Quasimodes of a chaotic elastic cavity with increasing local losses

We report non-invasive measurements of the complex field of elastic quasimodes of a silicon wafer with chaotic shape. The amplitude and phase spatial distribution of the flexural modes are directly obtained by Fourier transform of time measurements. We investigate the crossover from real mode to complex-valued quasimode, when absorption is progressively increased on one edge of the wafer. The complexness parameter, which characterizes the degree to which a resonance state is complex-valued, is measured for non-overlapping resonances and is found to be proportional to the non-homogeneous contribution to the line broadening of the resonance. A simple two-level model based on the effective Hamiltonian formalism supports our experimental results

Performance of a GridPix detector based on the Timepix3 chip

A GridPix readout for a TPC based on the Timepix3 chip is developed for future applications at a linear collider. The GridPix detector consists of a gaseous drift volume read out by a single Timepix3 chip with an integrated amplification grid. Its performance is studied in a test beam with 2.5 GeV electrons. The GridPix detector detects single ionization electrons with high efficiency. The Timepix3 chip allowed for high sample rates and time walk corrections. Diffusion is found to be the dominating error on the track position measurement both in the pixel plane and in the drift direction, and systematic distortions in the pixel plane are below 10 $\mu$m. Using a truncated sum, an energy loss (dE/dx) resolution of 4.1% is found for an effective track length of 1 m.Comment: To be published in Nuclear Instruments and Methods in Physics Research Section

Actions of metformin and statins on lipid and glucose metabolism and possible benefit of combination therapy

Patients with diabetes type 2 have an increased risk for cardiovascular disease and commonly use combination therapy consisting of the anti-diabetic drug metformin and a cholesterol-lowering statin. However, both drugs act on glucose and lipid metabolism which could lead to adverse effects when used in combination as compared to monotherapy. In this review, the proposed molecular mechanisms of action of statin and metformin therapy in patients with diabetes and dyslipidemia are critically assessed, and a hypothesis for mechanisms underlying interactions between these drugs in combination therapy is developed

High practice variation in risk stratification, baseline oncological staging, and follow-up strategies for T1 colorectal cancers in the Netherlands

Background and study aims Based on pathology, locally resected T1 colorectal cancer (T1-CRC) can be classified as having low- or high-risk for irradicality and/or lymph node metastasis, the latter requiring adjuvant surgery. Reporting and application of pathological high-risk criteria is likely variable, with inherited variation regarding baseline oncological staging, treatment and surveillance. Methods We assessed practice variation using an online survey among gastroenterologists and surgeons participating in the Dutch T1-CRC Working Group. Results Of the 130 invited physicians, 53 % participated. Regardi

Experimental determination of the quasi-particle decay length ξSm\xi_{\text{Sm}} in a superconducting quantum well

We have investigated experimentally the electronic transport properties of a two-dimensional electron gas (2DEG) present in an AlSb/InAs/AlSb quantum well, where part of the toplayer has been replaced by a superconducting Nb strip, with an energy gap $\Delta_0$. By measuring the lateral electronic transport underneath the superconductor, and comparing the experimental results with a model based on the Bogoliubov-de Gennes equation and the Landauer-B\"uttiker formalism, we obtain a decay length $\xi_{\text{Sm}} \approx 100~\text{nm}$ for electrons. This decay length corresponds to an interface transparency $T_{\text{SIN}}=0.7$ between the Nb and InAs. Using this value, we infer an energy gap in the excitation spectrum of the SQW of $\Delta_{\text{eff}} = 0.97 \Delta_0 = 0.83~\text{meV}$.Comment: Revtex, 3 PostScript figure

Short Musculoskeletal Function Assessment:normative data of the Dutch population

The Short Musculoskeletal Function Assessment (SMFA) is widely used in both research and clinical practice. Despite its frequent use, normative data of the SMFA have remained limited. Aim of this study was to gather normative data for the Dutch SMFA (SMFA-NL). The SMFA-NL consists of two indices (function index and bother index) and four subscales (upper extremity dysfunction, lower extremity dysfunction, mental and emotional problems, and problems with daily activities). A total of 900 patients were invited to fill in the SMFA-NL. Six age groups (18-24, 25-34, 35-44, 45-54, 55-64, and 65-75 years) were constructed. Analysis of variance, t tests, and regression analyses were used to assess age and gender effects. The response rate was 97 %. There was a significant difference between men and women in scores on all indices and subscales (range p <0.001 to p = 0.002), except for the upper extremity dysfunction subscale (p = 0.06). A significant interaction effect was found between gender and age for the upper extremity dysfunction subscale; a larger decrease in score with increasing age was observed for women, compared with men. Significant differences were found between age groups for the bother index (p <0.001), lower extremity dysfunction subscale (p = 0.001), and the problems with daily activities subscale (p = 0.002). Significant differences in SMFA-NL scores were found between men and women and between different age groups. These SMFA-NL normative data provide an opportunity of benchmarking health status of participants with musculoskeletal disorders or injuries against their age- and gender-matched peers in the Dutch population

