Stalled labor: homebirth parents, gender, and ritual in the US

2011 Spring.Includes bibliographical references.Pregnancy and birth are not purely biological, but fraught in every human culture with a great deal of meaning. Home birth, though unusual in the US, offers an opportunity to examine the cultural beliefs of those that choose it. Through a series of semi-structured ethnographic interviews with homebirth mothers, partners, and midwives, I find that these parents hope to transform the culture of birth to empower women, include men more fully, and give babies a gentler welcome into the world. This thesis draws on feminist and symbolic anthropological theories to examine midwife-attended pregnancy and birth at home as a rite of passage in which the parents both enact and are socialized into their new roles as parents. The mothers learn that a healthy birth is a commodity to be earned or purchased, that society has few obligations to the individual, and that the body gives birth. Fathers receive the related, though not identical, messages that the family is (or should be) self-sufficient, that they are responsible, and that birth care is a business. Both mothers and fathers move in and out of conventionally-gendered activities and roles as they negotiate pregnancy and birth. In the context of ritual, this has the possibility of subverting or reinforcing gender norms. The parents must grapple with this as they raise their new children, and find themselves torn between the desire to foster individuality and coping with the consequences of their children's non-conformity. They resolve this through denying their own role in socialization and attributing their children's gendered activities to individual choice. Though they challenge many ideas about gender as they attempt to change the culture of birth, I find that this labor is stalled: much work remains to be done to empower women and make men more central in birth

Using Stable Isotopes to Understand Seasonal Interactions in a Long-Distance Migratory Songbird

Recent advances in the analysis of intrinsic markers, particularly stable isotopes, have allowed great insight into interactions between different stages of the annual cycle of migratory birds. Hydrogen isotope ratios, because of strong latitudinal trends in their distribution, have been widely used to address long-distance movements of migratory birds. Likewise, carbon isotope ratios have been useful in examinations of habitat quality because of their responsiveness to changes in plant community composition. However, basic assumptions underlying the use of certain isotopes have yet to be adequately examined. Additionally, much of the research regarding seasonal interactions in migratory songbirds comes from study of a single species, and it is unclear whether these findings are applicable to a wider range of migrant songbirds. In this study, I collected tissue samples from black-throated blue warblers (Dendroica caerulescens) at a breeding site in New Hampshire to address two important questions regarding stable isotopes and the investigation of seasonal interactions. First, using feather samples from both adult and juvenile birds, I investigated the influence of age, molt timing, and reproductive effort in determining the stable hydrogen isotope ratios that are incorporated into tissue samples. Secondly, I took claw samples from adult birds to examine the importance of winter habitat quality, as inferred through carbon isotope ratios, in determining subsequent reproductive success. I found that hydrogen isotope ratios in feather samples were significantly influenced by both age and molt timing, though not by reproductive effort. The mechanism underlying age-related isotopic variation is unclear, but may be widespread among passerines. In addition, this study is the first to note a significant seasonal trend in feathers grown throughout a breeding season, although the mechanism for this pattern is also unclear. Taken together, these findings have important implications for the use of hydrogen isotope ratios for purposes of geographic assignment. Further research is needed to determine the prevalence and magnitude of age-related and seasonal trends in hydrogen isotope ratios. I recommend that future studies note the age class of birds when sampling for hydrogen isotopes, and researchers should attempt to collect feathers grown early in the molt cycle. Analysis of carbon isotope ratios from claw samples indicated that winter habitat quality did not directly influence subsequent reproductive success. However, winter habitat quality may have an indirect influence on reproductive output. Females from higher quality wintering sites were in significantly better body condition on the breeding grounds, and settled on more insect-rich breeding territories. Both body condition on the breeding grounds and breeding territory quality have previously been shown to influence subsequent reproductive success, in this and other songbird species. These results indicate that winter habitat quality may be important in determining future reproductive success for black-throated blue warblers, and interactions between events during the wintering and breeding periods may need to be incorporated into future population models for this species

Quantitative fat and R2* mapping in vivo to measure lipid-rich necrotic core and intraplaque hemorrhage in carotid atherosclerosis

