Concept study for a high-efficiency nanowire-based thermoelectric

Materials capable of highly efficient, direct thermal-to-electric energy conversion would have substantial economic potential. Theory predicts that thermoelectric efficiencies approaching the Carnot limit can be achieved at low temperatures in one-dimensional conductors that contain an energy filter such as a double-barrier resonant tunneling structure. The recent advances in growth techniques suggest that such devices can now be realized in heterostructured, semiconductor nanowires. Here we propose specific structural parameters for InAs/InP nanowires that may allow the experimental observation of near-Carnot efficient thermoelectric energy conversion in a single nanowire at low temperature

Simulation of guiding of multiply charged projectiles through insulating capillaries

Recent experiments have demonstrated that highly charged ions can be guided through insulating nanocapillaries along the direction of the capillary axis for a surprisingly wide range of injection angles. Even more surprisingly, the transmitted particles remain predominantly in their initial charge state, thus opening the pathway to the construction of novel ion-optical elements without electric feedthroughs. We present a theoretical treatment of this self-organized guiding process. We develop a classical trajectory transport theory that relates the microscopic charge-up with macroscopic material properties. Transmission coefficients, angular spread of transmitted particles, and discharge characteristics of the target are investigated. Partial agreement with experiment is found

Corporate reporting and accounting for externalities

Externalities comprise economic, social and/or environmental impacts arising from the activities of an entity that are borne by others, at least in the short term. As they do not feedback directly into immediate financial consequences for the entity, they tend to be outside the remit of financial reporting. A dispersed academic accounting literature on externalities has hitherto developed separately from concerns about what information is appropriate to report on corporate performance. This paper develops insights into accounting for, and reporting of, externalities that are intended to improve the use of externalities information in breaking down silos between the traditionally discrete domains of financial reporting and sustainability reporting, and between silos within sustainability reporting. Challenges in such use of externalities information are explored, including difficulties inherent in the quantification of externalities. The paper also highlights ways in which externalities can progressively become internalised, thereby bringing them more readily within the domain of economically focused financial reporting practices. An agenda for further research to help enhance the accounting for, and reporting of, externalities is also proposed. © 2018 Informa UK Limited, trading as Taylor & Francis Group

Analysis of surface waves generated on subwavelength-structured silver films

Using transmission electron microscopy (TEM) to analyse the physical-chemical surface properties of subwavlength structured silver films and finite-difference time-domain (FDTD) numerical simulations of the optical response of these structures to plane-wave excitation, we report on the origin and nature of the persistent surface waves generated by a single slit-groove motif and recently measured by far-field optical interferometry. The surface analysis shows that the silver films are free of detectable oxide or sulfide contaminants, and the numerical simulations show very good agreement with the results previously reported.Comment: 9 Figure

On the usefulness of two small-scale in vitro setups in the evaluation of luminal precipitation of lipophilic weak bases in early formulation development

A small-scale biphasic dissolution setup and a small-scale dissolution-permeation (D-P) setup were evaluated for their usefulness in simulating the luminal precipitation of three lipophilic weak bases—dipyridamole, ketoconazole and itraconazole. The transition from the gastric to intestinal environment was incorporated into both experimental procedures. Emulsification during the biphasic dissolution experiments had a minimal impact on the data, when appropriate risk mitigation steps were incorporated. Precipitation parameters estimated from the in vitro data were inputted into the Simcyp® physiologically based pharmacokinetic (PBPK) modelling software and simulated human plasma profiles were compared with previously published pharmacokinetic data. Average Cmax and AUC values estimated using experimentally derived precipitation parameters from the biphasic experiments deviated from corresponding published actual values less than values estimated using the default simulator parameters for precipitation. The slow rate of transport through the biomimetic membrane in the D-P setup limited its usefulness in forecasting the rates of in vivo precipitation used in the modelling of average plasma profiles

Is Foundational Movement Skill Competency Important for Keeping Children Physically Active and at a Healthy Weight?

This longitudinal study examines the associations between foundational movement skills (FMS) competency, moderate-to-vigorous physical activity (MVPA) and weight status among children (n = 75) attending preschools in deprived areas from early to late childhood. Twelve FMS were assessed using the Children’s Activity and Movement in Preschool Motor Skills Protocol and video analysis. Physical activity was measured via hip-mounted accelerometry. Data was collected over a five-year period, with Baseline Follow Up data collected between 2010 and 2015. There was an overall pattern of increase for total, object-control and locomotor scores between Baseline and Follow-Up. Conversely, there was an overall pattern of decline for MVPA among participants. There was a positive significant (p < 0.05) association between total and locomotor scores and MVPA at Baseline. However, these associations weakened over time and no significant associations were found at Follow-Up. Baseline competency failed to predict Follow-Up MVPA or weight status. Likewise, Baseline MVPA was not found to be a predictor of Follow-Up FMS competency. Further longitudinal research is required to explore these associations among children from highly deprived areas. Future interventions may require a more holistic approach to improving FMS competency and increasing PA in order to account for the number of variables that can affect these outcomes

