pinecone/core-2020-05-10-deduplication huggingface dataset:
Foraging Site Displacement in Common Crane Flocks

Optimal foraging theory predicts that an individual should resort to intraspecific kleptoparasitism when this foraging strategy helps to maximize its intake rate. Thus aggressor and victim should be foraging at\ud
lower and higher rates, respectively, than the flock average (intake rate maximization). Independent of the maximization principle, moreover, an aggressor should attack when its intake rate falls below a threshold critical for survival, and select a victim foraging at an intake rate high enough to ensure survival\ud
(starvation risk minimization). We tested both hypotheses using 324 aggressive displacements from feeding sites observed in flocks of common cranes, Grus grus, foraging on cereal fields. Aggressors attacked cranes feeding at higher rates than average birds. The immediate consequences of a successful attack were an increase in intake rate for the aggressor and a decrease for the victim. The intake rate of the aggressor prior to the attack was lower than both the mean intake rate of the flock and the minimum intake rate necessary to cover basic metabolic needs. After displacing its victim, the intake rate of the aggressor was\ud
higher than before the attack and also higher than the average intake rate of the flock. The intake rate of the aggressor after the attack was not higher than the mean intake rate of the flock, however, when the time spent on the attack was included. We conclude that cranes used a kleptoparasitic strategy to recover\ud
from temporary reductions in feeding rate. This was particularly the case below the threshold of intake necessary for survival.We thank Anders Berglund, Ken Norris and an anonymous referee for their helpful comments and suggestions which significantly improved the manuscript. This is a contribution to project PB91-0081 of the Dirección General de Investigación Científica y Técnica.Peer reviewe
Male vocalization and female choice in the hybridogenetic Rana lessonae/Rana esculenta complex

In many species, females can improve their fitness by preferring particular males over others. In\ud
Palaearctic water frogs of the Rana lessonae/R. esculenta complex the consequences of such mate choice are particularly pronounced. To produce viable offspring, the hybrid R. esculenta (genotype RL) must mate with the parental species R. lessonae (LL); but R. lessonae should avoid mating with R. esculenta, because the resulting hybrid offspring will eliminate the L genome from the germline (hybridogenesis). Hence, there exists a conflict between the sexual parasite (RL) and its sexual host (LL) over the best mating partner. Previous studies have shown a preference for LL males in LL and RL females; but they have also\ud
shown that females cannot usually realize their choice when in close proximity to males, because the males forcefully and indiscriminately amplex them. We tested whether females use male vocalizations as a long-distance signal to increase their chances of mating with the preferred LL males. We exposed female R. lessonae and R. esculenta to playbacks of single LL and RL mating calls (experiment 1) and to choruses\ud
with a 3:1 excess of LL and RL calls, respectively (experiment 2). In experiment 1, both female types were attracted more by the LL than by the RL calls. In experiment 2, no discrimination between LL- and RL-dominated choruses was observed. The results suggest that females do not use distant male vocalization to approach preferentially ponds or arenas within a pond that hold an excess of LL males. But once they have arrived in a chorus, mating calls from nearby males can direct them to the preferred LL mates. We discuss possible reasons for the failure to discriminate between choruses and the chances for successful choice between individuals within choruses
Secretions of the interaural gland contain information about individuality and colony membership in the Bechstein’s bat.

Mammals use chemical signals for individual and kin recognition, to establish social hierarchies, mark territories and choose mates. The nocturnal and social lifestyle of bats suggests that, besides acoustic signals, they also use scent to communicate. We investigated in the communally breeding Bechstein’s bat, Myotis bechsteinii, whether secretions of the facial interaural gland contain information that can be used for individual and colony recognition. Since female Bechstein’s bats live in closed societies and show cooperative behaviour, we predicted they would recognize colony members. We analysed interaural gland secretions, which we repeatedly sampled from 85 females belonging to four free-ranging colonies. Gas chromatography/mass spectrometry profiles were individually specific and differed between colonies.\ud
Comparing odour profiles between colonies we found a relation between chemical similarity and the mitochondrial haplotype of colony members. Within colonies there was no correlation between mass spectrometer profile similarity and genetic relatedness. Our results suggest that female Bechstein’s bats may use interaural gland secretions for individual and colony recognition but not to infer kinship directly
A process of pair formation leading to assortative mating: Passive age-assortative mating by habitat heterogeneity

