Cloning and characterisation of the S.pombe rad15 gene, a homologue to the S.cerevisiae RAD3 and human ERCC2 genes

The RAD3 gene of Saccharomyces cerevisiae encodes an ATP-dependent 5' - 3' DNA helicase, which is involved in excision repair of ultraviolet radiation damage. By hybridisation of a Schizosaccharomyces pombe genomic library with a RAD3 gene probe we have isolated the S.pombe homologue of RAD3. We have also cloned the rad15 gene of S.pombe by complementation of radiation-sensitive phenotype of the rad15 mutant. Comparison of the restriction map and DNA sequence, shows that the S.pombe rad15 gene is identical to the gene homologous to S.cerevisiae RAD3, identified by hybridisation. The S.pombe rad15.P mutant is highly sensitive to UV radiation, but only slightly sensitive to ionising radiation, as expected for a mutant defective in excision repair. DNA sequence analysis of the rad15 gene indicates an open reading frame of 772 amino acids, and this is consistent with a transcript size of 2.6kb as detected by Northern analysis. The predicted rad15 protein has 65% identity to RAD3 and 55% identity to the human homologue ERCC2. This homology is particularly striking in the regions identified as being conserved in a group of DNA helicases. Gene deletion experiments indicate that, like the S.cerevisiae RAD3 gene, the S.pombe rad15 gene is essential for viability, suggesting that the protein product has a role in cell proliferation and not solely in DNA repair

Iris: an Extensible Application for Building and Analyzing Spectral Energy Distributions

Iris is an extensible application that provides astronomers with a user-friendly interface capable of ingesting broad-band data from many different sources in order to build, explore, and model spectral energy distributions (SEDs). Iris takes advantage of the standards defined by the International Virtual Observatory Alliance, but hides the technicalities of such standards by implementing different layers of abstraction on top of them. Such intermediate layers provide hooks that users and developers can exploit in order to extend the capabilities provided by Iris. For instance, custom Python models can be combined in arbitrary ways with the Iris built-in models or with other custom functions. As such, Iris offers a platform for the development and integration of SED data, services, and applications, either from the user's system or from the web. In this paper we describe the built-in features provided by Iris for building and analyzing SEDs. We also explore in some detail the Iris framework and software development kit, showing how astronomers and software developers can plug their code into an integrated SED analysis environment.Comment: 18 pages, 8 figures, accepted for publication in Astronomy & Computin

The challenge of embedding an ecosystems approach:patterns of knowledge utilisation in public policy appraisal

The ‘ecosystem services approach’ (ESA) to policy making has refocused attention on how knowledge is embedded in policy. Appraisal has long been identified as an important venue for embedding, but suffers from well-known difficulties. This paper examines the extent to which an ESA appears in UK policy appraisal documents, and how far implementing an ESA via appraisal may encounter the same difficulties. A clear understanding of this is vital for interrogating claims that improving knowledge necessarily leads to more sustainable ecosystem management. The paper reports on the content of seventy-five national-level policy appraisals undertaken in the United Kingdom between 2008 and 2012. Only some elements of an ESA appear, with even the environment ministry failing to systematically pick up the concept, which is indeed subject to many of the familiar barriers to embedding environmental knowledge in appraisals. Policy initiatives attempting to institutionalise ecosystem values need to be conversant with these barriers

First E region observations of mesoscale neutral wind interaction with auroral arcs

We report the first observations of E region neutral wind fields and their interaction with auroral arcs at mesoscale spatial resolution during geomagnetically quiet conditions at Mawson, Antarctica. This was achieved by using a scanning Doppler imager, which can observe thermospheric neutral line-of-sight winds and temperatures simultaneously over a wide field of view. In two cases, the background E region wind field was perpendicular to an auroral arc, which when it appeared caused the wind direction within ∼50 km of the arc to rotate parallel along the arc, reverting to the background flow direction when the arc disappeared. This was observed under both westward and eastward plasma convection. The wind rotations occurred within 7–16 min. In one case, as an auroral arc propagated from the horizon toward the local zenith, the background E region wind field became significantly weaker but remained unaffected where the arc had not passed through. We demonstrate through modeling that these effects cannot be explained by height changes in the emission layer. The most likely explanation seems to be the greatly enhanced ion drag associated with the increased plasma density and localized ionospheric electric field associated with auroral arcs. In all cases, the F region neutral wind appeared less affected by the auroral arc, although its presence is clear in the data