Epidemic spread of smut fungi (Quambalaria) by sexual reproduction in a native pathosystem

Quambalaria are fungal pathogens of Corymbia, Eucalyptus and related genera of Myrtaceae. They are smut fungi (Ustilaginomycota) described from structures that resemble conidia and conidiophores. Whether these spore forms have asexual or sexual roles in life cycles of Quambalaria is unknown. An epidemic of Q. pitereka destroyed plantations of Corymbia in New South Wales and Queensland (Australia) in 2008. We sampled 177 individuals from three plantations of C. variegata and used AFLPs to test hypotheses that the epidemic was spread by asexual reproduction and dominated by a single genotype. There was high genotypic diversity across ≥600 AFLP loci in the pathogen populations at each plantation, and evidence of sexual reproduction based on neighbour-net analyses and rejection of linkage disequilibrium. The populations were not structured by host or location. Our data did not support a hypothesis of asexual reproduction but instead that Q. pitereka spreads exclusively by sexual reproduction, similar to life cycles of other smut fungi. Epidemics were exacerbated by monocultures of Corymbia established from seed collected from a single provenance. This study showcases an example of an endemic pathogen, Q. pitereka, with a strictly outbreeding life cycle that has caused epidemics when susceptible hosts were planted in large monoculture plantations

Seeking “conversations for accountability”:Mediating the impact of non-governmental organization (NGO) upward accountability processes

Purpose: The purpose of this paper is to ascertain how upward accountability processes can be enabling in, or constraining to, the effective deployment of development aid funding. Design/methodology/approach: The paper derives its primary insights from in-depth interviews and focus groups with non-governmental organization (NGO) fieldworkers working and delivering development aid in Northern Ghana. It analyses inductively the perspectives of fieldworkers to explain their experiences of upward accountability. Findings: The fieldworkers’ perception of upward accountability was mainly one of external control, in response to which they enacted a skilful form of compliance accountability. This perception of control failed to stifle their initiative and intrinsic commitment to beneficiaries. The fieldworkers craved “conversations for accountability”, in which they had a voice in the development of upward accountability metrics, thereby enabling them to fulfil their sense of felt responsibility to beneficiaries. While aspects of “conversations for accountability” were emerging in fieldworker-funder interactions, it was unclear to what extent funders were committed to further advancing them. Overall, the analysis unveils how felt responsibility mediates for, and partly diminishes, the perceived negative impacts on aid effectiveness of upward accountability processes informed by a focus on control. Originality/value: The authors examine the potential of upward accountability processes using in-depth analyses of the actual experiences of those involved in delivering NGO services at the grassroots level. The authors contribute to emerging work in this vein by enriching the authors’ understanding of local constituencies’ experiences of accountability processes more generally, especially the impact these mechanisms have on NGO operational activities. The authors also unveil the mediating role fieldworkers’ “felt responsibility” to beneficiaries’ plays in moderating the perceived negative impacts on aid effectiveness of upward accountability processes. © 2017, © Emerald Publishing Limited

Electron beam charging of insulators: A self-consistent flight-drift model

International audienceElectron beam irradiation and the self-consistent charge transport in bulk insulating samples are described by means of a new flight-drift model and an iterative computer simulation. Ballistic secondary electron and hole transport is followed by electron and hole drifts, their possible recombination and/or trapping in shallow and deep traps. The trap capture cross sections are the Poole-Frenkel-type temperature and field dependent. As a main result the spatial distributions of currents j(x,t), charges, the field F(x,t) and the potential slope V(x,t) are obtained in a self-consistent procedure as well as the time-dependent secondary electron emission rate sigma(t) and the surface potential V0(t) For bulk insulating samples the time-dependent distributions approach the final stationary state with j(x,t)=const=0 and sigma=1. Especially for low electron beam energies E0=4 keV the incorporation of mainly positive charges can be controlled by the potential VG of a vacuum grid in front of the target surface. For high beam energies E0=10, 20, and 30 keV high negative surface potentials V0=−4, −14, and −24 kV are obtained, respectively. Besides open nonconductive samples also positive ion-covered samples and targets with a conducting and grounded layer (metal or carbon) on the surface have been considered as used in environmental scanning electron microscopy and common SEM in order to prevent charging. Indeed, the potential distributions V(x) are considerably small in magnitude and do not affect the incident electron beam neither by retarding field effects in front of the surface nor within the bulk insulating sample. Thus the spatial scattering and excitation distributions are almost not affected