Purpose: The aim of this work was to quantify the extent of lipid-rich necrotic core (LRNC) and intraplaque hemorrhage (IPH) in atherosclerotic plaques. Methods: Patients scheduled for carotid endarterectomy underwent four-point Dixon and T1-weighted magnetic resonance imaging (MRI) at 3 Tesla. Fat and R2* maps were generated from the Dixon sequence at the acquired spatial resolution of 0.60 × 0.60 × 0.70 mm voxel size. MRI and three-dimensional (3D) histology volumes of plaques were registered. The registration matrix was applied to segmentations denoting LRNC and IPH in 3D histology to split plaque volumes in regions with and without LRNC and IPH. Results: Five patients were included. Regarding volumes of LRNC identified by 3D histology, the average fat fraction by MRI was significantly higher inside LRNC than outside: 12.64 ± 0.2737% versus 9.294 ± 0.1762% (mean ± standard error of the mean [SEM]; P < 0.001). The same was true for IPH identified by 3D histology, R2* inside versus outside IPH was: 71.81 ± 1.276 s−1 versus 56.94 ± 0.9095 s−1 (mean ± SEM; P < 0.001). There was a strong correlation between the cumulative fat and the volume of LRNC from 3D histology (R2 = 0.92) as well as between cumulative R2* and IPH (R2 = 0.94). Conclusion: Quantitative mapping of fat and R2* from Dixon MRI reliably quantifies the extent of LRNC and IPH

Adverse cardiovascular magnetic resonance phenotypes are associated with greater likelihood of incident coronavirus disease 2019: findings from the UK Biobank.

BACKGROUND: Coronavirus disease 2019 (COVID-19) disproportionately affects older people. Observational studies suggest indolent cardiovascular involvement after recovery from acute COVID-19. However, these findings may reflect pre-existing cardiac phenotypes. AIMS: We tested the association of baseline cardiovascular magnetic resonance (CMR) phenotypes with incident COVID-19. METHODS: We studied UK Biobank participants with CMR imaging and COVID-19 testing. We considered left and right ventricular (LV, RV) volumes, ejection fractions, and stroke volumes, LV mass, LV strain, native T1, aortic distensibility, and arterial stiffness index. COVID-19 test results were obtained from Public Health England. Co-morbidities were ascertained from self-report and hospital episode statistics (HES). Critical care admission and death were from HES and death register records. We investigated the association of each cardiovascular measure with COVID-19 test result in multivariable logistic regression models adjusting for age, sex, ethnicity, deprivation, body mass index, smoking, diabetes, hypertension, high cholesterol, and prior myocardial infarction. RESULTS: We studied 310 participants (n = 70 positive). Median age was 63.8 [57.5, 72.1] years; 51.0% (n = 158) were male. 78.7% (n = 244) were tested in hospital, 3.5% (n = 11) required critical care admission, and 6.1% (n = 19) died. In fully adjusted models, smaller LV/RV end-diastolic volumes, smaller LV stroke volume, and poorer global longitudinal strain were associated with significantly higher odds of COVID-19 positivity. DISCUSSION: We demonstrate association of pre-existing adverse CMR phenotypes with greater odds of COVID-19 positivity independent of classical cardiovascular risk factors. CONCLUSIONS: Observational reports of cardiovascular involvement after COVID-19 may, at least partly, reflect pre-existing cardiac status rather than COVID-19 induced alterations

Quality Control-Driven Image Segmentation Towards Reliable Automatic Image Analysis in Large-Scale Cardiovascular Magnetic Resonance Aortic Cine Imaging

“The final authenticated version is available online at https://doi.org/10.1007/978-3-030-32245-8_83.”© 2019, Springer Nature Switzerland AG. Recent progress in fully-automated image segmentation has enabled efficient extraction of clinical parameters in large-scale clinical imaging studies, reducing laborious manual processing. However, the current state-of-the-art automatic image segmentation may still fail, especially when it comes to atypical cases. Visual inspection of segmentation quality is often required, thus diminishing the improvements in efficiency. This drives an increasing need to enhance the overall data processing pipeline with robust automatic quality scoring, especially for clinical applications. We present a novel quality control-driven (QCD) framework to provide reliable segmentation using a set of different neural networks. In contrast to the prior segmentation and quality scoring methods, the proposed framework automatically selects the optimal segmentation on-the-fly from the multiple candidate segmentations available, directly utilizing the inherent Dice similarity coefficient (DSC) predictions. We trained and evaluated the framework on a large-scale cardiovascular magnetic resonance aortic cine image sequences from the UK Biobank Study. The framework achieved segmentation accuracy of mean DSC at 0.966, mean prediction error of DSC within 0.015, and mean error in estimating lumen area ≤17.6 mm2 for both ascending aorta and proximal descending aorta. This novel QCD framework successfully integrates the automatic image segmentation along with detection of critical errors on a per-case basis, paving the way towards reliable fully-automatic extraction of clinical parameters for large-scale imaging studies

