Late Jurassic to Early Cretaceous stable isotope and geochemical records from the northern high latitudes: implications for palaeoclimate

Merged with duplicate record 10026.1/861 on 07.03.2017 by CS (TIS)The Jurassic and Cretaceous periods are widely accepted as being dominated by greenhouse conditions with elevated CO2 levels and warm polar regions. Although much compelling evidence to support this idea of global warmth exists, some recent studies propose that the greenhouse climate may at times have been punctuated by sub-freezing polar conditions and the presence of limited polar ice. The evidence, however, is somewhat equivocal and is both spatially and temporally limited with much of this research until now being concentrated in mid- to low latitudes, despite it being generally accepted that global climate is defined to a significant degree by prevailing conditions at the poles. Existing data are also often plagued by poor sampling resolutions and dubious diagenetic histories. This research presents the first extensive stable isotope and geochemical investigation of well-preserved belemnite rostra from the Callovian-Hauterivian Boreal Realm. Belemnites of the genera Cylindroteuthis, Pachyteuthis, Acroteuthis, Lagonibelus and occasionally Belemnopsis were investigated. Preservation was assessed using Backscattered Scanning Electron Microscopy, Cathodoluminescence, carbonate staining and trace element techniques. Organic carbon isotope analysis of fossilised wood was also undertaken where possible. Material from Staffin Bay, Isle of Skye, and Helmsdale, Sutherland, Scotland; the Izhma River, Timan-Pechora Basin, Russia; the Boyarka River, Yenisei-IChatanga Basin, Siberia; and Festningen and Janusfjellet, Svalbard was analysed. The carbon isotope data record relatively positive values in the Oxfordian, followed by a gradual shift towards more negative values through the Kimmeridgian and into the Volgian/Tithonian. A distinct Late Valanginian positive carbon isotope excursion is identified in both the marine carbonate and terrestrial organic carbon records from the Izhma and Boyarka rivers. The excursion occurs at a time of relatively low sea level in Russia and Siberia. The exposure and erosion of lowland areas and restricted ocean circulation (and therefore enhanced stratification) associated with a period of sea-level lowstand may account for increased rates of organic carbon burial. The Late Valanginian positive carbon isotope excursion is coeval with a distinct cooling in the Russian Izhma River succession. This could be explained by a fall in atmospheric CO2 concentration and a subsequent drop in temperature as the result of significant burial of sediments rich in organic carbon. Further evidence for cold conditions during the Valanginian interval comes from glendonites and dropstones, which were identified on Svalbard. High latitude warmth is most likely the norm for the Late Jurassic and Early Cretaceous interval, although this warmth is likely to have been punctuated by cold conditions providing the opportunity for the development of at least a seasonal cover of polar ice. The oxygen isotope data record the occurrence of cold episodes during the Lower Oxfordian Cordatum Zone, the mid-Ryazanian Kochi-Analogits zones and the Upper Valanginian Bidichotomus Zone. Palaeotemperatures as low as 2°C were calculated, providing strong evidence for the existence of cold polar conditions at theses times. Ultimately, climatic instability is probably the key characteristic of this greenhouse interval

The characterisation of oestrogen receptors by gel filtration in hormone-sensitive tissues: immature rat uterus, brain and thymus