Nilpotent orbits and codimension-two defects of 6d N=(2,0) theories

We study the local properties of a class of codimension-2 defects of the 6d N=(2,0) theories of type J=A,D,E labeled by nilpotent orbits of a Lie algebra \mathfrak{g}, where \mathfrak{g} is determined by J and the outer-automorphism twist around the defect. This class is a natural generalisation of the defects of the 6d theory of type SU(N) labeled by a Young diagram with N boxes. For any of these defects, we determine its contribution to the dimension of the Higgs branch, to the Coulomb branch operators and their scaling dimensions, to the 4d central charges a and c, and to the flavour central charge k.Comment: 57 pages, LaTeX2

Corrigendum: Short-lived positron emitters in beam-on PET imaging during proton therapy (2015 Phys. Med. Biol. 60 8923)

Because of strong indications of multiple counting by the multi-channel scaler (MCS) during most of the experiments described in Dendooven et al (2015 Phys. Med. Biol. 60 8923–47), the production of short-lived positron emitters in the stopping of 55 MeV protons in water, carbon, phosphorus and calcium was remeasured. The new results are reported here. With proper single counting of the MCS, the new production rates are 1.1 to 2.9 times smaller than reported in Dendooven et al (2015 Phys. Med. Biol. 60 8923–47). The omission of the conversion from MCS time bin to time unit in the previous data analysis was corrected, leading to an increase of the production rate by a factor of 2.5 or 10 for some nuclides. The most copiously produced short-lived nuclides and their production rates relative to the relevant long-lived nuclides are: 12N (T 1/2  =  11 ms) on carbon (5.3% of 11C), 29P (T 1/2  =  4.1 s) on phosphorus (23% of 30P) and 38mK (T 1/2  =  0.92 s) on calcium (173% of 38gK). The number of decays integrated from the start of an irradiation as a function of time during the irradiation of PMMA and 4 tissue materials has been determined. For (carbon-rich) adipose tissue, 12N dominates up to 70 s. On bone tissue, 38mK dominates the beam-on PET counts from 0.2–0.7 s until about 80–110 s. Considering nuclides created on phosphorus and calcium, the short-lived ones provide 8 times more decays than the long-lived ones during a 70 s irradiation. Bone tissue will thus be much better visible in beam-on PET compared to PET imaging after an irradiation. From the estimated number of 12N PET counts, we conclude that, for any tissue, except carbon-poor ones, 12N PET imaging potentially provides equal quality proton range information as prompt gamma imaging with an optimized knife-edge slit camera

Crystalline Assemblies and Densest Packings of a Family of Truncated Tetrahedra and the Role of Directional Entropic Forces

Polyhedra and their arrangements have intrigued humankind since the ancient Greeks and are today important motifs in condensed matter, with application to many classes of liquids and solids. Yet, little is known about the thermodynamically stable phases of polyhedrally-shaped building blocks, such as faceted nanoparticles and colloids. Although hard particles are known to organize due to entropy alone, and some unusual phases are reported in the literature, the role of entropic forces in connection with polyhedral shape is not well understood. Here, we study thermodynamic self-assembly of a family of truncated tetrahedra and report several atomic crystal isostructures, including diamond, {\beta}-tin, and high- pressure lithium, as the polyhedron shape varies from tetrahedral to octahedral. We compare our findings with the densest packings of the truncated tetrahedron family obtained by numerical compression and report a new space filling polyhedron, which has been overlooked in previous searches. Interestingly, the self-assembled structures differ from the densest packings. We show that the self-assembled crystal structures can be understood as a tendency for polyhedra to maximize face-to-face alignment, which can be generalized as directional entropic forces.Comment: Article + supplementary information. 23 pages, 10 figures, 2 table

Oxygen Moment Formation and Canting in Li2CuO2

The possibilities of oxygen moment formation and canting in the quasi-1D cuprate Li2CuO2 are investigated using single crystal neutron diffraction at 2 K. The observed magnetic intensities could not be explained without the inclusion of a large ordered oxygen moment of 0.11(1) Bohr magnetons. Least-squares refinement of the magnetic structure of Li2CuO2 in combination with a spin-density Patterson analysis shows that the magnetization densities of the Cu and O atoms are highly aspherical, forming quasi-1D ribbons of localised Cu and O moments. Magnetic structure refinements and low-field magnetization measurements both suggest that the magnetic structure of Li2CuO2 at 2 K may be canted. A possible model for the canted configuration is proposed.Comment: 10 pages, 8 figures (screen resolution