High-field irreversible moment reorientation in the antiferromagnet Fe1.1_{1.1}Te

Magnetization measurements have been performed on single-crystalline Fe$_{1.1}$Te in pulsed magnetic fields $\mathbf{H}\perp\mathbf{c}$ up to 53 T and temperatures from 4.2 to 65 K. At $T=4.2$ K, a non-reversible reorientation of the antiferromagnetic moments is observed at $\mu_0H_R=48$ T as the pulsed field is on the rise. No anomaly is observed at $H_R$ during the fall of the field and, as long as the temperature is unchanged, during both rises and falls of additional field pulses. The transition at $H_R$ is reactivated if the sample is warmed up above the N\'{e}el temperature $T_N\simeq60$ K and cooled down again. The magnetic field-temperature phase diagram of Fe$_{1.1}$Te in $\mathbf{H}\perp\mathbf{c}$ is also investigated. We present the temperature dependence of $H_R$, as well as that of the antiferromagnetic-to-paramagnetic borderline $H_c$ in temperatures above 40 K.Comment: 5 pages, 4 figure

A 31T split-pair pulsed magnet for single crystal x-ray diffraction at low temperature

We have developed a pulsed magnet system with panoramic access for synchrotron x-ray diffraction in magnetic fields up to 31T and at low temperature down to 1.5 K. The apparatus consists of a split-pair magnet, a liquid nitrogen bath to cool the pulsed coil, and a helium cryostat allowing sample temperatures from 1.5 up to 250 K. Using a 1.15MJ mobile generator, magnetic field pulses of 60 ms length were generated in the magnet, with a rise time of 16.5 ms and a repetition rate of 2 pulses/hour at 31 T. The setup was validated for single crystal diffraction on the ESRF beamline ID06

The instrument suite of the European Spallation Source

An overview is provided of the 15 neutron beam instruments making up the initial instrument suite of the European Spallation Source (ESS), and being made available to the neutron user community. The ESS neutron source consists of a high-power accelerator and target station, providing a unique long-pulse time structure of slow neutrons. The design considerations behind the time structure, moderator geometry and instrument layout are presented. The 15-instrument suite consists of two small-angle instruments, two reflectometers, an imaging beamline, two single-crystal diffractometers; one for macromolecular crystallography and one for magnetism, two powder diffractometers, and an engineering diffractometer, as well as an array of five inelastic instruments comprising two chopper spectrometers, an inverse-geometry single-crystal excitations spectrometer, an instrument for vibrational spectroscopy and a high-resolution backscattering spectrometer. The conceptual design, performance and scientific drivers of each of these instruments are described. All of the instruments are designed to provide breakthrough new scientific capability, not currently available at existing facilities, building on the inherent strengths of the ESS long-pulse neutron source of high flux, flexible resolution and large bandwidth. Each of them is predicted to provide world-leading performance at an accelerator power of 2 MW. This technical capability translates into a very broad range of scientific capabilities. The composition of the instrument suite has been chosen to maximise the breadth and depth of the scientific impact o

A new model of shoaling and breaking waves. Part II. Run-up and two-dimensional waves

We derive a two-dimensional depth-averaged model for coastal waves with both dispersive and dissipative effects. A tensor quantity called enstrophy models the subdepth large-scale turbulence, including its anisotropic character, and is a source of vorticity of the average flow. The small-scale turbulence is modelled through a turbulent-viscosity hypothesis. This fully nonlinear model has equivalent dispersive properties to the Green-Naghdi equations and is treated, both for the optimization of these properties and for the numerical resolution, with the same techniques which are used for the Green-Naghdi system. The model equations are solved with a discontinuous Galerkin discretization based on a decoupling between the hyperbolic and non-hydrostatic parts of the system. The predictions of the model are compared to experimental data in a wide range of physical conditions. Simulations were run in one-dimensional and two-dimensional cases, including run-up and run-down on beaches, non-trivial topographies, wave trains over a bar or propagation around an island or a reef. A very good agreement is reached in every cases, validating the predictive empirical laws for the parameters of the model. These comparisons confirm the efficiency of the present strategy, highlighting the enstrophy as a robust and reliable tool to describe wave breaking even in a two dimensional context. Compared with existing depth-averaged models, this approach is numerically robust and adds more physical effects without significant increase in numerical complexity

A workflow to process 3D+time microscopy images of developing organisms and reconstruct their cell lineage

The quantitative and systematic analysis of embryonic cell dynamics from in vivo 3D+time image data sets is a major challenge at the forefront of developmental biology. Despite recent breakthroughs in the microscopy imaging of living systems, producing an accurate cell lineage tree for any developing organism remains a difficult task. We present here the BioEmergences workflow integrating all reconstruction steps from image acquisition and processing to the interactive visualization of reconstructed data. Original mathematical methods and algorithms underlie image filtering, nucleus centre detection, nucleus and membrane segmentation, and cell tracking. They are demonstrated on zebrafish, ascidian and sea urchin embryos with stained nuclei and membranes. Subsequent validation and annotations are carried out using Mov-IT, a custom-made graphical interface. Compared with eight other software tools, our workflow achieved the best lineage score. Delivered in standalone or web service mode, BioEmergences and Mov-IT offer a unique set of tools for in silico experimental embryology