Design reuse research : a computational perspective

This paper gives an overview of some computer based systems that focus on supporting engineering design reuse. Design reuse is considered here to reflect the utilisation of any knowledge gained from a design activity and not just past designs of artefacts. A design reuse process model, containing three main processes and six knowledge components, is used as a basis to identify the main areas of contribution from the systems. From this it can be concluded that while reuse libraries and design by reuse has received most attention, design for reuse, domain exploration and five of the other knowledge components lack research effort

Invasions, DNA barcodes, and rapid biodiversity assessment using ants of Mauritius

<p>Abstract</p> <p>Background</p> <p>Using an understudied taxon (Hymenoptera, Formicidae) found on a tropical island (Mauritius) where native flora and fauna have been threatened by 400 years of habitat modification and introduced species, we tested whether estimated incidences of diversity and complementarity were similar when measured by standard morphological alpha-taxonomy or phylogenetic diversity (PD) based on a standardized mitochondrial barcode and corroborating nuclear marker.</p> <p>Results</p> <p>We found that costs related to site loss (considered loss of evolutionary history measured as loss of barcode PD) were not significantly different from predictions made either a) using standard morphology-based taxonomy, or b) measured using a nuclear marker. Integrating morphology and barcode results permitted us to identify a case of initially morphologically-cryptic variation as a new and endemic candidate species. However, barcode estimates of the relative importance of each site or network of sites were dramatically affected when the species in question was known to be indigenous or introduced.</p> <p>Conclusion</p> <p>This study goes beyond a mere demonstration of the rapid gains possible for diversity assessment using a standardized DNA barcode. Contextualization of these gains with ecological and natural history information is necessary to calibrate this wealth of standardized information. Without such an integrative approach, critical opportunities to advance knowledge will be missed.</p

A New Species of the Genus Scybalocanthon (Coleoptera: Scarabaeinae) from Southeast Brazil

A new species of the genus Scybalocanthon Martínez 1948, Scybalocanthon korasakiae sp. nov., from Atlantic forest ecosystem, state of Minas Gerais, Brazil is described based on external and genital morphology

Maternal thyroid function and child educational attainment: prospective cohort study

Objective: To determine if first trimester maternal thyroid dysfunction is a critical determinant of child scholastic performance and overall educational attainment. Design: Prospective cohort study. Setting: Avon Longitudinal Study of Parents and Children cohort in the UK. Participants: 4615 mother-child pairs with an available first trimester sample (median 10 weeks gestation, interquartile range 8-12). Exposures: Free thyroxine, thyroid stimulating hormone, and thyroid peroxidase antibodies assessed as continuous measures and the seven clinical categories of maternal thyroid function. Main outcome measures: Five age-specific national curriculum assessments in 3580 children at entry stage assessment at 54 months, increasing up to 4461 children at their final school assessment at age 15. Results: No strong evidence of clinically meaningful associations of first trimester free thyroxine and thyroid stimulating hormone levels with entry stage assessment score or Standard Assessment Test scores at any of the key stages was found. Associations of maternal free thyroxine or thyroid stimulating hormone with the total number of General Certificates of Secondary Education (GCSEs) passed (range 0-16) were all close to the null: free thyroxine, rate ratio per pmol/L 1.00 (95% confidence interval 1.00 to 1.01); and thyroid stimulating hormone, rate ratio 0.98 (0.94 to 1.02). No important relationship was observed when more detailed capped scores of GCSEs allowing for both the number and grade of pass or when language, mathematics, and science performance were examined individually or when all educational assessments undertaken by an individual from school entry to leaving were considered. 200 (4.3%) mothers were newly identified as having hypothyroidism or subclinical hypothyroidism and 97 (2.1%) subclinical hyperthyroidism or hyperthyroidism. Children of mothers with thyroid dysfunction attained an equivalent number of GCSEs and equivalent grades as children of mothers with euthyroidism. Conclusions: Maternal thyroid dysfunction in early pregnancy does not have a clinically important association with impaired child performance at school or educational achievement

RF-mobility gain: Concept, measurement campaign, and exploitation

Self-directed movement of radio devices can enable large amounts of power gain since the sources of fluctuations in received signal power due to multipath-induced small-scale fading have highly localized effects. We call the gain achieved by finding a better location the mobility gain. University of Pennsylvania Experimental data for indoor as well as outdoor measurement studies are used to illustrate the potential of this RF-Mobility Gain concept over a wide range of frequencies. An analysis of the RF data reveals that a small amount of energy spent on searching for a better location can pay large dividends in long-term power expenditures for RF transmission. Challenges in building such a system for peer-to-peer links and network applications are discussed along with potential coordination algorithms

Room-temperature exciton-polaritons with two-dimensional WS2

Two-dimensional transition metal dichalcogenides exhibit strong optical transitions with significant potential for optoelectronic devices. In particular they are suited for cavity quantum electrodynamics in which strong coupling leads to polariton formation as a root to realisation of inversionless lasing, polariton condensationand superfluidity. Demonstrations of such strongly correlated phenomena to date have often relied on cryogenic temperatures, high excitation densities and were frequently impaired by strong material disorder. At room-temperature, experiments approaching the strong coupling regime with transition metal dichalcogenides have been reported, but well resolved exciton-polaritons have yet to be achieved. Here we report a study of monolayer WS$_2$ coupled to an open Fabry-Perot cavity at room-temperature, in which polariton eigenstates are unambiguously displayed. In-situ tunability of the cavity length results in a maximal Rabi splitting of $\hbar \Omega_{\rm{Rabi}} = 70$ meV, exceeding the exciton linewidth. Our data are well described by a transfer matrix model appropriate for the large linewidth regime. This work provides a platform towards observing strongly correlated polariton phenomena in compact photonic devices for ambient temperature applications.Comment: 12 pages, 6 figure

