Spin-dependent electron-proton scattering in the Delta-excitation region

We report on measurements of the cross section and provide first data on spin correlation parameters A(TT') and A(TL') in inclusive scattering of longitudinally polarized electrons from nuclear-polarized hydrogen. Polarized electrons were injected into an electron storage ring operated at a beam energy of 720 MeV. Polarized hydrogen was produced by an atomic beam source and injected into an open-ended cylindrical cell, located in the electron storage ring. The four-momentum transfer squared ranged from Q2 = 0.2 GeV(2)/c(2) at the elastic scattering peak to Q2 = 0.11 GeV(2)/c(2) at the Delta(1232) resonance. The data provide a stringent test of pion electroproduction models.     

Turbulence Plus

This paper attempts to give a concise overview of the turbulence research performed at the Laboratory for Aero and Hydrodynamics of the Delft University of Technology under the guidance of Frans Nieuwstadt. Frans Nieuwstadt was appointed in 1986 as director of the laboratory, and he held this position until his sudden death in 2005. Frans’ principal interest was to investigate turbulence at a fundamental level, but also to consider turbulence and its role in other processes. He coined a name for this research: turbulence plus.     

Control of a coupled map lattice model for vortex shedding in the wake of a cylinder

The flow behind a vibrating flexible cable at low Reynolds numbers can exhibit complex wake structures such as lace-like patterns, vortex dislocations and frequency cells. These structures have been observed in experiments and numerical simulations, and are predicted by a previously developed low-order coupled map lattice (CML). The discrete (in time and space) CML models consist of a series of diffusively coupled circle map oscillators along the cable span. Motivated by a desire to modify the complex wake patterns behind flexible vibrating cables we have studied the addition of control terms into the highly efficient CML models and explored the resulting dynamics. Proportional, adaptive proportional and discontinuous non-linear (DNL) control methods were used to derive the control laws. The first method employed occasional proportional feedback. The adaptive method used spatio-temporal feedback control. The DNL method used a discontinuous feedback linearization procedure, and the controller was designed for the resulting linearized system using eigenvalue assignment. These techniques were applied to a modeled vortex dislocation structure in the wake of a vibrating cable in uniform freestream flow. Parallel shedding patterns were achieved for a range of forcing frequency-forcing amplitude combinations studied to validate the control theory. The adaptive proportional and DNL methods were found to be more effective than the proportional control method due to the incorporation of a spatially varying feedback gain across the cylinder span. The DNL method was found to be the most efficient controller of the low-order CML model. The required control level across the cable span was correlated to the 1/1 lock-on behavior of the temporal circle map.     

The development of information storage materials — How microscopy can help?

The response of giant magnetoresistance (GMR) devices depends critically on the film microstructure, with parameters such as layer thickness and interfacial abruptness being crucial. This paper presents results obtained using high resolution electron microscopy (HREM), chemical mapping and atom probe microanalysis. Local variations in the magnetic properties are induced by the microstructure and also when the films are patterned to form small elements. These lead to changes in the magnetization reversal mechanism. Some results of the studies of the magnetization reversal carried out using in situ in Lorentz transmission electron microscopy (LTEM) magnetizing experiments are also included.     

The Effect of Oxandrolone on Voice Frequency in Growth Hormone-Treated Girls With Turner Syndrome

Objectives/Hypothesis

Oxandrolone (Ox) increases height gain but may also cause voice deepening in growth hormone (GH)-treated girls with Turner syndrome (TS). We assessed the effect of Ox on objective and subjective speaking voice frequency in GH-treated girls with TS.

Study Design

A multicenter, randomized, placebo (Pl)-controlled, double-blind study was conducted.

Methods

One hundred thirty-three patients were included and treated with GH (1.33 mg/m²/d) from baseline, combined with Pl or Ox in a low (0.03 mg/kg/d) or conventional (0.06 mg/kg/d) dose from the age of 8 years and estrogens from the age of 12 years. Yearly from starting Ox/Pl until 6 months after discontinuing GH + Ox/Pl, voices were recorded and questionnaires were completed.

