Development and use of an extensometer for determining the mechanical compliance of crack toughness test specimens

Extensometer for determining mechanical compliance of crack toughness test specimen

The most massive galaxies in clusters are already fully grown at z∼0.5z \sim 0.5

By constructing scaling relations for galaxies in the massive cluster MACSJ0717.5 at $z=0.545$ and comparing with those of Coma, we model the luminosity evolution of the stellar populations and the structural evolution of the galaxies. We calculate magnitudes, surface brightnesses and effective radii using HST/ACS images and velocity dispersions using Gemini/GMOS spectra, and present a catalogue of our measurements for 17 galaxies. We also generate photometric catalogues for $\sim 3000$ galaxies from the HST imaging. With these, we construct the colour-magnitude relation, the fundamental plane, the mass-to-light versus mass relation, the mass-size relation and the mass-velocity dispersion relation for both clusters. We present a new, coherent way of modelling these scaling relations simultaneously using a simple physical model in order to infer the evolution in luminosity, size and velocity dispersion as a function of redshift, and show that the data can be fully accounted for with this model. We find that (a) the evolution in size and velocity dispersion undergone by these galaxies between $z \sim 0.5$ and $z \sim 0$ is mild, with $R_e(z) \sim (1+z)^{-0.40\pm0.32}$ and $\sigma(z) \sim (1+z)^{0.09 \pm 0.27}$, and (b) the stellar populations are old, $\sim 10$ Gyr, with a $\sim 3$ Gyr dispersion in age, and are consistent with evolving purely passively since $z \sim 0.5$ with $\Delta \log M/L_B = -0.55_{-0.07}^{+0.15} z$. The implication is that these galaxies formed their stars early and subsequently grew dissipationlessly so as to have their mass already in place by $z \sim 0.5$, and suggests a dominant role for dry mergers, which may have accelerated the growth in these high-density cluster environments.Comment: 20 pages; accepted for publication in MNRA

A photometric analysis of Abell 1689: two-dimensional multi-structure decomposition, morphological classification, and the Fundamental Plane

We present a photometric analysis of 65 galaxies in the rich cluster Abell 1689 at $z=0.183$, using the Hubble Space Telescope Advanced Camera for Surveys archive images in the rest-frame $V$-band. We perform two-dimensional multi-component photometric decomposition of each galaxy adopting different models of the surface-brightness distribution. We present an accurate morphological classification for each of the sample galaxies. For 50 early-type galaxies, we fit both a de Vaucouleurs and S\'ersic law; S0s are modelled by also including a disc component described by an exponential law. Bars of SB0s are described by the profile of a Ferrers ellipsoid. For the 15 spirals, we model a S\'ersic bulge, exponential disc, and, when required, a Ferrers bar component. We derive the Fundamental Plane by fitting 40 early-type galaxies in the sample, using different surface-brightness distributions. We find that the tightest plane is that derived by S\'ersic bulges. We find that bulges of spirals lie on the same relation. The Fundamental Plane is better defined by the bulges alone rather than the entire galaxies. Comparison with local samples shows both an offset and rotation in the Fundamental Plane of Abell 1689.Comment: 53 pages, 71 figures, MNRAS in pres

Symmetric Skyrmions

We present candidates for the global minimum energy solitons of charge one to nine in the Skyrme model, generated using sophisticated numerical algorithms. Assuming the Skyrme model accurately represents the low energy limit of QCD, these configurations correspond to the classical nuclear ground states of the light elements. The solitons found are particularly symmetric, for example, the charge seven skyrmion has icosahedral symmetry, and the shapes are shown to fit a remarkable sequence defined by a geometric energy minimization (GEM) rule. We also calculate the energies and sizes to within at least a few percent accuracy. These calculations provide the basis for a future investigation of the low energy vibrational modes of skyrmions and hence the possibility of testing the Skyrme model against experiment.Comment: latex, 9 pages, 1 figure (fig1.gif

Exact Nonperturbative Unitary Amplitudes for 1->N Transitions

I present an extension to arbitrary N of a previously proposed field theoretic model, in which unitary amplitudes for $1->8$ processes were obtained. The Born amplitude in this extension has the behavior $A(1->N)^{tree}\ =\ g^{N-1}\ N!$ expected in a bosonic field theory. Unitarity is violated when $|A(1->N)|>1$, or when $N>\N_crit\simeq e/g.$ Numerical solutions of the coupled Schr\"odinger equations shows that for weak coupling and a large range of N>\ncrit, the exact unitary amplitude is reasonably fit by a factorized expression |A(1->N)| \sim (0.73 /N) \cdot \exp{(-0.025/\g2)}. The very small size of the coefficient 1/\g2 , indicative of a very weak exponential suppression, is not in accord with standard discussions based on saddle point analysis, which give a coefficient $\sim 1.\$ The weak dependence on $N$ could have experimental implications in theories where the exponential suppression is weak (as in this model). Non-perturbative contributions to few-point correlation functions in this theory would arise at order $K\ \simeq\ \left((0.05/\g2)+ 2\ ln{N}\right)/ \ ln{(1/\g2)}$in an expansion in powers of$\g2.$Comment: 11 pages, 3 figures (not included

