We present the calibration of the Swift Ultraviolet and Optical Telescope (UVOT ) grisms, of which there are two, providing low-resolution field spectroscopy in the ultraviolet and optical bands, ...respectively. The UV grism covers the range λ1700–5000 Å with a spectral resolution (λ/Δλ) of 75 at λ2600 Å for source magnitudes of u=10–16 mag, while the visible grism covers the range λ2850–6600 Å with a spectral resolution of 100 at λ4000 Å for source magnitudes of b=12–17 mag. This calibration extends over all detector positions, for all modes used during operations. The wavelength accuracy (1σ) is 9 Å in the UV grism clocked mode, 17 Å in the UV grism nominal mode and 22 Å in the visible grism. The range below λ2740 Å in the UV grism and λ5200 Å in the visible grism never suffers from overlapping by higher spectral orders. The flux calibration of the grisms includes a correction we developed for coincidence loss in the detector. The error in the coincidence loss correction is less than 20 per cent. The position of the spectrum on the detector only affects the effective area (sensitivity) by a few per cent in the nominal modes, but varies substantially in the clocked modes. The error in the effective area is from 9 per cent in the UV grism clocked mode to 15 per cent in the visible grism clocked mode.
We present the earliest ultraviolet (UV) spectrum of a gamma-ray burst (GRB) as observed with the Swift Ultra-Violet/Optical Telescope (UVOT). The GRB 081203A spectrum was observed for 50 s with the ...UV-grism starting 251 s after the Swift-Burst-Alert-Telescope (BAT) trigger. During this time, the GRB was ≈13.4 mag (u filter) and was still rising to its peak optical brightness. In the UV-grism spectrum, we find a damped Lyα line, Lyβ and the Lyman continuum break at a redshift z= 2.05 ± 0.01. A model fit to the Lyman absorption implies a gas column density of log NH i= 22.0 ± 0.1 cm−2, which is typical of GRB host galaxies with damped Lyα absorbers. This observation of GRB 081203A demonstrates that for brighter GRBs (v≈ 14 mag) with moderate redshift (0.5 < z < 3.5) the UVOT is able to provide redshifts, and probe for damped Lyα absorbers within 4–6 min from the time of the Swift-BAT trigger.
We investigated the process of recovery from anorexia nervosa using grounded theory. Open-ended interviews conducted with 9 women who had recovered from anorexia nervosa revealed that recovery ...focused on rediscovery and redefinition of the self and included the following: (1) seeing the dangers, (2) inching out of anorexia, (3) tolerating exposure without anorexia, (4) gaining perspective by changing the anorexia mindset, and (5) discovering and reclaiming self as "good enough." The process of recovery described in this study may provide a useful framework for helping women understand their own process of recovery, and introducing them to strategies that support their recovery efforts. The findings also support therapies that foster therapeutic alliance, acknowledge readiness for change, and promote a sense of autonomy.
Objective. To compare organ specific radiation dose and image quality in kidney stone patients scanned with standard CT reconstructed with filtered back projection (FBP-CT) to those scanned with low ...dose CT reconstructed with iterative techniques (IR-CT). Materials and Methods. Over a one-year study period, adult kidney stone patients were retrospectively netted to capture the use of noncontrasted, stone protocol CT in one of six institutional scanners (four FBP and two IR). To limit potential CT-unit use bias, scans were included only from days when all six scanners were functioning. Organ dose was calculated using volumetric CT dose index and patient effective body diameter through validated conversion equations derived from previous cadaveric, dosimetry studies. Board-certified radiologists, blinded to CT algorithm type, assessed stone characteristics, study noise, and image quality of both techniques. Results. FBP-CT (n=250) and IR-CT (n=90) groups were similar in regard to gender, race, body mass index (mean BMI = 30.3), and stone burden detected (mean size 5.4 ± 1.2 mm). Mean organ-specific dose (OSD) was 54-62% lower across all organs for IR-CT compared to FBP-CT with particularly reduced doses (up to 4.6-fold) noted in patients with normal BMI range. No differences were noted in radiological assessment of image quality or noise between the cohorts, and intrarater agreement was highly correlated for noise (AC2=0.873) and quality (AC2=0.874) between blinded radiologists. Conclusions. Image quality and stone burden assessment were maintained between standard FBP and low dose IR groups, but IR-CT decreased mean OSD by 50%. Both urologists and radiologists should advocate for low dose CT, utilizing reconstructive protocols like IR, to reduce radiation exposure in their stone formers who undergo multiple CTs.
1. 14C-Sulphamethazine (4-amino-N-(4,6-dimethyl-2-pyrimidinyl)benzene-U-14C-sulphonamide; 220 mg/kg of body weight) was given orally or i.v. to lactating dairy cows. Milk collected from 0-48 h after ...dosing accounted for 2.0% (oral dose) and 1.1% (i.v. dose) of the total 14C-activity administered. 2. Sulphamethazine accounted for 70-79% (oral dose) and 54-75% (i.v. dose) of the total 14C in milk samples collected from 0-48 h after dosing. N4-acetylsulphamethazine accounted for 1-2% (oral dose) and 1-4% (i.v. dose) of the 14C in milk. 3. The major 14C-labelled metabolite in the milk was isolated and identified as the N4-lactose conjugate of sulphamethazine, a unique type of metabolite not previously reported. This metabolite accounted for 10-14% (oral dose) and 9-20% (i.v. dose) of the 14C-activity in the milk collected from 0-48 h after dosing with 14C-sulphamethazine. 4. N4-lactose conjugates of sulphapyridine, sulphamerazine, sulphathiazole, sulphadimethoxine and sulphaquinoxaline were present in the milk from cows orally dosed with these five sulphonamide drugs.
Methoxychlor metabolism in goats [Insecticides] Davison, K L; Feil, V J; Lamoureux, C H
Journal of agricultural and food chemistry,
1982, 1982 Jan-Feb, Letnik:
30, Številka:
1
Journal Article
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