Exploring the phase structure of lattice QCD with twisted mass quarks

The phase structure of zero temperature twisted mass lattice QCD is investigated. We find strong metastabilities in the plaquette observable when the untwisted quark mass sweeps across zero.Comment: Talks presented at Lattice2004(spectrum), 6 pages, 6 figure

The phase structure of lattice QCD with two flavours of Wilson quarks and renormalization group improved gluons

The effect of changing the lattice action for the gluon field on the recently observed [1] first order phase transition near zero quark mass is investigated by replacing the Wilson plaquette action by the DBW2 action. The lattice action for quarks is unchanged: it is in both cases the original Wilson action. It turns out that Wilson fermions with the DBW2 gauge action have a phase structure where the minimal pion mass and the jump of the average plaquette are decreased, when compared to Wilson fermions with Wilson plaquette action at similar values of the lattice spacing. Taking the DBW2 gauge action is advantageous also from the point of view of the computational costs of numerical simulations.Comment: 34 pages, 3 tables, 14 figures; revised version to appear in EPJ

The geomorphological setting of some of Scotland's east coast freshwater mills: a comment on Downward and Skinner (2005) ‘Working rivers: the geomorphological legacy...’

Many of the water mills on Scotland's east coast streams, unlike those discussed recently by Downward and Skinner (2005 Area 37 138–47), are found in predominantly bedrock reaches immediately downstream of knickpoints (i.e. bedrock steps). Bedrock knickpoints in the lower reaches of Scottish rivers are a widespread fluvial response to the glacio-isostatic rebound of northern Britain. These steps in the river profile propagate headward over time, but for intervals of a few centuries or so they are sufficiently stable to be exploited for the elevational fall necessary to power the mill wheel. Many of these mills were apparently powered by ‘run-of-the-river’, as are some today that formerly had mill dams. The typical lack of sediment storage along the erosional lower reaches of many Scottish rivers means that failure of mill structures in Scotland will probably have less dramatic geomorphological and management implications than those suggested by Downward and Skinner for southern English rivers

Derivative based global sensitivity measures

The method of derivative based global sensitivity measures (DGSM) has recently become popular among practitioners. It has a strong link with the Morris screening method and Sobol' sensitivity indices and has several advantages over them. DGSM are very easy to implement and evaluate numerically. The computational time required for numerical evaluation of DGSM is generally much lower than that for estimation of Sobol' sensitivity indices. This paper presents a survey of recent advances in DGSM concerning lower and upper bounds on the values of Sobol' total sensitivity indices $S\_{i}^{tot}$. Using these bounds it is possible in most cases to get a good practical estimation of the values of $S\_{i}^{tot}$. Several examples are used to illustrate an application of DGSM

Twisted mass fermions: neutral pion masses from disconnected contributions

Twisted mass fermions allow light quarks to be explored but with the consequence that there are mass splittings, such as between the neutral and charged pion. Using a direct calculation of the connected neutral pion correlator and stochastic methods to evaluate the disconnected correlations, we determine the neutral pion mass. We explore the dependence on lattice spacing and quark mass in quenched QCD. For dynamical QCD, we determine the sign of the splitting which is linked, via chiral PT, to the nature of the phase transition at small quark mass.Comment: 6 pages, poster (hadron spectrum and quark masses) at Lattice 2005,Dublin, July 25-3

Involving users in OPAC interface design: Perspective from a UK study

This is the post-print versoin of the Article. The official published version can be accessed from the link below - Copyright @ 2007 SpringerThe purpose of this study was to determine user suggestions for a typical OPAC (Online Public Library Catalogue) application’s functionality and features. An experiment was undertaken to find out the type of interactions features that users prefer to have in an OPAC. The study revealed that regardless of users’ Information Technology (IT) backgrounds, their functionality expectations of OPACs are the same. However, based on users’ previous experiences with OPACs, their requirements with respect to specific features may change. Users should be involved early in the OPAC development cycle process in order to ensure usable and functional interface

Improvement of quality of life in patients with concomitant allergic asthma and atopic dermatitis: one year follow-up of omalizumab therapy

<p>Abstract</p> <p>Objective</p> <p>Anti IgE treatment with omalizumab is efficacious in the treatment of patients suffering from allergic asthma, improving asthma control and improving quality of life. Furthermore, this approach could be beneficial for patients with concomitant atopic dermatitis. We assessed quality of life and asthma control in atopic patients with allergic asthma and concomitant atopic dermatitis versus those with asthma and without atopic dermatitis treated with omalizumab.</p> <p>Methods</p> <p>A total of 22 patients with severe allergic asthma were treated with omalizumab for 12 months. 13 patients with allergic asthma without concomitant atopic dermatitis (IgE 212 ± 224 IU/ml) and 9 patients with concomitant allergic asthma and atopic dermatitis (IgE 3,528 ± 2,723 IU/ml) were included. Asthma-related quality of life (AQLQ), atopic dermatitis related quality of life (DLQI), and asthma-related treatment were compared between both groups at baseline and after initiating omalizumab treatment.</p> <p>Results</p> <p>DLQI was significantly in favor of omalizumab after 2 months in the atopic dermatitis/asthma group (P = 0.01); AQLQ was improved after 6 months in the asthma group (P = 0.01), while no change was seen in AQLQ in the atopic dermatitis/asthma group (P = 0.12). Omalizumab controlled oral corticosteroid use more effective (P < 0.01) in patients with asthma and atopic dermatitis (in 9/9 cases) compared to patients with asthma alone (9/13). Baseline IgE as well as other factors do not predict response to omalizumab.</p> <p>Conclusions</p> <p>Omalizumab is effective in improving atopic dermatitis-related quality of life scores and modulates oral corticosteroid use in patients with concomitant asthma and atopic dermatitis in a positive fashion.</p