717 research outputs found

    'Thank you for loving me': A qualitative study on perceptions of gratitude and their effects in palliative care patients and relatives.

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    Empirical studies suggest that gratitude positively influence the quality of life of palliative patients and relatives. However, the literature is marked by a lack of conceptual clarity about what gratitude is and whether it can bring about individual and social benefits. This paper explores how palliative care patients and relatives understand gratitude, how discursive representations of gratitude may affect their positions, perceptions and relations, and how to conceptualise gratitude in the palliative context. We examine 33 gratitude letters written by patients and relatives and 25 semi-structured interviews conducted as part of a pilot gratitude intervention study. We use a qualitative approach, thematic analysis, within a conceptual framework of discourse analysis. Data were collected from 23 patients and 13 relatives recruited through three hospital palliative care services in French-speaking Switzerland. Participants articulate gratitude in five ways: (1) appreciating others; (2) love; (3) need to reciprocate; (4) appreciating the little things; (5) solace amid serious illness. While some of these representations are sources of positive emotions and outlook, wellbeing and hope, others may confirm self-perceptions of powerlessness and burden. These results support a tridimensional conceptualisation of gratitude in palliative care as source of individual benefits, valuing closest relationships and moral obligation. Our study suggests that gratitude is a key to a good (end of) life, whilst highlighting potential negative effects. It could help healthcare professionals to better understand what gratitude means to patients and relatives, which may facilitate awareness and fostering of gratitude in palliative care

    Real-time PCR reveals a high incidence of Symbiodinium clade D at low levels in four scleractinian corals across the Great Barrier Reef:Implications for symbiont shuffling

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    Reef corals form associations with an array of genetically and physiologically distinct endosymbionts from the genus Symbiodinium. Some corals harbor different clades of symbionts simultaneously, and over time the relative abundances of these clades may change through a process called symbiont shuffling. It is hypothesized that this process provides a mechanism for corals to respond to environmental threats such as global warming. However, only a minority of coral species have been found to harbor more than one symbiont clade simultaneously and the current view is that the potential for symbiont shuffling is limited. Using a newly developed real-time PCR assay, this paper demonstrates that previous studies have underestimated the presence of background symbionts because of the low sensitivity of the techniques used. The assay used here targets the multi-copy rDNA ITS1 region and is able to detect Symbiodinium clades C and D with > 100-fold higher sensitivity compared to conventional techniques. Technical considerations relating to intragenomic variation, estimating copy number and non-symbiotic contamination are discussed. Eighty-two colonies from four common scleractinian species (Acropora millepora, Acropora tenuis, Stylophora pistillata and Turbinaria reniformis) and 11 locations on the Great Barrier Reef were tested for background Symbiodinium clades. Although these colonies had been previously identified as harboring only a single clade based on SSCP analyses, background clades were detected in 78% of the samples, indicating that the potential for symbiont shuffling may be much larger than currently thought

    Branching coral growth and visual health during bleaching and recovery on the central Great Barrier Reef

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    Coral reefs are under threat from cumulative impacts such as cyclones, crown-of-thorns starfish (COTS) outbreaks and climate-driven coral bleaching events. Branching corals are more severely impacted by these events than other coral morphologies due to their sensitivity to heat stress and weaker skeletons and COTS preferred prey. The central Great Barrier Reef experienced unprecedented back-to-back bleaching events in 2016 and 2017. This study commenced in 2017 at the peak of heat stress and examined the impact of the heatwave on the survival and recovery of corals by assessing the growth, health (based on the visual health index) and physiological parameters (chlorophyll a, zooxanthellae density, lipid and protein content) of two species, Acropora millepora and Pocillopora acuta (N = 60 colonies for each species). It was conducted across a gradient of turbidity at three reefs, Pandora, Orpheus and Rib, that experienced in April 2017, degree heating weeks (DHW) of 9, 8 and 7, respectively. Orpheus experienced the worst bleaching, based on visual health score, followed by Rib and Pandora. Rib experienced the greatest mortality (78% by Nov 2017); however, this was attributed to the presence of actively feeding crown-of-thorns starfish. Growth rates of A. millepora were almost twice the rate of P. acuta. Both species showed significant seasonal variation with growth of A. millepora and P. acuta 35–40% and 23–33% significantly greater in the summer, respectively. Differences in growth rates were best explained by indicators of energy acquisition. For example, the most important predictor variable in determining higher growth rates and visual health score in A. millepora was chlorophyll a content. For P. acuta, visual health score was the best predictor variable for higher growth rates. This study highlights the important role that chlorophyll a and associated symbionts play in growth and survival in these corals during and after a heat stress event

