908 research outputs found

    Quantifying abundance and distribution of native and invasive oysters in an urbanised estuary

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    Human activities have modified the chemical, physical and biological attributes of many of the world’s estuaries. Natural foreshores have been replaced by artificial habitats and non-indigenous species have been introduced by shipping, aquaculture, and as ornamental pets. In south east Australia, the native Sydney rock oyster Saccostrea glomerata is threatened by pollution, disease and competition from the invasive Pacific oyster Crassostrea gigas. This study assessed the abundance (as number m-2), size, and distribution of both invasive and native oyster species at 32 sites in the heavily urbanised Port Jackson Estuary, Australia. We tested the hypotheses that there would be: (1) a difference in the proportion of C. gigas and S. glomerata among locations; (2) a greater proportion of C. gigas on artificial compared to natural substrates; (3) a greater numbers of all oysters, with differing size characteristics, on artificial compared to natural substrates; and (4) that the abundance and size of all oysters would vary among locations along an environmental gradient. Environmental variables included distance from the estuary mouth and salinity. We found the abundance and size of all oysters differed among locations; smaller oysters occurred at greater abundances near the mouth of the estuary. Abundance was also higher on artificial, than on natural substrate. Habitat type, however, had no effect on which species of oyster was present. In contrast, distance from the estuary mouth strongly influenced the relative proportion of the two species. The invasive C. gigas comprised 16% of the oysters sampled, and up to 85% at some of the upper estuary sites. As predicted, C. gigas was more abundant at locations in the bay ends and upper channel of the estuary; it was also larger in size than the native S. glomerata. This is the first assessment of oyster distribution in Port Jackson and provides a solid base for monitoring changes in the estuarine distribution of a globally invasive pest

    Association Between Handover of Anesthesiology Care and 1-Year Mortality Among Adults Undergoing Cardiac Surgery

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    Importance Handovers of anesthesia care from one anesthesiologist to another is an important intraoperative event. Despite its association with adverse events after noncardiac surgery, its impact in the context of cardiac surgery remains unclear. Objective To compare the outcomes of patients who were exposed to anesthesia handover vs those who were unexposed to anesthesia handover during cardiac surgery. Design, Setting, and Participants This retrospective cohort study in Ontario, Canada, included Ontario residents who were 18 years or older and had undergone coronary artery bypass grafting or aortic, mitral, tricuspid valve, or thoracic aorta surgical procedures between 2008 and 2019. Exclusion criteria were non-Ontario residency status and other concomitant procedures. Statistical analysis was conducted from April 2021 to June 2021, and data collection occurred between November 2020 to January 2021. Exposures Complete handover of anesthesia care, where the case is completed by the replacement anesthesiologist. Main Outcomes and Measures The coprimary outcomes were mortality within 30 days and 1 year after surgery. Secondary outcomes were patient-defined adverse cardiac and noncardiac events (PACE), intensive care unit (ICU), and hospital lengths of stay (LOS). Inverse probability of treatment weighting based on the propensity score was used to estimate adjusted effect measures. Mortality was assessed using a Cox proportional hazard model, PACE using a cause-specific hazard model with death as a competing risk, and LOS using Poisson regression. Results Of the 102 156 patients in the cohort, 25 207 (24.7%) were women; the mean (SD) age was 66.4 (10.8) years; and 72 843 of surgical procedures (71.3%) were performed in teaching hospitals. Handover occurred in 1926 patients (1.9%) and was associated with higher risks of 30-day mortality (hazard ratio [HR], 1.89; 95% CI, 1.41-2.54) and 1-year mortality (HR, 1.66; 95% CI, 1.31-2.12), as well as longer ICU (risk ratio [RR], 1.43; 95% CI, 1.22-1.68) and hospital (RR, 1.17; 95% CI, 1.06-1.28) LOS. There was no statistically significant association between handover and PACE (30 days: HR 1.09; 95% CI, 0.79-1.49; 1 year: HR 0.89; 95% CI, 0.70-1.13). Conclusions and Relevance Handover of anesthesia care during cardiac surgical procedures was associated with higher 30-day and 1-year mortality rates and increased health care resource use. Further research is needed to evaluate and systematically improve the handover process qualitatively

    Microbiomes of the Sydney Rock Oyster are acquired through both vertical and horizontal transmission

