910 research outputs found

    A 2-set-up Routley-Meyer Semantics for the 4-valued Relevant Logic E4

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    The logic BN4 can be considered as the 4-valued logic of the relevant conditional and the logic E4, as the 4-valued logic of (relevant) entailment. The aim of this paper is to endow E4 with a 2-set-up Routley-Meyer semantics. It is proved that E4 is strongly sound and complete w.r.t. this semantics

    Selecting the Class of All 3-Valued Implicative Expansions of Kleene's Strong Logic Containing Routley and Meyer's Logic B

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    We define all implicative expansions of Kleene's strong 3-valued matrix (with both only one and two designated values) verifying Routley and Meyer's basic logic B. Then, the logics determined by each one of these implicative expansions are axiomatized by using a Belnap-Dunn "two-valued" semantics. This semantics is "overdetermined" in the case of two designated values, and "underdetermined" when there is only one.SIMinisterio de Economía, Industria y Competitivida

    Evolution of nonstop, no-go and nonsense-mediated mRNA decay and their termination factor-derived components

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    <p>Abstract</p> <p>Background</p> <p>Members of the eukaryote/archaea specific eRF1 and eRF3 protein families have central roles in translation termination. They are also central to various mRNA surveillance mechanisms, together with the eRF1 paralogue Dom34p and the eRF3 paralogues Hbs1p and Ski7p. We have examined the evolution of eRF1 and eRF3 families using sequence similarity searching, multiple sequence alignment and phylogenetic analysis.</p> <p>Results</p> <p>Extensive BLAST searches confirm that Hbs1p and eRF3 are limited to eukaryotes, while Dom34p and eRF1 (a/eRF1) are universal in eukaryotes and archaea. Ski7p appears to be restricted to a subset of <it>Saccharomyces </it>species. Alignments show that Dom34p does not possess the characteristic class-1 RF minidomains GGQ, NIKS and YXCXXXF, in line with recent crystallographic analysis of Dom34p. Phylogenetic trees of the protein families allow us to reconstruct the evolution of mRNA surveillance mechanisms mediated by these proteins in eukaryotes and archaea.</p> <p>Conclusion</p> <p>We propose that the last common ancestor of eukaryotes and archaea possessed Dom34p-mediated no-go decay (NGD). This ancestral Dom34p may or may not have required a trGTPase, mostly like a/eEF1A, for its delivery to the ribosome. At an early stage in eukaryotic evolution, eEF1A was duplicated, giving rise to eRF3, which was recruited for translation termination, interacting with eRF1. eRF3 evolved nonsense-mediated decay (NMD) activity either before or after it was again duplicated, giving rise to Hbs1p, which we propose was recruited to assist eDom34p in eukaryotic NGD. Finally, a third duplication within ascomycete yeast gave rise to Ski7p, which may have become specialised for a subset of existing Hbs1p functions in non-stop decay (NSD). We suggest Ski7p-mediated NSD may be a specialised mechanism for counteracting the effects of increased stop codon read-through caused by prion-domain [PSI+] mediated eRF3 precipitation.</p

    Relational Semantics for the Paraconsistent and Paracomplete 4-valued Logic PŁ4

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    The paraconsistent and paracomplete 4-valued logic PŁ4 is originally interpreted with a two-valued Belnap-Dunn semantics. In the present paper, PŁ4 is endowed with both a ternary Routley-Meyer semantics and a binary Routley semantics together with their respective restriction to the 2 set-up cases

    The influence of personal communities in understanding avoidable emergency department attendance: qualitative study

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    Background: Use of emergency department (ED) care globally seems to be increasing at a faster rate than population growth (Baker, House of Commons Library. Accident and Emergency Statistics, Demand, Performance, 2017). In the UK there has been a reported 16% rise in emergency admissions over the past 5 years. Estimates that between 11 and 40% of ED attendances are non-urgent, with 11% of patients being discharged from the ED without treatment (NHS Digital 2017), and a further 44% require no follow-up treatment (NHS Digital, Hospital Accident and Emergency Activity 2016-17, 2019) is cited as evidence that these patients did not require this level of care. The solution to not using the most appropriate point in the system has traditionally been seen as a knowledge problem, requiring, improved sign-posting and information to enable people to self-manage or use health care management for minor ailments. However research about help-seeking behaviour suggests that the problem may not be an informational one. A considerable literature points to help seeking as a social process influenced by a range of contingencies and contextual factors including the way in which lay people influence health care utilisation (Giebel et al. BMJ Open 9:1, 2019). Personal communities comprise a variety of active and significant social ties which have potential to influence individual capacity to seek help. Here we extend and unpack further influencing decisions about seeking formal health care with reference to how they are shaped and informed by and within personal social networks. Methods: We undertook a personal network mapping and qualitative interview-based study to look at, problematize and understand attendance for non-urgent problems. We used network analysis and methods to map and characterise the personal communities of people seeking help from ED for minor ailments and semi-structured interviews with 40 people attending a single ED and associated GP hub providing equivalent care. Interviews were built around an ego network mapping activity and a topic guide structured to explore attender's narratives about why they had visited the ED. This ego network activity uses a diagram consisting of three concentric circles (Fiori et al. J Gerontol B-Psychol 62: 322-30, 2007), representing closest social network members (in the centre) and those at further distance. Participants were initially presented with one of these diagrams and asked to write names of people or resources that had played a role in their attendance and the interviewer probed the interviewee to discuss the actions, input and value of the people and services that supported the visit to the ED. Results: We analysed number and type of network connections and undertook a thematic analysis to identify how imagined and actual network members and influences were implicated in ED attendance. The network maps created during the interviews were examined and a typology of networks was developed and used to distinguish different types of networks informed by our reading of the data, and a Network Typology Scoring Tool, a measure of frequency of contact and relationship type in networks. Conclusions: Our study suggests that faced with acute minor illness or injury people's networks narrow: they do not (and perhaps cannot) mobilise their imagined care network because the resources or connections may not be there or are difficult to engage. In addition we identified important system drivers of behaviour, notably that these patients are often directed to the ED by 'professional influencers' including health services staff.</p

