The physiology of the filamentous bacterium Microthrix parvicella

A study has been made of the physiology of Microthrix parvicella. This filamentous bacterium often causes poor settleability of activated sludge in oxidation ditches supplied with domestic sewage. The organism was found to utilize only long chain fatty acids (preferably in esterified form) as carbon and energy source. Short chain fatty acids and glycerol are only utilized together with long chain fatty acids; other organic substrates are not consumed. The organism requires ammonium salts and reduced-sulphur compounds for growth. Thiamin and cyanocobalamin were found to be essential vitamins. Optimum temperature is 25°C and the pH of the medium has to be above 7. During the early growth phase in batch culture with an oleic acid ester (Tween 80) as the limiting substrate , M. parvicella stores large amount of lipids, mainly oleic acid in esterified form in its cells. In a subsequent period the stored lipids are used for energy supply and synthesis of cell protein.Growth kinetics were studied by cultivating the organism in a chemostat. The maximum specific growth rate was found to be 0.06 h -1 ; the K S value for Tween 80 was too low to be determined. The maximum yield coefficient and the maintenance on Tween 80 were 0.34 g cell dry weight/ g Tween 80 consumed and 6.3 mg Tween 80/g cell dry weight.h, respectively. As only the oleic acid moiety of Tween 80 is consumed, these values must be corrected for the non-fatty acid moiety (76%) of the Tween 80 molecule.Although oleic acid is an excellent substrate for M. parvicella, the organism was found to be inhibited at higher concentrations of this compound. Decreasing pH and decreasing biomass concentration promote the inhibiting action of oleic acid in washed cell suspensions. Various surface-active compounds which are not utilized as carbon source enhance the oxygen uptake rate of washed cells. The increase of the oxygen uptake due to added Tween 80 or oleic acid is probably caused by substrate respiration as well as a non-substrate-specific stimulation caused by surfaceactive properties of these compounds. The affinity for oxygen of M. parvicella is high (K S value &lt; 0.016 mg/l).Abundant growth of M. parvicella was obtained in activated sludge in a bench- scale plant fed with waste water containing oleic acid and supplied with a limited amount of oxygen. These results explain the excessive growth of M.parvicella in activated sludge supplied with raw domestic sewage. This type of sewage contains a considerable amount of fatty matter and the activated-sludge process is usually operated at a low oxygen concentration in the mixed liquor.<p/

ESO Imaging Survey: Infrared Deep Public Survey

This paper presents new J and Ks data obtained from observations conducted at the ESO 3.5m New Technology Telescope using the SOFI camera. These data were taken as part of the ESO Imaging Survey Deep Public Survey (DPS) and significantly extend the earlier optical/infrared EIS-DEEP survey presented in a previous paper. The DPS-IR survey comprises two observing strategies: shallow Ks observations providing nearly full coverage of pointings with complementary multi-band optical data and deeper J and Ks observations of the central parts of these fields. The DPS-IR survey provides a coverage of roughly 2.1 square degrees in Ks with 0.63 square degrees to fainter magnitudes and also covered in J, over three independent regions of the sky. The goal of the present paper is to describe the observations, the data reduction procedures, and to present the final survey products. The astrometric solution with an estimated accuracy of <0.15" is based on the USNO catalog. The final stacked images presented here number 89 and 272, in J and Ks, respectively, the latter reflecting the larger surveyed area. The J and Ks images were taken with a median seeing of 0.77" and 0.8". The images reach a median 5sigma limiting magnitude of J_AB~23.06 in an aperture of 2", while the corresponding limiting magnitude in Ks_AB is ~21.41 and ~22.16 mag for the shallow and deep strategies. Overall, the observed limiting magnitudes are consistent with those originally proposed. The quality of the data has been assessed by comparing the measured magnitude of sources at the bright end directly with those reported by the 2MASS survey and at the faint end by comparing the counts of galaxies and stars with those of other surveys to comparable depth and to model predictions. The final science-grade catalogs and images are available at CDS.Comment: Accepted for publication in A&A, 14 pages, 8 figures, a full resolution version of the paper is available from http://www.astro.ku.dk/~lisbeth/eisdata/papers/5019.pd

Octreotide and hepatocellular carcinoma

[No abstract available

Echelle long-slit optical spectroscopy of evolved stars

We present echelle long-slit optical spectra of a sample of objects evolving off the AGB, most of them in the pre-planetary nebula (pPN) phase, obtained with the ESI and MIKE spectrographs at Keck-II and Magellan-I, respectively. The total wavelength range covered with ESI (MIKE) is ~3900 to 10900 A (~3600 to 7200A). In this paper, we focus our analysis mainly on the Halpha profiles. Prominent Halpha emission is detected in half of the objects, most of which show broad Halpha wings (up to ~4000 km/s). In the majority of the Halpha-emission sources, fast, post-AGB winds are revealed by P-Cygni profiles. In ~37% of the objects Halpha is observed in absorption. In almost all cases, the absorption profile is partially filled with emission, leading to complex, structured profiles that are interpreted as an indication of incipient post-AGB mass-loss. All sources in which Halpha is seen mainly in absorption have F-G type central stars, whereas sources with intense Halpha emission span a larger range of spectral types from O to G. Shocks may be an important excitation agent of the close stellar surroundings for objects with late type central stars. Sources with pure emission or P Cygni Halpha profiles have larger J-K color excess than objects with Halpha mainly in absorption, which suggests the presence of warm dust near the star in the former. The two classes of profile sources also segregate in the IRAS color-color diagram in a way that intense Halpha-emitters have dust grains with a larger range of temperatures. (abridged)Comment: 68 pages, 14 figures, accepted for publication in ApJS (abstract abridged

