849 research outputs found
A comparison of optical and radar measurements of mesospheric winds and tides
Optical measurements of mesospheric winds by Fabry‐Perot spectrometers, FPSs, at Mawson, 67.6°S 62.9°E, and Davis, 68.6°S 78.0°E, Antarctica are compared with similar measurements obtained using a spaced‐antenna MF radar at Davis. The FPSs observed the OH emission. Different analysis procedures, used to determine the mean wind, and amplitude and phase of the semidiurnal tide, have been compared. At these latitudes the diurnal tide is weak and the semi‐diurnal tide, although highly variable in amplitude, is usually the dominant periodicity. When comparing the amplitude and phase of the semidiurnal tide good agreement is obtained between measurements by the two instruments
Is "safe effective glucose control" effective and safe?
Since tight glucose control (TGC) inevitably comes with a risk of hypoglycemia, Krinsley and Preiser [1] suggest the use of a stepwise approach to glucose control, which they call “safe, effective glucose control ” (SEGC), and that targets an intermediate blood glucose level (BGL). SEGC is intended to decrease the rate of hyperglycemia while reducing the adverse effects of severe hypoglycemia. Of note, the randomized controlled trials that showed a benefit from glucose control have tested only one and the same BGL target (4.4 to 6.1 mmol/l [80 to 110 mg/dl]) [2,3]. In addition, in these trials conventional insulin treatment was administered only when the BGL was>12 mmol/L (215 mg/dl), with insulin infusion gradually decreased and stopped when the BGL fell to <10 mmol/l (180 mg/dl). Accordingly, the average morning BGL of the conventional treatmen
Replica theory for fluctuations of the activation barriers in glassy systems
We consider the problem of slow activation dynamics in glassy systems
undergoing a random first order phase transition. Using an effective potential
approach to supercooled liquids, we determine the spectrum of activation
barriers for entropic droplets. We demonstrate that fluctuations of the
configurational entropy and of the liquid glass surface tension are crucial to
achieve an understanding of the barrier fluctuations in glassy systems and thus
are ultimatively responsible for the broad spectrum of excitations and
heterogeneous dynamics in glasses. In particular we derive a relation between
the length scale for dynamic heterogeneity and the related barrier
fluctuations. Diluted entropic droplets are shown to have a Gaussian
distribution of barriers, strongly suggesting that non-Gaussian behavior
results from droplet-droplet interactions.Comment: 16 pages, 9 eps figure
Lack of evidence of a beneficial effect of azathioprine in dogs treated with prednisolone for idiopathic immune-mediated hemolytic anemia: a retrospective cohort study
<p>Abstract</p> <p>Background</p> <p>Azathioprine is used as an immunosuppressant in canine immune-mediated hemolytic anemia (IMHA), but this potentially toxic and carcinogenic drug has not been proven to be beneficial. The aim of this study was to determine the difference in outcome and survival of dogs with idiopathic IMHA treated with a protocol that included azathioprine and prednisolone versus a protocol that included prednisolone alone.</p> <p>Results</p> <p>The study included 222 dogs with a hematocrit lower than 0.30 L/L and either a positive Coombs' test or spherocytosis and no evidence of diseases that could trigger IMHA. The clinical and laboratory data at the time of diagnosis and the response to therapy and survival were compared in dogs treated according to the prednisolone and azathioprine protocol (AP protocol; n = 149) and dogs treated according to the prednisolone protocol (P protocol; n = 73). At study entry, the two groups were comparable, except that thrombocyte counts were significantly lower and clinical signs had been present significantly longer in the AP protocol group. No significant difference in survival was found between the two groups: the 1-year survival was 64% (95% CI 54 - 77%) in the P protocol group and 69% (95% CI 59-80%) in the AP protocol group, respectively.</p> <p>Conclusions</p> <p>Azathioprine would appear not to be beneficial as standard treatment for all cases of IMHA; however, a blinded, randomized clinical trial is needed to establish whether outcome is different with the two treatment protocols.</p
Spatial sampling of the thermospheric vertical wind field at auroral latitudes
Results are presented from two nights of bistatic Doppler measurements of neutral thermospheric winds using Fabry!Perot spectrometers at Mawson and Davis stations in Antarctica. A scanning Doppler imager (SDI) at Mawson and a narrow-field Fabry-Perot spectrometer (FPS) at Davis have been used to estimate the vertical wind at three locations along the great circle joining the two stations, in addition to the vertical wind routinely observed above each station. These data were obtained from observations of the 630.0 nm airglow line of atomic oxygen, at a nominal altitude of 240 km. Low!resolution all-sky images produced by the Mawson SDI have been used to relate disturbances in the measured vertical wind field to auroral activity and divergence in the horizontal wind field. Correlated vertical wind responses were observed on a range of horizontal scales from ~150 to 480 km. In general, the behavior of the vertical wind was in agreement with earlier studies, with strong upward winds observed poleward of the optical aurora and sustained, though weak, downward winds observed early in the night. The relation between vertical wind and horizontal divergence was seen to follow the general trend predicted by Burnside et al. (1981), whereby upward vertical winds were associated with positive divergence and vice versa; however, a scale height approximately 3–4 times greater than that modeled by NRLMSISE-00 was required to best fit the data using this relation
- …