Asymptotic Mass Research Articles

No effect of the ectoparasite Crataerina pallida on reproduction of Common Swifts Apus apus

Previous studies have failed to ascertain negative effects of the Swift Lousefly Crataerina pallida parasitism on Common Swifts Apus apus. Abundances of C. pallida were experimentally manipulated to create broods experiencing either enhanced or reduced parasitism, and host life‐history traits were examined. No significant differences in clutch and brood size, rate of growth, asymptotic and fledging mass and size, or the number of fledglings per nest were observed. Reductions in parasite virulence may have developed due to the connection of C. pallida and host success, or costs may be borne by traits not influencing immediate fledging success.

ON THE ABSENCE OF PENTAQUARK STATES FROM DYNAMICS IN STRONGLY COUPLED LATTICE QCD

We consider an imaginary time functional integral formulation of a two-flavor, 3+1 lattice QCD model with Wilson's action and in the strong coupling regime (with a small hopping parameter, κ > 0, and a much smaller plaquette coupling, [Formula: see text], so that the quarks and glueballs are heavy). The model has local SU (3)c gauge and global SU (2)f flavor symmetries, and incorporates the corresponding part of the eightfold way particles: baryons (mesons) of asymptotic mass ≈-3 ln κ(≈-2 ln κ). We search for pentaquark states as meson–baryon bound states in the energy–momentum spectrum of the model, using a lattice Bethe–Salpeter equation. This equation is solved within a ladder approximation, given by the lowest nonvanishing order in κ and β of the Bethe–Salpeter kernel. It includes order κ2 contributions with a [Formula: see text] exchange potential together with a contribution that is a local-in-space, energy-dependent potential. The attractive or repulsive nature of the exchange interaction depends on the spin of the meson–baryon states. The Bethe–Salpeter equation presents integrable singularities, forcing the couplings to be above a threshold value for the meson and the baryon to bind in a pentaquark. We analyzed all the total isospin sectors, I = 1/2, 3/2, 5/2, for the system. For all I, the net attraction resulting from the two sources of interaction is not strong enough for the meson and the baryon to bind. Thus, within our approximation, these pentaquark states are not present up to near the free meson–baryon energy threshold of ≈-5 ln κ. This result is to be contrasted with the spinless case for which our method detects meson–baryon bound states, as well as for Yukawa effective baryon and meson field models. A physical interpretation of our results emerges from an approximate correspondence between meson–baryon bound states and negative energy states of a one-particle lattice Schrödinger Hamiltonian.

O-BTZ: Orientifolded BTZ black hole

Banados–Teitelboim–Zanelli (BTZ) black holes are constructed by orbifolding AdS3 geometry by boost transformations of its O(2,2) isometry group. Here we construct a new class of solutions to AdS3 Einstein gravity, orientifolded BTZ or O-BTZ for short, which in general, besides the usual BTZ orbifolding, involve orbifolding (orientifolding) by a Z2 part of O(2,2) isometry group. This Z2 is chosen such that it changes the orientation on AdS3 while keeping the orientation on its 2D conformal boundary. O-BTZ solutions exhaust all un-oriented AdS3 black hole solutions, as BTZ black holes constitute all oriented AdS3 black holes. O-BTZ, similarly to BTZ black holes, are stationary, axisymmetric asymptotically AdS3 geometries with two asymptotic charges, mass and angular momentum.

Fossil gas and the electromagnetic precursor of supermassive binary black hole mergers

Using a one-dimensional height integrated model, we calculate the evolution of an unequal mass binary black hole with a coplanar gas disk that contains a gap due to the presence of the secondary black hole. Viscous evolution of the outer circumbinary disk initially hardens the binary, while the inner disk drains onto the primary (central) black hole. As long as the inner disk remains cool and thin at low $\dot{M}_{\rm ext}$ (rather than becoming hot and geometrically thick), the mass of the inner disk reaches an asymptotic mass typically $\sim 10^{-3}-10^{-4}\Msun$. Once the semimajor axis shrinks below a critical value, angular momentum losses from gravitational waves dominate over viscous transport in hardening the binary. The inner disk then no longer responds viscously to the inspiraling black holes. Instead, tidal interactions with the secondary rapidly drive the inner disk into the primary. Tidal and viscous dissipation in the inner disk lead to a late time brightening in luminosity $L\propto t_{\rm minus}^{5/4}$, where $t_{\rm minus}$ is the time prior to the final merger. This late time brightening peaks $\sim 1$ day prior to the final merger at $\sim 0.1 L_{\rm Edd}$. This behavior is relatively robust because of self regulation in the coupled viscous-gravitational evolution of such binary systems. It constitutes a unique electromagnetic signature of a binary supermassive black hole merger and may allow the host galaxy to be identified if used in conjunction with the Laser Interferometric Space Antenna (LISA) localization.

