1,837 research outputs found

    Diffuse venting at the ASHES hydrothermal field : heat flux and tidally modulated flow variability derived from in situ time-series measurements

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    Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 17 (2016): 1435–1453, doi:10.1002/2015GC006144.Time-series measurements of diffuse exit-fluid temperature and velocity collected with a new, deep-sea camera, and temperature measurement system, the Diffuse Effluent Measurement System (DEMS), were examined from a fracture network within the ASHES hydrothermal field located in the caldera of Axial Seamount, Juan de Fuca Ridge. The DEMS was installed using the HOV Alvin above a fracture near the Phoenix vent. The system collected 20 s of 20 Hz video imagery and 24 s of 1 Hz temperature measurements each hour between 22 July and 2 August 2014. Fluid velocities were calculated using the Diffuse Fluid Velocimetry (DFV) technique. Over the ∼12 day deployment, median upwelling rates and mean fluid temperature anomalies ranged from 0.5 to 6 cm/s and 0°C to ∼6.5°C above ambient, yielding a heat flux of 0.29 ± 0.22 MW m−2 and heat output of 3.1± 2.5 kW. Using a photo mosaic to measure fracture dimensions, the total diffuse heat output from cracks across ASHES field is estimated to be 2.05 ± 1.95 MW. Variability in temperatures and velocities are strongest at semidiurnal periods and show significant coherence with tidal height variations. These data indicate that periodic variability near Phoenix vent is modulated both by tidally controlled bottom currents and seafloor pressure, with seafloor pressures being the dominant influence. These results emphasize the importance of local permeability on diffuse hydrothermal venting at mid-ocean ridges and the need to better quantify heat flux associated with young oceanic crust.NSF Grant Numbers: OCE-1131772, OCE-1131455, OCE-1337473; University of Washington, and the NSF award Grant Number: OCE-09579382016-10-2

    Navigational infrastructure at the East Pacific Rise 9°50′N area following the 2005–2006 eruption : seafloor benchmarks and near-bottom multibeam surveys

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    Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 9 (2008):Q11T04, doi:10.1029/2008GC002070.Four seafloor benchmarks were deployed with ROV Jason2 at frequently visited areas along the northern East Pacific Rise (NEPR) ridge crest near 9°50′N, within the Ridge2000 EPR integrated study site (ISS) bull's eye. When used in concert with established deep-ocean acoustic positioning techniques, these benchmarks provide navigational infrastructure to facilitate the integration of near-bottom data at this site by allowing efficient and quantitative coregistration of data and observations collected on multiple dives and over multiple cruises. High-resolution, near-bottom multibeam bathymetric surveys also were conducted along and across the ridge crest to provide a morphological and geological context for the benchmark areas. We describe the navigation and data processing techniques used to constrain the benchmark positions and outline operational details to effectively use benchmarks at this and other deep-ocean sites where multidisciplinary time series studies are conducted. The well-constrained positions of the benchmarks provide a consistent geospatial framework that can be used to limit navigational uncertainties during seafloor sampling and mapping programs and enable accurate spatial coregistration and integration of observations. These data are important to test a range of multidisciplinary hypotheses that seek to link geological, chemical, and biological processes associated with crustal accretion and energy transfer from the mantle to the hydrosphere at mid-ocean ridges

    Neonatal Lipopolysaccharide Exposure Delays Puberty and Alters Hypothalamic Kiss1 and Kiss1r mRNA Expression in the Female Rat

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    Immunological challenge experienced in early life can have long-term programming effects on the hypothalamic-pituitary-adrenal axis that permanently influence the stress response. Similarly, neonatal exposure to immunological stress enhances stress-induced suppression of the hypothalamic-pituitary gonadal (HPG) axis in adulthood, but may also affect earlier development, including the timing of puberty. To investigate the timing of the critical window for this programming of the HPG axis, neonatal female rats were injected with lipopolysaccharide (LPS; 50 μg/kg i.p.) or saline on postnatal days 3 + 5, 7 + 9, or 14 + 16 and monitored for vaginal opening and first vaginal oestrus as markers of puberty. We also investigated the effects of neonatal programming on the development of the expression patterns of kisspeptin (Kiss1) and its receptor (Kiss1r) in hypothalamic sites known to contain kisspeptin-expressing neuronal populations critical to reproductive function: the medial preoptic area (mPOA) and the arcuate nucleus in neonatally-stressed animals. We determined that the critical period for a significant delay in puberty as a result of neonatal LPS exposure is before 7 days of age in the female rat, and demonstrated that Kiss1, but not Kiss1r mRNA, expression in the mPOA is down-regulated in pre-pubertal females. These data suggest that the mPOA population of kisspeptin neurones play a pivotal role in controlling the onset of puberty, and that their function can be affected by neonatal stress

    Predicting sexual problems in women: The relevance of sexual excitation and sexual inhibition

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    This is the post-print version of the article. The official published version can be obtained from the link below.Data from a non-clinical sample of 540 heterosexual women were used to examine the relationships between scores on the Sexual Excitation/Sexual Inhibition Inventory for Women (SESII-W) and ratings of current sexual problems, lifetime arousal difficulty, lifetime orgasm difficulty, and lifetime problems with low sexual interest. Multiple regression analyses also included several demographic/background variables as predictors: age, full-time employment, completed college, children in household, married, health ratings, importance of sex, and whether the woman was in a sexual relationship. The strongest statistical predictors of both current and lifetime sexual problems were the SESII-W inhibition factors Arousal Contingency and Concerns about Sexual Function. Demographic factors did not feature largely in any of the models predicting sexual problems even when statistically significant relationships were found. If future research supports the predictive utility of the SESII-W in identifying women who are more likely to experience sexual difficulties, these scales may be used as prognostic factors in treatment studies.This study was funded, in part, by a grant from the Lilly Centre for Women's Health

