Elastic metamaterials with simultaneously negative effective shear modulus and mass density

We propose a type of elastic metamaterial comprising fluid-solid composite inclusions which can possess negative shear modulus and negative mass density over a large frequency region. Such a solid metamaterial has a unique elastic property that only transverse waves can propagate with a negative dispersion while longitudinal waves are forbidden. This leads to many interesting phenomena such as negative refraction, which is demonstrated by using a wedge sample, and a significant amount of mode conversion from transverse waves to longitudinal waves that cannot occur on the interface of two natural solids

Active Matrix Flat Panel Bio-Medical X-ray Imagers

This work investigates the design, system integration, optimization, and evaluation of amorphous silicon (a-Si:H) active matrix flat panel imagers (AMFPI) for bio-medical applications. Here, two hybrid active pixel sensor (H-APS) designs are introduced that improve the dynamic range while maintaining the desirable attributes of high speed and low noise readout. Also presented is a systematic approach for noise analysis of thin film transistors (TFT) and pixel circuits in which circuit analysis techniques and TFT noise models are combined to evaluate circuit noise performance. We also explore different options of system integration and present measurement results of a high fill-factor (HFF) array with segmented photodiode

Multiple-Planet Scattering and the Origin of Hot Jupiters

Exoplanets show a pile-up of Jupiter-size planets in orbits with a 3-day period. A fraction of these hot Jupiters have retrograde orbits with respect to the parent star's rotation. To explain these observations we performed a series of numerical integrations of planet scattering followed by the tidal circularization. We considered planetary systems having 3 and 4 planets initially. We found that the standard Kozai migration is an inefficient mechanism for the formation of hot Jupiters. Our results show the formation of two distinct populations of hot Jupiters. The inner population of hot Jupiters with semimajor axis a < 0.03 AU formed in the systems where no planetary ejections occurred. This group contained a significant fraction of highly inclined and retrograde orbits, with distributions largely independent of the initial setup. However, our follow-up integrations showed that this populations was transient with most planets falling inside the Roche radius of the star in <1 Gyr. The outer population of hot Jupiters formed in systems where at least one planet was ejected. This population survived the effects of tides over >1 Gyr. The semimajor axis distribution of Population II fits nicely the observed 3-day pile-up. The inclination distribution of the outer hot planets depends on the number of planets in the initial systems and the 4-planet case showed a larger proportion (up to 10%), and a wider spread in inclination values. As the later results roughly agrees with observations, this may suggest that the planetary systems with observed hot Jupiters were originally rich in the number of planets, some of which were ejected. In a broad perspective, our work therefore hints on an unexpected link between the hot Jupiters and recently discovered free floating planets.Comment: submitted to Ap

Employee empowerment in international tourist hotels in Taiwan: A cultural perspective.

Empowerment in the hospitality industry is often regarded as a means to improve service quality and customer satisfaction by involving frontline employees with a focus on the employee-guest encounter. Because of the notion of empowerment many international hotel chains companies try to adopt and implement empowerment and transfer empowerment management practice to their hotels worldwide. However empowerment theory has barely addressed the implications of applying empowerment in a cross-cultural context (Klidas, 2001). This thesis explores in what way and to what extent national cultural value orientations influence individual behaviours for empowerment policy and practice through cases studies of three international tourist hotels in Taiwan. The study's approach involved developing a conceptual framework of issues related to employee empowerment implementation. The investigation is based on the way that individual employees and managers give their personal views and experiences with regard to empowerment and look at the causes of any gaps between the empowerment rhetoric and practice. Relevant primary data was collected through semi-structured interviews and document analysis. The study adopted an inductive approach to evaluate the implication of the research's empirical findings to understand better national cultural value orientations influence individual behaviours. The results highlight the Taiwanese cultural value of group harmony orientation influence individual behaviour that may affect people's perception of relationship between managers and employees and how business should be operated challenging empowerment implementation. The contribution of this research is to our understanding of national cultural values have an impact on empowerment implementation and to the theory of the cultural relativity of empowerment

A survey of boat-based recreational fishing in inner Shark Bay 2016/17

Monitoring the temporal and spatial variability in recreational fishing provides necessary information for assessing resource sustainability, monitoring resource allocation and informing fisheries management. This is particularly important in inner Shark Bay because recreational fishing occurs in a World Heritage Area and Marine Park. The majority of boat-based recreational fishers in inner Shark Bay target Pink Snapper (Chrysophrys auratus) and three genetically distinct stocks of this species occur in the Denham Sound, Eastern Gulf and Freycinet Estuary Management Zones

