University of North Texas

About: University of North Texas is a education organization based out in Denton, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 11866 authors who have published 26984 publications receiving 705376 citations. The organization is also known as: Fight, North Texas & UNT.

Civil War Destruction and the Prospects for Economic Growth

Abstract: This article examines the effects of civil wars on economies. The “war renewal” school of thought maintains that wars can produce beneficial effects as they improve efficiency in the economy, especially by reducing the power of special interests, bring technological innovation, and advance human capital. The “war ruin” school of thought sees mostly detrimental effects resulting from war. We seek to address two critical questions. First, which perspective on wars and economic growth is more accurate? Second, to what extent do policy choices at both the domestic and international levels exert influence on economic growth? We develop several hypotheses to assess these arguments, and utilizing a 2SLS model, test them on data for all nations for the period 1960–2002. We find that generally wars exercise negative economic effects and that economic fundamentals, as well as the response by the international community to civil wars, exert powerful effects on economic growth.

Optically selected BL Lacertae candidates from the Sloan Digital Sky Survey Data Release Seven

Abstract: We present a sample of 723 optically selected BL Lac candidates from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) spectroscopic database encompassing 8250?deg2 of sky; our sample constitutes one of the largest uniform BL Lac samples yet derived. Each BL Lac candidate has a high-quality SDSS spectrum from which we determine spectroscopic redshifts for ~60% of the objects. Redshift lower limits are estimated for the remaining objects utilizing the lack of host galaxy flux contamination in their optical spectra; we find that objects lacking spectroscopic redshifts are likely at systematically higher redshifts. Approximately 80% of our BL Lac candidates match to a radio source in FIRST/NVSS, and ~40% match to a ROSAT X-ray source. The homogeneous multiwavelength coverage allows subdivision of the sample into 637 radio-loud BL Lac candidates and 86 weak-featured radio-quiet objects. The radio-loud objects broadly support the standard paradigm unifying BL Lac objects with beamed radio galaxies. We propose that the majority of the radio-quiet objects may be lower-redshift (z < 2.2) analogs to high-redshift weak line quasars (i.e., active galactic nucleus with unusually anemic broad emission line regions). These would constitute the largest sample of such objects, being of similar size and complementary in redshift to the samples of high-redshift weak line quasars previously discovered by the SDSS. However, some fraction of the weak-featured radio-quiet objects may instead populate a rare and extreme radio-weak tail of the much larger radio-loud BL Lac population. Serendipitous discoveries of unusual white dwarfs, high-redshift weak line quasars, and broad absorption line quasars with extreme continuum dropoffs blueward of rest-frame 2800?? are also briefly described.

Testosterone increases neurotoxicity of glutamate in vitro and ischemia-reperfusion injury in an animal model

Abstract: Increasing evidence has demonstrated striking sex differences in the outcome of neurological injury. Whereas estrogens contribute to these differences by attenuating neurotoxicity and ischemia-repe...

Electrical characteristics and pressure-sensitive response measurements of carboxyl MWNT/cement composites

Abstract: In this study, electrical characteristics of pressure-sensitive carboxyl multi-walled carbon nanotube (MWNT)/cement composites with and without compressive loading were investigated. Experimental results indicate that the carboxyl MWNT/cement composites have both resistance and capacitance characteristics. Capacitance is insensitive to compressive loading, but the charging of the capacitor causes a linear increase in the measured resistance during DC measurement. The reversible pressure-sensitive responses of resistance to compressive loading can be extracted by removing the linear increase component. An AC measurement method can also be used to eliminate the effect of capacitor charging and discharging on the pressure-sensitive responses of carboxyl MWNT/cement composites.

Interaction in information retrieval: selection and effectiveness of search terms

Abstract: We investigated the sources and effectiveness of search terms used during mediated on-line searching under real-life (as opposed to laboratory) circumstances. A stratified model of information retrieval (IR) interaction served as a framework for the analysis. For the analysis, we used the on-line transaction logs, videotapes, and transcribed dialogue of the presearch and on-line interaction between 40 users and 4 professional intermediaries. Each user provided one question and interacted with one of the four intermediaries. Searching was done using DIALOG. Five sources of search terms were identified: (1) the users' written question statements, (2) terms derived from users' domain knowledge during the interaction, (3) terms extracted from retrieved items as relevance feedback, (4) database thesaurus, and (5) terms derived by intermediaries during the interaction. Distribution, retrieval effectiveness, transition sequences, and correlation of search terms from different sources were investigated. Search terms from users' written question statements and term relevance feedback were the most productive sources of terms contributing to the retrieval of items judged relevant by users. Implications of the findings are discussed. © 1997 John Wiley & Sons, Inc.