GEANT4 Target Simulations for Low Energy Medical Applications

The GEANT4 code offers an extensive set of hadronic models for various projectiles and energy ranges. These models include theoretical, parameterized and, for low energy neutrons, data driven models. Theoretical or semi-empirical models sometimes cannot reproduce experimental data at low energies(<100MeV), especially for low Z elements, and therefore recent GEANT4 developments included a new particle\hp package which uses evaluated nuclear databases for proton interactions below 200 MeV. These recent developments have been used to study target designs for low energy proton accelerators, as replacements of research reactors, for medical applications. Presented in this paper are results of benchmarking of these new models for a range of targets, from lithium neutron production targets to molybdenum isotope production targets, with experimental data. Also included is a discussion of the most promising target designs that have currently been studied

Restorative practice and behaviour management in schools: discipline meets care.

The history of restorative practices in New Zealand schools is directly related to projects such as the Suspension Reduction Initiative (SRI) and the more recent Student Engagement Initiative (SEI); thus the origins of restorative practices in schools are linked with behaviour management and school discipline. During the same period, teachers' work has become more complex: They are working with an increasingly diverse range of students, which in turn requires epistemologically diverse teaching and relationship-building approaches to ensure maximum participation for all. Teachers are looking for new and better ways to interact with students in their classrooms, and those responsible for disciplinary systems are looking to restorative practice for new ways to resolve the increasing range and number of difficulties between teachers and students, students and other students, and between the school and parents. Restorative practices (RP) are currently seen as a way of achieving all this, so they carry a huge burden of hope. Relationship skills are a key competency in the new curriculum, and the philosophy of restoration offers both a basis for understanding and a process for putting this agenda into practice. In effect, it means educating for citizenship in a diverse world, including teaching the skills of conflict resolution. If we accept this philosophy, the curriculum for teacher education will require significant changes in what students are taught about behaviour and classroom management

Letter: Faecal volatile organic metabolites, promising biomarkers in inflammatory bowel disease and Letter: Faecal volatile organic metabolites as novel diagnostic biomarkers in inflammatory bowel disease. Authors' reply

The aetiology of inflammatory bowel disease (IBD) remains poorly understood. Recent evidence suggests an important role of gut microbial dysbiosis in IBD, and this may be associated with changes in faecal volatile organic metabolites (VOMs).To describe the changes in the faecal VOMs of patients with IBD and establish their diagnostic potential as non-invasive biomarkers.Faecal samples were obtained from 117 people with Crohn's disease (CD), 100 with ulcerative colitis (UC), and 109 healthy controls. Faecal VOMs were extracted using solid-phase micro-extraction and analysed by gas chromatography mass spectrometry. Data analysis was carried out using partial least squares-discriminate analysis (PLS-DA) to determine class membership based on distinct metabolomic profiles.The PLS-DA model showed clear separation of active CD from inactive disease and healthy controls (P < 0.001). Heptanal, 1-octen-3-ol, 2-piperidinone and 6-methyl-2-heptanone were up-regulated in the active CD group [variable important in projection (VIP) score 2.8, 2.7, 2.6 and 2.4, respectively], while methanethiol, 3-methyl-phenol, short-chain fatty acids and ester derivatives were found to be less abundant (VIP score of 3.5, 2.6, 1.5 and 1.2, respectively). The PLS-DA model also separated patients with small bowel CD from healthy controls and those with colonic CD from UC (P < 0.001). In contrast, less distinct separation was observed between active UC, inactive UC and healthy controls.Analysis of faecal volatile organic metabolites can provide an understanding of gut metabolomic changes in IBD. It has the potential to provide a non-invasive means of diagnosing IBD, and can differentiate between UC and CD

Pattern of physical activity can influence its efficacy on muscle and bone health in middle-aged men and women

Purpose This study aimed at investigating whether association between physical activity, and bone density and muscle strength depends on daily activity pattern.Methods Loading dose of moderate-to-vigorous physical activity (MVPA) was measured using accelerometer on 54 men (Mage = 54.1 years) and 59 women (Mage = 52.1 years). Pattern of MVPA was quantiied as number and length of MVPA bouts, and the length of break bouts between MVPA bouts. Knee extension torque (KET) and broadband ultrasound attenu-ation (BUA) of the calcaneus were also measured. Regression analysis was employed to examine the moderation efect of MVPA pattern.Results Loading dose had a larger efect on BUA (b = .002, p = .035) and KET (b = .004, p = .01) with the increase of median length of MVPA bout, but had a smaller efect on KET with the increase of maximal length of break bout (b = − .015, p = .024).Conclusions This study suggests that pattern of physical activity can inluence its eicacy on muscle and bone health

Flux-Balance Modeling of Plant Metabolism

Flux-balance modeling of plant metabolic networks provides an important complement to 13C-based metabolic flux analysis. Flux-balance modeling is a constraints-based approach in which steady-state fluxes in a metabolic network are predicted by using optimization algorithms within an experimentally bounded solution space. In the last 2 years several flux-balance models of plant metabolism have been published including genome-scale models of Arabidopsis metabolism. In this review we consider what has been learnt from these models. In addition, we consider the limitations of flux-balance modeling and identify the main challenges to generating improved and more detailed models of plant metabolism at tissue- and cell-specific scales. Finally we discuss the types of question that flux-balance modeling is well suited to address and its potential role in metabolic engineering and crop improvement

‘Ethnic group’, the state and the politics of representation

The assertion, even if only by implication, that ‘ethnic group’ categories represent ‘real’ tangible entities, indeed identities, is commonplace not only in the realms of political and policy discourse but also amongst contemporary social scientists. This paper, following Brubaker (2002), questions this position in a number of key respects: of these three issues will dominate the discussion that follows. First, there is an interrogation of the proposition that those to whom the categories/labels refer constitute sociologically meaningful ‘groups’ as distinct from (mere) human collectivities. Secondly, there is the question of how these categories emerge, i.e. exactly what series of events, negotiations and contestations lie behind their construction and social acceptance. Thirdly, and as a corollary to the latter point, we explore the process of reification that leads to these categories being seen to represent ‘real things in the world’ (ibid.)

Commensurability classes of hyperbolic Coxeter groups

AbstractIn this paper, we classify all the hyperbolic Coxeter n-simplex reflection groups up to wide-commensurability for all n⩾3. We also determine all the subgroup relationships among the groups

Determination of the Kobayashi-Maskawa-Cabibbo matrix element V_{us} under various flavor-symmetry-breaking models in hyperon semileptonic decays

We study the success to describe hyperon semileptonic decays of four models that incorporate second-order SU(3) symmetry breaking corrections. The criteria to assess their success is by determining V_{us} in each of the three relevant hyperon semileptonic decays and comparing the values obtained with one another and also with the one that comes from K_{l3} decays. A strong dependence on the particular symmetry breaking model is observed. Values of V_{us} which do not agree with the one of K_{l3} are generally obtained. However, in the context of chiral perturbation theory, only the model whose corrections are O(m_s) and O(m_s^{3/2}) is successful. Using its predictions for the f_1 form factors one can quote a value of V_{us} from this model, namely, V_{us}=0.2176\pm 0.0026, which is in excellent agreement with the K_{l3} one.Comment: Final versio