VIS: the visible imager for Euclid

Euclid-VIS is a large format visible imager for the ESA Euclid space mission in their Cosmic Vision program, scheduled for launch in 2019. Together with the near infrared imaging within the NISP instrument it forms the basis of the weak lensing measurements of Euclid. VIS will image in a single r+i+z band from 550-900 nm over a field of view of ~0.5 deg2. By combining 4 exposures with a total of 2240 sec, VIS will reach to V=24.5 (10{\sigma}) for sources with extent ~0.3 arcsec. The image sampling is 0.1 arcsec. VIS will provide deep imaging with a tightly controlled and stable point spread function (PSF) over a wide survey area of 15000 deg2 to measure the cosmic shear from nearly 1.5 billion galaxies to high levels of accuracy, from which the cosmological parameters will be measured. In addition, VIS will also provide a legacy imaging dataset with an unprecedented combination of spatial resolution, depth and area covering most of the extra-Galactic sky. Here we will present the results of the study carried out by the Euclid Consortium during the Euclid Definition phase.Comment: 10 pages, 6 figure

Photoassociation of Ultracold CsYb Molecules and Determination of Interspecies Scattering Lengths

This thesis reports the first measurements of the ground state binding energies of CsYb molecules and the scattering lengths of the Cs+Yb system. The knowledge gained from these measurements will be essential for devising the most efficient route for the creation of rovibrational ground state CsYb molecules. CsYb molecules in the rovibrational ground state possess both electric and magnetic dipole moments which opens up a wealth of applications in many areas of physics and chemistry. In addition, we present the setup of a crossed beam optical dipole trap and the investigation of precooling and loading of Yb into the dipole trap. Evaporative cooling in the dipole trap results in the reliable production of Bose-Einstein condensates with $4 \times 10^{5}$ $^{174}$Yb atoms. We also describe the necessary changes required to cool fermionic $^{173}$Yb atoms and report the production of a six-component degenerate Fermi gas of $8 \times 10^{4}$ $^{173}$Yb atoms with a temperature of 0.3~$T_{\rm F}$. As well as the ability to cool Yb to degeneracy, we present the production of Bose-Einstein condensates containing $5 \times 10^{4}$ $^{133}$Cs atoms. Effective cooling of Cs is achieved using Degenerate Raman sideband cooling, which enables $6 \times 10^{7}$ Cs atoms to be cooled to below $2 \, \mu$K and polarised in the $\ket{F=3, m_{F}=+3}$ state with 90~\% efficiency. Finally, we report the production of ultracold heteronuclear Cs$^*$Yb and CsYb molecules using one-photon and two-photon photoassociation respectively. For the electronically excited Cs$^*$Yb molecules we use trap-loss spectroscopy to detect molecular states below the Cs($^{2}P_{1/2}$) + Yb($^{1}S_{0}$) asymptote. For $^{133}$Cs$^{174}$Yb, we observe 13 rovibrational states with binding energies up to $\sim$500\,GHz. In addition, we produce ultracold fermionic $^{133}$Cs$^{173}$Yb and bosonic $^{133}$Cs$^{172}$Yb and $^{133}$Cs$^{170}$Yb molecules. From mass scaling, we determine the number of vibrational levels supported by the 2(1/2) excited-state potential to be 154 or 155

HFE mutations, iron deficiency and overload in 10 500 blood donors

People with genetic haemochromatosis (GH) accumulate iron from excessive dietary absorption. In populations of northern European origin, over 90% of patients are homozygous for the C282Y mutation of the HFE gene. While about 1 in 200 people in the general population have this genotype the proportion who develop clinical haemochromatosis is not known. The influence of HFE genotype on iron status was investigated in 10 556 blood donors. The allele frequencies of the C282Y and H63D mutations were

A Concept for an STJ-based Spectrograph

We describe a multi-order spectrograph concept suitable for 8m-class telescopes, using the intrinsic spectral resolution of Superconducting Tunneling Junction detectors to sort the spectral orders. The spectrograph works at low orders, 1-5 or 1-6, and provides spectral coverage with a resolving power of R~8000 from the atmospheric cutoff at 320 nm to the long wavelength end of the infrared H or K band at 1800 nm or 2400 nm. We calculate that the spectrograph would provide substantial throughput and wavelength coverage, together with high time resolution and sufficient dynamic range. The concept uses currently available technology, or technologies with short development horizons, restricting the spatial sampling to two linear arrays; however an upgrade path to provide more spatial sampling is identified. All of the other challenging aspects of the concept - the cryogenics, thermal baffling and magnetic field biasing - are identified as being feasible.Comment: Accepted in Monthly Notices of the Royal Astronomical Society, 12 pages with 10 figure

Reduced cellularity of bone marrow in multiple sclerosis with decreased MSC expansion potential and premature ageing in vitro

Background: Autologous bone-marrow-derived cells are currently employed in clinical studies of cell-based therapy in multiple sclerosis (MS) although the bone marrow microenvironment and marrow-derived cells isolated from patients with MS have not been extensively characterised. Objectives: To examine the bone marrow microenvironment and assess the proliferative potential of multipotent mesenchymal stromal cells (MSCs) in progressive MS. Methods: Comparative phenotypic analysis of bone marrow and marrow-derived MSCs isolated from patients with progressive MS and control subjects was undertaken. Results: In MS marrow, there was an interstitial infiltrate of inflammatory cells with lymphoid (predominantly T-cell) nodules although total cellularity was reduced. Controlling for age, MSCs isolated from patients with MS had reduced in vitro expansion potential as determined by population doubling time, colony-forming unit assay, and expression of β-galactosidase. MS MSCs expressed reduced levels of Stro-1 and displayed accelerated shortening of telomere terminal restriction fragments (TRF) in vitro. Conclusion: Our results are consistent with reduced proliferative capacity and ex vivo premature ageing of bone-marrow-derived cells, particularly MSCs, in MS. They have significant implication for MSC-based therapies for MS and suggest that accelerated cellular ageing and senescence may contribute to the pathophysiology of progressive MS. </jats:sec

A Thermodynamic Theory of Neuromuscular Performance: Unifying Volume and Fatigue Through Entropy

Current exercise science lacks theoretical unity, treating training volume as mechanical work(repetitions × load) while describing fatigue through separate physiological models. Thisfragmentation persists despite clear volume-fatigue relationships and evidence thatmechanical calculations poorly predict training outcomes. We propose a thermodynamicframework that unifies these concepts by reconceptualising both as manifestations of thesame process. Drawing on non-equilibrium thermodynamics, exercise represents theuniversal biological challenge of maintaining organisational integrity whilst dissipatingenergy. Our framework introduces "performance orders" to quantify organisational challengesunder varying entropy conditions. Training volume therefore becomes the sum oforganisational challenges rather than mechanical work, whilst fatigue reflects systemicentropy across multiple temporal scales. This explains why mechanically equivalent trainingoften produces different physiological responses, why subjective difficulty measures predictoutcomes better than percentage-based programming, and why individuals can show differentrecovery requirements despite identical performance capacities. This characterises howindividuals are not just statistical noise around universal training principles, but the very basisthat determine how training mechanisms operate. We present conceptual mathematicalmodels describing entropy dynamics during exercise enabling a systems-level approach thatconnects exercise science to broader biological principles. This suggests training programmesshould focus on managing entropy generation rather than accumulating mechanical work,offering new approaches to individualised programme design