11,188 research outputs found
Scan rate converter for tape recording and playback of TV pictures
Magnetic tape recording and playback equipment converts television pictures, both black and white and color, from one scan rate to another. The equipment indexes color picture frames for retrieval electronically and can be used as a document storage and retrieval medium that is compatible with hard-copy printout machines
Ocean waves near Hurricane Josephine from SIR-B
Radar images of ocean surface waves near hurricane Josephine were acquired with the Shuttle Imaging Radar-B (SIR-B) system on October 12, 1984. Fast Fourier transform analyses of the images were performed along most of the 600-km image track. These data reveal the presence of at least two dominant wave systems which undergo significant spatial variations in wavelength and direction
Systematic review of brucellosis in the Middle East: disease frequency in ruminants and humans and risk factors for human infection
This paper considers the problem of finding global states incoming to a specified global state in a Boolean network, which may be useful for pre-processing of finding a sequence of control actions for a Boolean network and for identifying the basin of attraction for a given attractor, We show that this problem is NP-hard in general along with related theoretical results, On the other hand, we present algorithms that are much faster than the naive exhaustive search-based algorithm. ©2007 IEEE.link_to_subscribed_fulltex
Fermi Surface Reconstruction by Dynamic Magnetic Fluctuations
We demonstrate that nearly critical quantum magnetic fluctuations in strongly
correlated electron systems can change the Fermi surface topology and also lead
to spin charge separation (SCS) in two dimensions. To demonstrate these effects
we consider a small number of holes injected into the bilayer antiferromagnet.
The system has a quantum critical point (QCP) which separates magnetically
ordered and disordered phases. We demonstrate that in the physically
interesting regime there is a magnetically driven Lifshitz point (LP) inside
the magnetically disordered phase. At the LP the topology of the hole Fermi
surface is changed. We also demonstrate that in this regime the hole spin and
charge necessarily separate when approaching the QCP. The considered model
sheds light on generic problems concerning the physics of the cuprates.Comment: updated version, accepted to PR
Media Industries: History, Theory and Method
Media Industries: History, Theory, and Method outlnes the diverse ways that media indutries have been studied in the past and offers an innovate blueprint for future research and cristism. Contextualizing the current moment of unprecedented technological change, media convergence, and globalitation, the authors engange in crocs-disciplanary exploration from range of historical, critical and theoritical perspectives
Performance Analysis of Apollo Navigational Starter Routine
The focus of this project is to recreate and analyze the effectiveness of the original Apollo Starter Routine (ASR) which was used to generate the state vector of the Apollo spacecraft based on a series of radiometric observations. The original Apollo navigation software is unavailable in a modern programming language and the original coding has not been preserved. This necessitates its recreation using the original software documentation. Space Shuttle navigation software does not typically use the ASR or an algorithm like it since the Shuttle s state vector is easily deduced from GPS information or other sources. However, this tactic will be ineffective when trying to determine the state vector of a craft approaching, departing or in orbit around the Moon since the GPS network faces the surface of the Earth, not outer space. The recreation of the ASR from the original documentation is therefore vital as a simulation baseline for the navigation software under development for the Constellation program. The algorithms that make up the ASR will be extracted from the original documentation and adapted for and then implemented in a modern programming language; the majority of it will be coded in Matlab. The ASR s effectiveness will then be tested using simulated tracking data. The ability of the ASR to handle realistically noisy data and the accuracy with which it generates state vectors were analyzed. The ASR proved to be robust enough to process data with range and angle noise as large as 10,000 meters and 10(exp -6) radians together and 300,000 meters and 5x10(exp -4) radians separately at Lunar distances. The ASR was able to handle marginally more noise at distances closer to the Earth where the angle noise was less significant. The ASR is capable of effectively processing 40-80 data points gathered at a rate of one per 20 seconds at close Earth orbit and up to 28-40 data points gathered at a rate of one per minute at distant Earth orbit and Lunar orbit
Who will use pre-exposure prophylaxis (PrEP) and why?: Understanding PrEP awareness and acceptability amongst men who have sex with men in the UK – a mixed methods study
Background:
Recent clinical trials suggest that pre-exposure prophylaxis (PrEP) may reduce HIV transmission by up to 86% for men who have sex with men (MSM), whilst relatively high levels of PrEP acceptability have been reported to date. This study examines PrEP awareness amongst sub-groups of MSM communities and acceptability amongst MSM in a low prevalence region (Scotland, UK), using a mixed methods design.
Methods:
Quantitative surveys of n = 690 MSM recruited online via social and sociosexual media were analysed using descriptive statistics and multivariate logistic regression. In addition, n = 10 in-depth qualitative interviews with MSM were analysed thematically.
Results:
Under one third (29.7%) of MSM had heard of PrEP, with awareness related to living in large cities, degree level education, commercial gay scene use and reporting an HIV test in the last year. Just under half of participants (47.8%) were likely to use PrEP if it were available but there was no relationship between PrEP acceptability and previous PrEP awareness. Younger men (18–25 years) and those who report higher risk UAI were significantly more likely to say they would use PrEP. Qualitative data described specific PrEP scenarios, illustrating how risk, patterns of sexual practice and social relationships could affect motivation for and nature of PrEP use.
Conclusion:
These findings suggest substantial interest PrEP amongst MSM reporting HIV risk behaviours in Scotland. Given the Proud results, there is a strong case to investigate PrEP implementation within the UK. However, it appears that disparities in awareness have already emerged along traditional indicators of inequality. Our research identifies the need for comprehensive support when PrEP is introduced, including a key online component, to ensure equity of awareness across diverse MSM communities (e.g. by geography, education, gay scene use and HIV proximity), as well as to responding to the diverse informational and sexual health needs of all MSM communities
Leading the evaluation of institutional online learning environments for quality enhancement in times of change
This paper reports on findings from a nationally funded project which aims to design and implement a quality management framework for online learning environments (OLEs). Evaluation is a key component of any quality management system and it is this aspect of the framework that is the focus of this paper. In developing the framework initial focus groups were conducted at the five participating institutions. These revealed that, although regarded as important, there did not appear to be a shared understanding of the nature and purpose of evaluation. A second series of focus groups revealed there were multiple perspectives arising from those with a vested interest in online learning. These perspectives will be outlined. Overall, how evaluation was undertaken was highly variable within and across the five institutions reflecting where they were at in relation to the development of their OLE
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