2,552 research outputs found
An Enhanced Spectroscopic Census of the Orion Nebula Cluster
We report new spectral types or spectral classification constraints for over
600 stars in the Orion Nebula Cluster (ONC) based on medium resolution R~
1500-2000 red optical spectra acquired using the Palomar 200" and Kitt Peak
3.5m telescopes. Spectral types were initially estimated for F, G, and early K
stars from atomic line indices while for late K and M stars, constituting the
majority of our sample, indices involving TiO and VO bands were used. To ensure
proper classification, particularly for reddened, veiled, or
nebula-contaminated stars, all spectra were then visually examined for type
verification or refinement. We provide an updated spectral type table that
supersedes Hillenbrand (1997), increasing the percentage of optically visible
ONC stars with spectral type information from 68% to 90%. However, for many
objects, repeated observations have failed to yield spectral types primarily
due to the challenges of adequate sky subtraction against a bright and
spatially variable nebular background. The scatter between our new and our
previously determined spectral types is approximately 2 spectral sub-classes.
We also compare our grating spectroscopy results with classification based on
narrow-band TiO filter photometry from Da Rio et al. (2012, finding similar
scatter. While the challenges of working in the ONC may explain much of the
spread, we highlight several stars showing significant and unexplained bona
fide spectral variations in observations taken several years apart; these and
similar cases could be due to a combination of accretion and extinction
changes. Finally, nearly 20% of ONC stars exhibit obvious Ca II triplet
emission indicative of strong accretion.Comment: Accepted to the Astronomical Journal; 37 pages, including 11 Figures
and 3 Tables (one long table not reproduced here but available upon request
or from the journal
Snow cover monitoring by machine processing of multitemporal LANDSAT MSS data
LANDSAT frames were geometrically corrected and data sets from six different dates were overlaid to produce a 24 channel (six dates and four wavelength bands) data tape. Changes in the extent of the snowpack could be accurately and easily determined using a change detection technique on data which had previously been classified by the LARSYS software system. A second phase of the analysis involved determination of the relationship between spatial resolution or data sampling frequency and accuracy of measuring the area of the snowpack
Up In The Air: How Airlines Can Improve Performance by Engaging Their Employees
[Excerpt] In the chapters that follow, we explore the competitive strategies and employment-relations strategies found in the United States (chapter 2) and in a range of other countries (chapter 3), before and after deregulation. In chapter 4 we analyze recent trends in quality, productivity, and costs, as well as employee outcomes. In chapter 5 we look more closely at selected new-entrant airlines and find a wide range of competitive and employment-relations strategies being used in this segment of the industry. In chapter 6, we examine several legacy airlines and identify the distinct strategies they have adopted to respond to competitive pressures from new-entrant airlines. These chapters each focus on selected U.S. airlines and those based in some other countries. In chapter 7, we summarize the strategies of new-entrant and legacy airlines, and offer lessons about how airlines can and do change their strategies over time in their efforts to compete more effectively.
