1,612 research outputs found

    A call for the appropriate application of clinical pharmacological principles in the search for safe and efficacious COVID-19 (SARS-COV-2) treatments.

    Get PDF
    Syndrome Coronavirus 2 (SARS-CoV-2) has led to remarkable efforts by the scientific communities internationally to identify potential pharmacological treatments through the rapid initiation of clinical trials of novel and/or re-purposed regulatory authorityapproved therapies. We greatly welcome the significant global effort to safely expedite trials. However, we are concerned that many studies have not been of high quality to generate clinically meaningful data to enable effective translation to clinical practice. Identifying the “right” drug (or drug combinations) is only the first step. Applying core clinical pharmacology principles at all stages of research will help identify the right dose, the right patient, and the right treatment protocol. We hope that by setting out the principles outlined in this statement, efforts to find a safe and efficacious treatment for COVID-19 will have the best chance of success

    The holistic phase model of early adult crisis

    Get PDF
    The objective of the current study was to explore the structural, temporal and experiential manifestations of crisis episodes in early adulthood, using a holistic-systemic theoretical framework. Based on an analysis of 50 interviews with individuals about a crisis episode between the ages of 25 and 35, a holistic model was developed. The model comprises four phases: (1) Locked-in, (2) Separation/Time-out, (3) Exploration and (4) Rebuilding, which in turn have characteristic features at four levels—person-in-environment, identity, motivation and affect-cognition. A crisis starts out with a commitment at work or home that has been made but is no longer desired, and this is followed by an emotionally volatile period of change as that commitment is terminated. The positive trajectory of crisis involves movement through an exploratory period towards active rebuilding of a new commitment, but ‘fast-forward’ and ‘relapse’ loops can interrupt Phases 3 and 4 and make a positive resolution of the episode less likely. The model shows conceptual links with life stage theories of emerging adulthood and early adulthood, and it extends current understandings of the transitional developmental challenges that young adults encounter

    Role of chance and history during evolution in Chlamydomonas reinhardtii

    Get PDF
    The extent to which evolution is repeatable has important implications. If evolution is highly repeatable, the trajectories and outcomes of evolution in different lineages will always be the same. On the other hand, if evolution is not repeatable, then trajectories and outcomes will be diverse. Thus, the repeatability of evolution affects our understanding of the nature of biodiversity and can inform the extent to which evolutionary theory can be used to make predictions. The repeatability of evolution depends on the relative contribution of selection, chance, and history. To determine what factors affect the importance of chance and history during evolution, I propagated replicated populations of the unicellular green alga Chlamydomonas reinhardtii in controlled environments. I measured the change in fitness after a few hundred generations and determined how much variation had arisen among replicate populations and among populations with different histories. I applied a similar approach to study the importance of history in extinctions, and measured rates of extinction in populations with different histories. I found that evolution is much less repeatable in small than in large populations because history is more constraining and selection less efficient in small than in large populations. There is also a significant effect of sex and recombination on the repeatability of evolution at the fitness level, but this effect is highly dependent on the environment of selection. Sex can increase the importance of chance or history in some environments, but lower their importance in others, thereby leading to convergence or divergence depending on the environment. Thirdly, I found that the importance of history during evolution does not appear to come from the accumulation of past evolutionary selection pressures, but rather comes from only the most recent selection pressure as it determines genetic correlations for growth between different environments and the amount of genetic variance. Finally, I found that extinction risks are extremely high during continuous environmental deterioration, although a history of sexual reproduction and phenotypic plasticity play an important role in adaptation. By focusing not solely on the effect of treatments on mean trait values, but also on the variance that arises in our evolution experiments, we can gain a better understanding of the contribution that chance and history make to evolution. The repeatability of evolution can therefore inform us about the adaptive vs. stochastic nature of the diversity we see today, and about the specificity or generality of evolutionary outcomes

    Inductively guided circuits for ultracold dressed atoms

    Get PDF
    Recent progress in optics, atomic physics and material science has paved the way to study quantum effects in ultracold atomic alkali gases confined to non-trivial geometries. Multiply connected traps for cold atoms can be prepared by combining inhomogeneous distributions of DC and radio-frequency electromagnetic fields with optical fields that require complex systems for frequency control and stabilization. Here we propose a flexible and robust scheme that creates closed quasi-one-dimensional guides for ultracold atoms through the ‘dressing’ of hyperfine sublevels of the atomic ground state, where the dressing field is spatially modulated by inductive effects over a micro-engineered conducting loop. Remarkably, for commonly used atomic species (for example, 7Li and 87Rb), the guide operation relies entirely on controlling static and low-frequency fields in the regimes of radio-frequency and microwave frequencies. This novel trapping scheme can be implemented with current technology for micro-fabrication and electronic control

