97 research outputs found

    Do Macroalgal Environments Leave a Geological Signature? Modern Test Case from Kaikoura, New Zealand

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    Brown, red and green macroalgae in modern temperate marine environments are ecosystem‐forming primary producers on rocky substrates, yet they have a poor preservation potential and few fossil examples are known from the rock record. Macroalgal forests, as carbonate producers, are largely unrecognised within the coolwater carbonate realm even though they host a wide variety of calcareous organisms with good preservational potential. Some species of molluscs, sea urchins and crustaceans only live within the understorey of macroalgal forests. These, and other, calcareous flora and fauna are the key to identification of macroalgae environments in the rock record. Modern macroalgae forests at Kaikoura, New Zealand, exhibit a clear zonation of calcareous components controlled by substrate topography, wave exposure, water depth and light penetration. The prominent live calcareous components include encrusting and foliose coralline red algae, molluscs, bryozoans, echinoderms, calcareous worms, ascidians and crustaceans, as well as sponges and other soft bodied invertebrates. The sediments accumulated beneath and adjacent to the algae at Kaikoura are bioclastic, terrigenous sands and gravels; with bioclasts of coralline algal fragments and rhodoliths, barnacles, molluscs, spirorbids and bryozoans. Although the shallow, wave exposed settings that promote growth of macroalgal forests are limited in areal extent, their contribution via skeletal carbonate may be considerable. In the rock record, terrigenous sands and gravels rich in coralline, barnacle, mollusc, and bryozoan fragments, that occur in association with hard‐substrate unconformities in a cool‐water realm, must be considered as representatives of past macroalgal environments

    Health-Related Quality of Life and All-Cause Mortality among Older Healthy Individuals in Australia and the United States:A Prospective Cohort Study

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    Published online: 3 January 2021PURPOSE: Previous research has demonstrated that lower health-related quality of life (HRQoL) is associated with higher morbidity and mortality, especially in-patient groups. The association of HRQoL with all-cause mortality in community samples requires further investigation. This study aimed to examine whether HRQoL predicts all-cause mortality in older healthy community-dwelling people from Australia and the United States (U.S.) enrolled in the Aspirin in Reducing Events in the Elderly (ASPREE) trial. We also explored whether this association varies by gender or country. METHOD: A prospective cohort of 19,106 individuals aged 65-98 years, who were without a dementia diagnosis or a known major life-limiting disease, and completed the 12-item short-form-HRQoL at recruitment (2010-2014). They were followed until June 2017. Cox proportional-hazard models were used to determine the association between the physical (PCS) and mental component scores (MCS) of HRQoL and all-cause mortality, adjusting for sociodemographic factors, health-related behaviours and clinical measures. Hazards ratios were estimated for every 10-unit increase in PCS or MCS. RESULTS: There were 1052 deaths over a median 4.7-years (interquartile range 3.6-5.7) of follow-up, with 11.9 events per 1000 person-years. Higher PCS was associated with lower all-cause mortality (HR 0.83, 95% CI 0.77, 0.89) in the entire sample, while higher MCS was associated with lower mortality among U.S. participants only (HR 0.78, 95% CI 0.63, 0.95). Gender differences in the association of either PCS or MCS with mortality were not observed. CONCLUSION: Our large study provides evidence that HRQoL is inversely associated with all-cause mortality among initially healthy older people.Aung Zaw Zaw Phyo, Joanne Ryan, David A. Gonzalez-Chica, Robyn L. Woods, Christopher M. Reid, Mark R. Nelson ... et al

    Evaluation of Complications and Weight Outcomes in Pediatric Cerebral Palsy Patients With Gastrostomy Tubes

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    Background: Feeding difficulties are common in children with cerebral palsy (CP). The goal of this study was to examine pediatric CP patients undergoing gastrostomy tube (G tube) placement and assess the association between patient characteristics and weight after 3 months, 6 months, and 1 year. Methods: This was a retrospective study of all pediatric patients with CP who received a G tube placement between April 2014 and December 2017 at a single institution. Bivariate analysis was used to examine association between patient characteristics and the primary outcome of improvement in weight Z score at 3, 6, and 12 months. Results: Of 63 patients who received a G tube, 81% had an increase in Z score at 3 months, 44% at 6 months, and 64% at 12 months. By 12 months, factors associated with a positive Z score change included moderate and severe malnutrition, lack of prior G tube, and fewer comorbidities. The majority (69.8%) of patients experienced complications. Seven (11%) patients died, with only 1 death related to G tube placement. Discussion: The use of G tubes in CP patients resulted in an increase in an improvement in nutritional status for the majority of patients over the course of a year. Although most complications were minor, patients had a high complication rate and frequently visited the emergency department, highlighting the need for standardized education and follow-up among this patient population

