14,028 research outputs found
Spacelab data analysis and interactive control study
The study consisted of two main tasks, a series of interviews of Spacelab users and a survey of data processing and display equipment. Findings from the user interviews on questions of interactive control, downlink data formats, and Spacelab computer software development are presented. Equipment for quick look processing and display of scientific data in the Spacelab Payload Operations Control Center (POCC) was surveyed. Results of this survey effort are discussed in detail, along with recommendations for NASA development of several specific display systems which meet common requirements of many Spacelab experiments
X-ray Development of the Classical Nova V2672 Ophiuchi with Suzaku
We report the Suzaku detection of a rapid flare-like X-ray flux amplification
early in the development of the classical nova V2672 Ophiuchi. Two
target-of-opportunity ~25 ks X-ray observations were made 12 and 22 days after
the outburst. The flux amplification was found in the latter half of day 12.
Time-sliced spectra are characterized by a growing supersoft excess with
edge-like structures and a relatively stable optically-thin thermal component
with Ka emission lines from highly ionized Si. The observed spectral evolution
is consistent with a model that has a time development of circumstellar
absorption, for which we obtain the decline rate of ~10-40 % in a time scale of
0.2 d on day 12. Such a rapid drop of absorption and short-term flux
variability on day 12 suggest inhomogeneous ejecta with dense blobs/holes in
the line of sight. Then on day 22 the fluxes of both supersoft and thin-thermal
plasma components become significantly fainter. Based on the serendipitous
results we discuss the nature of this source in the context of both short- and
long-term X-ray behavior.Comment: To appear in PASJ; 9 pages, 5 figures, 2 table
Hearing new voices: re-viewing youth justice policy through practitioners’ relationships with young people
The relationship between young people and practitioners is the centre-piece of youth justice provision, yet little research-based knowledge has accumulated on its minutiae. After reviewing reforms affecting professional discretion, the paper draws on the concepts of dyadic relationships and praxis to reinvigorate a research agenda aimed at delineating a more nuanced understanding of practice relationships. Drawing on practice wisdom from across related social work fields, we argue that centralizing the practitioner-young person relationship remains the key to successful practice and thus needs greater, more detailed research attention. These claims are supported with a number of pilot interviews with youth justice workers about successful interventions that complement and extend related studies. The paper concludes with suggestions for research to enable joint activity between young people and practitioners to ‘rethink’ youth justice
Host-Parasite Co-evolution and Optimal Mutation Rates for Semi-conservative Quasispecies
In this paper, we extend a model of host-parasite co-evolution to incorporate
the semi-conservative nature of DNA replication for both the host and the
parasite. We find that the optimal mutation rate for the semi-conservative and
conservative hosts converge for realistic genome lengths, thus maintaining the
admirable agreement between theory and experiment found previously for the
conservative model and justifying the conservative approximation in some cases.
