Fabrication of optical planar waveguides in KY(WO4)2KY(WO_4)_2 by He-ion implantation

In this paper, planar waveguides produced by He-ion implantation have been demonstrated in undoped and Yb-doped KY(WO/sub 4/)/sub 2/ crystals. The effective refractive indices of guided modes in surface planar waveguides were measured by dark m-line spectroscopy and the refractive index profiles were reconstructed by calculations based on the inverse WKB method. The end-faces of implanted crystals were polished and the waveguiding properties of the obtained planar structures were investigated using a laser diode at 980 nm and a CCD camera

Fabrication of optical planar and channel waveguides in Yb³⁺ doped KY(WO₄)₂ by He-ion implantation

Light ion implantation can be regarded as a universal tool for fabricating low-loss waveguide structures in optically active oxide materials. We have fabricated planar optical waveguides in $KY(WO_4)_2$:(2%)$Yb^{3+}$ crystals by implanting He+ ions at 1.5 MeV, with doses ranging from 1 to 3x10^16 ions/cm2. An optical barrier with a decreased effective refractive index was created at the end of the ions' tracks, situated approximately 3.5 μm below the surface. The change in refractive index with respect to the bulk value and its stability to thermal treatment were investigated by dark m-line spectroscopy. Surface channel waveguides were obtained by writing sidewalls into the planar guiding layer by implantation through a slit. The sidewalls were produced by keeping the ion energy fixed and varying the incident angle of implantation. Channel waveguides of 5-μm width and 4-μm depth were obtained in the regions between the implanted sidewalls. Beam-propagation parameters were measured by investigating the output profile of end-coupled, fundamental-mode laser light at 980 nm. The results of loss measurements will be presented at the conference

Legitimacy Judgments about Corporate Tax Avoidance: A Deliberation Experiment

Previous research has suggested that business firms need to engage in active dialogues with stakeholders to maintain their legitimacy. We investigate this “legitimation-as-deliberation” thesis in the context of global tax avoidance and explore whether and under what conditions deliberation leads to the legitimation or delegitimation of tax avoidance and the consultancies involved in facilitating tax avoidance. By conducting an experiment in which study participants discussed the issue of global tax avoidance with representatives of a tax accounting firm and/or representatives of an NGO critical of tax avoidance, we demonstrate that entering deliberations can indeed serve as legitimation strategy for firms. However, the direction and size of the effect depend on the relative persuasiveness of the representatives’ arguments. Moreover, representatives of the tax accounting firm have a stronger impact on participants’ legitimacy judgments about their organization, whereas representatives of the NGO mainly affect participants’ legitimacy judgments regarding the practice. Our study provides three contributions to management research. Phenomenologically, it sheds light on tax avoidance as an important but underexplored topic in management research. Methodologically, it develops an experimental design enabling causal inference about deliberative effects. Finally, theoretically, it conceptualizes legitimacy as a communicative process of making judgments

Time of exposure to social defeat stress during childhood and adolescence and redox dysregulation on long-lasting behavioral changes, a translational study.

Traumatic events during childhood/early adolescence can cause long-lasting physiological and behavioral changes with increasing risk for psychiatric conditions including psychosis. Genetic factors and trauma (and their type, degree of repetition, time of occurrence) are believed to influence how traumatic experiences affect an individual. Here, we compared long-lasting behavioral effects of repeated social defeat stress (SD) applied during either peripuberty or late adolescence in adult male WT and Gclm-KO mice, a model of redox dysregulation relevant to schizophrenia. As SD disrupts redox homeostasis and causes oxidative stress, we hypothesized that KO mice would be particularly vulnerable to such stress. We first found that peripubertal and late adolescent SD led to different behavioral outcomes. Peripubertal SD induced anxiety-like behavior in anxiogenic environments, potentiated startle reflex, and increased sensitivity to the NMDA-receptor antagonist, MK-801. In contrast, late adolescent SD led to increased exploration in novel environments. Second, the long-lasting impact of peripubertal but not late adolescent SD differed in KO and WT mice. Peripubertal SD increased anxiety-like behavior in anxiogenic environments and MK-801-sensitivity mostly in KO mice, while it increased startle reflex in WT mice. These suggest that a redox dysregulation during peripuberty interacts with SD to remodel the trajectory of brain maturation, but does not play a significant role during later SD. As peripubertal SD induced persisting anxiety- and fear-related behaviors in male mice, we then investigated anxiety in a cohort of 89 early psychosis male patients for whom we had information about past abuse and clinical assessment during the first year of psychosis. We found that a first exposure to physical/sexual abuse (analogous to SD) before age 12, but not after, was associated with higher anxiety at 6-12 months after psychosis onset. This supports that childhood/peripuberty is a vulnerable period during which physical/sexual abuse in males has wide and long-lasting consequences

