Vortex/boundary-layer interactions: Data report, volume 1

This report summarizes the work done under NASA Grant NAGw-581, Vortex/Boundary Layer Interactions. The experimental methods are discussed in detail and numerical results are presented, but are not fully interpreted. This report should be useful to anyone who wishes to make further use of the data (available on floppy disc or magnetic tape) for the development of turbulence models or the validation of predictive methods. Journal papers are in course of preparation

Capillary acquisition devices for high-performance vehicles: Executive summary

Technology areas critical to the development of cryogenic capillary devices were studied. Passive cooling of capillary devices was investigated with an analytical and experimental study of wicking flow. Capillary device refilling with settled fluid was studied using an analytical and experimental program that resulted in successful correlation of a versatile computer program with test data. The program was used to predict Centaur D-1S LO2 and LH2 start basket refilling. Comparisons were made between the baseline Centaur D-1S propellant feed system and feed system alternatives including systems using capillary devices. The preferred concepts from the Centaur D-1S study were examined for APOTV and POTV vehicles for delivery and round trip transfer of payloads between LEO and GEO. Mission profiles were determined to provide propellant usage timelines and the payload partials were defined

Child Well-being in the Pacific Rim

This study extends previous efforts to compare the well-being of children using multi-dimensional indicators derived from sample survey and administrative series to thirteen countries in the Pacific Rim. The framework for the analysis of child well-being is to organise 46 indicators into 21 components and organise the components into 6 domains: material situation, health, education, subjective well-being, living environment, as well as risk and safety. Overall, Japan, Singapore and Taiwan have the highest child well-being and Thailand, Indonesia and the Philippines the lowest. However, there are substantial variations between the domains. Japan and Korea perform best on the material well-being of children and also do well on health and education but they have the lowest subjective well-being among their children by some margin. There is a relationship between child well-being and GDP per capita but children in China have higher well-being than you would expect given their GDP and children in Australia have lower well-being. The analysis is constrained by missing data particularly that the Health Behaviour of School-Aged Children Survey is not undertaken in any of these countries

Laser-controlled fluorescence in two-level systems

The ability to modify the character of fluorescent emission by a laser-controlled, optically nonlinear process has recently been shown theoretically feasible, and several possible applications have already been identified. In operation, a pulse of off-resonant probe laser beam, of sufficient intensity, is applied to a system exhibiting fluorescence, during the interval of excited- state decay following the initial excitation. The result is a rate of decay that can be controllably modified, the associated changes in fluorescence behavior affording new, chemically specific information. In this paper, a two-level emission model is employed in the further analysis of this all-optical process; the results should prove especially relevant to the analysis and imaging of physical systems employing fluorescent markers, these ranging from quantum dots to green fluorescence protein. Expressions are presented for the laser-controlled fluorescence anisotropy exhibited by samples in which the fluorophores are randomly oriented. It is also shown that, in systems with suitably configured electronic levels and symmetry properties, fluorescence emission can be produced from energy levels that would normally decay nonradiatively. © 2010 American Chemical Society

UK and EU policy for approval of pesticides suitable for organic systems: Implications for Wales