    ChatGPT sits the DFPH exam: large language model performance and potential to support public health learning

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    Background Artificial intelligence-based large language models, like ChatGPT, have been rapidly assessed for both risks and potential in health-related assessment and learning. However, their applications in public health professional exams have not yet been studied. We evaluated the performance of ChatGPT in part of the Faculty of Public Health’s Diplomat exam (DFPH). Methods ChatGPT was provided with a bank of 119 publicly available DFPH question parts from past papers. Its performance was assessed by two active DFPH examiners. The degree of insight and level of understanding apparently displayed by ChatGPT was also assessed. Results ChatGPT passed 3 of 4 papers, surpassing the current pass rate. It performed best on questions relating to research methods. Its answers had a high floor. Examiners identified ChatGPT answers with 73.6% accuracy and human answers with 28.6% accuracy. ChatGPT provided a mean of 3.6 unique insights per question and appeared to demonstrate a required level of learning on 71.4% of occasions. Conclusions Large language models have rapidly increasing potential as a learning tool in public health education. However, their factual fallibility and the difficulty of distinguishing their responses from that of humans pose potential threats to teaching and learning

    Nonclassical statistics of intracavity coupled χ(2)\chi^{(2)} waveguides: the quantum optical dimer

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    A model is proposed where two χ(2)\chi^{(2)} nonlinear waveguides are contained in a cavity suited for second-harmonic generation. The evanescent wave coupling between the waveguides is considered as weak, and the interplay between this coupling and the nonlinear interaction within the waveguides gives rise to quantum violations of the classical limit. These violations are particularly strong when two instabilities are competing, where twin-beam behavior is found as almost complete noise suppression in the difference of the fundamental intensities. Moreover, close to bistable transitions perfect twin-beam correlations are seen in the sum of the fundamental intensities, and also the self-pulsing instability as well as the transition from symmetric to asymmetric states display nonclassical twin-beam correlations of both fundamental and second-harmonic intensities. The results are based on the full quantum Langevin equations derived from the Hamiltonian and including cavity damping effects. The intensity correlations of the output fields are calculated semi-analytically using a linearized version of the Langevin equations derived through the positive-P representation. Confirmation of the analytical results are obtained by numerical simulations of the nonlinear Langevin equations derived using the truncated Wigner representation.Comment: 15 pages, 8 figures, submitted to Phys. Rev.

    The Spin-Dependent Structure Functions of Nuclei in the Meson-Nucleon Theory

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    A theoretical approach to the investigation of spin-dependent structure functions in deep inelastic scattering of polarized leptons off polarized nuclei, based on the effective meson-nucleon theory and operator product expansion method, is proposed and applied to deuteron and 3He^3He. The explicit forms of the moments of the deuteron and 3He^3He spin-dependent structure functions are found and numerical estimates of the influence of nuclear structure effects are presented.Comment: 42 pages revtex, 7 postscript figures available from above e-mail upon request. Perugia preprint DFUPG 92/9

    Lacustrine stromatolites: Useful structures for environmental interpretation – an example from the Miocene Ebro Basin

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    The significance of stromatolites as depositional environmental indicators and the underlying causes of lamination in the lacustrine realm are poorly understood. Stromatolites in a ca 600 m thick Miocene succession in the Ebro Basin are good candidates to shed light on these issues because they are intimately related to other lacustrine carbonate and sulphate facies, grew under variable environmental conditions and show distinct lamination patterns. These stromatolites are associated with wave-related, clastic-carbonate laminated limestones. Both facies consist of calcite and variable amounts of dolomite. Thin planar stromatolites (up to 10 cm thick and less than 6 m long) occurred in very shallow water. These stromatolites represented first biological colonization after: (i) subaerial exposure in the palustrine environment (i.e. at the beginning of deepening cycles); or (ii) erosion due to surge action, then coating very irregular surfaces on laminated limestones (i.e. through shallowing or deepening cycles). Sometimes they are associated with evaporative pumping. Stratiform stromatolites (10 to 30 cm high and tens of metres long) and domed stromatolites (10 to 30 cm high and long) developed in deeper settings, between the surge periods that produced hummocky cross-stratification and horizontal lamination offshore. Changes in stromatolite lamina shape, and thus in the growth forms through time, can be attributed to changes in water depth, whereas variations in lamina continuity are linked to water energy and sediment supply. Growth of the stromatolites resulted from in situ calcite precipitation and capture of minor amounts of fine-grained carbonate particles. Based on texture, four types of simple laminae are distinguished. The simple micrite and microsparite laminae can be grouped into light and dark composite laminae, which represent, respectively, high and low Precipitation/Evaporation ratio periods. Different lamination patterns provide new ideas for the interpretation of microbial laminations as a function of variations in climate-dependent parameters (primarily the Precipitation/Evaporation ratio) over variable timescales

