14,901 research outputs found
Experiences with applying a genetic algorithm to determine an information systems architecture
While determining information systems architectures (ISA), business systems planning (BSP) is a well-known method to join processes and data classes to subsystems. BSP matrices have generally been rearranged without describing the underlying methods. Meanwhile, various techniques have been developed for solving the ISA problem. Since exact optimization methods often fail to provide results for large ISA problems, different heuristics have been applied. A new heuristic for solving the ISA problem is the application of genetic algorithms (GA). This paper examines the application of a simple GA to the ISA problem and compares the results of applying the GA with those obtained by exact method
Remarkable change of tunneling conductance in YBCO films in fields up to 32.4T
We studied the tunneling density of states in YBCO films under strong
currents flowing along node directions. The currents were induced by fields of
up to 32.4T parallel to the film surface and perpendicular to the
planes. We observed a remarkable change in the tunneling conductance at high
fields where the gap-like feature shifts discontinuously from 15meV to a lower
bias of 11meV, becoming more pronounced as the field increases. The effect
takes place in increasing fields around 9T and the transition back to the
initial state occurs around 5T in decreasing fields. We argue that this
transition is driven by surface currents induced by the applied magnetic field.Comment: 4 pages, 7 figure
Quantum interference and non-locality of independent photons from disparate sources
We quantitatively investigate the non-classicality and non-locality of a
whole new class of mixed disparate quantum and semiquantum photon sources at
the quantum-classical boundary. The latter include photon added thermal and
photon added coherent sources, experimentally investigated recently by Zavatta
et al. [Phys. Rev. Lett. 103, 140406 (2009)]. The key quantity in our
investigations is the visibility of the corresponding photon-photon correlation
function. We present explicit results on the violations of the Cauchy-Schwarz
inequality - which is a measure of nonclassicality - as well as of Bell-type
inequalities.Comment: 9 pages, 3 figure
Pumilio binds para mRNA and requires nanos and brat to regulate sodium current in drosophila motoneurons
Homeostatic regulation of ionic currents is of paramount importance during periods of synaptic growth or remodeling. Our previous work has identified the translational repressor Pumilio (Pum) as a regulator of sodium current (INa) and excitability in Drosophila motoneurons. In this current study, we show that Pum is able to bind directly the mRNA encoding the Drosophila voltage-gated sodium channel paralytic (para). We identify a putative binding site for Pum in the 3' end of the para open reading frame (ORF). Characterization of the mechanism of action of Pum, using whole-cell patch clamp and real-time reverse transcription-PCR, reveals that the full-length protein is required for translational repression of para mRNA. Additionally, the cofactor Nanos is essential for Pum-dependent para repression, whereas the requirement for Brain Tumor (Brat) is cell type specific. Thus, Pum-dependent regulation of INa in motoneurons requires both Nanos and Brat, whereas regulation in other neuronal types seemingly requires only Nanos but not Brat. We also show that Pum is able to reduce the level of nanos mRNA and as such identify a potential negative-feedback mechanism to protect neurons from overactivity of Pum. Finally, we show coupling between INa (para) and IK (Shal) such that Pum-mediated change in para results in a compensatory change in Shal. The identification of para as a direct target of Pum represents the first ion channel to be translationally regulated by this repressor and the location of the binding motif is the first example in an ORF rather than in the canonical 3'-untranslated region of target transcripts
An investigation of the occurrence of sv40 antibodies in South Africa
We developed an enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to simian virus 40 (SV40) in human serum. We then used the ELISA to test for anti-SV40 antibodies in healthy inviduals and patients suffering from cancer and renal diseases. The aim of the study was to determine the presence of antibodies against SV40 in sera of individuals who received the South African poliovirus vaccines from 1958 to the present. Detecting such antibodies could give an indication of whether any of the poliovirus vaccines used in South Africa were ever contaminated with the SV40 or not. A total of 5/164 samples were repeatedly positive for SV40 antibodies by the ELISA. Four of the samples were from the healthy population group and the remaining 1 (1/64) was from the patient group. An SV40 antibody-blocking assay and a Western blot were used as additional confirmation for the SV40 antibodies, whereas the Western blot assay developed a single common band on all 5 samples
Integrating patients' views into health technology assessment: Analytic hierarchy process (AHP) as a method to elicit patient preferences
Background: Patient involvement is widely acknowledged to be a valuable component in health technology assessment (HTA) and healthcare decision making. However, quantitative approaches to ascertain patients' preferences for treatment endpoints are not yet established. The objective of this study is to introduce the analytic hierarchy process (AHP) as a preference elicitation method in HTA. Based on a systematic literature review on the use of AHP in health care in 2009, the German Institute for Quality and Efficiency in Health Care (IQWiG) initiated an AHP study related to its HTA work in 2010. - \ud
Methods: The AHP study included two AHP workshops, one with twelve patients and one with seven healthcare professionals. In these workshops, both patients and professionals rated their preferences with respect to the importance of different endpoints of antidepressant treatment by a pairwise comparison of individual endpoints. These comparisons were performed and evaluated by the AHP method and relative weights were generated for each endpoint. - \ud
Results: The AHP study indicates that AHP is a well-structured technique whose cognitive demands were well handled by patients and professionals. The two groups rated some of the included endpoints of antidepressant treatment differently. For both groups, however, the same six of the eleven endpoints analyzed accounted for more than 80 percent of the total weight. - \ud
Conclusions: AHP can be used in HTA to give a quantitative dimension to patients' preferences for treatment endpoints. Preference elicitation could provide important information at various stages of HTA and challenge opinions on the importance of endpoints
Correlation between the Extraordinary Hall Effect and Resistivity
We study the contribution of different types of scattering sources to the
extraordinary Hall effect. Scattering by magnetic nano-particles embedded in
normal-metal matrix, insulating impurities in magnetic matrix, surface
scattering and temperature dependent scattering are experimentally tested. Our
new data, as well as previously published results on a variety of materials,
are fairly interpreted by a simple modification of the skew scattering model
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