CAD and creativity: does the computer really help?

We are frequently told by its exponents that computeraided design (CAD) liberates designers and gives them new ways of envisioning their work, but is this really true? CAD in architecture is examined to see to what extent it has enhanced creativity in design. This is partly done by applying a test of creativity advanced by contemporary architect Herman Hertzberger. In this analysis, CAD is found somewhat wanting, and some suggestions are made as to why this might be so

Comparative evaluation of parametric design systems for teaching design computation

Three parametric design systems were tested by the authors to assess their suitability for undergraduate teaching. We used criteria taken from the ‘cognitive dimensions’ literature and an exercise of typical geometric operations in ascending order of complexity. For each system the cognitive barriers associated with the sequence of operations were plotted to create a ‘learning curve’. Different parametric systems presented distinctly different learning curves. The test exercise had to be completed in its entirety to assess the potential challenges which students with different educational levels, skills and abilities might encounter, so a single expert user conducted the tests. This research is intended to develop methods, both design exercises and evaluative criteria that could be used in future empirical studies

The Objective Assessment of Cough Frequency in Bronchiectasis.

INTRODUCTION: Cough in bronchiectasis is associated with significant impairment in health status. This study aimed to quantify cough frequency objectively with a cough monitor and investigate its relationship with health status. A secondary aim was to identify clinical predictors of cough frequency. METHODS: Fifty-four patients with bronchiectasis were compared with thirty-five healthy controls. Objective 24-h cough, health status (cough-specific: Leicester Cough Questionnaire LCQ and bronchiectasis specific: Bronchiectasis Health Questionnaire BHQ), cough severity and lung function were measured. The clinical predictors of cough frequency in bronchiectasis were determined in a multivariate analysis. RESULTS: Objective cough frequency was significantly raised in patients with bronchiectasis compared to healthy controls [geometric mean (standard deviation)] 184.5 (4.0) vs. 20.6 (3.2) coughs/24-h; mean fold-difference (95% confidence interval) 8.9 (5.2, 15.2); p < 0.001 and they had impaired health status. There was a significant correlation between objective cough frequency and subjective measures; LCQ r = -0.52 and BHQ r = -0.62, both p < 0.001. Sputum production, exacerbations (between past 2 weeks to 12 months) and age were significantly associated with objective cough frequency in multivariate analysis, explaining 52% of the variance (p < 0.001). There was no statistically significant association between cough frequency and lung function. CONCLUSIONS: Cough is a common and significant symptom in patients with bronchiectasis. Sputum production, exacerbations and age, but not lung function, were independent predictors of cough frequency. Ambulatory objective cough monitoring provides novel insights and should be further investigated as an outcome measure in bronchiectasis

Biomorpher: interactive evolution for parametric design

Combining graph-based parametric design with metaheuristic solvers has to date focussed solely on performance based criteria and solving clearly defined objectives. In this paper, we outline a new method for combining a parametric modelling environment with an interactive Cluster-Orientated Genetic Algorithm (COGA). In addition to performance criteria, evolutionary design exploration can be guided through choice alone, with user motivation that cannot be easily defined. As well as numeric parameters forming a genotype, the evolution of whole parametric definitions is discussed through the use of genetic programming. Visualisation techniques that enable mixing small populations for interactive evolution with large populations for performance-based optimisation are discussed, with examples from both academia and industry showing a wide range of applications

Multiple dimensions of health locus of control in a representative population sample: ordinal factor analysis and cross-validation of an existing three and a new four factor model