Observations of the 6 Centimeter Lines of OH in Evolved (OH/IR) Stars

Recent observational and theoretical advances have called into question traditional OH maser pumping models in evolved (OH/IR) stars. The detection of excited-state OH lines would provide additional constraints to discriminate amongst these theoretical models. In this Letter, we report on VLA observations of the 4750 MHz and 4765 MHz lines of OH toward 45 sources, mostly evolved stars. We detect 4765 MHz emission in the star forming regions Mon R2 and LDN 1084, but we do not detect excited-state emission in any evolved stars. The flux density and velocity of the 4765 MHz detection in Mon R2 suggests that a new flaring event has begun.Comment: 4 pages, to appear in ApJ

Burgerschap in het basisonderwijs:Technisch rapport Peil.Burgerschap 2020

Ruimte voor verbetering burgerschapscompetentiesHet niveau van burgerschapscompetenties, burgerschapskennis en -houdingen van groep 8-leerlingen blijkt anno 2020 niet onverdeeld gunstig. Zo beantwoordde een kwart van de leerlingen driekwart van de kennisvragen fout. Een kwart de leerlingen beantwoordde ten minste de helft van de kennisvragen goed. Het niveau van burgerschapskennis van leerlingen blijkt vergeleken met 2009 wat lager. De meerderheid van de leerlingen scoort relatief laag op burgerschapshoudingen.Omvangrijk onderzoek in het basisonderwijsDit blijkt uit Peil.burgerschap, een omvangrijk onderzoek, uitgevoerd door de afdeling Pedagogische en Onderwijswetenschappen van de Universiteit van Amsterdam, het Kohnstamm Instituut, het GION van de Rijksuniversiteit Groningen en het Cito. Aan het onderzoek deden 2.237 groep 8-leerlingen mee van 94 basisscholen. Gegevens zijn verzameld onder leerlingen, leerkrachten en schoolleiders. Peil.burgerschap geeft inzicht in de burgerschapscompetenties van leerlingen en het burgerschapsonderwijs aan het einde van het basisonderwijs. Het maakt onderdeel uit van Peil.onderwijs: een serie periodieke onderzoeken onder de regie van de Inspectie van het Onderwijs naar domeinen van onderwijskwaliteit

SCIAMACHY Level 1 data: calibration concept and in-flight calibration

The calibration of SCIAMACHY was thoroughly checked since the instrument was launched on-board ENVISAT in February 2002. While SCIAMACHY&apos;s functional performance is excellent since launch, a number of technical difficulties have appeared, that required adjustments to the calibration. The problems can be separated into three types: (1) Those caused by the instrument and/or platform environment. Among these are the high water content in the satellite structure and/or MLI layer. This results in the deposition of ice on the detectors in channels 7 and 8 which seriously affects the retrievals in the IR, mostly because of the continuous change of the slit function caused by scattering of the light through the ice layer. Additionally a light leak in channel 7 severely hampers any retrieval from this channel. (2) Problems due to errors in the on-ground calibration and/or data processing affecting for example the radiometric calibration. A new approach based on a mixture of on-ground and in-flight data is shortly described here. (3) Problems caused by principal limitations of the calibration concept, e.g. the possible appearance of spectral structures after the polarisation correction due to unavoidable errors in the determination of atmospheric polarisation. In this paper we give a complete overview of the calibration and problems that still have to be solved. We will also give an indication of the effect of calibration problems on retrievals where possible. Since the operational processing chain is currently being updated and no newly processed data are available at this point in time, for some calibration issues only a rough estimate of the effect on Level 2 products can be given. However, it is the intention of this paper to serve as a future reference for detailed studies into specific calibration issues

SCIAMACHY Level 1 data: calibration concept and in-flight calibration

The calibration of SCIAMACHY was thoroughly checked since the instrument was launched on-board ENVISAT in February 2002. While SCIAMACHY's functional performance is excellent since launch, a number of technical difficulties have appeared, that required adjustments to the calibration. The problems can be separated into three types: (1) Those caused by the instrument and/or platform environment. Among these are the high water content in the satellite structure and/or MLI layer. This results in the deposition of ice on the detectors in channels 7 and 8 which seriously affects the retrievals in the IR, mostly because of the continuous change of the slit function caused by scattering of the light through the ice layer. Additionally a light leak in channel 7 severely hampers any retrieval from this channel. (2) Problems due to errors in the on-ground calibration and/or data processing affecting for example the radiometric calibration. A new approach based on a mixture of onground and in-flight data is shortly described here. (3) Problems caused by principal limitations of the calibration concept, e.g. the possible appearance of spectral structures after the polarisation correction due to unavoidable errors in the determination of atmospheric polarisation. In this paper we give a complete overview of the calibration and problems that still have to be solved. We will also give an indication of the effect of calibration problems on retrievals where possible. Since the operational processing chain is currently being updated and no newly processed data are available at this point in time, for some calibration issues only a rough estimate of the effect on Level 2 products can be given. However, it is the intention of this paper to serve as a future reference for detailed studies into specific calibration issues