6,504 research outputs found

    Making the most of community energies:Three perspectives on grassroots innovation

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    Grassroots innovations for sustainability are attracting increasing policy attention. Drawing upon a wide range of empirical research into community energy in the UK, and taking recent support from national government as a case study, we apply three distinct analytical perspectives: strategic niche management; niche policy advocacy; and critical niches. Whilst the first and second perspectives appear to explain policy influence in grassroots innovation adequately, each also shuts out more transformational possibilities. We therefore argue that, if grassroots innovation is to realise its full potential, then we need to also pursue a third, critical niches perspective, and open up debate about more socially transformative pathways to sustainability

    Wireless transfer of power by a 35-GHz metamaterial split-ring resonator rectenna

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    Wireless transfer of power via high frequency microwave radiation using a miniature split ring resonator rectenna is reported. RF power is converted into DC power by integrating a rectification circuit with the split ring resonator. The near-field behavior of the rectenna is investigated with microwave radiation in the frequency range between 20-40 GHz with a maximum power level of 17 dBm. The observed resonance peaks match those predicted by simulation. Polarization studies show the expected maximum in signal when the electric field is polarized along the edge of the split ring resonator with the gap and minimum for perpendicular orientation. The efficiency of the rectenna is on the order of 1% for a frequency of 37.2 GHz. By using a cascading array of 9 split ring resonators the output power was increased by a factor of 20

    The impact of clinical clerkships on medical students’ attitudes toward contraception and abortion: a pilot study

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    Objective: Investigate the impact of clinical clerkships on medical students’ attitudes toward contraception and abortion. Methods: As part of their required curriculum, second-year medical students at the University of Iowa complete an anonymous survey that presents eight questions involving specific contraception and abortion scenarios. In this pilot study, all 159 members of the Class of 2013 who had previously completed this required anonymous survey were invited to re-take the survey at the conclusion of their fourth year. Additional questions, asking the students if they felt that clinical clerkships had changed their perspectives on contraception and abortion in general, were included. Results: Of the 159 members of the Class of 2013, 42 volunteered to participate, for a response rate of 26%. Twenty students (47.62%) felt that clinical clerkships had changed their perspectives on contraception and thirteen students (39.95%) felt that clinical clerkships had changed their perspectives on abortion. The percentage of students who felt comfortable referring a patient to a colleague for an abortion increased significantly from 71.33% to 90.48% (p=0.024). Responses to the other seven questions included in the survey did not differ significantly pre and post-clerkships. Conclusions: This pilot study, although limited by a low response rate, suggests that clinical clerkships have the ability to impact medical students’ attitudes toward contraception and abortion in general, as well as toward specific scenarios involving abortion

    Can processes make relationships work? The Triple Helix between structure and action

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    This contribution seeks to explore how complex adaptive theory can be applied at the conceptual level to unpack Triple Helix models. We use two cases to examine this issue – the Finnish Strategic Centres for Science, Technology & Innovation (SHOKs) and the Canadian Business-led Networks of Centres of Excellence (BL-NCE). Both types of centres are organisational structures that aspire to be business-led, with a considerable portion of their activities driven by (industrial) users’ interests and requirements. Reflecting on the centres’ activities along three dimensions – knowledge generation, consensus building and innovation – we contend that conceptualising the Triple Helix from a process perspective will improve the dialogue between stakeholders and shareholders

    Edge-Based Compartmental Modeling for Infectious Disease Spread Part III: Disease and Population Structure

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    We consider the edge-based compartmental models for infectious disease spread introduced in Part I. These models allow us to consider standard SIR diseases spreading in random populations. In this paper we show how to handle deviations of the disease or population from the simplistic assumptions of Part I. We allow the population to have structure due to effects such as demographic detail or multiple types of risk behavior the disease to have more complicated natural history. We introduce these modifications in the static network context, though it is straightforward to incorporate them into dynamic networks. We also consider serosorting, which requires using the dynamic network models. The basic methods we use to derive these generalizations are widely applicable, and so it is straightforward to introduce many other generalizations not considered here

    Measures Matter: Scales for Adaptation, Cultural Distance, and Acculturation Orientation Revisited

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    Building upon existing measures, four new brief acculturation scales are presented, measuring sociocultural adaptation, psychological adaptation, perceived cultural distance, and acculturation orientation. Following good scale reliability in initial samples, the English scales were translated into nine different languages (Chinese, French, German, Italian, Japanese, Portuguese, Spanish, Thai, and Turkish). The translated scales were administered to a large sample of sojourners (N = 1,929), demonstrating good reliability and adequate structural equivalence across languages. In line with existing theory, sociocultural adaptation and psychological adaptation were positively correlated, and showed a negative association with perceived cultural distance. General measures of well-being were correlated with adaptation and distance, with better adaptation relating to higher well-being, and more distance relating to lower well-being. Acculturation orientation toward the home and host culture were measured separately and a weak negative correlation was found between the two, supporting their independence. Arguing against dichotomization, these subscales were analyzed as continuous variables. Regression analysis showed sojourners to be better adapted, if they were oriented more toward the host culture and less toward the home culture. These new scales are proposed as alternatives to existing measures

