Antarctic ice shelves are losing mass at drastically different rates, primarily due to differing rates of oceanic heat supply to their bases. However, a generalized theory for the inflow of ...relatively warm water into ice shelf cavities is lacking. This study proposes such a theory based on a geostrophically constrained inflow, combined with a threshold bathymetric elevation, the Highest Unconnected isoBath (HUB), that obstructs warm water access to ice shelf grounding lines. This theory captures ∼ 90% of the variance in melt rates across a suite of idealized process‐oriented ocean/ice shelf simulations with quasi‐randomized geometries. Applied to observations of ice shelf geometries and offshore hydrography, the theory captures ∼80% of the variance in measured ice shelf melt rates. These findings provide a generalized theoretical framework for melt resulting from buoyancy‐driven warm water access to geometrically complex Antarctic ice shelf cavities.
Plain Language Summary
The floating extensions of Antarctic glaciers (“ice shelves”) are losing ice at drastically different rates. A large component of this ice loss is due to melting from below by relatively warm ocean waters, which typically lie hundreds of meters below the surface. Previous studies have attempted to predict ice shelf melt rates using knowledge of the interface between the ice and the ocean. However, these relationships struggle to capture the variations in melt rates around Antarctica, in part because they do not account for obstruction of warm water access by variations in the shae of the seafloor. In this study we introduce a theory for the rate at which warm waters access Antarctica's ice shelves, which indirectly predicts how much the ice shelf melts. This theory is grounded in the assumption that the ocean flow beneath cavities is dominated by the rotation of the earth, and utilizes a novel quantification of seafloor obstruction of warm water inflows. We show that this theory is successful at predicting melt in simulations of ice shelves of different shapes, and in observations of real ice shelves. This work provides a theoretical grounding for melt resulting from warm subsurface waters flowing underneath Antarctic ice shelves.
Key Points
We introduce a new theoretical framework for inflow of warm water into ice shelf cavities based on geostrophically‐constrained circulation
A new metric, the Highest Unconnected Isobath (HUB), quantifies bathymetric barriers to warm water access in complex geometries
Our HUB‐informed theoretical framework is able to accurately predict melt rates across a suite of idealized models and observational data
The NHGRI-EBI GWAS Catalog (www.ebi.ac.uk/gwas) is a FAIR knowledgebase providing detailed, structured, standardised and interoperable genome-wide association study (GWAS) data to >200 000 users per ...year from academic research, healthcare and industry. The Catalog contains variant-trait associations and supporting metadata for >45 000 published GWAS across >5000 human traits, and >40 000 full P-value summary statistics datasets. Content is curated from publications or acquired via author submission of prepublication summary statistics through a new submission portal and validation tool. GWAS data volume has vastly increased in recent years. We have updated our software to meet this scaling challenge and to enable rapid release of submitted summary statistics. The scope of the repository has expanded to include additional data types of high interest to the community, including sequencing-based GWAS, gene-based analyses and copy number variation analyses. Community outreach has increased the number of shared datasets from under-represented traits, e.g. cancer, and we continue to contribute to awareness of the lack of population diversity in GWAS. Interoperability of the Catalog has been enhanced through links to other resources including the Polygenic Score Catalog and the International Mouse Phenotyping Consortium, refinements to GWAS trait annotation, and the development of a standard format for GWAS data.
Protocols of systematic reviews and meta-analyses allow for planning and documentation of review methods, act as a guard against arbitrary decision making during review conduct, enable readers to ...assess for the presence of selective reporting against completed reviews, and, when made publicly available, reduce duplication of efforts and potentially prompt collaboration. Evidence documenting the existence of selective reporting and excessive duplication of reviews on the same or similar topics is accumulating and many calls have been made in support of the documentation and public availability of review protocols. Several efforts have emerged in recent years to rectify these problems, including development of an international register for prospective reviews (PROSPERO) and launch of the first open access journal dedicated to the exclusive publication of systematic review products, including protocols (BioMed Central’s Systematic Reviews). Furthering these efforts and building on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines, an international group of experts has created a guideline to improve the transparency, accuracy, completeness, and frequency of documented systematic review and meta-analysis protocols—PRISMA-P (for protocols) 2015. The PRISMA-P checklist contains 17 items considered to be essential and minimum components of a systematic review or meta-analysis protocol.This PRISMA-P 2015 Explanation and Elaboration paper provides readers with a full understanding of and evidence about the necessity of each item as well as a model example from an existing published protocol. This paper should be read together with the PRISMA-P 2015 statement. Systematic review authors and assessors are strongly encouraged to make use of PRISMA-P when drafting and appraising review protocols.
