On the spectroastrometric separation of binary point-source fluxes

Spectroastrometry is a technique which has the potential to resolve flux distributions on scales of milliarcseconds. In this study, we examine the application of spectroastrometry to binary point sources which are spatially unresolved due to the observational point spread function convolution. The technique uses measurements with sub-pixel accuracy of the position centroid of high signal-to-noise long-slit spectrum observations. With the objects in the binary contributing fractionally more or less at different wavelengths (particularly across spectral lines), the variation of the position centroid with wavelength provides some information on the spatial distribution of the flux. We examine the width of the flux distribution in the spatial direction, and present its relation to the ratio of the fluxes of the two components of the binary. Measurement of three observables (total flux, position centroid and flux distribution width) at each wavelength allows a unique separation of the total flux into its component parts even though the angular separation of the binary is smaller than the observations' point-spread function. This is because we have three relevant observables for three unknowns (the two fluxes, and the angular separation of the binary), which therefore generates a closed problem. This is a wholly different technique than conventional deconvolution methods, which produce information on angular sizes of the sampling scale. Spectroastrometry can produce information on smaller scales than conventional deconvolution, and is successful in separating fluxes in a binary object with a separation of less than one pixel. We present an analysis of the errors involved in making binary object spectroastrometric measurements and the separation method, and highlight necessary observing methodology.Comment: 11 pages, 8 figures, accepted for publication in Astronomy and Astrophysic

Catching the “Tail/Tale” of Teaching Qualitative Inquiry to Novice Researchers

This article responds to the call for deeper examination of qualitative inquiry teaching practices by presenting representative examples from the pedagogies of three teacher-educators who have taught Qualitative Research Methods courses for the past 15 years. We focus in particular on the pedagogical complexities of teaching data analysis, which is a topic that remains under-theorized and under-represented in contemporary scholarship on qualitative methodologies. Using a critical friends framework, we analyze and synthesize our pedagogical responses to key dilemmas we have encountered in our respective contexts, all state universities, to introducing qualitative inquiry to novice researchers who often enter the analytic process with positivist notions of knowledge creation. They sometimes enter the analytic process with the belief if they can only “catch the tail” of this thing called qualitative research they will be able to “do it right.” Yet, as the metaphor implies, catching a fierce beast by the tail, thinking you can control its actions, can intrude on the inductive and holistic character of the qualitative inquiry process

Creative Qualitative Inquiry And Digital Methodological Imaginations

This panel will address the concept of Creative Qualitative Inquiry practices used by three university faculty members who teach qualitative research methodology courses for doctoral students at different institutions. Innovative pedagogies will be explored with an emphasis on ways to nurture graduate students’ digital methodological imaginations as they are learning to analyze qualitative data. Panelists will discuss the implications of using technology including multimodal digital stories

Norovirus Polymerase Fidelity Contributes to Viral Transmission In Vivo.

Intrahost genetic diversity and replication error rates are intricately linked to RNA virus pathogenesis, with alterations in viral polymerase fidelity typically leading to attenuation during infections in vivo. We have previously shown that norovirus intrahost genetic diversity also influences viral pathogenesis using the murine norovirus model, as increasing viral mutation frequency using a mutagenic nucleoside resulted in clearance of a persistent infection in mice. Given the role of replication fidelity and genetic diversity in pathogenesis, we have now investigated whether polymerase fidelity can also impact virus transmission between susceptible hosts. We have identified a high-fidelity norovirus RNA-dependent RNA polymerase mutant (I391L) which displays delayed replication kinetics in vivo but not in cell culture. The I391L polymerase mutant also exhibited lower transmission rates between susceptible hosts than the wild-type virus and, most notably, another replication defective mutant that has wild-type levels of polymerase fidelity. These results provide the first experimental evidence that norovirus polymerase fidelity contributes to virus transmission between hosts and that maintaining diversity is important for the establishment of infection. This work supports the hypothesis that the reduced polymerase fidelity of the pandemic GII.4 human norovirus isolates may contribute to their global dominance. IMPORTANCE Virus replication fidelity and hence the intrahost genetic diversity of viral populations are known to be intricately linked to viral pathogenesis and tropism as well as to immune and antiviral escape during infection. In this study, we investigated whether changes in replication fidelity can impact the ability of a virus to transmit between susceptible hosts by the use of a mouse model for norovirus. We show that a variant encoding a high-fidelity polymerase is transmitted less efficiently between mice than the wild-type strain. This constitutes the first experimental demonstration that the polymerase fidelity of viruses can impact transmission of infection in their natural hosts. These results provide further insight into potential reasons for the global emergence of pandemic human noroviruses that display alterations in the replication fidelity of their polymerases compared to nonpandemic strains

