Metamaterials with conformational nonlinearity

Within a decade of fruitful development, metamaterials became a prominent area of research, bridging theoretical and applied electrodynamics, electrical engineering and material science. Being man-made structures, metamaterials offer a particularly useful playground to develop interdisciplinary concepts. Here we demonstrate a novel principle in metamaterial assembly which integrates electromagnetic, mechanical, and thermal responses within their elements. Through these mechanisms, the conformation of the meta-molecules changes, providing a dual mechanism for nonlinearity and offering nonlinear chirality. Our proposal opens a wide road towards further developments of nonlinear metamaterials and photonic structures, adding extra flexibility to their design and control

Magnetoelastic nonlinear metamaterials

We introduce the concept of magnetoelastic metamaterials with electromagnetic properties depending on elastic deformation. We predict a strong nonlinear and bistable response of such metamaterials caused by their structural reshaping in response to the applied electromagnetic field. In addition, we demonstrate experimentally the feasibility of the predicted effect.Comment: 4 pages, 5 figure

Nonlinear Localization in Metamaterials

Metamaterials, i.e., artificially structured ("synthetic") media comprising weakly coupled discrete elements, exhibit extraordinary properties and they hold a great promise for novel applications including super-resolution imaging, cloaking, hyperlensing, and optical transformation. Nonlinearity adds a new degree of freedom for metamaterial design that allows for tuneability and multistability, properties that may offer altogether new functionalities and electromagnetic characteristics. The combination of discreteness and nonlinearity may lead to intrinsic localization of the type of discrete breather in metallic, SQUID-based, and ${\cal PT}-$symmetric metamaterials. We review recent results demonstrating the generic appearance of breather excitations in these systems resulting from power-balance between intrinsic losses and input power, either by proper initialization or by purely dynamical procedures. Breather properties peculiar to each particular system are identified and discussed. Recent progress in the fabrication of low-loss, active and superconducting metamaterials, makes the experimental observation of breathers in principle possible with the proposed dynamical procedures.Comment: 19 pages, 14 figures, Invited (Review) Chapte

The study on the outsourcing of Taiwan's hospitals: a questionnaire survey research

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to assess the outsourcing situation in Taiwanese hospitals and compares the differences in hospital ownership and in accreditation levels.</p> <p>Methods</p> <p>This research combined two kinds of methods: a questionnaire survey and the in-depth interview to two CEOs of the sample hospitals. One hospital is not-for-profit, while the other is a public hospital and the research samples are from the hospital data from Taiwan's 2005 to 2007 Department of Health qualifying lists of hospital accreditation. The returned questionnaires were analyzed with STATISTICA^®7.1 version software.</p> <p>Results</p> <p>The results for non-medical items showed medical waste and common trash both have the highest rate (94.6 percent) of being outsourced. The gift store (75 percent) and linen (73 percent) follow close behind, while the lowest rate of outsourcing is in utility maintenance (13.5 percent). For medical items, the highest rate of outsourcing is in the ambulance units (51.4 percent), while the hemodialysis center follows close behind with a rate of 50 percent. For departments of nutrition, pharmacy, and nursing however, the outsourcing rate is lower than 3 percent. This shows that Taiwan's hospitals are still conservative in their willingness to outsource for medical items. The results of the satisfaction paired t-test show that the non-medical items have a higher score than the medical items. The factor analysis showed the three significant factors in of non medical items' outsourcing are "performance", "finance", and "human resource". For medical items, the two factors are "operation" and satisfaction". To further exam the factor validity and reliability of the satisfaction model, a confirmative factor analysis (CFA) was conducted using structure equation modeling (SEM) method and found the model fitting well.</p> <p>Conclusion</p> <p>Hospitals, especially for public hospitals, can get benefits from outsourcing to revive the full-time-equivalent and human resource limitation.</p

First Neutrino Observations from the Sudbury Neutrino Observatory

The first neutrino observations from the Sudbury Neutrino Observatory are presented from preliminary analyses. Based on energy, direction and location, the data in the region of interest appear to be dominated by 8B solar neutrinos, detected by the charged current reaction on deuterium and elastic scattering from electrons, with very little background. Measurements of radioactive backgrounds indicate that the measurement of all active neutrino types via the neutral current reaction on deuterium will be possible with small systematic uncertainties. Quantitative results for the fluxes observed with these reactions will be provided when further calibrations have been completed.Comment: Latex, 7 pages, 10 figures, Invited paper at Neutrino 2000 Conference, Sudbury, Canada, June 16-21, 2000 to be published in the Proceeding

Subwavelength anti-diffracting beams propagating over more than 1,000 Rayleigh lengths

Propagating light beams with widths down to and below the optical wavelength require bulky large-aperture lenses and remain focused only for micrometric distances. Here, we report the observation of light beams that violate this localization/depth- of-focus law by shrinking as they propagate, allowing resolution to be maintained and increased over macroscopic propagation lengths. In nanodisordered ferroelectrics we observe a non-paraxial propagation of a sub-micrometre-sized beam for over 1,000 diffraction lengths, the narrowest visible beam reported to date. This unprecedented effect is caused by the nonlinear response of a dipolar glass, which transforms the leading opticalwave equation into a Klein-Gordon-type equation that describes a massive particle field. Our findings open the way to high-resolution optics over large depths of focus, and a route to merging bulk optics into nanodevices

Diagnosing problems of fine sediment delivery and transfer in a lowland catchment

This paper is a product of research conducted within the REFORM collaborative project funded by the European Union Seventh Framework Programme under grant agreement 282656

Does parallel item content on WOMAC's Pain and Function Subscales limit its ability to detect change in functional status?

BACKGROUND: Although the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) is considered the leading outcome measure for patients with osteoarthritis of the lower extremity, recent work has challenged its factorial validity and the physical function subscale's ability to detect valid change when pain and function display different profiles of change. This study examined the etiology of the WOMAC's physical function subscale's limited ability to detect change in the presence of discordant changes for pain and function. We hypothesized that the duplication of some items on the WOMAC's pain and function subscales contributed to this shortcoming. METHODS: Two eight-item physical function scales were abstracted from the WOMAC's 17-item physical function subscale: one contained activities and themes that were duplicated on the pain subscale (SIMILAR-8); the other version avoided overlapping activities (DISSIMILAR-8). Factorial validity of the shortened measures was assessed on 310 patients awaiting hip or knee arthroplasty. The shortened measures' abilities to detect change were examined on a sample of 104 patients following primary hip or knee arthroplasty. The WOMAC and three performance measures that included activity specific pain assessments – 40 m walk test, stair test, and timed-up-and-go test – were administered preoperatively, within 16 days of hip or knee arthroplasty, and at an interval of greater than 20 days following the first post-surgical assessment. Standardized response means were used to quantify change. RESULTS: The SIMILAR-8 did not demonstrate factorial validity; however, the factorial structure of the DISSIMILAR-8 was supported. The time to complete the performance measures more than doubled between the preoperative and first postoperative assessments supporting the theory that lower extremity functional status diminished over this interval. The DISSIMILAR-8 detected this deterioration in functional status; however, no significant change was noted for the SIMILAR-8. The WOMAC pain scale demonstrated a slight reduction in pain and the performance specific pain measures did not reflect a change in pain. All measures showed substantial improvement over the second assessment interval. CONCLUSIONS: These findings support the hypothesis that activity overlap on the pain and function subscales plays a causal role in limiting the WOMAC physical function subscale's ability to detect change