766 research outputs found
Resurgent Insurgents:Quantitative Research Into Jihadists Who Get Suspended but Return on Twitter
Jihadists are very active on Twitter but their accounts frequently get suspended. A substantial debate over the effectiveness of suspension has arisen; an important factor is that Jihadists quickly create new accounts, resurging back like a game of whack-a-mole. This causes biases for terrorism and intelligence analysts. Whilst widely acknowledged, little research addresses the problem. In this study we identify resurging Jihadist accounts with novel methods, and provide detailed analysis going beyond previous case-studies. We show that suspension is less disruptive to terrorists than previously thought, whilst the bias and disruption caused to terrorism research has been underestimated
How does school size affect tail beat frequency in turbulent water?
The energy savings experienced by fish swimming in a school have so far been investigated in an near-idealised experimental context including a relatively laminar water flow. The effects of explicitly turbulent flows and different group sizes are yet to be considered. Our repeated-measures study is a first step in addressing both of these issues: whether schooling is more energetically economical for fish when swimming in a quantified non-laminar flow and how this might be moderated by group size. We measured tail beat frequency (tbf) in sea bass swimming in a group of 3 or 6, or singly. Video data enabled us to approximately track the movements of the fish during the experiments and in turn ascertain the water flow rates and turbulence levels experienced for each target individual. Although the fish exhibited reductions in tbf during group swimming, which may indicate some energy savings, these savings appear to be attenuated, presumably due to the water turbulence and the movement of the fish relative to each other. Surprisingly, tbf was unrelated to flow rate when the fish were swimming singly or in a group of three, and decreased with increasing flow rates when swimming in a group of six. However, the fish increased tbf in greater turbulence at all group sizes. Our study demonstrates that under the challenging and complex conditions of turbulent flow and short-term changes in school structure, group size can moderate the influences of water flow on a fish's swimming kinematics, and in turn perhaps their energy costs.
Summary statement:
The energy savings that sea bass experience from schooling are affected by flow speed or turbulence, moderated by group size
High surface area coatings for hydrogen evolution cathodes prepared by magnetron sputtering
A novel magnetron sputtering technique is described for the deposition of durable, high surface area metal and alloy deposits (thickness up to several microns) onto nickel and steel substrates. The materials deposited include platinum, nickel, nickel alloys and steels. The structure of the deposits is characterised and it is demonstrated that some high surface area coatings are efficient and effective electrocatalysts for hydrogen evolution in alkaline media and coated mesh electrodes have been tested in a modern water electrolyser configuration.UK Technology Strategy Boar
Primary care computing in England and Scotland: a comparison with Denmark
This paper compares the status of primary care computing in England and Scotland with that of Denmark. The rate of utilisation by Danish GPs is among the highest in the world and the MedCom national health network handles over 90% of the country's primary sector clinical communications. A high proportion of English and Scottish GPs also use computers in their clinical practices, and like their Danish colleagues, they benefit from more accurate and streamlined medications management, particularly in terms of repeat prescriptions. The historical forces and factors which influenced the development of primary care computing are identified and discussed
Single nucleotide polymorphisms (SNPs) distinguish Indian-origin and Chinese-origin rhesus macaques (Macaca mulatta)
BACKGROUND: Rhesus macaques serve a critical role in the study of human biomedical research. While both Indian and Chinese rhesus macaques are commonly used, genetic differences between these two subspecies affect aspects of their behavior and physiology, including response to simian immunodeficiency virus (SIV) infection. Single nucleotide polymorphisms (SNPs) can play an important role in both establishing ancestry and in identifying genes involved in complex diseases. We sequenced the 3' end of rhesus macaque genes in an effort to identify gene-based SNPs that could distinguish between Indian and Chinese rhesus macaques and aid in association analysis. RESULTS: We surveyed the 3' end of 94 genes in 20 rhesus macaque animals. The study included 10 animals each of Indian and Chinese ancestry. We identified a total of 661 SNPs, 457 of which appeared exclusively in one or the other population. Seventy-nine additional animals were genotyped at 44 of the population-exclusive SNPs. Of those, 38 SNPs were confirmed as being population-specific. CONCLUSION: This study demonstrates that the 3' end of genes is rich in sequence polymorphisms and is suitable for the efficient discovery of gene-linked SNPs. In addition, the results show that the genomic sequences of Indian and Chinese rhesus macaque are remarkably divergent, and include numerous population-specific SNPs. These ancestral SNPs could be used for the rapid scanning of rhesus macaques, both to establish animal ancestry and to identify gene alleles that may contribute to the phenotypic differences observed in these populations
Single Nucleotide Polymorphisms (SNPs) Distinguish Indian-Origin and Chinese-Origin Rhesus Macaques (Macaca Mulatta)
BACKGROUND: Rhesus macaques serve a critical role in the study of human biomedical research. While both Indian and Chinese rhesus macaques are commonly used, genetic differences between these two subspecies affect aspects of their behavior and physiology, including response to simian immunodeficiency virus (SIV) infection. Single nucleotide polymorphisms (SNPs) can play an important role in both establishing ancestry and in identifying genes involved in complex diseases. We sequenced the 3\u27 end of rhesus macaque genes in an effort to identify gene-based SNPs that could distinguish between Indian and Chinese rhesus macaques and aid in association analysis.
