Intrapair Distance Research Articles

Social behaviour in the non-breeding season in Great Tits Parus major and Willow Tits Poecile montanus: differences in juvenile birds’ route to territorial ownership, and pair-bond stability and mate protection in adults

Great Tits Parus major and Willow Tits Poecile montanus are small passerine monogamous species that live in dominance-structured flocks outside the breeding season. Within such flocks, males dominate females, and within sex, adults generally dominate juveniles (first-year birds). However, whereas Willow Tits maintain a yearlong defence of large territories and their flocks have a constant membership, the Great Tits maintain looser organizations of their flocks that vary in size, and the birds move around irrespective of territorial ranges. I compared the aggressive behaviour between juvenile conspecifics of Great and Willow Tits from July through April during 2004–2014, and the intra-pair behaviour of adults during November–February in 2011−2014 in a subalpine forest in Budal, central Norway. Two maxima of aggressive interactions were found among juveniles of both species: one in August–September and one in March–April. For Great Tits the autumn-interactions were probably due to competition for food, whereas the spring-interactions reflected competition for territorial space. For Willow Tits, the interactions in August – September were caused by competition for flock membership and ownership for a territory in March–April. Because flock membership in general is the only possible way to territory ownership, also the aggressive behaviour among juvenile Willow Tits in autumn is most likely linked to territorial behaviour. I found three circumstances of immediate benefits of the pair bond for adult Willow Tits that are consistent with the hypothesis of mate protection and that differed from that of Great Tit pairs: Willow Tits had a shorter intra-pair distance, females received less aggression, and they had a higher foraging rate when accompanied by their mate than did females of Great Tit pairs. One out of the five Great Tit pairs studied became divorced, whereas the bonds of three Willow Tit pairs were stable over at least three to four years.

Onset of plastic relaxation in the growth of Ge on Si(001) at low temperatures: Atomic-scale microscopy and dislocation modeling

We present a synergic experimental and theoretical investigation of the plastic relaxation onset in low-temperature Ge growth on Si(001). High-resolution transmission electron microscopy reveals that misfit is released by pairs of coupled 60\ifmmode^\circ\else\textdegree\fi{} dislocations. Atomic resolution proved to be key in distinguishing pairs from single 90\ifmmode^\circ\else\textdegree\fi{} dislocations because of the revealed small intrapair dislocation distance (even less than 1 nm). By exploiting dislocation theory and molecular dynamics simulations, we demonstrate that the observed pairing naturally occurs as a result of the mutual interactions between the two dislocations. In particular, analytical models show that the stress field arising in a thin film when a dislocation segment lies at the interface with the substrate determines the most favored nucleation site for a new (complementary) dislocation that leads, after migration, to the coupling with the first in a stable position. At the growth temperature, further motion or recombination due to atomic scale effects is excluded by classical molecular dynamics simulations. A clear picture of the early stages in the strain relaxation emerges, gliding out of the interface and/or short-range climbing (as typically produced by annealing or higher temperature steps but not taking place under the present growth conditions) being required to transform pairs into edge dislocations. The present results also offer answers to the long-asked puzzling question about the mechanism originating 90\ifmmode^\circ\else\textdegree\fi{} dislocation in high-mismatch Ge/Si systems.

A fresh look at dense hydrogen under pressure. III. Two competing effects and the resulting intra-molecular H-H separation in solid hydrogen under pressure

A preliminary discussion of the general problem of localization of wave functions, and the way it is approached in theoretical condensed matter physics (Wannier functions) and theoretical chemistry (localized or fragment orbitals) is followed by an application of the ideas of Paper II in this series to the structures of hydrogen as they evolve under increasing pressure. The idea that emerges is that of simultaneously operative physical (reduction of available space by an increasingly stiff wall of neighboring molecules) and chemical (depopulation of the σ(g) bonding molecular orbital of H(2), and population of the antibonding σ(u)∗ MO) factors. The two effects work in the same direction of reducing the intermolecular separation as the pressure increases, but compete, working in opposite directions, in their effect on the intramolecular (nearest neighbor, intra-pair) distance. We examine the population of σ(g) and σ(u)∗ MOs in our numerical laboratory, as well as the total electron transfer (small), and polarization (moderate, where allowed by symmetry) of the component H(2) molecules. From a molecular model of two interacting H(2) molecules we find a linear relationship between the electron transfer from σ(g) to σ(u)∗ of a hydrogen molecular fragment and the intramolecular H-H separation, and that, in turn, allows us to estimate the expected bond lengths in H(2) under pressure if the first effect (that of simple confinement) was absent. In essence, the intramolecular H-H separations under pressure are much shorter than they would be, were there no physical/confinement effect. We then use this knowledge to understand how the separate E and PV terms contribute to hydrogen phase changes with increasing pressure.

