Low-cost modifications of the traditional Ethiopian tine plough for land shaping and surface drainage of heavy clay soils: Preliminary results from on-farm verification trials

Describes modifications to the traditional ox-drawn ard plow (maresha) for use in the construction of terraces for soil conservation and of raised beds and furrows to facilitate drainage on heavy clay soils together with results of on-station and on-farm tests. Both modifications can be made by village craftsmen

Common mechanisms in intelligence and development: a study of ability profiles in mental age-matched primary school children

BACKGROUND AND AIMS: We examine the relationship between individual differences and cognitive development in order to address the question of whether variability in each might be due to common mechanisms. In two experiments, we compare the cognitive profiles of groups of younger and older children matched on overall mental age (MA) using standard tests of intelligence (British Abilities Scales-II; BAS-II, and Wechsler Intelligence Scale for Children, 3rd edition; WISC-III). RESULTS: In both experiments, MANOVAs revealed few differences in the profiles of younger and older MA-matched children. In Experiment 1, no reliable differences were found on the six BAS-II core scales, and only one group difference was found on the supplementary, Speed of Processing diagnostic test, where the older children outperformed the younger children. In Experiment 2, analyses of the 10 core scales of the WISC-III revealed two group differences. These were on Coding, where the younger children's performance was superior to the older children, and on Arithmetic, where the older children outperformed the younger children. CONCLUSIONS: The degree of similarity between cognitive profiles of younger and older MA-matched groups suggests that a common mechanism may indeed underlie variability in individual differences and development. The findings further suggest that children of different ages, who are of the same overall ability level, are at the same developmental and intellectual level. However, further research is needed to determine just how similar ability-matched children remain over the course of development

Deformation of the Planetary Orbits Caused by the Time Dependent Gravitational Potential in the Universe

In the paper are studied the deformations of the planetary orbits caused by the time dependent gravitational potential in the universe. It is shown that the orbits are not axially symmetric and the time dependent potential does not cause perihelion precession. It is found a simple formula for the change of the orbit period caused by the time dependent gravitational potential and it is tested for two binary pulsars.Comment: 7 page

Evaluation of Percent Cover Requirements for Revegetation of Disturbed Sites on Alaska's North Slope

On the North Slope of Alaska, attempts have been made to revegetate areas damaged by development. Some revegetation projects strive to achieve specific performance standards based on percent vegetation cover. This study uses data collected from 60 sites over 16 years to compare revegetating sites and natural reference sites. Results demonstrate that percent cover in most revegetation settings has the potential to reach levels comparable to those of reference sites, depending on how cover is defined. Linear models that explain between 48% and 84% of the variability in data show that planting cultivar seeds and fertilizing can increase cover (p < 0.05 for all models) and that cover continues to increase over time (p < 0.05 for all models), provided that cover is defined to include all live plants and plant litter. Ordination analysis separates reference sites from most revegetating sites along two significant axes (Monte Carlo tests, p < 0.01 with 100 randomizations). Comparison of ordination results with plots of change in plant cover over time shows that plant cover offers only limited insight into plant community development. If percent cover is to be used as a performance standard, it should be clearly defined, and the link between percent cover and restoration objectives should be carefully considered. Although this paper focuses on North Slope revegetation projects, the issues that are addressed have implications for all projects with performance standards calling for specific percent cover by vegetation.Le versant Nord de l'Alaska a fait l'objet de tentatives de reverdissement dans des zones endommagées par l'exploitation. Certains projets de remise en état s'efforcent d'atteindre des normes de rendement spécifiques qui s'appuient sur le pourcentage de tapis végétal. Cette étude fait appel aux données collectées à 60 emplacements sur une durée de 16 ans afin de comparer les sites de reverdissement avec des sites témoins laissés à l'état naturel. Les résultats montrent qu'à la plupart des endroits de reverdissement, le pourcentage de tapis végétal a le potentiel d'atteindre des niveaux comparables à ceux des sites témoins, selon la définition du tapis végétal. Les modèles linéaires, qui expliquent entre 48 et 84 % de la variabilité dans les données, montrent que le fait de planter des semences de cultivars et de mettre de l'engrais peut accroître le tapis (p < 0,05 pour tous les modèles) et que ce dernier continue d'augmenter au fil du temps (p < 0,05 pour tous les modèles), à condition d'inclure toutes les plantes vivantes et la litière végétale dans la définition du tapis végétal. L'analyse d'ordination permet de distinguer les sites témoins de la majorité des sites reverdis selon deux grands axes (tests de Monte Carlo, p < 0,01 avec 100 randomisations). La comparaison des résultats de l'ordination avec les courbes de changement dans la couverture végétale en fonction du temps révèle que la couverture n'offre qu'un aperçu limité de l'évolution du peuplement végétal. Si le pourcentage de tapis doit servir de norme de rendement, il faut en donner une définition précise, et examiner en détail le lien entre le pourcentage de tapis et les objectifs de restauration. Si cet article se concentre sur les projets de remise en état du versant Nord, les questions qu'il soulève ont des implications pour tous les projets où les normes de rendement prévoient un pourcentage spécifique de tapis végétal

State-selective imaging of cold atoms

Atomic coherence phenomena are usually investigated using single beam techniques without spatial resolution. Here we demonstrate state-selective imaging of cold 85Rb atoms in a three-level ladder system, where the atomic refractive index is sensitive to the quantum coherence state of the atoms. We use a phase-sensitive diffraction contrast imaging (DCI) technique which depends on the complex refractive index of the atom cloud. A semiclassical model allows us to analytically calculate the detuning-dependent refractive index of the system. The predicted Autler-Townes splitting and our experimental measurements are in excellent agreement. DCI provided a quantitative image of the distribution of the excited-state fraction, and compared with on-resonance absorption and blue cascade fluorescence techniques, was found to be experimentally simple and robust

Dental School “Research Publication Distribution” in Dental Versus Non-Dental Journals

http://deepblue.lib.umich.edu/bitstream/2027.42/101139/1/2007-IADR-Poster-Bayne.pd

Infrared studies of ortho-para conversion at Cl-atom and H-atom impurity centers in cryogenic solid hydrogen

We report infrared spectroscopic studies of H₂ ortho-para (o/p) conversion in solid hydrogen doped with Clatoms at 2 K while the Cl+H₂(v=1)→HCl+H infrared-induced chemical reaction is occurring. The Cl-atom doped hydrogen crystals are synthesized using 355 nm in situ photodissociation of Cl₂ precursor molecules. For hydrogen solids with high ortho-H₂ fractional concentrations (Xo=0.55), the o/p conversion kinetics is dominated by Cl-atom catalyzed conversion with a catalyzed conversion rate constant Kcc=1.16(11) min⁻¹ and the process is rate-limited by ortho-H₂ quantum diffusion. For hydrogen crystals with low ortho-H₂ concentrations (Xo=0.03), single-exponential decay of the ortho-H₂ concentration with time is observed which is attributed to H-atom catalyzed o/p conversion by the H-atoms produced during the infrared-induced Cl+H₂ reaction. The measured H-atom catalyzed o/p conversion kinetics indicates the H-atoms are mobile under these conditions in agreement with previous ESR measurements

Underlying Pairing States in Cuprate Superconductors

In this Letter, we develop a microscopic theory to describe the close proximity between the insulating antiferromagnetic (AF) order and the d-wave superconducting (dSC) order in cuprates. We show that the cuprate ground states form a configuration of coherent pairing states consisting of extended singlet Cooper pairs and triplet $\pi$ pairs, which can simultaneously describe AF and dSC orders.Comment: 4 papes, 1 figur