 and 45 degrees C were absent. In 80% of the mothers of probands with Down's syndrome and in 30% of female sibships, lymphocyte melting profiles also produced curves with three maxima: 65, 85, and 92 degrees C (+/- 2 degrees). In view of the fact that similar changes were observed in mothers and female sibs only, we propose that some women may have genotypical peculiarities which may possibly contribute to the origin of this chromosome pathology. PMID:6218303

  11. [Establishment of full-sib families of Branchiostoma japonicum and the relationship between early development patterns and larvae survival rates].

    PubMed

    Li, Wei-Ye; Wang, Yi-Quan

    2013-10-01

    One general requirement of individual laboratory animals is that they have known genetic backgrounds. However, ensuring such genetic similarity is difficult, and can be facilitated by breeding a full strain for experimentation. To this end, the authors bred 34 full-sib families of amphioxus larvae/embryos. Due to the high mortality of the embryos and larvae, only seven full-sib families of juvenile amphioxus Branchiostoma japonicum were obtained. Among them, the highest and lowest survival ratios were 32.4% and 1.67%, respectively, whereas the shortest metamorphosis and longest larva duration were 24 d and 42 d, respectively. These results demonstrate the feasibility of establishing full-sib families of amphioxus, and provide fundamental data needed for the future breeding of amphioxus strains. PMID:24115654

  12. The affected-pedigree-member method of linkage analysis.

    PubMed Central

    Weeks, D E; Lange, K

    1988-01-01

    This paper describes a generalization of the affected-sib-pair method of linkage analysis to pedigrees. By substituting identity-by-state relations for identity-by-descent relations, we develop a test statistic for detecting departures from independent segregation of disease and marker phenotypes. The statistic is based on the marker phenotypes of affected pedigree members only. Since it is more striking for distantly affected relatives to share a rare marker allele than a common marker allele, the statistic also includes a weighting factor based on allele frequency. The distributional properties of the statistic are investigated theoretically and by simulation. Part of the theoretical treatment entails generalizing Karigl's multiple-person kinship coefficients. When the test statistic is applied to pedigree data on Huntington disease, the null hypothesis of independent segregation between the marker locus and the disease locus is firmly rejected. In this case, as expected, there is a loss of power when compared with standard lod-score analysis. However, our statistic possesses the advantage of requiring no explicit assumptions about the mode of inheritance of the disease. This point is illustrated by application of the test statistic to data on rheumatoid arthritis. PMID:3422543

  13. Magnetic properties of Fe5SiB2 and its alloys with P, S, and Co

    NASA Astrophysics Data System (ADS)

    Werwiński, Mirosław; Kontos, Sofia; Gunnarsson, Klas; Svedlindh, Peter; Cedervall, Johan; Höglin, Viktor; Sahlberg, Martin; Edström, Alexander; Eriksson, Olle; Rusz, Ján

    2016-05-01

    Fe5SiB2 has been synthesized and magnetic measurements have been carried out, revealing that Msat=0.92 MA/m at T =300 K. The M versus T curve shows a broad peak around T =160 K. The anisotropy constant K1, estimated at T =300 K, is 0.25 MJ/m3. Theoretical analysis of Fe5SiB2 system has been carried out and extended to the full range of Fe5Si1 -xPxB2 ,Fe5P1 -xSxB2 , and (Fe1 -xCox )5SiB2 compositions. The electronic band structures have been calculated using the full-potential local-orbital minimum-basis scheme (FPLO-14). The calculated total magnetic moments are 9.20, 9.15, 9.59, and 2.42 μB per formula units of Fe5SiB2 ,Fe5PB2 ,Fe5SB2 , and Co5SiB2 , respectively. In agreement with experiment, magnetocrystalline anisotropy energies (MAE's) calculated for T =0 K change from a negative (easy-plane) anisotropy -0.28 MJ/m3 for Fe5SiB2 to the positive (easy-axis) anisotropy 0.35 MJ/m3 for Fe5PB2 . Further increase of the number of p electrons in Fe5P1 -xSxB2 leads to an increase of MAE up to 0.77 MJ/m3 for the hypothetical Fe5P0.4S0.6B2 composition. Volume variation and fixed spin moment calculations (FSM) performed for Fe5SiB2 show an inverse relation between MAE and magnetic moment in the region down to about 15% reduction of the spin moment. The alloying of Fe5SiB2 with Co is proposed as a practical realization of magnetic moment reduction, which ought to increase MAE. MAE calculated in virtual crystal approximation (VCA) for a full range of (Fe1 -xCox )5SiB2 compositions reaches the maximum value of 1.16 MJ/m3 at Co concentration x =0.3 , with the magnetic moment 7.75 μB per formula unit. Thus, (Fe0.7Co0.3 )5SiB2 is suggested as a candidate for a rare-earth free permanent magnet. For the stoichiometric Co5SiB2 there is an easy-plane magnetization, with the value of MAE=-0.15 MJ/m3.

  14. Genomewide Linkage Study in 1,176 Affected Sister Pair Families Identifies a Significant Susceptibility Locus for Endometriosis on Chromosome 10q26

    PubMed Central

    Treloar, Susan A.; Wicks, Jacqueline; Nyholt, Dale R.; Montgomery, Grant W.; Bahlo, Melanie; Smith, Vicki; Dawson, Gary; Mackay, Ian J.; Weeks, Daniel E.; Bennett, Simon T.; Carey, Alisoun; Ewen-White, Kelly R.; Duffy, David L.; O’Connor, Daniel T.; Barlow, David H.; Martin, Nicholas G.; Kennedy, Stephen H.

    2005-01-01

    Endometriosis is a common gynecological disease that affects up to 10% of women in their reproductive years. It causes pelvic pain, severe dysmenorrhea, and subfertility. The disease is defined as the presence of tissue resembling endometrium in sites outside the uterus. Its cause remains uncertain despite >50 years of hypothesis-driven research, and thus the therapeutic options are limited. Disease predisposition is inherited as a complex genetic trait, which provides an alternative route to understanding the disease. We seek to identify susceptibility loci, using a positional-cloning approach that starts with linkage analysis to identify genomic regions likely to harbor these genes. We conducted a linkage study of 1,176 families (931 from an Australian group and 245 from a U.K. group), each with at least two members—mainly affected sister pairs—with surgically diagnosed disease. We have identified a region of significant linkage on chromosome 10q26 (maximum LOD score [MLS] of 3.09; genomewide P = .047) and another region of suggestive linkage on chromosome 20p13 (MLS = 2.09). Minor peaks (with MLS > 1.0) were found on chromosomes 2, 6, 7, 8, 12, 14, 15, and 17. This is the first report of linkage to a major locus for endometriosis. The findings will facilitate discovery of novel positional genetic variants that influence the risk of developing this debilitating disease. Greater understanding of the aberrant cellular and molecular mechanisms involved in the etiology and pathophysiology of endometriosis should lead to better diagnostic methods and targeted treatments. PMID:16080113

  15. Magnetostructural transition in Fe5SiB2 observed with neutron diffraction

    NASA Astrophysics Data System (ADS)

    Cedervall, Johan; Kontos, Sofia; Hansen, Thomas C.; Balmes, Olivier; Martinez-Casado, Francisco Javier; Matej, Zdenek; Beran, Premysl; Svedlindh, Peter; Gunnarsson, Klas; Sahlberg, Martin

    2016-03-01

    The crystal and magnetic structure of Fe5SiB2 has been studied by a combination of X-ray and neutron diffraction. Also, the magnetocrystalline anisotropy energy constant has been estimated from magnetisation measurements. High quality samples have been prepared using high temperature synthesis and subsequent heat treatment protocols. The crystal structure is tetragonal within the space group I4/mcm and the compound behaves ferromagnetically with a Curie temperature of 760 K. At 172 K a spin reorientation occurs in the compound and the magnetic moments go from aligning along the c-axis (high T) down to the ab-plane (low T). The magnetocrystalline anisotropy energy constant has been estimated to 0.3 MJ/m3 at 300 K.

  16. F-1 Engine Test Firing at the S-IB Static Test Stand

    NASA Technical Reports Server (NTRS)

    1963-01-01

    The test laboratory of the Marshall Space Flight Center (MSFC) tested the F-1 engine, the most powerful rocket engine ever fired at MSFC. The engine was tested on the newly modified Saturn IB static test stand that had been used for three years to test the Saturn I eight-engine booster, S-I (first) stage. In 1961, the test stand was modified to permit static firing of the S-I/S-IB stage and the name of the stand was then changed to the S-IB Static Test Stand. Producing a combined thrust of 7,500,000 pounds, five F-1 engines powered the S-IC (first) stage of the Saturn V vehicle for the marned lunar mission.

  17. F-1 Engine Test Firing at the S-IB Static Test Stand

    NASA Technical Reports Server (NTRS)

    1963-01-01

    The test laboratory of the Marshall Space Flight Center (MSFC) tested the F-1 engine, the most powerful rocket engine ever fired at MSFC. The engine was tested on the newly modified Saturn IB Static Test Stand which had been used for three years to test the Saturn I eight-engine booster, S-I (first) stage. In 1961 the test stand was modified to permit static firing of the S-I/S-IB stage and the name of the stand was then changed to the S-IB Static Test Stand. Producing a combined thrust of 7,500,000 pounds, five F-1 engines powered the S-IC (first) stage of the Saturn V vehicle for the marned lunar mission.

  18. Optical and electrical properties of laser doped Si:B in the alloy range

    NASA Astrophysics Data System (ADS)

    Bhaduri, A.; Kociniewski, T.; Fossard, F.; Boulmer, J.; Débarre, D.

    2012-09-01

    We have probed the dopant activity of silicon B-doped by Gas Immersion Laser Doping (GILD). Here, we report on the comparison of optical, electrical and structural properties of Si:B, over a wide concentration range, up to 1.5 × 1021 cm-3 by steps of 1.5 × 1019 cm-3. Data obtained by reflectance FTIR spectroscopy are used within a Drude model to extract concentration, thickness and mobility. Resulting carrier concentration and conductivity are checked with 4-point probe electrical and X-ray diffraction measurements. FTIR proved to be very sensitive to the dopant distribution inside the layer, despite its thinness. It clearly reveals a moderate dopant accumulation at the interfaces.

  19. Cognitive Efficacy (SIB) of 13.3 Versus 4.6 mg/24 h Rivastigmine Patch in Severe Alzheimer's Disease.

    PubMed

    Isaacson, Richard S; Ferris, Steven; Velting, Drew M; Meng, Xiangyi

    2016-05-01

    Severe Impairment Battery (SIB) data from the 24-week, randomized, double-blind ACTivities of daily living and cognitION (ACTION) study suggest that patients with severe Alzheimer's disease (AD) benefit from treatment with 13.3 versus 4.6 mg/24 h rivastigmine patch. The objective of this retrospective analysis was to further examine the cognitive efficacy of 13.3 versus 4.6 mg/24 h rivastigmine patch on individual SIB items, and SIB domains derived using factor analysis of these items. Change from baseline at Week 24 on 9 new factor-defined domains and individual items was calculated and compared using effect sizes (Cohen's d). Numerically less decline was observed with 13.3 versus 4.6 mg/24 h patch on all domains and the majority of individual items. Largest least squares mean treatment differences were observed on "visuospatial reasoning," "object naming," "recognition," "design copying," "social agency," "ideational praxis," and "comprehension" domains. These findings suggest 13.3 mg/24 h rivastigmine patch demonstrates broad cognitive efficacy across a range of SIB items and domains in patients with severe AD. PMID:26371345

  20. Early growth performance of full-sib Acacia auriculiformis x Acacia mangium F1 hybrid progenies at three different sites

    NASA Astrophysics Data System (ADS)

    Shah Aimin, Atirah Abdullah; Abdullah, Mohd Zaki; Muhammad, Norwati; Ratnam, Wickneswari

    2014-09-01

    Field trials of 14 full sib Acacia auriculiformis x Acacia mangium F1 hybrid progenies were evaluated for growth performance at three sites (Bintulu, Mentakab and Segamat). Results indicated that there were significant differences (p> 0.05) for diameter breast height (Dbh) and total height (Ht) among the progenies and different sites. Superior progenies have been identified for future tree selection and improvement.

  1. The effect of multifunctional monomers/oligomers Additives on electron beam radiation crosslinking of poly (styrene-block-isoprene/butadiene-block-styrene) (SIBS)

    NASA Astrophysics Data System (ADS)

    Wu, Jinping; Soucek, Mark D.

    2016-02-01

    The effect of multifunctional monomers or oligomers (MFM/O) additives on electron beam (E-beam) radiation induced crosslinking of poly (styrene-block-isoprene/butadiene-block-styrene) (SIBS) was studied. Ten types of MFM/O were investigated, including trimethylolpropane trimethacrylate (TMPTMA), trimethylolpropane triacrylate (TMPTA), triallyl cyanurate (TAC), polybutadiene diacrylate (PB-diacrylate), ethylene glycol dimethylacrylate (EGDMA), butylene glycol dimethacrylate (BGDMA), 1,2-polybutadiene. The effects of MFM/O concentration and E-beam radiation dose on properties of SIBS were studied including tensile strength, elongation-at-break, modulus, gel content, equilibrium swelling and crosslink density. TMPTA significantly improved the tensile modulus and crosslink density of SIBS. SIBS with TMPTMA and TMTPMA with inhibitor showed a 50% increase in tensile strength. The solubility of MFM/O in SIBS was also investigated by a selective swelling method. The MFM/O were found to be soluble in both phases of SIBS. The viscosity of SIBS with methacrylate type MFM/O was stable at 200 °C.

  2. Highly Significant Linkage to the SLI1 Locus in an Expanded Sample of Individuals Affected by Specific Language Impairment

    PubMed Central

    2004-01-01

    Specific language impairment (SLI) is defined as an unexplained failure to acquire normal language skills despite adequate intelligence and opportunity. We have reported elsewhere a full-genome scan in 98 nuclear families affected by this disorder, with the use of three quantitative traits of language ability (the expressive and receptive tests of the Clinical Evaluation of Language Fundamentals and a test of nonsense word repetition). This screen implicated two quantitative trait loci, one on chromosome 16q (SLI1) and a second on chromosome 19q (SLI2). However, a second independent genome screen performed by another group, with the use of parametric linkage analyses in extended pedigrees, found little evidence for the involvement of either of these regions in SLI. To investigate these loci further, we have collected a second sample, consisting of 86 families (367 individuals, 174 independent sib pairs), all with probands whose language skills are ⩾1.5 SD below the mean for their age. Haseman-Elston linkage analysis resulted in a maximum LOD score (MLS) of 2.84 on chromosome 16 and an MLS of 2.31 on chromosome 19, both of which represent significant linkage at the 2% level. Amalgamation of the wave 2 sample with the cohort used for the genome screen generated a total of 184 families (840 individuals, 393 independent sib pairs). Analysis of linkage within this pooled group strengthened the evidence for linkage at SLI1 and yielded a highly significant LOD score (MLS = 7.46, interval empirical P<.0004). Furthermore, linkage at the same locus was also demonstrated to three reading-related measures (basic reading [MLS = 1.49], spelling [MLS = 2.67], and reading comprehension [MLS = 1.99] subtests of the Wechsler Objectives Reading Dimensions). PMID:15133743

  3. Multiple regression analysis of reading performance data from twin pairs with reading difficulties and nontwin siblings: the augmented model.

    PubMed

    Wadsworth, Sally J; Olson, Richard K; Willcutt, Erik G; DeFries, John C

    2012-02-01

    The augmented multiple regression model for the analysis of data from selected twin pairs was extended to facilitate analyses of data from twin pairs and nontwin siblings. Fitting this extended model to data from both selected twin pairs and siblings yields direct estimates of heritability (h2) and the difference between environmental influences shared by members of twin pairs and those of sib or twin-sib pairs (i.e., c2(t) - c2 (s)). When this model was fitted to reading performance data from 293 monozygotic and 436 dizygotic pairs selected for reading difficulties, and 291 of their nontwin siblings, h2 = .48 ± .22, p = .03, and c2 (t) - c2 (s) = .22 ± .12, p = .06. Although the test for differential shared environmental influences is only marginally significant, the results of this analysis suggest that environmental influences on reading performance that are shared by members of twin pairs (.36) may be substantially greater than those for less contemporaneous twin-sibling pairs (.14). PMID:22784461

  4. Pair Programming: Issues and Challenges

    NASA Astrophysics Data System (ADS)

    Lui, Kim Man; Barnes, Kyle Atikus; Chan, Keith C. C.

    Pair programming, two programmers collaborating on design, coding and testing, has been a controversial focus of interest as Agile Software Development continues to grow in popularity both among academics and practitioners. As a result of the many investigations into the effectiveness of pair programming in the last decade, many have come to realize that there are many hard-to-control factors in pair programming in particular and in empirical software engineering in general. Because of these factors, the results of many pair programming experiments are not easy to replicate and the relative productivity of pair and solo programming are still not fully understood. So far, it has been concluded by previous studies that pair programming productivity can vary, but few have shown how and why this is the case. In this chapter, we discuss a number of challenging factors in the adoption of pair programming and present an approach to deal with them. We discuss how different factors may affect our experimental outcomes and improve experiment design to reveal how and why pair programming can be made productive, at least, in controlled situations.

  5. Soil Surface Runoff Scheme for Improving Land-Hydrology and Surface Fluxes in Simple SiB (SSiB)

    NASA Technical Reports Server (NTRS)

    Sud, Y. C.; Mocko, David M.

    1999-01-01

    Evapotranspiration on land is hard to measure and difficult to simulate. On the scale of a GCM grid, there is large subgrid-scale variability of orography, soil moisture, and vegetation. Our hope is to be able to tune the biophysical constants of vegetation and soil parameters to get the most realistic space-averaged diurnal cycle of evaporation and its climatology. Field experiments such as First ISLSCP Field Experiment (FIFE), Boreal Ecosystem-Atmosphere Study (BOREAS), and LBA help a great deal in improving our evapotranspiration schemes. However, these improvements have to be matched with, and coupled to, consistent improvement in land-hydrology; otherwise, the runoff problems will intrinsically reflect on the soil moisture and evapotranspiration errors. Indeed, a realistic runoff simulation also ensures a reasonable evapotranspiration simulation provided the precipitation forcing is reliable. We have been working on all of the above problems to improve the simulated hydrologic cycle. Through our participation in the evaluation and intercomparison of land-models under the behest of Global Soil Wetness Project (GSWP), we identified a few problems with Simple SiB (SSIB; Xue et al., 1991) hydrology in regions of significant snowmelt. Sud and Mocko (1999) show that inclusion of a separate snowpack model, with its own energy budget and fluxes with the atmosphere aloft and soil beneath, helps to ameliorate some of the deficiencies of delayed snowmelt and excessive spring season runoff. Thus, much more realistic timing of melt water generation was simulated with the new snowpack model in the subsequent GSWP re-evaluations using 2 years of ISLSCP Initiative I forcing data for 1987 and 1988. However, we noted an overcorrection of the low meltwater infiltration of SSiB. While the improvement in snowmelt timing was found everywhere, the snowmelt infiltration has became excessive in some regions, e.g., Lena river basin. This leads to much reduced runoff in many basins as

  6. Simple biosphere model (SiB) for use within general circulation models

    SciTech Connect

    Sellers, P.J.; Mintz, Y.; Sud, Y.C.; Dalcher, A.

    1986-03-15

    A simple but realistic biosphere model has been developed for calculating the transfer of energy, mass and momentum between the atmosphere and the vegetated surface of the earth. The model is designed for use in atmospheric general circulation models. The vegetation in each terrestrial model grid area is represented by two distinct layers, either or both of which may be present or absent at any given location and time. The upper vegetation layer represents the perennial canopy of trees or shrubs, while the lower layer represents the annual ground cover of grasses and other herbaceous species. The local coverage of each vegetation layer may be fractional or complete but as the individual vegetation elements are considered to be evenly spaced, their root systems are assumed to extend uniformly throughout the entire grid area. The Simple Biosphere (SiB) has seven prognostic physical-state variables: two temperatures (one for the canopy and one for the ground cover and soil surface); two interception water stores (one for the canopy and one for the ground cover); and three soil moisture stores (two of which can be reached by the vegetation root systems and one underlying recharge layer into and out of which moisture is transferred only by hydraulic diffusion and gravitational drainage).

  7. Effect of plastic deformation on the magnetic properties and dislocation luminescence of isotopically enriched silicon {sup 29}Si:B

    SciTech Connect

    Koplak, O. V.; Shteynman, E. A.; Tereschenko, A. N.; Morgunov, R. B.

    2015-09-15

    A correlation between the temperature dependences of the D1-line intensity of dislocation luminescence and the magnetic moment of plastically deformed isotopically enriched crystals {sup 29}Si:B is found. It is established that the magnetic susceptibility of the deformed crystals obtained by integration of the spectra of electron spin resonance and the D1-line intensity undergo similar nonmonotonic variations with temperature varying in the range of 20–32 K.

  8. Thigmomorphogenesis: anatomical, morphological and mechanical analysis of genetically different sibs of Pinus taeda in response to mechanical perturbation

    NASA Technical Reports Server (NTRS)

    Telewski, F. W.; Jaffe, M. J.

    1986-01-01

    Twenty-three open pollinated families (half-sibs) and four controlled pollinated families (full-sibs) of Pinus taeda L. (loblolly pine) were grown in a greenhouse and analyzed for changes induced by mechanical perturbation (MP). These changes included inhibition of stem and needle elongation, bracing of branch nodes, and increased radial growth in the direction of the MP. Inhibition of stem elongation was the least variable feature measured. Leaf extension and stem diameter were highly variable between half-sibs. MP induced increased drag in greenhouse grown P. taeda in wind-tunnel tests. In P. taeda, MP induced decreased flexibility and increased elasticity and plasticity of the stem. The increased radial growth of the stems overrode the increase in elasticity, resulting in an overall decrease in flexibility. MP trees had a higher rupture point than non-MP controls. Increased radial growth is a result of more rapid cell divisions of the vascular cambium, resulting in increased numbers of tracheids. The decreased leader growth is partly due to a decreased tracheid length in response to MP.

  9. Linkage analysis between dominant and co-dominant makers in full-sib families of out-breeding species

    PubMed Central

    2010-01-01

    As high-throughput genomic tools, such as the DNA microarray platform, have lead to the development of novel genotyping procedures, such as Diversity Arrays Technology (DArT) and Single Nucleotide Polymorphisms (SNPs), it is likely that, in the future, high density linkage maps will be constructed from both dominant and co-dominant markers. Recently, a strictly genetic approach was described for estimating recombination frequency (r) between co-dominant markers in full-sib families. The complete set of maximum likelihood estimators for r in full-sib families was almost obtained, but unfortunately, one particular configuration involving dominant markers, segregating in a 3:1 ratio and co-dominant markers, was not considered. Here we add nine further estimators to the previously published set, thereby making it possible to cover all combinations of molecular markers with two to four alleles (without epistasis) in a full-sib family. This includes segregation in one or both parents, dominance and all linkage phase configurations. PMID:21637424

  10. TM9/Phg1 and SadA proteins control surface expression and stability of SibA adhesion molecules in Dictyostelium

    PubMed Central

    Froquet, Romain; le Coadic, Marion; Perrin, Jackie; Cherix, Nathalie; Cornillon, Sophie; Cosson, Pierre

    2012-01-01

    TM9 proteins form a family of conserved proteins with nine transmembrane domains essential for cellular adhesion in many biological systems, but their exact role in this process remains unknown. In this study, we found that genetic inactivation of the TM9 protein Phg1A dramatically decreases the surface levels of the SibA adhesion molecule in Dictyostelium amoebae. This is due to a decrease in sibA mRNA levels, in SibA protein stability, and in SibA targeting to the cell surface. A similar phenotype was observed in cells devoid of SadA, a protein that does not belong to the TM9 family but also exhibits nine transmembrane domains and is essential for cellular adhesion. A contact site A (csA)-SibA chimeric protein comprising only the transmembrane and cytosolic domains of SibA and the extracellular domain of the Dictyostelium surface protein csA also showed reduced stability and relocalization to endocytic compartments in phg1A knockout cells. These results indicate that TM9 proteins participate in cell adhesion by controlling the levels of adhesion proteins present at the cell surface. PMID:22219373

  11. Genetic variation for resistance to ergot (Claviceps purpurea [Fr.] Tul.) among full-sib families of five populations of winter rye (Secale cereale L.).

    PubMed

    Mirdita, V; Dhillon, B S; Geiger, H H; Miedaner, T

    2008-12-01

    Ergot (Claviceps purpurea [Fr.] Tul.) is a serious disease of rye (Secale cereale L.) and it adversely affects the quality of grain. The present investigation was undertaken to study genotypic variability among full-sib families (FSF) of five open-pollinated (OP) winter rye populations of highly diverse origin, namely Dankovskie Selekcyine (Poland), Charkovskaja (Ukraine), NEM4 (Russia), Halo and Carokurz, both from Germany. About 50 FSF were developed at random in each population, and the FSF of each population were evaluated in separate but adjacent experiments conducted in four environments under artificial inoculation. A mixture of conidia of C. purpurea isolates was sprayed thrice during the flowering period. The materials were manually harvested at yellow-ripe stage. Resistance trait recorded was disease severity, i.e. percent ergot sclerotia in grain by weight. Mean ergot severity ranged from 2.29 to 4.08% for the five populations across environments. Significant genotypic variation (P < 0.01) due to FSF and FSF x environment interaction was observed within each population. Genotypic variation within all populations was higher than that among five populations. All populations showed high estimates of heritability (0.72-0.89). The study indicated that the evaluated OP populations are rich reservoirs of genetic variation that should also be used in hybrid breeding. Recurrent selection to further improve ergot resistance should be successful. PMID:18797841

  12. Simultaneous-integrated boost intensity-modulated radiation therapy (SIB-IMRT) in the treatment of early-stage left-sided breast carcinoma

    SciTech Connect

    Singla, Rajanish; King, Stephanie C.; Albuquerque, Kevin . E-mail: kalbuqu@lumc.edu; Creech, Steve M.S.; Dogan, Nesrin

    2006-10-01

    We assessed the feasibility and impact of simultaneous-integrated boost intensity-modulated radiation therapy (SIB-IMRT) in the treatment of left breast carcinoma and compared target coverage and normal tissue doses with SIB-IMRT and 3-dimensional (3D) conformal RT using opposed tangential fields. For each of 10 patients with early-stage left-sided invasive breast carcinoma, 5 plans were generated; the first 4 were 3D conformal opposed tangential fields-2 with wedges, 2 with compensators and either photon or electron boost. A dose of 50.4 Gy in 28 fractions was prescribed to the left breast and an additional 16 Gy in 8 fractions to the lumpectomy bed. When compared to the tangential plans, SIB-IMRT maintained coverage (V{sub 95%}) to the left breast and lumpectomy bed without significantly increasing the left breast maximum dose. SIB-IMRT was able to reduce the lung mean dose, maximum dose, and the V{sub 20} by 55-104 cGy, 983-1298 cGy (p < 0.001), and 3.7-4.4%, respectively. In addition, SIB-IMRT reduced the maximum heart dose by 1032-1173 cGy and contralateral breast dose was increased (although p = NS). The mean and maximum dose to the unspecified tissues was also significantly reduced by 81-88 cGy and 516-942 cGy, respectively. SIB-IMRT resulted in a significant improvement in target dose conformality by up to 67%. Our findings that SIB-IMRT could improve dose conformality, reduce total treatment times, and reduce some of the normal structure doses presents it as an alternative technique for adjuvant breast radiotherapy; however this needs to be studied further in the clinic setting.

  13. Automatic derivation of earth observation products from satellite data within the Siberian Earth System Science Cluster (SIB-ESS-C)

    NASA Astrophysics Data System (ADS)

    Eberle, J.; Schmullius, C. C.

    2011-12-01

    The Siberian Earth System Science Cluster (SIB-ESS-C) established at the University of Jena (Germany) is a spatial data infrastructure implementing standards published by the Open Geospatial Consortium (OGC) and the International Organization for Standardization (ISO) aimed at providing researchers with focus on Siberia with the technical means for data discovery, data access, data publication and data analysis in work with earth observation data. At the current development stage the SIB-ESS-C system comprises a federated metadata catalogue accessible through the SIB-ESS-C Web Portal or from any OGC-CSW compliant client. The Web Portal also contains a simple map-like visualization component which is currently being extended to a comprehensive visualization and analysis tool. The visualization component enables users to overlay different dataset found during a catalogue search. All data products are accessible as Web Mapping, Web Feature or Web Coverage Services allowing users to directly incorporate the data into their application. New developments aims on automatic registration and processing of raw earth observation data to derive permanently earth observation products. A data registry system within a whole process system including process chains to implement algorithms is currently designed. This will be extended with a system to process these incoming data automatically and permanently, depending on registered algorithms. Algorithms should know which input data is necessary and registered data should know which algorithms could be executed on it. This paper describes current developments as well as future ideas to build up a usefull and userfriendly access to satellite data, algorithms and therefrom derived products with state of the art web technologies and standards of the OGC.

  14. Two-locus admixture linkage analysis of bipolar and unipolar affective disorder supports the presence of susceptibility loci on chromosomes 11p15 and 21q22

    SciTech Connect

    Smyth, C.; Kalsi, G.; O`Neill, J.

    1997-02-01

    Following a report of a linkage study that yielded evidence for a susceptibility locus for bipolar affective disorder on the long arm of chromosome 21, we studied 23 multiply affected pedigrees collected from Iceland and the UK, using the markers PFKL, D21S171, and D21S49. Counting only bipolar cases as affected, a two-point LOD of 1.28 was obtained using D21S171 ({theta} = 0.01, {alpha} = 0.35), with three Icelandic families producing LODs of 0.63, 0.62, and 1.74 (all at {theta} = 0.0). Affected sib pair analysis demonstrated increased allele sharing at D21S171 (P = 0.001) when unipolar cases were also considered affected. The same set of pedigrees had previously been typed for a tyrosine hydroxylase gene (TH) polymorphism at 11p15 and had shown some moderate evidence for linkage. When information from TH and the 21q markers was combined in a two-locus admixture analysis, an overall admixture LOD of 3.87 was obtained using the bipolar affection model. Thus the data are compatible with the hypothesis that a locus at or near TH influences susceptibility in some pedigrees, while a locus near D21S171 is active in others. Similar analyses in other datasets should be carried out to confirm or refute our tentative finding. 66 refs., 3 tabs.

  15. Magnetic and structural properties of ferromagnetic Fe5PB2 and Fe5SiB2 and effects of Co and Mn substitutions

    DOE PAGESBeta

    McGuire, Michael A.; Parker, David S.

    2015-10-22

    Crystallographic and magnetic properties of Fe5PB2, Fe4CoPB2, Fe4MnPB2, Fe5SiB2, Fe4CoSiB2, and Fe4MnSiB2 are reported. All adopt the tetragonal Cr5B3 structure-type and are ferromagnetic at room temperature with easy axis of magnetization along the c-axis. The spin reorientation in Fe5SiB2 is observed as an anomaly in the magnetization near 170 K, and is suppressed by substitution of Co or Mn for Fe. The silicides are found to generally have larger magnetic moments than the phosphides, but the data suggests smaller magnetic anisotropy in the silicides. Cobalt substitution reduces the Curie temperatures by more than 100 K and ordered magnetic moments bymore » 16-20%, while manganese substitution has a much smaller effect. This suggests Mn moments align ferromagnetically with the Fe and that Co does not have an ordered moment in these structures. Anisotropic thermal expansion is observed in Fe5PB2 and Fe5SiB2, with negative thermal expansion seen along the c-axis of Fe5SiB2. First principles calculations of the magnetic properties of Fe5SiB2 and Fe4MnSiB2 are reported. The results, including the magnetic moment and anisotropy, and are in good agreement with experiment.« less

  16. A global climatology of albedo, roughness length and stomatal resistance for atmospheric general circulation models as represented by the Simple Biosphere Model (SiB)

    NASA Technical Reports Server (NTRS)

    Dorman, J. L.; Sellers, P. J.

    1989-01-01

    Components of the Simple Biosphere Model (SiB) of Sellers et al. (1986) were used to generate global monthly fields of surface albedo (0.4-4.0 microns), roughness length and minimum surface (stomatal) resistance. SiB consists of three submodels which describe the roles of radiative transfer, turbulent transfer and surface resistance in determining the energy balance of the vegetated land surface. These three submodels were detached from SiB and used on the SiB parameter set (total and green leaf area index, leaf angle orientation, canopy dimensions, etc.) to calculate global monthly fields of albedo, roughness length and minimum stomatal resistance at 1 x 1 deg resolution. Time series of various parameters are also displayed for each vegetation type for specified grid points. The SiB results compare reasonably well with appropriate measurements obtained from the literature and have the additional merit of being mutually consistent; the three submodels use many common parameters, which ensures that, for each grid area, the calculated surface properties are closely interrelated as is the case in nature. The derived fields provide a check on the operation of the submodels and the correctness of the parameter set. They can also be used as prescribed fields for GCMs that do not have biophysically based land surface parameterizations.

  17. Magnetic and structural properties of ferromagnetic Fe5PB2 and Fe5SiB2 and effects of Co and Mn substitutions

    NASA Astrophysics Data System (ADS)

    McGuire, Michael A.; Parker, David S.

    2015-10-01

    Crystallographic and magnetic properties of Fe5PB2, Fe4CoPB2, Fe4MnPB2, Fe5SiB2, Fe4CoSiB2, and Fe4MnSiB2 are reported. All adopt the tetragonal Cr5B3 structure-type and are ferromagnetic at room temperature with easy axis of magnetization along the c-axis. The spin reorientation in Fe5SiB2 is observed as an anomaly in the magnetization near 170 K and is suppressed by substitution of Co or Mn for Fe. The silicides are found to generally have larger magnetic moments than the phosphides, but the data suggest smaller magnetic anisotropy in the silicides. Cobalt substitution reduces the Curie temperatures by more than 100 K and ordered magnetic moments by 16%-20%, while manganese substitution has a much smaller effect. This suggests Mn moments align ferromagnetically with the Fe and that Co does not have an ordered moment in these structures. Anisotropic thermal expansion is observed in Fe5PB2 and Fe5SiB2, with negative thermal expansion seen along the c-axis of Fe5SiB2. First principles calculations of the magnetic properties of Fe5SiB2 and Fe4MnSiB2 are reported. The results, including the magnetic moment and anisotropy, are in good agreement with experiment.

  18. Pairing effects in nuclear dynamic

    NASA Astrophysics Data System (ADS)

    Lacroix, Denis; Scamps, Guillaume; Tanimura, Yusuke

    2016-05-01

    In recent years, efforts have been made to account for super-fluidity in time-dependent mean-field description of nuclear dynamic [1-5]. Inclusion of pairing is important to achieve a realistic description of static properties of nuclei. Here,we show that pairing can also affect the nuclear motion. State of the art TDHF approach can describe from small to large amplitude collective motion as well as the collision between nuclei. Very recently, this microscopic approach has been improved to include pairing either in the BCS or HFB framework. Recent applications of the 3D TDHF + BCS (TDHF+BCS) model introduced in [4] will be presented. The role of super-fluidity on collective motion [6, 7], on one- and two-particle transfer [8] and on fission [9, 10] will be illustrated.

  19. Illegitimacy and sibship assignments in oil palm (Elaeis guineensis Jacq.) half-sib families using single locus DNA microsatellite markers.

    PubMed

    Hama-Ali, Emad Omer; Alwee, Sharifah Shahrul Rabiah Syed; Tan, Soon Guan; Panandam, Jothi Malar; Ling, Ho Chai; Namasivayam, Parameswari; Peng, Hoh Boon

    2015-05-01

    Oil palm breeding has been progressing very well in Southeast Asia, especially in Malaysia and Indonesia. Despite this progress, there are still problems due to the difficulty of controlled crossing in oil palm. Contaminated/illegitimate progeny has appeared in some breeding programs; late and failure of detection by the traditional method causes a waste of time and labor. The use of molecular markers improves the integrity of breeding programs in perennial crops such as oil palm. Four half-sib families with a total of 200 progeny were used in this study. Thirty polymorphic single locus DNA microsatellites markers were typed to identify the illegitimate individuals and to obtain the correct parental and progeny assignments by using the CERVUS and COLONY programs. Three illegitimate palms (1.5%) were found, and 16 loci proved to be sufficient for sibship assignments without parental genotypes by using the COLONY program. The pairwise-likelihood score (PLS) method was better for half-sib family assignments than the full likelihood (FL) method. PMID:25399079

  20. Effects of voltage on microstructure and oxidation resistance of SiB6-MoSi2 coating deposited by pulse arc discharge deposition

    NASA Astrophysics Data System (ADS)

    Zhang, Yong-Liang; Huang, Jian-Feng; Zhu, Kong-Jun; Cao, Li-Yun; Li, Cui-Yan; Zhou, Lei; Zhang, Bo-Ye; Kong, Wei-Hua; Zhang, Bo

    2015-06-01

    To protect carbon/carbon (C/C) composites against oxidation, a SiB6-MoSi2 coating was prepared by pulse arc discharge deposition (PADD). The influence of deposition voltage on arc discharge sintering ability, microstructure and oxidation resistance of the SiB6-MoSi2 coatings was investigated. Results show that the oxidation resistance of the coating is improved when the voltage increases from 350 to 450 V. The dense and good crystallization SiB6-MoSi2 coating was obtained with sufficient arc discharge sintering energy when the voltage is 450 V. And the multilayer coatings can protect C/C composites from oxidation in air at 1773 K for 164 h with a weight loss of 2.04%. The evaporation of the molten glass layer and MoO3 is the main reason for the failure of the multilayer coatings.

  1. Peripheral and spinal antihyperalgesic activity of SIB-1757, a metabotropic glutamate receptor (mGLUR(5)) antagonist, in experimental neuropathic pain in rats.

    PubMed

    Dogrul, A; Ossipov, M H; Lai, J; Malan, T P; Porreca, F

    2000-10-01

    Recent studies suggest a role of Group 1 metabotropic glutamate receptors in mediating the development of spinal hypersensitivity in some pain states. Here, the possible role of mGluR(5) receptors in experimental neuropathic pain elicited by ligation of spinal nerves (L(5)/L(6) spinal nerve ligation, SNL) was explored with SIB-1757, a selective mGluR(5) antagonist. SNL-induced tactile allodynia was detected by decreased paw withdrawal thresholds to probing with von Frey filaments and thermal hyperalgesia by decreased paw withdrawal latencies to radiant heat applied to the plantar aspect of the hindpaw. SIB-1757 was given by either intrathecal (i.th.), subcutaneous (s.c.) or intraplantar (i.pl.) injection. In SNL rats, i.th. SIB-1757 produced a partial reversal of tactile allodynia with a shallow dose-response curve ranging over three-orders of magnitude; SIB-1757 was inactive against allodynia when given systemically. SIB-1757 produced full reversal of thermal hyperalgesia in SNL rats following administration either spinally or locally to the injured paw; administration to the contralateral paw had no effect. SIB-1757 did not produce antinociception in either the SNL or sham-operated rats by any route. These data suggest a significant modulation of thermal hyperalgesia by mGluR(5) antagonists, consistent with reports that this receptor may be associated with afferent C-fibers. The less impressive effect seen on tactile allodynia, likely to be mediated by large fiber input, suggests that the observed modulation may be related to blockade of mGluR(5)-mediated spinal sensitization. These results do not support the involvement of these receptors in modulation of acute nociception but suggest the possibility of a role for Group I mGluRs in the mediation of aspects of neuropathic pain which may be associated with C-fiber inputs. PMID:10998562

  2. Stereo Pair, Pasadena, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This stereoscopic image pair is a perspective view that shows the western part of the city of Pasadena, California, looking north toward the San Gabriel Mountains. Portions of the cities of Altadena and La Canada Flintridge are also shown. The cluster of large buildings left of center, at the base of the mountains, is the Jet Propulsion Laboratory. This image shows the power of combining data from different sources to create planning tools to study problems that affect large urban areas. In addition to the well-known earthquake hazards, Southern California is affected by a natural cycle of fire and mudflows. Data shown in this image can be used to predict both how wildfires spread over the terrain and how mudflows are channeled down the canyons.

    The image was created from three datasets: the Shuttle Radar Topography Mission (SRTM) supplied the elevation, U. S. Geological Survey digital aerial photography provided the image detail, and the Landsat Thematic Mapper provided the color. The United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota, provided the Landsat data and the aerial photography. The image can be viewed in 3-D by viewing the left image with the right eye and the right image with the left eye (cross-eyed viewing), or by downloading and printing the image pair, and viewing them with a stereoscope.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration

  3. Familiality of Tourette Syndrome, Obsessive-Compulsive Disorder, and Attention-Deficit/Hyperactivity Disorder: Heritability Analysis in a Large Sib-Pair Sample

    ERIC Educational Resources Information Center

    Mathews, Carol A.; Grados, Marco A.

    2011-01-01

    Objective: Tourette syndrome (TS) is a neuropsychiatric disorder with a genetic component that is highly comorbid with obsessive-compulsive disorder (OCD) and attention deficit/hyperactivity disorder (ADHD). However, the genetic relations between these disorders have not been clearly elucidated. This study examined the familial relations among TS,…

  4. Pairing forces in nuclei

    SciTech Connect

    Chasman, R.R.

    1996-12-31

    In this contribution, the author mentions some features of pairing forces that are unique to nuclei and cover some areas of major interest in nuclear structure research, that involve pairing. At the level of most nuclear structure studies, nuclei are treated as consisting of two kinds of fermions (protons and neutrons) in a valence space with rather few levels. These features give rise to unique aspects of pairing forces in nuclei: (1) n-p pairing in T = 0 as well as the usual T = 1 pairing that is characteristic of like fermions; (2) a need to correct pairing calculations for the (1/N) effects that can typically be neglected in superconducting solids. An issue of current concern is the nature of the pairing interaction: several recent studies suggest a need for a density dependent form of the pairing interaction. There is a good deal of feedback between the questions of accurate calculations of pairing interactions and the form and magnitude of the pairing interaction. Finally, the authors discuss some many-body wave functions that are a generalization of the BCS wave function form, and apply them to a calculation of energy level spacings in superdeformed rotational bands.

  5. Matched-pair classification

    SciTech Connect

    Theiler, James P

    2009-01-01

    Following an analogous distinction in statistical hypothesis testing, we investigate variants of machine learning where the training set comes in matched pairs. We demonstrate that even conventional classifiers can exhibit improved performance when the input data has a matched-pair structure. Online algorithms, in particular, converge quicker when the data is presented in pairs. In some scenarios (such as the weak signal detection problem), matched pairs can be generated from independent samples, with the effect not only doubling the nominal size of the training set, but of providing the structure that leads to better learning. A family of 'dipole' algorithms is introduced that explicitly takes advantage of matched-pair structure in the input data and leads to further performance gains. Finally, we illustrate the application of matched-pair learning to chemical plume detection in hyperspectral imagery.

  6. Vortex pairs on surfaces

    SciTech Connect

    Koiller, Jair

    2009-05-06

    A pair of infinitesimally close opposite vortices moving on a curved surface moves along a geodesic, according to a conjecture by Kimura. We outline a proof. Numerical simulations are presented for a pair of opposite vortices at a close but nonzero distance on a surface of revolution, the catenoid. We conjecture that the vortex pair system on a triaxial ellipsoid is a KAM perturbation of Jacobi's geodesic problem. We outline some preliminary calculations required for this study. Finding the surfaces for which the vortex pair system is integrable is in order.

  7. Locating human quantitative trait loci: guidelines for the selection of sibling pairs for genotyping.

    PubMed

    Eaves, L; Meyer, J

    1994-09-01

    Simulation studies were conducted to assess the relative merits of different nonrandom sampling strategies for the selection of sibling pairs for genotyping in the attempt to locate individual loci (QTLs) contributing to variation in human quantitative traits. For a constant amount of variation contributed by a QTL (25% of the total) the frequencies and dominance relationships of a trait increasing allele were varied. Three strategies for selection of pairs for genotyping were based on the phenotypic values of the siblings: "Concordant sib pairs" (CSP) are pairs in which both individuals exceed a given threshold value; "discordant sib pairs" (DSP) are pairs in which one member exceeds a given upper threshold and the other is below a specified lower threshold; and "most similar pairs" (MSP) are pairs selected for falling below a specified percentile ranking of the within-pair mean square for the quantitative trait. Tests for linkage with markers at 1, 2, 5, 10, and 20 cM from each of the QTLs were conducted for each of the selected samples and compared with tests based on the regression, in the entire sample, of within pair variation on the proportion of alleles identical by descent (IBD) at each marker locus. Tests for the effect of the increasing allele at the QTL ("candidate gene") were also conducted for the DSP pairs. No single nonrandom selection procedure yields as much as half the information realized in the total sample. However, a combined strategy which involves genotyping the 5% of MSP and DSP for the upper and lower quintiles of values of the quantitative trait (a further 3% of the sample approximately) yields lod scores which are usually more than 65% of the values realized for the entire sample. Tests comparing the proportion of increasing alleles in high- and low-scoring siblings from DSP samples are uniformly very powerful for detecting candidate loci. Even when it is not possible to measure the entire range of the phenotype with uniform precision

  8. Response of a gall wasp community to genetic variation in the host plant Quercus crispula: a test using half-sib families

    NASA Astrophysics Data System (ADS)

    Ito, Masato; Ozaki, Kenichi

    2005-02-01

    The structure of a herbivore community may change consistently along the genetic cline of a host plant, change at particular points along the cline, or respond independently of the cline. To reveal such relationships between a gall wasp community and genetic variation in the host plant Quercus crispula, we examined patterns in the species richness and abundance of gall wasps along a genetic cline of the host plant, using 12 half-sib families from six different regions. The genetic relationships among the half-sib families of Q. crispula were quantified on the basis of leaf morphology, which represented a morphological cline from leaves typical of Q. crispula to leaves resembling another oak species, Q. dentata. The morphological cline could be regarded as a genetic cline caused by a history of hybridization with Q. dentata. The mean numbers of gall types varied among the half-sib families, but did not show a consistent increase or decrease along the genetic cline. This pattern could be explained by the fact that responses to host plant variation differed among the gall wasp species. The half-sib families were classified into three groups based on an ordination analysis of the species composition of the gall wasp community that to some extent also reflected the genetic cline of Q. crispula. This suggests that the species composition of gall wasps changed intermittently along the genetic cline, rather than gradually and consistently along the cline.

  9. Vaccination of full-sib channel catfish families against enteric septicemia of catfish with an oral live attenuated Edwardsiella ictaluri vaccine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study evaluated the efficacy of an oral live-attenuated Edwardsiella ictaluri vaccine against enteric septicemia of catfish in 20 full-sib fingerling channel catfish families. Each family was split into vaccinated and non-vaccinated groups. The vaccine was delivered orally by feeding fish diet...

  10. Enabling the development of Community Extensions to GI-cat - the SIB-ESS-C case study

    NASA Astrophysics Data System (ADS)

    Bigagli, L.; Meier, N.; Boldrini, E.; Gerlach, R.

    2009-04-01

    GI-cat is a Java software package that implements discovery and access services for disparate geospatial resources. An instance of GI-cat provides a single point of service for querying and accessing remote, as well as local, heterogeneous sources of geospatial information, either through standard interfaces, or taking advantage of GI-cat advanced features, such as incremental responses, query feedback, etc. GI-cat supports a number of de-iure and de-facto standards, but can also be extended to additional community catalog/inventory services, by defining appropriate mediation components. The GI-cat and the SIB-ESS-C development teams collaborated in the development of a mediator to the Siberian Earth Science System Cluster (SIB-ESS-C), a web-based infrastructure to support the communities of environmental and Earth System research in Siberia. This activity resulted in the identification of appropriate technologies and internal mechanisms supporting the development of GI-cat extensions, that are the object of this work. GI-cat is actually built up of a modular framework of SOA components, that can be variously arranged to fit the needs of a community of users. For example, a particular GI-cat instance may be configured to provide discovery functionalities onto an OGC WMS; or to adapt a THREDDS catalog to the standard OGC CSW interface; or to merge a number of CDI repositories into a single, more efficient catalog. The flexibility of GI-cat framework is achieved thanks to its design, that follows the Tree of Responsibility (ToR) pattern and the Uniform Pipe and Filter architectural style. This approach allows the building of software blocks that can be flexibly reused and composed in multiple ways. In fact, the components that make up any GI-cat configuration all implement two common interfaces (i.e. IChainNode and ICatalogService), that support chaining one component to another . Hence, it would suffice to implement those interfaces (plus an appropriate factory

  11. HLA non-class II genes may confer type I diabetes susceptibility in a Mapuche (Amerindian) affected family.

    PubMed

    Pérez-Bravo, Francisco; Martinez-Laso, Jorge; Martin-Villa, Jose M; Moscoso, Juan; Moreno, Almudena; Serrano-Vela, Juan I; Zamora, Jorge; Asenjo, Silvia; Gleisner, Andrea; Arnaiz-Villena, Antonio

    2006-01-01

    A rare case of type I diabetes is studied in an Amerindian (Mapuche) family from Chile, analyzing glutamic acid decarboxylase, islet-cell autoantibodies and human leukocyte antigen (HLA) genes. The affected sib is the only one that has one specific HLA haplotype combination that differs from the other sibs only in the HLA class I genes. It is concluded that HLA diabetes susceptibility factors may be placed outside the class II region or even that susceptibility factors do not exist in the HLA region in this Amerindian family. PMID:16473308

  12. Cooper Pairs in Insulators?!

    ScienceCinema

    James Valles

    2010-01-08

    Nearly 50 years elapsed between the discovery of superconductivity and the emergence of the microscopic theory describing this zero resistance state. The explanation required a novel phase of matter in which conduction electrons joined in weakly bound pairs and condensed with other pairs into a single quantum state. Surprisingly, this Cooper pair formation has also been invoked to account for recently uncovered high-resistance or insulating phases of matter. To address this possibility, we have used nanotechnology to create an insulating system that we can probe directly for Cooper pairs. I will present the evidence that Cooper pairs exist and dominate the electrical transport in these insulators and I will discuss how these findings provide new insight into superconductor to insulator quantum phase transitions. 

