A Note on Lie-Lorentz Derivatives

The definition of ``Lie derivative'' of spinors with respect to Killing vectors is extended to all kinds of Lorentz tensors. This Lie-Lorentz derivative appears naturally in the commutator of two supersymmetry transformations generated by Killing spinors and vanishes for Vielbeins. It can be identified as the generator of the action of isometries on supergravity fields and its use for the calculation of supersymmetry algebras is revised and extended.Comment: Latex2e, 9 pages, AMS font

Weak-Field Gravity of Revolving Circular Cosmic Strings

A weak-field solution of Einstein's equations is constructed. It is generated by a circular cosmic string revolving in its plane about the centre of the circle. (The revolution is introduced to prevent the string from collapsing.) This solution exhibits a conical singularity, and the corresponding deficit angle is the same as for a straight string of the same linear energy density, irrespective of the angular velocity of the string.Comment: 13 pages, LaTe

Maxwell's theory on a post-Riemannian spacetime and the equivalence principle

The form of Maxwell's theory is well known in the framework of general relativity, a fact that is related to the applicability of the principle of equivalence to electromagnetic phenomena. We pose the question whether this form changes if torsion and/or nonmetricity fields are allowed for in spacetime. Starting from the conservation laws of electric charge and magnetic flux, we recognize that the Maxwell equations themselves remain the same, but the constitutive law must depend on the metric and, additionally, may depend on quantities related to torsion and/or nonmetricity. We illustrate our results by putting an electric charge on top of a spherically symmetric exact solution of the metric-affine gauge theory of gravity (comprising torsion and nonmetricity). All this is compared to the recent results of Vandyck.Comment: 9 pages, REVTeX, no figures; minor changes, version to be published in Class. Quantum Gra

Coherent methods in the X-ray sciences

X-ray sources are developing rapidly and their coherent output is growing extremely rapidly. The increased coherent flux from modern X-ray sources is being matched with an associated rapid development in experimental methods. This article reviews the literature describing the ideas that utilise the increased brilliance from modern X-ray sources. It explores how ideas in coherent X-ray science are leading to developments in other areas, and vice versa. The article describes measurements of coherence properties and uses this discussion as a base from which to describe partially-coherent diffraction and X-ray phase contrast imaging, with its applications in materials science, engineering and medicine. Coherent diffraction imaging methods are reviewed along with associated experiments in materials science. Proposals for experiments to be performed with the new X-ray free-electron-lasers are briefly discussed. The literature on X-ray photon correlation spectroscopy is described and the features it has in common with other coherent X-ray methods are identified. Many of the ideas used in the coherent X-ray literature have their origins in the optical and electron communities and these connections are explored. A review of the areas in which ideas from coherent X-ray methods are contributing to methods for the neutron, electron and optical communities is presented.Comment: A review articel accepted by Advances in Physics. 158 pages, 29 figures, 3 table

The Sequence of An 8.8-kb Segment On the Left Arm of Chromosome-ii From Saccharomyces-cerevisiae Reveals 4 New Open Reading Frames Including Homologs of Animal Dna-polymerase Alpha-primases and Bacterial Gtp Cyclohydrolase-ii

The DNA sequence of two contiguous 7648 bp and 1194 bp BamHI fragments from the cosmid alpha 1201 located about 60 kb from the centromere on the left arm of chromosome II from Saccharomyces cerevisiae has been determined. Sequence analysis reveals four new open reading frames longer than 300 bp: YBL0415 (309 bp), YBL0416(4539 bp), YBL0417 (1035 bp) and YBL0414 (2115 bp), which extends into the neighbouring 5.2 kb BamHI fragment. The YBL0414 shows homologies to the mouse 68 kDa and Drosophila melanogaster 76 kDa subunits of the DNA polymerase alpha-primase complex. The YBL0417 is homologous to bacterial GTP cyclohydrolase II (EC 3.5.4.25). The sequence has been deposited in the EMBC data library under Accession Number X74738

Climate change, air pollution and human health

This article takes stock of recent literature on health impacts of climate change and air pollution, and the corresponding health benefits of policy action aiming to reduce greenhouse gas and air pollutant emissions. We focus particularly on the publications in the Focus Collection on ‘Climate Change, Air Pollution and Human Health’, which illustrate advances in three key research areas. First, the impacts of global warming and air pollution are unevenly distributed, as they disproportionately affect vulnerable socio-economic groups including older adults, pregnant women, children, and people with lower earnings or education levels. Second, recent research improves our understanding and quantification of impacts identified in earlier work, and explores novel impact pathways such as the associations between allergies and climate change, and between air pollution and diabetes mellitus, Alzheimer’s disease and Parkinson’s disease. Third, significant synergies in tackling climate change and air pollution can strengthen the case for ambitious policy action. These synergies are heterogeneous across sectors and regions, point to low-hanging fruit among policy options (e.g. phasing out coal), and provide a strong basis for broader sustainable development, improving health and gender equality. Finally, we point out suggestions for future research. Research advances can guide policies to mitigate future climate change, air pollution and the associated health impacts, while informing adaptation strategies that aim to protect the health of the most vulnerable in society