Integrating elements and energy through the metabolic dependencies of gross growth efficiency and the threshold elemental ratio

Metabolic theory proposes that individual growth is governed through the mass- and temperature-dependence of metabolism, and ecological stoichiometry posits that growth is maximized at consumer-specific optima of resource elemental composition. A given consumer's optimum, the threshold elemental ratio (TER), is proportional to the ratio of its maximum elemental gross growth efficiencies (GGEs). GGE is defined by the ratio of metabolism-dependent processes such that GGEs should be independent of body mass and temperature. Understanding the metabolic-dependencies of GGEs and TERs may open the path towards a theoretical framework integrating the flow of energy and chemical elements through ecosystems. However, the mass and temperature scaling of GGEs and TERs have not been broadly evaluated. Here, we use data from 95 published studies to evaluate these metabolic-dependencies for C, N and P from unicells to vertebrates. We show that maximum GGEs commonly decline as power functions of asymptotic body mass and exponential functions of temperature. The rates of change in maximum GGEs with mass and temperature are relatively slow, however, suggesting that metabolism may not causally influence maximum GGEs. We additionally derived the theoretical expectation that the TER for C:P should not vary with body mass and this was supported empirically. A strong linear relationship between carbon and nitrogen GGEs further suggests that variation in the TER for C:N should be due to variation in consumer C:N. In general we show that GGEs may scale with metabolic rate, but it is unclear if there is a causal link between metabolism and GGEs. Further integrating stoichiometry and metabolism will provide better understanding of the processes governing the flow of energy and elements from organisms to ecosystems.

Nonminimal coupling for the gravitational and electromagnetic fields: Traversable electric wormholes

We discuss new exact solutions of a three-parameter nonminimal Einstein-Maxwell model. The solutions describe static spherically symmetric objects with and without center, supported by an electric field nonminimally coupled to gravity. We focus on a unique one-parameter model, which admits an exact solution for a traversable electrically charged wormhole connecting two universes, one asymptotically flat the other asymptotically de Sitter ones. The relation between the asymptotic mass and charge of the wormhole and its throat radius is analyzed. The wormhole solution found is thus a nonminimal realization of Wheeler's idea about charge without charge and shows that, if the world is somehow nonminimal in the coupling of gravity to electromagnetism, then wormhole appearance, or perhaps construction, is possible.

Embryo growth rates in birds and mammals

Summary 1. Embryo mass growth curves of 36 species of bird and 18 species of mammal were fitted by sigmoidal Gompertz functions, in which k (days−1) describes the rate at which the embryo approaches an asymptotic mass A (g). 2. The parameters of the Gompertz function were uncorrelated with parameters of power functions fitted to the same growth data, indicating that the two models describe different aspects of growth. 3. Asymptotes of the Gompertz functions for embryonic growth averaged 2·5 times neonate size, but were well below adult mass. Thus, the pre‐ and postnatal phases of growth are distinct and have different target sizes. 4. Embryo growth rate (k) decreases as the −1/4 power of neonate size; values for mammals were 63% of those of birds, on average. 5. Embryo growth rate can be predicted solely by the length of the incubation or gestation period, regardless of the size of the neonate, with the same relationship for birds and mammals. 6. Postnatal growth rate (kG) scales linearly with embryonic growth rate (k), but is nearly five‐ times more rapid, on average, in birds than in mammals. kG and k have similar magnitude in birds, but kG is relatively much slower than k in mammals. 7. Rate of actuarial senescence ω (year−1), measured by the increase in mortality rate with age, is positively related to the rate of embryo growth in both birds and mammals, but is higher in the latter. Moreover, rate of ageing in birds is uniquely related to embryo growth while that in mammals is uniquely related to postnatal growth rate. Thus, development and ageing appear to be differently connected in birds and mammals, although the basis for these relationships is not known.

Scalar hairs and exact vortex solutions in 3D AdS gravity

We investigate three-dimensional (3D) Anti-de Sitter (AdS) gravity coupled to a complex scalar field ϕ with self-interaction potential V (|ϕ|). We show that the mass of static, rotationally symmetric, AdS black hole with scalar hairs is determined algebraically by the scalar charges. We recast the field equations as a linear system of first order differential equations. Exact solutions, describing 3D AdS black holes with real spherical scalar hairs and vortex-black hole solutions are derived in closed form for the case of a scalar field saturating the Breitenlohner-Freedman (BF) bound and for a scalar field with asymptotic zero mass. The physical properties of these solutions are discussed. In particular, we show that the vortex solution interpolates between two different AdS3 vacua, corresponding respectively to a U(1)-symmetry-preserving maximum and to a symmetrybreaking minimum of the potential V.

