2,819 research outputs found
Phylogeny and divergence of the pinnipeds (Carnivora: Mammalia) assessed using a multigene dataset
Abstract Background Phylogenetic comparative methods are often improved by complete phylogenies with meaningful branch lengths (e.g., divergence dates). This study presents a dated molecular supertree for all 34 world pinniped species derived from a weighted matrix representation with parsimony (MRP) supertree analysis of 50 gene trees, each determined under a maximum likelihood (ML) framework. Divergence times were determined by mapping the same sequence data (plus two additional genes) on to the supertree topology and calibrating the ML branch lengths against a range of fossil calibrations. We assessed the sensitivity of our supertree topology in two ways: 1) a second supertree with all mtDNA genes combined into a single source tree, and 2) likelihood-based supermatrix analyses. Divergence dates were also calculated using a Bayesian relaxed molecular clock with rate autocorrelation to test the sensitivity of our supertree results further. Results The resulting phylogenies all agreed broadly with recent molecular studies, in particular supporting the monophyly of Phocidae, Otariidae, and the two phocid subfamilies, as well as an Odobenidae + Otariidae sister relationship; areas of disagreement were limited to four more poorly supported regions. Neither the supertree nor supermatrix analyses supported the monophyly of the two traditional otariid subfamilies, supporting suggestions for the need for taxonomic revision in this group. Phocid relationships were similar to other recent studies and deeper branches were generally well-resolved. Halichoerus grypus was nested within a paraphyletic Pusa, although relationships within Phocina tend to be poorly supported. Divergence date estimates for the supertree were in good agreement with other studies and the available fossil record; however, the Bayesian relaxed molecular clock divergence date estimates were significantly older. Conclusion Our results join other recent studies and highlight the need for a re-evaluation of pinniped taxonomy, especially as regards the subfamilial classification of otariids and the generic nomenclature of Phocina. Even with the recent publication of new sequence data, the available genetic sequence information for several species, particularly those in Arctocephalus, remains very limited, especially for nuclear markers. However, resolution of parts of the tree will probably remain difficult, even with additional data, due to apparent rapid radiations. Our study addresses the lack of a recent pinniped phylogeny that includes all species and robust divergence dates for all nodes, and will therefore prove indispensable to comparative and macroevolutionary studies of this group of carnivores.</p
A higher-level MRP supertree of placental mammals
BACKGROUND: The higher-level phylogeny of placental mammals has long been a phylogenetic Gordian knot, with disagreement about both the precise contents of, and relationships between, the extant orders. A recent MRP supertree that favoured 'outdated' hypotheses (notably, monophyly of both Artiodactyla and Lipotyphla) has been heavily criticised for including low-quality and redundant data. We apply a stringent data selection protocol designed to minimise these problems to a much-expanded data set of morphological, molecular and combined source trees, to produce a supertree that includes every family of extant placental mammals. RESULTS: The supertree is well-resolved and supports both polyphyly of Lipotyphla and paraphyly of Artiodactyla with respect to Cetacea. The existence of four 'superorders' – Afrotheria, Xenarthra, Laurasiatheria and Euarchontoglires – is also supported. The topology is highly congruent with recent (molecular) phylogenetic analyses of placental mammals, but is considerably more comprehensive, being the first phylogeny to include all 113 extant families without making a priori assumptions of suprafamilial monophyly. Subsidiary analyses reveal that the data selection protocol played a key role in the major changes relative to a previously published higher-level supertree of placentals. CONCLUSION: The supertree should provide a useful framework for hypothesis testing in phylogenetic comparative biology, and supports the idea that biogeography has played a crucial role in the evolution of placental mammals. Our results demonstrate the importance of minimising poor and redundant data when constructing supertrees
Formation of gutingimycin: analytical investigation of trioxacarcin A-mediated alkylation of dsDNA
Formation and fragmentation of recognition complexes between trioxacarcin A and various DNA sequences were examined by temperature-dependent UV and CD spectroscopy, HPLC analysis, and ESI mass spectrometry with regard to reaction conditions, intermediates, products, mechanism, and sequence specificity. Cleavage of the trioxacarcin–DNA complexes provided the natural product gutingimycin by guanine abstraction. The resulting DNA with an abasic site was further cleaved into a DNA fragment with a furanyl unit at the 3′-end and an oligonucleotide with a phosphorylated 5′-end
Individualization as driving force of clustering phenomena in humans
One of the most intriguing dynamics in biological systems is the emergence of
clustering, the self-organization into separated agglomerations of individuals.
