| 1. |
- Lambert, A., et al.
(författare)
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Validation of the Aura Microwave Limb Sounder middle atmosphere water vapor and nitrous oxide measurements
- 2007
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 112:D24
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Tidskriftsartikel (refereegranskat)abstract
- The quality of the version 2.2 (v2.2) middle atmosphere water vapor and nitrous oxide measurements from the Microwave Limb Sounder (MLS) on the Earth Observing System (EOS) Aura satellite is assessed. The impacts of the various sources of systematic error are estimated by a comprehensive set of retrieval simulations. Comparisons with correlative data sets from ground-based, balloon and satellite platforms operating in the UV/ visible, infrared and microwave regions of the spectrum are performed. Precision estimates are also validated, and recommendations are given on the data usage. The v2.2 H 2 O data have been improved over v1.5 by providing higher vertical resolution in the lower stratosphere and better precision above the stratopause. The single-profile precision is ∼0.2-0.3 ppmv (4-9%), and the vertical resolution is ∼3-4 km in the stratosphere. The precision and vertical resolution become worse with increasing height above the stratopause. Over the pressure range 0.1-0.01 hPa the precision degrades from 0.4 to 1.1 ppmv (6-34%), and the vertical resolution degrades to ∼12-16 km. The accuracy is estimated to be 0.2-0.5 ppmv (4-11%) for the pressure range 68-0.01 hPa. The scientifically useful range of the H 2 O data is from 316 to 0.002 hPa, although only the 82-0.002 hPa pressure range is validated here. Substantial improvement has been achieved in the v2.2 N 2 O data over v1.5 by reducing a significant low bias in the stratosphere and eliminating unrealistically high biased mixing ratios in the polar regions. The single-profile precision is ∼13-25 ppbv (7-38%), the vertical resolution is ∼4-6 km and the accuracy is estimated to be 3-70 ppbv (9-25%) for the pressure range 100-4.6 hPa. The scientifically useful range of the N 2 O data is from 100 to 1 hPa. Copyright 2007 by the American Geophysical Union.
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| 2. |
- Santee, M.L., et al.
(författare)
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Validation of the Aura Microwave Limb Sounder HNO3 Measurements
- 2007
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 112:D24
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Tidskriftsartikel (refereegranskat)abstract
- [1] We assess the quality of the version 2.2 (v2.2) HNO(3) measurements from the Microwave Limb Sounder (MLS) on the Earth Observing System Aura satellite. The MLS HNO(3) product has been greatly improved over that in the previous version (v1.5), with smoother profiles, much more realistic behavior at the lowest retrieval levels, and correction of a high bias caused by an error in one of the spectroscopy files used in v1.5 processing. The v2.2 HNO(3) data are scientifically useful over the range 215 to 3.2 hPa, with single-profile precision of similar to 0.7 ppbv throughout. Vertical resolution is 3-4 km in the upper troposphere and lower stratosphere, degrading to similar to 5 km in the middle and upper stratosphere. The impact of various sources of systematic uncertainty has been quantified through a comprehensive set of retrieval simulations. In aggregate, systematic uncertainties are estimated to induce in the v2.2 HNO(3) measurements biases that vary with altitude between +/- 0.5 and +/- 2 ppbv and multiplicative errors of +/- 5-15% throughout the stratosphere, rising to similar to +/- 30% at 215 hPa. Consistent with this uncertainty analysis, comparisons with correlative data sets show that relative to HNO(3) measurements from ground- based, balloon- borne, and satellite instruments operating in both the infrared and microwave regions of the spectrum, MLS v2.2 HNO(3) mixing ratios are uniformly low by 10-30% throughout most of the stratosphere. Comparisons with in situ measurements made from the DC-8 and WB-57 aircraft in the upper troposphere and lowermost stratosphere indicate that the MLS HNO(3) values are low in this region as well, but are useful for scientific studies (with appropriate averaging).
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| 3. |
- Blevins, J. E., et al.
(författare)
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Normal feeding and body weight in Fischer 344 rats lacking the cholecystokinin-1 receptor gene
- 2009
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Ingår i: Brain Research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1255, s. 98-112
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Tidskriftsartikel (refereegranskat)abstract
- A large body of evidence has demonstrated that one mechanism by which cholecystokinin (CCK) inhibits food intake through activation of CCK1 receptors (CCK1R) on vagal afferent neurons that innervate the gastrointestinal tract and project to the hindbrain. OLETF rats, which carry a spontaneous null mutation of the CCK1R, are hyperphagic, obese, and predisposed to type 2 diabetes. Recently, by introgressing the OLETF-derived, CCK1R-null gene onto a Fischer 344 genetic background, we have been able to generate a CCK1R-deficient, congenic rat strain, F344.Cck1r(-/-), that in contrast to OLETF rats, possesses a lean and normoglycemic phenotype. In the present study, the behavioral and neurobiological phenotype of this rat strain was characterized more fully. As expected, intraperitoneal injections of CCK-8 inhibited intake of chow and Ensure Plus and induced Fos responses in the area postrema and the gelatinosus, commissural and medial subdivisions of the nucleus tractus solitarius of wild-type F344.Cck1r(-/-) rats, whereas CCK-8 was without effect on food intake or Fos induction in the F344.Cck1r(-/-) rats. F344.Cck1r(-/-) and F344.Cck1r(-/-) rats did not differ in body weight and showed comparable weight gain when maintained on Ensure Plus for 2 weeks. Also, no difference was found in 24-h food intake, and dark-phase meal frequency or meal size between F344.Cck1r(-/-) and F344.Cck1r(-/-) rats. As expected, blockade of endogenous CCK action at CCK1R increased food intake and blocked the effects of peripheral CCK-8 in wild-type F344.Cck1r(+/+) rats. These results confirm that in rats with a F344 background, CCK-1R mediates CCK-8-induced inhibition of food intake and Fos activation in the hindbrain and demonstrate that selective genetic ablation of CCK1R is not associated with altered meal patterns, hyperphagia, or excessive weight gain on a palatable diet. Published by Elsevier B.V.