    Parameter estimation for biochemical reaction networks using Wasserstein distances

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    We present a method for estimating parameters in stochastic models of biochemical reaction networks by fitting steady-state distributions using Wasserstein distances. We simulate a reaction network at different parameter settings and train a Gaussian process to learn the Wasserstein distance between observations and the simulator output for all parameters. We then use Bayesian optimization to find parameters minimizing this distance based on the trained Gaussian process. The effectiveness of our method is demonstrated on the three-stage model of gene expression and a genetic feedback loop for which moment-based methods are known to perform poorly. Our method is applicable to any simulator model of stochastic reaction networks, including Brownian Dynamics.Comment: 22 pages, 8 figures. Slight modifications/additions to the text; added new section (Section 4.4) and Appendi

    Near-to mid-IR spectral purity transfer with a tunable frequency comb: methanol frequency metrology over a record frequency span

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    We report the development and operation of a frequency-comb-assisted high-resolution mid-infrared molecular spectrometer combining high spectral purity, SI-traceability, wide tunability and high sensitivity. An optical frequency comb is used to transfer the spectral purity of a SI-traceable 1.54 μ\mum metrology-grade frequency reference to a 10.3 μ\mum quantum cascade laser (QCL). The near-infrared reference is operated at the French time/frequency metrology institute, calibrated there to primary frequency standards, and transferred to Laboratoire de Physique des Lasers via the REFIMEVE fiber network. The QCL exhibits a sub-10 --15 frequency stability from 0.1 to 10 s and its frequency is traceable to the SI with a total uncertainty better than 4 x 10 --14 after 1-s averaging time. We have developed the instrumentation allowing comb modes to be continuously tuned over 9 GHz resulting in a QCL of record spectral purity uninterruptedly tunable at the precision of the reference over an unprecedented span of 1.4 GHz. We have used our apparatus to conduct sub-Doppler spectroscopy of methanol in a multi-pass cell, demonstrating state-of-art frequency uncertainties down to the few kilohertz level. We have observed weak intensity resonances unreported so far, resolved subtle doublets never seen before and brought to light discrepancies with the HITRAN database. This demonstrates the potential of our apparatus for probing subtle internal molecular processes, building accurate spectroscopic models of polyatomic molecules of atmospheric or astrophysical interest, and carrying out precise spectroscopic tests of fundamental physics

    Commentary: reconstructing four centuries of temperature-induced coral bleaching on the great barrier reef

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    Coral reefs are spectacular ecosystems found along tropical coastlines where they provide goods and services to hundreds of millions of people. While under threat from local factors, coral reefs are increasingly susceptible to ocean warming from anthropogenic climate change. One of the signature disturbances is the large-scale, and often deadly, breakdown of the symbiosis between corals and dinoflagellates. This is referred to as mass coral bleaching and often causes mass mortality. The first scientific records of mass bleaching date to the early 1980s (Hoegh-Guldberg et al., 2017). Kamenos and Hennige (2018, hereafter KH18), however, claim to show that mass coral bleaching is not a recent phenomenon, and has occurred regularly over the past four centuries (1572–2001) on the Great Barrier Reef (GBR), Australia. They support their claim by developing a putative proxy for coral bleaching that uses the suggested relationship between elevated sea surface temperatures (SSTs) and reduced linear extension rates of 44 Porites spp. coral cores from 28 GBR reefs. If their results are correct, then mass coral bleaching events have been a frequent feature for hundreds of years in sharp contrast to the vast majority of scientific evidence. There are, however, major flaws in the KH18 methodology. Their use of the Extended Reconstructed Sea Surface Temperature (ERSST) dataset (based on ship and buoy observations) for reef temperatures from 1854 to 2001, ignores the increasing unreliability of these data which become sparse, less rigorous, and more interpolated going back in time. To demonstrate how the quality of these data degrades, we plot the average number of SST observations per month that contribute to each 200 x 200 km ERSST pixel (Figure 1A, black line). Note that from 1854 to 1900 the four ERSST pixels used by KH18 averaged only 0.85 observations per month, and 82% of these months had no observations at all. Given the heterogeneous nature of SST at local and regional levels, using such broad-scale data as ERSST, is likely to produce substantial errors at reef scales (Figure 1A, red line prior to 1900)

    Climate change promotes parasitism in a coral symbiosis.

