A GPU Accelerated Genetic Algorithm for the Construction of Hadamard Matrices

Hadamard matrices are square matrices with +1 and -1 entries and with columns that are mutually orthogonal. The applications include signal processing and quantum computing. There are several methods for constructing Hadamard matrices of order 2k for every positive integer k. The Hadamard conjecture proposes that there are also Hadamard matrices of order 4k for every positive integer k. We use a genetic algorithm to construct (search for) Hadamard Matrices. The initial population of random matrices is generated to have a balanced number of +1 and -1 entries in each column. Several fitness functions are implemented exploiting the basic matrix property that QTQ is diagonal if and only if the columns of matrix Q are orthogonal. The crossover process creates offspring matrix population by exchanging columns of the parent matrix population. The mutation process flips +1 and -1 entry pairs in random columns, several methods were implemented to achieve this. The use of CuPy library in Python on graphics processing units enables us to handle populations of thousands of matrices and matrix operations in parallel

SOCIOLINGUISTICS AND LINGUISTIC GEOGRAPHY

Sociolinguistics and linguistic geography should be considered as complementary rather than mutually contradictory approaches to the phenomena of language variation. Linguistic geography is a branch of historical linguistics based on samples of the stable and traditional, and necessarily somewhat biased in the selection of small communities, older informants, and traditional cultures; however, it provides a framework for interpreting studies of varied populations-in both rural and urban communities. The authors review criticisms of both linguistic geography and of sociolinguistics applications of linguistic geography, and suggest directions in which the findings of linguistic geography may be useful to sociolinguists and others in matters of interdisciplinary cooperation.http://web.ku.edu/~starjrn

A revision of the American spiders of the family Microstigmatidae (Araneae, Mygalomorphae). American Museum novitates ; no. 2707

20 p. : ill. ; 26 cm.Includes bibliographical references (p. 20)."The tribal grouping Microstigmateae Roewer is removed from the Dipluridae and elevated to familial rank. The subfamily Pseudonemesiinae Caporiacco is transferred from the Ctenizidae to the Microstigmatidae. The family is suggested to be the sister group of the Mecicobothriidae plus Hexalethidae and Dipluridae. The male of the Venezuelan species Pseudonemesia parva Caporiacco is descibed for the first time, and a new species, P. kochalkai, is described from Colombia. A genus (Ministigmata) described for a new species (M. minuta) from Brazil is hypothesized to be more closely related to the South African genus Microstigmata than to Pseudonemesia"--P. [1]

Cost and color of photosynthesis

The question of why plants are green has been revisited in several articles recently. A common theme in the discussions is to explain why photosynthesis appears to absorb less of the available green sunlight than expected. The expectation is incorrect, however, because it fails to take the energy cost of the photosynthetic apparatus into account. Depending on that cost, the red absorption band of the chlorophylls may be closely optimized to provide maximum growth power. The optimization predicts a strong influence of Fraunhofer lines in the solar irradiance on the spectral shape of the optimized absorption band, which appears to be correct. It does not predict any absorption at other wavelengths

Interacting galaxies in the IllustrisTNG simulations -- VI: Reconstructed orbits, close encounters and mergers

Cosmological simulations have been used to study interacting galaxies as a function of galaxy pair separation, enabling comparisons with observational studies of galaxy pairs. The study of interacting galaxies as a function of time (i.e. merger stage) has mostly been limited to high resolution merger simulations, due to the poor time sampling available in cosmological simulations. Building on an earlier study of galaxy pairs in the IllustrisTNG cosmological simulations, we reconstruct the orbits of galaxy pairs involving massive galaxies ($M_* > 10^{10}M_{\odot}$) at redshifts of $0 \leq z < 1$, using a novel kinematic interpolation scheme to model the orbits in between the IllustrisTNG snapshots (which are separated by 162 Myr on average). We assess the accuracy of these interpolations using a pre-existing suite of merger simulations, and find that kinematic interpolations provide a remarkable improvement in accuracy compared with interpolations that use only radial separations or 3D positions. We find that nearly 90 per cent of the closest pairs ($r < 25$ kpc) have had a pericentre encounter within the past Gyr. Many of these close pairs are found on rapidly shrinking orbits, and roughly 85 per cent of these pairs will merge within 1 Gyr. However, approximately 3 per cent of these close pairs appear to be flyby systems that will never merge. These reconstructed orbits will be used in future studies to investigate how and when galaxy properties change during close encounters and mergers between galaxies in IllustrisTNG.Comment: 15 pages, 16 figures. Accepted for publication in MNRA

An AC susceptometer for the characterization of large, bulk superconducting samples

