24,205 research outputs found
A Reanalysis of Small Scale Velocity Dispersion in the CfA1 Survey
The velocity dispersion of galaxies on scales of Mpc,
, may be estimated from the anisotropy of the galaxy-galaxy
correlation function in redshift space. We present a reanalysis of the CfA1
survey, correct an error in the original analysis of Davis and Peebles (1983),
and find that is extremely sensitive to the details of how
corrections for infall into the Virgo cluster are applied. We conclude that a
robust value of cannot be obtained from this survey. We also
discuss results from other redshift surveys, including the effect of removing
clusters.Comment: 12 pages, uuencoded(latex file + 2 Postscript figures), uses aas
macro
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A Service Evaluation of the use of Mealtime Advice Mats within an Adult Learning Disability Service
This study aimed to gather the views of residential support staff and multidisciplinary team members (MDT) in order to evaluate the effectiveness of the current mealtime advice mats. It aimed to use the information to plan improvements to the mats themselves or their provision. Methods: This service evaluation of a NHS Learning Disability team was granted approval by the local audit and development committee and registered so with City, University of London in partial fulfilment of an MSc in SLT. Consenting participants (42: 21 paid support staff, 21 MDT professionals) answered specifically created questionnaires. Areas explored included; frequency of mat use, adherence with mat guidelines, knowledge of the potential consequences of dysphagia and the format and design of the mats. The results were analysed using descriptive statistics and review of the free text comments. Results: Results indicated high levels of awareness of mealtime mats and reported use by support staff. The MDT had less awareness and reported reduced use of the mats by themselves and support staff. Support and MDT staff shared differing facilitators and barriers for adherence to mealtime mat guidelines. The current format was viewed positively with differing views on potential improvements e.g. increased picture recommended by MDT but not support staff. There was general awareness of many consequences of dysphagia but not all, with the MDT less aware. Conclusion: This study’s findings contribute to the limited literature on dysphagia recommendations for people with LD. Implications for service development, improvements to mats and future research avenues are discussed
Multiple wavemode scanning for near and far-side defect characterisation
The combination of ultrasonic inspections using different wavemodes can give more information than is available with single mode inspection. In this work, the response of shear and Rayleigh waves to surface-breaking defects propagating on the near-side and far-side of a sample is investigated. The directivity of shear waves generated by a racetrack coil electromagnetic acoustic transducer (EMAT) is identified and used to set an ideal separation for a pair of transmit-receive EMATs. Defects are indicated by a reduction in the transmitted Rayleigh wave amplitude, and by blocking of the shear wave. Used together, these can identify features in the bulk wave behaviour which are due to near-face surface-breaking defects, and give a full picture of both surfaces. By using a combination of the two wavemodes, the angle of propagation and length of any near-side defects can additionally be identified. A scanning method for samples is proposed
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The extent of community and public support available to families caring for orphans in Malawi.
There are an estimated 15 million AIDS orphans worldwide. Families play an important role in safeguarding orphans, but they may be increasingly compromised by the HIV/AIDS epidemic. The international aid community has recognized the need to help families continue caring for orphaned children by strengthening their safety nets. Before we build new structures, however, we need to know the extent to which community and public safety nets already provide support to families with orphans. To address this gap, we analyzed nationally representative data from 27,495 children in the 2004-2005 Malawi Integrated Household Survey. We found that communities commonly assisted orphan households through private transfers; organized responses to the orphan crisis were far less frequent. Friends and relatives provided assistance to over 75% of orphan households through private gifts, but the value of such support was relatively low. Over 40% of orphans lived in a community with support groups for the chronically ill and approximately a third of these communities provided services specifically for orphans and other vulnerable children. Public programs, which form a final safety net for vulnerable households, were more widespread. Free/subsidized agricultural inputs and food were the most commonly used public safety nets by children's households in the past year (44 and 13%, respectively), and households with orphans were more likely to be beneficiaries. Malawi is poised to drastically expand safety nets to orphans and their families, and these findings provide an important foundation for this process
Lamb wave near field enhancements for surface breaking defects in plates
Near field surface wave ultrasonic enhancements have previously been used to detect surface breaking defects in thick samples using Rayleigh waves. Here, we present analogous surface wave enhancements for Lamb waves propagating in plates. By tracking frequency intensities in selected regions of time-frequency representations, we observe frequency enhancement in the near field, due to constructive interference of the incident wave mode with those reflected and mode converted at the defect. This is explained using two test models; a square based notch and an opening crack, which are used to predict the contribution to the out-of-plane displacement from the reflected and mode converted waves. This method has the potential to provide a reliable method for the near field identification and characterisation of surface breaking defects in plates
Investigating the Magnitude and Range of the Urban Heat Island within Gettysburg, Pennsylvania
Cities experience UHIs due to the thermal properties (albedo, thermal emittance, radiative flux, and heat capacity) of human-made substances and urban geometry. This study investigated the existence of an urban heat island (UHI) in Gettysburg, Pennsylvania. The goal of this project was to assess whether a small-scale city like Gettysburg demonstrates an UHI effect and, if present, the extent and magnitude of the UHI. We hypothesized that (1) temperatures within the city are significantly higher than the surrounding area, (2) the magnitude of the UHI will diminish as distance from the city center increases, and (3) the UHI will not extend further than 0.5 miles outside the city center. Air temperatures were collected using digital thermometers over four weeks along two different transects that each extended one mile from the center square of Gettysburg. Our results show that Gettysburg, despite its small size, has an UHI. A linear regression model shows that there is a strong correlation between temperature and distance from the center square. The magnitude of the UHI lessens with increasing distance from the center of town. The first two hypotheses were supported while the hypothesis that the UHI will be localized was not. Statistically analyses show that the temperature change remains significant past 0.5 miles. The results of this study demonstrate that even a small-scale city like Gettysburg create a UHI
Interpretation at the controller's edge: designing graphical user interfaces for the digital publication of the excavations at Gabii (Italy)
This paper discusses the authors’ approach to designing an interface for the Gabii Project’s digital volumes that attempts to fuse elements of traditional synthetic publications and site reports with rich digital datasets. Archaeology, and classical archaeology in particular, has long engaged with questions of the formation and lived experience of towns and cities. Such studies might draw on evidence of local topography, the arrangement of the built environment, and the placement of architectural details, monuments and inscriptions (e.g. Johnson and Millett 2012). Fundamental to the continued development of these studies is the growing body of evidence emerging from new excavations. Digital techniques for recording evidence “on the ground,” notably SFM (structure from motion aka close range photogrammetry) for the creation of detailed 3D models and for scene-level modeling in 3D have advanced rapidly in recent years. These parallel developments have opened the door for approaches to the study of the creation and experience of urban space driven by a combination of scene-level reconstruction models (van Roode et al. 2012, Paliou et al. 2011, Paliou 2013) explicitly combined with detailed SFM or scanning based 3D models representing stratigraphic evidence. It is essential to understand the subtle but crucial impact of the design of the user interface on the interpretation of these models. In this paper we focus on the impact of design choices for the user interface, and make connections between design choices and the broader discourse in archaeological theory surrounding the practice of the creation and consumption of archaeological knowledge. As a case in point we take the prototype interface being developed within the Gabii Project for the publication of the Tincu House. In discussing our own evolving practices in engagement with the archaeological record created at Gabii, we highlight some of the challenges of undertaking theoretically-situated user interface design, and their implications for the publication and study of archaeological materials
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