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| 4. |
- Green, J. A., et al.
(författare)
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The 6-GHz multibeam maser survey-I. Techniques
- 2009
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 392:2, s. 783-794
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Tidskriftsartikel (refereegranskat)
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| 5. |
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| 6. |
- Skovsted, Christian B., et al.
(författare)
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Early Cambrian record of failed durophagy and shell repair in an epibenthic mollusc
- 2007
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 3:3, s. 314-317
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Tidskriftsartikel (refereegranskat)abstract
- Predation is arguably one of the main driving forces of early metazoan evolution, yet the fossil record of predation during the Ediacaran–Early Cambrian transition is relatively poor. Here, we present direct evidence of failed durophagous (shell-breaking) predation and subsequent shell repair in the Early Cambrian (Botoman) epibenthic mollusc Marocella from the Mernmerna Formation and Oraparinna Shale in the Flinders Ranges, South Australia. This record pushes back the first appearance of durophagy on molluscs by approximately 40 Myr.
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| 7. |
- Thorup, K, et al.
(författare)
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Do migratory flight paths of raptors follow constant geographical or geomagnetic courses?
- 2006
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Ingår i: Animal Behaviour. - : Elsevier BV. - 1095-8282 .- 0003-3472. ; 72:4, s. 875-880
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Tidskriftsartikel (refereegranskat)abstract
- We tested whether routes of raptors migrating over areas with homogeneous topography follow constant geomagnetic courses more or less closely than constant geographical courses. We analysed the routes taken over land of 45 individual raptors tracked by satellite-based radiotelemetry: 25 peregrine falcons, Falco peregrinus, on autumn migration between North and South America, and seven honey buzzards, Pernis apivorus, and 13 ospreys, Pandion haliaetus, on autumn migration between Europe and Africa. Overall, migration directions showed a better agreement with constant geographical than constant geomagnetic courses. Tracks deviated significantly from constant geomagnetic courses, but were not significantly different from geographical courses. After we removed movements directed far from the mean direction, which may not be migratory movements, migration directions still showed a better agreement with constant geographical than constant geomagnetic courses, but the directions of honey buzzards and ospreys were not significantly different from constant geomagnetic courses either. That migration routes of raptors followed by satellite telemetry are in closer accordance with constant geographical compass courses than with constant geomagnetic compass courses may indicate that geographical (e.g. based on celestial cues) rather than magnetic compass mechanisms are of dominating importance for the birds' long-distance orientation. Published by Elsevier Ltd on behalf of The Association for the Study or Animal Behaviour.
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| 8. |
- Åkesson, Lina, et al.
(författare)
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Increased Lipid Oxidation Heralds Diabetes Onset in DR.lyp/lyp Rats.
- 2008
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Ingår i: Experimental and Clinical Endocrinology & Diabetes. - : Georg Thieme Verlag KG. - 1439-3646 .- 0947-7349. ; 116, s. 475-480
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Tidskriftsartikel (refereegranskat)abstract
- AIM: The BB rat model of type 1 diabetes exhibits altered body weight gain and body temperature regulation prior to hyperglycemia onset, implying the existence of as yet unidentified biomarkers of autoimmune processes that destroy pancreatic beta cells. To investigate this hypothesis, we compared the metabolic profile of diabetes-resistant DR.lyp/+ rats and their diabetes-prone, congenic DR.lyp/lyp littermates in the days leading up to diabetes onset. METHODS: Except for the Gimap5 mutation on chromosome 4, congenic DR.lyp/lyp rats are genetically identical to DR.lyp/+ littermates. They invariably develop hyperglycemia at 46-81 days of age, whereas DR.lyp/+ rats do not develop diabetes. In addition to daily food intake and body weight, indirect calorimetry was performed continuously on male DR.lyp/lyp and DR.lyp/+ rats (n=6/group) for 6-18 days to measure locomotor activity, VO (2), VCO (2) and RQ. RESULTS: DR.lyp/lyp rats exhibited a progressive decrease of RQ compared to DR.lyp/+ rats 0.005+/-0.001 units/day (p<0.005). Limiting the analysis to the six days prior to diabetes onset revealed a larger decrease of 0.007+/-0.002 units/day (p<0.001) in DR.lyp/lyp animals, whereas RQ of the DR.lyp/+ rats remained unchanged. This metabolic change occurred prior to hyperglycemia onset and was not associated with changes of any other parameter. CONCLUSIONS: Diabetes onset in DR.lyp/lyp rats is heralded by a progressive shift towards lipid oxidation relative to carbohydrate metabolism.
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