Ladder operators for subtle hidden shape invariant potentials

Ladder operators can be constructed for all potentials that present the integrability condition known as shape invariance, satisfied by most of the exactly solvable potentials. Using the superalgebra of supersymmetric quantum mechanics we construct the ladder operators for two exactly solvable potentials that present a subtle hidden shape invariance.Comment: 9 pages, based on the talk given at International Conference Progress in Supersymmetric Quantum Mechanics (PSQM03), Valladolid, Spain, 15-19 July, 2003, to appear in a Special Issue of J. Phys. A: Math. Ge

Generalized Ladder Operators for Shape-invariant Potentials

A general form for ladder operators is used to construct a method to solve bound-state Schr\"odinger equations. The characteristics of supersymmetry and shape invariance of the system are the start point of the approach. To show the elegance and the utility of the method we use it to obtain energy spectra and eigenfunctions for the one-dimensional harmonic oscillator and Morse potentials and for the radial harmonic oscillator and Coulomb potentials.Comment: in Revte

Upper critical magnetic field in K0.83Fe1.83Se2 and Eu0.5K0.5Fe2As2 single crystals

The H-T phase diagrams of single crystalline electron-doped K0.83Fe1.83Se2 (KFS1), K0.8Fe2Se2 (KFS2) and hole-doped Eu0.5K0.5Fe2As2 (EKFA) have been deduced from tunnel diode oscillator-based contactless measurements in pulsed magnetic fields up to 57 T for the inter-plane (H//c) and in-plane (H//ab) directions. The temperature dependence of the upper critical magnetic field Hc2(T) relevant to EFKA is accounted for by the Pauli model including an anisotropic Pauli paramagnetic contribution (\mu_BHp=114 T for H//ab and 86 T for H//c). This is also the case of KFS1 and KFS2 for H//ab whereas a significant upward curvature, accounted for by a two-gap model, is observed for H//c. Despite the presence of antiferromagnetic lattice order within the superconducting state of the studied compounds, no influence of magnetic ordering on the temperature dependence of Hc2(T) is observed.Comment: 9 pages, 5 figures. arXiv admin note: text overlap with arXiv:1104.561

Quenched nematic criticality separating two superconducting domes in an iron-based superconductor under pressure

The nematic electronic state and its associated nematic critical fluctuations have emerged as potential candidates for superconducting pairing in various unconventional superconductors. However, in most materials their coexistence with other magnetically-ordered phases poses significant challenges in establishing their importance. Here, by combining chemical and hydrostatic physical pressure in FeSe$_{0.89}$S$_{0.11}$, we provide a unique access to a clean nematic quantum phase transition in the absence of a long-range magnetic order. We find that in the proximity of the nematic phase transition, there is an unusual non-Fermi liquid behavior in resistivity at high temperatures that evolves into a Fermi liquid behaviour at the lowest temperatures. From quantum oscillations in high magnetic fields, we trace the evolution of the Fermi surface and electronic correlations as a function of applied pressure. We detect experimentally a Lifshitz transition that separates two distinct superconducting regions: one emerging from the nematic electronic phase with a small Fermi surface and strong electronic correlations and the other one with a large Fermi surface and weak correlations that promotes nesting and stabilization of a magnetically-ordered phase at high pressures. The lack of mass divergence suggests that the nematic critical fluctuations are quenched by the strong coupling to the lattice. This establishes that superconductivity is not enhanced at the nematic quantum phase transition in the absence of magnetic order.Comment: 4 figures, 9 page

