177 research outputs found

    Experimental observation of photonic nodal line degeneracies in metacrystals

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    This is the final version of the article. Available from the publisher via the DOI in this record.Nodal line semimetals (NLS) are three-dimensional (3D) crystals that support band crossings in the form of one-dimensional rings in the Brillouin zone. In the presence of spin-orbit coupling or lowered crystal symmetry, NLS may transform into Dirac semimetals, Weyl semimetals, or 3D topological insulators. In the photonics context, despite the realization of topological phases, such as Chern insulators, topological insulators, Weyl, and Dirac degeneracies, no experimental demonstration of photonic nodal lines (NLs) has been reported so far. Here, we experimentally demonstrate NL degeneracies in microwave cut-wire metacrystals with engineered negative bulk plasma dispersion. Both the bulk and surface states of the NL metamaterial are observed through spatial Fourier transformations of the scanned near-field distributions. Furthermore, we theoretically show that the NL degeneracy can transform into two Weyl points when gyroelectric materials are incorporated into the metacrystal design. Our findings may inspire further advances in topological photonics.This work was financially supported by the European Research Council Consolidator Grant (TOPOLOGICAL). S.Z. acknowledges support from the Royal Society, the Wolfson Foundation, Horizon 2020 Action Project No. 734578 (D-SPA), the Leverhulme Trust (RPG-2012-674), and the Engineering and Physical Sciences Research Council (EP/ J018473/1). B.Y. acknowledges support from the China Scholarship Council (201306110041). A.P.H. acknowledges financial support from EPSRC of the United Kingdom (Grant No. EP/L015331/1). Near-field scanning data were collected by VNA controlled with xyz-stage at G31 at the Department of Physics and Astronomy, University of Exeter, United Kingdo

    Conformally coupled dark matter

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    Dark matter is obtained from a scalar field coupled conformally to gravitation; the scalar being a relict of Dirac's gauge function. This conformally coupled dark matter includes a gas of very light (m≈2.25×10−34eVm\approx 2.25\times 10^{-34} eV) neutral bosons having spin 0, as well as a time-dependent global scalar field, both pervading all of the cosmic space. The time-development of this dark matter in the expanding F-R-W universe is investigated, and an acceptable cosmological behaviour is obtained.Comment: LaTEX File 10 pages, no figure

    Radiatively Induced Neutrino Masses and Large Higgs-Neutrino Couplings in the Standard Model with Majorana Fields

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    The Higgs sector of the Standard Model with one right-handed neutrino per family is systematically analyzed. In a model with intergenerational independent mixings between families, we can account for very light neutrinos acquiring Majorana masses radiatively at the first electroweak loop level. We also find that in such a scenario the Higgs coupling to the light-heavy neutrinos and to the heavy-heavy ones may be remarkably enhanced with significant implications for the production of these heavy neutrinos at high energy colliders.Comment: Making the text of an old paper electronically availabl

    Ideal Weyl points and helicoid surface states in artificial photonic crystal structures (article)

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    The dataset associated with this article is located in ORE at: http://hdl.handle.net/10871/30744This is the author accepted manuscript. The final version is available from AAAS via the DOI in this record.Weyl points are the crossing points of linearly dispersing energy bands in the Brillouin zone of three-dimensional crystals. Weyl points provide the opportunity to explore a variety of intriguing phenomena such as topologically protected surface states and chiral anomalies. However the lack of an ideal Weyl system poses a serious limitation to the further development of Weyl physics and potential applications. Here, by experimentally characterizing a microwave photonic crystal comprised of a three dimensional array of saddle-shaped metallic coils, we observe ideal Weyl points which are related to each other through symmetry operations. Topological surface states exhibiting helicoidal structure in the energy-momentum space have also been demonstrated, which serve as a direct manifestation of the chiral nature of the Weyl points.This work was financially supported by ERC Consolidator Grant (Topological) and Leverhulme Trust (RPG-2012-674). S. Z. acknowledges support from the Royal Society and Wolfson Foundation. B. Y. acknowledges support from China Scholarship Council (201306110041). Y. X. acknowledges support from the National Natural Science Foundation of China (Grant No. 61490713). L. E. B. and A. P. H. acknowledge financial support from EPSRC of the United Kingdom (Grant No. EP/L015331/1). C.F. was supported by the National Key Research and Development Program of China under grant No. 2016YFA0302400 and by NSFC under grant No. 11674370. L.L. was supported by the National key R&D Program of China under Grant No. 2017YFA0303800, 2016YFA0302400 and by NSFC under Project No. 11721404

    Challenges and opportunities for ex-offender support through community nursing

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    This study was a qualitative case study underpinned by “The Silences Framework” aimed at mapping the ex-offender health pathway towards identifying “touch points” in the community for the delivery of a nurse-led intervention. Participants meeting the study inclusion criteria were quantitatively ranked based on poor health. Participants scoring the lowest and endorsing their ranking through a confirmation of a health condition were selected as cases and interviewed over 6 months. Individuals in the professional networks of offenders contextualized emergent themes. The study indicated that pre-release, offenders were not prepared in prison for the continuity in access to healthcare in the community. On release, reintegration preparation did not routinely enquire whether offenders were still registered with a general practitioner or had the agency to register self in the community. Participants identified the site of post-release supervision as the “touch point” where a nurse-led intervention could be delivere

