XXZ scalar products and KP

Using a Jacobi-Trudi-type identity, we show that the scalar product of a general state and a Bethe eigenstate in a finite-length XXZ spin-1/2 chain is (a restriction of) a KP tau function. This leads to a correspondence between the eigenstates and points on Sato's Grassmannian. Each of these points is a function of the rapidities of the corresponding eigenstate, the inhomogeneity variables of the spin chain and the crossing parameter.Comment: 14 pages, LaTeX2

Conditional expression in corticothalamic efferents reveals a developmental role for nicotinic acetylcholine receptors in modulation of passive avoidance behavior

Prenatal nicotine exposure has been linked to attention deficit hyperactivity disorder and cognitive impairment, but the sites of action for these effects of nicotine are still under investigation. High-affinity nicotinic acetylcholine receptors (nAChRs) contain the .2 subunit and modulate passive avoidance (PA) learning in mice. Using an inducible, tetracycline-regulated transgenic system, we generated lines of mice with expression of high-affinity nicotinic receptors restored in specific neuronal populations. One line of mice shows functional .2 subunit-containing nAChRs localized exclusively in corticothalamic efferents. Functional, presynaptic nAChRs are present in the thalamus of these mice as detected by nicotine-elicited rubidium efflux assays from synaptosomes. Knock-out mice lacking high-affinity nAChRs show elevated baseline PA learning, whereas normal baseline PA behavior is restored in mice with corticothalamic expression of these nAChRs. In contrast, nicotine can enhance PA learning in adult wild-type animals but not in corticothalamic-expressing transgenic mice. When these transgenic mice are treated with doxycycline in adulthood to switch off nAChR expression, baseline PA is maintained even after transgene expression is abolished. These data suggest that high-affinity nAChRs expressed on corticothalamic neurons during development are critical for baseline PA performance and provide a potential neuroanatomical substrate for changes induced by prenatal nicotine exposure leading to long-term behavioral and cognitive deficits

RUFINAMIDE (INOVELON) IN THE TREATMENT OF LENNOX–GASTAUT SYNDROME (A REVIEW OF LITERATURE AND CLINICAL CASE)

Lennox–Gastaut syndrome (LGS) is childhood-onset epileptic encephalopathy manifested by frequent polymorphic seizures, including tonic axial, obvious cognitive impairments, characteristic ECG changes, and therapeutic resistance. Due to the concurrence of several types of seizures in the clinical presentation of the disease and their resistance to drug therapy, great hopes are pinned on the design of novel antiepileptic drugs with fundamentally other mechanisms of action and aimed specially at treating this severe type of epilepsy. The authors review the foreign literature on the new antiepileptic drug rufinamide (Inovelon) registered in Russia in January 2015 to directly treat LGS as adjunctive treatment in children 4 years and older and adults. Multiple trials have demonstrated that rufinamide has efficacy and good tolerability in treating LGS.The authors describe an observed case of the efficacy of rufinamide in a 17-year-old male patient with LGS. Despite the drug resistance of epilepsy and no response to multiple antiepileptic drugs used alone and in different combinations, the incorporation of rufinamide into a treatment regimen had a pronounced therapeutic effect: the frequency of convulsive seizures decreased by 70 %. At the time of writing this paper, the patient has been receiving rufinamide for more 5 months. He has been tolerating the therapy well

High-field AFMR in single-crystalline La_{0.95}Sr_{0.05}MnO_3: Experimental evidence for the existence of a canted magnetic structure

High-field antiferromagnetic-resonance (AFMR) spectra were obtained in the frequency range 60 GHz < \nu < 700 GHz and for magnetic fields up to 8 T in twin-free single crystals of La_{0.95}Sr_{0.05}MnO_3. At low temperatures two antiferromagnetic modes were detected, which reveal different excitation conditions and magnetic field dependencies. No splitting of these modes was observed for any orientation of the static magnetic field excluding the phase-separation scenario for this composition. Instead, the full data set including the anisotropic magnetization can be well described using a two-sublattice model of a canted antiferromagnetic structure.Comment: 4 pages, 3 figure

Exchange couplings in the magnetic molecular cluster Mn12Ac

The magnetic properties of the molecular cluster Mn12Ac are due to the four Mn3+ ions which have spins S=3/2 and the eight Mn4+ ions with spins S=2. These spins are coupled by superexchange mechanism. We determine the four exchange couplings assuming a Heisenberg-type interaction between the ions. We use exact diagonalization of the spin Hamiltonian by a Lanczos algorithm and we adjust the couplings to reproduce the magnetization curve of Mn12Ac. We also impose the constraint of reproducing a gap of 35K between a S=10 ground state and a first excited state with S=9. We predict that there is an excited level with S=8 at 37K above the ground state, only slightly above the S=9 excited state which lies at 35K and the next excited state is a S=9 multiplet at 67K above the S=10 ground state.Comment: 15 pages, 6 figures, submitted to Phys Rev B, corrected a misTeX: values of J1, J2 have changed, refs update

EFFICACY AND TOLERABILITY OF LAMITOR (LAMOTRIGINE) IN THE TREATMENT OF IDIOPATHIC FOCAL AND GENERALIZED EPILEPSY IN MONOTHERAPY AND IN POLYTHERAPY IN CHILDREN AND ADOLESCENTS

Results of research of efficacy and tolerability of lamitor (lamotrigine) in the treatment of idiopathic focal and generalized forms of epilepsy as monotherapy or in polytherapy in children and adolescents are presented. 25 patients were included in our research, aged from 2 till 18 years, with idiopathic focal (n=10) and generalized (n=15) epilepsy, which received lamitor in monotherapy (5 patients) or in polytherapy (20 patients). As a whole, remission was reached at 18 of 25 patients (72%), significant improvement – at 5 of 25 (20%), the effect was absent – 1 patient (4%), deterioration was noted only in 1 case (4%). Efficiency of lamitor in dependence on epilepsy form was considered. Good tolerability of lamitor is noted. Thus, our research demonstrated high efficiency and good tolerability of lamitor as an additional antiepileptic drug and in monotherapy in the treatment of idiopathic epilepsies in children and adolescents

On the Bethe Ansatz for the Jaynes-Cummings-Gaudin model

We investigate the quantum Jaynes-Cummings model - a particular case of the Gaudin model with one of the spins being infinite. Starting from the Bethe equations we derive Baxter's equation and from it a closed set of equations for the eigenvalues of the commuting Hamiltonians. A scalar product in the separated variables representation is found for which the commuting Hamiltonians are Hermitian. In the semi classical limit the Bethe roots accumulate on very specific curves in the complex plane. We give the equation of these curves. They build up a system of cuts modeling the spectral curve as a two sheeted cover of the complex plane. Finally, we extend some of these results to the XXX Heisenberg spin chain.Comment: 16 page

New Formula for the Eigenvectors of the Gaudin Model in the sl(3) Case

We propose new formulas for eigenvectors of the Gaudin model in the \sl(3) case. The central point of the construction is the explicit form of some operator P, which is used for derivation of eigenvalues given by the formula $| w_1, w_2) = \sum_{n=0}^\infty P^n/n! | w_1, w_2,0>$, where $w_1$, $w_2$ fulfil the standard well-know Bethe Ansatz equations