Modification of the isotope effect due to pair breaking

International Nuclear Information System (INIS)

Carbotte, J.P.; Greeson, M.; Perez-Gonzalez, A.

1991-01-01

We have calculated the effect of pair breaking on the isotope-effect coefficient (β) of a superconductor. We find that, as the pair-breaking scattering rate is increased, β also increases in absolute value. Values of β much larger than the canonical value of 1/2 can easily be achieved even in models where the electron-phonon interaction contributes only a very small amount to the value of the intrinsic critical temperature

Neutron-proton isovector pairing effect on the nuclear moment of inertia

International Nuclear Information System (INIS)

Mokhtari, D.; Ami, I.; Fellah, M.; Allal, N.H.

2008-01-01

The neutron-proton (n-p) isovector pairing effect on the nuclear moment of inertia has been studied within the framework of the BCS approximation. An analytical expression of the moment of inertia, that explicitly depends upon the n-p pairing, has been established using the Inglis cranking model. The model was first tested numerically for nuclei such as N = Z and whose experimental values of the moment of inertia are known (i.e. such as 16 ≤ Z ≤ 40). It has been shown that the n-p pairing effect is non-negligible and clearly improves the theoretical predictions when compared to those of the pairing between like particles. Secondly, predictions have been established for even-even proton-rich rare-earth nuclei. It has been shown that the n-p pairing effect is non-negligible when N = Z and rapidly decreases with increasing values of (N-Z). (author)

Parietal lesion effects on cued recall following pair associate learning.

Science.gov (United States)

Ben-Zvi, Shir; Soroker, Nachum; Levy, Daniel A

2015-07-01

We investigated the involvement of the posterior parietal cortex in episodic memory in a lesion-effects study of cued recall following pair-associate learning. Groups of patients who had experienced first-incident stroke, generally in middle cerebral artery territory, and exhibited damage that included lateral posterior parietal regions, were tested within an early post-stroke time window. In three experiments, patients and matched healthy comparison groups executed repeated study and cued recall test blocks of pairs of words (Experiment 1), pairs of object pictures (Experiment 2), or pairs of object pictures and environmental sounds (Experiment 3). Patients' brain CT scans were subjected to quantitative analysis of lesion volumes. Behavioral and lesion data were used to compute correlations between area lesion extent and memory deficits, and to conduct voxel-based lesion-symptom mapping. These analyses implicated lateral ventral parietal cortex, especially the angular gyrus, in cued recall deficits, most pronouncedly in the cross-modal picture-sound pairs task, though significant parietal lesion effects were also found in the unimodal word pairs and picture pairs tasks. In contrast to an earlier study in which comparable parietal lesions did not cause deficits in item recognition, these results indicate that lateral posterior parietal areas make a substantive contribution to demanding forms of recollective retrieval as represented by cued recall, especially for complex associative representations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Alcohol’s Effects on Pair-Bond Maintenance in Male Prairie Voles

Directory of Open Access Journals (Sweden)

Andre T. Walcott

2017-11-01

Full Text Available Alcohol abuse can have devastating effects on social relationships. In particular, discrepant patterns of heavy alcohol consumption are associated with increased rates of separation and divorce. Previous studies have attempted to model these effects of alcohol using socially monogamous prairie voles. These studies showed that alcohol consumption can inhibit the formation of pair bonds in this species. While these findings indicated that alcohol’s effects on social attachments can involve biological mechanisms, the formation of pair bonds does not properly model long-term human attachments. To overcome this caveat, this study explored whether discordant or concordant alcohol consumption between individuals within established pairs affects maintenance of pair bonds in male prairie voles. Male and female prairie voles were allowed to form a pair bond for 1 week. Following this 1-week cohabitation period, males received access to 10% continuous ethanol; meanwhile, their female partners had access to either alcohol and water or just water. When there was a discrepancy in alcohol consumption, male prairie voles showed a decrease in partner preference (PP. Conversely, when concordant drinking occurred, males showed no inhibition in PP. Further analysis revealed a decrease in oxytocin immunoreactivity in the paraventricular nucleus of alcohol-exposed males that was independent of the drinking status of their female partners. On the other hand, only discordant alcohol consumption resulted in an increase of FosB immunoreactivity in the periaqueductal gray of male voles, a finding suggesting a potential involvement of this brain region in the effects of alcohol on maintenance of pair bonds. Our studies provide the first evidence that alcohol has effects on established pair bonds and that partner drinking status plays a large role in these effects.

Tearing modes with pressure gradient effect in pair plasmas

International Nuclear Information System (INIS)

Cai Huishan; Li Ding; Zheng Jian

2009-01-01

The general dispersion relation of tearing mode with pressure gradient effect in pair plasmas is derived analytically. If the pressure gradients of positron and electron are not identical in pair plasmas, the pressure gradient has significant influence at tearing mode in both collisionless and collisional regimes. In collisionless regime, the effects of pressure gradient depend on its magnitude. For small pressure gradient, the growth rate of tearing mode is enhanced by pressure gradient. For large pressure gradient, the growth rate is reduced by pressure gradient. The tearing mode can even be stabilized if pressure gradient is large enough. In collisional regime, the growth rate of tearing mode is reduced by the pressure gradient. While the positron and electron have equal pressure gradient, tearing mode is not affected by pressure gradient in pair plasmas.

The Effects of Reinforcer Pairing and Fading on Preschoolers' Snack Selections

Science.gov (United States)

Solberg, Katherine M.; Hanley, Gregory P.; Layer, Stacy A.; Ingvarsson, Einar T.

2007-01-01

The effects of reinforcement pairing and fading on preschoolers' snack selections were evaluated in a multiple baseline design. Baseline preferences for snack options were assessed via repeated paired-item preference assessments. Edible, social, and activity-based reinforcers were then exclusively paired with a less preferred snack option. Once…

Time-Resolved Magnetic Field Effects Distinguish Loose Ion Pairs from Exciplexes

Science.gov (United States)

2013-01-01

We describe the experimental investigation of time-resolved magnetic field effects in exciplex-forming organic donor–acceptor systems. In these systems, the photoexcited acceptor state is predominantly deactivated by bimolecular electron transfer reactions (yielding radical ion pairs) or by direct exciplex formation. The delayed fluorescence emitted by the exciplex is magnetosensitive if the reaction pathway involves loose radical ion pair states. This magnetic field effect results from the coherent interconversion between the electronic singlet and triplet radical ion pair states as described by the radical pair mechanism. By monitoring the changes in the exciplex luminescence intensity when applying external magnetic fields, details of the reaction mechanism can be elucidated. In this work we present results obtained with the fluorophore-quencher pair 9,10-dimethylanthracene/N,N-dimethylaniline (DMA) in solvents of systematically varied permittivity. A simple theoretical model is introduced that allows discriminating the initial state of quenching, viz., the loose ion pair and the exciplex, based on the time-resolved magnetic field effect. The approach is validated by applying it to the isotopologous fluorophore-quencher pairs pyrene/DMA and pyrene-d10/DMA. We detect that both the exciplex and the radical ion pair are formed during the initial quenching stage. Upon increasing the solvent polarity, the relative importance of the distant electron transfer quenching increases. However, even in comparably polar media, the exciplex pathway remains remarkably significant. We discuss our results in relation to recent findings on the involvement of exciplexes in photoinduced electron transfer reactions. PMID:24041160

Distinguishing familiarity from fluency for the compound word pair effect in associative recognition.

Science.gov (United States)

Ahmad, Fahad N; Hockley, William E

2017-09-01

We examined whether processing fluency contributes to associative recognition of unitized pre-experimental associations. In Experiments 1A and 1B, we minimized perceptual fluency by presenting each word of pairs on separate screens at both study and test, yet the compound word (CW) effect (i.e., hit and false-alarm rates greater for CW pairs with no difference in discrimination) did not reduce. In Experiments 2A and 2B, conceptual fluency was examined by comparing transparent (e.g., hand bag) and opaque (e.g., rag time) CW pairs in lexical decision and associative recognition tasks. Lexical decision was faster for transparent CWs (Experiment 2A) but in associative recognition, the CW effect did not differ by CW pair type (Experiment 2B). In Experiments 3A and 3B, we examined whether priming that increases processing fluency would influence the CW effect. In Experiment 3A, CW and non-compound word pairs were preceded with matched and mismatched primes at test in an associative recognition task. In Experiment 3B, only transparent and opaque CW pairs were presented. Results showed that presenting matched versus mismatched primes at test did not influence the CW effect. The CW effect in yes-no associative recognition is due to reliance on enhanced familiarity of unitized CW pairs.

Performance Limiting Flow Processes in High-State Loading High-Mach Number Compressors

National Research Council Canada - National Science Library

Tan, Choon S

2008-01-01

In high-stage loading high-Mach number (HLM) compressors, counter-rotating pairs of discrete vortices are shed at the trailing edge of the upstream blade row at a frequency corresponding to the downstream rotor blade passing frequency...

Coupling effects of grey-grey separate spatial screening soliton pairs

International Nuclear Information System (INIS)

Jiang Qichang; Su Yanli; Ji Xuanmang

2012-01-01

The existence and coupling effects of grey-grey separate spatial soliton pairs in a biased series non-photovoltaic photorefractive crystal circuit are investigated in this paper. The numerical solution of grey-grey soliton pairs is derived. The coupling effects between two grey solitons resulting from the input optical intensity and crystal temperature are analyzed numerically. The results show that when the input optical intensity of one crystal changes, two grey solitons in a soliton pair will all change; that is, two grey solitons can affect each other by the light-induced current that flows from one crystal to another. When the temperature of one crystal increases, the intensity width of the grey soliton in this crystal first decreases and then increases. Simultaneously, the intensity width of another grey soliton increases monotonically.

Pair Housing of Dairy Calves and Age at Pairing: Effects on Weaning Stress, Health, Production and Social Networks.

Science.gov (United States)

Bolt, Sarah L; Boyland, Natasha K; Mlynski, David T; James, Richard; Croft, Darren P

2017-01-01

The early social environment can influence the health and behaviour of animals, with effects lasting into adulthood. In Europe, around 60% of dairy calves are reared individually during their first eight weeks of life, while others may be housed in pairs or small groups. This study assessed the effects of varying degrees of social contact on weaning stress, health and production during pen rearing, and on the social networks that calves later formed when grouped. Forty female Holstein-Friesian calves were allocated to one of three treatments: individually housed (I, n = 8), pair-housed from day five (P5, n = 8 pairs), and pair-housed from day 28 (P28, n = 8 pairs). From day 48, calves were weaned by gradual reduction of milk over three days, and vocalisations were recorded as a measure of stress for three days before, during and after weaning. Health and production (growth rate and concentrate intakes) were not affected by treatment during the weaning period or over the whole study. Vocalisations were highest post-weaning, and were significantly higher in I calves than pair-reared calves. Furthermore, P28 calves vocalised significantly more than P5 calves. The social network of calves was measured for one month after all calves were grouped in a barn, using association data from spatial proximity loggers. We tested for week-week stability, social differentiation and assortment in the calf network. Additionally, we tested for treatment differences in: coefficient of variation (CV) in association strength, percentage of time spent with ex-penmate (P5 and P28 calves only) and weighted degree centrality (the sum of the strength of an individual's associations). The network was relatively stable from weeks one to four and was significantly differentiated, with individuals assorting based on prior familiarity. P5 calves had significantly higher CV in association strength than I calves in week one (indicating more heterogeneous social associations) but there were no

Effect of a Herbal-Leucine mix on the IL-1β-induced cartilage degradation and inflammatory gene expression in human chondrocytes

Directory of Open Access Journals (Sweden)

Haqqi Tariq M

2011-08-01

Full Text Available Abstract Background Conventional treatments for the articular diseases are often effective for symptom relief, but can also cause significant side effects and do not slow the progression of the disease. Several natural substances have been shown to be effective at relieving the symptoms of osteoarthritis (OA, and preliminary evidence suggests that some of these compounds may exert a favorable influence on the course of the disease. The objective of this study was to investigate the anti-inflammatory/chondroprotective potential of a Herbal and amino acid mixture containing extract of the Uncaria tomentosa, Boswellia spp., Lepidium meyenii and L-Leucine on the IL-1β-induced production of nitric oxide (NO, glycosaminoglycan (GAG, matrix metalloproteinases (MMPs, aggrecan (ACAN and type II collagen (COL2A1 in human OA chondrocytes and OA cartilage explants. Methods Primary OA chondrocytes or OA cartilage explants were pretreated with Herbal-Leucine mixture (HLM, 1-10 μg/ml and then stimulated with IL-1β (5 ng/ml. Effect of HLM on IL-1β-induced gene expression of iNOS, MMP-9, MMP-13, ACAN and COL2A1 was verified by real time-PCR. Estimation of NO and GAG release in culture supernatant was done using commercially available kits. Results HLM tested in these in vitro studies was found to be an effective anti-inflammatory agent, as evidenced by strong inhibition of iNOS, MMP-9 and MMP-13 expression and NO production in IL-1β-stimulated OA chondrocytes (p Leucine mixture (HLM up-regulation of ACAN and COL2A1 expression in IL-1β-stimulated OA chondrocytes was also noted (p Conclusion Our data suggests that HLM could be chondroprotective and anti-inflammatory agent in arthritis, switching chondrocyte gene expression from catabolic direction towards anabolic and regenerative, and consequently this approach may be potentially useful as a new adjunct therapeutic/preventive agent for OA or injury recovery.

Evaluating the Effects of Virtual Pair Programming on Students’ Achievement and Satisfaction

Directory of Open Access Journals (Sweden)

Nick Zacharis

2009-09-01

Full Text Available Pair programming is a lightweight software development technique in which two programmers work together at one computer. In literature, many benefits of pair programming have been proposed, such as increased productivity, improved code quality, enhanced job satisfaction and confidence. Although pair programming provides clear pedagogical benefits, its collocation requirement and the limited time during a lab session are serious barriers in the full deployment and evaluation of this programming technique. This paper reports on a study that investigated the effectiveness of Virtual Pair Programming (VPP on student performance and satisfaction in an introductory Java course where students worked collaboratively in pairs on homework programming assignments, using online tools that integrated desktop sharing and real time communication. The results of this study support previous research findings and suggest that VPP is an effective pedagogical tool for flexible collaboration and an acceptable alternative to individual/solo programming experience, regarding productivity, code quality, academic performance and student satisfaction.

Effective interionic pair potentials in liquid alkali metals

International Nuclear Information System (INIS)

Kumaravadivel, R.

1984-06-01

Information on the effective pair potential of liquid alkali metals is obtained from liquid structure factor data by the combination of two approximate methods in the theory of liquids. One method stems from treating the indirect ion-ion interaction in the optimised random phase approximation (ORPA) and the other uses the modified hypernetted chain (MHNC) equation. It is shown that, in the region of the main attractive well, the effective pair potential is bracketed by the results obtained from these two methods. The MHNC inversion scheme does not fare well in providing information on the potential in the region of interionic distance in the tail of the interionic potential. A cross-over from the hard-sphere bridge function to the mean spherical approximation (MSA) bridge function for the long range behaviour of the bridge term in the MHNC equation does not provide appreciable improvement. (author)

Aliasing effects in digital images of line-pair phantoms

International Nuclear Information System (INIS)

Albert, Michael; Beideck, Daniel J.; Bakic, Predrag R.; Maidment, Andrew D.A.

2002-01-01

Line-pair phantoms are commonly used for evaluating screen-film systems. When imaged digitally, aliasing effects give rise to additional periodic patterns. This paper examines one such effect that medical physicists are likely to encounter, and which can be used as an indicator of super-resolution

Effects of pairing correlation on nuclear level density parameter and nucleon separation energy

International Nuclear Information System (INIS)

Rajesekaran, T.R.; Selvaraj, S.

2002-01-01

A systematic study of effects of pairing correlations on nuclear level density parameter 'a' and neutron separation energy S N is presented for 152 Gd using statistical theory of nuclei with deformation, collective and noncollective rotational degrees of freedom, shell effects, and pairing correlations

Influence of isovector pairing and particle-number projection effects on spectroscopic factors for one-pair like-particle transfer reactions in proton-rich even-even nuclei

Science.gov (United States)

Benbouzid, Y.; Allal, N. H.; Fellah, M.; Oudih, M. R.

2018-04-01

Isovector neutron-proton (np) pairing and particle-number fluctuation effects on the spectroscopic factors (SF) corresponding to one-pair like-particle transfer reactions in proton-rich even-even nuclei are studied. With this aim, expressions of the SF corresponding to two-neutron stripping and two-proton pick-up reactions, which take into account the isovector np pairing effect, are established within the generalized BCS approach, using a schematic definition proposed by Chasman. Expressions of the same SF which strictly conserve the particle number are also established within the Sharp-BCS (SBCS) discrete projection method. In both cases, it is shown that these expressions generalize those obtained when only the pairing between like particles is considered. First, the formalism is tested within the Richardson schematic model. Second, it is applied to study even-even proton-rich nuclei using the single-particle energies of a Woods-Saxon mean-field. In both cases, it is shown that the np pairing effect and the particle-number projection effect on the SF values are important, particularly in N = Z nuclei, and must then be taken into account.

Cytoplasmic and Genomic Effects on Meiotic Pairing in Brassica Hybrids and Allotetraploids from Pair Crosses of Three Cultivated Diploids

Science.gov (United States)

Cui, Cheng; Ge, Xianhong; Gautam, Mayank; Kang, Lei; Li, Zaiyun

2012-01-01

Interspecific hybridization and allopolyploidization contribute to the origin of many important crops. Synthetic Brassica is a widely used model for the study of genetic recombination and “fixed heterosis” in allopolyploids. To investigate the effects of the cytoplasm and genome combinations on meiotic recombination, we produced digenomic diploid and triploid hybrids and trigenomic triploid hybrids from the reciprocal crosses of three Brassica diploids (B. rapa, AA; B. nigra, BB; B. oleracea, CC). The chromosomes in the resultant hybrids were doubled to obtain three allotetraploids (B. juncea, AA.BB; B. napus, AA.CC; B. carinata, BB.CC). Intra- and intergenomic chromosome pairings in these hybrids were quantified using genomic in situ hybridization and BAC-FISH. The level of intra- and intergenomic pairings varied significantly, depending on the genome combinations and the cytoplasmic background and/or their interaction. The extent of intragenomic pairing was less than that of intergenomic pairing within each genome. The extent of pairing variations within the B genome was less than that within the A and C genomes, each of which had a similar extent of pairing. Synthetic allotetraploids exhibited nondiploidized meiotic behavior, and their chromosomal instabilities were correlated with the relationship of the genomes and cytoplasmic background. Our results highlight the specific roles of the cytoplasm and genome to the chromosomal behaviors of hybrids and allopolyploids. PMID:22505621

Neutron-proton pairing effect on the proton-rich nuclei moment of inertia

International Nuclear Information System (INIS)

Mokhtari, D.; Ami, I.; Fellah, M.; Allal, N.H.; Fellah, M.; Allal, N.H.

2008-01-01

The neutron-proton (n-p) pairing effect on the nuclear moment of inertia is studied within the BCS approximation in the isovector case. An analytical expression of the moment of inertia is established by means of the cranking model. This expression generalizes the usual BCS one (i.e. when only the pairing between like-particles is considered). The moment of inertia of N = Z even-even nuclei, for which experimental values are known, i.e., such as 32 ≤ A ≤ 80, has been numerically evaluated, with and without inclusion of the n-p pairing effect. The used single-particle and Eigen-states are those of a deformed Woods-Saxon mean field. It turns out that the inclusion of the n-p pairing improves the obtained values when compared to the usual BCS approximation, since the average discrepancies with the experimental data are respectively 7% and 37%. (authors)

Neutron-proton pairing effect on the proton-rich nuclei moment of inertia

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, D.; Ami, I.; Fellah, M.; Allal, N.H. [Laboratoire de Physique Theorique, Faculte de Physique, USTHB, Algiers (Algeria); Fellah, M.; Allal, N.H. [Centre de Recherche Nucleaire d' Alger, COMENA, Algiers (Algeria)

2008-07-01

The neutron-proton (n-p) pairing effect on the nuclear moment of inertia is studied within the BCS approximation in the isovector case. An analytical expression of the moment of inertia is established by means of the cranking model. This expression generalizes the usual BCS one (i.e. when only the pairing between like-particles is considered). The moment of inertia of N = Z even-even nuclei, for which experimental values are known, i.e., such as 32 {<=} A {<=} 80, has been numerically evaluated, with and without inclusion of the n-p pairing effect. The used single-particle and Eigen-states are those of a deformed Woods-Saxon mean field. It turns out that the inclusion of the n-p pairing improves the obtained values when compared to the usual BCS approximation, since the average discrepancies with the experimental data are respectively 7% and 37%. (authors)

Effects of disorder on the electron pairing

International Nuclear Information System (INIS)

Oviedo-Roa, R.; Wang, C.; Navarro, O.

1996-01-01

The electron pairing in randomly disordered lattices is studied by using an attractive Hubbard model, and by mapping the many-body problem onto a tight-binding one in a higher dimensional space, where a diagonal disorder is considered within the coherent-potential approximation. The results show an enhancement of the pair-binding energy as the self-energy difference increases in a binary alloy A x B 1-x . This fact suggests that the pairing process is highly sensitive to the one-particle localization condition. A ground-state phase diagram for on-site interaction disorder shows regions where pairing is avoided for ordered diatomic systems but not for disordered case

Diethylstilbestrol can effectively accelerate estradiol-17-O-glucuronidation, while potently inhibiting estradiol-3-O-glucuronidation

International Nuclear Information System (INIS)

Zhu, Liangliang; Xiao, Ling; Xia, Yangliu; Zhou, Kun; Wang, Huili; Huang, Minyi; Ge, Guangbo; Wu, Yan; Wu, Ganlin; Yang, Ling

2015-01-01

This in vitro study investigates the effects of diethylstilbestrol (DES), a widely used toxic synthetic estrogen, on estradiol-3- and 17-O- (E2-3/17-O) glucuronidation, via culturing human liver microsomes (HLMs) or recombinant UDP-glucuronosyltransferases (UGTs) with DES and E2. DES can potently inhibit E2-3-O-glucuronidation in HLM, a probe reaction for UGT1A1. Kinetic assays indicate that the inhibition follows a competitive inhibition mechanism, with the Ki value of 2.1 ± 0.3 μM, which is less than the possible in vivo level. In contrast to the inhibition on E2-3-O-glucuronidation, the acceleration is observed on E2-17-O-glucuronidation in HLM, in which cholestatic E2-17-O-glucuronide is generated. In the presence of DES (0–6.25 μM), K m values for E2-17-O-glucuronidation are located in the range of 7.2–7.4 μM, while V max values range from 0.38 to 1.54 nmol/min/mg. The mechanism behind the activation in HLM is further demonstrated by the fact that DES can efficiently elevate the activity of UGT1A4 in catalyzing E2-17-O-glucuronidation. The presence of DES (2 μM) can elevate V max from 0.016 to 0.81 nmol/min/mg, while lifting K m in a much lesser extent from 4.4 to 11 μM. Activation of E2-17-O-glucuronidation is well described by a two binding site model, with K A , α, and β values of 0.077 ± 0.18 μM, 3.3 ± 1.1 and 104 ± 56, respectively. However, diverse effects of DES towards E2-3/17-O-glucuronidation are not observed in liver microsomes from several common experimental animals. In summary, this study issues new potential toxic mechanisms for DES: potently inhibiting the activity of UGT1A1 and powerfully accelerating the formation of cholestatic E2-17-O-glucuronide by UGT1A4. - Highlights: • E2-3-O-glucuronidation in HLM is inhibited when co-incubated with DES. • E2-17-O-glucuronidation in HLM is stimulated when co-incubated with DES. • Acceleration of E2-17-O-glucuronidationin in HLM by DES is via activating the activity of UGT1A4

Diethylstilbestrol can effectively accelerate estradiol-17-O-glucuronidation, while potently inhibiting estradiol-3-O-glucuronidation

Energy Technology Data Exchange (ETDEWEB)

Zhu, Liangliang; Xiao, Ling [The Centre for Drug and Food Safety Evaluation, School of Life Science, Anqing Normal University, Anqing 246011 (China); Xia, Yangliu [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Zhou, Kun [College of Pharmacy, Liaoning University of Traditional Chinese Medicine, Dalian 116600 (China); Wang, Huili; Huang, Minyi [The Centre for Drug and Food Safety Evaluation, School of Life Science, Anqing Normal University, Anqing 246011 (China); Ge, Guangbo, E-mail: geguangbo@dicp.ac.cn [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Wu, Yan; Wu, Ganlin [The Centre for Drug and Food Safety Evaluation, School of Life Science, Anqing Normal University, Anqing 246011 (China); Yang, Ling, E-mail: yling@dicp.ac.cn [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

2015-03-01

This in vitro study investigates the effects of diethylstilbestrol (DES), a widely used toxic synthetic estrogen, on estradiol-3- and 17-O- (E2-3/17-O) glucuronidation, via culturing human liver microsomes (HLMs) or recombinant UDP-glucuronosyltransferases (UGTs) with DES and E2. DES can potently inhibit E2-3-O-glucuronidation in HLM, a probe reaction for UGT1A1. Kinetic assays indicate that the inhibition follows a competitive inhibition mechanism, with the Ki value of 2.1 ± 0.3 μM, which is less than the possible in vivo level. In contrast to the inhibition on E2-3-O-glucuronidation, the acceleration is observed on E2-17-O-glucuronidation in HLM, in which cholestatic E2-17-O-glucuronide is generated. In the presence of DES (0–6.25 μM), K{sub m} values for E2-17-O-glucuronidation are located in the range of 7.2–7.4 μM, while V{sub max} values range from 0.38 to 1.54 nmol/min/mg. The mechanism behind the activation in HLM is further demonstrated by the fact that DES can efficiently elevate the activity of UGT1A4 in catalyzing E2-17-O-glucuronidation. The presence of DES (2 μM) can elevate V{sub max} from 0.016 to 0.81 nmol/min/mg, while lifting K{sub m} in a much lesser extent from 4.4 to 11 μM. Activation of E2-17-O-glucuronidation is well described by a two binding site model, with K{sub A}, α, and β values of 0.077 ± 0.18 μM, 3.3 ± 1.1 and 104 ± 56, respectively. However, diverse effects of DES towards E2-3/17-O-glucuronidation are not observed in liver microsomes from several common experimental animals. In summary, this study issues new potential toxic mechanisms for DES: potently inhibiting the activity of UGT1A1 and powerfully accelerating the formation of cholestatic E2-17-O-glucuronide by UGT1A4. - Highlights: • E2-3-O-glucuronidation in HLM is inhibited when co-incubated with DES. • E2-17-O-glucuronidation in HLM is stimulated when co-incubated with DES. • Acceleration of E2-17-O-glucuronidationin in HLM by DES is via activating the

On the Josephson effect between superconductors in singlet and triplet spin-pairing states

International Nuclear Information System (INIS)

Pals, J.A.; Haeringen, W. van

1977-01-01

An expression is derived for the Josephson current between two weakly coupled superconductors of which one or both have pairs in a spin-triplet state. It is shown that there can be no Josephson effect up to second order in the transition matrix elements between a superconductor with spin-triplet pairs and one with spin-singlet pairs if the coupling between the two superconductors can be described with a spin-conserving tunnel hamiltonian. This is shown to offer a possibility to investigate experimentally whether a particular superconductor has spin-triplet pairs by coupling it weakly to a well-known spin-singlet pairing superconductor. (Auth.)

Evaluating Effectiveness of Pair Programming as a Teaching Tool in Programming Courses

Science.gov (United States)

Faja, Silvana

2014-01-01

This study investigates the effectiveness of pair programming on student learning and satisfaction in introductory programming courses. Pair programming, used in the industry as a practice of an agile development method, can be adopted in classroom settings to encourage peer learning, increase students' social skills, and enhance student…

Pairing and deformation effects in nuclear excitation spectra

Energy Technology Data Exchange (ETDEWEB)

Repko, A. [Slovak Academy of Sciences, Institute of Physics, Bratislava (Slovakia); Kvasil, J. [Charles University, Institute of Particle and Nuclear Physics, Prague (Czech Republic); Nesterenko, V.O. [Joint Institute for Nuclear Research, Laboratory of Theoretical Physics, Dubna (Russian Federation); State University ' ' Dubna' ' , Dubna (Russian Federation); Reinhard, P.G. [Universitaet Erlangen, Institut fuer Theoretische Physik II, Erlangen (Germany)

2017-11-15

We investigate effects of pairing and of quadrupole deformation on two sorts of nuclear excitations, γ-vibrational K{sup π} = 2{sup +} states and dipole resonances (isovector dipole, pygmy, compression, toroidal). The analysis is performed within the quasiparticle random phase approximation (QRPA) based on the Skyrme energy functional using the Skyrme parametrization SLy6. Particular attention is paid to i) the role of the particle-particle (pp) channel in the residual interaction of QRPA, ii) comparison of volume pairing (VP) and surface pairing (SP), iii) peculiarities of deformation splitting in the various resonances. We find that the impact of the pp-channel on the considered excitations is negligible. This conclusion applies also to any other excitation except for the K{sup π} = 0{sup +} states. Furthermore, the difference between VP and SP is found small (with exception of peak height in the toroidal mode). In the low-energy isovector dipole (pygmy) and isoscalar toroidal modes, the branch K{sup π} = 1{sup -} is shown to dominate over the K{sup π} = 0{sup -} one in the range of excitation energy E < 8-10 MeV. The effect becomes impressive for the toroidal resonance whose low-energy part is concentrated in a high peak of almost pure K{sup π} = 1{sup -} nature. This peculiarity may be used as a fingerprint of the toroidal mode in future experiments. The interplay between pygmy, toroidal and compression resonances is discussed, the interpretation of the observed isoscalar giant dipole resonance is partly revised. (orig.)

Effects of Ion Beam Irradiation on Nanoscale InOx Cooper-Pair Insulators

Directory of Open Access Journals (Sweden)

Srdjan Milosavljević

2013-01-01

Full Text Available This paper examines the effects of irradiating indium oxide films of nanoscale thickness by ion beams, when these films are in the Cooper-pair insulator state. Radiation effects are predicted on the basis of Monte Carlo simulations of ion transport. Results of numerical experiments are interpreted within the theoretical model of a Cooper-pair insulator. The study suggests that radiation-induced changes in InOx films exposed to ion beams could significantly alter their current-voltage characteristics and that a transition to a metallic state is possible, due to radiation-induced perturbation of the fine-tuned granular structure. Furthermore, incident and displaced ions can break up enough Cooper pairs in InOx films to cause dissolution of this specific insulating state.

Effect of hang cleans or squats paired with countermovement vertical jumps on vertical displacement.

Science.gov (United States)

Andrews, Tedi R; Mackey, Theresa; Inkrott, Thomas A; Murray, Steven R; Clark, Ida E; Pettitt, Robert W

2011-09-01

Complex training is characterized by pairing resistance exercise with plyometric exercise to exploit the postactivation potentiation (PAP) phenomenon, thereby promising a better training effect. Studies on PAP as measured by human power performances are equivocal. One issue may be the lack of analyses across multiple sets of paired exercises, a common practice used by athletes. We evaluated countermovement vertical jump (CMJ) performance in 19 women, collegiate athletes in 3 of the following trials: (a) CMJs-only, where 1 set of CMJs served as a conditioning exercise, (b) heavy-load, back squats paired with CMJs, and (c) hang cleans paired with CMJs. The CMJ vertical displacement (3-attempt average), as measured with digital video, served as the dependent variable of CMJ performance. Across 3 sets of paired-exercise regimens, CMJ-only depreciated 1.6 cm and CMJ paired with back squats depreciated 2.0 cm (main effect, p squats or CMJs in and of themselves. Future research on exercise modes of complex training that best help athletes preserve and train with the highest power possible, in a given training session, is warranted.

Comparison of methods of extracting information for meta-analysis of observational studies in nutritional epidemiology

Directory of Open Access Journals (Sweden)

Jong-Myon Bae

2016-01-01

Full Text Available OBJECTIVES: A common method for conducting a quantitative systematic review (QSR for observational studies related to nutritional epidemiology is the “highest versus lowest intake” method (HLM, in which only the information concerning the effect size (ES of the highest category of a food item is collected on the basis of its lowest category. However, in the interval collapsing method (ICM, a method suggested to enable a maximum utilization of all available information, the ES information is collected by collapsing all categories into a single category. This study aimed to compare the ES and summary effect size (SES between the HLM and ICM. METHODS: A QSR for evaluating the citrus fruit intake and risk of pancreatic cancer and calculating the SES by using the HLM was selected. The ES and SES were estimated by performing a meta-analysis using the fixed-effect model. The directionality and statistical significance of the ES and SES were used as criteria for determining the concordance between the HLM and ICM outcomes. RESULTS: No significant differences were observed in the directionality of SES extracted by using the HLM or ICM. The application of the ICM, which uses a broader information base, yielded more-consistent ES and SES, and narrower confidence intervals than the HLM. CONCLUSIONS: The ICM is advantageous over the HLM owing to its higher statistical accuracy in extracting information for QSR on nutritional epidemiology. The application of the ICM should hence be recommended for future studies.

Pairing correlations in nuclei

International Nuclear Information System (INIS)

Baba, C.V.K.

1988-01-01

There are many similarities between the properties of nucleons in nuclei and electrons in metals. In addition to the properties explainable in terms of independent particle motion, there are many important co-operative effects suggesting correlated motion. Pairing correlation which leads to superconductivity in metals and several important properties in nuclei , is an exmple of such correlations. An attempt has been made to review the effects of pairing correlations in nuclei. Recent indications of reduction in pairing correlations at high angular momenta is discussed. A comparision between pairing correlations in the cases of nuclei and electrons in metals is attempted. (author). 20 refs., 10 figs

Intermittent pair-housing, pair relationship qualities, and HPA activity in adult female rhesus macaques.

Science.gov (United States)

Hannibal, Darcy L; Cassidy, Lauren C; Vandeleest, Jessica; Semple, Stuart; Barnard, Allison; Chun, Katie; Winkler, Sasha; McCowan, Brenda

2018-05-02

Laboratory rhesus macaques are often housed in pairs and may be temporarily or permanently separated for research, health, or management reasons. While both long-term social separations and introductions can stimulate a stress response that impacts inflammation and immune function, the effects of short-term overnight separations and whether qualities of the pair relationship mediate these effects are unknown. In this study, we investigated the effects of overnight separations on the urinary cortisol concentration of 20 differentially paired adult female rhesus macaques (Macaca mulatta) at the California National Primate Research Center. These females were initially kept in either continuous (no overnight separation) or intermittent (with overnight separation) pair-housing and then switched to the alternate pair-housing condition part way through the study. Each study subject was observed for 5 weeks, during which we collected measures of affiliative, aggressive, anxious, abnormal, and activity-state behaviors in both pair-housing conditions. Additionally, up to three urine samples were collected from each subject per week and assayed for urinary free cortisol and creatinine. Lastly, the behavioral observer scored each pair on four relationship quality attributes ("Anxious," "Tense," "Well-meshed," and "Friendly") using a seven-point scale. Data were analyzed using a generalized linear model with gamma distribution and an information theoretic approach to determine the best model set. An interaction between the intermittent pairing condition and tense pair adjective rating was in the top three models of the best model set. Dominance and rates of affiliation were also important for explaining urinary cortisol variation. Our results suggest that to prevent significant changes in HPA-axis activation in rhesus macaque females, which could have unintended effects on research outcomes, pairs with "Tense" relationships and overnight separations preventing tactile contact

Charge Aspects of Composite Pair Superconductivity

Science.gov (United States)

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.

Pair-breaking effects by parallel magnetic field in electric-field-induced surface superconductivity

International Nuclear Information System (INIS)

Nabeta, Masahiro; Tanaka, Kenta K.; Onari, Seiichiro; Ichioka, Masanori

2016-01-01

Highlights: • Zeeman effect shifts superconducting gaps of sub-band system, towards pair-breaking. • Higher-level sub-bands become normal-state-like electronic states by magnetic fields. • Magnetic field dependence of zero-energy DOS reflects multi-gap superconductivity. - Abstract: We study paramagnetic pair-breaking in electric-field-induced surface superconductivity, when magnetic field is applied parallel to the surface. The calculation is performed by Bogoliubov-de Gennes theory with s-wave pairing, including the screening effect of electric fields by the induced carriers near the surface. Due to the Zeeman shift by applied fields, electronic states at higher-level sub-bands become normal-state-like. Therefore, the magnetic field dependence of Fermi-energy density of states reflects the multi-gap structure in the surface superconductivity.

Effects of the particle-number projection on the isovector pairing energy

International Nuclear Information System (INIS)

Allal, N.H.; Fellah, M.; Oudih, M.R.; Benhamouda, N.

2006-01-01

The usual neutron-proton BCS wave function is simultaneously projected on both the good neutron and proton numbers using a discrete projection operator. The projected energy of the system is deduced as a limit of rapidly convergent sequence. It is numerically studied for the N=Z nuclei of which ''experimental'' pairing gaps may be deduced from the experimental odd-even mass differences. It then appears that the particle-number fluctuation effect is even more important than in the case of pairing between like-particles. (orig.)

Effects of Student Pairing and Public Review on Physical Activity during School Recess

Science.gov (United States)

Zerger, Heather M.; Miller, Bryon G.; Valbuena, Diego; Miltenberger, Raymond G.

2017-01-01

The purpose of this study was to evaluate the effects of student pairing and feedback during recess on children's step counts. During baseline, participants wore a sealed pedometer during recess. During intervention, we paired participants with higher step counts with participants with lower step counts. We encouraged teams to compete for the…

Distortion-product otoacoustic emissions: body position effects with simultaneous presentation of tone pairs

Directory of Open Access Journals (Sweden)

Samuel R. Atcherson

2011-11-01

Full Text Available This study examined the effect of three different body positions on distortion-product otoacoustic emission (DPOAE amplitude and noise levels with multiple primary tone pairs simultaneously-presented to 36 normal-hearing female human adults. Other studies have demonstrated that the simultaneously presented tone pairs method shows clinical promise as a screener, but the sequential method remains in widespread clinical use. Postural changes have been suggested to have an effect not only on DPOAEs, but also transient-evoked OAEs and stimulus- frequency OAEs. DPOAE amplitude and noise levels were recorded in seated, supine, and side-lying positions to the following order of simultaneously-presented tone pairs relative to the f2 frequencies: 1187, 2375, and 4812 Hz; 1500, 3000, and 6062 Hz; and 1875, 3812, and 7625 Hz. No DPOAE could be detected reliably at 7625 Hz as result of poor signal-to-noise ratio. For remaining DPOAEs, statistical analyses revealed that amplitudes were not significantly different among the three body positions. However, at 1500 Hz and below, body position did have a statistically significant effect on noise levels though they are likely clinically negligible. Except at 7625 Hz, results suggest that DPOAEs recorded using a simultaneously presented tone pairs appear to be comparably recorded regardless of an individual’s body position.

Quark pair creation in color electric fields and effects of magnetic fields

International Nuclear Information System (INIS)

Tanji, Noato

2010-01-01

The time evolution of a system where a uniform and classical SU(3) color electric field and quantum fields of quarks interact with each other is studied focusing on non-perturbative pair creation and its back reaction. We characterize a color direction of an electric field in a gauge invariant way, and investigate its dependence. Momentum distributions of created quarks show plasma oscillation as well as quantum effects such as the Pauli blocking and interference. Pressure of the system is also calculated, and we show that pair creation moderates degree of anisotropy of pressure. Furthermore, enhancement of pair creation and induction of chiral charge under a color magnetic field which is parallel to an electric field are discussed.

Hyper-Binding across Time: Age Differences in the Effect of Temporal Proximity on Paired-Associate Learning

Science.gov (United States)

Campbell, Karen L.; Trelle, Alexandra; Hasher, Lynn

2014-01-01

Older adults show hyper- (or excessive) binding effects for simultaneously and sequentially presented distraction. Here, we addressed the potential role of hyper-binding in paired-associate learning. Older and younger adults learned a list of word pairs and then received an associative recognition task in which rearranged pairs were formed from…

An effective pair potential for liquid semiconductor, Se: Structure and ...

Indian Academy of Sciences (India)

The effective pair potential of liquid semiconductor Se is extracted from its experimental structure factor data using an accurate liquid state theory and this shows important basic features. A model potential incorporating the basic features of the structure factor extracted potential is suggested. This model potential is then used ...

Electron-hole pair effects in methane dissociative chemisorption on Ni(111)

Energy Technology Data Exchange (ETDEWEB)

Luo, Xuan; Jiang, Bin, E-mail: bjiangch@ustc.edu.cn [Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Juaristi, J. Iñaki [Centro de Física de Materiales CFM/MPC(CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 San Sebastián (Spain); Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián (Spain); Departamento de Física de Materiales, Facultad de Químicas, Universidad del País Vasco (UPV/EHU), Apartado 1072, 20080 San Sebastián (Spain); Alducin, Maite [Centro de Física de Materiales CFM/MPC(CSIC-UPV/EHU), P. Manuel de Lardizabal 5, 20018 San Sebastián (Spain); Donostia International Physics Center DIPC, P. Manuel de Lardizabal 4, 20018 San Sebastián (Spain); Guo, Hua [Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

2016-07-28

The dissociative chemisorption of methane on metal surfaces has attracted much attention in recent years as a prototype of gas-surface reactions in understanding the mode specific and bond selective chemistry. In this work, we systematically investigate the influence of electron-hole pair excitations on the dissociative chemisorption of CH{sub 4}/CH{sub 3}D/CHD{sub 3} on Ni(111). The energy dissipation induced by surface electron-hole pair excitations is modeled as a friction force introduced in the generalized Langevin equation, in which the independent atomic friction coefficients are determined within the local-density friction approximation. Quasi-classical trajectory calculations for CH{sub 4}/CH{sub 3}D/CHD{sub 3} have been carried out on a recently developed twelve-dimensional potential energy surface. Comparing the dissociation probabilities obtained with and without friction, our results clearly indicate that the electron-hole pair effects are generally small, both on absolute reactivity of each vibrational state and on the mode specificity and bond selectivity. Given similar observations in both water and methane dissociation processes, we conclude that electron-hole pair excitations would not play an important role as long as the reaction is direct and the interaction time between the molecule and metal electrons is relatively short.

Strong temperature effect on the sizes of the Cooper pairs in a two-band superconductor

Science.gov (United States)

Örd, Teet; Rägo, Küllike; Vargunin, Artjom; Litak, Grzegorz

2018-01-01

We study the temperature dependencies of the mean sizes of the Cooper pairs in a two-band BCS-type s-wave superconductivity model with coupling cut-off in the momentum space. It is found that, in contrast to single-band systems, the size of Cooper pairs in the weaker superconductivity band can significantly decrease with a temperature increase due to an interband proximity effect. The relevant spatial behaviour of the wave functions of the Cooper pairs is analyzed. The results also indicate a possibility that the size of Cooper pairs in two-band systems may increase with an increase in temperature.

Half-integer flux quantum effect in cuprate superconductors - a probe of pairing symmetry

International Nuclear Information System (INIS)

Tsuei, C.C.; Kirtley, J.R.; Gupta, A.; Sun, J.Z.; Moler, K.A.; Wang, J.H.

1996-01-01

Based on macroscopic quantum coherence effects arising from pair tunneling and flux quantization, a series of tricrystal experiments have been designed and carried out to test the order parameter symmetry in high-T c cuprate superconductors. By using a scanning SQUID microscope, we have directly and non-invasively observed the spontaneously generated half-integer flux quantum effect in controlled-orientation tricrystal cuprate superconducting systems. The presence or absence of the half-integer flux quantum effect as a function of the tricrystal geometry allows us to prove that the order parameter symmetry in the YBCO and Tl2201 systems is consistent with that of the d x 2 -y 2 pair state. (orig.)

Schwinger pair creation of Kaluza-Klein particles: Pair creation without tunneling

International Nuclear Information System (INIS)

Friedmann, Tamar; Verlinde, Herman

2005-01-01

We study Schwinger pair creation of charged Kaluza-Klein (KK) particles from a static KK electric field. We find that the gravitational backreaction of the electric field on the geometry--which is incorporated via the electric KK-Melvin solution--prevents the electrostatic potential from overcoming the rest mass of the KK particles, thus impeding the tunneling mechanism which is often thought of as responsible for the pair creation. However, we find that pair creation still occurs with a finite rate formally similar to the classic Schwinger result, but via an apparently different mechanism, involving a combination of the Unruh effect and vacuum polarization due to the E-field

Multi-pair states in electron–positron pair creation

Directory of Open Access Journals (Sweden)

Anton Wöllert

2016-09-01

Full Text Available 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.

Multi-pair states in electron–positron pair creation

Energy Technology Data Exchange (ETDEWEB)

Wöllert, Anton, E-mail: woellert@mpi-hd.mpg.de; Bauke, Heiko, E-mail: heiko.bauke@mpi-hd.mpg.de; Keitel, Christoph H.

2016-09-10

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.

Multi-pair states in electron–positron pair creation

International Nuclear Information System (INIS)

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

2016-01-01

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.

Dynamical pairing correlations in rotating nuclei

International Nuclear Information System (INIS)

Szymanski, Z.

1985-01-01

When the atomic nucleus rotates fast enough the static pair correlations may be destroyed. In this situation the pair-vibrations become an important manifestation of the short-range attractive pairing force. The influence of this effect on nuclear properties at high spin is discussed. (orig.)

Quantifying inbreeding avoidance through extra-pair reproduction.

Science.gov (United States)

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. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Experiment and modeling of paired effect on evacuation from a three-dimensional space

Energy Technology Data Exchange (ETDEWEB)

Jun, Hu [MOE Key Laboratory for Urban Transportation Complex Systems Theory and Technology, Beijing Jiaotong University, Beijing 100044 (China); School of Traffic and Transportation, Beijing Jiaotong University, Beijing 100044 (China); Faculty of Computer Science, Chengdu Normal University, Chengdu 611130 (China); Huijun, Sun, E-mail: hjsun1@bjtu.edu.cn [MOE Key Laboratory for Urban Transportation Complex Systems Theory and Technology, Beijing Jiaotong University, Beijing 100044 (China); School of Traffic and Transportation, Beijing Jiaotong University, Beijing 100044 (China); Juan, Wei [Faculty of Computer Science, Chengdu Normal University, Chengdu 611130 (China); Xiaodan, Chen [College of Information Science and Technology, Chengdu University, Chengdu 610106 (China); Lei, You [Faculty of Computer Science, Chengdu Normal University, Chengdu 611130 (China); College of Information Science and Technology, Chengdu University, Chengdu 610106 (China); Musong, Gu [Faculty of Computer Science, Chengdu Normal University, Chengdu 611130 (China)

2014-10-24

A novel three-dimensional cellular automata evacuation model was proposed based on stairs factor for paired effect and variety velocities in pedestrian evacuation. In the model pedestrians' moving probability of target position at the next moment was defined based on distance profit and repulsive force profit, and evacuation strategy was elaborated in detail through analyzing variety velocities and repulsive phenomenon in moving process. At last, experiments with the simulation platform were conducted to study the relationships of evacuation time, average velocity and pedestrian velocity. The results showed that when the ratio of single pedestrian was higher in the system, the shortest route strategy was good for improving evacuation efficiency; in turn, if ratio of paired pedestrians was higher, it is good for improving evacuation efficiency to adopt strategy that avoided conflicts, and priority should be given to scattered evacuation. - Highlights: • A novel three-dimensional evacuation model was presented with stair factor. • The paired effect and variety velocities were considered in evacuation model. • The cellular automata model is improved by repulsive force.

Experiment and modeling of paired effect on evacuation from a three-dimensional space

International Nuclear Information System (INIS)

Jun, Hu; Huijun, Sun; Juan, Wei; Xiaodan, Chen; Lei, You; Musong, Gu

2014-01-01

A novel three-dimensional cellular automata evacuation model was proposed based on stairs factor for paired effect and variety velocities in pedestrian evacuation. In the model pedestrians' moving probability of target position at the next moment was defined based on distance profit and repulsive force profit, and evacuation strategy was elaborated in detail through analyzing variety velocities and repulsive phenomenon in moving process. At last, experiments with the simulation platform were conducted to study the relationships of evacuation time, average velocity and pedestrian velocity. The results showed that when the ratio of single pedestrian was higher in the system, the shortest route strategy was good for improving evacuation efficiency; in turn, if ratio of paired pedestrians was higher, it is good for improving evacuation efficiency to adopt strategy that avoided conflicts, and priority should be given to scattered evacuation. - Highlights: • A novel three-dimensional evacuation model was presented with stair factor. • The paired effect and variety velocities were considered in evacuation model. • The cellular automata model is improved by repulsive force

On the pair creation effect in radiative charmonium transitions

International Nuclear Information System (INIS)

Lewin, K.

1985-01-01

Contribution to radiative charmonium decay amplitudes which come from Feynman diagrams containing creation of internal c anti c quark pair is investigated. The a im of the paper is calulation of this pair creation correction to the wave function overlap integral of the transition amplitude in a quasilocal semirelativistic approximation which works for charmed and heavier quark pairs. The application to the decay width of the spin flip transition psi(3685) → γchi(3415) givesa 12% correction to the nopair term using a meson radius near 0.5 Fm and a scale parameter Λ=400 MeV taken from fits inchar=monium spectroscopy. The error of the approximation is estimated to be smaller than 50%. The investigation indicates that also in the case of electroweak meson decays quatitative results cannot be expected from the no-pair contribution alone

When mothers make sons sexy: maternal effects contribute to the increased sexual attractiveness of extra-pair offspring.

Science.gov (United States)

Tschirren, Barbara; Postma, Erik; Rutstein, Alison N; Griffith, Simon C

2012-03-22

Quality differences between offspring sired by the social and by an extra-pair partner are usually assumed to have a genetic basis, reflecting genetic benefits of female extra-pair mate choice. In the zebra finch (Taeniopygia guttata), we identified a colour ornament that is under sexual selection and appears to have a heritable basis. Hence, by engaging in extra-pair copulations with highly ornamented males, females could, in theory, obtain genes for increased offspring attractiveness. Indeed, sons sired by extra-pair partners had larger ornaments, seemingly supporting the genetic benefit hypothesis. Yet, when comparing ornament size of the social and extra-pair partners, there was no difference. Hence, the observed differences most likely had an environmental basis, mediated, for example, via differential maternal investment of resources into the eggs fertilized by extra-pair and social partners. Such maternal effects may (at least partly) be mediated by egg size, which we found to be associated with mean ornament expression in sons. Our results are consistent with the idea that maternal effects can shape sexual selection by altering the genotype-phenotype relationship for ornamentation. They also caution against automatically attributing greater offspring attractiveness or viability to an extra-pair mate's superior genetic quality, as without controlling for differential maternal investment we may significantly overestimate the role of genetic benefits in the evolution of extra-pair mating behaviour.

BAYESIAN ANALYSIS FOR THE PAIRED COMPARISON MODEL WITH ORDER EFFECTS (USING NON-INFORMATIVE PRIORS

Directory of Open Access Journals (Sweden)

Ghausia Masood Gilani

2008-07-01

Full Text Available Sometimes it may be difficult for a panelist to rank or compare more than two objects or treatments at the same time. For this reason, paired comparison method is used. In this study, the Davidson and Beaver (1977 model for paired comparisons with order effects is analyzed through the Bayesian Approach. For this purpose, the posterior means and the posterior modes are compared using the noninformative priors.

Finite size and dynamical effects in pair production by an external field

International Nuclear Information System (INIS)

Martin, C.; Vautherin, D.