The existence of stabilizing feedbacks within Earth's climate system is generally thought to be necessary for the persistence of liquid water and life. Over the course of Earth's history, Earth's ...atmospheric composition appears to have adjusted to the gradual increase in solar luminosity, resulting in persistently habitable surface temperatures. With limited exceptions, the Earth system has been observed to recover rapidly from pulsed climatic perturbations. Carbon dioxide (CO2) regulation via negative feedbacks within the coupled global carbon‐silica cycles are classically viewed as the main processes giving rise to climate stability on Earth. Here we review the long‐term global carbon cycle budget, and how the processes modulating Earth's climate system have evolved over time. Specifically, we focus on the relative roles that shifts in carbon sources and sinks have played in driving long‐term changes in atmospheric pCO2. We make the case that marine processes are an important component of the canonical silicate weathering feedback, and have played a much more important role in pCO2 regulation than traditionally imagined. Notably, geochemical evidence indicate that the weathering of marine sediments and off‐axis basalt alteration act as major carbon sinks. However, this sink was potentially dampened during Earth's early history when oceans had higher levels of dissolved silicon (Si), iron (Fe), and magnesium (Mg), and instead likely fostered more extensive carbon recycling within the ocean‐atmosphere system via reverse weathering—that in turn acted to elevate ocean‐atmosphere CO2 levels.
Key Points
Long term carbon sources and sinks are likely larger than traditional envisioned
There is significant silicate weathering in the marine as well as terrestrial settings
Ocean oxygenation and evolution of a biotic Si cycle forced a drop in reverse weathering rates and an increase in marine weathering rates
Normal-to-cancer (NTC) transition is known to be closely associated to cell´s biomechanical properties which are dependent on the dynamics of the intracellular medium. This study probes different ...human cancer cells (breast, prostate and lung), concomitantly to their healthy counterparts, aiming at characterising the dynamical profile of water in distinct cellular locations, for each type of cell, and how it changes between normal and cancer states. An increased plasticity of the cytomatrix is observed upon normal-to-malignant transformation, the lung carcinoma cells displaying the highest flexibility followed by prostate and breast cancers. Also, lung cells show a distinct behaviour relative to breast and prostate, with a higher influence from hydration water motions and localised fast rotations upon NTC transformation. Quasielastic neutron scattering techniques allowed to accurately distinguish the different dynamical processes taking place within these highly heterogeneous cellular systems. The results thus obtained suggest that intracellular water dynamics may be regarded as a specific reporter of the cellular conditions-either healthy or malignant.
Post-discharge surgical site infections (SSI) are a major source of morbidity, expense and anxiety for patients. However, patient perceptions about barriers experienced while seeking care for ...post-discharge SSI have not been assessed in depth. We explored patient experience of SSI and openness to a mobile health (mHealth) wound monitoring "app" as a novel solution to address this problem.
Mixed method design with semi-structured interviews and surveys. Participants were patients who had post-discharge surgical wound complications after undergoing operations with high risk of SSI, including open colorectal or ventral hernia repair surgery. The study was conducted at two affiliated teaching hospitals, including an academic medical center and a level 1 trauma center.
From interviews with 13 patients, we identified 3 major challenges that impact patients' ability to manage post-discharge surgical wound complications, including required knowledge for wound monitoring from discharge teaching, self-efficacy for wound monitoring at home, and accessible communication with their providers about wound concerns. Patients found an mHealth wound monitoring application highly acceptable and articulated its potential to provide more frequent, thorough, and convenient follow-up that could reduce post-discharge anxiety compared to the current practice. Major concerns with mHealth wound monitoring were lack of timely response from providers and inaccessibility due to either lack of an appropriate device or usability challenges.
Our findings reveal gaps and frustrations with post-discharge care after surgery which could negatively impact clinical outcomes and quality of life. To address these issues, we are developing mPOWEr, a patient-centered mHealth wound monitoring application for patients and providers to collaboratively bridge the care transition between hospital and home.
To evaluate effectively interventions to increase physical activity among older persons, reliable and valid measures of physical activity are required that can also detect the expected types of ...physical activity changes in this population. This paper describes a self-report physical activity questionnaire for older men and women, developed to evaluate the outcomes of the Community Healthy Activities Model Program for Seniors (CHAMPS), an intervention to increase physical activity.
The questionnaire assesses weekly frequency and duration of various physical activities typically undertaken by older adults. We estimated caloric expenditure/wk expended in physical activity and created a summary frequency/wk measure. We calculated measures of each of these for: 1) activities of at least moderate intensity (MET value >/= 3.0); and 2) all specified physical activities, including those of light intensity. Six-month stability was estimated on participants not likely to change (assessment-only control group, physically active cohort). Several tests of construct validity were conducted, and sensitivity to change was analyzed based on response to the CHAMPS intervention.
The sample (N = 249) comprised underactive persons (N = 173 from the CHAMPS trial) and active persons (N = 76). The sample was aged 65-90 yr (mean = 74, SD = 6); 64% were women, and 9% were minorities. Six-month stability ranged from 0.58 to 0.67, using intraclass correlation coefficients. Nearly all construct validity hypotheses were confirmed, though correlations were modest. All measures were sensitive to change (P < or = 0.01), with small to moderate effect sizes (0.38-0.64).
The CHAMPS measure may be useful for evaluating the effectiveness of programs aimed at increasing levels of physical activity in older adults.