  13. Pair contact process with diffusion of pairs

    NASA Astrophysics Data System (ADS)

    Santos, F. L.; Dickman, Ronald; Fulco, U. L.

    2011-03-01

    The pair contact process (PCP) is a nonequilibrium stochastic model which, like the basic contact process (CP), exhibits a phase transition to an absorbing state. The two models belong to the directed percolation (DP) universality class, despite the fact that the PCP possesses infinitely many absorbing configurations whereas the CP has but one. The critical behavior of the PCP with hopping by particles (PCPD) is as yet unclear. Here we study a version of the PCP in which nearest-neighbor particle pairs can hop but individual particles cannot. Using quasistationary simulations for three values of the diffusion probability (D = 0.1, 0.5 and 0.9), we find convincing evidence of DP-like critical behavior.

  14. Evidence of major genes affecting stress response in rainbow trout using Bayesian methods of complex segregation analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a first step towards the genetic mapping of quantitative trait loci (QTL) affecting stress response variation in rainbow trout, we performed complex segregation analyses (CSA) fitting mixed inheritance models of plasma cortisol using Bayesian methods in large full-sib families of rainbow trout. ...

  15. Electron pairing without superconductivity.

    PubMed

    Cheng, Guanglei; Tomczyk, Michelle; Lu, Shicheng; Veazey, Joshua P; Huang, Mengchen; Irvin, Patrick; Ryu, Sangwoo; Lee, Hyungwoo; Eom, Chang-Beom; Hellberg, C Stephen; Levy, Jeremy

    2015-05-14

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances-paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity. PMID:25971511

  16. Electron pairing without superconductivity

    NASA Astrophysics Data System (ADS)

    Cheng, Guanglei; Tomczyk, Michelle; Lu, Shicheng; Veazey, Joshua P.; Huang, Mengchen; Irvin, Patrick; Ryu, Sangwoo; Lee, Hyungwoo; Eom, Chang-Beom; Hellberg, C. Stephen; Levy, Jeremy

    2015-05-01

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity.

  17. Electron pairing without superconductivity

    NASA Astrophysics Data System (ADS)

    Levy, Jeremy

    Strontium titanate (SrTiO3) is the first and best known superconducting semiconductor. It exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to that of high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. Despite sustained interest for 50 years, direct experimental insight into the nature of electron pairing in SrTiO3 has remained elusive. Here we perform transport experiments with nanowire-based single-electron transistors at the interface between SrTiO3 and a thin layer of lanthanum aluminate, LaAlO3. Electrostatic gating reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical pairing field Bp of about 1-4 tesla, an order of magnitude larger than the superconducting critical magnetic field. For magnetic fields below Bp, these resonances are insensitive to the applied magnetic field; for fields in excess of Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as 900 millikelvin, well above the superconducting transition temperature (about 300 millikelvin). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by a model involving an attractive Hubbard interaction that describes real-space electron pairing as a precursor to superconductivity. Support from AFOSR, ONR, ARO, NSF, DOE and NSSEFF is gratefully acknowledged.

  18. Treatment of retinal detachment with an encircling band and buckle implant: A comparative pilot study between poly (styrene-b-isobutylene-b-styrene) (SIBS) and trimethyl terminated polydimethylsiloxane (PDMS)

    NASA Astrophysics Data System (ADS)

    Aguilar, Mariela; Yamamoto, Hideo; Espana, Edgar; Acosta, Ana Carolina; Orozco, Marcia; Aly, Mohamed; Arrieta, Esdras; Hernandez, Eleut; Martin, John; Dubovy, Sander; Smiddy, William; Pinchuk, Leonard; Parel, Jean-Marie

    2006-02-01

    Purpose: To demonstrate the biocompatibility of SIBS implants as compared to PDMS implants in the treatment of retinal detachment in New Zealand White (NZW) rabbit model. 1,2 Introduction: Scleral encircling bands, fixation rings and buckles are utilized for closure of retinal breaks and retina reattachment. The FDA approved PDMS-implant is associated with several post-operative complications, involving thick-fibrotic encapsulations. SIBS, an elastomeric triblock copolymer, was recently FDA approved for use in a cardiovascular drug eluting stent (TAXUS TM, Boston Scientific Corp., MA) and showed excellent biocompatibility and slow drug release capability. Materials and Methods: SIBS (9-mol%-styrene) implants were fabricated (InnFocus LLC, USA) to match PDMS implants (Labtician, Inc, Canada) dimensions. 5 NZW rabbits received SIBS and 4, PDMS-implants. Post-operative exam sequence: day 1 and 2, week 1, 2, 3, 4 and 6, and monthly thereafter for up to 1 year. Anatomohistopathology exams sequence: one SIBS animal at 6 weeks and one animal of each treatment group at 3 and 6-months, and two at 12-months. Results: SIBS compared to PDMS animals exhibited less inflammation and a better buckling effect during the first 6 weeks. At POD 9 months, the conjunctival injection in the SIBS rabbit was none as opposed to the PDMS value and the buckling effect for both groups were equal. There were no visible signs of encapsulation with SIBS. There were no infections in the 9 animals and none of the implants extruded thus far (<10 months). Conclusion: SIBS encircling bands, sleeves, and buckle implants are well tolerated in the rabbit model.

  19. Paired Straight Hearth Furnace

    SciTech Connect

    2009-04-01

    This factsheet describes a research project whose goals are to design, develop, and evaluate the scalability and commercial feasibility of the PSH Paired Straight Hearth Furnace alternative ironmaking process.

  20. Cooper Pair Insulators

    NASA Astrophysics Data System (ADS)

    Valles, James

    One of the recent advances in the field of the Superconductor to Insulator Transition (SIT) has been the discovery and characterization of the Cooper Pair Insulator phase. This bosonic insulator, which consists of localized Cooper pairs, exhibits activated transport and a giant magneto-resistance peak. These features differ markedly from the weakly localized transport that emerges as pairs break at a ``fermionic'' SIT. I will describe how our experiments on films nano-patterned with a nearly triangular array of holes have enabled us to 1) distinguish bosonic insulators from fermionic insulators, 2) show that Cooper pairs, rather than quasi-particles dominate the transport in the Cooper Pair insulator phase, 3) demonstrate that very weak, sub nano-meter thickness inhomogeneities control whether a bosonic or fermionic insulator forms at an SIT and 4) reveal that Cooper pairs disintegrate rather than becoming more tightly bound deep in the localized phase. We have also developed a method, using a magnetic field, to tune flux disorder reversibly in these films. I will present our latest results on the influence of magnetic flux disorder and random gauge fields on phenomena near bosonic SITs. This work was performed in collaboration with M. D. Stewart, Jr., Hung Q. Nguyen, Shawna M. Hollen, Jimmy Joy, Xue Zhang, Gustavo Fernandez, Jeffrey Shainline and Jimmy Xu. It was supported by NSF Grants DMR 1307290 and DMR-0907357.

  1. A dosimetric comparison of 3D-CRT, IMRT, and static tomotherapy with an SIB for large and small breast volumes

    SciTech Connect

    Michalski, Andrea; Atyeo, John; Cox, Jennifer; Rinks, Marianne; Morgia, Marita; Lamoury, Gillian

    2014-07-01

    Radiation therapy to the breast is a complex task, with many different techniques that can be employed to ensure adequate dose target coverage while minimizing doses to the organs at risk. This study compares the dose planning outcomes of 3 radiation treatment modalities, 3 dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and static tomotherapy, for left-sided whole-breast radiation treatment with a simultaneous integrated boost (SIB). Overall, 20 patients with left-sided breast cancer were separated into 2 cohorts, small and large, based on breast volume. Dose plans were produced for each patient using 3D-CRT, IMRT, and static tomotherapy. All patients were prescribed a dose of 45 Gy in 20 fractions to the breast with an SIB of 56 Gy in 20 fractions to the tumor bed and normalized so that D{sub 98%} > 95% of the prescription dose. Dosimetric comparisons were made between the 3 modalities and the interaction of patient size. All 3 modalities offered adequate planning target volume (PTV) coverage with D{sub 98%} > 95% and D{sub 2%} < 107%. Static tomotherapy offered significantly improved (p = 0.006) dose homogeneity to the PTV{sub boost} {sub eval} (0.079 ± 0.011) and breast minus the SIB volume (Breast{sub SIB}) (p < 0.001, 0.15 ± 0.03) compared with the PTV{sub boost} {sub eval} (0.085 ± 0.008, 0.088 ± 0.12) and Breast{sub SIB} (0.22 ± 0.05, 0.23 ± 0.03) for IMRT and 3D-CRT, respectively. Static tomotherapy also offered statistically significant reductions (p < 0.001) in doses to the ipsilateral lung mean dose of 6.79 ± 2.11 Gy compared with 7.75 ± 2.54 Gy and 8.29 ± 2.76 Gy for IMRT and 3D-CRT, respectively, and significantly (p < 0.001) reduced heart doses (mean = 2.83 ± 1.26 Gy) compared to both IMRT and 3D-CRT (mean = 3.70 ± 1.44 Gy and 3.91 ± 1.58 Gy). Static tomotherapy is the dosimetrically superior modality for the whole breast with an SIB compared with IMRT and 3D-CRT. IMRT is superior to 3D

  2. Electron Pairing Without Superconductivity

    NASA Astrophysics Data System (ADS)

    Levy, Jeremy; Cheng, G.; Tomczyk, M.; Lu, S.; Veazey, J. P.; Huang, M.; Irvin, P.; Ryu, S.; Lee, H.; Eom, C.-B.; Hellberg, C. S.

    2015-03-01

    Strontium titanate (SrTiO3) exhibits an extremely low carrier density threshold for superconductivity, and possesses a phase diagram similar to high-temperature superconductors--two factors that suggest an unconventional pairing mechanism. We describe transport experiments with nanowire-based quantum dots localized at the interface between SrTiO3 and LaAlO3. Electrostatic gating of the quantum dot reveals a series of two-electron conductance resonances--paired electron states--that bifurcate above a critical magnetic field Bp 1-4 Tesla, an order of magnitude larger than the superconducting critical magnetic field. For B Bp, the resonances exhibit a linear Zeeman-like energy splitting. Electron pairing is stable at temperatures as high as T = 900 mK, far above the superconducting transition temperature (Tc 300 mK). These experiments demonstrate the existence of a robust electronic phase in which electrons pair without forming a superconducting state. Key experimental signatures are captured by an attractive-U Hubbard model that describes real-space electron pairing as a precursor to superconductivity. This work was supported by ARO MURI W911NF-08-1-0317 (J.L.), AFOSR MURI FA9550-10-1-0524 (C.-B.E., J.L.) and FA9550-12-1-0342 (C.-B.E.), and grants from the National Science Foundation DMR-1104191 (J.L.), DMR.

  3. PREFACE: III All-Russian Scientific and Practical Conference on Innovations in Non-Destructive Testing (SibTest 2015)

    NASA Astrophysics Data System (ADS)

    2016-01-01

    This issue of the journal is devoted to the research and studies presented at the III All-Russian Scientific and Practical Conference on Innovations in Non-Destructive Testing SibTest. The conference was held in Altai, Russia, on 27-31 July 2015. The conference brought together experts from different countries and organizations who had a great opportunity to share knowledge during oral and poster presentations and to initiate discussions on topics that are of interest to the conference attendees. The conference aimed to discuss innovative methods and the application of advanced technologies in non-destructive testing. The conference also attempted to bring together university, academic and industrial science, to expand the co-operation of scientists from different countries in research and development and the commercialization of innovative technologies in non-destructive testing. The key themes of the conference were: ultrasonic and acoustic testing; electromagnetic and thermal testing; various types of radiation non-destructive testing; passive and active testing techniques. The conference organizers are the Institute of Non-Destructive Testing, Tomsk Polytechnic University, with the assistance of the Russian Society for Non-Destructive Testing and Technical Diagnostics, Institute of Strength Physics and Materials Science, Siberian Branch of the Russian Academy of Sciences, National Research Tomsk State University, Moscow State Institute of Radio Engineering, Electronics and Automation.

  4. Bias in the prediction of genetic gain due to mass and half-sib selection in random mating populations

    PubMed Central

    2009-01-01

    The prediction of gains from selection allows the comparison of breeding methods and selection strategies, although these estimates may be biased. The objective of this study was to investigate the extent of such bias in predicting genetic gain. For this, we simulated 10 cycles of a hypothetical breeding program that involved seven traits, three population classes, three experimental conditions and two breeding methods (mass and half-sib selection). Each combination of trait, population, heritability, method and cycle was repeated 10 times. The predicted gains were biased, even when the genetic parameters were estimated without error. Gain from selection in both genders is twice the gain from selection in a single gender only in the absence of dominance. The use of genotypic variance or broad sense heritability in the predictions represented an additional source of bias. Predictions based on additive variance and narrow sense heritability were equivalent, as were predictions based on genotypic variance and broad sense heritability. The predictions based on mass and family selection were suitable for comparing selection strategies, whereas those based on selection within progenies showed the largest bias and lower association with the realized gain. PMID:21637512

  5. Magnetic properties of FeCu (3 d transition metals) SiB alloys with fine grain structure

    SciTech Connect

    Sawa, T. ); Takahashi, Y. )

    1990-05-01

    Soft magnetic properties were investigated together with crystallization process and grain size for FeCu (3{ital d} transition metals) SiB alloys with fine grains. They were rapidly quenched from the melt to achieve amorphous states and then annealed above their crystallization temperatures. In the group of 3{ital d} transition metals studied, low magnetic core loss at high frequency was obtained for V-substituted Fe-based alloys, because only a bcc Fe solid solution with diameter of about 20 nm precipitated. On the other hand, Cr- or Mn-substituted alloys could not be attained with good soft magnetic properties because of the existence of Fe-metalloid compounds besides the bcc phase by annealing above their crystallization temperatures. The effect of grain size on the soft magnetic properties is more prominent at lower frequency. Diffraction peaks which are characteristics of an ordered phase (DO{sub 3}) are observed, which is the origin of excellent soft magnetic properties in FeAlSi alloys.

  6. A revised land surface parameterization (SiB2) for GCMs. Part III: The greening of the Colorado State University general circulation model

    SciTech Connect

    Randall, D.A.; Dazlich, D.A.; Zhang, C.; Denning, A.S.

    1996-04-01

    SiB2, the second-generation land-surface parameterization developed by Sellers et al., has been incorporated into the Colorado State University general circulation model and tested in multidecade simulations. The control run uses a {open_quotes}bucket{close_quotes} hydrology but employs the same surface albedo and surface roughness distributions as the SiB2 run. Results show that SiB2 leads to a general warming of the continents, as evidenced in the ground temperature, surface air temperature, and boundary-layer-mean potential temperature. The surface sensible heat flux increases and the latent heat flux decreases. This warming occurs virtually everywhere but is most spectacular over Siberia in winter. Precipitation generally decreases over land but increases in the monsoon regions, especially the Amazon basin in January and equatorial Africa and Southeast Asia in July. Evaporation decreases considerably, especially in dry regions such as the Sahara. The excess of precipitation over evaporation increases in the monsoon regions. The precipitable water (vertically integrated water vapor content) generally decreases over land but increases in the monsoon regions. The mixing ratio of the boundary-layer air decreases over nearly all continental areas, however, including the monsoon regions. The net surface longwave cooling of the surface increases quite dramatically over land, in accordance with the increased surface temperatures and decreased cloudiness. The solar radiation absorbed at the ground also increases. SiB2 has modest effects on the simulated general circulation of the atmosphere. Its most important impacts on the model are to improve the simulations of surface temperature and snow cover and to enable the simulation of the net rate of terrestrial carbon assimilation. 39 refs., 23 figs., 5 tabs.

  7. Supernovae in paired galaxies

    NASA Astrophysics Data System (ADS)

    Nazaryan, T. A.; Petrosian, A. R.; Hakobyan, A. A.; Adibekyan, V. Zh.; Kunth, D.; Mamon, G. A.; Turatto, M.; Aramyan, L. S.

    2014-07-01

    We investigate the influence of close neighbor galaxies on the properties of supernovae (SNe) and their host galaxies using 56 SNe located in pairs of galaxies with different levels of star formation (SF) and nuclear activity. The mean distance of type II SNe from nuclei of hosts is greater by about a factor of 2 than that of type Ibc SNe. The distributions and mean distances of SNe are consistent with previous results compiled with the larger sample. For the first time it is shown that SNe Ibc are located in pairs with significantly smaller difference of radial velocities between components than pairs containing SNe Ia and II. We consider this as a result of higher star formation rate (SFR) of these closer systems of galaxies.

  8. Applications of balanced pairs

    NASA Astrophysics Data System (ADS)

    Li, HuanHuan; Wang, JunFu; Huang, ZhaoYong

    2016-05-01

    Let $(\\mathscr{X}$, $\\mathscr{Y})$ be a balanced pair in an abelian category. We first introduce the notion of cotorsion pairs relative to $(\\mathscr{X}$, $\\mathscr{Y})$, and then give some equivalent characterizations when a relative cotorsion pair is hereditary or perfect. We prove that if the $\\mathscr{X}$-resolution dimension of $\\mathscr{Y}$ (resp. $\\mathscr{Y}$-coresolution dimension of $\\mathscr{X}$) is finite, then the bounded homotopy category of $\\mathscr{Y}$ (resp. $\\mathscr{X}$) is contained in that of $\\mathscr{X}$ (resp. $\\mathscr{Y}$). As a consequence, we get that the right $\\mathscr{X}$-singularity category coincides with the left $\\mathscr{Y}$-singularity category if the $\\mathscr{X}$-resolution dimension of $\\mathscr{Y}$ and the $\\mathscr{Y}$-coresolution dimension of $\\mathscr{X}$ are finite.

  9. String pair production in non homogeneous backgrounds

    NASA Astrophysics Data System (ADS)

    Bolognesi, S.; Rabinovici, E.; Tallarita, G.

    2016-04-01

    We consider string pair production in non homogeneous electric backgrounds. We study several particular configurations which can be addressed with the Euclidean world-sheet instanton technique, the analogue of the world-line instanton for particles. In the first case the string is suspended between two D-branes in flat space-time, in the second case the string lives in AdS and terminates on one D-brane (this realizes the holographic Schwinger effect). In some regions of parameter space the result is well approximated by the known analytical formulas, either the particle pair production in non-homogeneous background or the string pair production in homogeneous background. In other cases we see effects which are intrinsically stringy and related to the non-homogeneity of the background. The pair production is enhanced already for particles in time dependent electric field backgrounds. The string nature enhances this even further. For spacial varying electrical background fields the string pair production is less suppressed than the rate of particle pair production. We discuss in some detail how the critical field is affected by the non-homogeneity, for both time and space dependent electric field backgrouds. We also comment on what could be an interesting new prediction for the small field limit. The third case we consider is pair production in holographic confining backgrounds with homogeneous and non-homogeneous fields.

  10. Recurrence of achondrogenesis type 2 in sibs: Additional evidence for germline mosaicism.

    PubMed

    Comstock, Jessica M; Putnam, Angelica R; Sangle, Nikhil; Lowichik, Amy; Rose, Nancy C; Opitz, John M

    2010-07-01

    Achondrogenesis Type II (ACG2) is a lethal skeletal disorder caused by a dominant mutation in the type II collagen gene (COL2A1). Familial cases have been reported, suggesting both germline and somatic mosaicism. We report on two pregnancies from the same couple with gross, radiologic, and microscopic findings of ACG2. Molecular analysis of the second infant demonstrated heterozygosity for a c.2303G > A transition (p.Gly768Asp) in exon 33 of the COL2A1 gene. Although this mutation could not be proven by molecular studies in the first infant, identical findings in two affected pregnancies support germline mosaicism as the cause of ACG2 in this family. PMID:20583175

  11. Two sibs with Wiedemann-Rautenstrauch syndrome: possibilities of prenatal diagnosis by ultrasound.

    PubMed Central

    Castiñeyra, G; Panal, M; Lopez Presas, H; Goldschmidt, E; Sánchez, J M

    1992-01-01

    A girl with Wiedemann-Rautenstrauch syndrome was born to a non-consanguineous couple. During the pregnancy, growth retardation particularly in the biparietal and abdominal diameters but not the femoral length was detected through serial ultrasound scans. When the woman became pregnant again, in spite of having been assessed as having a 25% risk of recurrence, the prenatal findings seen in her previous pregnancy led us to suggest sequential echography and a similar pattern of growth retardation was shown. After termination, the male fetus was found to be affected by Wiedemann-Rautenstrauch syndrome. This case shows that ultrasound examination can be a useful tool in the prenatal diagnosis of this rare, autosomal recessive syndrome. Images PMID:1619643

  12. Genome-wide association study and meta-analysis find that over 40 loci affect risk of type 1 diabetes.

    PubMed

    Barrett, Jeffrey C; Clayton, David G; Concannon, Patrick; Akolkar, Beena; Cooper, Jason D; Erlich, Henry A; Julier, Cécile; Morahan, Grant; Nerup, Jørn; Nierras, Concepcion; Plagnol, Vincent; Pociot, Flemming; Schuilenburg, Helen; Smyth, Deborah J; Stevens, Helen; Todd, John A; Walker, Neil M; Rich, Stephen S

    2009-06-01

    Type 1 diabetes (T1D) is a common autoimmune disorder that arises from the action of multiple genetic and environmental risk factors. We report the findings of a genome-wide association study of T1D, combined in a meta-analysis with two previously published studies. The total sample set included 7,514 cases and 9,045 reference samples. Forty-one distinct genomic locations provided evidence for association with T1D in the meta-analysis (P < 10(-6)). After excluding previously reported associations, we further tested 27 regions in an independent set of 4,267 cases, 4,463 controls and 2,319 affected sib-pair (ASP) families. Of these, 18 regions were replicated (P < 0.01; overall P < 5 × 10(-8)) and 4 additional regions provided nominal evidence of replication (P < 0.05). The many new candidate genes suggested by these results include IL10, IL19, IL20, GLIS3, CD69 and IL27. PMID:19430480

  13. A syndrome of insulin resistance resembling leprechaunism in five sibs of consanguineous parents.

    PubMed Central

    al-Gazali, L I; Khalil, M; Devadas, K

    1993-01-01

    Leprechaunism is a rare autosomal recessive disorder associated with extreme insulin resistance with paradoxical hypo-glycaemia. It is characterised by prenatal and postnatal growth retardation, reduced subcutaneous tissue, coarse features, acanthosis nigricans, enlarged genitalia, and death in the first year of life. Defects in both the insulin receptor and postreceptor steps of the insulin action pathway have been reported. At the molecular level, several mutations have been described. The patients reported here are from a Yemeni family with a syndrome of insulin resistance similar to leprechaunism in which the parents are second cousins and five of their eight children are affected. However, the phenotypes seem to be less severe than the classical leprechaunism previously described. All the children are alive (oldest 11 years), there is normal subcutaneous tissue, and a normal growth pattern in some of them. It may be that this is a milder type of leprechaunism with a better prognosis, perhaps caused by a different type of mutation from those previously described. Images PMID:8326490

  14. Impact of Maternal Obesity on Inhaled Corticosteroid Use in Childhood: A Registry Based Analysis of First Born Children and a Sibling Pair Analysis

    PubMed Central

    Lowe, Adrian J.; Ekeus, Cecilia; Bråbäck, Lennart; Rajaleid, Kristiina; Forsberg, Bertil; Hjern, Anders

    2013-01-01

    Background It has been proposed that maternal obesity during pregnancy may increase the risk that the child develops allergic disease and asthma, although the mechanisms underpinning this relationship are currently unclear. We sought to assess if this association may be due to confounding by genetic or environmental risk factors that are common to maternal obesity and childhood asthma, using a sibling pair analysis. Methods The study population comprised a Swedish national cohort of term children born between 1992 and 2008 to native Swedish parents. Maternal body mass index (BMI) was measured at 8–10 weeks gestation. Unconditional logistic regression models were used to determine if maternal obesity was associated with increased risk of inhaled corticosteroid (ICS) in 431,718 first-born children, while adjusting for potential confounders. An age-matched discordant sib-pair analysis was performed, taking into account shared genetic and environmental risk factors. Results Maternal over-weight and obesity were associated with increased risk that the child would require ICS (for BMI≥35 kg/m2, aOR = 1.30, 95%CI = 1.10–1.52 compared with normal weight mothers) in children aged 6–12 years. Similar effects were seen in younger children, but in children aged 13–16 years, maternal obesity (BMI≥30) was related to increased risk of ICS use in girls (aOR = 1.28, 95%CI = 1.07–1.53) but not boys (OR = 1.05, 95%CI = 0.87–1.26). The sib-pair analysis, which included 2,034 sib-pairs older than six years who were discordant for both ICS use and maternal BMI category, failed to find any evidence that increasing maternal weight was related to increased risk of ICS use. Conclusion Maternal obesity is associated with increased risk of childhood ICS use up to approximately 12 years of age, but only in girls after this age. These effects could not be confirmed in a sib pair analysis, suggesting either limited statistical power, or the effects of

  15. Effect of number of rooms and sibs on nutritional status among rural Bengalee preschool children from eastern India.

    PubMed

    Biswas, Sadaruddin; Bose, Kaushik

    2011-12-01

    In developing countries including rural India, undernutrition among preschool children is one of the main barriers of the national development. However, there exists scanty information on the prevalence of underweight and stunting and their socio-demographic predictors among preschool children in India and West Bengal. The aim of the present study was to investigate the prevalence of underweight and stunting and the impact of two socio-demographic indicators, namely number of living rooms (NLR) and number of sibs (NS), on them among 1-5 year old Bengalee rural preschool children of Integrated Child Development Services (ICDS) Centres. This cross sectional study was undertaken at 30 randomly selected ICDS centre of Chapra Block, Nadia District, West Bengal, India. A total of 673 children, aged 1-5 years were studied. The overall (age and sex combined) rates of underweight and stunting were 54.40% and 39.20%, respectively. NLR was significantly associated with the prevalence of underweight (chi2 = 4.34, df = 1, p < 0.05) and stunting (chi2 = 8.98, df = 1, p < 0.01) among girls. Similarly, NS had a significant association with prevalence of underweight (chi2 = 10.29, df = 1, p < 0.001) and stunting (chi2 = 5.42, df = 1, p < 0.05) among girls. Girls with < 2 NLR had significant higher risk of being underweight (OR = 1.64, C.I = 1.30-2.62) or stunted (OR=2.23, C.I = 1.31-3.80) than those with > or = 2 NLR. Moreover, girls with > or = 3 NS had significant higher rate of underweight (OR = 2.03, CI = 1.32-3.146) or stunting (OR = 1.69, C.I = 1.09-2.63) than those with < 3 sibs. Logistic regression analyses also revealed that both NLR as well as NS were strong predictors of underweight (NLR: Wald = 4.30, p < 0.05; NS: Wald = 8.74, p < 0.001) and stunting (NLR: Wald = 10.17, p < 0.001; NS: Wald = 5.38, p < 0.05) among girls. Gender discrimination could be a likely cause for this sex difference in the impact of NRL and NS. Moreover, logistic regression were also undertaken

  16. Limited variation found among Norway spruce half-sib families in physiological response to drought and resistance to embolism.

    PubMed

    Chmura, Daniel J; Guzicka, Marzenna; McCulloh, Katherine A; Żytkowiak, Roma

    2016-02-01

    Projections of future climates suggest that droughts (Ds) may become more frequent and severe in many regions. Genetic variation, especially within populations in traits related to D resistance, is poorly investigated in forest trees, but this knowledge is necessary to better understand how forests will respond to water shortages. In this study, we investigated variability among seven open-pollinated half-sib families of a single population and two population-level progenies of Norway spruce (Picea abies (L.) H. Karst.) in their gas exchange response to imposed D and xylem vulnerability to embolism. During their third growing season, saplings were subjected to three treatments-control (C), D (for 19 weeks) and broken drought (BD, 54 days without watering starting in mid-July, then well-watered). In response to D, all families reduced their stomatal conductance (gs) and light-saturated rates of photosynthesis (Amax) in a similar way. After rewatering, the xylem water potential (Ψ) recovered in the BD treatment, but gs and Amax remained lower than in C. Needle starch concentration was altered in both D treatments compared with C. Xylem of D-exposed trees was more vulnerable to embolism than in C. The minimum attained safety margin remained positive for all families, indicating that no catastrophic hydraulic failure occurred in stem xylem during D. Significant family variation was found for Ψ early in the D (midday Ψ between -1.2 and -1.8 MPa), and for needle damage, but not for sapling mortality. Family variation found at the initial stages of D, and not afterward, suggests that all families responded similarly to greater D intensity, exhibiting the species-specific response. Limited variation at the family level indicates that the response to D and the traits we examined were conservative within the species. This may limit breeding opportunities for increased D resistance in Norway spruce in light of expected climatic changes. PMID:26786539

  17. Estimation of the spontaneous mutation rate per nucleotide site in a Drosophila melanogaster full-sib family.

    PubMed

    Keightley, Peter D; Ness, Rob W; Halligan, Daniel L; Haddrill, Penelope R

    2014-01-01

    We employed deep genome sequencing of two parents and 12 of their offspring to estimate the mutation rate per site per generation in a full-sib family of Drosophila melanogaster recently sampled from a natural population. Sites that were homozygous for the same allele in the parents and heterozygous in one or more offspring were categorized as candidate mutations and subjected to detailed analysis. In 1.23 × 10(9) callable sites from 12 individuals, we confirmed six single nucleotide mutations. We estimated the false negative rate in the experiment by generating synthetic mutations using the empirical distributions of numbers of nonreference bases at heterozygous sites in the offspring. The proportion of synthetic mutations at callable sites that we failed to detect was <1%, implying that the false negative rate was extremely low. Our estimate of the point mutation rate is 2.8 × 10(-9) (95% confidence interval = 1.0 × 10(-9) - 6.1 × 10(-9)) per site per generation, which is at the low end of the range of previous estimates, and suggests an effective population size for the species of ∼1.4 × 10(6). At one site, point mutations were present in two individuals, indicating that there had been a premeiotic mutation cluster, although surprisingly one individual had a G→A transition and the other a G→T transversion, possibly associated with error-prone mismatch repair. We also detected three short deletion mutations and no insertions, giving a deletion mutation rate of 1.2 × 10(-9) (95% confidence interval = 0.7 × 10(-9) - 11 × 10(-9)). PMID:24214343

  18. Estimation of the Spontaneous Mutation Rate per Nucleotide Site in a Drosophila melanogaster Full-Sib Family

    PubMed Central

    Keightley, Peter D.; Ness, Rob W.; Halligan, Daniel L.; Haddrill, Penelope R.

    2014-01-01

    We employed deep genome sequencing of two parents and 12 of their offspring to estimate the mutation rate per site per generation in a full-sib family of Drosophila melanogaster recently sampled from a natural population. Sites that were homozygous for the same allele in the parents and heterozygous in one or more offspring were categorized as candidate mutations and subjected to detailed analysis. In 1.23 × 109 callable sites from 12 individuals, we confirmed six single nucleotide mutations. We estimated the false negative rate in the experiment by generating synthetic mutations using the empirical distributions of numbers of nonreference bases at heterozygous sites in the offspring. The proportion of synthetic mutations at callable sites that we failed to detect was <1%, implying that the false negative rate was extremely low. Our estimate of the point mutation rate is 2.8 × 10−9 (95% confidence interval = 1.0 × 10−9 − 6.1 × 10−9) per site per generation, which is at the low end of the range of previous estimates, and suggests an effective population size for the species of ∼1.4 × 106. At one site, point mutations were present in two individuals, indicating that there had been a premeiotic mutation cluster, although surprisingly one individual had a G→A transition and the other a G→T transversion, possibly associated with error-prone mismatch repair. We also detected three short deletion mutations and no insertions, giving a deletion mutation rate of 1.2 × 10−9 (95% confidence interval = 0.7 × 10−9 − 11 × 10−9). PMID:24214343

  19. Protected Flux Pairing Qubit

    NASA Astrophysics Data System (ADS)

    Bell, Matthew; Zhang, Wenyuan; Ioffe, Lev; Gershenson, Michael

    2014-03-01

    We have studied the coherent flux tunneling in a qubit containing two submicron Josephson junctions shunted by a superinductor (a dissipationless inductor with an impedance much greater than the resistance quantum). The two low energy quantum states of this device, 0 and 1, are represented by even and odd number of fluxes in the loop, respectively. This device is dual to the charge pairing Josephson rhombi qubit. The spectrum of the device, studied by microwave spectroscopy, reflects the interference between coherent quantum phase slips in the two junctions (the Aharonov-Casher effect). The time domain measurements demonstrate the suppression of the qubit's energy relaxation in the protected regime, which illustrates the potential of this flux pairing device as a protected quantum circuit. Templeton Foundation, NSF, and ARO.

  20. Existence of best proximity pairs and equilibrium pairs

    NASA Astrophysics Data System (ADS)

    Kim, Won Kyu; Lee, Kyoung Hee

    2006-04-01

    In this paper, using the fixed point theorem for Kakutani factorizable multifunctions, we shall prove new existence theorems of best proximity pairs and equilibrium pairs for free abstract economies, which include the previous fixed point theorems and equilibrium existence theorems.

  1. Genetic evidence of extra-pair paternity and intraspecific brood parasitism in the monk parakeet

    PubMed Central

    2013-01-01

    Introduction The monk parakeet (Myiopsitta monachus) is a widespread invasive species native to southern South America that has become established in many regions of the world. Monk parakeets breed in a large, fully enclosed structure built from twigs, which consist of one to many individual brooding chambers. The species has been considered to be socially and genetically monogamous. However, genetic relatedness of adults to juveniles in the native area was found to be lower than expected for monogamy. To assess the significance of this discrepancy, we examined individual and population genetic patterns of microsatellite loci at two sites in Córdoba province, Argentina. Results We sampled 154 nestlings and 42 adults in Córdoba, Argentina. Mean value of pairwise relatedness of nestlings within chambers was about 0.40. Contrarily, relatedness of nestlings between chambers was close to zero. We found a considerable degree of variation in nestling pairwise relatedness and parentage within chambers, including chambers with combinations of unrelated, half-sib, and full-sib nestlings. The proportion of sibling relatedness indicated monogamy in 47% and extra pair-paternity in 40% of the chambers. We also found intra-brood parasitism in 3% of the chambers. Conclusions Our results indicate that the monk parakeet is sexually polygamous in its native range in Argentina, which is consistent with the observed mean value of relatedness of adults to juveniles of about 0.4. We also confirm the existence of intra-brood parasitism. High density of monk parakeets may favor occurrence of extra-pair paternity and intra-brood parasitism in the native sites. PMID:24209709

  2. Assessing the feasibility of volumetric-modulated arc therapy using simultaneous integrated boost (SIB-VMAT): An analysis for complex head-neck, high-risk prostate and rectal cancer cases

    SciTech Connect

    Cilla, Savino; Deodato, Francesco; Digesù, Cinzia; Macchia, Gabriella; Picardi, Vincenzo; Ferro, Marica; Sallustio, Giuseppina; De Spirito, Marco; Piermattei, Angelo; Morganti, Alessio G.

    2014-04-01

    Intensity-modulated radiotherapy (IMRT) allowed the simultaneous delivery of different doses to different target volumes within a single fraction, an approach called simultaneous integrated boost (SIB). As consequence, the fraction dose to the boost volume can be increased while keeping low doses to the elective volumes, and the number of fractions and overall treatment time will be reduced, translating into better radiobiological effectiveness. In recent years, volumetric-modulated arc therapy (VMAT) has been shown to provide similar plan quality with respect to fixed-field IMRT but with large reduction in treatment time and monitor units (MUs) number. However, the feasibility of VMAT when used with SIB strategy has few investigations to date. We explored the potential of VMAT in a SIB strategy for complex cancer sites. A total of 15 patients were selected, including 5 head-and-neck, 5 high-risk prostate, and 5 rectal cancer cases. Both a double-arc VMAT and a 7-field IMRT plan were generated for each case using Oncentra MasterPlan treatment planning system for an Elekta Precise linac. Dosimetric indexes for targets and organs at risk (OARs) were compared based on dose-volume histograms. Conformity index, homogeneity index, and dose-contrast index were used for target analyses. The equivalent uniform doses and the normal tissue complication probabilities were calculated for main OARs. MUs number and treatment time were analyzed to score treatment efficiency. Pretreatment dosimetry was performed using 2-dimensional (2D)-array dosimeter. SIB-VMAT plans showed a high level of fluence modulation needed for SIB treatments, high conformal dose distribution, similar target coverage, and a tendency to improve OARs sparing compared with the benchmark SIB-IMRT plans. The median treatment times reduced from 13 to 20 minutes to approximately 5 minutes for all cases with SIB-VMAT, with a MUs reduction up to 22.5%. The 2D-array ion-chambers' measurements reported an agreement

  3. Assessing the feasibility of volumetric-modulated arc therapy using simultaneous integrated boost (SIB-VMAT): An analysis for complex head-neck, high-risk prostate and rectal cancer cases.

    PubMed

    Cilla, Savino; Deodato, Francesco; Digesù, Cinzia; Macchia, Gabriella; Picardi, Vincenzo; Ferro, Marica; Sallustio, Giuseppina; De Spirito, Marco; Piermattei, Angelo; Morganti, Alessio G

    2014-01-01

    Intensity-modulated radiotherapy (IMRT) allowed the simultaneous delivery of different doses to different target volumes within a single fraction, an approach called simultaneous integrated boost (SIB). As consequence, the fraction dose to the boost volume can be increased while keeping low doses to the elective volumes, and the number of fractions and overall treatment time will be reduced, translating into better radiobiological effectiveness. In recent years, volumetric-modulated arc therapy (VMAT) has been shown to provide similar plan quality with respect to fixed-field IMRT but with large reduction in treatment time and monitor units (MUs) number. However, the feasibility of VMAT when used with SIB strategy has few investigations to date. We explored the potential of VMAT in a SIB strategy for complex cancer sites. A total of 15 patients were selected, including 5 head-and-neck, 5 high-risk prostate, and 5 rectal cancer cases. Both a double-arc VMAT and a 7-field IMRT plan were generated for each case using Oncentra MasterPlan treatment planning system for an Elekta Precise linac. Dosimetric indexes for targets and organs at risk (OARs) were compared based on dose-volume histograms. Conformity index, homogeneity index, and dose-contrast index were used for target analyses. The equivalent uniform doses and the normal tissue complication probabilities were calculated for main OARs. MUs number and treatment time were analyzed to score treatment efficiency. Pretreatment dosimetry was performed using 2-dimensional (2D)-array dosimeter. SIB-VMAT plans showed a high level of fluence modulation needed for SIB treatments, high conformal dose distribution, similar target coverage, and a tendency to improve OARs sparing compared with the benchmark SIB-IMRT plans. The median treatment times reduced from 13 to 20 minutes to approximately 5 minutes for all cases with SIB-VMAT, with a MUs reduction up to 22.5%. The 2D-array ion-chambers' measurements reported an agreement

  4. Normal female carrier and affected male half-sibs with t(X;5)(q13;p15). Location of a gene determining male genital development.

    PubMed

    Callen, D F; Sutherland, G R

    1986-07-01

    A unique family in which half-brothers have a maternally derived t(X;5)(q13;p15) and similar genital malformations is described. This family provides evidence for a gene required for male genital development located at Xq13. PMID:3757297

  5. Multiprocessor switch with selective pairing

    SciTech Connect

    Gara, Alan; Gschwind, Michael K; Salapura, Valentina

    2014-03-11

    System, method and computer program product for a multiprocessing system to offer selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). Each paired microprocessor or processor cores that provide one highly reliable thread for high-reliability connect with a system components such as a memory "nest" (or memory hierarchy), an optional system controller, and optional interrupt controller, optional I/O or peripheral devices, etc. The memory nest is attached to a selective pairing facility via a switch or a bus

  6. Multiple origins of asteroid pairs

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.

    2016-01-01

    Rotationally fissioned asteroids produce unbound asteroid pairs that have very similar heliocentric orbits. Backward integration of their current heliocentric orbits provides an age of closest proximity that can be used to date the rotational fission event. Most asteroid pairs follow a predicted theoretical relationship between the primary spin period and the mass ratio of the two pair members that is a direct consequence of the YORP-induced rotational fission hypothesis. If the progenitor asteroid has strength, asteroid pairs may have higher mass ratios or faster rotating primaries. However, the process of secondary fission leaves the originally predicted trend unaltered. We also describe the characteristics of pair members produced by four alternative routes from a rotational fission event to an asteroid pair. Unlike direct formation from the event itself, the age of closest proximity of these pairs cannot generally be used to date the rotational fission event since considerable time may have passed.

  7. Genetic Mapping of Quantitative Trait Loci Controlling Growth and Wood Quality Traits in Eucalyptus Grandis Using a Maternal Half-Sib Family and Rapd Markers

    PubMed Central

    Grattapaglia, D.; Bertolucci, FLG.; Penchel, R.; Sederoff, R. R.

    1996-01-01

    Quantitative trait loci (QTL) mapping of forest productivity traits was performed using an open pollinated half-sib family of Eucalyptus grandis. For volume growth, a sequential QTL mapping approach was applied using bulk segregant analysis (BSA), selective genotyping (SG) and cosegregation analysis (CSA). Despite the low heritability of this trait and the heterogeneous genetic background employed for mapping. BSA detected one putative QTL and SG two out of the three later found by CSA. The three putative QTL for volume growth were found to control 13.7% of the phenotypic variation, corresponding to an estimated 43.7% of the genetic variation. For wood specific gravity five QTL were identified controlling 24.7% of the phenotypic variation corresponding to 49% of the genetic variation. Overlapping QTL for CBH, WSG and percentage dry weight of bark were observed. A significant case of digenic epistasis was found, involving unlinked QTL for volume. Our results demonstrate the applicability of the within half-sib design for QTL mapping in forest trees and indicate the existence of major genes involved in the expression of economically important traits related to forest productivity in Eucalyptus grandis. These findings have important implications for marker-assisted tree breeding. PMID:8913761

  8. Comparison of GCM subgrid fluxes calculated using BATS and SiB schemes with a coupled land-atmosphere high-resolution model

    SciTech Connect

    Shen, Jinmei; Arritt, R.W.

    1996-12-31

    The importance of land-atmosphere interactions and biosphere in climate change studies has long been recognized, and several land-atmosphere interaction schemes have been developed. Among these, the Simple Biosphere scheme (SiB) of Sellers et al. and the Biosphere Atmosphere Transfer Scheme (BATS) of Dickinson et al. are two of the most widely known. The effects of GCM subgrid-scale inhomogeneities of surface properties in general circulation models also has received increasing attention in recent years. However, due to the complexity of land surface processes and the difficulty to prescribe the large number of parameters that determine atmospheric and soil interactions with vegetation, many previous studies and results seem to be contradictory. A GCM grid element typically represents an area of 10{sup 4}-10{sup 6} km{sup 2}. Within such an area, there exist variations of soil type, soil wetness, vegetation type, vegetation density and topography, as well as urban areas and water bodies. In this paper, we incorporate both BATS and SiB2 land surface process schemes into a nonhydrostatic, compressible version of AMBLE model (Atmospheric Model -- Boundary-Layer Emphasis), and compare the surface heat fluxes and mesoscale circulations calculated using the two schemes. 8 refs., 5 figs.

  9. Genetic diversity and morphological characterization of half-sib families of Heliconia bihai L., H. chartacea Lane ex Barreiros, and H. wagneriana Peterson.

    PubMed

    Pereira, F R A; Moraes Filho, R M; Martins, L S S; Montarroyos, A V V; Loges, V

    2016-01-01

    The Neotropical Heliconia genus contains highly diversified plants and up to 220 species have been reported from the north of Mexico to the South of Brazil. Heliconia are cultivated as ornamental garden plants and as cut flowers. All species can be propagated by seeds or vegetatively, through rhizomes. Depending on the species, an individual plant can spread and form large clonal populations. H. bihai L., H. chartacea Lane ex Barreiros, and H. wagneriana Petersen are among the most cultivated Heliconia species. However, they still have undesirable characteristics that could be improved for the international market. This study aimed to characterize 15 half-sib families originating from commercial cultivations, by morphological and molecular markers. The genetic diversity (ĤE), considering all individuals of the three species was 0.103. For H. bihai half-sib families, the value of ĤE was 0.242, showing high genetic diversity. The ĤE value for H. chartacea was 0.068, indicating low genetic diversity. All individuals of H. wagneriana showed the same band patterns, suggesting that the two parental plants were propagated vegetatively from the same plant and may have undergone some endogamic crossings. These results showed that molecular characterization can differentiate individuals closely related as half-siblings for H. bihai and H. chartacea, despite the low variation observed with morphological descriptors. The high genetic diversity observed in H. bihai half-sibling genotypes can provide valuable resources for breeding programs. PMID:27420942

  10. Stereo Pair, Honolulu, Oahu

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Honolulu, on the island of Oahu, is a large and growing urban area. This stereoscopic image pair, combining a Landsat image with topography measured by the Shuttle Radar Topography Mission (SRTM), shows how topography controls the urban pattern. This color image can be viewed in 3-D by viewing the left image with the right eye and the right image with the left eye (cross-eyed viewing), or by downloading and printing the image pair, and viewing them with a stereoscope.

    Features of interest in this scene include Diamond Head (an extinct volcano near the bottom of the image), Waikiki Beach (just above Diamond Head), the Punchbowl National Cemetary (another extinct volcano, near the image center), downtown Honolulu and Honolulu harbor (image left-center), and offshore reef patterns. The slopes of the Koolau mountain range are seen in the right half of the image. Clouds commonly hang above ridges and peaks of the Hawaiian Islands, but in this synthesized stereo rendition appear draped directly on the mountains. The clouds are actually about 1000 meters (3300 feet) above sea level.

    This stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with a Landsat 7 Thematic Mapper image collected at the same time as the SRTM flight. The topography data were used to create two differing perspectives, one for each eye. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. The United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota, provided the Landsat data.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three-dimensional measurements of the

  11. Frustrated Lewis Pairs.

    PubMed

    Stephan, Douglas W

    2015-08-19

    The articulation of the notion of "frustrated Lewis pairs" (FLPs), which emerged from the discovery that H2 can be reversibly activated by combinations of sterically encumbered Lewis acids and bases, has prompted a great deal of recent activity. Perhaps the most remarkable consequence has been the development of FLP catalysts for the hydrogenation of a range of organic substrates. In the past 9 years, the substrate scope has evolved from bulky polar species to include a wide range of unsaturated organic molecules. In addition, effective stereoselective metal-free hydrogenation catalysts have begun to emerge. The mechanism of this activation of H2 has been explored, and the nature and range of Lewis acid/base combinations capable of effecting such activation have also expanded to include a variety of non-metal species. The reactivity of FLPs with a variety of other small molecules, including olefins, alkynes, and a range of element oxides, has also been developed. Although much of this latter chemistry has uncovered unique stoichiometric transformations, metal-free catalytic hydroamination, CO2 reduction chemistry, and applications in polymerization have also been achieved. The concept is also beginning to find applications in bioinorganic and materials chemistry as well as heterogeneous catalysis. This Perspective highlights many of these developments and discusses the relationship between FLPs and established chemistry. Some of the directions and developments that are likely to emerge from FLP chemistry in the future are also presented. PMID:26214241

  12. Pygmy stars: first pair.

    PubMed

    Zwicky, F

    1966-07-01

    The binary LP 101-15/16 having the proper motion of 1.62 seconds of arc per year has been studied with the prime-focus spectrograph of the 200-inch (508 cm) telescope. Indications are that LP 101-15/16 is the first pair of pygmy stars ever discovered. One of its components, LP 101-16, is probably a blue pygmy star which is at least four magnitudes fainter than the ordinary white dwarfs. Also, two of the Balmer lines in absorption appear to be displaced toward the red by amounts which indicate the existence of an Einstein gravitational red shift corresponding to about 1000 km sec-1. On the other hand LP 101-15 is red and shows an entirely new type of spectrum, which suggests that it may be a first representative of a type of red pygmy star which is 2.5 magnitudes fainter than the M-type dwarf stars of the main sequence. PMID:17730606

  13. Controversies in kidney paired donation.

    PubMed

    Gentry, Sommer E; Montgomery, Robert A; Segev, Dorry L

    2012-07-01

    Kidney paired donation represented 10% of living kidney donation in the United States in 2011. National registries around the world and several separate registries in the United States arrange paired donations, although with significant variations in their practices. Concerns about ethical considerations, clinical advisability, and the quantitative effectiveness of these approaches in paired donation result in these variations. For instance, although donor travel can be burdensome and might discourage paired donation, it was nearly universal until convincing analysis showed that living donor kidneys can sustain many hours of cold ischemia time without adverse consequences. Opinions also differ about whether the last donor in a chain of paired donation transplants initiated by a nondirected donor should donate immediately to someone on the deceased donor wait-list (a domino or closed chain) or should be asked to wait some length of time and donate to start another sequence of paired donations later (an open chain); some argue that asking the donor to donate later may be coercive, and others focus on balancing the probability that the waiting donor withdraws versus the number of additional transplants if the chain can be continued. Other controversies in paired donation include simultaneous versus nonsimultaneous donor operations, whether to enroll compatible pairs, and interactions with desensitization protocols. Efforts to expand public awareness of and participation in paired donation are needed to generate more transplant opportunities. PMID:22732046

  14. Lone pairs: an electrostatic viewpoint.

    PubMed

    Kumar, Anmol; Gadre, Shridhar R; Mohan, Neetha; Suresh, Cherumuttathu H

    2014-01-16

    A clear-cut definition of lone pairs has been offered in terms of characteristics of minima in molecular electrostatic potential (MESP). The largest eigenvalue and corresponding eigenvector of the Hessian at the minima are shown to distinguish lone pair regions from the other types of electron localization (such as π bonds). A comparative study of lone pairs as depicted by various other scalar fields such as the Laplacian of electron density and electron localization function is made. Further, an attempt has been made to generalize the definition of lone pairs to the case of cations. PMID:24372481

  15. Methods for Identifying Pair Halos

    NASA Astrophysics Data System (ADS)

    Wells, Brendan; Caputo, Regina; Atwood, William; Ritz, Steven M.

