LOFAR low-band antenna observations of the 3C295 and Bootes fields: source counts and ultra-steep spectrum sources

We present LOFAR Low Band observations of the Bootes and 3C295 fields. Our images made at 34, 46, and 62 MHz reach noise levels of 12, 8, and 5 mJy beam−1, making them the deepest images ever obtained in this frequency range. In total, we detect between 300 and 400 sources in each of these images, covering an area of 17 to 52 deg 2. From the observations we derive Euclidean-normalized differential source counts. The 62 MHz source counts agree with previous GMRT 153 MHz and VLA 74 MHz differential source counts, scaling with a spectral index of −0.7. We find that a spectral index scaling of −0.5 is required to match up the LOFAR 34 MHz source counts. This result is also in agreement with source counts from the 38 MHz 8C survey, indicating that the average spectral index of radio sources flattens towards lower frequencies. We also find evidence for spectral flattening using the individual flux measurements of sources between 34 and 1400 MHz and by calculating the spectral index averaged over the source population. To select ultra-steep spectrum (α<−1.1 ) radio sources, that could be associated with massive high redshift radio galaxies, we compute spectral indices between 62 MHz, 153 MHz and 1.4 GHz for sources in the Booötes field. We cross-correlate these radio sources with optical and infrared catalogues and fit the spectral energy distribution to obtain photometric redshifts. We find that most of these ultra-steep spectrum sources are located in the 0.7≲z≲2.5 range

Zoetwatervoorziening in Nederland : landelijke analyse knelpunten in de 21e eeuw

Deze knelpuntenanalyse is een eerste stap in een verkenning van de zoetwaterproblematiek. Doel van de landelijke knelpuntenanalyse is om vast te stellen waar de toekomstige watervraag groter is dan de waterbeschikbaarheid, hetzij qua hoeveelheid, hetzij qua kwaliteit. Daartoe is de watervraag van diverse gebruikers in beeld gebracht, evenals de waterbeschikbaarheid, nu en in de toekomst. Voor het verkennen van de toekomst is gebruik gemaakt van deltascenario's

Development and evaluation of an interface for coupled capillary supercritical-fluid chromatography / magnetic sector mass spectrometry : application to thermally instable and high molecular mass compounds

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Development and evaluation of an interface for coupled capillary supercritical fluid chromatography/magnetic sector mass spectrometry : application to thermally unstable and high molecular mass compounds

An interface for coupling supercritical fluid chromatography to a magnetic sector mass spectrometer was developed and evaluated. The interface is based on direct introduction of the mobile phase, carbon dioxide, into the ion-source of the mass spectrometer. The SFC-MS system was optimized with respect to the signal-to-noise ratio. Under optimized conditions, the estimated detection limit for n-pentadecane is approximately 30 ppm. Spectra obtained in the electron-impact ionization mode show a very good similarity with library spectra. The performance of the SFC-MS system was evaluated by the analysis of a number of test mixtures. A sample containing several low molecular mass, thermally unstable compounds, which could neither be analyzed by GC-MS nor by LC-MS, was analyzed. Also for the analysis of high molecular mass compounds, the coupled system showed a good performance

Modeling buprenorphine reduction of fentanyl-induced respiratory depression

BACKGROUND. Potent synthetic opioids, such as fentanyl, are increasingly abused, resulting in unprecedented numbers of fatalities from respiratory depression. Treatment with the high-affinity mu-opioid receptor partial agonist buprenorphine may prevent fatalities by reducing binding of potent opioids to the opioid receptor, limiting respiratory depression. METHODS. To characterize buprenorphine-fentanyl interaction at the level of the mu-opioid receptor in 2 populations (opioid-naive individuals and individuals who chronically use high-dose opioids), the effects of escalating i.v. fentanyl doses with range 0.075???0.35 mg/70 kg (opioid naive) and 0.25???0.70 mg/70 kg (chronic opioid use) on iso-hypercapnic ventilation at 2???3 background doses of buprenorphine (target plasma concentrations range: 0.2???5 ng/mL) were quantified using receptor association/dissociation models combined with biophase distribution models. RESULTS. Buprenorphine produced mild respiratory depression, while high doses of fentanyl caused pronounced respiratory depression and apnea in both populations. When combined with fentanyl, buprenorphine produced a receptor binding???dependent reduction of fentanyl-induced respiratory depression in both populations. In individuals with chronic opioid use, at buprenorphine plasma concentrations of 2 ng/mL or higher, a protective effect against high-dose fentanyl was observed. CONCLUSION. Overall, the results indicate that when buprenorphine mu-opioid receptor occupancy is sufficiently high, fentanyl is unable to activate the mu-opioid receptor and consequently will not cause further respiratory depression in addition to the mild respiratory effects of buprenorphine. TRIAL REGISTRATION. Trialregister.nl, no. NL7028 (https://www.trialregister.nl/trial/7028) FUNDING. Indivior Inc., North Chesterfield, Virginia, USA