Selection into Mixed Marriages: Evidence from North Carolina, 1894-1906

Using a novel dataset from agricultural censuses and geological sources, I examine the selec- tion into mixed marriages between whites and Cherokee Indians in North Carolina during the late nineteenth century. I find that the well-documented wealth advantage of Cherokee Indian households containing white husbands is driven mostly by positive selection. Thus, once family fixed effects are controlled for, the observed intermarriage premium is completely eliminated. (JEL D03, N31, O12.

Cultural persistence as behavior towards risk: evidence from the North Carolina Cherokees, 1850-1880

Can economic theory help explain the persistence of a cultural enclave among the Cherokee Indians living in North Carolina during the nineteenth century? To date, Fogelson and Kutsche (1961) and Finger (1984) identify the continuation of a communal, labor-sharing agricultural institution called the gadugi as simply an example of Cherokee agency during a period of substantial upheaval. I contribute to the historiography on ancestral labor traditions by adopting Kimball's (1988) framework on the function of farming cooperatives to test whether this arrangement sprung up as a form of insurance against the idiosyncratic risk inherent in southern agriculture. Data collected from the 1850-1880 manuscript census returns on North Carolina Cherokee farms are used to compute the variance of household self-sufficiency, which appears substantial enough to warrant a non-market mechanism to pool risk.Risk-Sharing; Cooperatives; Cherokee Indians

Orbital causes of incomitant strabismus

Strabismus may result from abnormal innervation, structure, or function of the extraocular muscles. Abnormalities of the orbital bones or masses within the orbit may also cause strabismus due to indirect effects on the extraocular muscles. This paper reviews some disorders of the orbit that are associated with strabismus, including craniofacial malformations, orbital masses, trauma, and anomalous orbital structures

The jamming transition and new percolation universality classes in particulate systems with attraction

We numerically study the jamming transition in particulate systems with attraction by investigating their mechanical response at zero temperature. We find three regimes of mechanical behavior separated by two critical transitions--connectivity and rigidity percolation. The transitions belong to different universality classes than their lattice counterparts, due to force balance constraints. We also find that these transitions are unchanged at low temperatures and resemble gelation transitions in experiments on colloidal and silica gels.Comment: 4 pages, 2 figures, 2 table

Kolmogorov Similarity Hypotheses for Scalar Fields: Sampling Intermittent Turbulent Mixing in the Ocean and Galaxy

Kolmogorov's three universal similarity hypotheses are extrapolated to describe scalar fields like temperature mixed by turbulence. By the analogous Kolmogorov third hypothesis for scalars, temperature dissipation rates chi averaged over lengths r > L_K should be lognormally distributed with intermittency factors I that increase with increasing turbulence energy length scales L_O as I_chi-r = m_T ln(L_O/r). Tests of Kolmogorovian velocity and scalar universal similarity hypotheses for very large ranges of turbulence length and time scales are provided by data from the ocean and the Galactic interstellar medium. The universal constant for turbulent mixing intermittency m_T is estimated from oceanic data to be 0.44+-0.01, which is remarkably close to estimates for Kolmogorov's turbulence intermittency constant m_u of 0.45+-0.05 from Galactic as well as atmospheric data. Extreme intermittency complicates the oceanic sampling problem, and may lead to quantitative and qualitative undersampling errors in estimates of mean oceanic dissipation rates and fluxes. Intermittency of turbulence and mixing in the interstellar medium may be a factor in the formation of stars.Comment: 23 pages original of Proc. Roy. Soc. article, 8 figures; in "Turbulence and Stochastic Processes: Kolmogorov's ideas 50 years on", London The Royal Society, 1991, J.C.R. Hunt, O.M. Phillips, D. Williams Eds., pages 1-240, vol. 434 (no. 1890) Proc. Roy. Soc. Lond. A, PDF fil

ACE: An Expert System Supporting Analysis and Management Decision Making

ACE, a system for Automated Cable Expertise, is a Knowledge-Based Expert System designed to provide trouble-shooting reports and management analyses for telephone cable maintenance in a timely manner. Many design decisions faced during the construction of ACE were guided by recent successes in expert systems technology, most notably R1/XCON, the Digital Equipment Corporation Vax configuration program. The most significant departure from "standard" expert systems architectures is ACE's use of a conventional data base management system as its primary source of information. Its primary sources of knowledge are the expert users of the database system, and primers on maintenance analysis strategies. The coupling of "knowledge-base" and "data-base" demonstrates in a forceful way the manner in which an expert system can significantly enhance the throughput and quality of data processing environments supporting business management. However, further difficult problems must be solved before the expert system approach becomes a standard technique in the data processing industry

