536 research outputs found

    A Theory For The Asymmetry In The Auroral Ionization Density Profile For The Generation Of Auroral Infrasonic Waves

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    Thesis (Ph.D.) University of Alaska Fairbanks, 197

    Evidence for Horizontal Gene Transfer of Anaerobic Carbon Monoxide Dehydrogenases

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    Carbon monoxide (CO) is commonly known as a toxic gas, yet both cultivation studies and emerging genome sequences of bacteria and archaea establish that CO is a widely utilized microbial growth substrate. In this study, we determined the prevalence of anaerobic carbon monoxide dehydrogenases ([Ni,Fe]-CODHs) in currently available genomic sequence databases. Currently, 185 out of 2887, or 6% of sequenced bacterial and archaeal genomes possess at least one gene encoding [Ni,Fe]-CODH, the key enzyme for anaerobic CO utilization. Many genomes encode multiple copies of [Ni,Fe]-CODH genes whose functions and regulation are correlated with their associated gene clusters. The phylogenetic analysis of this extended protein family revealed six distinct clades; many clades consisted of [Ni,Fe]-CODHs that were encoded by microbes from disparate phylogenetic lineages, based on 16S rRNA sequences, and widely ranging physiology. To more clearly define if the branching patterns observed in the [Ni,Fe]-CODH trees are due to functional conservation vs. evolutionary lineage, the genomic context of the [Ni,Fe]-CODH gene clusters was examined, and superimposed on the phylogenetic trees. On the whole, there was a correlation between genomic contexts and the tree topology, but several functionally similar [Ni,Fe]-CODHs were found in different clades. In addition, some distantly related organisms have similar [Ni,Fe]-CODH genes. Thermosinus carboxydivorans was used to observe horizontal gene transfer (HGT) of [Ni,Fe]-CODH gene clusters by applying Kullback–Leibler divergence analysis methods. Divergent tetranucleotide frequency and codon usage showed that the gene cluster of T. carboxydivorans that encodes a [Ni,Fe]-CODH and an energy-converting hydrogenase is dissimilar to its whole genome but is similar to the genome of the phylogenetically distant Firmicute, Carboxydothermus hydrogenoformans. These results imply that T carboxydivorans acquired this gene cluster via HGT from a relative of C. hydrogenoformans

    101 Dothideomycetes genomes: A test case for predicting lifestyles and emergence of pathogens.

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    Dothideomycetes is the largest class of kingdom Fungi and comprises an incredible diversity of lifestyles, many of which have evolved multiple times. Plant pathogens represent a major ecological niche of the class Dothideomycetes and they are known to infect most major food crops and feedstocks for biomass and biofuel production. Studying the ecology and evolution of Dothideomycetes has significant implications for our fundamental understanding of fungal evolution, their adaptation to stress and host specificity, and practical implications with regard to the effects of climate change and on the food, feed, and livestock elements of the agro-economy. In this study, we present the first large-scale, whole-genome comparison of 101 Dothideomycetes introducing 55 newly sequenced species. The availability of whole-genome data produced a high-confidence phylogeny leading to reclassification of 25 organisms, provided a clearer picture of the relationships among the various families, and indicated that pathogenicity evolved multiple times within this class. We also identified gene family expansions and contractions across the Dothideomycetes phylogeny linked to ecological niches providing insights into genome evolution and adaptation across this group. Using machine-learning methods we classified fungi into lifestyle classes with >95 % accuracy and identified a small number of gene families that positively correlated with these distinctions. This can become a valuable tool for genome-based prediction of species lifestyle, especially for rarely seen and poorly studied species

    Uterine Artery Embolization in Patients with a Large Fibroid Burden: Long-Term Clinical and MR Follow-up

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    Uterine artery embolization (UAE) in patients with a large fibroid burden is controversial. Anecdotal reports describe serious complications and limited clinical results. We report the long-term clinical and magnetic resonance (MR) results in a large series of women with a dominant fibroid of >10 cm and/or an uterine volume of >700 cm3. Seventy-one consecutive patients (mean age, 42.5 years; median, 40 years; range, 25–52 years) with a large fibroid burden were treated by UAE between August 2000 and April 2005. Volume reduction and infarction rate of dominant fibroid and uterus were assessed by comparing the baseline and latest follow-up MRIs. Patients were clinically followed at various time intervals after UAE with standardized questionnaires. There were no serious complications of UAE. During a mean follow-up of 48 months (median, 59 months; range, 6–106 months), 10 of 71 patients (14%) had a hysterectomy. Mean volume reduction of the fibroid and uterus was 44 and 43%. Mean infarction rate of the fibroid and overall fibroid infarction rate was 86 and 87%. In the vast majority of patients there was a substantial improvement of symptoms. Clinical results were similar in patients with a dominant fibroid >10 cm and in patients with large uterine volumes by diffuse fibroid disease. In conclusion, our results indicate that the risk of serious complications after UAE in patients with a large fibroid burden is not increased. Moreover, clinical long-term results are as good as in other patients who are treated with UAE. Therefore, a large fibroid burden should not be considered a contraindication for UAE

    Improving the quality and content of midwives’ discussions with low-risk women about their options for place of birth: Co-production and evaluation of an intervention package

