250 research outputs found

    Thiemann transform for gravity with matter fields

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    The generalised Wick transform discovered by Thiemann provides a well-established relation between the Euclidean and Lorentzian theories of general relativity. We extend this Thiemann transform to the Ashtekar formulation for gravity coupled with spin-1/2 fermions, a non-Abelian Yang-Mills field, and a scalar field. It is proved that, on functions of the gravitational and matter phase space variables, the Thiemann transform is equivalent to the composition of an inverse Wick rotation and a constant complex scale transformation of all fields. This result holds as well for functions that depend on the shift vector, the lapse function, and the Lagrange multipliers of the Yang-Mills and gravitational Gauss constraints, provided that the Wick rotation is implemented by means of an analytic continuation of the lapse. In this way, the Thiemann transform is furnished with a geometric interpretation. Finally, we confirm the expectation that the generator of the Thiemann transform can be determined just from the spin of the fields and give a simple explanation for this fact.Comment: LaTeX 2.09, 14 pages, no figure

    Women's reproductive rights in the inter-American system of human rights: conclusions from the Field, June - September 2014

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    The Inter-American System of Human Rights has proven to be a forum for the advancement of women’s reproductive rights in the Inter-American region. However, the Inter-American System faces significant challenges in promoting structural transformative change that enables women’s enjoyment of their reproductive health rights. This report examines three reproductive rights cases from the Inter- American Commission on Human Rights and the Inter-American Court of Human Rights: María Mamerita Mestanza Chávez v. Peru; Paulina Ramirez Jacinto v. Mexico; and Artavia Murillo et al. v. Costa Rica. In the summer of 2014, interviews were conducted with representatives in each of the case study countries, with the objective of the research being two-fold: (1) to understand how each of the cases developed, and the subsequent challenges and advancements; and (2) to learn from these cases in order to suggest recommendations for how actors can make better use of the Inter-American System as one of several avenues for protecting, promoting and fulfilling women’s reproductive rights. The report first discusses challenges in implementing women’s reproductive health rights, and then explores how the Inter-American System can strengthen its work on women’s reproductive health rights

    Phenomenological description of quantum gravity inspired modified classical electrodynamics

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    We discuss a large class of phenomenological models incorporating quantum gravity motivated corrections to electrodynamics. The framework is that of electrodynamics in a birefringent and dispersive medium with non-local constitutive relations, which are considered up to second order in the inverse of the energy characterizing the quantum gravity scale. The energy-momentum tensor, Green functions and frequency dependent refraction indices are obtained, leading to departures from standard physics. The effective character of the theory is also emphasized by introducing a frequency cutoff. The analysis of its effects upon the standard notion of causality is performed, showing that in the radiation regime the expected corrections get further suppressed by highly oscillating terms, thus forbiding causality violations to show up in the corresponding observational effects.Comment: 14 pages, to be published in Obregon Festschrift 2006, Gen. Rel. and Gra

    Positive predictive value of ERBB2 copy number gain by tissue or circulating tumor DNA next-generation sequencing across advanced cancers

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    BACKGROUND: The correlation of ERBB2 copy number gain (CNG) from tissue or circulating tumor DNA (ctDNA) by next-generation sequencing (NGS) with standard HER2 tissue evaluation is not well understood. MATERIALS AND METHODS: We retrospectively identified patients with ERBB2 CNG on commercial NGS. We described their clinical-pathologic features and calculated the positive predictive value (PPV) of ERBB2 CNG by NGS for HER2-positivity by IHC and FISH testing. RESULTS: 176 patients had NGS revealing an ERBB2 CNG (112 by tumor tissue and 91 by ctDNA). The cancer subtypes with the most cases with ERBB2 CNG by NGS were breast ( CONCLUSIONS: ERBB2 CNG by NGS is detected in numerous malignancies for which HER2 testing is not standard. Detection of ERBB2 CNG by tissue NGS and ctDNA has a high PPV for true HER2-positivity by standard IHC and/or FISH testing in breast cancer

    Promoting sustainable agricultural intensification and crowdsourcing plot information

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    Provision of adequate and timely information to farmers on the ground means optimizing crop production decisions, reducing costs and eliminating adverse effects of overuse of agricultural inputs, e.g. fertilizer. AgroTutor aims to support farmers across Mexico with benchmarking information, including historical and potential yield on the area where the plot is located, historical costs, income and profit as well as agronomical recommendations. Location and limits of parcels can be saved, and agronomical activities including costs, pictures and videos can be then added to document the cropping system

    Sustainable electrochemical energy storage devices using natural bast fibres

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    Naturally abundant materials play a crucial role in the development of sustainable electrochemical energy storage (EES) devices including batteries and supercapacitors (SCs). This is due to limited available resources with regard to energy storage materials, and the environmental pollution produced the toxic materials utilized in conventional EESs. In the current review, development in the field of natural bast fibres (jute, flax, hemp, kenaf) based EESs performances is highlighted. This review emphasizes methods such as the direct use of modified fibres and activated carbon from biomass for the design of EES devices. Activated fibres were developed using both physical and chemical activation methods. Key challenges including active electrode materials preparation, capacitive retention, and the implementation of the fiber based EES devices are critically discussed. Furthermore, the recent surge in the use of wearables and portable technologies that demand further development of flexible/non-flexible EES devices are also explored. Future trends and perspectives on materials development, power management interface, recycling, biodegradability and circular economy are also addressed. It is concluded that the development of new renewable energy systems using bast fibres has many remarkable advances in device performance. For this, an innovative approach is required to develop high energy density bast fibre based sustainable EES devices which will be potentially implemented for clean energy solutions
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