Magneto-optical Kerr effect in Eu1−xCaxB6Eu_{1-x}Ca_{x}B_{6}

We have measured the magneto-optical Kerr rotation of ferromagnetic $Eu_{1-x}Ca_{x}B_{6}$ with x=0.2 and 0.4, as well as of $YbB_{6}$ serving as the non-magnetic reference material. As previously for $EuB_{6}$, we could identify a feature at 1 $eV$ in the Kerr response which is related with electronic transitions involving the localized 4f electron states. The absence of this feature in the data for $YbB_{6}$ confirms the relevance of the partially occupied 4f states in shaping the magneto-optical features of $Eu$-based hexaborides. Disorder by $Ca$-doping broadens the itinerant charge carrier contribution to the magneto-optical spectra

4f-spin dynamics in La(2-x-y)Sr(x)Nd(y)CuO(4)

We have performed inelastic magnetic neutron scattering experiments on La(2-x-y)Sr(x)Nd(y)CuO(4) in order to study the Nd 4f-spin dynamics at low energies. In all samples we find at high temperatures a quasielastic line (Lorentzian) with a line width which decreases on lowering the temperature. The temperature dependence of the quasielastic line width Gamma/2(T) can be explained with an Orbach-process, i.e. a relaxation via the coupling between crystal field excitations and phonons. At low temperatures the Nd-4f magnetic response S(Q,omega) correlates with the electronic properties of the CuO(2)-layers. In the insulator La(2-y)Nd(y)CuO(4) the quasielastic line vanishes below 80 K and an inelastic excitation occurs. This directly indicates the splitting of the Nd3+ ground state Kramers doublet due to the static antiferromagnetic order of the Cu moments. In La(1.7-x)Sr(x)Nd(0.3)CuO(4) with x = 0.12, 0.15 and La(1.4-x)Sr(x)Nd(0.6)CuO(4) with x = 0.1, 0.12, 0.15, 0.18 superconductivity is strongly suppressed. In these compounds we observe a temperature independent broad quasielastic line of Gaussian shape below T about 30 K. This suggests a distribution of various internal fields on different Nd sites and is interpreted in the frame of the stripe model. In La(1.8-y)Sr(0.2)Nd(y)CuO(4) (y = 0.3, 0.6) such a quasielastic broadening is not observed even at lowest temperature.Comment: 8 pages, 10 figures included, to appear in Phys. Rev.

Anomalous Low Temperature Behavior of Superconducting Nd(1.85)Ce(0.15)CuO(4-y)

We have measured the temperature dependence of the in-plane London penetration depth lambda(T) and the maximum Josephson current Ic(T) using bicrystal grain boundary Josephson junctions of the electron-doped cuprate superconductor Nd(1.85)Ce(0.15)CuO(4-y). Both quantities reveal an anomalous temperature dependence below about 4 K. In contrast to the usual monotonous decrease (increase) of lambda(T) (Ic(T)) with decreasing temperature, lambda(T) and Ic(T) are found to increase and decrease, respectively, with decreasing temperature below 4 K resulting in a non-monotonous overall temperature dependence. This anomalous behavior was found to be absent in analogous measurements performed on Pr(1.85)Ce(0.15)CuO(4-y). From this we conclude that the anomalous behavior of Nd(1.85)Ce(0.15)CuO(4-y) is caused by the presence of the Nd3+ paramagnetic moments. Correcting the measured lambda(T) dependence of Nd(1.85)Ce(0.15)CuO(4-y) for the temperature dependent susceptibility due to the Nd moments, an exponential dependence is obtained indicating isotropic s-wave pairing. This result is fully consistent with the lambda(T) dependence measured for Pr(1.85)Ce(0.15)CuO(4-y).Comment: 4 pages including 4 figures, to appear in Phys. Rev. Let

