Optimized sympathetic cooling of atomic mixtures via fast adiabatic strategies

We discuss fast frictionless cooling techniques in the framework of sympathetic cooling of cold atomic mixtures. It is argued that optimal cooling of an atomic species - in which the deepest quantum degeneracy regime is achieved - may be obtained by means of sympathetic cooling with another species whose trapping frequency is dynamically changed to maintain constancy of the Lewis-Riesenfeld adiabatic invariant. Advantages and limitations of this cooling strategy are discussed, with particular regard to the possibility of cooling Fermi gases to a deeper degenerate regime.Comment: 5 pages, 3 figure

Value adding and supply chain development for fisheries and aquaculture products in Fiji, Samoa and Tonga: supply chain for sea grapes (Caulerpa racemosa) in Fiji

Introduction: The aim of this survey was to gather information for the supply chain analysis of Caulerpa racemosa in Fiji. Sites were identified from preliminary market surveys conducted in 2010. Site visits were carried out during July, October and November, 2011. The areas visited included, Yasawa Islands (Gunu), Sigatoka (Lomawai, Vusama), Rakiraki (Namiumada, Navolau), Tavua (Vatutavui), Labasa (Vuniuto, Sasake, Lakeba) and Savusavu (Dromoniku). Some villages that supplied nama were not visited due to time constraints and a village funeral. These included Somosomo and Nasoqo in Yasawa, Naweni in Savusavu, Vatulele Island in Serua, Nasosivi, Nabubu and Drua Drua in Labasa (Figure 1). Anecdotal information from shipping personnel, fisheries officers and market vendors suggested that Lomaiviti (Nairai and Batiki islands) and Tailevu also supplied nama occasionally, depending on availability of transport

Strategic Network Formation with Attack and Immunization

Strategic network formation arises where agents receive benefit from connections to other agents, but also incur costs for forming links. We consider a new network formation game that incorporates an adversarial attack, as well as immunization against attack. An agent's benefit is the expected size of her connected component post-attack, and agents may also choose to immunize themselves from attack at some additional cost. Our framework is a stylized model of settings where reachability rather than centrality is the primary concern and vertices vulnerable to attacks may reduce risk via costly measures. In the reachability benefit model without attack or immunization, the set of equilibria is the empty graph and any tree. The introduction of attack and immunization changes the game dramatically; new equilibrium topologies emerge, some more sparse and some more dense than trees. We show that, under a mild assumption on the adversary, every equilibrium network with $n$ agents contains at most $2n-4$ edges for $n\geq 4$. So despite permitting topologies denser than trees, the amount of overbuilding is limited. We also show that attack and immunization don't significantly erode social welfare: every non-trivial equilibrium with respect to several adversaries has welfare at least as that of any equilibrium in the attack-free model. We complement our theory with simulations demonstrating fast convergence of a new bounded rationality dynamic which generalizes linkstable best response but is considerably more powerful in our game. The simulations further elucidate the wide variety of asymmetric equilibria and demonstrate topological consequences of the dynamics e.g. heavy-tailed degree distributions. Finally, we report on a behavioral experiment on our game with over 100 participants, where despite the complexity of the game, the resulting network was surprisingly close to equilibrium.Comment: The short version of this paper appears in the proceedings of WINE-1

Field assisted processing of 3D printed ceramics

Advanced ceramic products for highly demanding applications in electronics, energy, healthcare and defence sectors require densification/sintering, a high temperature process (~1000–2000oC) that in industry can take days. The amount of energy needed, and CO2 emitted, is therefore very significant. Conventional processing of these functional devices/components are often plagued by interfacial issues, unwanted grain growth and limitations of co-firing dissimilar materials. Thus, rapid and efficient sintering methods such as SPS, Microwave Assisted Sintering (MAS) and Flash Sintering (FS) are continuously being developed. These approaches referred as Field Assisted Sintering Techniques (FAST) use an external field that was demonstrated to have a positive effect on densification. For example, the FS method, for reasons that are far from fully understood, has yielded full densification in very short periods (5 s) at very low furnace temperatures (850oC) for zirconia, and at a surprisingly low temperature of 325oC for Co2MnO4 spinel ceramics. The associated time and energy advantage is estimated to be staggering, as well as the ability to tailor the microstructure. In this talk, we will have a closer look at MAS and FS methods– one a well-established and the other a newly emerging densification method. The MAS method can be suitable for the processing of various simple and complex shaped engineering components, the early use of FS method was restricted to dog-bone shaped ceramic specimens – that are both difficult to make and do not have much industrial applicability. However, the recent developments have demonstrated that FS can also be used to sinter different sample shapes. We investigated the feasibility of sintering of 3D printed ultra-low loss 5G microwave dielectrics, YSZ/ZTA biomedical components using MS and FS methods along with measurements of shrinkage and thermal mapping. This talk will review these developments on FS along with the operative mechanisms in comparison with MAS

