439 research outputs found

    A Dynamic Approach to Rhythm in Language: Toward a Temporal Phonology

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    It is proposed that the theory of dynamical systems offers appropriate tools to model many phonological aspects of both speech production and perception. A dynamic account of speech rhythm is shown to be useful for description of both Japanese mora timing and English timing in a phrase repetition task. This orientation contrasts fundamentally with the more familiar symbolic approach to phonology, in which time is modeled only with sequentially arrayed symbols. It is proposed that an adaptive oscillator offers a useful model for perceptual entrainment (or `locking in') to the temporal patterns of speech production. This helps to explain why speech is often perceived to be more regular than experimental measurements seem to justify. Because dynamic models deal with real time, they also help us understand how languages can differ in their temporal detail---contributing to foreign accents, for example. The fact that languages differ greatly in their temporal detail suggests that these effects are not mere motor universals, but that dynamical models are intrinsic components of the phonological characterization of language.Comment: 31 pages; compressed, uuencoded Postscrip

    Online Security in the Middle East and North Africa: A Survey of Perceptions, Knowledge, and Practice

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    Digital communication has become a more perilous activity, particularly for activists, political dissidents, and independent media. The recent surge in digital activism that has helped to shape the Arab spring has been met with stiff resistance by governments in the region intent on reducing the impact of digital organizing and independent media. No longer content with Internet filtering, many governments in the Middle East and around the world are using a variety of technological and offline strategies to go after online media and digital activists. In Tunisia, before and during the January 2011 protest movement that led to a change in government there, Internet service providers were apparently logging usernames and passwords to hack into and dismantle online organizing and information sharing among protesters. In early June 2011, Google reported a phishing attack targeted at military and human rights activists to gain access to their Gmail accounts. In Syria, a well organized effort known as the Syrian Electronic Army has been carrying out attacks to disable and compromise web sites that are critical of the Syrian regime. These stories are only a few selected from the set that have become public, and an unknown number of attacks go unnoticed and unreported. Many of these attacks are impossible to attribute to specific actors and may involve a mix of private sector and governmental actors, blurring the lines between cyber attacks and government surveillance. In such an environment, maintaining online security is a growing challenge.In this report we describe the results of a survey of 98 bloggers in the Middle East and North Africa (MENA) carried out in May 2011 in order to study bloggers' perceptions of online risk and the actions they take to address digital communications security, including both Internet and cell phone use. The survey was implemented in the wake of the Arab spring and documents a proliferation of online security problems among the respondents. In the survey, we address the respondents' perceptions of online risk, their knowledge of digital security practices, and their reported online security practices. The survey results indicate that there is much room for improving online security practices, even among this sample of respondents who are likely to have relatively high technical knowledge and experience

    Global Assessment of EC Mine Action Policy and Actions 2002-2004

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    The Anti-Personnel Landmine Regulation mandates an overall assessment of all EC mine action every three years. This report contains the first such assessment for the period 2002-2004. The total funding by all EC budget lines for 2002-2004 for mine action was about 116M, of which the horizontal mine action budget line was nearly 40% at 45M. The total for the same period for all EU mine action, including contributions by Member States, was about 410M, of which the dedicated budget line is just 11%. The overall assessment reviewed four areas: 1) how the APL Regulation was used to generate mine action strategy, 2) how the strategy was used to implement the multi-annual programme, 3) how projects were selected and contracted in order to achieve the programme objectives and 4) the evaluation and assessment processes used. It then provides a summary of the key findings and puts forward a series of recommendations. Data was collected from documents, databases and internet searches, interviews with staff in Brussels, telephone interviews with key organisation staff, questionnaires to delegations and project implementers, and three field missions (Azerbaijan, Bosnia and Herzegovina and Somalia)

    The classical limit of the time dependent Hartree-Fock equation. I. The Weyl symbol of the solution

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    We study the time evolution of the Weyl symbol of a solution of the time dependent Hartree Fock equation, assuming that for t=0, it has a Weyl symbol which is integrable in the phase space, such as all its derivatives. We prove that the solution has the same property for all t, and we give an asymptotic expansion, in L1 sense, of this Weyl symbol

    Exploring Russian Cyberspace: Digitally-Mediated Collective Action and the Networked Public Sphere

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    This paper summarizes the major findings of a three-year research project to investigate the Internet's impact on Russian politics, media and society. We employed multiple methods to study online activity: the mapping and study of the structure, communities and content of the blogosphere; an analogous mapping and study of Twitter; content analysis of different media sources using automated and human-based evaluation approaches; and a survey of bloggers; augmented by infrastructure mapping, interviews and background research. We find the emergence of a vibrant and diverse networked public sphere that constitutes an independent alternative to the more tightly controlled offline media and political space, as well as the growing use of digital platforms in social mobilization and civic action. Despite various indirect efforts to shape cyberspace into an environment that is friendlier towards the government, we find that the Russian Internet remains generally open and free, although the current degree of Internet freedom is in no way a prediction of the future of this contested space

    On the Corrections to Dashen's Theorem

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    The electromagnetic corrections to the masses of the pseudoscalar mesons π\pi and KK are considered. We calculate in chiral perturbation theory the contributions which arise from resonances within a photon loop at order O(e2mq)O(e^2 m_q). Within this approach we find rather moderate deviations to Dashen's theorem.Comment: 14 pages, sligthly enlarged version; a numerical error is corrected and the embedding of the figures is improved. The complete paper, including figures, is also available via anonymous ftp at ftp://www-ttp.physik.uni-karlsruhe.de/ , or via www at http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/preprints/; to be published in Phys.Rev.