    2016-01-01

    The flux of very high energy gamma rays from active galactic nuclei (AGN) is attenuated via interactions with extragalactic background photons and is converted into e+e- pairs. With non-zero intergalactic magnetic fields, the electrons and positrons will deflect as they propagate and simultaneously lose energy by upscattering cosmic microwave background photons. "Pair halos," the visible consequences of these electromagnetic cascades, are faint and difficult to observe against their AGN counterparts. We investigate three methods for indirectly identifying pair halos, using a two-component approach to model the AGN core/halo image. We estimate each method's sensitivity by utilizing a new, detailed Monte Carlo pair-halo simulation.

  16. Pairs of promoter pairs in a web of transcription.

    PubMed

    Kaplan, Craig D

    2016-08-30

    A new analysis has characterized a fundamental building block of complex transcribed loci. Constellations of core promoters can generally be reduced to pairs of divergent transcription units, where the distance between the pairs of transcription units correlates with constraints on genomic context, which in turn contribute to transcript fate. PMID:27573684

  17. Evolution of displays within the pair bond

    PubMed Central

    Servedio, Maria R.; Price, Trevor D.; Lande, Russell

    2013-01-01

    Although sexual selection is an important cause of display evolution, in socially monogamous species (e.g. many birds), displays continue after formation of the pair bond. Here, we consider that these displays evolve because they stimulate the partner to increase investment in offspring. Our study is motivated by elaborate mutual displays in species that are largely monomorphic and have long-term pair bonds (e.g. the great crested grebe, Podiceps cristatus) and by many empirical results evidencing that display manipulation affects parental investment. Using population genetic models, we show that a necessary condition for the permanent establishment of mutual displays in the pair bond is that the benefit of investment by the pair is more than twice that resulting from investment by a single individual. Pre-existing biases to respond to displays by increased investment are a necessary component of display evolution. We also consider examples where one sex (e.g. males) stimulates increased investment in offspring by the other sex. Here, display and additional investment cannot evolve permanently, but can increase and linger at high frequency for a long time before loss. We discuss how such transient effects may lead to the evolution of permanent displays as a result of evolution at additional loci. PMID:23427172

  18. Assessment Strategies for Pair Programming

    ERIC Educational Resources Information Center

    Hahn, Jan Hendrik; Mentz, Elsa; Meyer, Lukas

    2009-01-01

    Although pair programming has proved its usefulness in teaching and learning programming skills, it is difficult to assess the individual roles and abilities of students whilst programming in pairs. (Note that within this manuscript, the term assessment refers to evaluating individual student performance.) Assessing only the outcomes of a pair…

  19. Supernovae in paired host galaxies

    NASA Astrophysics Data System (ADS)

    Nazaryan, T. A.; Petrosian, A. R.; Hakobyan, A. A.; Adibekyan, V. Zh.; Kunth, D.; Mamon, G. A.; Turatto, M.; Aramyan, L. S.

    2014-12-01

    We investigate the influence of close neighbor galaxies on the properties of supernovae (SNe) and their host galaxies using 56 SNe located in pairs of galaxies with different levels of star formation (SF) and nuclear activity. The mean distance of type II SNe from nuclei of hosts is greater by about a factor of 2 than that of type Ibc SNe. For the first time it is shown that SNe Ibc are located in pairs with significantly smaller difference of radial velocities between components than pairs containing SNe Ia and II. We consider this as a result of higher star formation rate (SFR) of these closer systems of galaxies. SN types are not correlated with the luminosity ratio of host and neighbor galaxies in pairs. The orientation of SNe with respect to the preferred direction toward neighbor galaxy is found to be isotropic and independent of kinematical properties of the galaxy pair.

  20. Property (RD) for Hecke Pairs

    NASA Astrophysics Data System (ADS)

    Shirbisheh, Vahid

    2012-06-01

    As the first step towards developing noncommutative geometry over Hecke C ∗-algebras, we study property (RD) (Rapid Decay) for Hecke pairs. When the subgroup H in a Hecke pair ( G, H) is finite, we show that the Hecke pair ( G, H) has (RD) if and only if G has (RD). This provides us with a family of examples of Hecke pairs with property (RD). We also adapt Paul Jolissant's works in Jolissaint (J K-Theory 2:723-735, 1989; Trans Amer Math Soc 317(1):167-196, 1990) to the setting of Hecke C ∗-algebras and show that when a Hecke pair ( G, H) has property (RD), the algebra of rapidly decreasing functions on the set of double cosets is closed under holomorphic functional calculus of the associated (reduced) Hecke C ∗-algebra. Hence they have the same K 0-groups.

  1. Base pairing and base mis-pairing in nucleic acids

    NASA Technical Reports Server (NTRS)

    Wang, A. H. J.; Rich, A.

    1986-01-01

    In recent years we have learned that DNA is conformationally active. It can exist in a number of different stable conformations including both right-handed and left-handed forms. Using single crystal X-ray diffraction analysis we are able to discover not only additional conformations of the nucleic acids but also different types of hydrogen bonded base-base interactions. Although Watson-Crick base pairings are the predominant type of interaction in double helical DNA, they are not the only types. Recently, we have been able to examine mismatching of guanine-thymine base pairs in left-handed Z-DNA at atomic resolution (1A). A minimum amount of distortion of the sugar phosphate backbone is found in the G x T pairing in which the bases are held together by two hydrogen bonds in the wobble pairing interaction. Because of the high resolution of the analysis we can visualize water molecules which fill in to accommodate the other hydrogen bonding positions in the bases which are not used in the base-base interactions. Studies on other DNA oligomers have revealed that other types of non-Watson-Crick hydrogen bonding interactions can occur. In the structure of a DNA octamer with the sequence d(GCGTACGC) complexed to an antibiotic triostin A, it was found that the two central AT base pairs are held together by Hoogsteen rather than Watson-Crick base pairs. Similarly, the G x C base pairs at the ends are also Hoogsteen rather than Watson-Crick pairing. Hoogsteen base pairs make a modified helix which is distinct from the Watson-Crick double helix.

  2. Genetic variability, character association, and path analysis for economic traits in menthofuran rich half-sib seed progeny of Mentha piperita L.

    PubMed

    Kumar, Birendra; Mali, Himanshi; Gupta, Ekta

    2014-01-01

    Menthofuran rich eight half-sib seed progeny of Mentha piperita (MPS-36) were studied for various genetic parameters, namely, coefficient of variation, heritability, genetic advance, correlation, and path of various plant and oil attributes, namely, plant height, L:S ratio, herb yield, β -myrcene, limonene, 1,8-cineole, menthone, menthofuran, neomenthone, pulegone, and menthol. Maximum genotypic coefficient of variation and genetic advance as percentage of mean were recorded for pulegone, followed by menthofuran and 1,8-cineole. The genotypic correlation in general was higher than phenotypic; positive significant correlation was recorded for limonene with 1,8-cineole and menthone, β -myrcene with limonene, and 1,8-cineole and menthofuran with neomenthol. A high direct positive effect on menthofuran was of neomenthol. PMID:24963471

  3. Genetic Variability, Character Association, and Path Analysis for Economic Traits in Menthofuran Rich Half-Sib Seed Progeny of Mentha piperita L.

    PubMed Central

    Kumar, Birendra; Mali, Himanshi; Gupta, Ekta

    2014-01-01

    Menthofuran rich eight half-sib seed progeny of Mentha piperita (MPS-36) were studied for various genetic parameters, namely, coefficient of variation, heritability, genetic advance, correlation, and path of various plant and oil attributes, namely, plant height, L : S ratio, herb yield, β-myrcene, limonene, 1,8-cineole, menthone, menthofuran, neomenthone, pulegone, and menthol. Maximum genotypic coefficient of variation and genetic advance as percentage of mean were recorded for pulegone, followed by menthofuran and 1,8-cineole. The genotypic correlation in general was higher than phenotypic; positive significant correlation was recorded for limonene with 1,8-cineole and menthone, β-myrcene with limonene, and 1,8-cineole and menthofuran with neomenthol. A high direct positive effect on menthofuran was of neomenthol. PMID:24963471

  4. Increased extra-pair paternity in broods of aging males and enhanced recruitment of extra-pair young in a migratory bird

    PubMed Central

    Bowers, E. Keith; Forsman, Anna M.; Masters, Brian S.; Johnson, Bonnie G. P.; Johnson, L. Scott; Sakaluk, Scott K.; Thompson, Charles F.

    2015-01-01

    Despite keen interest in extra-pair mating in birds, its adaptive significance remains unresolved. Here, we use a multi-year dataset to test whether traits of a female’s social mate influence her propensity to produce extra-pair offspring in a population of house wrens, and whether producing extra-pair young has consequences for a female’s fitness through effects on offspring survival. Females were most likely to produce extra-pair offspring when paired with old males and when paired with males on poor-quality territories, although this latter effect was marginally non-significant. Among offspring, the cutaneous immunity of within-pair young decreased as the age of their sires increased, but cutaneous immunity of extra-pair young was not affected by the age of their extra-pair sires or by the age of the males rearing them. Extra-pair offspring were more likely than within-pair offspring to return as breeding adults to the local population, with extra-pair sons being more likely to return as a breeder for multiple years. Our findings support the hypothesis that females produce extra-pair offspring to enhance their inclusive fitness beyond what they are capable of given the male with which they are socially paired. PMID:26258950

  5. Stereo Pair, Patagonia, Argentina

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This view of northern Patagonia, at Los Menucos, Argentina shows remnants of relatively young volcanoes built upon an eroded plain of much older and contorted volcanic, granitic, and sedimentary rocks. The large purple, brown, and green 'butterfly' pattern is a single volcano that has been deeply eroded. Large holes on the volcano's flanks indicate that they may have collapsed soon after eruption, as fluid molten rock drained out from under its cooled and solidified outer shell. At the upper left, a more recent eruption occurred and produced a small volcanic cone and a long stream of lava, which flowed down a gully. At the top of the image, volcanic intrusions permeated the older rocks resulting in a chain of small dark volcanic peaks. At the top center of the image, two halves of a tan ellipse pattern are offset from each other. This feature is an old igneous intrusion that has been split by a right-lateral fault. The apparent offset is about 6.6 kilometers (4 miles). Color, tonal, and topographic discontinuities reveal the fault trace as it extends across the image to the lower left. However, young unbroken basalt flows show that the fault has not been active recently.

    This cross-eyed stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with an enhanced Landsat 7satellite color image. The topography data are used to create two differing perspectives of a single image, one perspective for each eye. In doing so, each point in the image is shifted slightly, depending on its elevation. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.

    Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive

  6. Stereo Pair: Patagonia, Argentina

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This view of northern Patagonia, near El Cain, Argentina shows complexly eroded volcanic terrain, with basalt mesas, sinkholes, landslide debris, playas, and relatively few integrated drainage channels. Surrounding this site (but also extending far to the east) is a broad plateau capped by basalt, the Meseta de Somuncura. Here, near the western edge of the plateau, erosion has broken through the basalt cap in a variety of ways. On the mesas, water-filled sinkholes (lower left) are most likely the result of the collapse of old lava tubes. Along the edges of the mesas (several locations) the basalt seems to be sliding away from the plateau in a series of slices. Water erosion by overland flow is also evident, particularly in canyons where vegetation blankets the drainage channels (green patterns, bottom of image). However, overland water flow does not extend very far at any location. This entire site drains to local playas, some of which are seen here (blue). While the water can reach the playas and then evaporate, what becomes of the eroded rock debris? Wind might excavate some of the finer eroded debris, but the fate of much of the missing bedrock remains mysterious.

    This cross-eyed stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with an enhanced Landsat 7 satellite color image. The topography data are used to create two differing perspectives of a single image, one perspective for each eye. In doing so, each point in the image is shifted slightly, depending on its elevation. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.

    Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The

  7. QTL Mapping of Growth-Related Traits in a Full-Sib Family of Rubber Tree (Hevea brasiliensis) Evaluated in a Sub-Tropical Climate

    PubMed Central

    Mantello, Camila Campos; Silva, Carla Cristina; Garcia, Dominique; Le Guen, Vincent; Cardoso, Saulo Emilio Almeida; Garcia, Antonio Augusto Franco; Souza, Anete Pereira

    2013-01-01

    The rubber tree (Hevea spp.), cultivated in equatorial and tropical countries, is the primary plant used in natural rubber production. Due to genetic and physiological constraints, inbred lines of this species are not available. Therefore, alternative approaches are required for the characterization of this species, such as the genetic mapping of full-sib crosses derived from outbred parents. In the present study, an integrated genetic map was obtained for a full-sib cross family with simple sequence repeats (SSRs) and expressed sequence tag (EST-SSR) markers, which can display different segregation patterns. To study the genetic architecture of the traits related to growth in two different conditions (winter and summer), quantitative trait loci (QTL) mapping was also performed using the integrated map. Traits evaluated were height and girth growth, and the statistical model was based in an extension of composite interval mapping. The obtained molecular genetic map has 284 markers distributed among 23 linkage groups with a total length of 2688.8 cM. A total of 18 QTLs for growth traits during the summer and winter seasons were detected. A comparison between the different seasons was also conducted. For height, QTLs detected during the summer season were different from the ones detected during winter season. This type of difference was also observed for girth. Integrated maps are important for genetics studies in outbred species because they represent more accurately the polymorphisms observed in the genitors. QTL mapping revealed several interesting findings, such as a dominance effect and unique segregation patterns that each QTL could exhibit, which were independent of the flanking markers. The QTLs identified in this study, especially those related to phenotypic variation associated with winter could help studies of marker-assisted selection that are particularly important when the objective of a breeding program is to obtain phenotypes that are adapted to sub

  8. A revised land surface parameterization (SiB2) for atmospheric GCMs. Part II: The generation of global fields of terrestrial biophysical parameters from satellite data

    SciTech Connect

    Sellers, P.J.; Tucker, C.J.; Collatz, G.J.

    1996-04-01

    The global parameter fields used in the revised Simple Biosphere Model (SiB2) of Sellers et al. are reviewed. The most important innovation over the earlier SiB1 parameter set of Dorman and Sellers is the use of satellite data to specify the time-varying phenological properties of FPAR, leaf area index, and canopy greenness fraction. This was done by processing a monthly 1{degrees} normalized difference vegetation index (NDVI) dataset obtained from Advanced Very High Resolution Radiometer red and near-infrared data. Corrections were applied to the source NDVI dataset to account for (1) obvious anomalies in the data time series, (2) the effect of variations in solar zenith angle, (3) data dropouts in cold regions where a temperature threshold procedure designed to screen for clouds also eliminated cold land surface points, and (4) persistent cloud cover in the Tropics. An outline of the procedures for calculating the land surface parameters form the corrected NDVI dataset is given, and a brief description is provided of sourcematerial, mainly derived form in situ observations, that was used in addition to the NDVI data. The datasets summarized in this paper should be superior to prescriptions currently used in most land surface parameterizations in that the spatial and temporal dynamics of key land surface parameters, in particular those related to vegetation, are obtained directly from a consistent set of global-scale observations instead of being inferred from a variety of survey-based land-cover classification. 55 refs., 24 figs., 6 tabs.

  9. IsoBED: a tool for automatic calculation of biologically equivalent fractionation schedules in radiotherapy using IMRT with a simultaneous integrated boost (SIB) technique

    PubMed Central

    2011-01-01

    Background An advantage of the Intensity Modulated Radiotherapy (IMRT) technique is the feasibility to deliver different therapeutic dose levels to PTVs in a single treatment session using the Simultaneous Integrated Boost (SIB) technique. The paper aims to describe an automated tool to calculate the dose to be delivered with the SIB-IMRT technique in different anatomical regions that have the same Biological Equivalent Dose (BED), i.e. IsoBED, compared to the standard fractionation. Methods Based on the Linear Quadratic Model (LQM), we developed software that allows treatment schedules, biologically equivalent to standard fractionations, to be calculated. The main radiobiological parameters from literature are included in a database inside the software, which can be updated according to the clinical experience of each Institute. In particular, the BED to each target volume will be computed based on the alpha/beta ratio, total dose and the dose per fraction (generally 2 Gy for a standard fractionation). Then, after selecting the reference target, i.e. the PTV that controls the fractionation, a new total dose and dose per fraction providing the same isoBED will be calculated for each target volume. Results The IsoBED Software developed allows: 1) the calculation of new IsoBED treatment schedules derived from standard prescriptions and based on LQM, 2) the conversion of the dose-volume histograms (DVHs) for each Target and OAR to a nominal standard dose at 2Gy per fraction in order to be shown together with the DV-constraints from literature, based on the LQM and radiobiological parameters, and 3) the calculation of Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) curve versus the prescribed dose to the reference target. PMID:21554675

  10. Ion Pair-π Interactions.

    PubMed

    Fujisawa, Kaori; Humbert-Droz, Marie; Letrun, Romain; Vauthey, Eric; Wesolowski, Tomasz A; Sakai, Naomi; Matile, Stefan

    2015-09-01

    We report that anion-π and cation-π interactions can occur on the same aromatic surface. Interactions of this type are referred to as ion pair-π interactions. Their existence, nature, and significance are elaborated in the context of spectral tuning, ion binding in solution, and activation of cell-penetrating peptides. The origin of spectral tuning by ion pair-π interactions is unraveled with energy-minimized excited-state structures: The solvent- and pH-independent red shift of absorption and emission of push-pull fluorophores originates from antiparallel ion pair-π attraction to their polarized excited state. In contrast, the complementary parallel ion pair-π repulsion is spectroscopically irrelevant, in part because of charge neutralization by intriguing proton and electron transfers on excited push-pull surfaces. With time-resolved fluorescence measurements, very important differences between antiparallel and parallel ion pair-π interactions are identified and quantitatively dissected from interference by aggregation and ion pair dissociation. Contributions from hydrogen bonding, proton transfer, π-π interactions, chromophore twisting, ion pairing, and self-assembly are systematically addressed and eliminated by concise structural modifications. Ion-exchange studies in solution, activation of cell-penetrating peptides in vesicles, and computational analysis all imply that the situation in the ground state is complementary to spectral tuning in the excited state; i.e., parallel rather than antiparallel ion pair-π interactions are preferred, despite repulsion from the push-pull dipole. The overall quite complete picture of ion pair-π interactions provided by these remarkably coherent yet complex results is expected to attract attention throughout the multiple disciplines of chemistry involved. PMID:26291550

  11. Pairing Properties of Superheavy Nuclei

    SciTech Connect

    Staszczak, A.; Dobaczewski, J.; Nazarewicz, Witold

    2007-01-01

    Pairing properties of even-even superheavy N=184 isotones are studied within the Skyrme-Hartree-Fock+BCS approach. In the particle-hole channel we take the Skyrme energy density functional SLy4, while in the particle-particle channel we employ the seniority pairing force and zero-range delta-interactions with different forms of density dependence. We conclude that the calculated static fission trajectories weakly depend on the specific form of the delta-pairing interaction. We also investigate the impact of triaxiality on the inner fission barrier and find a rather strong Z dependence of the effect.

  12. Pairing Correlations at High Spins

    NASA Astrophysics Data System (ADS)

    Ma, Hai-Liang; Dong, Bao-Guo; Zhang, Yan; Fan, Ping; Yuan, Da-Qing; Zhu, Shen-Yun; Zhang, Huan-Qiao; Petrache, C. M.; Ragnarsson, I.; Carlsson, B. G.

    The pairing correcting energies at high spins in 161Lu and 138Nd are studied by comparing the results of the cranked-Nilsson-Strutinsky (CNS) and cranked-Nilsson-Strutinsky-Bogoliubov (CNSB) models. It is concluded that the Coriolis effect rather than the rotational alignment effect plays a major role in the reduction of the pairing correlations in the high spin region. Then we proposed an average pairing correction method which not only better reproduces the experimental data comparing with the CNS model but also enables a clean-cut tracing of the configurations thus the full-spin-range discussion on the various rotating bands.

  13. Pairing in hot rotating nuclei

    SciTech Connect

    Hung, N. Quang; Dang, N. Dinh

    2008-12-15

    Nuclear pairing properties are studied within an approach that includes the quasiparticle-number fluctuation (QNF) and coupling to the quasiparticle-pair vibrations at finite temperature and angular momentum. The formalism is developed to describe noncollective rotations about the symmetry axis. The numerical calculations are performed within a doubly folded equidistant multilevel model as well as several realistic nuclei. The results obtained for the pairing gap, total energy, and heat capacity show that the QNF smoothes out the sharp SN phase transition and leads to the appearance of a thermally assisted pairing gap in rotating nuclei at finite temperature. The corrections due to the dynamic coupling to SCQRPA vibrations and particle-number projection are analyzed. The effect of backbending of the momentum of inertia as a function of squared angular velocity is also discussed.

  14. Dynamical interactions of galaxy pairs

    NASA Technical Reports Server (NTRS)

    Athanassoula, E.

    1990-01-01

    Here the author briefly reviews the dynamics of sinking satellites and the effect of companions on elliptical galaxies. The author then discusses recent work on interacting disk systems, and finally focuses on a favorite interacting pair, NGC 5194/5195.

  15. Behavioral Profiles of Affected and Unaffected Siblings of Children with Autism: Contribution of Measures of Mother-Infant Interaction and Nonverbal Communication

    ERIC Educational Resources Information Center

    Rozga, Agata; Hutman, Ted; Young, Gregory S.; Rogers, Sally J.; Ozonoff, Sally; Dapretto, Mirella; Sigman, Marian

    2011-01-01

    We investigated whether deficits in social gaze and affect and in joint attention behaviors are evident within the first year of life among siblings of children with autism who go on to be diagnosed with autism or ASD (ASD) and siblings who are non-diagnosed (NoASD-sib) compared to low-risk controls. The ASD group did not differ from the other two…

  16. Pair extended coupled cluster doubles

    SciTech Connect

    Henderson, Thomas M.; Scuseria, Gustavo E.; Bulik, Ireneusz W.

    2015-06-07

    The accurate and efficient description of strongly correlated systems remains an important challenge for computational methods. Doubly occupied configuration interaction (DOCI), in which all electrons are paired and no correlations which break these pairs are permitted, can in many cases provide an accurate account of strong correlations, albeit at combinatorial computational cost. Recently, there has been significant interest in a method we refer to as pair coupled cluster doubles (pCCD), a variant of coupled cluster doubles in which the electrons are paired. This is simply because pCCD provides energies nearly identical to those of DOCI, but at mean-field computational cost (disregarding the cost of the two-electron integral transformation). Here, we introduce the more complete pair extended coupled cluster doubles (pECCD) approach which, like pCCD, has mean-field cost and reproduces DOCI energetically. We show that unlike pCCD, pECCD also reproduces the DOCI wave function with high accuracy. Moreover, pECCD yields sensible albeit inexact results even for attractive interactions where pCCD breaks down.

  17. Mass of Galaxies in Pairs

    NASA Astrophysics Data System (ADS)

    Junqueira, S.; Chan, R.

    We have compared the frequency distribution of the dynamical observed quantity log (V r), for a sample of 46 pairs of elliptical galaxies, to the distribution of this quantity obtained from numerical simulations of pairs of galaxies. From such an analysis, where we have considered the structure of the galaxies and its influence in the orbital evolution of the system, we have obtained the characteristic mass and the mass-luminosity ratio for the sample. Our results show that the hypothesis of point-mass in elliptical orbits is, for this sample, an approximation as good as the model that takes into account the structure of the galaxies. The statistical method used here gives an estimate of a more reliable mass, it minimizes the contamination of spurious pairs and it considers adequately the contribution of the physical pairs. We have obtained a characteristic mass to the 46 elliptical pairs of 1.68 × 10^12 +/- 7.01 × 10^11 M_solar with M/L = 17.6 +/- 7.3 (H_0 = 60 km s^-1 Mpc^-1).

  18. Stereo pairs from linear morphing

    NASA Astrophysics Data System (ADS)

    McAllister, David F.

    1998-04-01

    Several authors have recently investigated the ability to compute intermediate views of a scene using given 2D images from arbitrary camera positions. The methods fall under the topic of image based rendering. In the case we give here, linear morphing between two parallel views of a scene produces intermediate views that would have been produced by parallel movement of a camera. Hence, the technique produces images computed in a way that is consistent with the standard off-axis perspective projection method for computing stereo pairs. Using available commercial 2D morphing software, linear morphing can be used to produce stereo pairs from a single image with bilateral symmetry such as a human face. In our case, the second image is produced by horizontal reflection. We describe morphing and show how it can be used to provide stereo pairs from single images.

  19. Pair-Starved Pulsar Magnetospheres

    NASA Technical Reports Server (NTRS)

    Muslimov, Alex G.; Harding, Alice K.

    2009-01-01

    We propose a simple analytic model for the innermost (within the light cylinder of canonical radius, approx. c/Omega) structure of open-magnetic-field lines of a rotating neutron star (NS) with relativistic outflow of charged particles (electrons/positrons) and arbitrary angle between the NS spin and magnetic axes. We present the self-consistent solution of Maxwell's equations for the magnetic field and electric current in the pair-starved regime where the density of electron-positron plasma generated above the pulsar polar cap is not sufficient to completely screen the accelerating electric field and thus establish thee E . B = 0 condition above the pair-formation front up to the very high altitudes within the light cylinder. The proposed mode1 may provide a theoretical framework for developing the refined model of the global pair-starved pulsar magnetosphere.

  20. The coevolution of long-term pair bonds and cooperation.

    PubMed

    Song, Z; Feldman, M W

    2013-05-01

    The evolution of social traits may not only depend on but also change the social structure of the population. In particular, the evolution of pairwise cooperation, such as biparental care, depends on the pair-matching distribution of the population, and the latter often emerges as a collective outcome of individual pair-bonding traits, which are also under selection. Here, we develop an analytical model and individual-based simulations to study the coevolution of long-term pair bonds and cooperation in parental care, where partners play a Snowdrift game in each breeding season. We illustrate that long-term pair bonds may coevolve with cooperation when bonding cost is below a threshold. As long-term pair bonds lead to assortative interactions through pair-matching dynamics, they may promote the prevalence of cooperation. In addition to the pay-off matrix of a single game, the evolutionarily stable equilibrium also depends on bonding cost and accidental divorce rate, and it is determined by a form of balancing selection because the benefit from pair-bond maintenance diminishes as the frequency of cooperators increases. Our findings highlight the importance of ecological factors affecting social bonding cost and stability in understanding the coevolution of social behaviour and social structures, which may lead to the diversity of biological social systems. PMID:23496797

  1. C. Y. Chao, Pair Creation and Pair Annihilation

    NASA Astrophysics Data System (ADS)

    Li, Bing An; Yang, C. N.

    C. Y. Chao's contribution to physicists' acceptance of QED in 1933-1934 through his experiments of 1930 is analyzed. It is pointed out that Blackett and Occhialini's key suggestion of 1933 about hole theory was based on identifying Chao's "additional scattered rays" (1930) as due to pair annihilation.

  2. C. Y. Chao, Pair Creation and Pair Annihilation

    NASA Astrophysics Data System (ADS)

    Li, Bing An; Yang, C. N.

    2013-05-01

    C. Y. Chao's contribution to physicists' acceptance of QED in 1933-1934 through his experiments of 1930 is analyzed. It is pointed out that Blackett and Occhialini's key suggestion of 1933 about hole theory was based on identifying Chao's "additional scattered rays" (1930) as due to pair annihilation.

  3. Invisibly Sanitizable Signature without Pairings

    NASA Astrophysics Data System (ADS)

    Yum, Dae Hyun; Lee, Pil Joong

    Sanitizable signatures allow sanitizers to delete some pre-determined parts of a signed document without invalidating the signature. While ordinary sanitizable signatures allow verifiers to know how many subdocuments have been sanitized, invisibly sanitizable signatures do not leave any clue to the sanitized subdocuments; verifiers do not know whether or not sanitizing has been performed. Previous invisibly sanitizable signature scheme was constructed based on aggregate signature with pairings. In this article, we present the first invisibly sanitizable signature without using pairings. Our proposed scheme is secure under the RSA assumption.

  4. Nucleon pairing in Sn isotopes

    NASA Astrophysics Data System (ADS)

    Imasheva, L.; Ishkhanov, B.; Stepanov, M.; Tretyakova, T.

    2016-01-01

    The systematics of excited states in Sn isotopes are discussed on basis of pairing interaction in nuclei. Nucleon paring leads to formation of excited states multiplets. The estimation of multiplet splitting based on experimental nuclear masses allows one to calculate the position of excited states with different seniority in δ-approximation. The wide systematics of the spectra of Sn isotopes gives a possibility to check the pairing interaction for different subshells and consider the multiplets of excited states in the neutron-rich isotopes far from stability.

  5. Orbiting pairs of walking droplets

    NASA Astrophysics Data System (ADS)

    Siefert, Emmanuel; Bush, John W. M.; Oza, Anand

    2015-11-01

    Droplets may self-propel on the surface of a vibrating fluid bath, pushed forward by their own Faraday pilot-wave field. We present the results of a combined experimental and theoretical investigation of the interaction of pairs of such droplets. Particular attention is given to characterizing the system's dependence on the vibrational forcing of the bath and the impact parameter of the walking droplets. Observed criteria for the capture and stability of orbital pairs are rationalized by accompanying theoretical developments. Thanks to the NSF.

  6. The consequences of pairing questions: context effects in personality measurement.

    PubMed

    Steinberg, L

    2001-08-01

    The effect of context on responses to questions has been a prominent focus in social and political survey research. However, little investigation of context effects has been done for the measurement of psychological constructs. A measure of anger experience and expression in development uses vignettes describing interpersonal situations that provoke varying degrees of anger and require respondents to indicate their affective and/or expressive response to the situation. In this study, the consequences of pairing the two questions for each vignette are investigated. Pairing the anger-experience and likelihood-of-expression questions changes the item's context. Item response theory analysis similar to that used to detect differential item functioning was performed. For some of the items, responding to a single or paired question affected the extremity of responses. The findings are discussed in terms of their implications for personality measurement. PMID:11519936

  7. Re Effects on Phase Stability and Mechanical Properties of MoSS+Mo3Si+Mo5SiB2 alloys

    SciTech Connect

    Yang, Ying; Bei, Hongbin; George, Easo P; Tiley, Jaimie

    2013-01-01

    Because of their high melting points and good oxidation resistance Mo-Si-B alloys are of interest as potential ultrahigh-temperature structural materials. But their major drawbacks are poor ductility and fracture toughness at room temperature. Since alloying with Re has been suggested as a possible solution, we investigate here the effects of Re additions on the microstructure and mechanical properties of a ternary alloy with the composition Mo-12.5Si-8.5B (at.%). This alloy has a three-phase microstructure consisting of Mo solid-solution (MoSS), Mo3Si, and Mo5SiB2 and our results show that up to 8.4 at.% Re can be added to it without changing its microstructure or forming any brittle phase at 1600 C. Three-point bend tests using chevron-notched specimens showed that Re did not improve fracture toughness of the three-phase alloy. Nanoindentation performed on the MoSS phase in the three-phase alloy showed that Re increases Young s modulus, but does not lower hardness as in some Mo solid solution alloys. Based on our thermodynamic calculations and microstructural analyses, the lack of a Re softening effect is attributed to the increased Si levels in the Re-containing MoSS phase since Si is known to increase its hardness. This lack of softening is possibly why there is no Re-induced improvement in fracture toughness.

  8. PREFACE: International Scientific and Research Conference on Topical Issues in Aeronautics and Astronautics (dedicated to the 55th anniversary from the foundation of SibSAU)

    NASA Astrophysics Data System (ADS)

    2015-10-01

    The International Scientific and Research Conference ''Topical Issues in Aeronautics and Astronautics'' is one of the most significant scientific conferences arranged by the Reshetnev Siberian State Aerospace University (SibSAU) which is located in the Krasnoyarsk Region of Russian Federation. In April 2015 this Conference was dedicated to the 55th anniversary from the foundation of the University. Traditionally, the Conference is seen as emblematic of the University's specialty and is annually organized in April, when the first human travelled into space. This Conference is arranged for undergraduate, graduate and postgraduate students, scientists and lecturers, as well as developers, designers and constructors representing leading companies and enterprises of the aerospace sector to give opportunities to present their projects, research work and results. The Conference is a great chance to connect scientists and highly-qualified and skilled specialists with a new community of future scientists and practitioners in the aerospace sector. The Conference proceedings include papers presented by creative young specialists closely connected with aviation and space vehicles - design, production, problem-solving in space machine building and aerospace education, macro- and microeconomic development of the field, new approaches to solving philosophical and social problems, - experienced scientists and specialists, and all those who want to dedicate themselves to aeronautics and astronautics. The selected papers are presented in these proceedings to share University research results, innovations and cutting-edge technologies with the international community to develop aeronautics and astronautics on a global scale.

  9. The effect of drought stress on the leaf relative water content and tuber yield of a half-sib family of 'Katahdin'-derived potato cultivars.

    PubMed

    Soltys-Kalina, Dorota; Plich, Jarosław; Strzelczyk-Żyta, Danuta; Śliwka, Jadwiga; Marczewski, Waldemar

    2016-03-01

    Drought tolerance in plants is a complex trait involving morphological, physiological, and biochemical mechanisms. Hundreds of genes underlie the response of plants to the stress. For crops, selecting cultivars that can produce economically significant yields under drought is a priority. Potato (Solanum tuberosum L.) is considered as drought sensitive crop, although cultivar-dependent differences in tolerance have been described. Cultivar 'Katahdin' possesses many appropriate characteristics and is widely used for breeding purposes worldwide; it also has enhanced tolerance to drought stress. In this study, we evaluated cv. 'Katahdin' and a half-sib family of 17 Katahdin-derived cultivars for leaf relative water content (RWC) and tuber yield under drought stress. The yields of cultivars 'Wauseon', 'Katahdin', 'Magura', 'Calrose', and 'Cayuga' did not significantly decline under drought stress. Among these five, Wauseon exhibited the lowest reduction in both tuber yield and relative water content under water shortage. The data showed that 'Wauseon' is the most attractive cultivar for studies of molecular and physiological processes under drought and for potato breeding due to low yield losses that correspond with high RWC values. This cultivar can serve as a reservoir of potentially useful genes to develop cultivars with enhanced tolerance to this abiotic stress. PMID:27162504

  10. Applying Two Binned Methods to the Simple Biosphere Model (SiB) for Improving the Representation of Spatially Varying Precipitation and Soil Wetness

    NASA Astrophysics Data System (ADS)

    Medina, I. D.; Denning, A.

    2011-12-01

    Representing subgrid-scale variability is a continuing challenge for modelers, but is crucial for accurately calculating the exchanges of energy, moisture, and momentum between the land surface and atmospheric boundary layer. Soil wetness is highly spatially variable and difficult to resolve at grid length scales (~100 km) used in General Circulation Models (GCMs). Currently, GCMs use an area average precipitation rate that results in a single soil wetness value for the entire grid area, and due to the highly nonlinear relationship between soil wetness and evapotranspiration, significant inaccuracies arise in the calculation of the grid area latent heat flux. Using a finer GCM resolution will not solve this problem completely, and other methods of modeling need to be considered. For this study, the binned and alternative binned method of Sellers et al. (2007) are applied to the Simple Biosphere Model (SiB) for improving the representation of spatially varying precipitation, soil wetness and surface-atmosphere fluxes. The methods are tested in a dry, semi-arid, and wet biome for two off-line precipitation distribution experiments, and results are compared to an explicit method, which is ideal for resolving subgrid-scale variability, and the bulk method (area averaged), which is currently in use with GCMs. Results indicate that the alternative binned method better captures the spatial variability in soil wetness and grid area flux calculations produced by the explicit method, and deals realistically with spatially varying precipitation at little additional computational cost to the bulk method.

  11. What Controls the Net Forest-Atmosphere Exchange of Carbonyl Sulfide? Results from 2 Years of Eddy Flux Measurements and SiB Model Simulations

    NASA Astrophysics Data System (ADS)

    Wehr, R. A.; Commane, R.; Baker, I. T.; Munger, J. W.; Saleska, S. R.; Wofsy, S. C.

    2015-12-01

    Carbonyl sulfide (OCS) is currently a focus of ground-, aircraft-, and satellite-based measurements as well as of model development, owing mainly to its potential use as a large-scale proxy for gross primary production (GPP). OCS is taken up by leaves and either taken up or emitted by soils, depending on the circumstances. Because OCS is destroyed by the enzyme carbonic anhydrase within the leaf rather than by any light-dependent reaction, the leaf uptake is expected to be related to the conductance of the diffusive pathway into the leaf (stomata + mesophyll + leaf boundary air layer) rather than to GPP directly, though GPP and the diffusive conductance are often strongly correlated. Here we use 2 years of eddy covariance measurements of the net ecosystem-atmosphere exchange of OCS, along with measurements of the vertical profile of OCS within the forest, to investigate the controls on ecosystem-scale OCS uptake and emission. We compare the OCS measurements, and simultaneous CO2 isotope flux and profile measurements, to predictions from the Simple Biosphere (SiB) model, which has been used to simulate OCS and 13CO2 fluxes for both vegetation and soils but has not yet been systematically tested against these relatively novel tracers. We thereby address the key question: How can measurements of the net ecosystem-atmosphere OCS exchange contribute to empirical quantification of stomatal conductance and GPP and to improving process-based ecosystem models?

  12. Determination of epigenetic inheritance, genetic inheritance, and estimation of genome DNA methylation in a full-sib family of Cupressus sempervirens L.

    PubMed

    Avramidou, Evangelia V; Doulis, Andreas G; Aravanopoulos, Filippos A

    2015-05-15

    Genetic inheritance and epigenetic inheritance are significant determinants of plant evolution, adaptation and plasticity. We studied inheritance of restriction site polymorphisms by the f-AFLP method and epigenetic DNA cytosine methylation inheritance by the f-MSAP technique. The study involved parents and 190 progeny of a Cupressus sempervirens L. full-sib family. Results from AFLP genetic data revealed that 71.8% of the fragments studied are under Mendelian genetic control, whereas faithful Mendelian inheritance for the MSAP fragments was low (4.29%). Further, MSAP fragment analysis showed that total methylation presented a mean of 28.2%, which was higher than the midparent value, while maternal inheritance was higher (5.65%) than paternal (3.01%). Interestingly de novo methylation in the progeny was high (19.65%) compared to parental methylation. Genetic and epigenetic distances for parents and offspring were not correlated (R(2)=0.0005). Furthermore, we studied correlation of total relative methylation and CG methylation with growth (height, diameter). We found CG/CNG methylation (N: A, C, T) to be positively correlated with height and diameter, while total relative methylation and CG methylation were positively correlated with height. Results are discussed in light of further research needed and of their potential application in breeding. PMID:25726917

  13. The effect of drought stress on the leaf relative water content and tuber yield of a half-sib family of ‘Katahdin’-derived potato cultivars

    PubMed Central

    Soltys-Kalina, Dorota; Plich, Jarosław; Strzelczyk-Żyta, Danuta; Śliwka, Jadwiga; Marczewski, Waldemar

    2016-01-01

    Drought tolerance in plants is a complex trait involving morphological, physiological, and biochemical mechanisms. Hundreds of genes underlie the response of plants to the stress. For crops, selecting cultivars that can produce economically significant yields under drought is a priority. Potato (Solanum tuberosum L.) is considered as drought sensitive crop, although cultivar-dependent differences in tolerance have been described. Cultivar ‘Katahdin’ possesses many appropriate characteristics and is widely used for breeding purposes worldwide; it also has enhanced tolerance to drought stress. In this study, we evaluated cv. ‘Katahdin’ and a half-sib family of 17 Katahdin-derived cultivars for leaf relative water content (RWC) and tuber yield under drought stress. The yields of cultivars ‘Wauseon’, ‘Katahdin’, ‘Magura’, ‘Calrose’, and ‘Cayuga’ did not significantly decline under drought stress. Among these five, Wauseon exhibited the lowest reduction in both tuber yield and relative water content under water shortage. The data showed that ‘Wauseon’ is the most attractive cultivar for studies of molecular and physiological processes under drought and for potato breeding due to low yield losses that correspond with high RWC values. This cultivar can serve as a reservoir of potentially useful genes to develop cultivars with enhanced tolerance to this abiotic stress. PMID:27162504

  14. Missing energies at pair creation

    NASA Technical Reports Server (NTRS)

    El-Ela, A. A.; Bagge, E. R.; Hassan, S.

    1985-01-01

    Wilson cloud chamber measurements of the separated spectra of positrons and electrons produced by gamma quanta of 6.14 MeV differ considerably from the theoretically predicted spectra by BETHE and HEITLER, but are in good agreement with those of a modified theory of pair creation.

  15. Pairing Linguistic and Music Intelligences

    ERIC Educational Resources Information Center

    DiEdwardo, MaryAnn Pasda

    2005-01-01

    This article describes how music in the language classroom setting can be a catalyst for developing reading, writing, and understanding skills. Studies suggest that pairing music and linguistic intelligences in the college classroom improves students' grades and abilities to compose theses statements for research papers in courses that emphasize…

  16. Pick a Pair. Being Bony

    ERIC Educational Resources Information Center

    Miller, Pat

    2004-01-01

    This column suggests pairings of fiction and nonfiction books to meet curricular needs and help students to compare/contrast the texts as they may be asked on state tests. The author of this paper focuses on activities surrounding Halloween. Since many schools are discouraged from teaching about Halloween, this can be a great time to investigate…

  17. Paired Reading: Psycholinguistics in Practice.

    ERIC Educational Resources Information Center

    Barrett, James Martin

    1987-01-01

    Contends that children need to learn phonic skills, not necessarily through early direct teaching, but through reading experience. Suggests using Paired Reading, which is validated by psycholinguistic reading theory and provides opportunities to learn to read from context and use innate syntactic and semantic knowledge. (SKC)

  18. Three Rare Diseases in One Sib Pair: RAI1, PCK1, GRIN2B Mutations Associated with Smith-Magenis Syndrome, Cytosolic PEPCK Deficiency and NMDA Receptor Glutamate Insensitivity

    PubMed Central

    Adams, David R; Yuan, Hongjie; Holyoak, Todd; Arajs, Katrina H.; Hakimi, Parvin; Markello, Thomas C; Wolfe, Lynne A; Vilboux, Thierry; Burton, Barbara K; Fajardo, Karin Fuentes; Grahame, George; Holloman, Conisha; Sincan, Murat; Smith, Ann C M; Wells, Gordon A; Huang, Yan; Vega, Hugo; Snyder, James P; Golas, Gretchen A; Tifft, Cynthia J; Boerkoel, Cornelius F; Hanson, Richard W; Traynelis, Stephen F; Kerr, Douglas S; Gahl, William A

    2014-01-01

    The National Institutes of Health Undiagnosed Diseases Program evaluates patients for whom no diagnosis has been discovered despite a comprehensive diagnostic workup. Failure to diagnose a condition may arise from the mutation of genes previously unassociated with disease. However, we hypothesized that this could also co-occur with multiple genetic disorders. As demonstration of a complex syndrome caused by multiple disorders, we report two siblings manifesting both similar and disparate signs and symptoms. They shared a history of episodes of hypoglycemia and lactic acidosis, but had differing exam findings and developmental courses. Clinical acumen and exome sequencing combined with biochemical and functional studies identified three genetic conditions. One sibling had Smith-Magenis Syndrome and a nonsense mutation in the RAI1 gene. The second sibling had a de novo mutation in GRIN2B, which resulted in markedly reduced glutamate potency of the encoded receptor. Both siblings had a protein-destabilizing homozygous mutation in PCK1, which encodes the cytosolic isoform of phosphoenolpyruvate carboxykinase (PEPCK-C). In summary, we present the first clinically-characterized mutation of PCK1 and demonstrate that complex medical disorders can represent the co-occurrence of multiple diseases. PMID:24863970

  19. J=0,J=J{sub max}, and quadrupole pairing

    SciTech Connect

    Hertz-Kintish, Daniel; Zamick, Larry

    2014-12-15

    We consider 2 neutrons and 2 protons in the g{sub 9/2} shell. Wave functions and energy levels are obtained for various interactions. The wavefunctions for states with total angular momentum I greater than or equal to 10 are not affected by what the pairing interaction (J=0T=1) is. Other parts of the interaction are therefore of increased importance. Furthermore, states with I greater than or equal to 12 are not affected by the J=2 interaction.

  20. Clinical outcome in patients treated with simultaneous integrated boost - intensity modulated radiation therapy (SIB-IMRT) with and without concurrent chemotherapy for squamous cell carcinoma of the anal canal.

    PubMed

    Tomasoa, Nathalie B; Meulendijks, Didier; Nijkamp, Jasper; Cats, Annemieke; Dewit, Luc

    2016-06-01

    Background and purpose To retrospectively evaluate locoregional control (LRC), survival and toxicity in anal cancer patients treated with simultaneous integrated boost - intensity modulated radiation therapy (SIB-IMRT) ± concurrent chemotherapy. Methods and materials Patients with squamous cell anal carcinoma stage T1(≥1 cm)-4, N0-3, M0-1 were included. All patients were treated with SIB-IMRT to a total dose of 59.4 Gy delivered to the primary tumor and macroscopically involved lymph nodes and 49.5 Gy to elective lymph node areas. If macroscopic residual tumor was still present in the fifth week of irradiation, a sequential boost of 5.4 Gy was given. Concurrent chemotherapy was administered in locally advanced cases. Acute and late toxicity were scored. Results One hundred and six patients treated consecutively between April 2006 and December 2012 were included. Eighty-seven (82.1%) patients received concurrent chemotherapy. The median follow-up was 47 months (range 2-104 months). Ninety-eight patients reached a clinical complete response (92.5%). Four-year actuarial LRC rate, overall survival and colostomy-free survival were 79%, 77% and 77%, respectively. Acute grade ≥3 toxicity occurred in 67.9% of the patients. Late grade 3 toxicity was seen in 16 patients (15.1%). Conclusions SIB-IMRT ± concurrent chemotherapy for anal cancer was effective with acceptable toxicity. PMID:26878244

  1. Behavioral profiles of affected and unaffected siblings of children with autism: contribution of measures of mother-infant interaction and nonverbal communication.

    PubMed

    Rozga, Agata; Hutman, Ted; Young, Gregory S; Rogers, Sally J; Ozonoff, Sally; Dapretto, Mirella; Sigman, Marian

    2011-03-01

    We investigated whether deficits in social gaze and affect and in joint attention behaviors are evident within the first year of life among siblings of children with autism who go on to be diagnosed with autism or ASD (ASD) and siblings who are non-diagnosed (NoASD-sib) compared to low-risk controls. The ASD group did not differ from the other two groups at 6 months of age in the frequency of gaze, smiles, and vocalizations directed toward the caregiver, nor in their sensitivity to her withdrawal from interaction. However, by 12 months, infants in the ASD group exhibited lower rates of joint attention and requesting behaviors. In contrast, NoASD-sibs did not differ from comparison infants on any variables of interest at 6 and 12 months. PMID:20568002

  2. Extra-Pair Mating and Evolution of Cooperative Neighbourhoods

    PubMed Central

    Eliassen, Sigrunn; Jørgensen, Christian

    2014-01-01

    A striking but unexplained pattern in biology is the promiscuous mating behaviour in socially monogamous species. Although females commonly solicit extra-pair copulations, the adaptive reason has remained elusive. We use evolutionary modelling of breeding ecology to show that females benefit because extra-pair paternity incentivizes males to shift focus from a single brood towards the entire neighbourhood, as they are likely to have offspring there. Male-male cooperation towards public goods and dear enemy effects of reduced territorial aggression evolve from selfish interests, and lead to safer and more productive neighbourhoods. The mechanism provides adaptive explanations for the common empirical observations that females engage in extra-pair copulations, that neighbours dominate as extra-pair sires, and that extra-pair mating correlates with predation mortality and breeding density. The models predict cooperative behaviours at breeding sites where males cooperate more towards public goods than females. Where maternity certainty makes females care for offspring at home, paternity uncertainty and a potential for offspring in several broods make males invest in communal benefits and public goods. The models further predict that benefits of extra-pair mating affect whole nests or neighbourhoods, and that cuckolding males are often cuckolded themselves. Derived from ecological mechanisms, these new perspectives point towards the evolution of sociality in birds, with relevance also for mammals and primates including humans. PMID:24987839

  3. Asymmetric Ion-Pairing Catalysis

    PubMed Central

    Brak, Katrien

    2014-01-01

    Charged intermediates and reagents are ubiquitous in organic transformations. The interaction of these ionic species with chiral neutral, anionic, or cationic small molecules has emerged as a powerful strategy for catalytic, enantioselective synthesis. This review describes developments in the burgeoning field of asymmetric ion-pairing catalysis with an emphasis on the insights that have been gleaned into the structural and mechanistic features that contribute to high asymmetric induction. PMID:23192886

  4. Novel physiological RECQL4 alternative transcript disclosed by molecular characterisation of Rothmund-Thomson Syndrome sibs with mild phenotype.