Previous studies have suggested that the global ocean density stratification below ∼3000 m is approximately set by its direct connection to the Southern Ocean surface density, which in turn is ...constrained by the atmosphere. Here the role of Southern Ocean surface forcing in glacial‐interglacial stratification changes is investigated using a comprehensive climate model and an idealized conceptual model. Southern Ocean surface forcing is found to control the global deep ocean stratification up to ∼2000 m, which is much shallower than previously thought and contrary to the expectation that the North Atlantic surface forcing should strongly influence the ocean at intermediate depths. We show that this is due to the approximately fixed surface freshwater fluxes, rather than a fixed surface density distribution in the Southern Ocean as was previously assumed. These results suggest that Southern Ocean surface freshwater forcing controls glacial‐interglacial stratification changes in much of the deep ocean.
Key Points
Southern Ocean surface forcing controls the global deep ocean density stratification over a larger depth range than previously thought
Fixed Southern Ocean surface buoyancy fluxes rather than fixed surface density controls the deep density stratification
But the temperature and salinity components of the deep stratification are strongly influenced by Northern Hemisphere surface forcing
Objective
To determine the contribution of specific contraceptive side effects to method switch and modern‐method discontinuation among Kenyan women.
Design
A prospective cohort study.
Setting
Five ...counties in Western Kenya.
Participants
Women aged ≥18 years old and emancipated female minors ≥14 years old using modern, reversible contraception were recruited while attending 10 public health facilities.
Methods
Patient‐reported adverse effect symptoms, method switch and discontinuation were reported through weekly text message‐based surveys for 24 weeks.
Main outcome measurements
Prevalence, hazards ratio (HR).
Results
Among 825 women, 44% were using implants, 43% injectables, 7% an intrauterine device and 6% oral contraceptive pills at enrolment. Most (61%) women were continuing a method used in the previous month. During the 24‐week follow up, incidence of contraceptive switch was 61.3 per 100 person‐years (95% confidence interval CI 52.4–71.8) and incidence of discontinuation was 38.5 per 100 person‐years (95% CI 31.6–47.0). On average, one‐quarter (prevalence Pr 0.24, 95% CI 0.22–0.26) of participants reported side effects or method problems weekly, with sexual side effects the most prevalent symptom (Pr 0.15, 95% CI 0.13–0.16). Lack of expected bleeding was associated with higher risk of method switch (adjusted hazard ratio aHR 2.36, 95% CI 1.22–4.57). Risk of all‐modern method discontinuation was higher among women experiencing irregular bleeding (aHR 2.39, 95% CI 1.20–4.77), weight changes (aHR 2.72, 95% CI 1.47–4.68) and sexual side effects (aHR 2.42, 95% CI 1.40–4.20).
Conclusions
Addressing irregular bleeding, weight changes and sexual side effects through development of new products that minimise these specific side effects and anticipatory counseling may reduce method‐related discontinuation.
Tweetable
Bleeding, weight changes, sexual problems associated with discontinuation of #contraception, but many continue despite side effects.
Tweetable
Bleeding, weight changes, sexual problems associated with discontinuation of #contraception, but many continue despite side effects.
Objective
To assess the effect of short message service (SMS) communication on facility delivery, exclusive breastfeeding (EBF), and contraceptive use.
Design
Mobile WACh was a three‐arm unblinded ...individually randomised controlled trial.
Setting
A public sector maternal child health (MCH) clinic in Nairobi, Kenya.
Population
Three hundred women attending antenatal care were randomised, 100 to each arm, and followed for 24 weeks postpartum. Pregnant women, at least 14 years old with access to a mobile phone and able to read SMS were eligible for participation.
Methods
Women were randomised (1:1:1) to receive one‐way SMS versus two‐way SMS with a nurse versus control. Weekly SMS content was tailored for maternal characteristics and pregnancy or postpartum timing.
Main outcome measures
Facility delivery, EBF, and contraceptive use were compared separately between each intervention arm and the control arm by Kaplan–Meier analysis and chi‐square tests using intent‐to‐treat analyses.
Results
The overall facility delivery rate was high (98%) and did not differ by arm. Compared with controls, probability of EBF was higher in the one‐way SMS arm at 10 and 16 weeks, and in the two‐way SMS arm at 10, 16, and 24 weeks (P < 0.005 for all). Contraceptive use was significantly higher in both intervention arms by 16 weeks (one‐way SMS: 72% and two‐way SMS: 73%; P = 0.03 and P = 0.02 versus 57% control, respectively); however, this difference was not significant when correcting for multiple comparisons.
Conclusion
One‐way and two‐way SMS improved EBF practices and early contraceptive use. Two‐way SMS had an added benefit on sustained EBF, providing evidence that SMS messaging influences uptake of interventions that improve maternal and neonatal health.
Source of funding
Funding was provided by the National Institutes of Health (K12HD001264 to JAU, R01HD080460, K24HD054314 to GJS, and K01AI116298 to ALD), the National Science Foundation (Graduate Research Fellowship to TP and BD), as well as the University of Washington Global Center for Integrated Health of Women Adolescents and Children (Global WACh).
Tweetable
The Mobile WACh RCT demonstrates that SMS improved practice of exclusive breastfeeding and early postpartum contraception.
Tweetable
The Mobile WACh RCT demonstrates that SMS improved practice of exclusive breastfeeding and early postpartum contraception.
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