Interfacial Structure Dependent Spin Mixing Conductance in Cobalt Thin Films

Enhancement of Gilbert damping in polycrystalline cobalt thin-film multilayers of various thicknesses, overlayered with copper or iridium, was studied in order to understand the role of local interface structure in spin pumping. X-ray diffraction indicates that cobalt films less than 6 nm thick have strong fcc(111) texture while thicker films are dominated by hcp(0001) structure. The intrinsic damping for cobalt thicknesses above 6 nm is weakly dependent on cobalt thickness for both overlayer materials, and below 6 nm the iridium overlayers show higher damping enhancement compared to copper overlayers, as expected due to spin pumping. The interfacial spin mixing conductance is significantly enhanced in structures where both cobalt and iridium have fcc(111) structure in comparison to those where the cobalt layer has subtly different hcp(0001) texture at the interface

A New Model of Electron Pitch Angle Distributions and Loss Timescales in the Earth's Radiation Belts

As the number of satellites on orbit grows it is increasingly important to understand their operating environment. Physics-based models can simulate the behavior of the Earth's radiation belts by solving a Fokker-Planck equation. Three-dimensional models use diffusion coefficients to represent the interactions between electromagnetic waves and the electrons. One-dimensional radial diffusion models neglect the effects of energy diffusion and represent the losses due to the waves with a loss timescale. Both approaches may use pitch angle distributions (PADs) to create boundary conditions, to map observations from low to high equatorial pitch angles and to calculate phase-space density from observations. We present a comprehensive set of consistent PADs and loss timescales for 2 ≤ L* ≤ 7, 100 keV ≤ E ≤ 5 MeV and all levels of geomagnetic activity determined by the Kp index. These are calculated from drift-averaged diffusion coefficients that represent all the VLF waves that typically interact with radiation belt electrons and show good agreement with data. The contribution of individual waves is demonstrated; magnetosonic waves have little effect on loss timescales when lightning-generated whistlers are present, and chorus waves contribute to loss even in low levels of geomagnetic activity. The PADs vary in shape depending on the dominant waves. When chorus is dominant the distributions have little activity dependence, unlike the corresponding loss timescales. Distributions peaked near 90° are formed by plasmaspheric hiss for L* ≤ 3 and E 3 and E > 1 MeV. When hiss dominates, increasing activity broadens the distribution but when EMIC waves dominate increasing activity narrows the distribution

Balancing livestock production and wildlife conservation in and around southern Africa's transfrontier conservation areas

Biodiversity conservation, of which the transfrontier conservation area movement is an integral part, and more effective livestock production/trade are pivotal to future rural development in southern Africa. For that reason, it is imperative to effectively ameliorate the obstacles that have impeded progress towards the coexistence of these two sectors for more than half a century. Transboundary animal diseases, foot and mouth disease in particular, have been and continue to be the most important of these obstacles. Fortunately, new developments in international sanitary standards applicable to trade in commodities and products derived from animals are beginning to make a solution possible. However, while progress in principle has been achieved, practical implementation remains problematic for technical reasons, exacerbated by inconsistent attitudes towards acceptance of non-traditional international trade standards. This paper describes the background to this situation, progress that has been achieved in the recent past and remaining difficulties that need to be overcome to advance towards achievement of balanced rural development in southern Africa.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1865-1682hb2013ab201

Universal interpretations of vocal music

Despite the variability of music across cultures, some types of human songs share acoustic characteristics. For example, dance songs tend to be loud and rhythmic, and lullabies tend to be quiet and melodious. Human perceptual sensitivity to the behavioral contexts of songs, based on these musical features, suggests that basic properties of music are mutually intelligible, independent of linguistic or cultural content. Whether these effects reflect universal interpretations of vocal music, however, is unclear because prior studies focus almost exclusively on English-speaking participants, a group that is not representative of humans. Here, we report shared intuitions concerning the behavioral contexts of unfamiliar songs produced in unfamiliar languages, in participants living in Internet-connected industrialized societies (n = 5,516 native speakers of 28 languages) or smaller-scale societies with limited access to global media (n = 116 native speakers of three non-English languages). Participants listened to songs randomly selected from a representative sample of human vocal music, originally used in four behavioral contexts, and rated the degree to which they believed the song was used for each context. Listeners in both industrialized and smaller-scale societies inferred the contexts of dance songs, lullabies, and healing songs, but not love songs. Within and across cohorts, inferences were mutually consistent. Further, increased linguistic or geographical proximity between listeners and singers only minimally increased the accuracy of the inferences. These results demonstrate that the behavioral contexts of three common forms of music are mutually intelligible cross-culturally and imply that musical diversity, shaped by cultural evolution, is nonetheless grounded in some universal perceptual phenomena

A plasticity model for powder compaction processes incorporating particle deformation and rearrangement