An MD simulation to form an NV-N center using N 2 implantation into diamond

We have examined the dissociation process of a low-energy molecular beam making use of an empirical molecular dynamic simulation. The main concern was to explain why two (nitrogen molecule N 2) beams with different energy (sub-keV and keV) give a similar intrapair distance R N-N in diamond. It was due to the peculiar dependence of the lateral range straggling on the incident energy across a few keV. When a sub-keV (N 2) beam was implanted into a diamond, the dissociation elapsed a long time until it was settled in several hundreds fs because of multiple collisions. The range distribution caused by multiple collisions is almost isotropic whereas it becomes anisotropic when used a (N 2) beam with the higher energy than that. From the viewpoint of computation, a few keV is a critical energy to choose an algorithm MD or MC with binary collision approximation. For the case of sub-keV N 2 beam, MD is indispensable. This proved the reason of the apparent contradiction. Much later than the collision stage, a definite change further occurred in the long-range-order of the crystal at around 2 ps in diamond. It seems a phonon-assisted phenomenon would start then and might affect on the further events to be occurred later than 20 ps.

Exploring the mental number line via the size congruity effect.

To address the ongoing debate about the origins of the size effect (faster comparison time for smaller than larger numbers, given a fixed intrapair distance), an indication of automatic number processing was searched for. Participants performed a quantity comparison task in which they had to decide which of two sketched cups contained more liquid, while ignoring the number superimposed on each cup. In the congruent condition, the larger number appeared on the cup containing more liquid, while in the incongruent condition the larger number appeared on the cup containing less liquid. The size effect was found in a numerical comparison task, while in the quantity comparison task the size congruity effect decreased as the magnitude of the irrelevant numbers increased. Together, these results suggest that the size effect reflects a basic feature of the mental number line.

Male mate guarding in a socially monogamous mammal, the round-eared sengi: on costs and trade-offs

Mate guarding is predicted to be one of the driving forces for the evolution of monogamy, but supporting evidence in free-living mammals is rare. The goals of our study were three-pronged. First, we tested if mate guarding, measured as intrapair distance, occurs as a behavioral tactic in round-eared sengis (Macroscelides proboscideus), a socially monogamous species lacking paternal care and in which females breed asynchronously, producing 2–3 litters during an 8-month long breeding season. Second, we determined if mate guarding involves costs which we identified as changes in male body mass. Third, we investigated whether variation in individual investment in mate guarding depended on the males’ body mass and the number of neighboring males. Field data were collected in a semidesert in South Africa using radio-tracking, trapping, and direct observations during three successive breeding seasons. Mate guarding strongly depended on the females’ reproductive state, and all males started to guard their mates prior to and during estrus, as exemplified by reduced intrapair distance. Mate guarding incurred costs: overall, males lost about 5% of body mass. Male body mass loss and initial body mass were negatively related to the intensity of precopulatory mate guarding. Furthermore, during estrus intrapair distance was inversely correlated with the number of neighboring males. The results show that mate guarding is the predominant male tactic in round-eared sengis. However, since mate guarding imposed costs, males may balance benefits and costs associated with guarding by varying their effort in relation to their physical capabilities and the competitive environment.