    PubMed

    Colombo, Elisa Adele; Fontana, Laura; Roversi, Gaia; Negri, Gloria; Castiglia, Daniele; Paradisi, Mauro; Zambruno, Giovanna; Larizza, Lidia

    2014-11-01

    Rothmund-Thomson syndrome is a rare genodermatosis caused by biallelic mutations of the RECQL4 gene and is characterised by poikiloderma, sparse hair, eyelashes and/or eyebrows, small stature, skeletal and dental abnormalities and cancer predisposition. Mutations predicted to result in the loss of RECQL4 protein have been associated with osteosarcoma risk, but mutation(s)-phenotype correlations are better addressed by combined DNA and RNA analyses. We describe two siblings with a mild phenotype, mainly restricted to the skin, who carry the unreported paternal c.2272C>T alteration in exon 14 and the previously reported maternal exon 15 c.2492_2493delAT, both predicted to result in premature termination codons (p.(Arg758*), p.(His831Argfs*52)). However real-time and transcript analysis showed, in the carrier father and affected daughter, increased levels of a novel RECQL4 physiological alternative transcript with partial in-frame skipping of exon 14, generated by increased usage of a weak cryptic splice site. This alternative transcript is expressed in all controls and tested tissues, its upregulation is specific to the paternal c.2272C>T mutation and depends on the abrogation of the binding motifs for SF2 and SRp55 serine/arginine-rich proteins with bypass of the mutation site located in the skipped exon 14 portion. Moreover, in the proband the increased levels of the alternative transcript, likely encoding a protein isoform with residual activity, may compensate for the dearth of the canonical transcript with the c.2492_2493delAT, accounting for the mild clinical phenotype of the siblings. Our results emphasise the value of RNA analysis to better predict the effects of RECQL4 mutations on the clinical phenotype. PMID:24518840

  5. Pair-Instability Supernovae of Non-Zero Metallicity Stars

    NASA Astrophysics Data System (ADS)

    Chen, K.-J.; Heger, A.; Woosley, S.; Almgren, A.; Whalen, D. J.

    2015-10-01

    Observational evidence suggests that some very massive stars in the local Universe may die as pair-instability supernovae. We present 2D simulations of the pair-instability supernova of a non-zero metallicity star. We find that very little mixing occurs in this explosion because metals in the stellar envelope drive strong winds that strip the hydrogen envelope from the star prior to death. Consequently, a reverse shock cannot form and trigger fluid instabilities during the supernova. Only weak mixing driven by nuclear burning occurs in the earliest stages of the supernova, and it is too weak to affect the observational signatures of the explosion.

  6. Pair interactions in red-faced warblers

    USGS Publications Warehouse

    Barber, P.M.; Martin, T.E.; Smith, Kimberly G.

    1998-01-01

    Forty pairs of breeding Red-faced Warblers (Cardellina rubrifrons) were observed in 1992 and 1993 on the Mogollon Rim, Arizona. Intrusions by extra-pair males, interactions between pair members, and other pair interaction behaviors were recorded. The majority of intrusions occurred during the building stage of the nesting cycle. Males responded to intrusions during nest building by decreasing intra-pair distance. Males maintained shorter intra-pair distances by following the female when she initiated movements and by not initiating pair movements themselves. Intra-pair distances were as short or shorter during the incubation period as during nest building, and were shorter during incubation than during egg laying. Males continued to follow females beyond the expected fertile period. Possible explanations for continued mate following include: males guard their mates against predators, males guard their paternity for future nesting attempts, and males respond to extra-pair male intrusions, which continue during incubation.

  7. Formation of the Si-B bond: insertion reactions of silylenes into B-X(X = F, Cl, Br, O, and N) bonds.

    PubMed

    Geng, Bing; Xu, Chongjuan; Chen, Zhonghe

    2016-06-01

    The insertion reactions of the silylene H2Si with H2BXHn-1 (X = F, Cl, Br, O, N; n = 1, 1, 1, 2, 3) have been studied by DFT and MP2 methods. The calculations show that the insertions occur in a concerted manner, forming H2Si(BH2)(XHn-1). The essences of H2Si insertions with H2BXHn-1 are the transfers of the σ electrons on the Si atom to the positive BH2 group and the electrons of X into the empty p orbital on the Si atom in H2Si. The order of reactivity in vacuum shows the barrier heights increase for the same-family element X from up to down and the same-row element X from right to left in the periodic table. The energies relating to the B-X bond in H2BXHn-1, and the bond energies of Si-X and Si-B in H2Si(BH2)(XHn-1) may determine the preference of insertions of H2Si into B-X bonds for the same-column element X or for the same-row element X. The insertion reactions in vacuum are similar to those in solvents, acetone, ether, and THF. The barriers in vacuum are lower than those in solvents and the larger polarities of solvents make the insertions more difficult to take place. Both in vacuum and in solvents, the silylene insertions are thermodynamically exothermic. Graphical Abstract The insertion process of H2Si and H2BXHn-1(X = F, Cl, Br, O, and N; n = 1, 1 , 1, 2, 3). PMID:27184004

  8. Charge Aspects of Composite Pair Superconductivity

    NASA Astrophysics Data System (ADS)

    Flint, Rebecca

    2014-03-01

    Conventional Cooper pairs form from well-defined electronic quasiparticles, making the internal structure of the pair irrelevant. However, in the 115 family of superconductors, the heavy electrons are forming as they pair and the internal pair structure becomes as important as the pairing mechanism. Conventional spin fluctuation mediated pairing cannot capture the direct transition from incoherent local moments to heavy fermion superconductivity, but the formation of composite pairs favored by the two channel Kondo effect can. These composite pairs are local d-wave pairs formed by two conduction electrons in orthogonal Kondo channels screening the same local moment. Composite pairing shares the same symmetries as magnetically mediated pairing, however, only composite pairing necessarily involves a redistribution of charge within the unit cell originating from the internal pair structure, both as a monopole (valence change) and a quadrupole effect. This redistribution will onset sharply at the superconducting transition temperature. A smoking gun test for composite pairing is therefore a sharp signature at Tc - for example, a cusp in the Mossbauer isomer shift in NpPd5Al2 or in the NQR shift in (Ce,Pu)CoIn5.

  9. The power of paired genomes.

    PubMed

    Gerardo, Nicole M; Wilson, Alex C C

    2011-05-01

    Species interactions are fundamental to ecology. Classic studies of competition, predation, parasitism and mutualism between macroscopic organisms have provided a foundation for the discipline, but many of the most important and intimate ecological interactions are microscopic in scale. These microscopic interactions include those occurring between eukaryotic hosts and their microbial symbionts. Such symbioses, ubiquitous in nature, provide experimental challenges because the partners often cannot live outside the symbiosis. With respect to the symbionts, this precludes utilizing classical microbiological and genetic techniques that require in vitro cultivation. Genomics, however, has rapidly changed the study of symbioses. In this issue of Molecular Ecology, MacDonald et al. (2011), coupling symbiont whole-genome sequencing, experimental studies and metabolic modelling, provide novel insights into one of the best-studied symbioses, that between aphids and their obligate, nutrient-provisioning, intracellular bacteria, Buchnera aphidicola (Fig. 1). MacDonald and colleagues assessed variation in the ability of aphid–Buchnera pairs to thrive on artificial diets missing different amino acids. As shown previously (e.g. Wilkinson & Douglas 2003), aphid–Buchnera pairs can differ in their requirements for external sources of essential amino acids. Such phenotypic variation could result from differences in Buchnera’s amino acid biosynthetic capabilities or in the ability of aphids to interact with their symbionts. Whole-genome sequencing of the Buchnera genomes from four aphid lines with alternate nutritional phenotypes revealed that the environmental nutrients required by the aphid–Buchnera pairs could not be explained by sequence variation in the symbionts. Instead, a novel metabolic modelling approach suggested that much of the variation in nutritional phenotype could be explained by host variation in the capacity to provide necessary nutrient precursors to their

  10. Simultaneous master-slave Omega pairs. [navigation system featuring low cost receiver

    NASA Technical Reports Server (NTRS)

    Burhans, R. W.

    1974-01-01

    Master-slave sequence ordering of the Omega system is suggested as a method of improving the pair geometry for low-cost receiver user benefit. The sequence change will not affect present sophisticated processor users other than require new labels for some pair combinations, but may require worldwide transmitter operators to slightly alter their long-range synchronizing techniques.

  11. Rashba Splitting of Cooper Pairs

    NASA Astrophysics Data System (ADS)

    Shekhter, R. I.; Entin-Wohlman, O.; Jonson, M.; Aharony, A.

    2016-05-01

    We investigate theoretically the properties of a weak link between two superconducting leads, which has the form of a nonsuperconducting nanowire with a strong Rashba spin-orbit coupling caused by an electric field. In the Coulomb-blockade regime of single-electron tunneling, we find that such a weak link acts as a "spin splitter" of the spin states of Cooper pairs tunneling through the link, to an extent that depends on the direction of the electric field. We show that the Josephson current is sensitive to interference between the resulting two transmission channels, one where the spins of both members of a Cooper pair are preserved and one where they are both flipped. As a result, the current is a periodic function of the strength of the spin-orbit interaction and of the bending angle of the nanowire (when mechanically bent); an identical effect appears due to strain-induced spin-orbit coupling. In contrast, no spin-orbit induced interference effect can influence the current through a single weak link connecting two normal metals.

  12. Rashba Splitting of Cooper Pairs.

    PubMed

    Shekhter, R I; Entin-Wohlman, O; Jonson, M; Aharony, A

    2016-05-27

    We investigate theoretically the properties of a weak link between two superconducting leads, which has the form of a nonsuperconducting nanowire with a strong Rashba spin-orbit coupling caused by an electric field. In the Coulomb-blockade regime of single-electron tunneling, we find that such a weak link acts as a "spin splitter" of the spin states of Cooper pairs tunneling through the link, to an extent that depends on the direction of the electric field. We show that the Josephson current is sensitive to interference between the resulting two transmission channels, one where the spins of both members of a Cooper pair are preserved and one where they are both flipped. As a result, the current is a periodic function of the strength of the spin-orbit interaction and of the bending angle of the nanowire (when mechanically bent); an identical effect appears due to strain-induced spin-orbit coupling. In contrast, no spin-orbit induced interference effect can influence the current through a single weak link connecting two normal metals. PMID:27284669

  13. Pair bonds: arrival synchrony in migratory birds.

    PubMed

    Gunnarsson, T G; Gill, J A; Sigurbjörnsson, T; Sutherland, W J

    2004-10-01

    Synchronous arrival of pairs of migratory birds at their breeding grounds is important for maintaining pair bonds and is achieved by pairs that remain together all year round. Here we show that arrival is also synchronized in paired individuals of a migratory shorebird, the black-tailed godwit (Limosa limosa islandica), even though they winter hundreds of kilometres apart and do not migrate together. The mechanisms required to achieve this synchrony and prevent 'divorce' illustrate the complexity of migratory systems. PMID:15470417

  14. Individuation of Pairs of Objects in Infancy

    ERIC Educational Resources Information Center

    Leslie, Alan M.; Chen, Marian L.

    2007-01-01

    Looking-time studies examined whether 11-month-old infants can individuate two pairs of objects using only shape information. In order to test individuation, the object pairs were presented sequentially. Infants were familiarized either with the sequential pairs, disk-triangle/disk-triangle (XY/XY), whose shapes differed within but not across…

  15. The Associability of CVC Pairs. Research Report.

    ERIC Educational Resources Information Center

    Montague, William E.; Kiess, Harold O.

    To obtain an a priori estimate of natural language mediators (NLM's) 320 pairs of words with the consonant-vowel-consonant-pattern (CVC's) were broken into four series of 90 pairs and presented to 240 male and female undergraduates. Pairs were shown for 15 seconds while the subjects wrote down any associative device or NLM they could generate that…

  16. Effects of Habitat Complexity on Pair-Housed Zebrafish.

    PubMed

    Keck, Victoria A; Edgerton, Dale S; Hajizadeh, Susan; Swift, Larry L; Dupont, William D; Lawrence, Christian; Boyd, Kelli L

    2015-07-01

    Sexually mature zebrafish were housed as single male-female pairs with or without plastic vegetation for 1, 5, or 10 d for comparison of whole-body cortisol measured by radioimmunoassay. Individually housed male zebrafish were used as controls. In the fish that were pair-housed without vegetation (NVeg), one animal died in 5 of 24 pairs, and one animal was alive but wounded in an additional pair. No deaths or wounds occurred in the fish that were pair-housed with vegetation (Veg). Cortisol levels did not differ between the treatment groups on day 1. On day 5, cortisol values were higher in the Veg group than in the individually housed fish (P < 0.0005) and the NVeg fish (P = 0.004). On day 10, the relationships were inversed: cortisol levels had risen in the individually housed and NVeg groups and had fallen to baseline levels in the Veg group. Cortisol values on day 10 were lower in the Veg group than in the individually housed (P = 0.004) and NVeg (P = 0.05) groups. Cortisol levels in individually housed male zebrafish increased over time. Although this study did not demonstrate a reduction in cortisol levels associated with providing vegetation, this enrichment prevented injury and death from fighting. These findings show how commonly used housing situations may affect the wellbeing of laboratory zebrafish. PMID:26224437

  17. Pair Production and Annihilation in Strong Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Daugherty, J. K.; Harding, A. K.

    1983-01-01

    Electromagnetic phenomena occurring in the presence of strong magnetic fields are currently of great interest in high-energy astrophysics. In particular, the process of pair production by single photons in the presence of fields of order 10 to the 12th power Gauss is of importance in cascade models of pulsar gamma ray emission, and may also become significant in theories of other radiation phenomena whose sources may be neutron stars (e.g., gamma ray bursts). In addition to pair production, the inverse process of pair annihilation is greatly affected by the presence of superstrong magnetic fields. The most significant departures from annihilation processes in free space are a reduction in the total rate for annihilation into two photons, a broadening of the familiar 511-keV line for annihilation at rest, and the possibility for annihilation into a single photon (which dominates the two-photon annihilation for B ( 10 the 13th power Gauss). The physics of these pair conversion processes, which is reviewed briefly, can become quite complex in the teragauss regime, and can involve calculations which are technically difficult to incorporate into models of emission mechanisms in neutron star magnetospheres. However, theoretical work, especially the case of pair annihilation, also suggests potential techniques for more direct measurements of field strengths near the stellar surface.

  18. Stellar kinematics of elliptical galaxies in pairs

    NASA Technical Reports Server (NTRS)

    Madejsky, Rainer; Bender, Ralf

    1990-01-01

    In both galaxy pairs Arp 166 and 3C 278 the authors find radially increasing velocity dispersions indicating a perturbed, non-equilibrium state of the galaxies after the tidal interaction. In all galaxies, the increase is most pronounced in the regions which correspond to the centers of the outer isophotes. The authors suggest a scenario in which the galaxies are strongly decelerated on their orbits during the encounter. The deceleration depends on the radial position in the perturbed galaxy and vanishes in the center of the perturbed galaxy (Spitzer, 1958). In addition, the crossing time of the stars near the center is very short, implying that the tidal perturbations can be averaged over several orbital periods (e.g., Binney and Tremaine, 1987). In consequence, the central parts are not affected by the tidal interaction while the outer parts are strongly decelerated. This leads to a displacement of the central parts of the galaxies with respect to their envelopes in an anti-symmetrical way for the two components of each galaxy pair. The motions of the central parts subsequently are opposed by dynamical friction with the surrounding envelopes. Due to dynamical friction, the density of the stars increases in the wakes of the moving central parts (Mulder, 1983). The overdensity of stars in the wakes of the moving central parts efficiently decelerates the motions of the central parts. The reaction of the stars in the overdensity regions leads to an increase of the velocity dispersion mainly along the orbits of the moving central parts. The presented observations, especially the asymmetrical luminosity profiles and the radially increasing velocity dispersions support consistently the above scenario of tidal interaction between galaxies. Further spectroscopic observations are necessary in order to investigate the degree of anisotropy in the kinematically perturbed regions.

  19. Large-amplitude pairing fluctuations in atomic nuclei

    NASA Astrophysics Data System (ADS)

    Vaquero, Nuria López; Egido, J. Luis; Rodríguez, Tomás R.

    2013-12-01

    Pairing fluctuations are self-consistently incorporated on the same footing as the quadrupole deformations in present state-of-the-art calculations including particle-number and angular-momentum conservation as well as configuration mixing. The approach is complemented by the use of the finite-range density-dependent Gogny force which, with a unique source for the particle-hole and particle-particle interactions, guarantees a self-consistent interplay in both channels. We have applied our formalism to study the role of the pairing degree of freedom in the description of the most relevant observables like spectra, transition probabilities, separation energies, etc. We find that the inclusion of pairing fluctuations mostly affects the description of excited states, depending on the excitation energy and the angular momentum. E0 transition probabilities experience rather big changes while E2's are less affected. Genuine pairing vibrations are thoroughly studied with the conclusion that deformations strongly inhibits their existence. These studies have been performed for a selection of nuclei: spherical, deformed, and with different degrees of collectivity.

  20. Affective Learning.

    ERIC Educational Resources Information Center

    Brown, Charles T.

    This paper addresses itself to the question, "What does feeling have to do with knowing?" Two movements in affective education are discussed which have come into focus in recent years and which attempt to define the relationship between knowing and feeling. The first, a conscious application of the role of arousal in learning, emphasizes arousal…

  1. Perturbations of vortex ring pairs

    NASA Astrophysics Data System (ADS)

    Gubser, Steven S.; Horn, Bart; Parikh, Sarthak

    2016-02-01

    We study pairs of coaxial vortex rings starting from the action for a classical bosonic string in a three-form background. We complete earlier work on the phase diagram of classical orbits by explicitly considering the case where the circulations of the two vortex rings are equal and opposite. We then go on to study perturbations, focusing on cases where the relevant four-dimensional transfer matrix splits into two-dimensional blocks. When the circulations of the rings have the same sign, instabilities are mostly limited to wavelengths smaller than a dynamically generated length scale at which single-ring instabilities occur. When the circulations have the opposite sign, larger wavelength instabilities can occur.

  2. Deletion of small nuclear ribonucleoprotein polypeptide N (SNRPN) in Prader-Willi syndrome detected by fluorescence in situ hybridization: Two sibs with the typical phenotype without a cytogenetic deletion in chromosome 15q

    SciTech Connect

    Ishikawa, Tatsuya; Kibe, Tetsuya; Wada, Yoshiro

    1996-04-24

    The small nuclear ribonucleoprotein polypeptide N (SNRPN) gene is regarded as one of the candidates for Prader-Willi syndrome (PWS). We describe two sibs with typical PWS presenting deletion of SNRPN detected by fluorescence in situ hybridization (FISH). Neither a cytogenetically detectable 15q12 deletion nor a deletion for the D15S11, D15S10, and GABRB3 cosmid probes were found in either patient. This implies a smaller deletion limited to the PWS critical region. FISH with a SNRPN probe will permit analysis of PWS patients with limited deletions not detectable with other probes. 22 refs., 1 fig.

  3. Paired States of Composite Fermions

    NASA Astrophysics Data System (ADS)

    Bonesteel, N. E.

    2002-03-01

    There is compelling theoretical evidence(R. Morf, Phys. Rev. Lett. 80), 1505 (1998). that the ν=5/2 fractional quantum Hall state is a Moore-Read state(G. Moore and N. Read, Nucl. Phys. B 360), 362 (1991). -- a state which can be viewed as a spin-polarized p-wave `superconductor' of composite fermions. The question remains, how can one test this hypothesis experimentally? To address this we have developed a semi-phenomenological description of this state in which the Halperin-Lee-Read(B.I. Halperin, P.A. Lee, and N. Read, Phys. Rev. B 47), 7312 (1993). theory of the half-filled Landau level is modified by adding a p-wave pairing interaction between composite fermions by hand. The electromagnetic response functions for the resulting mean-field superconducting state are then calculated and used in an RPA calculation of the physical electronic response. For a clean enough sample, and for q << k_f, the transverse electromagnetic response function for composite fermions is governed by type-II coherence factors and shows a `Hebel-Slichter'-like peak as a function of temperature for low enough frequency. The possibility (and potential difficulties) of observing this peak indirectly in surface-acoustic-wave propagation experiments will be discussed. The observation of such a coherence peak would provide strong evidence of BCS pairing in the 5/2 state. Work supported by US DOE Grant No. DE-FG02-97ER45639. Work done in collaboration with K.C. Foster (FSU) and S.H. Simon (Lucent). note

  4. The road not taken: life experiences in monozygotic twin pairs discordant for major depression

    PubMed Central

    Kendler, KS; Halberstadt, LJ

    2012-01-01

    In an effort to understand how environmental experiences contribute to risk for major depression (MD), we conducted joint autobiographical interviews with 14 pairs of monozygotic twins (mean age 51.2) rigorously discordant for a lifetime history of MD. Twelve of the pairs could be sorted into four broad categories. In two pairs, discordance was associated with a single traumatic event occurring to the affected twin. In seven pairs, the well twin had one stable, long-term, successful romantic relationship, whereas the affected co-twin had romantic reversals one or more of which precipitated depressive episodes. These pairs varied in the degree to which the romantic problems seemed to arise from bad luck or poor choices. In one pair, occupational difficulties were strongly related to discordance in experiences with MD. In two pairs, several mechanisms seemed to be at work. Discordance in the quality of intimate love relationships was the most common etiological factor revealed by interview in these discordant pairs, with single dramatic events and occupational problems being considerably rarer. Even in this best of natural experiments, the causal interrelationship between personality, environment and depressive episodes was not always clear. Many pairs illustrated the protective effects of planfulness and the malignant effect of cumulative continuity where early difficulties in relationships shaped the subsequent life course. These results speak both to the importance of environmental influences on human well-being and psychopathology, and the complexity of the causal paths underlying their effects. PMID:22641178

  5. Top quark pair production cross section at the Tevatron

    SciTech Connect

    Cortiana, Giorgio; /INFN, Padua /Padua U.

    2008-04-01

    Top quark pair production cross section has been measured at the Tevatron by CDF and D0 collaborations using different channels and methods, in order to test standard model predictions, and to search for new physics hints affecting the t{bar t} production mechanism or decay. Measurements are carried out with an integrated luminosity of 1.0 to 2.0 fb{sup -1}, and are found to be consistent with standard model expectations.

  6. Report on Pairing-based Cryptography

    PubMed Central

    Moody, Dustin; Peralta, Rene; Perlner, Ray; Regenscheid, Andrew; Roginsky, Allen; Chen, Lily

    2015-01-01

    This report summarizes study results on pairing-based cryptography. The main purpose of the study is to form NIST’s position on standardizing and recommending pairing-based cryptography schemes currently published in research literature and standardized in other standard bodies. The report reviews the mathematical background of pairings. This includes topics such as pairing-friendly elliptic curves and how to compute various pairings. It includes a brief introduction to existing identity-based encryption (IBE) schemes and other cryptographic schemes using pairing technology. The report provides a complete study of the current status of standard activities on pairing-based cryptographic schemes. It explores different application scenarios for pairing-based cryptography schemes. As an important aspect of adopting pairing-based schemes, the report also considers the challenges inherent in validation testing of cryptographic algorithms and modules. Based on the study, the report suggests an approach for including pairing-based cryptography schemes in the NIST cryptographic toolkit. The report also outlines several questions that will require further study if this approach is followed. PMID:26958435

  7. Report on Pairing-based Cryptography.

    PubMed

    Moody, Dustin; Peralta, Rene; Perlner, Ray; Regenscheid, Andrew; Roginsky, Allen; Chen, Lily

    2015-01-01

    This report summarizes study results on pairing-based cryptography. The main purpose of the study is to form NIST's position on standardizing and recommending pairing-based cryptography schemes currently published in research literature and standardized in other standard bodies. The report reviews the mathematical background of pairings. This includes topics such as pairing-friendly elliptic curves and how to compute various pairings. It includes a brief introduction to existing identity-based encryption (IBE) schemes and other cryptographic schemes using pairing technology. The report provides a complete study of the current status of standard activities on pairing-based cryptographic schemes. It explores different application scenarios for pairing-based cryptography schemes. As an important aspect of adopting pairing-based schemes, the report also considers the challenges inherent in validation testing of cryptographic algorithms and modules. Based on the study, the report suggests an approach for including pairing-based cryptography schemes in the NIST cryptographic toolkit. The report also outlines several questions that will require further study if this approach is followed. PMID:26958435

  8. Galaxy pairs align with Galactic filaments

    NASA Astrophysics Data System (ADS)

    Tempel, E.; Tamm, A.

    2015-04-01

    Context. Gravitational collapse theory and numerical simulations suggest that the velocity field within large-scale galaxy filaments is dominated by motions along the filaments. Aims: Our aim is to check whether observational data reveal any preferred orientation of galaxy pairs with respect to the underlying filaments as a result of the expectedly anisotropic velocity field. Methods: We use galaxy pairs and galaxy filaments identified from Sloan Digital Sky Survey data. For filament extraction, we use the Bisous model that is based on the marked point process technique. During the filament detection, we use the centre point of each pair instead of the positions of galaxies to avoid a built-in influence of pair orientation on the filament construction. For pairs lying within filaments (3012 cases), we calculate the angle between the line connecting the galaxies of each pair and their host filaments. To avoid redshift-space distortions, the angle is measured in the plane of the sky. Results: The alignment analysis shows that the orientation of galaxy pairs correlates strongly with their host filaments. The alignment signal is stronger for loose pairs, with at least 25% excess of aligned pairs compared to a random distribution. The alignment of galaxy pairs and filaments measured from the observational data is in good agreement with the alignment in the Millennium simulation and thus provides support to the ΛCDM formalism.

  9. FIR statistics of paired galaxies

    NASA Technical Reports Server (NTRS)

    Sulentic, Jack W.

    1990-01-01

    Much progress has been made in understanding the effects of interaction on galaxies (see reviews in this volume by Heckman and Kennicutt). Evidence for enhanced emission from galaxies in pairs first emerged in the radio (Sulentic 1976) and optical (Larson and Tinsley 1978) domains. Results in the far infrared (FIR) lagged behind until the advent of the Infrared Astronomy Satellite (IRAS). The last five years have seen numerous FIR studies of optical and IR selected samples of interacting galaxies (e.g., Cutri and McAlary 1985; Joseph and Wright 1985; Kennicutt et al. 1987; Haynes and Herter 1988). Despite all of this work, there are still contradictory ideas about the level and, even, the reality of an FIR enhancement in interacting galaxies. Much of the confusion originates in differences between the galaxy samples that were studied (i.e., optical morphology and redshift coverage). Here, the authors report on a study of the FIR detection properties for a large sample of interacting galaxies and a matching control sample. They focus on the distance independent detection fraction (DF) statistics of the sample. The results prove useful in interpreting the previously published work. A clarification of the phenomenology provides valuable clues about the physics of the FIR enhancement in galaxies.

  10. Pair programming in education: a literature review

    NASA Astrophysics Data System (ADS)

    Hanks, Brian; Fitzgerald, Sue; McCauley, Renée; Murphy, Laurie; Zander, Carol

    2011-06-01

    This article provides a review of educational research literature focused on pair programming in the undergraduate computer science curriculum. Research suggests that the benefits of pair programming include increased success rates in introductory courses, increased retention in the major, higher quality software, higher student confidence in solutions, and improvement in learning outcomes. Moreover, there is some evidence that women, in particular, benefit from pair programming. The literature also provides evidence that the transition from paired to solo programming is easy for students. The greatest challenges for paired students appear to concern scheduling and partner compatibility. This review also considers practical issues such as assigning partners, teaching students to work in pairs, and assessing individual contributions, and concludes with a discussion of open research questions.

  11. Lax pairs for deformed Minkowski spacetimes

    NASA Astrophysics Data System (ADS)

    Kyono, Hideki; Sakamoto, Jun-ichi; Yoshida, Kentaroh

    2016-01-01

    We proceed to study Yang-Baxter deformations of 4D Minkowski spacetime based on a conformal embedding. We first revisit a Melvin background and argue a Lax pair by adopting a simple replacement law invented in 1509.00173. This argument enables us to deduce a general expression of Lax pair. Then the anticipated Lax pair is shown to work for arbitrary classical r-matrices with Poincaré generators. As other examples, we present Lax pairs for pp-wave backgrounds, the Hashimoto-Sethi background, the Spradlin-Takayanagi-Volovich background.

  12. Genetic mapping of quantitative trait loci affecting susceptibility in chicken to develop pulmonary hypertension syndrome.

    PubMed

    Rabie, T S K M; Crooijmans, R P M A; Bovenhuis, H; Vereijken, A L J; Veenendaal, T; van der Poel, J J; Van Arendonk, J A M; Pakdel, A; Groenen, M A M

    2005-12-01

    Pulmonary hypertension syndrome (PHS), also referred to as ascites syndrome, is a growth-related disorder of chickens frequently observed in fast-growing broilers with insufficient pulmonary vascular capacity at low temperature and/or at high altitude. A cross between two genetically different broiler dam lines that originated from the White Plymouth Rock breed was used to produce a three-generation population. This population was used for the detection and localization of quantitative trait loci (QTL) affecting PHS-related traits. Ten full-sib families consisting of 456 G2 birds were typed with 420 microsatellite markers covering 24 autosomal chromosomes. Phenotypic observations were collected on 4202 G3 birds and a full-sib across family regression interval mapping approach was used to identify QTL. There was statistical evidence for QTL on chicken chromosome 2 (GGA2), GGA4 and GGA6. Suggestive QTL were found on chromosomes 5, 8, 10, 27 and 28. The most significant QTL were located on GGA2 for right and total ventricular weight as percentage of body weight (%RV and %TV respectively). A related trait, the ratio of right ventricular weight as percentage to total ventricular weight (RATIO), reached the suggestive threshold on this chromosome. All three QTL effects identified on GGA2 had their maximum test statistic in the region flanked by markers MCW0185 and MCW0245 (335-421 cM). PMID:16293119

  13. Resonance effects indicate radical pair mechanism for avian magnetic compass

    NASA Astrophysics Data System (ADS)

    Ritz, Thorsten

    2005-03-01

    Migratory birds possess a physiological magnetic compass that helps them to find north during their migratory flights, but the mechanism underlying this ability is not understood. In vitro experiments show that two types of mechanisms are in principle capable of detecting earth-strength magnetic fields in biological systems: the use of biological magnetic materials such as magnetite crystals, or magnetically sensitive chemical reactions. We have recently demonstrated that oscillating magnetic fields can provide a viable diagnostic test to identify the existence of a radical-pair mechanism as they will not affect the properties of magnetite-based sensors, but disrupt a radical-pair based mechanism through resonance effects. European robins, a species of migratory birds, were disoriented in a magnetic orientation test when a very weak (100 nT) oscillating field of 1.3 or 7 MHz was added to the geomagnetic field. Moreover, the effect of the oscillating field depended on the alignment of oscillating field with the geomagnetic field and showed an intensity dependence consistent with theoretical expectations from the radical pair mechanism, thereby providing evidence for the existence of a radical-pair mechanism in birds. We will discuss future avenues of research towards identifying not only the mechanism, but also the chemical nature of the receptors underlying magnetoreception, and in particular the photoreceptor chryptochrome, an emerging candidate for the long sought after magnetoreceptor.

  14. Meiotic chromosome pairing in triploid and tetraploid Saccharomyces cerevisiae

    SciTech Connect

    Loidl, J.

    1995-04-01

    Meiotic chromosome pairing in isogenic triploid and tetraploid strains of yeast and the consequences of polyploidy on meiotic chromosome segregation are studied. Synaptonemal complex formation at pachytene was found to be different in the triploid and in the tetraploid. In the triploid, triple-synapsis, that is, the connection of three homologues at a given site, is common. It can even extend all the way along the chromosomes. In the tetraploid, homologous chromosomes mostly come in pairs of synapsed bivalents. Multiple synapsis, that is, synapsis of more than two homologues in one and the same region, was virtually absent in the tetraploid. About five quadrivalents per cell occurred due to the switching of pairing partners. From the frequency of pairing partner switches it can be deduced that in most chromosomes synapsis is initiated primarily at one end, occasionally at both ends and rarely at an additional intercalary position. In contrast to a considerably reduced spore viability ({approximately}40%) in the triploid, spore viability is only mildly affected in the tetraploid. The good spore viability is presumably due to the low frequency of quadrivalents and to the highly regular 2:2 segregation of the few quadrivalents that do occur. Occasionally, however, quadrivalents appear to be subject to 3:1 nondisjunction that leads to spore death in the second generation. 29 refs., 6 figs., 4 tabs.

  15. Synthesis, base pairing and structure studies of geranylated RNA.

    PubMed

    Wang, Rui; Vangaveti, Sweta; Ranganathan, Srivathsan V; Basanta-Sanchez, Maria; Haruehanroengra, Phensinee; Chen, Alan; Sheng, Jia

    2016-07-27

    Natural RNAs utilize extensive chemical modifications to diversify their structures and functions. 2-Thiouridine geranylation is a special hydrophobic tRNA modification that has been discovered very recently in several bacteria, such as Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa and Salmonella Typhimurium The geranylated residues are located in the first anticodon position of tRNAs specific for lysine, glutamine and glutamic acid. This big hydrophobic terpene functional group affects the codon recognition patterns and reduces frameshifting errors during translation. We aimed to systematically study the structure, function and biosynthesis mechanism of this geranylation pathway, as well as answer the question of why nature uses such a hydrophobic modification in hydrophilic RNA systems. Recently, we have synthesized the deoxy-analog of S-geranyluridine and showed the geranylated T-G pair is much stronger than the geranylated T-A pair and other mismatched pairs in the B-form DNA duplex context, which is consistent with the observation that the geranylated tRNA(Glu) UUC recognizes GAG more efficiently than GAA. In this manuscript we report the synthesis and base pairing specificity studies of geranylated RNA oligos. We also report extensive molecular simulation studies to explore the structural features of the geranyl group in the context of A-form RNA and its effect on codon-anticodon interaction during ribosome binding. PMID:27307604

  16. [Affective dependency].

    PubMed

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy. PMID:23888587

  17. Widnall instabilities in vortex pairs

    NASA Astrophysics Data System (ADS)

    Sipp, Denis; Jacquin, Laurent

    2003-07-01

    In this article we analyze the cooperative three-dimensional short-wave instabilities developing on concentrated vortex dipoles that have been obtained by means of two-dimensional direct numerical simulations. These dipoles are characterized by their aspect ratio a/b where a is the radius of the vortices based on the polar moments of vorticity and b is the separation between the vortex centroids. In the inviscid case, we show that the selection of the antisymmetric eigenmode smoothly increases with a/b: for a/b=0.208, the amplification rate of the antisymmetric eigenmode is only 1.4% larger than the amplification rate of the symmetric eigenmode. When a/b=0.288, this difference increases up to 7%. The results of the normal mode analysis may be compared to those of an asymptotic stability analysis of a Lamb-Oseen vortex subjected to a weak straining field, following Moore and Saffman [Proc. R. Soc. London, Ser. A 346, 413 (1975)]. This theory shows that the instability may occur whenever two Kelvin waves exist with the same frequency ω, the same axial wavenumber k and with azimuthal wavenumbers m and m+2. Contrary to the case of a Rankine vortex [Tsai and Widnall, J. Fluid Mech. 73, 721 (1976)], the presence of critical layers in a Lamb-Oseen vortex prevents a large number of possible resonances. For example, resonances between m=-2 and m=0 modes lead to damped modes. The only resonances that occur are related to the stationary (ω=0) bending waves (m=±1) obtained for specific values of the axial wavenumber. All these predictions are found to be in good agreement with the results obtained by the stability analysis of the considered vortex pairs. At last, we present a nonautonomous amplitude equation which takes into account all effects of viscosity, i.e., the viscous damping of the amplification rate of the perturbation but also the increase of the dipole aspect ratio a/b due to the viscous diffusion of the basic flowfield. The low-Reynolds number experiment of

  18. Top Quark Pair Production at the Tevatron

    SciTech Connect

    Nielsen, Jason

    2005-05-17

    The measurement of the top quark pair production crosssection inproton-antiproton collisions at 1.96 TeV is a test ofquantumchromodynamics and could potentially be sensitive to newphysics beyondthe standard model. I report on the latest t-tbarcross section resultsfrom the CDF and DZero experiments in various finalstate topologies whicharise from decays of top quark pairs.

  19. Attitudes on Using Pair-Programming

    ERIC Educational Resources Information Center

    Howard, Elizabeth V.

    2007-01-01

    During a research study conducted over four semesters, students enrolled in an introductory programming class at a commuter campus used the pair-programming approach for both in-class labs and out-of-class programming assignments. This study was a comprehensive assessment of pair-programming using multiple measures of both quantitative and…

  20. Paired Placements for Early Field Experiences

    ERIC Educational Resources Information Center

    Cohen, Myrna D.; Nath, Janice L.

    2006-01-01

    This article describes and evaluates the pairing of 2 preservice teachers to 1 mentor for early fieldwork. Traditionally, many programs have been reluctant to assign more than 1 student to a mentor. This study describes how the pairing is implemented; it addresses practical considerations; and it evaluates the innovation. Feedback gathered from…

  1. Pairing, pseudogap and Fermi arcs in cuprates

    SciTech Connect

    Kaminski, Adam; Kondo, Takeshi; Takeuchi, Tsunehiro; Gu, Genda

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scattering creates “artificial” Fermi arcs for Tc ≤ T ≤ Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. As a result, we demonstrate that these findings resolve a number of seemingly contradictory scenarios.

  2. Pair Programming in Education: A Literature Review

    ERIC Educational Resources Information Center

    Hanks, Brian; Fitzgerald, Sue; McCauley, Renee; Murphy, Laurie; Zander, Carol

    2011-01-01

    This article provides a review of educational research literature focused on pair programming in the undergraduate computer science curriculum. Research suggests that the benefits of pair programming include increased success rates in introductory courses, increased retention in the major, higher quality software, higher student confidence in…

  3. Fundamental pairs in nuclear collective motion

    NASA Astrophysics Data System (ADS)

    Naotaka, Yoshinaga

    1994-03-01

    Usefulness of the pair approximation is shown in both vibrational and rotational regions. The renormalized SDG-pair space is sufficiently enough to reproduce moment of inertia of the ground band that was previously thought as a difficult physical quantity to be reproduced.

  4. Paired Reading Bulletin. Spring 1988, No. 4.

    ERIC Educational Resources Information Center

    Paired Reading Bulletin, 1988

    1988-01-01

    The annual bulletin of the Paired Reading Project contains 17 feature articles: (1) "Parental Involvement in Reading and Language" (F. Burton); (2) "Infant/Infant Cross-Age Peer Group Tuition" (A. Low and M.Davies); (3) "Comment on Low & Davies" (K. Topping); (4) "Paired Reading in Reaside Middle School" (F. Gautrey); (5) "Sex Differences in the…

  5. Pairing in a dry Fermi sea.

    PubMed

    Maier, T A; Staar, P; Mishra, V; Chatterjee, U; Campuzano, J C; Scalapino, D J

    2016-01-01

    In the traditional Bardeen-Cooper-Schrieffer theory of superconductivity, the amplitude for the propagation of a pair of electrons with momentum k and -k has a log singularity as the temperature decreases. This so-called Cooper instability arises from the presence of an electron Fermi sea. It means that an attractive interaction, no matter how weak, will eventually lead to a pairing instability. However, in the pseudogap regime of the cuprate superconductors, where parts of the Fermi surface are destroyed, this log singularity is suppressed, raising the question of how pairing occurs in the absence of a Fermi sea. Here we report Hubbard model numerical results and the analysis of angular-resolved photoemission experiments on a cuprate superconductor. In contrast to the traditional theory, we find that in the pseudogap regime the pairing instability arises from an increase in the strength of the spin-fluctuation pairing interaction as the temperature decreases rather than the Cooper log instability. PMID:27312569

  6. Pairing in a dry Fermi sea

    NASA Astrophysics Data System (ADS)

    Maier, T. A.; Staar, P.; Mishra, V.; Chatterjee, U.; Campuzano, J. C.; Scalapino, D. J.

    2016-06-01

    In the traditional Bardeen-Cooper-Schrieffer theory of superconductivity, the amplitude for the propagation of a pair of electrons with momentum k and -k has a log singularity as the temperature decreases. This so-called Cooper instability arises from the presence of an electron Fermi sea. It means that an attractive interaction, no matter how weak, will eventually lead to a pairing instability. However, in the pseudogap regime of the cuprate superconductors, where parts of the Fermi surface are destroyed, this log singularity is suppressed, raising the question of how pairing occurs in the absence of a Fermi sea. Here we report Hubbard model numerical results and the analysis of angular-resolved photoemission experiments on a cuprate superconductor. In contrast to the traditional theory, we find that in the pseudogap regime the pairing instability arises from an increase in the strength of the spin-fluctuation pairing interaction as the temperature decreases rather than the Cooper log instability.

  7. The effect of temperature and pairing on nuclear pseudospin symmetry

    SciTech Connect

    Malheiro, M.; Lisboa, R.; Carlson, B. V.; Alberto, P.

    2009-06-03

    We study the effects of temperature andpairing on pseudospin symmetry in spherical and deformed nucleus using the Dirac-Hartree-Bogoliubov (DHB) formalism. We include temperature in the DHB equation using the Matsubara formalism and analyze changes in the neutron single particle levels with the temperature. We show that the effect of temperature on the pseudospin energy splitting is small. We find that this splitting decreases at high temperatures and that pseudospin partners are almost degenerate in deformed hot nuclei, indicating the dependence of pseudospin symmetry on the nuclear surface. Furthermore, for reasonable values of the pairing interaction, we also show that pairing does not affect the pseudospin symmetry in deformed nuclei. Finally, we find that the effect of temperature on pseudospin doublets is more pronounced in spherical nuclei than in deformed ones.

  8. The kink-pair nucleation in edge dislocation motion

    NASA Astrophysics Data System (ADS)

    Yu, Song; Wang, Chong-Yu; Yu, Tao

    2009-03-01

    The motion of edge dislocations (EDs) and kinked EDs in body-centered cubic Fe are studied at atom level. We find the kink-pair nucleation mechanism directly from the atom configuration evolution of dislocation, the EDs move primarily by the kink-pair nucleation, and the pre-existing kink does not affect this motion mode. The result is in agreement with the energy calculation. Furthermore, the Peierls stress, dislocation velocity, and phonon-drag coefficient are discussed. There are obviously two motion regions with different stresses. In the low-stress region, the stress exercises a great influence on the dislocation motion, the dislocation velocity increase significantly with the increase of stress. In the high-stress region, however, phonon drag practice a dominant factor on the dislocation motion, the dislocation move with approximately constant speed close to the transverse speed of sound.

  9. Optical Spectroscopy of Unbound Asteroid Pairs

    NASA Astrophysics Data System (ADS)

    Duddy, Samuel; Lowry, S. C.; Christou, A.; Wolters, S. D.; Snodgrass, C.; Fitzsimmons, A.; Deller, J. F.; Hainaut, O. R.; Rozitis, B.; Weissman, P. R.; Green, S. F.

    2012-10-01

    The recently discovered unbound asteroid pairs have been suggested to be the result of the decoupling of binary asteroids formed either through collision processes or, more likely, rotational fission of a rubble-pile asteroid after spin-up (Vokrouhlicky et al. 2008, AJ 136, 280; Pravec et al., 2010, Nature, 466, 1085). Much of the evidence for linkage of the asteroids in each pair relies solely on the backwards integrations of their orbits. We report new results from our continuing spectroscopic survey of the unbound asteroid pairs, including the youngest known pair, (6070) Rhineland - (54827) 2001 NQ8. The survey goal is to determine whether the asteroids in each unbound pair have similar spectra and therefore composition, expected if they have formed from a common parent body. Low-resolution spectroscopy covering the range 0.4-0.95 microns was conducted using the 3.6m ESO NTT+EFOSC2 during 2011-2012 and the 4.2m WHT+ACAM. We have attempted to maintain a high level of consistency between the observations of the components in each pair to ensure that differences in the asteroid spectra are not the result of the observing method or data reduction, but purely caused by compositional differences. Our WHT data indicates that the asteroids of unbound pair 17198 - 229056 exhibit different spectra and have been assigned different taxonomies, A and R respectively. Initial analysis of our data from the NTT suggests that the asteroids in unbound pairs 6070 - 54827 and 38707 - 32957 are likely silicate-dominated asteroids. The components of pair 23998 - 205383 are potentially X-type asteroids. We present final taxonomic classifications and the likelihood of spectral similarity in each pair.

  10. RELAXATION OF BLAZAR-INDUCED PAIR BEAMS IN COSMIC VOIDS

    SciTech Connect

    Miniati, Francesco; Elyiv, Andrii

    2013-06-10

    The stability properties of a low-density ultrarelativistic pair beam produced in the intergalactic medium (IGM) by multi-TeV gamma-ray photons from blazars are analyzed. The problem is relevant for probes of magnetic field in cosmic voids through gamma-ray observations. In addition, dissipation of such beams could considerably affect the thermal history of the IGM and structure formation. We use a Monte Carlo method to quantify the properties of the blazar-induced electromagnetic shower, in particular the bulk Lorentz factor and the angular spread of the pair beam generated by the shower, as a function of distance from the blazar itself. We then use linear and nonlinear kinetic theory to study the stability of the pair beam against the growth of electrostatic plasma waves, employing the Monte Carlo results for our quantitative estimates. We find that the fastest growing mode, like any perturbation mode with even a very modest component perpendicular to the beam direction, cannot be described in the reactive regime. Due to the effect of nonlinear Landau damping, which suppresses the growth of plasma oscillations, the beam relaxation timescale is found to be significantly longer than the inverse Compton loss time. Finally, density inhomogeneities associated with cosmic structure induce loss of resonance between the beam particles and plasma oscillations, strongly inhibiting their growth. We conclude that relativistic pair beams produced by blazars in the IGM are stable on timescales that are long compared with the electromagnetic cascades. There appears to be little or no effect of pair beams on the IGM.

  11. Relaxation of Blazar-induced Pair Beams in Cosmic Voids

    NASA Astrophysics Data System (ADS)

    Miniati, Francesco; Elyiv, Andrii

    2013-06-01

    The stability properties of a low-density ultrarelativistic pair beam produced in the intergalactic medium (IGM) by multi-TeV gamma-ray photons from blazars are analyzed. The problem is relevant for probes of magnetic field in cosmic voids through gamma-ray observations. In addition, dissipation of such beams could considerably affect the thermal history of the IGM and structure formation. We use a Monte Carlo method to quantify the properties of the blazar-induced electromagnetic shower, in particular the bulk Lorentz factor and the angular spread of the pair beam generated by the shower, as a function of distance from the blazar itself. We then use linear and nonlinear kinetic theory to study the stability of the pair beam against the growth of electrostatic plasma waves, employing the Monte Carlo results for our quantitative estimates. We find that the fastest growing mode, like any perturbation mode with even a very modest component perpendicular to the beam direction, cannot be described in the reactive regime. Due to the effect of nonlinear Landau damping, which suppresses the growth of plasma oscillations, the beam relaxation timescale is found to be significantly longer than the inverse Compton loss time. Finally, density inhomogeneities associated with cosmic structure induce loss of resonance between the beam particles and plasma oscillations, strongly inhibiting their growth. We conclude that relativistic pair beams produced by blazars in the IGM are stable on timescales that are long compared with the electromagnetic cascades. There appears to be little or no effect of pair beams on the IGM.

  12. Stereo Pair: Wellington, New Zealand

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Wellington, the capital city of New Zealand, is located on the shores of Port Nicholson, a natural harbor at the south end of North Island. The city was founded in 1840 by British emigrants and now has a regional population of more than 400,000 residents. As seen here, the natural terrain imposes strong control over the urban growth pattern (urban features generally appear gray or white in this view). Rugged hills generally rising to 300 meters (1,000 feet) help protect the city and harbor from strong winter winds

    New Zealand is seismically active and faults are readily seen in the topography. The Wellington Fault forms the straight northwestern (left) shoreline of the harbor. Toward the southwest (down) the fault crosses through the city, then forms linear canyons in the hills before continuing offshore at the bottom. Toward the northeast (upper right) the fault forms the sharp mountain front along the northern edge of the heavily populated Hutt Valley.

    This stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with an enhanced true color Landsat7 satellite image. The topography data are used to create two differing perspectives of a single image, one perspective for each eye. In doing so, each point in the image is shifted slightly, depending on its elevation. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.

    Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30 meter (99 foot) spatial resolution of most Landsat images and will provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) data Center, Sioux Falls, South Dakota.

    Elevation data

  13. SRTM Stereo Pair: Fiji Islands

    NASA Technical Reports Server (NTRS)

    2000-01-01

    image pair and viewing them with a stereoscope. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.

    This image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (about 200 feet) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

    Size: 192 km (119 miles) x 142 km (88 miles) Location: 17.8 deg. South lat., 178.0 deg. East lon. Orientation: North at top Date Acquired: February 19, 2000 Image: NASA/JPL/NIMA

  14. Photon pair generation in multimode optical fibers via intermodal phase matching

    NASA Astrophysics Data System (ADS)

    Pourbeyram, Hamed; Mafi, Arash

    2016-08-01

    We present a detailed study of photon pair generation in a multimode optical fiber via nonlinear four-wave mixing and intermodal phase matching. We show that in multimode optical fibers, it is possible to generate correlated photon pairs in different fiber modes with large spectral shifts from the pump wavelength, such that the photon pairs are immune to contamination from spontaneous Raman scattering and residual pump photons. We also show that it is possible to generate factorable two-photon states exhibiting minimal spectral correlations between the photon pair components in conventional multimode fibers using commonly available pump lasers. It is also possible to simultaneously generate multiple factorable states from different FWM processes in the same fiber and over a wide range of visible spectrum by varying the pump wavelength without affecting the factorability of the states. Therefore, photon pair generation in multimode optical fibers exhibits considerable potential for producing state engineered photons for quantum communications and quantum information processing applications.