This article is available open access through the publisher’s website at the link below. Copyright @ 2008 Elsevier Ltd.This paper develops a mechanistic model of granular materials that can be used with a commercial finite element package (ABAQUS). The model draws on the ideas of critical state soil mechanics and combines them with the theory of envelopes to develop an elasto-plastic model with a non-associated flow rule. The model incorporates both local deformation at the granule contacts, and rearrangement of the granules so that jointly they account for any bulk deformation. The mechanics of the model closely reflect the physicality of the material behaviour and the model parameters are closely linked (although not simplistically identical) to the characteristics of the granules. This not only gives an insight into the material behaviour, but also enables the model to be used to facilitate design of the material, its processing properties and, hence, component development. The model is used to simulate drained triaxial tests, settlement of a powder in a bin, and some examples of die pressing. Simulations are compared with experimental data and with predictions obtained using other models

International trade standards for commodities and products derived from animals : the need for a system that integrates food safety and animal disease risk management

A case is made for greater emphasis to be placed on value chain management as an alternative to geographically based disease risk mitigation for trade in commodities and products derived from animals. The geographic approach is dependent upon achievement of freedom in countries or zones from infectious agents that cause so-called transboundary animal diseases, while value chain-based risk management depends upon mitigation of animal disease hazards potentially associated with specific commodities or products irrespective of the locality of production. This commodity-specific approach is founded on the same principles upon which international food safety standards are based, viz. hazard analysis critical control points (HACCP). Broader acceptance of a value chain approach enables animal disease risk management to be combined with food safety management by the integration of commodity-based trade and HACCP methodologies and thereby facilitates ‘farm to fork’ quality assurance. The latter is increasingly recognized as indispensable to food safety assurance and is therefore a pre-condition to safe trade. The biological principles upon which HACCP and commodity-based trade are based are essentially identical, potentially simplifying sanitary control in contrast to current separate international sanitary standards for food safety and animal disease risks that are difficult to reconcile. A value chain approach would not only enable more effective integration of food safety and animal disease risk management of foodstuffs derived from animals but would also ameliorate adverse environmental and associated socio-economic consequences of current sanitary standards based on the geographic distribution of animal infections. This is especially the case where vast veterinary cordon fencing systems are relied upon to separate livestock and wildlife as is the case in much of southern Africa. A value chain approach would thus be particularly beneficial to under-developed regions of the world such as southern Africa specifically and sub-Saharan Africa more generally where it would reduce incompatibility between attempts to expand and commercialize livestock production and the need to conserve the subcontinent’s unparalleled wildlife and wilderness resources.US Agency for International Development (USAID) and The Rockefeller Foundationhttp://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1865-1682hb2013ab201

Crossovers and Phase Coherence in Cuprate Superconductors

High temperature superconductivity is a property of doped antiferromagnetic insulators. The electronic structure is inhomogeneous on short length and time scales, and, as the temperature decreases, it evolves via two crossovers, before long range superconducting order is achieved. Except for overdoped materials, pairing and phase coherence occur at different temperatures, and phase fluctuations determine both T$_c$ and the temperature dependence of the superfluid density for a wide range of doping. A mechanism for obtaining a high pairing scale in a short coherence length material with a strong poorly-screened Coulomb interaction is described.Comment: 5 pages, Latex, Revte

Morphology and Orientation Selection of Non-Metallic Inclusions in Electrified Molten Metal

The effect of electric current on morphology and orientation selection of non-metallic inclusions in molten metal has been investigated using theoretical modelling and numerical calculation. Two geometric factors, namely the circularity (fc) and alignment ratio (fe) were introduced to describe the inclusions shape and configuration. Electric current free energy was calculated and the values were used to determine the thermodynamic preference between different microstructures. Electric current promotes the development of inclusion along the current direction by either expatiating directional growth or enhancing directional agglomeration. Reconfiguration of the inclusions to reduce the system electric resistance drives the phenomena. The morphology and orientation selection follows the routine to reduce electric free energy. The numerical results are in agreement with our experimental observations

What Do “None,” “Mild,” “Moderate,” “Severe,” and “Very Severe” Mean to Patients With Cancer? Content Validity of PRO-CTCAE™ Response Scales

Accurate capture of the symptom experience is essential to gauging efficacy, safety, and tolerability of cancer treatments. The Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) was developed by the National Cancer Institute to allow direct patient self-reporting of symptomatic adverse events in cancer clinical trials. Its content validity has been established in accordance with recommended practices for novel patient-reported outcome (PRO) instruments

Pinning of stripes by local structural distortions in cuprate high-Tc superconductors

We study the spin-density wave (stripe) instability in lattices with mixed low-temperature orthorhombic (LTO) and low-temperature tetragonal (LTT) crystal symmetry. Within an explicit mean-field model it is shown how local LTT regions act as pinning centers for static stripe formation. We calculate the modulations in the local density of states near these local stripe regions and find that mainly the coherence peaks and the van Hove singularity (VHS) are spatially modulated. Lastly, we use the real-space approach to simulate recent tunneling data in the overdoped regime where the VHS has been detected by utilizing local normal state regions.Comment: Conference proceedings for Stripes1