The structure of blocks with a Klein four defect group

We prove Erdmann’s conjecture [16] stating that every block with a Klein four defect group has a simple module with trivial source, and deduce from this that Puig’s finiteness conjecture holds for source algebras of blocks with a Klein four defect group. The proof uses the classification of finite simple groups

Synthesis and kinetic resolution of N-Boc-2-arylpiperidines

The chiral base n-BuLi/(-)-sparteine or n-BuLi/(+)-sparteine surrogate promotes kinetic resolution of N-Boc-2-arylpiperidines by asymmetric deprotonation. The enantioenriched starting material was recovered with yields 39-48% and ers up to 97:3. On lithiation then electrophilic quench, 2,2-disubstituted piperidines were obtained with excellent yields and enantioselectivities. © 2014 the Partner Organisations

Pathological and Biological Differences Between Screen-Detected and Interval Ductal Carcinoma in situ of the Breast

Background: The incidence of ductal carcinoma in situ (DCIS) has risen dramatically with the introduction of screening mammography. The aim was to evaluate differences in pathological and biological characteristics between patients with screen-detected and interval DCIS. Methods: From January 1992 to December 2001, 128 consecutive patients had been treated for pure DCIS at our institute. From these, 102 had been attending the Dutch breast cancer screening program. Sufficient paraffin-embedded tissue was available in 74 out of the 102 cases to evaluate biological marker expression (Her2/neu, ER, PR, p53 and cyclin D1) on tissue microarrays (TMA group). Differences in clinicopathological characteristics and marker expression between screen-detected and interval patients were evaluated. Screen-detected DCIS was classified as DCIS detected by screening mammography, when the two-year earlier examination failed to reveal an abnormality. Interval patients were classified as patients with DCIS detected within the two-year interval between two subsequent screening rounds. Results: Screen-detected DCIS was related with linear branching and coarse granular microcalcifications on mammography (p < .001) and with high-grade DCIS according to the Van Nuys classification (p = .025). In univariate analysis, screen-detected DCIS was related with Her2/neu overexpression (odds ratio [OR] = 6.5; 95%CI 1.3-31.0; p = .020), and interval DCIS was associated with low-grade (Van Nuys, OR = 7.3; 95% CI 1.6-33.3; p = .010) and PR positivity (OR = 0.3; 95%CI 0.1-1.0; p = .042). The multivariate analysis displayed an independent relation of Her2/neu overexpression with screen-detected DCIS (OR = 12.8; 95%CI 1.6-104.0; p = .018). Conclusions: These findings suggest that screen-detected DCIS is biologically more aggressive than interval DCIS and should not be regarded as overdiagnosis

Low Engine Order NGV Only Tests at DLR

As part of the Brite/EuRam project &quot;Aeroelastic Design of Turbine Blades II&quot; (ADTurBII) low engine order (LEO) stator only experiments at 3 stator configurations with 43 nozzle guide vanes have been carried out in the windtunnel for rotating cascades (RGG) at DLR in Göttingen. Static pressures on the blade surfaces and total pressures in the stator exit flow fields were measured at different radial locations for a subsonic (0.85) and a supersonic (1.05) isentropic exit Mach number. Additional 2D-velocity vectors and turbulence quantities in the downstream flow fields have been detected by a Laser-2-Focus anemometer (L2F). Flow field measurements are covering at least one period of the low engine order (up to 9 stator pitches). Results in the exit flow fields were Fourier-analysed in order to determine their harmonic contents. Local homogeneous (pitchwise mixed out) flow field quantities were calculated from the inhomogeneous value

Low Engine Order Stage Tests at DLR (Time-Averaged Results)

As part of the Brite/EuRam project &quot;Aeroelastic Design of Turbine Blades II&quot; (ADTurBII) Low Engine Order (LEO) experiments in a high pressure turbine stage with stator coolant flow and throat area ariation have been carried out in the windtunnel for rotating cascades (RGG) at DLR in Göttingen. Total pressures in the rotor exit flow field were measured by pitot probe at up to 8 radial locations between 10% and 90% channel height. 2D-velocity vectors and turbulence intensities in the tator-rotor gap and in the rotor exit field were measured by a Laser-2-Focus (L2F) anemometer at 20%, 50% and 90% height. Investigations were performed for a low and high pressure ratio, covering at least one period of low engine order (up to 9 stator passages). Only time averaged results are presented and evaluated. A Fourier analysis reveals the harmonic contents of the low engine order flow field. Local homogeneous (mixed out) flow field quantities were calculated for every low engine order stator pitch

The structure of blocks with a Klein four defect group

We prove Erdmann's conjecture stating that every block with a Klein four defect group has a simple module with trivial source, and deduce from this that Puig's finiteness conjecture holds for source algebras of blocks with a Klein four defect group. The proof uses the classification of finite simple groups

The structure of blocks with a Klein four defect group, preprint

Abstract We prove Erdmann&apos;s conjectur

Comparison of Models to Predict Low Engine Order Excitation in a High Pressure Turbine Stage

The paper compares three numerical strategies to predict the aerodynamic rotor excitation sources of &quot;Low Engine Order&quot; (LEO) in a high-pressure turbine stage. Main focus is laid on methods to compute the stator exit flow. The aim is to evaluate computationally cheap approaches to avoid modelling the whole circumference of the stator. A single passage viscous strategy, a single passage inviscid linear blade movement strategy and a viscous multi passage sector strategy are compared and evaluated. The assessment of the prediction quality is made by comparison of the computed stator exit flow to experimental data. The main result is that only the global behaviour of the stator exit flow is estimated right, both level and amplitude of Mach number and pressure are computed with poor agreement to experiments. Future evaluations of the resulting rotor excitation pressure are needed to estimate the level of necessary agreement to give acceptable predictions of the low engine order forced response

Flow Measurements for Low Engine Order Excitations in a High Pressure Turbine Stage

This paper demonstrates and evaluates unique flow measurement results obtained in a high pressure test turbine, in order to analyze the effect of Low Engine Order (LEO) excitations. A stator was modified to induce LEO flow variations by either imposing a throat width variation or a blockage of the trailing edge cooling flow from some of the vanes. Laser Two Focus (L2F) and pressure probe measurements were performed at subsonic and transonic flow conditions, without and with the rotor installed and operated. Time resolved velocity data was obtained in front and inside of rotor passages covering the Low Engine Order variation period. The presented results evaluation focuses only on L2F measurements and show that the LEO variation of flow velocity and turbulence intensity is most visible in the gap between stator and rotor and at the first measurement location inside the rotor passage. The overall trend is that stator exit flow Mach numbers are higher behind the passages with smaller pitch and vice versa