1,097 research outputs found

    Seeing motion and apparent motion

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    In apparent motion experiments, participants are presented with what is in fact a succession of two brief stationary stimuli at two different locations, but they report an impression of movement. Philosophers have recently debated whether apparent motion provides evidence in favour of a particular account of the nature of temporal experience. I argue that the existing discussion in this area is premised on a mistaken view of the phenomenology of apparent motion and, as a result, the space of possible philosophical positions has not yet been fully explored. In particular, I argue that the existence of apparent motion is compatible with an account of the nature of temporal experience that involves a version of direct realism. In doing so, I also argue against two other claims often made about apparent motion, viz. that apparent motion is the psychological phenomenon that underlies motion experience in the cinema, and that apparent motion is subjectively indistinguishable from real motion

    Suppression of Superconducting Critical Current Density by Small Flux Jumps in MgB2MgB_2 Thin Films

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    By doing magnetization measurements during magnetic field sweeps on thin films of the new superconductor MgB2MgB_2, it is found that in a low temperature and low field region small flux jumps are taking place. This effect strongly suppresses the central magnetization peak leading to reduced nominal superconducting critical current density at low temperatures. A borderline for this effect to occur is determined on the field-temperature (H-T) phase diagram. It is suggested that the small size of the flux jumps in films is due to the higher density of small defects and the relatively easy thermal diffusion in thin films in comparison with bulk samples.Comment: 7 figures Phys. Rev. B accepted scheduled issue: 01 Feb 200

    Generation of folk song melodies using Bayes transforms

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    The paper introduces the `Bayes transform', a mathematical procedure for putting data into a hierarchical representation. Applicable to any type of data, the procedure yields interesting results when applied to sequences. In this case, the representation obtained implicitly models the repetition hierarchy of the source. There are then natural applications to music. Derivation of Bayes transforms can be the means of determining the repetition hierarchy of note sequences (melodies) in an empirical and domain-general way. The paper investigates application of this approach to Folk Song, examining the results that can be obtained by treating such transforms as generative models

    Local threshold field for dendritic instability in superconducting MgB2 films

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    Using magneto-optical imaging the phenomenon of dendritic flux penetration in superconducting films was studied. Flux dendrites were abruptly formed in a 300 nm thick film of MgB2 by applying a perpendicular magnetic field. Detailed measurements of flux density distributions show that there exists a local threshold field controlling the nucleation and termination of the dendritic growth. At 4 K the local threshold field is close to 12 mT in this sample, where the critical current density is 10^7 A/cm^2. The dendritic instability in thin films is believed to be of thermo-magnetic origin, but the existence of a local threshold field, and its small value are features that distinctly contrast the thermo-magnetic instability (flux jumps) in bulk superconductors.Comment: 6 pages, 6 figures, submitted to Phys. Rev.

    How payment for research participation can be coercive

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    The idea that payment for research participation can be coercive appears widespread among research ethics committee members, researchers, and regulatory bodies. Yet analysis of the concept of coercion by philosophers and bioethicists has mostly concluded that payment does not coerce, because coercion necessarily involves threats, not offers. In this article we aim to resolve this disagreement by distinguishing between two distinct but overlapping concepts of coercion. Consent- undermining coercion marks out certain actions as impermissible and certain agreements as unenforceable. By contrast, coercion as subjection indicates a way in which someone’s interests can be partially set back in virtue of being subject to another’s foreign will. While offers of payment do not normally constitute consent-undermining coercion, they do sometimes constitute coercion as subjection. We offer an analysis of coercion as subjection and propose three possible practical responses to worries about the coerciveness of payment

    Experiments in vortex avalanches

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    Avalanche dynamics is found in many phenomena spanning from earthquakes to the evolution of species. It can be also found in vortex matter when a type II superconductor is externally driven, for example, by increasing the magnetic field. Vortex avalanches associated with thermal instabilities can be an undesirable effect for applications, but "dynamically driven" avalanches emerging from the competition between intervortex interactions and quenched disorder constitute an interesting scenario to test theoretical ideas related with non-equilibrium dynamics. However, differently from the equilibrium phases of vortex matter in type II superconductors, the study of the corresponding dynamical phases - in which avalanches can play a role - is still in its infancy. In this paper we critically review relevant experiments performed in the last decade or so, emphasizing the ability of different experimental techniques to establish the nature and statistical properties of the observed avalanche behavior.Comment: To be published in Reviews of Modern Physics April 2004. 17 page

    The Allen Telescope Array: The First Widefield, Panchromatic, Snapshot Radio Camera for Radio Astronomy and SETI