    Carbon fiber masculinity: Disability and surfaces of homosociality

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    In this paper I am concerned with instances in which carbon fiber extends performances of masculinity that are attached to particular kinds of hegemonic male bodies. In examining carbon fiber as a prosthetic form of masculinity, I advance three main arguments. Firstly, carbon fiber can be a site of the supersession of disability that is affected through masculinized technology. Disability can be ‘overcome’ through carbon fiber. Disability is often culturally coded as feminine (Pedersen, 2001; Meeuf, 2009; Garland-Thompson 1997). Building on this cultural construction of disability as feminine, in and as a technology of masculine homosociality (Sedgwick, 1985), carbon fiber reproduced disability as feminine when carbon fiber prosthetic lower legs allowed Oscar Pistorius to compete in the non-disabled Olympic games. Secondly, I argue that carbon fiber can be a homosocial surface; that is, carbon fiber becomes both a surface extension of the self and a third party mediator in homosocial relationships, a surface that facilitates intimacy between men in ways that devalue femininity in both male and female bodies. I examine surfaces as material extensions of subjectivity, and carbon fiber surfaces as vectors of the cultural economies of masculine competition to which I refer. Thirdly, the case of Oscar Pistorius is exemplary of the masculinization of carbon fire, and the associated binding of a psychic attitude of misogyny and power to a form of violent and competitive masculine subjectivity. In this article I explore the affects, economies and surfaces of what I call ‘carbon fiber masculinity’ and discusses Pistorius’ use of carbon fiber, homosociality and misogyny as forms of protest masculinity through which he unconsciously attempted to recuperate his gendered identity from emasculating discourses of disability

    Trial Forge Guidance 1 : what is a Study Within A Trial (SWAT)?

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    Randomised trials are a central component of all evidence-informed health care systems and the evidence coming from them helps to support health care users, health professionals and others to make more informed decisions about treatment. The evidence available to trialists to support decisions on design, conduct and reporting of randomised trials is, however, sparse. Trial Forge is an initiative that aims to increase the evidence base for trial decision-making and in doing so, to improve trial efficiency.One way to fill gaps in evidence is to run Studies Within A Trial, or SWATs. This guidance document provides a brief definition of SWATs, an explanation of why they are important and some practical 'top tips' that come from existing experience of doing SWATs. We hope the guidance will be useful to trialists, methodologists, funders, approvals agencies and others in making clear what a SWAT is, as well as what is involved in doing one

    Prospectus, April 18, 1984

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    CHORAL UNION DEMANDING AND REWARDING; News Digest; Is your child part of the identi-child program?; Budding playwrights get chance to have work produced; PC Happenings: Parkland wins Automotive Contest, German Club annual Springfest, EMT workshop offered, Petitions available for Stu-Go, Stu-Go lacks quorum; Here Comes the Easter Bunny (or the Easter Hare?); Faces We Make; Former Prospectus entertainment writer: Alender services held; Strange things at the library; Only Food Service Management course in area: Sutton leads Food Service Management program; Criminal justice program well rounded; Running may increase protein need; Easter means Easter egg time; Second Wind hosts race; Did You Know...; Classifieds; Creative Corner...Especially for you!!: Recollections, She\u27s More than a Nurse, You are a corn-fed steak..., Memories..., A fire burns, AKTING??????????????..., Sometimes in their heed to tact..., Clouds, Disturb Not the Dead, Follow the Wind, I don\u27t know why I bother..., Innoncent Eyes, Please tell me what it is you want..., Running scared from yourself and tripped, babe..., Time Bomb, Don\u27t go away--Linger on..., Class, Raggedy Ann lay in the back of an old station wagon..., Too Late, To God; Ice Capades comes to town: Skaters say it\u27s hard work but well worth it; few surprises during Hollywood\u27s biggest night; \u27Queen\u27 film at Assembly Hall; Director shines in film; \u27Go-Go\u27s\u27 are back on track; \u27Weird Al\u27 hits big time; Fan Club to host film; Parkland College 1984 baseball roster; Cobra men lose two; 1984 Parkland Outdoor Track Bests; Sports Digest; Women lose twin bill; Prospectus survey resultshttps://spark.parkland.edu/prospectus_1984/1024/thumbnail.jp

    Motivations for seeking experimental treatment in Japan

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    In this article on innovative medical treatment for serious conditions in Japan we aim to revise two widespread notions: first, that people living with severe conditions are all waiting for a cure or are impatient to try out experimental treatment, in particular regenerative medicine. Showing that motivations for cure seeking are complex and linked to somatic identity, we argue that gaining a cure also means a new social normality, which for some people narrows the only normality that is meaningful to them; and, second, that people living with a serious (latent) condition necessarily define their lives as not normal in the light of normalization. People with a condition conceptualise normal life variously and multiply in the light of both individual and collective experiences. The two revisions are crucial to attempts at understanding what makes people seek experimental medicine. Comparing the narratives of people with four different conditions – spinal cord injury, Duchenne muscular dystrophy, Diabetes Mellitus type 1 and cardiovascular disease – it becomes clear that the difference between seeking treatment or not largely depends on somatic identities; rather than through notions of (ab)normality, it is more adequately understood in terms of the experience of somatic lacking and wholeness
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