109 research outputs found
Using Real Options Analysis for Evaluating Uncertain Investments in Information Technology: Insights from the ICIS 2001 Debate
Business and information systems (IS) executives continue to grapple with issues of risk and uncertainty in evaluating investments in information technology (IT). Despite the use of net present value (NPV) and other investment appraisal techniques, executives are often forced to rely on instinct when finalizing IT investment decisions. Recognizing the shortcomings of NPV, real options analysis has been suggested as an alternative approach, one that considers the risks associated with an investment while recognizing the ability of corporations to defer an investment until a later period or to make a partial investment instead. Responding to a growing interest in real options analysis among the IS community, a debate involving four prominent researchers was convened at the 2001 International Conference on Information Systems (ICIS). In addition to offering a tutorial overview of real options, the goal of the debate was to assess the state of research in this area and to identify avenues for future research. This paper describes the outcomes of the debate, culminating in a series of research questions and topics that set the stage for future research in IT and real options analysis. A transcript of the debate and an overview of real options analysis are included as appendices
The dearth of halo dwarf galaxies: is there power on short scales?
N-body simulations of structure formation with scale-invariant primordial
perturbations show significantly more virialized objects of dwarf-galaxy mass
in a typical galactic halo than are observed around the Milky Way. We show that
the dearth of observed dwarf galaxies could be explained by a dramatic downturn
in the power spectrum at small distance scales. This suppression of small-scale
power might also help mitigate the disagreement between cuspy simulated halos
and smooth observed halos, while remaining consistent with Lyman-alpha-forest
constraints on small-scale power. Such a spectrum could arise in inflationary
models with broken scale invariance.Comment: 5 pages LaTeX, 3 figure
Additional experimental evidence for a solar influence on nuclear decay rates
Additional experimental evidence is presented in support of the recent
hypothesis that a possible solar influence could explain fluctuations observed
in the measured decay rates of some isotopes. These data were obtained during
routine weekly calibrations of an instrument used for radiological safety at
The Ohio State University Research Reactor using Cl-36. The detector system
used was based on a Geiger-Mueller gas detector, which is a robust detector
system with very low susceptibility to environmental changes. A clear annual
variation is evident in the data, with a maximum relative count rate observed
in January/February, and a minimum relative count rate observed in July/August,
for seven successive years from July 2005 to June 2011. This annual variation
is not likely to have arisen from changes in the detector surroundings, as we
show here.Comment: 8 pages, 6 figure
Complex dynamics of elementary cellular automata emerging from chaotic rules
We show techniques of analyzing complex dynamics of cellular automata (CA)
with chaotic behaviour. CA are well known computational substrates for studying
emergent collective behaviour, complexity, randomness and interaction between
order and chaotic systems. A number of attempts have been made to classify CA
functions on their space-time dynamics and to predict behaviour of any given
function. Examples include mechanical computation, \lambda{} and Z-parameters,
mean field theory, differential equations and number conserving features. We
aim to classify CA based on their behaviour when they act in a historical mode,
i.e. as CA with memory. We demonstrate that cell-state transition rules
enriched with memory quickly transform a chaotic system converging to a complex
global behaviour from almost any initial condition. Thus just in few steps we
can select chaotic rules without exhaustive computational experiments or
recurring to additional parameters. We provide analysis of well-known chaotic
functions in one-dimensional CA, and decompose dynamics of the automata using
majority memory exploring glider dynamics and reactions
The Pennsylvania Dutchman Vol. 8, No. 1
â The Summer House â Drinks in Dutchland â Yesteryear in Dutchland â Moshey and Bellyguts â Rise of Interest in Dutch Antiques â Diaper Lore â Lititz â Witchcraft in Cow and Horse â Dorothy Kalbach â Plain Dutch and Gay Dutch â Dialect Folksay â Pennsylvania Dutch Pioneers â About the Authors â What\u27s New in Dutchlandhttps://digitalcommons.ursinus.edu/dutchmanmag/1008/thumbnail.jp
The DEEP Groth Strip Survey XII: The Metallicity of Field Galaxies at 0.26<z<0.82 and the Evolution of the Luminosity-Metallicity Relation
Using spectroscopic data from the Deep Extragalactic Evolutionary Probe
(DEEP) Groth Strip survey (DGSS), we analyze the gas-phase oxygen abundances
for 56 emission-line field galaxies in the redshift range 0.26<z<0.82. Oxygen
abundances relative to hydrogen range between 8.4<12+log(O/H)<9.0 with typical
uncertainties of 0.17 dex. The 56 DGSS galaxies collectively exhibit a
correlation between B-band luminosity and metallicity, i.e., an L-Z relation.
