2,671 research outputs found

    A proper understanding of Millikan

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    Ruth Millikan’s teleological theory of mental content is complex and often misunderstood. This paper motivates and clarifies some of the complexities of the theory, and shows that paying careful attention to its details yields answers to a number of common objections to teleological theories, in particular, the problem of novel mental states, the problem of functionally false beliefs, and problems about indeterminacy or multiplicity of function

    The evolution and development of visual perspective taking

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    I outline three conceptions of seeing that a creature might possess: ‘the headlamp conception,’ which involves an understanding of the causal connections between gazing at an object, certain mental states, and behavior; ‘the stage lights conception,’ which involves an understanding of the selective nature of visual attention; and seeing-as. I argue that infants and various nonhumans possess the headlamp conception. There is also evidence that chimpanzees and 3-year-old children have some grasp of seeing-as. However, due to a dearth of studies, there is no evidence that infants or nonhumans possess the stage lights conception of seeing. I outline the kinds of experiments that are needed, and what we stand to learn about the evolution and development of perspective taking

    Duality and ontology

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    A ‘duality’ is a formal mapping between the spaces of solutions of two empirically equivalent theories. In recent times, dualities have been found to be pervasive in string theory and quantum field theory. Naïvely interpreted, duality-related theories appear to make very different ontological claims about the world—differing in e.g. space-time structure, fundamental ontology, and mereological structure. In light of this, duality-related theories raise questions familiar from discussions of underdetermination in the philosophy of science: in the presence of dual theories, what is one to say about the ontology of the world? In this paper, we undertake a comprehensive and non-technical survey of the landscape of possible ontological interpretations of duality-related theories. We provide a significantly enriched and clarified taxonomy of options—several of which are novel to the literature

    Unfolding dynamics of proteins under applied force

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    Understanding the mechanisms of protein folding is a major challenge that is being addressed effectively by collaboration between researchers in the physical and life sciences. Recently, it has become possible to mechanically unfold proteins by pulling on their two termini using local force probes such as the atomic force microscope. Here, we present data from experiments in which synthetic protein polymers designed to mimic naturally occurring polyproteins have been mechanically unfolded. For many years protein folding dynamics have been studied using chemical denaturation, and we therefore firstly discuss our mechanical unfolding data in the context of such experiments and show that the two unfolding mechanisms are not the same, at least for the proteins studied here. We also report unexpected observations that indicate a history effect in the observed unfolding forces of polymeric proteins and explain this in terms of the changing number of domains remaining to unfold and the increasing compliance of the lengthening unstructured polypeptide chain produced each time a domain unfolds

    Gene therapy with Angiotensin-(1-9) preserves left ventricular systolic function after myocardial infarction

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    BACKGROUND: Angiotensin-(1-9) [Ang-(1-9)] is a novel peptide of the counter-regulatory axis of the renin angiotensin system previously demonstrated to have therapeutic potential in hypertensive cardiomyopathy when administered via osmotic minipump in mice. Here, we investigate whether gene transfer of Ang-(1-9) is cardioprotective in a murine model of myocardial infarction (MI). OBJECTIVES: To evaluate effects of Ang-(1-9) gene therapy on myocardial structural and functional remodeling post infarction. METHODS: C57BL/6 mice underwent permanent left anterior descending coronary artery ligation and cardiac function was assessed using echocardiography for 8 weeks followed by a terminal measurement of left ventricular (LV) pressure-volume loops. Ang-(1-9) was delivered by adeno-associated viral vector via single tail vein injection immediately following induction of MI. Direct effects of Ang-(1-9) on cardiomyocyte excitation–contraction coupling and cardiac contraction were evaluated in isolated mouse and human cardiomyocytes and in an ex vivo Langendorff perfused whole heart model. RESULTS: Gene delivery of Ang-(1-9) significantly reduced sudden cardiac death post-MI. Pressure–volume measurements revealed complete restoration of end systolic pressure, ejection fraction, end systolic volume and the end diastolic pressure–volume relationship by Ang-(1-9) treatment. Stroke volume and cardiac output were significantly increased versus sham. Histological analysis revealed only mild effects on cardiac hypertrophy and fibrosis, but a significant increase in scar thickness. Direct assessment of Ang-(1-9) on isolated cardiomyocytes demonstrated a positive inotropic effect via increasing calcium transient amplitude and increasing contractility. Ang-(1-9) increased contraction in the Langendorff model through a protein kinase A-dependent mechanism. CONCLUSIONS: Our novel findings show that Ang-(1-9) gene therapy preserves LV systolic function post-MI, restoring cardiac function. Furthermore, Ang-(1-9) has a direct effect on cardiomyocyte 3 calcium handling through a protein kinase A-dependent mechanism. These data highlight Ang-(1-9) gene therapy as a potential new strategy in the context of MI

    Comprehensive translational assessment of human-induced pluripotent stem cell derived cardiomyocytes for evaluating drug-induced arrhythmias

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    Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM) hold promise for assessment of drug-induced arrhythmias and are being considered for use under the comprehensive in vitro proarrhythmia assay (CiPA). We studied the effects of 26 drugs and 3 drug combinations on 2 commercially available iPSC-CM types using high-throughput voltage-sensitive dye and microelectrode-array assays being studied for the CiPA initiative and compared the results with clinical QT prolongation and torsade de pointes (TdP) risk. Concentration-dependent analysis comparing iPSC-CMs to clinical trial results demonstrated good correlation between drug-induced rate-corrected action potential duration and field potential duration (APDc and FPDc) prolongation and clinical trial QTc prolongation. Of 20 drugs studied that exhibit clinical QTc prolongation, 17 caused APDc prolongation (16 in Cor.4U and 13 in iCell cardiomyocytes) and 16 caused FPDc prolongation (16 in Cor.4U and 10 in iCell cardiomyocytes). Of 14 drugs that cause TdP, arrhythmias occurred with 10 drugs. Lack of arrhythmic beating in iPSC-CMs for the four remaining drugs could be due to differences in relative levels of expression of individual ion channels. iPSC-CMs responded consistently to human ether-a-go-go potassium channel blocking drugs (APD prolongation and arrhythmias) and calcium channel blocking drugs (APD shortening and prevention of arrhythmias), with a more variable response to late sodium current blocking drugs. Current results confirm the potential of iPSC-CMs for proarrhythmia prediction under CiPA, where iPSC-CM results would serve as a check to ion channel and in silico modeling prediction of proarrhythmic risk. A multi-site validation study is warranted

