Yes, they can! Three-banded armadillos Tolypeutes sp. (Cingulata: Dasypodidae) dig their own burrows.

It is believed that the two species of Tolypeutes Illiger, 1811are the only armadillos that do not dig their own burrows, and that these species simply re-use burrows dug by other species. Here, we show that Tolypeutes matacus (Desmarest, 1804) and Tolypeutes tricinctus (Linnaeus, 1758) dig their own burrows. We describe the burrows and three other types of shelters used by them, and provide measurements and frequency of use of the different types of shelter. We have studied free-ranging individuals of T. matacus in two locations in Central Brazil and individuals of T. tricinctus in semi-captivity in the Northeast of Brazil. Individuals of T. matacus were found primarily in small burrows (76%), straw nests (13%), shallow depressions covered with leaf-litter (7%) or in straw nests made on shallow depressions (4%). Adult males and females of T. matacus did not differ in frequency of use of different types of shelter. Sub-adults T. matacus used shallow depressions and nests more often (40%) than adults (22%) and nurslings (10%). Nurslings of T. matacus reused the shelters more frequently (66%), than sub-adults (46%) and adults (35%). Adult females reused burrows and other types of shelter more frequently than adult males. Tolypeutes tricinctus rested mainly in burrows and under leaf-litter, but did not dig depressions or build nests. Tolypeutes tricinctus occasionally used burrows dug by Euphractus sexcinctus (Linnaeus, 1758), but T. matacus never used burrows dug by other species. Nursling T. matacus always shared shelter with an adult female therefore, both used shelters with similar frequency. Adult females and nurslings of T. matacus reused shelters in higher frequency. That can be explained by the fact that adult females with offspring tend to remain for consecutive nights in the same burrow when cubs are recently born. Due to their smaller body size, subadult T. matacus used shelter strategies that require less energetic effort more frequently than adults and nurslings. The habit of covering the burrow entrance with foliage and the burrow?s reduced depth, indicates that Tolypeutes use of burrows is more likely to be related to parental care behavior and thermoregulation strategies than to defense mechanisms. We are confident that the burrows used for resting were indeed dug by Tolypeutes because, besides the direct observation of armadillos digging burrows, the measures of the burrows are very distinctive from those presented as characteristic for the co-occurring burrowing species and are congruent with Tolypeutes size and carapace shape. The newly acquired knowledge that species of Tolypeutes dig burrows can be used to increase the well-being of individuals kept in captivity by adapting enclosures to enable their digging behavior. In addition, this information contributes not only to the study of the ecology and natural history of the species, but can shed new light on the study of the anatomy of specialized diggers. Tolypeutes spp. can comprise the least fossorial of all living armadillo species, but they can no longer be classified as non-diggers

Semiclassical Analysis of Extended Dynamical Mean Field Equations

The extended Dynamical Mean Field Equations (EDMFT) are analyzed using semiclassical methods for a model describing an interacting fermi-bose system. We compare the semiclassical approach with the exact QMC (Quantum Montecarlo) method. We found the transition to an ordered state to be of the first order for any dimension below four.Comment: RevTex, 39 pages, 16 figures; Appendix C added, typos correcte

Universal Parametric Correlations of Conductance Peaks in Quantum Dots

We compute the parametric correlation function of the conductance peaks in chaotic and weakly disordered quantum dots in the Coulomb blockade regime and demonstrate its universality upon an appropriate scaling of the parameter. For a symmetric dot we show that this correlation function is affected by breaking time-reversal symmetry but is independent of the details of the channels in the external leads. We derive a new scaling which depends on the eigenfunctions alone and can be extracted directly from the conductance peak heights. Our results are in excellent agreement with model simulations of a disordered quantum dot.Comment: 12 pages, RevTex, 2 Postscript figure

Finite temperature effects in Coulomb blockade quantum dots and signatures of spectral scrambling

The conductance in Coulomb blockade quantum dots exhibits sharp peaks whose spacings fluctuate with the number of electrons. We derive the temperature-dependence of these fluctuations in the statistical regime and compare with recent experimental results. The scrambling due to Coulomb interactions of the single-particle spectrum with the addition of an electron to the dot is shown to affect the temperature-dependence of the peak spacing fluctuations. Spectral scrambling also leads to saturation in the temperature dependence of the peak-to-peak correlator, in agreement with recent experimental results. The signatures of scrambling are derived using discrete Gaussian processes, which generalize the Gaussian ensembles of random matrices to systems that depend on a discrete parameter -- in this case, the number of electrons in the dot.Comment: 14 pages, 4 eps figures included, RevTe

‘I think I'm more free with them'—Conflict, Negotiation and Change in Intergenerational Relations in African Families Living in Britain

