375 research outputs found

    Massively distributed authorship of academic papers

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    Wiki-like or crowdsourcing models of collaboration can provide a number of benefits to academic work. These techniques may engage expertise from different disciplines, and potentially increase productivity. This paper presents a model of massively distributed collaborative authorship of academic papers. This model, developed by a collective of thirty authors, identifies key tools and techniques that would be necessary or useful to the writing process. The process of collaboratively writing this paper was used to discover, negotiate, and document issues in massively authored scholarship. Our work provides the first extensive discussion of the experiential aspects of large-scale collaborative researc

    Anaerobic digestion and Co-digestion of oleaginous Microalgae residues for biogas production

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    Microalgae have been suggested as one of the most promising feedstock for the production of bioenergy and biofuels, including biodiesel and aviation fuels, because of the high oil content of selected species. In the context of biofuel production from microalgae, anaerobic digestion of microalgal biomass residues after oil extraction has the potential to make the process more sustainable and increase the energy efficiency. The main goal of this study was to assess microalgae residues as substrates for anaerobic digestion and investigate their potential for biomethane production. Biochemical Methane Potential (BMP) tests were carried out on a microalgal species, Nannochloropsis gaditana, selected for its high oil content and fast growth rate. The methane potentials observed for the microalgae residue after lipid extraction were higher than those recorded for the raw microalgae samples. Co-digestion with cellulose did not clearly enhance the anaerobic digestion performances

    Biotransformation of water lettuce (Pistia stratiotes) to biohydrogen by Rhodopseudomonas palustris

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    Aims: Aim of the paper was to assess the feasibility of producing hydrogen as a biofuel by photofermentation of fermented water lettuce (Pistia stratiotes L.) waste biomass, after a nitrogen-stripping treatment. Methods and Results: A natural (42OL) and an engineered strain (CGA676, with low-ammonium sensitivity) of Rhodopseudomonas palustris were used for producing hydrogen. The stripping procedure was highly effective for ammonium removal, with an acceptable selectivity (91% of ammonium was removed; only 14% of total organic acids were lost). Both strains were able to produce hydrogen only in the nitrogen-stripped substrate. The natural strain R. palustris 42OL showed a higher Biochemical Hydrogen Potential (1224 ml l−1 vs 720 ml l−1; 50·0 mol m−3 vs 29·4 mol m−3), but at a lower rate (5·6 ml l−1 h−1 vs 7·3 ml l−1 h−1; 0·23 mol m−3 h−1 vs 0·29 mol m−3 h−1) than strain CGA676. Conclusions: Water lettuce waste biomass can be used for biofuel production, after hydrolization, fermentation and nitrogen stripping. Significance and Impact of the Study: The investigation on novel, low cost and sustainable biomasses as feedstocks for biofuel production is a priority. Aquatic plants do not compete for arable land. Moreover, water lettuce is a floating and invasive weed, thus its biomass must be harvested when detrimental, and can now be biotransformed in clean hydrogen

    Venom insulins of cone snails diversify rapidly and track prey taxa

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    A specialized insulin was recently found in the venom of a fish-hunting cone snail, Conus geographus. Here we show that many worm-hunting and snail-hunting cones also express venom insulins, and that this novel gene family has diversified explosively. Cone snails express a highly conserved insulin in their nerve ring; presumably this conventional signaling insulin is finely tuned to the Conus insulin receptor, which also evolves very slowly. By contrast, the venom insulins diverge rapidly, apparently in response to biotic interactions with prey and also possibly the cones’ own predators and competitors. Thus, the inwardly directed signaling insulins appear to experience predominantly purifying sele\ction to target an internal receptor that seldom changes, while the outwardly directed venom insulins frequently experience directional selection to target heterospecific insulin receptors in a changing mix of prey, predators and competitors. Prey insulin receptors may often be constrained in ways that prevent their evolutionary escape from targeted venom insulins, if amino-acid substitutions that result in escape also degrade the receptor’s signaling functions

    Applying Research Ethics Guidelines: The View from a Sub-Saharan Research Ethics Committee

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    Considerable variation has been demonstrated in applying regulations across research ethics committees (RECs) in the U.S., U.K., and European nations. With the rise of international research collaborations, RECs in developing countries apply a variety of international regulations. We conducted a qualitative descriptive pilot study with members of the national REC in Malawi to determine criteria they use to review research, and their views on international collaborations. Qualitative content analysis demonstrated that international guidelines are interpreted in light of local African conditions such that emphasis is placed on examining benefit to the community and ensuring the informed consent process translates concepts in locally-meaningful ways. Members suggest that RECs often must comply with regulations that do not fit local conditions. Recommendations are provided for improving such international collaborations

    Differences between international recommendations on breastfeeding in the presence of HIV and the attitudes and counselling messages of health workers in Lilongwe, Malawi

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    BACKGROUND: To prevent postnatal transmission of HIV in settings where safe alternatives to breastfeeding are unavailable, the World Health Organization (WHO) recommends exclusive breastfeeding followed by early, rapid cessation of breastfeeding. Only limited data are available on the attitudes of health workers toward this recommendation and the impact of these attitudes on infant feeding counselling messages given to mothers. METHODS: As part of the Breastfeeding, Antiretroviral, and Nutrition (BAN) clinical trial, we carried out an in-depth qualitative study of the attitudes, beliefs, and counselling messages of 19 health workers in Lilongwe, Malawi. RESULTS: Although none of the workers had received formal training, several reported having counseled HIV-positive mothers about infant feeding. Health workers with counselling experience believed that HIV-infected mothers should breastfeed exclusively, rather than infant formula feed, citing poverty as the primary reason. Because of high levels of malnutrition, all the workers had concerns about early cessation of breastfeeding. CONCLUSION: Important differences were observed between the WHO recommendations and the attitudes and practices of the health workers. Understanding these differences is important for designing effective interventions

