7,199 research outputs found
Particle displacements in the elastic deformation of amorphous materials: local fluctuations vs. non-affine field
We study the local disorder in the deformation of amorphous materials by
decomposing the particle displacements into a continuous, inhomogeneous field
and the corresponding fluctuations. We compare these fields to the commonly
used non-affine displacements in an elastically deformed 2D Lennard-Jones
glass. Unlike the non-affine field, the fluctuations are very localized, and
exhibit a much smaller (and system size independent) correlation length, on the
order of a particle diameter, supporting the applicability of the notion of
local "defects" to such materials. We propose a scalar "noise" field to
characterize the fluctuations, as an additional field for extended continuum
models, e.g., to describe the localized irreversible events observed during
plastic deformation.Comment: Minor corrections to match the published versio
A complete analytical solution for the inverse instantaneous kinematics of a spherical-revolute-spherical (7R) redundant manipulator
Using a method based upon resolving joint velocities using reciprocal screw quantities, compact analytical expressions are generated for the inverse solution of the joint rates of a seven revolute (spherical-revolute-spherical) manipulator. The method uses a sequential decomposition of screw coordinates to identify reciprocal screw quantities used in the resolution of a particular joint rate solution, and also to identify a Jacobian null-space basis used for the direct solution of optimal joint rates. The results of the screw decomposition are used to study special configurations of the manipulator, generating expressions for the inverse velocity solution for all non-singular configurations of the manipulator, and identifying singular configurations and their characteristics. Two functions are therefore served: a new general method for the solution of the inverse velocity problem is presented; and complete analytical expressions are derived for the resolution of the joint rates of a seven degree of freedom manipulator useful for telerobotic and industrial robotic application
A study of the dynamics of rotating space stations with elastically connected counterweight and attached flexible appendages. Volume 1: Theory
The formulation of a mathematical model for predicting the dynamic behavior of rotating flexible space station configurations was conducted. The overall objectives of the study were: (1) to develop the theoretical techniques for determining the behavior of a realistically modeled rotating space station, (2) to provide a versatile computer program for the numerical analysis, and (3) to present practical concepts for experimental verification of the analytical results. The mathematical model and its associated computer program are described
Sex workers perspectives on strategies to reduce sexual exploitation and HIV risk: a qualitative study in Tijuana, Mexico.
Globally, female sex workers are a population at greatly elevated risk of HIV infection, and the reasons for and context of sex industry involvement have key implications for HIV risk and prevention. Evidence suggests that experiences of sexual exploitation (i.e., forced/coerced sex exchange) contribute to health-related harms. However, public health interventions that address HIV vulnerability and sexual exploitation are lacking. Therefore, the objective of this study was to elicit recommendations for interventions to prevent sexual exploitation and reduce HIV risk from current female sex workers with a history of sexual exploitation or youth sex work. From 2010-2011, we conducted in-depth interviews with sex workers (nâ=â31) in Tijuana, Mexico who reported having previously experienced sexual exploitation or youth sex work. Participants recommended that interventions aim to (1) reduce susceptibility to sexual exploitation by providing social support and peer-based education; (2) mitigate harms by improving access to HIV prevention resources and psychological support, and reducing gender-based violence; and (3) provide opportunities to exit the sex industry via vocational supports and improved access to effective drug treatment. Structural interventions incorporating these strategies are recommended to reduce susceptibility to sexual exploitation and enhance capacities to prevent HIV infection among marginalized women and girls in Mexico and across international settings
Domino: exploring mobile collaborative software adaptation
Social Proximity Applications (SPAs) are a promising new area for ubicomp software that exploits the everyday changes in the proximity of mobile users. While a number of applications facilitate simple file sharing between coâpresent users, this paper explores opportunities for recommending and sharing software between users. We describe an architecture that allows the recommendation of new system components from systems with similar histories of use. Software components and usage histories are exchanged between mobile users who are in proximity with each other. We apply this architecture in a mobile strategy game in which players adapt and upgrade their game using components from other players, progressing through the game through sharing tools and history. More broadly, we discuss the general application of this technique as well as the security and privacy challenges to such an approach
Error Prevention Scheme with Four Particles
It is shown that a simplified version of the error correction code recently
suggested by Shor exhibits manifestation of the quantum Zeno effect. Thus,
under certain conditions, protection of an unknown quantum state is achieved.
Error prevention procedures based on four-particle and two-particle encoding
are proposed and it is argued that they have feasible practical
implementations.Comment: 4 pages, RevTeX, references updated and improved protocol adde
Classification of Message Spreading in a Heterogeneous Social Network
Nowadays, social networks such as Twitter, Facebook and LinkedIn become
increasingly popular. In fact, they introduced new habits, new ways of
communication and they collect every day several information that have
different sources. Most existing research works fo-cus on the analysis of
homogeneous social networks, i.e. we have a single type of node and link in the
network. However, in the real world, social networks offer several types of
nodes and links. Hence, with a view to preserve as much information as
possible, it is important to consider so-cial networks as heterogeneous and
uncertain. The goal of our paper is to classify the social message based on its
spreading in the network and the theory of belief functions. The proposed
classifier interprets the spread of messages on the network, crossed paths and
types of links. We tested our classifier on a real word network that we
collected from Twitter, and our experiments show the performance of our belief
classifier
Establishing an international research collaborative for naturopathy: The International Research Consortium of Naturopathic Academic Clinics (IRCNAC)
© 2017 Elsevier Ltd Naturopathy is a system of healthcare through which practitioners apply core philosophies, theories and principles to integrate medical knowledge with natural treatment options. In recent years the naturopathic community has developed a stronger international coherence. Alongside this growing connectivity in the global naturopathic profession, there have been a number of calls for more systematic research attention to be devoted to naturopathy as a substantive research topic, as well as a need for the naturopathic profession to hone a culture of research and evidence-based practices and skillsets. Progress in this area has been made through the development of more pragmatic and whole systems naturopathic research. One aspect which is currently missing in the global naturopathic research landscape despite this growing pattern of practice-based, whole systems research is the application of international multicentre research projects. In response, we have established a research consortium for naturopathic academic clinics in four countries and across multiple world regions. This paper serves to overview the mission, scope and membership of the research consortium and explore some of the research designs and questions which it may support
International study into the use of intermittent hormone therapy in the treatment of carcinoma of the prostate : A meta-analysis of 1446 patients
OBJECTIVE: To review pooled phase II data to identify features of different regimens of intermittent hormone therapy (IHT), developed to reduce the morbidity of treating metastatic prostate cancer, and which carries a theoretical advantage of delaying the onset of androgen-independent prostate cancer, (AIPC) that are associated with success, highlighting features which require exploration with prospective trials to establish the best strategies for using this treatment. METHODS: Individual data were collated on 1446 patients with adequate information, from 10 phase II studies with >50 cases, identified through Pubmed. RESULTS: Univariate and multivariate Cox proportional hazard models were developed to predict treatment success with a high degree of statistical success. The prostate-specific antigen (PSA) nadir, the PSA threshold to restart treatment, and medication type and duration, were important predictors of outcome. CONCLUSIONS: The duration of biochemical remission after a period of HT is a durable early indicator of how rapidly AIPC and death will occur, and will make a useful endpoint in future trials to investigate the best ways to use IHT based on the important treatment cycling variables described above. Patients spent a mean of 39% of the time off treatment. The initial PSA level and PSA nadir allow the identification of patients with prostate cancer in whom it might be possible to avoid radical therapy.Peer reviewe
- âŠ