This study was commissioned by the Welsh Assembly Government (WAG) to review the pesticide approval system in the UK and Europe as far as it affects the use of substances and techniques for crop protection by organic producers in Wales. WAG considers it important that the UK pesticide approval system does not present unnecessary barriers to the development of organic production in Wales. Key Recommendations and scope for further work · WAG should work with the Pesticides Safety Directorate to ensure that the development of pesticide regulatory policy at both National and European level takes full account of the needs of both conventional and organic agriculture and horticulture in the UK. · There is scope for WAG to support the development of a National Pesticide Policy so that regulatory and commercial barriers impeding the development of organic pesticides are minimised. Not only could greater availability of ‘organic pesticides’ have a significant impact on organic production in Wales but there could be important implications for conventional horticulture systems and the use of alternatives to conventional pesticides. · One important regulatory barrier to the registration of ‘organic pesticides’ is the MRL requirement(s) for their approval and this needs to be resolved. Suitable analytical techniques are required to determine firstly whether these substances result in residues, and secondly to identify the breakdown and residue pathways. So far, this issue has not received the attention of any EU Member State. · According to the proposed framework for the 4th Stage Review of EU Pesticides Directive 91/414, notifiers are required to produce a dossier, at their own expense, covering characterisation, human toxicity, ecotoxicity efficacy and other relevant data. The Review includes specific provision for companies notifying the same substance to submit a shared dossier. This will help those businesses (many of which are relatively small companies) to save on the high cost of producing the dossiers. It will also aid the Commission since it will reduce the number of dossiers that have to be considered, and ensure that all the available data is included. WAG should encourage and support the production of collective dossiers; although as yet there is no indication of how this will be done in practice, and further details from the Commission are awaited. · This study has concluded that access to a wider range of ‘organically acceptable pesticides’ would not have a dramatic impact on organic production in Wales. However, in developing an integrated organic policy, WAG should continue to address the pesticides issue. Some of the methods of pest & disease control in organic systems are either physical or multi-cellular e.g. micro-organisms used as biocontrol agents. WAG agri environment policy may provide a vehicle to promote these techniques much more actively. Further, it is important to recognise that while Wales alone is too small to have a major impact on commercial and regulatory pressures, WAG can have an impact by working pro-actively with others to make progress. · There are no published EU or national Member State criteria that can be used to evaluate the acceptability of pesticide substances for organic production. Identifying such criteria and promoting their acceptance at EU level and nationally would allow more active substances to be made available. WAG should work with PSD and others to identify appropriate criteria. · The specific provisions of Article 7 in Annex 2(b) of the Organic Regulation (2092/91) place potential barriers to the adoption of organically acceptable substances for crop protection. There are a number of potentially useful substances currently not included in the Organic Regulation e.g. potassium bicarbonate. WAG should work with PSD and others to identify such substances and support the production of appropriate dossiers. WAG could also encourage further dialogue between the organic sector and Defra to identify amendments in the Organic Regulations to facilitate the inclusion of new pesticides. · Organic pest and disease management is not just a question of inputs but it also relies crucially on advice and extension through initiatives such as Farming Connect and the work of Organic Centre Wales. Long-term commitment to supporting on going advice and extension activities is vital to promote and disseminate best practice in Welsh agriculture and horticulture. · Organic horticulture, vegetable and fruit production systems are particularly sensitive to pest and disease management. Successful control of pests, diseases (and weeds) in these sectors can be critical to the business, and is not assured even when all husbandry and management methods have been effectively applied. Consequently, the use of organically acceptable crop protection methods resulting from future developments (e.g. biopesticides, biological control agents) could have an important role in pest and disease management in these sectors. Both organic and conventional producers in Wales could benefit from having these options available to them and WAG could encourage the adoption of these approaches through appropriate Technology Transfer activities. · The way in which such substances will be regulated at a European level in future is evolving as the review of the Pesticide Directive 91/414 EEC enters the 4th Stage. This stage of the review includes (amongst others) those substances permitted for use in organic production. The guidance documents for the evaluation of applications on plant protection products made from plants or plant extracts and from chemical substances are currently at the draft stage. The response of the Pesticide Safety Directorate and Defra to these developments is not yet clear but this provides an excellent opportunity for WAG to have an input at an early stage in the review process

