2,965 research outputs found
Non-lethal PCR genotyping of single Drosophila
In Drosophila, genetic techniques relying on stochastic chromosomal rearrangements involve the generation and screening of a large number of fly stocks to isolate a few lines of interest. Here, we describe a PCR-based method allowing non-lethal molecular characterization of single flies. Using this procedure, individual candidate recombinant animals can be genotyped and selected one generation earlier than with extant methodology and, importantly, before stocks are established. This advance should significantly facilitate several of the most fundamental and routine techniques in Drosophila genetics
The Claims Culture: A Taxonomy of Industry Attitudes
This paper presents an analysis of a familiar aspect of construction industry culture that we have dubbed 'the claims culture'. This is a culture of contract administration that lays a strong emphasis on the planning and management of claims. The principal elements of the analysis are two sets of distinctions. The first comprises economic and occupational orders, referring to two kinds of control that are exercised over the construction process; predicated respectively on economic ownership and occupational competence. The second refers to contrasting attitudes towards relationships and problem solving within these orders: respectively 'distributive' and 'integrative'. The concepts of economic and occupational order entail further sub-categories. The various attitudes associated with these categories and sub-categories are described. They are assessed as to their consequences for change initiatives in the industry
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Pain Control by Co-adaptive Learning in a Brain-Machine Interface.
Innovation in the field of brain-machine interfacing offers a new approach to managing human pain. In principle, it should be possible to use brain activity to directly control a therapeutic intervention in an interactive, closed-loop manner. But this raises the question as to whether the brain activity changes as a function of this interaction. Here, we used real-time decoded functional MRI responses from the insula cortex as input into a closed-loop control system aimed at reducing pain and looked for co-adaptive neural and behavioral changes. As subjects engaged in active cognitive strategies orientated toward the control system, such as trying to enhance their brain activity, pain encoding in the insula was paradoxically degraded. From a mechanistic perspective, we found that cognitive engagement was accompanied by activation of the endogenous pain modulation system, manifested by the attentional modulation of pain ratings and enhanced pain responses in pregenual anterior cingulate cortex and periaqueductal gray. Further behavioral evidence of endogenous modulation was confirmed in a second experiment using an EEG-based closed-loop system. Overall, the results show that implementing brain-machine control systems for pain induces a parallel set of co-adaptive changes in the brain, and this can interfere with the brain signals and behavior under control. More generally, this illustrates a fundamental challenge of brain decoding applications-that the brain inherently adapts to being decoded, especially as a result of cognitive processes related to learning and cooperation. Understanding the nature of these co-adaptive processes informs strategies to mitigate or exploit them
Searching for R-Parity Violation at Run-II of the Tevatron
We present an outlook for possible discovery of supersymmetry with broken
R-parity at Run II of the Tevatron. We first present a review of the literature
and an update of the experimental bounds. In turn we then discuss the following
processes: 1. Resonant slepton production followed by R-parity violating decay,
(a) via and (b) via . 2. How to distinguish resonant slepton
production from or production. 3. Resonant slepton production
followed by the decay to neutralino LSP, which decays via . 4. Resonant
stop production followed by the decay to a chargino, which cascades to the
neutralino LSP. 5. Gluino pair production followed by the cascade decay to
charm squarks which decay directly via . 6. Squark pair production
followed by the cascade decay to the neutralino LSP which decays via
. 7. MSSM pair production followed by the cascade decay to the LSP
which decays (a) via , (b) via , and (c) via ,
respectively. 8. Top quark and top squark decays in spontaneous R-parity
violation.Comment: 39 pages, 51 figures, LaTex, reqires aipproc2.sty and axodraw.sty. To
be published in the Physics at Run II Workshop: Supersymmetry/Higgs. Text has
been edited by H. Dreiner. Author list on front page has been correcte
Galaxy protocluster candidates around z ~ 2.4 radio galaxies
We study the environments of 6 radio galaxies at 2.2 < z < 2.6 using
wide-field near-infrared images. We use colour cuts to identify galaxies in
this redshift range, and find that three of the radio galaxies are surrounded
by significant surface overdensities of such galaxies. The excess galaxies that
comprise these overdensities are strongly clustered, suggesting they are
physically associated. The colour distribution of the galaxies responsible for
the overdensity are consistent with those of galaxies that lie within a narrow
redshift range at z ~ 2.4. Thus the excess galaxies are consistent with being
companions of the radio galaxies. The overdensities have estimated masses in
excess of 10^14 solar masses, and are dense enough to collapse into virizalised
structures by the present day: these structures may evolve into groups or
clusters of galaxies. A flux-limited sample of protocluster galaxies with K <
20.6 mag is derived by statistically subtracting the fore- and background
galaxies. The colour distribution of the protocluster galaxies is bimodal,
consisting of a dominant blue sequence, comprising 77 +/- 10% of the galaxies,
and a poorly populated red sequence. The blue protocluster galaxies have
similar colours to local star-forming irregular galaxies (U -V ~ 0.6),
suggesting most protocluster galaxies are still forming stars at the observed
epoch. The blue colours and lack of a dominant protocluster red sequence
implies that these cluster galaxies form the bulk of their stars at z < 3.Comment: Accepted for publication in MNRA
Nonlinearization and waves in bounded media: old wine in a new bottle
We consider problems such as a standing wave in a closed straight tube, a self-sustained oscillation, damped resonance, evolution of resonance and resonance between concentric spheres. These nonlinear problems, and other similar ones, have been solved by a variety of techniques when it is seen that linear theory fails. The unifying approach given here is to initially set up the appropriate linear difference equation, where the difference is the linear travel time. When the linear travel time is replaced by a corrected nonlinear travel time, the nonlinear difference equation yields the required solution
Fast Radio Burst Tomography of the Unseen Universe
The discovery of Fast Radio Bursts (FRBs) at cosmological distances has
opened a powerful window on otherwise unseen matter in the Universe. In the
2020s, observations of FRBs will assess the baryon contents and
physical conditions in the hot/diffuse circumgalactic, intracluster, and
intergalactic medium, and test extant compact-object dark matter models.Comment: Science white paper submitted to the Astro2020 Decadal Survey. 15
pages, 3 color figure
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