Taxonomy and biostratigraphy of new and emended species of Cenozoic deep-water agglutinated foraminifera from the Labrador and North Seas

Deep marine, fine grained sedimentary strata of Maastrichtian through Miocene age in the Labrador and North Sea sedimentary basins are rich in agglutinated benthic foraminifera. Six new taxa have been found in these regions, several of which also extend to other circum-Atlantic Paleogene localities. The new taxa are: Ammomarginulina aubertae, n. sp. (Maastrichtian to Eocene), Adercotryma agterbergi, n. sp. (middle Eocene to lower Oligocene), Reticulophragmoides jarvisi (Thalmann) emended herein (Paleocene to lower Oligocene), Reticulophragmoides sp. 5 (Oligocene to Miocene), and Spiroplectammina navarroana Cushman emended herein (Maastrichtian to lower middle Eocene). The last occurrences of these taxa are important elements in the high-resolution probabilistic biozonations for the Labrador and North Sea basins

Theory of 4e versus 2e supercurrent in frustrated Josepshon-junction rhombi chain

We consider a chain of Josepshon-junction rhombi (proposed originally in \cite{Doucot}) in quantum regime, and in the realistic case when charging effects are determined by junction capacitances. In the maximally frustrated case when magnetic flux through each rhombi $\Phi_r$ is equal to one half of superconductive flux quantum $\Phi_0$, Josepshon current is due to correlated transport of {\em pairs of Cooper pairs}, i.e. charge is quantized in units of $4e$. Sufficiently strong deviation $\delta\Phi \equiv |\Phi_r-\Phi_0/2| > \delta\Phi^c$ from the maximally frustrated point brings the system back to usual $2e$-quantized supercurrent. We present detailed analysis of Josepshon current in the fluctuation-dominated regime (sufficiently long chains) as function of the chain length, $E_J/E_C$ ratio and flux deviation $\delta\Phi$. We provide estimates for the set of parameters optimized for the observation of $4e$-supercurrent.Comment: 23 pages, 9 figure

Epiphytic bryophytes of Monteverde, Costa Rica

A survey of the literature and collections in the Monteverde Cloud Forest Preserve and adjacent pastureland yielded a total of 198 epiphytic bryophyte taxa (120 species of hepatics in 50 genera, 77 species of moss in 48 genera, and 1 hornwort): 178 in the primary forest, 63 in the secondary forest, and 84 in the pastureland

Mass mortality and extraterrestrial impacts

The discovery of iridium enrichment at the Cretaceous/Tertiary boundary resulted in formulation of hypothesis of a cometary or asteroid impact as the cause of the biological extinctions at this boundary. Subsequent discoveries of geochemical anomalies at major stratigraphic boundaries like the Precambrian/Cambrian, Permian/Triassic, Middle/Late Jurassic, resulted in the application of similar extraterrestrial impact theories to explain biological changes at these boundaries. Until recently the major physical evidence, as is the location of the impact crater site, to test the impact induced biological extinction was lacking. The diameter of such a crater would be in the range of 60 to 100 km. The recent discovery of the first impact crater in the ocean provide the first opportunity to test the above theory. The crater, named Montagnais and located on the outer shelf off Nova Scotia, Canada, has a minimum diameter of 42 km, with some evidence to a diameter of more than 60 km. At the Montagnais impact site, micropaleontological analysis of the uppermost 80 m of the fall-back breccia represented by a mixture of pre-impact sediments and basement rocks which fills the crater and of the basal 50 m of post-impact marine sediments which overly the impact deposits, revealed presence of diversified foraminiferal and nannoplankton assemblages. The sediments which are intercalated within the uppermost part of the fall-back breccia, had to be deposited before the meteorite impact. The post-impact deposits were laid down almost immediately after the impact as also supported by the micropaleontological data. In conclusion, micropaleontological studies of sediments from the first submarine impact crater site identified in the ocean did not reveal any mass extinction or significant biological changes at the impact site or in the proximal deep ocean basin

Vortex Plasma in a Superconducting Film with Magnetic Dots

We consider a superconducting film, placed upon a magnetic dot array. Magnetic moments of the dots are normal to the film and randomly oriented. We determine how the concentration of the vortices in the film depends on the magnetic moment of a dot at low temperatures. The concentration of the vortices, bound to the dots, is proportional to the density of the dots and depends on the magnetization of a dot in a step-like way. The concentration of the unbound vortices oscillates about a value, proportional to the magnetic moment of the dots. The period of the oscillations is equal to the width of a step in the concentration of the bound vortices.Comment: RevTeX, 4 page

The spatial statistical properties of wave functions in a disordered finite one-dimensional sample

For a given wave function one can define a quantity $\mu_E$ having a meaning of its inverse spatial size. The Laplace transform of the distribution function $P(\mu_E)$ is calculated analytically for a 1D disordered sample with a finite length $L$.Comment: LaTEX, 7 pages, Preprint IFUM-456/FT, Milano, Jan.199

Decoherence of number states in phase-sensitive reservoirs

The non-unitary evolution of initial number states in general Gaussian environments is solved analytically. Decoherence in the channels is quantified by determining explicitly the purity of the state at any time. The influence of the squeezing of the bath on decoherence is discussed. The behavior of coherent superpositions of number states is addressed as well.Comment: 5 pages, 2 figures, minor changes, references adde

Local density approximation for a perturbative equation of state

The knowledge of a series expansion of the equation of state provides a deep insight into the physical nature of a quantum system. Starting from a generic ``perturbative'' equation of state of a homogeneous ultracold gas we make predictions for the properties of the gas in the presence of harmonic confinement. The local density approximation is used to obtain the chemical potential, total and release energies, Thomas-Fermi size and density profile of a trapped system in three-, two-, and one- dimensional geometries. The frequencies of the lowest breathing modes are calculated using scaling and sum-rule approaches and could be used in an experiment as a high precision tool for obtaining the expansion terms of the equation of state. The derived formalism is applied to dilute Bose and Fermi gases in different dimensions and to integrable one-dimensional models. Physical meaning of expansion terms in a number of systems is discussed.Comment: 3 Figure

Dynamic response of 1D bosons in a trap

We calculate the dynamic structure factor S(q,omega) of a one-dimensional (1D) interacting Bose gas confined in a harmonic trap. The effective interaction depends on the strength of the confinement enforcing the 1D motion of atoms; interaction may be further enhanced by superimposing an optical lattice on the trap potential. In the compressible state, we find that the smooth variation of the gas density around the trap center leads to softening of the singular behavior of S(q,omega) at Lieb-1 mode compared to the behavior predicted for homogeneous 1D systems. Nevertheless, the density-averaged response remains a non-analytic function of q and omega at Lieb-1 mode in the limit of weak trap confinement. The exponent of the power-law non-analyticity is modified due to the inhomogeneity in a universal way, and thus, bears unambiguously the information about the (homogeneous) Lieb-Liniger model. A strong optical lattice causes formation of Mott phases. Deep in the Mott regime, we predict a semi-circular peak in S(q,\omega) centered at the on-site repulsion energy, omega=U. Similar peaks of smaller amplitudes exist at multiples of U as well. We explain the suppression of the dynamic response with entering into the Mott regime, observed recently by D. Clement et al., Phys. Rev. Lett. v. 102, p. 155301 (2009), based on an f-sum rule for the Bose-Hubbard model.Comment: 24 pages, 11 figure