    Comparative genomic and phylogenetic approaches to characterize the role of genetic recombination in mycobacterial evolution

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    The genus Mycobacterium encompasses over one hundred named species of environmental and pathogenic organisms, including the causative agents of devastating human diseases such as tuberculosis and leprosy. The success of these human pathogens is due in part to their ability to rapidly adapt to their changing environment and host. Recombination is the fastest way for bacterial genomes to acquire genetic material, but conflicting results about the extent of recombination in the genus Mycobacterium have been reported. We examined a data set comprising 18 distinct strains from 13 named species for evidence of recombination. Genomic regions common to all strains (accounting for 10% to 22% of the full genomes of all examined species) were aligned and concatenated in the chromosomal order of one mycobacterial reference species. The concatenated sequence was screened for evidence of recombination using a variety of statistical methods, with each proposed event evaluated by comparing maximum-likelihood phylogenies of the recombinant section with the non-recombinant portion of the dataset. Incongruent phylogenies were identified by comparing the site-wise log-likelihoods of each tree using multiple tests. We also used a phylogenomic approach to identify genes that may have been acquired through horizontal transfer from non-mycobacterial sources. The most frequent associated lineages (and potential gene transfer partners) in the Mycobacterium lineage-restricted gene trees are other members of suborder Corynebacterinae, but more-distant partners were identified as well. In two examined cases of potentially frequent and habitat-directed transfer ( M. abscessus to Segniliparus and M. smegmatis to Streptomyces ), observed sequence distances were small and consistent with a hypothesis of transfer, while in a third case ( M. vanbaalenii to Streptomyces ) distances were larger. The analyses described here indicate that whereas evidence of recombination in core regions within the genus is relatively sparse, the acquisition of genes from non-mycobacterial lineages is a significant feature of mycobacterial evolution

    Endocrine dysfunction in patients operated on for non-pituitary intracranial tumors

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    Objective: Hypopituitarism frequently follows pituitary neurosurgery (NS) and/or irradiation. However, the frequency of hypothalamic–pituitary dysfunction after NS of non-pituitary intracranial tumors is unclear. The aim of this study was to assess the presence of endocrine alterations in patients operated on for intracranial tumors. Design: This is a retrospective study. Methods: We studied 68 consecutive adult patients (28 female, 40 male, age 45.0 ± 1.8 years; body mass index (BMI): 26.5 ± 0.6) with intracranial tumors who underwent NS only (n = 17) or in combination with radiotherapy (RT) and/or chemotherapy (CT) (n = 51). In all subjects, basal endocrine parameters and the GH response to GHRH + arginine test (using BMI-dependent cut offs) were evaluated. Results: In 20.6% of the patients, peripheral endocrinopathy related to CT and/or RT was present. Hypopituitarism was found in 38.2% of the patients. Total pituitary hormone, multiple pituitary hormone, and isolated pituitary hormone deficits were present in 16.2, 5.8, and 16.2% respectively. The most common pituitary deficits were, in decreasing order: LH/FSH 29.4%, GH 27.9%, ACTH 19.1%, TSH 17.7%, and diabetes insipidus 4.4%. Hyperprolactinemia was present in 13.2%. The prevalence of hypopituitarism was higher in patients who underwent NS only and with tumors located closely to the sella turcica, but a substantial proportion of patients with tumors not directly neighboring the sella also showed hypopituitarism. Conclusions: Hypopituitarism frequently occurs after NS for intracranial tumors. Also, exposure of these patients to CT and/or RT is frequently associated with peripheral endocrinopathies. Thus, endocrine evaluation and follow-up of patients treated for intracranial tumors should be performed on a regular basis

    Improving Participant Understanding of Informed Consent in an HIV-Prevention Clinical Trial: A Comparison of Methods

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    Empirical research on informed consent has shown that study participants often do not fully understand consent information. This study assessed participant understanding of three mock consent approaches describing an HIV-prevention clinical trial in Lilongwe, Malawi prior to trial implementation. Pregnant women (n = 297) were systematically selected from antenatal-care waiting lines and sequentially allocated to receive an enhanced standard consent form (group 1), a context-specific consent form (group 2), or context-specific counseling cards (group 3). Understanding of research concepts and study procedures was assessed immediately postintervention and at 1-week follow-up. At postintervention, participants in groups 2 and 3 understood more about research concepts and study procedures compared with group 1. Group 3 participants also understood more about study procedures compared with group 2. At follow-up, participants in groups 2 and 3 continued to understand more about research concepts and study procedures. Context-specific approaches improved understanding of consent information in this study

    Involving communities in the design of clinical trial protocols: The BAN Study in Lilongwe, Malawi

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    To learn the attitudes and concerns of the local community on participating in research, infant feeding practices, and maternal nutrition in order to inform the design of a clinical trial in Lilongwe, Malawi on the safety and efficacy of antiretroviral and nutrition interventions to reduce postnatal transmission of HIV
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