Cytological analysis of MRE11 protein during early meiotic prophase I in Arabidopsis and tomato

Early recombination nodules (ENs) are multiprotein complexes that are thought to be involved in synapsis and recombination, but little is known about their components or how they may be involved in these events. In this study, we describe the cytological behavior of a possible EN component, MRE11, a protein that is important for the repair of the numerous, programmed deoxyribonucleic acid double-strand breaks (DSBs) that occur early in the meiotic prophase. By immunofluorescence, many MRE11 foci were associated with chromosomal axes during early prophase I in both wild-type Arabidopsis and tomato primary microsporocytes. Similar patterns of MRE11 foci were observed in two Arabidopsis mutants (Atspo11-1 and Atprd1) that are defective in DSB formation and synapsis. In tomato chromosomes, MRE11 foci were more common in distal euchromatin than in proximal heterochromatin, consistent with known EN patterns. However, electron microscopic immunogold localization demonstrated that only about 10% of ENs were labeled, and most MRE11 label was associated with synaptonemal complex components. Thus, in plants, MRE11 foci are not dependent on DSB formation, and most MRE11 foci do not correspond to ENs. More generally, our results show that the simple presence of large numbers of fluorescent foci associated with synapsing chromosomes is insufficient evidence to equate these foci with ENs

The Pioneer Anomaly in the Light of New Data

The radio-metric tracking data received from the Pioneer 10 and 11 spacecraft from the distances between 20-70 astronomical units from the Sun has consistently indicated the presence of a small, anomalous, blue-shifted Doppler frequency drift that limited the accuracy of the orbit reconstruction for these vehicles. This drift was interpreted as a sunward acceleration of a_P = (8.74+/-1.33)x10^{-10} m/s^2 for each particular spacecraft. This signal has become known as the Pioneer anomaly; the nature of this anomaly is still being investigated. Recently new Pioneer 10 and 11 radio-metric Doppler and flight telemetry data became available. The newly available Doppler data set is much larger when compared to the data used in previous investigations and is the primary source for new investigation of the anomaly. In addition, the flight telemetry files, original project documentation, and newly developed software tools are now used to reconstruct the engineering history of spacecraft. With the help of this information, a thermal model of the Pioneers was developed to study possible contribution of thermal recoil force acting on the spacecraft. The goal of the ongoing efforts is to evaluate the effect of on-board systems on the spacecrafts' trajectories and possibly identify the nature of this anomaly. Techniques developed for the investigation of the Pioneer anomaly are applicable to the New Horizons mission. Analysis shows that anisotropic thermal radiation from on-board sources will accelerate this spacecraft by ~41 x 10^{-10} m/s^2. We discuss the lessons learned from the study of the Pioneer anomaly for the New Horizons spacecraft.Comment: 19 pages, 5 figure

Non-destructive, dynamic detectors for Bose-Einstein condensates

We propose and analyze a series of non-destructive, dynamic detectors for Bose-Einstein condensates based on photo-detectors operating at the shot noise limit. These detectors are compatible with real time feedback to the condensate. The signal to noise ratio of different detection schemes are compared subject to the constraint of minimal heating due to photon absorption and spontaneous emission. This constraint leads to different optimal operating points for interference-based schemes. We find the somewhat counter-intuitive result that without the presence of a cavity, interferometry causes as much destruction as absorption for optically thin clouds. For optically thick clouds, cavity-free interferometry is superior to absorption, but it still cannot be made arbitrarily non-destructive . We propose a cavity-based measurement of atomic density which can in principle be made arbitrarily non-destructive for a given signal to noise ratio

Q-dependence of the inelastic neutron scattering cross section for molecular spin clusters with high molecular symmetry

For powder samples of polynuclear metal complexes the dependence of the inelastic neutron scattering intensity on the momentum transfer Q is known to be described by a combination of so called interference terms. They reflect the interplay between the geometrical structure of the compound and the spatial properties of the wave functions involved in the transition. In this work, it is shown that the Q-dependence is strongly interrelated with the molecular symmetry of molecular nanomagnets, and, if the molecular symmetry is high enough, is actually completely determined by it. A general formalism connecting spatial symmetry and interference terms is developed. The arguments are detailed for cyclic spin clusters, as experimentally realized by e.g. the octanuclear molecular wheel Cr8, and the star like tetranuclear cluster Fe4.Comment: 8 pages, 1 figures, REVTEX