While the family is increasingly being recognised as pivotal to migration, there remain too few studies examining how migration impacts on intergenerational relationships. Although traditional intergenerational gaps are intensified by migration, arguably there has been an over-emphasis on the divisions between ‘traditional’ parents and ‘modern’ children at the expense of examining the ways in which both generations adapt. As Foner and Dreby [2011. “Relations Between the Generations in Immigrant Families.” Annual Review of Sociology 37: 545–564] stress, the reality of post-migration intergenerational relations is inevitably more complex, requiring the examination of both conflict and cooperation. This article contributes to this growing literature by discussing British data from comparative projects on intergenerational relations in African families (in Britain, France and South Africa). It argues that particular understandings can be gained from examining the adaptation of parents and parenting strategies post-migration and how the reconfiguration of family relations can contribute to settlement. By focusing on how both parent and child generations engage in conflict and negotiation to redefine their relationships and expectations, it offers insight into how families navigate and integrate the values of two cultures. In doing so, it argues that the reconfiguration of gender roles as a result of migration offers families the space to renegotiate their relationships and make choices about what they transmit to the next generation

Universal Correlations of Coulomb Blockade Conductance Peaks and the Rotation Scaling in Quantum Dots

We show that the parametric correlations of the conductance peak amplitudes of a chaotic or weakly disordered quantum dot in the Coulomb blockade regime become universal upon an appropriate scaling of the parameter. We compute the universal forms of this correlator for both cases of conserved and broken time reversal symmetry. For a symmetric dot the correlator is independent of the details in each lead such as the number of channels and their correlation. We derive a new scaling, which we call the rotation scaling, that can be computed directly from the dot's eigenfunction rotation rate or alternatively from the conductance peak heights, and therefore does not require knowledge of the spectrum of the dot. The relation of the rotation scaling to the level velocity scaling is discussed. The exact analytic form of the conductance peak correlator is derived at short distances. We also calculate the universal distributions of the average level width velocity for various values of the scaled parameter. The universality is illustrated in an Anderson model of a disordered dot.Comment: 35 pages, RevTex, 6 Postscript figure

Interactions and Interference in Quantum Dots: Kinks in Coulomb Blockade Peak Positions

We investigate the spin of the ground state of a geometrically confined many-electron system. For atoms, shell structure simplifies this problem-- the spin is prescribed by the well-known Hund's rule. In contrast, quantum dots provide a controllable setting for studying the interplay of quantum interference and electron-electron interactions in general cases. In a generic confining potential, the shell-structure argument suggests a singlet ground state for an even number of electrons. The interaction among the electrons produces, however, accidental occurrences of spin-triplet ground states, even for weak interaction, a limit which we analyze explicitly. Variaton of an external parameter causes sudden switching between these states and hence a kink in the conductance. Experimental study of these kinks would yield the exchange energy for the ``chaotic electron gas''.Comment: 4 pages, 2 ps figs included using epsf.sty. Revision: added important reference and consequent text changes, other small correction

Self-consistent quantal treatment of decay rates within the perturbed static path approximation

The framework of the Perturbed Static Path Approximation (PSPA) is used to calculate the partition function of a finite Fermi system from a Hamiltonian with a separable two body interaction. Therein, the collective degree of freedom is introduced in self-consistent fashion through a Hubbard-Stratonovich transformation. In this way all transport coefficients which dominate the decay of a meta-stable system are defined and calculated microscopically. Otherwise the same formalism is applied as in the Caldeira-Leggett model to deduce the decay rate from the free energy above the so called crossover temperature $T_0$.Comment: 17 pages, LaTex, no figures; final version, accepted for publication in PRE; e-mail: [email protected]

A Uniform Approximation for the Fidelity in Chaotic Systems

In quantum/wave systems with chaotic classical analogs, wavefunctions evolve in highly complex, yet deterministic ways. A slight perturbation of the system, though, will cause the evolution to diverge from its original behavior increasingly with time. This divergence can be measured by the fidelity, which is defined as the squared overlap of the two time evolved states. For chaotic systems, two main decay regimes of either Gaussian or exponential behavior have been identified depending on the strength of the perturbation. For perturbation strengths intermediate between the two regimes, the fidelity displays both forms of decay. By applying a complementary combination of random matrix and semiclassical theory, a uniform approximation can be derived that covers the full range of perturbation strengths. The time dependence is entirely fixed by the density of states and the so-called transition parameter, which can be related to the phase space volume of the system and the classical action diffusion constant, respectively. The accuracy of the approximations are illustrated with the standard map.Comment: 16 pages, 4 figures, accepted in J. Phys. A, special edition on Random Matrix Theor