1988-12-01

We evaluate the rate of pair production in a uniform electric field confined into a bounded region in space. Using the Balian-Bloch expansion of Green's functions we obtain explicit expressions for finite size corrections to Schwinger's formula. The case of a time-dependent boundary, relevant to describe energy deposition by quark-antiquark pair production in ultrarelativistic collisions, is also investigated. We find that finite size effects are important in nuclear collisions. They decrease when the strength of the chromo-electric field between the nuclei is large. As a result, the rate of energy deposition increases sharply with the mass number A of the colliding nuclei

Na Cl ion pair association in water-DMSO mixtures: Effect of ion pair ...

Indian Academy of Sciences (India)

The 12-6-1 potential model predicts running coordination numbers closest to experimental data. Keywords. ... value of interaction energy minimum between the Na. + and Cl. − ..... ion pair mostly remains as a CIP, a fair amount of SAIP is also ...

Image-Word Pairing-Congruity Effect on Affective Responses

Science.gov (United States)

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.

Neutron pair and proton pair transfer reactions between identical cores in the sulfur region

International Nuclear Information System (INIS)

Mermaz, M.C.

1995-12-01

Optical model and exact finite range distorted-wave Born approximation analyses were performed on neutron pair exchange between identical cores for 32 S and 34 S nuclei and on proton pair exchange between identical cores for 30 Si and 32 S. The extracted spectroscopic factors were compared with theoretical ones deduced from Hartree-Fock calculations on these pair of nuclei. The enhancement of the experimental cross sections with respect to the theoretical ones strongly suggests evidence for a nuclear Josephson effect. (author). 15 refs., 5 figs., 3 tabs

Collective neutrino-pair emission due to Cooper pairing of protons in superconducting neutron stars

International Nuclear Information System (INIS)

Leinson, L.B.

2001-01-01

The neutrino emission due to formation and breaking of Cooper pairs of protons in superconducting cores of neutron stars is considered with taking into account the electromagnetic coupling of protons to ambient electrons. It is shown that collective response of electrons to the proton quantum transition contributes coherently to the complete interaction with a neutrino field and enhances the neutrino-pair production. Our calculation shows that the contribution of the vector weak current to the ννbar emissivity of protons is much larger than that calculated by different authors without taking into account the plasma effects. Partial contribution of the pairing protons to the total neutrino radiation from the neutron star core is very sensitive to the critical temperatures for the proton and neutron pairing. We show domains of these parameters where the neutrino radiation, caused by a singlet-state pairing of protons is dominating

Determination of the pairing-strength constants in the isovector plus isoscalar pairing case

Science.gov (United States)

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.

Apomorphine conditioning and sensitization: the paired/unpaired treatment order as a new major determinant of drug conditioned and sensitization effects.

Science.gov (United States)

de Matos, Liana Wermelinger; Carey, Robert J; Carrera, Marinete Pinheiro

2010-09-01

Repeated treatments with psychostimulant drugs generate behavioral sensitization. In the present study we employed a paired/unpaired protocol to assess the effects of repeated apomorphine (2.0 mg/kg) treatments upon locomotion behavior. In the first experiment we assessed the effects of conditioning upon apomorphine sensitization. Neither the extinction of the conditioned response nor a counter-conditioning procedure in which we paired an inhibitory treatment (apomorphine 0.05 mg/kg) with the previously established conditioned stimulus modified the sensitization response. In the second experiment, we administered the paired/unpaired protocol in two phases. In the second phase, we reversed the paired/unpaired protocol. Following the first phase, the paired group alone exhibited conditioned locomotion in the vehicle test and a sensitization response. In the second phase, the initial unpaired group which received 5 paired apomorphine trials during the reversal phase did not develop a conditioned response but developed a potentiated sensitization response. This disassociation of the conditioned response from the sensitization response is attributed to an apomorphine anti-habituation effect that can generate a false positive Pavlovian conditioned response effect. The potentiated sensitization response induced by the treatment reversal protocol points to an important role for the sequential experience of the paired/unpaired protocol in behavioral sensitization. 2010 Elsevier Inc. All rights reserved.

Effect of pairing in nuclear level density at low temperatures

International Nuclear Information System (INIS)

Rhine Kumar, A.K.; Modi, Swati; Arumugam, P.

2013-01-01

The nuclear level density (NLD) has been an interesting topic for researchers, due its importance in many aspects of nuclear physics, nuclear astrophysics, nuclear medicine, and other applied areas. The calculation of NLD helps us to understand the energy distribution of the excited levels of nuclei, entropy, specific heat, reaction cross sections etc. In this work the effect of temperature and pairing on level-density of the nucleus 116 Sn has been studied

Functional and effective whole brain connectivity using magnetoencephalography to identify monozygotic twin pairs.

Science.gov (United States)

Demuru, M; Gouw, A A; Hillebrand, A; Stam, C J; van Dijk, B W; Scheltens, P; Tijms, B M; Konijnenberg, E; Ten Kate, M; den Braber, A; Smit, D J A; Boomsma, D I; Visser, P J

2017-08-29

Resting-state functional connectivity patterns are highly stable over time within subjects. This suggests that such 'functional fingerprints' may have strong genetic component. We investigated whether the functional (FC) or effective (EC) connectivity patterns of one monozygotic twin could be used to identify the co-twin among a larger sample and determined the overlap in functional fingerprints within monozygotic (MZ) twin pairs using resting state magnetoencephalography (MEG). We included 32 cognitively normal MZ twin pairs from the Netherlands Twin Register who participate in the EMIF-AD preclinAD study (average age 68 years). Combining EC information across multiple frequency bands we obtained an identification rate over 75%. Since MZ twin pairs are genetically identical these results suggest a high genetic contribution to MEG-based EC patterns, leading to large similarities in brain connectivity patterns between two individuals even after 60 years of life or more.

Effects of worked examples, example-problem, and problem-example pairs on novices’ learning

NARCIS (Netherlands)

Van Gog, Tamara; Kester, Liesbeth; Paas, Fred

2010-01-01

Van Gog, T., Kester, L., & Paas, F. (2011). Effects of worked examples, example-problem, and problem-example pairs on novices’ learning. Contemporary Educational Psychology, 36(3), 212-218. doi:10.1016/j.cedpsych.2010.10.004

Measuring Teacher Effectiveness through Hierarchical Linear Models: Exploring Predictors of Student Achievement and Truancy

Science.gov (United States)

Subedi, Bidya Raj; Reese, Nancy; Powell, Randy

2015-01-01

This study explored significant predictors of student's Grade Point Average (GPA) and truancy (days absent), and also determined teacher effectiveness based on proportion of variance explained at teacher level model. We employed a two-level hierarchical linear model (HLM) with student and teacher data at level-1 and level-2 models, respectively.…

Identification of Parton Pairs in a Dijet Event and Investigation of Its Effects on Dijet Resonance Search

Directory of Open Access Journals (Sweden)

Sertac Ozturk

2014-01-01

Full Text Available Being able to distinguish parton pair type in a dijet event could significantly improve the search for new particles that are predicted by the theories beyond the Standard Model at the Large Hadron Collider. To explore whether parton pair types manifesting themselves as a dijet event could be distinguished on an event-by-event basis, I performed a simulation based study considering observable jet variables. I found that using a multivariate approach can filter out about 80% of the other parton pairs while keeping more than half of the quark-quark or gluon-gluon parton pairs in an inclusive QCD dijet distribution. The effects of event-by-event parton pair tagging for dijet resonance searches were also investigated and I found that improvement on signal significance after applying parton pair tagging can reach up to 4 times for gluon-gluon resonances.

Evidence for pair correlation effects in heavy ion reactions

CERN Document Server

Auditore, L; D'Amico, V; De Pasquale, D; Trifiró, A; Trimarchi, M; Italiano, A

2003-01-01

The study of the sup 1 sup 2 C( sup 1 sup 4 N, sup 1 sup 4 N) sup 1 sup 2 C reaction was performed at 28 and 35 MeV beam energies. The results were analyzed in the frame of the EFRDWBA (Exact-Finite-Range Distorted Wave Born Approximation) assuming the simultaneous and sequential transfer of a np pair. The angular distributions, fairly reproduced in the first case, confirm the validity of the generalized BCS (Bardeen-Cooper-Schrieffer) theory to explain this behaviour. Moreover, this process could be regarded as a possible Nuclear Josephson Effect. (author)

Capturing pair-wise epistatic effects associated with three agronomic traits in barley.

Science.gov (United States)

Xu, Yi; Wu, Yajun; Wu, Jixiang

2018-04-01

Genetic association mapping has been widely applied to determine genetic markers favorably associated with a trait of interest and provide information for marker-assisted selection. Many association mapping studies commonly focus on main effects due to intolerable computing intensity. This study aims to select several sets of DNA markers with potential epistasis to maximize genetic variations of some key agronomic traits in barley. By doing so, we integrated a MDR (multifactor dimensionality reduction) method with a forward variable selection approach. This integrated approach was used to determine single nucleotide polymorphism pairs with epistasis effects associated with three agronomic traits: heading date, plant height, and grain yield in barley from the barley Coordinated Agricultural Project. Our results showed that four, seven, and five SNP pairs accounted for 51.06, 45.66 and 40.42% for heading date, plant height, and grain yield, respectively with epistasis being considered, while corresponding contributions to these three traits were 45.32, 31.39, 31.31%, respectively without epistasis being included. The results suggested that epistasis model was more effective than non-epistasis model in this study and can be more preferred for other applications.

Neutron roton pairing effect on some even ven rare-earth proton-rich nuclei

International Nuclear Information System (INIS)

Mokhtari, D.

2004-01-01

The neutron roton pairing effect on some even ven rare-earth proton-rich nuclei is studied. It is taken into account, in the isovector case, within the framework of the generalized Bogoliubov-Valatin transformation, using Woods-Saxon single-particle energies. (author)

Combining automatic table classification and relationship extraction in extracting anticancer drug-side effect pairs from full-text articles.

Science.gov (United States)

Xu, Rong; Wang, QuanQiu

2015-02-01

Anticancer drug-associated side effect knowledge often exists in multiple heterogeneous and complementary data sources. A comprehensive anticancer drug-side effect (drug-SE) relationship knowledge base is important for computation-based drug target discovery, drug toxicity predication and drug repositioning. In this study, we present a two-step approach by combining table classification and relationship extraction to extract drug-SE pairs from a large number of high-profile oncological full-text articles. The data consists of 31,255 tables downloaded from the Journal of Oncology (JCO). We first trained a statistical classifier to classify tables into SE-related and -unrelated categories. We then extracted drug-SE pairs from SE-related tables. We compared drug side effect knowledge extracted from JCO tables to that derived from FDA drug labels. Finally, we systematically analyzed relationships between anti-cancer drug-associated side effects and drug-associated gene targets, metabolism genes, and disease indications. The statistical table classifier is effective in classifying tables into SE-related and -unrelated (precision: 0.711; recall: 0.941; F1: 0.810). We extracted a total of 26,918 drug-SE pairs from SE-related tables with a precision of 0.605, a recall of 0.460, and a F1 of 0.520. Drug-SE pairs extracted from JCO tables is largely complementary to those derived from FDA drug labels; as many as 84.7% of the pairs extracted from JCO tables have not been included a side effect database constructed from FDA drug labels. Side effects associated with anticancer drugs positively correlate with drug target genes, drug metabolism genes, and disease indications. Copyright © 2014 Elsevier Inc. All rights reserved.

Magnetized pair Bose gas: relativistic superconductor

International Nuclear Information System (INIS)

Daicic, J.; Frankel, N.E.; Kowalenko, V.

1993-01-01

The magnetized Bose gas at temperatures above pair threshold is investigated. New magnetization laws are obtained for a wide range of field strengths, and the gas is shown to exhibit the Meissner effect. Some related results for the Fermi gas, a relativistic paramagnet, are also discussed. It is concluded that the pair gases, through the interplay between pair creation, temperature, field strength, statistics and/in the case of fermions/spin, have remarkable magnetic properties. 14 refs

Hadronic production of massive lepton pairs

International Nuclear Information System (INIS)

Berger, E.L.

1982-12-01

A review is presented of recent experimental and theoretical progress in studies of the production of massive lepton pairs in hadronic collisions. I begin with the classical Drell-Yan annihilation model and its predictions. Subsequently, I discuss deviations from scaling, the status of the proofs of factorization in the parton model, higher-order terms in the perturbative QCD expansion, the discrepancy between measured and predicted yields (K factor), high-twist terms, soft gluon effects, transverse-momentum distributions, implications for weak vector boson (W +- and Z 0 ) yields and production properties, nuclear A dependence effects, correlations of the lepton pair with hadrons in the final state, and angular distributions in the lepton-pair rest frame

Hole pairing induced by antiferromagnetic spin fluctuations

International Nuclear Information System (INIS)

Su, Z.B.; Yu Lu; Dong, J.M.; Tosatti, E.

1987-08-01

The effective interaction induced by antiferromagnetic spin fluctuations is considered in the random phase approximation in the context of the recently discovered high T c oxide superconductors. This effective attraction favours a triplet pairing of holes. The implications of such pairing mechanism are discussed in connection with the current experimental observations. (author). 30 refs, 2 figs

Radical-pair based avian magnetoreception

Science.gov (United States)

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.

Effects of pairing correlation on low-lying quasi-particle resonance in neutron drip-line nuclei

OpenAIRE

Kobayashi, Yoshihiko; Matsuo, Masayuki

2015-01-01

We discuss effects of pairing correlation on quasi-particle resonance. We analyze in detail how the width of low-lying quasi-particle resonance is governed by the pairing correlation in the neutron drip-line nuclei. We consider the 46Si + n system to discuss low-lying p wave quasi-particle resonance. Solving the Hartree-Fock-Bogoliubov equation in the coordinate space with scattering boundary condition, we calculate the phase shift, the elastic cross section, the resonance width and the reson...

Higgs boson pair production at NNLO with top quark mass effects

Science.gov (United States)

Grazzini, M.; Heinrich, G.; Jones, S.; Kallweit, S.; Kerner, M.; Lindert, J. M.; Mazzitelli, J.

2018-05-01

We consider QCD radiative corrections to Higgs boson pair production through gluon fusion in proton collisions. We combine the exact next-to-leading order (NLO) contribution, which features two-loop virtual amplitudes with the full dependence on the top quark mass M t , with the next-to-next-to-leading order (NNLO) corrections computed in the large- M t approximation. The latter are improved with different reweighting techniques in order to account for finite- M t effects beyond NLO. Our reference NNLO result is obtained by combining one-loop double-real corrections with full M t dependence with suitably reweighted real-virtual and double-virtual contributions evaluated in the large- M t approximation. We present predictions for inclusive cross sections in pp collisions at √{s} = 13, 14, 27 and 100 TeV and we discuss their uncertainties due to missing M t effects. Our approximated NNLO corrections increase the NLO result by an amount ranging from +12% at √{s}=13 TeV to +7% at √{s}=100 TeV, and the residual uncertainty of the inclusive cross section from missing M t effects is estimated to be at the few percent level. Our calculation is fully differential in the Higgs boson pair and the associated jet activity: we also present predictions for various differential distributions at √{s}=14 and 100 TeV, and discuss the size of the missing M t effects, which can be larger, especially in the tails of certain observables. Our results represent the most advanced perturbative prediction available to date for this process.

On the pair creation effect in radiative bottonium transitions

International Nuclear Information System (INIS)

Lewin, K.; Motz, G.B.

1986-01-01

The contributions from internal b-quark pair creation to the radiative transition rates of the processes Y(2S) → X b 1 +γ and X b 2 → Y(1S)+γ have been estimated in a quasilocal approximation preserving the time-dependence of the antiquark propagator and found to be smaller than 10%. Although relatively small, the pair creation correction depends sensitively on quark masses and photon energies and thus cannot be ignored in quantitative investigations of radiative quarkonium transitions

String pair production in non homogeneous backgrounds

Energy Technology Data Exchange (ETDEWEB)

Bolognesi, S. [Department of Physics “E. Fermi” University of Pisa, and INFN - Sezione di Pisa,Largo Pontecorvo, 3, Ed. C, 56127 Pisa (Italy); Rabinovici, E. [Racah Institute of Physics, The Hebrew University of Jerusalem,91904 Jerusalem (Israel); Tallarita, G. [Departamento de Ciencias, Facultad de Artes Liberales,Universidad Adolfo Ibáñez, Santiago 7941169 (Chile)

2016-04-28

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.

String pair production in non homogeneous backgrounds

International Nuclear Information System (INIS)

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

2016-01-01

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.

Comparative Analysis of Compatibility Effects on Invigorating Blood Circulation for Cyperi Rhizoma Series of Herb Pairs Using Untargeted Metabolomics

Directory of Open Access Journals (Sweden)

Pei Liu

2017-09-01

Full Text Available The mutual-assistance compatibility of Cyperi Rhizoma (Xiangfu, XF and Angelicae Sinensis Radix (Danggui, DG, Chuanxiong Rhizoma (Chuanxiong, CX, Paeoniae Radix Alba (Baishao, BS, or Corydalis Rhizoma (Yanhusuo, YH, found in a traditional Chinese medicine (TCM named Xiang-Fu-Si-Wu Decoction (XFSWD, can produce synergistic and promoting blood effects. Nowadays, XFSWD has been proved to be effective in activating blood circulation and dissipating blood stasis. However, the role of the herb pairs synergistic effects in the formula were poorly understood. In order to quantitatively assess the compatibility effects of herb pairs, mass spectrometry-based untargeted metabolomics studies were performed. The plasma and urine metabolic profiles of acute blood stasis rats induced by adrenaline hydrochloride and ice water and administered with Cyperi Rhizoma—Angelicae Sinensis Radix (XD, Cyperi Rhizoma—Chuanxiong Rhizoma (XC, Cyperi Rhizoma—Paeoniae Radix Alba (XB, Cyperi Rhizoma—Corydalis Rhizoma (XY were compared. Relative peak area of identified metabolites was calculated and principal component analysis (PCA score plot from the potential markers was used to visualize the overall differences. Then, the metabolites results were used with biochemistry indicators and genes expression values as parameters to quantitatively evaluate the compatibility effects of XF series of herb pairs by PCA and correlation analysis. The collective results indicated that the four XF herb pairs regulated glycerophospholipid metabolism, steroid hormone biosynthesis and arachidonic acid metabolism pathway. XD was more prominent in regulating the blood stasis during the four XF herb pairs. This study demonstrated that metabolomics was a useful tool to efficacy evaluation and compatibility effects of TCM elucidation.

Measuring the Effects of Virtual Pair Programming in an Introductory Programming Java Course

Science.gov (United States)

Zacharis, N. Z.

2011-01-01

This study investigated the effectiveness of virtual pair programming (VPP) on student performance and satisfaction in an introductory Java course. Students used online tools that integrated desktop sharing and real-time communication, and the metrics examined showed that VPP is an acceptable alternative to individual programming experience.…

Pairing fluctuations in trapped Fermi gases

International Nuclear Information System (INIS)

Viverit, Luciano; Bruun, Georg M.; Minguzzi, Anna; Fazio, Rosario

2004-01-01

We examine the contribution of pairing fluctuations to the superfluid order parameter for harmonically trapped atomic Fermi gases in the BCS regime. In the limit of small systems we consider, both analytically and numerically, their space and temperature dependence. We predict a parity effect, i.e., that pairing fluctuations show a maximum or a minimum at the center of the trap, depending on the value of the last occupied shell being even or odd. We propose to detect pairing fluctuations by measuring the density-density correlation function after a ballistic expansion of the gas

Pair shell model description of collective motions

International Nuclear Information System (INIS)

Chen Hsitseng; Feng Dahsuan

1996-01-01

The shell model in the pair basis has been reviewed with a case study of four particles in a spherical single-j shell. By analyzing the wave functions according to their pair components, the novel concept of the optimum pairs was developed which led to the proposal of a generalized pair mean-field method to solve the many-body problem. The salient feature of the method is its ability to handle within the framework of the spherical shell model a rotational system where the usual strong configuration mixing complexity is so simplified that it is now possible to obtain analytically the band head energies and the moments of inertia. We have also examined the effects of pair truncation on rotation and found the slow convergence of adding higher spin pairs. Finally, we found that when the SDI and Q .Q interactions are of equal strengths, the optimum pair approximation is still valid. (orig.)

Coherent pair creation from beam-beam interaction

International Nuclear Information System (INIS)

Chen, Pisin.

1989-09-01

It has recently been recognized that in future linear colliders, there is a finite probability that the beamstrahlung photons will turn into e + e - pairs induced by the same beam-beam field, and this would potentially cause background problems. In this paper, we first review the probability of such a coherent pair creation process. It is seen that the constraint on the beamstrahlung parameter, Υ, is tight of these coherent pairs to be totally suppressed. We then point out that there exists a minimum energy for the pair-created particles, which scales as ∼1/5Υ. When combining this condition with the deflection angle for the low-energy particles, the constraint on the allowable Υ value is much relaxed. Finally, we calculate the effective cross section for producing the weak bosons by the low-energy e + e - pairs. It is shown that these cross sections are substantial for Υ > 1. We suggest that this effect can help to autoscan the particle spectrum in the high energy frontier. 10 refs., 2 figs

Effects of ion pairs on the dynamics of erbium doped fiber laser in the inhomogeneous model

International Nuclear Information System (INIS)

Keyvaninia, Sh.; Karvar, M.; Bahrampour, A.

2006-01-01

In a high concentration erbium doped fiber, the erbium ions are so closed together that the ion pairs and clusters are formed. In such fiber amplifiers, the ion pairs and clusters acting as a saturable absorber are distributed along the fiber laser. The inhomogeneous rate equations for the laser modes in a high-concentration EDFA are written. The governing equations are an uncountable system of partial differential equations. For the first time we introduced an approximation method that the system of partial differential equations is converted to a finite system of ordinary differential equations. The effects of ion pairs concentration on erbium doped fiber are analyzed that is in good agreement whit the experimental result.

Electron-positron pair production in inhomogeneous electromagnetic fields

International Nuclear Information System (INIS)

Kohlfürst, C.

2015-01-01

The process of electron-positron pair production is investigated within the phase-space Wigner formalism. The similarities between atomic ionization and pair production for homogeneous, but time-dependent linearly polarized electric fields are examined mainly in the regime of multiphoton absorption (field-dependent threshold, above-threshold pair production). Characteristic signatures in the particle spectra are identified (effective mass, channel closing). The non-monotonic dependence of the particle yield on the carrier frequency is discussed as well. The investigations are then extended to spatially inhomogeneous electric fields. New effects arising due to the spatial dependence of the effective mass are discussed in terms of a semi-classical interpretation. An increase in the normalized particle yield is found for various field configurations.Pair production in inhomogeneous electric and magnetic fields is also studied. The influence of a time-dependent spatially inhomogeneous magnetic field on the momentum spectrum and the particle yield is investigated. The Lorentz invariants are identified to be crucial in order to understand pair production by strong electric fields in the presence of strong magnetic fields. (author) [de

Influence of quadrupole pairing on backbending

International Nuclear Information System (INIS)

Faessler, A.; Wakai, M.

1978-01-01

The backbending phenomenon is attributed to the Coriolis antipairing and the rotational alignment effects. We can consider both effects simultaneously by applying the cranked Hartree-Fock-Bogoliubov theory to the description of the rotational motion of nuclei. In usual treatments of the backbending, however, only the monopole pairing force is considered and pairing forces of other types are neglected. This may be the main reason for starting of the backbending at too small total angular momentum in theoretical results. (orig.) [de

Dual origin of pairing in nuclei

Energy Technology Data Exchange (ETDEWEB)

Idini, A. [University of Jyvaskyla, Department of Physics (Finland); Potel, G. [Michigan State University, National Superconducting Cyclotron Laboratory (United States); Barranco, F. [Escuela Superior de Ingenieros, Universidad de Sevilla, Departamento de Fìsica Aplicada III (Spain); Vigezzi, E., E-mail: enrico.vigezzi@mi.infn.it [INFN Sezione di Milano (Italy); Broglia, R. A. [Università di Milano, Dipartimento di Fisica (Italy)

2016-11-15

The pairing correlations of the nucleus {sup 120}Sn are calculated by solving the Nambu–Gor’kov equations, including medium polarization effects resulting from the interweaving of quasiparticles, spin and density vibrations, taking into account, within the framework of nuclear field theory (NFT), processes leading to self-energy and vertex corrections and to the induced pairing interaction. From these results one can not only demonstrate the inevitability of the dual origin of pairing in nuclei, but also extract information which can be used at profit to quantitatively disentangle the contributions to the pairing gap Δ arising from the bare and from the induced pairing interaction. The first is the strong {sup 1}S{sub 0} short-range NN potential resulting from meson exchange between nucleons moving in time reversal states within an energy range of hundreds of MeV from the Fermi energy. The second results from the exchange of vibrational modes between nucleons moving within few MeV from the Fermi energy. Short- (v{sub p}{sup bare}) and long-range (v{sub p}{sup ind}) pairing interactions contribute essentially equally to nuclear Cooper pair stability. That is to the breaking of gauge invariance in open-shell superfluid nuclei and thus to the order parameter, namely to the ground state expectation value of the pair creation operator. In other words, to the emergent property of generalized rigidity in gauge space, and associated rotational bands and Cooper pair tunneling between members of these bands.

Dual origin of pairing in nuclei

Science.gov (United States)

Idini, A.; Potel, G.; Barranco, F.; Vigezzi, E.; Broglia, R. A.

2016-11-01

The pairing correlations of the nucleus 120Sn are calculated by solving the Nambu-Gor'kov equations, including medium polarization effects resulting from the interweaving of quasiparticles, spin and density vibrations, taking into account, within the framework of nuclear field theory (NFT), processes leading to self-energy and vertex corrections and to the induced pairing interaction. From these results one can not only demonstrate the inevitability of the dual origin of pairing in nuclei, but also extract information which can be used at profit to quantitatively disentangle the contributions to the pairing gap Δ arising from the bare and from the induced pairing interaction. The first is the strong 1 S 0 short-range NN potential resulting from meson exchange between nucleons moving in time reversal states within an energy range of hundreds of MeV from the Fermi energy. The second results from the exchange of vibrational modes between nucleons moving within few MeV from the Fermi energy. Short- ( v p bare) and long-range ( v p ind) pairing interactions contribute essentially equally to nuclear Cooper pair stability. That is to the breaking of gauge invariance in open-shell superfluid nuclei and thus to the order parameter, namely to the ground state expectation value of the pair creation operator. In other words, to the emergent property of generalized rigidity in gauge space, and associated rotational bands and Cooper pair tunneling between members of these bands.

Hydration of Watson-Crick base pairs and dehydration of Hoogsteen base pairs inducing structural polymorphism under molecular crowding conditions.

Science.gov (United States)

Miyoshi, Daisuke; Nakamura, Kaori; Tateishi-Karimata, Hisae; Ohmichi, Tatsuo; Sugimoto, Naoki

2009-03-18

It has been revealed recently that molecular crowding, which is one of the largest differences between in vivo and in vitro conditions, is a critical factor determining the structure, stability, and function of nucleic acids. However, the effects of molecular crowding on Watson-Crick and Hoogsteen base pairs remain unclear. In order to investigate directly and quantitatively the molecular crowding effects on base pair types in nucleic acids, we designed intramolecular parallel- and antiparallel-stranded DNA duplexes consisting of Hoogsteen and Watson-Crick base pairs, respectively, as well as an intramolecular parallel-stranded triplex containing both types of base pairs. Thermodynamic analyses demonstrated that the values of free energy change at 25 degrees C for Hoogsteen base-pair formations decreased from +1.45 +/- 0.15 to +1.09 +/- 0.13 kcal mol(-1), and from -1.89 +/- 0.13 to -2.71 +/- 0.11 kcal mol(-1) in the intramolecular duplex and triplex, respectively, when the concentration of PEG 200 (polyethylene glycol with average molecular weight 200) increased from 0 to 20 wt %. However, corresponding values for Watson-Crick formation in the duplex and triplex increased from -10.2 +/- 0.2 to -8.7 +/- 0.1 kcal mol(-1), and from -10.8 +/- 0.2 to -9.2 +/- 0.2 kcal mol(-1), respectively. Furthermore, it was revealed that the opposing effects of molecular crowding on the Hoogsteen and Watson-Crick base pairs were due to different behaviors of water molecules binding to the DNA strands.

All paired up with no place to go: pairing, synapsis, and DSB formation in a balancer heterozygote.

Directory of Open Access Journals (Sweden)

Wei J Gong

2005-11-01

Full Text Available The multiply inverted X chromosome balancer FM7 strongly suppresses, or eliminates, the occurrence of crossing over when heterozygous with a normal sequence homolog. We have utilized the LacI-GFP: lacO system to visualize the effects of FM7 on meiotic pairing, synapsis, and double-strand break formation in Drosophila oocytes. Surprisingly, the analysis of meiotic pairing and synapsis for three lacO reporter couplets in FM7/X heterozygotes revealed they are paired and synapsed during zygotene/pachytene in 70%-80% of oocytes. Moreover, the regions defined by these lacO couplets undergo double-strand break formation at normal frequency. Thus, even complex aberration heterozygotes usually allow high frequencies of meiotic pairing, synapsis, and double-strand break formation in Drosophila oocytes. However, the frequencies of failed pairing and synapsis were still 1.5- to 2-fold higher than were observed for corresponding regions in oocytes with two normal sequence X chromosomes, and this effect was greatest near a breakpoint. We propose that heterozygosity for breakpoints creates a local alteration in synaptonemal complex structure that is propagated across long regions of the bivalent in a fashion analogous to chiasma interference, which also acts to suppress crossing over.

Generalized pairing strategies-a bridge from pairing strategies to colorings

Directory of Open Access Journals (Sweden)

Győrffy Lajos

2016-12-01

Full Text Available In this paper we define a bridge between pairings and colorings of the hypergraphs by introducing a generalization of pairs called t-cakes for t ∈ ℕ, t ≥ 2. For t = 2 the 2-cakes are the same as the well-known pairs of system of distinct representatives, that can be turned to pairing strategies in Maker-Breaker hypergraph games, see Hales and Jewett [12]. The two-colorings are the other extremity of t-cakes, in which the whole ground set of the hypergraph is one big cake that we divide into two parts (color classes. Starting from the pairings (2-cake placement and two-colorings we define the generalized t-cake placements where we pair p elements by q elements (p, q ∈ ℕ, 1 ≤ p, q < t, p + q = t.

Dependence between the colour of galaxies in pairs (Holmberg effect)

International Nuclear Information System (INIS)

Demin, V.V.; Zasov, A.V.; Dibaj, Eh.A.; Tomov, A.N.

1984-01-01

Proceeding from the data of photoelectric photometpy by Tomov, the colours of galaxies in double systems are studied For the most of the paips formed by elliptical (EE) or by spiral (SS) galaxies, the difference between the corrected colour indices (B-V)sub(T)sup(0) of components does not exceed 0.10 and does not depend on the difference ΔT of their morphological types The correlation between the colours of galaxies in EE-pairs can be explained by the similaritins of element abundances but not of the luminosities of galaxies. The elliptical and SO-galaxies in pairs with the spiral galaxies ape noticeably bluep on the avepage. The relation between the colours of galaxies in ES-pairs is possible. The colours of early-type spiral galaxies (T < 4) in most of the SS-systems are more blue as compared to the mean colours of galaxies of the same type T. A similarity of the colours of the galaxies in many of the SS-pairs can be a result of the periodically repeated bursts of star formation which take place in both galaxies simultaneously

Pairing Learners by Companionship: Effects on Motor Skill Performance and Comfort Levels in the Reciprocal Style of Teaching

Science.gov (United States)

Chatoupis, Constantine

2015-01-01

Mosston and Ashworth's (2008) reciprocal style of teaching gives learners the opportunity to work in pairs to support each other's learning (one practices a task and the other gives feedback). The effects of pairing learners by companionship (friend and nonacquaintance) on 8-year-old children's motor skill performance and comfort levels were…

HAL-2 promotes homologous pairing during Caenorhabditis elegans meiosis by antagonizing inhibitory effects of synaptonemal complex precursors.

Science.gov (United States)

Zhang, Weibin; Miley, Natasha; Zastrow, Michael S; MacQueen, Amy J; Sato, Aya; Nabeshima, Kentaro; Martinez-Perez, Enrique; Mlynarczyk-Evans, Susanna; Carlton, Peter M; Villeneuve, Anne M

2012-01-01

During meiosis, chromosomes align with their homologous pairing partners and stabilize this alignment through assembly of the synaptonemal complex (SC). Since the SC assembles cooperatively yet is indifferent to homology, pairing and SC assembly must be tightly coordinated. We identify HAL-2 as a key mediator in this coordination, showing that HAL-2 promotes pairing largely by preventing detrimental effects of SC precursors (SYP proteins). hal-2 mutants fail to establish pairing and lack multiple markers of chromosome movement mediated by pairing centers (PCs), chromosome sites that link chromosomes to cytoplasmic microtubules through nuclear envelope-spanning complexes. Moreover, SYP proteins load inappropriately along individual unpaired chromosomes in hal-2 mutants, and markers of PC-dependent movement and function are restored in hal-2; syp double mutants. These and other data indicate that SYP proteins can impede pairing and that HAL-2 promotes pairing predominantly but not exclusively by counteracting this inhibition, thereby enabling activation and regulation of PC function. HAL-2 concentrates in the germ cell nucleoplasm and colocalizes with SYP proteins in nuclear aggregates when SC assembly is prevented. We propose that HAL-2 functions to shepherd SYP proteins prior to licensing of SC assembly, preventing untimely interactions between SC precursors and chromosomes and allowing sufficient accumulation of precursors for rapid cooperative assembly upon homology verification.

Effects of exogenous polyamines and inhibitors of polyamine ...

African Journals Online (AJOL)

guanylhydrazone) (MGBG) and dicyclohexylamine (DCHA) or three exogenous polyamines (putrescine, spermidine and spermine) were added into a modified HLM-1 maturation medium inoculated with embryogenic tissues. Medium responses were ...

Pair production in small angle Bhabha scattering

International Nuclear Information System (INIS)

Arbuzov, A.B.; Kuraev, Eh.A.; Merenkov, N.P.; Trentadue, L.

1995-01-01

The radiative corrections due to a pair production in the small angle high energy e + e - Bhabha scattering are considered. The corrections due to the production of virtual pairs as well as real soft and hard ones are calculated analytically. The collinear and semi-collinear kinematical regions of the hard pair production are taken into account. The results in the leading and next-to-leading logarithmic approximations provide the accuracy of Ο (0.1%). The results of numerical calculations show that the effects of pairs production are to be taken into account in the precise luminosity determination at LEP. 9 refs., 3 figs., 2 tabs

Studies of base pair sequence effects on DNA solvation based on all-atom molecular dynamics simulations.

Science.gov (United States)

Dixit, Surjit B; Mezei, Mihaly; Beveridge, David L

2012-07-01

Detailed analyses of the sequence-dependent solvation and ion atmosphere of DNA are presented based on molecular dynamics (MD) simulations on all the 136 unique tetranucleotide steps obtained by the ABC consortium using the AMBER suite of programs. Significant sequence effects on solvation and ion localization were observed in these simulations. The results were compared to essentially all known experimental data on the subject. Proximity analysis was employed to highlight the sequence dependent differences in solvation and ion localization properties in the grooves of DNA. Comparison of the MD-calculated DNA structure with canonical A- and B-forms supports the idea that the G/C-rich sequences are closer to canonical A- than B-form structures, while the reverse is true for the poly A sequences, with the exception of the alternating ATAT sequence. Analysis of hydration density maps reveals that the flexibility of solute molecule has a significant effect on the nature of observed hydration. Energetic analysis of solute-solvent interactions based on proximity analysis of solvent reveals that the GC or CG base pairs interact more strongly with water molecules in the minor groove of DNA that the AT or TA base pairs, while the interactions of the AT or TA pairs in the major groove are stronger than those of the GC or CG pairs. Computation of solvent-accessible surface area of the nucleotide units in the simulated trajectories reveals that the similarity with results derived from analysis of a database of crystallographic structures is excellent. The MD trajectories tend to follow Manning's counterion condensation theory, presenting a region of condensed counterions within a radius of about 17 A from the DNA surface independent of sequence. The GC and CG pairs tend to associate with cations in the major groove of the DNA structure to a greater extent than the AT and TA pairs. Cation association is more frequent in the minor groove of AT than the GC pairs. In general, the

The effect of endoscopic sterilization on reproductive behavior and pair bond maintenance of feral pigeons (Columba livia).

Science.gov (United States)

Heiderich, E; Failing, K; Lierz, M; Schildger, B

2016-01-01

Problems related to feral pigeons (Columba livia) in cities mainly result from their large numbers due to uncontrolled population growth. The aim of this study was to evaluate whether endoscopic guided sterilization affects the reproductive behavior of feral pigeons under experimental conditions, with the intention of assessing this technique as a potential method for feral pigeon population control. Five groups of four pairs of feral pigeons each were studied from 8 weeks before, to 7 weeks after sterilization. Both the male and female of the first pair of each group were sterilized, in the second pair only the female and in the third pair only the male was sterilized. The fourth pair acted as a control. All eggs laid were candled to assess fertility. Surgical sterilization had minimal effects on behavior and therefore seems not to have impact on possible field application for population control. All pairs maintained their pair bonds and continued to defend their nesting sites against other pigeons. Only one female copulated with a foreign fertile male while her primary partner was debilitated due to surgery, but returned to him as soon as he recovered. All eggs laid more than 5 days after male sterilization were infertile, whereas all control pairs had fertile eggs. Only one fertile clutch was produced, 5 days after the male's sterilization. Therefore it is assumed that males remain fertile for a limited period of time. Endoscopic sterilization seems to be a promising method for field control of feral pigeon populations and sterilization of the male only seems sufficient.

Pair creation by dynamic field configurations

International Nuclear Information System (INIS)

Aoyama, H.

1982-01-01

This thesis deals with the dynamics of the classical configuration of a quantum field unstable due to pair creation. The effective action method is developed first to treat such problems for a simple two-field model. Physical quantities such as pair creation probabilities are related to a complex function called the effective configuration, which is defined to minimize the effective action. Unitarity of the S-matrix is verified at the lowest order of the weak-field approximation. At the same order, the real valued vacuum expectation value of the quantum field, named the real configuration, is constructed in terms of the effective configuration. An integro-differential equation for the real configuration is given and is used to show that the real configuration is causal, while the effective configuration is not. Two practical applications of the effective action method are discussed. The first deals with pair creation in an anisotropic universe, and the real geometry is given in terms of the effective geometry in the samll anisotropy limit. The second deals with expanding vacuum bubbles. Corresponding to three possible situations, three kinds of field equations of each of the effective configuration and the real configuration are obtained. The behavior of the bubble is also studied by a semi-classical method, and one of the three situations is suggested to be plausible

Inflation of the screening length induced by Bjerrum pairs.

Science.gov (United States)

Zwanikken, Jos; van Roij, René

2009-10-21

Within a modified Poisson-Boltzmann theory we study the effect of Bjerrum pairs on the typical length scale [Formula: see text] over which electric fields are screened in electrolyte solutions, taking into account a simple association-dissociation equilibrium between free ions and Bjerrum pairs. At low densities of Bjerrum pairs, this length scale is well approximated by the Debye length [Formula: see text], with ρ(s) the free-ion density. At high densities of Bjerrum pairs, however, we find [Formula: see text], which is significantly larger than 1/κ due to the enhanced effective permittivity of the electrolyte, caused by the polarization of Bjerrum pairs. We argue that this mechanism may explain the recently observed anomalously large colloid-free zones between an oil-dispersed colloidal crystal and a colloidal monolayer at the oil-water interface.

Competition between Final-State and Pairing-Gap Effects in the Radio-Frequency Spectra of Ultracold Fermi Atoms

International Nuclear Information System (INIS)

Perali, A.; Pieri, P.; Strinati, G. C.

2008-01-01

The radio-frequency spectra of ultracold Fermi atoms are calculated by including final-state interactions affecting the excited level of the transition and compared with the experimental data. A competition is revealed between pairing-gap effects which tend to push the oscillator strength toward high frequencies away from threshold and final-state effects which tend instead to pull the oscillator strength toward threshold. As a result of this competition, the position of the peak of the spectra cannot be simply related to the value of the pairing gap, whose extraction thus requires support from theoretical calculations

English for au pairs the au pair's guide to learning English

CERN Document Server

Curtis, Lucy

2014-01-01

English for Au Pairs has interlinked stories about a group of au pairs new to England. Marta, an 18-year-old from Poland arrives in the UK to work as an au pair. Throughout her year-long stay she has many different experiences - some bad, some good - but with the support of her host family she finds new friends and improves her English. English for Au Pairs offers insight into the joys and difficulties of being an au pair while at the same time reinforcing English language learning through grammar explanations and exercises.

Thermogalvanic corrosion and galvanic effects of copper and AISI 316L stainless steel pairs in heavy LiBr brines under hydrodynamic conditions

International Nuclear Information System (INIS)

Sánchez-Tovar, R.; Montañés, M.T.; García-Antón, J.

2012-01-01

Highlights: ► Thermogalvanic corrosion results in an increase of the current densities. ► Thermogalvanic effect increases as temperature difference between tubes is higher. ► Potentials fit linearly with increase in temperature. ► ZRA shows hot cathodes for AISI 316L while cold ones for copper and galvanic pairs. ► Weight loss tests show a combined effect between thermogalvanic and galvanic effects. - Abstract: Thermogalvanic corrosion of the copper/copper and AISI 316L/AISI 316L stainless steel pairs was studied in heavy lithium bromide brines under hydrodynamic conditions. The galvanic coupling effect between copper and stainless steel was also analysed. The cold electrode (25 °C) was the stainless steel for the galvanic pair, whereas copper temperature varied (25, 50 and 75 °C). A hydrodynamic circuit was designed to study thermogalvanic corrosion by means of the zero resistance ammeter technique. Hot cathodes take place in stainless steel pairs while cold cathodes are present in copper/copper and stainless steel/copper pairs; this agrees with the thermal temperature coefficient of the potential sign. Thermogalvanic corrosion increases corrosion rates, especially working with copper. Weight loss measurements show that there is a combined effect due to the thermogalvanic and the galvanic effects.

Implications of the effective one-component analysis of pair correlations in colloidal fluids with polydispersity

Science.gov (United States)

Pond, Mark J.; Errington, Jeffrey R.; Truskett, Thomas M.

2011-09-01

Partial pair-correlation functions of colloidal suspensions with continuous polydispersity can be challenging to characterize from optical microscopy or computer simulation data due to inadequate sampling. As a result, it is common to adopt an effective one-component description of the structure that ignores the differences between particle types. Unfortunately, whether this kind of simplified description preserves or averages out information important for understanding the behavior of the fluid depends on the degree of polydispersity and can be difficult to assess, especially when the corresponding multicomponent description of the pair correlations is unavailable for comparison. Here, we present a computer simulation study that examines the implications of adopting an effective one-component structural description of a polydisperse fluid. The square-well model that we investigate mimics key aspects of the experimental behavior of suspended colloids with short-range, polymer-mediated attractions. To characterize the partial pair-correlation functions and thermodynamic excess entropy of this system, we introduce a Monte Carlo sampling strategy appropriate for fluids with a large number of pseudo-components. The data from our simulations at high particle concentrations, as well as exact theoretical results for dilute systems, show how qualitatively different trends between structural order and particle attractions emerge from the multicomponent and effective one-component treatments, even with systems characterized by moderate polydispersity. We examine consequences of these differences for excess-entropy based scalings of shear viscosity, and we discuss how use of the multicomponent treatment reveals similarities between the corresponding dynamic scaling behaviors of attractive colloids and liquid water that the effective one-component analysis does not capture.

Deuterium isotope effects and fractionation factors of hydrogen-bonded A:T base pairs of DNA

International Nuclear Information System (INIS)

Vakonakis, Ioannis; Salazar, Miguel; Kang, Mijeong; Dunbar, Kim R.; Li Wang, Andy C.

2003-01-01

Deuterium isotope effects and fractionation factors of N1...H3-N3 hydrogen bonded Watson-Crick A:T base pairs of two DNA dodecamers are presented here. Specifically, two-bond deuterium isotope effects on the chemical shifts of 13 C2 and 13 C4, 2 Δ 13 C2 and 2 Δ 13 C4, and equilibrium deuterium/protium fractionation factors of H3, Φ, were measured and seen to correlate with the chemical shift of the corresponding imino proton, δ H3 . Downfield-shifted imino protons associated with larger values of 2 Δ 13 C2 and 2 Δ 13 C4 and smaller Φ values, which together suggested that the effective H3-N3 vibrational potentials were more anharmonic in the stronger hydrogen bonds of these DNA molecules. We anticipate that 2 Δ 13 C2, 2 Δ 13 C4 and Φ values can be useful gauges of hydrogen bond strength of A:T base pairs

The Effects of Performance Budgeting and Funding Programs on Graduation Rate in Public Four-Year Colleges and Universities

Directory of Open Access Journals (Sweden)

Jung-cheol Shinn

2004-05-01

Full Text Available This study was conducted to determine whether states with performance budgeting and funding (PBF programs had improved institutional performance of higher education over the five years (1997 through 2001 considered in this study. First Time in College (FTIC graduation rate was used as the measure of institutional performance. In this study, the unit of analysis is institution level and the study population is all public four-or-more-year institutions in the United States. To test PBF program effectiveness, Hierarchical Linear Modeling (HLM growth analysis was applied. According to the HLM analysis, the growth of graduation rates in states with PBF programs was not greater than in states without PBF programs. The lack of growth in institutional graduation rates, however, does not mean that PBF programs failed to achieve their goals. Policy-makers are advised to sustain PBF programs long enough until such programs bear their fruits or are proven ineffective.

Effect of base-pair inhomogeneities on charge transport along the DNA molecule, mediated by twist and radial polarons

International Nuclear Information System (INIS)

Palmero, F; Archilla, J F R; Hennig, D; Romero, F R

2004-01-01

Some recent results for a three-dimensional, semi-classical, tight-binding model for DNA show that there are two types of polarons, namely radial and twist polarons, which can transport charge along the DNA molecule. However, the existence of two types of base pairs in real DNA makes it crucial to find out if charge transport also exists in DNA chains with different base pairs. In this paper, we address this problem in its simple case, a homogeneous chain except for a single different base pair, which we call a base-pair inhomogeneity, and its effect on charge transport. Radial polarons experience either reflection or trapping. However, twist polarons are good candidates for charge transport along real DNA. This transport is also very robust with respect to weak parametric and diagonal disorder

Chiral pair of Fermi arcs, anomaly cancellation, and spin or valley Hall effects in Weyl metals with broken inversion symmetry

Science.gov (United States)

Jang, Iksu; Kim, Ki-Seok

2018-04-01

Anomaly cancellation has been shown to occur in broken time-reversal symmetry Weyl metals, which explains the existence of a Fermi arc. We extend this result in the case of broken inversion symmetry Weyl metals. Constructing a minimal model that takes a double pair of Weyl points, we demonstrate the anomaly cancellation explicitly. This demonstration explains why a chiral pair of Fermi arcs appear in broken inversion symmetry Weyl metals. In particular, we find that this pair of Fermi arcs gives rise to either "quantized" spin Hall or valley Hall effects, which corresponds to the "quantized" version of the charge Hall effect in broken time-reversal symmetry Weyl metals.

Pairing gaps from nuclear mean-field models

International Nuclear Information System (INIS)

Bender, M.; Rutz, K.; Maruhn, J.A.

2000-01-01

We discuss the pairing gap, a measure for nuclear pairing correlations, in chains of spherical, semi-magic nuclei in the framework of self-consistent nuclear mean-field models. The equations for the conventional BCS model and the approximate projection-before-variation Lipkin-Nogami method are formulated in terms of local density functionals for the effective interaction. We calculate the Lipkin-Nogami corrections of both the mean-field energy and the pairing energy. Various definitions of the pairing gap are discussed as three-point, four-point and five-point mass-difference formulae, averaged matrix elements of the pairing potential, and single-quasiparticle energies. Experimental values for the pairing gap are compared with calculations employing both a delta pairing force and a density-dependent delta interaction in the BCS and Lipkin-Nogami model. Odd-mass nuclei are calculated in the spherical blocking approximation which neglects part of the the core polarization in the odd nucleus. We find that the five-point mass difference formula gives a very robust description of the odd-even staggering, other approximations for the gap may differ from that up to 30% for certain nuclei. (orig.)

Effects of strain on the Schwinger pair creation in graphene

International Nuclear Information System (INIS)

Fanbanrai, P.; Hutem, A.; Boonchui, S.

2015-01-01

The effects of strain on mechanically deformed graphene are determined by looking at how the strain affects the amplitude of the Schwinger two particle pair state. The influences of the lattice distortions, such as isotropic tensile strain ϵ is , shear strain ϵ ss , uniaxial armchair strain ϵ as , and zigzag strain ϵ zs , on the photon emission spectrum have been analyzed. We find that the intensities of the emission increases or decreases when compared to those of the unstrained graphene, depending on the type of strain applied. Thus the structure of energy band, the frequencies of the photons and the emission spectrum can be controlled by use of the different strains

The role of familiarity in associative recognition of unitized compound word pairs.

Science.gov (United States)

Ahmad, Fahad N; Hockley, William E

2014-01-01

This study examined the effect of unitization and contribution of familiarity in the recognition of word pairs. Compound words were presented as word pairs and were contrasted with noncompound word pairs in an associative recognition task. In Experiments 1 and 2, yes-no recognition hit and false-alarm rates were significantly higher for compound than for noncompound word pairs, with no difference in discrimination in both within- and between-subject comparisons. Experiment 2 also showed that item recognition was reduced for words from compound compared to noncompound word pairs, providing evidence of the unitization of the compound pairs. A two-alternative forced-choice test used in Experiments 3A and 3B provided evidence that the concordant effect for compound word pairs was largely due to familiarity. A discrimination advantage for compound word pairs was also seen in these experiments. Experiment 4A showed that a different pattern of results is seen when repeated noncompound word pairs are compared to compound word pairs. Experiment 4B showed that memory for the individual items of compound word pairs was impaired relative to items in repeated and nonrepeated noncompound word pairs, and Experiment 5 demonstrated that this effect is eliminated when the elements of compound word pairs are not unitized. The concordant pattern seen in yes-no recognition and the discrimination advantage in forced-choice recognition for compound relative to noncompound word pairs is due to greater reliance on familiarity at test when pairs are unitized.

Demographic mechanisms of inbreeding adjustment through extra-pair reproduction.

Science.gov (United States)

Reid, Jane M; Duthie, A Bradley; Wolak, Matthew E; Arcese, Peter

2015-07-01

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 within

Theoretical study of GC+/GC base pair derivatives

International Nuclear Information System (INIS)

Meng Fancui; Wang Huanjie; Xu Weiren; Liu Chengbu

2005-01-01

The geometries of R (R=CH 3 , CH 3 O, F, NO 2 ) substituted GC base pair derivatives and their cations have been optimized at B3LYP/6-31G* level and the substituent effects on the neutral and cationic geometric structures and energies have been discussed. The inner reorganization energies of various base pair derivatives and the native GC base pair have been calculated to discuss the substituent effects on the reorganization energy. NBO (natural bond orbital) analysis has been carried out on both the neutral and the cationic systems to investigate the differences of the charge distributions and the electronic structures. The outcomes indicate that 8-CH 3 O-G:C has the greatest reorganization energy and 8-NO 2 -G:C has the least, while the other substituted base pairs have a reorganization energy close to that of G:C. The one charge is mostly localized on guanine part after ionization and as high as 0.95e. The bond distances of N1-N3'andN2-O2' in the cationic base pair derivatives shortened and that of O6-N4' elongated as compared with the corresponding bond distances of the neutral GC base pair derivatives

Mahonian pairs

OpenAIRE

Sagan, Bruce E.; Savage, Carla D.

