840 research outputs found
Analysis of rotational coupling in collisions of Li+ with Ne leading to double excitation of Ne \ud
Electron angular distributions due to autoionization of Ne, doubly excited to the (2p43s2)1D state in collisions with Li+ in the energy range 1.2-2.2 keV, are measured in coincidence with Li+ scattered into a well defined direction ( Phi =0 degrees , Theta cm=10.8 degrees ). The experimental findings are analysed with the help of a collision model proposed earlier. In this model the initial excitation occurs by radial diabatic coupling to a molecular Sigma -state at small distances, followed by rotational coupling to Pi - and Delta -states at intermediate distances in the second half of the collision. The energy splitting between the Sigma -, Pi - and Delta -states is described by a model function. By adapting two parameters of this model function, the experimental findings can be reproduced within the experimental error in numerical calculations involving the relevant set of coupled differential equations. \u
The performance of the EU-Rotate_N model in predicting the growth and nitrogen uptake of rotations of field vegetable crops in a Mediterranean environment
The EU-Rotate_N model was developed as a tool to estimate the growth and nitrogen (N) uptake of vegetable crop rotations across a wide range of European climatic conditions and to assess the economic and environmental consequences of alternative management strategies. The model has been evaluated under field conditions in Germany and Norway and under greenhouse conditions in China. The present work evaluated the model using Italian data to evaluate its performance in a warm and dry environment. Data were collected from four 2-year field rotations, which included lettuce (Lactuca sativa L.), fennel (Foeniculum vulgare Mill.), spinach (Spinacia oleracea L.), broccoli (Brassica oleracea L. var. italica Plenck) and white cabbage (B. oleracea convar. capitata var. alba L.); each rotation used three different rates of N fertilizer (average recommended N1, assumed farmer's practice N2=N1+0·3×N1 and a zero control N0). Although the model was not calibrated prior to running the simulations, results for above-ground dry matter biomass, crop residue biomass, crop N concentration and crop N uptake were promising. However, soil mineral N predictions to 0·6 m depth were poor. The main problem with the prediction of the test variables was the poor ability to capture N mineralization in some autumn periods and an inappropriate parameterization of fennel. In conclusion, the model performed well, giving results comparable with other bio-physical process simulation models, but for more complex crop rotations. The model has the potential for application in Mediterranean environments for field vegetable production
Regulation of microbial carbon, nitrogen, and phosphorus transformations by temperature and moisture during decomposition of Calluna vulgaris litter
New distal marker closely linked to the fragile X locus
We have isolated II-10, a new X-chromosomal probe that identifies a highly informative two-allele TaqI restriction fragment length polymorphism at locus DXS466. Using somatic cell hybrids containing distinct portions of the long arm of the X chromosome, we could localize DXS466 between DXS296 and DXS304, both of which are closely linked distal markers for fragile X. This regional localization was supported by the analysis, in fragile X families, of recombination events between these three loci, the fragile X locus and locus DXS52, the latter being located at a more distal position. DXS466 is closely linked to the fragile X locus with a peak lod score of 7.79 at a recombination fraction of 0.02. Heterozygosity of DXS466 is approximately 50%. Its close proximity and relatively high informativity make DXS466 a valuable new diagnostic DNA marker for fragile X
Thoracic and Lumbar Vertebral Bone Mineral Density Changes in a Natural Occurring Dog Model of Diffuse Idiopathic Skeletal Hyperostosis
Ankylosing spinal disorders can be associated with alterations in vertebral bone mineral density (BMD). There is however controversy about vertebral BMD in patients wuse idiopathic skeletal hyperostosis (DISH). DISH in Boxer dogs has been considered a natural occurring disease model for DISH in people. The purpose of this study was to compare vertebral BMD between Boxers with and without DISH. Fifty-nine Boxers with (n=30) or without (n=29) DISH that underwent computed tomography were included. Vertebral BMD was calculated for each thoracic and lumbar vertebra by using an earlier reported and validated protocol. For each vertebral body, a region of interest was drawn on the axial computed tomographic images at three separate locations: immediately inferior to the superior end plate, in the middle of the vertebral body, and superior to the inferior end plate. Values from the three axial slices were averaged to give a mean Hounsfield Unit value for each vertebral body. Univariate statistical analysis was performed to identify factors to be included in a multivariate model. The multivariate model including all dogs demonstrated that vertebral DISH status (Coefficient 24.63; 95% CI 16.07 to 33.19; p <0.001), lumbar vertebrae (Coefficient -17.25; 95% CI -23.42 to -11.09; p < 0.01), and to a lesser extent higher age (Coefficient -0.56; 95% CI -1.07 to -0.05; p = 0.03) were significant predictors for vertebral BMD. When the multivariate model was repeated using only dogs with DISH, vertebral DISH status (Coefficient 20.67; 95% CI, 10.98 to 30.37; p < 0.001) and lumbar anatomical region (Coefficient -38.24; 95% CI, -47.75 to -28.73; p < 0.001) were again predictors for vertebral BMD but age was not. The results of this study indicate that DISH can be associated with decreased vertebral BMD. Further studies are necessary to evaluate the clinical importance and pathophysiology of this finding
