170,572 research outputs found
Asymptotic expansion for the wave function in a one-dimensional model of inelastic interaction
No full textWe consider a two-body quantum system in dimension one composed by a test particle interacting with a harmonic oscillator placed at the position a > 0. At time zero the test particle is concentrated around the position R(0) with average velocity+/-v(0) while the oscillator is in its ground state. In a suitable scaling limit, corresponding for the test particle to a semiclassical regime with small energy exchange with the oscillator, we give a complete asymptotic expansion of the wave function of the system in both cases R(0) a. (C) 2011 American Institute of Physics. [doi:10.1063/1.3549587
Environmental impact assessment: A multilevel, multi-parametric framework for coastal waters
No full textIn any process of Environmental Impact Assessment (EIA) a key role is played by the action of monitoring. Indeed, the acquisition of real field data provides the evidence of the environmental status and identifies hazards and sources of pollution. When environmental pollution is revealed, it is important to identify the source following the source-path-target model. However, when monitoring operations are planned, often the three-dimensional (3D) nature of monitored hotspots is neglected. Instead, information can be gathered through a multi-parametric, multi-level framework, which combines multiple disciplines and generates correlations between several data sets acquired in the analysed scenario. This novel new framework is named MuM3, meaning that the proposed Monitoring (M) is MultiDisciplinary, Multi-level and Multi-parametric (i.e. Mu) and it is developed in all the three dimensions of physical space (the superscript ‘3’). This paper outlines the implementation of this framework. In particular, monitoring polluted coastal waters refers to one of the critical areas identified by EIA regulations. The framework incorporates different spatial scales of observation (Levels) and the potential sensors that can be used at each Level. A three-step work-flow model describes the raw data acquisition and the transformation and integration of different indicators into useful information for EIA. A schematic flow chart describes the approach to developing multi-level, multi-parameter connections. Extension of this framework can be applied to any EIA, especially in the case of critical areas that are identified by the regulations as: (i) Wetlands, riparian areas, river mouths; (ii) Mountain and forest areas; (iii) Nature reserves and parks; (iv) Densely populated areas; (v) Landscapes and sites of historical, cultural or archaeological significance
Semiclassical wave-packets emerging from interaction with an environment
No full textWe study the quantum evolution in dimension three of a system composed by a test particle interacting with an environment made of N harmonic oscillators. At time zero the test particle is described by a spherical wave, i.e., a highly correlated continuous superposition of states with well localized position and momentum, and the oscillators are in the ground state. Furthermore, we assume that the positions of the oscillators are not collinear with the center of the spherical wave. Under suitable assumptions on the physical parameters characterizing the model, we give an asymptotic expression of the solution of the Schrodinger equation of the system with an explicit control of the error. The result shows that the approximate expression of the wave function is the sum of two terms, orthogonal in L-2(R3(N+1)) and describing rather different situations. In the first one, all the oscillators remain in their ground state and the test particle is described by the free evolution of a slightly deformed spherical wave. The second one consists of a sum of N terms where in each term there is only one excited oscillator and the test particle is correspondingly described by the free evolution of a wave packet, well concentrated in position and momentum. Moreover, the wave packet emerges from the excited oscillator with an average momentum parallel to the line joining the oscillator with the center of the initial spherical wave. Such wave packet represents a semiclassical state for the test particle, propagating along the corresponding classical trajectory. The main result of our analysis is to show how such a semiclassical state can be produced, starting from the original spherical wave, as a result of the interaction with the environment. (C) 2014 AIP Publishing LLC.We study the quantum evolution in dimension three of a system composed by a test
particle interacting with an environment made of N harmonic oscillators. At time zero
the test particle is described by a spherical wave, i.e., a highly correlated continuous
superposition of stateswith well localized position and momentum, and the oscillators
are in the ground state. Furthermore, we assume that the positions of the oscillators
are not collinear with the center of the spherical wave. Under suitable assumptions on
the physical parameters characterizing the model, we give an asymptotic expression
of the solution of the Schr ̈odinger equation of the system with an explicit control
of the error. The result shows that the approximate expression of the wave function
is the sum of two terms, orthogonal in L2(R3(N+1)) and describing rather different
situations. In the first one, all the oscillators remain in their ground state and the test
