ANTIBODY RESPONSES TO ANTIGENIC DETERMINANTS OF INFLUENZA VIRUS HEMAGGLUTININ : II. Original Antigenic Sin: A Bone Marrow-Derived Lymphocyte Memory Phenomenon Modulated by Thymus-Derived Lymphocytes

Mice immunized sequentially with two related influenza virus hemagglutinins (HA) produced a secondary antibody response with two different specificities. Some antibodies were specific for determinants common to both HA's. Paradoxically, some antibodies were directed to determinants existing only in the HA first encountered. Primed spleen cells treated with anti-θ serum and complement were transferred from animals immunized with the first HA to either normal, irradiated, or thymus-deprived recipients. These memory cells were boosted in the recipients with either the homologous or the heterologous cross-reacting HA. B-memory lymphocytes were shown to be directly triggered by both HA's and to be able to secrete, independently of T lymphocytes, antibodies to both kinds of determinants. However, T cells were shown to modulate this secondary response by either enhancing or suppressing antibody secretion by B-memory cells, depending on experimental conditions. These results are discussed in terms of antigen recognition by B cells and of kinetics of development of immunological memory

ANTIBODY RESPONSES TO ANTIGENIC DETERMINANTS OF INFLUENZA VIRUS HEMAGGLUTININ : I. Thymus Dependence of Antibody Formation and Thymus Independence of Immunological Memory

Using immunodiffusion methods it has been shown that purified hemagglutinin (HA) extracted from two related strains of influenza A viruses (A/PR8/34 and A/FM1/47) have two distinct antigenic determinants, or groups of determinants. One determinant is cross-reactive while the other is strain-specific. Antisera raised in normal mice against HA were shown to contain two populations of antibody molecules, each directed against one of the determinants. Immunization of thymus-deprived (TXBM) mice showed a strong thymus dependence of antibody formation to HA. However, the thymus dependence of antibody formation against the cross-reactive determinant could be overcome by repeated inoculations of HA in TXBM mice, indicating a different handling of two portions of the same molecule by the immunological system. Strong, secondary-type responses to the strain-specific determinant were observed in primed thymus-deprived mice after reconstitution with virgin thymus cells, showing that specific immunological memory was elicited by this determinant despite the absence of detectable antibody secretion. These findings are interpreted as examples of immunological recognition and memory mediated by B lymphocytes and discussed in terms of mechanisms of T and B lymphocyte co-operation. It is suggested that the helper effect of T lymphocytes is exerted at a late stage in the differentiation of specific populations of B cells into antibody-secreting cells

Diversity, differentiation, and linkage disequilibrium: prospects for association mapping in the malaria vector anopheles arabiensis

Association mapping is a widely applied method for elucidating the genetic basis of phenotypic traits. However, factors such as linkage disequilibrium and levels of genetic diversity influence the power and resolution of this approach. Moreover, the presence of population subdivision among samples can result in spurious associations if not accounted for. As such, it is useful to have a detailed understanding of these factors before conducting association mapping experiments. Here we conducted whole-genome sequencing on 24 specimens of the malaria mosquito vector, Anopheles arabiensis, to further understanding of patterns of genetic diversity, population subdivision and linkage disequilibrium in this species. We found high levels of genetic diversity within the An. arabiensis genome, with ~800,000 high-confidence, single- nucleotide polymorphisms detected. However, levels of nucleotide diversity varied significantly both within and between chromosomes. We observed lower diversity on the X chromosome, within some inversions, and near centromeres. Population structure was absent at the local scale (Kilombero Valley, Tanzania) but detected between distant populations (Cameroon vs. Tanzania) where differentiation was largely restricted to certain autosomal chromosomal inversions such as 2Rb. Overall, linkage disequilibrium within An. arabiensis decayed very rapidly (within 200 bp) across all chromosomes. However, elevated linkage disequilibrium was observed within some inversions, suggesting that recombination is reduced in those regions. The overall low levels of linkage disequilibrium suggests that association studies in this taxon will be very challenging for all but variants of large effect, and will require large sample sizes

