Radii and Binding Energies of Nuclei in the Alpha-Cluster Model

The alpha-cluster model is based on two assumptions that the proton-neutron pair interactions are responsible for adherence between alpha-clusters and that the NN-interaction in the alpha-clusters is isospin independent. It allows one to estimate the Coulomb energy and the short range inter-cluster bond energy in dependence on the number of clusters. The charge radii are calculated on the number of alpha-clusters too. Unlike the Weizsacker formula in this model the binding energies of alpha-clusters and excess neutrons are estimated separately. The calculated values are in a good agreement with the experimental data.Comment: Latex2e 2.09, 13 pages, 4 figure

Charge Radii of beta-Stable Nuclei

In previous work it was shown that the radius of nucleus R is determined by the alpha-cluster structure and can be estimated on the number of alpha-clusters disregarding to the number of excess neutrons. A hypothesis also was made that the radius R_m of a beta-stable isotope, which is actually measured at electron scattering experiments, is determined by the volume occupied by the matter of the core plus the volume occupied by the peripheral alpha-clusters. In this paper it is shown that the condition R_m = R restricts the number of excess neutrons filling the core to provide the beta-stability. The number of peripheral clusters can vary from 1 to 5 and the value of R for heavy nuclei almost do not change, whereas the number of excess neutrons should change with the number of peripheral clusters to get the value of R_m close to R. It can explain the path of the beta-stability and its width. The radii R_m of the stable isotopes with 12 =< Z =< 83 and the alpha-decay isotopes with 84 =< Z =< 116 that are stable to beta-decay have been calculated.Comment: Latex2e 2.09, 10 pages, 3 figure

Exploring the link between more negative osmotic potential and ryegrass summer performance

This paper outlines recent research studying within-population variation in selected New Zealand perennial ryegrass cultivars, for traits related to tolerance of summer moisture deficit. Two clonal replicates of 220 genotypes from ‘Grasslands Nui’ (Nui, n=50), ‘Grasslands Samson’ Samson, n=80), and ‘Trojan’ (n=90) were exposed to a 1 month of moisture deficit challenge, with plant water relations measurements performed to evaluate putative drought-response mechanisms. Water use of individual genotypes ranged from 1000 g water/g DM indicating large within-population variation for this trait. Mean WUE for Nui, Samson, and Trojan was, respectively, 424±16, 412±10, and 319±9 g water/g DW (P<0.001), suggesting that commercial plant breeding may have indirectly reduced water use in modern cultivars without specific focus on water relations. Principal component analysis indicated more negative osmotic potential may contribute to reduced water use while maintaining yield under water deficit, giving a potential focus for future breeding selection targeting summer water deficit tolerance.fals

Origin of the Mosaicity in Graphene Grown on Cu(111)

We use low-energy electron microscopy to investigate how graphene grows on Cu(111). Graphene islands first nucleate at substrate defects such as step bunches and impurities. A considerable fraction of these islands can be rotationally misaligned with the substrate, generating grain boundaries upon interisland impingement. New rotational boundaries are also generated as graphene grows across substrate step bunches. Thus, rougher substrates lead to higher degrees of mosaicity than do flatter substrates. Increasing the growth temperature improves crystallographic alignment. We demonstrate that graphene growth on Cu(111) is surface diffusion limited by comparing simulations of the time evolution of island shapes with experiments. Islands are dendritic with distinct lobes, but unlike the polycrystalline, four-lobed islands observed on (100)-textured Cu foils, each island can be a single crystal. Thus, epitaxial graphene on smooth, clean Cu(111) has fewer structural defects than it does on Cu(100).Comment: Article revised following reviewer comment

Unsupervised Feature Selection with Adaptive Structure Learning

The problem of feature selection has raised considerable interests in the past decade. Traditional unsupervised methods select the features which can faithfully preserve the intrinsic structures of data, where the intrinsic structures are estimated using all the input features of data. However, the estimated intrinsic structures are unreliable/inaccurate when the redundant and noisy features are not removed. Therefore, we face a dilemma here: one need the true structures of data to identify the informative features, and one need the informative features to accurately estimate the true structures of data. To address this, we propose a unified learning framework which performs structure learning and feature selection simultaneously. The structures are adaptively learned from the results of feature selection, and the informative features are reselected to preserve the refined structures of data. By leveraging the interactions between these two essential tasks, we are able to capture accurate structures and select more informative features. Experimental results on many benchmark data sets demonstrate that the proposed method outperforms many state of the art unsupervised feature selection methods