A giant dusty bipolar structure around the planetary nebula NGC 1514

The transition from spherically symmetric asymptotic giant branch mass loss to aspherical planetary nebulae is an intriguing problem of stellar astrophysics. On 12 μm maps of the Infrared Astronomical Satellite (IRAS), we detected a huge (2.6 pc) dust emission region around the evolved planetary nebula NGC 1514. On 100 and 60 μm IRAS maps, we additionally found two giant (2.1 and 0.9 pc) bipolar dust emission structures centred on NGC 1514; we suspect that each of these regions is physically connected to the planetary nebula. The bipolar structures are slightly tilted with respect to each other, possibly due to precession. The total mass (dust + gas) of all structures is 2.2 ± 1.4 M ⊙ . We argue that NGC 1514 and its dusty surroundings represent one of the very few known cases where the preserved history of all main mass-loss phases of a star of intermediate initial mass can be seen.

Fragmentation and restructuring of soft-agglomerates under shear

Soft-agglomerate restructuring, break-up (or fragmentation) and relaxation are studied in a simple shear flow by a discrete element method (DEM). The agglomerates, held together by van der Waals forces, rotate in the shear flow and are stretched into nearly linear structures (fractal dimension approaches unity) until they fracture at their weakest point resulting in lognormally-shaped fragment size distributions asymptotically. Individual fragments relax in the flow towards more compact agglomerates than the parent ones. The evolution of the average number of particles per fragment is described by generalized scaling laws between shear rate, onset (time-lag) of fragmentation, asymptotic fragment mass and size consistent with experimental and theoretical studies in the literature. The initial effective fractal dimension of the agglomerates influences the final one of the fragments.

Sex-specific Growth in Alpine Chamois

Studying between-sex differences in body growth has strong implications for understanding life-history tactics of animals. We used age and carcass mass data from 2,312 female and 2,622 male alpine chamois (Rupicapra rupicapra) harvested in the French Alps to model the sex-specific body growth patterns of this species. Males were heavier (asymptotic body mass: 29.6 kg) than females (22.3 kg), with an adult sexual size dimorphism of 32.4%. Sexual size dimorphism originated from both differences in body growth after 1.5 years of age and differences in length of the growth period. Females reached asymptotic body mass almost 3 years earlier (3.5 years) than males (6.2 years). We also found that females 1st reproduced before achieving asymptotic growth, at 78% of their asymptotic body mass. Between-sex differences in growth patterns in this species are most likely due to stronger selection pressure for larger size in males than in females due to intrasexual competition.

Instability of charged wormholes supported by a ghost scalar field

In previous work, we analyzed the linear and nonlinear stability of static, spherically symmetric wormhole solutions to Einstein's field equations coupled to a massless ghost scalar field. Our analysis revealed that all these solutions are unstable with respect to linear and nonlinear spherically symmetric perturbations and showed that the perturbation causes the wormholes to either decay to a Schwarzschild black hole or undergo a rapid expansion. Here, we consider charged generalization of the previous models by adding to the gravitational and ghost scalar field an electromagnetic one. We first derive the most general static, spherically symmetric wormholes in this theory and show that they give rise to a four-parameter family of solutions. This family can be naturally divided into subcritical, critical and supercritical solutions depending on the sign of the sum of the asymptotic masses. Then, we analyze the linear stability of these solutions. We prove that all subcritical and all critical solutions possess one exponentially in time growing mode. It follows that all subcritical and critical wormholes are linearly unstable. In the supercritical case we provide numerical evidence for the existence of a similar unstable mode.

