Loaded wedge bow-tie antenna using linear profile

The influence of a linear loading profile on a slitted bow-tie antenna is discussed. Improvements of the radiation characteristics are achieved by bending the antenna. Simulations and measurements show a S ₁₁ 10 dB bandwidth of more than 8:1 and a gain larger than 4.5 dBi. A complete antenna system matched to 50 Ω is proposed     

Sortieren bei virtuellem Speicher

In this paper the behavior of sorting methods in a paging environment is studied. We give an algorithm which has a page fault rate always independant of the numbern of records in the file to be sorted and depending only on the number of pages required for the file. The expected number of page exceptions has with 0(p logp) the same order of magnitude as with the classic quicksort procedure but is by the factor 2 lower and we avoid the dependance onn in cases, when the sequence is in partial order.     

Differential expression of CD22 (Lyb8) on murine B cells

Previous studies have established the distribution, biochemistry and functional attributes of human CD22, a B cell-restricted glycoprotein. Recently, molecular cloning of the murine CD22 equivalent revealed this molecule to be the same as the previously described Lyb8 alloantigen. Using the anti-Lyb8 mAb Cy34.1.2, the present report documents the expression patterns of CD22 within the murine B cell compartment. The results demonstrate that in the bone marrow, murine CD22 is absent on the surface of pro-B cells, pre-B cells and newly emerging IgM+ B cells. CD22 is present at a low density on immature IgMhi B cells and fully expressed on mature recirculating B cells. In the periphery, murine CD22 is expressed at mature levels on all B cell subsets including follicular, marginal zone, B1 and switched B cells. Further studies showed CD22 to be retained on activated murine B cells for extended periods. Finally, in combination with CD23 and heat stable antigen, CD22 can be used to delineate the immature splenic B cells, and distinguish them from follicular and marginal zone cells. Together, the results demonstrate murine CD22 to be a useful pan marker for all mature B cell subsets.     

Die Flexibilisierung der "Behinderung"

Zusammenfassung  Der Beitrag fragt nach dem Stellenwert des Normalitätsbegriffs im Diskurs der Behinderung. Ausgangspunkt ist die These, dass Normalität und Normativität analytisch voneinander getrennt werden müssen. In der heutigen Normalisierungsgesellschaft existieren sowohl wertbezogene, präskriptive ("normative") als auch statistisch fundierte, deskriptive ("normalistische") Normen. Außerdem lassen sich zwei Normalisierungsstrategien kennzeichnen: ein starr ausgrenzender, normierender Ansatz ("Protonormalismus") und eine flexible, normalisierende Strategie ("flexibler Normalismus"). Auf dieser theoretischen Folie wird diskutiert, ob sich im behindertenpolitischen Diskurs und in sozialpolitischen Konzepten Tendenzen der flexiblen Normalisierung auffinden lassen. Der Schwerpunkt des Beitrags liegt auf einer normalitätstheoretischen Analyse der beiden Klassifikationsmodelle der Weltgesundheitsorganisation. Die "International Classification of Impairments, Disabilities and Handicaps" (ICIDH 1980) blieb noch der wertbezogenen Normativität verhaftet. Dagegen stellt die "International Classification of Functioning, Disability and Health" (ICF 2001) die normalistische (Vergleichs-)Norm ins Zentrum und formuliert das Gebot der Selbstnormalisierung.

Three-dimensional CAD-based mesh Generator for the Dey-Mittra conformal FDTD algorithm

It is well-known that the finite-difference time-domain (FDTD) method is subject to significant errors due to the staircasing of surfaces that are not precisely aligned with major grid planes. Dey and Mittra introduced a locally conformal method (D-FDTD) that has shown substantial gains in the accuracy of modeling arbitrary surfaces in the FDTD grid. A mesh generator for this purpose was reported by Yu and Mittra. In this paper, we present the formulation and validation of an alternative CAD-based mesh generator for D-FDTD that has improved capabilities for arbitrary three-dimensional (3-D) perfect electric conductor (PEC) geometries. This mesh generator is capable of importing AutoCad and ProE files of 3-D PEC scatterers and resonators. It can reduce the required FDTD grid resolution by up to 4:1 in each Cartesian direction in 3-D relative to conventional staircased FDTD models when modeling cavity resonances of complex PEC structures such as twisted waveguides.     

