bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison between radiosonde, rocketsonde, and satellite observations of atmospheric temperatures
Authors: Barnett J. J. , Harwood R. S. , Houghton J. T. , Morgan C. G. , Rodgers C. D. , Williamson E. J. 
Published: February 2007

AbstractComparisons have been made between satellite measured radiances and those derived from radiosonde/rocketsonde profiles for several samples for both the Nimbus 4 and Nimbus 5 selective chopper radiometers during the period 1970–1973. Agreement between satellite and radiosonde measurements in the upper troposphere and lower stratosphere is better than 1 K in equivalent temperature. For rocketsonde observations mean differences of up to 3 K in equivalent temperature are found but these are within the combined experimental error of the measurements. Good confidence can, therefore, be placed on the method based on laboratory measured transmissions of deriving weighting functions for the satellite instruments.
A multi‐layer spectral model and the semi‐implicit method
Authors: Hoskins B. J. , Simmons A. J. 
Published: February 2007

AbstractThe formulaton of a multi‐layer primitive equation model on the sphere is described. The horizontal representation is by means of spherical harmonics, truncated either in the triangular or rhomboidal manner. The time integration is performed using the semi‐implicit method in which the linearized gravity wave terms are time averaged and thus the fast moving waves of this type are slowed. For a 5‐layer hemispheric model with triangular truncation at wavenumber 21, storage of 38K words is needed and with the time scheme allowing a time‐step of 90 minutes, one day's simulation requires 11 seconds of CDC 7600 time. The growth of a baroclinic wave on a simple basic state of differential solid body rotation is exhibited. The errors involved in this case in utilizing the large time‐step allowed by the semi‐implicit scheme are thoroughly examined by comparing wave amplitudes and phases, conservation properties and gravity wave treatment for different time‐steps. These errors are found to be negligible. The conservation properties of the model are in fact extremely good. The vertical finite differencing scheme of Arakawa is studied in the same baroclinic instability simulation. The growth is similar though the conservation of angular momentum is greatly improved. The transform method used in all these integrations allows some aliasing, but this is shown to be negligible.
Turbulent wind flow over a low hill
Authors: Jackson P. S. , Hunt J. C. R. 
Published: February 2007

AbstractAn analytical solution is presented for the flow of an adiabatic turbulent boundary layer on a uniformly rough surface over a two‐dimensional hump with small curvature, e.g. a low hill. The theory is valid in the limit L/y0 → ∞ when h/L < 1/8(y0/L)0.1 and δ/L > 2k2/ln(δ/y0) where L and h are the characteristic length and height of the hump, y0 the roughness length of the surface and δ the thickness of the boundary layer. For rural terrain, taking δ ∼ 600m these conditions imply that 102 < L < 104m and h/L < 0·05. Considerations of the turbulent energy balance suggest that the eddy viscosity distribution for equilibrium flow near a wall may still be used to a good approximation to determine the changes in Reynolds stress. This result is only required in a thin layer adjacent to the surface ‐ in the main part of the boundary layer the perturbation stresses are shown to be negligible and the disturbance to be almost irrotational. The theory shows that for a log‐profile upwind the increase in wind speed near the surface of the hill is O((h/L)u0(L)) where u0(L) is the velocity of the incident wind at a height L. Thus the increase in surface winds can be considerably greater than is predicted by potential flow theory based on an upwind velocity u0(h). It is also found that, at the point above the top of a low hill at which the increase in velocity is a maximum, the velocity is approximately equal to the velocity at the same elevation above level ground upwind of the hill. The surface stress is highly sensitive to changes in the surface elevation, being doubled by a slope as small as one in five. The turning of the wind in the Ekman layer may induce a change in direction of the wind above the hill.The main object of this analysis is to show how the changes in wind speed and shear stress are related to the size and shape of the hill and to the roughness of the surface. Some comparisons are made with measurements of the natural wind and wind tunnel flows. These suggest that the theory may be useful in giving rough estimates of the effect of hills on the wind. The theory and the quoted measurements suggest that the present design recommendation for the increase in wind speeds over hills to be used in wind loading calculations may be an underestimate. It is to be hoped that this analysis will encourage more detailed measurements to be made of the wind over hills.
Rainfall trends in the West African Sahel
Authors: Bunting A. H. , Dennett M. D. , Elston J. , Milford J. R. 
Published: February 2007

