Scan rate converter for tape recording and playback of TV pictures

Magnetic tape recording and playback equipment converts television pictures, both black and white and color, from one scan rate to another. The equipment indexes color picture frames for retrieval electronically and can be used as a document storage and retrieval medium that is compatible with hard-copy printout machines

Finitely generated soluble groups and their subgroups

We prove that every finitely generated soluble group which is not virtually abelian has a subgroup of one of a small number of types.Comment: 16 page

Highly extinguished emission line outflows in the young radio source PKS 1345+12

(Abridged) We present new, intermediate resolution spectra (~4A) of the compact radio source PKS 1345+12. Our spectra clearly show extended line emission (~20kpc) consistent with the asymmetric halo of diffuse emission observed in optical and infra-red images. In the nucleus we observe complex emission line profiles requiring 3 Gaussian components (narrow, intermediate and broad). The broadest component (FWHM ~2000 km/s) is blue shifted by ~2000 km/s with respect to the galaxy halo and HI absorption. We interpret this as material in outflow. We find evidence for high reddening and measure E(B-V)>0.92 for the broadest component. From [S II]6716,6731 we estimate electron densities of n_e5300 cm^{-3} and n_{e}>4200 cm^{-3} for the regions emitting the narrow, intermediate and broad components respectively. We calculate a total mass of line emitting gas of M_{gas}<10^6 solar masses. Not all emission line profiles can be reproduced by the same model: [O I]6300,6363 and [S II] require separate, unique models. We argue that PKS 1345+12 is a young radio source whose nuclear regions are enshrouded in a dense cocoon of gas and dust. The radio jets are expanding, sweeping material out of the nuclear regions. Emission originates from three kinematically distinct regions though gradients (e.g. density, ionisation potential, acceleration) must exist across the regions responsible for the emission of the intermediate and broad components.Comment: Accepted for publication in MNRAS, 13 pages, 8 postscript figure

Chiral Fermi liquid approach to neutron matter

We present a microscopic calculation of the complete quasiparticle interaction, including central as well as noncentral components, in neutron matter from high-precision two- and three-body forces derived within the framework of chiral effective field theory. The contributions from two-nucleon forces are computed in many-body perturbation theory to first and second order (without any simplifying approximations). In addition we include the leading-order one-loop diagrams from the N2LO chiral three-nucleon force, which contribute to all Fermi liquid parameters except those associated with the center-of-mass tensor interaction. The relative-momentum dependence of the quasiparticle interaction is expanded in Legendre polynomials up to L=2. Second-order Pauli blocking and medium polarization effects act coherently in specific channels, namely for the Landau parameters f_1, h_0 and g_0, which results in a dramatic increase in the quasiparticle effective mass as well as a decrease in both the effective tensor force and the neutron matter spin susceptibility. For densities greater than about half nuclear matter saturation density \rho_0, the contributions to the Fermi liquid parameters from the leading-order chiral three-nucleon force scale in all cases approximately linearly with the nucleon density. The largest effect of the three-nucleon force is to generate a strongly repulsive effective interaction in the isotropic spin-independent channel. We show that the leading-order chiral three-nucleon force leads to an increase in the spin susceptibility of neutron matter, but we observe no evidence for a ferromagnetic spin instability in the vicinity of the saturation density \rho_0. This work sets the foundation for future studies of neutron matter response to weak and electromagnetic probes with applications to neutron star structure and evolution.Comment: 21 pages, 6 figures, 5 table

Accretion disk coronae

Recent observations of partial X-ray eclipses from 4U1822-37 have shown that the central X-ray source in this system is diffused by a large Compton-thick accretion disk corona (ADC). Another binary, 4U2129-47, also displays a partial eclipse and contains an ADC. The possible origin of an ADC is discussed and a simple hydrostatic evaporated ADC model is developed which, when applied to 4U1822-37, 4U2129+47 and Cyg X-3, can explain their temporal and spectral properties. The quasi-sinusoidal modulation of all three sources can be reconciled with the partial occultation of the ADC by a bulge at the edge of the accretion disk which is caused by the inflowing material. The height of this bulge is an order of magnitude larger than the hydrostatic disk height and is the result of turbulence in the outer region of the disk. The spectral properties of all three sources can be understood in terms of Compton scattering of the original source spectrum by the ADC. Spectral variations with epoch in Cyg X-3 are probably caused by changes in the optical depth of the corona. A consequence of our model is that any accreting neutron star X-ray source in a semi-detached binary system which is close to its Eddington limit most likely contains an optically thick ADC

The neurological symptoms of COVID-19: A systematic overview of systematic reviews, comparison with other neurological conditions and implications for healthcare services

Objective: In response to the rapid spread of COVID-19, this paper provides health professionals with better accessibility to available evidence, summarising findings from a systematic overview of systematic reviews of the neurological symptoms seen in patients with COVID-19. Implications of so-called ‘Long Covid’ on neurological services and primary care and similarities with other neurological disorders are discussed. Methods: Firstly, a systematic overview of current reviews of neurological symptoms of COVID-19 was conducted. Secondly the implications of these findings are discussed in relation to the potential effect on neurological services and the similarities in the experience of patients with COVID-19 and those with other neurological disorders. Forty-five systematic reviews were identified within seven databases, published between 11th April 2020 and 15th October 2020, following a search in June 2020, updated on 20th October 2020. Results: The results indicated that COVID-19 exhibits two types of neurological symptoms; life threatening symptoms such as Guillain Barre Syndrome and encephalitis, and less devastating symptoms such as fatigue and myalgia. Many of these so-called lesser symptoms appear to be emerging as longer-term for some sufferers and have been recently labelled Long Covid. When compared, these less devastating symptoms are very similar to other neurological conditions such as Chronic Fatigue Syndrome (CFS) and Functional Neurological Disorder (FND). Conclusions: Implications for neurological healthcare services in the UK may include longer waiting times and a need for more resources (including more qualified health professionals). There is also a possible change-effect on health professionals’ perceptions of other neurological conditions such as CFS and FND. Future research is recommended to explore changes in health professionals’ perceptions of neurological symptoms because of COVID-19

Mother, researcher, feminist, woman: reflections on maternal status as researcher identity

Purpose – The purpose of this paper is to discuss the ways in which a researcher's maternal status as “mother” or “non-mother/child-free” is implicated in the research process. Design/methodology/approach – This paper draws on the experiences as two feminist researchers who each independently researched experiences of motherhood: one as a “mother” and one as a “non-mother/child-free”. The paper draws on extracts from the original interview data and research diaries to reflect on how research topic, methodology and interview practice are shaped by a researcher's maternal status. Findings – The paper found that the own maternal identities shaped the research process in a number of ways: it directed the research topic and access to research participants; it drove the method of data collection and analysis and it shaped how the authors interacted with the participants in the interview setting, notably through the performance of maternal identity. The paper concludes by examining how pervasive discourses of “good motherhood” are both challenged and reproduced by a researcher's maternal status and question the implications of this for feminist research. Originality/value – While much has been written about researcher “positionality” and the impact of researcher identity on the research process, the ways in which a researcher's “maternal status” is implicated in the research process has been left largely unexamined. Yet, as this paper highlights, the interaction of the often-conflicting identities of “mother”, “researcher”, “feminist” and “woman” may shape the research process in subtle yet profound ways, raising important questions about the limits of what feminist social research about “motherhood” can achieve