2012-01-01

We introduce the notion of a Mahonian pair. Consider the set, P^*, of all words having the positive integers as alphabet. Given finite subsets S,T of P^*, we say that (S,T) is a Mahonian pair if the distribution of the major index, maj, over S is the same as the distribution of the inversion number, inv, over T. So the well-known fact that maj and inv are equidistributed over the symmetric group, S_n, can be expressed by saying that (S_n,S_n) is a Mahonian pair. We investigate various Mahonia...

Interplay of antiferromagnetism and superconductivity in cuprates with impurity effect and d-wave pairing

Energy Technology Data Exchange (ETDEWEB)

Mohapatra, Rasmita, E-mail: rmrmmohapatra@gmail.com [P.G. Department of Applied Physics and Ballistics, F.M. University, Balasore, Odisha 756019 (India); Rout, G.C., E-mail: gcr@iopb.res.in [Physics Enclave, Plot no-664/4825, Lane-4A, Shree Vihar, Patia, Bhubaneswar, Odisha 751024 (India)

2015-05-15

Highlights: • We considered here the interplay of antiferromagnetism (AFM) and Superconductivity (SC) with d-wave pairing symmetry in presence of impurity effect. • The tunneling conductance explains the multiple peaks and dip-hump structure. • It is observed that AFM coupling enhances the superconducting transition temperature. • The low temperature specific heat anomaly due to impurity atoms. - Abstract: We present here a model Hamiltonian to study the interplay between staggered magnetic field and the superconductivity with d-wave pairing symmetry in presence of hybridization between impurity f-electrons of rare-earth ions and 3d-electrons of copper ions. The staggered field and superconducting (SC) gaps are calculated by Green’s function technique and solved self-consistently. The coupling constants are compared using s-wave and d-wave pairings. The strength of hybridization suppresses the magnitude of the gaps; while antiferromagnetic coupling enhances the superconducting transition temperature, but suppresses the Neel temperature. The density of states (DOS) representing tunneling conductance shows complex character with impurity level lying at the Fermi level. The electronic specific heat explains prototype heavy fermion behavior in cuprate systems at low temperatures.

Interplay of antiferromagnetism and superconductivity in cuprates with impurity effect and d-wave pairing

International Nuclear Information System (INIS)

Mohapatra, Rasmita; Rout, G.C.

2015-01-01

Highlights: • We considered here the interplay of antiferromagnetism (AFM) and Superconductivity (SC) with d-wave pairing symmetry in presence of impurity effect. • The tunneling conductance explains the multiple peaks and dip-hump structure. • It is observed that AFM coupling enhances the superconducting transition temperature. • The low temperature specific heat anomaly due to impurity atoms. - Abstract: We present here a model Hamiltonian to study the interplay between staggered magnetic field and the superconductivity with d-wave pairing symmetry in presence of hybridization between impurity f-electrons of rare-earth ions and 3d-electrons of copper ions. The staggered field and superconducting (SC) gaps are calculated by Green’s function technique and solved self-consistently. The coupling constants are compared using s-wave and d-wave pairings. The strength of hybridization suppresses the magnitude of the gaps; while antiferromagnetic coupling enhances the superconducting transition temperature, but suppresses the Neel temperature. The density of states (DOS) representing tunneling conductance shows complex character with impurity level lying at the Fermi level. The electronic specific heat explains prototype heavy fermion behavior in cuprate systems at low temperatures

Effects of stimulus pair orientation and hand switching on reaction time estimates of interhemispheric transfer.

Science.gov (United States)

Leblanc-Sirois, Yanick; Braun, Claude M J; Elie-Fortier, Jonathan

2018-03-26

Two behavioral estimates of interhemispheric transfer time, the crossed-uncrossed difference (CUD) and the unilateral field advantage (UFA), are thought to, respectively, index transfer of premotor and visual information across the corpus callosum in neurotypical participants. However, no attempt to manipulate visual and motor contingencies in a set of tasks while measuring the CUD and the UFA has yet been reported. In two go/no-go comparison experiments, stimulus pair orientations were manipulated. The hand of response changed after each correct response in the second, but not the first experiment. No correlation was found between the CUD and the UFA, supporting the hypothesis that these two measures index different types of information transfer across hemispheres. An effect of manipulation of stimulus pair orientation on UFAs was attributed to the homotopy of callosal fibers transferring visual information, while an effect of hand switching on CUDs was attributed mostly to spatial compatibility.

An Intelligent Model for Pairs Trading Using Genetic Algorithms.

Science.gov (United States)

Huang, Chien-Feng; Hsu, Chi-Jen; Chen, Chi-Chung; Chang, Bao Rong; Li, Chen-An

2015-01-01

Pairs trading is an important and challenging research area in computational finance, in which pairs of stocks are bought and sold in pair combinations for arbitrage opportunities. Traditional methods that solve this set of problems mostly rely on statistical methods such as regression. In contrast to the statistical approaches, recent advances in computational intelligence (CI) are leading to promising opportunities for solving problems in the financial applications more effectively. In this paper, we present a novel methodology for pairs trading using genetic algorithms (GA). Our results showed that the GA-based models are able to significantly outperform the benchmark and our proposed method is capable of generating robust models to tackle the dynamic characteristics in the financial application studied. Based upon the promising results obtained, we expect this GA-based method to advance the research in computational intelligence for finance and provide an effective solution to pairs trading for investment in practice.

Sex-specific differential survival of extra-pair and within-pair offspring in song sparrows, Melospiza melodia.

Science.gov (United States)

Sardell, Rebecca J; Arcese, Peter; Keller, Lukas F; Reid, Jane M

2011-11-07

It is widely hypothesized that the evolution of female extra-pair reproduction in socially monogamous species reflects indirect genetic benefits to females. However, a critical prediction of this hypothesis, that extra-pair young (EPY) are fitter than within-pair young (WPY), has rarely been rigorously tested. We used 18 years of data from free-living song sparrows, Melospiza melodia, to test whether survival through major life-history stages differed between EPY and WPY maternal half-siblings. On average, survival of hatched chicks to independence from parental care and recruitment, and their total lifespan, did not differ significantly between EPY and WPY. However, EPY consistently tended to be less likely to survive, and recruited EPY survived for significantly fewer years than recruited WPY. Furthermore, the survival difference between EPY and WPY was sex-specific; female EPY were less likely to survive to independence and recruitment and lived fewer years than female WPY, whereas male EPY were similarly or slightly more likely to survive and to live more years than male WPY. These data indicate that extra-pair paternity may impose an indirect cost on females via their female offspring and that sex-specific genetic, environmental or maternal effects may shape extra-pair reproduction.

Anharmonic effective pair potentials of gold under high pressure and high temperature

CERN Document Server

Okube, M; Ohtaka, O; Fukui, H; Katayama, Y; Utsumi, W

2002-01-01

In order to examine the effect of pressure on the anharmonicity of Au, extended x-ray absorption fine-structure spectra near the Au L sub 3 edge were measured in the temperature range from 300 to 1100 K under pressures up to 14 GPa using large-volume high-pressure devices and synchrotron radiation. The anharmonic effective pair potentials of Au, V (u) = au sup 2 + bu sup 3 , at 0.1 MPa, 6 and 14 GPa have been calculated. The pressure dependence of the thermal expansion coefficients has also been evaluated. The reliability of the anharmonic correction proposed on the basis of the Anderson scale has been discussed.

Pair correlations in nuclei

International Nuclear Information System (INIS)

Shimizu, Yoshifumi

2009-01-01

Except for the closed shell nuclei, almost all nuclei are in the superconducting state at their ground states. This well-known pair correlation in nuclei causes various interesting phenomena. It is especially to be noted that the pair correlation becomes weak in the excited states of nuclei with high angular momentum, which leads to the pair phase transition to the normal state in the high spin limit. On the other hand, the pair correlation becomes stronger in the nuclei with lower nucleon density than in those with normal density. In the region of neutron halo or skin state of unstable nuclei, this phenomenon is expected to be further enhanced to be observed compared to the ground state of stable nuclei. An overview of those interesting aspects caused via the pair correlation is presented here in the sections titled 'pair correlations in ground states', pair correlations in high spin states' and 'pair correlations in unstable nuclei' focusing on the high spin state. (S. Funahashi)

Modeling age differences in effects of pair repetition and proactive interference using a single parameter.

Science.gov (United States)

Stephens, Joseph D W; Overman, Amy A

2018-02-01

In this article, we apply the REM model (Shiffrin & Steyvers, 1997) to age differences in associative memory. Using Criss and Shiffrin's (2005) associative version of REM, we show that in a task with pairs repeated across 2 study lists, older adults' reduced benefit of pair repetition can be produced by a general reduction in the diagnosticity of information stored in memory. This reduction can be modeled similarly well by reducing the overall distinctiveness of memory features, or by reducing the accuracy of memory encoding. We report a new experiment in which pairs are repeated across 3 study lists and extend the model accordingly. Finally, we extend the model to previously reported data using the same task paradigm, in which the use of a high-association strategy introduced proactive interference effects in young adults but not older adults. Reducing the diagnosticity of information in memory also reduces the proactive interference effect. Taken together, the modeling and empirical results reported here are consistent with the claim that some age differences that appear to be specific to associative information can be produced via general degradation of information stored in memory. The REM model provides a useful framework for examining age differences in memory as well as harmonizing seemingly conflicting prior modeling approaches for the associative deficit. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The Impact of Sustainable Development Technology on a Small Economy-The Case of Energy-Saving Technology.

Science.gov (United States)

Chen, Xiding; Huang, Qinghua; Huang, Weilun; Li, Xue

2018-02-08

We investigated the impact of a sustainable development technology on the macroeconomic variables in a small economy utilizing a case study with a stochastically improving energy saving technology and a stochastically increasing energy price. The results show the technological displacement effects of energy saving technology are stronger, but there are more ambiguous instantaneous returns to physical capital. However, the energy saving technology's displacement effects might not affect the conditions under which the Harberger-Laursen-Metzler (HLM) effect holds. The effects of rising energy prices on bonds are stronger, and there are more ambiguous instantaneous returns, but the conditions under which the HLM effect holds are different.

The Impact of Sustainable Development Technology on a Small Economy—The Case of Energy-Saving Technology

Directory of Open Access Journals (Sweden)

Xiding Chen

2018-02-01

Full Text Available We investigated the impact of a sustainable development technology on the macroeconomic variables in a small economy utilizing a case study with a stochastically improving energy saving technology and a stochastically increasing energy price. The results show the technological displacement effects of energy saving technology are stronger, but there are more ambiguous instantaneous returns to physical capital. However, the energy saving technology’s displacement effects might not affect the conditions under which the Harberger-Laursen-Metzler (HLM effect holds. The effects of rising energy prices on bonds are stronger, and there are more ambiguous instantaneous returns, but the conditions under which the HLM effect holds are different.

The Impact of Sustainable Development Technology on a Small Economy—The Case of Energy-Saving Technology

Science.gov (United States)

Huang, Qinghua; Huang, Weilun; Li, Xue

2018-01-01

We investigated the impact of a sustainable development technology on the macroeconomic variables in a small economy utilizing a case study with a stochastically improving energy saving technology and a stochastically increasing energy price. The results show the technological displacement effects of energy saving technology are stronger, but there are more ambiguous instantaneous returns to physical capital. However, the energy saving technology’s displacement effects might not affect the conditions under which the Harberger-Laursen-Metzler (HLM) effect holds. The effects of rising energy prices on bonds are stronger, and there are more ambiguous instantaneous returns, but the conditions under which the HLM effect holds are different. PMID:29419788

Effect of the temporal laser pulse asymmetry on pair production processes during intense laser-electron scattering

Science.gov (United States)

Hojbota, C. I.; Kim, Hyung Taek; Kim, Chul Min; Pathak, V. B.; Nam, Chang Hee

2018-06-01

We investigate the effects of laser pulse shape on strong-field quantum electrodynamics (QED) processes during the collision between a relativistic electron beam and an intense laser pulse. The interplay between high-energy photon emission and two pair production processes, i.e. nonlinear Breit–Wheeler (BW) and Trident, was investigated using particle-in-cell simulations. We found that the temporal evolution of these two processes could be controlled by using laser pulses with different degrees of asymmetry. The temporal envelope of the laser pulse can significantly affect the number of pairs coming from the Trident process, while the nonlinear BW process is less sensitive to it. This study shows that the two QED processes can be examined with state-of-the-art petawatt lasers and the discrimination of the two pair creation processes is feasible by adjusting the temporal asymmetry of the colliding laser pulse.

Experimental many-pairs nonlocality

Science.gov (United States)

Poh, Hou Shun; Cerè, Alessandro; Bancal, Jean-Daniel; Cai, Yu; Sangouard, Nicolas; Scarani, Valerio; Kurtsiefer, Christian

2017-08-01

Collective measurements on large quantum systems together with a majority voting strategy can lead to a violation of the Clauser-Horne-Shimony-Holt Bell inequality. In the presence of many entangled pairs, this violation decreases quickly with the number of pairs and vanishes for some critical pair number that is a function of the noise present in the system. Here we show that a different binning strategy can lead to a more substantial Bell violation when the noise is sufficiently small. Given the relation between the critical pair number and the source noise, we then present an experiment where the critical pair number is used to quantify the quality of a high visibility photon pair source. Our results demonstrate nonlocal correlations using collective measurements operating on clusters of more than 40 photon pairs.

Interaction effects on galaxy pairs with Gemini/GMOS- III: stellar population synthesis

Science.gov (United States)

Krabbe, A. C.; Rosa, D. A.; Pastoriza, M. G.; Hägele, G. F.; Cardaci, M. V.; Dors, O. L., Jr.; Winge, C.

2017-05-01

We present an observational study of the impacts of interactions on the stellar population in a sample of galaxy pairs. Long-slit spectra in the wavelength range 3440-7300 Å obtained with the Gemini Multi-Object Spectrograph (GMOS) at Gemini South for 15 galaxies in nine close pairs were used. The spatial distributions of the stellar population contributions were obtained using the stellar population synthesis code starlight. Taking into account the different contributions to the emitted light, we found that most of the galaxies in our sample are dominated by young/intermediate stellar populations. This result differs from the one derived for isolated galaxies, where the old stellar population dominates the disc surface brightness. We interpreted such different behaviour as being due to the effect of gas inflows along the discs of interacting galaxies on the star formation over a time-scale of the order of about 2 Gyr. We also found that, in general, the secondary galaxy of a pair has a higher contribution from the young stellar population than the primary one. We compared the estimated values of stellar and nebular extinction derived from the synthesis method and the Hα/Hβ emission-line ratio, finding that nebular extinctions are systematically higher than stellar ones by about a factor of 2. We did not find any correlation between nebular and stellar metallicities. Neither did we find a correlation between stellar metallicities and ages, while a positive correlation between nebular metallicities and stellar ages was obtained, with older regions being the most metal-rich.

Theory of antiferromagnetic pairing in cuprate superconductors

International Nuclear Information System (INIS)

Plakida, N.M.

2006-01-01

A review of the antiferromagnetic exchange and spin-fluctuation pairing theory in the cuprate superconductors is given. We briefly discuss a phenomenological approach and a theory in the limit of weak Coulomb correlations. A microscopic theory in the strong correlation limit is presented in more detail. In particular, results of our recently developed theory for the effective p-d Hubbard model and the reduced t-J model are given. We have proved that retardation effects for the antiferromagnetic exchange interaction are unimportant that results in pairing of all charge carriers in the conduction band and high Tc proportional to the Fermi energy. The spin-fluctuation interaction caused by kinematic interaction gives an additional contribution to the d-wave pairing. Dependence of Tc on the hole concentration and the lattice constant (or pressure) and an oxygen isotope shift are discussed

Deformed nuclear state as a quasiparticle-pair

International Nuclear Information System (INIS)

Dobaczewski, J.; Skalski, J.

1988-01-01

The deformed nuclear states, obtained in terms of the Hartree-Fock plus BCS method with the Skyrme SIII interaction, are approximated by condensates of the low-angular-momentum quasiparticle and particle pairs. The optimal pairs are determined by the variation after truncation method. The influence of the truncation on the deformation energy and the importance of the core-polarization effects are investigated

The empirical form of the effective nucleon-nucleon interaction in a model space with correlated J = O pairs

International Nuclear Information System (INIS)

Akkermans, J.N.L.; Allaart, K.

1982-01-01

Like in earlier work by Schiffer et al. the effective interaction is derived from experimental two-body multiplets. However, now the assumption is that a multiplet state is formed by two unpaired fermions relative to a core of correlated J = 0 pairs. Then the need for two ranges, as proposed Schiffer, disappears for the force between identical nucleons in a model space which is large enough to include pairing correlations. A form with a single attractive medium range is preferred for the identical nucleon interaction in order to reproduce collective 2 + states in even-even nuclei. In contrast, the proton-neutron force requires a very short range or two ranges to reproduce the empirical values of multipole coefficients, observed in odd-odd nuclei. Therefore we discuss the fact that the effective interaction is not always isospin invariant. As a typical case broken-pair calculations in the N = 50 region are considered. But the conclusions drawn, will also apply to other regions of the periodic table. (orig.)

Au pair trajectories

DEFF Research Database (Denmark)

Dalgas, Karina Märcher

2015-01-01

pair-sending families in the Philippines, this dissertation examines the long-term trajectories of these young Filipinas. It shows how the au pairs’ local and transnational family relations develop over time and greatly influence their life trajectories. A focal point of the study is how au pairs...... that Filipina au pairs see their stay abroad as an avenue of personal development and social recognition, I examine how the au pairs re-position themselves within their families at home through migration, and how they navigate between the often conflicting expectations of participation in the sociality......Since 2000, thousands of young Filipino migrants have come to Denmark as au pairs. Officially, they are there to “broaden their cultural horizons” by living temporarily with a Danish host family, but they also conduct domestic labor in exchange for food and money, which allows them to send...

Instantons in lepton pair production

International Nuclear Information System (INIS)

Brandenburg, A.; Ringwald, A.; Utermann, A.

2006-05-01

We consider QCD instanton-induced contributions to lepton pair production in hadron-hadron collisions. We relate these contributions to those known from deep inelastic scattering and demonstrate that they can be calculated reliably for sufficiently large momentum transfer. We observe that the instanton contribution to the angular distribution of the lepton pairs at finite momentum transfer strongly violates the Lam-Tung relation - a relation between coefficient functions of the angular distribution which is valid within the framework of ordinary perturbation theory. The drastic violation of this relation, as seen in experimental data, might be related to such instanton-induced effects. (Orig.)

Dislocation processes in quasicrystals-Kink-pair formation control or jog-pair formation control

International Nuclear Information System (INIS)

Takeuchi, Shin

2005-01-01

A computer simulation of dislocation in a model quasiperiodic lattice indicates that the dislocation feels a large Peierls potential when oriented in particular directions. For a dislocation with a high Peierls potential, the glide velocity and the climb velocity of the dislocation can be described almost in parallel in terms of the kink-pair formation followed by kink motion and the jog-pair formation followed by jog motion, respectively. The activation enthalpy of the kink-pair formation is the sum of the kink-pair formation enthalpy and the atomic jump activation enthalpy, while the activation enthalpy of the jog-pair formation involves the jog-pair enthalpy and the self-diffusion enthalpy. Since the kink-pair energy can be considerably larger than the jog-pair energy, the climb velocity can be faster than the glide velocity, so that the plastic deformation of quasicrystals can be brought not by dislocation glide but by dislocation climb at high temperatures

Shape of Cooper pairs in a norma.-metal/superconductors junction

NARCIS (Netherlands)

Tanaka, Yukio; Asano, Yasuhiro; Golubov, Alexandre Avraamovitch

2008-01-01

In s-wave superconductors the Cooper pair wave function is isotropic in momentum space. This property may also be expected for Cooper pairs entering a normal metal from a superconductor due to the proximity effect. We show, however, that such a deduction is incorrect and the pairing function in a

QCD angular correlations for muon pair production

International Nuclear Information System (INIS)

Kajantie, K.; Raitio, R.; Lindfors, J.

1978-01-01

Angular distributions of muons are discussed in the framework of a QCD treatment of muon pair production in hadron-hadron collisions. The predicted angular effects are independent of the infrared behavior of QCD. Measuring them will permit one to determine whether the origin of the large transverse momentum of the pair is in the quark transverse momenta or in a constituent-constituent subprocess. (author)

Pair correlation of super-deformed rotation band

International Nuclear Information System (INIS)

Shimizu, Yoshio

1989-01-01

The effect of pair correlation, one of the most important residual interactions associated with the super-deformed rotation band, is discussed in terms of the characteristics of the rotation band (its effect on the moment of inertia in particular), and the tunneling into an normal deformed state in relation to its effect on the angular momentum dependence of the potential energy plane as a function of the deformation. The characteristics of the rotation band is discussed in terms of the kinematic and dynamic momenta of inertia. It is shown that the pair correlation in a super-deformed rotation band acts to decrease the former and increase the latter momentum mainly due to dynamic pair correlation. A theoretical approach that takes this effect into account can provide results that are consistent with measured momenta, although large differences can occur in some cases. Major conflicts include a large measured kinetic momentum of inertia compared to the theoretical value, and the absence of the abnormality (shape increase) generally seen in low-spin experiments. The former seems likely to be associated with the method of measuring the angular momentum. (N.K.)

Hot accretion disks with electron-positron pairs

International Nuclear Information System (INIS)

White, T.R.; Lightman, A.P.

1989-01-01

The hot thermal accretion disks of the 1970s are studied and consideration is given to the effects of electron-positron pairs, which were originally neglected. It is found that disks cooled by internally produced photons have a critical accretion rate above which equilibrium is not possible in a radial annulus centered around r = 10 GM/c-squared, where M is the mass of the central object. This confirms and extends previous work by Kusunose and Takahara. Above the critical rate, pairs are created more rapidly than they can be destroyed. Below the critical rate, there are two solutions to the disk structure, one with a high pair density and one with a low pair density. Depending on the strength of the viscosity, the critical accretion rate corresponds to a critical luminosity of about 3-10 percent of the Eddington limit. 32 refs

AudioPairBank: Towards A Large-Scale Tag-Pair-Based Audio Content Analysis

OpenAIRE

Sager, Sebastian; Elizalde, Benjamin; Borth, Damian; Schulze, Christian; Raj, Bhiksha; Lane, Ian

2016-01-01

Recently, sound recognition has been used to identify sounds, such as car and river. However, sounds have nuances that may be better described by adjective-noun pairs such as slow car, and verb-noun pairs such as flying insects, which are under explored. Therefore, in this work we investigate the relation between audio content and both adjective-noun pairs and verb-noun pairs. Due to the lack of datasets with these kinds of annotations, we collected and processed the AudioPairBank corpus cons...

The paired-domination and the upper paired-domination numbers of graphs

Directory of Open Access Journals (Sweden)

Włodzimierz Ulatowski

2015-01-01

Full Text Available In this paper we continue the study of paired-domination in graphs. A paired-dominating set, abbreviated PDS, of a graph \\(G\\ with no isolated vertex is a dominating set of vertices whose induced subgraph has a perfect matching. The paired-domination number of \\(G\\, denoted by \\(\\gamma_{p}(G\\, is the minimum cardinality of a PDS of \\(G\\. The upper paired-domination number of \\(G\\, denoted by \\(\\Gamma_{p}(G\\, is the maximum cardinality of a minimal PDS of \\(G\\. Let \\(G\\ be a connected graph of order \\(n\\geq 3\\. Haynes and Slater in [Paired-domination in graphs, Networks 32 (1998, 199-206], showed that \\(\\gamma_{p}(G\\leq n-1\\ and they determine the extremal graphs \\(G\\ achieving this bound. In this paper we obtain analogous results for \\(\\Gamma_{p}(G\\. Dorbec, Henning and McCoy in [Upper total domination versus upper paired-domination, Questiones Mathematicae 30 (2007, 1-12] determine \\(\\Gamma_{p}(P_n\\, instead in this paper we determine \\(\\Gamma_{p}(C_n\\. Moreover, we describe some families of graphs \\(G\\ for which the equality \\(\\gamma_{p}(G=\\Gamma_{p}(G\\ holds.

[Comparative study on promoting blood effects of Danshen-Honghua herb pair with different preparations based on chemometrics and multi-attribute comprehensive index methods].

Science.gov (United States)

Qu, Cheng; Tang, Yu-Ping; Shi, Xu-Qin; Zhou, Gui-Sheng; Shang, Er-Xin; Shang, Li-Li; Guo, Jian-Ming; Liu, Pei; Zhao, Jing; Zhao, Bu-Chang; Duan, Jin-Ao

2017-08-01

To evaluate the promoting blood circulation and removing blood stasis effects of Danshen-Honghua(DH) herb pair with different preparations (alcohol, 50% alcohol and water) on blood rheology and coagulation functions in acute blood stasis rats, and optimize the best preparation method of DH based on principal component analysis(PCA), hierarchical cluster heatmap analysis and multi-attribute comprehensive index methods. Ice water bath and subcutaneous injection of adrenaline were both used to establish the acute blood stasis rat model. Then the blood stasis rats were administrated intragastrically with DH (alcohol, 50% alcohol and water) extracts. The whole blood viscosity(WBV), plasma viscosity(PV), erythrocyte sedimentation rate(ESR) and haematocrit(HCT) were tested to observe the effects of DH herb pair with different preparations and doses on hemorheology of blood stasis rats; the activated partial thromboplastin time(APTT), thrombin time(TT), prothrombin time(PT), and plasma fibrinogen(FIB) were tested to observe the effects of DH herb pair with different preparations on blood coagulation function and platelet aggregation of blood stasis rats. Then PCA, hierarchical cluster heatmap analysis and multi-attribute comprehensive index methods were all used to comprehensively evaluate the total promoting blood circulation and removing blood stasis effects of DH herb pair with different preparations. The hemorheological indexes and coagulation parameters of model group had significant differences with normal blank group. As compared with the model group, the DH herb pair with different preparations at low, middle and high doses could improve the blood hemorheology indexes and coagulation parameters in acute blood stasis rats with dose-effect relation. Based on the PCA, hierarchical cluster heatmap analysis and multi-attribute comprehensive index methods, the high dose group of 50% alcohol extract had the best effect of promoting blood circulation and removing blood

Odd-frequency pairing in superconducting heterostructures

Energy Technology Data Exchange (ETDEWEB)

Golubov, A A [Faculty of Science and Technology and MESA Institute for Nanotechnology, University of Twente, 7500 AE Enschede (Netherlands); Tanaka, Y [Department of Applied Physics, Nagoya University, Nagoya, 464-8603 (Japan); Asano, Y [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Tanuma, Y [Institute of Physics, Kanagawa University, 3-7-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan)], E-mail: a.golubov@utwente.nl

2009-04-22

We review the theory of odd-frequency pairing in superconducting heterostructures, where an odd-frequency pairing component is induced near interfaces. A general description of the superconducting proximity effect in a normal metal or a ferromagnet attached to an unconventional superconductor (S) is given within quasiclassical kinetic theory for various types of symmetry state in S. Various possible symmetry classes in a superconductor are considered which are consistent with the Pauli principle: even-frequency spin-singlet even-parity (ESE) state, even-frequency spin-triplet odd-parity (ETO) state, odd-frequency spin-triplet even-parity (OTE) state and odd-frequency spin-singlet odd-parity (OSO) state. As an example, we consider a junction between a diffusive normal metal (DN) and a p-wave superconductor (even-frequency spin-triplet odd-parity symmetry), where the pairing amplitude in DN belongs to an odd-frequency spin-triplet even-parity symmetry class. We also discuss the manifestation of odd-frequency pairing in conventional superconductor/normal (S/N) proximity systems and its relation to the classical McMillan-Rowell oscillations.

Effect of screening current induced pair breaking on magnetization of superconducting lead nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Yashwant, G.; Prajapat, C.L. [Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India); Jayakumar, O.D. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India); Singh, M.R.; Gupta, S.K. [Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India); Tyagi, A.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India); Ravikumar, G. [Technical Physics and Prototype Engineering Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra 400 085 (India)], E-mail: gurazada@barc.gov.in

2008-06-15

Magnetization measurements on lead nanoparticles in the size range 35-45 nm are presented. It is shown that the critical fields in these nanoparticles are enhanced significantly above their bulk values with temperature dependence also distinct from that of bulk. The observed 'type II' like shape of the magnetization curves is explained on the basis of the Ginzburg-Landau phenomenology by invoking the pair breaking effect of the London screening currents, which makes the effective penetration depth an increasing function of the field. The temperature dependence of critical field is found to be consistent with our explanation.

Base pair probability estimates improve the prediction accuracy of RNA non-canonical base pairs.

Directory of Open Access Journals (Sweden)

Michael F Sloma

2017-11-01

Full Text Available Prediction of RNA tertiary structure from sequence is an important problem, but generating accurate structure models for even short sequences remains difficult. Predictions of RNA tertiary structure tend to be least accurate in loop regions, where non-canonical pairs are important for determining the details of structure. Non-canonical pairs can be predicted using a knowledge-based model of structure that scores nucleotide cyclic motifs, or NCMs. In this work, a partition function algorithm is introduced that allows the estimation of base pairing probabilities for both canonical and non-canonical interactions. Pairs that are predicted to be probable are more likely to be found in the true structure than pairs of lower probability. Pair probability estimates can be further improved by predicting the structure conserved across multiple homologous sequences using the TurboFold algorithm. These pairing probabilities, used in concert with prior knowledge of the canonical secondary structure, allow accurate inference of non-canonical pairs, an important step towards accurate prediction of the full tertiary structure. Software to predict non-canonical base pairs and pairing probabilities is now provided as part of the RNAstructure software package.

Base pair probability estimates improve the prediction accuracy of RNA non-canonical base pairs.

Science.gov (United States)

Sloma, Michael F; Mathews, David H

2017-11-01

Prediction of RNA tertiary structure from sequence is an important problem, but generating accurate structure models for even short sequences remains difficult. Predictions of RNA tertiary structure tend to be least accurate in loop regions, where non-canonical pairs are important for determining the details of structure. Non-canonical pairs can be predicted using a knowledge-based model of structure that scores nucleotide cyclic motifs, or NCMs. In this work, a partition function algorithm is introduced that allows the estimation of base pairing probabilities for both canonical and non-canonical interactions. Pairs that are predicted to be probable are more likely to be found in the true structure than pairs of lower probability. Pair probability estimates can be further improved by predicting the structure conserved across multiple homologous sequences using the TurboFold algorithm. These pairing probabilities, used in concert with prior knowledge of the canonical secondary structure, allow accurate inference of non-canonical pairs, an important step towards accurate prediction of the full tertiary structure. Software to predict non-canonical base pairs and pairing probabilities is now provided as part of the RNAstructure software package.

Electrostatics Explains the Position-Dependent Effect of G⋅U Wobble Base Pairs on the Affinity of RNA Kissing Complexes.

Science.gov (United States)

Abi-Ghanem, Josephine; Rabin, Clémence; Porrini, Massimiliano; Dausse, Eric; Toulmé, Jean-Jacques; Gabelica, Valérie

2017-10-06

In the RNA realm, non-Watson-Crick base pairs are abundant and can affect both the RNA 3D structure and its function. Here, we investigated the formation of RNA kissing complexes in which the loop-loop interaction is modulated by non-Watson-Crick pairs. Mass spectrometry, surface plasmon resonance, and UV-melting experiments show that the G⋅U wobble base pair favors kissing complex formation only when placed at specific positions. We tried to rationalize this effect by molecular modeling, including molecular mechanics Poisson-Boltzmann surface area (MMPBSA) thermodynamics calculations and PBSA calculations of the electrostatic potential surfaces. Modeling reveals that the G⋅U stabilization is due to a specific electrostatic environment defined by the base pairs of the entire loop-loop region. The loop is not symmetric, and therefore the identity and position of each base pair matters. Predicting and visualizing the electrostatic environment created by a given sequence can help to design specific kissing complexes with high affinity, for potential therapeutic, nanotechnology or analytical applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Importance of interlayer pair tunneling: A variational perspective

International Nuclear Information System (INIS)

Medhi, Amal; Basu, Saurabh

2011-01-01

We study the effect of interlayer pair tunneling in a bilayer superconductor where each layer is described by a two dimensional t-J model and the two layers are connected by the Josephson pair tunneling term. We study this model using a grand canonical variational Monte Carlo (GVMC) method, for which we develop a new algorithm to perform Monte Carlo simulation of a system with fluctuating particle number. The variational wavefunction is taken to be the product of two Gutzwiller projected d-wave BCS wavefunctions with variable particle densities, one for each layer. We calculate the energy of the above state as a function of the d-wave superconducting gap parameter, Δ. We find that the interlayer pair tunneling energy, E perpendicular shows interesting variation with Δ. E perpendicular tends to enhance the optimal value of Δ, thereby the superconducting pairing. However the magnitude of the tunneling energy is found to be too small to have any appreciable effect on the physical properties. While the result is supported by early experiments and hence may appear known to the community, the current work presents a new approach to the problem and confirms the diminished role of interlayer pair tunneling by directly calculating its contribution to superconducting condensation energy.

Electron-positron pair production in Coulomb collisions at ultrarelativistic energies

International Nuclear Information System (INIS)

Vane, C.R.; Datz, S.; Dittner, P.F.; Krause, H.F.; Bottcher, C.; Strayer, M.; Schuch, R.; Gao, H.; Hutton, R.

1993-01-01

We have measured angular and momentum distributions for electrons and positrons created as pairs in peripheral collisions of 6.4 TeV bare sulfur ions with fixed targets of Al, Pd, and Au. Singly- and doubly-differential cross sections have been determined for 1--17 MeV/c electrons and positrons detected independently and in coincidence as pairs. Integrated yields for pair production are found to vary as the square of the target nuclear charge. Relative angular and momentum differential cross sections are effectively target independent. Probability distributions for the pair total momentum, the positron fraction of the pair momentum, and the pair traverse momentum have been derived from the coincident electron-positron data

Pairing from strong repulsion in triangular lattice Hubbard model

Science.gov (United States)

Zhang, Shang-Shun; Zhu, Wei; Batista, Cristian D.

2018-04-01

We propose a pairing mechanism between holes in the dilute limit of doped frustrated Mott insulators. Hole pairing arises from a hole-hole-magnon three-body bound state. This pairing mechanism has its roots on single-hole kinetic energy frustration, which favors antiferromagnetic (AFM) correlations around the hole. We demonstrate that the AFM polaron (hole-magnon bound state) produced by a single hole propagating on a field-induced polarized background is strong enough to bind a second hole. The effective interaction between these three-body bound states is repulsive, implying that this pairing mechanism is relevant for superconductivity.

Polarization effects for pair creation by photon in oriented crystals at high energy

International Nuclear Information System (INIS)

Baier, V.N.; Katkov, V.M.

2006-01-01

Pair creation by a photon in an oriented crystal is considered in the frame of the quasiclassical operator method, which includes processes with polarized particles. Under some quite generic assumptions the general expression is derived for the probability of pair creation of longitudinally polarized electron (positron) by circularly polarized photon in oriented crystal. In the particular cases θ > V /m (θ is the angle of incidence, angle between the momentum of the initial photon and axis (plane) of crystal, V is the scale of a potential of axis or a plane relative to which the angle θ is defined) one has the constant field approximation and the coherent pair production theory correspondingly. Side by side with coherent process the probability of incoherent pair creation is calculated, which differs essentially from amorphous one. At high energy the pair creation in oriented crystal is strongly enhanced comparing with the amorphous medium. In the corresponding appendixes the integral polarization of positron is found in an external field and for the coherent and incoherent mechanisms

Pairing of heterochromatin in response to cellular stress

International Nuclear Information System (INIS)

Abdel-Halim, H.I.; Mullenders, L.H.F.; Boei, J.J.W.A.

2006-01-01

We previously reported that exposure of human cells to DNA-damaging agents (X-rays and mitomycin C (MMC)) induces pairing of the homologous paracentromeric heterochromatin of chromosome 9 (9q12-13). Here, we show that UV irradiation and also heat shock treatment of human cells lead to similar effects. Since the various agents induce very different types and frequencies of damage to cellular constituents, the data suggest a general stress response as the underlying mechanism. Moreover, local UV irradiation experiments revealed that pairing of heterochromatin is an event that can be triggered without induction of DNA damage in the heterochromatic sequences. The repair deficient xeroderma pigmentosum cells (group F) previously shown to fail pairing after MMC displayed elevated pairing after heat shock treatment but not after UV exposure. Taken together, the present results indicate that pairing of heterochromatin following exposure to DNA-damaging agents is initiated by a general stress response and that the sensing of stress or the maintenance of the paired status of the heterochromatin might be dependent on DNA repair

Pairing fluctuation effects on the single-particle spectra for the superconducting state

International Nuclear Information System (INIS)

Pieri, P.; Pisani, L.; Strinati, G.C.

2004-01-01

Single-particle spectra are calculated in the superconducting state for a fermionic system with an attractive interaction, as functions of temperature and coupling strength from weak to strong. The fermionic system is described by a single-particle self-energy that includes pairing-fluctuation effects in the superconducting state. The theory reduces to the ordinary BCS approximation in weak coupling and to the Bogoliubov approximation for the composite bosons in strong coupling. Several features of the single-particle spectral function are shown to compare favorably with experimental data for cuprate superconductors

Pair- ${v}$ -SVR: A Novel and Efficient Pairing nu-Support Vector Regression Algorithm.

Science.gov (United States)

Hao, Pei-Yi

This paper proposes a novel and efficient pairing nu-support vector regression (pair--SVR) algorithm that combines successfully the superior advantages of twin support vector regression (TSVR) and classical -SVR algorithms. In spirit of TSVR, the proposed pair--SVR solves two quadratic programming problems (QPPs) of smaller size rather than a single larger QPP, and thus has faster learning speed than classical -SVR. The significant advantage of our pair--SVR over TSVR is the improvement in the prediction speed and generalization ability by introducing the concepts of the insensitive zone and the regularization term that embodies the essence of statistical learning theory. Moreover, pair--SVR has additional advantage of using parameter for controlling the bounds on fractions of SVs and errors. Furthermore, the upper bound and lower bound functions of the regression model estimated by pair--SVR capture well the characteristics of data distributions, thus facilitating automatic estimation of the conditional mean and predictive variance simultaneously. This may be useful in many cases, especially when the noise is heteroscedastic and depends strongly on the input values. The experimental results validate the superiority of our pair--SVR in both training/prediction speed and generalization ability.This paper proposes a novel and efficient pairing nu-support vector regression (pair--SVR) algorithm that combines successfully the superior advantages of twin support vector regression (TSVR) and classical -SVR algorithms. In spirit of TSVR, the proposed pair--SVR solves two quadratic programming problems (QPPs) of smaller size rather than a single larger QPP, and thus has faster learning speed than classical -SVR. The significant advantage of our pair--SVR over TSVR is the improvement in the prediction speed and generalization ability by introducing the concepts of the insensitive zone and the regularization term that embodies the essence of statistical learning theory

Isovector pairing effect on the particle-number projection two-proton separation energy

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, Djamila; Kerrouchi, Slimane [Laboratoire de Physique Theorique, Faculte de Physique, Algiers (Algeria); Fellah, Mohamed; Allal, Nassima-Hosni [Laboratoire de Physique Theorique, Faculte de Physique, Algiers (Algeria); Centre de Recherche Nucleaire d' Alger, Comena, Algiers (Algeria)

2009-07-01

The two-proton separation energy is studied by performing a particle-number projection with and without inclusion of the isovector neutron-proton (np) pairing correlations. It is numerically evaluated for even-even rare-earth nuclei such that the np pairing parameter is non-zero. It is shown that the two-proton separation energy values calculated using the two approaches join, for almost all the considered elements, for the highest values of (N-Z). However, the results including the np pairing correlations are closest to the experimental data when available. Moreover, the two methods lead to the same prediction of the two-proton drip-line position, except for the Dysprosium and the Tungsten.

Finite-thickness effect on speed of a counter-rotating vortex pair at high Reynolds numbers

Science.gov (United States)

Habibah, Ummu; Nakagawa, Hironori; Fukumoto, Yasuhide

2018-03-01

We establish a general formula for the translational speed of a counter-rotating vortex pair, valid for thick cores, moving in an incompressible fluid with and without viscosity. We extend to higher order the method of matched asymptotic expansions developed by Ting and Tung (1965 Phys. Fluids 8 1039–51). The solution of the Euler or the Navier–Stokes equations is constructed in the form of a power series in a small parameter, the ratio of the core radius to the distance between the core centers. For a viscous vortex pair, the small parameter should be \\sqrt{ν /{{Γ }}} where ν is the kinematic viscosity of the fluid and Γ is the circulation of each vortex. A correction due to the effect of finite thickness of the vortices to the traveling speed makes its appearance at fifth order. A drastic simplification is achieved of expressing it solely in terms of the strength of the second-order quadrupole field associated with the elliptical deformation of the core. For a viscous vortex pair, we exploit the conservation law for the hydrodynamic impulse to derive the growth of the distance between the vortices, which is cubic in time.

Report on Pairing-based Cryptography.

Science.gov (United States)

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.

Effects of interlayer Sn-Sn lone pair interaction on the band gap of bulk and nanosheet SnO

Science.gov (United States)

Umezawa, Naoto; Zhou, Wei

2015-03-01

Effects of interlayer lone-pair interactions on the electronic structure of SnO are firstly explored by the density-functional theory. Our comprehensive study reveals that the band gap of SnO opens as increase in the interlayer Sn-Sn distance. The effect is rationalized by the character of band edges which consists of bonding and anti-bonding states from interlayer lone pair interactions. The band edges for several nanosheets and strained double-layer SnO are estimated. We conclude that the double-layer SnO is a promising material for visible-light driven photocatalyst for hydrogen evolution. This work is supported by the Japan Science and Technology Agency (JST) Precursory Research for Embryonic Science and Technology (PRESTO) program.

Strong enhancement of Penning ionization for asymmetric atom pairs in cold Rydberg gases: the Tom and Jerry effect

KAUST Repository

Efimov, D K

2016-05-18

We consider Penning ionization of Rydberg atom pairs as an Auger-type process induced by the dipole-dipole interaction and employ semiclassical formulae for dipole transitions to calculate the autoionization width as a function of the principal quantum numbers, n d, n i, of both atoms. While for symmetric atom pairs with the well-known increase of the autoionization width with increasing n 0 is obtained, the result for asymmetric pairs is counterintuitive - for a fixed n i of the ionizing atom of the pair, the autoionization width strongly increases with decreasing n d of the de-excited atom. For H Rydberg atoms this increase reaches two orders of magnitude at the maximum of the n d dependence, and the same type of counterintuitive behavior is exhibited also by Na, Rb and Cs atoms. This is a purely quantum-mechanical effect, which points towards existence of optimal (we call them \\'Tom\\' and \\'Jerry\\' for \\'big\\' and \\'small\\') pairs of Rydberg atoms with respect to autoionization efficiency. Building on the model of population redistribution in cold Rydberg gases proposed in [1], we demonstrate that population evolution following the initial laser excitation of Rydberg atoms in state n 0 would eventually lead to the formation of such Tom-Jerry pairs with which feature autoionization widths that are enhanced by several orders of magnitude compared to that of two atoms in the initial laser-excited state n 0. We also show that in the high-density regime of cold Rydberg gas experiments the ionization rate of Tom-Jerry pairs can be substantially larger than the blackbody radiation-induced photoionization rate. © 2016 IOP Publishing Ltd.

Shell and pairing effects in spherical nuclei close to the nucleon drip lines

International Nuclear Information System (INIS)

Beiner, M.; Lombard, R.J.

1975-01-01

The unstability against nucleon emission of light and medium exotic spherical nuclei is investigated systematically using an extended version of the energy density formalism which reproduces correctly shell and pairing effects in stable nuclei. The reliability of the predictions of this microscopic, self-consistent and weakly parametrized model should not decrease significantly with the distance of the nuclei from the β-stability line, what is not the case for conventional mass formulae or mass tables [fr

Effects of pair correlation functions on intermolecular nuclear relaxation by translational and rotational diffusion in liquids

International Nuclear Information System (INIS)

Fries, P.

1978-01-01

In order to study the intermolecular relaxation due to magnetic dipolar interactions, we calculate the spectral densities resulting from random translational and rotational motions of spherical molecules carrying off-centre spins. The relative translational motion is treated in the frame-work of a general diffusion equation (the Smoluchowski equation) which takes into account the existence of effective forces between the molecules. This model implies a pair correlation function. i.e. a non unifom relative distribution of the molecules. The analytical calculations are carried out by taking correctly into account the hard sphere boundary conditions for the molecules. Explicit numerical calculations of the spectral densities are performed using finite difference methods and the pair correlation function of Verlet and Weiss obtained by computer experiments. The resulting calculations allow one to interpret the relaxation exhibited by benzene and some of its monohalogen derivatives which has been measured by Jonas et al. at various pressures. The effects of pair correlation and eccentricity contribute to a noticeable enhancement of the spectral densities, especially as the frequency increases. The translational correlation times calculated from the Stokes formula and those deduced from intermolecular relaxation studies are compared. It is shown that in order to distinguish which of the dynamical models is appropriate, measurements must be made as a function of frequency [fr

Visual paired-associate learning: in search of material-specific effects in adult patients who have undergone temporal lobectomy.

Science.gov (United States)

Smith, Mary Lou; Bigel, Marla; Miller, Laurie A

2011-02-01

The mesial temporal lobes are important for learning arbitrary associations. It has previously been demonstrated that left mesial temporal structures are involved in learning word pairs, but it is not yet known whether comparable lesions in the right temporal lobe impair visually mediated associative learning. Patients who had undergone left (n=16) or right (n=18) temporal lobectomy for relief of intractable epilepsy and healthy controls (n=13) were administered two paired-associate learning tasks assessing their learning and memory of pairs of abstract designs or pairs of symbols in unique locations. Both patient groups had deficits in learning the designs, but only the right temporal group was impaired in recognition. For the symbol location task, differences were not found in learning, but again a recognition deficit was found for the right temporal group. The findings implicate the mesial temporal structures in relational learning. They support a material-specific effect for recognition but not for learning and recall of arbitrary visual and visual-spatial associative information. Copyright © 2010 Elsevier Inc. All rights reserved.

Effects of Guided Discovery and Think-Pair-Share Strategies on Secondary School Students’ Achievement in Chemistry

Directory of Open Access Journals (Sweden)

Adekunle Oladipupo Bamiro

2015-01-01

Full Text Available This study investigated the effects of three strategies (i.e., guided discovery, think-pair-share, and lecture on senior secondary school students’ achievement in chemistry. A pretest, posttest, control group quasi-experimental design with a 3 × 3 × 2 factorial matrix was adopted for the study. Treatment was at three levels (guided discovery, think-pair-share, and lecture strategies. Intervening variables were cognitive entry behavior at three levels (high, middle, and low and gender at two levels (male and female. Two hundred forty-two Senior Secondary 1 students in intact classes from six secondary schools in Ijebu Ode and Odogbolu Local Government Areas of Ogun State were randomly assigned to the treatment and control groups. Three instruments were developed and used to collect data from students during the 8-week treatment program. The data collected were subjected to analysis of covariance and multiple classification analysis. Scheffé test was further used as post hoc measures. Where significant interactions were observed, they were represented with graphical illustrations. It was found that students taught with guided discovery and think-pair-share strategies obtained significantly higher posttest mean scores than those in the lecture strategy, F(4, 223 = 51.66, p < .05. The use of guided discovery and think-pair-share strategies had great potential for improving achievement in chemistry and science learning generally.

Impact of CYP2C8*3 polymorphism on in vitro metabolism of imatinib to N-desmethyl imatinib.

Science.gov (United States)

Khan, Muhammad Suleman; Barratt, Daniel T; Somogyi, Andrew A

2016-01-01

1. Imatinib is metabolized to N-desmethyl imatinib by CYPs 3A4 and 2C8. The effect of CYP2C8*3 genotype on N-desmethyl imatinib formation was unknown. 2. We examined imatinib N-demethylation in human liver microsomes (HLMs) genotyped for CYP2C8*3, in CYP2C8*3/*3 pooled HLMs and in recombinant CYP2C8 and CYP3A4 enzymes. Effects of CYP-selective inhibitors on N-demethylation were also determined. 3. A single-enzyme Michaelis-Menten model with autoinhibition best fitted CYP2C8*1/*1 HLM (n = 5) and recombinant CYP2C8 kinetic data (median ± SD Ki = 139 ± 61 µM and 149 µM, respectively). Recombinant CYP3A4 showed two-site enzyme kinetics with no autoinhibition. Three of four CYP2C8*1/*3 HLMs showed single-enzyme kinetics with no autoinhibition. Binding affinity was higher in CYP2C8*1/*3 than CYP2C8*1/*1 HLM (median ± SD Km = 6 ± 2 versus 11 ± 2 µM, P=0.04). CYP2C8*3/*3 (pooled HLM) also showed high binding affinity (Km = 4 µM) and single-enzyme weak autoinhibition (Ki = 449 µM) kinetics. CYP2C8 inhibitors reduced HLM N-demethylation by 47-75%, compared to 0-30% for CYP3A4 inhibitors. 4. In conclusion, CYP2C8*3 is a gain-of-function polymorphism for imatinib N-demethylation, which appears to be mainly mediated by CYP2C8 and not CYP3A4 in vitro in HLM.

Metal-mediated DNA base pairing: alternatives to hydrogen-bonded Watson-Crick base pairs.

Science.gov (United States)

Takezawa, Yusuke; Shionoya, Mitsuhiko

2012-12-18

With its capacity to store and transfer the genetic information within a sequence of monomers, DNA forms its central role in chemical evolution through replication and amplification. This elegant behavior is largely based on highly specific molecular recognition between nucleobases through the specific hydrogen bonds in the Watson-Crick base pairing system. While the native base pairs have been amazingly sophisticated through the long history of evolution, synthetic chemists have devoted considerable efforts to create alternative base pairing systems in recent decades. Most of these new systems were designed based on the shape complementarity of the pairs or the rearrangement of hydrogen-bonding patterns. We wondered whether metal coordination could serve as an alternative driving force for DNA base pairing and why hydrogen bonding was selected on Earth in the course of molecular evolution. Therefore, we envisioned an alternative design strategy: we replaced hydrogen bonding with another important scheme in biological systems, metal-coordination bonding. In this Account, we provide an overview of the chemistry of metal-mediated base pairing including basic concepts, molecular design, characteristic structures and properties, and possible applications of DNA-based molecular systems. We describe several examples of artificial metal-mediated base pairs, such as Cu(2+)-mediated hydroxypyridone base pair, H-Cu(2+)-H (where H denotes a hydroxypyridone-bearing nucleoside), developed by us and other researchers. To design the metallo-base pairs we carefully chose appropriate combinations of ligand-bearing nucleosides and metal ions. As expected from their stronger bonding through metal coordination, DNA duplexes possessing metallo-base pairs exhibited higher thermal stability than natural hydrogen-bonded DNAs. Furthermore, we could also use metal-mediated base pairs to construct or induce other high-order structures. These features could lead to metal-responsive functional

Spin-Triplet Pairing Induced by Spin-Singlet Interactions in Noncentrosymmetric Superconductors

Science.gov (United States)

Matsuzaki, Tomoaki; Shimahara, Hiroshi

2017-02-01

In noncentrosymmetric superconductors, we examine the effect of the difference between the intraband and interband interactions, which becomes more important when the band splitting increases. We define the difference ΔVμ between their coupling constants, i.e., that between the intraband and interband hopping energies of intraband Cooper pairs. Here, the subscript μ of ΔVμ indicates that the interactions scatter the spin-singlet and spin-triplet pairs when μ = 0 and μ = 1,2,3, respectively. It is shown that the strong antisymmetric spin-orbit interaction reverses the target spin parity of the interaction: it converts the spin-singlet and spin-triplet interactions represented by ΔV0 and ΔVμ>0 into effective spin-triplet and spin-singlet pairing interactions, respectively. Hence, for example, triplet pairing can be induced solely by the singlet interaction ΔV0. We name the pairing symmetry of the system after that of the intraband Cooper pair wave function, but with an odd-parity phase factor excluded. The pairing symmetry must then be even, even for the triplet component, and the following results are obtained. When ΔVμ is small, the spin-triplet p-wave interactions induce spin-triplet s-wave and spin-triplet d-wave pairings in the regions where the repulsive singlet s-wave interaction is weak and strong, respectively. When ΔV0 is large, a repulsive interband spin-singlet interaction can stabilize spin-triplet pairing. When the Rashba interaction is adopted for the spin-orbit interaction, the spin-triplet pairing interactions mediated by transverse magnetic fluctuations do not contribute to triplet pairing.