We offer recommendations, using our historical and comparative analyses to discuss whether a path forward can be identified that can provide a better balance in stakeholder outcomes. We end on a positive note, arguing that if the parties learn from their experiences and from each other, in the United States and other countries, there is a path that deals with the pressures building up in the airline industry, offering hope for a better balance between investor, employee, customer, and societal interests. Key questions are whether and from where the leadership will come to get the industry moving down this path or whether the main parties might not take such action before there is a perfect storm
Tax-Free Reorganizations: The Evolution and Revolution of Triangular Mergers
Tax laws applicable to triangular mergers lack neutrality, are
complex, and overlap substantially with other tax-preferred forms of
corporate acquisition. Their current status is a result of both path
dependency and Congress's attempt to create consistency within a
framework founded upon inconsistent conceptualizations of the
corporation. This Article highlights problems arising under current rules,
including a notable lack of tax neutrality among merger forms. It proposes
pragmatic revisions made within the constraint of double taxation of
corporate profits and then revisits the question through a more normative
framework. The Article concludes that the tax treatment of target
shareholders and the target corporation in corporate acquisitions should be
disaggregated. Finally, it observes that both pragmatic and normative
solutions proposed within the reorganization statute are unsatisfying in
light of larger structural problems in the Internal Revenue Code
Teradata University Network: A New Resource for Teaching Large Data Bases and Their Applications
A free learning portal designed to help faculty to teach, learn, and connect with others in the fields of data warehousing, DSS/BI, and database is being made available by Teradata, a division of NCR. Teradata worked closely with leading academics to create the Teradata University Network (www.teradatauniversitynetwork.com). The network is reached by faculty through a portal that includes (1) course syllabi; (2) access to software; (2) Power Point presentations (with speaker\u27s notes); (4) cases, projects, and assignments (with teaching notes); (5) book chapters, articles, and research reports; (6) the Teradata library; (7) web-based courses; and (8) links to related sites. In addition, a separate portal for students, located at www.teradatastudentnetwork.com, leads to a subset of the above materials, including (1) access to software; (2) cases, projects, and assignments (without teaching notes); (3) book chapters, articles, and research reports; (4) the Teradata library; and (5) links to related sites. The student site excludes materials that are only for course instructors. This tutorial describes the creation of the Teradata University Network (TUN), discusses how faculty access and use TUN, describes how a faculty member might use it in a typical session, and faculty reactions to TUN. Special attention is given to the software available on TUN and TSN. It also discusses working with Teradata and TUN and provides lessons learned to help other faculty involved in vendor-supported initiatives
Summarizing First-Person Videos from Third Persons' Points of Views
Video highlight or summarization is among interesting topics in computer
vision, which benefits a variety of applications like viewing, searching, or
storage. However, most existing studies rely on training data of third-person
videos, which cannot easily generalize to highlight the first-person ones. With
the goal of deriving an effective model to summarize first-person videos, we
propose a novel deep neural network architecture for describing and
discriminating vital spatiotemporal information across videos with different
points of view. Our proposed model is realized in a semi-supervised setting, in
which fully annotated third-person videos, unlabeled first-person videos, and a
small number of annotated first-person ones are presented during training. In
our experiments, qualitative and quantitative evaluations on both benchmarks
and our collected first-person video datasets are presented.Comment: 16+10 pages, ECCV 201
Agricultural scene understanding
The author has identified the following significant results. The LACIE field measurement data were radiometrically calibrated. Calibration enabled valid comparisons of measurements from different dates, sensors, and/or locations. Thermal band canopy results included: (1) Wind velocity had a significant influence on the overhead radiance temperature and the effect was quantized. Biomass and soil temperatures, temperature gradient, and canopy geometry were altered. (2) Temperature gradient was a function of wind velocity. (3) Temperature gradient of the wheat canopy was relatively constant during the day. (4) The laser technique provided good quality geometric characterization
N-Acetylcysteine enhances the action of anti-inflammatory drugs as suppressors of prostaglandin production in monocytes.
The anti-inflammatory effect of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with inhibition of cyclooxygenase (COX), the rate-limiting enzyme responsible for the synthesis of prostaglandins. Since oxygen free radicals can act as second cellular messengers, especially to modulate the metabolism of arachidonic acid and the prostaglandin tract, it seems plausible that antioxidants might affect the production of prostaglandin by activated cells. This research is focused on the effect of the antioxidant N-acetylcysteine (NAC) on the inhibition of prostaglandin E(2) formation in activated monocytes by specific and non-specific COX inhibitors. We found that lipopolysaccharide-induced prostaglandin E(2) formation was significantly reduced by rofecoxib and by diclofenac, two NSAIDs. Addition of NAC to each of these drugs enhanced the effect of the NSAIDs. These results suggest that one might expect either a potentiation of the anti-inflammatory effect of COX inhibitors by their simultaneous administration with NAC, or obtaining the same anti-inflammatory at lower drug levels
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