    Probing the potential of mucus permeability to signify preterm birth risk

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    Preterm birth is the leading cause of neonatal mortality, and is frequently associated with intra-amniotic infection hypothesized to arise from bacterial ascension across a dysfunctional cervical mucus plug. To study this dysfunction, we assessed the permeability of cervical mucus from non-pregnant ovulating (n = 20) and high-(n = 9) and low-risk (n = 16) pregnant women to probes of varying sizes and surface chemistries. We found that the motion of negatively charged, carboxylated microspheres in mucus from pregnant patients was significantly restricted compared to ovulating patients, but not significantly different between high-A nd low-risk pregnant women. In contrast, charged peptide probes small enough to avoid steric interactions, but sensitive to the biochemical modifications of mucus components exhibited significantly different transport profiles through mucus from high-A nd low-risk patients. Thus, although both microstructural rearrangements of the components of mucus as well as biochemical modifications to their adhesiveness may alter the overall permeability of the cervical mucus plug, our findings suggest that the latter mechanism plays a dominant role in the impairment of the function of this barrier during preterm birth. We expect that these probes may be readily adapted to study the mechanisms underlying disease progression on all mucosal epithelia, including those in the mouth, lungs, and gut.National Science Foundation (U.S.) (Award DMR-0819762)National Science Foundation (U.S.) (Award 1122374

    Rotation Measure Synthesis of Galactic Polarized Emission with the DRAO 26-m Telescope

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    Radio polarimetry at decimetre wavelengths is the principal source of information on the Galactic magnetic field. The diffuse polarized emission is strongly influenced by Faraday rotation in the magneto-ionic medium and rotation measure is the prime quantity of interest, implying that all Stokes parameters must be measured over wide frequency bands with many frequency channels. The DRAO 26-m Telescope has been equipped with a wideband feed, a polarization transducer to deliver both hands of circular polarization, and a receiver, all operating from 1277 to 1762 MHz. Half-power beamwidth is between 40 and 30 arcminutes. A digital FPGA spectrometer, based on commercially available components, produces all Stokes parameters in 2048 frequency channels over a 485-MHz bandwidth. Signals are digitized to 8 bits and a Fast Fourier Transform is applied to each data stream. Stokes parameters are then generated in each frequency channel. This instrument is in use at DRAO for a Northern sky polarization survey. Observations consist of scans up and down the Meridian at a drive rate of 0.9 degree per minute to give complete coverage of the sky between declinations -30 degree and 90 degree. This paper presents a complete description of the receiver and data acquisition system. Only a small fraction of the frequency band of operation is allocated for radio astronomy, and about 20 percent of the data are lost to interference. The first 8 percent of data from the survey are used for a proof-of-concept study, which has led to the first application of Rotation Measure Synthesis to the diffuse Galactic emission obtained with a single-antenna telescope. We find rotation measure values for the diffuse emission as high as approximately 100 rad per square metre, much higher than recorded in earlier work.Comment: Accepted for publication in The Astronomical Journa

    M-theory Compactifications on Manifolds with G2 Structure

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    In this paper we study M-theory compactifications on manifolds of G2 structure. By computing the gravitino mass term in four dimensions we derive the general form for the superpotential which appears in such compactifications and show that beside the normal flux term there is a term which appears only for non-minimal G2 structure. We further apply these results to compactifications on manifolds with weak G2 holonomy and make a couple of statements regarding the deformation space of such manifolds. Finally we show that the superpotential derived from fermionic terms leads to the potential that can be derived from the explicit compactification, thus strengthening the conjectures we make about the space of deformations of manifolds with weak G2 holonomy.Comment: 34 pages. Minor changes: typos corrected, references added. Version to appear in Class. Quantum Gra

    The glossy trait in sorghum: Its characteristics and significance in crop improvement

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    Sorghum seedlings can be morphologically glossy or nonglossy: seedlings with dark green leaves (normal) are nonglossy, and seedlings with light yellow green and shining leaf surface are glossy. A systematic study of the world sorghum germplasm collection indicated a low frequency of accessions with the glossy trait (only 495 of 17 536 germplasm accessions screened). A large proportion (84%) of the glossy lines were of Indian origin but some were from elsewhere (Nigeria, Sudan, Cameroun, Ethiopia, Kenya, Uganda, South Africa, and Mexico). Most of the glossy lines are in the durra group but some are from the taxonomic groups guinea, caudatum, and bicolor. Glossy lines vary in morphological, anatomical, and agronomic attributes, many being extremely late or photoperiod-sensitive and very tall. Some lines are early maturing, intermediate to dwarf in height and agronomically good. Studies have indicated that glossy lines contribute to shootfly resistance and seedling drought resistance. Source material for the glossy trait is maintained by the Genetic Resources Unit at ICRISAT
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