A defense of the ambiguity theory of \u27knows\u27

In recent years, questions regarding the truth conditions of knowledge ascriptions (sentences of the form ‘S knows that P’ where S is a subject and P a proposition) and knowledge denials (sentences of the form ‘S doesn’t know that P’) have been at the fore of a certain sector of analytic epistemology and philosophy of language. These questions include “How do we determine the truth conditions of a particular knowledge ascription or denial?”, “What sorts of factors are relevant in this determination?”, and “Is context among the relevant factors in a non-trivial way, and if so, how?” A variety of proposals have been generated in order to answer these questions—including proposals that offer a primarily semantic response. However, very little attention has been given to the possibility that part of the best answer to these questions about the truth conditions for knowledge ascriptions and denials is to posit that ‘knowledge’, ‘knows’, and their cognate terms are ambiguous. This dissertation offers a defense of a proposal along these lines. More specifically this dissertation is a defense of the ambiguity theory of ‘knows’. The ambiguity theory of ‘knows’ is the view ‘knows’ and its cognates have more than one propositional sense (i.e. a sense that can properly be used in ‘knows that’ constructions) and that which sense of ‘knows’ is being employed in a knowledge ascription or denial plays a role in fixing the truth conditions of a knowledge ascription (in virtue of contributing to the meaning of the claim). In this dissertation, this claim is defended first by making clear how the ambiguity theory differs from others proposals on offer, second, by comparing the ambiguity theory to other leading proposals and arguing that the ambiguity theory fares as well if not better, and third, by providing other independent arguments in favor of the view. My hope is that the work done here will give the ambiguity theory a more prominent presence in the relevant philosophical debates

Quantum Metallicity on the High-Field Side of the Superconductor-Insulator Transition

We investigate ultrathin superconducting TiN films, which are very close to the localization threshold. Perpendicular magnetic field drives the films from the superconducting to an insulating state, with very high resistance. Further increase of the magnetic field leads to an exponential decay of the resistance towards a finite value. In the limit of low temperatures, the saturation value can be very accurately extrapolated to the universal quantum resistance h/e^2. Our analysis suggests that at high magnetic fields a new ground state, distinct from the normal metallic state occurring above the superconducting transition temperature, is formed. A comparison with other studies on different materials indicates that the quantum metallic phase following the magnetic-field-induced insulating phase is a generic property of systems close to the disorder-driven superconductor-insulator transition.Comment: 4 pages, 4 figures, published versio

Bullous lesions at polyethylene glycol interferon-alpha-2a inoculation site in a hepatitis C virus-infected subject.

Sir, The recent introduction of polyethylene glycol interferon (PEG-IFN) for treatment of hepatitis C virus (HCV) has led to reports of both widespread and localized dermatological manifestations as side-effects. Widespread manifestations comprise hair loss, pruritus, generalized eczema, hyperpigmentation tongue, vitiligo and cutaneous sarcoidosis (1–4). Localized manifestations include cutaneous ulcerations and cutaneous local necrosis at the inoculation site, with both non-pegylated IFN (5) and PEG-IFN-α-2b (6, 7). We report here a case of bullous lesion at the inoculation site of PEG-IFN-α-2a in a patient with chronic HCV-correlated hepatopathy

Fluid dynamics and blood damage in the dilated ascending aorta after mechanical prosthetic valve implantation: an in vitro study

The implantation of aortic valve prostheses is often associated with the dilation of the ascending aorta. It is well known that the modification of the fluid dynamics induced by both the prosthetic valve and aortic dilation may, in turn, promote further vessel remodelling. Besides, when the prosthesis is mechanical, a major concern is the blood cell damage and platelet activation which requires a lifelong anticoagulant therapy, which in turn is an additional significant factor of comorbidity. We analysed in vitro the combined effect of the presence of a bileaflet mechanical aortic valve and the dilation of the aortic root in patient specific laboratory models. Three model aortas with increasing degree of dilation, hosted in a mock loop reproducing the heart flow pulsatility, were investigated. The measurement of the time-resolved velocity field allowed the analysis of the general structure of the flow and shear strain-rate distribution. Additionally, the Blood Damage Indexes (BDIs) for both haemolysis and platelet activation were computed along synthetic particle trajectories. Results suggest that a feedback process can be triggered since the aortic dilation tends to decrease the shear stresses at the walls and favour blood stasis: two factors that are known to promote vessel remodelling. Secondly, the analysis of BDIs shows that aortic dilation significantly increases the damage index for haemolysis, whereas a similar effect is not shown when focusing on platelet activation. Graphical abstract: [Figure not available: see fulltext.

Person Re-identification Using Clustering Ensemble Prototypes

Abstract. This paper presents an appearance-based model to deal with the person re-identification problem. Usually in a crowded scene, it is ob-served that, the appearances of most people are similar with regard to the combination of attire. In such situation it is a difficult task to distin-guish an individual from a group of alike looking individuals and yields an ambiguity in recognition for re-identification. The proper organiza-tion of the individuals based on the appearance characteristics leads to recognize the target individual by comparing with a particular group of similar looking individuals. To reconstruct a group of individual accord-ing to their appearance is a crucial task for person re-identification. In this work we focus on unsupervised based clustering ensemble approach for discovering prototypes where each prototype represents similar set of gallery image instances. The formation of each prototype depends upon the appearance characteristics of gallery instances. The estimation of k-NN classifier is employed to specify a prototype to a given probe image. The similarity measure computation is performed between the probe and a subset of gallery images, that shares the same prototype with the probe and thus reduces the number of comparisons. Re-identification perfor-mance on benchmark datasets are presented using cumulative matching characteristic (CMC) curves.

Propolis consumption reduces Nosema ceranae infection of European honey bees (Apis mellifera)

Nosema ceranae is a widespread obligate intracellular parasite of the ventriculus of many species of honey bee (Apis), including the Western honey bee Apis mellifera, in which it may lead to colony death. It can be controlled in A. mellifera by feeding the antibiotic fumagillin to a colony, though this product is toxic to humans and its use has now been banned in many countries, so in beekeeping, there exists a need for alternative and safe products effective against N. ceranae. Honeybees produce propolis from resinous substances collected from plants and use it to protect their nest from parasites and pathogens; propolis is thought to decrease the microbial load of the hive. We hypothesized that propolis might also reduce N. ceranae infection of individual bees and that they might consume propolis as a form of self-medication. To test these hypotheses, we evaluated the effects of an ethanolic extract of propolis administered orally on the longevity and spore load of experimentally N. ceranae-infected worker bees and also tested whether infected bees were more attracted to, and consumed a greater proportion of, a diet containing propolis in comparison to uninfected bees. Propolis extracts and ethanol (solvent control) increased the lifespan of N. ceranae-infected bees, but only propolis extract significantly reduced spore load. Our propolis extract primarily contained derivatives of caffeic acid, ferulic acid, ellagic acid and quercetin. Choice, scan sampling and food consumption tests did not reveal any preference of N. ceranae-infected bees for commercial candy containing propolis. Our research supports the hypothesis that propolis represents an effective and safe product to control N. ceranae but worker bees seem not to use it to self-medicate when infected with this pathogen