Several theories have been developed to explain clustering in, for instance,
multi-cellular organisms, ant colonies, bee hives, flocks of birds, schools of
fish, and animal herds. A persistent puzzle, however, is clustering of opinions
in human populations. The puzzle is particularly pressing if opinions vary
continuously, such as the degree to which citizens are in favor of or against a
vaccination program. Existing opinion formation models suggest that
"monoculture" is unavoidable in the long run, unless subsets of the population
are perfectly separated from each other. Yet, social diversity is a robust
empirical phenomenon, although perfect separation is hardly possible in an
increasingly connected world. Considering randomness did not overcome the
theoretical shortcomings so far. Small perturbations of individual opinions
trigger social influence cascades that inevitably lead to monoculture, while
larger noise disrupts opinion clusters and results in rampant individualism
without any social structure. Our solution of the puzzle builds on recent
empirical research, combining the integrative tendencies of social influence
with the disintegrative effects of individualization. A key element of the new
computational model is an adaptive kind of noise. We conduct simulation
experiments to demonstrate that with this kind of noise, a third phase besides
individualism and monoculture becomes possible, characterized by the formation
of metastable clusters with diversity between and consensus within clusters.
When clusters are small, individualization tendencies are too weak to prohibit
a fusion of clusters. When clusters grow too large, however, individualization
increases in strength, which promotes their splitting.Comment: 12 pages, 4 figure
A SELEX-Screened Aptamer of Human Hepatitis B Virus RNA Encapsidation Signal Suppresses Viral Replication
Background: The specific interaction between hepatitis B virus (HBV) polymerase (P protein) and the e RNA stem-loop on pregenomic (pg) RNA is crucial for viral replication. It triggers both pgRNA packaging and reverse transcription and thus represents an attractive antiviral target. RNA decoys mimicking e in P protein binding but not supporting replication might represent novel HBV inhibitors. However, because generation of recombinant enzymatically active HBV polymerase is notoriously difficult, such decoys have as yet not been identified. Methodology/Principal Findings: Here we used a SELEX approach, based on a new in vitro reconstitution system exploiting a recombinant truncated HBV P protein (miniP), to identify potential e decoys in two large e RNA pools with randomized upper stem. Selection of strongly P protein binding RNAs correlated with an unexpected strong enrichment of A residues. Two aptamers, S6 and S9, displayed particularly high affinity and specificity for miniP in vitro, yet did not support viral replication when part of a complete HBV genome. Introducing S9 RNA into transiently HBV producing HepG2 cells strongly suppressed pgRNA packaging and DNA synthesis, indicating the S9 RNA can indeed act as an e decoy that competitively inhibits P protein binding to the authentic e signal on pgRNA. Conclusions/Significance: This study demonstrates the first successful identification of human HBV e aptamers by an in vitro SELEX approach. Effective suppression of HBV replication by the S9 aptamer provides proof-of-principle for the abilit
Does trocar-guided tension-free vaginal mesh (Prolift™) repair provoke prolapse of the unaffected compartments?
