Experimental demonstration that offspring fathered by old males have shorter telomeres and reduced lifespans

Offspring of older parents frequently show reduced longevity, but the mechanisms driving this so-called 'Lansing effect' are unknown. While inheritance of short telomeres from older parents could underlie this effect, studies to date in different species have found mixed results, reporting positive, negative or no association between parental age and offspring telomere length (TL). However, most of the existing evidence is from non-experimental studies in which it is difficult to exclude alternative explanations such as differential survival of parents with different telomere lengths. Here we provide evidence in the zebra finch that offspring from older parents have reduced lifespans. As a first step in disentangling possible causes, we used an experimental approach to examine whether or not we could detect pre-natal paternal effects on offspring TL. We found that zebra finch embryos fathered by old males have shorter telomeres than those produced by the same mothers but with younger fathers. Since variation in embryonic TL persists into post-natal life, and early life TL is predictive of longevity in this species, this experimental study demonstrates that a paternally driven pre-natal TL reduction could at least in part underlie the reduced lifespan of offspring from older parents

Modulation Doping near Mott-Insulator Heterojunctions

We argue that interesting strongly correlated two-dimensional electron systems can be created by modulation doping near a heterojunction between Mott insulators. Because the dopant atoms are remote from the carrier system, the electronic system will be weakly disordered. We argue that the competition between different ordered states can be engineered by choosing appropriate values for the dopant density and the setback distance of the doping layer. In particular larger setback distances favor two-dimensional antiferromagnetism over ferromagnetism. We estimate some key properties of modulation-doped Mott insulator heterojunctions by combining insights from Hartree-Fock-Theory and Dynamical-Mean-Field-Theory descriptions and discuss potentially attractive material combinations.Comment: 9 pages, 9 figures, submitte

Structural properties and quasiparticule energies of cubic SrO, MgO and SrTiO3

The structural properties and the band structures of the charge-transfer insulating oxides SrO, MgO and SrTiO3 are computed both within density functional theory in the local density approximation (LDA) and in the Hedin's GW scheme for self-energy corrections, by using a model dielectric function, which approximately includes local field and dynamical effects. The deep valence states are shifted by the GW method to higher binding energies, in very good agreement with photoemission spectra. Since in all of these oxides the direct gaps at high-symmetry points of the Brillouin zone may be very sensitive to the actual value of the lattice parameter a, already at the LDA level, self-energy corrections are computed both at the theoretical and the experimental a. For MgO and SrO, the values of the transition energies between the valence and the conduction bands are improved by GW corrections, while for SrTiO3 they are overestimated. The results are discussed in relation to the importance of local field effects and to the nature of the electronic states in these insulating oxides.Comment: 3 figures, accepted in J. Phys.: Condens. Matte

A portrait of trade in value added over four decades

We combine data on trade, production, and input use to document changes in the value added content of trade between 1970 and 2009. The ratio of value-added to gross exports fell by roughly 10 percentage points worldwide. The ratio declined 20 percentage points in manufacturing, but rose in non-manufacturing sectors. Declines also differ across countries and trade partners: they are larger for fast growing countries, for nearby trade partners, and among partners that adopt regional trade agreements. Using a multi-sector structural gravity model with input-output linkages, we show that changes in trade frictions play a dominant role in explaining all these facts

The eta-photon transition form factor

The eta-photon transition form factor is evaluated in a formalism based on a phenomenological description at low values of the photon virtuality, and a QCD-based description at high photon virtualities, matching at a scale $Q_{0}^{2}$. The high photon virtuality description makes use of a Distribution Amplitude calculated in the Nambu-Jona-Lasinio model with Pauli-Villars regularization at the matching scale $Q_{0}^{2}$, and QCD evolution from $Q_{0}^{2}$ to higher values of $Q^{2}$. A good description of the available data is obtained. The analysis indicates that the recent data from the BaBar collaboration on pion and eta transition form factor can be well reproduced, if a small contribution of twist three at the matching scale $Q_{0}^{2}$ is included.Comment: 14 pages, 3 figures, revised version, minor corrections, references added, conclusions unchanged. Accepted for publication in Phys. Rev.

