Anisotropic magneto-Coulomb effect versus spin accumulation in a ferromagnetic single-electron device

We investigate the magneto-transport characteristics of nanospintronics single-electron devices. The devices consist of single non-magnetic nano-objects (nanometer size nanoparticles of Al or Cu) connected to Co ferromagnetic leads. The comparison with simulations allows us attribute the observed magnetoresistance to either spin accumulation or anisotropic magneto-Coulomb effect (AMC), two effects with very different origins. The fact that the two effects are observed in similar samples demonstrates that a careful analysis of Coulomb blockade and magnetoresistance behaviors is necessary in order to discriminate them in magnetic single-electron devices. As a tool for further studies, we propose a simple way to determine if spin transport or AMC effect dominates from the Coulomb blockade I-V curves of the spintronics device

Fauna and flora of the Great Barrier Reef World Heritage Area : a compendium of information and basis for the species conservation program in the Great Barrier Reef Marine Park Authority: second edition

The way in which the Great Barrier Reef Marine Park Authority (GBRMPA) manages for the conservation of species in the GBRMP is determined mainly by legislative instruments and policy decisions, which are supported by education and enforcement. Given the migratory nature of many species, the GBRMPA works closely with other Australian and Queensland Government agencies to ensure complementary management approaches as far as possible. This Report is a compendium of information on the fauna and flora of the GBRWHA and explains the rationale behind the work priorities of the Species Conservation Program of the GBRMPA, which focuses on the management of threatened species. The Report will be reviewed and updated as additional information becomes available and in the light of changes to conservation priorities

Electric-field control of domain wall nucleation and pinning in a metallic ferromagnet

The electric (E) field control of magnetic properties opens the prospects of an alternative to magnetic field or electric current activation to control magnetization. Multilayers with perpendicular magnetic anisotropy (PMA) have proven to be particularly sensitive to the influence of an E-field due to the interfacial origin of their anisotropy. In these systems, E-field effects have been recently applied to assist magnetization switching and control domain wall (DW) velocity. Here we report on two new applications of the E-field in a similar material : controlling DW nucleation and stopping DW propagation at the edge of the electrode

First steps in the development of a water temperature model framework for refining the ecological Reserve in South African rivers

Ecological Reserve determination for rivers in South Africa presently does not include a water temperature component, in spite of its importance in determining species distribution patterns. To achieve this requires an understanding of how lotic thermographs from South African rivers differ from northern hemisphere rivers, to avoid mismanaging rivers based on incorrect regional assumptions. Hourly water temperatures from 20 sites in four river systems, representing a range of latitudes, altitudes and stream orders, were assessed using a range of metrics. These data were analysed using principal component analyses and multiple linear regressions to understand what variables a water temperature model for use in ecoregions within South Africa should include. While temperature data are generally lacking in low- and higher-order South African rivers, data suggest that South African rivers are warmer than northern hemisphere rivers. Water temperatures could be grouped into cool, warm and intermediate types. Based on temperature time series analyses, this paper argues that a suitable water-temperature model for use in ecological Reserve determinations should be dynamic, include flow and air temperature variables, and be adaptive through a heat exchange coefficient term. The inclusion of water temperature in the determination and management of river ecological Reserves would allow for more holistic application of the National Water Act’s ecological management provisions. Water temperature guidelines added to the ecological Reserve could be integrated into heuristic aquatic monitoring programmes within priority areas identified in regional conservation plans.Keywords: water temperatures, conservation planning, water temperature modelling, managemen

Prediction of water temperature metrics using spatial modelling in the Eastern and Western Cape, South Africa

Key aspects of a river's temperature regime are described by magnitudes, timing and durations of thermal events, and frequencies of extreme exceedance events. To understand alterations to thermal regimes, it is necessary to describe thermal time series based on these statistics. Classification of sites based on their thermal metrics, and understanding of spatial patterns of these thermal statistics, provides a powerful approach for comparing study sites against reference sites. Water temperature regime dynamics should be viewed regionally, where regional divisions have an inherent underpinning by an understanding of natural thermal variability. The aim of this research was to link key water temperature metrics to readily-mapped environmental surrogates, and to produce spatial images of temperature metrics: 37 temperature metrics were derived for 12 months of sub-daily water temperatures at 90 sites in the Eastern Cape and Western Cape provinces, South Africa. These metrics were correlated with 16 environmental variables. Correlations enabled development of multiple regression models which facilitated mapping of temperature metrics over the study area. This approach has the potential to be applied at a national scale as more thermal time series are collected nationally. It is argued that the appropriateness of management decisions in rivers can be improved by including guidelines for thermal metrics at a regional scale. Such maps could facilitate incorporation of a temperature component into management guidelines for water resources

Spin injection in a single metallic nanoparticle: a step towards nanospintronics

We have fabricated nanometer sized magnetic tunnel junctions using a new nanoindentation technique in order to study the transport properties of a single metallic nanoparticle. Coulomb blockade effects show clear evidence for single electron tunneling through a single 2.5 nm Au cluster. The observed magnetoresistance is the signature of spin conservation during the transport process through a non magnetic cluster.Comment: 3 page

A study investigating the effects of modified goggle optical designs on swimmer performance

Background: Use of prisms to improve comfort and posture is a common practice in optometry. This concept can be expanded into the competitive sports world by incorporating prisms into swim goggles. Prisms can theoretically allow the competitive swimmer to maintain a more efficient posture throughout their event. The current study assesses the potential benefits of base-up prism in goggles for free-style swimming. Method: Twenty-four collegiate swimmers were surveyed and tested. Each participant filled out an initial survey detailing their preferences and concerns pertaining to competition goggles. All swimmers performed two 1500-meter practices with the prototype, 35 prism diopter (p.d.), goggles prior to testing. Testing consisted of swimming a 200-meter timed trial with each of the experimental goggles and filling out a corresponding survey immediately after each trial. 35 p.d. base-up prism prototype goggles, 1 p.d. base-up prism goggles, and plano control goggles were evaluated by each participant. Results: Fit was the most important concern for these swimmers. Fit also had the lowest standard deviation, denoting a common level of concern among most of the participants. The second most important concern for these swimmers was fogging. The least important concern for the participants was drag, which had the second lowest number of responders. Swimmers also thought that clarity of the goggles was important. Swimmers thought that restriction of peripheral vision was one of the least important problems. The 1 p.d. goggle produced the fastest mean time, and yet was ranked the worst by participants. In the surveys following the time trials, participants specified that their posture and field of view were greatly improved with the 35 p.d. goggles. They were also willing to pay more for the 35 p.d. goggles than the plano goggles. Conclusion: Although the swimmers swam faster with the 35 p.d. goggles and ranked them higher than the plano goggles, these differences were not statistically significant. However, significantly more subjects did perceive the 35 p.d. goggles to be more beneficial than plano or 1 p.d. goggles

Refactoring preserves security

Refactoring allows changing a program without changing its behaviour from an observer’s point of view. To what extent does this invariant of behaviour also preserve security? We show that a program remains secure under refactoring. As a foundation, we use the Decentralized Label Model (DLM) for specifying secure information flows of programs and transition system models for their observable behaviour. On this basis, we provide a bisimulation based formal definition of refactoring and show its correspondence to the formal notion of information flow security (noninterference). This permits us to show security of refactoring patterns that have already been practically explored