92 research outputs found
Overcoming Impostor Syndrome
ALA Core\u27s AvramCamp is designed to be a safe and inclusive day-long workshop for people of marginalized genders, including women, non-binary folks, and trans men, to come together and discuss challenges these groups commonly face while working in the library technology field. Each AvramCamp begins with a workshop to talk about Impostor Syndrome: what it is, how to recognize it, and strategies to overcome those feelings of being a fake or a fraud. Participants are encouraged to engage with the facilitators, creating a lively and honest discussion around an often private and sensitive topic
The Effects of Home-Based Literacy Activities on the Communication of Students with Severe Speech and Motor Impairments
This study examined the effects of using sensory, augmentative, and alternative communication (AAC), and supportive communication strategies on the rate and type of communication used by three students with severe speech and motor impairments (SSMI). Using a multiple baseline across behaviour design with sensory and AAC intervention phases, students were paired with a family member during shared reading activities using familiar and unfamiliar storybooks in their homes. All reading activities were video-recorded for analysis. Examination of recorded readings revealed that students demonstrated increases in their overall rates of communication. Further, these students successfully integrated communication devices into the reading process. The results suggest that students with severe disabilities can benefit from these forms of literacy strategies to increase their participation in reading tasks. Implications for research and practice are discussed
Placenta Previa in the Second Trimester: Sonographic and Clinical Factors Associated with Its Resolution
To identify characteristics that predict resolution of placenta previa and to develop a clinical model for likelihood of resolution
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HLA Alleles Associated with Delayed Progression to AIDS Contribute Strongly to the Initial CD8+ T Cell Response against HIV-1
Background: Very little is known about the immunodominance patterns of HIV-1-specific T cell responses during primary HIV-1 infection and the reasons for human lymphocyte antigen (HLA) modulation of disease progression. Methods and Findings: In a cohort of 104 individuals with primary HIV-1 infection, we demonstrate that a subset of CD8+ T cell epitopes within HIV-1 are consistently targeted early after infection, while other epitopes subsequently targeted through the same HLA class I alleles are rarely recognized. Certain HLA alleles consistently contributed more than others to the total virus-specific CD8+ T cell response during primary infection, and also reduced the absolute magnitude of responses restricted by other alleles if coexpressed in the same individual, consistent with immunodomination. Furthermore, individual HLA class I alleles that have been associated with slower HIV-1 disease progression contributed strongly to the total HIV-1-specific CD8+ T cell response during primary infection. Conclusions: These data demonstrate consistent immunodominance patterns of HIV-1-specific CD8+ T cell responses during primary infection and provide a mechanistic explanation for the protective effect of specific HLA class I alleles on HIV-1 disease progression
An X-Ray-Selected Sample of Candidate Black Holes in Dwarf Galaxies
We present a sample of hard X-ray-selected candidate black holes (BHs) in 19 dwarf galaxies. BH candidates are identified by cross-matching a parent sample of ~44,000 local dwarf galaxies (M* = 3 × 10 9 M☉, z < 0.055) with the Chandra Source Catalog and subsequently analyzing the original X-ray data products for matched sources. Of the 19 dwarf galaxies in our sample, eight have X-ray detections reported here for the first time. We find a total of 43 point-like hard X-ray sources with individual luminosities L2-10 keV ~ 10 37 - 10 40 erg s-1. Hard X-ray luminosities in this range can be attained by stellar-mass X-ray binaries (XRBs) and by massive BHs accreting at low Eddington ratio. We place an upper limit of 53% (10/19) on the fraction of galaxies in our sample hosting a detectable hard X-ray source consistent with the optical nucleus, although the galaxy center is poorly defined in many of our objects. We also find that 42% (8/19) of the galaxies in our sample exhibit statistically significant enhanced hard X-ray emission relative to the expected galaxy-wide contribution from low-mass and high-mass XRBs, based on the [data] star formation rate relation defined by more massive and luminous systems. For the majority of these X-ray-enhanced dwarf galaxies, the excess emission is consistent with (but not necessarily due to) a nuclear X-ray source. Follow-up observations are necessary to distinguish between stellar-mass XRBs and active galactic nuclei powered by more massive BHs. In any case, our results support the notion that X-ray-emitting BHs in low-mass dwarf galaxies may have had an appreciable impact on reionization in the early universe