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    Coastal oceans are increasingly eutrophic, warm and acidic through the addition of anthropogenic nitrogen and carbon, respectively. Among the most sensitive taxa to these changes are scleractinian corals, which engineer the most biodiverse ecosystems on Earth. Corals' sensitivity is a consequence of their evolutionary investment in symbiosis with the dinoflagellate alga, Symbiodinium. Together, the coral holobiont has dominated oligotrophic tropical marine habitats. However, warming destabilizes this association and reduces coral fitness. It has been theorized that, when reefs become warm and eutrophic, mutualistic Symbiodinium sequester more resources for their own growth, thus parasitizing their hosts of nutrition. Here, we tested the hypothesis that sub-bleaching temperature and excess nitrogen promotes symbiont parasitism by measuring respiration (costs) and the assimilation and translocation of both carbon (energy) and nitrogen (growth; both benefits) within Orbicella faveolata hosting one of two Symbiodinium phylotypes using a dual stable isotope tracer incubation at ambient (26 °C) and sub-bleaching (31 °C) temperatures under elevated nitrate. Warming to 31 °C reduced holobiont net primary productivity (NPP) by 60% due to increased respiration which decreased host %carbon by 15% with no apparent cost to the symbiont. Concurrently, Symbiodinium carbon and nitrogen assimilation increased by 14 and 32%, respectively while increasing their mitotic index by 15%, whereas hosts did not gain a proportional increase in translocated photosynthates. We conclude that the disparity in benefits and costs to both partners is evidence of symbiont parasitism in the coral symbiosis and has major implications for the resilience of coral reefs under threat of global change

    Systematically missing confounders in individual participant data meta-analysis of observational cohort studies.

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    One difficulty in performing meta-analyses of observational cohort studies is that the availability of confounders may vary between cohorts, so that some cohorts provide fully adjusted analyses while others only provide partially adjusted analyses. Commonly, analyses of the association between an exposure and disease either are restricted to cohorts with full confounder information, or use all cohorts but do not fully adjust for confounding. We propose using a bivariate random-effects meta-analysis model to use information from all available cohorts while still adjusting for all the potential confounders. Our method uses both the fully adjusted and the partially adjusted estimated effects in the cohorts with full confounder information, together with an estimate of their within-cohort correlation. The method is applied to estimate the association between fibrinogen level and coronary heart disease incidence using data from 154,012 participants in 31 cohort

    Synthesis and structure of polymorph B of zeolite Beta

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    [EN] It was found that either polymorph B or polymorph C of zeolite beta can be obtained from the same structure directing agent: 4,4-dimethyl-4-azonia-tricyclo[5.2.2.0(2,6)] undec-8-ene hydroxide. The synthesis occurs through a consecutive process where polymorph B is first formed and then transformed into polymorph C. It is possible to produce a zeolite highly enriched in polymorph B, provided that the transformation of this phase into polymorph C is slowed down up to the point where polymorph C is only detected at trace levels. The structure of polymorph B was determined for the first time by electron crystallography with SAED and HRTEM from areas of unfaulted polymorph B crystals.Financial support from the Spanish Government (Project MAT2006-14274-C02–01) and the EU Commission (TOPCOMBI Project) is gratefully acknowledged. M.M. thanks CSIC for an I3P grant. J.S. is supported by a postdoctoral grant from the Carl Trygger Foundation. The Berzelii Centre EXSELENT is supported by the Swedish Research Council (VR) and the Swedish Governmental Agency for Innovation Systems (VINNOVA).Corma Canós, A.; Moliner Marin, M.; Cantin Sanz, A.; Díaz Cabañas, MJ.; Jorda Moret, JL.; Zhang, D.; Sun, J.... (2008). Synthesis and structure of polymorph B of zeolite Beta. Chemistry of Materials. 20(9):3218-3223. doi:10.1021/cm8002244S3218322320
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