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    Abstract Background The term holobiont is widely accepted to describe animal hosts and their associated microorganisms. The genomes of all that the holobiont encompasses, are termed the hologenome and it has been proposed as a unit of selection in evolution. To demonstrate that natural selection acts on the hologenome, a significant portion of the associated microbial genomes should be transferred between generations. Using the Sydney Rock Oyster (Saccostrea glomerata) as a model, we tested if the microbes of this broadcast spawning species could be passed down to the next generation by conducting single parent crosses and tracking the microbiome from parent to offspring and throughout early larval stages using 16S rRNA gene amplicon sequencing. From each cross, we sampled adult tissues (mantle, gill, stomach, gonad, eggs or sperm), larvae (D-veliger, umbo, eyed pediveliger, and spat), and the surrounding environment (water and algae feed) for microbial community analysis. Results We found that each larval stage has a distinct microbiome that is partially influenced by their parental microbiome, particularly the maternal egg microbiome. We also demonstrate the presence of core microbes that are consistent across all families, persist throughout early life stages (from eggs to spat), and are not detected in the microbiomes of the surrounding environment. In addition to the core microbiomes that span all life cycle stages, there is also evidence of environmentally acquired microbial communities, with earlier larval stages (D-veliger and umbo), more influenced by seawater microbiomes, and later larval stages (eyed pediveliger and spat) dominated by microbial members that are specific to oysters and not detected in the surrounding environment. Conclusion Our study characterized the succession of oyster larvae microbiomes from gametes to spat and tracked selected members that persisted across multiple life stages. Overall our findings suggest that both horizontal and vertical transmission routes are possible for the complex microbial communities associated with a broadcast spawning marine invertebrate. We demonstrate that not all members of oyster-associated microbiomes are governed by the same ecological dynamics, which is critical for determining what constitutes a hologenome. </jats:sec

    The Ontology of Intentional Agency in Light of Neurobiological Determinism: Philosophy Meets Folk Psychology

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    The moot point of the Western philosophical rhetoric about free will consists in examining whether the claim of authorship to intentional, deliberative actions fits into or is undermined by a one-way causal framework of determinism. Philosophers who think that reconciliation between the two is possible are known as metaphysical compatibilists. However, there are philosophers populating the other end of the spectrum, known as the metaphysical libertarians, who maintain that claim to intentional agency cannot be sustained unless it is assumed that indeterministic causal processes pervade the action-implementation apparatus employed by the agent. The metaphysical libertarians differ among themselves on the question of whether the indeterministic causal relation exists between the series of intentional states and processes, both conscious and unconscious, and the action, making claim for what has come to be known as the event-causal view, or between the agent and the action, arguing that a sort of agent causation is at work. In this paper, I have tried to propose that certain features of both event-causal and agent-causal libertarian views need to be combined in order to provide a more defendable compatibilist account accommodating deliberative actions with deterministic causation. The ‘‘agent-executed-eventcausal libertarianism’’, the account of agency I have tried to develop here, integrates certain plausible features of the two competing accounts of libertarianism turning them into a consistent whole. I hope to show in the process that the integration of these two variants of libertarianism does not challenge what some accounts of metaphysical compatibilism propose—that there exists a broader deterministic relation between the web of mental and extra-mental components constituting the agent’s dispositional system—the agent’s beliefs, desires, short-term and long-term goals based on them, the acquired social, cultural and religious beliefs, the general and immediate and situational environment in which the agent is placed, etc. on the one hand and the decisions she makes over her lifetime on the basis of these factors. While in the ‘‘Introduction’’ the philosophically assumed anomaly between deterministic causation and the intentional act of deciding has been briefly surveyed, the second section is devoted to the task of bridging the gap between compatibilism and libertarianism. The next section of the paper turns to an analysis of folk-psychological concepts and intuitions about the effects of neurochemical processes and prior mental events on the freedom of making choices. How philosophical insights can be beneficially informed by taking into consideration folk-psychological intuitions has also been discussed, thus setting up the background for such analysis. It has been suggested in the end that support for the proposed theory of intentional agency can be found in the folk-psychological intuitions, when they are taken in the right perspective

    Osteological and Soft-Tissue Evidence for Pneumatization in the Cervical Column of the Ostrich (Struthio camelus) and Observations on the Vertebral Columns of Non-Volant, Semi-Volant and Semi-Aquatic Birds

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    © 2015 Apostolaki et al. This is an open access article distributed under the terms of the Creative Commons Attribution License [4.0], which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