Genetic Architecture of Transcript-Level Variation in Humans

We report here the results of testing the pairwise association of 12,747 transcriptional gene-expression values with more than two million single-nucleotide polymorphisms (SNPs) in samples of European (CEPH from Utah; CEU) and African (Yoruba from Ibadan; YRI) ancestry. We found 4,677 and 5,125 significant associations between expression quantitative nucleotides (eQTNs) and transcript clusters in the CEU and the YRI samples, respectively. The physical distance between an eQTN and its associated transcript cluster was referred to as the intrapair distance. An association with 4 Mb or less intrapair distance was defined as local; otherwise, it was defined as distant. The enrichment analysis of functional categories shows that genes harboring the local eQTNs are enriched in the categories related to nucleosome and chromatin assembly; the genes harboring the distant eQTNs are enriched in the categories related to transmembrane signal transduction, suggesting that these biological pathways are likely to play a significant role in regulation of gene expression. We highlight in the EPHX1 gene a deleterious nonsynonymous SNP that is distantly associated with gene expression of ORMDL3, a susceptibility gene for asthma.

Migration Distances of Electrons Generated in Organic Solids by Ionizing Radiation

For estimating the final spatial resolution of lithography using ionizing radiation as a light source, the migration distances of electrons in γ-irradiated cryogenic organic matrices of polar alcohols and nonpolar methylcyclohexane have been determined by analyzing the transverse and the longitudinal electron spin−echo relaxations of radical pairs generated from the electrons and their counterpart cations. The intrapair distance of the radical pairs does not depend on the concentration of electron scavengers, which indicates that ejected electrons react with scavengers after losing their kinetic energies and being stabilized as trapped electrons. The intrapair distance decreases with increasing the concentration of polar molecules in the matrices, which indicates that charge−dipole interactions with polar molecules play significant roles in the slowing down process of the ejected electrons.

THE INFLUENCE OF SOCIAL ENVIRONMENT ON SEX DETERMINATION IN HARLEQUIN SHRIMP (HYMENOCERA PICTA: DECAPODA, GNATHOPHYLLIDAE)

Harlequin shrimp, Hymenocera picta, are monogamous and pair-bonding, and are usually found in isolated singles and pairs in the field. The apparent rarity of this species in their habitat and high levels of aggression between consexuals suggests the possibility of some sort of plasticity in their primary sex determination. In this study, the influence of social environment upon primary sex determination in H. picta was examined experimentally in the laboratory. Naive juveniles were placed in three novel social environments: paired juveniles, single juveniles, and adult/juvenile pairs. Spacing behavior and the onset of external differentiation were observed during long-term experiments for each social treatment. Gonadal development was also observed. Spacing behavior of paired shrimp reflected the sexual composition of social groups; high intrapair distance (IPD) for same-sex pairs and low IPD for opposite-sex pairs. Sex determination results were not so clear. Two of the three paired juvenile replicates displayed phenotype frequencies different from those expected from a random sample of gonochoristic organisms with a 1:1 sex ratio. However, the third replicate and the combined frequencies did not show any statistical difference from the hypothetical random sample. Furthermore, single juveniles and those paired with adults expressed sex in nearly 1:1 ratios, regardless of the sex of adult conspecifics. Histological examination of juvenile shrimp confirmed that sex was determined as early as four weeks after larval metamorphosis. Therefore, social environment had no clear effect upon sexual phenotype expressed. However, single females attained puberty at a significantly greater age and larger size than did females paired with males. Hence for H. picta, social environment had a measurable effect on the timing of female puberty. This is the first demonstration of this phenomenon in decapod Crustacea.

Thermaldissociation of chemisorbed oxygen molecules on Ag(110): aninvestigation by scanning tunnelling microscopy

The thermal dissociation of oxygen molecules on Ag(110) wasstudied by means of scanning tunnelling microscopy. Attemperatures around 170 K a fraction of the moleculesdissociate to form pairs of O atoms on the unreconstructed surface. The atoms lie in the trenches between the close-packedAg rows; the intrapair distance is two lattice constants. The Oatoms are very reactive with CO at temperatures as low as 70 K.The preferential orientation of the pairs in the [001] directioncontrasts with the finding in a previous study (Hahn J R,Lee H J and Ho W 2000 Phys. Rev. Lett. Vol. 85 1914)that electron-induced dissociation exclusively leads to [110]-oriented pairs. The trajectories of thermal andelectron-induced dissociations must therefore be different. Inthe temperature range of the dissociation, several additionaloxygen features occur on the surface. These include unreactedO2 molecules, the first nuclei of the added-row reconstruction, and two unidentified O-induced structures.