The aims of this project were to investigate the binding characteristics of the cytosolic oestrogen receptor in the uterus, brain and thymus of immature Wistar rats. The specificities of the receptor in the uterus are well established. The specificities of the cytosolic receptor in the uterus and thymus of immature female Wistar rats were tested against a range of steroids and the values found for the thymus compared with those for the uterus. The concentrations and dissociation constant (Kd) of the cytosolic oestrogen receptor were determined in uterus, brain and thymus of male and female rats at 5,18 and 30 days of age. Clomiphene citrate (CC), an oestrogen antagonist/partial agonist, oestradiol (E2), CC+E2 or 4-hydroxyandrostenedione (4-OHA), an aromatase inhibitor, were administered to animals at 15 days in order to study the effects of these compounds on receptor binding characteristics at 30 days. Significant differences in specificity were found between the thymus and uterus, the cytosolic oestrogen receptor in the thymus exhibited significantly higher affinity for corticosterone than it did in the uterus. Male animals were heavier than females at 30 days. Uterus and thymus weights increased exponentially between 5 and 30 days. The tissue-to-body weight ratio increased in uterus between 18 and 30 days and increased in the thymus in both sexes between 5 and 18 days. In males at 30 days, the tissue-to-body weight ratio of the thymus was significantly lower than in females of the same age. Cytosolic oestrogen receptor concentrations in the uterus, brain and thymus differed between some age and/or sex groups. Cytosolic oestrogen receptor concentrations increased exponentially in the uterus between the different age groups. Cytosolic oestrogen receptor concentrations in both thymus and hypothalamus at 5 days were significantly higher in females than in males of the same age group. No differences in cytosolic oestrogen receptor concentrations were found between the sexes in the cortex at 5 and 18 days but at 30 days, receptors were not detectable in this brain area. The Kd for moxestrol, a synthetic oestrogen agonist that is not bound by alphafetoprotein present in the blood of immature rats, was similar in all tissues. E2 and CC+E2 treatments resulted in decreased body and thymus weight in both sexes, increased uterus weight and decreased thymus weight in both sexes but led to increased uterus weight. CC treatment decreased the concentration of the receptors in the female thymus only; E2 and CC+E2 treatments decreased the concentratIon of the receptor to levels that were undetectable in hypothalamus and thymus in both sexes, 4-OHA treatment increased thymus weight and cytosolic receptor concentrations in the hypothalamus and thymus of males only. These results suggest that cytosolic oestrogen receptors in uterus, brain and thymus are similar and that sex differences in these tissues are mediated by differential exposure to oestradiol during the early postnatal period. The thymus is crucial to the development of the immune response. The finding that the cytosolic oestrogen receptor differed from the uterus receptor in its affinity for corticosterone and that sex differences in cytosolic oestrogen receptor concentrations were present in the thymus at 5 days could be relevant to the sex dimorphisms that exist in autoirnmune disease manifestation

Risk of Tooth Loss After Cigarette Smoking Cessation

INTRODUCTION. Little is known about the effect of cigarette smoking cessation on risk of tooth loss. We examined how risk of tooth loss changed with longer periods of smoking abstinence in a prospective study of oral health in men. METHODS. Research subjects were 789 men who participated in the Veterans Administration Dental Longitudinal Study from 1968 to 2004. Tooth status and smoking status were determined at examinations performed every 3 years, for a maximum follow-up time of 35 years. Risk of tooth loss subsequent to smoking cessation was assessed sequentially at 1-year intervals with multivariate proportional hazards regression models. Men who never smoked cigarettes, cigars, or pipes formed the reference group. Hazard ratios were adjusted for age, education, total pack-years of cigarette exposure, frequency of brushing, and use of floss. RESULTS. The hazard ratio for tooth loss was 2.1 (95% confidence interval [CI], 1.5-3.1) among men who smoked cigarettes during all or part of follow-up. Risk of tooth loss among men who quit smoking declined as time after smoking cessation increased, from 2.0 (95% CI, 1.4-2.9) after 1 year of abstinence to 1.0 (95% CI, 0.5-2.2) after 15 years of abstinence. The risk remained significantly elevated for the first 9 years of abstinence but eventually dropped to the level of men who never smoked after 13 or more years. CONCLUSION. These results indicate that smoking cessation is beneficial for tooth retention, but long-term abstinence is required to reduce the risk to the level of people who have never smoked.U.S. Department of Veterans Affairs Epidemiology (Merit Review grant); Massachusetts Veterans Epidemiology Research and Information Center; National Institutes of Health (R01 DA10073, R03 DE016357, R15 DE12644, K24 DE00419

The Role of Hope with School Aged Children

Hope has been defined as "the sum of perceived capabilities to produce routes to desired goals, along with the perceived motivation to use those routes" (Snyder, 2000 p. 8). Hope has the potential to influence several aspects of a child's life. The purpose of this study is to examine the relationship between a child's hope, quality of life, and spirituality. This research study explores how children utilize hope in their everyday life. Participants answered three surveys, Children's Hope Scale, KINDLr, and Youth Spirituality Scale (YSS) and drew their interpretation of Hope. A total of 23 school aged children participated in the study. Participants were in grades first through seventh, ages seven to twelve years. Findings revealed significant correlation between hope and quality of life (r = .571) and hope and spirituality (r = .422). Further analysis revealed significant correlations between Hope sub-scores, agency thinking and pathways, and Quality of life sub-scores. In addition, results revealed the agency thinking and pathways coincide with each other on several dimensions of a child's quality of life. Children's scores on the HOPE scale predicted spirituality, as measured by the YSS, F=4.55 (p=.05) and quality of life, as measured by the KINDLr, F=10.12 (p=.004). Children's drawings revealed numerous, positive, and diverse themes including kindness and compassion towards others, motivation/validation, on-going belief in self, healing/recovery, and, religious

The general population cohort in rural south-western Uganda: a platform for communicable and non-communicable disease studies.