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    Objective: Women's planned place of birth is gaining increasing importance in the UK, however evidence suggests that there is variation in the content of community midwives’ discussions with low risk women about their place of birth options. The objective of this study was to develop an intervention to improve the quality and content of place of birth discussions between midwives and low-risk women and to evaluate this intervention in practice. Design: The study design comprised of three stages: (1) The first stage included focus groups with midwives to explore the barriers to carrying out place of birth discussions with women. (2) In the second stage, COM-B theory provided a structure for co-produced intervention development with midwives and women representatives; priority areas for change were agreed and the components of an intervention package to standardise the quality of these discussions were decided. (3) The third stage of the study adopted a mixed methods approach including questionnaires, focus groups and interviews with midwives to evaluate the implementation of the co-produced package in practice. Setting: A maternity NHS Trust in the West Midlands, UK. Participants: A total of 38 midwives took part in the first stage of the study. Intervention design (stage 2) included 58 midwives, and the evaluation (stage 3) involved 66 midwives. Four women were involved in the intervention design stage of the study in a Patient and Public Involvement role (not formally consented as participants). Findings: In the first study stage participants agreed that pragmatic, standardised information on the safety, intervention and transfer rates for each birth setting (obstetric unit, midwifery-led unit, home) was required. In the second stage of the study, co-production between researchers, women and midwives resulted in an intervention package designed to support the implementation of these changes and included an update session for midwives, a script, a leaflet, and ongoing support through a named lead midwife and regular team meetings. Evaluation of this package in practice revealed that midwives’ knowledge and confidence regarding place of birth substantially improved after the initial update session and was sustained three months post-implementation. Midwives viewed the resources as useful in prompting discussions and aiding communication about place of birth options. Key conclusions and implications for practice: Co-production enabled development of a pragmatic intervention to improve the quality of midwives’ place of birth discussions with low-risk women, supported by COM-B theory. These findings highlight the importance of co-production in intervention development and suggest that the place of birth package could be used to improve place of birth discussions to facilitate informed choice at other Trusts across the UK

    Utopianism and social change: materialism, conflict and pluralism

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    This article discusses criticisms that utopia and utopianism undermine social change. It outlines two types of utopia, future and current. It argues against claims that utopianism is idealist and steps aside from material and conflictual dimensions of society and so undermines change, proposing that utopias are material and conflictual and contribute to change. Against liberal and pluralist criticisms that utopianism is end-ist and totalitarian and terminates diversity and change it argues that utopianism can encompass liberal and pluralist dimensions and be dynamic rather than static. It is proposed that criticisms create false conflations and dichotomies. Critical perspectives, rather than being rejected, are answered on their own terms. Utopianism, it is argued, is part of change, materially, now and in the future

    User-centered virtual environment design for virtual rehabilitation

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    <p>Abstract</p> <p>Background</p> <p>As physical and cognitive rehabilitation protocols utilizing virtual environments transition from single applications to comprehensive rehabilitation programs there is a need for a new design cycle methodology. Current human-computer interaction designs focus on usability without benchmarking technology within a user-in-the-loop design cycle. The field of virtual rehabilitation is unique in that determining the efficacy of this genre of computer-aided therapies requires prior knowledge of technology issues that may confound patient outcome measures. Benchmarking the technology (e.g., displays or data gloves) using healthy controls may provide a means of characterizing the "normal" performance range of the virtual rehabilitation system. This standard not only allows therapists to select appropriate technology for use with their patient populations, it also allows them to account for technology limitations when assessing treatment efficacy.</p> <p>Methods</p> <p>An overview of the proposed user-centered design cycle is given. Comparisons of two optical see-through head-worn displays provide an example of benchmarking techniques. Benchmarks were obtained using a novel vision test capable of measuring a user's stereoacuity while wearing different types of head-worn displays. Results from healthy participants who performed both virtual and real-world versions of the stereoacuity test are discussed with respect to virtual rehabilitation design.</p> <p>Results</p> <p>The user-centered design cycle argues for benchmarking to precede virtual environment construction, especially for therapeutic applications. Results from real-world testing illustrate the general limitations in stereoacuity attained when viewing content using a head-worn display. Further, the stereoacuity vision benchmark test highlights differences in user performance when utilizing a similar style of head-worn display. These results support the need for including benchmarks as a means of better understanding user outcomes, especially for patient populations.</p> <p>Conclusions</p> <p>The stereoacuity testing confirms that without benchmarking in the design cycle poor user performance could be misconstrued as resulting from the participant's injury state. Thus, a user-centered design cycle that includes benchmarking for the different sensory modalities is recommended for accurate interpretation of the efficacy of the virtual environment based rehabilitation programs.</p

    Lithium side effects and toxicity: prevalence and management strategies

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    Despite its virtually universal acceptance as the gold standard in treating bipolar disorder, prescription rates for lithium have been decreasing recently. Although this observation is multifactorial, one obvious potential contributor is the side effect and toxicity burden associated with lithium. Additionally, side effect concerns assuredly play some role in lithium nonadherence. This paper summarizes the knowledge base on side effects and toxicity and suggests optimal management of these problems. Thirst and excessive urination, nausea and diarrhea and tremor are rather common side effects that are typically no more than annoying even though they are rather prevalent. A simple set of management strategies that involve the timing of the lithium dose, minimizing lithium levels within the therapeutic range and, in some situations, the prescription of side effect antidotes will minimize the side effect burden for patients. In contrast, weight gain and cognitive impairment from lithium tend to be more distressing to patients, more difficult to manage and more likely to be associated with lithium nonadherence. Lithium has adverse effects on the kidneys, thyroid gland and parathyroid glands, necessitating monitoring of these organ functions through periodic blood tests. In most cases, lithium-associated renal effects are relatively mild. A small but measurable percentage of lithium-treated patients will show progressive renal impairment. Infrequently, lithium will need to be discontinued because of the progressive renal insufficiency. Lithium-induced hypothyroidism is relatively common but easily diagnosed and treated. Hyperparathyroidism from lithium is a relatively more recently recognized phenomenon
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