Slab Control on the Northeastern Edge of the Mid-Pacific LLSVP near Hawaii

At the core‐mantle boundary, most observed ultralow velocity zones (ULVZs) cluster along the edges of the large low shear velocity provinces (LLSVPs) and provide key information on the composition, dynamics, and evolution of the lower mantle. However, their detailed structure near slab‐like structures beneath the mid‐Pacific remains particularly challenging because of the lack of station coverage. While most studies of ULVZs concentrate on SKS‐complexity, here we report on the multipathing of ScS, which expands the sampling for ULVZs. We find the strongest multipathing along a ULVZ patch located just south of Hawaii and the far northeastern edge of the LLSVP, in a zone ~200 km in width and extending 600 km southward. The anomalous ScS travel times and distorted S_(diff) waveforms further reveal patches interrupted by observed enhanced D″ indicative of slab‐debris influence on the complexity of the northeastern boundary of the mid‐Pacific LLSVP

Harnessing the Power of Digital Platforms to Accelerate Adoption Rates of Emerging Technologies and Innovations

Excerpt from the Proceedings of the Nineteenth Annual Acquisition Research SymposiumThe recent Overmatch championed Artificial Intelligence and Networks (AINet) Advanced Naval Technology Exercise (ANTX) demonstrated an alternative all-digital ANTX format enabled by integrated Rapid Innovation Labs (iRILs). This resulted in shortened ANTX planning and execution timelines, increased focus on technologies of interest, earlier integration into naval architectures, sharing of relevant operational data with participants, and meaningful feedback to developers throughout integration phases, informing research and development (R&D) and program acquisitions. An iRIL is a digital environment and an acquisition tool used to address priority Fleet needs, evaluate technologies and prototypes, and inform and influence external partner R&D investments. An all-digital iRIL can facilitate faster, smaller cycles of iterative experimentation of component technologies of interest within representative Fleet architectures and simulated operational environments. Future applications of iRILs could fundamentally change the way we acquire systems. The use of open competitive events such as an ANTX Prize Challenge could yield component level, containerized technologies of interest that are matured throughout the event process and can be assessed as well-behaved. Such well-behaved software containers or component technologies may enter the Overmatch Software Armory (OSA) or Live, Virtual, and Constructive (LVC) pipelines, achieving rapid authorities to operate (ATO), cycling to a ship within days.Approved for public release; distribution is unlimited

Virus-induced gene complementation reveals a transcription factor network in modulation of tomato fruit ripening

Plant virus technology, in particular virus-induced gene silencing, is a widely used reverse- and forward-genetics tool in plant functional genomics. However the potential of virus technology to express genes to induce phenotypes or to complement mutants in order to understand the function of plant genes is not well documented. Here we exploit Potato virus X as a tool for virus-induced gene complementation (VIGC). Using VIGC in tomato, we demonstrated that ectopic viral expression of LeMADS-RIN, which encodes a MADS-box transcription factor (TF), resulted in functional complementation of the non-ripening rin mutant phenotype and caused fruits to ripen. Comparative gene expression analysis indicated that LeMADS-RIN up-regulated expression of the SBP-box (SQUAMOSA promoter binding protein-like) gene LeSPL-CNR, but down-regulated the expression of LeHB-1, an HD-Zip homeobox TF gene. Our data support the hypothesis that a transcriptional network may exist among key TFs in the modulation of fruit ripening in tomato

Electromagnetic force density in dissipative isotropic media

We derive an expression for the macroscopic force density that a narrow-band electromagnetic field imposes on a dissipative isotropic medium. The result is obtained by averaging the microscopic form for Lorentz force density. The derived expression allows us to calculate realistic electromagnetic forces in a wide range of materials that are described by complex-valued electric permittivity and magnetic permeability. The three-dimensional energy-momentum tensor in our expression reduces for lossless media to the so-called Helmholtz tensor that has not been contradicted in any experiment so far. The momentum density of the field does not coincide with any well-known expression, but for non-magnetic materials it matches the Abraham expression

Evaporation of Jupiter like planets orbiting extreme horizontal branch stars

We study the evaporation of planets orbiting close to hot (extreme) horizontal branch (EHB) stars. These planets survived the common envelope phase inside the envelope of the reg giant star progenitor. We find that Jupiter-like planets orbiting within 10Ro from an EHB star suffers a non-negligible mass-loss during their 10^8 yr evolution on the horizontal branch. The evaporated gas is ionized and becomes a source of Balmer lines. Such planets might be detected by the periodic variation of the Doppler shift of the Balmer lines.Comment: Accepted to MNRA