Spatio-Temporal Pattern of Saturn's Equatorial Oscillation

Recent ground-based and Cassini CIRS thermal-infrared data have characterized the spatial and temporal characteristics of an equatorial oscillation in the middle atmosphere of Saturn above the 100-mbar level. The CIRS data [I] indicated a pattern of warm and cold anomalies near the equator, stacked vertically in alternating fashion. The ground-based observations s2, although not having the altitude range or vertical resolution of the CIRS observations, covered several years and indicated an oscillation cycle of approx.15 years, roughly half of Saturn's year. In Earth's middle atmosphere, both the quasi-biennial (approx.26 months) and semi-annual equatorial oscillations have been extensively observed and studied (see e.g., [3]), These exhibit a pattern of alternating warmer and cooler zonal-mean temperatures with altitude, relative to those at subtropical latitudes. Consistent with the thermal wind equation, this is also associated with an alternating pattern of westerly and easterly zonal winds. Moreover, the pattern of winds and temperatures descends with time. Momentum deposition by damped vertically propagating waves is thought to play a key role m forcing both types of oscillation, and it can plausibly account for the descent. Here we report the direct observation of this descent in Saturn's equatorial atmosphere from Cassini radio occultation soundings in 2005 and 2009. The retrieved temperatures are consistent with a descent of 0.7 x the pressure scale height. The descent rate is related to the magnitude of the wave forcing, radiative damping, and induced meridional circulations. We discuss possible implications

From Quantum Universal Enveloping Algebras to Quantum Algebras

The ``local'' structure of a quantum group G_q is currently considered to be an infinite-dimensional object: the corresponding quantum universal enveloping algebra U_q(g), which is a Hopf algebra deformation of the universal enveloping algebra of a n-dimensional Lie algebra g=Lie(G). However, we show how, by starting from the generators of the underlying Lie bialgebra (g,\delta), the analyticity in the deformation parameter(s) allows us to determine in a unique way a set of n ``almost primitive'' basic objects in U_q(g), that could be properly called the ``quantum algebra generators''. So, the analytical prolongation (g_q,\Delta) of the Lie bialgebra (g,\delta) is proposed as the appropriate local structure of G_q. Besides, as in this way (g,\delta) and U_q(g) are shown to be in one-to-one correspondence, the classification of quantum groups is reduced to the classification of Lie bialgebras. The su_q(2) and su_q(3) cases are explicitly elaborated.Comment: 16 pages, 0 figures, LaTeX fil

Pharmacokinetic parameter sets of alfentanil revisited: optimal parameters for use in target controlled infusion and anaesthesia display systems

Background In open TCI and anaesthesia display systems, the choice of pharmacokinetic (PK) parameter sets of opioids is clinically relevant. Accuracy and bias of the PK models may be affected by administration mode and the co-administered hypnotic drug. We retrospectively evaluated the performance of eight PK parameter sets for alfentanil in two data sets (infusion and bolus application). Methods With the dosing history from two studies in orthopaedic patients anaesthetized with propofol or inhalation anaesthetics the alfentanil plasma concentration over time was calculated with eight PK parameter sets. Median absolute performance error (MDAPE), log accuracy, median performance error (MDPE), log bias, Wobble, and Divergence were computed. Mann-Whitney rank test with Bonferroni correction was used for comparison between bolus and infusion data, repeated measures analysis of variance on ranks was used for comparison among parameter sets. Results The parameters by Scott (original and weight adjusted) and Fragen had a MDAPE ≤30% and a median log accuracy <0.15 independent of the administration mode, while MDPE was within ±20% and log bias nearly within ±0.1, respectively. The sets by Maitre and Lemmens were within these limits only in the bolus data. All other parameter sets were outside these limits. Conclusions In healthy orthopaedic patients, the PK parameters by Scott and by Maitre were equally valid when alfentanil was given as repeated boluses. When given as infusion, the Maitre parameters were less accurate and subject to a significant bias. We cannot exclude that the difference between bolus and infusion is partially because of the different hypnotics use