541 research outputs found
Letter from M.A. McLaughlin, Boston, Massachusetts, to Anne Whitney, Shelburne, New Hampshire, 1912 June 29
https://repository.wellesley.edu/whitney_correspondence/2758/thumbnail.jp
Dim Isolated Neutron Stars, Cooling and Energy Dissipation
The cooling and reheating histories of dim isolated neutron stars(DINs) are
discussed. Energy dissipation due to dipole spindown with ordinary and magnetar
fields, and due to torques from a fallback disk are considered as alternative
sources of reheating which would set the temperature of the neutron star after
the initial cooling era. Cooling or thermal ages are related to the numbers and
formation rates of the DINs and therefore to their relations with other
isolated neutron star populations. Interaction with a fallback disk, higher
multipole fields and activity of the neutron star are briefly discussed.Comment: To appear in Astrophysics and Space Science, in the proceedings of
the conference "Isolated Neutron Stars: from the Interior to the Surface",
London, April 2006; eds. D. Page, R. Turolla and S. Zane. Revised version:
with minor change and typos correcte
Persistent and Transient Blank Field Sources
Blank field sources (BFS) are good candidates for hosting dim isolated
neutron stars (DINS). The results of a search of BFS in the ROSAT HRI images
are revised. We then focus on transient BFS, arguing that they belong to a
rather large population. The perspectives of future research on DINS are then
discussed.Comment: 3 pages, 0 figures. Paper presented at the Conference "Isolated
Neutron Stars: from the interior to the surface", London, April 2006.
Astrophysics and Space Science, in pres
Valence-electron transfer and a metal-insulator transition in a strongly correlated perovskite oxide
We present transport and thermal data for the quadruple-perovskites
MCu3(Ti1-xRux)4O12 where 0 < x < 1. A metal-insulator transition (MIT) occurs
for Ru concentrations x~0.75. At the same time, the Cu2+ antiferromagnetic
state is destroyed and it's magnetic entropy suppressed by Ru on a 1:1 basis.
This implies that each Ru transfers an electron to a Cu ion and thus the MIT
correlates with filling the Cu 3d shell. The Cu spin entropy in this strongly
correlated electron material provides a unique probe among MIT systems.Comment: 15 pages, 4 figures, 1 tabl
Evaluation of the performance of a lateral flow device for quantitative detection of anti-SARS-CoV-2 IgG
Introduction: The AbC-19™ lateral flow immunoassay (LFIA) performance was evaluated on plasma samples from a SARS-CoV-2 vaccination cohort, WHO international standards for anti-SARS-CoV-2 IgG (human), individuals ≥2 weeks from infection of RT-PCR confirmed SARS-CoV-2 genetic variants, as well as microorganism serology. Methods: Pre-vaccination to three weeks post-booster samples were collected from a cohort of 111 patients (including clinically extremely vulnerable patients) from Northern Ireland. All patients received Oxford-AstraZeneca COVID-19 vaccination for the first and second dose, and Pfizer-BioNTech for the third (first booster). WHO international standards, 15 samples from 2 variants of concern (Delta and Omicron) and cross-reactivity with plasma samples from other microorganism infections were also assessed on AbC-19™. Results: All 80 (100%) participants sampled post-booster had high positive IgG responses, compared to 38/95 (40%) participants at 6 months post-first vaccination. WHO standard results correlated with information from corresponding biological data sheets, and antibodies to all genetic variants were detected by LFIA. No cross-reactivity was found with exception of one (of five) Dengue virus samples. Conclusion: These findings suggest BNT162b2 booster vaccination enhanced humoral immunity to SARS-CoV-2 from pre-booster levels, and that this antibody response was detectable by the LFIA. In combination with cross-reactivity, standards and genetic variant results would suggest LFIA may be a cost-effective measure to assess SARS-CoV-2 antibody status
Young star clusters in M31
In our study of M31's globular cluster system with MMT/Hectospec, we have
obtained high-quality spectra of 85 clusters with ages less than 1 Gyr. With
the exception of Hubble V, the young cluster in NGC 205, we find that these
young clusters have kinematics and spatial distribution consistent with
membership in M31's young disk. Preliminary estimates of the cluster masses and
structural parameters, using spectroscopically derived ages and HST imaging,
confirms earlier suggestions that M31 has clusters similar to the LMC's young
populous clusters.Comment: 4 pages, 1 figure, contributed talk at "Galaxies in the Local Volume"
conference in Sydney, July 200
Listening to #2A: Applying a Qualitative Method to Twitter Dialogue
In this article, we present a project that explored the application of an established qualitative methodology to a novel source of data: microblog postings on the social media platform Twitter, also known as tweets. In particular, we adapted Consensual Qualitative Research (CQR; Hill, Thompson, & Williams, 1997) for use in this analysis. The coinciding aim of the project was to study the cultural impasses that seemed to characterize U.S. society surrounding the 2016 presidential election. Publicly available tweets bearing the hashtag #2A were selected for examination; this hashtag indicated the user’s intention to direct the posting to the attention of Twitter users in the context of the Second Amendment, which refers to citizens’ right to bear arms. The article describes the process by which CQR was modified for this use, profiles the exploratory findings, and present suggestions for subsequent similar research undertakings
Chandra Smells a RRAT: X-ray Detection of a Rotating Radio Transient
"Rotating RAdio Transients" (RRATs) are a newly discovered astronomical
phenomenon, characterised by occasional brief radio bursts, with average
intervals between bursts ranging from minutes to hours. The burst spacings
allow identification of periodicities, which fall in the range 0.4 to 7
seconds. The RRATs thus seem to be rotating neutron stars, albeit with
properties very different from the rest of the population. We here present the
serendipitous detection with the Chandra X-ray Observatory of a bright
point-like X-ray source coincident with one of the RRATs. We discuss the
temporal and spectral properties of this X-ray emission, consider counterparts
in other wavebands, and interpret these results in the context of possible
explanations for the RRAT population.Comment: 5 pages, 2 b/w figures, 1 color figure. To appear in the proceedings
of "Isolated Neutron Stars", Astrophysics & Space Science, in pres
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