652 research outputs found

    Cultural relativism and the discourse of intercultural communication: aporias of praxis in the intercultural public sphere

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    The premise of much intercultural communication pedagogy and research is to educate people from different cultures towards open and transformative positions of mutual understanding and respect. This discourse in the instance of its articulation realises and sustains Intercultural Communication epistemologically – as an academic field of social enquiry, and judgementally – as one which locates itself on a moral terrain. By adopting an ethical stance towards difference, the discourse of intercultural communication finds itself caught in a series of aporias, or performative contradictions, where interculturalists are projected simultaneously into positions of cultural relativism on the one hand and ideological totalism on the other. Such aporias arise because the theoretical premises upon which the discourse relies are problematic. We trace these thematics to a politics of presence operating within the discourse of intercultural communication and links this to questions of judgement and truth in the intercultural public sphere. We propose that the politics of presence be set aside in favour of an intercultural praxis which is oriented to responsibility rather than to truth

    Magnetic Determination of Hc2H_{c2} under Accurate Alignment in (TMTSF)2_2ClO4_4

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    Cantilever magnetometry has been used to measure the upper critical magnetic field Hc2H_{c2} of the quasi-one dimensional molecular organic superconductor (TMTSF)2_2ClO4_4. From simultaneous resistivity and torque magnetization experiments conducted under precise field alignment, Hc2H_{c2} at low temperature is shown to reach 5T, nearly twice the Pauli paramagnetic limit imposed on spin singlet superconductors. These results constitute the first thermodynamic evidence for a large Hc2H_{c2} in this system and provide support for spin triplet pairing in this unconventional superconductorComment: Submitted July 1, 2003, Accepted December 9, 2003, Physical Review Letter

    Could a Protist help us understand cancer?

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    Cancer is a deadly disease which affects millions of people globally. Cancer ultimately arises from dysregulation of growth pathways, leading to loss of cell cycle control and tumor formation. Cancer cells maintain constant cell division, evade immune detection, ignore signals for apoptosis, and may acquire the ability to degrade the extracellular matrix and metastasize. Tetrahymena thermophila are free-living (non-parasitic) ciliated unicellular eukaryotes belonging to Kingdom Protista. They are often used as a model system because they are relatively inexpensive and easy to culture and maintain. In addition, it is relatively simple to grow and harvest large numbers of cells for biochemical applications such as protein, DNA, or RNA purification. Because of their adaptability as a model system, we asked whether whether Tetrahymena possessed two common pathways often dysregulated in cancer; the Wnt signaling pathway and the Ras signaling pathway. In order to test our hypothesis, we used the Tetrahymena genome database to search for homologs of Wnt, Ras, and Raf. In addition, we used a Wnt agonist and an antagonist of Ras/Raf inhibition to determine whether the mitotic rate would be affected. While the Wnt agonist had no significant affect on mitosis, the Ras/Raf inhibitor significantly decreased mitotic rate in this organism. We also found homologs of Ras and Raf in the Tetrahymena genome database. Further studies are needed in order to obtain an accurate dose-response curve with the Ras/Raf inhibitor, BAY-293

    Characterization of a Laminin-like Protein in the Kinetodesmal Fibers of Tetrahymena thermophila

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    Tetrahymena thermophila are free-living ciliated organisms belonging to Kingdom Protista. These organisms possess large numbers of cilia that are used for feeding as well as locomotion. The cilia are attached to microtubule organizing centers (MTOC) called basal bodies, which are rich in centrin, a calcium binding protein present in MTOCs. Because of the mechanical stress that ciliary beating puts on the plasma membrane, these cells have kinetodesmal fibers, composed of bundled coiled-coil proteins which grow from the proximal end of the basal bodies and stabilize the plasma membrane. Laminin is a cross-linking protein found in the extracellular matrix of animals. Using an antibody against laminin-b1, we found that the antibody localized to kinetodesmal fibers which overlapped the basal bodies stained by the anti-centrin antibody. To determine whether these proteins were in the same complex, we did co-immunoprecipitation using both our anti-centrin and anti-laminin antibodies. Both antibodies precipitated centrin (a doublet at 20 kD) as well as a number of presumed laminin-like proteins between 37 and 50 kD. We also found a number of laminin homologues in the Tetrahymena Genome Database. Further studies will be needed to determine which of these putative proteins is present in the kinetodesmal fiber

    Efficacy of λ-cyhalothrin, amitraz, and phoxim against the poultry red mite Dermanyssus gallinae De Geer, 1778 (Mesostigmata: Dermanyssidae): an eight-year survey