    The response of perennial and temporary headwater stream invertebrate communities to hydrological extremes

    Get PDF
    The headwaters of karst rivers experience considerable hydrological variability, including spates and streambed drying. Extreme summer flooding on the River Lathkill (Derbyshire, UK) provided the opportunity to examine the invertebrate community response to unseasonal spate flows, flow recession and, at temporary sites, streambed drying. Invertebrates were sampled at sites with differing flow permanence regimes during and after the spates. Following streambed drying at temporary sites, dewatered surface sediments were investigated as a refugium for aquatic invertebrates. Experimental rehydration of these dewatered sediments was conducted to promote development of desiccation-tolerant life stages. At perennial sites, spate flows reduced invertebrate abundance and diversity, whilst at temporary sites, flow reactivation facilitated rapid colonisation of the surface channel by a limited number of invertebrate taxa. Following streambed drying, 38 taxa were recorded from the dewatered and rehydrated sediments, with Oligochaeta being the most abundant taxon and Chironomidae (Diptera) the most diverse. Experimental rehydration of dewatered sediments revealed the presence of additional taxa, including Stenophylax sp. (Trichoptera: Limnephilidae) and Nemoura sp. (Plecoptera: Nemouridae). The influence of flow permanence on invertebrate community composition was apparent despite the aseasonal high-magnitude flood events

    The genetic contribution of single male immigrants to small, inbred populations: A laboratory study using drosophila melanogaster

    Get PDF
    This study examined the genetic contribution of single male immigrants to small, inbred laboratory populations of Drosophila melanogaster. Genetic contribution was assessed by measuring the relative frequency of immigrant marker alleles in the first and second generations after immigration, while controlling for any selection effects at the marker locus, and for the experience of male immigrants. When immigrants were outbred, the mean frequency of the immigrant allele was significantly higher than its initial frequency, in both the first and second generations after immigration. There was no significant change in allele frequency for populations receiving inbred immigrants. The increase in allele frequency for outbred immigrants was attributed to an initial outbred vigour fitness advantage of immigrant males over resident males experiencing inbreeding depression. Hybrid vigour of immigrant progeny and the rare-male effect did not have a statistically significant role in the fitness advantage of the immigrant allele. The results suggest that inbreeding may have a considerable impact on the contribution of immigrants to the genetic diversity of populations

    A systematic review of the effectiveness and cost-effectiveness of peer education and peer support in prisons.

    Get PDF
    BACKGROUND: Prisoners experience significantly worse health than the general population. This review examines the effectiveness and cost-effectiveness of peer interventions in prison settings. METHODS: A mixed methods systematic review of effectiveness and cost-effectiveness studies, including qualitative and quantitative synthesis was conducted. In addition to grey literature identified and searches of websites, nineteen electronic databases were searched from 1985 to 2012. Study selection criteria were: Population: Prisoners resident in adult prisons and children resident in Young Offender Institutions (YOIs). INTERVENTION: Peer-based interventions Comparators: Review questions 3 and 4 compared peer and professionally led approaches. OUTCOMES: Prisoner health or determinants of health; organisational/ process outcomes; views of prison populations. STUDY DESIGNS: Quantitative, qualitative and mixed method evaluations. RESULTS: Fifty-seven studies were included in the effectiveness review and one study in the cost-effectiveness review; most were of poor methodological quality. Evidence suggested that peer education interventions are effective at reducing risky behaviours, and that peer support services are acceptable within the prison environment and have a positive effect on recipients, practically or emotionally. Consistent evidence from many, predominantly qualitative, studies, suggested that being a peer deliverer was associated with positive effects. There was little evidence on cost-effectiveness of peer-based interventions. CONCLUSIONS: There is consistent evidence from a large number of studies that being a peer worker is associated with positive health; peer support services are also an acceptable source of help within the prison environment and can have a positive effect on recipients. Research into cost-effectiveness is sparse. SYSTEMATIC REVIEW REGISTRATION: PROSPERO ref: CRD42012002349
    • …
    corecore