Inflation of the screening length induced by Bjerrum pairs

NARCIS (Netherlands)

Zwanikken, J.W.; van Roij, R.H.H.G.

2009-01-01

Within a modified Poisson–Boltzmann theory we study the effect of Bjerrum pairs on the typical length scale 1/¯κ over which electric fields are screened in electrolyte solutions, taking into account a simple association–dissociation equilibrium between free ions and Bjerrum pairs. At low densities

Space-Efficient Re-Pair Compression

DEFF Research Database (Denmark)

Bille, Philip; Gørtz, Inge Li; Prezza, Nicola

2017-01-01

Re-Pair [5] is an effective grammar-based compression scheme achieving strong compression rates in practice. Let n, σ, and d be the text length, alphabet size, and dictionary size of the final grammar, respectively. In their original paper, the authors show how to compute the Re-Pair grammar...... in expected linear time and 5n + 4σ2 + 4d + √n words of working space on top of the text. In this work, we propose two algorithms improving on the space of their original solution. Our model assumes a memory word of [log2 n] bits and a re-writable input text composed by n such words. Our first algorithm runs...

Female bluethroats enhance offspring immunocompetence through extra-pair copulations.

Science.gov (United States)

Johnsen, A; Andersen, V; Sunding, C; Lifjeld, J T

2000-07-20

Female birds frequently copulate with extra-pair males, but the adaptive value of this behaviour is poorly understood. Some studies have suggested that 'good genes' may be involved, where females seek to have their eggs fertilized by high-quality males without receiving any material benefits from them. Nevertheless, it remains to be shown that a genetic benefit is passed on to offspring. Here we report that nestling bluethroats, Luscinia svecica, sired by extra-pair males had a higher T-cell-mediated immune response than their maternal half-siblings raised in the same nest. The difference could not be attributed to nestling body mass, sex or hatching order, but may be an effect of paternal genotype. Extra-pair young were also more immunocompetent than their paternal half-sibs raised in the genetic father's own nest, which indicates an additional effect of maternal genotype. Our results are consistent with the idea that females engage in extra-pair copulations to obtain compatible viability genes, rather than 'good genes' per se.

Cooper Pairs in Insulators?

International Nuclear Information System (INIS)

Valles, James

2008-01-01

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.

Coherent Cooper pair tunneling in systems of Josephson junctions: effects of quasiparticle tunneling and of the electromagnetic environment

NARCIS (Netherlands)

Maassen van den Brink, A.; Odintsov, A.A.; Bobbert, P.A.; Schön, G.

1991-01-01

Small capacitance tunnel junctions show single electron effects and, in the superconducting state, the coherent tunneling of Cooper pairs. We study these effects in a system of two Josephson junctions, driven by a voltage source with a finite impedance. Novel features show up in theI–V

Envisaging quantum transport phenomenon in a muddled base pair of DNA

Science.gov (United States)

Vohra, Rajan; Sawhney, Ravinder Singh

2018-05-01

The effect of muddled base pair on electron transfer through a deoxyribonucleic acid (DNA) molecule connected to the gold electrodes has been elucidated using tight binding model. The effect of hydrogen and nitrogen bonds on the resistance of the base pair has been minutely observed. Using the semiempirical extended Huckel approach within NEGF regime, we have determined the current and conductance vs. bias voltage for disordered base pairs of DNA made of thymine (T) and adenine (A). The asymmetrical behaviour amid five times depreciation in the current characteristics has been observed for deviated Au-AT base pair-Au devices. An interesting revelation is that the conductance of the intrinsic AT base pair configuration attains dramatically high values with the symmetrical zig-zag pattern of current, which clearly indicates the transformation of the bond length within the strands of base pair when compared with other samples. A thorough investigation of the transmission coefficients T( E) and HOMO-LUMO gap reveals the misalignment of the strands in base pairs of DNA. The observed results present an insight to extend this work to build biosensing devices to predict the abnormality with the DNA.

Pairing effects in rotating nuclei: a semi classical approach

International Nuclear Information System (INIS)

Durand, M.

1985-10-01

The semi-classical phase-space distribution ρ(r,p) is calculated for rotating superfluid nuclei, taking into account the reaction of the pairing field to the rotational motion. Moments of inertia and current distributions calculated by means of this distribution pass continuously from a rigid to an irrotational behaviour

Isovector pairing effect on nuclear moment of inertia at finite temperature in N = Z even–even systems

International Nuclear Information System (INIS)

Ami, I.; Fellah, M.; Allal, N.H.; Benhamouda, N.; Oudih, M.R.; Belabbas, M.

2011-01-01

Expressions of temperature-dependent perpendicular (ℑ⊥) and parallel (ℑ‖) moments of inertia, including isovector pairing effects, have been established using the cranking method. They are derived from recently proposed temperature-dependent gap equations. The obtained expressions generalize the conventional finite-temperature BCS (FTBCS) ones. Numerical calculations have been carried out within the framework of the schematic Richardson model as well as for nuclei such as N = Z, using the single-particle energies and eigenstates of a deformed Woods–Saxon mean-field. ℑ⊥ and ℑ‖ have been studied as a function of the temperature. It has been shown that the isovector pairing effect on both the perpendicular and parallel moments of inertia is non-negligible at finite temperature. These correlations must thus be taking into account in studies of warm rotating nuclei in the N ≃ Z region. (author)

Observing Pair-Work Task in an English Speaking Class

Directory of Open Access Journals (Sweden)

Diana Achmad

2014-01-01

Full Text Available This paper reports on students’ pair-work interactions to develop their speaking skills in an ELT classroom which consisted of international learners. A number of 16 learners of intermediate proficiency with IELTS score band 5.5 were observed. The teacher had paired those he considered among them to be the more competent ones (hereafter, stronger with the less competent ones (hereafter, weaker; therefore, eight pairs were observed during the lesson. The task given to the students was to express ‘Agree and Disagree’ in the context of giving opinions related to social life. Based on the observations, the task was successfully implemented by six pairs; thus, the two others faced some problems. From the first pair, it was seen that the stronger student had intimated the weaker one into speaking during the task. The other pair, who was both of the same native, did not converse in English as expected and mostly used their native language to speak with one another presumably due to respect from the stronger student towards the weaker one. In situations like this, when pair-work becomes unproductive, rotating pairs is recommended to strengthen information sharing and assigning roles to avoid a student from taking over the activity from his or her pair. In conclusion, pairing international learners with mixed speaking proficiency by teachers must be conducted as effectively as possible by initially identifying their ability and learning culture to profoundly expand the students’ language resources.

Nuclear level densities with pairing and self-consistent ground-state shell effects

CERN Document Server

Arnould, M

1981-01-01

Nuclear level density calculations are performed using a model of fermions interacting via the pairing force, and a realistic single particle potential. The pairing interaction is treated within the BCS approximation with different pairing strength values. The single particle potentials are derived in the framework of an energy-density formalism which describes self-consistently the ground states of spherical nuclei. These calculations are extended to statistically deformed nuclei, whose estimated level densities include rotational band contributions. The theoretical results are compared with various experimental data. In addition, the level densities for several nuclei far from stability are compared with the predictions of a back-shifted Fermi gas model. Such a comparison emphasizes the possible danger of extrapolating to unknown nuclei classical level density formulae whose parameter values are tailored for known nuclei. (41 refs).

Pairing Courses across the Disciplines: Effects on Writing Performance

Science.gov (United States)

Watts, Julie; Burnett, Rebecca E.

2012-01-01

Writing performance of a complex recommendation report produced by student teams for an actual client during a 15-week semester was compared in a writing-intensive Agronomy 356 course and in paired Agronomy 356/English 309 courses. The longitudinal study investigated differences that existed between reports produced for each learning environment…

Investigating the connections between health lean management and clinical risk management.

Science.gov (United States)

Crema, Maria; Verbano, Chiara

2015-01-01

The purpose of this paper is to investigate connections and overlaps between health lean management (HLM) and clinical risk management (CRM) understanding whether and how these two approaches can be combined together to pursue efficiency and patient safety improvements simultaneously. A systematic literature review has been carried out. Searching in academic databases, papers that focus not only on HLM, but also on clinical errors and risk reduction, were included. The general characteristics of the selected papers were analysed and a content analysis was conducted. In most of the papers, pursing objectives of HLM and CRM and adopting tools and practices of both approaches, results of quality and, particularly, of safety improvements were obtained. A two-way arrow between HLM and CRM emerged but so far, none of the studies has been focused on the relationship between HLM and CRM. Results highlight an emerging research stream, with many useful theoretical and practical implications and opportunities for further research.

Effects of ion strength and ion pairing on (plant-wide) modelling of anaerobic digestion processes

DEFF Research Database (Denmark)

Flores-Alsina, Xavier; Mbamba, Christian Kazadi; Solon, Kimberly

2014-01-01

the effects that an improved physico-chemical description will have on the predicted effluent quality (EQI) and operational cost (OCI) indices. The acid-base equilibria implemented in the Anaerobic Digestion Model No.1 (ADM1) are modified to account for non-ideal aqueous-phase chemistry. The model corrects......The objective of this study is to show the influence of ionic strength (as activity corrections) andion pairing on (plant-wide) modelling of anaerobic digestion processes in wastewater treatment plants(WWTPs). Using the Benchmark Simulation Model No. 2 (BSM2) as a case study, this paper presents...... for ionic strength via the Davies approach to consider chemical activities instead of molar concentrations. Also, a speciation sub-routine based on a multi-dimensional Newton-Raphson iteration method accounts for the formation of some of the ion pairs playing an important role in wastewater treatment...

Effect of single-particle splitting in the exact wave function of the isovectorial pairing Hamiltonian

International Nuclear Information System (INIS)

Lerma H, S.

2010-01-01

The structure of the exact wave function of the isovectorial pairing Hamiltonian with nondegenerate single-particle levels is discussed. The way that the single-particle splittings break the quartet condensate solution found for N=Z nuclei in a single degenerate level is established. After a brief review of the exact solution, the structure of the wave function is analyzed and some particular cases are considered where a clear interpretation of the wave function emerges. An expression for the exact wave function in terms of the isospin triplet of pair creators is given. The ground-state wave function is analyzed as a function of pairing strength, for a system of four protons and four neutrons. For small and large values of the pairing strength a dominance of two-pair (quartets) scalar couplings is found, whereas for intermediate values enhancements of the nonscalar couplings are obtained. A correlation of these enhancements with the creation of Cooper-like pairs is observed.

Inhomogeneous ensembles of radical pairs in chemical compasses

Science.gov (United States)

Procopio, Maria; Ritz, Thorsten

2016-11-01

The biophysical basis for the ability of animals to detect the geomagnetic field and to use it for finding directions remains a mystery of sensory biology. One much debated hypothesis suggests that an ensemble of specialized light-induced radical pair reactions can provide the primary signal for a magnetic compass sensor. The question arises what features of such a radical pair ensemble could be optimized by evolution so as to improve the detection of the direction of weak magnetic fields. Here, we focus on the overlooked aspect of the noise arising from inhomogeneity of copies of biomolecules in a realistic biological environment. Such inhomogeneity leads to variations of the radical pair parameters, thereby deteriorating the signal arising from an ensemble and providing a source of noise. We investigate the effect of variations in hyperfine interactions between different copies of simple radical pairs on the directional response of a compass system. We find that the choice of radical pair parameters greatly influences how strongly the directional response of an ensemble is affected by inhomogeneity.

Effects of anomalous magnetic moment and temperature on pair production in an external magnetic field

International Nuclear Information System (INIS)

Dittrich, W.; Bauhoff, W.

1981-01-01

It is re-examined the problem of spontaneous pair creation in an external magnetic field. In contrast to earlier findings, it is shown that pair production does not occur due to the anomalous magnetic moment interaction. However, pairs may be observed in a situation of thermodynamic equilibrium at finite temperatures. (author)

Pair potentials in liquid metals

International Nuclear Information System (INIS)

Faber, T.E.

1980-01-01

The argument which justifies the use of a pair potential to describe the structure-dependent term in the energy of liquid metals is briefly reviewed. Because there is an additional term in the energy which depends upon volume rather than structure, and because the pair potential itself is volume-dependent, the relationship between pair potential and observable properties such as pressure, bulk modulus and pair distribution function is more complicated for liquid metals than it is for molecular liquids. Perhaps for this reason, the agreement between pair potentials inferred from observable properties and pair potentials calculated by means of pseudo-potential theory is still far from complete. The pair potential concept is applicable only to simple liquid metals, in which the electron-ion interaction is weak. No attempt is made to discuss liquid transition and rare-earth metals, which are not simple in this sense. (author)

ETHICAL LEADERSHIP AND EMPLOYEE VOICE: EMPLOYEE SELF-EFFICACY AND SELF-IMPACT AS MEDIATORS.

Science.gov (United States)

Wang, Duanxu; Gan, Chenjing; Wu, Chaoyan; Wang, Danqi

2015-06-01

Previous studies have used social learning theory to explain the influence of ethical leadership. This study continues the previous research by using social learning theory to explain the mediating effect of self-efficacy on the relationship between ethical leadership and employee voice. In addition, this study extends previous studies by introducing expectancy theory to explore whether self-impact also mediates the relationship between ethical leadership and employee voice. Ethical leadership, self-efficacy, self-impact, and employee voice were assessed using paired surveys among 59 supervisors and 295 subordinates employed at nine firms in the People's Republic of China. Using HLM and SEM analyses, the results revealed that ethical leadership was positively related to employee voice and that this relationship was partially mediated by both self-efficacy and self-impact.

Effects of noninstantaneous nonlinear processes on photon-pair generation by spontaneous four-wave mixing

DEFF Research Database (Denmark)

Koefoed, Jacob Gade; Christensen, Jesper Bjerge; Rottwitt, Karsten

2017-01-01

We present a general model, based on a Hamiltonian approach, for the joint quantum state of photon pairs generated through pulsed spontaneous four-wave mixing, including nonlinear phase modulation and a finite material response time. For the case of a silica fiber, it is found that the pair......-production rate depends weakly on the waveguide temperature, due to higher-order Raman scattering events, and more strongly on pump-pair frequency detuning. From the analytical model, a numerical scheme is derived, based on the well-known split-step method. This scheme allows computation of joint states where......-dependent change in quantum-mechanical purity may be observed in silica. This shows that Raman scattering not only introduces noise, but can also drastically change the spectral correlations in photon pairs when pumped with short pulses....

Emotional conflict occurs at a late stage: evidence from the paired-picture paradigm

Directory of Open Access Journals (Sweden)

Pan Fada

2016-01-01

Full Text Available The present study used paired-picture paradigm, where either congruent or incongruent emotional expressions were presented side by side to measure the neural correlates underlying the processing of emotional conflict effect. Event-related potentials were recorded while participants identified whether the valences of the paired-picture were consistent or not. The results showed that incongruent and congruent picture pairs both elicited larger N2 (210-310 ms amplitudes than neutral pairs. In contrast, the conflict picture pairs elicited a larger conflict slow potential (conflict SP, 700-1000 ms than did the positive and neutral picture pairs. There was no significant difference in conflict SP amplitudes between incongruent and congruent picture pairs (i.e., the mean amplitudes of negative and positive picture pairs. The results demonstrated that emotional information was identified and processed during the stage from about 210 ms to 310 ms. However, the emotional conflict effect did not appear until late stage (700-1000 ms. These results supported the distributed attention theory of emotions (DATE.

Electron-positron pair production in ultrastrong laser fields

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Bai Song Xie

2017-09-01

Full Text Available Electron–positron pair production due to the decay of vacuum in ultrastrong laser fields is an interesting topic which is revived recently because of the rapid development of current laser technology. The theoretical and numerical research progress of this challenging topic is reviewed. Many new findings are presented by different approaches such as the worldline instantons, the S-matrix theory, the kinetic method by solving the quantum Vlasov equation or/and the real-time Dirac–Heisenberg–Wigner formalism, the computational quantum field theory by solving the Dirac equation and so on. In particular, the effects of electric field polarizations on pair production are unveiled with different patterns of created momentum spectra. The effects of polarizations on the number density of created particles and the nonperturbative signatures of multiphoton process are also presented. The competitive interplay between the multiphoton process and nonperturbation process plays a key role in these new findings. These newly discovered phenomena are valuable to deepen the understanding of pair production in complex fields and even have an implication to the study of strong-field ionization. More recent studies on the pair production in complex fields as well as beyond laser fields are briefly presented in the view point of perspective future.

STUDI KOMPARATIF MODEL PEMBELAJARAN THINK PAIR SQUARE DAN THINK PAIR SHARE TERHADAP MOTIVASI DAN HASIL BELAJAR SISWA MAPEL TIK KELAS X SMA N 1 SUKASADA

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Putu Deli Januartini

2016-10-01

Abstract The purpose of this study were to determine (1 the significant influence of the application of think pair square and think pair share learning model on student’s learning achievement, (2 better learning achievement between think pair square and think pair share learning model, (3 student’s motivation, (4 the student’s responses. The research was a quasi-experimental design experiment with post test only control group design. The population of study was all the students in grade X. The sample were as X1 class with the application of Think Pair Square learning model, X3 class with the application of Think Pair Share learning model, and X5 class with the application of Direct Instruction learning model. The data was collected by cognitive and psychomotor tests. The student’s learning achievement were analyzed by the prerequisite test with the results of the three groups at normal distribution and homogenous, and the hypothesis tested by One Way Anova which means there is a significant effect on the application of think pair square, think pair share, and direct instruction learning models. Then it was conducted a further test t-Scheffe with the results there are differences in the learning achievement between think pair square, think pair share, and direct instruction learning models. According to the average result we made a conclusion that Think Pair Square was better learning models with higher student’s learning achievement. The questionnaires results shows that Think Pair Square was very high positive response and very high learning motivation, Think Pair Share was high positive response and very high learning motivation.   Keywords :   Think Pair Square, Think Pair Share, Direct Instruction, learning achievement, learning motivation, and student response.

Solvent and ion-pairing effects on the chlorine kinetic isotope effect of t-butyl chloride

International Nuclear Information System (INIS)

McCord, B.R.

1986-01-01

The solvolysis of t-butyl chloride and 1-adamantyl chloride was measured in mixtures of aqueous 2,2,2-trifluoroethanols and in mixtures of aqueous ethanols. The KIEs for t-butyl chloride at 25 0 C in 94% TFE/water, and 60% ethanol/water (solvent mixtures with similar polarity) were 1.0097 and 1.0104 respectively. Further investigations showed a KIE of 1.0104 in 50% ethanol/water and 1.0105 in 100% ethanol while the isotope effect in the fluorinated ethanols rose from 1.0094 in 99% TFE/water to 1.0101 in 70% ethanol/water. The KIE in all these solvents were shown to be directly proportional to the nucleophilicity of the solvent and indicates nucleophilic attack on an ion pair. The similar KIE of t-butyl chloride in the ethanol/water solvents was found to support the contention that solvent polarity exerts a minimal effect on the chlorine KIE

Pulsar Pair Cascades in Magnetic Fields with Offset Polar Caps

Science.gov (United States)

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.

Radiation- and pair-loaded shocks

Science.gov (United States)

Lyutikov, Maxim

2018-06-01

We consider the structure of mildly relativistic shocks in dense media, taking into account the radiation and pair loading, and diffusive radiation energy transfer within the flow. For increasing shock velocity (increasing post-shock temperature), the first important effect is the efficient energy redistribution by radiation within the shock that leads to the appearance of an isothermal jump, whereby the flow reaches the final state through a discontinuous isothermal transition. The isothermal jump, on scales much smaller than the photon diffusion length, consists of a weak shock and a quick relaxation to the isothermal conditions. Highly radiation-dominated shocks do not form isothermal jump. Pair production can mildly increase the overall shock compression ratio to ≈10 (4 for matter-dominated shocks and 7 of the radiation-dominated shocks).

Facilitating Social Play for Children with PDDs: Effects of Paired Robotic Devices

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Soichiro Matsuda

2017-06-01

Full Text Available Interacting with toys and other people is fundamental for developing social communication skills. However, children with autism spectrum disorder (ASD are characterized by having a significant impairment in social interaction, which often leads to deficits in play skills. For this reason, methods of teaching play skills to young children with ASD have been well documented. Although previous studies have examined a variety of instructional strategies for teaching skills, few studies have evaluated the potential of using robotic devices. The purpose of the present study is to examine whether automatic feedback provided by colored lights and vibration via paired robotic devices, COLOLO, facilitates social play behaviors in children with ASD. We also explore how social play relates to social interaction. COLOLO is a system of paired spherical devices covered with soft fabric. All participants in this study were recruited as volunteers through the Department of Psychology at Keio University. The pilot study included three participants diagnosed with Pervasive Developmental Disorders (PDDs; 5- to 6-year-old boys, and compared experimental conditions with and without automatic feedback from the devices (colored lights and vibration. The results indicated that the participants in the condition that included feedback from the devices exhibited increased rates of ball contact and looking at the therapist’s ball, but did not exhibit increased rates of eye contact or positive affect. In the experimental study, a systematic replication of the pilot study was performed with three other participants diagnosed with PDDs (3- to 6-year-old boys, using an A-B-A-B design. Again, the results demonstrated that, in the condition with colored lights and vibration, the children increased ball contact as well as looking at the therapist’s ball. However, the results did not show the effect of automatic feedback consistently for three children. These findings are

Effect of exciton pairing on the stationary Josephson current in superconductor-semimetal-superconductor junctions

International Nuclear Information System (INIS)

Itskovich, I.F.; Shekhter, R.I.

1983-01-01

The effect of exciton pairing of charge carriers in a semimetal on the stationary Josephson current in superconductor-semimetal-superconductor junctions is considered. It is shown that the phase transition of the semimetal interlayer into an exciton dielectric state for T/sub γ/< T/sub c/ (T/sub γ/, T/sub c/ are the superconducting and exciton transition temperatures, respectively) is accompanied by a kink on the critical current j/sub c/ versus temperature curve at the point T = T/sub γ/. A sharp nonmonotonic temperature dependence of the reduced current j/sub c//j/sub c/0 (j/sub c/0 is the critical current at T/sub γ/ = 0) is also possible in the range T< T/sub γ/. At low temperatures T<< v/sub 1,2//d<< T/sub γ/ (v/sub 1,2/ are the Fermi velocities of the carriers in the semimetal, d is the thickness of the interlayer) the critical current of the superconductor-semimetal-superconductor junction is exponentially smaller than the current in the absence of exciton pairing

Electron-positron pair production by two identical photons in the nuclear field

International Nuclear Information System (INIS)

Smirnov, A.I.

1977-01-01

In the Born approximation of the perturbation theory considered is a nonlinear effect of the electron-positron pair production by two identical photons in the Coulomb field of an atomic nucleus. The kinematic version of identical photons is studied. All the particles are considered to be nonpolarized. The calculation of the differential probability of the effect has been carried out earlier by the Feynman method. The total probability of the effect in limiting energy ranges is determined by integrating the formulas of the pair component distribution over energies. The probabilities of the electron-positron pair production and fusion of two photons into one in the nucleus field have been compared for the case of identical quanta. From the comparison of the results of analyzing both the nonlinear effects it follows that in the high-energy range the electron-positron pair production by two identical photons in the nucleus field extremely predominates over the fusion of two photons into one photon in the same field

Quantitative evaluation of pairs and RS steganalysis

Science.gov (United States)

Ker, Andrew D.

2004-06-01

We give initial results from a new project which performs statistically accurate evaluation of the reliability of image steganalysis algorithms. The focus here is on the Pairs and RS methods, for detection of simple LSB steganography in grayscale bitmaps, due to Fridrich et al. Using libraries totalling around 30,000 images we have measured the performance of these methods and suggest changes which lead to significant improvements. Particular results from the project presented here include notes on the distribution of the RS statistic, the relative merits of different "masks" used in the RS algorithm, the effect on reliability when previously compressed cover images are used, and the effect of repeating steganalysis on the transposed image. We also discuss improvements to the Pairs algorithm, restricting it to spatially close pairs of pixels, which leads to a substantial performance improvement, even to the extent of surpassing the RS statistic which was previously thought superior for grayscale images. We also describe some of the questions for a general methodology of evaluation of steganalysis, and potential pitfalls caused by the differences between uncompressed, compressed, and resampled cover images.

Probing ion-specific effects on aqueous acetate solutions: Ion pairing versus water structure modifications.

Science.gov (United States)

Petit, Tristan; Lange, Kathrin M; Conrad, Gerrit; Yamamoto, Kenji; Schwanke, Christoph; Hodeck, Kai F; Dantz, Marcus; Brandenburg, Tim; Suljoti, Edlira; Aziz, Emad F

2014-05-01

The effect of monovalent cations (Li(+), K(+), NH4 (+), Na(+)) on the water structure in aqueous chloride and acetate solutions was characterized by oxygen K-edge X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy, and resonant inelastic X-ray scattering (RIXS) of a liquid microjet. We show ion- and counterion dependent effects on the emission spectra of the oxygen K-edge, which we attribute to modifications of the hydrogen bond network of water. For acetates, ion pairing with carboxylates was also probed selectively by XAS and RIXS. We correlate our experimental results to speciation data and to the salting-out properties of the cations.

Probing ion-specific effects on aqueous acetate solutions: Ion pairing versus water structure modifications

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Tristan Petit

2014-05-01

Full Text Available The effect of monovalent cations (Li+, K+, NH4+, Na+ on the water structure in aqueous chloride and acetate solutions was characterized by oxygen K-edge X-ray absorption spectroscopy (XAS, X-ray emission spectroscopy, and resonant inelastic X-ray scattering (RIXS of a liquid microjet. We show ion- and counterion dependent effects on the emission spectra of the oxygen K-edge, which we attribute to modifications of the hydrogen bond network of water. For acetates, ion pairing with carboxylates was also probed selectively by XAS and RIXS. We correlate our experimental results to speciation data and to the salting-out properties of the cations.

Excited cooper pairs

Energy Technology Data Exchange (ETDEWEB)

Lopez-Arrietea, M. G.; Solis, M. A.; De Llano, M. [Universidad Nacional Autonoma de Mexico, Mexico, D.F (Mexico)

2001-02-01

Excited cooper pairs formed in a many-fermion system are those with nonzero total center-of mass momentum (CMM). They are normally neglected in the standard Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity for being too few compared with zero CMM pairs. However, a Bose-Einstein condensation picture requires both zero and nonzero CMM pairs. Assuming a BCS model interaction between fermions we determine the populations for all CMM values of Cooper pairs by actually calculating the number of nonzero-CMM pairs relative to that of zero-CMM ones in both 2D and 3D. Although this ratio decreases rapidly with CMM, the number of Cooper pairs for any specific CMM less than the maximum (or breakup of the pair) momentum turns out to be typically larger than about 95% of those with zero-CMM at zero temperature T. Even at T {approx}100 K this fraction en 2D is still as large as about 70% for typical quasi-2D cuprate superconductor parameters. [Spanish] Los pares de cooper excitados formados en un sistema de muchos electrones, son aquellos con momentos de centro de masa (CMM) diferente de cero. Normalmente estos no son tomados en cuenta en la teoria estandar de la superconductividad de Bardeen-Cooper-Schrieffer (BCS) al suponer que su numero es muy pequeno comparados con los pares de centro de masa igual a cero. Sin embargo, un esquema de condensacion Bose-Einstein requiere de ambos pares, con CMM cero y diferente de cero. Asumiendo una interaccion modelo BCS entre los fermiones, determinamos la poblacion de pares cooper con cada uno de todos los posibles valores del CMM calculando el numero de pares con momentos de centro de masa diferente de cero relativo a los pares de CMM igual a cero, en 2D y 3D. Aunque esta razon decrece rapidamente con el CMM, el numero de pares de cooper para cualquier CMM especifico menor que el momento maximo (o rompimiento de par) es tipicamente mas grande que el 95% de aquellos con CMM cero. Aun a T {approx}100 K esta fraccion en 2D es

Nuclear pairing reduction due to rotation and blocking

International Nuclear Information System (INIS)

Wu Xi; Zhang Zhenhua; Lei Yi'an; Zeng Jinyan

2010-01-01

Nuclear pairing gaps of well-deformed and superdeformed nuclei are investigated using the particle-number conserving (PNC) formalism for the cranked shell model, in which the blocking effects are treated exactly and no spurious states appear. Both the rotational frequency ω-dependence and seniority ν-dependence of the pairing gap Δ-bar are addressed. For the ground-state bands of even-even nuclei, PNC calculations show that in general Δ-bar decreases with increasing ω, but the ω-dependence is much weaker than that calculated by the number-projected Hartree-Fock-Bogolyubov (NHFB) approach. For the multi quasiparticle bands (seniority ν > 2), the pairing gaps keep almost ω-independent. As a function of the seniority ν, the bandhead pairing gaps Δ-bar (ν, ω = 0) decrease slowly with increasing ν. Even for the highest seniority ν bands identified so far, Δ-bar (ν, ω = 0) keep 70% larger than Δ-bar (ν = 0, ω = 0). (authors)

Nuclear pairing reduction due to rotation and blocking

International Nuclear Information System (INIS)

Wu, X.; Zhang, Z. H.; Zeng, J. Y.; Lei, Y. A.

2011-01-01

Nuclear pairing gaps of normally deformed and superdeformed nuclei are investigated using the particle-number-conserving (PNC) formalism for the cranked shell model, in which the blocking effects are treated exactly. Both rotational frequency ω dependence and seniority (number of unpaired particles) ν dependence of the pairing gap Δ-tilde are investigated. For the ground-state bands of even-even nuclei, PNC calculations show that, in general, Δ-tilde decreases with increasing ω, but the ω dependence is much weaker than that calculated by the number-projected Hartree-Fock-Bogolyubov approach. For the multiquasiparticle bands (seniority ν>2), the pairing gaps stay almost ω independent. As a function of the seniority ν, the bandhead pairing gaps Δ-tilde(ν,ω=0) decrease slowly with increasing ν. Even for the highest seniority ν bands identified so far, Δ-tilde(ν,ω=0) remains greater than 70% of Δ-tilde(ν=0,ω=0).

Extra-pair mating and evolution of cooperative neighbourhoods.

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Sigrunn Eliassen

Full Text Available 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.

Particle-number conservation in odd mass proton-rich nuclei in the isovector pairing case

International Nuclear Information System (INIS)

Fellah, M.; Allal, N.H.; Oudih, M.R.

2015-01-01

An expression of a wave function which describes odd–even systems in the isovector pairing case is proposed within the BCS approach. It is shown that it correctly generalizes the one used in the pairing between like-particles case. It is then projected on the good proton and neutron numbers using the Sharp-BCS (SBCS) method. The expressions of the expectation values of the particle-number operator and its square, as well as the energy, are deduced in both approaches. The formalism is applied to study the isovector pairing effect and the number projection one on the ground state energy of odd mass N ≈ Z nuclei using the single-particle energies of a deformed Woods–Saxon mean-field. It is shown that both effects on energy do not exceed 2%, however, the absolute deviations may reach several MeV. Moreover, the np pairing effect rapidly diminishes as a function of (N - Z). The deformation effect is also studied. It is shown that the np pairing effect, either before or after the projection, as well as the projection effect, when including or not the isovector pairing, depends upon the deformation. However, it seems that the predicted ground state deformation will remain the same in the four approaches. (author)

Mesoscopic pairing without superconductivity

Science.gov (United States)

Hofmann, Johannes

2017-12-01

We discuss pairing signatures in mesoscopic nanowires with a variable attractive pairing interaction. Depending on the wire length, density, and interaction strength, these systems realize a simultaneous bulk-to-mesoscopic and BCS-BEC crossover, which we describe in terms of the parity parameter that quantifies the odd-even energy difference and generalizes the bulk Cooper pair binding energy to mesoscopic systems. We show that the parity parameter can be extracted from recent measurements of conductance oscillations in SrTiO3 nanowires by Cheng et al. [Nature (London) 521, 196 (2015), 10.1038/nature14398], where it marks the critical magnetic field that separates pair and single-particle currents. Our results place the experiment in the fluctuation-dominated mesoscopic regime on the BCS side of the crossover.

Effect of socioeconomic inequalities on cholecystectomy outcomes: a 10-year population-based analysis.

Science.gov (United States)

Lu, Ping; Yang, Nan-Ping; Chang, Nien-Tzu; Lai, K Robert; Lin, Kai-Biao; Chan, Chien-Lung

2018-02-13

Although numerous epidemiological studies on cholecystectomy have been conducted worldwide, only a few have considered the effect of socioeconomic inequalities on cholecystectomy outcomes. Specifically, few studies have focused on the low-income population (LIP). A nationwide prospective study based on the Taiwan National Health Insurance dataset was conducted during 2003-2012. The International Classification of ICD-9-CM procedure codes 51.2 and 51.21-51.24 were identified as the inclusion criteria for cholecystectomy. Temporal trends were analyzed using a joinpoint regression, and the hierarchical linear modeling (HLM) method was used as an analytical strategy to evaluate the group-level and individual-level factors. Interactions between age, gender and SES were also tested in HLM model. Analyses were conducted on 225,558 patients. The incidence rates were 167.81 (95% CI: 159.78-175.83) per 100,000 individuals per year for the LIP and 123.24 (95% CI: 116.37-130.12) per 100,000 individuals per year for the general population (GP). After cholecystectomy, LIP patients showed higher rates of 30-day mortality, in-hospital complications, and readmission for complications, but a lower rate of routine discharge than GP patients. The hospital costs and length of stay for LIP patients were higher than those for GP patients. The multilevel analysis using HLM revealed that adverse socioeconomic status significantly negatively affects the outcomes of patients undergoing cholecystectomy. Additionally, male sex, advanced age, and high Charlson Comorbidity Index (CCI) scores were associated with higher rates of in-hospital complications and 30-day mortality. We also observed that the 30-day mortality rates for patients who underwent cholecystectomy in regional hospitals and district hospitals were significantly higher than those of patients receiving care in a medical center. Patients with a disadvantaged finance status appeared to be more vulnerable to cholecystectomy surgery

An effective approach for identification of in vivo protein-DNA binding sites from paired-end ChIP-Seq data

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Wilson Zoe A

2010-02-01

Full Text Available Abstract Background ChIP-Seq, which combines chromatin immunoprecipitation (ChIP with high-throughput massively parallel sequencing, is increasingly being used for identification of protein-DNA interactions in vivo in the genome. However, to maximize the effectiveness of data analysis of such sequences requires the development of new algorithms that are able to accurately predict DNA-protein binding sites. Results Here, we present SIPeS (Site Identification from Paired-end Sequencing, a novel algorithm for precise identification of binding sites from short reads generated by paired-end solexa ChIP-Seq technology. In this paper we used ChIP-Seq data from the Arabidopsis basic helix-loop-helix transcription factor ABORTED MICROSPORES (AMS, which is expressed within the anther during pollen development, the results show that SIPeS has better resolution for binding site identification compared to two existing ChIP-Seq peak detection algorithms, Cisgenome and MACS. Conclusions When compared to Cisgenome and MACS, SIPeS shows better resolution for binding site discovery. Moreover, SIPeS is designed to calculate the mappable genome length accurately with the fragment length based on the paired-end reads. Dynamic baselines are also employed to effectively discriminate closely adjacent binding sites, for effective binding sites discovery, which is of particular value when working with high-density genomes.

PandA : pairings and arithmetic

NARCIS (Netherlands)

Chuengsatiansup, C.; Naehrig, M.; Ribarski, P.; Schwabe, P.; Cao, Z.; Zhang, F.

2014-01-01

This paper introduces PandA, a software framework for Pairings and Arithmetic. It is designed to bring together advances in the efficient computation of cryptographic pairings and the development and implementation of pairing-based protocols. The intention behind the PandA framework is to give

An effective pair potential for liquid semiconductor, Se: Structure and ...

Indian Academy of Sciences (India)

This model potential is then used to describe through low-order perturbation theory, the structure and related dynamical properties like self-diffusion coefficient and shear viscosity of this complex liquid over a wide range of temperatures. Keywords. Liquid semiconductor; pair potential; structure and dynamical properties.

NNLL momentum-space resummation for stop-pair production at the LHC

International Nuclear Information System (INIS)

Broggio, Alessandro; Ferroglia, Andrea; Neubert, Matthias; Vernazza, Leonardo; Yang, Li Lin

2014-01-01

If supersymmetry near the TeV scale is realized in Nature, the pair production of scalar top squarks is expected to be observable at the Large Hadron Collider. Recently, effective field-theory methods were employed to obtain approximate predictions for the cross section for this process, which include soft-gluon emission effects up to next-to-next-to-leading order (NNLO) in perturbation theory. In this work we employ the same techniques to resum soft-gluon emission effects to all orders in perturbation theory and with next-to-next-to-logarithmic (NNLL) accuracy. We analyze the effects of NNLL resummation on the stop-pair production cross section by obtaining NLO+NNLL predictions in pair invariant mass and one-particle inclusive kinematics. We compare the results of these calculations to the approximate NNLO predictions for the cross sections

NNLL momentum-space resummation for stop-pair production at the LHC

Energy Technology Data Exchange (ETDEWEB)

Broggio, Alessandro [Paul Scherrer Institute,CH-5232 Villigen (Switzerland); Ferroglia, Andrea [New York City College of Technology, The City University of New York,300 Jay Street, Brooklyn, NY 11201 (United States); Neubert, Matthias [PRISMA Cluster of Excellence & Mainz Institut for Theoretical Physics,Johannes Gutenberg University, D-55099 Mainz (Germany); Department of Physics, LEPP, Cornell University,Ithaca, NY 14853 (United States); Vernazza, Leonardo [Dipartimento di Fisica, Università di Torino & INFN - Sezione di Torino,Via P. Giuria 1, I-10125 Torino (Italy); Yang, Li Lin [School of Physics and State Key Laboratory of Nuclear Physics and Technology,Peking University, 100871 Beijing (China); Collaborative Innovation Center of Quantum Matter,Beijing (China); Center for High Energy Physics, Peking University,Beijing 100871 (China)

2014-03-12

If supersymmetry near the TeV scale is realized in Nature, the pair production of scalar top squarks is expected to be observable at the Large Hadron Collider. Recently, effective field-theory methods were employed to obtain approximate predictions for the cross section for this process, which include soft-gluon emission effects up to next-to-next-to-leading order (NNLO) in perturbation theory. In this work we employ the same techniques to resum soft-gluon emission effects to all orders in perturbation theory and with next-to-next-to-logarithmic (NNLL) accuracy. We analyze the effects of NNLL resummation on the stop-pair production cross section by obtaining NLO+NNLL predictions in pair invariant mass and one-particle inclusive kinematics. We compare the results of these calculations to the approximate NNLO predictions for the cross sections.

Lax pairs: a novel type of separability

International Nuclear Information System (INIS)

Fokas, A S

2009-01-01

An attempt is made to place into historical context the fundamental concept of Lax pairs. For economy of presentation, emphasis is placed on the effectiveness of Lax pairs for the analysis of integrable nonlinear evolution PDEs. It is argued that Lax pairs provide a deeper type of separability than the classical separation of variables. Indeed, it is shown that: (a) the solution of the Cauchy problem of evolution equations is based on the derivation of a nonlinear Fourier transform pair, and this is achieved by employing the spectral analysis of one of the two eigenvalue equations forming a Lax pair; thus, although this methodology still follows the reverent philosophy of the classical separation of variables and transform methods, it can be applied to a class of nonlinear PDEs. (b) The solution of initial-boundary-value problems of evolution equations is based on the simultaneous spectral analysis of both equations forming a Lax pair and hence, in a sense, it employs the synthesis instead of the separation of variables; this methodology does not have a direct classical analogue, however, it can be considered as the nonlinearization of a method which combines Green's function classical integral representations with an analogue of the method of images, but which are now formulated in the spectral (Fourier) instead of the physical space. In addition to presenting a general methodology for analysing initial- and initial-boundary-value problems for nonlinear integrable evolution equations in one and two spatial variables, recent progress is reviewed for the derivation and the solution of integrable nonlinear evolution PDEs formulated in higher than two spatial dimensions. (topical review)

Pair production in semiclassical and quantum-field theoretical description; Paarerzeugung in semiklassischer und quantenfeldtheoretischer Beschreibung

Energy Technology Data Exchange (ETDEWEB)

Woellert, Anton

2016-07-27

Pair production of electron-positron pairs in ultra-intense laser fields is considered in this work. Two regimes are investigated separately. The first regime is the so-called tunnel regime of pair production. The existing tunneling picture which is applicable in this regime will be enhanced by the effects of a magnetic field and an additional, perturbatively treated photon. Both effects are incorporated by the semi-classical approximation. In contrast, no straightforward approach exists so far for the second regime of pair production. Therefore, numerical calculations will be carried out by applying the framework of the in/out-formalism in external fields. These simulations show non-trivial effects that are be expected in this regime. Specifically, the influence of the electromagnetic fields' polarization upon the produced pair spectra is investigated. Furthermore, multi-pair states are studied.

Top-quark pair production at hadron colliders

Energy Technology Data Exchange (ETDEWEB)

Ahrens, Valentin

2011-12-08

In this thesis we investigate several phenomenologically important properties of top-quark pair production at hadron colliders. We calculate double differential cross sections in two different kinematical setups, pair invariant-mass (PIM) and single-particle inclusive (1PI) kinematics. In pair invariant-mass kinematics we are able to present results for the double differential cross section with respect to the invariant mass of the top-quark pair and the top-quark scattering angle. Working in the threshold region, where the pair invariant mass M is close to the partonic center-of-mass energy {radical}(s), we are able to factorize the partonic cross section into different energy regions. We use renormalization-group (RG) methods to resum large threshold logarithms to next-to-next-to-leading-logarithmic (NNLL) accuracy. On a technical level this is done using effective field theories, such as heavy-quark effective theory (HQET) and soft-collinear effective theory (SCET). The same techniques are applied when working in 1PI kinematics, leading to a calculation of the double differential cross section with respect to transverse-momentum pT and the rapidity of the top quark. We restrict the phase-space such that only soft emission of gluons is possible, and perform a NNLL resummation of threshold logarithms. The obtained analytical expressions enable us to precisely predict several observables, and a substantial part of this thesis is devoted to their detailed phenomenological analysis. Matching our results in the threshold regions to the exact ones at next-to-leading order (NLO) in fixed-order perturbation theory, allows us to make predictions at NLO+NNLL order in RG-improved, and at approximate next-to-next-to-leading order (NNLO) in fixed order perturbation theory. We give numerical results for the invariant mass distribution of the top-quark pair, and for the top-quark transverse-momentum and rapidity spectrum. We predict the total cross section, separately for both

Amperean Pairing and the Pseudogap Phase of Cuprate Superconductors

Science.gov (United States)

Lee, Patrick A.

2014-07-01

The enigmatic pseudogap phase in underdoped cuprate high-Tc superconductors has long been recognized as a central puzzle of the Tc problem. Recent data show that the pseudogap is likely a distinct phase, characterized by a medium range and quasistatic charge ordering. However, the origin of the ordering wave vector and the mechanism of the charge order is unknown. At the same time, earlier data show that precursive superconducting fluctuations are also associated with this phase. We propose that the pseudogap phase is a novel pairing state where electrons on the same side of the Fermi surface are paired, in strong contrast with conventional Bardeen-Cooper-Schrieffer theory which pairs electrons on opposite sides of the Fermi surface. In this state the Cooper pair carries a net momentum and belongs to a general class called pair density wave. The microscopic pairing mechanism comes from a gauge theory formulation of the resonating valence bond (RVB) picture, where spinons traveling in the same direction feel an attractive force in analogy with Ampere's effects in electromagnetism. We call this Amperean pairing. Charge order automatically appears as a subsidiary order parameter even when long-range pair order is destroyed by phase fluctuations. Our theory gives a prediction of the ordering wave vector which is in good agreement with experiment. Furthermore, the quasiparticle spectrum from our model explains many of the unusual features reported in photoemission experiments. The Fermi arc, the unusual way the tip of the arc terminates, and the relation of the spanning vector of the arc tips to the charge ordering wave vector also come out naturally. Finally, we propose an experiment that can directly test the notion of Amperean pairing.

Effects of the R-parity violation in the minimal supersymmetric standard model on dilepton pair production at the CERN LHC

CERN Document Server

Jun, Y; Lang-Hui, W; Ren Zhao You; Jun, Yin; Wen-Gan, Ma; Lang-Hui, Wan; Ren-You, Zhang

2002-01-01

We investigate in detail the effects of the R-parity lepton number violation in the minimal supersymmetric standard model (MSSM) on the parent process $pp \\to e^+ e^- + X$ at the CERN Large Hadron Collider (LHC). The numerical comparisons between the contributions of the R-parity violating effects to the parent process via the Drell-Yan subprocess and the gluon-gluon fusion are made. We find that the R-violating effects on $e^+ e^-$ pair production at the LHC could be significant. The results show that the cross section of the $ e^+ e^-$ pair productions via gluon-gluon collision at the LHC can be of the order of $10^2$ fb, and this subprocess maybe competitive with the production mechanism via the Drell-Yan subprocess. We give also quantitatively the analysis of the effects from both the mass of sneutrino and coupling strength of the R-parity violating interactions.

Filipino au pairs on the move

DEFF Research Database (Denmark)

Dalgas, Karina Märcher

2016-01-01

Most Filipina au pairs in Denmark send remittances back home, and for many, au pairing forms part of longer-term migration trajectories. This article explores how Filipina au pairs try to carve out a future for themselves abroad. It shows that they navigate within tight webs of financial interdep......Most Filipina au pairs in Denmark send remittances back home, and for many, au pairing forms part of longer-term migration trajectories. This article explores how Filipina au pairs try to carve out a future for themselves abroad. It shows that they navigate within tight webs of financial...

Manipulability impairs association-memory: revisiting effects of incidental motor processing on verbal paired-associates.

Science.gov (United States)

Madan, Christopher R

2014-06-01

Imageability is known to enhance association-memory for verbal paired-associates. High-imageability words can be further subdivided by manipulability, the ease by which the named object can be functionally interacted with. Prior studies suggest that motor processing enhances item-memory, but impairs association-memory. However, these studies used action verbs and concrete nouns as the high- and low-manipulability words, respectively, confounding manipulability with word class. Recent findings demonstrated that nouns can serve as both high- and low-manipulability words (e.g., CAMERA and TABLE, respectively), allowing us to avoid this confound. Here participants studied pairs of words that consisted of all possible pairings of high- and low-manipulability words and were tested with immediate cued recall. Recall was worse for pairs that contained high-manipulability words. In free recall, participants recalled more high- than low-manipulability words. Our results provide further evidence that manipulability influences memory, likely occurring through automatic motor imagery. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of Sleep on Word Pair Memory in Children – Separating Item and Source Memory Aspects

Directory of Open Access Journals (Sweden)

Jing-Yi Wang

2017-09-01

Full Text Available Word paired-associate learning is a well-established task to demonstrate sleep-dependent memory consolidation in adults as well as children. Sleep has also been proposed to benefit episodic features of memory, i.e., a memory for an event (item bound into the spatiotemporal context it has been experienced in (source. We aimed to explore if sleep enhances word pair memory in children by strengthening the episodic features of the memory, in particular. Sixty-one children (8–12 years studied two lists of word pairs with 1 h in between. Retrieval testing comprised cued recall of the target word of each word pair (item memory and recalling in which list the word pair had appeared in (source memory. Retrieval was tested either after 1 h (short retention interval or after 11 h, with this long retention interval covering either nocturnal sleep or daytime wakefulness. Compared with the wake interval, sleep enhanced separate recall of both word pairs and the lists per se, while recall of the combination of the word pair and the list it had appeared in remained unaffected by sleep. An additional comparison with adult controls (n = 37 suggested that item-source bound memory (combined recall of word pair and list is generally diminished in children. Our results argue against the view that the sleep-induced enhancement in paired-associate learning in children is a consequence of sleep specifically enhancing the episodic features of the memory representation. On the contrary, sleep in children might strengthen item and source representations in isolation, while leaving the episodic memory representations (item-source binding unaffected.

PLASMA EFFECTS ON FAST PAIR BEAMS. II. REACTIVE VERSUS KINETIC INSTABILITY OF PARALLEL ELECTROSTATIC WAVES

International Nuclear Information System (INIS)

Schlickeiser, R.; Krakau, S.; Supsar, M.

2013-01-01

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 –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

The role of spatial organization in preference for color pairs.

Science.gov (United States)

Schloss, Karen B; Palmer, Stephen E

2011-01-01

We investigated how spatial organization influences color-pair preference asymmetries: differential preference for one color pair over another when the pairs contain the same colors in opposite spatial configurations. Schloss and Palmer (2011, Attention, Perception, & Psychophysics 73 55-571) found weak figure ground preference asymmetries for small squares centered on large squares in aesthetic ratings. Here, we found robust preference asymmetries using a more sensitive forced-choice task: participants strongly prefer pairs with yellower, lighter figures on bluer, darker grounds (experiment 1). We also investigated which spatial factors influence these preference asymmetries. Relative area of the two component regions is clearly important, and perceived 3-D area of the 2-D displays (ie after the ground is amodally completed behind the figure) is more influential than 2-D area (experiment 2). Surroundedness is not required, because yellowness blueness effects were comparable for pairs in which the figure was surrounded by the ground, and for mosaic arrangements in which the regions were adjacent and separated by a gap (experiment 3). Lightness darkness effects, however, were opposite for figure ground versus mosaic organizations: people prefer figure-ground organizations in which smaller regions are lighter, but prefer mosaic organizations in which smaller regions are darker. Physiological, phenomenological, and ecological explanations of the reported results are discussed.

Effect of housing relocation and neighborhood environment on adolescent mental and behavioral health.