Electronic transport in EuB6_6

EuB$_6$ is a magnetic semiconductor in which defects introduce charge carriers into the conduction band with the Fermi energy varying with temperature and magnetic field. We present experimental and theoretical work on the electronic magnetotransport in single-crystalline EuB$_6$. Magnetization, magnetoresistance and Hall effect data were recorded at temperatures between 2 and 300 K and in magnetic fields up to 5.5 T. The negative magnetoresistance is well reproduced by a model in which the spin disorder scattering is reduced by the applied magnetic field. The Hall effect can be separated into an ordinary and an anomalous part. At 20 K the latter accounts for half of the observed Hall voltage, and its importance decreases rapidly with increasing temperature. As for Gd and its compounds, where the rare-earth ion adopts the same Hund's rule ground state as Eu$^{2+}$ in EuB$_{6}$, the standard antisymmetric scattering mechanisms underestimate the $size$ of this contribution by several orders of magnitude, while reproducing its $shape$ almost perfectly. Well below the bulk ferromagnetic ordering at $T_C$ = 12.5 K, a two-band model successfully describes the magnetotransport. Our description is consistent with published de Haas van Alphen, optical reflectivity, angular-resolved photoemission, and soft X-ray emission as well as absorption data, but requires a new interpretation for the gap feature deduced from the latter two experiments.Comment: 35 pages, 12 figures, submitted to PR

Acceptability and feasibility of peer assisted supervision and support for intervention practitioners: a Q-methodology evaluation

Evidence-based interventions often include quality improvement methods to support fidelity and improve client outcomes. Clinical supervision is promoted as an effective way of developing practitioner confidence and competence in delivery; however, supervision is often inconsistent and embedded in hierarchical line management structures that may limit the opportunity for reflective learning. The Peer Assisted Supervision and Support (PASS) supervision model uses peer relationships to promote the self-regulatory capacity of practitioners to improve intervention delivery. The aim of the present study was to assess the acceptability and feasibility of PASS amongst parenting intervention practitioners. A Q-methodology approach was used to generate data and 30 practitioners volunteered to participate in the study. Data were analyzed and interpreted using standard Q-methodology procedures and by-person factor analysis yielded three factors. There was consensus that PASS was acceptable. Participants shared the view that PASS facilitated an environment of support where negative aspects of interpersonal relationships that might develop in supervision were not evident. Two factors represented the viewpoint that PASS was also a feasible model of supervision. However, the third factor was comprised of practitioners who reported that PASS could be time consuming and difficult to fit into existing work demands. There were differences across the three factors in the extent to which practitioners considered PASS impacted on their intervention delivery. The findings highlight the importance of organizational mechanisms that support practitioner engagement in supervision

Evaluating the effects of multisystemic therapy for adolescents with intellectual disabilities and antisocial or delinquent behaviour and their parents

Background: An adaptation of multisystemic therapy (MST) was piloted to find out whether it would yield better outcomes than standard MST in families where the adolescent not only shows antisocial or delinquent behaviour, but also has an intel‐ lectual disability. Method: To establish the comparative effectiveness of MST‐ID (n = 55) versus stand‐ ard MST (n = 73), treatment outcomes were compared at the end of treatment and at 6‐month follow‐up. Pre‐treatment differences were controlled for using the propen‐ sity score method. Results: Multisystemic therapy‐ID resulted in reduced police contact and reduced rule breaking behaviour that lasted up to 6 months post‐treatment. Compared to standard MST, MST‐ID more frequently resulted in improvements in parenting skills, family relations, social support, involvement with pro‐social peers and sustained pos‐ itive behavioural changes. At follow‐up, more adolescents who had received MST‐ID were still living at home. Conclusions: These results support further development of and research into the MST‐ID adaptation

Psychosocial Treatment of Children in Foster Care: A Review

A substantial number of children in foster care exhibit psychiatric difficulties. Recent epidemiologi-cal and historical trends in foster care, clinical findings about the adjustment of children in foster care, and adult outcomes are reviewed, followed by a description of current approaches to treatment and extant empirical support. Available interventions for these children can be categorized as either symptom-focused or systemic, with empirical support for specific methods ranging from scant to substantial. Even with treatment, behavioral and emotional problems often persist into adulthood, resulting in poor functional outcomes. We suggest that self-regulation may be an important mediat-ing factor in the appearance of emotional and behavioral disturbance in these children