    Resonance Contributions to the Electromagnetic Low Energy Constants of Chiral Perturbation Theory

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    The effective chiral Lagrangian of the strong and electromagnetic interactions of the pseudoscalar mesons at low energies depends on a set of low energy constants. We determine the contributions to the electromagnetic coupling constants at order O(e2p2)O(e^2 p^2), which arise from resonances within a photon loop. We give some implications of our results, in particular we discuss in detail the effects on the corrections to Dashen's theorem.Comment: LaTex (uses epsfig.sty), 35 pages including 3 Postscript figures. The complete paper is also available via anonymous ftp at ftp://www-ttp.physik.uni-karlsruhe.de/ , or via www at http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/preprints/ ; slightly enlarged version. Accepted for publication in Nucl. Phys.

    Internet Monitor 2014: Reflections on the Digital World: Platforms, Policy, Privacy, and Public Discourse

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    This publication is the second annual report of the Internet Monitor project at the Berkman Center for Internet & Society at Harvard University. As with the inaugural report, this year's edition is a collaborative effort of the extended Berkman community. Internet Monitor 2014: Reflections on the Digital World includes nearly three dozen contributions from friends and colleagues around the world that highlight and discuss some of the most compelling events and trends in the digitally networked environment over the past year.The result, intended for a general interest audience, brings together reflection and analysis on a broad range of issues and regions—from an examination of Europe's "right to be forgotten" to a review of the current state of mobile security to an exploration of a new wave of movements attempting to counter hate speech online—and offers it up for debate and discussion. Our goal remains not to provide a definitive assessment of the "state of the Internet" but rather to provide a rich compendium of commentary on the year's developments with respect to the online space.Last year's report examined the dynamics of Internet controls and online activity through the actions of government, corporations, and civil society. We focus this year on the interplay between technological platforms and policy; growing tensions between protecting personal privacy and using big data for social good; the implications of digital communications tools for public discourse and collective action; and current debates around the future of Internet governance.The report reflects the diversity of ideas and input the Internet Monitor project seeks to invite. Some of the contributions are descriptive; others prescriptive. Some contain purely factual observations; others offer personal opinion. In addition to those in traditional essay format, contributions this year include a speculative fiction story exploring what our increasingly data-driven world might bring, a selection of "visual thinking" illustrations that accompany a number of essays, a "Year in Review" timeline that highlights many of the year's most fascinating Internet-related news stories (and an interactive version of which is available at thenetmonitor.org), and a slightly tongue-in-cheek "By the Numbers" section that offers a look at the year's important digital statistics. We believe that each contribution offers insights, and hope they provoke further reflection, conversation, and debate in both offline and online settings around the globe

    Refixation stability in shoulder hemiarthroplasty in case of four-part proximal humeral fracture

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    Primary stability of refixated fractures in case of shoulder hemiarthroplasty is a prerequisite to restore physiological glenohumeral joint function. Clinical observations often show a secondary dislocation and subsequent resorption of the bony anchor points like the greater and lesser tuberosity at the rotator cuff tendons. This failed integration leads to impaired glenohumeral load transmission and subsequent reduction of mobility. As a consequence, the optimisation of refixation methods is crucial for a better clinical outcome. To prove the stability of refixation techniques, a Finite Element fracture model was built. Resulting stresses at the bone surface and fragment migration relative to the prosthesis shaft were studied. The results of the calculations show that the isolated tuberosities show unstressed bone regions compared to the intact model. This circumstance may explain the clinically detected bone resorption due to the absence of mechanical stimuli. Furthermore, a cable guidance through lateral holes in the middle part of the proximal prosthesis results in a lower fragment displacement than a circumferential fixation method surrounding the entire proximal bon

    Pouvons-nous réduire la dose d’azote après un retour de prairie?

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    Affiche présentée dans le cadre du Colloque de l'ARC, «Des racines et des ailes pour la recherche collégiale», dans le cadre du 85e Congrès de l’Acfas, Université McGill, Montréal, les 8 et 9 mai 2017.Au Québec, les émissions de gaz à effet de serre (GES) d’origine agricole représentent près de 8 % des émissions totales. Environ 40 % des émissions agricoles découle de l’usage des engrais minéraux et des engrais de ferme. Tout apport excédentaire d’engrais azoté dans les cultures se traduit par des émissions supplémentaires d’oxyde nitreux (N2O), un puissant gaz à effet de serre qui contribue aux émissions de GES. Plusieurs études ont démontré que la culture de maïs n’avait pas besoin d’apports importants d’azote en postlevée, après des retours de prairie. En collaboration avec des producteurs agricoles, 16 sites d’essais de fertilisation azotée ont été implantés sur des retours de prairie ayant reçu des engrais de ferme. Les traitements consistaient à apporter 4 doses d’azote minéral (0, 40, 80 et 120 kg N/ha). La teneur en nitrates du sol ainsi que les rendements à la récolte ont été évalués. La teneur en nitrates a confirmé l’effet significatif de la prairie et des engrais de ferme sur la teneur en azote disponible pour le maïs. L’apport d’azote minéral n’a pas eu d’effet significatif sur les rendements en azote, à l’exception d’un site. Le maïs cultivé sur un retour de prairie ne nécessite pas un ajout d’engrais minéral. Éliminer l’apport d’azote réduit tant les émissions de GES que les dépenses en engrais pour les producteurs
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