Science.gov (United States)

Byck, Gayle R; Bolland, John; Dick, Danielle; Swann, Gregory; Henry, David; Mustanski, Brian

2015-11-01

This study examined whether relocating from a high-poverty neighborhood to a lower poverty neighborhood as part of a federal housing relocation program (HOPE VI; Housing Opportunities for People Everywhere) had effects on adolescent mental and behavioral health compared to adolescents consistently living in lower poverty neighborhoods. Sociodemographic, risk behavior, and neighborhood data were collected from 592 low-income, primarily African-American adolescents and their primary caregivers. Structured psychiatric interviews were conducted with adolescents. Prerelocation neighborhood, demographic, and risk behavior data were also included. Hierarchical Linear Modeling (HLM) was used to test associations between neighborhood variables and risk outcomes. HLM was used to test whether the effect of neighborhood relocation and neighborhood characteristics might explain differences in sexual risk taking, substance use, and mental health outcomes. Adolescents who relocated of HOPE VI neighborhoods (n = 158) fared worse than control group participants (n = 429) on most self-reported mental health outcomes. The addition of subjective neighborhood measures generally did not substantively change these results. Our findings suggest that moving from a high-poverty neighborhood to a somewhat lower poverty neighborhood is not associated with better mental health and risk behavior outcomes in adolescents. The continued effects of having grown up in a high-poverty neighborhood, the small improvements in their new neighborhoods, the comparatively short length of time they lived in their new neighborhood, and/or the stress of moving appears to worsen most of the mental health outcomes of HOPE VI compared to control group participants who consistently lived in the lower poverty neighborhoods. © 2015 Association for Child and Adolescent Mental Health.

Probing the pairing interaction through two-neutron transfer reactions

Directory of Open Access Journals (Sweden)

Margueron J.

2012-12-01

Full Text Available The treatment of the pairing interaction in mean-field-based models is addressed. In particular, the possibility to use pair transfers as A tool to better constrain this interaction is discussed. First, pairing inter-actions with various density dependencies (surface/volume mixing are used in the microscopic Hartree-Fock-Bogoliubov + quasiparticle random-phase approximation model to generate the form factors to be used in reaction calculations. Cross sections for (p,t two-neutron transfer reactions are calculated in the one-step zero-range distorted-wave Born approximation for some Tin isotopes and for incident proton energies from 15 to 35 MeV. Three different surface/volume mixings of A zero-range density-dependent pairing interaction are employed in the microscopic calculations and the sensitivity of the cross sections to the different mixings is analyzed. Differences among the three different theoretical predictions are found espacially for the nucleus 136Sn and they are more important at the incident proton energy of 15 MeV. We thus indicate (p,t two-neutron transfer reactions with very neutron-rich Sn isotopes and at proton energies around 15 MeV as good experimental cases where the surface/volume mixing of the pairing interaction may be probed. In the second part of the manuscript, ground-state to ground-state transitions are investigated. Approximations made to estimate two-nucleon transfer probabilities in ground-state to ground-state transitions and the physical interpretation of these probabilities are discussed. Probabilities are often calculated by approximating both ground states of the initial nucleus A and of the final nucleus A±2 by the same quasiparticle vacuum. We analyze two improvements of this approach. First, the effect of using two different ground states with average numbers of particles A and A±2 is quantified. Second, by using projection techniques, the role of particle number restoration is analyzed. Our analysis

Two-temperature accretion disks with electron-positron pairs - Effects of Comptonized external soft photons

Science.gov (United States)

Kusunose, Masaaki; Takahara, Fumio

1990-01-01

The present account of the effects of soft photons from external sources on two-temperature accretion disks in electron-positron pair equilibrium solves the energy-balance equation for a given radial distribution of the input rate of soft photons, taking into account their bremsstrahlung and Comptonization. Critical rate behavior is investigated as a function of the ratio of the energy flux of incident soft photons and the energy-generation rate. As in a previous study, the existence of a critical accretion rate is established.

Exotic superfluidity and pairing phenomena in atomic Fermi gases in mixed dimensions.

Science.gov (United States)

Zhang, Leifeng; Che, Yanming; Wang, Jibiao; Chen, Qijin

2017-10-11

Atomic Fermi gases have been an ideal platform for simulating conventional and engineering exotic physical systems owing to their multiple tunable control parameters. Here we investigate the effects of mixed dimensionality on the superfluid and pairing phenomena of a two-component ultracold atomic Fermi gas with a short-range pairing interaction, while one component is confined on a one-dimensional (1D) optical lattice whereas the other is in a homogeneous 3D continuum. We study the phase diagram and the pseudogap phenomena throughout the entire BCS-BEC crossover, using a pairing fluctuation theory. We find that the effective dimensionality of the non-interacting lattice component can evolve from quasi-3D to quasi-1D, leading to strong Fermi surface mismatch. Upon pairing, the system becomes effectively quasi-two dimensional in the BEC regime. The behavior of T c bears similarity to that of a regular 3D population imbalanced Fermi gas, but with a more drastic departure from the regular 3D balanced case, featuring both intermediate temperature superfluidity and possible pair density wave ground state. Unlike a simple 1D optical lattice case, T c in the mixed dimensions has a constant BEC asymptote.

A fast exact simulation method for a class of Markov jump processes.

Science.gov (United States)

Li, Yao; Hu, Lili

2015-11-14

A new method of the stochastic simulation algorithm (SSA), named the Hashing-Leaping method (HLM), for exact simulations of a class of Markov jump processes, is presented in this paper. The HLM has a conditional constant computational cost per event, which is independent of the number of exponential clocks in the Markov process. The main idea of the HLM is to repeatedly implement a hash-table-like bucket sort algorithm for all times of occurrence covered by a time step with length τ. This paper serves as an introduction to this new SSA method. We introduce the method, demonstrate its implementation, analyze its properties, and compare its performance with three other commonly used SSA methods in four examples. Our performance tests and CPU operation statistics show certain advantages of the HLM for large scale problems.

Higher order structural effects stabilizing the reverse watson-crick guanine-cytosine base pair in functional RNAs

KAUST Repository

Chawla, Mohit

2013-10-10

The G:C reverse Watson-Crick (W:W trans) base pair, also known as Levitt base pair in the context of tRNAs, is a structurally and functionally important base pair that contributes to tertiary interactions joining distant domains in functional RNA molecules and also participates in metabolite binding in riboswitches. We previously indicated that the isolated G:C W:W trans base pair is a rather unstable geometry, and that dicationic metal binding to the Guanine base or posttranscriptional modification of the Guanine can increase its stability. Herein, we extend our survey and report on other H-bonding interactions that can increase the stability of this base pair. To this aim, we performed a bioinformatics search of the PDB to locate all the occurencies of G:C trans base pairs. Interestingly, 66% of the G:C trans base pairs in the PDB are engaged in additional H-bonding interactions with other bases, the RNA backbone or structured water molecules. High level quantum mechanical calculations on a data set of representative crystal structures were performed to shed light on the structural stability and energetics of the various crystallographic motifs. This analysis was extended to the binding of the preQ1 metabolite to a preQ1-II riboswitch. 2013 The Author(s).

QSO Pairs across Active Galaxies

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... Several QSO pairs have been reported and their redshifts determined, where the two objects in each pair are located across an active galaxy. The usually accepted explanation of such occurrences is that the pair is ejected from the parent galaxy. Currently interpreted redshifted spectra for both the QSOs ...

Solvent effects on hydrogen bonds in Watson-Crick, mismatched, and modified DNA base pairs

NARCIS (Netherlands)

Poater, Jordi; Swart, Marcel; Guerra, Celia Fonseca; Bickelhaupt, F. Matthias

2012-01-01

We have theoretically analyzed a complete series of Watson–Crick and mismatched DNA base pairs, both in gas phase and in solution. Solvation causes a weakening and lengthening of the hydrogen bonds between the DNA bases because of the stabilization of the lone pairs involved in these bonds. We have

Suppression of bremsstrahlung and pair production due to environmental factors

International Nuclear Information System (INIS)

Klein, Spencer

1999-01-01

The environment in which bremsstrahlung and pair creation occurs can strongly affect cross sections for these processes. Because ultrarelativistic electromagnetic interactions involve very small longitudinal momentum transfers, the reactions occur gradually, spread over long distances. During this time, even relatively weak factors can accumulate enough to disrupt the interaction. In the Landau-Pomeranchuk-Migdal effect, multiple scattering reduces the bremsstrahlung and pair production cross section. This review will discuss this and a variety of other factors that can suppress bremsstrahlung and pair production, as well as related effects involving beamstrahlung and QCD processes. After surveying different theoretical approaches, experimental measurements will be covered. Recent accurate measurements by the SLAC E-146 Collaboration will be highlighted, along with several recent theoretical works relating to the experiment. (c) 1999 The American Physical Society

Multi-user distribution of polarization entangled photon pairs

Energy Technology Data Exchange (ETDEWEB)

Trapateau, J.; Orieux, A.; Diamanti, E.; Zaquine, I., E-mail: isabelle.zaquine@telecom-paristech.fr [LTCI, CNRS, Télécom ParisTech, Université Paris-Saclay, 75013 Paris (France); Ghalbouni, J. [Applied Physics Laboratory, Faculty of Sciences 2, Lebanese University, Campus Fanar, BP 90656 Jdeidet (Lebanon)

2015-10-14

We experimentally demonstrate multi-user distribution of polarization entanglement using commercial telecom wavelength division demultiplexers. The entangled photon pairs are generated from a broadband source based on spontaneous parametric down conversion in a periodically poled lithium niobate crystal using a double path setup employing a Michelson interferometer and active phase stabilisation. We test and compare demultiplexers based on various technologies and analyze the effect of their characteristics, such as losses and polarization dependence, on the quality of the distributed entanglement for three channel pairs of each demultiplexer. In all cases, we obtain a Bell inequality violation, whose value depends on the demultiplexer features. This demonstrates that entanglement can be distributed to at least three user pairs of a network from a single source. Additionally, we verify for the best demultiplexer that the violation is maintained when the pairs are distributed over a total channel attenuation corresponding to 20 km of optical fiber. These techniques are therefore suitable for resource-efficient practical implementations of entanglement-based quantum key distribution and other quantum communication network applications.

Pair Programming: Under What Conditions Is It Advantageous for Middle School Students?

Science.gov (United States)

Denner, Jill; Werner, Linda; Campe, Shannon; Ortiz, Eloy

2014-01-01

Pair programming is a strategy that grew out of industry and has shown promise for performance and retention in computer programming courses at universities and in industry. In this study, we examine whether pair programming is effective in K-12, what it is effective for, and how partners influence each other. We collected the data from 320 middle…

Pairing correlations. II. Microscopic analysis of odd-even mass staggering in nuclei

International Nuclear Information System (INIS)

Duguet, T.; Bonche, P.; Heenen, P.-H.; Meyer, J.

2002-01-01

The odd-even mass staggering in nuclei is analyzed in the context of self-consistent mean-field calculations, for spherical as well as for deformed nuclei. For these nuclei, the respective merits of the energy differences Δ (3) and Δ (5) to extract both the pairing gap and the time-reversal symmetry breaking effect at the same time are extensively discussed. The usual mass formula Δ (3) is shown to contain additional mean-field contributions when realistic pairing is used in the calculation. A simple tool is proposed in order to remove the time-reversal symmetry breaking effects from Δ (5) . Extended comparisons with the odd-even mass staggering obtained in the zero-pairing limit (schematic model and self-consistent calculations) show the nonperturbative contribution of pairing correlations on this observable

Pair production by a deep potential well

International Nuclear Information System (INIS)

Nikishov, A.I.

1987-01-01

Solutions are obtained for the Dirac and Klein-Gordon equations with a one-dimensional symmetric potential well, having a flat bottom and arbitrary depth, width and field strengths at the walls. Quasi-stationary solutions describing a pair production by the well and the inverse process are obtained. It is shown that if the pair production probability is small, it is expressed in terms of the pair production probability on one wall and the particle oscillation frequency in the well. If the well has a supercritical depth, the lower continuum contains positron resonance scattering states at energies close to the real part of the quasi-stationary level energy (Zeldovich's effect). The qualitative dependence of the positron penetration coefficient through the wall on its energy and the well depth is an evidence that the solution of the so called one-particle Dirac equation describes in fact a many-particle system with a charge of 0 or 1

Pair distribution function and structure factor of spherical particles

International Nuclear Information System (INIS)

Howell, Rafael C.; Proffen, Thomas; Conradson, Steven D.

2006-01-01

The availability of neutron spallation-source instruments that provide total scattering powder diffraction has led to an increased application of real-space structure analysis using the pair distribution function. Currently, the analytical treatment of finite size effects within pair distribution refinement procedures is limited. To that end, an envelope function is derived which transforms the pair distribution function of an infinite solid into that of a spherical particle with the same crystal structure. Distributions of particle sizes are then considered, and the associated envelope function is used to predict the particle size distribution of an experimental sample of gold nanoparticles from its pair distribution function alone. Finally, complementing the wealth of existing diffraction analysis, the peak broadening for the structure factor of spherical particles, expressed as a convolution derived from the envelope functions, is calculated exactly for all particle size distributions considered, and peak maxima, offsets, and asymmetries are discussed

Effect of single interstitial impurity in iron-based superconductors with sign-changed s-wave pairing symmetry

Energy Technology Data Exchange (ETDEWEB)

Yu, Xiang-Long, E-mail: xlyu@theory.issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Liu, Da-Yong; Quan, Ya-Min; Zheng, Xiao-Jun [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Zou, Liang-Jian, E-mail: zou@theory.issp.ac.cn [Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, P. O. Box 1129, Hefei 230031 (China); Department of Physics, University of Science and Technology of China, Hefei 230026 (China)

2015-12-15

Highlights: • Effects of single interstitial impurity are studied in iron-based superconductors. • Bound states within the superconducting gap can be induced. • The interstitial impurity can induce a π phase shift of pairing order parameter. • For strong magnetic scattering the bound-state peak can appear at the Fermi level. - Abstract: We employ the self-consistent Bogoliubov-de Gennes (BdG) formulation to investigate the effect of single interstitial nonmagnetic/magnetic impurity in iron-based superconductors with s ± -wave pairing symmetry. We find that both the nonmagnetic and magnetic impurities can induce bound states within the superconducting (SC) gap and a π phase shift of SC order parameter at the impurity site. However, different from the interstitial-nonmagnetic-impurity case characterized by two symmetric peaks with respect to zero energy, the interstitial magnetic one only induces single bound-state peak. In the strong scattering regime this peak can appear at the Fermi level, which has been observed in the recent scanning tunneling microscope (STM) experiment of Fe(Te,Se) superconductor with interstitial Fe impurities (Yin et al. 2015 [44]). This novel single in-gap peak feature also distinguishes the interstitial case from the substitutional one with two peaks. These results provide important information for comparing the different impurity effects in the iron-based superconductors.

Damage Mechanism in Counter Pairs Caused by Bionic Non-smoothed Surface

Directory of Open Access Journals (Sweden)

ZHANG Zhan-hui

2016-08-01

Full Text Available Four biomimetic non-smoothed surface specimens with different shapes were prepared by laser processing. Tests were conducted on MMU-5G wear and abrasion test machine to study the influencing rule of non-smoothed surfaces on counter pairs. The results show that the mass loss of the friction pair matching with the non-smoothed units is much greater than the ones matching with the smooth specimens. The pairs matching with different non-smoothed units suffer differently. The non-smoothed surface protruding zone exerts micro cutting on counter pairs. The striation causes the greatest mass loss of the pairs than the other non-smoothed units, which almost doubles the damage of the grid ones suffering the least. The difference in pairs damage is attributed to the different mechanism of undertaking the load in the process of wear. The damage can be alleviated effectively by changing the shapes of the units without increasing or decreasing the area ratio of the non-smoothed units.

Affine pairings on ARM

NARCIS (Netherlands)

Acar, T.; Lauter, K.; Naehrig, M.; Shumow, D.

2011-01-01

Pairings on elliptic curves are being used in an increasing number of cryptographic applications on many different devices and platforms, but few performance numbers for cryptographic pairings have been reported on embedded and mobile devices. In this paper we give performance numbers for affine and

Solutions of nuclear pairing

International Nuclear Information System (INIS)

Balantekin, A. B.; Pehlivan, Y.

2007-01-01

We give the exact solution of orbit dependent nuclear pairing problem between two nondegenerate energy levels using the Bethe ansatz technique. Our solution reduces to previously solved cases in the appropriate limits including Richardson's treatment of reduced pairing in terms of rational Gaudin algebra operators

Single, but not multiple pairings of sucrose and corticosterone enhance memory for sucrose drinking and amplify remote reward relativity effects

NARCIS (Netherlands)

Pecoraro, Norman; Gomez, Francisca; La Fleur, Susanne; Roy, Monica; Dallman, Mary F.

2005-01-01

This study tested whether pre-training pairings of ingestion of a 32% sucrose solution and injection(s) of corticosterone (B) would enhance later ingestion in the absence of B, and whether these effects would carry over into later contrast-like effects when animals were subsequently shifted to 4%

Impact of Paired Tutoring and Mentoring.

Science.gov (United States)

Bruce, Jennifer E.; Trammell, Jack

2003-01-01

Discusses a study that examines the effects of paired tutoring and mentoring on academic achievement of college freshmen in a probationary program. Results show that students with mentoring and tutoring services by the same person show greater academic gains as measured by compliance and academic achievement than do those students who were…

Paired Hall states

International Nuclear Information System (INIS)

Greiter, M.

1992-01-01

This dissertation contains a collection of individual articles on various topics. Their significance in the corresponding field as well as connections between them are emphasized in a general and comprehensive introduction. In the first article, the author explores the consequences for macroscopic effective Lagrangians of assuming that the momentum density is proportional to the flow of conserved current. The universal corrections obtained for the macroscopic Lagrangian of a superconductor describe the London Hall effect, and provide a fully consistent derivation of it. In the second article, a heuristic principle is proposed for quantized Hall states: the existence and incompressibility of fractionally quantized Hall states is explained by an argument based on an adiabatic localization of magnetic flux, the process of trading uniform flux for an equal amount of fictitious flux attached to the particles. This principle is exactly implemented in the third article. For a certain class of model Hamiltonians, the author obtains Laughlin's Jastrow type wave functions explicitly from a filled Landau level, by smooth extrapolation in quantum statistics. The generalization of this analysis to the torus geometry shows that theorems restricting the possibilities of quantum statistics on closed surfaces are circumvented in the presence of a magnetic field. In the last article, the existence is proposed of a novel incompressible quantum liquid, a paired Hall state, at a half filled Landau level. This state arises adiabatically from free fermions in zero magnetic field, and reduces to a state previously proposed by Halperin in the limit of tightly bound pairs. It supports unusual excitations, including neutral fermions and charge e/4 anyons with statistical parameter θ = π/8

Synergy between pair coupled cluster doubles and pair density functional theory

Energy Technology Data Exchange (ETDEWEB)

Garza, Alejandro J.; Bulik, Ireneusz W. [Department of Chemistry, Rice University, Houston, Texas 77251-1892 (United States); Henderson, Thomas M. [Department of Chemistry and Department of Physics and Astronomy, Rice University, Houston, Texas 77251-1892 (United States); Scuseria, Gustavo E. [Department of Chemistry and Department of Physics and Astronomy, Rice University, Houston, Texas 77251-1892 (United States); Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)

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.

Radiation-mediated Shocks in Gamma-Ray Bursts: Pair Creation

Science.gov (United States)

Lundman, Christoffer; Beloborodov, Andrei M.; Vurm, Indrek

2018-05-01

Relativistic sub-photospheric shocks are a possible mechanism for producing prompt gamma-ray burst (GRB) emission. Such shocks are mediated by scattering of radiation. We introduce a time-dependent, special relativistic code which dynamically couples Monte Carlo radiative transfer to the flow hydrodynamics. The code also self-consistently follows electron–positron pair production in photon–photon collisions. We use the code to simulate shocks with properties relevant to GRBs. We focus on plane-parallel solutions, which are accurate deep below the photosphere. The shock generates a power-law photon spectrum through the first-order Fermi mechanism, extending upward from the typical upstream photon energy. Strong (high Mach number) shocks produce rising νF ν spectra. We observe that in non-relativistic shocks the spectrum extends to {E}\\max ∼ {m}e{v}2, where v is the speed difference between the upstream and downstream. In relativistic shocks the spectrum extends to energies E> 0.1 {m}e{c}2 where its slope softens due to Klein–Nishina effects. Shocks with Lorentz factors γ > 1.5 are prolific producers of electron–positron pairs, yielding hundreds of pairs per proton. The main effect of pairs is to reduce the shock width by a factor of ∼ {Z}+/- -1. Most pairs annihilate far downstream of the shock, and the radiation spectrum relaxes to a Wien distribution, reaching equilibrium with the plasma at a temperature determined by the shock jump conditions and the photon number per proton. We discuss the implications of our results for observations of radiation generated by sub-photospheric shocks.

RELAXATION OF BLAZAR-INDUCED PAIR BEAMS IN COSMIC VOIDS

Energy Technology Data Exchange (ETDEWEB)

Miniati, Francesco [Physics Department, Wolfgang-Pauli-Strasse 27, ETH-Zuerich, CH-8093 Zuerich (Switzerland); Elyiv, Andrii, E-mail: fm@phys.ethz.ch [Institut d' Astrophysique et de Geophysique, Universite de Liege, B-4000 Liege (Belgium)

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.

Secure pairing with biometrics

NARCIS (Netherlands)

Buhan, I.R.; Boom, B.J.; Doumen, J.M.; Hartel, Pieter H.; Veldhuis, Raymond N.J.

Secure pairing enables two devices that share no prior context with each other to agree upon a security association, which they can use to protect their subsequent communication. Secure pairing offers guarantees of the association partner identity and it should be resistant to eavesdropping and to a

Computational studies of a cut-wire pair and combined metamaterials

International Nuclear Information System (INIS)

Nguyen, Thanh Tung; Lievens, Peter; Lee, Young Pak; Vu, Dinh Lam

2011-01-01

The transfer-matrix method and finite-integration simulations show how the transmission properties of combined metamaterials, which consist of metallic cut-wire pairs and continuous wires, are affected by geometric parameters. The corresponding effective permittivity and permeability are retrieved from the complex scattering parameters using the standard retrieval procedure. The electromagnetic properties of the cut-wire pair as well as the left-handed behavior of the combined structure are understood by the effective medium theory. In addition, the dimensional dependence of transmission properties, the shapes of cut-wire pairs and continuous wire, and the impact of dielectric spacer are both examined. Finally, by expanding the results of previous research (Koschny et al 2003 Phys. Rev. Lett. 93 016608), we generalize the transmission picture of combined structures in terms of the correlation between electric and magnetic responses. (review)

Property (RD) for Hecke Pairs

International Nuclear Information System (INIS)

Shirbisheh, Vahid

2012-01-01

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.

Investigations into nuclear pairing

International Nuclear Information System (INIS)

Clark, R.M.

2006-01-01

This paper is divided in two main sections focusing on different aspects of collective nuclear behavior. In the first section, solutions are considered for the collective pairing Hamiltonian. In particular, an approximate solution at the critical point of the pairing transition from harmonic vibration (normal nuclear behavior) to deformed rotation (superconducting behavior) in gauge space is found by analytic solution of the Hamiltonian. The eigenvalues are expressed in terms of the zeros of Bessel functions of integer order. The results are compared to the pairing bands based on the Pb isotopes. The second section focuses on the experimental search for the Giant Pairing Vibration (GPV) in nuclei. After briefly describing the origin of the GPV, and the reasons that the state has remained unidentified, a novel idea for populating this state is presented. A recent experiment has been performed using the LIBERACE+STARS detector system at the 88-Inch Cyclotron of LBNL to test the idea. (Author)

W-pair production near threshold in unstable particle effective theory

Energy Technology Data Exchange (ETDEWEB)

Falgari, Pietro

2008-11-07

In this thesis we present a dedicated study of the four-fermion production process e{sup +}e{sup -}{yields}{mu}{sup -} anti {nu}{sub {mu}}u anti dX near the W-pair production threshold, in view of its importance for a precise determination of the W-boson mass at the ILC. The calculation is performed in the framework of unstable-particle effective theory, which allows for a gauge-invariant inclusion of instability effects, and for a systematic approximation of the full cross section with an expansion in the coupling constants, the ratio {gamma}{sub W}/M{sub W}, and the non-relativistic velocity v of the W boson. The effective-theory result, computed to next-to-leading order in the expansion parameters {gamma}{sub W}/M{sub W}{proportional_to}{alpha}{sub ew}{proportional_to}v{sup 2}, is compared to the full numerical next-to-leading order calculation of the four-fermion production cross section, and agreement to better than 0.5% is found in the region of validity of the effective theory. Furthermore, we estimate the contributions of missing higher-order corrections to the four-fermion process, and how they translate into an error on the W-boson mass determination. We find that the dominant theoretical uncertainty on MW is currently due to an incomplete treatment of initial-state radiation, while the remaining combined uncertainty of the two NLO calculations translates into {delta}M{sub W}{approx} 5 MeV. The latter error is removed by an explicit computation of the dominant missing terms, which originate from the expansion in v of next-to-next-to-leading order Standard Model diagrams. The effect of resummation of logarithmically-enhanced terms is also investigated, but found to be negligible. (orig.)

Effect of μe universality violation in muon pair production on colliding electron-positron beams

International Nuclear Information System (INIS)

Guliev, N.A.; Dzhafarov, I.G.; Mekhtiev, B.I.

1981-01-01

The muonic pair production in colliding electron-positron beams is treated assuming the electron and muon weak interaction constants to be different. General formulae for the differential and total cross sections applicable at arbitrary energies of the colliding beams are obtained taking simultaneously into account arbitrary polarizations of the incident particles and longitudinal polarization of the muon (μ - ). It is shown that study of some polarization characteristics of a given reaction allows to distinguish possible weak interaction μe universality breaking effects. The revealing effects are analysed in the framework of unified gauge SU(2)xU(1) models, of weak and electromagnetic interactions [ru

Problems of quantum electrodynamics with external field creating pairs

International Nuclear Information System (INIS)

Fradkin, E.S.; Gitman, D.M.

1979-11-01

This paper is a preliminary version of a review of the results obtained by the authors and their collaborators which mainly concern problems of quantum electrodynamics with the pair-creating external field. In this paper the Furry picture is constructed for quantum electrodynamics with the pair-creating external field. It is shown, that various Green functions in the external field arise in the theory in a natural way. Special features of usage of the unitarity conditions for calculating the total probabilities of transitions are discussed. Perturbation theory for determining the mean electromagnetic field is constructed. Effective Lagrangians for pair-creating fields are built. One of the possible ways to introduce external field in quantum electrodynamics is considered. All the Green functions arising in the theory suggested are calculated for a constant field and a plane wave field. For the case of the electric field the total probability of creation of pairs from the vacuum accompanied by the photon irradiation and the total probability of transition from a single-electron state accompanied by the photon irradiation and creation of pairs are obtained by using the formulated rules for calculating the total probabilities of transitions. (author)

The pairing theory of polarons in real- and impulse spaces

International Nuclear Information System (INIS)

Dzhumanov, S.; Abboudy, S.; Baratov, A.A.

1995-07-01

A consistent pairing theory of carriers in real- and impulse spaces is developed. The pairing of different free (F), delocalized (D) and self-trapped (S) carriers in real-space, leading to the formation of various bipolaronic states are considered within the continuum model and adiabatic approximation taking into account the combined effect of the short- and long-range components of electron-lattice interaction with and without electron correlation. The formation possibility of D- and S-bipolarons as a function of ε ∞ /ε 0 are shown. The pairing scenarios of carriers in k-space leading to the formation of different bipolarons (including also Cooper pairs dynamic bipolarons) are considered within the generalized BCS-like model taking into account the combined phonon and polaron-bag mediated processes. It is shown that the pure BCS pairing picture is the particular case of the general BCS-like one. The possible relevance of the obtained results to high-T c superconductors is discussed in details in the framework of a novel two-stage Fermi-Bose-liquid scenarios of superconductivity which is caused by single particle and pair condensation of an attracting bipolarons. (author). 51 refs, 6 figs

On magnon mediated Cooper pair formation in ferromagnetic superconductors

Directory of Open Access Journals (Sweden)

Rakesh Kar

2014-08-01

Full Text Available Identification of pairing mechanism leading to ferromagnetic superconductivity is one of the most challenging issues in condensed matter physics. Although different models have been proposed to explain this phenomenon, a quantitative understanding about this pairing is yet to be achieved. Using the localized-itinerant model, we find that in ferromagnetic superconducting materials both triplet pairing and singlet pairing of electrons are possible through magnon exchange depending upon whether the Debye cut off frequency of magnons is greater or lesser than the Hund's coupling (J multiplied by average spin (S per site. Taking into account the repulsive interaction due to the existence of paramagnons, we also find an expression for effective interaction potential between a pair of electrons with opposite spins. We apply the developed formalism in case of UGe2 and URhGe. The condition of singlet pairing is found to be fulfilled in these cases, as was previously envisaged by Suhl [Suhl, Phys. Rev. Lett. 87, 167007 (2001]. We compute the critical temperatures of URhGe at ambient pressure and of UGe2 under different pressures for the first time through BCS equation. Thus, this work outlines a very simple way to evaluate critical temperature in case of a superconducting system. A close match with the available experimental results strongly supports our theoretical treatment.

A natively paired antibody library yields drug leads with higher sensitivity and specificity than a randomly paired antibody library.

Science.gov (United States)

Adler, Adam S; Bedinger, Daniel; Adams, Matthew S; Asensio, Michael A; Edgar, Robert C; Leong, Renee; Leong, Jackson; Mizrahi, Rena A; Spindler, Matthew J; Bandi, Srinivasa Rao; Huang, Haichun; Tawde, Pallavi; Brams, Peter; Johnson, David S

2018-04-01

Deep sequencing and single-chain variable fragment (scFv) yeast display methods are becoming more popular for discovery of therapeutic antibody candidates in mouse B cell repertoires. In this study, we compare a deep sequencing and scFv display method that retains native heavy and light chain pairing with a related method that randomly pairs heavy and light chain. We performed the studies in a humanized mouse, using interleukin 21 receptor (IL-21R) as a test immunogen. We identified 44 high-affinity binder scFv with the native pairing method and 100 high-affinity binder scFv with the random pairing method. 30% of the natively paired scFv binders were also discovered with the randomly paired method, and 13% of the randomly paired binders were also discovered with the natively paired method. Additionally, 33% of the scFv binders discovered only in the randomly paired library were initially present in the natively paired pre-sort library. Thus, a significant proportion of "randomly paired" scFv were actually natively paired. We synthesized and produced 46 of the candidates as full-length antibodies and subjected them to a panel of binding assays to characterize their therapeutic potential. 87% of the antibodies were verified as binding IL-21R by at least one assay. We found that antibodies with native light chains were more likely to bind IL-21R than antibodies with non-native light chains, suggesting a higher false positive rate for antibodies from the randomly paired library. Additionally, the randomly paired method failed to identify nearly half of the true natively paired binders, suggesting a higher false negative rate. We conclude that natively paired libraries have critical advantages in sensitivity and specificity for antibody discovery programs.

A multilevel model of organizational health culture and the effectiveness of health promotion.

Science.gov (United States)

Lin, Yea-Wen; Lin, Yueh-Ysen

2014-01-01

Organizational health culture is a health-oriented core characteristic of the organization that is shared by all members. It is effective in regulating health-related behavior for employees and could therefore influence the effectiveness of health promotion efforts among organizations and employees. This study applied a multilevel analysis to verify the effects of organizational health culture on the organizational and individual effectiveness of health promotion. At the organizational level, we investigated the effect of organizational health culture on the organizational effectiveness of health promotion. At the individual level, we adopted a cross-level analysis to determine if organizational health culture affects employee effectiveness through the mediating effect of employee health behavior. The study setting consisted of the workplaces of various enterprises. We selected 54 enterprises in Taiwan and surveyed 20 full-time employees from each organization, for a total sample of 1011 employees. We developed the Organizational Health Culture Scale to measure employee perceptions and aggregated the individual data to formulate organization-level data. Organizational effectiveness of health promotion included four dimensions: planning effectiveness, production, outcome, and quality, which were measured by scale or objective indicators. The Health Promotion Lifestyle Scale was adopted for the measurement of health behavior. Employee effectiveness was measured subjectively in three dimensions: self-evaluated performance, altruism, and happiness. Following the calculation of descriptive statistics, hierarchical linear modeling (HLM) was used to test the multilevel hypotheses. Organizational health culture had a significant effect on the planning effectiveness (β = .356, p production (β = .359, p promotion. In addition, results of cross-level moderating effect analysis by HLM demonstrated that the effects of organizational health culture on three dimensions of

Interplay of quasiparticle-vibration coupling and pairing correlations on β-decay half-lives

Science.gov (United States)

Niu, Y. F.; Niu, Z. M.; Colò, G.; Vigezzi, E.

2018-05-01

The nuclear β-decay half-lives of Ni and Sn isotopes, around the closed shell nuclei 78Ni and 132Sn, are investigated by computing the distribution of the Gamow-Teller strength using the Quasiparticle Random Phase Approximation (QRPA) with quasiparticle-vibration coupling (QPVC), based on ground-state properties obtained by Hartree-Fock-Bogoliubov (HFB) calculations. We employ the effective interaction SkM* and a zero-range effective pairing force. The half-lives are strongly reduced by including the QPVC. We study in detail the effects of isovector (IV) and isoscalar (IS) pairing. Increasing the IV strength tends to increase the lifetime for nuclei in the proximity of, but lighter than, the closed-shell ones in QRPA calculations, while the effect is significantly reduced by taking into account the QPVC. On the contrary, the IS pairing mainly plays a role for nuclei after the shell closure. Increasing its strength decreases the half-lives, and the effect at QRPA and QRPA+QPVC level is comparable. The effect of IS pairing is particularly pronounced in the case of the Sn isotopes, where it turns out to be instrumental to obtain good agreement with experimental data.

Instability of vortex pair leapfrogging

DEFF Research Database (Denmark)

Tophøj, Laust; Aref, Hassan

2013-01-01

Leapfrogging is a periodic solution of the four-vortex problem with two positive and two negative point vortices all of the same absolute circulation arranged as co-axial vortex pairs. The set of co-axial motions can be parameterized by the ratio 0 vortex pair sizes at the time when one...... pair passes through the other. Leapfrogging occurs for α > σ2, where is the silver ratio. The motion is known in full analytical detail since the 1877 thesis of Gröbli and a well known 1894 paper by Love. Acheson ["Instability of vortex leapfrogging," Eur. J. Phys.21, 269-273 (2000...... pairs fly off to infinity, and a "walkabout" mode, where the vortices depart from leapfrogging but still remain within a finite distance of one another. We show numerically that this transition is more gradual, a result that we relate to earlier investigations of chaotic scattering of vortex pairs [L...

Pairing induced superconductivity in holography

Science.gov (United States)

Bagrov, Andrey; Meszena, Balazs; Schalm, Koenraad

2014-09-01

We study pairing induced superconductivity in large N strongly coupled systems at finite density using holography. In the weakly coupled dual gravitational theory the mechanism is conventional BCS theory. An IR hard wall cut-off is included to ensure that we can controllably address the dynamics of a single confined Fermi surface. We address in detail the interplay between the scalar order parameter field and fermion pairing. Adding an explicitly dynamical scalar operator with the same quantum numbers as the fermion-pair, the theory experiences a BCS/BEC crossover controlled by the relative scaling dimensions. We find the novel result that this BCS/BEC crossover exposes resonances in the canonical expectation value of the scalar operator. This occurs not only when the scaling dimension is degenerate with the Cooper pair, but also with that of higher derivative paired operators. We speculate that a proper definition of the order parameter which takes mixing with these operators into account stays finite nevertheless.

Let's stay together? Intrinsic and extrinsic factors involved in pair bond dissolution in a recolonizing wolf population.

Science.gov (United States)

Milleret, Cyril; Wabakken, Petter; Liberg, Olof; Åkesson, Mikael; Flagstad, Øystein; Andreassen, Harry Peter; Sand, Håkan

2017-01-01

For socially monogamous species, breeder bond dissolution has important consequences for population dynamics, but the extent to which extrinsic or intrinsic population factors causes pair dissolution remain poorly understood, especially among carnivores. Using an extensive life-history data set, a survival analysis and competing risks framework, we examined the fate of 153 different wolf (Canis lupus) pairs in the recolonizing Scandinavian wolf population, during 14 winters of snow tracking and DNA monitoring. Wolf pair dissolution was generally linked to a mortality event and was strongly affected by extrinsic (i.e. anthropogenic) causes. No divorce was observed, and among the pair dissolution where causes have been identified, death of one or both wolves was always involved. Median time from pair formation to pair dissolution was three consecutive winters (i.e. approximately 2 years). Pair dissolution was mostly human-related, primarily caused by legal control actions (36·7%), verified poaching (9·2%) and traffic-related causes (2·1%). Intrinsic factors, such as disease and age, accounted for only 7·7% of pair dissolutions. The remaining 44·3% of dissolution events were from unknown causes, but we argue that a large portion could be explained by an additional source of human-caused mortality, cryptic poaching. Extrinsic population factors, such as variables describing the geographical location of the pair, had a stronger effect on risk of pair dissolution compared to anthropogenic landscape characteristics. Population intrinsic factors, such as the inbreeding coefficient of the male pair member, had a negative effect on pair bond duration. The mechanism behind this result remains unknown, but might be explained by lower survival of inbred males or more complex inbreeding effects mediated by behaviour. Our study provides quantitative estimates of breeder bond duration in a social carnivore and highlights the effect of extrinsic (i.e. anthropogenic) and

Training IBM Watson using Automatically Generated Question-Answer Pairs

OpenAIRE

Lee, Jangho; Kim, Gyuwan; Yoo, Jaeyoon; Jung, Changwoo; Kim, Minseok; Yoon, Sungroh

2016-01-01

IBM Watson is a cognitive computing system capable of question answering in natural languages. It is believed that IBM Watson can understand large corpora and answer relevant questions more effectively than any other question-answering system currently available. To unleash the full power of Watson, however, we need to train its instance with a large number of well-prepared question-answer pairs. Obviously, manually generating such pairs in a large quantity is prohibitively time consuming and...

Structural context effects in the oxidation of 8-oxo-7,8-dihydro-2'-deoxyguanosine to hydantoin products: electrostatics, base stacking, and base pairing.

Science.gov (United States)

Fleming, Aaron M; Muller, James G; Dlouhy, Adrienne C; Burrows, Cynthia J

2012-09-12

8-Oxo-7,8-dihydroguanine (OG) is the most common base damage found in cells, where it resides in many structural contexts, including the nucleotide pool, single-stranded DNA at transcription forks and replication bubbles, and duplex DNA base-paired with either adenine (A) or cytosine (C). OG is prone to further oxidation to the highly mutagenic hydantoin products spiroiminodihydantoin (Sp) and 5-guanidinohydantoin (Gh) in a sharply pH-dependent fashion within nucleosides. In the present work, studies were conducted to determine how the structural context affects OG oxidation to the hydantoins. These studies revealed a trend in which the Sp yield was greatest in unencumbered contexts, such as nucleosides, while the Gh yield increased in oligodeoxynucleotide (ODN) contexts or at reduced pH. Oxidation of oligomers containing hydrogen-bond modulators (2,6-diaminopurine, N(4)-ethylcytidine) or alteration of the reaction conditions (pH, temperature, and salt) identify base stacking, electrostatics, and base pairing as the drivers of the key intermediate 5-hydroxy-8-oxo-7,8-dihydroguanine (5-HO-OG) partitioning along the two hydantoin pathways, allowing us to propose a mechanism for the observed base-pairing effects. Moreover, these structural effects cause an increase in the effective pK(a) of 5-HO-OG, following an increasing trend from 5.7 in nucleosides to 7.7 in a duplex bearing an OG·C base pair, which supports the context-dependent product yields. The high yield of Gh in ODNs underscores the importance of further study on this lesion. The structural context of OG also determined its relative reactivity toward oxidation, for which the OG·A base pair is ~2.5-fold more reactive than an OG·C base pair, and with the weak one-electron oxidant ferricyanide, the OG nucleoside reactivity is >6000-fold greater than that of OG·C in a duplex, leading to the conclusion that OG in the nucleoside pool should act as a protective agent for OG in the genome.

[Paired kidneys in transplant].

Science.gov (United States)

Regueiro López, Juan C; Leva Vallejo, Manuel; Prieto Castro, Rafael; Anglada Curado, Francisco; Vela Jiménez, Francisco; Ruiz García, Jesús

2009-02-01

Many factors affect the graft and patient survival on the renal transplant outcome. These factors depend so much of the recipient and donor. We accomplished a study trying to circumvent factors that depend on the donor. We checked the paired kidneys originating of a same donor cadaver. We examined the risk factors in the evolution and follow-up in 278 couples of kidney transplant. We describe their differences, significance, the graft and patient survival, their functionality in 3 and 5 years and the risk factors implicated in their function. We study immunogenic and no immunogenic variables, trying to explain the inferior results in the grafts that are established secondly. We regroup the paired kidneys in those that they did not show paired initial function within the same couple. The results yield a discreet deterioration in the graft and patient survival for second group establish, superior creatinina concentration, without obtaining statistical significance. The Cox regression study establishes the early rejection (inferior to three months) and DR incompatibility values like risk factors. This model of paired kidneys would be able to get close to best-suited form for risk factors analysis in kidney transplant from cadaver donors, if more patients examine themselves in the same way. The paired kidneys originating from the same donor do not show the same function in spite of sharing the same conditions of the donor and perioperative management.

Pneumoproteins as a lung-specific biomarker of alveolar permeability in conventional on-pump coronary artery bypass graft surgery vs mini-extracorporeal circuit - A pilot study

NARCIS (Netherlands)

van Boven, WJP; Gerritsen, WBM; Zanen, P; Grutters, JC; van Dongen, HPA; Bernard, A; Aarts, LPHJ

Background: Despite improvements of the heart-lung machine (HLM), oxidative stress and subsequent damage to the alveolar capillary membrane still occur after conventional on-pump coronary artery bypass graft (CCABG) surgery. In an attempt to further improve the conventional HLM, a

A Hierarchical Linear Model for Estimating Gender-Based Earnings Differentials.

Science.gov (United States)

Haberfield, Yitchak; Semyonov, Moshe; Addi, Audrey

1998-01-01

Estimates of gender earnings inequality in data from 116,431 Jewish workers were compared using a hierarchical linear model (HLM) and ordinary least squares model. The HLM allows estimation of the extent to which earnings inequality depends on occupational characteristics. (SK)

Alignments of multi-quasiparticle bands and seniority-dependent reduced pairing

International Nuclear Information System (INIS)

Dracoulis, G.D.

1994-09-01

Pairing correlations in multi-quasiparticle states in deformed nuclei are expected to be reduced because of blocking. New intrinsic states and their associated rotational bands have been identified allowing comparisons to be made as a function of seniority and between nuclei. The possible effects of the reduced pairing on the collective rotation, and its manifestation in terms of alignment, are discussed. 13 refs., 2 figs

Conditions for formation of electron pairs in a metal

Energy Technology Data Exchange (ETDEWEB)

Shekhtman, A.Z., E-mail: shekhtmanalexander@gmail.com

2015-04-15

Highlights: • A new approach has been developed for consideration of electron pairing in metals. • Binding energy of a single pair induced by electron-phonon interaction is very small. • A new mechanism for electron pairing in metals has been considered. • Conditions for feasibility of the mechanism give conditions for electron pairing. • The mechanism gives wide opportunities to study new conditions for electron pairing. - Abstract: In an isotropic model of the electron system of metal that is presented by the Fröhlich’s initial Hamiltonian, in the approximation of a weak electron–phonon interaction at T = 0, first time, we show that the ground state of the system is the state with pairing correlations of electrons (the pair correlations of occupied electron states). In contrast to the BCS approach, the initial point in our approach is not electron pairing but is the maximum reduction of the energy of the considered system due to virtual processes of the electron–phonon interaction and to the exchange effect for the indirect electron–electron interaction (which is induced by certain phonon modes separately from others). In contrast to the BCS approach, we take into account the portion of the energy of the electron system that is connected with the above exchange effect. In the BCS approach, the corresponding portion is missed, and its role is prescribed to the portion that does not relate to the electron pairing. We show that expectation values of the above Hamiltonian for different wave functions for two interacting electrons above the Fermi sea of the non-interacting system (with interaction between the electrons that is induced by different phonon modes separately from others) are minimum for a certain structure of these functions and simultaneously for phonon modes that can induce the transitions of the interacting electrons between electron states in which they are (without violation of the Pauli exclusion principle and at everything else

Taste avoidance induced by wheel running: effects of backward pairings and robustness of conditioned taste aversion.

Science.gov (United States)

Salvy, Sarah-Jeanne; Pierce, W David; Heth, Donald C; Russell, James C

2004-09-15

Rats repeatedly exposed to a distinctive novel solution (conditioned stimulus, CS) followed by the opportunity to run in a wheel subsequently drink less of this solution. Investigations on this phenomenon indicate that wheel running is an effective unconditioned stimulus (US) for establishing conditioned taste aversion (CTA) when using a forward conditioning procedure (i.e., the US-wheel running follows the CS-taste). However, other studies show that wheel running produces reliable preference for a distinctive place when pairings are backward (i.e., the CS-location follows the US-wheel running). One possibility to account for these results is that rewarding aftereffects of wheel running conditioned preference to the CS. The main objective of the present study was to assess the effects of backward conditioning using wheel running as the US and a distinctive taste as the CS. In a between-groups design, two experimental groups [i.e., forward (FC) and backward conditioning (BC)] and two control groups [CS-taste alone (TA) and CS-US unpaired (UNP)] were compared. Results from this experiment indicated that there is less suppression of drinking when a CS-taste followed a bout of wheel running. In fact, rats in the BC group drank more of the paired solution than all the other groups.

Preferred and avoided codon pairs in three domains of life

Directory of Open Access Journals (Sweden)

Tenson Tanel

2008-10-01

Full Text Available Abstract Background Alternative synonymous codons are not used with equal frequencies. In addition, the contexts of codons – neighboring nucleotides and neighboring codons – can have certain patterns. The codon context can influence both translational accuracy and elongation rates. However, it is not known how strong or conserved the codon context preferences in different organisms are. We analyzed 138 organisms (bacteria, archaea and eukaryotes to find conserved patterns of codon pairs. Results After removing the effects of single codon usage and dipeptide biases we discovered a set of neighboring codons for which avoidances or preferences were conserved in all three domains of life. Such biased codon pairs could be divided into subtypes on the basis of the nucleotide patterns that influence the bias. The most frequently avoided type of codon pair was nnUAnn. We discovered that 95.7% of avoided nnUAnn type patterns contain out-frame UAA or UAG triplets on the sense and/or antisense strand. On average, nnUAnn codon pairs are more frequently avoided in ORFeomes than in genomes. Thus we assume that translational selection plays a major role in the avoidance of these codon pairs. Among the preferred codon pairs, nnGCnn was the major type. Conclusion Translational selection shapes codon pair usage in protein coding sequences by rules that are common to all three domains of life. The most frequently avoided codon pairs contain the patterns nnUAnn, nnGGnn, nnGnnC, nnCGCn, GUCCnn, CUCCnn, nnCnnA or UUCGnn. The most frequently preferred codon pairs contain the patterns nnGCnn, nnCAnn or nnUnCn.

Hidden in Plain Sight: Subtle Effects of the 8-Oxoguanine Lesion on the Structure, Dynamics, and Thermodynamics of a 15-Base-Pair Oligodeoxynucleotide Duplex†

Science.gov (United States)

Crenshaw, Charisse M.; Wade, Jacqueline E.; Arthanari, Haribabu; Frueh, Dominique; Lane, Benjamin F.; Núñez, Megan E.

2011-01-01

The base lesion 8-oxoguanine is formed readily by oxidation of DNA, potentially leading to G→T transversion mutations. Despite the apparent similarity of 8-oxoguanine-cytosine base pairs to normal guanine-cytosine base pairs, cellular base excision repair systems effectively recognize the lesion base. Here we apply several techniques to examine a single 8-oxoguanine lesion at the center of a nonpalindromic 15-mer duplex oligonucleotide in an effort to determine what, if anything, distinguishes an 8-oxoguanine-cytosine base pair from a normal base pair. The lesion duplex is globally almost indistinguishable from the unmodified parent duplex using CD spectroscopy and UV melting thermodynamics. The DNA mismatch-detecting photocleavage agent Rh(bpy)2chrysi3+ cleaves only weakly and nonspecifically, revealing that the 8oxoG-C pair is locally stable at the level of the individual base pairs. NMR spectra are also consistent with a well-conserved B-form duplex structure. In the 2D NOESY spectra, base-sugar and imino-imino crosspeaks are strikingly similar between parent and lesion duplexes. Changes in chemical shift due to the 8oxoG lesion are localized to its complementary cytosine and to the 2–3 base pairs immediately flanking the lesion on the lesion strand. Residues further removed from the lesion are shown to be unperturbed by its presence. Notably, imino exchange experiments indicate that the 8-oxoguanine-cytosine pair is strong and stable, with an apparent equilibrium constant for opening equal to that of other internal guanine-cytosine base pairs, on the order of 10−6. This collection of experiments shows that the 8-oxoguanine-cytosine base pair is incredibly stable and similar to the native pair. PMID:21902242

Splitting efficiency and interference effects in a Cooper pair splitter based on a triple quantum dot with ferromagnetic contacts

Science.gov (United States)

Bocian, Kacper; Rudziński, Wojciech; Weymann, Ireneusz

2018-05-01

We theoretically study the spin-resolved subgap transport properties of a Cooper pair splitter based on a triple quantum dot attached to superconducting and ferromagnetic leads. Using the Keldysh Green's function formalism, we analyze the dependence of the Andreev conductance, Cooper pair splitting efficiency, and tunnel magnetoresistance on the gate and bias voltages applied to the system. We show that the system's transport properties are strongly affected by spin dependence of tunneling processes and quantum interference between different local and nonlocal Andreev reflections. We also study the effects of finite hopping between the side quantum dots on the Andreev current. This allows for identifying the optimal conditions for enhancing the Cooper pair splitting efficiency of the device. We find that the splitting efficiency exhibits a nonmonotonic dependence on the degree of spin polarization of the leads and the magnitude and type of hopping between the dots. An almost perfect splitting efficiency is predicted in the nonlinear response regime when the energies of the side quantum dots are tuned to the energies of the corresponding Andreev bound states. In addition, we analyzed features of the tunnel magnetoresistance (TMR) for a wide range of the gate and bias voltages, as well as for different model parameters, finding the corresponding sign changes of the TMR in certain transport regimes. The mechanisms leading to these effects are thoroughly discussed.

Higgs boson pair production: Top quark mass effects at NLO and NNLO

Directory of Open Access Journals (Sweden)

Jonathan Grigo

2015-11-01

Full Text Available We compute next-to-next-to-leading order QCD corrections to the gluon-induced production cross section of Higgs boson pairs in the large top quark mass limit using the soft-virtual approximation. In the limit of infinitely-heavy top quark we confirm the results in the literature. We add two more expansion terms in the inverse top quark mass to the Mt→∞ result. Since the 1/Mt expansion converges poorly, we try to improve on it by factorizing the exact leading order cross section. We discuss two ways of doing that and conclude that the finite top quark mass effects shift the cross section at most by about 10% at next-to-leading order and by about 5% at next-to-next-to-leading order.

Molecular Dynamics study of the effects of non-stoichiometry and oxygen Frenkel pairs on the thermal conductivity of uranium dioxide

International Nuclear Information System (INIS)

Nichenko, Sergii; Staicu, Dragos

2013-01-01

In the present work, calculations of the thermal conductivity of UO 2 were carried out applying classical Molecular Dynamics for the isothermal-isobaric (NPT) statistical ensemble, using the Green–Kubo approach. The thermal conductivity calculated for perfect stoichiometric UO 2 is in good agreement with the literature data over the temperature range corresponding to heat transfer by phonons (up to 1700 K). The effect of non-stoichiometry on the thermal conductivity was calculated taking into account the presence of polarons. It was found that for the same value of the stoichiometry deviation, the effect of oxygen vacancies (hypo-stoichiometry) is more pronounced than the effect of oxygen interstitials (hyper-stoichiometry). Then the influence of the oxygen Frenkel pairs on the thermal conductivity was calculated. The simultaneous impact of non-stoichiometry and OFP on the thermal conductivity was investigated and it was shown that the two effects can be combined using the interpretation obtained with the classical phonons scattering theory. Finally, simplified correlations were deduced for the calculation of the thermal conductivity of UO 2 taking into account the effect of non-stoichiometry and of Frenkel pairs, these two effects being present during irradiation

Pair production by a constant external field in noncommutative QED

International Nuclear Information System (INIS)

Chair, N.; Sheikh-Jabbari, M.M.

