786 research outputs found

    Towards a Holistic CAD Platform for Nanotechnologies

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    Silicon-based CMOS technologies are predicted to reach their ultimate limits by the middle of the next decade. Research on nanotechnologies is actively conducted, in a world-wide effort to develop new technologies able to maintain the Moore's law. They promise revolutionizing the computing systems by integrating tremendous numbers of devices at low cost. These trends will have a profound impact on the architectures of computing systems and will require a new paradigm of CAD. The paper presents a work in progress on this direction. It is aimed at fitting requirements and constraints of nanotechnologies, in an effort to achieve efficient use of the huge computing power promised by them. To achieve this goal we are developing CAD tools able to exploit efficiently these huge computing capabilities promised by nanotechnologies in the domain of simulation of complex systems composed by huge numbers of relatively simple elements.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

    Alexandra Kollontai and three Swedish female physicians – friendly relationships around the Soviet ambassador in Stockholm 1930–1945

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    Alexandra Kollontai was the Soviet ambassador to Sweden in the years 1930 to 1945. In Sweden she gained many friends in the peace- and women’s movement and among these were several female physicians. This article describes and investigates the friendships between Swedish female physicians and Alexandra Kollontai. The three physicians focused on are Ada Nilsson (1872–1964), Andrea Andreen (1888–1972) and Nanna Svartz (1890–1986). It is found that Kollontai and the physicians became proper friends, although initial contacts between them had political or medical causes

    Categorical Foundation of Quantum Mechanics and String Theory

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    The unification of Quantum Mechanics and General Relativity remains the primary goal of Theoretical Physics, with string theory appearing as the only plausible unifying scheme. In the present work, in a search of the conceptual foundations of string theory, we analyze the relational logic developed by C. S. Peirce in the late nineteenth century. The Peircean logic has the mathematical structure of a category with the relation RijR_{ij} among two individual terms SiS_i and SjS_j, serving as an arrow (or morphism). We introduce a realization of the corresponding categorical algebra of compositions, which naturally gives rise to the fundamental quantum laws, thus indicating category theory as the foundation of Quantum Mechanics. The same relational algebra generates a number of group structures, among them WW_{\infty}. The group WW_{\infty} is embodied and realized by the matrix models, themselves closely linked with string theory. It is suggested that relational logic and in general category theory may provide a new paradigm, within which to develop modern physical theories.Comment: To appear in International Journal of Modern Physics

    Social Needs Resource Connections: A Systematic Review of Barriers, Facilitators, and Evaluation

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    Healthcare organizations increasingly are screening patients for social needs (e.g., food, housing) and referring them to community resources. This systematic mixed studies review assesses how studies evaluate social needs resource connections and identifies patient- and caregiver-reported factors that may inhibit or facilitate resource connections

    Single event effects in static and dynamic registers in a 0.25μm0.25-\mu-m CMOS technology

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    We have studied single event effects in static and dynamic registers designed in a quarter micron CMOS process. In our design, we systematically used guardrings and enclosed (edgeless) transistor geometry to improve the total dose tolerance. This design technique improved both the SEL and SEU sensitivity of the circuits. Using SPICE simulations, the measured smooth transition of the cross-section curve between LET threshold and saturation has been traced to the presence of four different upset modes, each corresponding to a different critical charge and sensitive area. A new architecture to protect the content of storage cells has been developed, and a threshold LET around 89 MeV cm/sup 2/ mg/sup -1/ has been measured for this cell at a power supply voltage of 2 V

    Neutrino tomography - Learning about the Earth's interior using the propagation of neutrinos

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    Because the propagation of neutrinos is affected by the presence of Earth matter, it opens new possibilities to probe the Earth's interior. Different approaches range from techniques based upon the interaction of high energy (above TeV) neutrinos with Earth matter, to methods using the MSW effect on the neutrino oscillations of low energy (MeV to GeV) neutrinos. In principle, neutrinos from many different sources (sun, atmosphere, supernovae, beams etc.) can be used. In this talk, we summarize and compare different approaches with an emphasis on more recent developments. In addition, we point out other geophysical aspects relevant for neutrino oscillations.Comment: 22 pages, 9 figures. Proceedings of ``Neutrino sciences 2005: Neutrino geophysics'', December 14-16, 2005, Honolulu, USA. Minor changes, some references added. Final version to appear in Earth, Moon, and Planet