Model analysis of the world data on the pion transition form factor

We discuss the impact of recent Belle data on our description of the pion transition form factor based on the assumption that a perturbative formalism and a nonperturbative one can be matched in a physically acceptable manner at a certain hadronic scale $Q_{0}$. We discuss the implications of the different parameters of the model in comparing with world data and conclude that within experimental errors our description remains valid. Thus we can assert that the low $Q^2$ nonperturbative description together with an additional $1/Q^2$ term at the matching scale have a strong influence on the $Q^2$ behavior up to very high values of $Q^2$ .Comment: 6 pages and 3 figures. Contains a comparison with other models and additional reference

MAXIMALITY OF LOGIC WITHOUT IDENTITY

Lindström’s theorem obviously fails as a characterization of first-order logic without identity ( L − ωω ). In this note, we provide a fix: we show that L − ωω is a maximal abstract logic satisfying a weak form of the isomorphism property (suitable for identity-free languages and studied in [11]), the Löwenheim–Skolem property, and compactness. Furthermore, we show that compactness can be replaced by being recursively enumerable for validity under certain conditions. In the proofs, we use a form of strong upwards Löwenheim–Skolem theorem not available in the framework with identity

Magnetism and half-metallicity at the O surfaces of ceramic oxides

The occurence of spin-polarization at ZrO$_{2}$, Al$_{2}$O$_{3}$ and MgO surfaces is proved by means of \textit{ab-initio} calculations within the density functional theory. Large spin moments, as high as 1.56 $\mu_B$, develop at O-ended polar terminations, transforming the non-magnetic insulator into a half-metal. The magnetic moments mainly reside in the surface oxygen atoms and their origin is related to the existence of $2p$ holes of well-defined spin polarization at the valence band of the ionic oxide. The direct relation between magnetization and local loss of donor charge makes possible to extend the magnetization mechanism beyond surface properties

On completeness results for predicate lukasiewicz, product, gödel and nilpotent minimum logics expanded with truth-constants

In this paper we deal with generic expansions of first-order predicate logics of some left-continuous t-norms with a countable set of truth-constants. Besides already known results for the case of Lukasiewicz logic, we obtain new conservativeness and completeness results for some other expansions. Namely, we prove that the expansions of predicate Product, Gödel and Nilpotent Minimum logics with truth-constants are conservative, which already implies the failure of standard completeness for the case of Product logic. In contrast, the expansions of predicate Gödel and Nilpotent Minimum logics are proved to be strong standard complete but, when the semantics is restricted to the canonical algebra, they are proved to be complete only for tautologies. Moreover, when the language is restricted to evaluated formulae we prove canonical completeness for deductions from finite sets of premises.Peer Reviewe

Stress exposure in early post-natal life reduces telomere length: an experimental demonstration in a long-lived seabird

Exposure to stressors early in life is associated with faster ageing and reduced longevity. One important mechanism that could underlie these late life effects is increased telomere loss. Telomere length in early post-natal life is an important predictor of subsequent lifespan, but the factors underpinning its variability are poorly understood. Recent human studies have linked stress exposure to increased telomere loss. These studies have of necessity been non-experimental and are consequently subjected to several confounding factors; also, being based on leucocyte populations, where cell composition is variable and some telomere restoration can occur, the extent to which these effects extend beyond the immune system has been questioned. In this study, we experimentally manipulated stress exposure early in post-natal life in nestling European shags (Phalacrocorax aristotelis) in the wild and examined the effect on telomere length in erythrocytes. Our results show that greater stress exposure during early post-natal life increases telomere loss at this life-history stage, and that such an effect is not confined to immune cells. The delayed effects of increased telomere attrition in early life could therefore give rise to a ‘time bomb’ that reduces longevity in the absence of any obvious phenotypic consequences early in life