Ecology of Thioploca spp.: Nitrate and sulfur storage in relation to chemical microgradients and influence of Thioploca spp. on the sedimentary nitrogen cycle

Microsensors, including a recently developed NO3 − biosensor, were applied to measure O2 and NO3 − profiles in marine sediments from the upwelling area off central Chile and to investigate the influence of Thioploca spp. on the sedimentary nitrogen metabolism. The studies were performed in undisturbed sediment cores incubated in a small laboratory flume to simulate the environmental conditions of low O2, high NO3 −, and bottom water current. On addition of NO3 −and NO2 −, Thioploca spp. exhibited positive chemotaxis and stretched out of the sediment into the flume water. In a core densely populated with Thioploca, the penetration depth of NO3 − was only 0.5 mm and a sharp maximum of NO3 − uptake was observed 0.5 mm above the sediment surface. In sediments with only fewThioploca spp., NO3 − was detectable down to a depth of 2 mm and the maximum consumption rates were observed within the sediment. No chemotaxis toward nitrous oxide (N2O) was observed, which is consistent with the observation that Thioploca does not denitrify but reduces intracellular NO3 − to NH4 +. Measurements of the intracellular NO3 − and S0 pools inThioploca filaments from various depths in the sediment gave insights into possible differences in the migration behavior between the different species. Living filaments containing significant amounts of intracellular NO3 − were found to a depth of at least 13 cm, providing final proof for the vertical shuttling of Thioploca spp. and nitrate transport into the sediment

Astrophysics in 2006

The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the universe) and others of which there are always many, like meteors and molecules, black holes and binaries.Comment: 244 pages, no figure

Exercise on Prescription: trial protocol and evaluation of outcomes

BACKGROUND: In many countries exercise prescriptions are used in an attempt to initiate a physically active lifestyle in sedentary populations. Previous studies have primarily evaluated low intensive exercise prescription interventions and found moderately positive effects on physical activity and aerobic fitness. In a highly intensive Danish exercise prescription scheme called 'Exercise on Prescription' (EoP) the general practitioners can prescribe EoP to sedentary patients with lifestyle diseases. The aim of this randomized trial is to assess the short- and long-term effects of the EoP scheme. Thus, the aim of this paper is to describe the randomized controlled trial designed for evaluating effectiveness of EoP, and to present results from validations of outcome measures. METHODS/DESIGN: EoP involves a 16-week supervised training intervention and five counselling sessions (health profiles). All patients referred to EoP were eligible for the trial and were offered participation during the baseline health profile. Comparisons between the EoP group and the control group were made at baseline, and after four and ten months. Physiological measures used were maximal oxygen uptake (VO(2)max), glycosylated haemoglobin (HbA1c), bodyweight, and BMI. Patient-reported measures used were physical activity, health-related quality of life, amount and intensity of exercise, compliance with national guidelines for physical activity, and physical fitness. The validation of the cycle ergometer test found a strong correlation between maximal work capacity and VO(2)max, and acceptable test-retest reliability at group level. Calibration of the HbA1c apparatus was stable over ten weeks with minimal use, and test-retest reliability was good. High agreement percents were found for test-retest reliability for the self-administered questionnaire. DISCUSSION: The trial is designed to provide information about the effectiveness of the EoP scheme. The trial is part of a health technology assessment of EoP, which besides the effectiveness covers the patient perspective, the organization, and the health economy. All three methods validated were found useful for the EoP trial

10 Gb/s bidirectional single fibre long reach PON link with distributed Raman amplification

We report operation of a single fibre bidirectional 80 km long reach PON link with symmetric up-and-downstream data rate of 10 Gb/s supported by distributed Raman fibre amplification only

The 3-D Structure of SN 1987A's inner Ejecta

Twenty years after the explosion of SN 1987A, we are now able to observe the three-dimensional spatially resolved inner ejecta. Detailed mapping of newly synthesised material and its radioactive decay daughter products sheds light on the explosion mechanism. This may reveal the geometry of the explosion and its connection to the equatorial ring and the outer rings around SN 1987A. We have used integral field spectroscopy to image the supernova ejecta and the equatorial ring in the emission lines of [Si I]+[Fe II] and He I. The spectral information can be mapped into a radial velocity image revealing the expansion of the ejecta both as projected onto the sky and perpendicular to the sky plane. The inner ejecta are spatially resolved in a North-South direction and are clearly asymmetric. We argue that the bulk of the ejecta is situated in the same plane as defined by the equatorial ring and does not form a bipolar structure as has been suggested. The exact shape of the ejecta is modelled and we find that an elongated triaxial ellipsoid fits the observations best. From our spectral analyses of the ejecta spectrum we find that most of the He I, [Si I] and [Fe I-II] emission originates in the core material which has undergone explosive nucleosynthesis. The He I emission may be the result of alpha-rich freeze-out if the positron energy is deposited locally. Our observations clearly indicate a non-symmetric explosion mechanism for SN 1987A. The elongation and velocity asymmetries point towards a large-scale spatial non-spherical distribution as predicted in recent explosion models. The orientation of the ejecta in the plane of the equatorial ring argues against a jet-induced explosion through the poles due to stellar rotation.Comment: Above abstract is abridged. 11 pages, 9 figures. Accepted July 1st 2010 by Astronomy and Astrophysic