We present an individual-based model dealing with mating as a process of pair formation. Model simulations, based on data from a 19-year study of Spanish imperial eagles, Aquila adalberti, showed that the mating pattern of a population is not necessarily a direct consequence of the mating preferences of individuals; positive age-assortative mating, by which individuals of similar age are more likely to become paired, does not necessarily indicate homotypic mating preferences. For example, individuals of similar, young age may be constrained to a few low-quality territories, leading to passive assortative mating, independent of individual preferences. Confounding factors such as territory quality can affect the encounters between a male and a female available for mating, generating an age-assortative mating totally independent of mate preferences. Such a process may apply to many territorial species when spatial variation in territory quality is pronounced. © 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.Peer Reviewe
The Fossil Record of the Epacridaceae

Fossil pollen and macrofossils of Epacridaceae are uncommon and are mainly known from Tasmania and other parts of south-eastern Australia.  Most epacrids have generalised ericalean pollen although the pollen of some genera is distinctive.  Ericalean pollen is known from the late Cretaceous.  The first occurrence of Paripollis orchesis pollen, which is consistent with some extant Epacris species, probably means that Epacridaceae, and possibly the tribe Epacrideae, had differentiated by the Middle Eocene.\ud
The fossil record at present provides minimum ages of the first occurrences of major subfamilial taxa.  Macrofossils of subfamily Richeoideae and of several morphotypes of the tribe Epacrideae are known from the Early Oligocene.  Tribe Cosmelieae pollen and macrofossils are known from the Early Pleistocene, and are probably Sprengelia.  The oldest Australasian fossils of tribe Styphelieae are leaves in latest Oligocene-Early Miocene parts of the Latrobe Valley coal.  Endocarps identified as Epacridaceae from the Eocene of England need further investigation.  Pollen of Monotoca, or a close relative, is known from the mid-Miocene.  Possible Trochocarpa leaves occur in Late Oligocene/Early Miocene sediments, and fossil leaves indistinguishable from the extant Tasmanian rainforest species, T. gunnii and T. cunninghamii, are known from the Early Pleistocene in Tasmania
Application of the functional-structural tree model LIGNUM to sugar maple saplings (Acer saccharum Marsh) growing in forest gaps

LIGNUM is a functional-structural model that represents a tree using four modelling units which closely resemble the real structure of trees: tree segments, tree axes, branching points and buds. Metabolic processes are explicitly related to the structural units in which they take place. Here we adapt earlier versions of LIGNUM designed to model growth of conifers for use with broad-leaved trees. Two primary changes are involved. First, the tree segment for broad-leaved trees consists of enclosed cylinders of heartwood, sapwood and bark. Leaves consisting of petioles and blades are attached to the segments. Secondly, axillary buds and rules governing their dormancy are included in the model. This modified version of LIGNUM is used to simulate the growth and form of sugar maple saplings in forest gaps. The annual growth of the model tree is driven by net production after respiration losses are taken into account. The production rate of each leaf depends on the amount of photosynthetically active radiation it receives. The radiation regime is tracked explicitly in different parts of the tree crown using a model of mutual shading of the leaves. Forest gaps are represented by changing the radiation intensity in different parts of the model sky. This version of LIGNUM modified for use with broad-leaf, deciduous trees and parameterized for sugar maple, yields good simulations of growth and form in saplings from different forest gap environments
A Comprehensive Coordinate Space Renormalization of Quantum
  Electrodynamics to 2-Loop Order