    An Intact Kidney Slice Model to Investigate Vasa Recta Properties and Function in situ

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    Background: Medullary blood flow is via vasa recta capillaries, which possess contractile pericytes. In vitro studies using isolated descending vasa recta show that pericytes can constrict/dilate descending vasa recta when vasoactive substances are present. We describe a live kidney slice model in which pericyte-mediated vasa recta constriction/dilation can be visualized in situ. Methods: Confocal microscopy was used to image calcein, propidium iodide and Hoechst labelling in ‘live’ kidney slices, to determine tubular and vascular cell viability and morphology. DIC video-imaging of live kidney slices was employed to investigate pericyte-mediated real-time changes in vasa recta diameter. Results: Pericytes were identified on vasa recta and their morphology and density were characterized in the medulla. Pericyte-mediated changes in vasa recta diameter (10–30%) were evoked in response to bath application of vasoactive agents (norepinephrine, endothelin-1, angiotensin-II and prostaglandin E2) or by manipulating endogenous vasoactive signalling pathways (using tyramine, L-NAME, a cyclo-oxygenase (COX-1) inhibitor indomethacin, and ATP release). Conclusions: The live kidney slice model is a valid complementary technique for investigating vasa recta function in situ and the role of pericytes as regulators of vasa recta diameter. This technique may also be useful in exploring the role of tubulovascular crosstalk in regulation of medullary blood flow

    Cloning and heterologous expression of bovine pyroglutamyl peptidase type-1 in Escherichia coli : purification , biochemical and kinetic characterisation

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    We describe the cloning, expression and purification of the bovine XM866409 form of pyroglutamyl-aminopeptidase I. The amino acid sequence, deduced from the nucleotide sequence, revealed that it consists of 209 amino acid residues and showed to have 98% homology with the human AJ278828 form of the enzyme. Three amino acid residues at positions 81, 205 and 208 were found to vary among the two sequences. The bovine enzyme was expressed in XL10-gold Esherichia coli cells. Immobilizied Ni-ion affinity chromatography was used to purify the expressed protein resulting in a yield of 3.3mg of PAP1 per litre culture. The purified enzyme had a specific activity of 1700 units/ml. SDS-PAGE produced a single band for bovine PAP1 with a molecular weight of ~23-24 kDa which is in good agreement with previously reported data on PAP1. Kinetic constants Km and Kcat were 59μΜ and 3.5s-1, respectively. It possessed an optimum pH between 9-9.5, a temperature of 37°C and showed an absolute requirement for a thiol-reducing agent (10mM DTT). EDTA didn’t prove to have an effect on enzyme activity. Competitive inhibition was seen with pyroglutamyl peptides pGlu-His-Pro-NH2 (TRH; Ki= 44.1 uM), pGlu-Ala- OH (Ki=141 uM) and pGlu-Val-OH (Ki=652.17)

    Future-oriented constructs and their role in suicidal ideation and enactment

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    Despite the heavy focus upon risk factors for suicide, the presence or absence of protective factors are also instrumental in individuals’ vulnerability for developing suicidal ideation and behaviours. Future oriented constructs, including future thinking, future orientation, hope and optimism have been associated with suicidal ideation and behaviour; individuals who are less able to generate positive thoughts about the future, and those are less hopeful and optimistic are more likely to think about or engage in suicidal behaviours. The content and expectations of future thoughts as achievable also play a key role in their protective capacity. Within this chapter we discuss the relationships between future orientated constructs and suicidal ideation and behaviour, as well as potential mediators of these relationships, within the context of the new generation of ideation-to-action frameworks of suicidal behaviour. We also highlight challenges and opportunities for future research and intervention development for suicidal thoughts and behaviours using future oriented constructs

    The impact of situational context on software process: a case study of a very small-sized company in the online advertising domain

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    A primary concern of software development is selecting a suitable methodology to implement a software project. However, this selection is affected by many factors, with evidence suggesting that a specific set of factors defines a specific situational context for a project. This situational context leads to a project-specific software process. In this paper, we report on our analysis of a very small-sized company’s current software process based on a reference framework that identifies the factors of a situational context. The outcome of our case study confirms the earlier findings that a software process is highly dependent on situational factors. The company has a suitable situational context (such as very small-sized, experienced, skilled, cohesive team with low turnover) to apply agile practices and its software process is more close to an agile rather than plan-driven approach. Moreover, the company is continuously adopting its software process to the situational factors changing from project to project and over time
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