Ground State Spin Structure of Strongly Interacting Disordered 1D Hubbard Model

We study the influence of on-site disorder on the magnetic properties of the ground state of the infinite U 1D Hubbard model. We find that the ground state is not ferromagnetic. This is analyzed in terms of the algebraic structure of the spin dependence of the Hamiltonian. A simple explanation is derived for the 1/N periodicity in the persistent current for this model.Comment: 3 pages, no figure

Breaking of N=8 magicity in 13Be

Structure of $^{13}$Be was investigated with antisymmetrized molecular dynamics. The variation after spin and parity projections was performed. An unnatural parity $1/2^-$ state was suggested to be lower than $5/2^+$ state indicating that vanishing of the N=8 magic number occurs in $^{13}$Be. A low-lying $3/2^+$ state with a $2\hbar\omega$ configuration was also suggested. Developed cluster structures were found in the intruder states. Lowering mechanism of the intruder states was discussed in terms of molecular orbitals around a $2\alpha$ core.Comment: 9 pages, 8 figures, submitted to PR

Solution of the Bohr hamiltonian for soft triaxial nuclei

The Bohr-Mottelson model is solved for a generic soft triaxial nucleus, separating the Bohr hamiltonian exactly and using a number of different model-potentials: a displaced harmonic oscillator in $\gamma$, which is solved with an approximated algebraic technique, and Coulomb/Kratzer, harmonic/Davidson and infinite square well potentials in $\beta$, which are solved exactly. In each case we derive analytic expressions for the eigenenergies which are then used to calculate energy spectra. Here we study the chain of osmium isotopes and we compare our results with experimental information and previous calculations.Comment: 13 pages, 9 figure

Glassy states in lattice models with many coexisting crystalline phases

We study the emergence of glassy states after a sudden cooling in lattice models with short range interactions and without any a priori quenched disorder. The glassy state emerges whenever the equilibrium model possesses a sufficient number of coexisting crystalline phases at low temperatures, provided the thermodynamic limit be taken before the infinite time limit. This result is obtained through simulations of the time relaxation of the standard Potts model and some exclusion models equipped with a local stochastic dynamics on a square lattice.Comment: 12 pages, 4 figure

Measurement Theory in Lax-Phillips Formalism

It is shown that the application of Lax-Phillips scattering theory to quantum mechanics provides a natural framework for the realization of the ideas of the Many-Hilbert-Space theory of Machida and Namiki to describe the development of decoherence in the process of measurement. We show that if the quantum mechanical evolution is pointwise in time, then decoherence occurs only if the Hamiltonian is time-dependent. If the evolution is not pointwise in time (as in Liouville space), then the decoherence may occur even for closed systems. These conclusions apply as well to the general problem of mixing of states.Comment: 14 pages, IASSNS-HEP 93/6

The Index Of Narrative Microstructure: A Clinical Tool For Analyzing School-Age Children's Narrative Performances

Purpose: This research was conducted to develop a clinical tool-the Index of Narrative Microstructure (INMIS)-that would parsimoniously account for important microstructural aspects of narrative production for school-age children. The study provides field test age- and grade-based INMIS values to aid clinicians in making normative judgments about microstructural aspects of pupils' narrative performance. Method: Narrative samples using a single-picture elicitation context were collected from 250 children age 5-12 years and then transcribed and segmented into T-units. A T-unit consists of a single main clause and any dependent constituents. The narrative transcripts were then coded and analyzed to document a comprehensive set of microstructural indices. Results: Factor analysis indicated that narrative microstructure consisted of 2 moderately related factors. The Productivity factor primarily comprised measures of word output, lexical diversity, and T-unit output. The Complexity factor comprised measures of syntactic organization, with mean length of T-units in words and proportion of complex T-units loading most strongly. Principal components analysis was used to provide a linear combination of 8 variables to approximate the 2 factors. Formulas for calculating a student's performance on the 2 factors using 8 narrative measures are provided. Conclusions: This study provided a method for professionals to calculate INMIS scores for narrative Productivity and Complexity for comparison against field test data for age (5- to 12-year-old) or grade (kindergarten to Grade 6) groupings. INMIS scores complement other tools in evaluating a child's narrative performance specifically and language abilities more generally.Communication Sciences and Disorder

Telerobotics: A simulation facility for university research

An experimental telerobotics (TR) simulation suitable for studying human operator (H.O.) performance is described. Simple manipulator pick-and-place and tracking tasks allowed quantitative comparison of a number of calligraphic display viewing conditions. A number of control modes could be compared in this TR simulation, including displacement, rate and acceleratory control using position and force joysticks. A homeomorphic controller turned out to be no better than joysticks; the adaptive properties of the H.O. can apparently permit quite good control over a variety of controller configurations and control modes. Training by optimal control example seemed helpful in preliminary experiments. An introduced communication delay was found to produce decrease in performance. In considerable part, this difficulty could be compensated for by preview control information. That neurological control of normal human movement contains a data period of 0.2 second may relate to this robustness of H.O. control to delay. The Ames-Berkeley enhanced perspective display was utilized in conjunction with an experimental helmet mounted display system (HMD) that provided stereoscopic enhanced views

Are Complementary Therapies and Integrative Care Cost-Effective? A Systematic Review of Economic Evaluations

Objective: A comprehensive systematic review of economic evaluations of complementary and integrative medicine (CIM) to establish the value of these therapies to health reform efforts. Data sources PubMed, CINAHL, AMED, PsychInfo, Web of Science and EMBASE were searched from inception through 2010. In addition, bibliographies of found articles and reviews were searched, and key researchers were contacted. Eligibility criteria for selecting studies Studies of CIM were identified using criteria based on those of the Cochrane complementary and alternative medicine group. All studies of CIM reporting economic outcomes were included. Study appraisal methods All recent (and likely most cost-relevant) full economic evaluations published 2001–2010 were subjected to several measures of quality. Detailed results of higher-quality studies are reported. Results: A total of 338 economic evaluations of CIM were identified, of which 204, covering a wide variety of CIM for different populations, were published 2001–2010. A total of 114 of these were full economic evaluations. And 90% of these articles covered studies of single CIM therapies and only one compared usual care to usual care plus access to multiple licensed CIM practitioners. Of the recent full evaluations, 31 (27%) met five study-quality criteria, and 22 of these also met the minimum criterion for study transferability (‘generalisability’). Of the 56 comparisons made in the higher-quality studies, 16 (29%) show a health improvement with cost savings for the CIM therapy versus usual care. Study quality of the cost-utility analyses (CUAs) of CIM was generally comparable to that seen in CUAs across all medicine according to several measures, and the quality of the cost-saving studies was slightly, but not significantly, lower than those showing cost increases (85% vs 88%, p=0.460). Conclusions: This comprehensive review identified many CIM economic evaluations missed by previous reviews and emerging evidence of cost-effectiveness and possible cost savings in at least a few clinical populations. Recommendations are made for future studies

Approximate resonance states in the semigroup decomposition of resonance evolution

The semigroup decomposition formalism makes use of the functional model for $C_{.0}$ class contractive semigroups for the description of the time evolution of resonances. For a given scattering problem the formalism allows for the association of a definite Hilbert space state with a scattering resonance. This state defines a decomposition of matrix elements of the evolution into a term evolving according to a semigroup law and a background term. We discuss the case of multiple resonances and give a bound on the size of the background term. As an example we treat a simple problem of scattering from a square barrier potential on the half-line.Comment: LaTex 22 pages 3 figure