Paper: Expert Viewers\u27 Preferences for Higher Frame Rate 3D Film

Recently the movie industry has been advocating the use of frame rates significantly higher than the traditional 24 frames per second. This higher frame rate theoretically improves the quality of motion portrayed in movies, and helps avoid motion blur, judder and other undesirable artifacts. Previously we reported that young adult audiences showed a clear preference for higher frame rates, particularly when contrasting 24 fps with 48 or 60 fps. We found little impact of shutter angle (frame exposure time) on viewers’ choices. In the current study we replicated this experiment with an audience composed of imaging professionals who work in the film and display industry who assess image quality as an aspect of their everyday occupation. These viewers were also on average older and thus could be expected to have attachments to the “film look” both through experience and training. We used stereoscopic 3D content, filmed and projected at multiple frame rates (24, 48 and 60 fps), with shutter angles ranging from 90◦ to 358◦, to evaluate viewer preferences. In paired-comparison experiments we assessed preferences along a set of five attributes (realism, motion smoothness, blur/clarity, quality of depth and overall preference). As with the young adults in the earlier study, the expert viewers showed a clear preference for higher frame rates, particularly when contrasting 24 fps with 48 or 60 fps. We found little impact of shutter angle on viewers’ choices, with the exception of one clip at 48 fps where there was a preference for larger shutter angle. However, this preference was found for the most dynamic “warrior” clip in the experts but in the slower moving “picnic” clip for the naïve viewers. These data confirm the advantages afforded by high-frame rate capture and presentation in a cinema context in both naïve audiences and experienced film professionals.https://source.sheridancollege.ca/centres_sirt_works/1002/thumbnail.jp

Evidence that Viewers Prefer Higher Frame Rate Film

High frame rate (HFR) movie-making refers to the capture and projection of movies at frame rates several times higher than the traditional 24 frames per second. This higher frame rate theoretically improves the quality of motion portrayed in movies, and helps avoid motion blur, judder and other undesirable artefacts. However, there is considerable debate in the cinema industry regarding the acceptance of HFR content given anecdotal reports of hyper-realistic imagery that reveals too much set and costume detail. Despite the potential theoretical advantages, there has been little empirical investigation of the impact of high-frame rate techniques on the viewer experience. In this study we use stereoscopic 3D content, filmed and projected at multiple frame rates (24, 48 and 60 fps), with shutter angles ranging from 90 degrees to 358 degrees, to evaluate viewer preferences. In a paired-comparison paradigm we assessed preferences along a set of five attributes (realism, motion smoothness, blur/clarity, quality of depth and overall preference). The resulting data show a clear preference for higher frame rates, particularly when contrasting 24 fps with 48 or 60 fps. We found little impact of shutter angle on viewers’ choices, with the exception of one measure (motion smoothness) for one clip type. These data are the first empirical evidence of the advantages afforded by high frame rate capture and presentation in a cinema context.https://source.sheridancollege.ca/centres_sirt_works/1000/thumbnail.jp

Differential Burden of Musculoskeletal Pain in Blacks and Whites at the Time of Total Joint Replacement Surgery

Introduction: The existence of racial disparities in total knee (TKR) and hip (THR) replacement outcomes is well established. The role of musculoskeletal co-morbidities among black and white TKR patients at the time of surgery were investigated in a prospective cohort enrolled in the FORCE-TJR consortium of 131 surgeons in 22 US states. Materials & methods: Descriptive analyses were performed on 3,306 TKR and 2,439 THR patients. Data included sociodemographic factors (age, sex, race), BMI, comorbid conditions using the modified Charlson comorbidity scores, burden of musculoskeletal disease using the Knee/Hip injury and Osteoarthritis Outcome Score (KOOS/HOOS) in both knees and hips, emotional health based on the Short Form 36 (SF-36) Mental Component Score (MCS) and physical function based on the Physical Component Score (SF-36 PCS). Factors associated with pre-operative surgical joint pain and function were examined using multivariate stepwise linear regression models. Results: Compared to Whites, Blacks (143 hips and 201 knees) reported worse surgical joint pain (mean pain: 39.3 vs. 49.2 (hip); 43.4 vs. 53.2 (knee)), poorer surgical joint function (mean function: 38.9 vs. 45.7 (hip); 45.9 vs. 53.4 (knee)), poorer global function (mean PCS: 30.0 vs. 31.6 (hip); 31.3 vs. 33.1 (knee)), and more non-operative joints pain. (All p\u3c0.03). In adjusted multivariable models, differences at the time of surgery in surgical joint symptoms and global function were explained by differences in musculoskeletal pain in the hips, knees, and low back. Conclusion: Greater burden of musculoskeletal pain explains differences in pre-operative pain and function between Blacks and Whites and likely impacts rehabilitation and subsequent TJR outcomes

Differential burden of musculoskeletal pain in African Americans and whites patients at the time of total joint replacement surgery