  15. A cohesin-based structural platform supporting homologous chromosome pairing in meiosis.

    PubMed

    Ding, Da-Qiao; Haraguchi, Tokuko; Hiraoka, Yasushi

    2016-08-01

    The pairing and recombination of homologous chromosomes during the meiotic prophase is necessary for the accurate segregation of chromosomes in meiosis. However, the mechanism by which homologous chromosomes achieve this pairing has remained an open question. Meiotic cohesins have been shown to affect chromatin compaction; however, the impact of meiotic cohesins on homologous pairing and the fine structures of cohesion-based chromatin remain to be determined. A recent report using live-cell imaging and super-resolution microscopy demonstrated that the lack of meiotic cohesins alters the chromosome axis structures and impairs the pairing of homologous chromosomes. These results suggest that meiotic cohesin-based chromosome axis structures are crucial for the pairing of homologous chromosomes. PMID:26856595

  16. Processing negative valence of word pairs that include a positive word.

    PubMed

    Itkes, Oksana; Mashal, Nira

    2016-09-01

    Previous research has suggested that cognitive performance is interrupted by negative relative to neutral or positive stimuli. We examined whether negative valence affects performance at the word or phrase level. Participants performed a semantic decision task on word pairs that included either a negative or a positive target word. In Experiment 1, the valence of the target word was congruent with the overall valence conveyed by the word pair (e.g., fat kid). As expected, response times were slower in the negative condition relative to the positive condition. Experiment 2 included target words that were incongruent with the overall valence of the word pair (e.g., fat salary). Response times were longer for word pairs whose overall valence was negative relative to positive, even though these word pairs included a positive word. Our findings support the Cognitive Primacy Hypothesis, according to which emotional valence is extracted after conceptual processing is complete. PMID:26008637

  17. Partitioning of on-demand electron pairs

    NASA Astrophysics Data System (ADS)

    Ubbelohde, Niels; Hohls, Frank; Kashcheyevs, Vyacheslavs; Wagner, Timo; Fricke, Lukas; Kästner, Bernd; Pierz, Klaus; Schumacher, Hans W.; Haug, Rolf J.

    2015-01-01

    The on-demand generation and separation of entangled photon pairs are key components of quantum information processing in quantum optics. In an electronic analogue, the decomposition of electron pairs represents an essential building block for using the quantum state of ballistic electrons in electron quantum optics. The scattering of electrons has been used to probe the particle statistics of stochastic sources in Hanbury Brown and Twiss experiments and the recent advent of on-demand sources further offers the possibility to achieve indistinguishability between multiple sources in Hong-Ou-Mandel experiments. Cooper pairs impinging stochastically at a mesoscopic beamsplitter have been successfully partitioned, as verified by measuring the coincidence of arrival. Here, we demonstrate the splitting of electron pairs generated on demand. Coincidence correlation measurements allow the reconstruction of the full counting statistics, revealing regimes of statistically independent, distinguishable or correlated partitioning, and have been envisioned as a source of information on the quantum state of the electron pair. The high pair-splitting fidelity opens a path to future on-demand generation of spin-entangled electron pairs from a suitably prepared two-electron quantum-dot ground state.

  18. Weird Stellar Pair Puzzles Scientists

    NASA Astrophysics Data System (ADS)

    2008-05-01

    Astronomers have discovered a speedy spinning pulsar in an elongated orbit around an apparent Sun-like star, a combination never seen before, and one that has them puzzled about how the strange system developed. Orbital Comparison Comparing Orbits of Pulsar and Its Companion to our Solar System. CREDIT: Bill Saxton, NRAO/AUI/NSF Click on image for full caption information and available graphics. "Our ideas about how the fastest-spinning pulsars are produced do not predict either the kind of orbit or the type of companion star this one has," said David Champion of the Australia Telescope National Facility. "We have to come up with some new scenarios to explain this weird pair," he added. Astronomers first detected the pulsar, called J1903+0327, as part of a long-term survey using the National Science Foundation's Arecibo radio telescope in Puerto Rico. They made the discovery in 2006 doing data analysis at McGill University, where Champion worked at the time. They followed up the discovery with detailed studies using the Arecibo telescope, the NSF's Robert C. Byrd Green Bank Telescope (GBT) in West Virginia, the Westerbork radio telescope in the Netherlands, and the Gemini North optical telescope in Hawaii. The pulsar, a city-sized superdense stellar corpse left over after a massive star exploded as a supernova, is spinning on its axis 465 times every second. Nearly 21,000 light-years from Earth, it is in a highly-elongated orbit that takes it around its companion star once every 95 days. An infrared image made with the Gemini North telescope in Hawaii shows a Sun-like star at the pulsar's position. If this is an orbital companion to the pulsar, it is unlike any companions of other rapidly rotating pulsars. The pulsar, a neutron star, also is unusually massive for its type. "This combination of properties is unprecedented. Not only does it require us to figure out how this system was produced, but the large mass may help us understand how matter behaves at extremely

  19. A Curious Pair of Galaxies

    NASA Astrophysics Data System (ADS)

    2009-03-01

    The ESO Very Large Telescope has taken the best image ever of a strange and chaotic duo of interwoven galaxies. The images also contain some surprises -- interlopers both far and near. ESO PR Photo 11a/09 A Curious Pair of Galaxies ESO PR Video 11a/09 Arp 261 zoom in ESO PR Video 11b/09 Pan over Arp 261 Sometimes objects in the sky that appear strange, or different from normal, have a story to tell and prove scientifically very rewarding. This was the idea behind Halton Arp's catalogue of Peculiar Galaxies that appeared in the 1960s. One of the oddballs listed there is Arp 261, which has now been imaged in more detail than ever before using the FORS2 instrument on ESO's Very Large Telescope. The image proves to contain several surprises. Arp 261 lies about 70 million light-years distant in the constellation of Libra, the Scales. Its chaotic and very unusual structure is created by the interaction of two galaxies that are engaged in a slow motion, but highly disruptive close encounter. Although individual stars are very unlikely to collide in such an event, the huge clouds of gas and dust certainly do crash into each other at high speed, leading to the formation of bright new clusters of very hot stars that are clearly seen in the picture. The paths of the existing stars in the galaxies are also dramatically disrupted, creating the faint swirls extending to the upper left and lower right of the image. Both interacting galaxies were probably dwarfs not unlike the Magellanic Clouds orbiting our own galaxy. The images used to create this picture were not actually taken to study the interacting galaxies at all, but to investigate the properties of the inconspicuous object just to the right of the brightest part of Arp 261 and close to the centre of the image. This is an unusual exploding star, called SN 1995N, that is thought to be the result of the final collapse of a massive star at the end of its life, a so-called core collapse supernova. SN 1995N is unusual because

  20. Pair creation in heavy ion channeling

    NASA Astrophysics Data System (ADS)

    Belov, N. A.; Harman, Z.

    2016-04-01

    Heavy ions channeled through crystals with multi-GeV kinetic energies can create electron-positron pairs. In the framework of the ion, the energy of virtual photons arising from the periodic crystal potential may exceed the threshold 2mec2. The repeated periodic collisions with the crystal ions yield high pair production rates. When the virtual photon frequency matches a nuclear transition in the ion, the production rate can be resonantly increased. In this two-step excitation-pair conversion scheme, the excitation rates are coherently enhanced, and scale approximately quadratically with the number of crystal sites along the channel.

  1. Pairing effects on neutrino transport in low-density stellar matter

    NASA Astrophysics Data System (ADS)

    Burrello, S.; Colonna, M.; Matera, F.

    2016-07-01

    We investigate the impact of pairing correlations on neutrino transport in stellar matter. Our analysis is extended to nuclear matter conditions where large density fluctuations may develop, associated with the onset of the liquid-vapor phase transition, and where clustering phenomena occur. Within a thermodynamical treatment, we show that at moderate temperatures, where pairing effects are still active, the scattering of neutrinos in the nuclear medium is significantly affected by pairing correlations, which increase the neutrino trapping, thus modifying the cooling mechanism, by neutrino emission, of protoneutron stars.

  2. Radical-Ion-Pair Spin Decoherence and the Quantum Efficiency of Photosynthetic Charge Separation

    NASA Astrophysics Data System (ADS)

    Kominis, Iannis; Dellis, A. T.

    2014-03-01

    We have pioneered the fundamental quantum dynamics of radical-ion-pair reactions, elucidating the basic spin-decoherence mechanism pertaining to these biochemical reactions. Radical-ion pair reactions appear in the avian magnetic compass, but more importantly, they participate in the cascade of electron-transfer reactions taking place in photosynthetic reaction centers. We will here present new insights on how the fundamental quantum dynamics of radical-ion pair reactions affect the quantum efficiency of charge separation in photosynthetic reaction centers.

  3. Flutter of pairs of aerodynamically interfering delta wings.

    NASA Technical Reports Server (NTRS)

    Chipman, R. R.; Rauch, F. J.; Hess, R. W.

    1973-01-01

    To examine the effect on flutter of the aerodynamic interference between pairs of closely spaced delta wings, several structurally uncoupled 1/80th-scale models were studied by experiment and analysis. Flutter test boundaries obtained in NASA Langley's 26-in. transonic blowdown wind tunnel were compared with subsonic analytical results generated using the doublet lattice method. Trends for several combinations of vertical and longitudinal wing separation were determined, showing flutter speed significantly affected in the closely spaced configurations. A new flutter mechanism coupling one wing's first bending mode with the other wing's first torsion mode was predicted and observed.

  4. Underwater acoustic source localization using closely spaced hydrophone pairs

    NASA Astrophysics Data System (ADS)

    Sim, Min Seop; Choi, Bok-Kyoung; Kim, Byoung-Nam; Lee, Kyun Kyung

    2016-07-01

    Underwater sound source position is determined using a line array. However, performance degradation occurs owing to a multipath environment, which generates incoherent signals. In this paper, a hydrophone array is proposed for underwater source position estimation robust to a multipath environment. The array is composed of three pairs of sensors placed on the same line. The source position is estimated by performing generalized cross-correlation (GCC). The proposed system is not affected by a multipath time delay because of the close distance between closely spaced sensors. The validity of the array is confirmed by simulation using acoustic signals synthesized by eigenrays.

  5. Pair-production in inhomogeneous electric fields

    SciTech Connect

    Xue Shesheng

    2008-01-03

    This is a preliminary study on the rate of electron-positron pair production in spatially inhomogeneous electric fields. We study the rate in the Sauter field and compare it to the rate in the homogeneous field.

  6. Chromosomally-retained RNA mediates homologous pairing.

    PubMed

    Ding, Da-Qiao; Haraguchi, Tokuko; Hiraoka, Yasushi

    2012-01-01

    Pairing and recombination of homologous chromosomes are essential for ensuring correct segregation of chromosomes in meiosis. In S. pombe, chromosomes are first bundled at the telomeres (forming a telomere bouquet) and then aligned by oscillatory movement of the elongated "horsetail" nucleus. Telomere clustering and subsequent chromosome alignment promote pairing of homologous chromosomes. However, this telomere-bundled alignment of chromosomes cannot be responsible for the specificity of chromosome pairing. Thus, there must be some mechanism to facilitate recognition of homologous partners after telomere clustering. Recent studies in S. pombe have shown that RNA transcripts retained on the chromosome, or RNA bodies, may play a role in recognition of homologous chromosomes for pairing. Acting as fiducial markers of homologous loci they would abrogate the need for direct DNA sequence homology searching. PMID:23117617

  7. Atomic Collisions and free Lepton Pair Production

    SciTech Connect

    Gueclue, M.C.; Yilmaz, M.

    2005-10-26

    In this work, we have calculated the total cross sections of electron-positron pair production for the collisions of fully stripped gold ions for various energies. We have also compared our calculation with other methods.

  8. Alloy solution hardening with solute pairs

    DOEpatents

    Mitchell, John W.

    1976-08-24

    Solution hardened alloys are formed by using at least two solutes which form associated solute pairs in the solvent metal lattice. Copper containing equal atomic percentages of aluminum and palladium is an example.

  9. 90 Seconds of Discovery: Frustrated Lewis Pairs

    SciTech Connect

    Kathmann, Shawn; Schenter, Greg; Autrey, Tom

    2014-02-14

    Hydrogen activating catalysts play an important role in producing valuable chemicals, such as biofuels and ammonia. As a part of efforts to develop the next generation of these catalysts, PNNL researchers have found potential in Frustrated Lewis Pairs.

  10. A Pair Polarimeter for High Energy Photons

    NASA Astrophysics Data System (ADS)

    Tedeschi, David; Wojtsekhowski, B.; Abbott, D.; Vlahovic, B.; Hotta, T.; Kohri, H.; Matsumura, T.; Mibe, T.; Nakano, T.; Yurita, T.; Zegers, R.; Khandaker, M.; Feldman, G.; O'Rielly, G. V.; Wood, M.; Asai, G.; Rudge, A.; Weilhammer, P.

    2001-10-01

    The physics program at the Thomas Jefferson National Accelerator Facility includes fundamental experiments with polarized photon beams in the GeV energy range. To measure the degree of photon polarization, a photon polarimeter based on the detection of e^+e^- pairs has been developed for use in Hall B and was recently tested at the LEPS facility at SPring-8 in Japan. The use of silicon micro-strip detectors allows for the first time the measurement of the angle correlation in electron-positron pair production by high energy photons incident on an amorphous converter. Theoretical calculations of the pair production process show an asymmetry σ_allel/σ_⊥ ~ 1.7 in a wide range of photon energies. Experimental results from the measurement of the pair asymmetry using 2 GeV photons from the SPring-8 facility will be presented.

  11. 90 Seconds of Discovery: Frustrated Lewis Pairs

    ScienceCinema

    Kathmann, Shawn; Schenter, Greg; Autrey, Tom

    2014-07-21

    Hydrogen activating catalysts play an important role in producing valuable chemicals, such as biofuels and ammonia. As a part of efforts to develop the next generation of these catalysts, PNNL researchers have found potential in Frustrated Lewis Pairs.

  12. Spectra from pair-equilibrium plasmas

    NASA Technical Reports Server (NTRS)

    Zdziarski, A. A.

    1984-01-01

    A numerical model of relativistic nonmagnetized plasma with uniform temperature and electron density distributions is considered, and spectra from plasma in pair equilibrium are studied. A range of dimensionless temperature (T) greater than about 0.2 is considered. The spectra from low pair density plasmas in pair equilibrium vary from un-Comptonized bremsstrahlung spectra at Thomson cross section tau(N) much less than one to Comptonized bremsstrahlung spectra with tau(N) over one. For high pair density plasmas the spectra are flat for T greater than about one, and have broad intensity peaks at energy roughly equal to 3T for T less than one. In the latter region the total luminosity is approximately twice the annihilation luminosity. All spectra are flat in the X-ray region, in contradiction to observed AGN spectra. For dimensionless luminosity greater than about 100, the cooling time becomes shorter than the Thomson time.

  13. Robustness of quantum critical pairing against disorder

    NASA Astrophysics Data System (ADS)

    Kang, Jian; Fernandes, Rafael M.

    2016-06-01

    The remarkable robustness of high-temperature superconductors against disorder remains a controversial obstacle towards the elucidation of their pairing state. Indeed, experiments report a weak suppression rate of the transition temperature Tc with disorder, significantly smaller than the universal value predicted by extensions of the conventional theory of dirty superconductors. However, in many high-Tc compounds, superconductivity appears near a putative magnetic quantum critical point, suggesting that quantum fluctuations, which suppress coherent electronic spectral weight, may also promote unconventional pairing. Here we investigate theoretically the impact of disorder on such a quantum critical pairing state, considering the coupling of impurities both to the low-energy electronic states and to the pairing interaction itself. We find a significant reduction in the suppression rate of Tc with disorder near the magnetic quantum critical point, shedding new light on the nature of unconventional superconductivity in correlated materials.

  14. Non stationary pair model in blazar

    NASA Astrophysics Data System (ADS)

    Marcowith, Alexandre; Henri, Gilles; Renaud, Nicolas

    2001-09-01

    This article shortly present an improved version of pair models for X and gamma-ray emission from blazar jets. The radiations are generated through external and synchrotron Inverse Compton mechanisms in the vicinity of a super-massive black hole by an ultra-relativistic electron-positron pair plasma pervading a non-relativistic electron-proton jet (two-flow model). Non stationary solutions are found by solving simultaneously pair creation/annihilation, soft photon absorption and particle acceleration processes along the jet. The power supply necessary to re-accelerate particles is not treated in a self-consistent procedure but parametrised. Pair creation opacity effects can lead to interesting variability effects depending on the X-ray emission regimes. Multi-wavelength observations by INTEGRAL will provide tests for the model, and also for the matter content and variability mechanisms in compact sources.

  15. Ultrabright source of entangled photon pairs.

    PubMed

    Dousse, Adrien; Suffczyński, Jan; Beveratos, Alexios; Krebs, Olivier; Lemaître, Aristide; Sagnes, Isabelle; Bloch, Jacqueline; Voisin, Paul; Senellart, Pascale

    2010-07-01

    A source of triggered entangled photon pairs is a key component in quantum information science; it is needed to implement functions such as linear quantum computation, entanglement swapping and quantum teleportation. Generation of polarization entangled photon pairs can be obtained through parametric conversion in nonlinear optical media or by making use of the radiative decay of two electron-hole pairs trapped in a semiconductor quantum dot. Today, these sources operate at a very low rate, below 0.01 photon pairs per excitation pulse, which strongly limits their applications. For systems based on parametric conversion, this low rate is intrinsically due to the Poissonian statistics of the source. Conversely, a quantum dot can emit a single pair of entangled photons with a probability near unity but suffers from a naturally very low extraction efficiency. Here we show that this drawback can be overcome by coupling an optical cavity in the form of a 'photonic molecule' to a single quantum dot. Two coupled identical pillars-the photonic molecule-were etched in a semiconductor planar microcavity, using an optical lithography method that ensures a deterministic coupling to the biexciton and exciton energy states of a pre-selected quantum dot. The Purcell effect ensures that most entangled photon pairs are emitted into two cavity modes, while improving the indistinguishability of the two optical recombination paths. A polarization entangled photon pair rate of 0.12 per excitation pulse (with a concurrence of 0.34) is collected in the first lens. Our results open the way towards the fabrication of solid state triggered sources of entangled photon pairs, with an overall (creation and collection) efficiency of 80%. PMID:20613838

  16. Particle-number-projected thermal pairing

    SciTech Connect

    Nguyen Dinh Dang

    2007-12-15

    Particle-number projection is applied to the modified BCS (MBCS) theory. The resulting particle-number-projected MBCS theory, taking into account the effects due to fluctuations of particle and quasiparticle numbers at finite temperature, is tested within the exactly solvable multilevel model for pairing as well as the realistic {sup 120}Sn nucleus. The signature of the pseudogap in the crossover region above the critical temperature of superfluid-normal phase transition is discussed in terms of the pairing spectral function.

  17. Moral Appraisals Affect Doing/Allowing Judgments

    ERIC Educational Resources Information Center

    Cushman, Fiery; Knobe, Joshua; Sinnott-Armstrong, Walter

    2008-01-01

    An extensive body of research suggests that the distinction between doing and allowing plays a critical role in shaping moral appraisals. Here, we report evidence from a pair of experiments suggesting that the converse is also true: moral appraisals affect doing/allowing judgments. Specifically, morally bad behavior is more likely to be construed…

  18. Seniority zero pair coupled cluster doubles theory

    SciTech Connect

    Stein, Tamar; Henderson, Thomas M.; Scuseria, Gustavo E.

    2014-06-07

    Coupled cluster theory with single and double excitations accurately describes weak electron correlation but is known to fail in cases of strong static correlation. Fascinatingly, however, pair coupled cluster doubles (p-CCD), a simplified version of the theory limited to pair excitations that preserve the seniority of the reference determinant (i.e., the number of unpaired electrons), has mean field computational cost and is an excellent approximation to the full configuration interaction (FCI) of the paired space provided that the orbital basis defining the pairing scheme is adequately optimized. In previous work, we have shown that optimization of the pairing scheme in the seniority zero FCI leads to a very accurate description of static correlation. The same conclusion extends to p-CCD if the orbitals are optimized to make the p-CCD energy stationary. We here demonstrate these results with numerous examples. We also explore the contributions of different seniority sectors to the coupled cluster doubles (CCD) correlation energy using different orbital bases. We consider both Hartree-Fock and Brueckner orbitals, and the role of orbital localization. We show how one can pair the orbitals so that the role of the Brueckner orbitals at the CCD level is retained at the p-CCD level. Moreover, we explore ways of extending CCD to accurately describe strongly correlated systems.

  19. Paired inhibitory and activating receptor signals.

    PubMed

    Taylor, L S; Paul, S P; McVicar, D W

    2000-01-01

    The immunological literature has become inundated with reports regarding paired inhibitory receptors. Paired inhibitory receptor systems are highly conserved families that contain receptors involved in either cellular inhibition or activation. In most cases the paired putative biochemical antagonists are co-expressed on a given cell and thought to bind similar, if not identical, ligands making their biological role difficult to understand. Examples of these systems include immunoglobulin (Ig)-like receptors (Killer Ig Receptors, Immunoglobulin-like Transcripts/Leukocyte Ig-like Receptors/Monocyte Macrophage Ig Receptors, and Paired Ig-like Receptors), and type II lectin-like receptor systems (NKG2 and Ly49). General characteristics of these inhibitory receptors include a cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM). The ITIM is phosphorylated upon engagement and recruits protein tyrosine phosphatases that dephosphorylate cellular substrates that would otherwise mediate activation. In contrast, the activating receptors of these pairs use charged residues within their transmembrane domains to associate with various signal transduction chains including the gamma chain of the receptor for the Fc portion of IgE, DAP12 or DAP10. Once phosphorylated, these chains direct the signal transduction cascade resulting in cellular activation. Here we review the signaling of several paired systems and present the current models for their signal transduction cascades. PMID:11258418

  20. Migration of helium-pair in metals

    NASA Astrophysics Data System (ADS)

    Cao, J. L.; Geng, W. T.

    2016-09-01

    We have carried out a first-principles density functional theory investigation into the migration of both a single interstitial He and an interstitial He-pair in Fe, Mo, W, Cu, Pd, and Pt. We find the migration trajectories and barriers are determined predominantly by low-energy He-pair configurations which depend mainly on the energy state of a single He in different interstices. The migration barrier for a He-pair in bcc metals is always slightly higher than for a single He. Configurations of a He-pair in fcc metals are very complicated, due to the existence of interstitial sites with nearly identical energy for a single He. The migration barrier for a He-pair is slightly lower than (in Cu), or similar to (in Pd and Pt) a single He. The collective migrations of a He-pair are ensured by strong Hesbnd He interactions with strength-versus-distance forms resembling chemical bonds and can be described with Morse potentials.

  1. Pairing interaction effects in exciton level densities

    SciTech Connect

    Fu, C.Y.

    1989-01-01

    Recent progress in pairing corrections for exciton state-density formulas used in pre-compound nuclear reaction theories is reviewed. These correction factors are, strictly speaking, dependent on the nuclear excitation energy U and the exciton number n. A simple formula for (U,n)-dependent pairing corrections has been derived, based on the BCS pairing equations for constant single-particle spacing, for the exciton state-density formula for one kind of Fermion. It has been shown that the constant-pairing-energy correction used in standard state-density formulas, such U{sub 0} in Gilbert and Cameron, is a limiting case of the general (U,n)-dependent results. Spin cutoff factors with pairing effects were also obtained using the same theory and parameterized into an explicit (U,n)-dependent function, thereby defining a simple exciton level-density formula for applications in quantum mechanical precompound theories. Preliminary results from extending such simple pairing-interaction representations to level-density formulas for two kinds of Fermions are summarized. The results show that the ratios in the exciton level densities in the one-Fermion and two-Fermion approaches vary with both U and n, thus likely leading to differences in calculated compound to precompound ratios. However, the differences in the spin cutoff factors in the two cases are found to be rather small. 12 refs., 3 figs.

  2. Spectral similarity of unbound asteroid pairs

    NASA Astrophysics Data System (ADS)

    Wolters, Stephen D.; Weissman, Paul R.; Christou, Apostolis; Duddy, Samuel R.; Lowry, Stephen C.

    2014-04-01

    Infrared (IR) spectroscopy between 0.8 and 2.5 μ has been obtained for both components of three unbound asteroid pairs, using the NASA Infrared Telescope Facility with the SpeX instrument. Pair primary (2110) Moore-Sitterly is classified as an S-type following the Bus-DeMeo taxonomy; the classification for secondary (44612) 1999 RP27 is ambiguous: S/Sq/Q/K/L-type. Primary (10484) Hecht and secondary (44645) 1999 RC118 are classified as V-types. IR spectra for Moore-Sitterly and Hecht are each linked with available visual photometry. The classifications for primary (88604) 2001 QH293 and (60546) 2000 EE85 are ambiguous: S/Sq/Q/K/L-type. Subtle spectral differences between them suggest that the primary may have more weathered material on its surface. Dynamical integrations have constrained the ages of formation: 2110-44612 > 782 kyr; 10484-44645 = 348 (+823,-225) kyr; 88604-60546 = 925 (+842,-754) kyr. The spectral similarity of seven complete pairs is ranked in comparison with nearby background asteroids. Two pairs, 17198-229056 and 19289-278067, have significantly different spectra between the components, compared to the similarity of spectra in the background population. The other pairs are closer than typical, supporting an interpretation of each pair's formation from a common parent body.

  3. Multipair approach to pairing in nuclei

    NASA Astrophysics Data System (ADS)

    Sambataro, M.

    2012-06-01

    The ground state of a general pairing Hamiltonian for a finite nuclear system is constructed as a product of collective, real, distinct pairs. These are determined sequentially via an iterative variational procedure that resorts to diagonalizations of the Hamiltonian in restricted model spaces. Different applications of the method are provided that include comparisons with exact and projected BCS results. The quantities that are examined are correlation energies, occupation numbers, and pair transfer matrix elements. In a first application within the picket-fence model, the method is seen to generate the exact ground state for pairing strengths confined in a given range. Further applications of the method concern pairing in spherically symmetric mean fields and include simple exactly solvable models as well as some realistic calculations for middle-shell Sn isotopes. In the latter applications, two different ways of defining the pairs are examined: either with J=0 or with no well defined angular momentum. The second choice is revealed to be more effective, leading, under some circumstances, to solutions that are basically exact.

  4. Fundamental aspects of recoupled pair bonds. I. Recoupled pair bonds in carbon and sulfur monofluoride

    SciTech Connect

    Dunning, Thom H. Xu, Lu T.; Takeshita, Tyler Y.

    2015-01-21

    The number of singly occupied orbitals in the ground-state atomic configuration of an element defines its nominal valence. For carbon and sulfur, with two singly occupied orbitals in their {sup 3}P ground states, the nominal valence is two. However, in both cases, it is possible to form more bonds than indicated by the nominal valence—up to four bonds for carbon and six bonds for sulfur. In carbon, the electrons in the 2s lone pair can participate in bonding, and in sulfur the electrons in both the 3p and 3s lone pairs can participate. Carbon 2s and sulfur 3p recoupled pair bonds are the basis for the tetravalence of carbon and sulfur, and 3s recoupled pair bonds enable sulfur to be hexavalent. In this paper, we report generalized valence bond as well as more accurate calculations on the a{sup 4}Σ{sup −} states of CF and SF, which are archetypal examples of molecules that possess recoupled pair bonds. These calculations provide insights into the fundamental nature of recoupled pair bonds and illustrate the key differences between recoupled pair bonds formed with the 2s lone pair of carbon, as a representative of the early p-block elements, and recoupled pair bonds formed with the 3p lone pair of sulfur, as a representative of the late p-block elements.

  5. Detection of Majorana Kramers Pairs Using a Quantum Point Contact.

    PubMed

    Li, Jian; Pan, Wei; Bernevig, B Andrei; Lutchyn, Roman M

    2016-07-22

    We propose a setup that integrates a quantum point contact (QPC) and a Josephson junction on a quantum spin Hall sample, experimentally realizable in InAs/GaSb quantum wells. The confinement due to both the QPC and the superconductor results in a Kramers pair of Majorana zero-energy bound states when the superconducting phases in the two arms differ by an odd multiple of π across the Josephson junction. We investigate the detection of these Majorana pairs with the integrated QPC, and find a robust switching from normal to Andreev scattering across the edges due to the presence of Majorana Kramers pairs. Such a switching of the current represents a qualitative signature where multiterminal differential conductances oscillate with alternating signs when the external magnetic field is tuned. We show that this qualitative signature is also present in current cross-correlations. Thus, the change of the backscattering current nature affects both conductance and shot noise, the measurement of which offers a significant advantage over quantitative signatures such as conductance quantization in realistic measurements. PMID:27494493

  6. Tauopathy with paired helical filaments in an aged chimpanzee.

    PubMed

    Rosen, Rebecca F; Farberg, Aaron S; Gearing, Marla; Dooyema, Jeromy; Long, Patrick M; Anderson, Daniel C; Davis-Turak, Jeremy; Coppola, Giovanni; Geschwind, Daniel H; Paré, Jean-Francois; Duong, Timothy Q; Hopkins, William D; Preuss, Todd M; Walker, Lary C

    2008-07-20

    An enigmatic feature of age-related neurodegenerative diseases is that they seldom, if ever, are fully manifested in nonhuman species under natural conditions. The neurodegenerative tauopathies are typified by the intracellular aggregation of hyperphosphorylated microtubule-associated protein tau (MAPT) and the dysfunction and death of affected neurons. We document the first case of tauopathy with paired helical filaments in an aged chimpanzee (Pan troglodytes). Pathologic forms of tau in neuronal somata, neuropil threads, and plaque-like clusters of neurites were histologically identified throughout the neocortex and, to a lesser degree, in allocortical and subcortical structures. Ultrastructurally, the neurofibrillary tangles consisted of tau-immunoreactive paired helical filaments with a diameter and helical periodicity indistinguishable from those seen in Alzheimer's disease. A moderate degree of Abeta deposition was present in the cerebral vasculature and, less frequently, in senile plaques. Sequencing of the exons and flanking intronic regions in the genomic MAPT locus disclosed no mutations that are associated with the known human hereditary tauopathies, nor any polymorphisms of obvious functional significance. Although the lesion profile in this chimpanzee differed somewhat from that in Alzheimer's disease, the copresence of paired helical filaments and Abeta-amyloidosis indicates that the molecular mechanisms for the pathogenesis of the two canonical Alzheimer lesions--neurofibrillary tangles and senile plaques--are present in aged chimpanzees. PMID:18481275

  7. Detection of Majorana Kramers Pairs Using a Quantum Point Contact

    NASA Astrophysics Data System (ADS)

    Li, Jian; Pan, Wei; Bernevig, B. Andrei; Lutchyn, Roman M.

    2016-07-01

    We propose a setup that integrates a quantum point contact (QPC) and a Josephson junction on a quantum spin Hall sample, experimentally realizable in InAs/GaSb quantum wells. The confinement due to both the QPC and the superconductor results in a Kramers pair of Majorana zero-energy bound states when the superconducting phases in the two arms differ by an odd multiple of π across the Josephson junction. We investigate the detection of these Majorana pairs with the integrated QPC, and find a robust switching from normal to Andreev scattering across the edges due to the presence of Majorana Kramers pairs. Such a switching of the current represents a qualitative signature where multiterminal differential conductances oscillate with alternating signs when the external magnetic field is tuned. We show that this qualitative signature is also present in current cross-correlations. Thus, the change of the backscattering current nature affects both conductance and shot noise, the measurement of which offers a significant advantage over quantitative signatures such as conductance quantization in realistic measurements.

  8. Experiments on a Cooper pair insulator

    NASA Astrophysics Data System (ADS)

    Nguyen, Hung Q.

    At temperatures below 1K, nm thick a-Bi/Sb films, patterned with a nanohoneycomb array of holes, exhibit a novel electronic state consisting of localized Cooper pairs[1]. The Superconductor Insulator Transition (SIT), a phenomenon where the ground state of electrons is tuned from a superconducting to an insulating state, on this patterned homogeneous system shows a clear bosonic nature with activated transport on the insulating side. To date, this homogeneous system is the only one that shows clear evidence for the localization of Cooper pairs. Experiments are described that were performed to further characterize the properties of the localized Cooper pair state and its superconductor to insulator transitions. We show that: (i) The shape of the magnetoresistance (MR) oscillations, which indicate the presence of Cooper pairs in these multiply connected systems, depends on the geometry of the underlying substrates, but not on parameters like the temperature or thickness of the films. The magnetic field tuned SITs of films that are just thick enough to superconduct at zero magnetic field exhibit a common critical sheet resistance separating the superconducting and insulating phases in the range of 3.5 to 5kO. We also report a new type of SIT, an incommensurability driven SIT, which occurs due to the interplay of magnetic field and disorder in the arrangement of the honeycomb array of holes. (ii) The Cooper pair insulator state exhibits a giant positive MR, which peaks at a field estimated to be sufficient to break the pairs. The electrical transport on the low field side of the peak is activated. At the highest fields, it resembles G ˜ log(T), which is consistent with the behavior expected for weakly localized electrons rather than strongly localized Cooper pairs. We discuss this MR peak, compare it to that observed in other amorphous systems and propose a zero temperature phase diagram for these films.

  9. Pairing in a dry Fermi sea

    PubMed Central

    Maier, T. A; Staar, P.; Mishra, V.; Chatterjee, U.; Campuzano, J. C.; Scalapino, D. J.

    2016-01-01

    In the traditional Bardeen–Cooper–Schrieffer theory of superconductivity, the amplitude for the propagation of a pair of electrons with momentum k and −k has a log singularity as the temperature decreases. This so-called Cooper instability arises from the presence of an electron Fermi sea. It means that an attractive interaction, no matter how weak, will eventually lead to a pairing instability. However, in the pseudogap regime of the cuprate superconductors, where parts of the Fermi surface are destroyed, this log singularity is suppressed, raising the question of how pairing occurs in the absence of a Fermi sea. Here we report Hubbard model numerical results and the analysis of angular-resolved photoemission experiments on a cuprate superconductor. In contrast to the traditional theory, we find that in the pseudogap regime the pairing instability arises from an increase in the strength of the spin–fluctuation pairing interaction as the temperature decreases rather than the Cooper log instability. PMID:27312569

  10. Terminal Area Procedures for Paired Runways

    NASA Technical Reports Server (NTRS)

    Lozito, Sandy

    2011-01-01

    Parallel Runway operations have been found to increase capacity within the National Airspace (NAS) however, poor visibility conditions reduce this capacity [1]. Much research has been conducted to examine the concepts and procedures related to parallel runways however, there has been no investigation of the procedures associated with the strategic and tactical pairing of aircraft for these operations. This study developed and examined the pilot and controller procedures and information requirements for creating aircraft pairs for parallel runway operations. The goal was to achieve aircraft pairing with a temporal separation of 15s(+/- 10s error) at a coupling point that is about 12 nmi from the runway threshold. Two variables were explored for the pilot participants: Two levels of flight deck automation (current-day flight deck automation, and a prototype future automation) as well as two flight deck displays that assisted in pilot conformance monitoring. The controllers were also provided with automation to help create and maintain aircraft pairs. Data showed that the operations in this study were found to be acceptable and safe. Workload when using the pairing procedures and tools was generally low for both controllers and pilots, and situation awareness (SA) was typically moderate to high. There were some differences based upon the display and automation conditions for the pilots. Future research should consider the refinement of the concepts and tools for pilot and controller displays and automation for parallel runway concepts.

  11. Radical-pair based avian magnetoreception

    NASA Astrophysics Data System (ADS)

    Procopio, Maria; Ritz, Thorsten

    2014-03-01

    Behavioural experiments suggest that migratory birds possess a magnetic compass sensor able to detect the direction of the geomagnetic. One hypothesis for the basis of this remarkable sensory ability is that the coherent quantum spin dynamics of photoinduced radical pair reactions transduces directional magnetic information from the geomagnetic field into changes of reaction yields, possibly involving the photoreceptor cryptochrome in the birds retina. The suggested radical-pair based avian magnetoreception has attracted attention in the field of quantum biology as an example of a biological sensor which might exploit quantum coherences for its biological function. Investigations on such a spin-based sensor have focussed on uncovering the design features for the design of a biomimetic magnetic field sensor. We study the effects of slow fluctuations in the nuclear spin environment on the directional signal. We quantitatively evaluate the robustness of signals under fluctuations on a timescale longer than the lifetime of a radical pair, utilizing two models of radical pairs. Our results suggest design principles for building a radical-pair based compass sensor that is both robust and highly directional sensitive.

  12. Pair creation of black holes during inflation

    NASA Astrophysics Data System (ADS)

    Bousso, Raphael; Hawking, Stephen W.

    1996-11-01

    Black holes came into existence together with the universe through the quantum process of pair creation in the inflationary era. We present the instantons responsible for this process and calculate the pair creation rate from the no boundary proposal for the wave function of the universe. We find that this proposal leads to physically sensible results, which fit in with other descriptions of pair creation, while the tunneling proposal makes unphysical predictions. We then describe how the pair-created black holes evolve during inflation. In the classical solution, they grow with the horizon scale during the slow roll down of the inflaton field; this is shown to correspond to the flux of field energy across the horizon according to the first law of black hole mechanics. When quantum effects are taken into account, however, it is found that most black holes evaporate before the end of inflation. Finally, we consider the pair creation of magnetically charged black holes, which cannot evaporate. In standard Einstein-Maxwell theory we find that their number in the presently observable universe is exponentially small. We speculate how this conclusion may change if dilatonic theories are applied.

  13. On the analysis of phylogenetically paired designs

    PubMed Central

    Funk, Jennifer L; Rakovski, Cyril S; Macpherson, J Michael

    2015-01-01

    As phylogenetically controlled experimental designs become increasingly common in ecology, the need arises for a standardized statistical treatment of these datasets. Phylogenetically paired designs circumvent the need for resolved phylogenies and have been used to compare species groups, particularly in the areas of invasion biology and adaptation. Despite the widespread use of this approach, the statistical analysis of paired designs has not been critically evaluated. We propose a mixed model approach that includes random effects for pair and species. These random effects introduce a “two-layer” compound symmetry variance structure that captures both the correlations between observations on related species within a pair as well as the correlations between the repeated measurements within species. We conducted a simulation study to assess the effect of model misspecification on Type I and II error rates. We also provide an illustrative example with data containing taxonomically similar species and several outcome variables of interest. We found that a mixed model with species and pair as random effects performed better in these phylogenetically explicit simulations than two commonly used reference models (no or single random effect) by optimizing Type I error rates and power. The proposed mixed model produces acceptable Type I and II error rates despite the absence of a phylogenetic tree. This design can be generalized to a variety of datasets to analyze repeated measurements in clusters of related subjects/species. PMID:25750719

  14. Probing the tides in interacting galaxy pairs

    NASA Technical Reports Server (NTRS)

    Borne, Kirk D.

    1990-01-01

    Detailed spectroscopic and imaging observations of colliding elliptical galaxies revealed unmistakable diagnostic signatures of the tidal interactions. It is possible to compare both the distorted luminosity distributions and the disturbed internal rotation profiles with numerical simulations in order to model the strength of the tidal gravitational field acting within a given pair of galaxies. Using the best-fit numerical model, one can then measure directly the mass of a specific interacting binary system. This technique applies to individual pairs and therefore complements the classical methods of measuring the masses of galaxy pairs in well-defined statistical samples. The 'personalized' modeling of galaxy pairs also permits the derivation of each binary's orbit, spatial orientation, and interaction timescale. Similarly, one can probe the tides in less-detailed observations of disturbed galaxies in order to estimate some of the physical parameters for larger samples of interacting galaxy pairs. These parameters are useful inputs to the more universal problems of (1) the galaxy merger rate, (2) the strength and duration of the driving forces behind tidally stimulated phenomena (e.g., starbursts and maybe quasi steller objects), and (3) the identification of long-lived signatures of interaction/merger events.

  15. Pairing in a dry Fermi sea

    DOE PAGESBeta

    Maier, Thomas A.; Staar, Peter; Mishra, V.; Chatterjee, Utpal; Campuzano, J. C.; Scalapino, Douglas J.

    2016-06-17

    In the traditional Bardeen–Cooper–Schrieffer theory of superconductivity, the amplitude for the propagation of a pair of electrons with momentum k and -k has a log singularity as the temperature decreases. This so-called Cooper instability arises from the presence of an electron Fermi sea. It means that an attractive interaction, no matter how weak, will eventually lead to a pairing instability. However, in the pseudogap regime of the cuprate superconductors, where parts of the Fermi surface are destroyed, this log singularity is suppressed, raising the question of how pairing occurs in the absence of a Fermi sea. In this paper, wemore » report Hubbard model numerical results and the analysis of angular-resolved photoemission experiments on a cuprate superconductor. Finally, in contrast to the traditional theory, we find that in the pseudogap regime the pairing instability arises from an increase in the strength of the spin–fluctuation pairing interaction as the temperature decreases rather than the Cooper log instability.« less

  16. Electron pair emission from surfaces: Intensity relations

    NASA Astrophysics Data System (ADS)

    Schumann, F. O.; Aliaev, Y.; Kostanovskiy, I.; Di Filippo, G.; Wei, Z.; Kirschner, J.

    2016-06-01

    The emission of an electron pair upon single-photon absorption requires a finite electron-electron interaction. Therefore, double photoemission is a particularly sensitive tool to study the electron correlation in matter. This is supported by a recent theoretical work which predicts that the pair intensity is a direct reflection of the correlation strength. In order to explore the validity of this statement, we performed a study on a variety of materials. Among them are noble metals, transition metals, and insulators. The latter include transition metal oxides such as CoO and NiO which are also termed highly correlated. We find an increased pair emission rate of NiO and CoO compared to the metals which reach a factor of 10. We also discovered that an increase of the coincidence intensity is accompanied by an increase in the singles count rate. This demonstrates that the electron pair emission is an efficient process at surfaces contributing up to 15 % to the single-electron emission in double photoemission. We performed also electron pair emission studies upon primary electron impact and find similar intensity relations.

  17. Cooper-pair splitter: towards an efficient source of spin-entangled EPR pairs

    NASA Astrophysics Data System (ADS)

    Schonenberger, Christian

    2011-03-01

    In quantum mechanics the properties of two and more particles can be entangled. In basic science pairs of entangled particles, so called Einstein-Podolsky-Rosen (EPR) pairs, play a special role as toy objects for fundamental studies. They provide such things as ``spooky interaction at distance,'' but they also enable secure encoding and teleportation and are thus important for applications in quantum information technology. Whereas EPR pairs of photons can be generated by parametric down conversion (PDC) in a crystal, a similar source for EPR pairs of electrons does not exists yet. In several theory papers, it has been suggested to use a superconductor for this purpose. The superconducting ground state is formed by a condensate of Cooper-pairs which are electron pairs in a spin-singlet state. Since there are many Cooper pairs in a metallic superconductor like Al, the main tasks are to extract Cooper pairs one by one and to split them into different arms. A controlled and efficient splitting is possible if one makes use of Coulomb interaction. This has recently be demonstrated by two groups [2-4] using hybrid quantum-dot devices with both superconducting and normal metal contacts. In the present talk, I will discuss the Cooper-pair splitter results from the Basel-Budapest-Copenhagen team and compare with the other experiments. As an outlook we discuss approaches that aim at entanglement detection. The Cooper pair splitter holds great promises because very large splitting efficiencies approaching 100% and large pair current rates appear feasible. This work has been done by L. Hofstetter, S. Csonka, A. Geresdi, M. Aagesen, J. Nygard and C. Schönenberger

  18. Theoretical analysis of novel fiber grating pair

    NASA Astrophysics Data System (ADS)

    Wang, Liao; Jia, Hongzhi; Fang, Liang; You, Bei

    2016-06-01

    A novel fiber grating pair that consists of a conventional long-period fiber grating and a fiber Bragg cladding grating (FBCG) is proposed. The FBCG is a new type of fiber grating in which refractive index modulation is formed in the cladding. Through the coupled-mode theory, we accurately calculate the coupling coefficients between modes supported in the fibers. And some other mode coupling features in the fiber cladding gratings are analyzed in detail. The calculation of the modes involved in this paper is based on a model of three-layer step-index fiber geometry. Then, we have investigated the sensitivity characteristics for variation of the modulation strengths of the fiber Bragg cladding gratings' resonance peaks and the long-period cladding gratings' (LPCGs) dual resonant peaks. Finally, the modulation strength sensitivity of the grating pair's three resonant peaks is demonstrated, and the results indicate that these grating pairs may find potential applications in optical fiber sensing.

  19. Entropy, area, and black hole pairs

    NASA Astrophysics Data System (ADS)

    Hawking, S. W.; Horowitz, Gary T.; Ross, Simon F.

    1995-04-01

    We clarify the relation between gravitational entropy and the area of horizons. We first show that the entropy of an extreme Reissner-Nordström black hole is zero, despite the fact that its horizon has nonzero area. Next, we consider the pair creation of extremal and nonextremal black holes. It is shown that the action which governs the rate of this pair creation is directly related to the area of the acceleration horizon and (in the nonextremal case) the area of the black hole event horizon. This provides a simple explanation of the result that the rate of pair creation of nonextreme black holes is enhanced by precisely the black hole entropy. Finally, we discuss black hole annihilation, and argue that Planck scale remnants are not sufficient to preserve unitarity in quantum gravity.

  20. Thermodynamics of pairing transition in hot nuclei

    NASA Astrophysics Data System (ADS)

    Liu, Lang; Zhang, Zhen-Hua; Zhao, Peng-Wei

    2015-10-01

    The pairing correlations in hot nuclei 162Dy are investigated in terms of the thermodynamical properties by covariant density functional theory. The thermodynamical quantities are evaluated by the canonical ensemble theory and the paring correlations are treated by a shell-model-like approach, in which the particle number is conserved exactly. An S-shaped heat capacity curve as a function of temperature has been obtained. The properties of hot nuclei, such as entropy and level density are studied in terms of defined seniority component. It is found that the one-pair-broken states play crucial roles in the appearance of the S shape of the heat capacity curve. Moreover, due to the effect of the particle-number conservation, the pairing gap varies smoothly with the temperature, which indicates a gradual transition from the superfluid to the normal state.

  1. A Pair Polarimeter for High Energy Photons

    NASA Astrophysics Data System (ADS)

    Tedeschi, David; Wojtsekhowski, B.; Khandaker, M.; Klein, F.; Feldman, G.; O'Rielly, G. V.; Vlahovic, B.

    2000-10-01

    The physics program at the Thomas Jefferson National Accelerator Facility includes fundamental experiments with polarized photon beams in the GeV energy range. To measure the degree of photon polarization, a photon polarimeter based on the detection of e^+e^- pairs has been developed for use in Hall B experiments. Recent progress in silicon micro-strip detectors allows for the measurement of the angle correlation in electron-positron pair production by high energy photons incident on an amorphous converter. Theoretical calculations of the pair production process show an asymmetry σ_allel/σ_⊥ ~ 1.7 in a wide range of photon energies. Experimental results obtained from 40 MeV photons at the Duke-FEL and 300 MeV photons from the Brookhaven-LEGS facility using prototype polarimeters will be presented.

  2. Hard Photodisintegration of a Proton Pair

    SciTech Connect

    Pomerantz, Ishay; Bubis, Nathaniel; Allada, Kalyan; Beck, Arie; Beck, Sara; Berman, Barry L.; Boeglin, Werner U.; Camsonne, Alexandre; Canan, Mustafa; Chirapatpimol, Khem; Cisbani, Evaristo; Cusanno, Francesco; de Jager, Cornelis W.; Dutta, Chirajib; Garibaldi, Franco; Geagla, Octavian; Gilman, Ronald; Glister, Jacqueline F.; Higinbotham, Douglas W.; Jiang, Xiaodong; Katramatou, A. T.; Khrosinkova, Elena; Lee, B. W.; LeRose, John J.; Lindgren, Richard A.; McCullough, Emily; Meekins, David G.; Michaels, Robert W.; Moffit, Bryan J.; Petratos, Gerassimos G.; Piasetzky, Eliazer I.; Qian, Xin; Qiang, Yi; Rodriguez, I.; Ron, Guy; Saha, Arun; Sarty, Adam J.; Sawatzky, Bradley D.; Schulte, Elaine C.; Shneor, Ran; Sparveris, NIkolaos; Subedi, Ramesh R.; Sulkosky, Vincent A.; Wang, Y.; Wojtsekhowski, Bogdan B.; Yan, X.; Yao, H.; Zhan, Xiaohui; Zheng, Xiaochao

    2010-01-08

    We present the first study of high energy photodisintegration of proton-pairs through the gamma + 3He -> p+p+n channel. Photon energies from 0.8 to 4.7 GeV were used in kinematics corresponding to a proton pair with high relative momentum and a neutron nearly at rest. An s^{-11} scaling of the cross section was observed, as predicted by the constituent counting rule. The onset of the scaling is at a higher energy and the cross section is significantly lower then for pn pair photodisintegration. For photon energies below the scaling region, the scaled cross section was found to present a strong energy-dependent structure not observed in deuteron photodisintegration.