2000-09-01

In this paper we study QED on the noncommutative space in the constant electro-magnetic field background. Using the explicit solutions of the noncommutative version of Dirac equation in such background, we show that there are well-defined in and out-going asymptotic states and also there is a causal Green's function. We calculate the pair production rate in this case. We show that at tree level noncommutativity will not change the pair production and the threshold electric field. We also calculate the pair production rate considering the first loop corrections. In this case we show that the threshold electric field is decreased by the noncommutativity effects. (author)

NLO-QCD corrections to Higgs pair production in the MSSM

Energy Technology Data Exchange (ETDEWEB)

Agostini, A.; Degrassi, G. [Dipartimento di Matematica e Fisica, Università di Roma Tre, Via della Vasca Navale 84, I-00146 Rome (Italy); INFN, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146 Rome (Italy); Gröber, R. [INFN, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146 Rome (Italy); Slavich, P. [LPTHE, UPMC University Paris 06, Sorbonne Universités, 4 Place Jussieu, F-75252 Paris (France); LPTHE, CNRS, 4 Place Jussieu, F-75252 Paris (France)

2016-04-18

We take a step towards a complete NLO-QCD determination of the production of a pair of Higgs scalars in the MSSM. Exploiting a low-energy theorem that connects the Higgs-gluon interactions to the derivatives of the gluon self-energy, we obtain analytic results for the one- and two-loop squark contributions to Higgs pair production in the limit of vanishing external momenta. We find that the two-loop squark contributions can have non-negligible effects in MSSM scenarios with stop masses below the TeV scale. We also show how our results can be adapted to the case of Higgs pair production in the NMSSM.

Performance of the clover detector considering the effects of pair production

International Nuclear Information System (INIS)

Kshetri, Ritesh

2015-01-01

Gamma rays having sufficient energy to produce positron-electron pairs in a detector generate three peaks in the energy spectrum, corresponding to the full gamma-ray energy, and this gamma-ray energy minus 511 and 1022 keV because of the single and double escape of the 511 keV annihilation quanta. The escape peaks are frequently used to extend the precision of energy calibration, simply by providing additional spectral peaks at well-known energies. At energies around 6 MeV, the pair production process dominates over other gamma interaction processes in germanium. It has been observed that the intensity of the single and double escape peaks (SEP and DEP) for gamma-rays around these energies increases rapidly. This results in a difficulty to correctly identify new gamma-rays, which is crucial for precision gamma-ray spectroscopy that involves mostly the use of tapered cylindrical germanium detectors

Pair formation by a deep potential well

International Nuclear Information System (INIS)

Nikishov, A.I.

1987-01-01

We obtain solutions of the Dirac and Klein-Gordon equations for a symmetric one-dimensional potential well with a flat bottom, and arbitrary depth, width, and field strength at the walls. Quasistationary solutions are found describing pair creation by the well, and the inverse process. It is shown that when the probability of pair creation by the well is small, it can be expressed in terms of the probability of pair creation at one of the walls and the oscillation frequency of the particle in the well. Among the states of the lower continuum, there are positron resonance scattering states for supercritical well depths. The energies of these states are close to the real part of the quasistationary energy level (the Zel'dovich effect). The qualitative dependence of the transmission coefficient of the positron through the well on its energy and the well width supports the idea that the solution of the so-called one-particle Dirac equation describes a many-particle system with charge 0 or 1

Nonlinear electrostatic structures in homogeneous and inhomogeneous pair-ion plasmas

International Nuclear Information System (INIS)

Mahmood, S.; Ur-Rehman, H.; Shah, A.; Haque, Q.

2012-01-01

The nonlinear electrostatic structures such as solitons, shocks were studied in homogeneous, unmagnetized pair-ion plasma. The dissipation in the system was taken through kinematic viscosities of both pair-ion species. The one dimensional (Korteweg-de Vries-Burgers) KdVB equation was derived using reductive perturbation method. The analytical solution of KdVB equation was obtained using tanh method. It was found that solitons and monotonic shocks structures were formed in such type of plasmas depending on the value of dissipation in the system. Both compressive and refractive structures of solitons and monotonic shocks were obtained depending on the temperatures of negative and positive ions. The oscillatory shock structures in pair-ion plasmas were also obtained and its necessary conditions of formation were discussed. The acoustic solitons were also investigated in inhomogeneous unmagnetized pair-ion plasmas. The Korteweg-de Vries (KdV) like equation with an additional term due to density gradients was obtained by employing the reductive perturbation technique. It was found that amplitude of both compressive and refractive solitons was found to be enhanced as the density gradient parameter was increased. The Landau damping rates of electrostatic ion waves were studied for non-Maxwellian or Lorentzian pair-ion plasmas. The Val sov equation was solved analytically for weak damping effects in pair-ion plasma. It was found that Landau damping rate of ion plasma wave was increased in Lorentzian case in comparison with Maxwellian pair-ion plasmas. The numerical results were obtained by taking into account the parameters of pair-ion plasmas produced in laboratory experiments in Japan. (orig./A.B.)

Odd-frequency pairing in superconducting heterostructures .

Science.gov (United States)

Golubov, A. A.; Tanaka, Y.; Yokoyama, T.; Asano, Y.

2007-03-01

We present a general theory of the proximity effect in junctions between unconventional superconductors and diffusive normal metals (DN) or ferromagnets (DF). We consider all possible symmetry classes in a superconductor allowed by the Pauli principle: even-frequency spin-singlet even-parity state, even-frequency spin-triplet odd-parity state, odd-frequency spin-triplet even-parity state and odd-frequency spin-singlet odd-parity state. For each of the above states, symmetry and spectral properties of the induced pair amplitude in the DN (DF) are determined. The cases of junctions with spin-singlet s- and d-wave superconductors and spin-triplet p-wave superconductors are adressed in detail. We discuss the interplay between the proximity effect and midgap Andreev bound states arising at interfaces in unconventional (d- or p-wave) junctions. The most striking property is the odd-frequency symmetry of the pairing amplitude induced in DN (DF) in contacts with p-wave superconductors. This leads to zero-energy singularity in the density of states and to anomalous screening of an external magnetic field. Peculiarities of Josephson effect in d- or p-wave junctions are discussed. Experiments are suggested to detect an order parameter symmetry using heterostructures with unconventional superconductors.

Role of pn-pairs in nuclear structure

International Nuclear Information System (INIS)

Nie, G.K.

2003-01-01

An α-cluster model of nuclear structure based on power of proton + neutron (pn)-pairs to bind themselves to α-clusters is proposed. The α-cluster is taken as the perfect condition of coupling of 2 pn- pairs, reminding complete electron shell in atomic physics. Pn-pairs create 2 other types of coupling of considerably less power between pn-pairs of nearby α-clusters ε α c and between pn-pair not bound into α-cluster with pn-pairs of nearby cluster ε pn c . Last two types of coupling are called covalent because of reminding similar electron coupling in chemistry. According the model nucleus is a liquid drop consisting of molecules, which are α-clusters, tied by covalent coupling with those ones which are in close vicinity. Then in case of even-even nuclei spin of the nucleus has to be zero I=0 + as sum of spinless particles. In case of nucleus has some nucleons (i) in intermolecular space, I=Σj i ; with taking into account that there is coupling of p and n in pn-pair. Therefore for 6 Li (1=0)I=2·1/2=1 + . The values ε α c , ε pn c and binding energy of the pn-pair itself ε pn have been estimated from analysis of binding energy of nuclei 6 Li, 10 B and 12 C. With the values the binding energy of the other nuclei with N=Z up to 58 Cu have been described with difference between experimental values and model ones in average less than 0.4 MeV. The structure reveals some regular forms, in which every cluster has reduced amount of covalent coupling, 3 or 4, and free pn-pair has 6 covalent coupling with 3 nearby clusters pn-pairs. Then the magic numbers are supposed to be the matter of geometry, when total amount of covalent couplings is optimal (minimal for the amount of clusters), α- clusters are placed in the same fixed distant from center of mass. It means that protons of the clusters can be considered as belonging to one shell. In the cluster model single particle effects have to be considered as single particle binding in one of the surface �

Pair creation at large inherent angles

International Nuclear Information System (INIS)

Chen, P.; Tauchi, T.; Schroeder, D.V.

1992-01-01

In the next-generation linear colliders, the low-energy e + e - pairs created during the collision of high-energy e + e - beams would cause potential deleterious background problems to the detectors. At low collider energies, the pairs are made essentially by the incoherent process, where the pair is created by the interaction of beamstrahlung photons on the individual particles in the oncoming beam. This problem was first identified by Zolotarev, et al. At energies where the beamstrahlung parameter Υ lies approximately in the range 0.6 approx-lt Υ approx-lt 100, pair creation from the beamstrahlung photons is dominated by a coherent process, first noted by Chen. The seriousness of this pair creation problem lies in the transverse momenta that the pair particles carry when leaving the interaction point (IP) with large angles. Since the central issue is the transverse momentum for particles with large angles, the authors notice that there is another source for it. Namely, when the pair particles are created at low energies, the intrinsic angles of these pairs when produced may already be large. In this paper they reinvestigate the problem, following essentially the same equivalent photon approach, but with changes in specific details including the virtual photon spectrum. In addition, various assumptions are made more explicit. The formulas derived are then applied to the collider parameters designed by Palmer

Cooper pair splitters beyond the Coulomb blockade regime

Energy Technology Data Exchange (ETDEWEB)

Amitai, Ehud; Tiwari, Rakesh P.; Nigg, Simon E. [Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Walter, Stefan [Institute for Theoretical Physics, University Erlangen Nuernberg, Staudtstrasse 7, 91058 Erlangen (Germany); Schmidt, Thomas L. [Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg (Luxembourg)

2016-07-01

We consider the setup of a conventional s-wave Cooper pair splitter. However, we consider the charging energies in the quantum dots to be finite and smaller than the superconducting gap. We find analytically that at low energies the superconductor mediates an inter-dot tunneling term, the spin symmetry of which is influenced by a finite Zeeman field. This effect, together with an electrical tuning scheme of the quantum dot levels, can be used to engineer a non local triplet state on the two quantum dots, thereby extending the non-local state engineering capabilities of the Cooper pair splitter system.

Pair Interaction of Dislocations in Two-Dimensional Crystals

Science.gov (United States)

Eisenmann, C.; Gasser, U.; Keim, P.; Maret, G.; von Grünberg, H. H.

2005-10-01

The pair interaction between crystal dislocations is systematically explored by analyzing particle trajectories of two-dimensional colloidal crystals measured by video microscopy. The resulting pair energies are compared to Monte Carlo data and to predictions derived from the standard Hamiltonian of the elastic theory of dislocations. Good agreement is found with respect to the distance and temperature dependence of the interaction potential, but not regarding the angle dependence where discrete lattice effects become important. Our results on the whole confirm that the dislocation Hamiltonian allows a quantitative understanding of the formation and interaction energies of dislocations in two-dimensional crystals.

Inclusive top-pair production phenomenology with TOPIXS

NARCIS (Netherlands)

Beneke, M.; Falgari, P|info:eu-repo/dai/nl/339938897; Klein, Sebastian; Piclum, J.; Schwinn, C.; Ubiali, M.; Yan, F.

2012-01-01

We discuss various aspects of inclusive top-quark pair production based on Topixs, a new, flexible program that computes the production cross section at the Tevatron and LHC at next-to-next-to-leading logarithmic accuracy in soft and Coulomb resummation, including bound-state effects and the

Lepton-pair production in hadron-nucleus collisions

International Nuclear Information System (INIS)

Moss, J.M.; Peng, J.C.; Alde, D.M.

1989-01-01

Physics motivations for precision measurements of lepton pair production in nuclei are discussed. Preliminary results from Fermilab Experiment E772 are presented. The relevance of these results to the EMC effect and to J/ψ suppression in heavy ion collisions is also discussed. 34 refs., 17 figs

An effective potential for electron-nucleus scattering in neutrino-pair bremsstrahlung in neutron star crust

International Nuclear Information System (INIS)

Ofengeim, D D; Kaminker, A D; Yakovlev, D G

2015-01-01

We derive an analytic approximation for the emissivity of neutrino-pair bremsstrahlung (NPB) due to scattering of electrons by atomic nuclei in a neutron star (NS) crust of any realistic composition. The emissivity is expressed through generalized Coulomb logarithm by introducing an effective potential of electron-nucleus scattering. In addition, we study the conditions at which NPB in the crust is affected by strong magnetic fields and outline the main effects of the fields on neutrino emission in NSs. The results can be used for modelling of many phenomena in NSs, such as cooling of young isolated NSs, thermal relaxation of accreting NSs with overheated crust in soft X-ray transients and evolution of magnetars. (paper)

Orbitally limited pair-density-wave phase of multilayer superconductors

Science.gov (United States)

Möckli, David; Yanase, Youichi; Sigrist, Manfred

2018-04-01

We investigate the magnetic field dependence of an ideal superconducting vortex lattice in the parity-mixed pair-density-wave phase of multilayer superconductors within a circular cell Ginzburg-Landau approach. In multilayer systems, due to local inversion symmetry breaking, a Rashba spin-orbit coupling is induced at the outer layers. This combined with a perpendicular paramagnetic (Pauli) limiting magnetic field stabilizes a staggered layer dependent pair-density-wave phase in the superconducting singlet channel. The high-field pair-density-wave phase is separated from the low-field BCS phase by a first-order phase transition. The motivating guiding question in this paper is: What is the minimal necessary Maki parameter αM for the appearance of the pair-density-wave phase of a superconducting trilayer system? To address this problem we generalize the circular cell method for the regular flux-line lattice of a type-II superconductor to include paramagnetic depairing effects. Then, we apply the model to the trilayer system, where each of the layers are characterized by Ginzburg-Landau parameter κ0 and a Maki parameter αM. We find that when the spin-orbit Rashba interaction compares to the superconducting condensation energy, the orbitally limited pair-density-wave phase stabilizes for Maki parameters αM>10 .

Generalized quantum interference of correlated photon pairs

Science.gov (United States)

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

Validity of the broken-pair approximation for N = 50, even-A nuclei

International Nuclear Information System (INIS)

Haq, S.; Gambhir, Y.K.

1977-01-01

The validity of the broken-pair approximation as an approximation to the seniority shell model is investigated. The results of the broken-pair approximation and the seniority shell model, obtained by employing identical input information (single-particle levels and their energies, effective two-body matrix elements, 88 Sr inert core) for N = 50, even-A nuclei are compared. A close agreement obtained between the calculated broken-pair approximation and the seniority shell model energies for 90 Zr, 92 Mo, 94 Ru, and 96 Pd nuclei and large (95--100 %) overlaps between the broken-pair approximation and the senority shell model wave functions for 92 Mo, demonstrates the validity of the broken-pair approximation in this region and in general its usefulness as a good approximation to the seniority shell model

Time-dependent inhibition of CYP3A4 by gallic acid in human liver microsomes and recombinant systems.

Science.gov (United States)

Pu, Qiang-Hong; Shi, Liang; Yu, Chao

2015-03-01

1.Gallic acid is a main polyphenol in various fruits and plants. Inhibitory characteristics of gallic acid on CYP3A4 were still unclear. The objective of this work is hence to investigate inhibitory characteristics of gallic acid on CYP3A4 using testosterone as the probe substrate in human liver microsomes (HLMs) and recombinant CYP3A4 (rCYP3A4) systems. 2.Gallic acid caused concentration-dependent loss of CYP3A4 activity with IC50 values of 615.2 μM and 669.5 μM in HLM and rCYP3A4 systems, respectively. IC50-shift experiments showed that pre-incubation with gallic acid in the absence of NADPH contributed to 12- or 14-fold reduction of IC50 in HLM and rCYP3A4 systems, respectively, supporting a time-dependent inhibition. In HLM, time-dependent inactivation variables KI and Kinact were 485.8 μM and 0.05 min(-1), respectively. 3.Compared with the presence of NADPH, pre-incubation of gallic acid in the absence of NADPH markedly increased its inhibitory effects in HLM and rCYP3A4 systems. Those results indicate that CYP3A4 inactivation by gallic acid was independent on NADPH and was mainly mediated its oxidative products. 4.In conclusion, we showed that gallic acid weakly and time-dependently inactivated CYP3A4 via its oxidative products.

Meaningful Effect Sizes, Intraclass Correlations, and Proportions of Variance Explained by Covariates for Planning Two- and Three-Level Cluster Randomized Trials of Social and Behavioral Outcomes.

Science.gov (United States)

Dong, Nianbo; Reinke, Wendy M; Herman, Keith C; Bradshaw, Catherine P; Murray, Desiree W

2016-09-30

There is a need for greater guidance regarding design parameters and empirical benchmarks for social and behavioral outcomes to inform assumptions in the design and interpretation of cluster randomized trials (CRTs). We calculated the empirical reference values on critical research design parameters associated with statistical power for children's social and behavioral outcomes, including effect sizes, intraclass correlations (ICCs), and proportions of variance explained by a covariate at different levels (R 2 ). Children from kindergarten to Grade 5 in the samples from four large CRTs evaluating the effectiveness of two classroom- and two school-level preventive interventions. Teacher ratings of students' social and behavioral outcomes using the Teacher Observation of Classroom Adaptation-Checklist and the Social Competence Scale-Teacher. Two types of effect size benchmarks were calculated: (1) normative expectations for change and (2) policy-relevant demographic performance gaps. The ICCs and R 2 were calculated using two-level hierarchical linear modeling (HLM), where students are nested within schools, and three-level HLM, where students were nested within classrooms, and classrooms were nested within schools. Comprehensive tables of benchmarks and ICC values are provided to inform prevention researchers in interpreting the effect size of interventions and conduct power analyses for designing CRTs of children's social and behavioral outcomes. The discussion also provides a demonstration for how to use the parameter reference values provided in this article to calculate the sample size for two- and three-level CRTs designs. © The Author(s) 2016.

Identification and characterization of human UDP-glucuronosyltransferases responsible for the in-vitro glucuronidation of arctigenin.

Science.gov (United States)

Xin, Hong; Xia, Yang-Liu; Hou, Jie; Wang, Ping; He, Wei; Yang, Ling; Ge, Guang-Bo; Xu, Wei

2015-12-01

This study aimed to characterize the glucuronidation pathway of arctigenin (AR) in human liver microsomes (HLM) and human intestine microsomes (HIM). HLM and HIM incubation systems were employed to catalyse the formation of AR glucuronide. The glucuronidation activity of commercially recombinant UGT isoforms towards AR was screened. A combination of chemical inhibition assay and kinetic analysis was used to determine the UGT isoforms involved in the glucuronidation of AR in HLM and HIM. AR could be extensively metabolized to one mono-glucuronide in HLM and HIM. The mono-glucuronide was biosynthesized and characterized as 4'-O-glucuronide. UGT1A1, 1A3, 1A7, 1A8, 1A9, 1A10, 2B4, 2B7 and 2B17 participated in the formation of 4'-O-G, while UGT2B17 demonstrated the highest catalytic activity in this biotransformation. Both kinetic analysis and chemical inhibition assays demonstrated that UGT1A9, UGT2B7 and UGT2B17 played important roles in AR-4'-O-glucuronidation in HLM. Furthermore, HIM demonstrated moderate efficiency for AR-4'-O-glucuronidation, implying that AR may undergo a first-pass metabolism during the absorption process. UGT1A9, UGT2B7 and UGT2B17 were the major isoforms responsible for the 4'-O-glucuronidation of AR in HLM, while UGT2B7 and UGT2B17 were the major contributors to this biotransformation in HIM. © 2015 Royal Pharmaceutical Society.

Identification of an unusual type II thioesterase in the dithiolopyrrolone antibiotics biosynthetic pathway

Energy Technology Data Exchange (ETDEWEB)

Zhai, Ying; Bai, Silei; Liu, Jingjing; Yang, Liyuan [National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China); Han, Li; Huang, Xueshi [Institute of Microbial Pharmaceuticals, College of Life and Health Sciences, Northeastern University, Shenyang 110819 (China); He, Jing, E-mail: hejingjj@mail.hzau.edu.cn [National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China)

2016-04-22

Dithiolopyrrolone group antibiotics characterized by an electronically unique dithiolopyrrolone heterobicyclic core are known for their antibacterial, antifungal, insecticidal and antitumor activities. Recently the biosynthetic gene clusters for two dithiolopyrrolone compounds, holomycin and thiomarinol, have been identified respectively in different bacterial species. Here, we report a novel dithiolopyrrolone biosynthetic gene cluster (aut) isolated from Streptomyces thioluteus DSM 40027 which produces two pyrrothine derivatives, aureothricin and thiolutin. By comparison with other characterized dithiolopyrrolone clusters, eight genes in the aut cluster were verified to be responsible for the assembly of dithiolopyrrolone core. The aut cluster was further confirmed by heterologous expression and in-frame gene deletion experiments. Intriguingly, we found that the heterogenetic thioesterase HlmK derived from the holomycin (hlm) gene cluster in Streptomyces clavuligerus significantly improved heterologous biosynthesis of dithiolopyrrolones in Streptomyces albus through coexpression with the aut cluster. In the previous studies, HlmK was considered invalid because it has a Ser to Gly point mutation within the canonical Ser-His-Asp catalytic triad of thioesterases. However, gene inactivation and complementation experiments in our study unequivocally demonstrated that HlmK is an active distinctive type II thioesterase that plays a beneficial role in dithiolopyrrolone biosynthesis. - Highlights: • Cloning of the aureothricin biosynthetic gene cluster from Streptomyces thioluteus DSM 40027. • Identification of the aureothricin gene cluster by heterologous expression and in-frame gene deletion. • The heterogenetic thioesterase HlmK significantly improved dithiolopyrrolones production of the aureothricin gene cluster. • Identification of HlmK as an unusual type II thioesterase.

Identification of an unusual type II thioesterase in the dithiolopyrrolone antibiotics biosynthetic pathway

International Nuclear Information System (INIS)

Zhai, Ying; Bai, Silei; Liu, Jingjing; Yang, Liyuan; Han, Li; Huang, Xueshi; He, Jing

2016-01-01

Dithiolopyrrolone group antibiotics characterized by an electronically unique dithiolopyrrolone heterobicyclic core are known for their antibacterial, antifungal, insecticidal and antitumor activities. Recently the biosynthetic gene clusters for two dithiolopyrrolone compounds, holomycin and thiomarinol, have been identified respectively in different bacterial species. Here, we report a novel dithiolopyrrolone biosynthetic gene cluster (aut) isolated from Streptomyces thioluteus DSM 40027 which produces two pyrrothine derivatives, aureothricin and thiolutin. By comparison with other characterized dithiolopyrrolone clusters, eight genes in the aut cluster were verified to be responsible for the assembly of dithiolopyrrolone core. The aut cluster was further confirmed by heterologous expression and in-frame gene deletion experiments. Intriguingly, we found that the heterogenetic thioesterase HlmK derived from the holomycin (hlm) gene cluster in Streptomyces clavuligerus significantly improved heterologous biosynthesis of dithiolopyrrolones in Streptomyces albus through coexpression with the aut cluster. In the previous studies, HlmK was considered invalid because it has a Ser to Gly point mutation within the canonical Ser-His-Asp catalytic triad of thioesterases. However, gene inactivation and complementation experiments in our study unequivocally demonstrated that HlmK is an active distinctive type II thioesterase that plays a beneficial role in dithiolopyrrolone biosynthesis. - Highlights: • Cloning of the aureothricin biosynthetic gene cluster from Streptomyces thioluteus DSM 40027. • Identification of the aureothricin gene cluster by heterologous expression and in-frame gene deletion. • The heterogenetic thioesterase HlmK significantly improved dithiolopyrrolones production of the aureothricin gene cluster. • Identification of HlmK as an unusual type II thioesterase.

Pairing symmetry transitions in the even-denominator FQHE system

International Nuclear Information System (INIS)

Nomura, Kentaro; Yoshioka, Daijiro

2001-01-01

Transitions from a paired quantum Hall state to another quantum Hall state in bilayer systems are discussed in the framework of the edge theory. Starting from the edge theory for the Haldane-Rezayi state, it is shown that the charging effect of a bilayer system which breaks the SU (2) symmetry of the pseudospin shifts the central charge and the conformal dimensions of the fermionic fields which describe the pseudospin sector in the edge theory. This corresponds to the transition from the Haldane-Rezayi state to Halperin's 331 state, or from a singlet d-wave to a triplet p-wave ABM type paired state in the composite fermion picture. Considering interlayer tunneling, the tunneling rate-capacitance phase diagram for the ν=5/2 paired bilayer system is discussed. (author)

Pairing Symmetry Transitions in the Even-Denominator FQHE System

Science.gov (United States)

Nomura, Kentaro; Yoshioka, Daijiro

2001-12-01

Transitions from a paired quantum Hall state to another quantum Hall state in bilayer systems are discussed in the framework of the edge theory. Starting from the edge theory for the Haldane Rezayi state, it is shown that the charging effect of a bilayer system which breaks the SU(2) symmetry of the pseudospin shifts the central charge and the conformal dimensions of the fermionic fields which describe the pseudospin sector in the edge theory. This corresponds to the transition from the Haldane Rezayi state to Halperin's 331 state, or from a singlet d-wave to a triplet p-wave ABM type paired state in the composite fermion picture. Considering interlayer tunneling, the tunneling rate-capacitance phase diagram for the ν=5/2 paired bilayer system is discussed.

Hadronic production of lepton pairs (experimental)

International Nuclear Information System (INIS)

Boucrot, J.

1980-12-01

Hadonic production of lepton pairs has become a good testground of Q.C.D. The large effects predicted in cross sections and in Psub(T) distributions are seen and may be one of the good indirect proofs of the existence of gluons. Detailed experimental results are available, and clearly it is necessary that higher order Q.C.D. corrections should be estimated

Heteroditopic receptors for ion-pair recognition.

Science.gov (United States)

McConnell, Anna J; Beer, Paul D

2012-05-21

Ion-pair recognition is a new field of research emerging from cation and anion coordination chemistry. Specific types of heteroditopic receptor designs for ion pairs and the complexity of ion-pair binding are discussed to illustrate key concepts such as cooperativity. The importance of this area of research is reflected by the wide variety of potential applications of ion-pair receptors, including applications as membrane transport and salt solubilization agents and sensors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assessing Intimacy: The Pair Inventory.

Science.gov (United States)

Schaefer, Mark T.; Olson, David H.

1981-01-01

Personal Assessment of Intimacy in Relationships (PAIR) provides systematic information in five types of intimacy: emotional, social, sexual, intellectual and recreational. PAIR can be used with couples in marital therapy and enrichment groups. (Author)

The Effects of a Roommate-Pairing Program on International Student Satisfaction and Academic Success

OpenAIRE

Tolman, Steven

2017-01-01

While great attention has been given to the growth of international students at U.S. institutions, there is a gap in the literature examining support for this student population within residence halls. To address the gap, this quantitative study evaluated an international roommate-pairing program (IRP) by comparing the residential experience of IRP participants with a control group. The results showed the roommate-pairing program had a positive impact on the residential expe...

Spectroscopy of metal "superatom" nanoclusters and high-Tc superconducting pairing

Science.gov (United States)

Halder, Avik; Kresin, Vitaly V.

2015-12-01

A unique property of metal nanoclusters is the "superatom" shell structure of their delocalized electrons. The electronic shell levels are highly degenerate and therefore represent sharp peaks in the density of states. This can enable exceptionally strong electron pairing in certain clusters composed of tens to hundreds of atoms. In a finite system, such as a free nanocluster or a nucleus, pairing is observed most clearly via its effect on the energy spectrum of the constituent fermions. Accordingly, we performed a photoionization spectroscopy study of size-resolved aluminum nanoclusters and observed a rapid rise in the near-threshold density of states of several clusters (A l37 ,44 ,66 ,68 ) with decreasing temperature. The characteristics of this behavior are consistent with compression of the density of states by a pairing transition into a high-temperature superconducting state with Tc≳100 K. This value exceeds that of bulk aluminum by two orders of magnitude. These results highlight the potential of novel pairing effects in size-quantized systems and the possibility to attain even higher critical temperatures by optimizing the particles' size and composition. As a new class of high-temperature superconductors, such metal nanocluster particles are promising building blocks for high-Tc materials, devices, and networks.

Enol tautomers of Watson-Crick base pair models are metastable because of nuclear quantum effects.

Science.gov (United States)

Pérez, Alejandro; Tuckerman, Mark E; Hjalmarson, Harold P; von Lilienfeld, O Anatole

2010-08-25

Intermolecular enol tautomers of Watson-Crick base pairs could emerge spontaneously via interbase double proton transfer. It has been hypothesized that their formation could be facilitated by thermal fluctuations and proton tunneling, and possibly be relevant to DNA damage. Theoretical and computational studies, assuming classical nuclei, have confirmed the dynamic stability of these rare tautomers. However, by accounting for nuclear quantum effects explicitly through Car-Parrinello path integral molecular dynamics calculations, we find the tautomeric enol form to be dynamically metastable, with lifetimes too insignificant to be implicated in DNA damage.

Distributed Pair Programming Using Collaboration Scripts: An Educational System and Initial Results

Science.gov (United States)

Tsompanoudi, Despina; Satratzemi, Maya; Xinogalos, Stelios

2015-01-01

Since pair programming appeared in the literature as an effective method of teaching computer programming, many systems were developed to cover the application of pair programming over distance. Today's systems serve personal, professional and educational purposes allowing distributed teams to work together on the same programming project. The…

arXiv Higgs boson pair production at NNLO with top quark mass effects

CERN Document Server

Grazzini, Massimiliano; Jones, Stephen; Kallweit, Stefan; Kerner, Matthias; Lindert, Jonas M.; Mazzitelli, Javier

2018-05-09

We consider QCD radiative corrections to Higgs boson pair production through gluon fusion in proton collisions. We combine the exact next-to-leading order (NLO) contribution, which features two-loop virtual amplitudes with the full dependence on the top quark mass M$_{t}$ , with the next-to-next-to-leading order (NNLO) corrections computed in the large-M$_{t}$ approximation. The latter are improved with different reweighting techniques in order to account for finite-M$_{t}$ effects beyond NLO. Our reference NNLO result is obtained by combining one-loop double-real corrections with full M$_{t}$ dependence with suitably reweighted real-virtual and double-virtual contributions evaluated in the large-M$_{t}$ approximation. We present predictions for inclusive cross sections in pp collisions at $ \\sqrt{s} $ = 13, 14, 27 and 100 TeV and we discuss their uncertainties due to missing M$_{t}$ effects. Our approximated NNLO corrections increase the NLO result by an amount ranging from +12% at $ \\sqrt{s}=13 $ TeV to +7%...

Structural Context Effects in the Oxidation of 8-Oxo-7,8-dihydro-2’-deoxyguanosine to Hydantoin Products: Electrostatics, Base Stacking, and Base Pairing

Science.gov (United States)

Fleming, Aaron M.; Muller, James G.; Dlouhy, Adrienne C.; Burrows, Cynthia J.

2012-01-01

8-Oxo-7,8-dihydroguanine (OG) is the most common base damage found in the cell where it resides in many structural contexts including the nucleotide pool, single-stranded DNA at transcription forks and replication bubbles, and in duplex DNA base paired with either A or C. OG is prone to further oxidation to the highly mutagenic hydantoin products, spiroiminodihydantoin (Sp) and 5-guanidinohydantoin (Gh) in a sharply pH-dependent fashion within nucleosides. In the present work, studies were conducted to determine how the structural context affects OG oxidation to the hydantoins. These studies revealed a trend in which the Sp yield was greatest in unencumbered contexts, such as nucleosides, while the Gh yield increased in oligodeoxynucleotide (ODN) contexts or at reduced pH. Oxidation of oligomers containing hydrogen bond modulators (2,6-diaminopurine, N4-ethylcytidine) or alteration of the reaction conditions (pH, temperature, and salt) identify base stacking, electrostatics and base pairing as the drivers of the key intermediate 5-hydroxy-8-oxo-7,8-dihydroguanine (5-HO-OG) partitioning along the two hydantoin pathways, allowing us to propose a mechanism for the observed base pairing effects. Moreover, these structural effects cause an increase in the effective pKa of 5-HO-OG following an increasing trend from 5.7 in nucleosides to 7.7 in a duplex bearing an OG•C base pair, which supports the context-dependent product yields. The high yield of Gh in ODNs underscores the importance of further study on this lesion. The structural context of OG also determined its relative reactivity toward oxidation for which the OG•A base pair is ~2.5-fold more reactive than an OG•C base pair, and with the weak one-electron oxidant ferricyanide, the OG nucleoside reactivity is >6000-fold greater than that of OG•C in a duplex, leading to the conclusion that OG in the nucleoside pool should act as a protective agent for OG in the genome. PMID:22880947

Existence and consequences of Coulomb pairing of electrons in a solid

International Nuclear Information System (INIS)

Mahajan, S.M.; Thyagaraja, A.

1996-11-01

It is shown from first principles that, in the periodic potential of a crystalline solid, short-range (i.e., screened) binary Coulomb interactions can lead to a two-electron bound state. It is further suggested that these composite bosonic states (charge -2e, and typically spin zero) could mediate an effectively attractive interaction between pairs of conduction electrons close to the Fermi level. This necessarily short range attractive interaction, which is crucially dependent on the band structure of the solid, and is complementary to the phonon-mediated one, may provide a source for the existence and properties of short correlation-length electron pairs (analogous to but distinct from Cooper pairs) needed to understand high temperature superconductivity. Several distinctive and observable characteristics of the proposed pairing scheme are discussed

Laser driven electron-positron pair creation-kinetic theory versus analytical approximations

International Nuclear Information System (INIS)

Smolyansky, S.A.; Prozorkevich, A.V.; Bonitz, M.

2013-01-01

The dynamical Schwinger effect of vacuum pair creation driven by an intense external laser pulse is studied on the basis of quantum kinetic theory. The numerical solutions of these kinetic equations exhibit a complex time dependence which makes an analysis of the physical processes difficult. In particular, the question of secondary effects, such as creation of secondary annihilation photons from the focus spot of the colliding laser beams, remains an important open problem. In the present work we, therefore, develop a perturbation theory which is able to capture the dominant time dependence of the produced electron-positron pair density. The theory shows excellent agreement with the exact kinetic results during the laser pulse, but fails to reproduce the residual pair density remaining in the system after termination of the pulse. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Multilevel Analysis of Employee Satisfaction on Commitment to Organizational Culture: Case Study of Chinese State-Owned Enterprises

Directory of Open Access Journals (Sweden)

Fangtao Liu

2017-11-01

Full Text Available This study analyzes the effects of employee satisfaction and demographic indicators on employee commitment to organizational culture at the enterprise level. With data from a survey of 3029 employees from 27 state-owned enterprises (SOEs, a hierarchical linear model (HLM is used to identify the influencing factors of employee commitment to organizational culture at the enterprise level. An empirical study indicates that apart from the factors of employee satisfaction and demographic background, four contextual variables of enterprises, namely, comprehensive management, energy intensity, cost-income ratio, and capacity-load ratio, also influence commitment to organizational culture levels. Results show that applying HLM can substantially improve the explanatory power of employee satisfaction factors on commitment to organizational culture using nested enterprise contextual variables. Although measurement scales and satisfaction models have been proposed over the years, only a few studies have addressed the particular nature inherent in Chinese SOEs. HLM, which accounts for the nested data structure and determines the effects of employee satisfaction factors on commitment to organizational culture without bias, is developed in this study. Through an insider view based on empirical work, this research can improve the ability of senior managers to understand the culture and dynamics of organizations, to deliver strong leadership, and to enhance corporate internal management.

Effect of temperature dependence of the Langmuir constant molecular pair potentials on gas hydrates formation mechanism

Energy Technology Data Exchange (ETDEWEB)

Mokhtari, B.; Enayati, M. [Iranian Offshore Oil Co., Tehran (Iran, Islamic Republic of); Heidaryan, E. [Islamic Azad Univ., Tehran (Iran, Islamic Republic of). Masjidosolayman Branch

2008-07-01

Theoretical methods show that crystalline hydrates can form from single-phase systems consisting of both vapor water with gaseous hydrate former and liquid water with dissolved hydrate former. Two phase systems consist of both liquid water with gaseous hydrate former and with liquid hydrate former on the surface. This paper presented a Langmuir constant related model for the prediction of equilibrium pressures and cage occupancies of pure component hydrates. Intermolecular potentials were fit to quantum mechanical energies to obtain the Langmuir constants, which differed from the procedure utilized with the vdWP model. The paper described the experimental method and model calculations. This included the Fugacity model and Van der Waals and Platteeuw model. The paper also discussed pair potential of non-spherical molecules, including the multicentre (site-site) potential; Gaussian overlap potential; Lennard-Jones potential; and Kihara generalized pair potential. It was concluded that fraction of occupied cavities is a function of pair potentials between hard core and empty hydrate lattice. These pair potentials could be calculated from some model as Kihara cell potential, Gaussian potential, Lennard-Jones potential and multicentre pair potential. 49 refs., 3 figs.

Repeatedly pairing vagus nerve stimulation with a movement reorganizes primary motor cortex.

Science.gov (United States)

Porter, Benjamin A; Khodaparast, Navid; Fayyaz, Tabbassum; Cheung, Ryan J; Ahmed, Syed S; Vrana, William A; Rennaker, Robert L; Kilgard, Michael P

2012-10-01

Although sensory and motor systems support different functions, both systems exhibit experience-dependent cortical plasticity under similar conditions. If mechanisms regulating cortical plasticity are common to sensory and motor cortices, then methods generating plasticity in sensory cortex should be effective in motor cortex. Repeatedly pairing a tone with a brief period of vagus nerve stimulation (VNS) increases the proportion of primary auditory cortex responding to the paired tone (Engineer ND, Riley JR, Seale JD, Vrana WA, Shetake J, Sudanagunta SP, Borland MS, Kilgard MP. 2011. Reversing pathological neural activity using targeted plasticity. Nature. 470:101-104). In this study, we predicted that repeatedly pairing VNS with a specific movement would result in an increased representation of that movement in primary motor cortex. To test this hypothesis, we paired VNS with movements of the distal or proximal forelimb in 2 groups of rats. After 5 days of VNS movement pairing, intracranial microstimulation was used to quantify the organization of primary motor cortex. Larger cortical areas were associated with movements paired with VNS. Rats receiving identical motor training without VNS pairing did not exhibit motor cortex map plasticity. These results suggest that pairing VNS with specific events may act as a general method for increasing cortical representations of those events. VNS movement pairing could provide a new approach for treating disorders associated with abnormal movement representations.

Motor Development and Physical Activity: A Longitudinal Discordant Twin-Pair Study.

Science.gov (United States)

Aaltonen, Sari; Latvala, Antti; Rose, Richard J; Pulkkinen, Lea; Kujala, Urho M; Kaprio, Jaakko; Silventoinen, Karri

2015-10-01

Previous longitudinal research suggests that motor proficiency in early life predicts physical activity in adulthood. Familial effects including genetic and environmental factors could explain the association, but no long-term follow-up studies have taken into account potential confounding by genetic and social family background. The present twin study investigated whether childhood motor skill development is associated with leisure-time physical activity levels in adulthood independent of family background. Altogether, 1550 twin pairs from the FinnTwin12 study and 1752 twin pairs from the FinnTwin16 study were included in the analysis. Childhood motor development was assessed by the parents' report of whether one of the co-twins had been ahead of the other in different indicators of motor skill development in childhood. Leisure-time physical activity (MET·h·d) was self-reported by the twins in young adulthood and adulthood. Statistical analyses included conditional and ordinary linear regression models within twin pairs. Using all activity-discordant twin pairs, the within-pair difference in a sum score of motor development in childhood predicted the within-pair difference in the leisure-time physical activity level in young adulthood (P men and women.

On a method for constructing the Lax pairs for nonlinear integrable equations

International Nuclear Information System (INIS)

Habibullin, I T; Poptsova, M N; Khakimova, A R

2016-01-01

We suggest a direct algorithm for searching the Lax pairs for nonlinear integrable equations. It is effective for both continuous and discrete models. The first operator of the Lax pair corresponding to a given nonlinear equation is found immediately, coinciding with the linearization of the considered nonlinear equation. The second one is obtained as an invariant manifold to the linearized equation. A surprisingly simple relation between the second operator of the Lax pair and the recursion operator is discussed: the recursion operator can immediately be found from the Lax pair. Examples considered in the article are convincing evidence that the found Lax pairs differ from the classical ones. The examples also show that the suggested objects are true Lax pairs which allow the construction of infinite series of conservation laws and hierarchies of higher symmetries. In the case of the hyperbolic type partial differential equation our algorithm is slightly modified; in order to construct the Lax pairs from the invariant manifolds we use the cutting off conditions for the corresponding infinite Laplace sequence. The efficiency of the method is illustrated by application to some equations given in the Svinolupov–Sokolov classification list for which the Lax pairs and the recursion operators have not been found earlier. (paper)

Ion pairing in ionic liquids

International Nuclear Information System (INIS)

Kirchner, Barbara; Malberg, Friedrich; Firaha, Dzmitry S; Hollóczki, Oldamur

2015-01-01

In the present article we briefly review the extensive discussion in literature about the presence or absence of ion pair-like aggregates in ionic liquids. While some experimental studies point towards the presence of neutral subunits in ionic liquids, many other experiments cannot confirm or even contradict their existence. Ion pairs can be detected directly in the gas phase, but no direct method is available to observe such association behavior in the liquid, and the corresponding indirect experimental proofs are based on such assumptions as unity charges at the ions. However, we have shown by calculating ionic liquid clusters of different sizes that assuming unity charges for ILs is erroneous, because a substantial charge transfer is taking place between the ionic liquid ions that reduce their total charge. Considering these effects might establish a bridge between the contradicting experimental results on this matter. Beside these results, according to molecular dynamics simulations the lifetimes of ion–ion contacts and their joint motions are far too short to verify the existence of neutral units in these materials. (topical review)

Observation of aggregation triggered by Resonance Energy Transfer (RET) induced intermolecular pairing force.

Science.gov (United States)

Pan, Xiaoyong; Wang, Weizhi; Ke, Lin; Zhang, Nan

2017-07-20

In this report, we showed the existence of RET induced intermolecular pairing force by comparing their fluorescence behaviors under room illumination vs standing in dark area for either PFluAnt solution or PFluAnt&PFOBT mixture. Their prominent emission attenuation under room illumination brought out the critical role of photo, i.e. RET induced intermolecular pairing force in induction of polymer aggregation. Constant UV-Vis absorption and fluorescence spectra in terms of both peak shapes and maximum wavelengths implied no chemical decomposition was involved. Recoverable fluorescence intensity, fluorescence lifetime as well as NMR spectra further exclude photo induced decomposition. The controllable on/off state of RET induced intermolecular pairing force was verified by the masking effect of outside PFluAnt solution which function as filter to block the excitation of inside PFluAnt and thus off the RET induced intermolecular pairing force. Theoretical calculation suggest that magnitude of RET induced intermolecular pairing force is on the same scale as that of van der Waals interaction. Although the absolute magnitude of RET induced intermolecular pairing force was not tunable, its effect can be magnified by intentionally turn it "on", which was achieved by irradiance with 5 W desk lamp in this report.

Transverse spin effects in hadron-pair production from semi-inclusive deep inelastic scattering

CERN Document Server

Adolph, C.; Alexakhin, V.Yu.; Alexeev, G.D.; Amoroso, A.; Antonov, A.A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Bedfer, Y.; Bernhard, J.; Bertini, R.; Bettinelli, M.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Braun, C.; Bravar, A.; Bressan, A.; Burtin, E.; Chaberny, D.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Crespo, M.L.; Dalla Torre, S.; Das, S.; Dasgupta, S.S.; Dhara, L.; Donskov, S.V.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; jr., M.Finger; Fischer, H.; Franco, C.; Friedrich, J.M.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gazda, R.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Grabmuller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Guthorl, T.; Haas, F.; von Harrach, D.; Heinsius, F.H.; Herrmann, F.; Hess, C.; Hinterberger, F.; Horikawa, N.; Hoppner, Ch.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, O.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jasinski, P.; Joosten, R.; Kabuss, E.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Konigsmann, K.; Konstantinov, V.F.; Korzenev, A.; Kotzinian, A.M.; Kramer, M.; Kroumchtein, Z.V.; Kunne, F.; Kurek, K.; Lauser, L.; Lednev, A.A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.K.; Mann, A.; Marchand, C.; Martin, A.; Marzec, J.; Massmann, F.; Matsuda, T.; Meyer, W.; Michigami, T.; Mikhailov, Yu.V.; Moinester, M.A.; Morreale, A.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Nowak, W.D.; Nunes, A.S.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Perevalova, E.; Pesaro, G.; Peshekhonov, D.V.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pontecorvo, G.; Pretz, J.; Quaresma, M.; Quintans, C.; Rajotte, J.F.; Ramos, S.; Rapatsky, V.; Reicherz, G.; Richter, A.; Rondio, E.; Rossiyskaya, N.S.; Ryabchikov, D.I.; Samoylenko, V.D.; Sandacz, A.; Sapozhnikov, M.G.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schluter, T.; Schmidt, K.; Schmitt, L.; Schonning, K.; Schopferer, S.; Schott, M.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Slunecka, M.; Smirnov, G.I.; Sosio, S.; Sozzi, F.; Srnka, A.; Stolarski, M.; Sulc, M.; Sulej, R.; Sznajder, P.; Takekawa, S.; Wolbeek, J.Ter; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.G.; Uhl, S.; Uman, I.; Vandenbroucke, M.; Virius, M.; Vlassov, N.V.; Vossen, A.; Wang, L.; Windmolders, R.; Wislicki, W.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zhuravlev, N.; Zvyagin, A.

2012-06-18

First measurements of azimuthal asymmetries in hadron-pair production in deep-inelastic scattering of muons on transversely polarised ^6LiD (deuteron) and NH_3 (proton) targets are presented. The data were taken in the years 2002-2004 and 2007 with the COMPASS spectrometer using a muon beam of 160 GeV/c at the CERN SPS. The asymmetries provide access to the transversity distribution functions, without involving the Collins effect as in single hadron production. The sizeable asymmetries measured on the NH_ target indicate non-vanishing u-quark transversity and two-hadron interference fragmentation functions. The small asymmetries measured on the ^6LiD target can be interpreted as indication for a cancellation of u- and d-quark transversities.

Virialization in N-body models of the expanding universe. I. Isolated pairs

International Nuclear Information System (INIS)

Evrard, A.E.; Yahil, A.; and Institute of Astronomy, University of Cambridge)

1985-01-01

The degree of virialization of isolated pairs of galaxies is investigated in the N-body simulations of Efstathiou and Eastwood for open (Ω 0 = 0.1) and critical (Ω 0 = 1.0) universes, utilizing the three-dimensional information available for both position and velocity. Roughly half of the particles in the models form isolated pairs whose dynamics is dominated by their own two-body force. Three-quarters or more of these pairs are bound, and this ensemble of bound isolated pairs is found to yield excellent mass estimates upon application of the virial theorem. Contamination from unbound pairs introduces error factors smaller than 2 in mass estimates, and these errors can be corrected by simple methods. Oribts of bound pairs are highly eccentric, but this does not lead to serious selection effects in orbital phases, since these are uniformly distributed. The relative velocity of these pairs of mass points shows a Keplerian falloff with separation, contrary to observational evidence for real galaxies. All the above results are independent of the value of Ω 0 , but may be sensitive to initial conditions and the point-mass nature of the particles

Higgs pair production at NLO QCD for CP-violating Higgs sectors

Science.gov (United States)

Gröber, R.; Mühlleitner, M.; Spira, M.

2017-12-01

Higgs pair production through gluon fusion is an important process at the LHC to test the dynamics underlying electroweak symmetry breaking. Higgs sectors beyond the Standard Model (SM) can substantially modify this cross section through novel couplings not present in the SM or the on-shell production of new heavy Higgs bosons that subsequently decay into Higgs pairs. CP violation in the Higgs sector is important for the explanation of the observed matter-antimatter asymmetry through electroweak baryogenesis. In this work we compute the next-to-leading order (NLO) QCD corrections in the heavy top quark limit, including the effects of CP violation in the Higgs sector. We choose the effective theory (EFT) approach, which provides a rather model-independent way to explore New Physics (NP) effects by adding dimension-6 operators, both CP-conserving and CP-violating ones, to the SM Lagrangian. Furthermore, we perform the computation within a specific UV-complete model and choose as benchmark model the general 2-Higgs-Doublet Model with CP violation, the C2HDM. Depending on the dimension-6 coefficients, the relative NLO QCD corrections are affected by several per cent through the new CP-violating operators. This is also the case for SM-like Higgs pair production in the C2HDM, while the relative QCD corrections in the production of heavier C2HDM Higgs boson pairs deviate more strongly from the SM case. The absolute cross sections both in the EFT and the C2HDM can be modified by more than an order of magnitude. In particular, in the C2HDM the resonant production of Higgs pairs can by far exceed the SM cross section.

In vitro effects of amodiaquine on paired Schistosoma mansoni adult worms at concentrations of less than 5 µg/mL

Directory of Open Access Journals (Sweden)

Kentaro Kato

2013-04-01

Full Text Available In this study, the in vitro effects of amodiaquine (AQ monotherapy on the egg output of paired adult Schistosoma mansoni worms and their survival during in vitro culture were assessed. In addition, the gross morphological alterations of male and female worms caused by AQ were visually observed under a dissecting microscope. AQ significantly reduced the daily egg output of paired adult S. mansoni worms following incubation for 14 days at 1-5 µg/mL, but not at 0.5 µg/mL, compared with the control group. AQ also reduced the survival of male and female worms at concentrations of 2 and 5 µg/mL, respectively. Moreover, exposure to 5 µg/mL AQ caused severe swelling and/or localisation of black content in the body of all male and female worms within one or two days of incubation; subsequently, shrinkage in the male worms and elongation in the female worms were observed. The initial morphological alterations caused by AQ occurred along the intestinal tract of the male and female worms. To our knowledge, this is the first study to report not only the efficacy of AQ at concentrations lower than 5 µg/mL on paired adult S. mansoni worms, but also the effects of AQ on the intestinal tracts of worms in in vitro culture.