Objective: African Americans patients have greater operative joint pain and functional limitation at the time of total joint replacement (TJR) compared to white patients. We examined the factors associated with this apparent disparity. Methods: A consecutive sample of 5745 patients with advanced knee and hip osteoarthritis [who elected to undergo TJR in 2011-201] reported, preoperatively, medical comorbidities, operative and non-operative hip/ knee pain using Hip and Knee Disability and Osteoarthritis Outcome Scores (HOOS/KOOS), function using Short Form 36 Physical Component Score (PCS). Total burden of musculoskeletal pain was quantified as moderate/severe pain in non-operative hip and knee joints and lumbar back pain using Oswestry Disability Index (ODI). Associations among race, medical co-morbidites (modified Charlson), total musculoskeletal pain burden, operative joint pain, and functional limitations were examined using multivariable regression models. Results:Compared to Whites, African Americans (143 hips and 201 knees) reported worse surgical joint pain (mean pain: 39.3 vs. 49.2 [hip]; 43.4 vs. 53.2 [knee]), poorer surgical joint function (mean function: 38.9 vs. 45.7 [hip]; 45.9 vs. 53.4 [knee]), poorer global function (mean PCS: 30.0 vs. 31.6 [hip]; 31.3 vs. 33.1 [knee]), and more non-operative joints pain (p Conclusions: Greater burden of musculoskeletal pain explains differences in pre-operative pain and function between African American and white patients and likely impacts rehabilitation and subsequent TJR outcomes

Perceived partner responsiveness, daily negative affect reactivity, and all-cause mortality:A 20-year longitudinal study

Objective This study tested longitudinal associations between absolute levels of perceived partner responsiveness (PPR; how much people perceive that their romantic partners understand, care for, and appreciate them), daily negative affect reactivity and positive affect reactivity, and all-cause mortality in a sample of 1,208 adults for three waves of data collection spanning 20 years. We also tested whether longitudinal changes in PPR predicted mortality via affect reactivity. Methods Data were taken from the National Survey of Midlife Development in the United States. PPR was assessed at waves 1 and 2, affect reactivity to stressors was assessed by daily diary reports at wave 2, and mortality status was obtained at wave 3. Results Mediation analyses revealed absolute levels of PPR at wave 1 predicted wave 3 mortality via wave 2 affective reactivity in the predicted direction, but this did not remain robust when statistically accounting for covariates (e.g., marital risk, neuroticism), beta = .004, 95% confidence interval = -.03 to .04. However, wave 1-2 PPR change predicted negative affect (but not positive affect) reactivity to daily stressors at wave 2, which then predicted mortality risk a decade later (wave 3); these results held when adjusting for relevant demographic, health, and psychosocial covariates, beta = -.04, 95% confidence interval = -.09 to -.002. Conclusions These findings are among the first to provide direct evidence of psychological mechanisms underlying the links between intimate relationships and mortality and have implications for research aiming to develop interventions that increase or maintain responsiveness in relationships over time

The connection between the escape of ionizing radiation and galaxy properties at z~3 in the Keck Lyman Continuum Spectroscopic Survey

The connection between the escape fraction of ionizing radiation ($f_{esc}$) and the properties of galaxies, such as stellar mass (M*), age, star-formation rate (SFR), and dust content, are key inputs for reionization models, but many of these relationships remain untested at high redshift. We present an analysis of a sample of 96 z~3 galaxies from the Keck Lyman Continuum Spectroscopic Survey (KLCS). These galaxies have both sensitive Keck/LRIS spectroscopic measurements of the Lyman continuum (LyC) region, and multi-band photometry that places constraints on stellar population parameters. We construct composite spectra from subsamples binned as a function of galaxy property and quantify the ionizing-photon escape for each composite. We find a significant anti-correlation between $f_{esc}$ and M*, consistent with predictions from cosmological zoom-in simulations. We also find significant anti-correlation between $f_{esc}$ and E(B-V), encoding the underlying physics of LyC escape in our sample. We also find no significant correlation between $f_{esc}$ and either stellar age or specific SFR (=SFR/M*), challenging interpretations that synchronize recent star formation and favorable conditions for ionizing escape. The galaxy properties now shown to correlate with $f_{esc}$ in the KLCS are Ly$\alpha$ equivalent width, UV Luminosity, M*, SFR, and E(B-V), but not age or sSFR. To date, this is the most comprehensive analysis of galaxy properties and LyC escape at high redshift, and will be used to guide future models and observations of the reionization epoch.Comment: 13 pages, 5 figures, submitted to MNRA