1,014 research outputs found

    On massive gravitons in 2+1 dimensions

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    The Fierz-Pauli (FP) free field theory for massive spin 2 particles can be extended, in a spacetime of (1+2) dimensions (3D), to a generally covariant parity-preserving interacting field theory, in at least two ways. One is "new massive gravity" (NMG), with an action that involves curvature-squared terms. Another is 3D "bigravity", which involves non-linear couplings of the FP tensor field to 3D Einstein-Hilbert gravity. We review the proof of the linearized equivalence of both "massive 3D gravity" theories to FP theory, and we comment on their similarities and differences.Comment: 6 pages, to appear in the proceedings of the Spanish Relativity Meeting ERE2009, Bilbao; minor changes, reference adde

    Visions in monochrome: Families, marriage and the individualisation thesis

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    This paper takes issue with the way in which the individualisation thesis – in which it is assumed that close relationships have become tenuous and fragile - has become so dominant in ‘new’ sociological theorising about family life. Although others have criticised this thesis, in this paper the main criticism derives from empirical research findings carried out with members of transnational families living in Britain whose values and practices do not fit easily with ideas of individualisation. It is argued that we need a much more complex and less linear notion of how families change across generations and in time

    Quasilocal Energy in FRW Cosmology

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    This paper presents a calculation of the quasilocal energy of a generic FRW model of the universe. The results have the correct behavior in the small-sphere limit and vanish for the empty Milne universe. Higher order corrections are found when comparing these results to classical calculations of cosmological energy. This case is different from others in the literature chiefly in that it involves a non-stationary spacetime. This fact can be used to differentiate between the various formulations of quasilocal energy. In particular, the formulation due to Brown and York is compared to that of Epp. Only one of these is seen to have the correct classical limit.Comment: The article has been revised for publication in Classical and Quantum Gravity. All calculations remain unchanged. A discussion of Epp's formulation and additional references have been adde

    Progesterone resistance in endometriosis is modulated by the altered expression of microRNA-29c and FKBP4

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    Context: Endometriosis results in aberrant gene expression in the eutopic endometrium (EuE) and subsequent progesterone resistance. MicroRNA (miR) microarray data in a baboon model of endometriosis showed an increased expression of miR-29c. Objectives: To explore the role of miR-29c in progesterone resistance in a subset of women with endometriosis. Design: MiR-29c expression was analyzed in the endometrium of baboons and women with or without endometriosis. The role in progesterone resistance and decidualization was analyzed by transfecting human uterine fibroblast cells with miR-29c. Patients: Subjects diagnosed with deep infiltrative endometriosis (DIE) by transvaginal ultrasound with bowel preparation underwent surgical excision of endometriosis. Eutopic secretory endometrium was collected pre- and postoperatively. Women with normal EuE and without DIE served as controls. Results: Quantitative reverse transcription polymerase chain reaction demonstrated that miR-29c expression increased, while the transcript levels of its target, FK506-binding protein 4 (FKBP4), decreased in the EuE of baboons following the induction of endometriosis. FKBP4 messenger RNA and decidual markers were statistically significantly decreased in decidualized human uterine fibroblast cells transfected with a miR-29c mimic compared with controls. Human data corroborated our baboon data and demonstrated higher expression of miR-29c in endometriosis EuE compared with normal EuE. MiR-29c was significantly decreased in endometriosis EuE postoperatively compared with preoperative tissues, and FKBP4 showed an inverse trend following radical laparoscopic resection surgery. Conclusions: We demonstrate that miR-29c expression is increased in EuE of baboons and women with endometriosis, which might contribute to a compromised progesterone response by diminishing the levels of FKBP4. Resection of DIE is likely to reverse the progesterone resistance associated with endometriosis in women

    Novel polymer functionalization method for exposed-core optical fiber

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    We report on a one step functionalization process for optical fiber sensing applications in which a thin film ("50 nm) polymer doped with sensor molecules is applied to a silica exposed-core fiber. The method removes the need for surface attachment of functional groups, while integrating the polymer, silica and sensor molecule elements to create a distributed sensor capable of detecting an analyte of interest anywhere along the fiber’s length. We also show that the thin film coating serves a protective function, reducing deterioration in the transmission properties of the silica exposed-core fiber, but increasing lossRoman Kostecki, Heike Ebendorff-Heidepriem, Shahraam Afshar V., Grant McAdam, Claire Davis, and Tanya M. Monr