We develop a coordinate space renormalization of massless Quantum
Electrodynamics using the powerful method of differential renormalization. Bare
one-loop amplitudes are finite at non-coincident external points, but do not
accept a Fourier transform into momentum space. The method provides a
systematic procedure to obtain one-loop renormalized amplitudes with finite
Fourier transforms in strictly four dimensions without the appearance of
integrals or the use of a regulator. Higher loops are solved similarly by
renormalizing from the inner singularities outwards to the global one. We
compute all 1- and 2-loop 1PI diagrams, run renormalization group equations on
them and check Ward identities. The method furthermore allows us to discern a
particular pattern of renormalization under which certain amplitudes are seen
not to contain higher-loop leading logarithms. We finally present the
computation of the chiral triangle showing that differential renormalization
emerges as a natural scheme to tackle $\gamma_5$ problems.Comment: 28 pages (figures not included
Landau, Abrikosov, Hofstadter: Magnetic Flux Penetration in a Lattice
  Superconductor

Magnetic flux penetration in superconductors involves a rich variety of
subtle phenomena, much of which is still poorly understood. Here these
complexities are studied by formulating the Ginzburg-Landau equations as a
lattice gauge theory. Their solutions are compared and contrasted with the
(heuristic) Landau model of type I superconductivity, and the (perturbative)
Abrikosov model for type II superconductors. Novelties arise as the continuum
limit is approached, related to an effect discovered by Hofstadter. Various
cautionary remarks pertinent to large-scale simulations are made
Duality, Quantum Vortices and Anyons in Maxwell-Chern-Simons-Higgs
  Theories

The order-disorder duality structure is exploited in order to obtain a
quantum description of anyons and vortices in: a) the Maxwell theory; b) the
Abelian Higgs Model; c) the Maxwell-Chern-Simons theory; d) the
Maxwell-Chern-Simons-Higgs theory. A careful construction of a charge bearing
order operator($\sigma$) and a magnetic flux bearing disorder operator (vortex
operator) ($\mu$) is performed, paying attention to the necessary requirements
for locality. An anyon operator is obtained as the product $\varphi=\sigma\mu$.
A detailed and comprehensive study of the euclidean correlation functions of
$\sigma$, $\mu$ and $\varphi$ is carried on in the four theories above. The
exact correlation functions are obtained in cases $\underline{a}$ and
$\underline{c}$. The large distance behavior of them is obtained in cases
$\underline{b}$ and $\underline{d}$. The study of these correlation functions
allows one to draw conclusions about the condensation of charge and magnetic
flux, establishing thereby an analogy with the Ising model. The mass of vortex
and anyon excitations is explicitly obtained wherever these excitations are
present in the spectrum. The independence between the mechanisms of mass
generation for the vortices and for the vector field is clearly exposed.Comment: 58 pages; 6 figures (available from the author upon request); Latex;
  Princeton report PUPT-133
The phase-space structure of the Klein-Gordon field

The formalism based on the equal-time Wigner function of the two-point
correlation function for a quantized Klein--Gordon field is presented. The
notion of the gauge-invariant Wigner transform is introduced and equations for
the corresponding phase-space calculus are formulated. The equations of motion
governing the Wigner function of the Klein--Gordon field are derived. It is
shown that they lead to a relativistic transport equation with electric and
magnetic forces and quantum corrections. The governing equations are much
simpler than in the fermionic case which has been treated earlier. In addition
the newly developed formalism is applied towards the description of spontaneous
symmetry breakdown.Comment: 27 pages, LaTeX, UFTP 317/199
The Classical and Quantum Mechanics of Lazy Baker Maps

We introduce and study the classical and quantum mechanics of certain non
hyperbolic maps on the unit square. These maps are modifications of the usual
baker's map and their behaviour ranges from chaotic motion on the whole measure
to chaos on a set of measure zero. Thus we have called these maps ``lazy baker
maps.'' The aim of introducing these maps is to provide the simplest models of
systems with a mixed phase space, in which there are both regular and chaotic
motions. We find that despite the obviously contrived nature of these maps they
provide a good model for the study of the quantum mechanics of such systems. We
notice the effect of a classically chaotic fractal set of measure zero on the
corresponding quantum maps, which leads to a transition in the spectral
statistics. Some periodic orbits belonging to this fractal set are seen to scar
several eigenfunctions.Comment: 27 pages, LaTex file. Figures not included, but available upon
  request. To appear in Sept. issue of Annals of Physic
Dynamical instability criterion for circular (vorton) string loops