Order of strength exercises on the performance of judo athletes

OBJETIVO: El objetivo fue investigar el efecto del orden distintas de ejercicios de fuerza para extremidades superiores e inferiores en el rendimiento específico de judokas junior. MÉTODO: Se divide una muestra de 39 atletas masculinos en tres grupos: Experimental-EG1; EG2 y Control. Los Grupos realizaron ejercicios de fuerza máxima y potencia con intensidades del 80-90% para 12 semanas de intervención. El orden de los ejercicios para el EG1 fue del de extremidades superiores primero e inferiores después. El EG2 realiza los mismos ejercicios en secuencia inversa. Se utilizó la Prueba Especial Judo Fitness (SJFT) para evaluación. RESULTADOS: Los experimentos intra e inter grupos muestran diferencias (p<0.05) en los derribos-caídas y en el índice SJFT, con EG2 mostrando mejores resultados. CONCLUSIONES: Las variables de SJFT tuvieron mejores resultados en el orden de ejercicios seguidos por el EG2OBJECTIVE: To analyze the effect of strength exercises using different orders for upper and lower limbs on the specific performance of junior judo athletes. METHODS: 39 male athletes were divided into three groups: experimental- EG1, experimental-EG2 and control group. Experimental groups performed with intensities 80-90% of strength and power for 12 weeks. The exercise-order for EG1 followed an upper to lower limb sequence and EG2 performed the same exercises in reverse. The Special Judo Fitness Test (SJFT) was used in the assessment. RESULTS: Experimental intra and inter-groups showed differences (p<0.05) in the throws-falls and SJFT-index, but the EG2 showed best results. CONCLUSIONS: The SJFT-variables had better results to exercises order in EG

Upper critical magnetic field in Ba_0.68K_0.32Fe_2As_2 and Ba(Fe_0.93Co_0.07)_2As_2

We report measurements of the temperature dependence of the radio-frequency magnetic penetration depth in Ba_0.68K_0.32Fe_2As_2 and Ba(Fe_0.93Co_0.07)_2As_2 single crystals in pulsed magnetic fields up to 60 T. From our data, we construct an H-T phase diagram for the inter-plane (H || c) and in-plane (H || ab) directions for both compounds. For both field orientations in Ba_0.68K_0.32Fe_2As_2, we find a concave curvature of the Hc2(T) lines with decreasing anisotropy and saturation towards lower temperature. Taking into account Pauli spin paramagnetism we can describe Hc2(T) and its anisotropy. In contrast, we find that Pauli paramagnetic pair breaking is not essential for Ba(Fe_0.93Co_0.07)_2As_2. For this electron-doped compound, the data support a Hc2(T) dependence that can be described by the Werthamer Helfand Hohenberg model for H || ab and a two-gap behavior for H || c.Comment: 7 pages, 8 figure

A Randomized Clinical Trial Investigating an Integrated Nursing Educational Program to Mitigate Chemotherapy-Induced Nausea and Vomiting in Cancer Patients: The NIV-EC Trial

Background: In addition to pharmacological prevention, chemotherapy-induced nausea and vomiting (CINV) can be mitigated through patient education; written supporting materials can be beneficial. Methods: This is a randomized, controlled trial which randomly assigned patients undergoing first chemotherapy cycle to receive oral information regarding CINV prevention and management (control arm) or oral information plus an informative booklet (experimental arm). Overall, 384 cancer patients fulfilling the following inclusion criteria were enrolled: age ≥18 years; life expectancy ≥6 months; no cognitive impairment; written informed consent. After the first cycle, CINV occurrence and its impact on daily activities were assessed using the Functional Living Index Emesis (FLIE). Results: Severe nausea was self-reported by 3.0% and 10.8% of patients in the experimental and control group, respectively (difference: 7.8%; 95% confidence interval: 2.3% to 13.1%). Moderate/high impact of nausea on daily activities was lower in patients also receiving the booklet than in the control group (4.2% and 10.1%, respectively; difference: 5.9%; 95% confidence interval: 0.3% to 11.5%). Vomiting was not statistically different between study arms. Conclusions: This integrated nursing approach was effective in aiding cancer patients in CINV self-management. Although the beneficial effect was moderate, this intervention demands minimal resources in terms of costs and time

Evidence for antiferromagnetism coexisting with charge order in the trilayer cuprate HgBa2_2Ca2_2Cu3_3O8+δ_{8+ \delta}

Multilayered cuprates possess not only the highest superconducting temperature transition but also offer a unique platform to study disorder-free CuO$_2$ planes and the interplay between competing orders with superconductivity. Here, we study the underdoped trilayer cuprate HgBa$_2$Ca$_2$Cu$_3$O$_{8+ \delta}$ and we report the first quantum oscillation and Hall effect measurements in magnetic field up to 88 T. A careful analysis of the complex spectra of quantum oscillations strongly supports the coexistence of an antiferromagnetic order in the inner plane and a charge order in the outer planes. The presence of an ordered antiferromagnetic metallic state that extends deep in the superconducting phase is a key ingredient that supports magnetically mediated pairing interaction in cuprates.Comment: 6+5 pages, 4+6 figure