Variation in parent–offspring kinship in socially monogamous systems with extra‐pair reproduction and inbreeding

Science.gov (United States)

Reid, Jane M.; Bocedi, Greta; Nietlisbach, Pirmin; Duthie, A. Bradley; Wolak, Matthew E.; Gow, Elizabeth A.; Arcese, Peter

2016-01-01

Female extra‐pair reproduction in socially monogamous systems is predicted to cause cuckolded socially‐paired males to conditionally reduce paternal care, causing selection against extra‐pair reproduction and underlying polyandry. However, existing models and empirical studies have not explicitly considered that cuckolded males might be related to their socially‐paired female and/or to her extra‐pair mate, and therefore be related to extra‐pair offspring that they did not sire but could rear. Selection against paternal care, and hence against extra‐pair reproduction, might then be weakened. We derive metrics that quantify allele‐sharing between within‐pair and extra‐pair offspring and their mother and her socially‐paired male in terms of coefficients of kinship and inbreeding. We use song sparrow (Melospiza melodia) paternity and pedigree data to quantify these metrics, and thereby quantify the joint effects of extra‐pair reproduction and inbreeding on a brood's total allelic value to its socially‐paired parents. Cuckolded male song sparrows were almost always detectably related to extra‐pair offspring they reared. Consequently, although brood allelic value decreased substantially following female extra‐pair reproduction, this decrease was reduced by within‐pair and extra‐pair reproduction among relatives. Such complex variation in kinship within nuclear families should be incorporated into models considering coevolutionary dynamics of extra‐pair reproduction, parental care, and inbreeding. PMID:27174154

Influence of Leaders' Psychological Capital on Their Followers: Multilevel Mediation Effect of Organizational Identification

Science.gov (United States)

Chen, Qishan; Wen, Zhonglin; Kong, Yurou; Niu, Jun; Hau, Kit-Tai

2017-01-01

We investigated the relationships between leaders' and their followers' psychological capital and organizational identification in a Chinese community. Participants included 423 followers on 34 work teams, each with its respective team leader. Hierarchical linear models (HLM) were used in the analyses to delineate the relationships among participants' demographic background (gender, age, marital status, and educational level), human capital, and tenure. The results revealed that leaders' psychological capital positively influenced their followers' psychological capital through the mediation effect of enhancing followers' organizational identification. The implications of these findings, the study's limitations, and directions for future research are discussed. PMID:29075218

Magnetic Pair Creation Transparency in Pulsars

Science.gov (United States)

Story, Sarah; Baring, M. G.

2013-04-01

The Fermi gamma-ray pulsar database now exceeds 115 sources and has defined an important part of Fermi's science legacy, providing rich information for the interpretation of young energetic pulsars and old millisecond pulsars. Among the well established population characteristics is the common occurrence of exponential turnovers in the 1-10 GeV range. These turnovers are too gradual to arise from magnetic pair creation in the strong magnetic fields of pulsar inner magnetospheres, so their energy can be used to provide lower bounds to the typical altitude of GeV band emission. We explore such constraints due to single-photon pair creation transparency below the turnover energy. We adopt a semi-analytic approach, spanning both domains when general relativistic influences are important and locales where flat spacetime photon propagation is modified by rotational aberration effects. Our work clearly demonstrates that including near-threshold physics in the pair creation rate is essential to deriving accurate attenuation lengths. The altitude bounds, typically in the range of 2-6 neutron star radii, provide key information on the emission altitude in radio quiet pulsars that do not possess double-peaked pulse profiles. For the Crab pulsar, which emits pulsed radiation up to energies of 120 GeV, we obtain a lower bound of around 15 neutron star radii to its emission altitude.

Analysis and optimization of kinematic pair force in control rod drive mechanism

International Nuclear Information System (INIS)

Sun Zhenguo; Liu Sen; Ran Xiaobing; Dai Changnian; Li Yuezhong

2015-01-01

Function expressions of kinematic pair force with latch dimensions, friction coefficient, link angle and external load was obtained by theoretical analysis, and the expression was verified by the motion analysis software. Key parameters of kinematic pair were confirmed, and their effect trends with force of parts were obtained. They show that the available method of kinematic pair optimization is increasing the space of latch holes. Using the motion analysis software, the forces of parts before and after optimization was compared. The result shows that the forces of parts were improved after the optimization. (authors)

Crossover from phonon-mediated to repulsion-induced superconducting pairing with large momentum

International Nuclear Information System (INIS)

Belyavsky, V.I.; Kopaev, Yu.V.; Nguyen, N.T.; Togushova, Yu.N.

2005-01-01

There are asymmetric and symmetric solutions of the self-consistency equation which takes into account both phonon-mediated and Coulomb pairing interactions. The first of them leads to the order parameter with a nodal line and, in the case of pairing with large momentum, exists at any repulsive and attractive strengths. The second one arises if the attraction exceeds a level depending on the repulsion strength and dominates the pairing in the strong attraction limit. The competition of attraction and repulsion results in unusual isotope-effect exponent observed in the cuprates

Study of neutron-proton pairing in N=Z unstable nuclei through transfer reactions

International Nuclear Information System (INIS)

Le Crom, B.

2016-01-01

A nucleus is described as a set of independent neutrons and protons linked by a mean-field potential. However, in order to have a better description one needs to take into account some residual interactions such as pairing. Neutron-neutron and proton-proton pairings are well-studied but neutron-proton pairing is not well-known. np pairing can be isovector pairing such as nn and pp pairing or isoscalar which is yet unknown. Over-binding of N=Z nuclei could be a manifestation of np pairing. We have studied np pairing through transfer reactions. In this case, the cross-section of np pair transfer is expected to be enhanced in the presence of important np pairing. np pairing is expected to be important in N=Z nuclei with high J orbitals. Since the development of radioactive beam facilities, such beams are only available. The experiment was performed at GANIL with an efficient set-up so as to detect products from the (p, 3 He) transfer reaction. This reaction is affected by isovector and isoscalar np pairing. We used 56 Ni and 52 Fe beams so as to see the effect of the occupancy of 0f 7/2 shell on the np pairing. First, we analysed the data from the 56 Ni(p,d) 55 Ni reaction and we compared the results with the literature to validate analysis procedure. After analysing data from the 56 Ni(p, 3 He) 54 Co reaction and extracting the population of the various states of 54 Co, we obtained information about the relative intensity between isoscalar and isovector np pairing in 56 Ni showing the predominance of isovector np pairing in this nucleus. Moreover, in the framework of developing a new charged particle detector, research on the discrimination of light nuclei using pulse shape analysis was performed and is also presented. (author)

Topological Nodal Cooper Pairing in Doped Weyl Metals

Science.gov (United States)

Li, Yi; Haldane, F. D. M.

2018-02-01

We generalize the concept of Berry connection of the single-electron band structure to that of a two-particle Cooper pairing state between two Fermi surfaces with opposite Chern numbers. Because of underlying Fermi surface topology, the pairing Berry phase acquires nontrivial monopole structure. Consequently, pairing gap functions have topologically protected nodal structure as vortices in the momentum space with the total vorticity solely determined by the pair monopole charge qp. The nodes of gap function behave as the Weyl-Majorana points of the Bogoliubov-de Gennes pairing Hamiltonian. Their relation with the connection patterns of the surface modes from the Weyl band structure and the Majorana surface modes inside the pairing gap is also discussed. Under the approximation of spherical Fermi surfaces, the pairing symmetry are represented by monopole harmonic functions. The lowest possible pairing channel carries angular momentum number j =|qp|, and the corresponding gap functions are holomorphic or antiholomorphic functions on Fermi surfaces. After projected on the Fermi surfaces with nontrivial topology, all the partial-wave channels of pairing interactions acquire the monopole charge qp independent of concrete pairing mechanism.

Kramers Pairs in configuration interaction

DEFF Research Database (Denmark)

Avery, John Scales; Avery, James Emil

2003-01-01

The theory of symmetry-preserving Kramers pair creation operators is reviewed and formulas for applying these operators to configuration interaction calculations are derived. A new and more general type of symmetry-preserving pair creation operator is proposed and shown to commute with the total ...

Detection of no-model input-output pairs in closed-loop systems.

Science.gov (United States)

Potts, Alain Segundo; Alvarado, Christiam Segundo Morales; Garcia, Claudio

2017-11-01

The detection of no-model input-output (IO) pairs is important because it can speed up the multivariable system identification process, since all the pairs with null transfer functions are previously discarded and it can also improve the identified model quality, thus improving the performance of model based controllers. In the available literature, the methods focus just on the open-loop case, since in this case there is not the effect of the controller forcing the main diagonal in the transfer matrix to one and all the other terms to zero. In this paper, a modification of a previous method able to detect no-model IO pairs in open-loop systems is presented, but adapted to perform this duty in closed-loop systems. Tests are performed by using the traditional methods and the proposed one to show its effectiveness. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Effects of Single Leafy Spices on Growth and Carcass ...

African Journals Online (AJOL)

The dietary treatments consisted of a control (basal diet), basal diet + 10g basil leaf meal-BLM/kg diet, basal diet + 10g Heinsia leaf meal-HLM/kg diet and basal diet + 10g Piper leaf meal-PLM/kg diet. Fresh feed and water were offered daily ad libitum. Body weight gain, feed intake and feed efficiency were determined ...

Think Pair Share: A Teaching Learning Strategy to Enhance Students' Critical Thinking

Science.gov (United States)

Kaddoura, Mahmoud

2013-01-01

This study investigated the change in critical thinking (CT) skills of baccalaureate nursing students who were educated using a Think-Pair-Share (TPS) or an equivalent Non-Think-Pair-Share (Non-TPS) teaching method. Critical thinking has been an essential outcome of nursing students to prepare them to provide effective and safe quality care for…

Finding Maximal Pairs with Bounded Gap

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Lyngsø, Rune B.; Pedersen, Christian N. S.

1999-01-01

. In this paper we present methods for finding all maximal pairs under various constraints on the gap. In a string of length n we can find all maximal pairs with gap in an upper and lower bounded interval in time O(n log n+z) where z is the number of reported pairs. If the upper bound is removed the time reduces...... to O(n+z). Since a tandem repeat is a pair where the gap is zero, our methods can be seen as a generalization of finding tandem repeats. The running time of our methods equals the running time of well known methods for finding tandem repeats....

Relativistic description of pair production of doubly heavy baryons in e+e− annihilation

International Nuclear Information System (INIS)

Martynenko, A. P.; Trunin, A. M.

2015-01-01

Relativistic corrections in the pair production of S-wave doubly heavy diquarks in electron-positron annihilation were calculated on the basis of perturbative QCD and the quark model. The relativistic corrections to the wave functions for quark bound states were taken into account with the aid of the Breit potential in QCD. Relativistic effects change substantially the nonrelativistic cross sections for pair diquark production. The yield of pairs of (ccq) doubly heavy baryons at B factories was estimated

Facial expressions and pair bonds in hylobatids.

Science.gov (United States)

Florkiewicz, Brittany; Skollar, Gabriella; Reichard, Ulrich H

2018-06-06

, or rates of behavioral synchrony. We found that FES was the strongest measure of hylobatid expressiveness and was significantly positively correlated with higher sociality index scores; however, FES showed no significant correlation with behavioral synchrony. No noticeable differences between pairs were found regarding rates of behavioral or territorial synchrony. Facial repertoire sizes and FES were not significantly correlated with rates of behavioral synchrony or territorial synchrony. Our study confirms an important role of facial expressions in maintaining pair bonds and coordinating activities in hylobatids. Data support the hypothesis that facial expressions and sociality have been linked in hylobatid and primate evolution. It is possible that larger facial repertoires may have contributed to strengthening pair bonds in primates, because richer facial repertoires provide more opportunities for FES which can effectively increase the "understanding" between partners through smoother coordination of interaction patterns. This study supports the social complexity hypothesis as the driving force for the evolution of complex communication signaling. © 2018 Wiley Periodicals, Inc.

Pairing from dynamically screened Coulomb repulsion in bismuth

Science.gov (United States)

Ruhman, Jonathan; Lee, Patrick A.

2017-12-01

Recently, Prakash et al. have discovered bulk superconductivity in single crystals of bismuth, which is a semimetal with extremely low carrier density. At such low density, we argue that conventional electron-phonon coupling is too weak to be responsible for the binding of electrons into Cooper pairs. We study a dynamically screened Coulomb interaction with effective attraction generated on the scale of the collective plasma modes. We model the electronic states in bismuth to include three Dirac pockets with high velocity and one hole pocket with a significantly smaller velocity. We find a weak-coupling instability, which is greatly enhanced by the presence of the hole pocket. Therefore we argue that bismuth is the first material to exhibit superconductivity driven by retardation effects of Coulomb repulsion alone. By using realistic parameters for bismuth we find that the acoustic plasma mode does not play the central role in pairing. We also discuss a matrix element effect, resulting from the Dirac nature of the conduction band, which may affect Tc in the s -wave channel without breaking time-reversal symmetry.

Surface Andreev Bound States and Odd-Frequency Pairing in Topological Superconductor Junctions

Science.gov (United States)

Tanaka, Yukio; Tamura, Shun

2018-04-01

In this review, we summarize the achievement of the physics of surface Andreev bound states (SABS) up to now. The route of this activity has started from the physics of SABS of unconventional superconductors where the pair potential has a sign change on the Fermi surface. It has been established that SABS can be regarded as a topological edge state with topological invariant defined in the bulk Hamiltonian. On the other hand, SABS accompanies odd-frequency pairing like spin-triplet s-wave or spin-singlet p-wave. In a spin-triplet superconductor junction, induced odd-frequency pairing can penetrate into a diffusive normal metal (DN) attached to the superconductor. It causes so called anomalous proximity effect where the local density of states of quasiparticle in DN has a zero energy peak. When bulk pairing symmetry is spin-triplet px-wave, the anomalous proximity effect becomes prominent and the zero bias voltage conductance is always quantized independent of the resistance in DN and interface. Finally, we show that the present anomalous proximity effect is realized in an artificial topological superconducting system, where a nanowire with spin-orbit coupling and Zeeman field is put on the conventional spin-singlet s-wave superconductor.

A process-based approach to characterizing the effect of acute alprazolam challenge on visual paired associate learning and memory in healthy older adults.

Science.gov (United States)

Pietrzak, Robert H; Scott, James Cobb; Harel, Brian T; Lim, Yen Ying; Snyder, Peter J; Maruff, Paul

2012-11-01

Alprazolam is a benzodiazepine that, when administered acutely, results in impairments in several aspects of cognition, including attention, learning, and memory. However, the profile (i.e., component processes) that underlie alprazolam-related decrements in visual paired associate learning has not been fully explored. In this double-blind, placebo-controlled, randomized cross-over study of healthy older adults, we used a novel, "process-based" computerized measure of visual paired associate learning to examine the effect of a single, acute 1-mg dose of alprazolam on component processes of visual paired associate learning and memory. Acute alprazolam challenge was associated with a large magnitude reduction in visual paired associate learning and memory performance (d = 1.05). Process-based analyses revealed significant increases in distractor, exploratory, between-search, and within-search error types. Analyses of percentages of each error type suggested that, relative to placebo, alprazolam challenge resulted in a decrease in the percentage of exploratory errors and an increase in the percentage of distractor errors, both of which reflect memory processes. Results of this study suggest that acute alprazolam challenge decreases visual paired associate learning and memory performance by reducing the strength of the association between pattern and location, which may reflect a general breakdown in memory consolidation, with less evidence of reductions in executive processes (e.g., working memory) that facilitate visual paired associate learning and memory. Copyright © 2012 John Wiley & Sons, Ltd.

On friction of Nb-Nb pair in He1 and He2

International Nuclear Information System (INIS)

Zinenko, S.A.; Karapetyan, S.S.; Silin, A.A.

1990-01-01

Peculiarities of manifestation of the effect of anomalous friction of superconductors (AFS) in He1 and He2 are studied. Helium thermodynamic state effect on the character of friction interaction of Nb-Nb pair velocity and reduction ratio for friction coefficient is studied. The intensity of heat removal released from friction contact region is estimated, the necessary and sufficient conditions for AFC effect manifestation are ascertained using characteristic relaxation time concept. Dependences for Nb-Nb pair friction coefficient in a superconducting state on the time of friction interaction in gaseous helium, He1, He2 are presented

Pair breaking and charge relaxation in superconductors

International Nuclear Information System (INIS)

Nielson, J.B.; Pethick, C.J.; Rammer, J.; Smith, H.

1982-01-01

We present a general formalism based on the quasiclassical Green's function for calculating charge imbalance in nonequilibrium superconductors. Our discussion is sufficiently general that it applies at arbitrary temperatures, and under conditions when the width of quasiparticle states are appreciable due to pair breaking processes, and when strong coupling effects are significant. As a first application we demonstrate in detail how in the limit of smallpair breaking and for a weak coupling superconductor the collision term in the formalism reduces to the one in the quasiparticle Boltzmann equation. We next treat the case of charge imbalance generated by tunnel injection, with pair breaking by phonons and magnetic impurities. Over the range of temperatures investigated exerimentally to date, the calculated charge imbalance is rather close to that evaluated using the Boltzmann equation, even if pair braeking is so strong as almost to destroy superconductivity. Finally we consider charge imbalance generated by the combined influence of a supercurrent and a temperature gradient. We give calculations for a dirty superconductor with scattering by phonons as the pair breaking mechanism, and the results give a reasonable account of the experimental data of Clarke, Fjordboge, and Lindelof. We carry out calculations for the case of impurity scattering along which are valid not only in the clean and dirty limits, but also for intermediate situations. These enable us to see how the large contribution to the charge imbalance found for energies close to the gap edge in the clean case is reduced with increasing impurity scattering

Toward a Common Language for Measuring Patient Mobility in the Hospital: Reliability and Construct Validity of Interprofessional Mobility Measures.

Science.gov (United States)

Hoyer, Erik H; Young, Daniel L; Klein, Lisa M; Kreif, Julie; Shumock, Kara; Hiser, Stephanie; Friedman, Michael; Lavezza, Annette; Jette, Alan; Chan, Kitty S; Needham, Dale M

2018-02-01

The lack of common language among interprofessional inpatient clinical teams is an important barrier to achieving inpatient mobilization. In The Johns Hopkins Hospital, the Activity Measure for Post-Acute Care (AM-PAC) Inpatient Mobility Short Form (IMSF), also called "6-Clicks," and the Johns Hopkins Highest Level of Mobility (JH-HLM) are part of routine clinical practice. The measurement characteristics of these tools when used by both nurses and physical therapists for interprofessional communication or assessment are unknown. The purposes of this study were to evaluate the reliability and minimal detectable change of AM-PAC IMSF and JH-HLM when completed by nurses and physical therapists and to evaluate the construct validity of both measures when used by nurses. A prospective evaluation of a convenience sample was used. The test-retest reliability and the interrater reliability of AM-PAC IMSF and JH-HLM for inpatients in the neuroscience department (n = 118) of an academic medical center were evaluated. Each participant was independently scored twice by a team of 2 nurses and 1 physical therapist; a total of 4 physical therapists and 8 nurses participated in reliability testing. In a separate inpatient study protocol (n = 69), construct validity was evaluated via an assessment of convergent validity with other measures of function (grip strength, Katz Activities of Daily Living Scale, 2-minute walk test, 5-times sit-to-stand test) used by 5 nurses. The test-retest reliability values (intraclass correlation coefficients) for physical therapists and nurses were 0.91 and 0.97, respectively, for AM-PAC IMSF and 0.94 and 0.95, respectively, for JH-HLM. The interrater reliability values (intraclass correlation coefficients) between physical therapists and nurses were 0.96 for AM-PAC IMSF and 0.99 for JH-HLM. Construct validity (Spearman correlations) ranged from 0.25 between JH-HLM and right-hand grip strength to 0.80 between AM-PAC IMSF and the Katz Activities of

Leptoquark pair production in hadronic interactions

International Nuclear Information System (INIS)

Bluemlein, J.; Boos, E.; Moskovskij Gosudarstvennyj Univ., Moscow; Kryukov, A.; Moskovskij Gosudarstvennyj Univ., Moscow

1996-10-01

The scalar and vector leptoquark pair production cross sections in hadronic collisions are calculated. In a model independent analysis we consider the most general C and P conserving couplings of gluons to both scalar and vector leptoquarks described by an effective low-energy Lagangian which obeys SU(3) c invariance. Analytrical expressions are derived for the differential and integral scattering cross sections including the case of anomalous vector leptoquark couplings, κ G and λ G , to the gluon field. Numerical predictions are given for the kinematic range of the TEVATRON and LHC. The pair production cross sections are also calculated for the resolved photon contributions to ep → e anti ΦΦX at HERA and LEP x LHC, and for the process γγ → Φ anti ΦX at possible future e + e - linear colliders and γγ colliders. Estimates of the search potential for scalar and vector leptoquarks at present and future high energy colliders are given. (orig.)

Strong pairing approximation in comparison with the exact solutions to the pairing Hamiltonian

Directory of Open Access Journals (Sweden)

Lunyov A.V.

2016-01-01

Full Text Available 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.

Associated heavy quarks pair production with Higgs as a tool for a search for non-perturbative effects of the electroweak interaction at the LHC

Directory of Open Access Journals (Sweden)

B.A. Arbuzov

2017-09-01

Full Text Available Assuming an existence of the anomalous triple electro-weak bosons interaction being defined by coupling constant λ we calculate its contribution to interactions of the Higgs with pairs of heavy particles. Bearing in mind experimental restrictions −0.011<λ<0.011 we present results for possible effects in processes pp→W+W−H,pp→W+ZH,pp→W−ZH,pp→t¯tH, pp→b¯bH. Effects could be significant with negative sign of λ in associated heavy quarks t,b pairs production with the Higgs. In calculations we rely on results of the non-perturbative approach to a spontaneous generation of effective interactions, which defines the form-factor of the three-boson anomalous interaction.

Kπ=1+ pairing interaction and moments of inertia of superdeformed rotational bands in atomic nuclei

International Nuclear Information System (INIS)

Hamamoto, I.; Nazarewicz, W.

1994-01-01

The effect of the pairing interaction coming from the rotationally induced K π =1 + pair-density on the nuclear moments of inertia is studied. It is pointed out that, contrary to the situation at normal deformations, the inclusion of the K π =1 + pairing may appreciably modify the frequency dependence of the moments of inertia at superdeformed shapes

Junctionless Cooper pair transistor

Energy Technology Data Exchange (ETDEWEB)

Arutyunov, K. Yu., E-mail: konstantin.yu.arutyunov@jyu.fi [National Research University Higher School of Economics , Moscow Institute of Electronics and Mathematics, 101000 Moscow (Russian Federation); P.L. Kapitza Institute for Physical Problems RAS , Moscow 119334 (Russian Federation); Lehtinen, J.S. [VTT Technical Research Centre of Finland Ltd., Centre for Metrology MIKES, P.O. Box 1000, FI-02044 VTT (Finland)

2017-02-15

Highlights: • Junctionless Cooper pair box. • Quantum phase slips. • Coulomb blockade and gate modulation of the Coulomb gap. - Abstract: Quantum phase slip (QPS) is the topological singularity of the complex order parameter of a quasi-one-dimensional superconductor: momentary zeroing of the modulus and simultaneous 'slip' of the phase by ±2π. The QPS event(s) are the dynamic equivalent of tunneling through a conventional Josephson junction containing static in space and time weak link(s). Here we demonstrate the operation of a superconducting single electron transistor (Cooper pair transistor) without any tunnel junctions. Instead a pair of thin superconducting titanium wires in QPS regime was used. The current–voltage characteristics demonstrate the clear Coulomb blockade with magnitude of the Coulomb gap modulated by the gate potential. The Coulomb blockade disappears above the critical temperature, and at low temperatures can be suppressed by strong magnetic field.

The Effectiveness of Cooperative Learning Model of Pair Checks Type on Motivation and Mathematics Learning Outcomes of 8th Grade Junior High School Students

Directory of Open Access Journals (Sweden)

Wahyu Budi Wicaksono

2017-08-01

Full Text Available The purpose of this research was to know the effectiveness of Pair Checks cooperative model towards students’ learning result and learning motivation of eight grade. Population of this research were students of eight grade Junior High School 2 Pati in the academic year 2016/1017. The research used cluster random sampling technique.Where the selected samples were students of class VIII H as experimental class and class VIII G as control class. The data collected by the method of documentation, test methods, and scale methods. The analyzed of data used completeness test and average different test. The results showed that: (1 students’ learning result who join Pair Checks cooperative model have classical study completeness; (2 students’ mathematics learning result who join Pair Checks cooperative model is better than students mathematics learning result who join ekspository learning; (3 students’ learning motivation who join Pair Checks cooperative model is better than students’ learning motivation who join ekspository learning.

Early pair housing increases solid feed intake and weight gains in dairy calves.

Science.gov (United States)

Costa, J H C; Meagher, R K; von Keyserlingk, M A G; Weary, D M

2015-09-01

Dairy calves have traditionally been kept in individual pens throughout the milk-feeding period. Social rearing is associated with increased solid feed intake and, hence, higher weight gains before and after weaning. Little is known about the effect of the age at which social housing begins. The aim of this study was to assess the effects of early versus late pairing on feeding behavior and weight gain before and after weaning. Holstein bull calves were reared individually (n=8 calves) or paired with another calf at 6±3 d (n=8 pairs) or 43±3 d of age (n=8 pairs). All calves were fed 8 L of milk/d for 4 wk, 6 L/d from 4 to 7 wk, and then milk was reduced by 20%/d until calves were completely weaned at 8 wk of age. Calves were provided ad libitumaccess to calf starter and a total mixed ration (TMR). Body weight and feed intake were measured weekly from 3 to 10 wk of age.Intake of calf starter was significantly higher for the early-paired calves than for individually reared and late-paired calves throughout the experimental period. At 10 wk of age, starter dry matter intake averaged 2.20±0.22, 1.09±0.25, and 1.26±0.33kg/d for early-paired, late-paired, and individually housed calves, respectively. Intake of TMR did not differ among treatments, TMR dry matter intake averaged 3.27±0.72, 3.08±0.46, and 2.89±0.54kg/d for the same 3 treatments. Calves in the early paired treatment also showed significantly higher average daily gain over the experimental period (0.89±0.04 vs. 0.76±0.04 and 0.73±0.04kg/d for the early-paired, individual, and late-paired calves, respectively). These results indicate that social housing soon after birth can increase weight gains and intake of solid feed. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Nuclear squid: Diabolic pair transfer in rotating nuclei

Energy Technology Data Exchange (ETDEWEB)

Nikam, R S; Ring, P; Canto, L F

1987-02-19

A new unexpected behavior of pair transfer matrix elements in superfluid rotating nuclei is predicted. With increasing angular velocity they drop to zero, change their sign and in some cases even oscillate between positive and negative values. This effect is related to diabolical points in rotating quasiparticle spectra and is closely analogous to the DC-Josephson effect in superconductors in the presence of a magnetic field.

Pair breaking and density of states in disordered superconductors

International Nuclear Information System (INIS)

Weinkauf, A.; Zittartz, J.

1975-01-01

It is shown that pair breaking occurs in a disordered superconductor due to spatial variations of the order parameter, although the system is time reversal invariant. The pair breaking effect is reflected by the occurence of some interesting fine structure in the one particle density of states. Discrete bound states and split-off impurity bands show up in the single impurity case and for very dilute alloys, respectively. For finite alloy concentrations the calculations are done within the CPA. Although principally important, the fine structure is concentrated in an energy range too narrow to be detected experimentally. (orig.) [de

Higgs pair production at NLO QCD for CP-violating Higgs sectors

Directory of Open Access Journals (Sweden)

R. Gröber

2017-12-01

Full Text Available Higgs pair production through gluon fusion is an important process at the LHC to test the dynamics underlying electroweak symmetry breaking. Higgs sectors beyond the Standard Model (SM can substantially modify this cross section through novel couplings not present in the SM or the on-shell production of new heavy Higgs bosons that subsequently decay into Higgs pairs. CP violation in the Higgs sector is important for the explanation of the observed matter-antimatter asymmetry through electroweak baryogenesis. In this work we compute the next-to-leading order (NLO QCD corrections in the heavy top quark limit, including the effects of CP violation in the Higgs sector. We choose the effective theory (EFT approach, which provides a rather model-independent way to explore New Physics (NP effects by adding dimension-6 operators, both CP-conserving and CP-violating ones, to the SM Lagrangian. Furthermore, we perform the computation within a specific UV-complete model and choose as benchmark model the general 2-Higgs-Doublet Model with CP violation, the C2HDM. Depending on the dimension-6 coefficients, the relative NLO QCD corrections are affected by several per cent through the new CP-violating operators. This is also the case for SM-like Higgs pair production in the C2HDM, while the relative QCD corrections in the production of heavier C2HDM Higgs boson pairs deviate more strongly from the SM case. The absolute cross sections both in the EFT and the C2HDM can be modified by more than an order of magnitude. In particular, in the C2HDM the resonant production of Higgs pairs can by far exceed the SM cross section.

PAIR'14 / PAIR'15 STUDENT CONFERENCES ON PLANNING IN ARTIFICIAL INTELLIGENCE AND ROBOTICS

Directory of Open Access Journals (Sweden)

Editorial Foreword

2015-12-01

Full Text Available Dear Readerthe original idea of the student conference on “Planning in Artificial Intelligence and Robotics” (PAIR is to join young researchers from particular laboratories in Czech Republic, where planning problems are investigated from artificial intelligence (AI or robotics points of view. The first year of PAIR has been organized at the Dept. of Computer Science, Faculty Electrical Engineering, Czech Technical University in 2014.At PAIR 2014, laboratories from Prague and Brno were presented. In particular, students and researchers from Charles University, Czech Technical University in Prague, Brno University of Technology, and Central European Institute of Technology participated at the event. Beside an introduction of the particular research groups and their topics, students presented contributions on their current research results. Ten papers were presented on topics ranging from domain–independent planning, trajectory planning to applications for unmanned aerial and legged robots. This first event provides us an initial experience with the community of young researchers in Czech Republic that are working planning in robotic or AI. Based on the success of PAIR 2014, we decided to continue with our effort to establish a suitable fora for students that are geographically very close, but usually do not meet, because of participation on different Robotics and AI events.The second student conference on Planning in Artificial Intelligence and Robotics (PAIR 2015 successfully continues the tradition of the first year of the conference organized in Prague. This year, the conference was collocated with 10th anniversary of RoboTour contest in Písek. This format enable us to extend the impact of the PAIR conference and improve the visibility of the growing student community. The conference reached a good amount of interesting papers focused on image processing for mobile robots, swarm control, driving simulation, robot control, or domain�

Inhibition of the human liver microsomal and human cytochrome P450 1A2 and 3A4 metabolism of estradiol by deployment-related and other chemicals.

Science.gov (United States)

Usmani, Khawja A; Cho, Taehyeon M; Rose, Randy L; Hodgson, Ernest

2006-09-01

Cytochromes P450 (P450s) are major catalysts in the metabolism of xenobiotics and endogenous substrates such as estradiol (E2). It has previously been shown that E2 is predominantly metabolized in humans by CYP1A2 and CYP3A4 with 2-hydroxyestradiol (2-OHE2) the major metabolite. This study examines effects of deployment-related and other chemicals on E2 metabolism by human liver microsomes (HLM) and individual P450 isoforms. Kinetic studies using HLM, CYP3A4, and CYP1A2 showed similar affinities (Km) for E2 with respect to 2-OHE2 production. Vmax and CLint values for HLM are 0.32 nmol/min/mg protein and 7.5 microl/min/mg protein; those for CYP3A4 are 6.9 nmol/min/nmol P450 and 291 microl/min/nmol P450; and those for CYP1A2 are 17.4 nmol/min/nmol P450 and 633 microl/min/nmol P450. Phenotyped HLM use showed that individuals with high levels of CYP1A2 and CYP3A4 have the greatest potential to metabolize E2. Preincubation of HLM with a variety of chemicals, including those used in military deployments, resulted in varying levels of inhibition of E2 metabolism. The greatest inhibition was observed with organophosphorus compounds, including chlorpyrifos and fonofos, with up to 80% inhibition for 2-OHE2 production. Carbaryl, a carbamate pesticide, and naphthalene, a jet fuel component, inhibited ca. 40% of E2 metabolism. Preincubation of CYP1A2 with chlorpyrifos, fonofos, carbaryl, or naphthalene resulted in 96, 59, 84, and 87% inhibition of E2 metabolism, respectively. Preincubation of CYP3A4 with chlorpyrifos, fonofos, deltamethrin, or permethrin resulted in 94, 87, 58, and 37% inhibition of E2 metabolism. Chlorpyrifos inhibition of E2 metabolism is shown to be irreversible.

Aerodynamic Interactions between Pairs of Vertical-Axis Wind Turbines

Science.gov (United States)

Brownstein, Ian; Dabiri, John

2017-11-01

Increased power production has been observed in downstream vertical-axis wind turbines (VAWTs) when positioned offset from the wake of upstream turbines. This effect was found to exist in both laboratory and field environments with pairs of co- and counter-rotating turbines. It is hypothesized that the observed power production enhancement is due to flow acceleration adjacent to the upstream turbine caused by bluff body blockage, which increases the incident freestream velocity on appropriately positioned downstream turbines. This type of flow acceleration has been observed in computational and laboratory studies of VAWTs and will be further investigated here using 3D-PTV measurements around pairs of laboratory-scale VAWTs. These measurements will be used to understand the mechanisms behind the performance enhancement effect and seek to determine optimal separation distances and angles between turbines based on turbine design parameters. These results will lead to recommendations for optimizing the power production of VAWT wind farms which utilize this effect.

Time- and Space-Order Effects in Timed Discrimination of Brightness and Size of Paired Visual Stimuli

Science.gov (United States)

Patching, Geoffrey R.; Englund, Mats P.; Hellstrom, Ake

2012-01-01

Despite the importance of both response probability and response time for testing models of choice, there is a dearth of chronometric studies examining systematic asymmetries that occur over time- and space-orders in the method of paired comparisons. In this study, systematic asymmetries in discriminating the magnitude of paired visual stimuli are…

A pure Hubbard model with demonstrable pairing adjacent to the Mott-insulating phase

International Nuclear Information System (INIS)

Champion, J D; Long, M W

2003-01-01

We introduce a Hubbard model on a particular class of geometries, and consider the effect of doping the highly spin-degenerate Mott-insulating state with a microscopic number of holes in the extreme strong-coupling limit. The geometry is quite general, with pairs of atomic sites at each superlattice vertex, and a highly frustrated inter-atomic connectivity: the one-dimensional realization is a chain of edge-sharing tetrahedra. The sole model parameter is the ratio of intra-pair to inter-pair hopping matrix elements. If the intra-pair hopping is negligible then introducing a microscopic number of holes results in a ferromagnetic Nagaoka groundstate. Conversely, if the intra-pair hopping is comparable with the inter-pair hopping then the groundstate is low spin with short-ranged spin correlations. We exactly solve the correlated motion of a pair of holes in such a state and find that, in 1d and 2d, they form a bound pair on a length scale that increases with diminishing binding energy. This result is pertinent to the long-standing problem of hole motion in the CuO 2 planes of the high-temperature superconductors: we have rigorously shown that, on our frustrated geometry, the holes pair up and a short-ranged low-spin state is generated by hole motion alone

Exploring Pair Programming Benefits for MIS Majors

Directory of Open Access Journals (Sweden)

April H. Reed

2016-12-01

Full Text Available Pair programming is a collaborative programming practice that places participants in dyads, working in tandem at one computer to complete programming assignments. Pair programming studies with Computer Science (CS and Software Engineering (SE majors have identified benefits such as technical productivity, program/design quality, academic performance, and increased satisfaction for their participants. In this paper, pair programming is studied with Management Information Systems (MIS majors, who (unlike CS and SE majors taking several programming courses typically take only one programming course and often struggle to develop advanced programming skills within that single course. The researchers conducted two pair programming experiments in an introductory software development course for MIS majors over three semesters to determine if pair programming could enhance learning for MIS students. The program results, researchers’ direct observations, and participants’ responses to a survey questionnaire were analyzed after each experiment. The results indicate that pair programming appears to be beneficial to MIS students’ technical productivity and program design quality, specifically the ability to create programs using high-level concepts. Additionally, results confirmed increased student satisfaction and reduced frustration, as the pairs worked collaboratively to produce a program while actively communicating and enjoying the process.

Strong quasi-particle tunneling study in the paired quantum Hall states

OpenAIRE

Nomura, Kentaro; Yoshioka, Daijiro

2001-01-01

The quasi-particle tunneling phenomena in the paired fractional quantum Hall states are studied. A single point-contact system is first considered. Because of relevancy of the quasi-particle tunneling term, the strong tunneling regime should be investigated. Using the instanton method it is shown that the strong quasi-particle tunneling regime is described as the weak electron tunneling regime effectively. Expanding to the network model the paired quantum Hall liquid to insulator transition i...

An experimental study of the effect of external turbulence on the decay of a single vortex and a vortex pair

NARCIS (Netherlands)

van Jaarsveld, J.P.J.; Holten, A.P.C.; Elsenaar, A.; Trieling, R.R.; Heijst, van G.J.F.

2011-01-01

This study is concerned with the effect of external turbulence on the decay of vortices. Single vortices and vortex pairs were generated with wing(s) mounted in the sidewalls of a wind tunnel. The distance between the two vortices could be adjusted such that they just touched each other or

The Effects of the Paired Associates Strategy (PAS) on the Recall of Factual Information by Postsecondary Students with Learning Disabilities

Science.gov (United States)

Patwa, Shamim S.; Chafouleas, Sandra M.; Madaus, Joseph W.

2005-01-01

Despite the success of independence-oriented interventions such as strategy instruction (SI) in secondary populations, very little research has examined the effectiveness of SI at the postsecondary level. Thus, we sought to determine if one form of SI, the Paired Associates Strategy (PAS), improved the recall of factual information by…

Efficient genome editing by FACS enrichment of paired D10A Cas9 nickases coupled with fluorescent proteins.

Science.gov (United States)

Gopalappa, Ramu; Song, Myungjae; Chandrasekaran, Arun Pandian; Das, Soumyadip; Haq, Saba; Koh, Hyun Chul; Ramakrishna, Suresh

2018-05-31

Targeted genome editing by clustered regularly interspaced short palindromic repeats (CRISPR-Cas9) raised concerns over off-target effects. The use of double-nicking strategy using paired Cas9 nickase has been developed to minimize off-target effects. However, it was reported that the efficiency of paired nickases were comparable or lower than that of either corresponding nuclease alone. Recently, we conducted a systematic comparison of the efficiencies of several paired Cas9 with their corresponding Cas9 nucleases and showed that paired D10A Cas9 nickases are sometimes more efficient than individual nucleases for gene disruption. However, sometimes the designed paired Cas9 nickases exhibited significantly lower mutation frequencies than nucleases, hampering the generation of cells containing paired Cas9 nickase-induced mutations. Here we implemented IRES peptide-conjugation of fluorescent protein to Cas9 nickase and subjected for fluorescence-activated cell sorting. The sorted cell populations are highly enriched with cells containing paired Cas9 nickase-induced mutations, by a factor of up to 40-fold as compared with the unsorted population. Furthermore, gene-disrupted single cell clones using paired nickases followed by FACS sorting strategy were generated highly efficiently, without compromising with its low off-target effects. We envision that our fluorescent protein coupled paired nickase-mediated gene disruption, facilitating efficient and highly specific genome editing in medical research.

VLBA Reveals Closest Pair of Supermassive Black Holes

Science.gov (United States)

2006-05-01

black holes," Taylor said. The VLBA is a continent-wide system of ten radio-telescope antennas. It provides the greatest ability to see fine detail, called resolving power, of any telescope in astronomy. "Astronomers have thought for a long time that close pairs of black holes should result from galaxy collisions," Rodriguez said. Still, finding them has proven difficult. Until now, the closest confirmed pairs of supermassive black holes were at least 4,500 light-years apart. Pairs of smaller black holes, each only a few times the mass of the Sun, have been found in our own Milky Way Galaxy, but 0402+379 harbors the pair of supermassive black holes that are the closest to each other yet found. Galactic collisions are common throughout the Universe, and astronomers think that the binary pairs of supermassive black holes that result can have important effects on the subsequent evolution of the galaxies. In a number of predicted scenarios, such giant pairs of black holes will themselves collide, sending gravitational waves out through the Universe. Such gravitational waves could be detected with a proposed joint space mission between NASA and the European Space Agency, the Laser Interferometer Space Antenna. "Such black-hole collisions undoubtedly are important processes, and we need to understand them. Finding ever-closer pairs of supermassive black holes is the first step in that process. Even finding one such system has dramatically changed our expectations, and informed us about what to look for," Taylor said. Taylor and his collaborators are currently using the VLBA to carry out the largest survey of compact radio-emitting objects ever undertaken, in the hope of finding more such pairs. Rodriguez and Taylor worked with Robert Zavala of the U.S. Naval Observatory, Allison Peck of the SubMillimeter Array of the Harvard- Smithsonian Center for Astrophysics, Lindsey Pollack of the University of California at Santa Cruz, and Roger Romani of Stanford University. Their

Photon propagator and pair production in stationary electric field

International Nuclear Information System (INIS)

Makhlin, A.N.; Olejnik, V.P.

1978-01-01

Effects related to pair production by an external field are discussed. It is shown that vacuum instability against pair production leads to an essential difference between the propagator and Feynman Green's function. Analysis of Yang-Feldman equations and of boundary conditions imposed upon the Green's function shows that using Feynman Green's function as a propagator contradicts the causality principle. The physical causality principle is satisfied by Heisenberg Green's function for which usual Schwinger-Dyson equations cannot be formulated. Heisenberg and Feynman Green's functions coincide for the case of stable vacuum state. All calculations are carried out using the technique of the so-called generalized Green's functions in terms of which the propagators are written. The polarization operator in the electric field is calculated in the one-loop approximation. Its' general structure is found. The photon propagator is obtained. Self oscillations of the photon vacuum are determined. It is shown that new modes correspond to collective excitations of the type ''photon+electron-positron pairs''

Nuclear scissors mode with pairing

International Nuclear Information System (INIS)

Balbutsev, E. B.; Malov, L. A.; Schuck, P.; Urban, M.; Vinas, X.

2008-01-01

The coupled dynamics of the scissors mode and the isovector giant quadrupole resonance are studied using a generalized Wigner function moments method, taking into account pair correlations. Equations of motion for angular momentum, quadrupole moment, and other relevant collective variables are derived on the basis of the time-dependent Hartree-Fock-Bogolyubov equations. Analytical expressions for energy centroids and transition probabilities are found for the harmonic-oscillator model with the quadrupole-quadrupole residual interaction and monopole pairing force. Deformation dependences of energies and B(M1) values are correctly reproduced. The inclusion of pair correlations leads to a drastic improvement in the description of qualitative and quantitative characteristics of the scissors mode.

Electronic pairing mechanism due to band modification with increasing pair number

International Nuclear Information System (INIS)

Mizia, J.

1995-01-01

It is shown that a shift of an electron band with electron occupation number n, which is changing during the transition to the superconducting state, can lower the total energy of the system. In fact it will bring a negative contribution to the pairing potential, which is proportional to the product of the electron band shift with occupation number and the charge transfer during the transition to the superconducting state. The shift of the electron band comes from the change of stresses and the change of correlation effects in the CuO 2 plane with n, that in turn is caused by the changing oxygen concentration. This model explains the phenomenological success of Hirsch's model, which gives no explanation how the band shift in energy can give rise to superconductivity. (orig.)

Test of s-wave pairing in heavy-fermion systems due to Kondo volume collapse

International Nuclear Information System (INIS)

Svozil, K.

1987-01-01

It is proposed to utilize resonant Raman scattering on heavy-fermion superconductors as a test for Cooper pairing via an effective phonon-mediated attraction due to the Kondo volume collapse. The suggested experiment might help to discriminate between singlet and triplet pairing

Neutron matter, neutron pairing, and neutron drops based on chiral effective field theory interactions

Energy Technology Data Exchange (ETDEWEB)

Krueger, Thomas

2016-10-19

The physics of neutron-rich systems is of great interest in nuclear and astrophysics. Precise knowledge of the properties of neutron-rich nuclei is crucial for understanding the synthesis of heavy elements. Infinite neutron matter determines properties of neutron stars, a final stage of heavy stars after a core-collapse supernova. It also provides a unique theoretical laboratory for nuclear forces. Strong interactions are determined by quantum chromodynamics (QCD). However, QCD is non-perturbative at low energies and one presently cannot directly calculate nuclear forces from it. Chiral effective field theory circumvents these problems and connects the symmetries of QCD to nuclear interactions. It naturally and systematically includes many-nucleon forces and gives access to uncertainty estimates. We use chiral interactions throughout all calculation in this thesis. Neutron stars are very extreme objects. The densities in their interior greatly exceed those in nuclei. The exact composition and properties of neutron stars is still unclear but they consist mainly of neutrons. One can explore neutron stars theoretically with calculations of neutron matter. In the inner core of neutron stars exist very high densities and thus maybe exotic phases of matter. To investigate whether there exists a phase transition to such phases even at moderate densities we study the chiral condensate in neutron matter, the order parameter of chiral symmetry breaking, and find no evidence for a phase transition at nuclear densities. We also calculate the more extreme system of spin-polarised neutron matter. With this we address the question whether there exists such a polarised phase in neutron stars and also provide a benchmark system for lattice QCD. We find spin-polarised neutron matter to be an almost non-interacting Fermi gas. To understand the cooling of neutron stars neutron pairing is of great importance. Due to the high densities especially triplet pairing is of interest. We

Theoretical Treatment of Degenerate Electron Exchange and Dimerization in Spin Dynamics of Radical Ion Pairs as Observed by Magnetic Field Effects

NARCIS (Netherlands)

Ivanov, K.L.; Stass, D.V.; Kalneus, E.V.; Kaptein, R.; Lukzen, N.K.

2013-01-01

In this work we have compared manifestations of degenerate electron exchange (DEE) and dimerization reactions in MARY (magnetically affected reaction yield) spectroscopy and time-resolved magnetic field effects (TR-MFE) of radical ion pairs (RIPs). It is shown that dimerization results in phase and

The pair potential approach for interfaces: Fundamental problems and practical solutions

International Nuclear Information System (INIS)

Maggs, A.C.; Ashcroft, N.W.

1987-09-01

A fundamental problem in the use of a central pair-force model for defect problems is that it omits three-body and higher terms which are necessarily present in real systems. Electronic fluctuation effects are also usually omitted. While these can be small in the simple metals, they are significant in noble and transition metals, as shown by a simple real space argument. To guage the importance of their effects in interface problems, the structure of a simple sum 5 twist boundary is examined, with the atoms described by both pair- and three-center interactions and as a function of the relative strength of the two. 15 refs

An Entropic Approach for Pair Trading

Directory of Open Access Journals (Sweden)

Daisuke Yoshikawa

2017-06-01

Full Text Available In this paper, we derive the optimal boundary for pair trading. This boundary defines the points of entry into or exit from the market for a given stock pair. However, if the assumed model contains uncertainty, the resulting boundary could result in large losses. To avoid this, we develop a more robust strategy by accounting for the model uncertainty. To incorporate the model uncertainty, we use the relative entropy as a penalty function in the expected profit from pair trading.

Reduction of nuclear moment of inertia due to pairing interaction

International Nuclear Information System (INIS)

Zeng, J.Y.; Jin, T.H.; Zhao, Z.J.

1994-01-01

The BCS theoretical values of the moments of inertia of even-even nuclei are systematically smaller than the experimental ones by a factor of 10--40%. This long-standing discrepancy disappears in the particle-number-conserving treatment for the cranked shell model, in which the blocking effects are taken into account exactly. The calculated moments of inertia satisfactorily reproduce the experimental data covering a large number of rare-earth even-even nuclei, whose deformations and single-particle states are well characterized (Lund systematics). The pairing interaction strength G is unambiguously determined by the even-odd mass difference. The reduction of the moment of inertia due to the antialignment effect of pairing interaction is discussed and no systematic excessive reduction is found

Alexander-equivalent Zariski pairs of irreducible sextics

DEFF Research Database (Denmark)

Eyral, Christophe; Oka, Mutsuo

2009-01-01

The existence of Alexander-equivalent Zariski pairs dealing with irreducible curves of degree 6 was proved by Degtyarev. However, no explicit example of such a pair is available (only the existence is known) in the literature. In this paper, we construct the first concrete example.......The existence of Alexander-equivalent Zariski pairs dealing with irreducible curves of degree 6 was proved by Degtyarev. However, no explicit example of such a pair is available (only the existence is known) in the literature. In this paper, we construct the first concrete example....

Biophysical analysis of a lethal laminin alpha-1 mutation reveals altered self-interaction

KAUST Repository

Patel, Trushar R.; Nikodemus, Denise; Besong, Tabot M.D.; Reuten, Raphael; Meier, Markus; Harding, Stephen E.; Winzor, Donald J.; Koch, Manuel; Stetefeld, Jö rg

2015-01-01

Laminins are key basement membrane molecules that influence several biological activities and are linked to a number of diseases. They are secreted as heterotrimeric proteins consisting of one α, one β, and one γ chain, followed by their assembly into a polymer-like sheet at the basement membrane. Using sedimentation velocity, dynamic light scattering, and surface plasmon resonance experiments, we studied self-association of three laminin (LM) N-terminal fragments α-1 (hLM α-1 N), α-5 (hLM α-5 N) and β-3 (hLM β-3 N) originating from the short arms of the human laminin αβγ heterotrimer. Corresponding studies of the hLM α-1 N C49S mutant, equivalent to the larval lethal C56S mutant in zebrafish, have shown that this mutation causes enhanced self-association behavior, an observation that provides a plausible explanation for the inability of laminin bearing this mutation to fulfill functional roles in vivo, and hence for the deleterious pathological consequences of the mutation on lens function.

Biophysical analysis of a lethal laminin alpha-1 mutation reveals altered self-interaction

KAUST Repository

Patel, Trushar R.

2015-07-26

Laminins are key basement membrane molecules that influence several biological activities and are linked to a number of diseases. They are secreted as heterotrimeric proteins consisting of one α, one β, and one γ chain, followed by their assembly into a polymer-like sheet at the basement membrane. Using sedimentation velocity, dynamic light scattering, and surface plasmon resonance experiments, we studied self-association of three laminin (LM) N-terminal fragments α-1 (hLM α-1 N), α-5 (hLM α-5 N) and β-3 (hLM β-3 N) originating from the short arms of the human laminin αβγ heterotrimer. Corresponding studies of the hLM α-1 N C49S mutant, equivalent to the larval lethal C56S mutant in zebrafish, have shown that this mutation causes enhanced self-association behavior, an observation that provides a plausible explanation for the inability of laminin bearing this mutation to fulfill functional roles in vivo, and hence for the deleterious pathological consequences of the mutation on lens function.

Recent advances in mechanism-based chemotherapy drug-siRNA pairs in co-delivery systems for cancer: A review.

Science.gov (United States)

Wang, Mingfang; Wang, Jinyu; Li, Bingcheng; Meng, Lingxin; Tian, Zhaoxing

2017-09-01

Co-delivery of chemotherapy drugs and siRNA for cancer therapy has achieved remarkable results according to synergistic/combined antitumor effects, and is recognized as a promising therapeutic modality. However, little attention has been paid to the extremely complex mechanisms of chemotherapy drug-siRNA pairs during co-delivery process. Proper selection of chemotherapy drug-siRNA pairs is beneficial for achieving desirable cancer therapeutic effects. Exploring the inherent principles during chemotherapy drug-siRNA pair selection for co-delivery would greatly enhanced therapeutic efficiency. To achieve ideal results, this article will systematically review current different mechanism-based chemotherapy drug-siRNA pairs for co-delivery in cancer treatment. Large-scale library screening of recent different chemotherapy drug-siRNA pairs for co-delivery would help to establish the chemotherapy drug-siRNA pair selection principle, which could pave the way for co-delivery of chemotherapy drugs and siRNA for cancer treatment in clinic. Following the inherent principle of chemotherapy drug-siRNA pair, more effective co-delivery vectors can be designed in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

Proton-neutron correlations in a broken-pair model

International Nuclear Information System (INIS)

Akkermans, J.N.L.