Regional suppurative lymphadenitis after BCG vaccination (author's transl)

In the first half of 1975 there occurred in the Federal Republic of Germany an unusual rise in the incidence of suppurative inguinal lymphadenitis after BCG vaccination of newborns, in immediate time relation with change of the vaccine by its manufacturers, Behringwerke. The attenuated daughter strain G?teborg had been replaced by the effective but also rather aggressive strain Copenhagen 1331. The complication rate was 1.5% in West Berlin. Clinical course, operative technique as well as microbiological and histomorphological features of these cases were analyzed in a joint study. Since it is likely that, after re-admission of the Copenhagen vaccine, such complications may again occur despite reduced micro-organism count, vaccination of newborns should in future be restricted to those at risk.     

In vitro and in vivo MR imaging of hyaline cartilage: zonal anatomy, imaging pitfalls, and pathologic conditions

Hyaline cartilage plays an essential role in the maintenance of normal synovial joint function by reducing friction and distributing loads. Histologic analysis of hyaline cartilage reveals zonal variation in cellular morphology, proteoglycan concentration, and collagen fiber size and orientation. High-resolution magnetic resonance (MR) imaging reveals an analogous laminar anatomy that is often visible on clinical images obtained with proper attention to technique. In vitro and in vivo pulse sequences show three distinct laminae: a hypointense superficial lamina, a hyperintense intermediate lamina, and a heterogeneous deep lamina that consists of alternating hyperintense and hypointense bands perpendicular to the subchondral bone. Imaging pitfalls include magic angle effects, truncation artifact, partial volume effect, regional anatomic variation, chemical shift, and magnetic susceptibility effects. Pathologic conditions that affect articular cartilage include chondromalacia patellae, osteoarthritis, and localized traumatic lesions. Although detection of early cartilage disease remains elusive, MR imaging can demonstrate intermediate and advanced lesions.     

Complete RF system model for analysis of compact MIMO arrays

A framework to analyze compact arrays for multiple-input-multiple-output (MIMO) is presented. Many handheld devices require very compact arrays. Small spacings between the antennas lead to mutual coupling, which decreases the efficiency of the antennas and therefor the signal-to-noise ratio and leads to correlated signals at the antennas. Both effects are completely taken into account in this framework; thus, it allows for a fair comparison of different antenna arrays for MIMO. It is distinguished between MIMO systems for multiplex transmission or pure beamforming, which have different requirements for the antennas. Different compact array configurations, which exploit spatial, polarization, and pattern diversity, are discussed and compared. For practical purposes, it is also shown how to connect this framework to standard path-based channel models.     

A Self Distributing Virtual Machine for Adaptive Multicore Environments

The use of parallel systems is no longer limited to dedicated clusters as multicore chips are more and more appearing in embedded applications. To meet power, performance and cost targets these systems need to be adaptive. The reconfiguration features of recent FPGAs make new approaches for this type of parallel computing possible: Dynamic reconfiguration at runtime offers an important step to adaptive behavior of systems-on-chip (SoCs). This article analyzes the challenges of such an adaptive SoC. It is shown that many of the requirements for an adaptive FPGA-realization are met by the SDVM, the scalable dataflow-driven virtual machine which has been successfully implemented and tested on a cluster of workstations. The SDVM has evolved to a virtualization layer for multicore-FPGAs, now called SDVM ^R . This virtualization layer allows a transparent runtime-reconfiguration of the underlying hardware to adapt to the changing system environment. Results for a basic application for both systems are presented.