    An examination of health care utilization during the COVID-19 pandemic among women with early-stage hormone receptor-positive breast cancer

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    Background: Women undergoing treatment for breast cancer require frequent clinic visits for maintenance of therapy. With COVID-19 causing health care disruptions, it is important to learn about how this population’s access to health care has changed. This study compares self-reported health care utilization and changes in factors related to health care access among women treated at a cancer center in the mid-South US before and during the pandemic. Methods: Participants (N = 306) part of a longitudinal study to improve adjuvant endocrine therapy (AET) adherence completed pre-intervention baseline surveys about their health care utilization prior to AET initiation. Questions about the impact of COVID-19 were added after the pandemic started assessing financial loss and factors related to care. Participants were categorized into three time periods based on the survey completion date: (1) pre-COVID (December 2018 to March 2020), (2) early COVID (April 2020 – December 2020), and later COVID (January 2021 to June 2021). Negative binomial regression analyses used to compare health care utilization at different phases of the pandemic controlling for patient characteristics. Results: Adjusted analyses indicated office visits declined from pre-COVID, with an adjusted average of 17.7 visits, to 12.1 visits during the early COVID period (p = 0.01) and 9.9 visits during the later COVID period (p < 0.01). Hospitalizations declined from an adjusted average 0.45 admissions during early COVID to 0.21 during later COVID, after vaccines became available (p = 0.05). Among COVID period participants, the proportion reporting changes/gaps in health insurance coverage increased from 9.5% participants during early-COVID to 14.8% in the later-COVID period (p = 0.05). The proportion reporting financial loss due to the pandemic was similar during both COVID periods (34.3% early- and 37.7% later-COVID, p = 0.72). The proportion of participants reporting delaying care or refilling prescriptions decreased from 15.2% in early-COVID to 4.9% in the later-COVID period (p = 0.04). Conclusion: COVID-19 caused disruptions to routine health care for women with breast cancer. Patients reported having fewer office visits at the start of the pandemic that continued to decrease even after vaccines were available. Fewer patients reported delaying in-person care as the pandemic progressed.National Cancer Institute ; Division of Cancer Prevention, National Cancer Institute ; Center for Strategic Scientific Initiatives, National Cancer Institute ; Division of Cancer Epidemiology and Genetics, National Cancer Institut

    Relationship between red blood cell lifespan and endogenous carbon monoxide in the common bottlenose dolphin and beluga

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    Certain deep-diving marine mammals (i.e., northern elephant seal (Mirounga angustirosis), Weddell seal (Leptonychotes weddellii)) have blood carbon monoxide (CO) levels that are comparable to those of chronic cigarette smokers. Most CO produced in humans is a by-product of heme degradation, which is released when red blood cells (RBC) are destroyed. Elevated CO can occur in humans when RBC lifespan decreases. The contribution of RBC turnover to CO concentrations in marine mammals is unknown. Here, we report the first RBC lifespans in two healthy, marine mammal species with different diving capacities and heme stores, the shallow diving bottlenose dolphin (Tursiops truncatus) and deep-diving beluga (Delphinapterus leucas) and relate the lifespans to the levels of CO in blood and breath. The belugas, with high blood heme stores, had the longest mean RBC lifespan compared to humans and bottlenose dolphins. Both cetacean species were found to have three times higher blood CO content compared to humans. The estimated CO production rate from heme degradation indicates some marine mammals may have additional mechanisms for CO production, or delay CO removal from the body, potentially from long duration breath-holds

    British OsteoNEcrosis Study (BONES) protocol: a prospective cohort study to examine the natural history of osteonecrosis in older children, teenagers and young adults with acute lymphoblastic leukaemia and lymphoblastic lymphoma

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    Introduction: Osteonecrosis is a well-recognised treatment-related morbidity risk in patients diagnosed with acute lymphoblastic leukaemia (ALL) and lymphoblastic lymphoma (LBL), with a high rate of affected patients requiring surgical intervention. Patients may have asymptomatic changes on imaging studies that spontaneously regress, and little is known about the natural history of osteonecrotic changes seen. The main aim of the British OsteoNEcrosis Study (BONES) is to determine the incidence of symptomatic and asymptomatic osteonecrosis in the lower extremities of survivors of ALL or LBL diagnosed aged 10–24 years in the UK at different time points in their treatment. This study also aims to identify risk factors for progression and the development of symptomatic osteonecrosis in this population, as well as specific radiological features that predict for progression or regression in those with asymptomatic osteonecrosis Methods and analysis: BONES is a prospective, longitudinal cohort study based at principal treatment centres around the UK. Participants are patients aged 10–24 years diagnosed with ALL or LBL under standard criteria. Assessment for osteonecrosis will be within 4 weeks of diagnosis, at the end of delayed intensification and 1, 2 and 3 years after the start of maintenance therapy. Assessment will consist of MRI scans of the lower limbs and physiotherapy assessment. Clinical and biochemical data will be collected at each of the time points. Bone mineral density data and vertebral fracture assessment using dual-energy X-ray absorptiometry will be collected at diagnosis and annually for 3 years after diagnosis of malignancy. Ethics and dissemination: Ethical approval has been obtained through the Yorkshire and Humber Sheffield Research Ethics Committee (reference number: 16/YH/0206). Study results will be published on the study website, in peer-reviewed journals and presented at relevant conferences and via social media. Trial registration number: NCT02598401; Pre-results
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