Subsets of DGSS galaxies binned by redshift also exhibit L-Z correlations but
with different zero points. Galaxies in the highest redshift bin (z=0.6-0.82)
are brighter by ~1 mag compared to the lowest redshift bin (z=0.26-0.40) and
brighter by ~1-2 mag compared to local (z<0.1) field galaxies. This offset from
the local L-Z relation is greatest for objects at the low-luminosity (M_B ~
-19) end of the sample, and vanishingly small for objects at the
high-luminosity end of the sample (M_B ~ -22). Thus, both the slope and zero
point of the L-Z relation appear to evolve. Either the least-luminous DGSS
field galaxies have faded by 1--2 mag due to decreasing levels of star
formation, or they have experienced an increase in the mean metallicity of the
interstellar medium by factors of 1.3--2 (0.1-0.3 dex). The relatively greater
degree of luminosity and metallicity evolution seen among the lower luminosity
(sub L*) galaxies in the last 8 Gyr implies either a more protracted assembly
process, or a more recent formation epoch compared to more luminous L*
galaxies. (abridged)Comment: Submitted to ApJ, comments welcome; 43 pages, 14 figures Version with
full figures available at http://physics.uwyo.edu/~chip/Pubs/Grot
Growth and Institutions in the Transition: How Do Belarus, Russia, and Ukraine Compare to Others
Acetaminophen Modulates the Transcriptional Response to Recombinant Interferon-ÎČ
BACKGROUND: Recombinant interferon treatment can result in several common side effects including fever and injection-site pain. Patients are often advised to use acetaminophen or other over-the-counter pain medications as needed. Little is known regarding the transcriptional changes induced by such co-administration. METHODOLOGY/PRINCIPAL FINDINGS: We tested whether the administration of acetaminophen causes a change in the response normally induced by interferon-beta treatment. CD-1 mice were administered acetaminophen (APAP), interferon-beta (IFN-beta) or a combination of IFN-beta+APAP and liver and serum samples were collected for analysis. Differential gene expression was determined using an Agilent 22 k whole mouse genome microarray. Data were analyzed by several methods including Gene Ontology term clustering and Gene Set Enrichment Analysis. We observed a significant change in the transcription profile of hepatic cells when APAP was co-administered with IFN-beta. These transcriptional changes included a marked up-regulation of genes involved in signal transduction and cell differentiation and down-regulation of genes involved in cellular metabolism, trafficking and the IkappaBK/NF-kappaB cascade. Additionally, we observed a large decrease in the expression of several IFN-induced genes including Ifit-3, Isg-15, Oasl1, Zbp1 and predicted gene EG634650 at both early and late time points. CONCLUSIONS/SIGNIFICANCE: A significant change in the transcriptional response was observed following co-administration of IFN-beta+APAP relative to IFN-beta treatment alone. These results suggest that administration of acetaminophen has the potential to modify the efficacy of IFN-beta treatment
Moving in the anthropocene: global reductions in terrestrial mammalian movements
Animal movement is fundamental for ecosystem functioning and species survival, yet the effects of the anthropogenic footprint on animal movements have not been estimated across species. Using a unique GPS-tracking database of 803 individuals across 57 species, we found that movements of mammals in areas with a comparatively high human footprint were on average one-half to one-third the extent of their movements in areas with a low human footprint. We attribute this reduction to behavioral changes of individual animals and to the exclusion of species with long-range movements from areas with higher human impact. Global loss of vagility alters a key ecological trait of animals that affects not only population persistence but also ecosystem processes such as predator-prey interactions, nutrient cycling, and disease transmission
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
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