Conditions for the Quantum to Classical Transition: Trajectories vs. Phase Space Distributions

We contrast two sets of conditions that govern the transition in which classical dynamics emerges from the evolution of a quantum system. The first was derived by considering the trajectories seen by an observer (dubbed the ``strong'' transition) [Bhattacharya, et al., Phys. Rev. Lett. 85: 4852 (2000)], and the second by considering phase-space densities (the ``weak'' transition) [Greenbaum, et al., Chaos 15, 033302 (2005)]. On the face of it these conditions appear rather different. We show, however, that in the semiclassical regime, in which the action of the system is large compared to $\hbar$, and the measurement noise is small, they both offer an essentially equivalent local picture. Within this regime, the weak conditions dominate while in the opposite regime where the action is not much larger than Planck's constant, the strong conditions dominate.Comment: 8 pages, 2 eps figure

Parameter scaling in the decoherent quantum-classical transition for chaotic systems

The quantum to classical transition has been shown to depend on a number of parameters. Key among these are a scale length for the action, $\hbar$, a measure of the coupling between a system and its environment, $D$, and, for chaotic systems, the classical Lyapunov exponent, $\lambda$. We propose computing a measure, reflecting the proximity of quantum and classical evolutions, as a multivariate function of $(\hbar,\lambda,D)$ and searching for transformations that collapse this hyper-surface into a function of a composite parameter $\zeta = \hbar^{\alpha}\lambda^{\beta}D^{\gamma}$. We report results for the quantum Cat Map, showing extremely accurate scaling behavior over a wide range of parameters and suggest that, in general, the technique may be effective in constructing universality classes in this transition.Comment: Submitte

Classifying Network Intrusions: A Comparison of Data Mining Methods

Network intrusion is an increasingly serious problem experienced by many organizations. In this increasingly hostile environment, networks must be able to detect whether a connection attempt is legitimate or not. The ever-changing nature of these attacks makes them difficult to detect. One solution is to use various data mining methods to determine if the network is being attacked. This paper compares the performance of two data mining methods— i.e., a standard artificial neural network (ANN) and an ANN guided by genetic algorithm (GA)— in classifying network connections as normal or attack. Using connection data drawn from a simulated US Air Force local area network each method was used to construct a predictive model. The models were then applied to validation data and the results were compared. The ANN guided by GA (90.67% correct classification) outperformed the standard ANN (81.75% correct classification) significantly, indicating the superiority of GAbased ANN

Annotated bibliography on the current status and product development of Tilapia in Fiji, Samoa and Tonga

Tilapia, named the 'food fish of the 21st century', is one of the most cultured freshwater fish in the world, farmed in more than 100 countries (Norman-Lopez & Bjorndal, 2009). A hardy and prolific, fast-growing tropical fish, it requires low input during grow-out periods and can be farmed successfully on any level, from extensive to intensive culture in ponds, tanks or raceways (Fitzsimmons, 2006). It is disease resistant, tolerant of poor water quality, can eat a wide range of food types and be cultured in fresh or brackish water. Chemicals and antibiotics are not necessary for commercial farming (Fitzsimmons, 2008). Introduced into the Pacific Islands region in the 1950s, tilapia became a commodity for culture due to its low-cost and success in other regions. For Fiji and Samoa, tilapia was for human consumption and as potential pig feed (Costa- Pierce, 1998), although in Tonga it became an unsuccessful attempt to control mosquitoes. Fiji and Papua New Guinea both have policies of government support for tilapia farming in rural areas. Household-scale tilapia farming is common in the Pacific but medium-scale enterprises are now on the increase (Pickering, T. 2009). Efforts in value adding of tilapia have been minimal in the Pacific (spc.int). Tilapia is mostly sold live or fresh in bundles but interestingly in Papua New Guinea, cooked tilapia (fried) is sold on the roadsides (Ponia & Mobiha, 2002). Simple village level post harvest processing, such as smoking may exist in some countries (spc.int) but proper documentation is absent. This annotated bibliography was developed as part of the Scoping Study for PARDI 2010/002 prepared by South, G.R., et al., 2011. Scoping study for Tilapia (Oreochromis sp.). Suva: Institute of Marine Resources, School of Marine Studies, FSTE, USP. References are specific to the Pacific or are directly related to the project. Most of the references are annotated