Does sensory relearning improve tactile function after carpal tunnel decompression? A pragmatic, assessor-blinded, randomized clinical trial

Despite surgery for carpal tunnel syndrome (CTS) being effective in 80-90% of cases, chronic numbness and hand disability can occur. The aim of this study was to investigate whether sensory relearning improves tactile discrimination and hand function after decompression. In a multi-centre, pragmatic, randomized, controlled trial, 104 patients were randomized to sensory relearning (n=52) or control (n=52) group. 93 patients completed 12 week follow-up. Primary outcome was the Shape-Texture Identification (STI) test at 6 weeks. Secondary outcomes were touch threshold, touch localisation, dexterity and self-reported hand function. No significant group differences were seen for the primary outcome (STI) at 6 weeks or 12 weeks. Similarly, no significant group differences were observed on secondary outcomes, with the exception of self-reported hand function. A secondary Complier-Averaged-CausalEffects (CACE) analysis showed no statistically significant treatment effect on the primary outcome. Sensory relearning for tactile sensory and functional deficits after carpal tunnel decompression is not effective

Theory of many-fermion systems II: The case of Coulomb interactions

In a recent paper (cond-mat/9703164) a general field-theoretical description of many-fermion systems with short-ranged interactions has been developed. Here we extend this theory to the case of disordered electrons interacting via a Coulomb potential. A detailed discussion is given of the Ward identity that controls the soft modes in the system, and the generalized nonlinear sigma model for the Coulombic case is derived and discussed.Comment: 12 pp., REVTeX, no figs, final version as publishe

Managing Projects in an Uncertain and Volatile World: Engaging Stakeholders, and Building a Systemic View of Risk

As evidenced through both a historical and contemporary number of over-runs managing projects can be a risky business. Managers are faced with effectively working with a multitude of parties, dealing with a wealth of interlocking uncertainties and frequently undertaking these activities within a compressed timeframe. This paper describes a risk management process developed to assist managers facing such situations. The process explicitly engages a range of stakeholders using a group support system and causal mapping process and provides not only a comprehensive appreciation of the risks identified but also a greater understanding of their subtleties. Using a real case the paper will describe the process and outcomes along with its implications, before reflecting on the insights, limitations and future research

Learning from mixed OR method practice: The NINES case study

Despite continued interest in the use of mixed OR/MS methods, limited attention has been paid in the literature to generic lessons that could be gained from mixing methods . in practice. Many organisational problems demand the use of a mixed method approach and thus recognising and sharing lessons could prove beneficial to both practitioners and researchers. This paper reports on an in-depth evaluation of a case study involving risk identification and quantification of the Northern Isles New Energy Solutions (NINES) project which sought to trial and plan a new energy system. The intervention involved a mixed method approach and client feedback on the efficacy of the approach was sought. The evaluation reported in this paper is carried out using a set of themes taken from the literature and seeks to highlight transferable lessons. The set of lessons that emerge are presented along with their implications for both general OR modelling practice and the specific situation of mixing OR/MS methods. The paper concludes by discussing the implications of the work and directions for future work which will be of interest to both practitioners and researchers interested in mixed method OR/MS work

Association of psychological distress, quality of life and costs with carpal tunnel syndrome severity: a crosssectional analysis of the PALMS cohort

Objectives: The PALMS study is designed to identify prognostic factors for outcome from corticosteroid injection and surgical decompression for carpal tunnel syndrome (CTS) and predictors of cost over 2 years. The aim of this paper is to explore the cross-sectional association of baseline patient-reported and clinical severity with anxiety, depression, health-related quality of life and costs of CTS in patients referred to secondary care. Methods: Prospective, multi-centre cohort study initiated in 2013. We collected baseline data on patientreported symptom severity (CTS-6), psychological status (HADS), hand function (Michigan Hand Questionnaire) comorbidities, EQ5D-3L and sociodemographic variables. Nerve conduction tests classified patients into five severity grades (mild to very severe). Data were analysed using a general linear model. Results: 753 patients with CTS provided complete baseline data. Multivariable linear regression adjusting for age, sex, ethnicity, duration of CTS, smoking status, alcohol consumption, employment status, body mass index and comorbidities showed a highly statistically significant relationship between CTS-6 and anxiety, depression and the EQ-5D (p<0.0001 in each case). Likewise, a significant relationship was observed between electrodiagnostic severity and anxiety (p=0.027) but not with depression (p=0.986) or the EQ-5D (p=0.257). NHS and societal costs in the 3 months prior to enrolment were significantly associated with self-reported severity (p<0.0001) but not with electrodiagnostic severity. Conclusions: Patient-reported symptom severity in carpal tunnel syndrome is significantly and positively associated with anxiety, depression, health-related quality of life and NHS and societal costs even when adjusting for age, gender, body mass index, comorbidities, smoking, drinking and occupational status. In contrast there is little or no evidence of any relationship with objectively derived CTS severity. Future research is needed to understand the impact of approaches and treatments that address psychosocial stressors as well as biomedical factors on relief of symptoms from carpal tunnel syndrome.CJH was funded by the National Institute for Health Research (NIHR) through a NIHR Senior Research Fellowship. ECFW is funded by the NIHR Cambridge Biomedical Research Centre