EXACT DYNAMICAL EIGHTFOLD WAY BARYON SPECTRUM AND CONFINEMENT IN STRONGLY COUPLED LATTICE QCD

We obtain from the quark–gluon dynamics the eightfold way baryon spectrum exactly in an imaginary time functional integral formulation of 3+1 lattice QCD with Wilson's action in the strong coupling regime (small hopping parameter 0 < κ ≪ 1 and much smaller plaquette coupling [Formula: see text]). The model has SU(3)c local gauge and global SU(3)f flavor symmetries. A decoupling of the hyperplane method naturally unveils the form of the baryon composite fields. In the subspace of the physical Hilbert space of vectors with an odd number of quarks, the baryons are associated with isolated dispersion curves in the energy–momentum spectrum. Spectral representations are derived for the two-baryon correlations, which allow us to detect the energy–momentum spectrum and particles as complex momentum space singularities. The spin 1/2 octet and spin 3/2 decuplet baryons have asymptotic mass -3ln κ and for each baryon there is an antibaryon with identical spectral properties. An auxiliary function method is used to obtain convergent expansions for the masses after subtracting the singular part -3ln κ. The nonsingular part of the mass is analytic in κ and β, i.e. the expansions are controlled to all orders. For β = 0, all the masses have the form M = -3ln κ - 3κ3/4 + κ6r(κ), with r(κ) real analytic. Although we have no Lorentz symmetry in our lattice model, we show that there is a partial restoration of the continuous rotational symmetry at zero spatial momentum, which implies that for all members of the octet (decuplet) r(κ) is the same. So, there is no mass splitting within the octet and within the decuplet. However, there is an octet–decuplet mass difference of [Formula: see text] at β = 0; the splitting persists for β ≠ 0. We also obtain the (anti)baryon dispersion curves which admit the representation [Formula: see text], where [Formula: see text] and [Formula: see text] is of [Formula: see text]. For the octet, [Formula: see text] is jointly analytic in κ and in each pj, for small [Formula: see text]. A new local symmetry, which we call spin flip, is used to establish constraints for the matrix-valued two-baryon correlation and show that all the octet dispersion curves are the same and that the four decuplet dispersion curves are pairwise-identical and depend only on the modulus of the spin z-component. Using a correlation subtraction method we show that the spectrum generated by the baryon and antibaryon fields is the only spectrum, in the odd quark subspace of physical states, up to near the baryon–meson threshold of ≈ -5ln κ. Combining this result with a similar result for the mesons, with mass ≈ -2ln κ, shows that the only spectrum in the entire space of states, up to near the two-meson threshold of ≈ -4ln κ, is generated by the eightfold way hadrons. Hence, for 0 < κ ≪ β ≪ 1, we have shown confinement up to near this threshold.

Growth of Male White-Tailed Deer: Consequences of Maternal Effects

Identifying maternal effects on offspring is critical to interpreting population dynamics, but the duration of maternal effects and which life-history traits they influence is not well understood. We quantified growth and development of male white-tailed deer (Odocoileus virginianus) originating from the Black Hills in southwestern South Dakota and from eastern South Dakota in a controlled environment with high-quality nutrition. Despite being in good nutritional condition, males from the Black Hills ceased rapid growth 41 days earlier, were 29% smaller at asymptotic body mass, and grew significantly smaller antlers than males from eastern South Dakota. Females from eastern South Dakota were 14.9 kg larger than females from the Black Hills, yet birth mass of male offspring was similar for females from the 2 regions. Male offspring of 1stgeneration deer from the Black Hills attained a 30% larger asymptotic body mass and grew significantly larger antlers than their sires. Body mass and antler size of 2nd-generation males of Black Hills origin approached that of 1st-generation males from eastern South Dakota at maturity. Suppression in growth of 1st-generation males of the Black Hills and increased growth by their offspring supported an influence of maternal and grandmaternal condition during gestation on subsequent growth of offspring and highlighted the significance of nutrition during gestation. These intergenerational effects indicate that measures of animal condition and population performance might reflect past rather than current conditions, and illustrate the potential for time lags in responses of populations to improved environmental conditions.

Foraging decisions in a capital breeder: trade-offs between mass gain and lactation

The high energetic costs of lactation can lead to fundamental trade-offs in life-history traits, particularly in young females that reproduce before completing body growth. We assessed whether lactating female mountain goats (Oreamnos americanus) used behavioural tactics at fine spatio-temporal scales to increase energy intake to compensate for the costs of lactation. Lactating females increased bite rate and chewing rate compared with non-lactating females, but selected similar foraging sites in terms of plant quality and abundance. At peak lactation, forage intake of lactating females was >40% greater than that of non-lactating females. For females that had reached asymptotic body mass (i.e. > or =6 years old), summer mass gain of lactating females was similar to that of non-lactating females. At 4 and 5 years of age, however, daily mass gain of lactating females was about 20% lower than that of non-lactating females. We conclude that increased foraging may allow fully-grown lactating females to compensate for the energetic costs of lactation, but that there is a major trade-off between mass gain and lactation for younger females.

High-energy supersymmetry at finite temperature

We study the leading thermal corrections to various observables in the high-energy limit in supersymmetric theories and observe that they preserve supersymmetry. Our findings generalize previous observations on the equality of asymptotic thermal masses in weakly coupled plasmas. We observe supersymmetry in the leading thermal effects for both the real and imaginary parts of self-energies, on the light cone and away from it, in both weakly and strongly interacting theories. All observed supersymmetry violations are found to be suppressed by more than two powers of the (large) energy.