    Development of the AASPIRE web accessibility guidelines for autistic web users

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    Websites figure predominantly in everyday life. However, many websites remain inaccessible to autistic people, and existing efforts to improve accessibility are in early stages, do not directly include autistic users in their development, or have not been empirically evaluated. The Academic Autism Spectrum Partnership in Research and Education (AASPIRE) used a community-based participatory research approach to create a website to improve health care access for autistic adults. We used the creation of that website as a “living laboratory” to develop the AASPIRE Web Accessibility Guidelines for Autistic Web Users. Our guidelines are grounded in accessibility theory, had autistic end-user involvement at all stages, and were empirically evaluated through a usability study and evaluation surveys. We incorporated what we learned into the design of the website, and compiled the accessibility information into a set of guidelines. The guidelines offer recommendations for increasing the physical, intellectual, and social acceptability of websites for use by autistic adults. In the evaluation of the website by 170 autistic end users, nearly all indicated it was easy to use (97%), easy to understand (95%), important (97%), and useful (96%). Ninety-two percent would recommend it to a friend, and 95% would recommend it to a health care provider. There were no significant associations between usability or understandability and education level, receipt of help using the site, browser type (e.g., IE or Safari), or device type (e.g., PC or tablet). We recommend using the guidelines to improve website accessibility for autistic Internet users

    Second Order Perturbations of a Macroscopic String; Covariant Approach

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    Using a world-sheet covariant formalism, we derive the equations of motion for second order perturbations of a generic macroscopic string, thus generalizing previous results for first order perturbations. We give the explicit results for the first and second order perturbations of a contracting near-circular string; these results are relevant for the understanding of the possible outcome when a cosmic string contracts under its own tension, as discussed in a series of papers by Vilenkin and Garriga. In particular, second order perturbations are necessaary for a consistent computation of the energy. We also quantize the perturbations and derive the mass-formula up to second order in perturbations for an observer using world-sheet time τ\tau . The high frequency modes give the standard Minkowski result while, interestingly enough, the Hamiltonian turns out to be non-diagonal in oscillators for low-frequency modes. Using an alternative definition of the vacuum, it is possible to diagonalize the Hamiltonian, and the standard string mass-spectrum appears for all frequencies. We finally discuss how our results are also relevant for the problems concerning string-spreading near a black hole horizon, as originally discussed by Susskind.Comment: New discussion about the quantum mass-spectrum in chapter

    String Tension and the Generation of the Conformal Anomaly

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    The origin of the string conformal anomaly is studied in detail. We use a reformulated string Lagrangian which allows to consider the string tension T0T_{0} as a small perturbation. The expansion parameter is the worldsheet speed of light c, which is proportional to T0T_{0} . We examine carefully the interplay between a null (tensionless) string and a tensionful string which includes orders c2 c^{2} and higher. The conformal algebra generated by the constraints is considered. At the quantum level the normal ordering provides a central charge proportional to c2 c^{2} . Thus it is clear that quantum null strings respect conformal invariance and it is the string tension which generates the conformal anomaly.Comment: More references are included. Final version, to appear in Phys.Rev.D. 6 pages, LaTex, no figure

    The Association between Emergency Department Resources and Diagnosis of Intimate Partner Violence

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    Objective: There is little information about which intimate partner violence (IPV) policies and services assist in the identification of IPV in the emergency department (ED). The objective of this study was to examine the association between a variety of resources and documented IPV diagnoses. Methods: Using billing data assembled from 21 Oregon EDs from 2001 to 2005, we identified patients assigned a discharge diagnosis of IPV. We then surveyed ED directors and nurse managers to gain information about IPV-related policies and services offered by participating hospitals. We combined billing data, survey results and hospital-level variables. Multivariate analysis assessed the likelihood of receiving a diagnosis of IPV depending on the policies and services available. Results: In 754,597 adult female ED visits, IPV was diagnosed 1,929 times. Mandatory IPV screening and victim advocates were the most commonly available IPV resources. The diagnosis of IPV was independently associated with the use of a standardized intervention checklist (OR 1.71, 95% CI 1.04-2.82). Public displays regarding IPV were negatively associated with IPV diagnosis (OR 0.56, 95% CI 0.35-0.88). Conclusions: IPV remains a rare documented diagnosis. Most common hospital-level resources did not demonstrate an association with IPV diagnoses; however, a standardized intervention checklist may play a role in clinicians\u27 likelihood diagnosing IPV
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