Mixed configuration-interaction and many-body perturbation theory calculations of energies and oscillator strengths of J=1 odd states of neon
Ab-initio theory is developed for energies of J=1 particle-hole states of
neutral neon and for oscillator strengths of transitions from such states to
the J=0 ground state. Hole energies of low-Z neonlike ions are evaluated.Comment: 5 pages, 1 figure, 4 table
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Impact of meal fatty acid composition on postprandial lipaemia, vascular function and blood pressure in postmenopausal women
Cardiovascular diseases (CVD) are the leading cause of death in women globally, with aging associated with progressive endothelial dysfunction and increased CVD risk. Natural menopause is characterised by raised non-fasting triacylglycerol (TAG) concentrations and impairment of vascular function compared with premenopausal women. However, the mechanisms underlying the increased CVD risk after women have transitioned through the menopause are unclear. Dietary fat is an important modifiable risk factor relating to both postprandial lipaemia and vascular reactivity. Meals rich in saturated (SFA) and monounsaturated fatty acids (MUFA) are often associated with greater postprandial TAG responses compared with those containing n-6 polyunsaturated fatty acids (PUFA), but studies comparing their effects on vascular function during the postprandial phase are limited, particularly in postmenopausal women. This review aimed to evaluate the acute effects of test meals rich in SFA, MUFA and n-6 PUFA on postprandial lipaemia, vascular reactivity and other CVD risk factors in postmenopausal women. The systematic literature search identified 778 publications. The impact of fat-rich meals on postprandial lipaemia was reported in seven relevant studies, of which meal fat composition was compared in one study described by three papers. An additional study determined the impact of a high fat meal on vascular reactivity. Although moderately consistent evidence suggests detrimental effects of high fat meals on postprandial lipaemia in postmenopausal (than premenopausal) women, there is insufficient evidence to establish the impact of meals of differing fat composition. Furthermore, there is no robust evidence to conclude the effect of meal fatty acids on vascular function or blood pressure. In conclusion, there is an urgent requirement for suitably powered robust randomised controlled trials to investigate the impact of meal fat composition on postprandial novel and established CVD risk markers in postmenopausal women, an understudied population at increased cardiometabolic risk
Isotope shift in the electron affinity of chlorine
The specific mass shift in the electron affinity between ^{35}Cl and ^{37}Cl
has been determined by tunable laser photodetachment spectroscopy to be
-0.51(14) GHz. The isotope shift was observed as a difference in the onset of
the photodetachment process for the two isotopes. In addition, the electron
affinity of Cl was found to be 29138.59(22) cm^{-1}, giving a factor of 2
improvement in the accuracy over earlier measurements. Many-body calculations
including lowest-order correlation effects demonstrates the sensitivity of the
specific mass shift and show that the inclusion of higher-order correlation
effects would be necessary for a quantitative description.Comment: 16 pages, 6 figures, LaTeX2e, amsmat
A Probabilistic Multimedia Retrieval Model and its Evaluation
We present a probabilistic model for the retrieval of multimodal documents. The model is based on Bayesian decision theory and combines models for text-based search with models for visual search. The textual model is based on the language modelling approach to text retrieval, and the visual information is modelled as a mixture of Gaussian densities. Both models have proved successful on various standard retrieval tasks. We evaluate the multimodal model on the search task of TREC′s video track. We found that the disclosure of video material based on visual information only is still too difficult. Even with purely visual information needs, text-based retrieval still outperforms visual approaches. The probabilistic model is useful for text, visual, and multimedia retrieval. Unfortunately, simplifying assumptions that reduce its computational complexity degrade retrieval effectiveness. Regarding the question whether the model can effectively combine information from different modalities, we conclude that whenever both modalities yield reasonable scores, a combined run outperforms the individual runs
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