Simulation and Detection of Photonic Chern Insulators in One-Dimensional Circuit Quantum Electrodynamics Lattice

We introduce a simple method to realize and detect photonic topological Chern insulators with one-dimensional circiut quantum electrodynamics arrays. By periodically modulating the couplings of the array, we show that this one-dimensional model can be mapped into a two-dimensional Chern insulator model. In addition to allowing the study of photonic Chern insulators, this approach also provides a natural platform to realise experimentally Laughlin's pumping argument. Based on scattering theory of topological insulators and input-output formalism, we show that the photonic edge state can be probed directly and the topological invariant can be detected from the winding number of the reflection coefficient phase.Comment: 5 pages, 3 figure

A critical approach to the development of a framework to support the evaluation of information strategies in UK Higher Education Institutions

A thesis submitted for the degree of Doctor of Philosophy to the University of LutonThe objective of this thesis has been to develop a framework to support the evaluation of information strategies of UK higher education institutions (REIs). For this study the theoretical and empirical literature was extensively reviewed and four substantial pieces of empirical research were conducted. These included action research CAR), two pieces of ethnographic research, and a case study. The AR analysed problems encountered with a Student Records System at a UK university and identified both immediate and deeper causes for these problems. Ethnography I involved the researcher's participation in the information strategy development process at the same university: This included consideration of the development processes adopted and also the way that decisions were taken. Ethnography II consisted of participant observation at a range of workshops and conferences organised by the Joint Information Systems Committee on information strategy development at UK REIs. These provided a broad picture of information strategy development procedures being adopted across these HEls. The case study investigated in detail the implementation of an information strategy at a university different from that examined in AR and Ethnography I. These empirical investigations all included in-depth interviews. In total 117 people of various levels and backgrounds involved in information strategies and associated information systems within UK HEIs were interviewed. Key findings from the empirical research were: Many HErs in the process of developing an information strate!:,,),, or about to do so, were not fully sure how this should be achieved nor the extent of the likely benefits. Most HEIs implementing information strategies were using top-down directed system approaches, leaving little room for more inclusive bottom-up emergent planning. Information strategies need to be developed and evaluated using strongly human-centred methods, primarily because it became apparent that the successful functioning of such a strategy is dependent on the motivation and competencies of the people who create and use the information. Investigations into aspects of information strategy development and implementation need to focus on people's perceptions of the situation rather than seeking an objective truth independent of the participants. This reflects a Kantian perspective of knowledge. Overall, the empirical findings supported the use of a Critical Systems Thinking approach in the evaluation of information strategies at higher education institutions. The development of the evaluative framework, the main objective of the thesis, took place in two phases: developing the framework based on the literature review and revising the framework from the empirical research investigations involving a process of critical iteration. The first phase identified a range of elements associated with an HErs information strategy, and for each element highlighted the relevant theoretical andlor empirical literature that bears on the issues being addressed. In particular, the framework is strongly influenced by insights drawn from the work of three key social theorists: Kant, Habermas and Foucault. In addition, the framework includes 'guidelines for evaluation', where these are more practical questions to ask and areas to investigate when evaluating a given element ofthe strategy. The second phase took the framework through a series of reflections and revisions based on the findings from the empirical investigations. In each case, insights were gained that related to the use or applicability ofthe framework. By combining the findings from the theoretical and empirical literature with those from the empirical research, the final framework, which is believed to have filled a gap in the theoretical literature, aims to encompass the complexity of information strategy development and implementation within HEIs. The framework reflects a human-centred and Critical Systems Thinking approach, and is designed to allow potential evaluators to identify underlying causes for the success or failure of an information strategy that is implemented at an HEI