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    The first 42 elements of the Allen Telescope Array (ATA-42) are beginning to deliver data at the Hat Creek Radio Observatory in Northern California. Scientists and engineers are actively exploiting all of the flexibility designed into this innovative instrument for simultaneously conducting surveys of the astrophysical sky and conducting searches for distant technological civilizations. This paper summarizes the design elements of the ATA, the cost savings made possible by the use of COTS components, and the cost/performance trades that eventually enabled this first snapshot radio camera. The fundamental scientific program of this new telescope is varied and exciting; some of the first astronomical results will be discussed.Comment: Special Issue of Proceedings of the IEEE: "Advances in Radio Telescopes", Baars,J. Thompson,R., D'Addario, L., eds, 2009, in pres

    Dobra proizvođačka praksa: uloga domaćih proizvođača i nadležnih tijela

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    In every country, a manufacturer of medicinal products for either human or veterinary use is required to operate in compliance with local legislation effect that they are committed to abide by the same standards. The candidate countries transpose the acquis into their national legislation, including the good manufacturing practice (GMP). Consequently, the local manufacturer is required to strictly comply with GMP and the manufacturing licence, including for medicinal products exclusively intended for export. A vital role is also played by national regulatory authorities, in Croatia by the Agency for Medicinal Products and Medical Devices which issues the manufacturing licence, GMP certifi cate, and the Certifi cate of a Pharmaceutical Product (CPP) and conducts laboratory control of products. GMP inspection is carried out by the Pharmaceutical Inspectorate with the Ministry of Health and Social Welfare. Both authorities are responsible only for human medicines. There are legislative issues not yet harmonised with the acquis, but as a country aspiring for the EU membership, Croatia is expected to demonstrate that its industry and competent authorities are able to conform to current requirements and thus fully adhere to the integrated European regulatory network. Hence the importance of strengthening the institutional capacity of the competent authorities, as insuffi cient resources may have a direct bearing on patients by limiting their access to affordable treatment.U svakoj zemlji proizvođač lijekova za humanu ili za veterinarsku uporabu obavezan je poslovati sukladno lokalnom zakonodavstvu, koje je u EU usklađeno za sve članice koje moraju poštivati jednake standarde. Zemlje kandidati za članstvo ugrađuju europsko zakonodavstvo u nacionalno i na taj način implementiraju dobru proizvođačku praksu (GMP). Sukladno tomu, proizvođač lijeka obvezan je osigurati da se svi proizvodni postupci za lijekove izvode u skladu s dobrom proizvođačkom praksom i proizvodnom dozvolom uključujući i lijekove koji su namijenjeni samo za izvoz. Ovdje je nezaobilazna i uloga nacionalnih regulatornih tijela posebno Agencije za lijekove i medicinske proizvode koja izdaje proizvodnu dozvolu, GMP certifi kate i certifi kate o farmaceutskom proizvodu - lijeku (CPP) te provodi laboratorijsku kontrolu proizvoda. GMP inspekciju provodi farmaceutski inspektorat koji je u sastavu Ministarstva zdravstva i socijalne skrbi. Oba su tijela nadležna samo za lijekove za humanu uporabu. Postoje još neka neusklađena pitanja što se tiče prihvaćanja Pravne stečevine na ovome polju, ali kako je Hrvatska zemlja kandidat za punopravno članstvo u EU, očekuje se da će moći demonstrirati da njezina industrija i nadležna tijela poštuju važeće zahtjeve EU i tako potpuno pristupaju europskoj regulatornoj mreži. Stoga je važno jačati institucionalni kapacitet nadležnih tijela, jer nedostatni potencijali mogu izravno utjecati na pacijente ograničavajući im pristup dostupnim terapijama

    Paying Refugees to Leave

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    States are increasingly paying refugees to repatriate, hoping to decrease the number of refugees residing within their borders. Drawing on in-depth interviews from East Africa and data from Israeli Labour Statistics, I provide a description of such payment schemes and consider whether they are morally permissible. In doing so, I address two types of cases. In the first type of case, governments pay refugees to repatriate to high-risk countries, never coercing them into returning. I argue that such payments are permissible if refugees’ choices are voluntary and if states allow refugees to return to the host country in the event of an emergency. I then describe cases where states detain refugees, and non-governmental organisations provide their own payments to refugees wishing to repatriate. In such cases, non-governmental organisations are only permitted to provide payments if the funds are sufficient to ensure post-return safety and if providing payments does not reinforce the government’s detention policy
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