A numerical approach for liquefaction potential definition

Liquefaction phenomenon in saturated granular soil is not that frequent as amplification cases but can cause heavy damages on buildings and infrastructures whenever is occurs especially within superficial strata. In fact the lack of shear resistance of soil due to liquefaction affects mostly shallow foundations and road surfaces. Up now, several studies have been addressed to overpass the inadequacy of liquefaction safety factor by means of introducing the liquefaction potential. Nevertheless, the difficulty in (1) defining a scale of damage related to liquefaction potential values and (2) collecting field data from damages caused prevalently by liquefaction makes the punctual factor of safety still popular in engineering practice. In this paper a new approach to liquefaction potential estimation is proposed based on finite element dynamic analyses and on the concept of “significant volume” according to possible effects suffered by shallow foundations. One-dimensional simulation of liquefaction occurrence is performed by means of the Pastor-Zienkiewicz constitutive law. Hence the estimation of liquefaction potential is gained as well as the stress influence factor from Westergaard solution is calculated

Two-fluid dynamics for a Bose-Einstein condensate out of local equilibrium with the non-condensate

We extend our recent work on the two-fluid hydrodynamics of a Bose-condensed gas by including collisions involving both condensate and non-condensate atoms. These collisions are essential for establishing a state of local thermodynamic equilibrium between the condensate and non-condensate. Our theory is more general than the usual Landau two-fluid theory, to which it reduces in the appropriate limit, in that it allows one to describe situations in which a state of complete local equilibrium between the two components has not been reached. The exchange of atoms between the condensate and non-condensate is associated with a new relaxational mode of the gas.Comment: 4 pages, revtex, 1 postscript figure, Fig.1 has been correcte

Microstructural and magnetic characterization of Fe- and Ir-based multilayers

Nominal [Fe(t)/Ir(t'')](n) (M/Mtype), [FeOx(t)/IrOx(t'')](n) (O/O), and [Fe(t)/IrOx(t'')](n) (M/O) multilayers have been prepared by magnetron sputtering at room temperature. Composition, structure, and magnetic behavior have been analyzed. In the M/M samples, the Fe and Ir phases are identified as bcc and fcc, respectively. The magnetism evolves from bulklike iron to granular behavior as the thickness of the Fe layers decreases. An induced magnetic moment, ferromagnetically coupled to Fe, is observed on Ir by x-ray magnetic circular dichroism (XMCD). Besides, the presence of negative remanent magnetization is observed in the M/M samples. As for the M/O samples, the stronger affinity of iron for oxygen displaces the oxygen atoms giving rise to actual heterostructures that strongly differ from the nominal ones. For similar thickness of the two layers the Fe layer become oxidized while a mixture of metal and oxide phases is found in the Ir layer. The increase of the Fe thickness leads to a metallic Ir layer and a highly coercive (similar to 4.4 kOe) core-shell metal-oxide structure in the Fe layers

From Regular to Chaotic States in Atomic Nuclei

An interesting aspect of nuclear dynamics is the co--existence, in atomic nuclei, of regular and chaotic states. In the first part of the present work, we review the state of the art of nuclear dynamics and use a schematic shell model to show how a very simple and schematic nucleon--nucleon interaction can produce an order$\to$chaos transition. The second part is devoted to a discussion of the wave function behaviour and decay of chaotic states using some simple models (to be published in Rivista Nuovo Cimento).Comment: 65 pages, LaTex (the figures are not included), Preprint DFPD/94/TH/26, University of Padov

A Simple Entropic-Driving Separation Procedure of Low-Size Silver Clusters, Through Interaction with DNA

Synthesis and purification of metal clusters without strong binding agents by wet chemical methods are very attractive for their potential applications in many research areas. However, especially challenging is the separation of uncharged clusters with only a few number of atoms, which renders the usual techniques very difficult to apply. Herein, we report the first efficient separation of Ag2 and Ag3 clusters using the different entropic driving forces when such clusters interact with DNA, into which Ag3 selectively intercalates. After sequential dialysis of the samples and denaturalizing the DNA-Ag3 complex, pure Ag2 can be found in the dialysate after extensive dialysis. Free Ag3 is recovered after DNA denaturation

Recurring adaptive introgression of a supergene variant that determines social organization

Introgression has been proposed as an essential source of adaptive genetic variation. However, a key barrier to adaptive introgression is that recombination can break down combinations of alleles that underpin many traits. This barrier might be overcome in supergene regions, where suppressed recombination leads to joint inheritance across many loci. Here, we study the evolution of a large supergene region that determines a major social and ecological trait in Solenopsis fire ants: whether colonies have one queen or multiple queens. Using coalescent-based phylogenies built from the genomes of 365 haploid fire ant males, we show that the supergene variant responsible for multiple-queen colonies evolved in one species and repeatedly spread to other species through introgressive hybridization. This finding highlights how supergene architecture can enable a complex adaptive phenotype to recurrently permeate species boundaries

Reference interval for immature platelet fraction on Sysmex XN haematology analyser in adult population

Introduction: The Sysmex XN-series haematology analyser has newly adopted a fluorescent channel to measure immature platelet fraction (IPF). To promote the clinical utility of this promising parameter, establishing a reliable reference interval is mandatory. According to previous studies, IPF values may be affected by the employed analyser and the ethnic background of the individual, but no differences seem to be found between individuals’ genders. Therefore, this study aimed to define the reference interval for IPF in a Spanish population following Clinical and Laboratory Standard Institute (CLSI) guidelines. Materials and methods: A total of 153 healthy Caucasian adults from Spain met the inclusion criteria. IPF measurement was performed by means of a Sysmex XN-2000 haematology analyser. A non-parametric percentile method was used to calculate the reference intervals in accordance with CLSI guidelines. Results: The obtained reference interval for IPF on the Sysmex XN-2000 was 1.6–9.6% (90% confidence intervals (CIs) were 1.5–1.8 and 9.3–11.5, respectively). No significant gender difference in IPF reference intervals was observed (P = 0.101). Conclusions: This study provides, for the first time, a reference interval for IPF using a Sysmex XN-2000 in a Spanish population, ranging from 1.6 to 9.6%. These data are needed to evaluate platelet production in several conditions such as thrombocytopenia, inflammatory states and cardiovascular diseases, as well as for future research

Kinetic Properties of a Bose-Einstein Gas at Finite Temperature

We study, in the framework of the Boltzmann-Nordheim equation (BNE), the kinetic properties of a boson gas above the Bose-Einstein transition temperature $T_c$. The BNE is solved numerically within a new algorithm, that has been tested with exact analytical results for the collision rate of an homogeneous system in thermal equilibrium. In the classical regime ($T > 6~ T_c$), the relaxation time of a quadrupolar deformation in momentum space is proportional to the mean free collision time $\tau_{relax} \sim T^{-1/2}$. Approaching the critical temperature ($T_c < T < 2.7~ T_c$), quantum statistic effects in BNE become dominant, and the collision rate increases dramatically. Nevertheless, this does not affect the relaxation properties of the gas that depend only on the spontaneous collision term in BNE. The relaxation time $\tau_{relax}$ is proportional to $(T - T_c)^{-1/2}$, exhibiting a critical slowing down. These phenomena can be experimentally confirmed looking at the damping properties of collective motions induced on trapped atoms. The possibility to observe a transition from collisionless (zero-sound) to hydrodynamic (first-sound) is finally discussed.Comment: RevTeX, 5 figures. Submitted to Phys. Rev.