RESULTS: We surveyed the 3\u27 end of 94 genes in 20 rhesus macaque animals. The study included 10 animals each of Indian and Chinese ancestry. We identified a total of 661 SNPs, 457 of which appeared exclusively in one or the other population. Seventy-nine additional animals were genotyped at 44 of the population-exclusive SNPs. Of those, 38 SNPs were confirmed as being population-specific.
CONCLUSION: This study demonstrates that the 3\u27 end of genes is rich in sequence polymorphisms and is suitable for the efficient discovery of gene-linked SNPs. In addition, the results show that the genomic sequences of Indian and Chinese rhesus macaque are remarkably divergent, and include numerous population-specific SNPs. These ancestral SNPs could be used for the rapid scanning of rhesus macaques, both to establish animal ancestry and to identify gene alleles that may contribute to the phenotypic differences observed in these populations
The Angular Power Spectra of Photometric SDSS LRGs
We construct new galaxy angular power spectra based on the extended, updated
and final SDSS II Luminous Red Galaxy (LRG) photometric redshift survey: MegaZ
DR7. Encapsulating 7746 deg^{2} we utilise 723,556 photometrically determined
LRGs between 0.45 < z < 0.65 in a 3.3 (Gpc h^{-1})^3 spherical harmonic
analysis of the galaxy distribution. By combining four photometric redshift
bins we find preliminary parameter constraints of f_{b} = \Omega_{b}/\Omega_{m}
= 0.173 +/- 0.046 and \Omega_{m} = 0.260 +/- 0.035 assuming H_{0} = 75 km
s^{-1} Mpc^{-1}, n_{s}=1 and \Omega_{k} = 0. These limits are consistent with
the CMB and the previous data release (DR4). The C_{\ell} are sensitive to
redshift space distortions and therefore we also recast our constraints into a
measurement of \beta ~ \Omega_{m}^{0.55}/b in different redshift shells. The
robustness of these power spectra with respect to a number of potential
systematics such as extinction, photometric redshift and ANNz training set
extrapolation are examined. The latter includes a cosmological comparison of
available photometric redshift estimation codes where we find excellent
agreement between template and empirical estimation methods. MegaZ DR7
represents a methodological prototype to next generation surveys such as the
Dark Energy Survey (DES) and, furthermore, is a photometric precursor to the
spectroscopic BOSS survey. Our galaxy catalogue and all power spectra data can
be found at http://zuserver2.star.ucl.ac.uk/~sat/MegaZ/MegaZDR7.tar.gz.Comment: MNRAS Accepted: 20 pages - Galaxy catalogue and power spectra
included onlin
Investigating change across time in prevalence or association: the challenges of cross-study comparative research and possible solutions
Cross-study research initiatives to understand change across time are an increasingly prominent component of social and health sciences, yet they present considerable practical, analytical and conceptual challenges. First, we discuss the key challenges to comparative research as a basis for detecting societal change, as well as possible solutions. We focus on studies which investigate changes across time in outcome occurrence or the magnitude and/or direction of associations. We discuss the use and importance of such research, study inclusion, sources of bias and mitigation, and interpretation. Second, we propose a structured framework (a checklist) that is intended to provide guidance for future authors and reviewers. Third, we outline a new open-access teaching resource that offers detailed instruction and reusable analytical syntax to guide newcomers on techniques for conducting comparative analysis and data visualisation (in both R and Stata formats).</p
- …