particle is described by the free evolution of a slightly
The NLS Equation in Dimension One with Spatially Concentrated Nonlinearities: the Pointlike Limit
No full textIn the present paper, we study the following scaled nonlinear Schrödinger equation (NLS) in one space dimension:(Formula Presented.)(Formula Presented.) This equation represents a nonlinear Schrödinger equation with a spatially concentrated nonlinearity. We show that in the limit (Formula Presented.) the weak (integral) dynamics converges in (Formula Presented.) to the weak dynamics of the NLS with point-concentrated nonlinearity: (Formula Presented.) where Hα is the Laplacian with the nonlinear boundary condition at the origin (Formula Presented.) and (Formula Presented.). The convergence occurs for every (Formula Presented.) if V ≥ 0 and for every (Formula Presented.) otherwise. The same result holds true for a nonlinearity with an arbitrary number N of concentration points
Characterization of tetA-like gene encoding for a major facilitator superfamily efflux pump in Streptococcus thermophilus
No full textEfflux pumps are membrane proteins involved in the active extrusion of a wide range of structurally dissimilar substrates from cells. A multidrug efflux pump named TetA belonging to the major facilitator superfamily (MFS) of transporters was identified in the Streptococcus thermophilus DSM 20617(T) genome. The tetA-like gene was found in the genomes of a number of S. thermophilus strains sequenced to date and in Streptococcus macedonicus ACA-DC 198, suggesting a possible horizontal gene transfer event between these two Streptococcus species, which are both adapted to the milk environment. Flow cytometry (single-cell) analysis revealed bistable TetA activity in the S. thermophilus population, and tetA-like gene over-expression resulted in a reduced susceptibility to ethidium bromide, tetracycline, and other toxic compounds even when the efflux pump was over-expressed in a strain naturally lacking tetA-like gene
Well-posedness of the three-dimensional NLS equation with sphere-concentrated nonlinearity
No full textWe discuss strong local and global well-posedness for the three-dimensional
NLS equation with nonlinearity concentrated on . Precisely, local
well-posedness is proved for any power-nonlinearity, while global
well-posedness is obtained either for small data or in the defocusing case
under some growth assumptions. With respect to point-concentrated NLS models,
widely studied in the literature, here the dimension of the support of the
nonlinearity does not allow a direct extension of the known techniques and
calls for new ideas.Comment: 40 pages. Keywords: NLS equation, concentrated nonlinearity, unit
sphere, well-posedness, spherical harmonics. Minor changes have been made
with respect to the previous versio
TETA-treated Caco-2 quantitative label-free LC-MS/MS
No full textRaw and filtered quantitative proteomic profile data sets for 25 μM TETA-treated Caco-2, growth media repleted Caco-2 relative to unexposed control Caco-2 cell
A new inositol-hopanoid from an Indonesia specimen of the sponge Plakortis simplex
No full textThe Caribbean sponge Plakortis simplex has been extensively studied by our group, and a large variety of unusual glycolipids and other amphiphilic compounds have been isolated, including simplexide, discoside, and 12-methylbacteriohopanetetrol .Recently, we had occasion to analyze for glycolipids an Indonesian specimen of P. simplex. In spite of the geographical distance, we found that the glycolipids composition of the Indonesian and Caribbean specimens were very similar. However, the Indonesian P. simplex also contained a new glycolipid, combining structural features of hopanoids and discoside, whose structure elucidation will be described
Three-Body Hamiltonian with Regularized Zero-Range Interactions in Dimension Three
No full textWe study the Hamiltonian for a system of three identical bosons in dimension three interacting via zero-range forces. In order to avoid the fall to the center phenomenon emerging in the standard Ter-Martirosyan-Skornyakov (TMS) Hamiltonian, known as Thomas effect, we develop in detail a suggestion given in a seminal paper of Minlos and Faddeev in 1962 and we construct a regularized version of the TMS Hamiltonian which is self-adjoint and bounded from below. The regularization is given by an effective three-body force, acting only at short distance, that reduces to zero the strength of the interactions when the positions of the three particles coincide. The analysis is based on the construction of a suitable quadratic form which is shown to be closed and bounded from below. Then, domain and action of the corresponding Hamiltonian are completely characterized and a regularity result for the elements of the domain is given. Furthermore, we show that the Hamiltonian is the norm resolvent limit of Hamiltonians with rescaled non-local interactions, also called separable potentials, with a suitably renormalized coupling constant
<sup>64</sup>Cu-TETA-CD45 radiolabeling of hPBSC.
No full text<p>hPBSC were radiolabeled with 0, 20, 40, 80, or 160 µCi/mL of <sup>64</sup>Cu-TETA-CD45. No significant changes in cell viability or degree of labeling were observed with increasing concentrations. A decline in cell growth and colony formation was observed when cells were incubated with <sup>64</sup>Cu-TETA-CD45 at a concentration >20 µCi/mL.</p
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