Optomechanical entanglement between a movable mirror and a cavity field.

We show how stationary entanglement between an optical cavity field mode and a macroscopic vibrating mirror can be generated by means of radiation pressure. We also show how the generated optomechanical entanglement can be quantified, and we suggest an experimental readout scheme to fully characterize the entangled state. Surprisingly, such optomechanical entanglement is shown to persist for environment temperatures above 20 K using state-of-the-art experimental parameters.

Self-cooling of a micromirror by radiation pressure.

Cooling of mechanical resonators is currently a popular topic in many fields of physics including ultra-high precision measurements, detection of gravitational waves and the study of the transition between classical and quantum behaviour of a mechanical system. Here we report the observation of self-cooling of a micromirror by radiation pressure inside a high-finesse optical cavity. In essence, changes in intensity in a detuned cavity, as caused by the thermal vibration of the mirror, provide the mechanism for entropy flow from the mirror's oscillatory motion to the low-entropy cavity field. The crucial coupling between radiation and mechanical motion was made possible by producing free-standing micromirrors of low mass (m approximately 400 ng), high reflectance (more than 99.6%) and high mechanical quality (Q approximately 10,000). We observe cooling of the mechanical oscillator by a factor of more than 30; that is, from room temperature to below 10 K. In addition to purely photothermal effects we identify radiation pressure as a relevant mechanism responsible for the cooling. In contrast with earlier experiments, our technique does not need any active feedback. We expect that improvements of our method will permit cooling ratios beyond 1,000 and will thus possibly enable cooling all the way down to the quantum mechanical ground state of the micromirror.

Modern freshwater microbialite analogues for ancient dendritic reef structures.

Microbialites are organosedimentary structures that can be constructed by a variety of metabolically distinct taxa. Consequently, microbialite structures abound in the fossil record, although the exact nature of the biogeochemical processes that produced them is often unknown. One such class of ancient calcareous structures, Epiphyton and Girvanella, appear in great abundance during the Early Cambrian. Together with Archeocyathids, stromatolites and thrombolites, they formed major Cambrian reef belts. To a large extent, Middle to Late Cambrian reefs are similar to Precambrian reefs, with the exception that the latter, including terminal Proterozoic reefs, do not contain Epiphyton or Girvanella. Here we report the discovery in Pavilion Lake, British Columbia, Canada, of a distinctive assemblage of freshwater calcite microbialites, some of which display microstructures similar to the fabrics displayed by Epiphyton and Girvanella. The morphologies of the modern microbialites vary with depth, and dendritic microstructures of the deep water (> 30 m) mounds indicate that they may be modern analogues for the ancient calcareous structures. These microbialites thus provide an opportunity to study the biogeochemical interactions that produce fabrics similar to those of some enigmatic Early Cambrian reef structures.

[Prenatal diagnosis of congenital cystic neck hygroma. Comparison of sonographic and computed tomography findings]. / Die pränatale Diagnose eines Hygroma cysticum colli congenitum. Ein Vergleich sonographischer und computer-tomographischer Befunde.

In a case of prenatal diagnosis of lymphangioma (hygroma) of the neck the results of sonographic and computer tomographic investigations were compared. It was shown that the methods are complimentary and lead to very similar conclusions. The first investigation should be by ultra-sound because of the lack of radiation. The computer tomography is then indicated with specific questions in mind and the radiation exposure can be minimized. In the presented case the combination of sonography and computer tomography permitted a prognosis of poor operability of the lesion. Since the prognosis cannot be determined with complete certainty prior to delivery the obstetrician and neonatalogist need to proceed with the possibility of a treatable anomaly in mind. The neckopsy findings in our case confirmed the inoperability of the lesion.

[Experiences in the assessment of the subpartal cardiotocogram (author's transl)]. / Erfahrungen bei der Bewertung des subpartalen Kardiotokogramms.

750 cardiotocographic curves of the last 30 minutes prior to vaginal delivery were assessed retrospectively according to the CTG score after Hammacher et al. (6). The aim of this study was to examine the prognostic value of the CTG score with regard to the foetal acid-base stains. The results obtained showed a distinct interdependence between the CTG score and the risk of foetal acidosis. Correct interpretation of the CTG can be ensured only if all three different CTG parameters are considered. The most frequent and reliable pointers to the existence of foetal acidosis are the occurrence of severe variable or late decelerations which can be detected from an examination of the floating-line pattern.

[Quantitative estimation of cationic leukocyte antigen (cla) and lysozyme in leukaemic leukocytes (author's transl)]. / Die kationischen lysosomalen Proteine der weissen Blutzellen: Quantitative Bestimmung von Kationischem Leukozytenantigen (CLA) und Lysozym in Leukozytenlysaten bei Leukämien.

Cationic lysosomal proteins such as cationic leukocyte antigen (CLA) and lysozyme were estimated in leukocyte lysates of acute and chronic leukaemics using quantitative enzymatic and immunoprecipitation techniques. The studies demonstrate that both lysosomal conponents are markers of non-lymphatic leukaemias. Therefore the determination of CLA and lysozyme is valuable for the differential diagnosis of acute leukaemias. The intracellular cationic protein contents showed characteristic kinetic variations as showing during X-irradiation of the spleen in cases of chronic myelocytic leukaemia. White cells in leukocytosis could be distinguished from normals by remarkably low cationic protein contents in leukocyte lysates. The results are interpreted in the light of current results revealed by immunofluorescent analyses.