AbstractA statistical analysis has been made of long‐term rainfall records from West Africa. No established trends or periodicities can be detected, and the recent succession of drought years falls within statistical expectation. Sahelian rainfall is not clearly linked to the frequency of westerly weather over Britain.
Baroclinic waves and frontogenesis Part I: Introduction and Eady waves
Authors: Hoskins B. J. 
Published: February 2007

AbstractThe semi‐geostrophic equations are derived from the primitive equations with the momentum approximated by its geostrophic value. Here these equations are used to study the stability of a zonal flow. The quasi‐geostrophic instability criterion is given a more accurate form. The semi‐geostrophic equations are also used for a numerical and analytical study of the development into the nonlinear regime of the Eady wave instability mode of a zonal flow with uniform shear in the vertical. The nonlinear tightening of the low pressure, the occlusion process and the formation of a warm frontal region are all evident in these solutions.
A laboratory model of diffusion into the convective planetary boundary layer
Authors: Willis G. E. , Deardorff J. W. 
Published: February 2007

AbstractA laboratory model of the convective planetary boundary layer has provided information concerning the evolution of concentration distributions downwind from a simulated continuous point source located near the ground. Results indicate that a Gaussian plume formulation adequately describes the model γ‐concentration distributions, but is useful in predicting the z‐concentration distributions only to a distance downstream of about x = 0.5zi/(w*/U), where zi is the mixed layer depth and w*/U is a dimensionless stability parameter. Near this distance an elevated concentration maximum appears at a height above the source release height. The elevated maximum rises to a height of about 0.8zi at x = 1.7zi/(w*/U) and retains its identity until the pollutants become vertically well mixed farther downstream. Use of the stability parameter w*/U permits the model results to be applied to a range of atmospheric conditions encompassing the Pasquill‐Gifford stability classes A and B. Close agreement is found between the laboratory data and the atmospheric observations of ground‐level lateral spread of Islitzer (1961) and Islitzer and Dumbauld (1963), where the latter measurements extended out to x≃ 3 km.
Infrared absorption and liquid water content in stratocumulus clouds
Authors: Platt C. M. R. 
Published: February 2007

AbstractSimultaneous measurements of narrow‐beam vertical infrared radiance (10–12μm), cloud dropsize distributions, temperature and humidity in some stratocumulus clouds are reported.Cloud volume absorption coefficients calculated from mean dropsize distributions are found to be well correlated with the cloud liquid water content. Values of cloud volume absorption coefficient are found to vary from 2 to 20 km−1 for a range in liquid water content from 0.02 to 0.27gm−3. The equivalent variation in cloud mass absorption coefficient is from 700 to 1030g−1 cm2, with a mean value for all clouds of 765g−1 cm2. From the radiance measurements the clouds are found to become ‘black’ for depths ranging from about 100 to 450m. The variation of measured cloud emissivity with liquid water mass is found to be consistent, within the observed variabilities of the clouds, with the emissivities calculated from the above mean absorption coefficient. The results are compared with earlier flux measurements.
Production of nitrogen oxides by lightning discharges
Authors: Tuck A. F. 
Published: February 2007

AbstractThe annual production of nitric oxide by lightning discharges is estimated to be 1.8 × 1035 molecules, within rather large limits of uncertainty. Implications for the global budget of odd nitrogen species are cursorily examined. More data are needed to decide whether or not lightning‐produced nitrogen oxides are transported in significant quantities to the stratosphere.Closer studies of the budget of nitrate in rainwater, and of air trajectories in large cumulonimbus storms, are also indicated.
A comparative study of radiation balance above forest and grassland
Authors: Moore C. J. 
Published: February 2007