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88857.pdf (publisher's version ) (Closed access)INTRODUCTION AND HYPOTHESIS: The objective of this study was to assess the effect of the tension-free vaginal mesh (Prolift) procedure on the non-treated and initially unaffected vaginal compartments. METHODS: This prospective observational cohort study involved 150 patients who underwent a Prolift procedure. Pelvic organ prolapse (POP) quantification and evaluation of prolapse symptoms with validated questionnaires was performed pre-operatively and 6 and 12 months postoperatively. Primary outcome was the rate of POP stage > or = II in the non-treated vaginal compartments. RESULTS: Twenty-three percent of all patients developed a de novo POP stage > or = II in the untreated compartment. This occurred in 46% and 25% of patients after an isolated anterior and isolated posterior Prolift, respectively. CONCLUSION: Tension-free vaginal mesh treatment of one vaginal compartment seems to provoke the development of vaginal prolapse in initially unaffected vaginal compartments, particularly after an isolated anterior Prolift procedure.1 maart 201
Accounting, Soci(et)al Risks, and Public Reason: Governmental Risk Discourses About the ILVA Steel Plant in Taranto (Italy)
The case of the ILVA steel plant in Taranto represents an example of con- trasting, incommensurable sustainability issues, explored in terms of “social” and “societal” risks (Asenova et al. in Managing the risks of public spending cuts in Scotland, 2013; Redistribution of social and societal risk: the impact on individuals, their networks and communities, 2015) [Asenova et al. (2015) refer to social risks as the risks of unemployment, and to societal risks as environmental and health risks.]. The case of ILVA has received significant attention for the great amount of dangerous pollutants spread in the environment, as well as the evidence of higher illness and mortality rates in the districts nearest to the plant. In July 2012, the Italian Judiciary halted activity in the steel plant. Four months after, the Italian Government declared the steel plant site as a “Strategic National Interest Site”, and allowed the company to restart its activity. Drawing on governmentality (Foucault in Questions of method, 1991), the paper aims to explore the role of accounting—here broadly intended as calculative practices (Miller in Soc Res 68:379–396, 2001)—in moulding ministerial discourse to support decisions when the governance of contrasting risks is needed to safeguard public interest. Supported by discourse analysis of governmental speech, the research shows that the Italian Government based its decision on various experts’ risk appraisals: accounting shaped governmental discourse by giving more visibility and relevance to “social” risks (i.e. unemployment, economic development, produc- tivity and competitiveness risks), while silencing “societal” ones (i.e. environmental and health risks). Focusing on a case of incommensurable contrasting issues, the findings contribute to show that accounting concurrently plays a significant role in government decisions legitimizing the business continuity through the creation of a specific risk discourse
Screening and diagnosing depression in women visiting GPs' drop in clinic in Primary Health Care
<p>Abstract</p> <p>Background</p> <p>Only half of all depressions are diagnosed in Primary Health Care (PHC). Depression can remain undetected for a long time and entail high costs for care and low quality of life for the individuals. Drop in clinic is a common form of organizing health care; however the visits are short and focus on solving the most urgent problems. The aim of this study was to investigate the prevalence and severity of depression among women visiting the GPs' drop in clinic and to identify possible clues for depression among women.</p> <p>Methods</p> <p>The two-stage screening method with "high risk feedback" was used. Beck's Depression Inventory (BDI) was used to screen 155 women visiting two GPs' drop in clinic. Women who screened positive (BDI score ≥10) were invited by the GP to a repeat visit. Major depression (MDD) was diagnosed according to DSM-IV criteria and the severity was assessed with Montgomery-Asberg Depression Rating Scale (MADRS). Women with BDI score <10 constituted a control group. Demographic characteristics were obtained by questionnaire. Chart notations were examined with regard to symptoms mentioned at the index visit and were categorized as somatic or mental.</p> <p>Results</p> <p>The two-stage method worked well with a low rate of withdrawals in the second step, when the GP invited the women to a repeat visit. The prevalence of depression was 22.4% (95% CI 15.6–29.2). The severity was mild in 43%, moderate in 53% and severe in 3%. The depressed women mentioned mental symptoms significantly more often (69%) than the controls (15%) and were to a higher extent sick-listed for a longer period than 14 days. Nearly one third of the depressed women did not mention mental symptoms. The majority of the women who screened as false positive for depression had crisis reactions and needed further care from health professionals in PHC. Referrals to a psychiatrist were few and revealed often psychiatric co-morbidity.</p> <p>Conclusion</p> <p>The prevalence of previously undiagnosed depression among women visiting GPs' drop in clinic was high. Clues for depression were identified in the depressed women's symptom presentation; they often mention mental symptoms when they visit the GP for somatic reasons e.g. respiratory infections. We suggest that GPs do selective screening for depression when women mention mental symptoms and offer to schedule a repeat visit for follow-up rather than just recommending that the patient return if the mental symptoms do not disappear.</p
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