7,177 research outputs found
Modified General Relativity and dark matter
Modified General Relativity (MGR) is the natural extension of General
Relativity (GR). MGR explicitly uses the smooth regular line element vector
field , which exists in all Lorentzian spacetimes, to
construct a connection-independent symmetric tensor that represents the
energy-momentum of the gravitational field. It solves the problem of the
non-localization of gravitational energy-momentum in GR, preserves the ontology
of the Einstein equation, and maintains the equivalence principle. The line
element field provides MGR with the extra freedom required to describe dark
energy and dark matter. An extended Schwarzschild solution for the matter-free
Einstein equation of MGR is developed, from which the Tully-Fisher relation is
derived, and the gravitational energy density is calculated. The mass of the
invisible matter halo of galaxy NGC 3198 calculated with MGR is identical to
the result obtained from GR using a dark matter profile. Although dark matter
in MGR is described geometrically, it has an equivalent representation as a
particle with the property of a vector boson or a pair of fermions; the
geometry of spacetime and the quantum nature of matter are linked together by
the unit line element covectors that belong to both the Lorentzian metric and
the spin-1 Klein-Gordon wave equation. The three classic tests of GR provide a
comparison of the theories in the solar system and several parts of the cosmos.
MGR provides the flexibility to describe inflation after the Big Bang and
galactic anisotropies.Comment: International Journal of Modern Physics
Integrative Research : Using Art to Research Art
© 2021 Informa UK Limited. This is the accepted manuscript version of book chapter which has been published in final form at https://doi.org/10.4324/9781003155676-20This chapter describes the importance of incorporating research into practice as the way in which a new profession generates evidence, develops research methodologies, and adapts practice as new and innovative approaches emerge from clinical experiences. The relational focus of researching therapy considers the therapist’s subjective experiences as being inextricably linked to the implicit and explicit experiences of the client in the therapy relationship. These experiences are seen as a reciprocal exchange of energy, affect, imagery, and imaginative responses that occur in the body and imagination of the therapist and are admissible as evidence and research data. The focus of research therefore places an equal emphasis on the reported experiences of the practitioner-researcher along with the experiences reported by the client, with both participants contributing to a collaborative account. This chapter contributes to constructing a research design that is based on the art experiences that form the foundation of art therapy. The framework aims to: a) incorporate practitioner-research as a central research paradigm; b) integrate therapists’ creative art making into reflective practice that can inform our supervisory and self-supervisory processes; c) elaborate how art-based methods record a range of dynamic art processes that emerge from creative clinical practice, and d) develop an embodied research framework.Peer reviewe
Precision fibre angle inspection for carbon fibre composite structures using polarisation vision
This paper evaluates the precision of polarisation imaging technology for the inspection of carbon fibre composite components. Specifically, it assesses the feasibility of the technology for fibre orientation measurements based on the premise that light is polarised by reflection from such anisotropically conductive surfaces. A recently commercialised Sony IMX250MZR sensor is used for data capture by using various lighting conditions. The paper shows that it is possible to obtain sub-degree accuracy for cured and dry woven and unidirectional materials in ideal conditions, which comprised dark field illumination. Indeed, in ideal conditions, the average relative angles can be measured to an accuracy of 0.1–0.2°. The results also demonstrate a precision of the order 1° for more general illumination, such as dome illumination and ambient lighting, for certain material type/lens combinations. However, it is also shown that the precision varies considerably depending on illumination, lens choice and material type, with some results having errors above 2°. Finally, a feasibility study into the inspection of three-dimensional components suggests that only limited application is possible for non-planar regions without further research. Nevertheless, the observed phenomena for such components are, at least, qualitatively understood based on physics theory
受有毒土壤污染的商业资产的价值评估
为了参加一次评估测试,这家银行的首席评估师拿到了一份关于拥有的不动产(REO)的财产卷宗。这是一栋已完工的、价值7万美元的办公楼,它所处的地理位置非常优越,但最近两年的出租率仅有50%,只达到预期出租率的一半。租金按市场价收取,但是办公楼群所在的街区由于没有什么名气,承租人在没有别的选择时才愿意承租这里的办公楼。在邻近的街区,同行竞争者的房屋空置率仅为12.5%。译者单位:厦门大学评估研究中心(361005
Effects of edge-stiffened web openings on the behaviour of cold-formed steel channel sections under compression
The use of cold-formed steel (CFS) channel sections are becoming popular as the load-carrying members in building structures, and such channel sections often include web openings for the ease of installation of services. Traditional web openings are normally punched, and are unstiffened which can restrict the size and spacing of web openings. Recently, a new generation of CFS channel sections with edge-stiffened web openings has been developed, and is widely used in New Zealand. However, no experimental investigation has been reported in the literature for such channel sections under compression. In this paper, a total of 75 results comprising 26 axial compression tests and 49 finite element analysis results are reported on the compression resistance of CFS channel sections with both edge-stiffened and unstiffened web openings. For comparison, channel sections without web openings were also tested. For all specimens, initial imperfections were measured using a laser scanner. A nonlinear elasto-plastic finite element model was also developed, and the results showed good agreement with the test results. A parametric study was conducted using the validated finite element model to investigate the effect of opening spacing and column length on compression resistance of channel sections. It is shown that for the case of a channel section having seven edge-stiffened web openings, the compression resistance increased by as much as 22%, compared to a plain channel section. For comparison, the same section having unstiffened web openings had a 20% reduction in compression resistance, compared to a plain channel section
Seven-year experience of a primary care antiretroviral treatment programme in Khayelitsha, South Africa.
OBJECTIVES: We report on outcomes after 7 years of a community-based antiretroviral therapy (ART) programme in Khayelitsha, South Africa, with death registry linkages to correct for mortality under-ascertainment. DESIGN: This is an observational cohort study. METHODS: Since inception, patient-level clinical data have been prospectively captured on-site into an electronic patient information system. Patients with available civil identification numbers who were lost to follow-up were matched with the national death registry to ascertain their vital status. Corrected mortality estimates weighted these patients to represent all patients lost to follow-up. CD4 cell count outcomes were reported conditioned on continuous virological suppression. RESULTS: Seven thousand, three hundred and twenty-three treatment-naive adults (68% women) started ART between 2001 and 2007, with annual enrolment increasing from 80 in 2001 to 2087 in 2006. Of 9.8% of patients lost to follow-up for at least 6 months, 32.8% had died. Corrected mortality was 20.9% at 5 years (95% confidence interval 17.9-24.3). Mortality fell over time as patients accessed care earlier (median CD4 cell count at enrolment increased from 43 cells/microl in 2001 to 131 cells/microl in 2006). Patients who remained virologically suppressed continued to gain CD4 cells at 5 years (median 22 cells/microl per 6 months). By 5 years, 14.0% of patients had failed virologically and 12.2% had been switched to second-line therapy. CONCLUSION: At a time of considerable debate about future global funding of ART programmes in resource-poor settings, this study has demonstrated substantial and durable clinical benefits for those able to access ART throughout this period, in spite of increasing loss to follow-up
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