Radar detection of a localized 1.4 Hz pulsation in auroral plasma, simultaneous with pulsating optical emissions, during a substorm

Many pulsating phenomena are associated with the auroral substorm. It has been considered that some of these phenomena involve kilometer-scale Alfvén waves coupling the magnetosphere and ionosphere. Electric field oscillations at the altitude of the ionosphere are a signature of such wave activity that could distinguish it from other sources of auroral particle precipitation, which may be simply tracers of magnetospheric activity. Therefore, a ground based diagnostic of kilometer-scale oscillating electric fields would be a valuable tool in the study of pulsations and the auroral substorm. In this study we attempt to develop such a tool in the Poker Flat incoherent scatter radar (PFISR). The central result is a statistically significant detection of a 1.4 Hz electric field oscillation associated with a similar oscillating optical emission, during the recovery phase of a substorm. The optical emissions also contain a bright, lower frequency (0.2 Hz) pulsation that does not show up in the radar backscatter. The fact that higher frequency oscillations are detected by the radar, whereas the bright, lower frequency optical pulsation is not detected by the radar, serves to strengthen a theoretical argument that the radar is sensitive to oscillating electric fields, but not to oscillating particle precipitation. Although it is difficult to make conclusions as to the physical mechanism, we do not find evidence for a plane-wave-like Alfvén wave; the detected structure is evident in only two of five adjacent beams. We emphasize that this is a new application for ISR, and that corroborating results are needed

Electron Radiated Power in Cyclotron Radiation Emission Spectroscopy Experiments

The recently developed technique of Cyclotron Radiation Emission Spectroscopy (CRES) uses frequency information from the cyclotron motion of an electron in a magnetic bottle to infer its kinetic energy. Here we derive the expected radio frequency signal from an electron in a waveguide CRES apparatus from first principles. We demonstrate that the frequency-domain signal is rich in information about the electron's kinematic parameters, and extract a set of measurables that in a suitably designed system are sufficient for disentangling the electron's kinetic energy from the rest of its kinematic features. This lays the groundwork for high-resolution energy measurements in future CRES experiments, such as the Project 8 neutrino mass measurement.Comment: 15 pages, 10 figure

Results from the Project 8 phase-1 cyclotron radiation emission spectroscopy detector

The Project 8 collaboration seeks to measure the absolute neutrino mass scale by means of precision spectroscopy of the beta decay of tritium. Our technique, cyclotron radiation emission spectroscopy, measures the frequency of the radiation emitted by electrons produced by decays in an ambient magnetic field. Because the cyclotron frequency is inversely proportional to the electron's Lorentz factor, this is also a measurement of the electron's energy. In order to demonstrate the viability of this technique, we have assembled and successfully operated a prototype system, which uses a rectangular waveguide to collect the cyclotron radiation from internal conversion electrons emitted from a gaseous $^{83m}$Kr source. Here we present the main design aspects of the first phase prototype, which was operated during parts of 2014 and 2015. We will also discuss the procedures used to analyze these data, along with the features which have been observed and the performance achieved to date.Comment: 3 pages; 2 figures; Proceedings of Neutrino 2016, XXVII International Conference on Neutrino Physics and Astrophysics, 4-9 July 2016, London, U

Magnetic aspect sensitivity of high‐latitude E region irregularities measured by the RAX‐2 CubeSat

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106761/1/jgra50801.pd

Dead layer on silicon p-i-n diode charged-particle detectors

Semiconductor detectors in general have a dead layer at their surfaces that is either a result of natural or induced passivation, or is formed during the process of making a contact. Charged particles passing through this region produce ionization that is incompletely collected and recorded, which leads to departures from the ideal in both energy deposition and resolution. The silicon \textit{p-i-n} diode used in the KATRIN neutrino-mass experiment has such a dead layer. We have constructed a detailed Monte Carlo model for the passage of electrons from vacuum into a silicon detector, and compared the measured energy spectra to the predicted ones for a range of energies from 12 to 20 keV. The comparison provides experimental evidence that a substantial fraction of the ionization produced in the "dead" layer evidently escapes by diffusion, with 46% being collected in the depletion zone and the balance being neutralized at the contact or by bulk recombination. The most elementary model of a thinner dead layer from which no charge is collected is strongly disfavored.Comment: Manuscript submitted to NIM