  3. Hard Photodisintegration of a Proton Pair

    DOE PAGESBeta

    Pomerantz, Ishay; Bubis, Nathaniel; Allada, Kalyan; Beck, Arie; Beck, Sara; Berman, Barry L.; Boeglin, Werner U.; Camsonne, Alexandre; Canan, Mustafa; Chirapatpimol, Khem; et al

    2010-01-08

    We present the first study of high energy photodisintegration of proton-pairs through the gamma + 3He -> p+p+n channel. Photon energies from 0.8 to 4.7 GeV were used in kinematics corresponding to a proton pair with high relative momentum and a neutron nearly at rest. An s^{-11} scaling of the cross section was observed, as predicted by the constituent counting rule. The onset of the scaling is at a higher energy and the cross section is significantly lower then for pn pair photodisintegration. For photon energies below the scaling region, the scaled cross section was found to present a strongmore » energy-dependent structure not observed in deuteron photodisintegration.« less

  4. Induced Pairing Interaction in Neutron Star Matter

    NASA Astrophysics Data System (ADS)

    Lombardo, U.; Schulze, H.-J.; Zuo, W.

    2013-01-01

    The three superfluid phases supposed to occur in neutron stars are reviewed in the framework of the generalized BCS theory with the induced interaction. The structure of neutron stars characterized by beta-stable asymmetric nuclear matter in equilibrium with the gravitational force discloses new aspects of the pairing mechanism. Some of them are discussed in this report, in particular the formation in dense matter of Cooper pairs in the presence of three-body forces and the interplay between repulsive and attractive polarization effects on isospin T = 1 Cooper pairs embedded into the neutron and proton environment. Quantitative estimates of the energy gaps are reported and their sensitivity to the medium effects, i.e., interaction and polarization, is explored.

  5. Automated DNA Base Pair Calling Algorithm

    1999-07-07

    The procedure solves the problem of calling the DNA base pair sequence from two channel electropherogram separations in an automated fashion. The core of the program involves a peak picking algorithm based upon first, second, and third derivative spectra for each electropherogram channel, signal levels as a function of time, peak spacing, base pair signal to noise sequence patterns, frequency vs ratio of the two channel histograms, and confidence levels generated during the run. Themore » ratios of the two channels at peak centers can be used to accurately and reproducibly determine the base pair sequence. A further enhancement is a novel Gaussian deconvolution used to determine the peak heights used in generating the ratio.« less

  6. Breaking of Cooper pairs in 108Pd

    NASA Astrophysics Data System (ADS)

    Rahmatinejad, A.; Kakavand, T.; Razavi, R.

    2016-04-01

    In this paper, breaking of Cooper pairs in 108Pd is investigated within the canonical ensemble framework and the BCS model. Our results show an evidence of two phase transitions, which are related to neutron and proton systems. Also, with consideration of pairing interaction, the role of neutron and proton systems in entropy, spin cutoff parameter and as a result in the moment of inertia are investigated. The results show minor role for the proton system at low temperatures and approximately equal roles for both neutron and proton systems after the critical temperature. Good agreement was observed between obtained results and the experimental data.

  7. Comment on ``Pairing interaction and Galilei invariance''

    NASA Astrophysics Data System (ADS)

    Arias, J. M.; Gallardo, M.; Gómez-Camacho, J.

    1999-05-01

    A recent article by Dussel, Sofia, and Tonina studies the relation between Galilei invariance and dipole energy weighted sum rule (EWSR). The authors find that the pairing interaction, which is neither Galilei nor Lorentz invariant, produces big changes in the EWSR and in effective masses of the nucleons. They argue that these effects of the pairing force could be realistic. In this Comment we stress the validity of Galilei invariance to a very good approximation in this context of low-energy nuclear physics and show that the effective masses and the observed change in the EWSR for the electric dipole operator relative to its classical value are compatible with this symmetry.

  8. Photon pair generation in birefringent optical fibers

    NASA Astrophysics Data System (ADS)

    Smith, Brian J.; Mahou, P.; Cohen, Offir; Lundeen, J. S.; Walmsley, I. A.

    2009-12-01

    We study both experimentally and theoretically the generation of photon pairs by spontaneous four-wave mixing (SFWM) in standard birefringent optical fibers. The ability to produce a range of two-photon spectral states, from highly correlated (entangled) to completely factorable, by means of cross-polarized birefringent phase matching, is explored. A simple model is developed to predict the spectral state of the photon pair which shows how this can be adjusted by choosing the appropriate pump bandwidth, fiber length and birefringence. Spontaneous Raman scattering is modeled to determine the tradeoff between SFWM and background Raman noise, and the predicted results are shown to agree with experimental data.

  9. Multiscale structures in relativistic pair plasmas

    SciTech Connect

    Iqbal, M.; Berezhiani, V. I.; Yoshida, Z.

    2008-03-15

    The steady-state solution of a pair plasma with relativistic thermal velocity of the constituent particles (electrons and positrons) is investigated. The relaxed state can be written as a superposition of three Beltrami fields. Generally, the associated scale parameters could be a complex conjugate pair and a real one. It is shown that at higher thermal energies, all the scale parameters become real. It is also observed that one component gets a large scale (system size) while the other two components appear with small scale of the order of the skin depth at relativistic temperature.

  10. Paired Learning: Tutoring by Non-Teachers. Incorporating "The Paired Reading Bulletin" No. 5.

    ERIC Educational Resources Information Center

    Paired Reading Bulletin, 1989

    1989-01-01

    The eight papers constituting the Proceedings of the fourth National Paired Reading Conference are published in an annual bulletin of the Paired Reading Project, together with seven papers constituting the Supplementary Proceedings of the Peer Tutoring Conference, and nine feature articles, as follows: (1) "Whole-School Policy on Parental…

  11. Sexually antagonistic selection during parental care is not generated by a testosterone-related intralocus sexual conflict–insights from full-sib comparisons

    PubMed Central

    Iserbyt, Arne; Eens, Marcel; Müller, Wendt

    2015-01-01

    The evolution of shared male and female traits can be hampered if selection favours sex-specific optima. However, such genomic conflicts can be resolved when independent male and female mechanisms evolve. The existence, extent and consequences of conflict and/or conflict resolution are currently debated. Endocrinological traits like plasma testosterone (T) are suitable test cases, given their important role in mediating correlated traits, plus their opposing sex-specific fitness effects. We compared full-sibling (brother/sister) captive canaries to test for (1) sexually antagonistic selection characterized by contrasting fitness patterns within pairs of relatives, (2) intersexual genetic correlation of plasma T (h² = 0.41  ±  0.31) and (3) intralocus sexual conflict over T levels featured by distinct sex-specific fitness optima. We found potential for sexually antagonistic selection, since high fledgling mass was reached by either brothers or sisters, but not by both. We report a positive intersexual correlation for T, as a requirement for intralocus sexual conflict. However, high levels of T were associated with increased female and decreased male fitness (fledgling mass), which contrasts our expectations and challenges the hypothesis of intralocus sexual conflict driven by T. We hypothesize that behavioural and physiological trade-offs differ between sexes when raising offspring, driving T levels towards a state of monomorphism. PMID:26625951

  12. Sexually antagonistic selection during parental care is not generated by a testosterone-related intralocus sexual conflict-insights from full-sib comparisons.

    PubMed

    Iserbyt, Arne; Eens, Marcel; Müller, Wendt

    2015-01-01

    The evolution of shared male and female traits can be hampered if selection favours sex-specific optima. However, such genomic conflicts can be resolved when independent male and female mechanisms evolve. The existence, extent and consequences of conflict and/or conflict resolution are currently debated. Endocrinological traits like plasma testosterone (T) are suitable test cases, given their important role in mediating correlated traits, plus their opposing sex-specific fitness effects. We compared full-sibling (brother/sister) captive canaries to test for (1) sexually antagonistic selection characterized by contrasting fitness patterns within pairs of relatives, (2) intersexual genetic correlation of plasma T (h(²) = 0.41  ±  0.31) and (3) intralocus sexual conflict over T levels featured by distinct sex-specific fitness optima. We found potential for sexually antagonistic selection, since high fledgling mass was reached by either brothers or sisters, but not by both. We report a positive intersexual correlation for T, as a requirement for intralocus sexual conflict. However, high levels of T were associated with increased female and decreased male fitness (fledgling mass), which contrasts our expectations and challenges the hypothesis of intralocus sexual conflict driven by T. We hypothesize that behavioural and physiological trade-offs differ between sexes when raising offspring, driving T levels towards a state of monomorphism. PMID:26625951

  13. Pairing Content and Process: Some Observations.

    ERIC Educational Resources Information Center

    Fillenworth, Ceil; Rauch, Margaret

    Although a college program to retain high risk freshmen--those who fall below the 50th percentile of their graduating class--can result in increased academic success, a number of concerns must be addressed. The structure of one such program contains three components: the paired course curriculum, a career planning and personal goal exploration…

  14. RNA Matchmaking: Finding Cellular Pairing Partners.

    PubMed

    Graveley, Brenton R

    2016-07-21

    RNA structure is intimately related to function, yet methods to identify base-paired RNA strands in a transcriptome-wide manner in cells have remained elusive. One recent paper in Cell and two in Molecular Cell describe related methods to identify RNA sequences that interact in living cells, setting the stage for breakthroughs in our understanding of RNA structure and function. PMID:27447984

  15. Chemical Nonlinearities and Radical Pair Lifetime Estimation

    NASA Astrophysics Data System (ADS)

    Robinson, Gregory

    2013-03-01

    Much attention has recently developed around chemical reactions that depend on applied static magnetic fields as weak as earth's. This interest is largely motivated by experiments that implicate the role of spin-selective radical pair recombination in biological magnetic sensing. Existing literature uses a straightforward calculation to approximate the expected lifetime of coherent radical pairs as a function of the minimum RF amplitude that is observed to disrupt magnetic navigation, apparently by decohering the radical pair via electronic Zeeman excitations. But we show that chemical nonlinearities can preclude direct computation of coherent pair lifetime without considering the cellular signalling mechanisms involved, and discuss whether it can explain the surprising fragility of some animals' compass sense. In particular, we demonstrate that an autocatalytic cycle can introduce threshold effects on the disruption sensitivity to applied oscillatory magnetic fields. We will show examples in the mean-field limit and consider the consequences of noise and fluctuations in the Freidlin-Wentzell picture of perturbed dynamical systems.

  16. The Paired-Object Affordance Effect

    ERIC Educational Resources Information Center

    Yoon, Eun Young; Humphreys, Glyn W.; Riddoch, M. Jane

    2010-01-01

    We demonstrate that right-handed participants make speeded classification responses to pairs of objects that appear in standard co-locations for right-handed actions relative to when they appear in reflected locations. These effects are greater when participants "weight" information for action when deciding if 2 objects are typically used…

  17. Assessing Paired Orals: Raters' Orientation to Interaction

    ERIC Educational Resources Information Center

    Ducasse, Ana Maria; Brown, Annie

    2009-01-01

    Speaking tasks involving peer-to-peer candidate interaction are increasingly being incorporated into language proficiency assessments, in both large-scale international testing contexts, and in smaller-scale, for example course-related, ones. This growth in the popularity and use of paired and group orals has stimulated research, particularly into…

  18. Promoting Paired Placements in Initial Teacher Education

    ERIC Educational Resources Information Center

    King, Sheila

    2006-01-01

    The use of paired placements and collaborative practice is promoted by many university-school partnerships that train teachers in England. This paper reviews the recent literature on the subject and then focuses on some small scale research within initial teacher education in one large university-school partnership. That partnership works with…

  19. Pairing, pseudogap and Fermi arcs in cuprates

    DOE PAGESBeta

    Kaminski, Adam; Kondo, Takeshi; Takeuchi, Tsunehiro; Gu, Genda

    2014-04-29

    We use Angle Resolved Photoemission Spectroscopy (ARPES) to study the relationship between the pseudogap, pairing and Fermi arcs in cuprates. High quality data measured over a wide range of dopings reveals a consistent picture of Fermiology and pairing in these materials. The pseudogap is due to an ordered state that competes with superconductivity rather than preformed pairs. Pairing does occur below Tpair ~ 150K and significantly above Tc, but well below T* and the doping dependence of this temperature scale is distinct from that of the pseudogap. The d-wave gap is present below Tpair, and its interplay with strong scatteringmore » creates “artificial” Fermi arcs for Tc ≤ T ≤ Tpair. However, above Tpair, the pseudogap exists only at the antipodal region. This leads to presence of real, gapless Fermi arcs close to the node. The length of these arcs remains constant up to T*, where the full Fermi surface is recovered. As a result, we demonstrate that these findings resolve a number of seemingly contradictory scenarios.« less

  20. Plasma analog of particle-pair production

    SciTech Connect

    Tsidulko, Yu.A.; Berk, H.L.

    1996-09-01

    It is shown that the plasma axial shear flow instability satisfies the Klein-Gordon equation. The plasma instability is then shown to be analogous to spontaneous particle-pair production when a potential energy is present that is greater than twice the particle rest mass energy. Stability criteria can be inferred based on field theoretical conservation laws.

  1. Turbulent Particle Pair Diffusion Using Kinematic Simulations

    NASA Astrophysics Data System (ADS)

    Malik, Nadeem

    2015-11-01

    Sweeping errors in Kinematic Simulations (KS) have been shown to be negligible in turbulent flows with extended inertial subranges up to at least 1pair diffusivity K = < Δ . v > in KS may therefore be a genuine effect, challenging previous assumptions that in turbulence with generalized power-law energy spectra, E (k) ~k-p for 1 <= 3, locality would lead to, K ~σΔγ , where σΔ = [ <Δ2 > ]1/2 , Δ is the pair separation, v is the pair relative velocity, < > is the ensemble average, and γ = (1 + p) / 2 . For Kolmogorov turbulence this gives, K ~σΔ4 / 3 . A new analysis, supported by KS confirms that both local and non-local effects govern the pair diffusion process, leading to, K ~σΔγp , where now γp > γ for Kolmogorov turbulence, K ~σΔ1 . 53 . Thus non-local diffusional processes cannot be neglected, and this may have important consequences for the general theory of turbulence. The author acknowledge financial support from SABIC, #SB101011.

  2. Two New CPM Pairs in Libra

    NASA Astrophysics Data System (ADS)

    Ahad, Abdul

    2014-10-01

    In this paper two new double stars are reported in the constellation of Libra that are currently not in the WDS catalog, the components of which share common proper motions. On observed photometric characteristics, calibration of distances, and other assumptions, all the indications are that both pairs comprise possible wide physical systems.

  3. A Novel Approach for Collaborative Pair Programming

    ERIC Educational Resources Information Center

    Goel, Sanjay; Kathuria, Vanshi

    2010-01-01

    The majority of an engineer's time in the software industry is spent working with other programmers. Agile methods of software development like eXtreme Programming strongly rely upon practices like daily meetings and pair programming. Hence, the need to learn the skill of working collaboratively is of primary importance for software developers.…

  4. Twisted Pair Of Insulated Wires Senses Moisture

    NASA Technical Reports Server (NTRS)

    Laue, Eric G.; Stephens, James B.

    1989-01-01

    Sensitivity of electronic moisture sensor to low levels of moisture increased by new electrode configuration. Moisture-sensing circuit described in "Low-Cost Humidity Sensor" (NPO-16544). New twisted pair of wires takes place of flat-plate capacitor in circuit. Configuration allows for thermal expansion and contraction of polymer while maintaining nearly constant area of contact between polymer and wires.

  5. Primordial nuggets survival and QCD pairing

    NASA Astrophysics Data System (ADS)

    Lugones, G.; Horvath, J. E.

    2004-03-01

    We reexamine the problem of boiling and surface evaporation of quark nuggets in the cosmological quark-hadron transition with the explicit consideration of pairing between quarks in a color-flavor locked state. Assuming that primordial quark nuggets are actually formed, we analyze the consequences of pairing on the rates of boiling and surface evaporation in order to determine whether they could have survived with substantial mass. We find a substantial quenching of the evaporation+boiling processes, which suggests the survival of primordial nuggets for the currently considered range of the pairing gap Δ. Boiling is shown to depend on the competition of an increased stability window and the suppression of the rate, and is not likely to dominate the destruction of the nuggets. If surface evaporation dominates, the fate of the nuggets depends on the features of the initial mass spectrum of the nuggets, their evaporation rate, and the value of the pairing gap, as shown and discussed in the text.

  6. Ion Pairing in Alkali Nitrate Electrolyte Solutions.

    PubMed

    Xie, Wen Jun; Zhang, Zhen; Gao, Yi Qin

    2016-03-10

    In this study, we investigate the thermodynamics of alkali nitrate salt solutions, especially the formation of contact ion pairs between alkali cation and nitrate anion. The ion-pairing propensity shows an order of LiNO3 < NaNO3 < KNO3. Such results explain the salt activity coefficients and suggest that the empirical "law of matching water affinity" is followed by these alkali nitrate salt solutions. The spatial patterns of contact ion pairs are different in the three salt solutions studied here: Li(+) forms the contact ion pair with only one oxygen of the nitrate while Na(+) and K(+) can also be shared by two oxygens of the nitrate. In reproducing the salt activity coefficient using Kirkwood-Buff theory, we find that it is essential to include electronic polarization for Li(+) which has a high charge density. The electronic continuum correction for nonpolarizable force field significantly improves the agreement between the calculated activity coefficients and their experimental values. This approach also improves the performance of the force field on salt solubility. From these two aspects, this study suggests that electronic continuum correction can be a promising approach to force-field development for ions with high charge densities. PMID:26901167

  7. Pairing the Adult Learner and Boutique Wineries

    ERIC Educational Resources Information Center

    Holyoke, Laura; Heath-Simpson, Delta

    2013-01-01

    This study explored connections between adult learners and their experiences in the context of small boutique wineries operating in the start-up phase of the organizational life cycle. The research objective was to gain insight regarding the pairing of adult learners with the entering of a specialty industry. Fourteen individuals from four…

  8. Two-photon production of ω pairs

    NASA Astrophysics Data System (ADS)

    Albrecht, H.; Hamacher, T.; Hofmann, R. P.; Kirchhoff, T.; Mankel, R.; Nau, A.; Nowak, S.; Reßing, D.; Schröder, H.; Schulz, H. D.; Walter, M.; Wurth, R.; Hast, C.; Kapitza, H.; Kolanoski, H.; Kosche, A.; Lange, A.; Lindner, A.; Schieber, M.; Siegmund, T.; Spaan, B.; Thurn, H.; Töpfer, D.; Wegener, D.; Eckstein, P.; Frankl, C.; Graf, J.; Schmidtler, M.; Schramm, M.; Schubert, K. R.; Schwierz, R.; Waldi, R.; Reim, K.; Wegener, H.; Eckmann, R.; Kuipers, H.; Mai, O.; Mundt, R.; Oest, T.; Reiner, R.; Schmidt-Parzefall, W.; Stiewe, J.; Werner, S.; Ehret, K.; Hofmann, W.; Hüpper, A.; Knöpfle, K. T.; Spengler, J.; Krieger, P.; Macfarlane, D. B.; Prentice, J. D.; Saull, P. R. B.; Tzamariudaki, K.; van de Water, R. G.; Yoon, T.-S.; Schneider, M.; Weseler, S.; Kernel, G.; Križan, P.; Križnič, E.; Podobnik, T.; Živko, T.; Balagura, V.; Barsuk, S.; Belyaev, I.; Chistov, R.; Danilov, M.; Eiges, V.; Gershtein, L.; Gershtein, Yu.; Golutvin, A.; Igonkina, O.; Korolko, I.; Kostina, G.; Litvintsev, D.; Pakhlov, P.; Semenov, S.; Snizhko, A.; Tichomirov, I.; Zaitsev, Yu.; Argus Collaboration

    1996-02-01

    A maximum likelihood analysis of ARGUS data on two-photon production of π+π+π0π0π-π- is presented. A small fraction of events is due to the production of omega pairs. The γγ → ωω cross section has its maximum value close to threshold.

  9. Relaxed States in Magnetized Pair Plasmas

    NASA Astrophysics Data System (ADS)

    Shukla, P. K.; Mahajan, S. M.

    2004-01-01

    We discuss possibility of possible relaxed states in magnetized pair plasmas. It is shown that stationary relaxed states are described by the double curl Beltrami/Mahajan-Yoshida equation. We can thus have steady state tructures on the scale sizes of the order of the electron (ion) skin depth in an electron-positron (electron-positron-ion) plasma.

  10. Chaotic scattering of two vortex pairs

    NASA Astrophysics Data System (ADS)

    Tophøj, Laust; Aref, Hassan

    2008-11-01

    Chaotic scattering of two vortex pairs with slightly different circulations was considered by Eckhardt & Aref in 1988. A new numerical exploration suggests that the motion of two vortex pairs, with constituent vortices all of the same absolute circulation, also displays chaotic scattering regimes. The mechanisms leading to chaotic scattering are different from the ``slingshot effect'' identified by Price [Phys. Fluids A, 5, 2479 (1993)] and occur in a different region of the four-vortex phase space. They may in many cases be understood by appealing to the solutions of the three-vortex problem obtained by merging two like-signed vortices into one of twice the strength, and by assuming that the four-vortex problem has unstable, periodic solutions similar to those seen in the thereby associated three-vortex problems. The integrals of motion, linear impulse and Hamiltonian, are recast in a form appropriate for vortex pair scattering interactions that provides constraints on the parameters characterizing the outgoing vortex pairs in terms of the initial conditions.

  11. An essential non-Watson-Crick base pair motif in 3'UTR to mediate selenoprotein translation.

    PubMed Central

    Walczak, R; Carbon, P; Krol, A

    1998-01-01

    The SECIS element is an RNA hairpin in the 3'UTR of selenoprotein mRNAs required for decoding UGA selenocysteine codons. Our experimentally derived 2D structure model for the SECIS RNA revealed the conservation of four consecutive non-Watson-Crick base pairs, with a central G.A/A.G tandem. The present study was dedicated to gaining insight into the role of this quartet of base pairs. The effects of mutations introduced into the SECIS quartet of the glutathione peroxidase (GPx) cDNA, an enzyme with selenocysteine in its active center, were reported in vivo by the GPx activity. The detrimental consequence of an all-Watson-Crick mutant quartet disclosed the paramount importance of the non-Watson-Crick base pairs for GPx activity. Next, structure probing established that base pair changes in the central G.A/A.G tandem, predicted by the model to be structurally unfavorable, effectively led to local opening of the helix at the quartet. A concomitant abolition of GPx activity was observed, arising from translational impairment of full-length GPx. In contrast, an isosteric base pair replacement in the tandem did not affect base pairing in the quartet, leading to an almost wt GPx activity. Collectively, the data provided conclusive evidence for the functional relevance of these non-Watson-Crick base pairs in vivo, thus identifying a noncanonical RNA motif crucial to SECIS function in mediating selenoprotein translation. Within the quartet, the prominent requirement for the central G.A/A.G tandem is highlighted, our previous structural model and the mutagenesis data presented here strongly arguing in favor of a sheared arrangement for the G.A base pairs. The SECIS RNA is therefore another member to be added to the growing list of RNAs containing building blocks of non-Watson-Crick base pairs, required for structure and/or function. PMID:9436910

  12. A Microanalytic Perspective on Discourse, Proficiency, and Identity in Paired Oral Assessment

    ERIC Educational Resources Information Center

    Lazaraton, Anne; Davis, Larry

    2008-01-01

    The increasing popularity of paired format in oral testing has engendered legitimate scrutiny of its reliability and validity as compared with the more traditional interviewer-interviewee arrangement. Although characteristics such as the gender, cultural/L1 background, and language proficiency of one's interlocutor likely affects the discourse…

  13. Motor Impairment in Sibling Pairs Concordant and Discordant for Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Hilton, Claudia List; Zhang, Yi; Whilte, Megan R.; Klohr, Cheryl L.; Constantino, John

    2012-01-01

    Aim: Although motor impairment is frequently observed in children with autism spectrum disorders (ASD), the manner in which these impairments aggregate in families affected by autism is unknown. We used a standardized measure of motor proficiency to objectively examine quantitative variation in motor proficiency in sibling pairs concordant and…

  14. Failure to find linkage between a functional polymorphism in the dopamine D4 receptor gene and schizophrenia

    SciTech Connect

    Shaikh, S.; Gill, M.; Collier, D.A.

    1994-03-15

    We report the results of a linkage study in 24 families multiply affected with schizophrenia using a polymorphic DNA sequence encoding the third cytoplasmic loop of the dopamine D4 receptor. Two-point LOD score analyses with a range of single gene models ranging from near dominant to near recessive revealed no evidence for linkage. In addition, we examined the data by non-parametric sib-pair analysis and found no excess sharing of alleles between affected sib-pairs. We therefore conclude that mutations within the dopamine D4 receptor gene do not have a major aetiological role in schizophrenia in our collection of pedigrees. 20 refs., 2 tabs.

  15. Effect of base-pair stability of nearest-neighbor nucleotides on the fidelity of deoxyribonucleic acid synthesis.

    PubMed

    Patten, J E; So, A G; Downey, K M

    1984-04-10

    The influence of the stability of base pairs formed by nearest-neighbor nucleotides on misincorporation frequency has been studied with the large fragment of DNA polymerase I, the alternating DNA copolymers, poly(dI-dC) and poly-(dG-dC), as template-primers, and dGTP, dITP, and dCTP as substrates. We have utilized the difference in thermodynamic stability between the doubly H-bonded I X C base pair and triply H-bonded G X C base pair to examine the effects of base-pair stability of both the "preceding" and the "following" nucleotides on the frequency of insertion of a mismatched nucleotide, as well as on its stable incorporation into polynucleotide. The present studies demonstrate that the stability of the base pairs formed by nearest-neighbor nucleotides affects the frequency of incorporation of noncomplementary nucleotides. Misincorporation frequency is increased when the nearest-neighbor nucleotides form more stable base pairs with the corresponding nucleotides in the template and is decreased when they form less stable base pairs. The stability of the base pair formed by a nucleotide either preceding (5' to) or following (3' to) a misincorporated nucleotide influences misincorporation frequency, but by different mechanisms. The stability of base pairs formed by preceding nucleotides affects the rate of insertion of mismatched nucleotide but does not protect the mismatched nucleotide from removal by the 3' to 5' exonuclease activity. In contrast, the stability of a base pair formed by a following nucleotide determines whether a misincorporated nucleotide is extended or excised by affecting the ability of the enzyme to edit errors of incorporation. PMID:6722115

  16. Recombination locations and rates in beef cattle assessed from parent-offspring pairs

    PubMed Central

    2014-01-01

    Background Recombination events tend to occur in hotspots and vary in number among individuals. The presence of recombination influences the accuracy of haplotype phasing and the imputation of missing genotypes. Genes that influence genome-wide recombination rate have been discovered in mammals, yeast, and plants. Our aim was to investigate the influence of recombination on haplotype phasing, locate recombination hotspots, scan the genome for Quantitative Trait Loci (QTL) and identify candidate genes that influence recombination, and quantify the impact of recombination on the accuracy of genotype imputation in beef cattle. Methods 2775 Angus and 1485 Limousin parent-verified sire/offspring pairs were genotyped with the Illumina BovineSNP50 chip. Haplotype phasing was performed with DAGPHASE and BEAGLE using UMD3.1 assembly SNP (single nucleotide polymorphism) coordinates. Recombination events were detected by comparing the two reconstructed chromosomal haplotypes inherited by each offspring with those of their sires. Expected crossover probabilities were estimated assuming no interference and a binomial distribution for the frequency of crossovers. The BayesB approach for genome-wide association analysis implemented in the GenSel software was used to identify genomic regions harboring QTL with large effects on recombination. BEAGLE was used to impute Angus genotypes from a 7K subset to the 50K chip. Results DAGPHASE was superior to BEAGLE in haplotype phasing, which indicates that linkage information from relatives can improve its accuracy. The estimated genetic length of the 29 bovine autosomes was 3097 cM, with a genome-wide recombination distance averaging 1.23 cM/Mb. 427 and 348 windows containing recombination hotspots were detected in Angus and Limousin, respectively, of which 166 were in common. Several significant SNPs and candidate genes, which influence genome-wide recombination were localized in QTL regions detected in the two breeds. High

  17. On the wobble GoU and related pairs.

    PubMed Central

    Masquida, B; Westhof, E

    2000-01-01

    The wobble GoU pairs have been implicated in several biological processes where RNA molecules play a key role. We review the geometrical and conformational properties of wobble GoU pairs on the basis of available crystal structures of RNAs at high resolution. The similarities with the wobble A+oC pairs and UoU pairs are illustrated, while the differences with the recently discovered bifurcated G x U pairs are contrasted. PMID:10668794

  18. Contact Pairing Interaction for the Hartree-Fock-Bogoliubov Calculations

    SciTech Connect

    Dobaczewski, J.

    2001-10-18

    Properties of density-dependent contact pairing interactions in nuclei are discussed. It is shown that the pairing interaction that is intermediate between surface and volume pairing forces gives the pairing gaps that are compatible with the experimental odd-even mass staggering. Results of the deformed Hartree-Fock-Bogoliubov calculations for this ''mixed'' pairing interaction, and using the transformed harmonic oscillator basis, are presented.

  19. Electron-pair excitations and the molecular Coulomb continuum

    SciTech Connect

    Colgan, James

    2009-01-01

    Electron-pair excitations in the molecular hydrogen continuum are described by quantizing rotations of the momentum plane of the electron pair about by the pair's relative momentum. A helium-like description of the molecular pi.Joto double ionization is thus extended to higher angular momenta of the electron pair. A simple three-state superposition is found to account surprisingly well for recent observations of noncoplanar electron-pair, molecular-axis angular distributions.

  20. Pair instability supernovae of very massive population III stars

    SciTech Connect

    Chen, Ke-Jung; Woosley, Stan; Heger, Alexander; Almgren, Ann; Whalen, Daniel J.

    2014-09-01

    Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III stars with initial masses of 140-260 M {sub ☉} die as highly energetic pair-instability supernovae. We present new two-dimensional simulations of primordial pair-instability supernovae done with the CASTRO code. Our simulations begin at earlier times than previous multidimensional models, at the onset of core contraction, to capture any dynamical instabilities that may be seeded by core contraction and explosive burning. Such instabilities could enhance explosive yields by mixing hot ash with fuel, thereby accelerating nuclear burning, and affect the spectra of the supernova by dredging up heavy elements from greater depths in the star at early times. Our grid of models includes both blue supergiants and red supergiants over the range in progenitor mass expected for these events. We find that fluid instabilities driven by oxygen and helium burning arise at the upper and lower boundaries of the oxygen shell ∼20-100 s after core bounce. Instabilities driven by burning freeze out after the SN shock exits the helium core. As the shock later propagates through the hydrogen envelope, a strong reverse shock forms that drives the growth of Rayleigh-Taylor instabilities. In red supergiant progenitors, the amplitudes of these instabilities are sufficient to mix the supernova ejecta.

  1. Initiative, Personality and Leadership in Pairs of Foraging Fish

    PubMed Central

    Nakayama, Shinnosuke; Harcourt, Jennifer L.; Johnstone, Rufus A.; Manica, Andrea

    2012-01-01

    Studies of coordinated movement have found that, in many animal species, bolder individuals are more likely to initiate movement and shyer individuals to follow. Here, we show that in pairs of foraging stickleback fish, leadership is not merely a passive consequence of temperamental differences. Instead, the act of initiating a joint foraging trip out of cover itself brings about a change in the role that an individual plays throughout the subsequent trip, and success in recruiting a partner affects an individual's tendency to initiate the next trip. On each joint trip, whichever fish took the initiative in leading out of cover gains greater influence over its partner's behaviour, which persists even after several changes in position (i.e. termination attempts and re-joining). During any given trip, the initiator is less responsive to its partner's movements than during trips initiated by the partner. An individual's personality had an important effect on its response to failure to recruit a partner: while bold fish were unaffected by failures to initiate a joint trip, shy individuals were less likely to attempt another initiation after a failure. This difference provides a positive feedback mechanism that can partially stabilise social roles within the pair, but it is not strong enough to prevent occasional swaps, with individuals dynamically adjusting their responses to one another as they exchange roles. PMID:22567168

  2. Paired associative transspinal and transcortical stimulation produces plasticity in human cortical and spinal neuronal circuits.

    PubMed

    Dixon, Luke; Ibrahim, Mohamed M; Santora, Danielle; Knikou, Maria

    2016-08-01

    Anatomical, physiological, and functional connectivity exists between the neurons of the primary motor cortex (M1) and spinal cord. Paired associative stimulation (PAS) produces enduring changes in M1, based on the Hebbian principle of associative plasticity. The present study aimed to establish neurophysiological changes in human cortical and spinal neuronal circuits by pairing noninvasive transspinal stimulation with transcortical stimulation via transcranial magnetic stimulation (TMS). We delivered paired transspinal and transcortical stimulation for 40 min at precise interstimulus intervals, with TMS being delivered after (transspinal-transcortical PAS) or before (transcortical-transspinal PAS) transspinal stimulation. Transspinal-transcortical PAS markedly decreased intracortical inhibition, increased intracortical facilitation and M1 excitability with concomitant decreases of motor threshold, and reduced the soleus Hoffmann's reflex (H-reflex) low frequency-mediated homosynaptic depression. Transcortical-transspinal PAS did not affect intracortical circuits, decreased M1 excitability, and reduced the soleus H-reflex-paired stimulation pulses' mediated postactivation depression. Both protocols affected the excitation threshold of group Ia afferents and motor axons. These findings clearly indicate that the pairing of transspinal with transcortical stimulation produces cortical and spinal excitability changes based on the timing interval and functional network interactions between the two associated inputs. This new PAS paradigm may constitute a significant neuromodulation method with physiological impact, because it can be used to alter concomitantly excitability of intracortical circuits, corticospinal neurons, and spinal inhibition in humans. PMID:27281748

  3. Determination of the pairing-strength constants in the isovector plus isoscalar pairing case

    NASA Astrophysics Data System (ADS)

    Mokhtari, D.; Fellah, M.; Allal, N. H.

    2016-05-01

    A method for the determination of the pairing-strength constants, in the neutron-proton (n-p) isovector plus isoscalar pairing case, is proposed in the framework of the BCS theory. It is based on the fitting of these constants to reproduce the experimentally known pairing gap parameters as well as the root-mean-squared (r.m.s) charge radii values. The method is applied to some proton-rich even-even nuclei. The single-particle energies used are those of a deformed Woods-Saxon mean field. It is shown that the obtained value of the ratio GnpT=0/G npT=1 is of the same order as the ones, arbitrary chosen, of some previous works. The effect of the inclusion of the isoscalar n-p pairing in the r.m.s matter radii is then numerically studied for the same nuclei.

  4. Pairing and anti-pairing: a balancing act in the diploid genome

    PubMed Central

    Joyce, Eric F.; Erceg, Jelena; Wu, C.-ting

    2016-01-01

    The presence of maternal and paternal homologs appears to be much more than just a doubling of genetic material. We know this because genomes have evolved elaborate mechanisms that permit homologous regions to sense and then respond to each other. One way in which homologs communicate is to come into contact and, in fact, Dipteran insects such as Drosophila excel at this task, aligning all pairs of maternal and paternal chromosomes, end-to-end, in essentially all somatic tissues throughout development. Here, we reexamine the widely held tenet that extensive somatic pairing of homologous sequences cannot occur in mammals and suggest, instead, that pairing may be a widespread and significant potential that has gone unnoticed in mammals because they expend considerable effort to prevent it. We then extend this discussion to interchromosomal interactions, in general, and speculate about the potential of nuclear organization and pairing to impact inheritance. PMID:27065367

  5. Pairing and anti-pairing: a balancing act in the diploid genome.

    PubMed

    Joyce, Eric F; Erceg, Jelena; Wu, C-Ting

    2016-04-01

    The presence of maternal and paternal homologs appears to be much more than just a doubling of genetic material. We know this because genomes have evolved elaborate mechanisms that permit homologous regions to sense and then respond to each other. One way in which homologs communicate is to come into contact and, in fact, Dipteran insects such as Drosophila excel at this task, aligning all pairs of maternal and paternal chromosomes, end-to-end, in essentially all somatic tissues throughout development. Here, we reexamine the widely held tenet that extensive somatic pairing of homologous sequences cannot occur in mammals and suggest, instead, that pairing may be a widespread and significant potential that has gone unnoticed in mammals because they expend considerable effort to prevent it. We then extend this discussion to interchromosomal interactions, in general, and speculate about the potential of nuclear organization and pairing to impact inheritance. PMID:27065367

  6. Resonant tunneling of fluctuation Cooper pairs

    SciTech Connect

    Galda, Alexey; Mel'nikov, A. S.; Vinokur, V. M.

    2015-02-09

    Superconducting fluctuations have proved to be an irreplaceable source of information about microscopic and macroscopic material parameters that could be inferred from the experiment. According to common wisdom, the effect of thermodynamic fluctuations in the vicinity of the superconducting transition temperature, Tc, is to round off all of the sharp corners and discontinuities, which otherwise would have been expected to occur at Tc. Here we report the current spikes due to radiation-induced resonant tunneling of fluctuation Cooper pairs between two superconductors which grow even sharper and more pronounced upon approach to Tc. This striking effect offers an unprecedented tool for direct measurements of fluctuation Cooper pair lifetime, which is key to our understanding of the fluctuation regime, most notably to nature of the pseudogap state in high-temperature superconductors. Our finding marks a radical departure from the conventional view of superconducting fluctuations as a blurring and rounding phenomenon.

  7. Dual Resolution Images from Paired Fingerprint Cards

    National Institute of Standards and Technology Data Gateway

    NIST Dual Resolution Images from Paired Fingerprint Cards (PC database for purchase)   NIST Special Database 30 is being distributed for use in development and testing of fingerprint compression and fingerprint matching systems. The database allows the user to develop and evaluate data compression algorithms for fingerprint images scanned at both 19.7 ppmm (500 dpi) and 39.4 ppmm (1000 dpi). The data consist of 36 ten-print paired cards with both the rolled and plain images scanned at 19.7 and 39.4 pixels per mm. A newer version of the compression/decompression software on the CDROM can be found at the website http://www.nist.gov/itl/iad/ig/nigos.cfm as part of the NBIS package.

  8. Geometrical limitations in grating pair pulse compression

    SciTech Connect

    Brorson, S.D.; Haus, H.A.

    1988-01-01

    Optical-pulse compression using gratings has become a standard technique for producing ultrafast pulses outside a laser cavity. Short pulses produced by a mode-locked laser are focused into an optical fiber. There, self-phase modulation and group velocity dispersion act to broaden the bandwidth of the pulse and impart to it a negative chirp. A pair of diffraction gratings are placed following the fiber. Different frequencies follow different paths through the grating pair; if they are properly oriented, the gratings can compensate for the linear chirp of the pulse. In this way the spectral components of the pulse are compressed in time. The net effect of the system is to produce an output pulse that is shorter than the input pulse because of the additional frequencies generated in the fiber.

  9. Satellite observations of transionospheric pulse pairs

    SciTech Connect

    Holden, D.N.; Munson, C.P.; Devenport, J.C.

    1995-04-15

    The BLACKBEARD payload aboard the ALEXIS satellite has been making broadband observations in the VHF band of the radio spectrum. Since November of 1993 several hundred unusual signals have been recorded. The peculiar nature of these bursts of radio noise is that they have a duration of approximately 10 {mu}sec, are typically 20 to 40 dB brighter than the average background, and occur in pairs separated by approximately 50 {mu}sec. The authors have dubbed these emissions TransIonospheric Pulse Pairs, or TIPP events. They do not know what the source of these emissions is, but the dispersion of these signals is consistent with an origin at or near the earth`s surface. The satellite field of view and time of day when TIPP events are generally detected are consistent with regions of thunderstorm activity such as south-central Africa or Indonesia. 4 refs., 5 figs.

  10. The Radical-Pair Mechanism of Magnetoreception.

    PubMed

    Hore, P J; Mouritsen, Henrik

    2016-07-01

    Although it has been known for almost half a century that migratory birds can detect the direction of the Earth's magnetic field, the primary sensory mechanism behind this remarkable feat is still unclear. The leading hypothesis centers on radical pairs-magnetically sensitive chemical intermediates formed by photoexcitation of cryptochrome proteins in the retina. Our primary aim here is to explain the chemical and physical aspects of the radical-pair mechanism to biologists and the biological and chemical aspects to physicists. In doing so, we review the current state of knowledge on magnetoreception mechanisms. We dare to hope that this tutorial will stimulate new interdisciplinary experimental and theoretical work that will shed much-needed additional light on this fascinating problem in sensory biology. PMID:27216936

  11. Dissipative solitons in pair-ion plasmas

    SciTech Connect

    Ghosh, Samiran; Adak, Ashish Khan, Manoranjan

    2014-01-15

    The effects of ion-neutral collisions on the dynamics of the nonlinear ion acoustic wave in pair-ion plasma are investigated. The standard perturbative approach leads to a Korteweg-de Vries equation with a linear damping term for the dynamics of the finite amplitude wave. The ion-neutral collision induced dissipation is responsible for the linear damping. The analytical solution and numerical simulation reveal that the nonlinear wave propagates in the form of a weakly dissipative compressive solitons. Furthermore, the width of the soliton is proportional to the amplitude of the wave for fixed soliton velocity. Results are discussed in the context of the fullerene pair-ion plasma experiment.

  12. Locomotion gaits of a rotating cylinder pair

    NASA Astrophysics Data System (ADS)

    van Rees, Wim M.; Novati, Guido; Koumoutsakos, Petros; Mahadevan, L.

    2015-11-01

    Using 2D numerical simulations of the Navier-Stokes equations, we demonstrate that a simple pair of rotating cylinders can display a range of locomotion patterns of biological and engineering interest. Steadily counter-rotating the cylinders causes the pair to move akin to a vortex dipole for low rotation rates, but as the rotational velocity is increased the direction of motion reverses. Unsteady rotations lead to different locomotion gaits that resemble jellyfish (for in-phase rotations) and undulating swimmers (for out-of-phase rotations). The small number of parameters for this simple system allows us to systematically map the phase space of these gaits, and allows us to understand the underlying physical mechanisms using a minimal model with implications for biological locomotion and engineered analogs.

  13. Schwinger pair production with ultracold atoms

    NASA Astrophysics Data System (ADS)

    Kasper, V.; Hebenstreit, F.; Oberthaler, M. K.; Berges, J.

    2016-09-01

    We consider a system of ultracold atoms in an optical lattice as a quantum simulator for electron-positron pair production in quantum electrodynamics (QED). For a setup in one spatial dimension, we investigate the nonequilibrium phenomenon of pair production including the backreaction leading to plasma oscillations. Unlike previous investigations on quantum link models, we focus on the infinite-dimensional Hilbert space of QED and show that it may be well approximated by experiments employing Bose-Einstein condensates interacting with fermionic atoms. Numerical calculations based on functional integral techniques give a unique access to the physical parameters required to realize QED phenomena in a cold atom experiment. In particular, we use our approach to consider quantum link models in a yet unexplored parameter regime and give bounds for their ability to capture essential features of the physics. The results suggest a paradigmatic change towards realizations using coherent many-body states for quantum simulations of high-energy particle physics phenomena.

  14. Pair correlations in neutron-rich nuclei

    SciTech Connect

    Esbensen, H.

    1995-08-01

    We started a program to study the ground-state properties of heavy, neutron-rich nuclei using the Hartree-Fock-Bogolyubov (HFB) approximation. This appears at present to be the most realistic approach for heavy nuclei that contain many loosely bound valence neutrons. The two-neutron density obtained in this approach can be decomposed into two components, one associated with the mean field and one associated with the pairing field. The latter has a structure that is quite similar to the pair-density obtained by diagonalizing the Hamiltonian for a two-neutron halo, which was studied earlier. This allows comparison of the HFB solutions against numerically exact solutions for two-neutron halos. This work is in progress. We intend to apply the HFB method to predict the ground-state properties of heavier, more neutron-rich nuclei that may be produced at future radioactive beam facilities.

  15. Dynamics and Instabilities of Vortex Pairs

    NASA Astrophysics Data System (ADS)

    Leweke, Thomas; Le Dizès, Stéphane; Williamson, Charles H. K.

    2016-01-01

    This article reviews the characteristics and behavior of counter-rotating and corotating vortex pairs, which are seemingly simple flow configurations yet immensely rich in phenomena. Since the reviews in this journal by Widnall (1975) and Spalart (1998) , who studied the fundamental structure and dynamics of vortices and airplane trailing vortices, respectively, there have been many analytical, computational, and experimental studies of vortex pair flows. We discuss two-dimensional dynamics, including the merging of same-sign vortices and the interaction with the mutually induced strain, as well as three-dimensional displacement and core instabilities resulting from this interaction. Flows subject to combined instabilities are also considered, in particular the impingement of opposite-sign vortices on a ground plane. We emphasize the physical mechanisms responsible for the flow phenomena and clearly present the key results that are useful to the reader for predicting the dynamics and instabilities of parallel vortices.

  16. Bosonic topological phase in a paired superfluid

    NASA Astrophysics Data System (ADS)

    Gazit, Snir; Vishwanath, Ashvin

    2016-03-01

    We study an effective model of two interacting species of bosons in two dimensions, which is amenable to sign problem free Monte Carlo simulations. In addition to conventional ground states, we access a paired superfluid which is also a topological phase, protected by the remaining U (1 ) ×Z2 symmetry. This phase arises from the condensation of a composite object, the bound state of vortices and antivortices of one species, to a boson of the second species. We introduce a bulk response function, the Ising analog of the quantized Hall effect, to diagnose the topological phase. The interplay of broken symmetry and topology leads to interesting effects such as fractionally charged vortices in the paired superfluid. Possible extensions towards realistic models of cold atomic bosons are discussed.

  17. Resonant tunneling of fluctuation Cooper pairs

    DOE PAGESBeta

    Galda, Alexey; Mel'nikov, A. S.; Vinokur, V. M.

    2015-02-09

    Superconducting fluctuations have proved to be an irreplaceable source of information about microscopic and macroscopic material parameters that could be inferred from the experiment. According to common wisdom, the effect of thermodynamic fluctuations in the vicinity of the superconducting transition temperature, Tc, is to round off all of the sharp corners and discontinuities, which otherwise would have been expected to occur at Tc. Here we report the current spikes due to radiation-induced resonant tunneling of fluctuation Cooper pairs between two superconductors which grow even sharper and more pronounced upon approach to Tc. This striking effect offers an unprecedented tool formore » direct measurements of fluctuation Cooper pair lifetime, which is key to our understanding of the fluctuation regime, most notably to nature of the pseudogap state in high-temperature superconductors. Our finding marks a radical departure from the conventional view of superconducting fluctuations as a blurring and rounding phenomenon.« less

  18. Pair Crystallization in the Pseudogap State

    NASA Astrophysics Data System (ADS)

    Chen, Han-Dong; Vafek, Oskar; Yazdani, Ali; Zhang, Shou-Cheng

    2004-03-01

    Recent STM experiments of BiSrCaCuO have shown evidence of real-space organization of electronic states in the pseudogap state[1]. In this talk, we argue based on symmetry considerations as well as model calculations that the experimentally observed ordering is due to organization of d-wave hole pairs into a static lattice, similar to those previously proposed in the vicinity of vortices[2]. In addition to these results, we also make prediction on how to further distinguish between a pair-crystal and more typical electronic modulations due to charge density wave ordering or those due to simple scattering from a periodic potential. [1] M. Vershinin, S. Misra, S. Ono, S. Abe, Y. Ando, and A. Yazdani, submitted. [2] H.D. Chen, J.P. Hu, S. Capponi, E. Arrigoni and S.C. Zhang, Phys. Rev. Lett., 89, 137004 (2002).

  19. Seismic interferometry with antipodal station pairs

    NASA Astrophysics Data System (ADS)

    Lin, Fan-Chi; Tsai, Victor C.

    2013-09-01

    In this study, we analyze continuous data from all Global Seismographic Network stations between year 2000 and 2009 and demonstrate that several body wave phases (e.g., PP, PcPPKP, SKSP, and PPS) propagating between nearly antipodal station pairs can be clearly observed without array stacking using the noise/coda cross-correlation method. Based on temporal correlations with global seismicity, we show that the observed body waves are clearly earthquake related. Moreover, based on single-earthquake analysis, we show that the earthquake coda energy observed between ~10,000 and 30,000 s after a large earthquake contributes the majority of the signal. We refine our method based on these observations and show that the signal can be significantly improved by selecting only earthquake coda times. With our improved processing, the PKIKP phase, which does not benefit from the focusing effect near the antipode, can now also clearly be observed for long-distance station pairs.

  20. Pair importance measures in systems analysis

    SciTech Connect

    Youngblood, R.; Xue, D.; Cho, N.

    1986-01-01

    Importance measures in systems unreliability (or unavailability) analysis provide useful information in identifying components which are critical with regard to the availability or reliability of a system. Various importance measures known in the reliability literature are defined for a single component. This paper extends previous work to define importance measures for a pair of components of the system (accident sequence, core damage frequency, or health risks as appropriate), and illustrates the usefulness of these pairwise importance measures in nuclear power plants. The pairwise importance measures are immediately applicable to risk-based evaluation of the technical specifications; in addition, pairwise importances could play an important role in systems interaction studies by highlighting pairs of events between which a coupling would be significant if it existed.

  1. A search for resonant Z pair production

    SciTech Connect

    Boveia, Antonio

    2008-12-01

    I describe a search for anomalous production of Z pairs through a new massive resonance X in 2.5-2.9 fb-1 of p$\\bar{p}$ collisions at √s = 1.96 TeV using the CDFII Detector at the Fermilab Tevatron. I reconstruct Z pairs through their decays to electrons, muons, and quarks. To achieve perhaps the most efficient lepton reconstruction ever used at CDF, I apply a thorough understanding of the detector and new reconstruction software heavily revised for this purpose. In particular, I have designed and employ new general-purpose algorithms for tracking at large η in order to increase muon acceptance. Upon analyzing the unblinded signal samples, I observe no X → ZZ candidates and set upper limits on the production cross section using a Kaluza-Klein graviton-like acceptance.