How safe is your curry? Food allergy awareness of restaurant staff

Background: Incidents of severe and fatal anaphylaxis to accidentally ingested food allergens are increasing. Individuals are more likely to encounter difficulties when eating away from home. In restaurants, front-of-house and kitchen staff may be called upon to provide information about ingredients or ensure certain food allergens are excluded from dishes. Following a series of reactions related to the accidental ingestion of peanuts in curries we assessed food allergy awareness and allergen avoidance practices amongst the staff of Asian-Indian restaurants. Methods: A questionnaire survey was administered by telephone to one member of staff in each restaurant. Results: Fifty percent (40/80) of restaurants participated. Responders included managers, owners, waiters and chefs. Most (90%) had received food hygiene training, but only 15% food allergy training. 25% could name three common food allergens. 3 in 4 listed nuts, but less than 1in 5 mentioned peanuts. Common misunderstandings included 60% of staff believing an individual experiencing an allergic reaction should drink water to dilute the allergen. A less prevalent, but perhaps more concerning, was the misunderstanding that cooking food would prevent it causing an allergic reaction (25%). Despite poor knowledge, all respondents were comfortable and 65% were “very comfortable” with providing a “safe” meal for a customer with a food allergy. 60% expressed interest in future food allergy training. Conclusions: Despite high confidence in their own understanding of allergy, many staff lacked the knowledge to provide “safe” meals for food allergic customers. Traditionally tree nuts are a common ingredient in Asian-Indian dishes cuisine and there was widespread, but not universal, awareness of tree nuts as a common allergen. Peanuts were less commonly recognised as a common allergen, an observation of extreme concern as peanuts are being substituted for tree nuts as they are cheaper and avoid having to inflate meal prices. Our data highlights the need for greater training of restaurant staff. In parallel, food allergic customers need to exercise vigilance when making meal choices and develop skills to order a safe meal. The management of allergy is multifaceted, and this study indicates the importance of health professionals working beyond the clinical setting to collaborate with colleagues in the hospitality industry, public health and environmental health in coordinated endeavours to improve patient safety

Land Grant Application- Bailey, Israel (Minot)

Land grant application submitted to the Maine Land Office on behalf of Israel Bailey for service in the Revolutionary War, by their widow Lucy.https://digitalmaine.com/revolutionary_war_me_land_office/1045/thumbnail.jp

The murine norovirus core subgenomic RNA promoter consists of a stable stem-loop that can direct accurate initiation of RNA synthesis.

UNLABELLED: All members of the Caliciviridae family of viruses produce a subgenomic RNA during infection. The subgenomic RNA typically encodes only the major and minor capsid proteins, but in murine norovirus (MNV), the subgenomic RNA also encodes the VF1 protein, which functions to suppress host innate immune responses. To date, the mechanism of norovirus subgenomic RNA synthesis has not been characterized. We have previously described the presence of an evolutionarily conserved RNA stem-loop structure on the negative-sense RNA, the complementary sequence of which codes for the viral RNA-dependent RNA polymerase (NS7). The conserved stem-loop is positioned 6 nucleotides 3' of the start site of the subgenomic RNA in all caliciviruses. We demonstrate that the conserved stem-loop is essential for MNV viability. Mutant MNV RNAs with substitutions in the stem-loop replicated poorly until they accumulated mutations that revert to restore the stem-loop sequence and/or structure. The stem-loop sequence functions in a noncoding context, as it was possible to restore the replication of an MNV mutant by introducing an additional copy of the stem-loop between the NS7- and VP1-coding regions. Finally, in vitro biochemical data suggest that the stem-loop sequence is sufficient for the initiation of viral RNA synthesis by the recombinant MNV RNA-dependent RNA polymerase, confirming that the stem-loop forms the core of the norovirus subgenomic promoter. IMPORTANCE: Noroviruses are a significant cause of viral gastroenteritis, and it is important to understand the mechanism of norovirus RNA synthesis. Here we describe the identification of an RNA stem-loop structure that functions as the core of the norovirus subgenomic RNA promoter in cells and in vitro. This work provides new insights into the molecular mechanisms of norovirus RNA synthesis and the sequences that determine the recognition of viral RNA by the RNA-dependent RNA polymerase.This is the author's accepted manuscript. The final version is available from the American Society for Microbiology at http://jvi.asm.org/content/89/2/1218.lon

Land Grant Application- Bailey, John (Turner)

Land grant application submitted to the Maine Land Office on behalf of John Bailey for service in the Revolutionary War, by their widow Lucy B..https://digitalmaine.com/revolutionary_war_me_land_office/1047/thumbnail.jp

The Axially Symmetric Ejecta of Supernova 1987A

Extensive early observations proved that the ejecta of supernova 1987A (SN 1987A) are aspherical. Fifteen years after the supernova explosion, the Hubble Space Telescope has resolved the rapidly expanding ejecta. The late-time images and spectroscopy provide a geometrical picture that is consistent with early observations and suggests a highly structured, axially symmetric geometry. We present here a new synthesis of the old and new data. We show that the Bochum event, presumably a clump of $^{56}$Ni, and the late-time image, the locus of excitation by $^{44}$Ti, are most naturally accounted for by sharing a common position angle of about 14\degree, the same as the mystery spot and early speckle data on the ejecta, and that they are both oriented along the axis of the inner circumstellar ring at 45\degree to the plane of the sky. We also demonstrate that the polarization represents a prolate geometry with the same position angle and axis as the early speckle data and the late-time image and hence that the geometry has been fixed in time and throughout the ejecta. The Bochum event and the Doppler kinematics of the [Ca II]/[O II] emission in spatially resolved HST spectra of the ejecta can be consistently integrated into this geometry. The radioactive clump is deduced to fall approximately along the axis of the inner circumstellar ring and therefore to be redshifted in the North whereas the [Ca II]/[O II] 7300 \AA emission is redshifted in the South. We present a jet-induced model for the explosion and argue that such a model can account for many of the observed asymmetries. In the jet models, the oxygen and calcium are not expected to be distributed along the jet, but primarily in an expanding torus that shares the plane and northern blue shift of the inner circumstellar ring.Comment: To Appear in Ap