AbstractDaily net radiation above a Pinus radiata plantation was found to exceed that measured above nearby grassland by about 12% during the winter and 24% during the summer months. This difference was related to differences in the albedo and net longwave radiation associated with the surface temperature of each vegetation. Forest albedo was found to be 0.11 ± 0.001 throughout the winter and did not exhibit a significant diurnal variation. The grassland albedo was found to give the usual diurnal trend and a mean winter albedo of 0.27 ± 0.03 which decreased to 0.24 ± 0.01 in summer, consistent with increasing solar elevation.Hourly values of net radiation Rn above the forest during daylight hours were found to exceed those for grassland by about 15% during the winter and about 25% during the summer. When the forest was wet and the change in canopy heat storage Q and ground heat flux G were small, such differences also applied to the energy (Rn—G—Q) available for evaporation. However, when the canopy was dry, values of Q during the day were sufficiently large to reduce the forest available energy to about that of the grassland. This forest canopy energy was generally lost during the night.
The propagation of modified flow downstream of a change in roughness
Authors: Jackson N. A. 
Published: February 2007

AbstractUsing published atmospheric and wind tunnel data from a variety of sources, it is established that the rate of propagation of modified flow downstream of a change in surface roughness is determined essentially by the rougher surface. For the data examined neither the ratio of the upstream to downstream roughness lengths nor the ratio of boundary layer height to roughness element height is of itself a significant parameter.Based on an empirical analogy with Kazanskii and Monin's plume propagation concept, a simple method is proposed for predicting the depth of modified flow. The predictions include an origin correction and are shown to agree satisfactorily with measurements in neutrally stratified boundary layers.
Change in intensity of typhoons which develop cloud‐plume outflow aloft
Authors: Tsui K. S. , Bell G. J. , Fung P. C. W. 
Published: February 2007

AbstractSatellite and aircraft data indicate an approximate 0–64 probability that the intensity of a typhoon will have increased during the 24 hours prior to the time when a plume of middle and high cloud streaming from the centre of the storm towards the northeast is first seen on satellite photograph.
On the application of some stochastic models to precipitation forecasting
Authors: Dyer T. G. J. 
Published: February 2007

AbstractThe equivalent of 157 rainfall records for South Africa have been subjected to various statistical modelling techniques. These include: autoregression; multiple linear and trigonometric regression; and exponential smoothing. Between them the models cover short‐ and long‐term forecasting. the trigonometric model provides a useful forecasting aid. Estimation of the parameters in this model stem from the spectra of the raw rainfall data. the models described are limited neither to rainfall nor the area of the globe from which the present data were obtained.
Influence of cover on mean column hydraulic characteristics in small pool riffle morphology streams
Authors: Smith David L. , Brannon Ernest L. 
Published: February 2007

AbstractThe field of ecohydraulics tries to link biological‐ and physical‐based processes in order to describe better the distribution of plants and animals in rivers. We tested the hypothesis that the influence of cover in pools and riffles would not be detectable using average velocity, turbulent kinetic energy and turbulent intensity, and compared these measurements to locations distant from cover. We measured water velocity fluctuations using an acoustic Doppler velocimeter. We found that turbulent intensity in the downstream direction (u′) and the transverse or cross‐stream direction (v′) were the most useful in detecting the presence of cover in pools and riffles. Differences were apparent between locations near cover in pools and riffles. Turbulent kinetic energy (k) and vertical turbulent intensity (w′) detected cover in pools but not in riffles. Average downstream velocity ($\bar u$) detected cover in riffles but not in pools. Average cross‐stream ($\bar v$) and vertical ($\bar w$) velocities did not detect any differences at all. We rejected the null hypothesis and concluded that turbulence caused by habitat features such as large rocks, wood or other channel complexities results in a statistically meaningful difference in flow characteristics in locations near cover. This finding was tempered by the fact that knowledge about how fish respond to turbulence is limited in comparison to our understanding of average velocity values. Despite the potential benefits to habitat modelling of incorporating turbulence‐based metrics, application of these findings will be challenging because turbulence modelling is difficult and current models may not be appropriate for application to rivers. Copyright © 2007 John Wiley & Sons, Ltd.
Are clonal plants more tolerant to grazing than co‐occurring non‐clonal plants in inland dunes?
Authors: Liu Hai‐Dong , Yu Fei‐Hai , He Wei‐Ming , Chu Yu , Dong Ming 
Published: February 2007

