3,667 research outputs found
The pulsation spectrum of VX Hydrae
We present the results of a two-year, multisite observing campaign
investigating the high-amplitude delta Scuti star VX Hydrae during the 2006 and
2007 observing seasons. The final data set consists of nearly 8500 V-band
observations spanning HJD 2453763.6 to 2454212.7 (2006 January 28 to 2007 April
22). Separate analyses of the two individual seasons of data yield 25
confidently-detected frequencies common to both data sets, of which two are
pulsation modes, and the remaining 23 are Fourier harmonics or beat frequencies
of these two modes. The 2006 data set had five additional frequencies with
amplitudes less than 1.5 mmag, and the 2007 data had one additional frequency.
Analysis of the full 2006-2007 data set yields 22 of the 25 frequencies found
in the individual seasons of data. There are no significant peaks in the
spectrum other than these between 0 and 60 c/d. The frequencies of the two main
pulsation modes derived from the 2006 and 2007 observing seasons individually
do not differ at the level of 3-sigma, and thus we find no conclusive evidence
for period change over the span of these observations. However, the amplitude
of f(1) = 5.7898 c/d changed significantly between the two seasons, while the
amplitude of f(0) = 4.4765 c/d remained constant; amplitudes of the Fourier
harmonics and beat frequencies of f(1) also changed. Similar behavior was seen
in the 1950s, and it is clear that VX Hydrae undergoes significant amplitude
changes over time.Comment: 14 pages, 5 figures, published in Publications of the Astronomical
Society of the Pacific, v.121, p.1076 (October 2009
What Explains the Incidence of the Use of a Common Sediment Control on Lots with Houses Under Construction?
To analyze compliance with one aspect of the regulation of stormwater discharge, we estimate a random-utility model of the probability that a builder uses a silt fence to control sediments on a lot with a house under construction in an urbanizing county of South Carolina. The probability increases if the builder is responsible to the subdivision’s developer or if a homeowners association exists. The probability also increases as the cost to install a silt fence decreases or the number of houses under construction per built house in a subdivision increases. The results can help county officials target inspection to improve compliance.compliance with regulation, erosion and sediment control, filter fabric, management of stormwater runoff, random-utility model, silt fence, storm water pollution prevention plan, Agribusiness, Community/Rural/Urban Development, Demand and Price Analysis, Environmental Economics and Policy, Industrial Organization, Land Economics/Use, Q01, Q24, Q53, Q58,
Reporting of Sex Specific Outcomes in High Impact Orthopedic Journals
Background: There are known biologic differences between men and women that affect all aspects of health and disease, including in orthopedics. Hormonal regulation influences bone density, tissue structure, joint laxity, and muscle mass. Differences in anatomy and neuromuscular control have also been identified. While previous studies on disease incidences have shown certain conditions are more common in one sex (e.g., osteoarthritis in women), it is not routine practice to evaluate or publish outcomes based on sex.
Objectives: To evaluate the frequency with which papers in orthopedic journals published sex-specific outcomes with regard to knee osteoarthritis and rotator cuff pathology.
Methods: Four high-impact orthopedic journals were reviewed: Journal of Bone and Joint Surgery (JBJS), Clinical Orthopedics and Related Research (CORR), American Journal of Sports Medicine (AJSM), and Journal of Arthroplasty (JOA). JBJS and CORR were reviewed for rotator cuff and knee osteoarthritis. AJSM was reviewed for rotator cuff, while JOA was reviewed for knee osteoarthritis. 100 articles from each journal were reviewed. If there was any further analysis of sex beyond the statement of how many men and women were included in each group, a study was designated as successfully reporting sexspecific outcomes.
Results: 24-29% of rotator cuff articles reported on sex-specific outcomes. Sex specific outcomes were reported in 32-40% of knee osteoarthritis publications. Comparing rotator cuff to knee osteoarthritis articles, there was a trend toward more publications with sex-specific outcomes in knee osteoarthritis, however, this was not statistically significant (p = 0.0562). JBJS publishes significantly more articles reporting sex specific outcomes regarding knee osteoarthritis than rotator cuff (p= 0.0156).
Conclusions: Sex-specific outcomes are not widely reported in high-impact orthopedic journals. Sexspecific outcomes are reported more often in knee osteoarthritis where there are already well-known sexbased differences. To improve care, sex-specific outcomes should be reported across all orthopedic conditions.https://jdc.jefferson.edu/sexandgenderhealth/1028/thumbnail.jp
Comment on "X-ray resonant scattering studies of orbital and charge ordering in Pr1-xCaxMnO3"
In a recent published paper [Phys. Rev. B 64, 195133 (2001)], Zimmermann et
al. present a systematic x-ray scattering study of charge and orbital ordering
phenomena in the Pr1-xCaxMnO3 series with x= 0.25, 0.4 and 0.5. They propose
that for Ca concentrations x=0.4 and 0.5, the appearance of (0, k+1/2, 0)
reflections are originated by the orbital ordering of the eg electrons in the
a-b plane while the (0, 2k+1, 0) reflections are due to the charge ordering
among the Mn3+ and Mn4+ ions. Moreover, for small Ca concentrations (x<0.3),
the orbital ordering is only considered and it occurs at (0, k, 0) reflections.
A rigorous analysis of all these resonance reflections will show the inadequacy
of the charge-orbital model proposed to explain the experimental results. In
addition, this charge-orbital model is highly inconsistent with the electronic
balance. On the contrary, these reflections can be easily understood as arising
from the anisotropy of charge distribution induced by the presence of local
distortions, i.e. due to a structural phase transition.Comment: 10 pages, 2 figures.To be published Phys. Rev.
Information Technology Firms: Creating Value through Digital Disruption
Information technology (IT) firms compose the majority of the most highly valued corporations in the world based on market capitalization. To date, only Apple and Amazon—both IT companies—have reached or nearly reached a USD trillion-dollar market capitalization. The value that IT provides speaks to how managers exploit disruptive technologies to create value in both IT and non-IT firms. A panel held at the 2018 Americas Conference on Information Systems (AMCIS) discussed various ways in firms build value around IT through successful management. This paper reports on the panel discussion from a variety of perspectives, which include practitioner and researcher worldviews. This panel report also provides a sample frame that researchers can use in quantitative research involving IT firms and advocates for increased research to understand the wide range of strategies IT firms use to create value
New ADS Functionality for the Curator
In this paper we provide an update concerning the operations of the NASA
Astrophysics Data System (ADS), its services and user interface, and the
content currently indexed in its database. As the primary information system
used by researchers in Astronomy, the ADS aims to provide a comprehensive index
of all scholarly resources appearing in the literature. With the current effort
in our community to support data and software citations, we discuss what steps
the ADS is taking to provide the needed infrastructure in collaboration with
publishers and data providers. A new API provides access to the ADS search
interface, metrics, and libraries allowing users to programmatically automate
discovery and curation tasks. The new ADS interface supports a greater
integration of content and services with a variety of partners, including ORCID
claiming, indexing of SIMBAD objects, and article graphics from a variety of
publishers. Finally, we highlight how librarians can facilitate the ingest of
gray literature that they curate into our system.Comment: Submitted to the Proceedings of Library and Information Services in
Astronomy VIII, Strasbourg, Franc
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