Quark mass dependence of thermal excitations in QCD in one-loop approximation

A comprehensive determination of the quark mass dependence in the dispersion relations of thermal excitations of gluons and quarks in non-Abelian gauge theory (QCD) is presented for the one-loop approximation in the Feynman gauge. Larger values of the coupling are admitted, and some aspects of the gauge dependence are discussed. In a Dyson–Schwinger type approach, the effect of higher orders is estimated for asymptotic thermal masses.

Long-lasting consequences of elevated yolk testosterone levels on female reproduction

Maternal yolk androgens in bird eggs represent an important pathway along which offspring phenotype is shaped. Most of the hormone-mediated maternal effects are highly important in the context of sibling competition. However, there is also increasing evidence for long-lasting effects far beyond the nestling period, and these effects may have important consequences on the reproductive success of the offspring. Here, we investigated the effects of experimentally elevated yolk testosterone concentrations on growth and reproduction in female canaries. Elevated yolk testosterone concentrations enhanced the post-natal growth rate, but not the asymptotic mass, and reduced the survival probability. The latter may be a consequence of the higher growth rate, which may have rendered females hatching from testosterone-treated eggs (T-females) more vulnerable to harsh environmental conditions. Adult T-females made a larger investment in their clutch by laying more but not heavier eggs than females hatching from control-treated eggs. Our results suggest that the observed long-lasting effect on clutch size relates to changes in the growth trajectory rather than being a direct consequence of testosterone, since studies manipulating early growth conditions obtained similar results. Clearly, further studies are now required in order to investigate the intriguing relationship between yolk testosterone, elevated growth rates, and clutch size.

Exact Mesonic Eightfold Way From Dynamics and Confinement in Strongly Coupled Lattice QCD

We review our results on the exact determination of the mesonic eightfold way from first principles, directly from the quark-gluon dynamics. For this, we consider an imaginary-time functional integral formulation of 3 + 1 dimensional lattice QCD with Wilson action, three flavors, SU(3)f flavor symmetry and SU(3)c local gauge symmetry. We work in the strong coupling regime: a small hopping parameter κ > 0 and a much smaller plaquette coupling β > 0 . By establishing a Feynman-Kac formula and a spectral representation to the two-meson correlation, we provide a rigorous connection between this correlation and the one-meson energy-momentum spectrum. The particle states can be labeled by the usual SU(3)f quantum numbers of total isospin I and its third-component I3, the quadratic Casimir C2 and, by a partial restoration of the continuous rotational symmetry on the lattice, as well as by the total spin J and its z–component Jz. We show that, up to near the two-meson energy threshold of ≈ − 4 ln κ , the spectrum in the meson sector is given only by isolated dispersion curves of the eightfold way mesons. The mesons have all asymptotic mass of − 2 ln κ and, by deriving convergent expansions for the masses both in κ and β, we also show a κ 4 mass splitting between the J = 0 , 1 states. The splitting persists for β ≠ 0 . Our approach employs the decoupling of hyperplane method to uncover the basic excitations, complex analysis to determine the dispersion curves and a correlation subtraction method to show the curves are isolated. Using the latter and recalling our similar results for baryons, we also show confinement up to near the two-meson threshold.

Parental allocation of additional food to own health and offspring growth in a variable environment

Life-history theory predicts increased investment in current reproduction when future reproduction is uncertain and a more balanced investment in current and future reproduction when prospects for both are good. The outcome of the balance in parental allocation depends on which life-history component maximizes the fitness benefits. In our study system, a 3-year vole cycle generates good prospects of current and future reproduction for Ural owls ( Strix uralensis Pallas, 1771) in increase vole phases and uncertain prospects in decrease vole phases. We supplementary-fed Ural owls during the nestling period in 2002 (an increase phase) and 2003 (a decrease phase), and measured offspring growth, parental effort, and physiological health by monitoring haematocrit, leucocyte profiles, intra- and inter-celluar blood parasites, and (in 2003) humoral antibody responsiveness. Food supplementation reduced parental feeding rate in both years, but improved a female parent’s health only in 2002 (an increase phase) and had no effects on males in either year. Nevertheless, supplementary-fed offspring reached higher asymptotic mass and fledged earlier in both years. Furthermore, early fledging reduced offspring exposure to blood-sucking black flies (Diptera, Simuliidae) in the nest. We discuss how parental allocation of resources to current and future reproduction may vary under variable food conditions.