    Atom lasers: production, properties and prospects for precision inertial measurement

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    We review experimental progress on atom lasers out-coupled from Bose-Einstein condensates, and consider the properties of such beams in the context of precision inertial sensing. The atom laser is the matter-wave analog of the optical laser. Both devices rely on Bose-enhanced scattering to produce a macroscopically populated trapped mode that is output-coupled to produce an intense beam. In both cases, the beams often display highly desirable properties such as low divergence, high spectral flux and a simple spatial mode that make them useful in practical applications, as well as the potential to perform measurements at or below the quantum projection noise limit. Both devices display similar second-order correlations that differ from thermal sources. Because of these properties, atom lasers are a promising source for application to precision inertial measurements.Comment: This is a review paper. It contains 40 pages, including references and figure

    Associations of body size with all-cause and cause-specific mortality in healthy older adults

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    In the general population, body mass index (BMI) and waist circumference are recognized risk factors for several chronic diseases and all-cause mortality. However, whether these associations are the same for older adults is less clear. The association of baseline BMI and waist circumference with all-cause and cause-specific mortality was investigated in 18,209 Australian and US participants (mean age: 75.1 ± 4.5 years) from the ASPirin in Reducing Events in the Elderly (ASPREE) study, followed up for a median of 6.9 years (IQR: 5.7, 8.0). There were substantially different relationships observed in men and women. In men, the lowest risk of all-cause and cardiovascular mortality was observed with a BMI in the range 25.0–29.9 kg/m2 [HR25-29.9 vs 21–24.9 kg/m2: 0.85; 95% CI, 0.73–1.00] while the highest risk was in those who were underweight [HRBMI <21 kg/m2 vs BMI 21–24.9 kg/m2: 1.82; 95% CI 1.30–2.55], leading to a clear U-shaped relationship. In women, all-cause mortality was highest in those with the lowest BMI leading to a J-shaped relationship (HRBMI <21 kg/m2 vs BMI 21–24.9 kg/m2: 1.64; 95% CI 1.26–2.14). Waist circumference showed a weaker relationship with all-cause mortality in both men and women. There was little evidence of a relationship between either index of body size and subsequent cancer mortality in men or women, while non-cardiovascular non-cancer mortality was higher in underweight participants. For older men, being overweight was found to be associated with a lower risk of all-cause mortality, while among both men and women, a BMI in the underweight category was associated with a higher risk. Waist circumference alone had little association with all-cause or cause-specific mortality risk. Trial registration ASPREE https://ClinicalTrials.gov number NCT01038583.Prudence R. Carr, Katherine L. Webb, Johannes T. Neumann, Le T. P. Thao, Lawrence J. Beilin, Michael E. Ernst, Bernadette Fitzgibbon, Danijela Gasevic, Mark R. Nelson, Anne B. Newman, Suzanne G. Orchard, Alice Owen, Christopher M. Reid, Nigel P. Stocks, Andrew M. Tonkin, Robyn L. Woods, John J. McNei

    The Sneeuberg: A new centre of floristic endemism on the Great Escarpment, South Africa

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    The Sneeuberg mountain complex (Eastern Cape) comprises one of the most prominent sections of the Great Escarpment in southern Africa but until now has remained one of the botanically least known regions. The Sneeuberg is a discrete orographical entity, being delimited in the east by the Great Fish River valley, in the west by the Nelspoort Interval, to the south by the Plains of Camdeboo, and to the north by the Great Karoo pediplain. The highest peaks range from 2278 to 2504 m above sea level, and the summit plateaux range from 1800 to 2100 m. Following extensive literature review and a detailed collecting programme, the Sneeuberg is reported here as having a total flora of 1195 species of which 107 (9%) are alien species, 33 (2.8%) are endemic, and 13 (1.1%) near-endemic. Five species previously reported as Drakensberg Alpine Centre (DAC) endemics are now known to occur in the Sneeuberg (representing range extensions of some 300–500 km). One-hundred-and-five species (8.8%) are DAC near-endemics, with the Sneeuberg being the western limit for most of these. Ten species (0.8%) represent disjunctions across the Karoo Interval from the Cape Floristic Region (CFR) to the Sneeuberg. In all, some 23 significant range extensions, eight new species, and several rediscoveries are recorded. We conclude by recognising the Sneeuberg as a new centre of endemism along the Great Escarpment, with floristic affinities with the Albany Centre and the DAC, and links to the CFR
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