T2-Weighted intracranial vessel wall imaging at 7 Tesla using a DANTE-prepared variable flip angle turbo spin echo readout (DANTE-SPACE).

PURPOSE: To optimize intracranial vessel wall imaging (VWI) at 7T for sharp wall depiction and high boundary contrast. METHODS: A variable flip angle turbo spin echo scheme (SPACE) was optimized for VWI. SPACE provides black-blood contrast, but has less crushing effect on cerebrospinal fluid (CSF). However, a delay alternating with nutation for tailored excitation (DANTE) preparation suppresses the signal from slowly moving spins of a few mm per second. Therefore, we optimized a DANTE-preparation module for 7T. Signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and signal ratio for vessel wall, CSF, and lumen were calculated for SPACE and DANTE-SPACE in 11 volunteers at the middle cerebral artery (MCA). An exemplar MCA stenosis patient was scanned with DANTE-SPACE. RESULTS: The 7T-optimized SPACE sequence improved the vessel wall point-spread function by 17%. The CNR between the wall and CSF was doubled (12.2 versus 5.6) for the DANTE-SPACE scans compared with the unprepared SPACE. This increase was significant in the right hemisphere (P = 0.016), but not in the left (P = 0.090). The CNR between wall and lumen was halved, but remained at a high value (24.9 versus 56.5). CONCLUSION: The optimized SPACE sequence improves VWI at 7T. Additional DANTE preparation increases the contrast between the wall and CSF. Increased outer boundary contrast comes at the cost of reduced inner boundary contrast

Poor Bone Quality is Associated With Greater Arterial Stiffness: Insights From the UK Biobank

Osteoporosis and ischemic heart disease (IHD) represent important public health problems. Existing research suggests an association between the two conditions beyond that attributable to shared risk factors, with a potentially causal relationship. In this study, we tested the association of bone speed of sound (SOS) from quantitative heel ultrasound with (i) measures of arterial compliance from cardiovascular magnetic resonance (aortic distensibility [AD]); (ii) finger photoplethysmography (arterial stiffness index [ASI]); and (iii) incident myocardial infarction and IHD mortality in the UK Biobank cohort. We considered the potential mediating effect of a range of blood biomarkers and cardiometabolic morbidities and evaluated differential relationships by sex, menopause status, smoking, diabetes, and obesity. Furthermore, we considered whether associations with arterial compliance explained association of SOS with ischemic cardiovascular outcomes. Higher SOS was associated with lower arterial compliance by both ASI and AD for both men and women. The relationship was most consistent with ASI, likely relating to larger sample size available for this variable (n = 159,542 versus n = 18,229). There was no clear evidence of differential relationship by menopause, smoking, diabetes, or body mass index (BMI). Blood biomarkers appeared important in mediating the association for both men and women, but with different directions of effect and did not fully explain the observed effects. In fully adjusted models, higher SOS was associated with significantly lower IHD mortality in men, but less robustly in women. The association of SOS with ASI did not explain this observation. In conclusion, our findings support a positive association between bone and vascular health with consistent patterns of association in men and women. The underlying mechanisms are complex and appear to vary by sex

The UK Biobank imaging enhancement of 100,000 participants: rationale, data collection, management and future directions

UK Biobank is a population-based cohort of half a million participants aged 40–69 years recruited between 2006 and 2010. In 2014, UK Biobank started the world’s largest multi-modal imaging study, with the aim of re-inviting 100,000 participants to undergo brain, cardiac and abdominal magnetic resonance imaging, dual-energy X-ray absorptiometry and carotid ultrasound. The combination of large-scale multi-modal imaging with extensive phenotypic and genetic data offers an unprecedented resource for scientists to conduct health-related research. This article provides an in-depth overview of the imaging enhancement, including the data collected, how it is managed and processed, and future direction