  2. Average prime-pair counting formula

    NASA Astrophysics Data System (ADS)

    Korevaar, Jaap; Riele, Herman Te

    2010-04-01

    Taking r>0 , let π_{2r}(x) denote the number of prime pairs (p, p+2r) with p≤ x . The prime-pair conjecture of Hardy and Littlewood (1923) asserts that π_{2r}(x)˜ 2C_{2r} {li}_2(x) with an explicit constant C_{2r}>0 . There seems to be no good conjecture for the remainders ω_{2r}(x)=π_{2r}(x)- 2C_{2r} {li}_2(x) that corresponds to Riemann's formula for π(x)-{li}(x) . However, there is a heuristic approximate formula for averages of the remainders ω_{2r}(x) which is supported by numerical results.

  3. Extra-pair paternity in waved albatrosses.

    PubMed

    Huyvaert, K P; Anderson, D J; Jones, T C; Duan, W; Parker, P G

    2000-09-01

    We estimated the rate of extra-pair fertilizations (EPFs) in waved albatrosses (Phoebastria irrorata) on Isla Española, Galápagos, Ecuador, using multilocus minisatellite DNA fingerprinting. Waved albatrosses are socially monogamous, long-lived seabirds whose main population is on Española. Aggressive extra-pair copulation (EPC) attempts have been observed in the breeding colony during the days preceding egg-laying. Our genetic analyses of 16 families (single chicks and their attending parents) revealed evidence of EPFs in four families. In all cases males were the excluded parent. These data suggest that waved albatrosses have an unusually high rate of EPF relative to taxa with similar life histories. Future behavioural observations will determine the extent to which forced vs. unforced EPCs contribute to this high EPF rate. PMID:10972780

  4. Higher in vitro resistance to oxidative stress in extra-pair offspring.

    PubMed

    Losdat, S; Helfenstein, F; Saladin, V; Richner, H

    2011-11-01

    Oxidative stress is considered to act as a universal physiological constraint in life-history evolution of animals. This should be of interest for extra-pair paternity behaviour, and we tested here the prediction that offspring arising from extra-pair matings of female great tits show higher resistance to oxidative stress than within-pair offspring. Resistance to oxidative stress, measured as the whole blood resistance to a controlled free-radical attack, was significantly higher for extra-pair offspring as predicted although these were not heavier or in better body condition than within-pair offspring. Since resistance to oxidative stress has been suggested to enhance survival and reproductive rates, extra-pair offspring with superior resistance to oxidative stress, be it through maternal effects or paternal inheritance, may achieve higher fitness and thus provide significant indirect fitness benefits to their mothers. In addition, because oxidative stress affects colour signals and sperm traits, females may also gain fitness benefits by producing sons that are more attractive (sexy-sons hypothesis) and have sperm of superior quality (sexy-sperm hypothesis). Heritability of resistance to oxidative stress as well as maternal effects may both act as proximate mechanisms for the observed result. Disentangling these two mechanisms would require an experimental approach. Future long-term studies should also aim at experimentally testing whether higher resistance to oxidative stress of EP nestlings indeed translates into fitness benefits to females. PMID:21899636

  5. Can disordered radical pair systems provide a basis for a magnetic compass in animals?

    PubMed Central

    Hill, Erin; Ritz, Thorsten

    2010-01-01

    A proposed mechanism for magnetic compasses in animals is that systems of radical pairs transduce magnetic field information to the nervous system. One can show that perfectly ordered arrays of radical pairs are sensitive to the direction of the external magnetic field and can thus operate, in principle, as a magnetic compass. Here, we investigate how disorder, inherent in biological cells, affects the ability of radical pair systems to provide directional information. We consider biologically inspired geometrical arrangements of ensembles of radical pairs with increasing amounts of disorder and calculate the effect of changing the direction of the external magnetic field on the rate of chemical signal production by radical pair systems. Using a previously established signal transduction model, we estimate the minimum number of receptors necessary to allow for detection of the change in chemical signal owing to changes in magnetic field direction. We quantify the required increase in the number of receptors to compensate for the signal attenuation through increased disorder. We find radical-pair-based compass systems to be relatively robust against disorder, suggesting several scenarios as to how a compass structure can be realized in a biological cell. PMID:19906676

  6. Cognitive Functioning in Affected Sibling Pairs with ADHD: Familial Clustering and Dopamine Genes

    ERIC Educational Resources Information Center

    Loo, Sandra K.; Rich, Erika Carpenter; Ishii, Janeen; McGough, James; McCracken, James; Nelson, Stanley; Smalley, Susan L.

    2008-01-01

    Background: This paper examines familiality and candidate gene associations of cognitive measures as potential endophenotypes in attention-deficit/hyperactivity disorder (ADHD). Methods: The sample consists of 540 participants, aged 6 to 18, who were diagnosed with ADHD from 251 families recruited for a larger genetic study of ADHD. All members of…

  7. Strong pairing approximation in comparison with the exact solutions to the pairing Hamiltonian

    NASA Astrophysics Data System (ADS)

    Lunyov, A. V.; Mikhajlov, V. M.

    2016-01-01

    Results of the Strong Pairing Approximation (SPA) as a method with the exact particle number conservation are compared with those of the quasiparticle method (QM). It is shown that SPA comes to the same equations as QM for the gap parameter, chemical potential and one- and two-quasiparticle states. Calculations are performed for 14864Gd84 as an example, and compared with the exact solutions to the pairing Hamiltonian.

  8. Spectroscopy by frequency-entangled photon pairs

    SciTech Connect

    Yabushita, Atsushi; Kobayashi, Takayoshi

    2004-01-01

    Quantum spectroscopy was performed using the frequency-entangled broadband photon pairs generated by spontaneous parametric down-conversion. An absorptive sample was placed in front of the idler photon detector, and the frequency of signal photons was resolved by a diffraction grating. The absorption spectrum of the sample was measured by counting the coincidences, and the result is in agreement with the one measured by a conventional spectrophotometer with a classical light source.

  9. Modulational instabilities in relativistic pair plasmas

    NASA Astrophysics Data System (ADS)

    Mendonça, J. T.

    2016-05-01

    We study the modulational instability of an intense photon beam in a relativistic pair plasma. We use the wave-kinetic description of the photon field and relativistic fluid equations for electrons and positrons. This allows us to consider the influence of the photon spectral distribution and photon recoil effects on the instability threshold and growth rates. The case of very low frequencies modulations, well below plasma frequency, is compared to that of high-frequency modulations corresponding to the plasmon decay instability.

  10. On the pairing effects in triaxial nuclei

    SciTech Connect

    Oudih, M. R.; Fellah, M.; Allal, N. H.

    2014-03-05

    Triaxial deformation effect on the pairing correlations is studied in the framework of the Skyrme Hartree-Fock-Bogoliubov theory. Quantities such as binding energy, gap parameter and particle-number fluctuation are considered in neutron-rich Mo isotopes. The results are compared with those of axially symmetric calculation and with available experimental data. The role played by the particle-number projection is outlined.

  11. Signature scheme based on bilinear pairs

    NASA Astrophysics Data System (ADS)

    Tong, Rui Y.; Geng, Yong J.

    2013-03-01

    An identity-based signature scheme is proposed by using bilinear pairs technology. The scheme uses user's identity information as public key such as email address, IP address, telephone number so that it erases the cost of forming and managing public key infrastructure and avoids the problem of user private generating center generating forgery signature by using CL-PKC framework to generate user's private key.

  12. Trident Pair Production in Strong Laser Pulses

    SciTech Connect

    Ilderton, Anton

    2011-01-14

    We calculate the trident pair production amplitude in a strong laser background. We allow for finite pulse durations, while still treating the laser fields nonperturbatively in strong-field QED. Our approach reveals explicitly the individual contributions of the one-step and two-step processes. We also expose the role gauge invariance plays in the amplitudes and discuss the relation between our results and the optical theorem.

  13. Radio structures in QSO-galaxy pairs

    NASA Technical Reports Server (NTRS)

    Akujor, Chidi E.

    1990-01-01

    It is now generally agreed that if quasars and nearby low redshift galaxies are associated, then there should be luminous connections between them. However, most of the observational evidence being presented is in the optical domain, whereas such evidence should also exist at radio frequencies. The author is, therefore, investigating some quasar-galaxy pairs at radio frequencies to search for luminous connections and other structural peculiarities. Radio maps of some of these sources are presented.

  14. Neutrino-pair bremsstrahlung in a neutron star crust

    NASA Astrophysics Data System (ADS)

    Ofengeim, D. D.; Kaminker, A. D.; Yakovlev, D. G.

    2014-11-01

    Based on the formalism by Kaminker et al. (Astron. Astrophys., 343 (1999) 1009) we derive an analytic approximation for neutrino-pair bremsstrahlung emissivity due to scattering of electrons by atomic nuclei in a neutron star crust of any realistic composition. The emissivity is expressed through the generalized Coulomb logarithm which we fit by introducing an effective potential of electron-nucleus scattering. In addition, we study the conditions at which the neutrino bremsstrahlung in the crust is affected by strong magnetic fields. The results can be applied for modelling of many phenomena in neutron stars, such as thermal relaxation in young isolated neutron stars and in accreting neutron stars with overheated crust in soft X-ray transients.

  15. Population of the giant pairing vibration

    NASA Astrophysics Data System (ADS)

    Laskin, M.; Casten, R. F.; Macchiavelli, A. O.; Clark, R. M.; Bucurescu, D.

    2016-03-01

    Background: The giant pairing vibration (GPV), a correlated two-nucleon mode in the second shell above the Fermi surface, has long been predicted and expected to be strongly populated in two-nucleon transfer cross sections similar to those of the normal pairing vibration. Recent experiments have provided evidence for this mode in ,15C14 but, despite sensitive studies, it has not been definitively identified in either Sn or Pb nuclei where pairing correlations are known to play a crucial role. Purpose: Our aim is to test whether features inherent to the mixing of bound and unbound levels might account for this and to study the effect in a simple and intuitively clear approach. Method: We study the mixing of unbound levels in a set of toy models that capture the essential physics of the GPV, along with a more realistic calculation including distorted-wave Born approximation transfer amplitudes. Results: The calculated (relative) cross section to populate a simulated GPV state is effectively low, compared to the case of bound levels with no widths Conclusions: The mixing turns out to be only a minor contributor to the weak population. Rather, the main reason is the melting of the GPV peak due to the width it acquires from the low orbital angular momentum single-particle states playing a dominant role in two-nucleon transfer amplitudes. This effect, in addition to a severe Q -value mismatch, may account for the elusive nature of this mode in (t ,p ) and (p ,t ) reactions.

  16. Grandmothering life histories and human pair bonding

    PubMed Central

    Coxworth, James E.; Kim, Peter S.; McQueen, John S.; Hawkes, Kristen

    2015-01-01

    The evolution of distinctively human life history and social organization is generally attributed to paternal provisioning based on pair bonds. Here we develop an alternative argument that connects the evolution of human pair bonds to the male-biased mating sex ratios that accompanied the evolution of human life history. We simulate an agent-based model of the grandmother hypothesis, compare simulated sex ratios to data on great apes and human hunter–gatherers, and note associations between a preponderance of males and mate guarding across taxa. Then we explore a recent model that highlights the importance of mating sex ratios for differences between birds and mammals and conclude that lessons for human evolution cannot ignore mammalian reproductive constraints. In contradiction to our claim that male-biased sex ratios are characteristically human, female-biased ratios are reported in some populations. We consider the likelihood that fertile men are undercounted and conclude that the mate-guarding hypothesis for human pair bonds gains strength from explicit links with our grandmothering life history. PMID:26351687

  17. Pairing in half-filled Landau level

    SciTech Connect

    Wang, Zhiqiang; Mandal, Ipsita; Chung, Suk Bum; Chakravarty, Sudip

    2014-12-15

    Pairing of composite fermions in half-filled Landau level state is reexamined by solving the BCS gap equation with full frequency dependent current–current interactions. Our results show that there can be a continuous transition from the Halperin–Lee–Read state to a chiral odd angular momentum Cooper pair state for short-range contact interaction. This is at odds with the previously established conclusion of first order pairing transition, in which the low frequency effective interaction was assumed for the entire frequency range. We find that even if the low frequency effective interaction is repulsive, it is compensated by the high frequency regime, which is attractive. We construct the phase diagrams and show that ℓ=1 angular momentum channel is quite different from higher angular momenta ℓ≥3. Remarkably, the full frequency dependent analysis applied to the bilayer Hall system with a total filling fraction ν=1/2 +1/2 is quantitatively changed from the previously established results but not qualitatively.

  18. Persistent Ion Pairing in Aqueous Hydrochloric Acid

    SciTech Connect

    Baer, Marcel D.; Fulton, John L.; Balasubramanian, Mahalingam; Schenter, Gregory K.; Mundy, Christopher J.

    2014-07-03

    For strong acids, like hydrochloric acid, the complete dissociation into an excess proton and conjugated base as well as the formation of independent solvated charged fragments is assumed. The existence of a chloride-Hyronium (Cl-H3O+) contact ion pairs even in moderate concentration hydrochloric acid (2.5 m) demonstrates that the counter ions do not behave merely as spectators. Through the use of modern extended X-ray absorption fine structure (EXAFS) measurements in conjunction with state-of-the-art density functional theory (DFT) simulations, we are able to obtain an unprecedented view into the molecular structure of medium to high concentrated electrolytes. Here we report that the Cl-H3O+ contact ion pair structure persists throughout the entire concentration range studied and that these structures differ significantly from moieties studied in micro-solvated hydrochloric acid clusters. Characterizing distinct populations of these ion pairs gives rise to a novel molecular level description of how to think about the activity of the proton that impacts our picture of the pH scale. Funding for CJM, GKS, and JLF was provided by DOE Office of Science, Office of Basic Energy Science, Division of Chemical Sciences, Geosciences, and Biosciences. Funding for MDB was provided throught the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MB was funded through Argonne National Laboratory.

  19. Grandmothering life histories and human pair bonding.

    PubMed

    Coxworth, James E; Kim, Peter S; McQueen, John S; Hawkes, Kristen

    2015-09-22

    The evolution of distinctively human life history and social organization is generally attributed to paternal provisioning based on pair bonds. Here we develop an alternative argument that connects the evolution of human pair bonds to the male-biased mating sex ratios that accompanied the evolution of human life history. We simulate an agent-based model of the grandmother hypothesis, compare simulated sex ratios to data on great apes and human hunter-gatherers, and note associations between a preponderance of males and mate guarding across taxa. Then we explore a recent model that highlights the importance of mating sex ratios for differences between birds and mammals and conclude that lessons for human evolution cannot ignore mammalian reproductive constraints. In contradiction to our claim that male-biased sex ratios are characteristically human, female-biased ratios are reported in some populations. We consider the likelihood that fertile men are undercounted and conclude that the mate-guarding hypothesis for human pair bonds gains strength from explicit links with our grandmothering life history. PMID:26351687

  20. Cooper pairing in non-Fermi liquids

    NASA Astrophysics Data System (ADS)

    Metlitski, Max A.; Mross, David F.; Sachdev, Subir; Senthil, T.

    2015-03-01

    States of matter with a sharp Fermi surface but no well-defined Landau quasiparticles arise in a number of physical systems. Examples include (i) quantum critical points associated with the onset of order in metals; (ii) spinon Fermi-surface [U(1) spin-liquid] state of a Mott insulator; (iii) Halperin-Lee-Read composite fermion charge liquid state of a half-filled Landau level. In this work, we use renormalization group techniques to investigate possible instabilities of such non-Fermi liquids in two spatial dimensions to Cooper pairing. We consider the Ising-nematic quantum critical point as an example of an ordering phase transition in a metal, and demonstrate that the attractive interaction mediated by the order-parameter fluctuations always leads to a superconducting instability. Moreover, in the regime where our calculation is controlled, superconductivity preempts the destruction of electronic quasiparticles. On the other hand, the spinon Fermi surface and the Halperin-Lee-Read states are stable against Cooper pairing for a sufficiently weak attractive short-range interaction; however, once the strength of attraction exceeds a critical value, pairing sets in. We describe the ensuing quantum phase transition between (i) U(1 ) and Z2 spin-liquid states; (ii) Halperin-Lee-Read and Moore-Read states.

  1. Further Analysis of a Cooper Pair Insulator

    NASA Astrophysics Data System (ADS)

    Hollen, S. M.; Nguyen, H. Q.; Stewart, M. D., Jr.; Shainline, J.; Jin, Aijun; Xu, J. M.; Valles, J. M., Jr.

    2010-03-01

    Amorphous thin films of Bi deposited on a substrate with a Nano-Honeycomb (NHC) array of holes can exhibit a Cooper Pair Insulator (CPI) phase [1]. The transport in this state is dominated by the incoherent tunneling of Cooper Pairs between localized states. The resistivity is activated in temperature, and the magnetoresistance (MR) near the thickness-tuned Superconductor-Insulator Transition (SIT) exhibits a giant peak, as is found in thin films of InOx and TiN. In an effort to learn how the localization of pairs develops, we have investigated films deposited on substrates with different hole radii, order in the hole arrays, and surface roughness. We will present our latest findings on the common features describing the CPI phase, and how the above variations influence its properties and those of the thickness-tuned SIT in these amorphous films. [1] M. D. Stewart Jr., A. Yin, J. M. Xu, and J. M. Valles Jr., Science 318, 1273 (2007).

  2. Paired and interacting galaxies: Conference summary

    NASA Technical Reports Server (NTRS)

    Norman, Colin A.

    1990-01-01

    The author gives a summary of the conference proceedings. The conference began with the presentation of the basic data sets on pairs, groups, and interacting galaxies with the latter being further discussed with respect to both global properties and properties of the galactic nuclei. Then followed the theory, modelling and interpretation using analytic techniques, simulations and general modelling for spirals and ellipticals, starbursts and active galactic nuclei. Before the conference the author wrote down the three questions concerning pairs, groups and interacting galaxies that he hoped would be answered at the meeting: (1) How do they form, including the role of initial conditions, the importance of subclustering, the evolution of groups to compact groups, and the fate of compact groups; (2) How do they evolve, including issues such as relevant timescales, the role of halos and the problem of overmerging, the triggering and enhancement of star formation and activity in the galactic nuclei, and the relative importance of dwarf versus giant encounters; and (3) Are they important, including the frequency of pairs and interactions, whether merging and interactions are very important aspects of the life of a normal galaxy at formation, during its evolution, in forming bars, shells, rings, bulges, etc., and in the formation and evolution of active galaxies? Where possible he focuses on these three central issues in the summary.

  3. Interaction of a skewed Rankine vortex pair

    NASA Astrophysics Data System (ADS)

    Jayavel, S.; Patil, Pratish P.; Tiwari, Shaligram

    2008-08-01

    An analytical investigation is carried out to study the kinematics of a fluid particle in an interacting field of a skewed pair of fixed Rankine vortices. A general formulation governing the kinematics of a fluid particle has been presented based on the superposition of the velocity field due to each vortex in the pair. The kinematics of a Lagrangian fluid particle is found to be governed by a nonlinear dynamical system. The fixed or stationary points of the dynamical system have been identified analytically and their existence is confirmed by the nature of particle paths in the neighborhood of fixed points. The nature of the particle path and velocity signal is reported for general as well as special configurations of the vortex pair in the presence and absence of an external uniform flow. As a specific application of the proposed problem, superimposition of the translational velocity on a semi-infinite field of longitudinal vortices generated by vortex generators mounted on fin plates of heat exchangers has also been studied.

  4. Banach Algebras Associated to Lax Pairs

    NASA Astrophysics Data System (ADS)

    Glazebrook, James F.

    2015-04-01

    Lax pairs featuring in the theory of integrable systems are known to be constructed from a commutative algebra of formal pseudodifferential operators known as the Burchnall- Chaundy algebra. Such pairs induce the well known KP flows on a restricted infinite-dimensional Grassmannian. The latter can be exhibited as a Banach homogeneous space constructed from a Banach *-algebra. It is shown that this commutative algebra of operators generating Lax pairs can be associated with a commutative C*-subalgebra in the C*-norm completion of the *-algebra. In relationship to the Bose-Fermi correspondence and the theory of vertex operators, this C*-algebra has an association with the CAR algebra of operators as represented on Fermionic Fock space by the Gelfand-Naimark-Segal construction. Instrumental is the Plücker embedding of the restricted Grassmannian into the projective space of the associated Hilbert space. The related Baker and tau-functions provide a connection between these two C*-algebras, following which their respective state spaces and Jordan-Lie-Banach algebras structures can be compared.

  5. Pairing Correlations with Single Cooper Pair Transfer to Individual Quantal States

    NASA Astrophysics Data System (ADS)

    Potel, G.; Broglia, R. A.

    2013-01-01

    Making use of the fact that the collective modes associated with the spontaneous (static and dynamic) violation of gauge invariance in atomic nuclei (pairing rotations and pairing vibrations) are amenable to a simple, quite accurate nuclear structure description (BCS and QRPA respectively), it is possible to quantitatively test the reaction mechanism which is at the basis of two-nucleon transfer reactions, specific probe of pairing in nuclei. With the help of the static and dynamic mean field spectroscopic amplitudes, taking into account successive and simultaneous transfer channels properly corrected because of non-orthogonality effects, as well as describing the associated elastic channels in terms of experimentally determined optical potentials, one obtains absolute, two-particle transfer differential cross sections which provide an overall account of the data within experimental errors. One of the first results connected with such quantitative studies of pairing correlations in nuclei is the observation of phonon mediated pairing in the exotic halo nucleus 11Li, and the associated discovery of a new mechanism to break nuclear gauge symmetry: bootstrap, pigmy-resonance-mediated Cooper pair binding.

  6. Base Pair Opening in a Deoxynucleotide Duplex Containing a cis-syn Thymine Cyclobutane Dimer Lesion

    PubMed Central

    Wenke, Belinda B.; Huiting, Leah N.; Frankel, Elisa B.; Lane, Benjamin F.; Núñez, Megan E.

    2014-01-01

    The cis-syn thymine cyclobutane dimer is a DNA photoproduct implicated in skin cancer. We compared the stability of individual base pairs in thymine dimer-containing duplexes to undamaged parent 10-mer duplexes. UV melting thermodynamic measurements, CD spectroscopy, and 2D NOESY NMR spectroscopy confirm that the thymine dimer lesion is locally and moderately destabilizing within an overall B-form duplex conformation. We measured the rates of exchange of individual imino protons by NMR using magnetization transfer from water and determined the equilibrium constant for the opening of each base pair Kop. In the normal duplex Kop decreases from the frayed ends of the duplex toward the center, such that the central TA pair is the most stable with a Kop of 8×10−7. In contrast, base pair opening at the 5’T of the thymine dimer is facile. The 5’T of the dimer has the largest equilibrium constant (Kop =3×10−4) in its duplex, considerably larger than even the frayed penultimate base pairs. Notably, base pairing by the 3’T of the dimer is much more stable than by the 5’T, indicating that the predominant opening mechanism for the thymine dimer lesion is not likely to be flipping out into solution as a single unit. The dimer asymmetrically affects the stability of the duplex in its vicinity, destabilizing base pairing on its 5’ side more than on the 3’ side. The striking differences in base pair opening between parent and dimer duplexes occur independently of the duplex-single strand melting transitions. PMID:24328089

  7. Isoalloxazine derivatives promote photocleavage of natural RNAs at G.U base pairs embedded within helices.

    PubMed Central

    Burgstaller, P; Hermann, T; Huber, C; Westhof, E; Famulok, M

    1997-01-01

    We have recently shown that isoalloxazine derivatives are able to photocleave RNA specifically at G.U base pairs embedded within a helical stack. The reaction involves the selective molecular recognition of G.U base pairs by the isoalloxazine ring and the removal of one nucleoside downstream of the uracil residue. Divalent metal ions are absolutely required for cleavage. Here we extend our studies to complex natural RNA molecules with known secondary and tertiary structures, such as tRNAs and a group I intron (td). G.U pairs were cleaved in accordance with the phylogenetically and experimentally derived secondary and tertiary structures. Tandem G.U pairs or certain G.U pairs located at a helix extremity were not affected. These new cleavage data, together with the RNA crystal structure, allowed us to perform molecular dynamics simulations to provide a structural basis for the observed specificity. We present a stable structural model for the ternary complex of the G. U-containing helical stack, the isoalloxazine molecule and a metal ion. This model provides significant new insight into several aspects of the cleavage phenomenon, mechanism and specificity for G. U pairs. Our study shows that in large natural RNAs a secondary structure motif made of an unusual base pair can be recognized and cleaved with high specificity by a low molecular weight molecule. This photocleavage reaction thus opens up the possibility of probing the accessibility of G.U base pairs, which are endowed with specific structural and functional roles in numerous structured and catalytic RNAs and interactions of RNA with proteins, in folded RNAs. PMID:9321652

  8. Alignment and Integration Techniques for Mirror Segment Pairs on the Constellation X Telescope

    NASA Technical Reports Server (NTRS)

    Hadjimichael, Theo; Lehan, John; Olsen, Larry; Owens, Scott; Saha, Timo; Wallace, Tom; Zhang, Will

    2007-01-01

    We present the concepts behind current alignment and integration techniques for testing a Constellation-X primary-secondary mirror segment pair in an x-ray beam line test. We examine the effects of a passive mount on thin glass x-ray mirror segments, and the issues of mount shape and environment on alignment. We also investigate how bonding and transfer to a permanent housing affects the quality of the final image, comparing predicted results to a full x-ray test on a primary secondary pair.

  9. Morphology transformation in pairs of galaxies - the local sample

    NASA Astrophysics Data System (ADS)

    Junqueira, S.; de Mello, D. F.; Infante, L.

    1998-04-01

    We present photometric analysis of a local sample of 14 isolated pairs of galaxies. The photometric properties analyzed in the local pairs are: colors, morphology, tidal effects and activity. We verify that close pairs have an excess of early-type galaxies and many elliptical galaxies in this pairs are, in fact, lenticular galaxies. Many late-pairs in our sample show strong tidal damage and blue star formation regions. We conclude that pairs of different morphologies may have passed through different evolution processes which violently transformed their morphology. Pairs with at least one early-type component may be descendents of groups of galaxies. However, late-type pairs are probably long-lived showing clearly signs of interaction. Some of them could be seen as an early stage of mergers. These photometric databases will be used for future comparison with more distant pairs in order to study galaxy evolution.

  10. Older Galaxy Pair Has Surprisingly Youthful Glow

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Poster Version

    A pair of interacting galaxies might be experiencing the galactic equivalent of a mid-life crisis. For some reason, the pair, called Arp 82, didn't make their stars early on as is typical of most galaxies. Instead, they got a second wind later in life -- about 2 billion years ago -- and started pumping out waves of new stars as if they were young again.

    Arp 82 is an interacting pair of galaxies with a strong bridge and a long tail. NGC 2535 is the big galaxy and NGC 2536 is its smaller companion. The disk of the main galaxy looks like an eye, with a bright 'pupil' in the center and oval-shaped 'eyelids.' Dramatic 'beads on a string' features are visible as chains of evenly spaced star-formation complexes along the eyelids. These are presumably the result of large-scale gaseous shocks from a grazing encounter. The colors of this galaxy indicate that the observed stars are young to intermediate in age, around 2 million to 2 billion years old, much less than the age of the universe (13.7 billion years).

    The puzzle is: why didn't Arp 82 form many stars earlier, like most galaxies of that mass range? Scientifically, it is an oddball and provides a relatively nearby lab for studying the age of intermediate-mass galaxies.

    This picture is a composite captured by Spitzer's infrared array camera with light at wavelength 8 microns shown in red, NASA's Galaxy Evolution Explorer combined 1530 and 2310 Angstroms shown in blue, and the Southeastern Association for Research in Astronomy Observatory light at 6940 Angstroms shown in green.

  11. Series-Coupled Pairs of Silica Microresonators

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Iltchenko, Vladimir; Maleki, Lute; Handley, Tim

    2009-01-01

    Series-coupled pairs of whispering-gallery-mode optical microresonators have been demonstrated as prototypes of stable, narrow-band-pass photonic filters. Characteristics that are generally considered desirable in a photonic or other narrow-band-pass filter include response as nearly flat as possible across the pass band, sharp roll-off, and high rejection of signals outside the pass band. A single microresonator exhibits a Lorentzian filter function: its peak response cannot be made flatter and its roll-off cannot be made sharper. However, as a matter of basic principle applicable to resonators in general, it is possible to (1) use multiple resonators, operating in series or parallel, to obtain a roll-off sharper, and out-of-band rejection greater, relative to those of a Lorentzian filter function and (2) to make the peak response (the response within the pass band) flatter by tuning the resonators to slightly different resonance frequencies that span the pass band. The first of the two microresonators in each series-coupled pair was a microtorus made of germania-doped silica (containing about 19 mole percent germania), which is a material used for the cores of some optical fibers. The reasons for choosing this material is that exposing it to ultraviolet light causes it to undergo a chemical change that changes its index of refraction and thereby changes the resonance frequency. Hence, this material affords the means to effect the desired slight relative detuning of the two resonators. The second microresonator in each pair was a microsphere of pure silica. The advantage of making one of the resonators a torus instead of a sphere is that its spectrum of whispering-gallery-mode resonances is sparser, as needed to obtain a frequency separation of at least 100 GHz between resonances of the filter as a whole.

  12. Matched molecular pair analysis in drug discovery.

    PubMed

    Dossetter, Alexander G; Griffen, Edward J; Leach, Andrew G

    2013-08-01

    Multiple parameter optimisation in drug discovery is difficult, but Matched Molecular Pair Analysis (MMPA) can help. Computer algorithms can process data in an unbiased way to yield design rules and suggest better molecules, cutting the number of design cycles. The approach often makes more suggestions than can be processed manually and methods to deal with this are proposed. However, there is a paucity of contextually specific design rules, which would truly make the technique powerful. By combining extracted information from multiple sources there is an opportunity to solve this problem and advance medicinal chemistry in a matter of months rather than years. PMID:23557664

  13. Generalized magnetofluid connections in pair plasmas

    SciTech Connect

    Asenjo, Felipe A.; Comisso, Luca; Mahajan, Swadesh M.

    2015-12-15

    We extend the magnetic connection theorem of ideal magnetohydrodynamics to nonideal relativistic pair plasmas. Adopting a generalized Ohm's law, we prove the existence of generalized magnetofluid connections that are preserved by the plasma dynamics. We show that these connections are related to a general antisymmetric tensor that unifies the electromagnetic and fluid fields. The generalized magnetofluid connections set important constraints on the plasma dynamics by forbidding transitions between configurations with different magnetofluid connectivity. An approximated solution is explicitly shown where the corrections due to current inertial effects are found.

  14. Thermalization of pair plasma with proton loading

    SciTech Connect

    Aksenov, A. G.

    2009-05-03

    We study kinetic evolution of nonequilibrium optically thick electron-positron plasma towards thermal equilibrium solving numerically relativistic Boltzmann equations with energy per particle ranging from 0.1 to 10 MeV. We generalize our results presented in [1], considering proton loading of the pair plasma. Proton loading introduces new characteristic timescales essentially due to proton-proton and proton-electron Coulomb collisions. Taking into account not only binary but also triple direct and inverse interactions between electrons, positrons, photons and protons we show that thermal equilibrium is reached on a timescale t{sub th}{approx_equal}10{sup -11} sec.

  15. Relativistic thermal plasmas - Pair processes and equilibria

    NASA Technical Reports Server (NTRS)

    Lightman, A. P.

    1982-01-01

    The work of Bisnovatyi-Kogan, Zel'dovich and Sunyaev (1971) is extended and generalized, through the inclusion of pair-producing photon processes and effects due to the finite size of the plasma, in an investigation of the equilibria of relativistic thermal plasmas which takes into account electron-positron creation and annihilation and photons produced within the plasma. It is shown that the bridge between an effectively thin plasma and an effectively thick plasma occurs in the transrelativistic region, where the dimensionless temperature value is between 0.1 and 1.0 and the temperature remains in this region over a great luminosity range.

  16. A biometric signcryption scheme without bilinear pairing

    NASA Astrophysics Data System (ADS)

    Wang, Mingwen; Ren, Zhiyuan; Cai, Jun; Zheng, Wentao

    2013-03-01

    How to apply the entropy in biometrics into the encryption and remote authentication schemes to simplify the management of keys is a hot research area. Utilizing Dodis's fuzzy extractor method and Liu's original signcryption scheme, a biometric identity based signcryption scheme is proposed in this paper. The proposed scheme is more efficient than most of the previous proposed biometric signcryption schemes for that it does not need bilinear pairing computation and modular exponentiation computation which is time consuming largely. The analysis results show that under the CDH and DL hard problem assumption, the proposed scheme has the features of confidentiality and unforgeability simultaneously.

  17. Resonant pairing between fermions with unequal masses

    SciTech Connect

    Wu, Shin-Tza; Pao, C.-H.; Yip, S.-K.

    2006-12-01

    We study via mean-field theory the pairing between fermions of different masses, especially at the unitary limit. At equal populations, the thermodynamic properties are identical with the equal mass case provided an appropriate rescaling is made. At unequal populations, for sufficiently light majority species, the system does not phase separate. For sufficiently heavy majority species, the phase separated normal phase have a density larger than that of the superfluid. For atoms in harmonic traps, the density profiles for unequal mass fermions can be drastically different from their equal-mass counterparts.

  18. Generalized magnetofluid connections in pair plasmas

    NASA Astrophysics Data System (ADS)

    Asenjo, Felipe A.; Comisso, Luca; Mahajan, Swadesh M.

    2015-12-01

    We extend the magnetic connection theorem of ideal magnetohydrodynamics to nonideal relativistic pair plasmas. Adopting a generalized Ohm's law, we prove the existence of generalized magnetofluid connections that are preserved by the plasma dynamics. We show that these connections are related to a general antisymmetric tensor that unifies the electromagnetic and fluid fields. The generalized magnetofluid connections set important constraints on the plasma dynamics by forbidding transitions between configurations with different magnetofluid connectivity. An approximated solution is explicitly shown where the corrections due to current inertial effects are found.

  19. Mated Fingerprint Card Pairs 2 (MFCP2)

    National Institute of Standards and Technology Data Gateway

    NIST Mated Fingerprint Card Pairs 2 (MFCP2) (PC database for purchase)   NIST Special Database 14 is being distributed for use in development and testing of automated fingerprint classification and matching systems on a set of images which approximate a natural horizontal distribution of the National Crime Information Center (NCIC) fingerprint classes. A newer version of the compression/decompression software on the CDROM can be found at the website http://www.nist.gov/itl/iad/ig/nigos.cfm as part of the NBIS package.

  20. Method for sequencing DNA base pairs

    DOEpatents

    Sessler, Andrew M.; Dawson, John

    1993-01-01

    The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source.

  1. Self-Injurious Behavior and Fragile X Syndrome: Findings from the National Fragile X Survey

    ERIC Educational Resources Information Center

    Symons, Frank J.; Byiers, Breanne J.; Raspa, Melissa; Bishop, Ellen; Bailey, Donald B., Jr.

    2010-01-01

    We used National Fragile X Survey data in order to examine reported self-injurious behavior (SIB) to (a) generate lifetime and point prevalence estimates, (b) document detailed features of SIB (frequency, types, location, severity) in relation to gender, and (c) compare comorbid conditions between matched pairs (SIB vs. no SIB). Results indicate…

  2. Quantifying inbreeding avoidance through extra-pair reproduction

    PubMed Central

    Reid, Jane M; Arcese, Peter; Keller, Lukas F; Germain, Ryan R; Duthie, A Bradley; Losdat, Sylvain; Wolak, Matthew E; Nietlisbach, Pirmin

    2015-01-01

    Extra-pair reproduction is widely hypothesized to allow females to avoid inbreeding with related socially paired males. Consequently, numerous field studies have tested the key predictions that extra-pair offspring are less inbred than females’ alternative within-pair offspring, and that the probability of extra-pair reproduction increases with a female's relatedness to her socially paired male. However, such studies rarely measure inbreeding or relatedness sufficiently precisely to detect subtle effects, or consider biases stemming from failure to observe inbred offspring that die during early development. Analyses of multigenerational song sparrow (Melospiza melodia) pedigree data showed that most females had opportunity to increase or decrease the coefficient of inbreeding of their offspring through extra-pair reproduction with neighboring males. In practice, observed extra-pair offspring had lower inbreeding coefficients than females’ within-pair offspring on average, while the probability of extra-pair reproduction increased substantially with the coefficient of kinship between a female and her socially paired male. However, simulations showed that such effects could simply reflect bias stemming from inbreeding depression in early offspring survival. The null hypothesis that extra-pair reproduction is random with respect to kinship therefore cannot be definitively rejected in song sparrows, and existing general evidence that females avoid inbreeding through extra-pair reproduction requires reevaluation given such biases. PMID:25346331

  3. Investigating giant (Gt) repression in the formation of partially overlapping pair-rule stripes.

    PubMed

    Ribeiro, Thiago Casé; Ventrice, Glauber; Machado-Lima, Ariane; Andrioli, Luiz Paulo

    2010-11-01

    Drosophila pair-rule genes are expressed in striped patterns with a precise order of overlap between stripes of different genes. We investigated the role of Giant (Gt) in the regulation of even-skipped, hairy, runt, and fushi tarazu stripes formed in the vicinity of Gt expression domains. In gt null embryos, specific stripes of eve, h, run, and ftz are disrupted. With an ectopic expression system, we verified that stripes affected in the mutant are also repressed. Simultaneously hybridizing gt misxpressing embryos with two pair-rule gene probes, we were able to distinguish differences in the repression of pairs of stripes that overlap extensively. Together, our results showed Gt repression roles in the regulation of two groups of partially overlapping stripes and that Gt morphogen activity is part of the mechanism responsible for the differential positioning of these stripes borders. We discuss the possibility that other factors regulate Gt stripe targets as well. PMID:20925117

  4. Affective processing requires awareness.

    PubMed

    Lähteenmäki, Mikko; Hyönä, Jukka; Koivisto, Mika; Nummenmaa, Lauri

    2015-04-01

    Studies using backward masked emotional stimuli suggest that affective processing may occur outside visual awareness and imply primacy of affective over semantic processing, yet these experiments have not strictly controlled for the participants' awareness of the stimuli. Here we directly compared the primacy of affective versus semantic categorization of biologically relevant stimuli in 5 experiments (n = 178) using explicit (semantic and affective discrimination; Experiments 1-3) and implicit (semantic and affective priming; Experiments 4-5) measures. The same stimuli were used in semantic and affective tasks. Visual awareness was manipulated by varying exposure duration of the masked stimuli, and subjective level of stimulus awareness was measured after each trial using a 4-point perceptual awareness scale. When participants reported no awareness of the stimuli, semantic and affective categorization were at chance level and priming scores did not differ from zero. When participants were even partially aware of the stimuli, (a) both semantic and affective categorization could be performed above chance level with equal accuracy, (b) semantic categorization was faster than affective categorization, and (c) both semantic and affective priming were observed. Affective categorization speed was linearly dependent on semantic categorization speed, suggesting dependence of affective processing on semantic recognition. Manipulations of affective and semantic categorization tasks revealed a hierarchy of categorization operations beginning with basic-level semantic categorization and ending with superordinate level affective categorization. We conclude that both implicit and explicit affective and semantic categorization is dependent on visual awareness, and that affective recognition follows semantic categorization. PMID:25559654

  5. Synergy between pair coupled cluster doubles and pair density functional theory

    SciTech Connect

    Garza, Alejandro J.; Bulik, Ireneusz W.; Henderson, Thomas M.; Scuseria, Gustavo E.

    2015-01-28

    Pair coupled cluster doubles (pCCD) has been recently studied as a method capable of accounting for static correlation with low polynomial cost. We present three combinations of pCCD with Kohn–Sham functionals of the density and on-top pair density (the probability of finding two electrons on top of each other) to add dynamic correlation to pCCD without double counting. With a negligible increase in computational cost, these pCCD+DFT blends greatly improve upon pCCD in the description of typical problems where static and dynamic correlations are both important. We argue that—as a black-box method with low scaling, size-extensivity, size-consistency, and a simple quasidiagonal two-particle density matrix—pCCD is an excellent match for pair density functionals in this type of fusion of multireference wavefunctions with DFT.

  6. Physicochemical Properties of Ion Pairs of Biological Macromolecules

    PubMed Central

    Iwahara, Junji; Esadze, Alexandre; Zandarashvili, Levani

    2015-01-01

    Ion pairs (also known as salt bridges) of electrostatically interacting cationic and anionic moieties are important for proteins and nucleic acids to perform their function. Although numerous three-dimensional structures show ion pairs at functionally important sites of biological macromolecules and their complexes, the physicochemical properties of the ion pairs are not well understood. Crystal structures typically show a single state for each ion pair. However, recent studies have revealed the dynamic nature of the ion pairs of the biological macromolecules. Biomolecular ion pairs undergo dynamic transitions between distinct states in which the charged moieties are either in direct contact or separated by water. This dynamic behavior is reasonable in light of the fundamental concepts that were established for small ions over the last century. In this review, we introduce the physicochemical concepts relevant to the ion pairs and provide an overview of the recent advancement in biophysical research on the ion pairs of biological macromolecules. PMID:26437440

  7. Fundamental aspects of recoupled pair bonds. II. Recoupled pair bond dyads in carbon and sulfur difluoride

    SciTech Connect

    Dunning, Thom H. Takeshita, Tyler Y.; Xu, Lu T.

    2015-01-21

    Formation of a bond between a second ligand and a molecule with a recoupled pair bond results in a recoupled pair bond dyad. We examine the recoupled pair bond dyads in the a{sup 3}B{sub 1} states of CF{sub 2} and SF{sub 2}, which are formed by the addition of a fluorine atom to the a{sup 4}Σ{sup −} states of CF and SF, both of which possess recoupled pair bonds. The two dyads are very different. In SF{sub 2}, the second FS–F bond is very strong (D{sub e} = 106.3 kcal/mol), the bond length is much shorter than that in the SF(a{sup 4}Σ{sup −}) state (1.666 Å versus 1.882 Å), and the three atoms are nearly collinear (θ{sub e} = 162.7°) with only a small barrier to linearity (0.4 kcal/mol). In CF{sub 2}, the second FC–F bond is also very strong (D{sub e} = 149.5 kcal/mol), but the bond is only slightly shorter than that in the CF(a{sup 4}Σ{sup −}) state (1.314 Å versus 1.327 Å), and the molecule is strongly bent (θ{sub e} = 119.0°) with an 80.5 kcal/mol barrier to linearity. The a{sup 3}B{sub 1} states of CF{sub 2} and SF{sub 2} illustrate the fundamental differences between recoupled pair bond dyads formed from 2s and 3p lone pairs.

  8. Pair Cascades in Blazars and Radio Galaxies

    NASA Astrophysics Data System (ADS)

    Roustazadeh Sheikhyousefi, Parisa

    2012-05-01

    Recently some intermediate BL Lac objects (IBL), low frequency peak BL Lac objects (LBL) and flat spectrum radio quasars (FSRQs) were detected as very high energy gamma-ray sources (VHE; E > 100 GeV) by the Major Atmospheric Gamma-ray Imaging Cherenkov Telescope (MAGIC), the High Energy Stereoscopic System (H.E.S.S) and the Very Energetic Radiation Imaging Telescope Array System (VERITAS). These discoveries suggest that VHE gamma-rays may be produced in all types of active galactic nuclei (AGN) and that this is not only a common property of high frequency peaked BL Lac objects (HBL). The detection of the radio galaxies M87, Cen A and NGC 1275 supports this idea. In those AGN, VHE photons may interact with low energy photons from the broadline region (BLR), accretion disk around the black hole or thermal infrared photons form a dust torus by photon-photon pair production if the total center-of-momentum frame energy is above threshold to produce an electron-positron pair. These particles can produce new high energy photons by Compton up-scattering, and again these high energy photons can interact with soft photons to produce a pair of particles. This process will continue, leading to a shower (cascade) of particles and radiation. As the shower develops, it will expand laterally. This may explain the detection of the radio galaxies as VHE gamma-ray sources. The central part of my Ph.D. research work deals with the theoretical simulation of very high energy gamma-ray induced pair cascades in blazars and radio galaxies. Gamma-rays from the core of the AGN interact with low energy photons from the AGN environment and produce pairs of electrons and positrons resulting in Compton supported pair cascades. I developed a Monte Carlo code which treats the processes of gamma-gamma absorption and pair production, gamma-ray and electron/positron propagation, and Compton scattering, tracking particle trajectories in full 3-dimensional geometry. I showed that even for a very weak

  9. The cavity-embedded-cooper pair transistor

    NASA Astrophysics Data System (ADS)

    Chen, Fei

    Nearly eight decades after Erwin Schrodinger proposed his famous cat paradox, the boundary between classical and quantum physics is becoming accessible to experimental study in condensed matter systems, in which macroscopic and microscopic degrees of freedom interact with each other. The cavity-embedded-Cooper pair transistor (cCPT) is an ideal candidate for such a study in that it is not only strongly and intrinsically nonlinear but also fully quantum mechanical. A novel technique, based on the circuit quantum electrodynamics architecture, is first introduced for applying a dc bias to a high-Q superconducting microwave cavity. The development and investigation of the cCPT system, in which a Cooper pair transistor acting as a single artificial atom is directly coupled to an on-chip dc-biased high-Q resonator, is then presented. Self-oscillations in the cCPT, internally driven by the ac Josephson effect, demonstrate the strong and phase coherent coupling between matter and light in the cCPT. Meanwhile, photons continually produced by the system are collected and characterized by quantum state tomography, which indicates the non-classical nature of the emitted light and the nonlinear quantum dynamics of the cCPT system.

  10. Generalized quantum interference of correlated photon pairs

    PubMed Central

    Kim, Heonoh; Lee, Sang Min; Moon, Han Seb

    2015-01-01

    Superposition and indistinguishablility between probability amplitudes have played an essential role in observing quantum interference effects of correlated photons. The Hong-Ou-Mandel interference and interferences of the path-entangled photon number state are of special interest in the field of quantum information technologies. However, a fully generalized two-photon quantum interferometric scheme accounting for the Hong-Ou-Mandel scheme and path-entangled photon number states has not yet been proposed. Here we report the experimental demonstrations of the generalized two-photon interferometry with both the interferometric properties of the Hong-Ou-Mandel effect and the fully unfolded version of the path-entangled photon number state using photon-pair sources, which are independently generated by spontaneous parametric down-conversion. Our experimental scheme explains two-photon interference fringes revealing single- and two-photon coherence properties in a single interferometer setup. Using the proposed interferometric measurement, it is possible to directly estimate the joint spectral intensity of a photon pair source. PMID:25951143

  11. Odd frequency pairing of interacting Majorana fermions

    NASA Astrophysics Data System (ADS)

    Huang, Zhoushen; Woelfle, Peter; Balatsky, Alexandar

    Majorana fermions are rising as a promising key component in quantum computation. While the prevalent approach is to use a quadratic (i.e. non-interacting) Majorana Hamiltonian, when expressed in terms of Dirac fermions, generically the Hamiltonian involves interaction terms. Here we focus on the possible pair correlations in a simple model system. We study a model of Majorana fermions coupled to a boson mode and show that the anomalous correlator between different Majorana fermions, located at opposite ends of a topological wire, exhibits odd frequency behavior. It is stabilized when the coupling strength g is above a critical value gc. We use both, conventional diagrammatic theory and a functional integral approach, to derive the gap equation, the critical temperature, the gap function, the critical coupling, and a Ginzburg-Landau theory allowing to discuss a possible subleading admixture of even-frequency pairing. Work supported by USDOE DE-AC52-06NA25396 E304, Knut and Alice Wallenberg Foundation, and ERC DM-321031.

  12. Cooperative interactions between paired domain and homeodomain.

    PubMed

    Jun, S; Desplan, C

    1996-09-01

    The Pax proteins are a family of transcriptional regulators involved in many developmental processes in all higher eukaryotes. They are characterized by the presence of a paired domain (PD), a bipartite DNA binding domain composed of two helix-turn-helix (HTH) motifs,the PAI and RED domains. The PD is also often associated with a homeodomain (HD) which is itself able to form homo- and hetero-dimers on DNA. Many of these proteins therefore contain three HTH motifs each able to recognize DNA. However, all PDs recognize highly related DNA sequences, and most HDs also recognize almost identical sites. We show here that different Pax proteins use multiple combinations of their HTHs to recognize several types of target sites. For instance, the Drosophila Paired protein can bind, in vitro, exclusively through its PAI domain, or through a dimer of its HD, or through cooperative interaction between PAI domain and HD. However, prd function in vivo requires the synergistic action of both the PAI domain and the HD. Pax proteins with only a PD appear to require both PAI and RED domains, while a Pax-6 isoform and a new Pax protein, Lune, may rely on the RED domain and HD. We propose a model by which Pax proteins recognize different target genes in vivo through various combinations of their DNA binding domains, thus expanding their recognition repertoire. PMID:8787739

  13. Cooper pair splitting in isolated NSN island

    NASA Astrophysics Data System (ADS)

    Tai, Pochen; Sun, Chia-Heng; Jiang, Jheng-An; Wu, Cen-Shawn; Chen, Jeng-Chung; Chen, Yung-Fu

    2014-03-01

    Cooper pair is in a maximally entangled two-particle state, and may have applications on solid state version of quantum teleportation. We investigate Cooper pair splitting, a charge-transfer process by crossed Andreev reflection (CAR), in a three-island system. The system consists of one superconducting island (S) and two normal-metal islands (N), while S connects to two N via two tunnel junctions. When the charging energy of the system is the dominant energy factor, this system is suitable to study charge transfers down to single-electron regime. Two single-electron transistors as charge sensors are capacitively coupled to two N, respectively, to observe charge tunneling events. Several competing charge-transfer processes as long with CAR also occur in two S/N interfaces, such as quasi-particle tunneling, cotunneling, and ordinary Andreev reflection. Correlation measurements of charge fluctuation at two S/N interfaces should help to tell CAR process apart from other competing processes.