The General Population Cohort (GPC) was set up in 1989 to examine trends in HIV prevalence and incidence, and their determinants in rural south-western Uganda. Recently, the research questions have included the epidemiology and genetics of communicable and non-communicable diseases (NCDs) to address the limited data on the burden and risk factors for NCDs in sub-Saharan Africa. The cohort comprises all residents (52% aged ≥13years, men and women in equal proportions) within one-half of a rural sub-county, residing in scattered houses, and largely farmers of three major ethnic groups. Data collected through annual surveys include; mapping for spatial analysis and participant location; census for individual socio-demographic and household socioeconomic status assessment; and a medical survey for health, lifestyle and biophysical and blood measurements to ascertain disease outcomes and risk factors for selected participants. This cohort offers a rich platform to investigate the interplay between communicable diseases and NCDs. There is robust infrastructure for data management, sample processing and storage, and diverse expertise in epidemiology, social and basic sciences. For any data access enquiries you may contact the director, MRC/UVRI, Uganda Research Unit on AIDS by email to [email protected] or the corresponding author

Bacterial quorum-sensing signal arrests phytoplankton cell division and impacts virus-induced mortality

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pollara, S. B., Becker, J. W., Nunn, B. L., Boiteau, R., Repeta, D., Mudge, M. C., Downing, G., Chase, D., Harvey, E. L., & Whalen, K. E. Bacterial quorum-sensing signal arrests phytoplankton cell division and impacts virus-induced mortality. Msphere, 6(3), (2021): e00009-21, https://doi.org/10.1128/mSphere.00009-21.Interactions between phytoplankton and heterotrophic bacteria fundamentally shape marine ecosystems by controlling primary production, structuring marine food webs, mediating carbon export, and influencing global climate. Phytoplankton-bacterium interactions are facilitated by secreted compounds; however, linking these chemical signals, their mechanisms of action, and their resultant ecological consequences remains a fundamental challenge. The bacterial quorum-sensing signal 2-heptyl-4-quinolone (HHQ) induces immediate, yet reversible, cellular stasis (no cell division or mortality) in the coccolithophore Emiliania huxleyi; however, the mechanism responsible remains unknown. Using transcriptomic and proteomic approaches in combination with diagnostic biochemical and fluorescent cell-based assays, we show that HHQ exposure leads to prolonged S-phase arrest in phytoplankton coincident with the accumulation of DNA damage and a lack of repair despite the induction of the DNA damage response (DDR). While this effect is reversible, HHQ-exposed phytoplankton were also protected from viral mortality, ascribing a new role of quorum-sensing signals in regulating multitrophic interactions. Furthermore, our data demonstrate that in situ measurements of HHQ coincide with areas of enhanced micro- and nanoplankton biomass. Our results suggest bacterial communication signals as emerging players that may be one of the contributing factors that help structure complex microbial communities throughout the ocean.Funding for this work was supported by an NSF grant (OCE-1657808) awarded to K.E.W. and E.L.H. K.E.W. was also supported by a faculty research grant from Haverford College as well as funding from the Koshland Integrated Natural Science Center and Green Fund at Haverford College. E.L.H. was also supported by a Sloan Foundation research fellowship. B.L.N. was supported by an NSF grant (OCE-1633939). M.C.M. was supported by an NIH training grant (T32 HG000035). Mass spectrometry was partially supported by the University of Washington Proteomics Resource (UWPR95794). D.R. was supported by funding through the Gordon and Betty Moore Foundation (grant 6000), a Simons Collaboration for Ocean Processes and Ecology grant (329108), and an NSF grant (OCE-1736280). R.B. was supported by an NSF graduate research fellowship and an NSF grant (OCE-1829761)

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care