A quantitative analysis of time series of ultraviolet spectra from a sample of 10 bright O-type stars (cf. Kaper et al. 1996, Paper I) is presented. Migrating discrete absorption components (DACs), responsible for the observed variability in the UV resonance doublets, are modeled. To isolate the DACs from the underlying P Cygni lines, a method is developed to construct a template (" least-absor...

Social networks provide a wealth of data to study relationship dynamics among people. Most social networks such as Epinions and Facebook allow users to declare trusts or friendships with other users. Some of them also allow users to declare distrusts or negative relationships. When both positive and negative links co-exist in a network, some interesting community structures can be studied. In t...

As the work for managing a whole network effectively without a limited purpose, there is the work of PBNM (Policy-based network management). PBNM has two structural problems such as communication concentration from many clients to a communication control mechanism called PEP (Policy Enhancement Point) and the necessity of the network system updating at the time of introducing PBNM into LAN. Mor...

The mature vertebrate retina is a highly ordered neuronal network of cell bodies and synaptic neuropils arranged in distinct layers. Little, however, is known about the emergence of this spatial arrangement. Here, we investigate how the three main types of retinal inhibitory neuron (RIN)--horizontal cells (HCs), inner nuclear layer amacrine cells (iACs) and displaced amacrine cells (dACs)--reac...

Spectral lines formed in stellar winds from OB stars are observed to exhibit profile variations. Discrete Absorption Components (DACs) show a remarkably slow wavelength drift with time. In a straightforward interpretation, this is in sharp contradiction to the steep velocity law predicted by the radiation-driven wind theory, and by semi-empirical profile fitting. In the present paper we re-disc...

This paper presents a pragmatic way of implementing content-based publish/subscribe in a strongly typed object-oriented language. In short, we use structural reflection to implement filter objects through which applications express their subscription patterns. Our approach is pragmatic in the sense that it alleviates the need for any specific subscription language. It preserves encapsulation of...

Introduction A common use of high-resolution digital-to-analog converters (DACs) is providing controllable precision voltages. Applications for DACs with resolution up to 20 bits, precision up to 1 ppm, and reasonable speed include gradient coil control in medical MRI systems; precision dc sources in test and measurement; precision set-point and position control in mass spectrometry and gas chr...

In the last years the technology improvements of Digital-to-Analog Converters (DACs) has extended the use of digital techniques in a multitude of applications. Consequently, there is an increasing attention to DAC topics, from researchers and manufacturers. The paper is aimed at providing a metrological overview and the leading trends of the research in the field of DACs. 2005 Elsevier Ltd. All...

This paper describes the design and experimental evaluation of a multibit Sigma-Delta modulator with enhanced dynamic range (DR) through the use of nonlinear digital-to-analog converters (DACs) in the feedback paths. This nonlinearity imposes a trade-off between DR and distortion, which is well suited to the intended hearing aid application. The modulator proposed here uses a fully-differential...

One of the great challenges facing atomically dispersed catalysts, including single-atom catalysts (SACs) and double-atom (DACs), is their ultralow metal loading (typically less than 5 wt %), which limits practical catalytic applications, such as in oxygen-reduction reaction (ORR), crucial for hydrogen fuel cells metal-air batteries. Although some important progress has been achieved ultrahigh-...