  14. Convective Polymer Depletion on Pair Particle Interactions

    NASA Astrophysics Data System (ADS)

    Fan, Tai-Hsi; Taniguchi, Takashi; Tuinier, Remco

    2011-11-01

    Understanding transport, reaction, aggregation, and viscoelastic properties of colloid-polymer mixture is of great importance in food, biomedical, and pharmaceutical sciences. In non-adsorbing polymer solutions, colloidal particles tend to aggregate due to the depletion-induced osmotic or entropic force. Our early development for the relative mobility of pair particles assumed that polymer reorganization around the particles is much faster than particle's diffusive time, so that the coupling of diffusive and convective effects can be neglected. Here we present a nonequilibrium two-fluid (polymer and solvent) model to resolve the convective depletion effect. The theoretical framework is based on ground state approximation and accounts for the coupling of fluid flow and polymer transport to better describe pair particle interactions. The momentum and polymer transport, chemical potential, and local viscosity and osmotic pressure are simultaneously solved by numerical approximation. This investigation is essential for predicting the demixing kinetics in the pairwise regime for colloid-polymer mixtures. This work is supported by NSF CMMI 0952646.

  15. ``Schooling'' of wing pairs in flapping flight

    NASA Astrophysics Data System (ADS)

    Ramananarivo, Sophie; Zhang, Jun; Ristroph, Leif; AML, Courant Collaboration; Physics NYU Collaboration

    2015-11-01

    The experimental setup implements two independent flapping wings swimming in tandem. Both are driven with the same prescribed vertical heaving motion, but the horizontal motion is free, which means that the swimmers can take up any relative position and forward speed. Experiments show however clearly coordinated motions, where the pair of wings `crystallize' into specific stable arrangements. The follower wing locks into the path of the leader, adopting its speed, and with a separation distance that takes on one of several discrete values. By systematically varying the kinematics and wing size, we show that the set of stable spacings is dictated by the wavelength of the periodic wake structure. The forces maintaining the pair cohesion are characterized by applying an external force to the follower to perturb it away from the `stable wells'. These results show that hydrodynamics alone is sufficient to induce cohesive and coordinated collective locomotion through a fluid, and we discuss the hypothesis that fish schools and bird flocks also represent stable modes of motion.

  16. Kidney paired donation: principles, protocols and programs.

    PubMed

    Ferrari, Paolo; Weimar, Willem; Johnson, Rachel J; Lim, Wai H; Tinckam, Kathryn J

    2015-08-01

    Due to the ongoing shortage of deceased-donor organs, novel strategies to augment kidney transplantation rates through expanded living donation strategies have become essential. These include desensitization in antibody-incompatible transplants and kidney paired donation (KPD) programs. KPD enables kidney transplant candidates with willing but incompatible living donors to join a registry of other incompatible pairs in order to find potentially compatible transplant solutions. Given the significant immunologic barriers with fewer donor options, single-center or small KPD programs may be less successful in transplanting the more sensitized patients; the optimal solution for the difficult-to-match patient is access to more potential donors and large multicenter or national registries are essential. Multicenter KPD programs have become common in the last decade, and now represent one of the most promising opportunities to improve transplant rates. To maximize donor-recipient matching, and minimize immunologic risk, these multicenter KPD programs use sophisticated algorithms to identify optimal match potential, with simultaneous two-, three- or more complex multiway exchanges. The article focuses on the recent progresses in KPD and it also reviews some of the differences and commonalities across four different national KPD programs. PMID:25294848

  17. On magnetic pair production above fast pulsar polar caps

    NASA Technical Reports Server (NTRS)

    An, S.

    1985-01-01

    Magnetic pair production is one of high-energy electromagnetic conversion processes important to the development of pair-photon cascades in pulsars. On the basis of current polar cap models, the properties of magnetic pair production in fast pulsars are discussed. Suppose there is a roughly dipole magnetic field at the stellar surface, the author estimate the effects on non-zero curvature of magnetic field lines upon curvature radiation from primary particles and pair production rate near the surface of pulsars.

  18. PLASMA EFFECTS ON FAST PAIR BEAMS. II. REACTIVE VERSUS KINETIC INSTABILITY OF PARALLEL ELECTROSTATIC WAVES

    SciTech Connect

    Schlickeiser, R.; Krakau, S.; Supsar, M. E-mail: steffen.krakau@rub.de

    2013-11-01

    The interaction of TeV gamma-rays from distant blazars with the extragalactic background light produces relativistic electron-positron pair beams by the photon-photon annihilation process. Using the linear instability analysis in the kinetic limit, which properly accounts for the longitudinal and the small but finite perpendicular momentum spread in the pair momentum distribution function, the growth rate of parallel propagating electrostatic oscillations in the intergalactic medium is calculated. Contrary to the claims of Miniati and Elyiv, we find that neither the longitudinal nor the perpendicular spread in the relativistic pair distribution function significantly affect the electrostatic growth rates. The maximum kinetic growth rate for no perpendicular spread is even about an order of magnitude greater than the corresponding reactive maximum growth rate. The reduction factors in the maximum growth rate due to the finite perpendicular spread in the pair distribution function are tiny and always less than 10{sup –4}. We confirm earlier conclusions by Broderick et al. and our group that the created pair beam distribution function is quickly unstable in the unmagnetized intergalactic medium. Therefore, there is no need to require the existence of small intergalactic magnetic fields to scatter the produced pairs, so that the explanation (made by several authors) for the Fermi non-detection of the inverse Compton scattered GeV gamma-rays by a finite deflecting intergalactic magnetic field is not necessary. In particular, the various derived lower bounds for the intergalactic magnetic fields are invalid due to the pair beam instability argument.

  19. A Paired Membrane Umbrella Double Lumen Cannula Assures Consistent Cavopulmonary Assistance in a Fontan Sheep Model

    PubMed Central

    Wang, Dongfang; Gao, Guodong; Plunkett, Mark; Zhao, Guangfeng; Topaz, Stephen; Ballard-Croft, Cherry; Zwischenberger, Joseph B.

    2014-01-01

    Objective The AvalonElite™ double lumen cannula (DLC) can provide effective cavopulmonary assistance (CPA) in a Fontan (TCPC) sheep model, but it requires strict alignment. The objective was to fabricate and test a newly designed paired umbrellas DLC without alignment requirement. Methods The paired membrane umbrellas were designed on the DLC to bracket infusion blood flow toward the pulmonary artery. Two umbrellas were attached, one 4 cm above and one 4 cm below infusion opening. Umbrellas were temporarily wrapped and glued to DLC body to facilitate insertion. A TCPC mock loop was used to test CPA performance and reliability with DLC rotation and displacement. The paired umbrella DLC was also tested in a TCPC adult sheep model (n=6). Results The bench test showed up to 4.5 l/min pumping flow and about 90% pumping flow efficiency at 360° rotation and 8 cm displacement of DLC. The TCPC model with compromised hemodynamics was successfully created in all 6 sheep. The CPA DLC with paired umbrellas was smoothly inserted into SVC and extracardiac conduit in all sheep. At 3.5–4.0 l/min pump flow, the sABP and CVP returned to normal baseline and remained stable throughout 90 min experiment, demonstrating effective CPA support. DLC Rotation and displacement did not affect performance. Autopsy revealed well opened and positioned paired umbrellas, and DLCs were easily removed from RJV. Conclusions Our DLC with paired umbrellas is easy to insert and remove. The paired umbrellas eliminated the strict alignment requirement and assured consistent CPA performance. (245 Words) PMID:24930609

  20. Using Pair Programming to Teach CAD Based Engineering Graphics

    ERIC Educational Resources Information Center

    Leland, Robert P.

    2010-01-01

    Pair programming was introduced into a course in engineering graphics that emphasizes solid modeling using SolidWorks. In pair programming, two students work at a single computer, and periodically trade off roles as driver (hands on the keyboard and mouse) and navigator (discuss strategy and design issues). Pair programming was used in a design…

  1. Pair-Programming Helps Female Computer Science Students

    ERIC Educational Resources Information Center

    Werner, Linda L.; Hanks, Brian; McDowell, Charlie

    2004-01-01

    Pair-programming has been found to be very beneficial in educational settings. Students who pair in their introductory programming course are more confident, have greater course completion and pass rates, and are more likely to persist in computer-related majors. Although pairing helps all students, we believe that it is particularly beneficial…

  2. Nearest-neighbor parameters for 7-deaza-adenosine·uridine base pairs in RNA duplexes.

    PubMed

    Richardson, Katherine E; Znosko, Brent M

    2016-06-01

    One of the major limitations in RNA structure prediction is the lack of information about the effect of nonstandard nucleotides on stability. The nonstandard nucleotide 7-deaza-adenosine (7DA) is a naturally occurring analog of adenosine that has been studied for medicinal purposes and is commonly referred to as tubercidin. In 7DA, the nitrogen in the 7 position of adenosine is replaced by a carbon. Differences in RNA duplex stability due to the removal of this nitrogen can be attributed to a possible change in hydration and a difference in base stacking interactions resulting from changes in the electrostatics of the ring. In order to determine how 7DA affects the stability of RNA, optical melting experiments were conducted on RNA duplexes that contain either internal or terminal 7DA·U pairs with all possible nearest-neighbor combinations. On average, duplexes containing 7DA·U pairs are 0.43 and 0.07 kcal/mol less stable than what is predicted for the same duplex containing internal and terminal A-U pairs, respectively. Thermodynamic parameters for all nearest-neighbor combinations of 7DA·U pairs were derived from the data. These parameters can be used to more accurately predict the secondary structure and stability of RNA duplexes containing 7DA·U pairs. PMID:27099368

  3. Pair production and annihilation in strong magnetic fields. [of neutron stars and pulsars

    NASA Technical Reports Server (NTRS)

    Daugherty, J. K.; Harding, A. K.

    1983-01-01

    Electromagnetic phenomena occurring in the presence of strong magnetic fields are currently of great interest in high-energy astrophysics. In particular, the process of pair production by single photons in the presence of fields of order 10 to the 12th power Gauss is of importance in cascade models of pulsar gamma ray emission, and may also become significant in theories of other radiation phenomena whose sources may be neutron stars (e.g., gamma ray bursts). In addition to pair production, the inverse process of pair annihilation is greatly affected by the presence of superstrong magnetic fields. The most significant departures from annihilation processes in free space are a reduction in the total rate for annihilation into two photons, a broadening of the familiar 511-keV line for annihilation at rest, and the possibility for annihilation into a single photon which dominates the two-photon annihilation for B (10 to 13th power Gauss) The physics of these pair conversion processes, which is reviewed briefly, can become quite complex in the teragauss regime, and can involve calculations which are technically difficult to incorporate into models of emission mechanisms in neutron star magnetospheres. However, theoretical work, especially the case of pair annihilation, also suggests potential techniques for more direct measurements of field strengths near the stellar surface.

  4. Effect of Short-Term Pair Housing of Juvenile Rhesus Macaques (Macaca mulatta) on Immunologic Parameters

    PubMed Central

    Benton, Carrie G; West, Michael W; Hall, Shane M; Marko, Shannon T; Johnson, Joshua C

    2013-01-01

    Social housing of nonhuman primates (NHP) in an infectious disease setting presents unique challenges, and individual housing is often scientifically justified. At our institute, we recognized an opportunity to limit individual housing to the minimal period necessary by pair-housing NHP after quarantine and separating them just before they are moved into holding rooms for infectious disease studies. To alleviate concerns that pair-housing followed by separation affects the immune system of NHP and makes them unfit as research candidates, we designed a short-term pair-housing study. After a 3-wk baseline period, juvenile rhesus macaques (age, 3 to 4 y) were paired for 7 wk and then separated for 7 wk. During the study, serum cortisol, lymphocyte subsets, and proinflammatory cytokines were measured. The average values for all parameters were significantly lower after separation than during the baseline period. We conclude that short-term pair housing is a viable option at our institute for social housing of NHP. PMID:23849405

  5. Statistics of Simulated and Observed Pair Separations in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Beron-Vera, Francisco J.; LaCasce, J. H.

    2016-07-01

    Pair-separation statistics of in-situ and synthetic surface drifters deployed near the \\emph{Deepwater Horizon} site in the Gulf of Mexico are investigated. The synthetic trajectories derive from a 1-km-resolution data-assimilative Navy Coastal Ocean Model (NCOM) simulation. The in-situ drifters were launched in the Grand LAgrangian Deployment (GLAD). Diverse measures of the dispersion are calculated and compared to theoretical predictions. For the NCOM pairs, the measures indicate nonlocal pair dispersion at the smallest sampled scales. At separations exceeding 100 km, pair motion is uncorrelated, indicating absolute rather than relative dispersion. With the GLAD drifters however the statistics suggest local dispersion (in which pair separations exhibit power law growth), in line with previous findings. The disagreement stems in part from inertial oscillations, which affect the energy levels at small scales without greatly altering the net particle displacements. They were significant in GLAD but much weaker in the NCOM simulations. In addition the GLAD drifters were launched close together, producing few independent realizations and hence weaker statistical significance. Restricting the NCOM set to those launched at the same locations yields very similar statistics.

  6. Screening for Multiple Genes Influencing Dyslexia.

    ERIC Educational Resources Information Center

    Smith, Shelley D.; And Others

    1991-01-01

    Examines the "sib pair" method of linkage analysis designed to locate genes influencing dyslexia, which has several advantages over the "LOD" score method. Notes that the sib pair analysis was able to detect the same linkages as the LOD method, plus a possible third region. Confirms that the sib pair method is an effective means of screening. (RS)

  7. Modeling the initial conditions of interacting galaxy pairs using Identikit

    NASA Astrophysics Data System (ADS)

    Mortazavi, S. Alireza; Lotz, Jennifer M.; Barnes, Joshua E.; Snyder, Gregory F.

    2016-01-01

    We develop and test an automated technique to model the dynamics of interacting galaxy pairs. We use Identikit as a tool for modelling and matching the morphology and kinematics of the interacting pairs of equal-mass galaxies. In order to reduce the effect of subjective human judgement, we automate the selection of phase space regions used to match simulations to data, and we explore how selection of these regions affects the random uncertainties of parameters in the best-fitting model. In this work, we use an independent set of GADGET SPH simulations as input data to determine the systematic bias in the measured encounter parameters based on the known initial conditions of these simulations. We test both cold gas and young stellar components in the GADGET simulations to explore the effect of choosing H I versus H α as the line-of-sight velocity tracer. We find that we can group the results into tests with good, fair, and poor convergence based on the distribution of parameters of models close to the best-fitting model. For tests with good and fair convergence, we rule out large fractions of parameter space and recover merger stage, eccentricity, pericentric distance, viewing angle, and initial disc orientations within 3σ of the correct value. All of tests on prograde-prograde systems have either good or fair convergence. The results of tests on edge-on discs are less biased than face-on tests. Retrograde and polar systems do not converge and may require constraints from regions other than the tidal tails and bridges.

  8. Aluminium Diphosphamethanides: Hidden Frustrated Lewis Pairs.

    PubMed

    Styra, Steffen; Radius, Michael; Moos, Eric; Bihlmeier, Angela; Breher, Frank

    2016-07-01

    The synthesis and characterisation of two aluminium diphosphamethanide complexes, [Al(tBu)2 {κ(2) P,P'-Mes*PCHPMes*}] (3) and [Al(C6 F5 )2 {κ(2) P,P'-Mes*PCHPMes*}] (4), and the silylated analogue, Mes*PCHP(SiMe3 )Mes* (5), are reported. The aluminium complexes feature four-membered PCPAl core structures consisting of diphosphaallyl ligands. The silylated phosphine 5 was found to be a valuable precursor for the synthesis of 4 as it cleanly reacts with the diaryl aluminium chloride [(C6 F5 )2 AlCl]2 . The aluminium complex 3 reacts with molecular dihydrogen at room temperature under formation of the acyclic σ(2) λ(3) ,σ(3) λ(3) -diphosphine Mes*PCHP(H)Mes* and the corresponding dialkyl aluminium hydride [tBu2 AlH]3 . Thus, 3 belongs to the family of so-called hidden frustrated Lewis pairs. PMID:27271936

  9. Hydrodynamics of pairs of interacting cytoskeletal filaments

    NASA Astrophysics Data System (ADS)

    Shinar, Tamar; Shelley, Michael

    2011-11-01

    Pairwise filament interactions underlie the dynamics of complex cytoskeletal networks in cells. These networks in turn play a crucial role in many cellular processes such as formation of the mitotic spindle and cell cleavage in cytokinesis. We model interactions of pairs of filaments immersed in a viscous, fluidic environment. The filaments are modeled using a slender body approximation, capturing their indirect interactions mediated by the immersing fluid. Direct filament interactions via molecular motors complexes induce alignment and parallel or anti-parallel sliding. The motor proteins are modeled as simple spring-like structures that walk directionally toward one end of the filament. We examine the resulting stresses in the fluid to better understand how the microscopic interactions lead to bulk behavior of cytoskeletal networks.

  10. Base pair analogs in the gas phase.

    PubMed

    Roscioli, Joseph R; Pratt, David W

    2003-11-25

    A rotationally resolved electronic spectrum of the gas-phase dimer 2-aminopyridine.2-pyridone, an analog of the adenine.thymine base pair, has been observed and assigned, leading to precise measurements of its moments of inertia and preliminary determinations of its structure. A Watson-Crick configuration results, with N...H-N and N-H...O hydrogen bond lengths of 2.898 and 2.810 A, respectively. The two bases are found not to be coplanar; a dihedral angle of 6.1 degrees between the base planes is also estimated from the measured moments of inertia. Possible chemical and biological implications of these results are discussed. PMID:14612563

  11. Formylborane formation with frustrated Lewis pair templates.

    PubMed

    Sajid, Muhammad; Kehr, Gerald; Daniliuc, Constantin G; Erker, Gerhard

    2014-01-20

    Boranes R2 BH react with carbon monoxide by forming the respective borane carbonyl compounds R2 BH(CO). The formation of (C6 F5 )2 BH(CO) derived from the Piers borane, HB(C6 F5 )2 , is a typical example. Subsequent CO-hydroboration does not take place, since the formation of the formylborane is usually endothermic. However, an "η(2) -formylborane" was formed by CO-hydroboration with the Piers borane at vicinal phosphane/borane frustrated Lewis pair (FLP) templates. Subsequent treatment with pyridine liberated the intact formylborane from the FLP framework, and (pyridine)(C6 F5 )2 BCHO was then isolated as a stable compound. This product underwent typical reactions of carbonyl compounds, such as Wittig olefination. PMID:24338931

  12. Method for sequencing DNA base pairs

    DOEpatents

    Sessler, A.M.; Dawson, J.

    1993-12-14

    The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source. 6 figures.

  13. The stratospheric arrival pair in infrasound propagation.

    PubMed

    Waxler, Roger; Evers, Läslo G; Assink, Jelle; Blom, Phillip

    2015-04-01

    The ideal case of a deep and well-formed stratospheric duct for long range infrasound propagation in the absence of tropospheric ducting is considered. A canonical form, that of a pair of arrivals, for ground returns of impulsive signals in a stratospheric duct is determined. The canonical form is derived from the geometrical acoustics approximation, and is validated and extended through full wave modeling. The full caustic structure of the field of ray paths is found and used to determine phase relations between the contributions to the wavetrain from different propagation paths. Finally, comparison with data collected from the 2005 fuel gas depot explosion in Buncefield, England is made. The correspondence between the theoretical results and the observations is shown to be quite good. PMID:25920837

  14. Electroweak boson pair production at the Tevatron

    SciTech Connect

    Errede, S.M.

    1994-12-01

    Preliminary results from CDF and D{O} on W{gamma}, Z{gamma} and WW, WZ, ZZ boson pair production in {radical}s = 1.8 TeV {anti p}-p collisions from the 1992--93 collider run are presented. Direct limits on CP-conserving and CP-violating WW{gamma}, WWZ, ZZ{gamma} and Z{gamma}{gamma} anomalous couplings have been obtained. The results are consistent with Standard Model expectations. In the static limit, the direct experimental limits on WW{gamma} and ZZ{gamma} anomalous couplings are related to bounds on the higher-order static (transition) EM moments of the W(Z) bosons. Expectations from the on-going and future Tevatron collider runs are discussed.

  15. NMR analysis of base-pair opening kinetics in DNA

    PubMed Central

    Szulik, Marta W.; Voehler, Markus; Stone, Michael P.

    2014-01-01

    Base pairing in nucleic acids plays a crucial role in their structure and function. Differences in the base pair opening and closing kinetics of individual double stranded DNA sequences or between chemically modified base pairs provide insight into the recognition of these base pairs by DNA processing enzymes. This unit describes how to quantify the kinetics for localized base pairs by observing changes in the imino proton signals by nuclear magnetic resonance spectroscopy. The determination of all relevant parameters using state of the art techniques and NMR instrumentation, including cryoprobes, is discussed. PMID:25501592

  16. Electron-positron pair equilibrium in strongly magnetized plasmas

    SciTech Connect

    Harding, A.K.

    1984-11-01

    Steady states of thermal electron-positron pair plasmas at mildly relativistic temperatures and in strong magnetic fields are investigated. The pair density in steady-state equilibrium, where pair production balances annihilation, is found as a function of temperature, magnetic field strength and source size, by a numerical calculation which includes pair production attenuation and Compton scattering of the photons. It is found that there is a maximum pair density for each value of temperature and field strength, and also a source size above which optically thin equilibrium states do not exist. (ESA)

  17. Scheduler for multiprocessor system switch with selective pairing

    DOEpatents

    Gara, Alan; Gschwind, Michael Karl; Salapura, Valentina

    2015-01-06

    System, method and computer program product for scheduling threads in a multiprocessing system with selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). The method configures the selective pairing facility to use checking provide one highly reliable thread for high-reliability and allocate threads to corresponding processor cores indicating need for hardware checking. The method configures the selective pairing facility to provide multiple independent cores and allocate threads to corresponding processor cores indicating inherent resilience.

  18. Demographic mechanisms of inbreeding adjustment through extra-pair reproduction

    PubMed Central

    Reid, Jane M; Duthie, A Bradley; Wolak, Matthew E; Arcese, Peter; van de Pol, Martijn

    2015-01-01

    One hypothesis explaining extra-pair reproduction is that socially monogamous females mate with extra-pair males to adjust the coefficient of inbreeding (f) of extra-pair offspring (EPO) relative to that of within-pair offspring (WPO) they would produce with their socially paired male. Such adjustment of offspring f requires non-random extra-pair reproduction with respect to relatedness, which is in turn often assumed to require some mechanism of explicit pre-copulatory or post-copulatory kin discrimination. We propose three demographic processes that could potentially cause mean f to differ between individual females’ EPO and WPO given random extra-pair reproduction with available males without necessarily requiring explicit kin discrimination. Specifically, such a difference could arise if social pairings formed non-randomly with respect to relatedness or persisted non-randomly with respect to relatedness, or if the distribution of relatedness between females and their sets of potential mates changed during the period through which social pairings persisted. We used comprehensive pedigree and pairing data from free-living song sparrows (Melospiza melodia) to quantify these three processes and hence investigate how individual females could adjust mean offspring f through instantaneously random extra-pair reproduction. Female song sparrows tended to form social pairings with unrelated or distantly related males slightly less frequently than expected given random pairing within the defined set of available males. Furthermore, social pairings between more closely related mates tended to be more likely to persist across years than social pairings between less closely related mates. However, these effects were small and the mean relatedness between females and their sets of potential extra-pair males did not change substantially across the years through which social pairings persisted. Our framework and analyses illustrate how demographic and social structuring

  19. Stability and size of particle pairs in complex plasmas

    SciTech Connect

    Nosenko, V.; Ivlev, A. V.; Kompaneets, R.; Morfill, G.

    2014-11-15

    Particle pairing in a complex plasma was experimentally studied with the emphasis on pair spatial extent and stability. Micron-size particles were suspended in the (pre)sheath area above the lower electrode in a capacitively coupled radio-frequency discharge in argon. They formed vertical pairs due to the ion wakes created by the flow of ions past particles. We discuss the confinement mechanism for the lower particle, resulting from a combination of the wake field and the field of non-uniform sheath. A model of particle pairs is proposed, which provides good description for the dependence of pair size and stability on experimental parameters.

  20. Dynamical Creation of Bosonic Cooper-Like Pairs

    SciTech Connect

    Keilmann, Tassilo; Garcia-Ripoll, Juan Jose

    2008-03-21

    We propose a scheme to create a metastable state of paired bosonic atoms in an optical lattice. The most salient features of this state are that the wave function of each pair is a Bell state and that the pair size spans half the lattice, similar to fermionic Cooper pairs. This mesoscopic state can be created with a dynamical process that involves crossing a quantum phase transition and which is supported by the symmetries of the physical system. We characterize the final state by means of a measurable two-particle correlator that detects both the presence of the pairs and their size.

  1. Superluminal Sweeping Spot Pair Events in Astronomical Settings

    NASA Astrophysics Data System (ADS)

    Nemiroff, Robert J.

    2015-01-01

    Sweeping beams of light can cast spots that move superluminally across scattering surfaces. Such faster-than-light speeds are well-known phenomena that do not violate special relativity. It is shown that under certain circumstances, superluminal spot pair creation and annihilation events can occur that provide unique information to observers. These spot pair events are not particle pair events -- they are the sudden creation or annihilation of a pair of relatively illuminated spots on a scattering surface. Astronomical settings where superluminal spot pairs might be found include Earth's Moon, passing asteroids, pulsars, and variable nebula. Potentially recoverable information includes three dimensional imaging, relative geometric size factors, and distances.

  2. Nebular spectra of pair-instability supernovae

    NASA Astrophysics Data System (ADS)

    Jerkstrand, A.; Smartt, S. J.; Heger, A.

    2016-01-01

    If very massive stars (M ≳ 100 M⊙) can form and avoid too strong mass-loss during their evolution, they are predicted to explode as pair-instability supernovae (PISNe). One critical test for candidate events is whether their nucleosynthesis yields and internal ejecta structure, being revealed through nebular-phase spectra at t ≳ 1 yr, match those of model predictions. Here, we compute theoretical spectra based on model PISN ejecta at 1-3 yr post-explosion to allow quantitative comparison with observations. The high column densities of PISNe lead to complete gamma-ray trapping for t ≳ 2 yr which, combined with fulfilled conditions of steady state, leads to bolometric supernova luminosities matching the 56Co decay. Most of the gamma-rays are absorbed by the deep-lying iron and silicon/sulphur layers. The ionization balance shows a predominantly neutral gas state, which leads to emission lines of Fe I, Si I, and S I. For low-mass PISNe, the metal core expands slowly enough to produce a forest of distinct lines, whereas high-mass PISNe expand faster and produce more featureless spectra. Line blocking is complete below ˜5000 Å for several years, and the model spectra are red. The strongest line is typically [Ca II] λλ7291, 7323, one of few lines from ionized species. We compare our models with proposed PISN candidates SN 2007bi and PTF12dam, finding discrepancies for several key observables and thus no support for a PISN interpretation. We discuss distinct spectral features predicted by the models, and the possibility of detecting pair-instability explosions among non-superluminous supernovae.

  3. Near intron pairs and the metazoan tree.

    PubMed

    Lehmann, Jörg; Stadler, Peter F; Krauss, Veiko

    2013-03-01

    Gene structure data can substantially advance our understanding of metazoan evolution and deliver an independent approach to resolve conflicts among existing hypotheses. Here, we used changes of spliceosomal intron positions as novel phylogenetic marker to reconstruct the animal tree. This kind of data is inferred from orthologous genes containing mutually exclusive introns at pairs of sequence positions in close proximity, so-called near intron pairs (NIPs). NIP data were collected for 48 species and utilized as binary genome-level characters in maximum parsimony (MP) analyses to reconstruct deep metazoan phylogeny. All groupings that were obtained with more than 80% bootstrap support are consistent with currently supported phylogenetic hypotheses. This includes monophyletic Chordata, Vertebrata, Nematoda, Platyhelminthes and Trochozoa. Several other clades such as Deuterostomia, Protostomia, Arthropoda, Ecdysozoa, Spiralia, and Eumetazoa, however, failed to be recovered due to a few problematic taxa such as the mite Ixodesand the warty comb jelly Mnemiopsis. The corresponding unexpected branchings can be explained by the paucity of synapomorphic changes of intron positions shared between some genomes, by the sensitivity of MP analyses to long-branch attraction (LBA), and by the very unequal evolutionary rates of intron loss and intron gain during evolution of the different subclades of metazoans. In addition, we obtained an assemblage of Cnidaria, Porifera, and Placozoa as sister group of Bilateria+Ctenophora with medium support, a disputable, but remarkable result. We conclude that NIPs can be used as phylogenetic characters also within a broader phylogenetic context, given that they have emerged regularly during evolution irrespective of the large variation of intron density across metazoan genomes. PMID:23201572

  4. Nucleic acid duplexes incorporating a dissociable covalent base pair

    NASA Technical Reports Server (NTRS)

    Gao, K.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

    1999-01-01

    We have used molecular modeling techniques to design a dissociable covalently bonded base pair that can replace a Watson-Crick base pair in a nucleic acid with minimal distortion of the structure of the double helix. We introduced this base pair into a potential precursor of a nucleic acid double helix by chemical synthesis and have demonstrated efficient nonenzymatic template-directed ligation of the free hydroxyl groups of the base pair with appropriate short oligonucleotides. The nonenzymatic ligation reactions, which are characteristic of base paired nucleic acid structures, are abolished when the covalent base pair is reduced and becomes noncoplanar. This suggests that the covalent base pair linking the two strands in the duplex is compatible with a minimally distorted nucleic acid double-helical structure.

  5. Nucleic acid duplexes incorporating a dissociable covalent base pair.

    PubMed

    Gao, K; Orgel, L E

    1999-12-21

    We have used molecular modeling techniques to design a dissociable covalently bonded base pair that can replace a Watson-Crick base pair in a nucleic acid with minimal distortion of the structure of the double helix. We introduced this base pair into a potential precursor of a nucleic acid double helix by chemical synthesis and have demonstrated efficient nonenzymatic template-directed ligation of the free hydroxyl groups of the base pair with appropriate short oligonucleotides. The nonenzymatic ligation reactions, which are characteristic of base paired nucleic acid structures, are abolished when the covalent base pair is reduced and becomes noncoplanar. This suggests that the covalent base pair linking the two strands in the duplex is compatible with a minimally distorted nucleic acid double-helical structure. PMID:10611299

  6. Sequence Affects the Cyclization of DNA Minicircles.

    PubMed

    Wang, Qian; Pettitt, B Montgomery

    2016-03-17

    Understanding how the sequence of a DNA molecule affects its dynamic properties is a central problem affecting biochemistry and biotechnology. The process of cyclizing short DNA, as a critical step in molecular cloning, lacks a comprehensive picture of the kinetic process containing sequence information. We have elucidated this process by using coarse-grained simulations, enhanced sampling methods, and recent theoretical advances. We are able to identify the types and positions of structural defects during the looping process at a base-pair level. Correlations along a DNA molecule dictate critical sequence positions that can affect the looping rate. Structural defects change the bending elasticity of the DNA molecule from a harmonic to subharmonic potential with respect to bending angles. We explore the subelastic chain as a possible model in loop formation kinetics. A sequence-dependent model is developed to qualitatively predict the relative loop formation time as a function of DNA sequence. PMID:26938490

  7. Mean-field plus various types of pairing models and an exact boson mapping of the standard pairing model

    SciTech Connect

    Pan Feng; Wang Yin; Guan Xin; Jia Lu; Chen Xiangrong; Draayer, J. P.

    2011-06-28

    Exact solutions of Nilsson mean-field with various pairing interactions are reviewed. Some even-odd mass differences and moments of inertia of low-lying states for rare earth and actinide nuclei are calculated for the nearest-orbit pairing approximation as well as for the extended pairing model and compared to available experimental data. An exact boson mapping of the standard pairing Hamiltonian is also reported. Under the mapping, fermion pair operators are mapped exactly onto corresponding bosons. The image of the mapping is a Bose-Hubbard model with orbit-dependent hopping.

  8. Affective Dynamics in Psychopathology

    PubMed Central

    Trull, Timothy J.; Lane, Sean P.; Koval, Peter; Ebner-Priemer, Ulrich W.

    2016-01-01

    We discuss three varieties of affective dynamics (affective instability, emotional inertia, and emotional differentiation). In each case, we suggest how these affective dynamics should be operationalized and measured in daily life using time-intensive methods, like ecological momentary assessment or ambulatory assessment, and recommend time-sensitive analyses that take into account not only the variability but also the temporal dependency of reports. Studies that explore how these affective dynamics are associated with psychological disorders and symptoms are reviewed, and we emphasize that these affective processes are within a nexus of other components of emotion regulation.

  9. Mating strategies in dominant meerkats: evidence for extra-pair paternity in relation to genetic relatedness between pair mates.

    PubMed

    Leclaire, S; Nielsen, J F; Sharp, S P; Clutton-Brock, T H

    2013-07-01

    Rates of extra-pair paternity (EPP) have frequently been associated with genetic relatedness between social mates in socially monogamous birds. However, evidence is limited in mammals. Here, we investigate whether dominant females use divorce or extra-pair paternity as a strategy to avoid the negative effects of inbreeding when paired with a related male in meerkats Suricata suricatta, a species where inbreeding depression is evident for several traits. We show that dominant breeding pairs seldom divorce, but that rates of EPP are associated with genetic similarity between mates. Although extra-pair males are no more distantly related to the female than social males, they are more heterozygous. Nevertheless, extra-pair pups are not more heterozygous than within-pair pups. Whether females benefit from EPP in terms of increased fitness of the offspring, such as enhanced survival or growth, requires further investigations. PMID:23675879

  10. Brief Report: Autistic Traits in Twins vs. Non-Twins--A Preliminary Study

    ERIC Educational Resources Information Center

    Ho, Alexander; Todd, Richard D.; Constantino, John N.

    2005-01-01

    Previous studies have suggested that among affected sib pairs with autism there is an increase in the frequency of twins over what would be expected in comparison to the prevalence of twins in the general population. In this study we sought to determine whether "sub-threshold" autistic traits were more pronounced in twins than in non-twins. The…

  11. Electronic and optical properties of the SiB2O4 (B=Mg, Zn, and Cd) spinel oxides: An ab initio study with the Tran-Blaha-modified Becke-Johnson density functional

    NASA Astrophysics Data System (ADS)

    Allali, D.; Bouhemadou, A.; Safi, E. Muhammad Abud Al; Bin-Omran, S.; Chegaar, M.; Khenata, R.; Reshak, A. H.

    2014-06-01

    We report ab initio density functional theory calculations of the structural, electronic and optical properties of the spinel oxides SiMg2O4, SiZng2O4, and SiCd2O4 using the full-potential linearized augmented plane-wave method. The structural parameters calculated using both the local density and generalized gradient approximations to the exchange-correlation potential are consistent with the literature data. To calculate the electronic properties, the exchange-correlation potential is treated with various functionals, and we find that the newly developed Tran-Blaha-modified Becke-Johnson functional significantly improves the band gap. We predict a direct band gap in all of the considered SiB2O4 compounds, and the band gaps continuously decrease as the atomic size of the B element increases. The decrease in the fundamental direct band gap (Γ-Γ) from SiMg2O4 to SiZn2O4 to SiCd2O4 can be attributed to p-d mixing in the upper valence bands of SiZn2O4 and SiCd2O4. The lowest conduction band is well dispersive, similar to that found for transparent conducting oxides such as ZnO. This band is mainly defined by the s and p electrons of the Si and B (B=Mg, Zn, Cd) atoms. The topmost valence band is considerably less dispersive and is defined by O-2p and B-d electrons. The charge-carrier effective masses are evaluated at the topmost valence band and at the bottommost conduction band that were calculated. The frequency-dependent complex dielectric function, absorption coefficient, refractive index, extinction coefficient, reflectivity and electron energy loss function were estimated. We find that the value of the zero-frequency limit of the dielectric function ε(0) increases as the band gap decreases. The origins of the peaks and structures in the optical spectra are determined in terms of the calculated energy band structures.

  12. De novo and inherited CNVs in MZ twin pairs selected for discordance and concordance on Attention Problems

    PubMed Central

    Ehli, Erik A; Abdellaoui, Abdel; Hu, Yueshan; Hottenga, Jouke Jan; Kattenberg, Mathijs; van Beijsterveldt, Toos; Bartels, Meike; Althoff, Robert R; Xiao, Xiangjun; Scheet, Paul; de Geus, Eco J; Hudziak, James J; Boomsma, Dorret I; Davies, Gareth E

    2012-01-01

    Copy number variations (CNVs) have been reported to be causal suspects in a variety of psychopathologic traits. We investigate whether de novo and/or inherited CNVs contribute to the risk for Attention Problems (APs) in children. Based on longitudinal phenotyping, 50 concordant and discordant monozygotic (MZ) twin pairs were selected from a sample of ∼3200 MZ pairs. Two types of de novo CNVs were investigated: (1) CNVs shared by both MZ twins, but not inherited (pre-twinning de novo CNVs), which were detected by comparing copy number (CN) calls between parents and twins and (2) CNVs not shared by co-twins (post-twinning de novo CNVs), which were investigated by comparing the CN calls within MZ pairs. The association between the overall CNV burden and AP was also investigated for CNVs genome-wide, CNVs within genes and CNVs outside of genes. Two de novo CNVs were identified and validated using quantitative PCR: a pre-twinning de novo duplication in a concordant-unaffected twin pair and a post-twinning deletion in the higher scoring twin from a concordant-affected pair. For the overall CNV burden analyses, affected individuals had significantly larger CNVs that overlapped with genes than unaffected individuals (P=0.008). This study suggests that the presence of larger CNVs may increase the risk for AP, because they are more likely to affect genes, and confirms that MZ twins are not always genetically identical. PMID:22490988

  13. Mechanically Biased, Hinged Pairs of Piezoelectric Benders

    NASA Technical Reports Server (NTRS)

    Sager, Frank E.

    2005-01-01

    The upper part of the figure depicts an actuator that comprises two mechanically biased piezoelectric benders hinged together at their ends and equipped with tabs at their mid-length points for attachment to the relatively moving objects that are to be actuated. In the example of the figure, the attachment tabs are labeled to indicate that the actuator is used to drive a pump piston relative to a base plate. Actuators of this type could be used to drive low-power, small-volume pumps in consumer, medical, and aerospace applications, and to generate and measure linear displacements in such robotic applications as teleoperation and tactile feedback. Each bender is a bimorph a unitary plate that comprises an upper and a lower piezoelectric layer plus electrode layers. Benders may also be made of several layers arranged to produce the same effect at the lower operating voltages. As stated above, each bender is mechanically biased; it is fabricated to have a small permanent curvature (the bias curvature) in the absence of applied voltage. As on other bimorphs, the electrical connections on each bender are arranged so that an applied voltage of suitable polarity causes the upper layer to expand and the lower layer to contract. In this case, the net effect of applying the voltage is that the plate becomes more concave as viewed from below. Conversely, an applied voltage of the opposite polarity causes the plate to become less concave as viewed from below. The benders in a hinged pair are oriented with their bias curvatures concave inward, so that there is a bias distance between the attachment tabs. The two benders are connected electrically in parallel, with their connection polarities chosen so that an applied voltage of one polarity causes both benders to become more convex inward (more bent), while an applied voltage of the opposite polarity causes both benders to become less convex inward (less bent). An increase or decrease in bend is accompanied by an increase or

  14. Isolated galaxies, pairs, and groups of galaxies

    NASA Technical Reports Server (NTRS)

    Kuneva, I.; Kalinkov, M.

    1990-01-01

    The authors searched for isolated galaxies, pairs and groups of galaxies in the CfA survey (Huchra et al. 1983). It was assumed that the distances to galaxies are given by R = V/H sub o, where H sub o = 100 km s(exp -1) Mpc(exp -1) and R greater than 6 Mpc. The searching procedure is close to those, applied to find superclusters of galaxies (Kalinkov and Kuneva 1985, 1986). A sphere with fixed radius r (asterisk) is described around each galaxy. The mean spatial density in the sphere is m. Let G (sup 1) be any galaxy and G (sup 2) be its nearest neighbor at a distance R sub 2. If R sub 2 exceeds the 95 percent quintile in the distribution of the distances of the second neighbors, then G (sup 1) is an isolated galaxy. Let the midpoint of G (sup 1) and G (sup 2) be O sub 2 and r sub 2=R sub 2/2. For the volume V sub 2, defined with the radius r sub 2, the density D sub 2 less than k mu, the galaxy G (sup 2) is a single one and the procedure for searching for pairs and groups, beginning with this object is over and we have to pass to another object. Here the authors present the groups - isolated and nonisolated - with n greater than 3, found in the CfA survey in the Northern galactic hemisphere. The parameters used are k = 10 and r (asterisk) = 5 Mpc. Table 1 contains: (1) the group number, (2) the galaxy, nearest to the multiplet center, (3) multiplicity n, (4) the brightest galaxy if it is not listed in (2); (5) and (6) are R.A. and Dec. (1950), (7) - mean distance D in Mpc. Further there are the mean density rho (8) of the multiplet (galaxies Mpc (exp -3), (9) the density rho (asterisk) for r (asterisk) = 5 Mpc and (10) the density rho sub g for the group with its nearest neighbor. The parenthesized digits for densities in the last three columns are powers of ten.

  15. Natural versus artificial creation of base pairs in DNA: origin of nucleobases from the perspectives of unnatural base pair studies.

    PubMed

    Hirao, Ichiro; Kimoto, Michiko; Yamashige, Rie

    2012-12-18

    Since life began on Earth, the four types of bases (A, G, C, and T(U)) that form two sets of base pairs have remained unchanged as the components of nucleic acids that replicate and transfer genetic information. Throughout evolution, except for the U to T modification, the four base structures have not changed. This constancy within the genetic code raises the question of how these complicated nucleotides were generated from the molecules in a primordial soup on the early Earth. At some prebiotic stage, the complementarity of base pairs might have accelerated the generation and accumulation of nucleotides or oligonucleotides. We have no clues whether one pair of nucleobases initially appeared on the early Earth during this process or a set of two base pairs appeared simultaneously. Recently, researchers have developed new artificial pairs of nucleobases (unnatural base pairs) that function alongside the natural base pairs. Some unnatural base pairs in duplex DNA can be efficiently and faithfully amplified in a polymerase chain reaction (PCR) using thermostable DNA polymerases. The addition of unnatural base pair systems could expand the genetic alphabet of DNA, thus providing a new mechanism for the generation novel biopolymers by the site-specific incorporation of functional components into nucleic acids and proteins. Furthermore, the process of unnatural base pair development might provide clues to the origin of the natural base pairs in a primordial soup on the early Earth. In this Account, we describe the development of three representative types of unnatural base pairs that function as a third pair of nucleobases in PCR and reconsider the origin of the natural nucleic acids. As researchers developing unnatural base pairs, they use repeated "proof of concept" experiments. As researchers design new base pairs, they improve the structures that function in PCR and eliminate those that do not. We expect that this process is similar to the one functioning in the

  16. Adaptive value of same-sex pairing in Laysan albatross

    PubMed Central

    Young, Lindsay C.; VanderWerf, Eric A.

    2014-01-01

    Same-sex pairing is widespread among animals but is difficult to explain in an evolutionary context because it does not result in reproduction, and thus same-sex behaviour often is viewed as maladaptive. Here, we compare survival, fecundity and transition probabilities of female Laysan albatross in different pair types, and we show how female–female pairing could be an adaptive alternative mating strategy, albeit one that resulted in lower fitness than male–female pairing. Females in same-sex pairs produced 80% fewer chicks, had lower survival and skipped breeding more often than those in male–female pairs. Females in same-sex pairs that raised a chick sometimes acquired a male mate in the following year, but females in failed same-sex pairs never did, suggesting that males exert sexual selection by assessing female quality and relegating low-quality females into same-sex pairs. Sexual selection by males in a monomorphic, non-ornamented species is rare and suggests that reconsideration is needed of the circumstances in which alternative reproductive behaviour evolves. Given the lack of males and obligate biparental care in this species, this research demonstrates how same-sex pairing was better than not breeding and highlights how it could be an adaptive strategy under certain demographic conditions. PMID:24285198

  17. Efficient Implementation of the Pairing on Mobilephones Using BREW

    NASA Astrophysics Data System (ADS)

    Yoshitomi, Motoi; Takagi, Tsuyoshi; Kiyomoto, Shinsaku; Tanaka, Toshiaki

    Pairing based cryptosystems can accomplish novel security applications such as ID-based cryptosystems, which have not been constructed efficiently without the pairing. The processing speed of the pairing based cryptosystems is relatively slow compared with the other conventional public key cryptosystems. However, several efficient algorithms for computing the pairing have been proposed, namely Duursma-Lee algorithm and its variant ηT pairing. In this paper, we present an efficient implementation of the pairing over some mobilephones. Moreover, we compare the processing speed of the pairing with that of the other standard public key cryptosystems, i. e. RSA cryptosystem and elliptic curve cryptosystem. Indeed the processing speed of our implementation in ARM9 processors on BREW achieves under 100 milliseconds using the supersingular curve over F397. In addition, the pairing is more efficient than the other public key cryptosystems, and the pairing can be achieved enough also on BREW mobilephones. It has become efficient enough to implement security applications, such as short signature, ID-based cryptosystems or broadcast encryption, using the pairing on BREW mobilephones.

  18. Pulsar Pair Cascades in Magnetic Fields with Offset Polar Caps

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.; Muslimov, Alex G.

    2012-01-01

    Neutron star magnetic fields may have polar caps (PC) that are offset from the dipole axis, through field-line sweepback near the light cylinder or non-symmetric currents within the star. The effects of such offsets on electron-positron pair cascades are investigated, using simple models of dipole magnetic fields with small distortions that shift the PCs by different amounts or directions. Using a Monte Carlo pair cascade simulation, we explore the changes in the pair spectrum, multiplicity and energy flux across the PC, as well as the trends in pair flux and pair energy flux with spin-down luminosity, L(sub sd). We also give an estimate of the distribution of heating flux from returning positrons on the PC for different offsets. We find that even modest offsets can produce significant increases in pair multiplicity, especially for pulsars that are near or beyond the pair death lines for centered PCs, primarily because of higher accelerating fields. Pair spectra cover several decades in energy, with the spectral range of millisecond pulsars (MSPs) two orders of magnitude higher than for normal pulsars, and PC offsets allow significant extension of all spectra to lower pair energies. We find that the total PC pair luminosity L(sub pair) is proportional to L(sub sd), with L(sub pair) approximates 10(exp -3) L(sub sd) for normal pulsars and L(sub pair) approximates 10(exp -2) L(sub sd) for MSPs. Remarkably, the total PC heating luminosity for even large offsets increases by less than a factor of two, even though the PC area increases by much larger factors, because most of the heating occurs near the magnetic axis.

  19. Electron transfer of carbonylmetalate radical pairs: femtosecond visible spectroscopy of optically excited ion pairs

    SciTech Connect

    Wen, X.; Spears, K.G.; Wiederrecht, G.P.; Wasielewski, M.R.

    1997-02-01

    Charge transfer excitation at 640 nm of the cobaltocenium tetracarbonylcobaltate ion pair, [Cp{sub 2}Co{sup +}{vert_bar}Co(CO){sub 4}{sup -}], was monitored in 1,2- dichloroethane solution by femtosecond transient visible absorption spectroscopy. The absorption prepares a neutral radical pair that can undergo spontaneous back electron transfer, and which shows a double peaked spectrum with features at 760 and 815 nm at 3 ps delay time. Transient decay times of 5.8{+-}0.5 ps were measured by monitoring the decay of Co(CO){sub 4} at 757 nm and 780 nm, and these are assigned to the back electron transfer step. The ET kinetics are consistent with the previously reported rates of electron transfer that were measured for specific vibrational states by picosecond transient IR.

  20. Unconventional pairings and radial line nodes in inversion symmetry broken superconductors

    NASA Astrophysics Data System (ADS)

    Hakioğlu, T.; Günay, Mehmet

    2016-09-01

    Noncentrosymmetric superconductors (NCSs) with broken inversion symmetry can have spin-dependent order parameters (OPs) with mixed parity which can also have nodes in the pair potential as well as the energy spectra. These nodes are distinct features that are not present in conventional superconductors. They appear as points or lines in the momentum space where the latter can have angular or radial geometries dictated by the dimensionality, the lattice structure and the pairing interaction. In this work we study the nodes in time reversal symmetry (TRS) preserving NCSs at the OP, the pair potential, and the energy spectrum levels. Nodes are examined by using spin independent pairing interactions respecting the rotational C∞v symmetry in the presence of spin-orbit coupling (SOC). The pairing symmetries and the nodal topology are affected by the relative strength of the pairing channels which is studied for the mixed singlet-triplet, pure singlet, and pure triplet. Complementary to the angular line nodes widely present in the literature, the C∞v symmetry here allows radial line nodes (RLNs) due to the nonlinear momentum dependence in the OPs. The topology of the RLNs in the mixed case shows a distinctly different characterization than the half-spin quantum vortex at the Dirac point. We apply this NCS physics to the inversion symmetry broken exciton condensates (ECs) in double quantum wells where the point and the RLNs can be found. On the other hand, for a pure triplet condensate, two fully gapped and topologically distinct regimes exist, separated by a QSHI-like zero energy superconducting state with even number of Majorana modes. We also remark on how the point and the RLNs can be manipulated, enabling an external control on the topology.