SRAO CO Observation of 11 Supernova Remnants in l = 70 to 190 deg

We present the results of 12CO J = 1-0 line observations of eleven Galactic supernova remnants (SNRs) obtained using the Seoul Radio Astronomy Observatory (SRAO) 6-m radio telescope. The observation was made as a part of the SRAO CO survey of SNRs between l = 70 and 190 deg, which is intended to identify SNRs interacting with molecular clouds. The mapping areas for the individual SNRs are determined to cover their full extent in the radio continuum. We used halfbeam grid spacing (60") for 9 SNRs and full-beam grid spacing (120") for the rest. We detected CO emission towards most of the remnants. In six SNRs, molecular clouds showed a good spatial relation with their radio morphology, although no direct evidence for the interaction was detected. Two SNRs are particularly interesting: G85.4+0.7, where there is a filamentary molecular cloud along the radio shell, and 3C434.1, where a large molecular cloud appears to block the western half of the remnant. We briefly summarize the results obtained for individual SNRs.Comment: Accepted for publication in Astrophysics & Space Science. 12 pages, 12 figures, and 3 table

Reflecting back and forwards: The ebb and flow of peer-reviewed reflective practice research in sport

Researchers in sport have claimed that reflective practice is important for competent practice. Evidence supporting this claim is sparse, highly theoretical and located within a variety of domains. The aim of this study was to assimilate and analyse the last 12 years of reflective practice literature within the sport domain in order to identify new areas of inquiry, emerging trends with regard to findings or methodology, and to identify implications for future research and practice. A sample of 68 papers published between 2001 and 2012 was examined, and investigated for the research locations, data collection methods utilised, and the professions and communities involved. The paper concludes with some suggestions for future research

Study protocol: Australasian Registry of Severe Cutaneous Adverse Reactions (AUS-SCAR)

Introduction Severe cutaneous adverse reactions (SCAR) are a group of T cell-mediated hypersensitivities associated with significant morbidity, mortality and hospital costs. Clinical phenotypes include Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS) and acute generalised exanthematous pustulosis (AGEP). In this Australasian, multicentre, prospective registry, we plan to examine the clinical presentation, drug causality, genomic predictors, potential diagnostic approaches, treatments and long-term outcomes of SCAR in Australia and New Zealand. Methods and analysis Adult and adolescent patients with SCAR including SJS, TEN, DRESS, AGEP and another T cell-mediated hypersensitivity, generalised bullous fixed drug eruption, will be prospectively recruited. A waiver of consent has been granted for some sites to retrospectively include cases which result in early mortality. DNA will be collected for all prospective cases. Blood, blister fluid and skin biopsy sampling is optional and subject to patient consent and site capacity. To develop culprit drug identification and prevention, genomic testing will be performed to confirm human leukocyte antigen (HLA) type and ex vivo testing will be performed via interferon-γ release enzyme linked immunospot assay using collected peripheral blood mononuclear cells. The long-term outcomes of SCAR will be investigated with a 12-month quality of life survey and examination of prescribing and mortality data. Ethics and dissemination This study was reviewed and approved by the Austin Health Human Research Ethics Committee (HREC/50791/Austin-19). Results will be published in peer-reviewed journals and presented at relevant conferences

Caribou, Petroleum, and the Limits of Locality in the Canada–US Borderlands

his article discusses Karsten Heuer’s 2006 book Being Caribou in light of debates in ecocriticism and border studies about how to define the local in the context of environmental problems of vast range and uncertain temporality. It explores how Heuer’s book about following the Porcupine Caribou herd’s migration engages in multiple forms of boundary crossing—between countries, between hemispheric locations, and between species—and shows how insights from Indigenous storytelling complicate the book’s appeal to environmentalist readers by asserting a prior, transnational Indigenous presence in the transboundary landscapes of present-day Alaska and the Yukon

Plasma Wakefield Acceleration with a Modulated Proton Bunch

The plasma wakefield amplitudes which could be achieved via the modulation of a long proton bunch are investigated. We find that in the limit of long bunches compared to the plasma wavelength, the strength of the accelerating fields is directly proportional to the number of particles in the drive bunch and inversely proportional to the square of the transverse bunch size. The scaling laws were tested and verified in detailed simulations using parameters of existing proton accelerators, and large electric fields were achieved, reaching 1 GV/m for LHC bunches. Energy gains for test electrons beyond 6 TeV were found in this case.Comment: 9 pages, 7 figure