Search

Objectives--Chronic migraine (CM), previously called transformed migraine, is a frequent headache disorder that affects 2%-3% of the general population. Analgesic overuse, insomnia, depression, and anxiety are disorders that are often [...]

Ceramics based on (1-x)La(Mg1/2Ti1/2)O3 (LMT)–xATiO3 solid solutions, where A=Ca, Sr, and Ba, have been investigated to study the effect of average A-site ionic radius on structure and microwave dielectric properties. X-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy were used to study the structural changes and planar defects and thereby interpret changes in microwave properties. 1:1 rocksalt ordering between Mg2+ and Ti4+ in LMT was destroyed for all samples in which x>0.1. XRD and TEM revealed that all (1-x)LMT–xCaTiO3 (LMTCT), x<=0.9, were distorted through a combination of antiphase and in-phase octahedral rotations (tilted). For (1-x)LMT–xSrTiO3 (LMTST) this combination is present until x=0.5, and for x>0.5 only antiphase tilting exists. For (1-x)LMT–xBaTiO3 (LMTBT), in-phase and antiphase octahedral distortions were only present for x<=0.3, x=0.5 was tilted in antiphase and x>=0.7 was untilted. The temperature coefficient of resonant frequency (τf) varied linearly with relative permittivity ([variant_greek_epsilon]r) for LMTCT and LMTST but a discontinuity was observed for LMTBT at x≈0.7, the composition at which octahedral rotations are no longer present at room temperature. Zero τf was achieved at x≈0.5 in all solid solution series. In general, the microwave dielectric quality factor (Qfo) decreased with increasing x to a minimum at x=0.5 for all solid solution series followed by an increase at x=0.7 despite [variant_greek_epsilon]r being higher for x=0.7 than for 0.5. Qfo then continued to decrease as x=1 was approached and [variant_greek_epsilon]r increased. [ABSTRACT FROM AUTHOR]

Recruitment of the limpet Patella ulyssiponensis was investigated in relation to the presence of living crustose coralline algae (CCA) in rocky-shore habitats. Juvenile limpets (≤10 mm maximum shell length) were counted in CCA-present and CCA-absent habitats, on three shores in SW Portugal during summer 2007 and winter 2009. Furthermore, the settling response of laboratory-reared larvae of P. ulyssiponensis to CCA-covered substratum, and bare-rock, was examined. Across the intertidal zone, we found a clear association between the distribution and abundance of juveniles and the presence of CCA. Although the presence of CCA was not an absolute requisite for juvenile occurrence, null juvenile densities were mostly recorded in CCA-absent areas. The highest juvenile densities (maximum of 64 individuals in 15 × 15 cm) were consistently found in CCA-dominated habitats, namely steep wave-exposed areas at low-shore and rock-pools. The hypothesis of CCA-enhanced settlement was not supported, as settlement intensities of laboratory-reared larvae were similar between chips of rock encrusted by CCA and chips of bare-rock. From the overall number of settlers onto CCA-encrusted rock chips, 51% were found in tiny pits lacking CCA. This was the first study of the settlement patterns of larvae of the genus Patella using naturally occurring rocky substrata. These results are preliminary and should be confirmed with choice-experiments and improved monitoring of the position of settlers. We suggest that CCA plays a role in the recruitment of P. ulyssiponensis , potentially promoting survivorship of early benthic stages, but possibly not enhancing settlement. [ABSTRACT FROM AUTHOR]