The main purpose of this work was to design, develop and construct a simple, low-cost AC susceptometer to measure large, bulk superconducting samples (up to 32 mm in diameter) in the temperature range 78-120 K. The design incorporates a double heating system that enables a high heating rate (25 K/hour) while maintaining a small temperature gradient (< 0.2 K) across the sample. The apparatus can be calibrated precisely using a copper coil connected in series with the primary coil. The system has been used successfully to measure the temperature dependence of the AC magnetic properties of entire RE-Ba-Cu-O [(RE)BCO] bulk superconducting domains. A typical AC susceptibility measurement run from 78 K to 95 K takes about 2 hours, with excellent temperature resolution (temperature step ~ 4 mK) around the critical temperature, in particular.Comment: 25 pages, 7 figures. Accepted for publication in Measurement Science and Technolog

Improvements in reading and spelling skills after a phonological and morphological knowledge intervention in Greek children with spelling difficulties : a pilot study

In this study, we evaluated the effects of the online computer-based training program “Lexilogy-Greek” on the reading and spelling performance of young poor readers and spellers. The training is based on psycholinguistic principles that emphasize the importance of acquiring efficient phonological as well as morphological knowledge in remediating reading and spelling difficulties. Our sample consisted of fifteen 5th and 6th grade primary school children. Reading and spelling were tested at three points, with a no-intervention period and subsequently an intervention period in between these time points. We adopted a single group repeated measurement design and tested for intervention effects using repeated measures ANOVAs. The results revealed substantial treatment effects on spelling, word reading fluency and text reading fluency

Desperately seeking niches: Grassroots innovations and niche development in the community currency field

The sustainability transitions literature seeks to explain the conditions under which technological innovations can diffuse and disrupt existing socio-technical systems through the successful scaling up of experimental ‘niches’; but recent research on ‘grassroots innovations’ argues that civil society is a promising but under-researched site of innovation for sustainability, albeit one with very different characteristics to the market-based innovation normally considered in the literature. This paper aims to address that research gap by exploring the relevance of niche development theories in a civil society context. To do this, we examine a growing grassroots innovation – the international field of community currencies – which comprises a range of new socio-technical configurations of systems of exchange which have emerged from civil society over the last 30 years, intended to provide more environmentally and socially sustainable forms of money and finance. We draw on new empirical research from an international study of these initiatives comprising primary and secondary data and documentary sources, elite interviews and participant observation in the field. We describe the global diffusion of community currencies, and then conduct a niche analysis to evaluate the utility of niche theories for explaining the development of the community currency movement. We find that some niche-building processes identified in the existing literature are relevant in a grassroots context: the importance of building networks, managing expectations and the significance of external ‘landscape’ pressures, particularly at the level of national-type. However, our findings suggest that existing theories do not fully capture the complexity of this type of innovation: we find a diverse field addressing a range of societal systems (money, welfare, education, health, consumerism), and showing increasing fragmentation (as opposed to consolidation and standardisation); furthermore, there is little evidence of formalised learning taking place but this has not hampered movement growth. We conclude that grassroots innovations develop and diffuse in quite different ways to conventional innovations, and that niche theories require adaptation to the civil society context

Smart Eco-CityDevelopment in Europe and China: Opportunities, Drivers and Challenges

The policy pointers presented in this report are the result of a three-year (2015-18) research project led by Federico Caprotti at the University of Exeter. The project, Smart Eco-Cities for a Green Economy: A Comparative Analysis of Europe and China, was delivered by a research consortium comprising scholars and researchers in the UK, China, the Netherlands, France, and Germany. The aim of the project was to investigate the way in which smart city and eco-city strategies are used to enable a transition towards digital and green economies. While previous work has considered smart cities and eco-cities as separate urban development models, the project considers them together for the first time. We use the term ‘the smart eco-city’ to focus on how green targets are now included in smart city development policies and strategies. This report presents a summary of policy pointers, or ‘lessons’, learned through our work on the cities we studied in the UK, China, the Netherlands, France and Germany. Specifically, we studied, in depth, the cities of Manchester, Amsterdam, Hamburg, Bordeaux, Shanghai, Shenzhen, Ningbo and Wuhan. This work included interviews with policymakers, urban municipal authorities, tech firm executives, and grassroots and community representatives and stakeholders. Our work also included intensive and in-depth qualitative analysis of documentary sources including policy and corporate reports and other materials.The research undertaken to produce this report was supported by funding from: the Economic and Social Research Council (ESRC) through research grant ES/ L015978/1; the National Natural Science Foundation of China, project number 71461137005; the Netherlands Organisation for Scientific Research (NWO) through research grant 467-14-153 and the Dutch Academy of Sciences (KNAW) through research grant 530-6CD108; the French National Research Agency (ANR) through research grant ANR-14-02; and the German Research Foundation DFG through research grant SP 1545/1-1