3,086 research outputs found
An Epidemiology of Information: Data Mining the 1918 Influenza Pandemic
An Epidemiology of Information: Data Mining the 1918 Influenza Pandemic seeks to harness the power of data mining techniques with the interpretive analytics of the humanities and social sciences to understand how newspapers shaped public opinion and represented authoritative knowledge during this deadly pandemic. This project makes use of the more than 100 newspaper titles for 1918 available from Chronicling America at the United States Library of Congress and the Peel’s Prairie Provinces collection at the University of Alberta Library. The application of algorithmic techniques enables the domain expert to systematically explore a broad repository of data and identify qualitative features of the pandemic in the small scale as well as the genealogy of information flow in the large scale. This research can provide methods for understanding the spread of information and the flow of disease in other societies facing the threat of pandemics
Brevity, Speed, and Deference: An Account from the Williams Chambers
One of the leading books on administrative law advocates judicial review for “sound governance.”Reviewing the book while sitting on the D.C. Circuit, Judge Williams posited that, even if “judges are smarter than agency heads, or have more time on their hands, or have cleverer clerks,” the proper institutional role requires more deference. Divining “sound governance” is not for courts. The Judge concluded by quoting Milton’s poem about the role of the blind: “They also serve who only stand and waite.
Lunar mission safety and rescue Midterm presentation, Nov. 1970
Discussing major and minor tasks of safety and rescue planning for lunar mission
Energy Dissipation in Interstellar Cloud Collisions
We present a study of the kinetic energy dissipation in interstellar cloud
collisions. The main aim is to understand the dependence of the elasticity
(defined as the ratio of the final to the initial kinetic energy of the clouds)
on the velocity and mass ratio of the colliding clouds, magnetic field
strength, and gas metallicity for head-on collisions. The problem has been
studied both analytically and via numerical simulations. We have derived handy
analytical relationships that well approximate the analogous numerical results.
The main findings of this work are: (i) the kinetic energy dissipation in cloud
collisions is minimum (i.e. the collision elasticity is maximum) for a cloud
relative velocity ; (ii) the above minimum value is
proportional , where is the metallicity and is the cloud
size: the larger is the more dissipative (i.e. inelastic) the
collision will be; (iii) in general, we find that the energy dissipation
decreases when the magnetic field strength, and mass ratio of the clouds are
increased and the metallicity is decreased, respectively. We briefly discuss
the relevance of this study to the global structure of the interstellar medium
and to galaxy formation and evolution.Comment: 16 pages, aasms LaTeX, 7 figures. ApJ, accepte
Closed-Form Bayesian Inferences for the Logit Model via Polynomial Expansions
Articles in Marketing and choice literatures have demonstrated the need for
incorporating person-level heterogeneity into behavioral models (e.g., logit
models for multiple binary outcomes as studied here). However, the logit
likelihood extended with a population distribution of heterogeneity doesn't
yield closed-form inferences, and therefore numerical integration techniques
are relied upon (e.g., MCMC methods).
We present here an alternative, closed-form Bayesian inferences for the logit
model, which we obtain by approximating the logit likelihood via a polynomial
expansion, and then positing a distribution of heterogeneity from a flexible
family that is now conjugate and integrable. For problems where the response
coefficients are independent, choosing the Gamma distribution leads to rapidly
convergent closed-form expansions; if there are correlations among the
coefficients one can still obtain rapidly convergent closed-form expansions by
positing a distribution of heterogeneity from a Multivariate Gamma
distribution. The solution then comes from the moment generating function of
the Multivariate Gamma distribution or in general from the multivariate
heterogeneity distribution assumed.
Closed-form Bayesian inferences, derivatives (useful for elasticity
calculations), population distribution parameter estimates (useful for
summarization) and starting values (useful for complicated algorithms) are
hence directly available. Two simulation studies demonstrate the efficacy of
our approach.Comment: 30 pages, 2 figures, corrected some typos. Appears in Quantitative
Marketing and Economics vol 4 (2006), no. 2, 173--20
The (d,6-Li) Reaction Studies
Supported by the National Science Foundation and Indiana Universit
The smaller the market, the better the rent capturing: electrification in North Portugal during the Interwar Period
This article analyses the origin of the persistently high level of electricity
prices that hampered the expansion of electricity consumption during the interwar period in Porto. Initially, the rent-seeking behaviour of both the supply firm and the City Hall at the local level affected the expansion of the local electricity market. During the 1930s, this collusion at municipal level coincided with unpredictable energy policies at state level. This circumstance impeded the indispensable increase of scale and the building of a regional market of electricity in north Portugal. The literature on regulation and institutional analysis has proved very useful. Finally, though equally important, primary sources from company archives and institutional bodies were also employed.Este artículo analiza el origen de los elevados precios de la electricidad en Oporto entre las dos guerra mundiales y su secuela, su lenta electrificación. La colusión entre la compañía suministradora y el municipio limitó la expansión al comenzar el servicio hidroeléctrico; luego, la expectativa reiteradamente frustrada de una mayor intervención gubernamental fue en detrimento de mayores inversiones. Se impidió así el necesario aumento de escala, la plena integración del mercado eléctrico del Norte de Portugal y, en consecuencia, los precios eléctricos se mantuvieron elevados y la electrificación sufrió un persistente atraso. La adopción de una perspectiva institucional se ha revelado muy útil para esclarecer el funcionamiento de este mercado, que se ha examinado consultando fuentes empresariales, municipales y gubernamentales.This research has been financed by the Fundaçao Ciência e Tecnologia de Portugal
A panel analysis of UK industrial company failure
We examine the failure determinants for large quoted UK industrials using a panel data set
comprising 539 firms observed over the period 1988-93. The empirical design employs data
from company accounts and is based on Chamberlain’s conditional binomial logit model,
which allows for unobservable, firm-specific, time-invariant factors associated with failure
risk. We find a noticeable degree of heterogeneity across the sample companies. Our panel
results show that, after controlling for unobservables, lower liquidity measured by the quick
assets ratio, slower turnover proxied by the ratio of debtors turnover, and profitability were
linked to the higher risk of insolvency in the analysis period. The findings appear to support
the proposition that the current cash-flow considerations, rather than the future prospects of
the firm, determined company failures over the 1990s recession
Obesity, Metabolic Syndrome, and Adipocytes
Obesity and metabolic syndromes are examples whereby excess energy consumption and energy flux disruptions are causative agents of increased fatness. Because other, as yet elucidated, cellular factors may be involved and because potential treatments of these metabolic problems involve systemic agents that are not adipose depot-specific in their actions, should we be thinking of adipose depot-specific (cellular) treatments for these problems? For sure, whether treating obesity or metabolic syndrome, the characteristics of all adipose depot-specific adipocytes and stromal vascular cells should be considered. The focus of this paper is to begin to align metabolic dysfunctions with specific characteristics of adipocytes
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