Low-temperature recombination kinetics of photoexcited persistent charge carriers in conjugated polymer/fullerene composite films

The recombination kinetics of long-lived photoexcited charge carriers in a composite of $\mathrm{poly}[2\ensuremath{-}\mathrm{methoxy}{\ensuremath{-}5\ensuremath{-}(3}^{\ensuremath{'}}{,7}^{\ensuremath{'}}\ensuremath{-}\mathrm{dimethyloctyloxy})\ensuremath{-}1,4\ensuremath{-}\mathrm{phenylene}$ vinylene] (MDMO-PPV) and $1\ensuremath{-}(3\ensuremath{-}\mathrm{methoxycarbonyl})\ensuremath{-}\mathrm{propyl}\ensuremath{-}1\ensuremath{-}\mathrm{phenyl}\ensuremath{-}(6,6){\mathrm{C}}_{61}$ (PCBM) at low temperatures $(T=40\mathrm{K})$ are investigated by light induced electron-spin resonance (LESR). These long-lived (persistent) photoinduced charge carriers exhibit recombination times that extend over several hours after cessation of the photoexcitation. These long relaxation times can be explained by nongeminate recombination of randomly distributed carriers assuming charge neutrality. The decay curves fit well to a model in which the recombination mechanism of photoexcited carriers consists of tunneling processes and in which the recombination rate only depends on the intrapair distance between the photoexcited carriers. It is shown that the residual photoexcited carrier concentration after long times tends to be independent of the generation rate. The presented model has already been successful in describing the recombination kinetics of photoexcited carriers in inorganic, amorphous semiconductors, which indicates that the presented recombination mechanism is common to disordered organic and inorganic materials.

Statistical Sulcal Shape Comparisons: Application to the Detection of Genetic Encoding of the Central Sulcus Shape

Principal Component Analysis allows a quantitative description of shape variability with a restricted number of parameters (or modes) which can be used to quantify the difference between two shapes through the computation of a modal distance. A statistical test can then be applied to this set of measurements in order to detect a statistically significant difference between two groups. We have applied this methodology to highlight evidence of genetic encoding of the shape of neuroanatomical structures. To investigate genetic constraint, we studied if shapes were more similar within 10 pairs of monozygotic twins than within interpairs and compared the results with those obtained from 10 pairs of dizygotic twins. The statistical analysis was performed using a Mantel permutation test. We show, using simulations, that this statistical test applied on modal distances can detect a possible genetic encoding. When applied to real data, this study highlighted genetic constraints on the shape of the central sulcus. We found from 10 pairs of monozygotic twins that the intrapair modal distance of the central sulcus was significantly smaller than the interpair modal distance, for both the left central sulcus (Z = −2.66; P < 0.005) and the right central sulcus (Z = −2.26; P < 0.05). Genetic constraints on the definition of the central sulcus shape were confirmed by applying the same experiment to 10 pairs of normal young individuals (Z = −1.39; Z = −0.63, i.e., values not significant at the P < 0.05 level) and 10 pairs of dizygotic twins (Z = 0.47; Z = 0.03, i.e., values not significant at the P < 0.05 level).

Recombination kinetics of long-lived carriers in a-Si:H at low temperatures

The recombination kinetics of long-lived photoexcited carriers in a-Si:H at low temperatures ( T∼50 K) are investigated by electron spin resonance. The carrier recombination kinetics over at least the first 30 min after cessation of the photoexcitation can be explained by non-geminate recombination of randomly distributed carriers assuming charge neutrality. The decay curves are well fit to a model in which the recombination rate only depends on the intra-pair distance of the photoexcited carriers and is independent of the specific slopes of the conduction and valence band tails. It is shown that the residual photoexcited carrier concentration after long times is independent of the generation rate.