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    Dermanyssus gallinae (De Geer, 1778) is a major problem for the poultry industry worldwide, as it negatively affects virtually all kinds of rearing systems. Therefore, the control of infestation has become a routine process, and its economic cost is constantly increasing. Until now, most of the control strategies have relied on the use of synthetic chemical drugs, but their efficacy is often questioned by the emergence and diffusion of resistant mite populations. With this in mind, the efficacy of λ-cyhalothrin, amitraz, and phoxim has been verified by testing them against 86 mite populations collected from the same number of poultry farms in Italy from 2008 to 2015. Assays were performed according to the filter paper method using the recommended, half, quarter, double and quadruple doses. The results showed that phoxim and amitraz were the most effective acaricides (median efficacies 80.35% and 80.83%, respectively), but amitraz exhibited a sharp fall in its efficacy during 2011 and 2012, while phoxim maintained its high effectiveness up to 2015, when it dropped. The overall median efficacy of λ-cyhalothrin was 58.33%. The data also highlighted the importance of the use of the right concentration, as an increase in dosage was not always useful against resistant populations, while its reduction also diminished efficacy, simultaneously increasing the risk for the development of resistance

    Learning ability correlates with brain atrophy and disability progression in RRMS

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    Objective To assess the prognostic value of practice effect on Paced Auditory Serial Addition Test (PASAT) in multiple sclerosis. Methods We compared screening (day a '14) and baseline (day 0) PASAT scores of 1009 patients from the FTY720 Research Evaluating Effects of Daily Oral therapy in Multiple Sclerosis (FREEDOMS) trial. We grouped patients into high and low learners if their PASAT score change was above or below the median change in their screening PASAT quartile group. We used Wilcoxon test to compare baseline disease characteristics between high and low learners, and multiple regression models to assess the respective impact of learning ability, baseline normalised brain volume and treatment on brain volume loss and 6-month confirmed disability progression over 2 years. Results The mean PASAT score at screening was 45.38, increasing on average by 3.18 from day a '14 to day 0. High learners were younger (p=0.003), had lower Expanded Disability Status Scale score (p=0.031), higher brain volume (p<0.001) and lower T2 lesion volume (p=0.009) at baseline. Learning status was not significantly associated with disability progression (HR=0.953, p=0.779), when adjusting for baseline normalised brain volume, screening PASAT score and treatment arm. However, the effect of fingolimod on disability progression was more pronounced in high learners (HR=0.396, p<0.001) than in low learners (HR=0.798, p=0.351; p for interaction=0.05). Brain volume loss at month 24 tended to be higher in low learners (0.17%, p=0.058), after adjusting for the same covariates. Conclusions Short-term practice effects on PASAT are related to brain volume, disease severity and age and have clinically meaningful prognostic implications. High learners benefited more from fingolimod treatment

    Increasing pattern recognition accuracy for chemical sensing by evolutionary based drift compensation

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    Artificial olfaction systems, which mimic human olfaction by using arrays of gas chemical sensors combined with pattern recognition methods, represent a potentially low-cost tool in many areas of industry such as perfumery, food and drink production, clinical diagnosis, health and safety, environmental monitoring and process control. However, successful applications of these systems are still largely limited to specialized laboratories. Sensor drift, i.e., the lack of a sensor's stability over time, still limits real in dustrial setups. This paper presents and discusses an evolutionary based adaptive drift-correction method designed to work with state-of-the-art classification systems. The proposed approach exploits a cutting-edge evolutionary strategy to iteratively tweak the coefficients of a linear transformation which can transparently correct raw sensors' measures thus mitigating the negative effects of the drift. The method learns the optimal correction strategy without the use of models or other hypotheses on the behavior of the physical chemical sensors

    Possible Triplet Electron Pairing and an Anisotropic Spin Susceptibility in Organic Superconductors (TMTSF)_2 X

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    We argue that (TMTSF)_2 PF_6 compound under pressure is likely a triplet superconductor with a vector order parameter d(k) \equiv (d_a(k) \neq 0, d_c(k) = ?, d_{b'}(k) = 0); |d_a(k)| > |d_c(k)|. It corresponds to an anisotropic spin susceptibility at T=0: \chi_{b'} = \chi_0, \chi_a \ll \chi_0, where \chi_0 is its value in a metallic phase. [The spin quantization axis, z, is parallel to a so-called b'-axis]. We show that the suggested order parameter explains why the upper critical field along the b'-axis exceeds all paramagnetic limiting fields, including that for a nonuniform superconducting state, whereas the upper critical field along the a-axis (a \perp b') is limited by the Pauli paramagnetic effects [I. J. Lee, M. J. Naughton, G. M. Danner and P. M. Chaikin, Phys. Rev. Lett. 78, 3555 (1997)]. The triplet order parameter is in agreement with the recent Knight shift measurements by I. J. Lee et al. as well as with the early results on a destruction of superconductivity by nonmagnetic impurities and on the absence of the Hebel-Slichter peak in the NMR relaxation rate.Comment: 4 pages, 1 eps figur
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