Global change and coral reef management capacity in the Pacific: engaging scientists and policy makers in Fiji, Samoa, Tuvalu and Tonga: general background dossier

Executive Summary: Sustaining healthy coral reefs is vital to the livelihoods of the people of the Pacific Islands. Global change is having increasing impacts on Pacific coral reefs, leading to increased vulnerability of coastal communities (Reefs at Risk Revisited, 2011. World Resources Institute). Integrating global change into policies across various national government sectors and then, translating this into actions that lead to sustainable management of coastal ecosystems is an enormous challenge. The project sought to address this through face-to-face dialogue between reef experts and government personnel responsible for coral reef management policies. It aimed to strengthen science-policy interaction and linkages and empower policy-makers to make informed decisions. The project targeted four countries all heavily dependent on their coral reefs: Fiji, Samoa, Tonga and Tuvalu. Using the most recent information available on the sustainable management of coral reefs, the project brought Pacific Leaders together with scientists and experts so that they could be apprised of the impacts of global change and of those factors that are affecting the health of their coral reefs. For each country this detailed national dossier was prepared by the project team in consultation with the countries, leading into two-day workshops. The dossier includes a series of issues (including gaps) pertinent to each country which were used in the development of national coral reef plans. About a year later, countries were revisited to review and measure the progress achieved on recommendations on fisheries, marine managed areas, global change and multi-sectoral, multi stakeholder consultations. Although progress varied in the four countries, it was evident that collaboration between relevant government departments needed to be improved and that there was a need for the establishment and implementation of management systems that will be on-going and self financing given the resources available. Workshops were held between June and August 2010, in which a total of some 130 senior officials from Fiji, Samoa, Tuvalu and Tonga attended. The workshops identified priority actions for coral reef management. It was found that all four countries had in place, or are developing, appropriate policies for the sustainable management of their coral reefs, taking into account the anticipated impacts of global change. All lacked, however, an overarching policy and the necessary human resources and expertise required for implementation. This situation highlights the dilemma faced by the small Pacific countries responsible for the custodianship of the unique biodiversity of their reefs. In follow-up discussions two countries (Samoa and Tuvalu), requested our assistance in the development of their National Ocean Policies which would provide the needed over-arching policy and national commitment to sustainable coral reef management. The Institute of Marine Resources has the expertise to do this but would require the necessary funding. The project provided a model for interaction between scientists and policy makers that could be readily extended to other Pacific Island countries or, for that matter, to other island states where the sustainable management of coral reefs is of vital importance for the conservation of valuable reef resources, and for maintaining the livelihoods of people

Advanced parametrical modelling of 24 GHz radar sensor IC packaging components

This paper deals with the development of an advanced parametrical modelling concept for packaging components of a 24 GHz radar sensor IC used in automotive driver assistance systems. For fast and efficient design of packages for system-in-package modules (SiP), a simplified model for the description of parasitic electromagnetic effects within the package is desirable, as 3-D field computation becomes inefficient due to the high density of conductive elements of the various signal paths in the package. By using lumped element models for the characterization of the conductive components, a fast indication of the design's signal-quality can be gained, but so far does not offer enough flexibility to cover the whole range of geometric arrangements of signal paths in a contemporary package. This work pursues to meet the challenge of developing a flexible and fast package modelling concept by defining <i>parametric</i> lumped-element models for all basic signal path components, e.g. bond wires, vias, strip lines, bumps and balls