Dynamic perturbation equations are derived for a generic stationary state of
an elastic string model -- of the kind appropriate for representing a
superconducting cosmic string -- in a flat background. In the case of a
circular equilibrium (i.e. vorton) state of a closed string loop it is shown
that the fundamental axisymmetric ($n=0$) and lowest order ($n=1$)
nonaxisymmetric perturbation modes can never be unstable. However, stability
for modes of higher order ($n\geq 2$) is found to be non-trivially dependent on
the values of the characteristic propagation velocity, $c$ say, of longitudinal
perturbations and of the corresponding extrinsic perturbation velocity, $v$
say. For each mode number the criterion for instability is the existence of
nonreal roots for a certain cubic eigenvalue equation for the corresponding
mode frequency. A very simple sufficient but not necessary condition for
reality of the roots and therefore absence of instability is that the
characteristic velocity ratio, $c/v$ be greater than or equal to unity. Closer
examination of the low velocity (experimentally accessible) nonrelativistic
regime shows that in that limit the criterion for instability is just that the
dimensionless characteristic ratio $c/v$ be less than a critical value $\chi_c$
whose numerical value is approximately $1\over 2$. In the relativistic regime
that is relevant to superconducting cosmic strings the situation is rather
delicate, calling for more detailed investigation that is postponed for future
work.Comment: 20 page TeX file (with typo corrections and added reference) of
  manuscript published (with shorter title) in Annals of Physic
Nonabelian Berry Phases in Baryons

We show how generic nonabelian gauge fields can be induced in baryons when a
hierarchy of fast degrees of freedom is integrated out. We identify them with
nonabelian Berry potentials and discuss their role in transmuting quantum
numbers in bag and soliton models of baryons. The resulting baryonic spectra
for both light and heavy quark systems are generic and resemble closely the
excitation spectrum of diatomic molecules. The symmetry restoration in the
system, i.e., the electronic rotational invariance in diatomic molecules, the
heavy-quark symmetry in heavy baryons etc. is interpreted in terms of the
vanishing of nonabelian Berry potentials that otherwise govern the hyperfine
splitting.Comment: Latex 35 pages (2 figures not added, will be faxed if requested),
  NTG-92-2
Four-Fermion Theory and the Conformal Bootstrap

We employ the conformal bootstrap to re-examine the problem of finding the
critical behavior of four-Fermion theory at its strong coupling fixed point.
Existence of a solution of the bootstrap equations indicates self-consistency
of the assumption that, in space-time dimensions less than four, the
renormalization group flow of the coupling constant of a four-Fermion
interaction has a nontrivial fixed point which is generally out of the
perturbative regime. We exploit the hypothesis of conformal invariance at this
fixed point to reduce the set of the Schwinger-Dyson bootstrap equations for
four-Fermion theory to three equations which determine the scale dimension of
the Fermion field $\psi$, the scale dimension of the composite field
$\bar{\psi}\psi$ and the critical value of the Yukawa coupling constant. We
solve the equations assuming this critical value to be small. We show that this
solution recovers the fixed point for the four-fermion interaction with
$N$-component fermions in the limit of large $N$ at (Euclidean) dimensions $d$
between two and four. We perform a detailed analysis of the $1/N$-expansion in
$d=3$ and demonstrate full agreement with the conformal bootstrap. We argue
that this is a useful starting point for more sophisticated computations of the
critical indices.Comment: 31pp, text and figures both in Latex, UBCTP 92-3
Developing the Covariant Batalin-Vilkovisky approach to String Theory

We investigate the variation of the string field action under changes of the
string field vertices giving rise to different decompositions of the moduli
spaces of Riemann surfaces. We establish that any such change in the string
action arises from a field transformation canonical with respect to the
Batalin-Vilkovisky (BV) antibracket, and find the explicit form of the
generator of the infinitesimal transformations. Two theories using different
decompositions of moduli space are shown to yield the same gauge fixed action
upon use of different gauge fixing conditions. We also elaborate on recent work
on the covariant BV formalism, and emphasize the necessity of a measure in the
space of two dimensional field theories in order to extend a recent analysis of
background independence to quantum string field theory.Comment: 39 pp. MIT-CTP-2184. --Extra references added-
The Electromagnetic Interactions of Electrons in the Lowest Landau Level

