Optimal climate policy is studied in a Ramsey growth model. A developing economy weighs global warming less, hence is more likely to exhaust fossil fuel and exacerbate global warming. The optimal carbon tax is higher for a developed economy. We analyze the optimal time of transition from fossil fuel to renewables, amount of fossil fuel to leave in situ, and carbon tax. Subsidizing a backstop wi...

Organisms are extremely sensitive to many parameters of the physical environment, and their fossil remains may thus be used in the interpretation of ancient environments. Effective use of paleoecology depends on first determining what environmental parameters are of interest. Second, developing a model based on recent examples which can be tested on the fossil record, and third, testing the mod...

Using a significant quantity of fossil fuels has adverse impacts on our lives and will affect future generations. Additionally, there are limited and decreasing numbers of nonrenewable resources around the world. In contrast, renewable resources are not depleted and provide energy with negligible pollution. Wind energy is one of the more common renewable energy resources. This project aims to e...

T of woodpeckers and allies (Pici) is very poor, but the members of this group—barbets and toucans (Ramphastidae including “Capitonidae”; see Prum 1988); honeyguides (Indicatoridae); and woodpeckers, wrynecks, and piculets (Picidae)—today have an almost worldwide distribution and occur in most forested habitats (del Hoyo et al. 2002). Paleogene (pre-Miocene; i.e. older than 23 Ma) remains of th...

1 Universidad Autonoma del Carmen, Av. 56 # 4 X Av. Concordia, CP 24180, Cd. del Carmen, Campeche, Mexico, on Ph. D studies at CINVESTAV, Unidad Guadalajara, [email protected], 2 CINVESTAV, Unidad Guadalajara, Apartado Postal 31-430, Plaza La Luna, Guadalajara, Jalisco C.P. 45091, MEXICO, [email protected], 3 Instituto de Investigaciones Electricas, Calle Reforma # 113, Col. Palmira...

Asymmetry is a fundamental aspect of the biology of all organisms, and has a deep evolutionary history. The fossil record contains evidence of both morphological and behavioural asymmetries. Morphological asymmetry is most commonly expressed as conspicuous, directional asymmetry (either lateral asymmetry or spiral asymmetry) in body fossils. Few examples of fluctuating asymmetry, a form of subt...

The behaviour of fossil organisms can typically be inferred only indirectly, but rare fossil finds can provide surprising insights. Here, we report from the Eocene Messel Pit Fossil Site between Darmstadt and Frankfurt, Germany numerous pairs of the fossil carettochelyid turtle Allaeochelys crassesculpta that represent for the first time among fossil vertebrates couples that perished during cop...

Energy outputs from ethanol produced using corn, switchgrass, and wood biomass were each less than the respective fossil energy inputs. The same was true for producing biodiesel using soybeans and sunflower, however, the energy cost for producing soybean biodiesel was only slightly negative compared with ethanol production. Findings in terms of energy outputs compared with the energy inputs wer...

Fossils provide the principal basis for temporal calibrations, which are critical to the accuracy of divergence dating analyses. Translating fossil data into minimum and maximum bounds for calibrations is the most important-often least appreciated-step of divergence dating. Properly justified calibrations require the synthesis of phylogenetic, paleontological, and geological evidence and can be...