    Covariant coarse-graining of inhomogeneous dust flow in General Relativity

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    A new definition of coarse-grained quantities describing the dust flow in General Relativity is proposed. It assigns the coarse--grained expansion, shear and vorticity to finite-size comoving domains of fluid in a covariant, coordinate-independent manner. The coarse--grained quantities are all quasi-local functionals, depending only on the geometry of the boundary of the considered domain. They can be thought of as relativistic generalizations of simple volume averages of local quantities in a flat space. The procedure is based on the isometric embedding theorem for S^2 surfaces and thus requires the boundary of the domain in question to have spherical topology and positive scalar curvature. We prove that in the limit of infinitesimally small volume the proposed quantities reproduce the local expansion, shear and vorticity. In case of irrotational flow we derive the time evolution for the coarse-grained quantities and show that its structure is very similar to the evolution equation for their local counterparts. Additional terms appearing in it may serve as a measure of the backreacton of small-scale inhomogeneities of the flow on the large-scale motion of the fluid inside the domain and therefore the result may be interesting in the context of the cosmological backreaction problem. We also consider the application of the proposed coarse-graining procedure to a number of known exact solutions of Einstein equations with dust and show that it yields reasonable results.Comment: 17 pages, 5 figures. Version accepted in Classical and Quantum Gravity

    Afshar's Experiment does not show a Violation of Complementarity

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    A recent experiment performed by S. Afshar [first reported by M. Chown, New Scientist {\bf 183}, 30 (2004)] is analyzed. It was claimed that this experiment could be interpreted as a demonstration of a violation of the principle of complementarity in quantum mechanics. Instead, it is shown here that it can be understood in terms of classical wave optics and the standard interpretation of quantum mechanics. Its performance is quantified and it is concluded that the experiment is suboptimal in the sense that it does not fully exhaust the limits imposed by quantum mechanics.Comment: 6 pages, 6 figure

    One-Year Efficacy of Expanded Polytetrafluoroethylene Vascular Graft in Eighty-Three Hemodialysis Patients

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    <p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: small;"><span style="font-family: Times New Roman;"><strong><span style="mso-bidi-language: FA;">Purpose:</span></strong><span style="mso-bidi-language: FA;"> To evaluate the patency and efficacy of expanded Polytetrafluoroethylene (ePTFE) vascular graft in hemodialysis patients.</span></span></span></p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: small;"><span style="font-family: Times New Roman;"><strong><span style="mso-bidi-language: FA;">Materials and Methods:</span></strong><span style="mso-bidi-language: FA;"> In a prospective study from January 1999 to January 2001 at Sina hospital 41 patients underwent implantation of 6-mm vascular grafts and 42 underwent implantation of 8-mm grafts in order to make vascular assess for hemodialysis. They were followed up to 12 months, observing the complications. </span></span></span></p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: small;"><span style="font-family: Times New Roman;"><strong><span style="mso-bidi-language: FA;">Results:</span></strong><span style="mso-bidi-language: FA;"> Mean patients’ age was 52.2 years. Thirty-seven of them were females and 46 were males. Over a 12 months period of follow-up, 12 cases of graft infection (14.5%), 21 cases of thrombosis (25.3%), 7 cases with both complications (8.4%), and 1 case of pseudoaneurism (1.2%) were observed. One-year patency rate was 34.9%. Diabetes was the only factor associated with lower patency rate (27% versus 57%, p<0.05).</span></span></span></p><p class="MsoNormal" style="margin: 0cm 0cm 0pt;"><span style="font-size: small;"><span style="font-family: Times New Roman;"><strong><span style="mso-bidi-language: FA;">Conclusion:</span></strong><span style="mso-bidi-language: FA;"> ePTFE vascular graft seems to be an appropriate substitute for arteriovenous fistula as a vascular assess in hemodialysis patients. Educating patients and good care can decrease the rate of infection, thrombosis, and other complications, resulting in a better patency and lower morbidity rate.</span></span></span></p&gt
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