185 research outputs found
Ă-Methylphenylethylamines: Common fragmentation pathways with amphetamines in electrospray ionization collision-induced dissociation
β-Methylphenylethylamines are positional isomers of amphetamines and have been discovered in sporting supplements. Although the fragmentation of the β-methylphenylethylamine and N-methyl-β-methylphenylethylamine in gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) systems is significantly different to their amphetamine and methylamphetamine isomers, under electrospray ionization commonly used in liquid chromatography-mass spectrometry (LC-MS) systems, the fragmentation of each of the isomeric pairs is almost identical. The similarities in fragmentation make it possible for the misidentification of the β-methylphenylethylamines as the illicit amphetamines. It is proposed that the similarities are due to a fragmentation pathway involving a common phenonium ion intermediate. By careful control of fragmentation energies in liquid chromatography-tandem mass spectrometry (LC-MS/MS) systems and/or close examination of the relative abundances of product ions formed by collision-induced dissociation (qualifier ratios), it is possible to distinguish the β-methylphenylethylamines from the amphetamines, even if significant retention time separation is not achieved. In liquid chromatography-electrospray ionization-quadrupole time of flight (LC-ESI-QTOF) systems the mass spectra of the β-methylphenylethylamines are identical to their amphetamine isomers. In such systems, retention time separation of the isomers is critical to avoid misidentification. During this study β-methylphenylethylamine and N-methyl-β-methylphenylethylamine have been identified in commercially available sporting supplements and oral fluid samples taken during the course of road-side drugs-in-drivers and workplace testing programmes
A probabilistic analysis of argument cogency
This paper offers a probabilistic treatment of the conditions for argument cogency as endorsed in informal logic: acceptability, relevance, and sufficiency. Treating a natural language argument as a reason-claim-complex, our analysis identifies content features of defeasible argument on which the RSA conditions depend, namely: change in the commitment to the reason, the reasonâs sensitivity and selectivity to the claim, oneâs prior commitment to the claim, and the contextually determined thresholds of acceptability for reasons and for claims. Results contrast with, and may indeed serve to correct, the informal understanding and applications of the RSA criteria concerning their conceptual dependence, their function as update-thresholds, and their status as obligatory rather than permissive norms, but also show how these formal and informal normative approachs can in fact align
A classification system for argumentation schemes
This paper explains the importance of classifying argumentation schemes, and outlines how schemes are being used in current research in artificial intelligence and computational linguistics on argument mining. It provides a survey of the literature on scheme classification. What are so far generally taken to represent a set of the most widely useful defeasible argumentation schemes are surveyed and explained systematically, including some that are difficult to classify. A new classification system covering these centrally important schemes is built
Arguments from parallel reasoning
Argumentation is a co-production by a proponent and an opponent who engage in a critical examination of their difference of opinion, aiming to resolve it on the merits of both sides, or so I assume in this paper. I shall investigate the consequences of this view for a particular type of argument from analogy, called argument from parallel reasoning, that has been discussed in some detail by Woods and Hudak in 1989. Suppose, a proponent contends that we should allow camera surveillance with drones by the Amsterdam police, on account of these drones' cost-effectiveness. Suppose further, that the opponent addressed makes it clear that she acknowledges the drones' cost-effectiveness, as well as the relevance of this consideration, but that she remains, nevertheless, critical towards the proponent's thesis for worrying about intrusions on privacy. In such a case, the proponent may consider it to be expedient to put forward an argument such as: âYou would consent to cameras on satellites on account of their cost-effectiveness, and despite privacy considerations. Well, reasoning from cost-effectiveness to cameras on drones, despite privacy considerations, is comparable to reasoning from cost-effectiveness to cameras on satellites, despite privacy considerations.â How are such arguments generated in dialogue, and in which circumstances, if any, is such an indirect, and possibly even superficial way of arguing correct? I shall illustrate my findings with an atypical example of an argument from analogy, put forward by John Stuart Mill, in favour of the existence of other minds
An information-based solution for the puzzle of testimony and trust
Original article can be found at: http://www.tandf.co.uk/ Copyright Taylor & FrancisIn this paper, I offer a contribution to the debate on testimony that rests on three elements: the definition of semantic information (Floridi, 2004), the analysis of trust as a second-order property of first-order relations provided in (Taddeo, 2010), and Floridiâs Network Theory of Account (NTA) (Floridi, Forthcoming). I argue that testimony transmits semantic information and it is neither grounded on trust nor is it justified by it. Instead, I show that testimony is an occurrence of a first-order relation of communication affected by the second-order property of trust. I then defend the view that an epistemic agent can acquire some knowledge, on the basis of the information communicated through testimony, if and only if the agent is able to connect the transmitted information to the conceptual network of interrelation to which it belongs. I refer to Floridiâs NTA to show how such a network allows the epistemic agent to achieve knowledge on the basis of semantic information.Peer reviewe
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