Nonsolar astronomy with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI)

The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) is a NASA Small Explorer satellite designed to study hard x-ray and gamma-ray emission from solar flares. In addition, its high-resolution array of germanium detectors can see photons from high-energy sources throughout the Universe. Here we discuss the various algorithms necessary to extract spectra, lightcurves, and other information about cosmic gamma-ray bursts, pulsars, and other astrophysical phenomena using an unpointed, spinning array of detectors. We show some preliminary results and discuss our plans for future analyses. All RHESSI data are public, and scientists interested in participating should contact the principal author

Unbiased Signal Equation for Quantitative Magnetization Transfer Mapping in Balanced Steady-State Free Precession MRI

Purpose: Quantitative magnetization transfer (qMT) imaging can be used to quantify the proportion of protons in a voxel attached to macromolecules. Here, we show that the original qMT balanced steady-state free precession (bSSFP) model is biased due to over-simplistic assumptions made in its derivation. Theory and Methods: We present an improved model for qMT bSSFP, which incorporates finite radio-frequency (RF) pulse effects as well as simultaneous exchange and relaxation. Further, a correction to finite RF pulse effects for sinc-shaped excitations is derived. The new model is compared to the original one in numerical simulations of the Bloch-McConnell equations and in previously acquired in-vivo data. Results: Our numerical simulations show that the original signal equation is significantly biased in typical brain tissue structures (by 7-20 %) whereas the new signal equation outperforms the original one with minimal bias (< 1%). It is further shown that the bias of the original model strongly affects the acquired qMT parameters in human brain structures, with differences in the clinically relevant parameter of pool-size-ratio of up to 31 %. Particularly high biases of the original signal equation are expected in an MS lesion within diseased brain tissue (due to a low T2/T1-ratio), demanding a more accurate model for clinical applications. Conclusion: The improved model for qMT bSSFP is recommended for accurate qMT parameter mapping in healthy and diseased brain tissue structures

Transport and Reaction Processes in Soil

In order to register agrochemicals in Europe it is necessary to have a detailed understanding of the processes in the environment that break down agrochemicals. The existing framework for environmental assessment includes a consideration of soil water movement and microbial breakdown of products in soil and these processes are relatively understood and represented in models. However the breakdown of agrochemicals by the action of light incident on the soil surface by a process termed photolysis is not so well represented in models of environmental fate. The problem brought by Syngenta (one of the worlds leading agrochemical companies) to the workshop was how to include the effects of light degradation of chemicals into predictive models of environmental fate. Photolysis is known to occur in a very thin layer at the surface of soil. The workshop was asked to consider how the very rough nature of the upper surface of a ploughed field might affect the degradation of chemicals by sunlight. The discussions were directed down two avenues: - firstly to determine how the very small distances over which photolysis occurs might be adequately incorporated into models of transport in soils and, - secondly to consider how the rough surface might modify the illumination of the surface and hence alter degradation. The rate of degradation by photolysis is measured in the laboratory by illuminating a thin, typically about 1 or 2 mm, layer of soil with very strong xenon lamps. The amount of chemical is measured at various intervals and is fitted to a first-order process. Field experiments where the chemical is sprayed on a bare field show evidence of photolysis indicated by biphasic degradation patterns and the presence of breakdown products only formed by photolysis. This report addresses methods for mathematically modelling the action of photolysis on particular relevant chemical species. We start with a general discussion of mechanisms that transport chemicals within soil §2. There is an existing computational model exploited by Syngenta for such modelling and we discuss how this performs and the predictions that can be derived using it §3. The particular mechanism of photolysis is then considered. One aspect of this mechanism that is investigated is how the roughness of the surface of the soil could be adequately incorporated into the modelling. Some results relating to this are presented §4.2. Some of the original experimental data used to derive aspects of the model of photolysis are revisited and a simple model of the process presented and shown to fit the data very well §5. By considering photolysis with a constant diffusion coefficient various analytical results are derived and general behaviour of the system outlined. This simple model is then applied to real field-based data and shown to give very good fit when simply extended to account for the moisture variations by utilising moisture dependent diffusion coefficients derived from the existing computational model §5.3. Some consequences of the simple model are then discussed §6

Influence of the structural modulations and the Chain-ladder interaction in the Sr_14−xCa_xCu_24O_41Sr\_{14-x}Ca\_{x}Cu\_{24}O\_{41} compounds

We studied the effects of the incommensurate structural modulations on the ladder subsystem of the $Sr\_{14-x}Ca\_{x}Cu\_{24}O\_{41}$ family of compounds using ab-initio explicitly-correlated calculations. From these calculations we derived $t-J$ model as a function of the fourth crystallographic coordinate $\tau$ describing the incommensurate modulations. It was found that in the highly calcium-doped system, the on-site orbital energies are strongly modulated along the ladder legs. On the contrary the two sites of the ladder rungs are iso-energetic and the holes are thus expected to be delocalized on the rungs. Chain-ladder interactions were also evaluated and found to be very negligible. The ladder superconductivity model for these systems is discussed in the light of the present results.Comment: 8 octobre 200