2,115 research outputs found
Mountain uplift and the glaciation of North America – a sensitivity study
No full textThe Miocene (24 to 5 million years ago) wasa period of relative global warmth compared to the Quaternary(2 million years ago to present; e.g. Zachos et al.,2001) and was characterised by the intermittent glaciationof Antarctica only. Paradoxically, the majority of availableproxy data suggest that during the Miocene, pCO2 was similar,or even lower, than the pre-industrial levels (280 ppmv;Pagani et al., 1999; Pearson and Palmer, 2000; K¨urschneret al., 1996, 2008) and at times probably crossed the modelledthreshold value required for sustained glaciation in theNorthern Hemisphere (DeConto et al., 2008). Records ofice rafted debris and the oxygen isotope composition of benthicforaminifera suggest that at several times over the last25 million years substantial amounts of continental ice didbuild up in the Northern Hemisphere but none of these ledto prolonged glaciation. In this contribution, we review evidencethat suggests that in the Miocene the North AmericanCordillera was, at least in parts, considerably lower than today.We present new GCM simulations that imply that smallamounts of uplift of the North American Cordillera resultin significant cooling of the northern North American Continent.Offline ice sheet modelling, driven by these GCMoutputs, suggests that with a reduced topography, inceptionof the Cordilleran ice sheet is prohibited. This suggests thatuplift of the North American Cordillera in the Late Miocenemay have played an important role in priming the climate forthe intensification of Northern Hemisphere glaciation in theLate Pliocene
Using Private Contracts to Create Adoptions from Foster Care
No full textCreating adoptions for children waiting in foster care is a good investment, but the number of adoptions created each year meets only a fraction of the need. This paper explores how the organization of the delivery of social services to waiting children and prospective adoptive families influences adoption creation. Cross-section time-series estimates are supplemented with a new augmented fixed effects procedure to demonstrate that the use of contracts with private agencies bolsters adoption creation. Contracts for recruitment and orientation of prospective adoptive parents are particularly effective.adoption, child welfare, fixed effects vector decomposition, foster care, privatization
The generation of prograde P–T–t points and paths; a textural, compositional, and chronological study of metamorphic monazite
No full textEnhanced carbon dioxide outgassing from the eastern equatorial Atlantic during the last glacial
No full textBiological productivity and carbon export in the equatorial Atlantic are thought to have been dramatically higher during the last glacial period than during the Holocene. Here we reconstruct the pH and CO2 content of surface waters from the eastern equatorial Atlantic Ocean over the past ?30 k.y. using the boron isotope composition of Globigerinoides ruber (a mixed-layer–dwelling planktic foraminifera). Our new record, combined with previously published data, indicates that during the last glacial, in contrast to today, a strong west to east gradient existed in the extent of air:sea equilibrium with respect to pCO2 (?pCO2), with the eastern equatorial Atlantic acting as a significant source of CO2 (+100 ?atm) while the western Atlantic remained close to equilibrium (+25 ?atm). This pattern suggests that a fivefold increase in the upwelling rate of deeper waters drove increased Atlantic productivity and large-scale regional cooling during the last glacial, but the higher than modern ?pCO2 in the east indicates that export production did not keep up with enhanced upwelling of nutrients. However, the downstream decline of ?pCO2 provides evidence that the unused nutrients from the east were eventually used for biologic carbon export, thereby effectively negating the impact of changes in upwelling on atmospheric CO2 levels. Our findings indicate that the equatorial Atlantic exerted a minimal role in contributing to lower glacial-age atmospheric CO2
What is the Time Limit for Filing a Lawsuit? It Depends on What Your Definition of Arising Under Is! An Analysis of Jones v. R.R. Donnelley & Sons Co.
No full textThis article previews the Supreme Court case Jones et. al. v. R.R. Donnelly & Sons Co., 541 U.S. 369 (2004). The author predicted that the case would require the court to determine the appropriate statute of limitations to apply in a class action race-discrimination lawsuit filed under 42 U.S.C. § 1981
Dynamic synchromodal transport planning under uncertainty: A reinforcement learning approach
No full textAccepted Author ManuscriptTransport Engineering and Logistic
The Scope of Employer Liability for Employee Exposure to a Hazardous Substance: No Harm, No Foul? An Analysis of Metro-North Commuter R.R. Co. v. Buckley
No full textThis article previews the Supreme Court case Metro-North Commuter R.R. Co. v. Buckley, 521 U.S. 424 (1997). The author expected the Court to decide whether a railroad worker who is covered by the Federal Employer\u27s Liability Act who has been exposed to asbestos because of employer negligence but who has not developed an asbestos-related disease can recover damages for emotional distress caused by the exposure
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