We demonstrate that, while the optimal mutation rate for a conservative and
semi-conservative parasite interacting with a given immune system is similar to
that of a conservative parasite, the properties away from this optimum differ
significantly. We suspect that this difference, coupled with the requirement
that a parasite optimize survival in a range of viable hosts, may help explain
why semi-conservative viruses are known to have significantly lower mutation
rates than their conservative counterparts
A survey of interstellar HI from L alpha absorption measurements 2
The Copernicus satellite surveyed the spectral region near L alpha to obtain column densities of interstellar HI toward 100 stars. The distance to 10 stars exceeds 2 kpc and 34 stars lie beyond 1 kpc. Stars with color excess E(B-V) up to 0.5 mag are observed. The value of the mean ratio of total neutral hydrogen to color excess was found to equal 5.8 x 10 to the 21st power atoms per (sq cm x mag). For stars with accurate E(B-V), the deviations from this mean are generally less than a factor of 1.5. A notable exception is the dark cloud star, rho Oph. A reduction in visual reddening efficiency for the grains that are larger than normal in the rho Oph dark cloud probably explains this result. The conversion of atomic hydrogen into molecular form in dense clouds was observed in the gas to E(B-V) correlation plots. The best estimate for the mean total gas density for clouds and the intercloud medium, as a whole, in the solar neighborhood and in the plane of the galaxy is 1.15 atoms per cu. cm; those for the atomic gas and molecular gas alone are 0.86 atoms per cu cm and 0.143 molecules per cu cm respectively. For the intercloud medium, where molecular hydrogen is a negligible fraction of the total gas, atomic gas density was found to equal 0.16 atoms per cu cm with a Gaussian scale height perpendicular to the plane of about 350 pc, as derived from high latitude stars
On the 3-D structure and dissipation of reconnection-driven flow-bursts
The structure of magnetic reconnection-driven outflows and their dissipation
are explored with large-scale, 3-D particle-in-cell (PIC) simulations. Outflow
jets resulting from 3-D reconnection with a finite length x-line form fronts as
they propagate into the downstream medium. A large pressure increase ahead of
this ``reconnection jet front'' (RJF), due to reflected and transmitted ions,
slows the front so that its velocity is well below the velocity of the ambient
ions in the core of the jet. As a result, the RJF slows and diverts the
high-speed flow into the direction perpendicular to the reconnection plane. The
consequence is that the RJF acts as a thermalization site for the ion bulk flow
and contributes significantly to the dissipation of magnetic energy during
reconnection even though the outflow jet is subsonic. This behavior has no
counterpart in 2-D reconnection. A simple analytic model predicts the front
velocity and the fraction of the ion bulk flow energy that is dissipated
Birth of the Pipes: The Organ from its Beginnings through the Baroque Era
The purpose of this presentation is to survey the development of the organ, which is one of the most magnificent and impressive musical instruments known to man. The main objective is also to explain how and why the organ developed the way that it did. Further, the presentation will attempt to answer the following questions: what deficiencies in the performance of early organs were organ builders trying to improve on, what differences in sound did they want new organs to be able to produce, and how did the needs and preferences of organists influence changes in organ design? The majority of the research for this presentation centers on the scholarly contributions of C.A. Edwards, C. F. Abdy Williams, and Willi Apel. Specifically, the focus is placed on the designs and construction of a wide variety of organs. Hopefully, this presentation will result in a clear understanding of the distinctions between these instruments and the related pros and cons
A Study of digital communications between universities and students
This study examined the digital and social media communication practices of nine urban universities including UMSL and compared those to known corporate best practices.
The purpose of this study was to (1) research how these universities are using social/digital communications to engage with students and prospective students; (2) compare the executional tactics of universities to corporate best practices; (3) determine if by applying corporate best practices universities reap the same benefits as corporate in terms of higher engagement rates with their customers; and (4) determine if a correlation exists between a university’s Forbes ranking and its use of social media communications best practices.
This research employed a case study and correlational analytical approach. All content on Facebook and Twitter for the nine universities under study was examined for a 4-week evaluation period. Adherence to social and digital media corporate best practices were observed and noted. Metrics were created. These metrics were then correlated with overall engagement rates on the various social media platforms.
The results of this study did show that those universities better at applying corporate best practices did see higher engagement rates with statistical significance. This indicates that best practices as determined by corporations for engaging with customers and potential customers also apply for universities in dealing with students.
Additionally, this study sought to understand issues that may hinder a university from being able to quickly adopt to the technological needs of students and the platforms they use for communications. This was done via an extensive review of the literature and various industry journals. There were found to be many reasons why a university may be incapable of implementing cutting edge communication platforms quickly including the fact that universities (1) may be slower in adoption of technology (2) must adhere to FERPA rules and regulations (3) have difficulty in operating strategically (4) are known to be very “siloed” or compartmentalized in structure (5) have limited resources that cannot be easily redeployed as needed, and (6) are confused about their customers
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