<p>Abstract</p> <p>Background</p> <p>Based on the general approach of locus of control, health locus of control (HLOC) concerns control-beliefs due to illness, sickness and health. HLOC research results provide an improved understanding of health related behaviour and patients' compliance in medical care. HLOC research distinguishes between beliefs due to Internality, Externality powerful Others (POs) and Externality Chance. However, evidences for differentiating the POs dimension were found. Previous factor analyses used selected and predominantly clinical samples, while non-clinical studies are rare. The present study is the first analysis of the HLOC structure based on a large representative general population sample providing important information for non-clinical research and public health care.</p> <p>Methods</p> <p>The standardised German questionnaire which assesses HLOC was used in a representative adult general population sample for a region in Northern Germany (N = 4,075). Data analyses used ordinal factor analyses in LISREL and Mplus. Alternative theory-driven models with one to four latent variables were compared using confirmatory factor analysis. Fit indices, chi-square difference tests, residuals and factor loadings were considered for model comparison. Exploratory factor analysis was used for further model development. Results were cross-validated splitting the total sample randomly and using the cross-validation index.</p> <p>Results</p> <p>A model with four latent variables (Internality, Formal Help, Informal Help and Chance) best represented the HLOC construct (three-dimensional model: normed chi-square = 9.55; RMSEA = 0.066; CFI = 0.931; SRMR = 0.075; four-dimensional model: normed chi-square = 8.65; RMSEA = 0.062; CFI = 0.940; SRMR = 0.071; chi-square difference test: p < 0.001). After excluding one item, the superiority of the four- over the three-dimensional HLOC construct became very obvious (three-dimensional model: normed chi-square = 7.74; RMSEA = 0.059; CFI = 0.950; SRMR = 0.079; four-dimensional model: normed chi-square = 5.75; RMSEA = 0.049; CFI = 0.965; SRMR = 0.065; chi-square difference test: p < 0.001). Results were confirmed by cross-validation. Results based on our large community sample indicated that western general populations separate health-related control-beliefs concerning formal and informal assistance.</p> <p>Conclusions</p> <p>Future non-clinical HLOC studies in western cultures should consider four dimensions of HLOC: Internality, Formal Help, Informal Help and Chance. However, the standardised German instrument needs modification. Therefore, confirmation of our results may be useful. Future research should compare HLOC structure between clinical and non-clinical samples as well as cross-culturally.</p

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

The motion of an ion in an electron gas

We give a semi-classical treatment of the problem of electrical conduction around a charged impurity ion in a metal. As the electrons flow past the ion they are scattered by its screened Coulomb potential and so introduce a velocity dependent distribution of charge. This charge distribution leads, through the Poisson equation, to a modification of the potential surrounding the ion through which the electrons are initially scattered; we look for a self-consistent or simultaneous solution to the Boltzmann and Poisson equations. This final velocity dependent charge distribution induces an electric field at the ion, so exerting a force on that ion. We identify two effects: (i) a screening force acting so as to reduce the effect of the external field on the ion, (ii) a drift force resulting from the direct collisions between electron, and ion. The process is described by a Boltzmann Transport equation which we solve at large distances from the ion. We derive the Green's Function for the equivalent integral equation, and then solve that equation by means of a Fourier Transform. In this technique we do not assume as in previous approaches that the ion is stationary or that its charge is small. The evaluation of the Green's Function does however involve the construction of an orbit model in which all scattered electrons pass through the ion itself and we do not expect this model to be of any use inside the screening radius. We turn to a method of expansion by spherical harmonics, suggested by Das in his thesis, in the hope that it may be of use at short range. In understanding a paradox of the method we lose a criterion for convergence and our confidence in the method. To do this we consider the electron mean free path to be infinite in this short range region. In this limit a quantum mechanical calculation of the self-consistent field gives a result identical to that from a classical weak charge calculation due to Peierls, in the same limit, with the significant addition of a cut-off in momentum space at twice the Fermi-momentum. It is this cut-off, for which Peierls had argued on physical grounds, that eliminates a divergence at the origin. We use it to calculate the force. We find that we may add Peierls' result where the Green's Function method is too insensitive. There are then three extra terms in the force, two due to drift and one to screening. However, the term we interpret as a screening correction may for large enough charge on the ion become greater than the direct field force. This may be due to an error in our interpretation as screening, or in the calculation itself. If it is the latter we propose a further calculation to check. In as far as the force on the ion derived in this thesis may be larger than the direct field force there is no disagreement with experimental data. Until we can understand the screening problem the result is not suitable for a detailed comparison with experiment.</p