9,342 research outputs found
Scattering of Two Spinless Particles in 3D Formulation with Coulomb Admixtures
Scattering of two spinless charge particles for simple forces including
coulomb admixtures is calculated without partial wave decomposition. The
coulomb interaction being taken is of the type of screened coulomb potential.
For the forces range are not infinite, the standard scattering theory is
applied. The differential and total cross section is calculated and coulomb
effects are shown.Comment: 4 pages, 2 figure
Reply to "Comment on 'Fano resonance for Anderson Impurity Systems' "
In a recent Comment, Kolf et al. (cond-mat/0503669) state that our analysis
of the Fano resonance for Anderson impurity systems [Luo et al., Phys. Rev.
Lett 92, 256602 (2004)] is incorrect. Here we want to point out that their
comments are not based on firm physical results and their criticisms are
unjustified and invalid.Comment: 1 page, 1 figure, to appear in PR
Towards an expert system for enantioseparations: induction of rules using machine learning
A commercially available machine induction tool was used in an attempt to automate the acquisition of the knowledge needed for an expert system for enantioseparations by High Performance Liquid Chromatography using Pirkle-type chiral stationary phases (CSPs). Various rule-sets were induced that recommended particular CSP chiral selectors based on the structural features of an enantiomer pair. The results suggest that the accuracy of the optimal rule-set is 63% + or - 3% which is more than ten times greater than the accuracy that would have resulted from a random choice
Magnetoresistance, noise properties and the Koshino-Taylor effect in the quasi-1D oxide KRu_4O_8
The low temperature electronic and galvanomagnetic transport properties of
the low dimensional oxide KRu_4O_8 are experimentally considered. A quadratic
temperature variation of the resistivity is observed to be proportional to the
residual resistivity. It shows the role of inelastic electron scattering
against impurities, i.e. a large Koshino-Taylor effect, rather than a
consequence of strong electronic correlations. In the same temperature range,
the Kohler rule is not fulfilled. The resistance noise increases also sharply,
possibly due to a strong coupling of carriers with lattice fluctuations in this
low dimensional compound.Comment: accepted for publication in Europhysics Lette
The OPERA trial : a protocol for the process evaluation of a randomised trial of an exercise intervention for older people in residential and nursing accommodation
Background: The OPERA trial is large cluster randomised trial testing a physical activity intervention to address
depression amongst people living in nursing and residential homes for older people. A process evaluation was
commissioned alongside the trial and we report the protocol for this process evaluation. Challenges included the
cognitive and physical ability of the participants, the need to respect the privacy of all home residents, including
study non-participants, and the physical structure of the homes. Evaluation activity had to be organised around the
structured timetable of homes, leaving limited opportunities for data collection. The aims of this process evaluation
are to provide findings that will assist in the interpretation of the clinical trial results, and to inform potential
implementation of the physical activity intervention on a wider scale.
Methods/design: Quantitative data on recruitment of homes and individuals is being collected. For homes in the
intervention arm, data on dose and fidelity of the intervention delivered; including individual rates of participation
in exercise classes are collected. In the control homes, uptake and delivery of depression awareness training is
monitored. These data will be combined with qualitative data from an in-depth study of a purposive sample of
eight homes (six intervention and two control).
Discussion: Although process evaluations are increasingly funded alongside trials, it is still rare to see the findings
published, and even rarer to see the protocol for such an evaluation published. Process evaluations have the
potential to assist in interpreting and understanding trial results as well as informing future roll-outs of
interventions. If such evaluations are funded they should also be reported and reviewed in a similar way to the
trial outcome evaluation
A review of expert systems for chromatography
Expert systems for chromatography are reviewed. A taxonomy is proposed that allows present (and future) expert systems in this area to be classified and facilitates an understanding of their inter-relationship. All the systems are described focusing on the reasons for their development, what their purpose was and how they were to be used. The engineering methods, knowledge representations, tools and architectures used for the systems are compared and contrasted in a discussion covering all the stages of the development life cycle of expert systems. The review reveals that too often developers of expert systems for chromatography do not justify their decisions on engineering matters and that the literature suggests that many ideas advocated by knowledge engineers are not being used
Transcriptome-wide analysis reveals different categories of response to a standardised immune challenge in a wild rodent
Individuals vary in their immune response and, as a result, some are more susceptible to infectious disease than others. Little is known about the nature of this individual variation in natural populations, or which components of immune pathways are most responsible, but defining this underlying landscape of variation is an essential first step to understanding the drivers of this variation and, ultimately, predicting the outcome of infection. We describe transcriptome-wide variation in response to a standardised immune challenge in wild field voles. We find that markers can be categorised into a limited number of types. For the majority of markers, the response of an individual is dependent on its baseline expression level, with significant enrichment in this category for conventional immune pathways. Another, moderately sized, category contains markers for which the responses of different individuals are also variable but independent of their baseline expression levels. This category lacks any enrichment for conventional immune pathways. We further identify markers which display particularly high individual variability in response, and could be used as markers of immune response in larger studies. Our work shows how a standardised challenge performed on a natural population can reveal the patterns of natural variation in immune response
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