AbstractClonal traits such as clonal integration and storage functions of rhizomes or stolons may provide clonal plants with additional advantages against grazing over non‐clonal plants. Here, we hypothesize that clonal species have a larger capacity for compensatory growth than co‐occurring non‐clonal species. In inland dunes in northern China, individual plants of two rhizomatous clonal species (Bromus ircutensis and Psammochloa villosa) and two non‐clonal ones (Artemisia intramongolica and Astragalus melilotoides) were subjected to 0% (control), 50% (moderate) and 90% (heavy) shoot removal. Compared with control, heavy clipping greatly increased the relative growth rate in Bromus and Psammochloa, but decreased that in Artemisia and Astragalus. Heavy clipping affected above‐ground dry weight and the number of modules more negatively in Artemisia and Astragalus than in Bromus and Psammochloa. These results support the hypothesis and suggest that clonal species are more tolerant to grazing than co‐occurring non‐clonal species in inland dunes.
A systematic review and meta-analysis of set-shifting ability in eating disorders
Authors: ROBERTS MARION E. , TCHANTURIA KATE , STAHL DANIEL , SOUTHGATE LAURA , TREASURE JANET 
Published: February 2007

ABSTRACTBackgroundThe aim was to critically appraise and synthesize the literature relating to set-shifting ability in eating disorders. PsycINFO, Medline, and Web of Science databases were searched to December 2005. Hand searching of eating-disorder journals and relevant reference sections was also undertaken.MethodThe 15 selected studies contained both eating disorder and healthy control groups, and employed at least one of the following six neuropsychological measures of set-shifting ability; Trail Making Test (TMT), Wisconsin Card Sort Test (WCST), Brixton task, Haptic Illusion, CatBat task, or the set-shifting subset of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The outcome variable was performance on the set-shifting aspect of the task. Pooled standardized mean differences (effect sizes) were calculated.ResultsTMT, WCST, CatBat and Haptic tasks had sufficient sample sizes for meta-analysis. These four tasks yielded acceptable pooled standardized effect sizes (0·36; TMT −1·05; Haptic) with moderate variation within studies (as measured by confidence intervals). The Brixton task showed a small pooled mean difference, and displayed more variation between sample results. The effect size for CANTAB set shifting was 0·17.ConclusionProblems in set shifting as measured by a variety of neuropsychological tasks are present in people with eating disorders.
Development and quality of porcine embryos in different culture system and embryo-producing methods
Authors: Ock S-A. , Lee S-L. , Kim J-G. , Kumar B-M. , Balasubramanian S. , Choe S-Y. , Rho G-J. 
Published: February 2007

SUMMARYIn this study, the developmental ability and cellular composition of porcine IVF, parthenote and somatic cell nuclear transfer (SCNT) embryos were evaluated following differentin vitroculture systems. Group 1, embryos were cultured in NCSU-23 with 5.55 mMD-glucose (NCSU+) until day 6 on 20% O2or 5% O2(Group 2). Group 3, embryos were cultured inD-glucose-free NCSU-23 (NCSU−) with 0.17 mM Na pyruvate/2.73 mM Na lactate for 58 h and subsequently cultured in NCSU+ until day 6 (NCSU −/+) on 20% O2or 5% O2(Group 4). IVF blastocysts did not differ significantly with O2concentrations, but differed significantly with major energy source (glucose and pyruvate/lactate). In Group 3 and 4 IVF blastocysts, the total cell number and apoptosis rates were not significantly different with different O2concentrations. Blastocyst rate, total cell number and apoptosis rate in Groups 3 and 4 parthenote embryos also were not significantly different. Parthenote and SCNT, under the same culture treatment, exhibited significant differences in blastocyst and apoptosis rates (47.5 ± 16.1 vs. 24.0 ± 4.0 and 4.9 ± 9.0 vs. 22.8 ± 23.3). Apoptosis-generating rate increased in the order parthenote, IVF and then SCNT. In conclusion,in vitrodevelopment of porcine embryos was not affected by O2concentrations but was affected by major energy source. Even so, the concentration of each major energy source and the timing of its inclusion in culture could accomplish relatively high embryonic development, the apoptosis rate stressed that more work still needs to be done in developing a better defined culture system that could support SCNT embryos equivalent toin vivopreimplantation porcine embryos.
Validation of a food-frequency questionnaire for measurement of nutrient intake in a dietary intervention study
Authors: Segovia-Siapco Gina , Singh Pramil , Jaceldo-Siegl Karen , Sabaté Joan 
Published: February 2007

