794 research outputs found
The Relationship between Subclinical Asperger's Syndrome and Frontotemporal Lobar Degeneration
Background/Aims: The existence of the behavioral variant of frontotemporal dementia (bv-FTD), including senile Asperger’s syndrome (AS), has been proposed. However, there are no empirical case reports to support the proposal. In this report, we present 3 patients who showed symptoms of bv-FTD and demonstrated signs of autistic spectrum disorder, especially AS. Methods: We evaluated 3 subjects using the diagnostic criteria for bv-FTD, and their caregivers retrospectively provided data to calculate the Autism-Spectrum Quotient, Japanese version [Wakabayashi et al.: Shinrigaku Kenkyu 2004;75:78–84]. We also compared these data with those obtained from 3 individuals with Alzheimer’s disease. Results: All 3 patients met the criteria for bv-FTD and had a higher Autism-Spectrum Quotient score than did comparable Alzheimer’s disease subjects. Conclusion: It is possible that some senile persons with frontotemporal lobar degeneration-like maladaptive behavior may suffer from subclinical AS
Magnetic phase diagram of the spin-1/2 antiferromagnetic zigzag ladder
We study the one-dimensional spin-1/2 Heisenberg model with antiferromagnetic
nearest-neighbor J_1 and next-nearest-neighbor J_2 exchange couplings in
magnetic field h. With varying dimensionless parameters J_2/J_1 and h/J_1, the
ground state of the model exhibits several phases including three gapped phases
(dimer, 1/3-magnetization plateau, and fully polarized phases) and four types
of gapless Tomonaga-Luttinger liquid (TLL) phases which we dub TLL1, TLL2,
spin-density-wave (SDW_2), and vector chiral phases. From extensive numerical
calculations using the density-matrix renormalization-group method, we
investigate various (multiple-)spin correlation functions in detail, and
determine dominant and subleading correlations in each phase. For the
one-component TLLs, i.e., the TLL1, SDW_2, and vector chiral phases, we fit the
numerically obtained correlation functions to those calculated from effective
low-energy theories of TLLs, and find good agreement between them. The
low-energy theory for each critical TLL phase is thus identified, together with
TLL parameters which control the exponents of power-law decaying correlation
functions. For the TLL2 phase, we develop an effective low-energy theory of
two-component TLL consisting of two free bosons (central charge c=1+1), which
explains numerical results of entanglement entropy and Friedel oscillations of
local magnetization. Implications of our results to possible magnetic phase
transitions in real quasi-one-dimensional compounds are also discussed.Comment: 22 pages, 17 figures. v2: published versio
La formazione iniziale degli insegnanti. Visita di ricerca comparativa di esperti giapponesi all’Università di Torino
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