HLA Alleles Associated with Delayed Progression to AIDS Contribute Strongly to the Initial CD8(+) T Cell Response against HIV-1
BACKGROUND: Very little is known about the immunodominance patterns of HIV-1-specific T cell responses during primary HIV-1 infection and the reasons for human lymphocyte antigen (HLA) modulation of disease progression. METHODS AND FINDINGS: In a cohort of 104 individuals with primary HIV-1 infection, we demonstrate that a subset of CD8(+) T cell epitopes within HIV-1 are consistently targeted early after infection, while other epitopes subsequently targeted through the same HLA class I alleles are rarely recognized. Certain HLA alleles consistently contributed more than others to the total virus-specific CD8(+) T cell response during primary infection, and also reduced the absolute magnitude of responses restricted by other alleles if coexpressed in the same individual, consistent with immunodomination. Furthermore, individual HLA class I alleles that have been associated with slower HIV-1 disease progression contributed strongly to the total HIV-1-specific CD8(+) T cell response during primary infection. CONCLUSIONS: These data demonstrate consistent immunodominance patterns of HIV-1-specific CD8(+) T cell responses during primary infection and provide a mechanistic explanation for the protective effect of specific HLA class I alleles on HIV-1 disease progression
The X-ray properties of million solar mass black holes
We present new Chandra X-ray observations of seven low-mass black holes (~1e6
Msun) accreting at low Eddington ratios between -2.0<log L/Ledd<-1.5. We
compare the X-ray properties of these seven low-mass active galactic nuclei
(AGN) to a total of 73 other low-mass AGN in the literature with published
Chandra observations (with Eddington ratios extending from -2.0<log
L/Ledd<-0.1). We do not find any statistical differences between low- and
high-Eddington ratio low-mass AGN in the distributions of their X-ray to
ultraviolet luminosity ratios (aox), or in their X-ray spectral shapes.
Furthermore, the aox distribution of low-L/Ledd AGN displays an X-ray weak tail
that is also observed within high-L/Ledd objects. Our results indicate that
between -2<log L/Ledd<-0.1, there is no systematic change in the structure of
the accretion flow for active galaxies hosting 1e6 Msun black holes. We examine
the accuracy of current bolometric luminosity estimates for our low-L/Ledd
objects with new Chandra observations, and it is plausible that their Eddington
ratios could be underestimated by up to an order of magnitude. If so, then in
analogy with weak emission line quasars, we suggest that accretion from a
geometrically thick, radiatively inefficient `slim disk' could explain their
diverse properties in aox. Alternatively, if current Eddington ratios are in
fact correct (or overestimated), then the X-ray weak tail would imply that
there is diversity in disk/corona couplings among individual low-mass objects.
Finally, we conclude by noting that the aox distribution for low-mass black
holes may have favorable consequences for the epoch of cosmic reionization
being driven by AGN.Comment: 14 pages, 6 figures, 6 tables. Accepted for publication in Ap
Measurement of associated Z plus charm production in proton-proton collisions at root s=8TeV
A study of the associated production of a Z boson and a charm quark jet (Z + c), and a comparison to production with a b quark jet (Z + b), in pp collisions at a centre-of-mass energy of 8 TeV are presented. The analysis uses a data sample corresponding to an integrated luminosity of 19.7 fb(-1), collected with the CMS detector at the CERN LHC. The Z boson candidates are identified through their decays into pairs of electrons or muons. Jets originating from heavy flavour quarks are identified using semileptonic decays of c or b flavoured hadrons and hadronic decays of charm hadrons. The measurements are performed in the kinematic region with two leptons with pT(l) > 20 GeV, vertical bar eta(l)vertical bar 25 GeV and vertical bar eta(jet)vertical bar Z + c + X) B(Z -> l(+)l(-)) = 8.8 +/- 0.5 (stat)+/- 0.6 (syst) pb. The ratio of the Z+c and Z+b production cross sections is measured to be sigma(pp -> Z+c+X)/sigma (pp -> Z+b+X) = 2.0 +/- 0.2 (stat)+/- 0.2 (syst). The Z+c production cross section and the cross section ratio are also measured as a function of the transverse momentum of theZ boson and of the heavy flavour jet. The measurements are compared with theoretical predictions.Peer reviewe
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