Starting from a system of planar electrons in a strong magnetic field normal
to the plane, interacting with perturbing electromagnetic fields, an effective
Lagrangian for the fermions in the lowest Landau level (L.L.L.) has been
derived. By choosing a suitable background electrostatic potential, an
incompressible droplet of these electrons is constructed. The gauge invariant
effective Lagrangian for the electrons in the L.L.L. is shown to split
naturally into a $1+1$ dimensional Lagrangian for the electrons on the surface
of the droplet and into a $2+1$ dimensional gauge-field Lagrangian representing
the contribution of the interior of the droplet. Upon bosonization, the former
represents the surface vibrations of the droplet. Individually neither of these
two actions is gauge invariant, but it is shown that the gauge dependence from
the two pieces cancels out. This demonstrates that the edge degrees of freedom
are essential for maintaining gauge invariance.Comment: 17 pages, Plain tex, CCNY-HEP-93/
Harmonic space and quaternionic manifolds

We find a principle of harmonic analyticity underlying the quaternionic
(quaternion-K\"ahler) geometry and solve the differential constraints which
define this geometry. To this end the original $4n$-dimensional quaternionic
manifold is extended to a bi-harmonic space. The latter includes additional
harmonic coordinates associated with both the tangent local $Sp(1)$ group and
an extra rigid $SU(2)$ group rotating the complex structures. Then the
constraints can be rewritten as integrability conditions for the existence of
an analytic subspace in the bi-harmonic space and solved in terms of two
unconstrained potentials on the analytic subspace. Geometrically, the
potentials have the meaning of vielbeins associated with the harmonic
coordinates. We also establish a one-to-one correspondence between the
quaternionic spaces and off-shell $N=2$ supersymmetric sigma-models coupled to
$N=2$ supergravity. The general $N=2$ sigma-model Lagrangian when written in
the harmonic superspace is composed of the quaternionic potentials. Coordinates
of the analytic subspace are identified with superfields describing $N=2$
matter hypermultiplets and a compensating hypermultiplet of $N=2$ supergravity.
As an illustration we present the potentials for the symmetric quaternionic
spaces.Comment: 44 pages, LATEX, JHU-TIPAC-920023, ENSLAPP-L-405-92, MPI-Ph/92-8
Reaction-Diffusion Processes, Critical Dynamics and Quantum Chains

The master equation describing non-equilibrium one-dimensional problems like
diffusion limited reactions or critical dynamics of classical spin systems can
be written as a Schr\"odinger equation in which the wave function is the
probability distribution and the Hamiltonian is that of a quantum chain with
nearest neighbor interactions. Since many one-dimensional quantum chains are
integrable, this opens a new field of applications. At the same time physical
intuition and probabilistic methods bring new insight into the understanding of
the properties of quantum chains. A simple example is the asymmetric diffusion
of several species of particles which leads naturally to Hecke algebras and
$q$-deformed quantum groups. Many other examples are given. Several relevant
technical aspects like critical exponents, correlation functions and
finite-size scaling are also discussed in detail.Comment: Latex 52 pages (2 figures appended at the end), UGVA-DPT 1992/12-79
Systematic Differential Renormalization to All Orders

We present a systematic implementation of differential renormalization to all
orders in perturbation theory. The method is applied to individual Feynamn
graphs written in coordinate space. After isolating every singularity. which
appears in a bare diagram, we define a subtraction procedure which consists in
replacing the core of the singularity by its renormalized form givenby a
differential formula. The organizationof subtractions in subgraphs relies in
Bogoliubov's formula, fulfilling the requirements of locality, unitarity and
Lorentz invariance. Our method bypasses the use of an intermediate
regularization andautomatically delivers renormalized amplitudes which obey
renormalization group equations.Comment: TEX, 20 pages, UB-ECM-PF 93/4, 1 figureavailable upon reques