    Relational Semantics for the Paraconsistent and Paracomplete 4-valued Logic PŁ4

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    [EN] The paraconsistent and paracomplete 4-valued logic PŁ4 is originally interpreted with a two-valued Belnap-Dunn semantics. In the present paper, PŁ4 is endowed with both a ternary Routley-Meyer semantics and a binary Routley semantics together with their respective restriction to the 2 set-up cases.SIMinisterio de Ciencia e Innovación (MCIN/AEI/ 10.13039/501100011033

    Broad inhibition of plasmodium falciparum cytoadherence by (+)-epigallocatechin gallate

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    <p>Abstract</p> <p>Background</p> <p>The surface antigen P<it>f</it>EMP-1 is a key virulence factor of the human malaria parasite implicated in the cytoadherence of <it>Plasmodium falciparum </it>infected erythrocytes to a range of receptors on host endothelium. Among these host receptors, binding to ICAM-1 is related to cerebral malaria. The majority of the mortality in children with cerebral malaria is seen within 24 h of hospital admission despite the use of effective anti-parasite drugs, therefore, the development of adjunctive therapies is urgently needed.</p> <p>The polyphenolic compound (+)-epigallocatechin gallate ((+)-EGCG) has been previously evaluated for anti-adhesive properties using a small number of laboratory parasite isolates. Here, this property is further explored using a new panel of ICAM-1-binding patient isolates of <it>P. falciparum </it>to ascertain if (+)-EGCG might be effective as a broad spectrum inhibitor of ICAM-1-based cytoadherence.</p> <p>Methods</p> <p><it>Plasmodium falciparum </it>lines, including A4 and ItG as positive controls and nine new ICAM-1 binding patient isolates, were allowed to bind with ICAM-1-Fc protein under static assay conditions in the presence and absence of 50 μM (+)-EGCG. Adhesion levels of all the parasite strains were quantified by microscopy as the mean number of infected erythrocyte (IE) bound per mm<sup>2 </sup>of surface area and statistical comparisons were made to demonstrate the effect of (+)-EGCG on the binding of various parasite variants to human ICAM-1.</p> <p>Results</p> <p>This study revealed that binding of patient isolates to ICAM-1 was reduced significantly with inhibition levels of 37% in patient isolate BC-12 up to a maximum of 80% in patient isolate 8146 at 50 μM (+)-EGCG.</p> <p>Conclusion</p> <p>Evaluation of the anti-adhesive property of (+)-EGCG against a new panel of ICAM-1-binding patient isolates of <it>P. falciparum </it>showed that this inhibitor, identified as potential mimic of the L43 loop of human ICAM-1, was effective at blocking cytoadherence.</p

    The relationship between obsessions and the self: Feared and actual self-descriptions in a clinical obsessive-compulsive disorder sample

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    Cognitive models of obsessive-compulsive disorder (OCD) posit the relevance of the self in OCD, although the nature of this association is still unclear. We aimed to explore actual and feared selves and its association with obsessions and intrusions in a group of OCD patients. A group of 58 patients with OCD identified their most upsetting obsession and intrusion (non-clinical obsession) experienced in the past 3 months. These cognitions were classified as either moral-based or autogenous (obsessions n = 32; intrusions n = 26) or non-moral-based or reactive, depending on their content. Next, patients described their actual self and their feared self, that is, the person they feared being or becoming, and whether they believed these descriptions were associated with their obsessions/intrusions. Results indicate that individuals with OCD described themselves as insecure, anxious and fearful, but also as good and nice. They particularly feared a selfish, aggressive, bad, liar, coward, insecure and arrogant self. Two-thirds of the patients believed that their obsessions said something about their actual self (65.52%) and that their obsessions brought them closer to the person they do not want to be (62.06%). A third of patients believed their intrusions said something about their actual self (actual self: 30.35%; feared self: 25%), which was a significantly lower percentage than for obsessions. These associations existed independent from the content of the obsession and/or intrusion, although patients with obsessions with moral-based contents more often tended to believe that their obsessions brought them closer to the person they do not want to be. Results suggest the relevance of the real and feared selves in the maintenance of obsessions

    Mental health stigma in Spanish university students

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    Knowledge about mental health problems and previous contact are key variables in the fight against stigma. The aims of the study were: (1) to explore the level of stigma associated with mental disorders in students of different university degrees, and (2) to analyze the evolution of stigma in psychology students. Two groups completed the Attribution Questionnaire (AQ-27). Group 1 consisted of 392 first-year students of the different degrees evaluated (Mage= 18.59 years, SD= 1.29, 60% female), and group 2 consisted of 152 third-year Psychology undergraduates (Mage= 24.35 years, SD= 8.97, 73.4% female). Group 1 students with previous contact with mental disorders showed fewer stigmatizing attitudes. Differences were observed according to grade level. Group 2 showed lower levels of stigma throughout the academic year. The results support the effectiveness that mental health education and awareness-raising interventions through contact with people with mental health problems can have in reducing stigma
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