2,478 research outputs found
Electrodic processes of derivatives of 2,2,4,4-tetramethylpentane on stationary solid electrodes 1. : Cyclic voltammetry of 3-hydrazones of 2,2,4,4 - tetramethylpentane
Electrodic processes of 2,2,4,4-tetramethylpentane derivatives of stationary solid electrodes 2. : Voltammetry of 3,3' dibromo - 2,2,4,4 - tetramethylpentane in dmf
Ring baffle pressure distribution and slosh damping in large cylindrical tanks
An investigation was conducted to determine the pressure loads and damping associated with rigid ring baffles in relatively large cylindrical tanks. The radial and circumferential pressure distribution, as well as the damping, was measured on a ring baffle subjected to fundamental antisymmetric slosh in a 284-cm-diameter rigid tank. Experimental and analytical data are presented as a function of slosh velocity or amplitude, baffle spacing, and baffle locations both above and below the liquid surface. Results suggest that pressure distributions and damping values can be determined from available theories for the design of single and multiple baffle configurations
A storage and access architecture for efficient query processing in spatial database systems
Due to the high complexity of objects and queries and also due to extremely
large data volumes, geographic database systems impose stringent requirements on their
storage and access architecture with respect to efficient query processing. Performance
improving concepts such as spatial storage and access structures, approximations, object
decompositions and multi-phase query processing have been suggested and analyzed as
single building blocks. In this paper, we describe a storage and access architecture which
is composed from the above building blocks in a modular fashion. Additionally, we incorporate
into our architecture a new ingredient, the scene organization, for efficiently
supporting set-oriented access of large-area region queries. An experimental performance
comparison demonstrates that the concept of scene organization leads to considerable
performance improvements for large-area region queries by a factor of up to 150
A numerical study of the 2:1 planetary resonance
Astronomy and Astrophysics, 453, pp. 341-348, http://dx.doi.org./10.1051/0004-6361:20054655International audienc
Relative velocities among accreting planetesimals in binary systems: the circumprimary case
We investigate classical planetesimal accretion in a binary star system of
separation ab<50AU by numerical simulations, with particular focus on the
region at a distance of 1 AU from the primary. The planetesimals orbit the
primary, are perturbed by the companion and are in addition subjected to a gas
drag force. We concentrate on the problem of relative velocities dv among
planetesimals of different sizes. For various stellar mass ratios and binary
orbital parameters we determine regions where dv exceed planetesimal escape
velocities v_esc (thus preventing runaway accretion) or even the threshold
velocity v_ero for which erosion dominates accretion. Gaseous friction has two
crucial effects on the velocity distribution: it damps secular perturbations by
forcing periastron alignment of orbits, but at the same time the
size--dependence of this orbital alignment induces a significant dv increase
between bodies of different sizes. This differential phasing effect proves very
efficient and almost always increases dv to values preventing runaway
accretion, except in a narrow domain of almost circular companion orbits. The
erosion threshold dv>v_ero is reached in a wide (ab,eb) space for small (<10km)
planetesimals, but in a much more limited region for bigger ~50km objects. In
the intermediate v_esc<dv < v_ero domain, a possible growth mode would be the
type II runaway growth identified by Kortenkmap et al.(2001)Comment: to appear in Icarus (accepted 30 january 2006
The value of time-to-onset in statistical signal detection of adverse drug reactions:a comparison with disproportionality analysis in spontaneous reports from the Netherlands
PURPOSE: In pharmacovigilance, the commonly used disproportionality analysis (DPA) in statistical signal detection is known to have its limitations. The aim of this study was to investigate the value of the time to onset (TTO) of ADRs in addition to DPA.METHODS: We performed a pilot study using individual case safety reports (ICSRs) for three drugs (Cervarix®, nitrofurantoin and simvastatin) from the Lareb spontaneous reporting database. TTO distributions for drug - ADR associations were compared to other ADRs for the same drug and to other drugs for the same ADR using two-sample Anderson-Darling testing. Statistically significant associations were considered true positive (TP) signals if the association was present in the official product information of the drug. Sensitivity and specificity for the TTO method were compared with the DPA method. As a measure of disproportionality, the reporting odds ratio (ROR) was used.RESULTS: In general, sensitivity was lower, and specificity was higher for the TTO method compared to DPA. The TTO method showed similar sensitivity for all three drugs, whereas specificity was lower for Cervarix®. Eight additional TP signals were found using the TTO method compared to DPA.CONCLUSIONS: Our study shows that statistical signal detection based on the TTO alone resulted in a limited number of additional signals compared to DPA. We therefore conclude that the TTO method is of limited value for full database statistical screening in our setting. Copyright © 2016 John Wiley & Sons, Ltd.</p
Two subsets of human alphoid repetitive DNA show distinct preferential localization in the pericentromeric heterochromatin of chromosomes 13, 21 and 18
Ladino Clover For Rotation Pastures
Used in pasture mixtures, Ladino clover has shown most promise in northeast Iowa for dairy pastures. But you may expect satisfactory results wherever soil is fertile and well supplied with moisture
Epidemiology of coagulase-negative staphylococci intramammary infection in dairy cattle and the effect of bacteriological culture misclassification
- …