1981-01-01

In this thesis nuclear-structure calculations are reported which were performed with the broken-pair model. The model which is developed, is an extension of existing broken-pair models in so far that it includes both proton and neutron valence pairs. The relevant formalisms are presented. In contrast to the number-non-conserving model, a proton-neutron broken-pair model is well suited to study the correlations which are produced by the proton-neutron interaction. It is shown that the proton-neutron force has large matrix elements which mix the proton- with neutron broken-pair configurations. This occurs especially for Jsup(PI)=2 + and 3 - pairs. This property of the proton-neutron force is used to improve the spectra of single-closed shell nuclei, where particle-hole excitations of the closed shell are a special case of broken-pair configurations. Using Kr and Te isotopes it is demonstrated that the proton-neutron force gives rise to correlated pair structures, which remain remarkably constant with varying nucleon numbers. (Auth.)

Thermodynamics of pairing phase transition in nuclei

International Nuclear Information System (INIS)

Karim, Afaque; Ahmad, Shakeb

2014-01-01

The pairing gaps, pairing energy, heat capacity and entropy are calculated within BCS (Bardeen- Cooper-Schrieffer) based quasi particle approach, including thermal fluctuations on pairing field within pairing model for all nuclei (light, medium, heavy and super heavy nuclei). Quasi particles approach in BCS theory was introduced and reformulated to study various properties. For thermodynamic behavior of nuclei at finite temperatures, the anomalous averages of creation and annihilation operators are introduced. It is solved self consistently at finite temperatures to obtain BCS Hamiltonian. After doing unitary transformation, we obtained the Hamiltonian in the diagonal form. Thus, one gets temperature dependence gap parameter and pairing energy for nuclei. Moreover, the energy at finite temperatures is the sum of the condensation energy and the thermal energy of fermionic quasi particles. With the help of BCS Hamiltonian, specific heat, entropy and free energy are calculated for different nuclei. In this paper the gap parameter occupation number and pairing energy as a function of temperature which is important for all the light, medium, heavy and super heavy nuclei is calculated. Moreover, the various thermo dynamical quantities like specific heat, entropy and free energy is also obtained for different nuclei. Thus, the thermodynamics of pairing phase transition in nuclei is studied

Chromosomal locations of members of a family of novel endogenous human retroviral genomes

International Nuclear Information System (INIS)

Horn, T.M.; Huebner, K.; Croce, C.; Callahan, R.

1986-01-01

Human cellular DNA contains two distinguishable families of retroviral related sequences. One family shares extensive nucleotide sequence homology with infectious mammalian type C retroviral genomes. The other family contains major regions of homology with the pol genes of infectious type A and B and avian type C and D retroviral genomes. Analysis of the human recombinant clone HLM-2 has shown that the pol gene in the latter family is located within an endogenous proviral genome. The authors show that the proviral genome in HLM-2 and the related recombinant clone HLM-25 are located, respectively, on human chromosomes 1 and 5. Other related proviral genomes are located on chromosomes 7, 8, 11, 14, and 17

Model for pairing phase transition in atomic nuclei

International Nuclear Information System (INIS)

Schiller, A.; Guttormsen, M.; Hjorth-Jensen, M.; Rekstad, J.; Siem, S.

2002-01-01

A model is developed which allows the investigation and classification of the pairing phase transition in atomic nuclei. The regions of the parameter space are discussed for which a pairing phase transition can be observed. The model parameters include number of particles, attenuation of pairing correlations with increasing seniority, single-particle level spacing, and pairing gap parameter

Differential stabilities and sequence-dependent base pair opening dynamics of Watson-Crick base pairs with 5-hydroxymethylcytosine, 5-formylcytosine, or 5-carboxylcytosine.

Science.gov (United States)

Szulik, Marta W; Pallan, Pradeep S; Nocek, Boguslaw; Voehler, Markus; Banerjee, Surajit; Brooks, Sonja; Joachimiak, Andrzej; Egli, Martin; Eichman, Brandt F; Stone, Michael P

2015-02-10

5-Hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) form during active demethylation of 5-methylcytosine (5mC) and are implicated in epigenetic regulation of the genome. They are differentially processed by thymine DNA glycosylase (TDG), an enzyme involved in active demethylation of 5mC. Three modified Dickerson-Drew dodecamer (DDD) sequences, amenable to crystallographic and spectroscopic analyses and containing the 5'-CG-3' sequence associated with genomic cytosine methylation, containing 5hmC, 5fC, or 5caC placed site-specifically into the 5'-T(8)X(9)G(10)-3' sequence of the DDD, were compared. The presence of 5caC at the X(9) base increased the stability of the DDD, whereas 5hmC or 5fC did not. Both 5hmC and 5fC increased imino proton exchange rates and calculated rate constants for base pair opening at the neighboring base pair A(5):T(8), whereas 5caC did not. At the oxidized base pair G(4):X(9), 5fC exhibited an increase in the imino proton exchange rate and the calculated kop. In all cases, minimal effects to imino proton exchange rates occurred at the neighboring base pair C(3):G(10). No evidence was observed for imino tautomerization, accompanied by wobble base pairing, for 5hmC, 5fC, or 5caC when positioned at base pair G(4):X(9); each favored Watson-Crick base pairing. However, both 5fC and 5caC exhibited intranucleobase hydrogen bonding between their formyl or carboxyl oxygens, respectively, and the adjacent cytosine N(4) exocyclic amines. The lesion-specific differences observed in the DDD may be implicated in recognition of 5hmC, 5fC, or 5caC in DNA by TDG. However, they do not correlate with differential excision of 5hmC, 5fC, or 5caC by TDG, which may be mediated by differences in transition states of the enzyme-bound complexes.

Differential Stabilities and Sequence-Dependent Base Pair Opening Dynamics of Watson–Crick Base Pairs with 5-Hydroxymethylcytosine, 5-Formylcytosine, or 5-Carboxylcytosine

Science.gov (United States)

2016-01-01

5-Hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) form during active demethylation of 5-methylcytosine (5mC) and are implicated in epigenetic regulation of the genome. They are differentially processed by thymine DNA glycosylase (TDG), an enzyme involved in active demethylation of 5mC. Three modified Dickerson–Drew dodecamer (DDD) sequences, amenable to crystallographic and spectroscopic analyses and containing the 5′-CG-3′ sequence associated with genomic cytosine methylation, containing 5hmC, 5fC, or 5caC placed site-specifically into the 5′-T8X9G10-3′ sequence of the DDD, were compared. The presence of 5caC at the X9 base increased the stability of the DDD, whereas 5hmC or 5fC did not. Both 5hmC and 5fC increased imino proton exchange rates and calculated rate constants for base pair opening at the neighboring base pair A5:T8, whereas 5caC did not. At the oxidized base pair G4:X9, 5fC exhibited an increase in the imino proton exchange rate and the calculated kop. In all cases, minimal effects to imino proton exchange rates occurred at the neighboring base pair C3:G10. No evidence was observed for imino tautomerization, accompanied by wobble base pairing, for 5hmC, 5fC, or 5caC when positioned at base pair G4:X9; each favored Watson–Crick base pairing. However, both 5fC and 5caC exhibited intranucleobase hydrogen bonding between their formyl or carboxyl oxygens, respectively, and the adjacent cytosine N4 exocyclic amines. The lesion-specific differences observed in the DDD may be implicated in recognition of 5hmC, 5fC, or 5caC in DNA by TDG. However, they do not correlate with differential excision of 5hmC, 5fC, or 5caC by TDG, which may be mediated by differences in transition states of the enzyme-bound complexes. PMID:25632825

Pair Production Constraints on Superluminal Neutrinos Revisited

International Nuclear Information System (INIS)

Brodsky, Stanley

2012-01-01

We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p 2 can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

Early pair housing increases solid feed intake and weight gains in dairy calves

OpenAIRE

Costa, J. H. C.; Meagher, R. K.; von Keyserlingk, M. A. G.; Weary, D. M.

2015-01-01

Dairy calves have traditionally been kept in individual pens throughout the milk-feeding period. Social rearing is associated with increased solid feed intake and hence higher weight gains before and after weaning. Little is known about the effect of the age at which social housing begins. The aim of this study was to assess the effects of early versus late pairing on feeding behavior and weight gain before and after weaning. Holstein bull calves were reared individually (n=8 calves), or pair...

PAIR PRODUCTION IN LOW-LUMINOSITY GALACTIC NUCLEI

International Nuclear Information System (INIS)

Moscibrodzka, M.; Gammie, C. F.; Dolence, J. C.; Shiokawa, H.

2011-01-01

Electron-positron pairs may be produced near accreting black holes by a variety of physical processes, and the resulting pair plasma may be accelerated and collimated into a relativistic jet. Here, we use a self-consistent dynamical and radiative model to investigate pair production by γγ collisions in weakly radiative accretion flows around a black hole of mass M and accretion rate M-dot . Our flow model is drawn from general relativistic magnetohydrodynamic simulations, and our radiation field is computed by a Monte Carlo transport scheme assuming the electron distribution function is thermal. We argue that the pair production rate scales as r -6 M -1 M-dot 6 . We confirm this numerically and calibrate the scaling relation. This relation is self-consistent in a wedge in M, M-dot parameter space. If M-dot is too low the implied pair density over the poles of the black hole is below the Goldreich-Julian density and γγ pair production is relatively unimportant; if M-dot is too high the models are radiatively efficient. We also argue that for a power-law spectrum the pair production rate should scale with the observables L X ≡ X-ray luminosity and M as L 2 X M -4 . We confirm this numerically and argue that this relation likely holds even for radiatively efficient flows. The pair production rates are sensitive to black hole spin and to the ion-electron temperature ratio which are fixed in this exploratory calculation. We finish with a brief discussion of the implications for Sgr A* and M87.

ENEA infrastructures toward the LFR development

International Nuclear Information System (INIS)

Tarantino, M.; Agostini, P.; Del Nevo, A.; Di Piazza, I.; Rozzia, D.

2013-01-01

ENEA has one of the most relevant EU R&D infrastructures for HLM technological development, and it is strongly involved in the main research programs worldwide supporting the development of sub-critical (MYRRHA) and critical lead cooled reactors (ALFRED). In these frames a large experimental program ranging from HLM thermal-hydraulic to large scale experiment has been implemented

Sensitivity analysis of physiochemical interaction model: which pair ...

African Journals Online (AJOL)

... of two model parameters at a time on the solution trajectory of physiochemical interaction over a time interval. Our aim is to use this powerful mathematical technique to select the important pair of parameters of this physical process which is cost-effective. Keywords: Passivation Rate, Sensitivity Analysis, ODE23, ODE45 ...

Electroproduction of pairs at beam-beam collision

International Nuclear Information System (INIS)

Bajer, V.N.; Katkov, V.M.; Strakhovenko, V.M.

1989-01-01

Charged particle pair production at beam-beam collision in electron-positron linear colliders has been discussed taking into account a finite size of the beams (both longitudinal and transverse) and end effects. Contributions of the main acting mechanisms are singled out which depend on the energy of initial particles and the masses of created particles. A spectral distribution of produced particles is presented. 15 refs

Soliton pair creation at finite temperatures

International Nuclear Information System (INIS)

Grigoriev, D.Yu.; Rubakov, V.A.

1988-01-01

Creation of soliton-antisoliton pairs at finite temperature is considered within a (1+1)-dimensional model of a real scalar field. It is argued that at certain temperatures, the soliton pair creation in quantum theory can be investigated by studying classical field evolution in real time. The classical field equations are solved numerically, and the pair creation rate and average number of solitons are evaluated. No peculiar suppression of the rate is observed. Some results on the sphaleron transitions in (1+1)-dimensional abelian Higgs model are also presented. (orig.)

Efficient Implementation of the Pairing on Mobilephones Using BREW

Science.gov (United States)

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.

A close-pair binary in a distant triple supermassive black hole system.

Science.gov (United States)

Deane, R P; Paragi, Z; Jarvis, M J; Coriat, M; Bernardi, G; Fender, R P; Frey, S; Heywood, I; Klöckner, H-R; Grainge, K; Rumsey, C

2014-07-03

Galaxies are believed to evolve through merging, which should lead to some hosting multiple supermassive black holes. There are four known triple black hole systems, with the closest black hole pair being 2.4 kiloparsecs apart (the third component in this system is at 3 kiloparsecs), which is far from the gravitational sphere of influence (about 100 parsecs for a black hole with mass one billion times that of the Sun). Previous searches for compact black hole systems concluded that they were rare, with the tightest binary system having a separation of 7 parsecs (ref. 10). Here we report observations of a triple black hole system at redshift z = 0.39, with the closest pair separated by about 140 parsecs and significantly more distant from Earth than any other known binary of comparable orbital separation. The effect of the tight pair is to introduce a rotationally symmetric helical modulation on the structure of the large-scale radio jets, which provides a useful way to search for other tight pairs without needing extremely high resolution observations. As we found this tight pair after searching only six galaxies, we conclude that tight pairs are more common than hitherto believed, which is an important observational constraint for low-frequency gravitational wave experiments.

Nucleon-pair approximation to the nuclear shell model

Energy Technology Data Exchange (ETDEWEB)

Zhao, Y.M., E-mail: ymzhao@sjtu.edu.cn [Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Arima, A. [Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Musashi Gakuen, 1-26-1 Toyotamakami Nerima-ku, Tokyo 176-8533 (Japan)

2014-12-01

Atomic nuclei are complex systems of nucleons–protons and neutrons. Nucleons interact with each other via an attractive and short-range force. This feature of the interaction leads to a pattern of dominantly monopole and quadrupole correlations between like particles (i.e., proton–proton and neutron–neutron correlations) in low-lying states of atomic nuclei. As a consequence, among dozens or even hundreds of possible types of nucleon pairs, very few nucleon pairs such as proton and neutron pairs with spin zero, two (in some cases spin four), and occasionally isoscalar spin-aligned proton–neutron pairs, play important roles in low-energy nuclear structure. The nucleon-pair approximation therefore provides us with an efficient truncation scheme of the full shell model configurations which are otherwise too large to handle for medium and heavy nuclei in foreseeable future. Furthermore, the nucleon-pair approximation leads to simple pictures in physics, as the dimension of nucleon-pair subspace is always small. The present paper aims at a sound review of its history, formulation, validity, applications, as well as its link to previous approaches, with the focus on the new developments in the last two decades. The applicability of the nucleon-pair approximation and numerical calculations of low-lying states for realistic atomic nuclei are demonstrated with examples. Applications of pair approximations to other problems are also discussed.

Drift wave in pair-ion plasma

Indian Academy of Sciences (India)

ion plasma are discussed. It is shown that the temperature and/or mass difference of both species could produce drift wave in a pair-ion plasma. The results are discussed in the context of the fullerene pair-ion plasma experiment.

Development of double-pair double difference location algorithm and its application to the regular earthquakes and non-volcanic tremors

Science.gov (United States)

Guo, H.; Zhang, H.

2016-12-01

Relocating high-precision earthquakes is a central task for monitoring earthquakes and studying the structure of earth's interior. The most popular location method is the event-pair double-difference (DD) relative location method, which uses the catalog and/or more accurate waveform cross-correlation (WCC) differential times from event pairs with small inter-event separations to the common stations to reduce the effect of the velocity uncertainties outside the source region. Similarly, Zhang et al. [2010] developed a station-pair DD location method which uses the differential times from common events to pairs of stations to reduce the effect of the velocity uncertainties near the source region, to relocate the non-volcanic tremors (NVT) beneath the San Andreas Fault (SAF). To utilize advantages of both DD location methods, we have proposed and developed a new double-pair DD location method to use the differential times from pairs of events to pairs of stations. The new method can remove the event origin time and station correction terms from the inversion system and cancel out the effects of the velocity uncertainties near and outside the source region simultaneously. We tested and applied the new method on the northern California regular earthquakes to validate its performance. In comparison, among three DD location methods, the new double-pair DD method can determine more accurate relative locations and the station-pair DD method can better improve the absolute locations. Thus, we further proposed a new location strategy combining station-pair and double-pair differential times to determine accurate absolute and relative locations at the same time. For NVTs, it is difficult to pick the first arrivals and derive the WCC event-pair differential times, thus the general practice is to measure station-pair envelope WCC differential times. However, station-pair tremor locations are scattered due to the low-precision relative locations. The ability that double-pair data

Lewis pair polymerization by classical and frustrated Lewis pairs: Acid, base and monomer scope and polymerization mechanism

KAUST Repository

Zhang, Yuetao

2012-01-01

Classical and frustrated Lewis pairs (LPs) of the strong Lewis acid (LA) Al(C 6F 5) 3 with several Lewis base (LB) classes have been found to exhibit exceptional activity in the Lewis pair polymerization (LPP) of conjugated polar alkenes such as methyl methacrylate (MMA) as well as renewable α-methylene-γ-butyrolactone (MBL) and γ-methyl- α-methylene-γ-butyrolactone (γ-MMBL), leading to high molecular weight polymers, often with narrow molecular weight distributions. This study has investigated a large number of LPs, consisting of 11 LAs as well as 10 achiral and 4 chiral LBs, for LPP of 12 monomers of several different types. Although some more common LAs can also be utilized for LPP, Al(C 6F 5) 3-based LPs are far more active and effective than other LA-based LPs. On the other hand, several classes of LBs, when paired with Al(C 6F 5) 3, can render highly active and effective LPP of MMA and γ-MMBL; such LBs include phosphines (e.g., P tBu 3), chiral chelating diphosphines, N-heterocyclic carbenes (NHCs), and phosphazene superbases (e.g., P 4- tBu). The P 4- tBu/Al(C 6F 5) 3 pair exhibits the highest activity of the LP series, with a remarkably high turn-over frequency of 9.6 × 10 4 h -1 (0.125 mol% catalyst, 100% MMA conversion in 30 s, M n = 2.12 × 10 5 g mol -1, PDI = 1.34). The polymers produced by LPs at RT are typically atactic (P γMMBL with ∼47% mr) or syndio-rich (PMMA with ∼70-75% rr), but highly syndiotactic PMMA with rr ∼91% can be produced by chiral or achiral LPs at -78 °C. Mechanistic studies have identified and structurally characterized zwitterionic phosphonium and imidazolium enolaluminates as the active species of the current LPP system, which are formed by the reaction of the monomer·Al(C 6F 5) 3 adduct with P tBu 3 and NHC bases, respectively. Kinetic studies have revealed that the MMA polymerization by the tBu 3P/ Al(C 6F 5) 3 pair is zero-order in monomer concentration after an initial induction period, and the polymerization

Kinetic equations with pairing correlations

International Nuclear Information System (INIS)

Fauser, R.

1995-12-01

The Gorkov equations are derived for a general non-equilibrium system. The Gorkov factorization is generalized by the cumulant expansion of the 2-particle correlation and by a generalized Wick theorem in the case of a perturbation expansion. A stationary solution for the Green functions in the Schwinger-Keldysh formalism is presented taking into account pairing correlations. Especially the effects of collisional broadening on the spectral functions and Green functions is discussed. Kinetic equations are derived in the quasi-particle approximation and in the case of particles with width. Explicit expressions for the self-energies are given. (orig.)

Drell-Yan lepton pair photoproduction

International Nuclear Information System (INIS)

Badalyan, R.G.; Grabskij, V.O.; Matinyan, S.G.

1989-01-01

The study of photon structure functions by spectra of massive lepton pairs (M l + l - ≥ 2 GeV) in photon fragmentation region in γp-interactions at high energies is suggested. In calculations of Drell-Yan lepton pair inclusive spectra in γp-interactions for photon structure functions there are used results obtained within QCD, data on γγ-interactions in e + e - → e + e - X on colliders as well as results from the analysis of vector meson non-diffractive photoproduction at high energies. It is shown that there exists a sufficienly wide kinematic region over variables X l + l - and M l + l - , wherein photon structure functions can be studied by spectra of Grell-Yan lepton pairs in the processes of their photoproduction. 31 refs.; 6 figs.; 1 tab

The Effects of Musical Fit on Choice Between Competing Pairs of Cultural Products

Directory of Open Access Journals (Sweden)

Joanne P. S. Yeoh

2010-01-01

Full Text Available Previous studies have claimed that music can prime the selection of certain products and influence consumers’ propensity to spend because it activates related knowledge of the world and subsequently raises the salience of certain products and behaviors associated with that music. Music that corresponds with the attributes of certain products therefore can prime the selection of those products. Ethnically Chinese Malaysian participants were presented with six pairs of products, each containing a Malay or an Indian version of the product in question, and asked to state a preference for one from that pair. Malay or Indian music was played simultaneously in the background. Product choices corresponded with the ethnicity of the background music played. This demonstrates that music ‘fit’ can influence product choice when consumers do not have a clear existing preference for one product over another.

Development, Validation and Summative Evaluation of Card Pairing Games for Selected Math 8 Topics

Directory of Open Access Journals (Sweden)

Ronald O. Ocampo

2015-12-01

Full Text Available Traditional classroom situation where students are taught predominantly of lecture-discussion method put the classroom in a mathophobic atmosphere. Oftentimes, students exposed to this classroom atmosphere lead to math anxiety and eventually hate the subject and the teacher. Addressing this, varied interactive strategies to create an atmosphere of discourse has been developed and promoted. The use of instructional games has been viewed as one strategy that promotes active learning inside the classroom. Instructional games support constructivist learning and social learning. This study is aimed at developing, validating and evaluating card pairing games for specific topics in Math 8. The Research and Development model ( R& D was used. The card pairing games was validated by subject experts and experts in developing games. In evaluating the card pairing games, the Quasi-Experimental Pretest-Posttest design was used. There are six card pairing games developed for specific topics in Math 8; the card pairing game is highly valid based on the result of the validation; Students exposed to card pairing game become more intact (homogeneous; Students exposed to card games enhance academic performance. It is recommended to test the effectiveness of card pairing games to other group of students; Encourage math teachers to use the developed math card pairing games for classroom instruction; Develop other card pairing game for specific topics in math.

Variational study of the pair hopping model

International Nuclear Information System (INIS)

Fazekas, P.

1990-01-01

We study the ground state of a Hamiltonian introduced by Kolb and Penson for modelling situations in which small electron pairs are formed. The Hamiltonian consists of a tight binding band term, and a term describing the nearest neighbour hopping of electron pairs. We give a Gutzwiller-type variational treatment, first with a single-parameter Ansatz treated in the single site Gutzwiller approximation, and then with more complicated trial wave functions, and an improved Gutzwiller approximation. The calculation yields a transition from a partially paired normal state, in which the spin susceptibility has a diminished value, into a fully paired state. (author). 16 refs, 2 figs

Feasibility of ion-pair/supercritical fluid extraction of an ionic compound--pseudoephedrine hydrochloride.

Science.gov (United States)

Eckard, P R; Taylor, L T

1997-02-01

The supercritical fluid extraction (SFE) of an ionic compound, pseudoephedrine hydrochloride, from a spiked-sand surface was successfully demonstrated. The effect of carbon dioxide density (CO2), supercritical fluid composition (pure vs. methanol modified), and the addition of a commonly used reversed-phase liquid chromatographic ion-pairing reagent, 1-heptanesulfonic acid, sodium salt, on extraction efficiency was examined. The extraction recoveries of pseudoephedrine hydrochloride with the addition of the ion-pairing reagent from a spiked-sand surface were shown to be statistically greater than the extraction recoveries without the ion-pairing reagent with both pure and methanol-modified carbon dioxide.

Top Quark Pair Production in Association with a Jet with Next-to-Leading-Order QCD Off-Shell Effects at the Large Hadron Collider.

Science.gov (United States)

Bevilacqua, G; Hartanto, H B; Kraus, M; Worek, M

2016-02-05

We present a complete description of top quark pair production in association with a jet in the dilepton channel. Our calculation is accurate to next-to-leading order (NLO) in QCD and includes all nonresonant diagrams, interferences, and off-shell effects of the top quark. Moreover, nonresonant and off-shell effects due to the finite W gauge boson width are taken into account. This calculation constitutes the first fully realistic NLO computation for top quark pair production with a final state jet in hadronic collisions. Numerical results for differential distributions as well as total cross sections are presented for the Large Hadron Collider at 8 TeV. With our inclusive cuts, NLO predictions reduce the unphysical scale dependence by more than a factor of 3 and lower the total rate by about 13% compared to leading-order QCD predictions. In addition, the size of the top quark off-shell effects is estimated to be below 2%.

Enhanced stability of bound pairs at nonzero lattice momenta

International Nuclear Information System (INIS)

Kornilovitch, Pavel

2004-01-01

A two-body problem on the square lattice is analyzed. The interaction potential consists of strong on-site repulsion and nearest-neighbor attraction. The exact pairing conditions are derived for s-, p-, and d-symmetric bound states. The pairing conditions are strong functions of the total pair momentum K. It is found that the stability of pairs increases with K. At weak attraction, the pairs do not form at the Γ point but stabilize at lattice momenta close to the Brillouin zone boundary. The phase boundaries in the momentum space, which separate stable and unstable pairs, are calculated. It is found that the pairs are formed easier along the (π,0) direction than along the (π,π) direction. This might lead to the appearance of 'hot pairing spots' on the K x and K y axes

Spin polarization in top pair production in association with two photons at NLO+PS

CERN Document Server

Luisoni, Gionata

2018-01-01

This talk focuses on the impact of top-quark spin polarization effects in Higgs boson production in association with a top-quark pair, where the Higgs boson decays to two photons. Predictions for the signal are compared with direct top-quark pair production in association with two photons at NLO+PS.

Spin polarization in top pair production in association with two photons at NLO+PS

CERN Document Server

Luisoni, Gionata

2017-01-01

This talk focuses on the impact of top-quark spin polarization effects in Higgs boson production in association with a top-quark pair, where the Higgs boson decays to two photons. Predictions for the signal are compared with direct top-quark pair production in association with two photons at NLO+PS.

Butterflyfishes as a System for Investigating Pair Bonding

KAUST Repository

Nowicki, Jessica

2017-11-14

For many animals, affiliative relationships such as pair bonds form the foundation of society, and are highly adaptive. Animal systems amenable for comparatively studying pair bonding are important for identifying underlying biological mechanisms, but mostly exist in mammals. Better establishing fish systems will enable comparison of pair bonding mechanisms across taxonomically distant lineages that may reveal general underlying principles. We examined the utility of wild butterflyfishes (f: Chaetodontidae; g: Chaetodon) for comparatively studying pair bonding. Stochastic character mapping inferred that within the family, pairing is ancestral, with at least seven independent transitions to group formation and seven transition to solitary behavior from the late Miocene to recent. In six sympatric and wide-spread species representing a clade with one ancestrally reconstructed transition from paired to solitary grouping, we then verified social systems at Lizard Island, Australia. In situ observations confirmed that Chaetodon baronessa, C. lunulatus, and C. vagabundus are predominantly pair bonding, whereas C. rainfordi, C. plebeius, and C. trifascialis are predominantly solitary. Even in the predominantly pair bonding species, C. lunulatus, a proportion of adults (15 %) are solitary. Importantly, inter- and intra-specific differences in social systems do not co-vary with other previously established attributes (geographic occurrence, parental care, diet, or territoriality). Hence, the proposed butterflyfish populations are promising for comparative analyses of pair bonding and its mechanistic underpinnings. Avenues for further developing the system are proposed, including determining whether the utility of these species applies across their geographic disruptions.

Pair potentials and structure factors of liquid alkali metals

International Nuclear Information System (INIS)

Kumaravadivel, R.; Tosi, M.P.

1984-03-01

Measured structure factors of liquid alkali metals are examined in the framework of screened-pair-potentials theory. Information on the main attractive well in the effective pair potential is obtained from the structural data by an approximate method stemming from an optimized random phase treatment of the indirect ion-ion attraction. The results are compared with a variety of theoretical pair potentials in the cases of sodium and potassium, after a test of the method against computer simulation data on a model for rubidium. Results for the other alkali metals are also given and discussed. The small-angle scattering region is then examined in considerable detail, with special attention to the possibility of a linear term in a series expansion of the structure factor at very small momentum transfer. Although sensitivity to both the bare electron-ion coupling and the local field factor in the screening function is demonstrated and analyzed, no linear term of the magnitude reported in recent X-ray diffraction experiments is found in the present theoretical framework. (author)

Nonrandom network connectivity comes in pairs

Directory of Open Access Journals (Sweden)

Felix Z. Hoffmann

2017-02-01

Full Text Available Overrepresentation of bidirectional connections in local cortical networks has been repeatedly reported and is a focus of the ongoing discussion of nonrandom connectivity. Here we show in a brief mathematical analysis that in a network in which connection probabilities are symmetric in pairs, Pij = Pji, the occurrences of bidirectional connections and nonrandom structures are inherently linked; an overabundance of reciprocally connected pairs emerges necessarily when some pairs of neurons are more likely to be connected than others. Our numerical results imply that such overrepresentation can also be sustained when connection probabilities are only approximately symmetric.

How do colonial Eurasian Griffon Vultures prevent extra-pair mating?

Directory of Open Access Journals (Sweden)

Joan Bertran

2016-02-01

Full Text Available In colonial breeding species, preventive measures to reduce the risks of extra-pair copulations (EPCs should reflect the actual risk perceived by males (e.g., proximity of neighbors, intrusions into the nest mainly during the fertile period. In colonial vultures, specific studies examining the preventive measures that minimize the risks of EPCs occurring within the competitive context of colonial breeding have not been conducted. Here we tested at Eurasian Griffon Vulture (Gyps fulvus nesting sites the intensity of paternity assurance behavior, shown as frequency and duration of within-pair copulations (WPCs, potential mate vigilance or nest attendance, and levels of aggressivity. This was measured according to the frequency of territorial intrusions and comparison of the fertile vs. the non-fertile period. Our findings suggest that the frequency of WPCs and their duration increased significantly during the presumed fertile period, regarded as the period when Griffon pairs spent significantly more time together at their nests. In addition, low levels of territorial intrusions were observed, an aggressive response of pairs towards intruders, and a relatively high presence of pairs at the nests during the fertile period. Thus, although nesting sites are subject to low exposure to EPC attempts, the increased frequency and duration of copulations during the fertile period suggests that, under pressure from the colonial breeding system, a higher rate of copulations is the most effective preventive mechanism against relative uncertainty of paternity.

Think Pair Share with Formative Assessment for Junior High School Student

Science.gov (United States)

Pradana, O. R. Y.; Sujadi, I.; Pramudya, I.

2017-09-01

Geometry is a science related to abstract thinking ability so that not many students are able to understand this material well. In this case, the learning model plays a crucial role in improving student achievement. This means that a less precise learning model will cause difficulties for students. Therefore, this study provides a quantitative explanation of the Think Pair Share learning model combined with the formative assessment. This study aims to test the Think Pair Share with the formative assessment on junior high school students. This research uses a quantitative approach of Pretest-Posttest in control group and experiment group. ANOVA test and Scheffe test used to analyse the effectiveness this learning. Findings in this study are student achievement on the material geometry with Think Pair Share using formative assessment has increased significantly. This happens probably because this learning makes students become more active during learning. Hope in the future, Think Pair Share with formative assessment be a useful learning for teachers and this learning applied by the teacher around the world especially on the material geometry.

W+- pairs and neutral currents at ISABELLE

International Nuclear Information System (INIS)

Mikaelian, K.O.

1975-01-01

A report is presented on two different types of processes which may form part of the weak interactions program. The first is the production of pairs of charged weak bosons in the process pp → W + W - X; the second involves searching for neutral current effects in the rate for ordinary lepton production, without measuring any charge asymmetry or helicities using the reaction pp → l + l - X

A study of electron-positron pair equilibria in models of compact X- and gamma-ray sources

International Nuclear Information System (INIS)

Bjoernsson, G.

1990-01-01

Thermal electron-positron pair equilibria in two temperature models of compact x ray and gamma ray sources are studied. The pairs are assumed to be heated by Coulomb interaction with the much hotter protons and cooled by bremsstrahlung emission, Compton scattering, and annihilation. Two parameters, the proton optical depth and the compactness, characterize each equilibrium state. It is shown that a careful account of the energy balance is very important when the stability properties of the pair equilibria in a spherical plasma cloud are determined. The equilibria are found to be unstable in a very limited range of compactness and proton optical depth. This particular instability is unlikely to be the cause of the observed variability of the compact sources and implies that it is possible to build up high pair densities by a thermal mechanism in two temperature environments. The most important result considers the effects of pairs on the structure of geometrically and effectively optically thin accretion disks. A new approach for solving for the equilibrium structure of the disks is presented. In effect, the pair equilibrium states are projected into the space spanned by the disk structure parameters. This allows a direct visualization of all possible disk solutions at once. Each solution profile needs to be calculated only once and a complete disk solution is obtained by a simple radial coordinate transformation. The disk solutions are thus seen to be scale free in terms of the radial coordinate as well as in terms of the mass of the central object and the accretion rate. Two particular disk solutions are given. It is shown that including electron-positron pairs in the disk structure calculations leads to a breakdown of the thin disk assumptions and that more detailed disk modeling is required before electron-positron pairs can be self-consistently included

Becoming independent through au pair migration

DEFF Research Database (Denmark)

Dalgas, Karina Märcher

2015-01-01

. This article argues that, despite this critique, au pairing does play an important formative role for young Filipinas because it opens up for experiences abroad that enable them to be recognised as independent adults in Philippine society. Rather than autonomy, however, au pairs define their independence...

Pairing mechanism in oxide superconductors

International Nuclear Information System (INIS)

Hirsch, J.E.

1988-01-01

A useful way to learn about the pairing mechanism that is responsible for high T c superconductivity is to study properties of model Hamiltonians on small systems. The goal is to find the simplest model that can describe the essential physics of high T c superconductivity. The authors have used Monte Carlo simulation and exact diagonalization techniques to study properties of systems of up to 64 sites. Their results show that spin fluctuations and other spin related mechanisms induced by a Hubbard on-site repulsion U are not likely to give rise to pairing, neither in one nor in multiple band models. In contrast, charge fluctuations in a model with both strong U and V (repulsion between Cu and O) are shown to give rise to pairing and it is suggested that this model provides a plausible mechanism for high T c superconductivity

Investigation of coulomb and pairing effects using new developed empirical formulas for proton-induced reaction cross sections

International Nuclear Information System (INIS)

Tel, E.; Aydin, E. G.; Aydin, A.; Kaplan, A.; Boeluekdemir, M. H.; Okuducu, S.

2010-01-01

We have investigated Coulomb and pairing effects by using new empirical formulas including the new coefficients for (p, α) at 17.9 MeV, (p, np) at 22.3 MeV, and (p, nα) at 24.8 and 28.5 MeV energies. A new formula is obtained by adjusting Levkovskii's original asymmetry parameter formula and also Tel et al. formula for proton-induced reactions. The new coefficients by using least-squares fitting method for the reactions are determined. In addition, the findings of the present study are compared with the available experimental data.

Frequent Pairs in Data Streams: Exploiting Parallelism and Skew

DEFF Research Database (Denmark)

Campagna, Andrea; Kutzkow, Konstantin; Pagh, Rasmus

2011-01-01

We introduce the Pair Streaming Engine (PairSE) that detects frequent pairs in a data stream of transactions. Our algorithm finds the most frequent pairs with high probability, and gives tight bounds on their frequency. It is particularly space efficient for skewed distribution of pair supports...... items mining in data streams. We show how to efficiently scale these approaches to handle large transactions. We report experimental results showcasing precision and recall of our method. In particular, we find that often our method achieves excellent precision, returning identical upper and lower...... bounds on the supports of the most frequent pairs....

Dependence of the lone pair of bismuth on coordination environment and pressure

DEFF Research Database (Denmark)

Olsen, Lars Arnskov; López-Solano, Javier; García, Alberto

2010-01-01

DFT calculations have been carried out for Cu4Bi5S10 and Bi2S3 to provide an analysis of the relation between electronic structure, lone electron pairs and the local geometry. The effect of pressure is considered in Bi2S3 and the results are compared to published experimental data. Bi3+ in Cu4Bi5S......-shared charge. These lobes are related to an effective Bi s–Bi p hybridization resulting from coupling to S p orbitals, supporting the modern view of the origin of the stereochemically active lone pair. No effective Bi s–p hybridization is seen for the symmetric site in Cu4Bi5S10, whereas Bi s–p hybridization...

Frustrated Lewis Pairs

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 11. Frustrated Lewis Pairs : Enabling via inability. Sanjoy Mukherjee ... Author Affiliations. Sanjoy Mukherjee Pakkirisamy Thilagar1. Department of Inorgainic and Physical Chemistry Indian Institute of Science Bangalore 560 012, India.

School effects on non-verbal intelligence and nutritional status in rural Zambia.

Science.gov (United States)

Hein, Sascha; Tan, Mei; Reich, Jodi; Thuma, Philip E; Grigorenko, Elena L

2016-02-01

This study uses hierarchical linear modeling (HLM) to examine the school factors (i.e., related to school organization and teacher and student body) associated with non-verbal intelligence (NI) and nutritional status (i.e., body mass index; BMI) of 4204 3 rd to 7 th graders in rural areas of Southern Province, Zambia. Results showed that 23.5% and 7.7% of the NI and BMI variance, respectively, were conditioned by differences between schools. The set of 14 school factors accounted for 58.8% and 75.9% of the between-school differences in NI and BMI, respectively. Grade-specific HLM yielded higher between-school variation of NI (41%) and BMI (14.6%) for students in grade 3 compared to grades 4 to 7. School factors showed a differential pattern of associations with NI and BMI across grades. The distance to a health post and teacher's teaching experience were the strongest predictors of NI (particularly in grades 4, 6 and 7); the presence of a preschool was linked to lower BMI in grades 4 to 6. Implications for improving access and quality of education in rural Zambia are discussed.

Evaluative Conditioning Can Be Modulated by Memory of the CS-US Pairings at the Time of Testing

Science.gov (United States)

Gast, Anne; De Houwer, Jan; De Schryver, Maarten

2012-01-01

Evaluative conditioning (EC) is the valence change of a (typically neutral) stimulus (CS) that is due to the previous pairing with another (typically valent) stimulus (US). It has been repeatedly shown that EC effects are stronger or existent only if participants know which US was paired with which CS. Knowledge of the CS-US pairings is usually…

On pair-absorption in intrinsic vapours

International Nuclear Information System (INIS)

Hotop, R.; Niemax, K.; Schlueter, D.

1982-01-01

The bound-state pair-absorption bands Cs(6 2 S 1 sub(/) 2 ) + Cs(6 2 S 1 sub(/) 2 ) + hν → Cs(5 2 D 5 sub(/) 2 sub(,) 3 sub(/) 2 ) + Cs(6 2 P 1 sub(/) 2 ) and the K-K continuum-state pair-absorptions in the wavelength region 2.350 <= lambda <= 2.850 Angstroem have been investigated experimentally. In the case of the bound-state pair-absorption bands a theoretical approach for the absorption cross section at the band centre is given which is in good agreement with the experimental observation. Differences between our and the theoretical formulas given by the Stanford group are discussed. (orig.)

Particle-number fluctuations and neutron-proton pairing effects on proton and neutron radii of even-even N Almost-Equal-To Z nuclei

Energy Technology Data Exchange (ETDEWEB)

Douici, M.; Allal, N. H.; Fellah, M.; Benhamouda, N.; Oudih, M. R. [Laboratoire de Physique Theorique, Faculte de Physique, USTHB BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria) and Institut des Sciences et Technologie, Centre Universitaire de Khemis Miliana, Route de Theniet-El-Had, 44225 Khemis-Milia (Algeria); Laboratoire de Physique Theorique, Faculte de Physique, USTHB BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria) and Centre de Recherche Nucleaire d' Alger, COMENA, BP399 Alger-Gare, Alger (Algeria); Laboratoire de Physique Theorique, Faculte de Physique, USTHB BP 32 El-Alia, 16111 Bab-Ezzouar, Alger (Algeria)

2012-10-20

The particle-number fluctuation effect on the root-mean-square (rms) proton and neutron radii of even-even N Almost-Equal-To Z nuclei is studied in the isovector neutron-proton (np) pairing case using an exact particle-number projection method and the Woods-Saxon model.

Decomposing variation in male reproductive success: age-specific variances and covariances through extra-pair and within-pair reproduction.

Science.gov (United States)

Lebigre, Christophe; Arcese, Peter; Reid, Jane M

2013-07-01

Age-specific variances and covariances in reproductive success shape the total variance in lifetime reproductive success (LRS), age-specific opportunities for selection, and population demographic variance and effective size. Age-specific (co)variances in reproductive success achieved through different reproductive routes must therefore be quantified to predict population, phenotypic and evolutionary dynamics in age-structured populations. While numerous studies have quantified age-specific variation in mean reproductive success, age-specific variances and covariances in reproductive success, and the contributions of different reproductive routes to these (co)variances, have not been comprehensively quantified in natural populations. We applied 'additive' and 'independent' methods of variance decomposition to complete data describing apparent (social) and realised (genetic) age-specific reproductive success across 11 cohorts of socially monogamous but genetically polygynandrous song sparrows (Melospiza melodia). We thereby quantified age-specific (co)variances in male within-pair and extra-pair reproductive success (WPRS and EPRS) and the contributions of these (co)variances to the total variances in age-specific reproductive success and LRS. 'Additive' decomposition showed that within-age and among-age (co)variances in WPRS across males aged 2-4 years contributed most to the total variance in LRS. Age-specific (co)variances in EPRS contributed relatively little. However, extra-pair reproduction altered age-specific variances in reproductive success relative to the social mating system, and hence altered the relative contributions of age-specific reproductive success to the total variance in LRS. 'Independent' decomposition showed that the (co)variances in age-specific WPRS, EPRS and total reproductive success, and the resulting opportunities for selection, varied substantially across males that survived to each age. Furthermore, extra-pair reproduction increased

Effects of temperature and isotopic substitution on electron attachment dynamics of guanine–cytosine base pair: Ring-polymer and classical molecular dynamics simulations

International Nuclear Information System (INIS)

Minoshima, Yusuke; Seki, Yusuke; Takayanagi, Toshiyuki; Shiga, Motoyuki

2016-01-01

Highlights: • Dynamics of excess electron attachment to guanine–cytosine base pair. • Ring-polymer and classical molecular dynamics simulations are performed. • Temperature and isotope substitution effects are investigated. - Abstract: The dynamical process of electron attachment to a guanine–cytosine pair in the normal (h-GC) and deuterated (d-GC) forms has been studied theoretically by semiclassical ring-polymer molecular dynamics (RPMD) simulations using the empirical valence bond model. The initially formed dipole-bound anion is converted rapidly to the valence-bound anion within about 0.1 ps in both h-GC and d-GC. However, the subsequent proton transfer in h-GC occurs with a rate five times greater than the deuteron transfer in d-GC. The change of rates with isotopic substitution and temperature variation in the RPMD simulations are quantitatively and qualitatively different from those in the classical molecular dynamics (MD) simulations, demonstrating the importance of nuclear quantum effects on the dynamics of this system.

Effects of temperature and isotopic substitution on electron attachment dynamics of guanine–cytosine base pair: Ring-polymer and classical molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Minoshima, Yusuke; Seki, Yusuke [Department of Chemistry, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama City, Saitama 338-8570 (Japan); Takayanagi, Toshiyuki, E-mail: tako@mail.saitama-u.ac.jp [Department of Chemistry, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama City, Saitama 338-8570 (Japan); Shiga, Motoyuki [Center for Computational Science and E-Systems, Japan Atomic Energy Agency, 148-4, Kashiwanoha Campus, 178-4 Wakashiba, Kashiwa, Chiba 277-0871 (Japan)

2016-06-15

Highlights: • Dynamics of excess electron attachment to guanine–cytosine base pair. • Ring-polymer and classical molecular dynamics simulations are performed. • Temperature and isotope substitution effects are investigated. - Abstract: The dynamical process of electron attachment to a guanine–cytosine pair in the normal (h-GC) and deuterated (d-GC) forms has been studied theoretically by semiclassical ring-polymer molecular dynamics (RPMD) simulations using the empirical valence bond model. The initially formed dipole-bound anion is converted rapidly to the valence-bound anion within about 0.1 ps in both h-GC and d-GC. However, the subsequent proton transfer in h-GC occurs with a rate five times greater than the deuteron transfer in d-GC. The change of rates with isotopic substitution and temperature variation in the RPMD simulations are quantitatively and qualitatively different from those in the classical molecular dynamics (MD) simulations, demonstrating the importance of nuclear quantum effects on the dynamics of this system.

Galactic Pairs in the Early Universe

Science.gov (United States)

Kohler, Susanna

2018-02-01

In the spirit of Valentines Day, today well be exploring apparent pairs of galaxies in the distant, early universe. How can we tell whether these duos are actually paired galaxies, as opposed to disguised singles?Real Pair, or Trick of the Light?In the schematic timeline of the universe, the epoch of reionization is when the first galaxies and quasars began to form and evolve. [NASA]The statistics of merging galaxies throughout the universe reveal not only direct information about how galaxies interact, but also cosmological information about the structure of the universe. While weve observed many merging galaxy pairs at low redshift, however, its much more challenging to identify these duos in the early universe.A merging pair of galaxies at high redshift appears to us as a pair of unresolved blobs that lie close to each other in the sky. But spotting such a set of objects doesnt necessarily mean were looking at a merger! There are three possible scenarios to explain an observed apparent duo:Its a pair of galaxies in a stage of merger.Its a projection coincidence; the two galaxies arent truly near each other.Its a single galaxy being gravitationally lensed by a foreground object. This strong lensing produces the appearance of multiple galaxies.Hubble photometry of one of the three galaxy groups identified at z 8, with the galaxies in the image labeled with their corresponding approximate photometric redshifts. [Adapted from Chaikin et al. 2018]Hunting for Distant DuosIn a recent study led by Evgenii Chaikin (Peter the Great St. Petersburg Polytechnic University, Russia), a team of scientists has explored the Hubble Ultra Deep Field in search ofhigh-redshift galaxies merging during the epoch of reionization, when the first galaxies formed and evolved.Using an approach called the dropout technique, which leverages the visibility of the galaxies in different wavelength filters, Chaikin and collaborators obtain approximate redshifts for an initial sample of 7

Pair housing and enhanced milk allowance increase play behavior and improve performance in dairy calves

DEFF Research Database (Denmark)

Jensen, Margit Bak; Duve, Linda Rosager; Weary, D. M.

2015-01-01

-housed calves could perform social play behavior (play fighting), and the duration of this was greater on d 15 and 29 than on d 43 [8.3, 10.7 and 3.5 (±1.3) corresponding to 69, 115 and 12 s/24 h for d 15, 29, and 43]. Among calves on enhanced milk, pair-housed animals had a greater concentrate intake than...... observed no effect of pair versus individual housing [810 and 840 (±40) g/d]. In conclusion, greater durations of play behavior in enhanced-fed calves suggest an animal welfare benefit of this feeding method. Enhanced-fed calves consumed less concentrate, but pair housing stimulated concentrate intake......To investigate the effects of social housing and milk feeding on play behavior and performance, 48 Holstein-Friesian male and female calves were either individually or pair housed in straw-bedded pens (3.0 m × 4.5 m). Half of the calves in each housing treatment were fed a standard milk allowance...

QUANTITATIVE ION-PAIR EXTRACTION OF 4(5)-METHYLIMIDAZOLE FROM CARAMEL COLOR AND ITS DETERMINATION BY REVERSED-PHASE ION-PAIR LIQUID-CHROMATOGRAPHY

DEFF Research Database (Denmark)

Thomsen, Mohens; Willumsen, Dorthe

1981-01-01

A procedure for quantitative ion-pair extraction of 4(5)-methylimidazole from caramel colour using bis(2-ethylhexyl)phosphoric acid as ion-pairing agent has been developed. Furthermore, a reversed-phase ion-pair liquid chromatographic separation method has been established to analyse the content...

Observation of correlated atom pairs in spontaneous four wave mixing of two colliding Bose-Einstein condensates; Observation de paires d'atomes correles au travers de la collision de deux condensats de Bose-Einstein

Energy Technology Data Exchange (ETDEWEB)

Perrin, A

2007-11-15

In this thesis, we report on the observation of pairs of correlated atoms produced in the collision of two Bose-Einstein condensates of metastable helium. Three laser beams perform a Raman transfer which extracts the condensate from the magnetic trap and separates it into two parts with opposite mean momenta. While the condensates propagate, elastic scattering of pairs of atoms occurs, whose momenta satisfy energy and momentum conservation laws. Metastable helium atoms large internal energy allows the use of a position-sensitive, single-atom detector which permits a three-dimensional reconstruction of the scattered atoms'momenta. The statistics of these momenta show correlations for atoms with opposite momenta. The measured correlation volume can be understood from the uncertainty-limited momentum spread of the colliding condensates. This interpretation is confirmed by the observation of the momentum correlation function for two atoms scattered in the same direction. This latter effect is a manifestation of the Hanbury Brown-Twiss effect for indistinguishable bosons. Such a correlated-atom-pair source is a first step towards experiments in which one would like to confirm the pairs'entanglement. (author)

Nanoscale strain-induced pair suppression as a vortex-pinning mechanism in high-temperature superconductors

International Nuclear Information System (INIS)

Llordes, Anna; Palau, A.; Gazquez, J.; Coll, M.; Vlad, R.; Pomar, A.; Arbiol, Jordi; Guzman, Roger; Ye, S.; Rouco, V.; Sandiumenge, Felip; Ricart, Susagna; Puig, Teresa; Varela del Arco, Maria; Chataigner, D.; Vanacken, J.; Gutierrez, J.; Moschalkov, V.; Deutscher, G.; Magen Dominguez, Cesar; Obradors, Xavier

2012-01-01

Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centers in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa 2 Cu 3 O 7 matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.

Pair Interactions and Mode of Communication: Comparing Face-to-Face and Computer Mediated Communication

Science.gov (United States)

Tan, Lan Liana; Wigglesworth, Gillian; Storch, Neomy

2010-01-01

In today's second language classrooms, students are often asked to work in pairs or small groups. Such collaboration can take place face-to-face, but now more often via computer mediated communication. This paper reports on a study which investigated the effect of the medium of communication on the nature of pair interaction. The study involved…

A stochastic model for identifying differential gene pair co-expression patterns in prostate cancer progression

Directory of Open Access Journals (Sweden)

Mao Yu

2009-07-01

Full Text Available Abstract Background The identification of gene differential co-expression patterns between cancer stages is a newly developing method to reveal the underlying molecular mechanisms of carcinogenesis. Most researches of this subject lack an algorithm useful for performing a statistical significance assessment involving cancer progression. Lacking this specific algorithm is apparently absent in identifying precise gene pairs correlating to cancer progression. Results In this investigation we studied gene pair co-expression change by using a stochastic process model for approximating the underlying dynamic procedure of the co-expression change during cancer progression. Also, we presented a novel analytical method named 'Stochastic process model for Identifying differentially co-expressed Gene pair' (SIG method. This method has been applied to two well known prostate cancer data sets: hormone sensitive versus hormone resistant, and healthy versus cancerous. From these data sets, 428,582 gene pairs and 303,992 gene pairs were identified respectively. Afterwards, we used two different current statistical methods to the same data sets, which were developed to identify gene pair differential co-expression and did not consider cancer progression in algorithm. We then compared these results from three different perspectives: progression analysis, gene pair identification effectiveness analysis, and pathway enrichment analysis. Statistical methods were used to quantify the quality and performance of these different perspectives. They included: Re-identification Scale (RS and Progression Score (PS in progression analysis, True Positive Rate (TPR in gene pair analysis, and Pathway Enrichment Score (PES in pathway analysis. Our results show small values of RS and large values of PS, TPR, and PES; thus, suggesting that gene pairs identified by the SIG method are highly correlated with cancer progression, and highly enriched in disease-specific pathways. From