AbstractObjectiveTo validate a 171-item semi-quantitative food-frequency questionnaire (FFQ) for measurement of nutrient intake in an intervention trial based on walnut supplementation.Design and settingFree-living adults from Southern California were randomly assigned to either an intervention (walnut-supplemented) or a control diet. The prescribed 6-month intervention was ≥ 28 g of walnuts per day for the walnut-supplemented group and ≤ 2 g of walnuts per day for the control group. Participants provided at least six 24-hour dietary recalls and completed a self-administered FFQ.SubjectsEighty-seven adults aged 30–72 years (48 females, 39 males).ResultsOur findings from validation (by correlation with six diet recall measures) of the measurement of 32 nutrients by the FFQ are as follows. We found significant positive correlations (corrected for measurement error) between the FFQ and diet recalls for total energy (r = 0.34), total carbohydrate (r = 0.42), vegetable protein (r = 0.43), total fat (r = 0.51), polyunsaturated fat (r = 0.77), total fibre (r = 0.60), linoleic acid (r = 0.78) and α-linolenic acid (r = 0.79) – the last nutrient being an excellent nutrient biomarker of the intervention (walnut supplementation). Significant positive correlations were also found for vitamin C (r = 0.96) and certain minerals (r = 0.46–0.80 for calcium, phosphorus, magnesium, iron and potassium). Uncorrected correlations were also high (r>0.40) for retinol, β-carotene, folate and alcohol. Both diet recalls and FFQ showed a similar significant difference in α-linolenic acid content between the walnut-supplemented and control diets.ConclusionsThe FFQ demonstrated good relative validity in the estimation intake of some of the major nutrients in a dietary intervention trial and was a particularly valid estimate of an important nutrient biomarker of walnut supplementation.
The Toll‐like receptor 7/8‐ligand resiquimod (R‐848) primes human neutrophils for leukotriene B4, prostaglandin E2 and platelet‐activating factor biosynthesis
Authors: Hattermann Kim , Picard Serge , Borgeat Mathieu , Leclerc Patrick , Pouliot Marc , Borgeat Pierre 
Published: February 2007

ABSTRACTToll‐like receptors (TLR) recognize pathogen‐associated molecular patterns and play important roles in the innate immune system. While single‐stranded viral RNA is the natural ligand of TLR7/TLR8, the imidazoquinoline resiquimod (R‐848) is recognized as a potent synthetic agonist of TLR7/TLR8. We investigated the effects of TLR7/8 activation on lipid mediator production in polymorphonuclear leukocytes exposed to R‐848. Although R‐848 had minimal effects by itself, it strongly enhanced leukotriene B4 formation on subsequent stimulation by fMLP, platelet‐activating factor, and the ionophore A23187. R‐848 acted via TLR8 but not TLR7 as shown by the lack of effect of the TLR7‐specific ligand imiquimod. Priming with R‐848 also resulted in enhanced arachidonic acid release and platelet‐activating factor formation following fMLP stimulation, as well as enhanced prostaglandin E2 synthesis following the addition of arachidonic acid. Western blot analysis demonstrated that R‐848 induced the phosphorylation of the cytosolic phospholipase A2α, promoted 5‐lipoxygenase translocation and potently stimulated the expression of the type 2 cyclooxygenase. Bafilomycin A1, an inhibitor of endosomal acidification, efficiently inhibited all R‐848‐induced effects. These studies demonstrate that TLR8 signaling strongly promotes inflammatory lipid mediator biosynthesis and provide novel insights on innate immune response to viral infections.—Hattermann K., Picard, S., Borgeat, M., Leclerc, P., Pouliot, M., Borgeat P. The Toll‐like receptor 7/8‐ligand re‐siquimod (R‐848) primes human neutrophils for leuko‐triene B4, prostaglandin E2 and platelet‐activating factor biosynthesis. FASEB J. 21, 1575–1585 (2007)