    Justifying the Special Theory of Relativity with Unconceived Methods

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    Many realists argue that present scientific theories will not follow the fate of past scientific theories because the former are more successful than the latter. Critics object that realists need to show that present theories have reached the level of success that warrants their truth. I reply that the special theory of relativity has been repeatedly reinforced by unconceived scientific methods, so it will be reinforced by infinitely many unconceived scientific methods. This argument for the special theory of relativity overcomes the critics’ objection, and has advantages over the no-miracle argument and the selective induction for it

    Measuring and optimising the efficiency of community hospital inpatient care for older people: the MoCHA mixed-methods study

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    Background: Community hospitals are small hospitals providing local inpatient and outpatient services. National surveys report that inpatient rehabilitation for older people is a core function but there are large differences in key performance measures. We have investigated these variations in community hospital ward performance. Objectives: (1) To measure the relative performance of community hospital wards (studies 1 and 2); (2) to identify characteristics of community hospital wards that optimise performance (studies 1 and 3); (3) to develop a web-based interactive toolkit that supports operational changes to optimise ward performance (study 4); (4) to investigate the impact of community hospital wards on secondary care use (study 5); and (5) to investigate associations between short-term community (intermediate care) services and secondary care utilisation (study 5). Methods: Study 1 – we used national data to conduct econometric estimations using stochastic frontier analysis in which a cost function was modelled using significant predictors of community hospital ward costs. Study 2 – a national postal survey was developed to collect data from a larger sample of community hospitals. Study 3 – three ethnographic case studies were performed to provide insight into less tangible aspects of community hospital ward care. Study 4 – a web-based interactive toolkit was developed by integrating the econometrics (study 1) and case study (study 3) findings. Study 5 – regression analyses were conducted using data from the Atlas of Variation Map 61 (rate of emergency admissions to hospital for people aged ≄ 75 years with a length of stay of < 24 hours) and the National Audit of Intermediate Care. Results: Community hospital ward efficiency is comparable with the NHS acute hospital sector (mean cost efficiency 0.83, range 0.72–0.92). The rank order of community hospital ward efficiencies was distinguished to facilitate learning across the sector. On average, if all community hospital wards were operating in line with the highest cost efficiency, savings of 17% (or ÂŁ47M per year) could be achieved (price year 2013/14) for our sample of 101 wards. Significant economies of scale were found: a 1% rise in output was associated with an average 0.85% increase in costs. We were unable to obtain a larger community hospital sample because of the low response rate to our national survey. The case studies identified how rehabilitation was delivered through collaborative, interdisciplinary working; interprofessional communication; and meaningful patient and family engagement. We also developed insight into patients’ recovery trajectories and care transitions. The web-based interactive toolkit was established [http://mocha. nhsbenchmarking.nhs.uk/ (accessed 9 September 2019)]. The crisis response team type of intermediate care, but not community hospitals, had a statistically significant negative association with emergency admissions. Limitations: The econometric analyses were based on cross-sectional data and were also limited by missing data. The low response rate to our national survey means that we cannot extrapolate reliably from our community hospital sample. Conclusions: The results suggest that significant community hospital ward savings may be realised by improving modifiable performance factors that might be augmented further by economies of scale. Future work: How less efficient hospitals might reduce costs and sustain quality requires further research

    Type 2 Diabetes Risk Alleles Are Associated With Reduced Size at Birth

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    OBJECTIVE: Low birth weight is associated with an increased risk of type 2 diabetes. The mechanisms underlying this association are unknown and may represent intrauterine programming or two phenotypes of one genotype. The fetal insulin hypothesis proposes that common genetic variants that reduce insulin secretion or action may predispose to type 2 diabetes and also reduce birth weight, since insulin is a key fetal growth factor. We tested whether common genetic variants that predispose to type 2 diabetes also reduce birth weight. RESEARCH DESIGN AND METHODS: We genotyped single-nucleotide polymorphisms (SNPs) at five recently identified type 2 diabetes loci (CDKAL1, CDKN2A/B, HHEX-IDE, IGF2BP2, and SLC30A8) in 7,986 mothers and 19,200 offspring from four studies of white Europeans. We tested the association between maternal or fetal genotype at each locus and birth weight of the offspring. RESULTS: We found that type 2 diabetes risk alleles at the CDKAL1 and HHEX-IDE loci were associated with reduced birth weight when inherited by the fetus (21 g [95% CI 11-31], P = 2 x 10(-5), and 14 g [4-23], P = 0.004, lower birth weight per risk allele, respectively). The 4% of offspring carrying four risk alleles at these two loci were 80 g (95% CI 39-120) lighter at birth than the 8% carrying none (P(trend) = 5 x 10(-7)). There were no associations between birth weight and fetal genotypes at the three other loci or maternal genotypes at any locus. CONCLUSIONS: Our results are in keeping with the fetal insulin hypothesis and provide robust evidence that common disease-associated variants can alter size at birth directly through the fetal genotype
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