The geochemistry of stream sediments, Panama: weathering in a tropical watershed

Chemical weathering of Earth's surface is the primary process controlling landscape and soil development, as well as the geochemistry of natural waters. In addition, chemical weathering of silicate minerals, which consumes atmospheric C02, is a major control of long-term climate variation. Although much has been published related to the rates and intensities of chemical weathering for temperate and high-latitude settings, few data exist on chemical weathering in mountainous tropical regions. This study focuses on the Rio Chagres watershed. The Rio Chagres is one of Panama's most important rivers. This 414 krn2 watershed produces a total runoff of 4.4xl 05 m3 per year during years of higher flow, supplying almost half the water required to operate the Panama Canal. The highest areas of the watershed rise to elevations of 1000m. The high rainfall (c.2000mm/yr), warm temperatures (mean annual T° ~ 19°C), and steep forested topography all increase rates of chemical weathering in the watersheds relative to more temperate geographic settings. Samples have been analyzed for the purpose of establishing the intensity of chemical weathering in this environment using X-Ray Fluorescence Spectroscopic (XRF) techniques for both major and trace element composition. Stream sediment geochemistry has been compared to the geochemistry of local bedrock lithologies and normalized to upper continental crust values. XRF analyses of sediments from the Rio Chagres headwaters demonstrate depletion in Ca2+, Sr2+, Ba2+, K+ and Rb+ relative to average upper continental crust, suggesting rapid loss of these elements. Grain-size analyses of the stream sediments suggest there is a positive relationship between sediment size, the rate of chemical weathering and the watershed geology. Watersheds draining mostly altered volcanic lithologies have mainly sand-size sediments by comparison to watersheds draining mainly intrusive mafic lithologies which tend to have coarser sediments. These data, combined with previously reported water geochemical data, suggest intensive weathering of the altered volcanic lithologies and that the intrusive mafic lithologies are not being weathered at the same rate or intensity as the volcanic lithologies.No embarg

The association of neonatal dacryocystoceles and infantile dacryocystitis with nasolacrimal duct cysts (an American Ophthalmogical Society Thesis)

PURPOSE: To investigate whether neonatal dacryocystoceles and dacryocystitis are associated with nasolacrimal duct cysts, and to report the outcomes of treatment of these disorders. METHODS: This was a retrospective medical record review of two groups of infants with nasolacrimal duct (NLD) obstruction. The first group had dacryocystoceles with or without dacryocystitis. The second group had NLD obstruction with symptoms severe enough to require early NLD probing. All of the patients underwent NLD probing and nasal endoscopy. When present, NLD cysts were removed. RESULTS: In the first group, 33 infants had dacryocystoceles. Acute dacryocystitis was present in 16 patients, 12 had noninfected dacryocystoceles that did not resolve, and 5 had dacryocystoceles that resolved but severe symptoms persisted. All of the patients had NLD cysts that were surgically removed. The symptoms resolved after surgery in 31 patients (94%). In the second group, 27 infants less than 6 months old without dacryocystoceles underwent early NLD probing and endoscopy due to severity of symptoms. Twelve (44%) of these patients had NLD cysts. The symptoms resolved in 11 (92%) of 12 patients following NLD probing and cyst removal. CONCLUSIONS: Neonatal dacryocystoceles are almost always associated with NLD cysts. The success rate of NLD probing and endoscopic cyst removal in these patients is excellent. Nasolacrimal duct cysts also are present in many young infants with severe symptoms of NLD obstruction. Nasal endoscopy is an important adjunct to the management of these infants

Route Generation for a Synthetic Character (BOT) Using a Partial or Incomplete Knowledge Route Generation Algorithm in UT2004 Virtual Environment

This paper presents a new Route Generation Algorithm that accurately and realistically represents human route planning and navigation for Military Operations in Urban Terrain (MOUT). The accuracy of this algorithm in representing human behavior is measured using the Unreal Tournament(Trademark) 2004 (UT2004) Game Engine to provide the simulation environment in which the differences between the routes taken by the human player and those of a Synthetic Agent (BOT) executing the A-star algorithm and the new Route Generation Algorithm can be compared. The new Route Generation Algorithm computes the BOT route based on partial or incomplete knowledge received from the UT2004 game engine during game play. To allow BOT navigation to occur continuously throughout the game play with incomplete knowledge of the terrain, a spatial network model of the UT2004 MOUT terrain is captured and stored in an Oracle 11 9 Spatial Data Object (SOO). The SOO allows a partial data query to be executed to generate continuous route updates based on the terrain knowledge, and stored dynamic BOT, Player and environmental parameters returned by the query. The partial data query permits the dynamic adjustment of the planned routes by the Route Generation Algorithm based on the current state of the environment during a simulation. The dynamic nature of this algorithm more accurately allows the BOT to mimic the routes taken by the human executing under the same conditions thereby improving the realism of the BOT in a MOUT simulation environment