Results

At start, mean (±standard deviation [SD]) voice frequency SD score (SDS) was high for age (1.0 ± 1.2, P < 0.001) but normal for height. Compared with GH + Pl, voices tended to lower on GH + Ox 0.03 (P = 0.09) and significantly lowered on GH + Ox 0.06 (P = 0.007). At the last measurement, voice frequency SDS was still relatively high in GH + Pl group (0.6 ± 0.7, P = 0.002) but similar to healthy girls in both GH + Ox groups. Voice frequency became lower than −2 SDS in one patient (3%) on GH + Ox 0.03 and three patients (11%) on GH + Ox 0.06. The percentage of patients reporting subjective voice deepening was similar between the dosage groups.

Conclusions

Untreated girls with TS have relatively high-pitched voices. The addition of Ox to GH decreases voice frequency in a dose-dependent way. Although most voice frequencies remain within the normal range, they may occasionally become lower than −2 SDS, especially on GH + Ox 0.06 mg/kg/d.     

Evaluation of diverse α/β-backbone patterns for functional α-helix mimicry: analogues of the Bim BH3 domain

Peptidic oligomers that contain both α- and β-amino acid residues, in regular patterns throughout the backbone, are emerging as structural mimics of α-helix-forming conventional peptides (composed exclusively of α-amino acid residues). Here we describe a comprehensive evaluation of diverse α/β-peptide homologues of the Bim BH3 domain in terms of their ability to bind to the BH3-recognition sites on two partner proteins, Bcl-x(L) and Mcl-1. These proteins are members of the anti-apoptotic Bcl-2 family, and both bind tightly to the Bim BH3 domain itself. All α/β-peptide homologues retain the side-chain sequence of the Bim BH3 domain, but each homologue contains periodic α-residue → β(3)-residue substitutions. Previous work has shown that the ααβαααβ pattern, which aligns the β(3)-residues in a 'stripe' along one side of the helix, can support functional α-helix mimicry, and the results reported here strengthen this conclusion. The present study provides the first evaluation of functional mimicry by ααβ and αααβ patterns, which cause the β(3)-residues to spiral around the helix periphery. We find that the αααβ pattern can support effective mimicry of the Bim BH3 domain, as manifested by the crystal structure of an α/β-peptide bound to Bcl-x(L), affinity for a variety of Bcl-2 family proteins, and induction of apoptotic signaling in mouse embryonic fibroblast extracts. The best αααβ homologue shows substantial protection from proteolytic degradation relative to the Bim BH3 α-peptide.     

Experiments on the Flow Field and Acoustic Properties of a Mach number 0·75 Turbulent Air Jet at a Low Reynolds Number

In this paper we present the experimental results of a detailed investigation of the flow and acoustic properties of a turbulent jet with Mach number 0·75 and Reynolds number 3·5 10³. We describe the methods and experimental procedures followed during the measurements, and subsequently present the flow field and acoustic field. The experiment presented here is designed to provide accurate and reliable data for validation of Direct Numerical Simulations of the same flow. Mean Mach number surveys provide detailed information on the centreline mean Mach number distribution, radial development of the mean Mach number and the evolution of the jet mixing layer thickness both downstream and in the early stages of jet development. Exit conditions are documented by measuring the mean Mach number profile immediately above the nozzle exit. The fluctuating flow field is characterised by means of a hot-wire, which produced radial profiles of axial turbulence at several stations along the jet axis and the development of flow fluctuations through the jet mixing layer. The axial growth rate of the jet instabilities are determined as function of Strouhal number, and the axial development of several spectral components is documented. The directivity of the overall sound pressure level and several spectral components were investigated. The spectral content of the acoustic far field is shown to be compatible with findings of hot-wire experiments in the mixing layer of the jet. In addition, the measured acoustic spectra agree with Tam’s large-scale similarity and fine-scale similarity spectra (Tam et al., AIAA Pap 96, 1996).     

Phase diagrams of CuCl2·2NC5H5 and CsCuCl3

The phase diagrams of two quasi one-dimensional,$\text{S =}\text{1}\text{2}$ quantum systems CuCl₂·2NC₅H₅ and CsCuCl₃, have been determined experimentally for fields between 0 and 90 kOe. The results show an increase of the Néel temperature as a function of the field, in accordance with earlier observations on manganese systems.