Raman scattering mediated by neighboring molecules

Raman scattering is most commonly associated with a change in vibrational state within individual molecules, the corresponding frequency shift in the scattered light affording a key way of identifying material structures. In theories where both matter and light are treated quantum mechanically, the fundamental scattering process is represented as the concurrent annihilation of a photon from one radiation mode and creation of another in a different mode. Developing this quantum electrodynamical formulation, the focus of the present work is on the spectroscopic consequences of electrodynamic coupling between neighboring molecules or other kinds of optical center. To encompass these nanoscale interactions, through which the molecular states evolve under the dual influence of the input light and local fields, this work identifies and determines two major mechanisms for each of which different selection rules apply. The constituent optical centers are considered to be chemically different and held in a fixed orientation with respect to each other, either as two components of a larger molecule or a molecular assembly that can undergo free rotation in a fluid medium or as parts of a larger, solid material. The two centers are considered to be separated beyond wavefunction overlap but close enough together to fall within an optical near-field limit, which leads to high inverse power dependences on their local separation. In this investigation, individual centers undergo a Stokes transition, whilst each neighbor of a different species remains in its original electronic and vibrational state. Analogous principles are applicable for the anti-Stokes case. The analysis concludes by considering the experimental consequences of applying this spectroscopic interpretation to fluid media; explicitly, the selection rules and the impact of pressure on the radiant intensity of this process

Chiral discrimination in optical binding

The laser-induced intermolecular force that exists between two or more particles in the presence of an electromagnetic field is commonly termed “optical binding.” Distinct from the single-particle forces that are at play in optical trapping at the molecular level, the phenomenon of optical binding is a manifestation of the coupling between optically induced dipole moments in neutral particles. In other, more widely known areas of optics, there are many examples of chiral discrimination—signifying the different response a chiral material has to the handedness of an optical input. In the present analysis, extending previous work on chiral discrimination in optical binding, a mechanism is identified using a quantum electrodynamical approach. It is shown that the optical binding force between a pair of chiral molecules can be significantly discriminatory in nature, depending upon both the handedness of the interacting particles and the polarization of the incident light, and it is typically several orders of magnitude larger than previously reported

Fall armyworm (Spodoptera frugiperda Smith) feeding elicits differential defense responses in upland and lowland switchgrass

Switchgrass (Panicum virgatum L.) is a low input, high biomass perennial grass being developed for the bioenergy sector. Upland and lowland cultivars can differ in their responses to insect herbivory. Fall armyworm [FAW; Spodoptera frugiperda JE Smith (Lepidoptera: Noctuidae)] is a generalist pest of many plant species and can feed on switchgrass as well. Here, in two different trials, FAW larval mass were significantly reduced when fed on lowland cultivar Kanlow relative to larvae fed on upland cultivar Summer plants after 10 days. Hormone content of plants indicated elevated levels of the plant defense hormone jasmonic acid (JA) and its bioactive conjugate JA-Ile although significant differences were not observed. Conversely, the precursor to JA, 12-oxo-phytodienoic acid (OPDA) levels were significantly different between FAW fed Summer and Kanlow plants raising the possibility of differential signaling by OPDA in the two cultivars. Global transcriptome analysis revealed a stronger response in Kanlow plant relative to Summer plants. Among these changes were a preferential upregulation of several branches of terpenoid and phenylpropanoid biosynthesis in Kanlow plants suggesting that enhanced biosynthesis or accumulation of antifeedants could have negatively impacted FAW larval mass gain on Kanlow plants relative to Summer plants. A comparison of the switchgrass-FAW RNA-Seq dataset to those from maize-FAW and switchgrass-aphid interactions revealed that key components of plant responses to herbivory, including induction of JA biosynthesis, key transcription factors and JA-inducible genes were apparently conserved in switchgrass and maize. In addition, these data affirm earlier studies with FAW and aphids that the cultivar Kanlow can provide useful genetics for the breeding of switchgrass germplasm with improved insect resistance

A photoemission study of the surface carbonate species on Ag{110}

The electronic structure of the surface carbonate species adsorbed on Ag{110} has been studied with angle‐resolved photoemission using synchrotron radiation. Despite the low symmetry of the surface complex (Cs) and more than one azimuthal orientation of the vertical symmetry plane, it has been possible to assign the adsorbate‐induced levels. Recent semiempirical quantum chemical calculations have proved to be of considerable assistance in this process. The resonant behavior observed for the 3a‘ level is discussed in the context of photoelectron data for the free BF3 molecule, which is isoelectronic with CO2−3. The Cs symmetry pertaining in the present experiment is compared with the effective D3h symmetry observed in x‐ray‐absorption spectroscopy of the same system