Pair Interactions in Red-Faced Warblers

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

Excimer formation in pyrene crystals

The fluorescence of pyrene crystals shows a short-time component, called B-fluorescence, and a long-time component which is similar to the excimer fluorescence of pyrene solutions. Our model for the excimer creation is based on the pairwise arrangement of the molecules in the crystal. In the limiting case of vanishing intra-pair distance the electronic excitations of the crystal are symmetric and antisymmetric combinations of molecular excitations. The symmetric state that can be excited optically is identified with the B-state. The antisymmetric state is strongly localized and gives rise to the excimer fluorescence. The temperature dependence of the transition rate between the states is calculated analytically and is in good agreement with the experiment. The fluorescence spectra of the B-state and the excimer state are discussed.

Fast-ion transport mechanism in Li 3M 2(PO 4) 3 crystals (M ≡ Sc, Cr, Fe, In)

From experimental data on impedance, IR, Raman and nuclear magnetic resonance spectroscopy it is shown that each lithium ion moves by “classical” hopping in Li 3Sc 2(PO 4) 3 superionic crystals, i.e. the residence time τ ar is much greater than the time τ r of flight. At the same time the charge transfer in the compound can be “effectively” described as the motion of Li-Li ion pairs with an intrapair ion distance equal to approximately the sum of the lithium ion radii.

MAS NMR studies of silanol groups in zeolites ZSM-5 synthesized with an ionic template

1H magic angle spinning nuclear magnetic resonance (MAS NMR) measurements on ZSM-5 synthesized with tetrapropylammonium ions as structure-directing template, calcined and hydrogen exchanged, indicate high concentrations of silanol groups (up to 4.6×10 20 SiOH g −1). 1H NMR, 23Na and 29Si MAS NMR studies of zeolites ZSM-5 with different Si/Al ratios support a model which attributes the majority of these silanol groups to SiOH pairs located on the site of the removed TPA + cations with an intra-pair distance of 0.31 nm.

Ion-Ion Pairs in the Superionic Conductors

AbstractOn the base of numerous experimental data and theoretical approaches it is shown that ion-ion pairs with the intrapair distance about a sum of the corresponding ionic radii is the feature of charge transfer in the superionic conductors.

Eta pairing and off-diagonal long-range order in a Hubbard model.

It is shown in a simple Hubbard model that through a mechanism called \ensuremath{\eta} pairing one can construct many eigenstates of the Hamiltonian possessing off-diagonal long-range order. The intrapair distance is small. It is shown that these eigenstates are metastable and possess an energy gap.

The two-dimensional double layered antiferromagnetRb3Mn2Cl7—a neutron diffraction study

The structure of ${\mathrm{Rb}}_{3}$${\mathrm{Mn}}_{2}$${\mathrm{Cl}}_{7}$ is similar to that of ${\mathrm{Rb}}_{2}$Mn${\mathrm{Cl}}_{4}$. Whereas in ${\mathrm{Rb}}_{2}$Mn${\mathrm{Cl}}_{4}$ there are single Mn${\mathrm{Cl}}_{2}$ layers which are shifted one from the other by the (1/2,1/2,1/2) translation, in ${\mathrm{Rb}}_{3}$${\mathrm{Mn}}_{2}$${\mathrm{Cl}}_{7}$, instead of single layers there are pairs of layers. In the temperature range $64.5&lt;T&lt;100$ \ifmmode^\circ\else\textdegree\fi{}K the crystal behaves like a two-dimensional antiferromagnet. Its magnetic moments are oriented along the $c$ axis. Every moment is antiparallel to its five ${\mathrm{Mn}}^{+2}$ nearest neighbors. In this temperature range there are no correlations between the various pairs of layers. Therefore, instead of points in the reciprocal space one expects to obtain rods of reflections along ${c}^{*}$, as in the case of the single-layer type compounds. In the double-layer case, however, one expects the intensity of the rods to be modulated with a wave vector $\frac{2\ensuremath{\pi}}{t}$ where $t$ is the intrapair distance between layers. Several scans made along and across the ($0,1,l$) rods confirmed these expectations. Below ${T}_{N}\ensuremath{\sim}64.5$\ifmmode^\circ\else\textdegree\fi{}K the compound orders in three dimensions and as in ${\mathrm{Rb}}_{2}$Mn${\mathrm{Cl}}_{4}$ we find here (the same kind of) magnetic polytypism.